Speed change device

Technical Field

0001The present invention relates to a transmission apparatus having a dividing unit to which a rotational power from a drive unit is transmitted, a joint unit, and a first differential planetary gear unit, and specifically to a transmission apparatus used to rotate a fluid machinery such as a turbo machinery by a drive unit such as a motor for synchronizing a drive side and a driven side with each other, relieving an impact that occurs at starting/stopping or at changing in a rotational speed, and achieving an efficient transmission of a rotational power.

Background Art

0002In a conventional apparatus shown in <figref idref="f0019">FIG. 22</figref>, an output shaft C4 of an electric motor A1 serving as a drive source is connected to an input side of a driven unit A2 such as a fluid machinery via a joint A22 and an output shaft C7. In this case, transmission of a rotational power from the electric motor A1 is limited to a range in which the joint A22 can transmit the rotational power.

0003At the same time, there is a need to transmit a rotational power beyond the range in which the joint A22 can transmit the rotational power.

0004In order to meet such a need, as shown in <figref idref="f0020">FIGS. 23A and 23B</figref>, there has been proposed a transmission apparatus A15 which distributes or divides a rotational power that is input from a drive source A1.

0005According to the transmission apparatus A15 shown in <figref idref="f0020">FIGS. 23A and 23B</figref>, the rotational power from the drive source A1 is distributed to a power line R1 and a power line R2 by a dividing unit 6, so that the rotational power below the transmission limit of a continuously variable transmission A20 is distributed to the power line R1 and the residual rotational power is distributed to the power line R2.

0006The rotational powers divided by the dividing unit 6 are converged by a differential planetary gear unit A30 disposed at an output side of the continuously variable transmission A20, so that the converged rotational power is transmitted to a driven unit A2 via a single output shaft 37.

0007With this structure, the rotational power beyond the transmission limit of the continuously variable transmission A20 can be transmitted to the driven side.

0008However, the continuously variable transmission A20 shown in <figref idref="f0020">FIGS. 23A and 23B</figref> employs a mechanism of a toroidal-type continuously variable transmission (CVT). Since the toroidal-type CVT is of a contact type, there are limits to a maximum transmission power and a service life. Therefore, it is difficult to apply the toroidal-type CVT to a large equipment which is required to transmit a large power, and to an industrial machinery which is required to have a reliability.

0009Further, various kinds of vibrations and impacts, such as pulsation due to power fluctuation, shock vibration at speed change, and torsion vibration of the output shaft, are transmitted or occur to an output side of the toroidal-type CVT. Accordingly, the toroidal-type CVT, which utilizes solid friction, is problematic in output fluctuation and durability because of such vibrations and impacts.

0010In addition, another type of conventional transmission apparatus has the same problems.

0011<patcit id="pcit0001" dnum="JP60185699A"><text>JP 60 185 699 A</text></patcit> and <patcit id="pcit0002" dnum="US2615239A"><text>US-A- 2,615,239</text></patcit> disclose a ship gear train arrangement includes a differential gearing between a main input shaft and output shaft and a parallel shaft with a hydrodynamic coupling. The parallel shaft connects a point of the main input shaft on the input side of the differential gearing with a reaction element of the differential gearing. The coupling effect and thus also the speed of output shaft of the ship gear train arrangement can be changed smoothly down to zero speed by variation of the liquid level in the hydrodynamic coupling. The ship propeller can therefore be driven at a speed far lower than the lowest speed of the ship main drive motor.

0012<patcit id="pcit0003" dnum="JP9014176A"><text>JP 09-014 176 A</text></patcit> discloses a method of controlling the number of revolutions of a drainage pump. In order to improve operability and stability during control of the number of revolutions of a drainage pump by simultaneously controlling the gear shift operation rods of a plurality of variable speed fluid coupling in such a way to input a control signal to a single control motor, the output rotary shaft of a reduction gear is coupled to the main shaft of a drainage pump, first and second variable speed fluid couplings are located in a series between the input rotary shaft of the reduction gear and the output rotary shaft of a prime mover consisting of a diesel engine. The gear shift operation rod of each of the first and second variable speed fluid couplings is connected to the output rotary shaft of a single control motor through a power transmission mechanism, and float pipes coupled to the two gear shift operation rods are simultaneously moved forward and backward by the same amount.

0013<patcit id="pcit0004" dnum="JP57129931A"><text>JP 57-129,931 A</text></patcit> discloses a controller for the rotational frequency of a rotary machine. In order to make compact a whole equipment in which a variable-speed fluid coupling and an overdrive gear unit are provided between a driver and a rotary machine, by integrating the output or input impeller of the coupling with one gear of the overdrive unit, a variable-speed fluid coupling comprises an input impeller integrated with an input shaft, an output impeller integrated with an output shaft, an inner casing mounted on the output impeller and covering the input impeller, and a scoop pipe. The output impeller is integrated with a large gear, which is engaged with a small gear so that an overdrive gear unit is constructed. The shaft of the small gear is connected to the impeller of a compressor.

0014<patcit id="pcit0005" dnum="US3065652A"><text>US-A-3,065,652</text></patcit> discloses an electro-hydraulic drive, especially for rail vehicles, and was used as a basis for the preamble of claim 1.

Disclosure of Invention

0015The present invention has been made in view of the above drawbacks. It is therefore an object of the present invention to provide a transmission apparatus which can efficiently transmit a rotational power beyond a transmission limit of a joint unit, and can absorb various kinds of vibrations and impacts, such as pulsation, shock vibration at speed change, and torsion vibration of an output shaft, for thereby enabling an increase in service life and power transmission limit.

0016A transmission apparatus according to the present invention is provided as set forth in claim 1.

0017In a transmission apparatus not according to the present invention, the rotational power which has been input to the transmission apparatus is transmitted to the dividing unit (6) via a single input shaft and is output to two rotating shafts, one of the two rotating shafts is connected to one of two input shafts of the differential planetary gear unit (30), and the other of the two rotating shafts is connected to the other of the two input shafts of the differential planetary gear unit (30) via the fluid coupling (20).

0018<figref idref="f0021">FIGS. 24A through 24D</figref> schematically illustrate the manner in which a power is transmitted from a drive unit A1 to a driven unit A2. For, example, in <figref idref="f0021">FIG. 24A</figref>, a power P from the drive unit A1 is divided by a dividing unit (distribution gears) 6. A power P1, which is one of the divided powers, is transmitted to a differential planetary gear unit A30 via a power line R1. A power P2, which is the other of the divided powers, is transmitted to the differential planetary gear unit A30 via a continuously variable transmission A20 and a power line R2. The power P1 and the power P2 are joined together again in the differential planetary gear unit A30 and then transmitted to the driven unit A2.

0019<figref idref="f0021">FIGS. 24A and 24B</figref> illustrate the manner of power distribution, and <figref idref="f0021">FIGS. 24C and 24D</figref> illustrate the manner of power circulation. In <figref idref="f0021">FIGS. 24A through 24D</figref>, magnitude of the power flow due to action of the differential planetary gear unit A30 is expressed by a width of a white arrow. The power distribution means the manner in which the power from the input side is divided by the distribution gears and the divided powers are transmitted through two paths and then joined together by the differential planetary gear to flow into the output side. The power transmitted through one of two distribution shafts is larger than the power transmitted through the other of the distribution shafts. On the other hand, the power circulation means the manner in which the power from the input side flows only into one of the distribution gears and flows into the output side via the differential planetary gear (hereinafter, a shaft through which the power is transmitted will be referred to as a shaft A). Specifically, as shown in <figref idref="f0021">FIGS. 24C and 24D</figref>, there exists a power flow circulating in the order of the differential planetary gear → the distribution gears → the continuously variable transmission → the differential planetary gear. In this case, the powers flowing through the shaft A are joined together and the joined power becomes larger than the input power. The power flowing through the other shaft becomes small and its flow direction is reversed.

0020<figref idref="f0021">FIGS. 24B and 24C</figref> schematically illustrate the power transmission manner. The magnitude of the power flow of the power line R2 passing through the continuously variable transmissionA20 is smaller than the input power.

0021Specifically, "the rotational power to be transmitted via the joint unit (20) is smaller than the rotational power which has been input to the transmission apparatus" means the manner in which the magnitude of the power flow of the power line R2 passing through the continuously variable transmission A20 is smaller than the input power, as shown in <figref idref="f0021">FIGS. 24B and 24C</figref>. The present invention uses a fluid coupling as the continuously variable transmission. According to the present invention,

0022the fluid coupling comprises a variable-speed fluid coupling. According to the transmission apparatus having such a structure, the rotational power beyond the transmission limit of the joint unit is not input to the joint unit, and hence the rotational power can be transmitted efficiently. Further, the fluid coupling can absorb various kinds of vibrations and impacts, such as pulsation of the input rotational power, shock due to speed change, and torsion vibration of the shaft, thus enabling a smooth transmission of the power.

0023In the above transmission apparatus not according to the present invention, the rotational power which has been input to the transmission apparatus is transmitted to the dividing unit (6) via a single input shaft (15a) and is output to two rotating shafts (4, 9), one (9) of the two rotating shafts (4, 9) is connected to one (13) of two input shafts (13, 5) of the differential planetary gear unit (30), and the other (4) of the two rotating shafts (4, 9) is connected to the other (5) of the two input shafts (13, 5) of the differential planetary gear unit (30) via the fluid coupling (20).

0024With such a structure, even if the power, which is input to the transmission apparatus, exceeds the transmission limit of the joint unit, the input power is divided into two by the dividing unit, so that one of the divided powers, which is below the transmission limit, is distributed to the fluid coupling and the other is directly distributed to the differential planetary gear unit. Accordingly, the transmission apparatus can transmit the power that is beyond the transmission limit of the fluid coupling.

0025In the transmission apparatus according to the present invention, the rotational power which has been input to the transmission apparatus is transmitted to the differential planetary gear unit (30B) via a single input shaft (15b) (of the dividing unit) and is transmitted to two output shafts (13b, 4b) of the differential planetary gear unit (30B), one (a direct-coupling shaft 13b) of the two output shafts of the differential planetary gear unit (30B) is connected to one (9b) of two input shafts of a converging unit (6B), and the other (4b) of the two output shafts of the differential planetary gear unit (30B) is connected to the other (37b) of the two input shafts of the converging unit (6B) via the fluid coupling (20) .

0026According to the transmission apparatus of the present invention having such a structure, the input power is divided into two by the differential planetary gear unit, so that one of the divided powers, which is below the transmission limit, is distributed to the fluid coupling and the other is directly distributed to the dividing unit. Accordingly, the transmission apparatus can transmit the power that is beyond the transmission limit of the fluid coupling.

0027It is preferable that a gear unit (52d, 53d) having a speed-increasing gear and a speed-decreasing gear is provided on at least one of an input shaft (9, 5) and an output shaft (37d) of the differential planetary gear unit.

0028With such a structure, while keeping a rotational speed or a torque that is input to the transmission apparatus constant, the rotational speed or the torque that is output to the driven unit can be freely adjusted to an efficient value.

0029Another transmission apparatus not according to the present invention comprises: a dividing unit to which a rotational power from a drive unit is transmitted; a joint unit; and a first differential planetary gear unit; wherein one rotational power to be transmitted via the joint unit is smaller than the other rotational power, and the joint unit comprises an electric motor and a second differential planetary gear unit.

0030Another transmission apparatus not according to the present invention comprises: at least one of a dividing unit and a first differential planetary gear unit; and a joint unit; wherein a rotational power from a drive unit is divided into at least two rotational powers by the dividing unit or the first differential planetary gear unit, one of the rotational powers is input to the joint unit, the rotational power to be input to the joint unit is smaller than the other of the rotational powers, and the joint unit comprises an electric motor and a second differential planetary gear unit.

0031In the above transmission apparatus not according to the present invention, the rotational power from the drive unit is transmitted to the dividing unit via a single input shaft of the dividing unit and is output from the dividing unit to two rotating shafts, one of the two rotating shafts is connected to one of two input shafts of the first differential planetary gear unit, and the other of the two rotating shafts is connected to the other of the two input shafts of the first differential planetary gear unit.

0032In the above transmission apparatus not according to the present invention, the rotational power from the drive unit is transmitted to a single input shaft of the first differential planetary gear unit, one of two output shafts of the first differential planetary gear unit is connected to one of two input shafts of a converging unit, and the other of the two output shafts of the first differential planetary gear unit is connected to the other of the two input shafts of the converging unit via the second differential planetary gear unit.

0033In the above transmission apparatus not according to the present invention, the second differential planetary gear unit has a single-pinion-type structure in which one planetary gear is arranged in a radial direction and one or more planetary gears are arranged in a circumferential direction in a region between a sun gear and a ring gear, and each of the drive unit, the electric motor, and a load is directly connected to any one of an input shaft, an output shaft, and a speed-change shaft.

0034Accordingly, since the power from the drive unit is transmitted to the load without passing through the joint unit, a capacity of the joint unit can be small even in a case of operating a large machinery. Further, since the joint unit comprises the differential planetary gear unit having no frictional part but having a mechanically coupling structure, the long service life can be achieved and the transmission limit can become sufficiently high.

0035First, there will be illustrated a flow of the rotational power transmitted by a combination of the dividing unit 6, a speed-change device, i.e., the joint unit R, and the differential planetary gear unit G, with reference to <figref idref="f0017 f0018">FIGS. 18 through 21</figref>. The dividing unit 6 is connected to an input shaft I. One of power flows that are output from the dividing unit 6 is input to a shaft R2 of the differential planetary gear unit G through the joint unit R, and the other is input to another shaft R1 of the differential planetary gear unit G. The power flows are then output from an output shaft O.

0036When the power flow, which is represented by a reference sign P, of the input shaft I is divided into P1 and P2 by the dividing unit 6, the power flow of the output shaft is P on the assumption that there is no loss. Magnitude of the power flow is expressed by a width of a white arrow.

0037It is preferable that the power flow passing through the joint unit R is as small as possible, and hence it can be said that the manner shown in <figref idref="f0017">FIGS. 19</figref> and <figref idref="f0018">20</figref> is preferable. Specifically, "the rotational power to be transmitted via the joint unit is smaller than the rotational power which has been input to the transmission apparatus" means the manner in which the magnitude of the power flow of the power line R2 passing through the joint unit R is smaller than the input power, as shown in <figref idref="f0017">FIGS. 19</figref> and <figref idref="f0018">20</figref>.

Brief Description of Drawings

0038<ul id="ul0001" list-style="none" compact="compact"><li><figref idref="f0001">FIG. 1</figref> is a view showing a transmission apparatus not according to the present invention;</li><li><figref idref="f0002">FIG. 2</figref> is a block diagram schematically showing the transmission apparatus in <figref idref="f0001">FIG. 1</figref>;</li><li><figref idref="f0003">FIG. 3</figref> is a view showing a fluid coupling having an operating device (scoop tube) disposed at a power input side;</li><li><figref idref="f0003">FIG. 4</figref> is a view showing the fluid coupling having the operating device (scoop tube) disposed at a power output side;</li><li><figref idref="f0004">FIG. 5</figref> is a view showing a differential planetary gear unit;</li><li><figref idref="f0005">FIG. 6</figref> is a view showing a transmission apparatus according to an embodiment of the present invention;</li><li><figref idref="f0006">FIG. 7</figref> is a view showing a transmission apparatus not according to the present invention;</li><li><figref idref="f0007">FIG. 8</figref> is a view showing a transmission apparatus not according to the present invention;</li><li><figref idref="f0008">FIG. 9</figref> is a view showing a transmission apparatus not according to the present invention;</li><li><figref idref="f0009">FIG. 10</figref> is a view showing a transmission apparatus not according to the present invention;</li><li><figref idref="f0010">FIG. 11</figref> is a view showing a transmission apparatus according to another embodiment of the present invention;</li><li><figref idref="f0011">FIG. 12</figref> is a view illustrating a transmission apparatus not according to the present invention;</li><li><figref idref="f0012">FIG. 13</figref> is a view illustrating a transmission apparatus not according to the present invention;</li><li><figref idref="f0013">FIG. 14</figref> is a view illustrating a transmission apparatus not according to the present invention;</li><li><figref idref="f0014">FIG. 15</figref> is a view illustrating a transmission apparatus not according to the present invention;</li><li><figref idref="f0015">FIG. 16</figref> is a flow chart illustrating an operation of the transmission apparatus shown in <figref idref="f0014">FIG. 15</figref>;</li><li><figref idref="f0016">FIG. 17</figref> is a view illustrating another transmission apparatus;</li><li><figref idref="f0017">FIG. 18</figref> is a view illustrating a power flow of a joint unit distributed by a dividing unit;</li><li><figref idref="f0017">FIG. 19</figref> is a view illustrating another power flow of the joint unit distributed by the dividing unit;</li><li><figref idref="f0018">FIG. 20</figref> is a view illustrating still another power flow of the joint unit distributed by the dividing unit;</li><li><figref idref="f0018">FIG. 21</figref> is a view illustrating still another power flow of the joint unit distributed by the dividing unit;</li><li><figref idref="f0019">FIG. 22</figref> is a block diagram illustrating a relationship between a drive source, a fluid coupling, and a driven unit of a conventional apparatus;</li><li><figref idref="f0020">FIG. 23A</figref> is a view illustrating a conventional transmission apparatus;</li><li><figref idref="f0020">FIG. 23B</figref> is a view showing a power-dividing unit, a continuously variable transmission, and a differential planetary gear unit of a conventionally proposed transmission apparatus; and</li><li><figref idref="f0021">FIGS. 24A through 24D</figref> are schematic views illustrating the manner in which a power is transmitted from a drive unit to a driven unit.</li></ul>

Best Mode for Carrying Out the Invention

0039<figref idref="f0001">FIG. 1</figref> is a schematic view showing a detailed structure of a transmission apparatus, and <figref idref="f0002">FIG. 2</figref> is a block diagram schematically showing the transmission apparatus. Those parts which are denoted by the same reference numerals as those of the conventional apparatus shown <figref idref="f0020">FIG. 23</figref> have identical structure and function.

0040In <figref idref="f0001">FIGS. 1</figref> and <figref idref="f0002">2</figref>, a transmission apparatus 15 is disposed between a motor A1 (expressed as a drive unit A1 in <figref idref="f0001">FIG. 1</figref>) serving as a drive source and a fluid machinery A2 (expressed as a rotary machine A2 in <figref idref="f0001">FIG. 1</figref>) serving as a driven unit. The transmission apparatus 15 is coupled to the motor A1 and the fluid machinery A2 via an input-side clutch 3 and an output-side clutch 39.

0041The transmission apparatus 15 comprises a power-dividing unit 6, a fluid coupling 20 for speed change, and a differential planetary gear unit 30, each of which serves as an essential part thereof.

0042The power-dividing unit 6 divides a rotational power of a rotating input shaft 15a connected to the input-side clutch 3 into two and distributes the divided rotational powers to a rotating shaft 4, which is directly connected to the rotating input shaft 15a, and to a rotating shaft 9 via gears 7 and 8. A power line via the rotating shaft 4 serves as a power line R1, and a power line via the rotating shaft 9 serves as a power line R2. There are two cases in the direction of the power transmission of the power line R1: One is that the power is transmitted from the rotating shaft 4 to the rotating shaft 5 via the fluid coupling 20, and the other is that the power is transmitted from the rotating shaft 5 to the rotating shaft 4 via the fluid coupling 20.

0043In the latter case, the fluid coupling 20 comprises an operating device 22, a drive pump 26, and a driven turbine 24, and is constructed so as to transmit the power from the rotating shaft 5 to the rotating shaft 4.

0044The differential planetary gear unit 30 comprises a sun gear 31, pinion gears 33, and a ring gear 35, as with a known structure. The sun gear 31 which is directly connected to the rotating shaft 5, and a carrier 13 which couples the rotating shaft 9 to the pinion gears 33 via a gear 12 serve as input shafts, respectively, and the ring gear 35 serves as an output shaft. The ring gear 35 is connected to the fluid machinery A2 via a rotating shaft 37 and the output-side clutch 39.

0045<figref idref="f0003">FIG. 3</figref> shows the fluid coupling 20 having a structure in which a power aspect (i.e., a rotational speed and a torque) to be transmitted to the rotating shaft 4 directly connected to the turbine 24 is operated by the operating device 22 which controls a rotational speed of the pump 26 directly connected to the rotating shaft 5. <figref idref="f0003">FIG. 4</figref> shows a structure in which the power aspect to be transmitted to the rotating shaft 5 is operated by the operating device 22 which controls a circulating flow between the pump 26, which is directly connected to the rotating shaft 4, and the turbine 24.

0046The fluid coupling 20 shown in <figref idref="f0003">FIG. 3</figref> is the type that is used in the transmission apparatus 15 of <figref idref="f0001">Fig. 1</figref>.

0047<figref idref="f0004">FIG. 5</figref> shows a structure of the differential planetary gear unit 30. The sun gear 31 connected to the rotating shaft 5 serves as the input shaft, and the carrier 13 rotatably supporting the pinion gears 33 and connected to the rotating shaft 9 also serves as the input shaft. The ring gear 35 serves as the output shaft. It is known that the differential planetary gear unit has six permutations of input-output patterns that are made by a combination of the sun gear 31, the carrier 13, and the ring gear 35. Specifically, the number of permutations of the elements comprising the sun gear 31, the carrier 13, and the ring gear 35, two input shafts (i.e., the direct-coupling shaft 9 (see <figref idref="f0002">FIG. 2</figref>) without passing through the speed-change device and the speed-change shaft 5 passing through the speed-change device), and one output shaft 37 of the differential planetary gear unit is six given by 3!.

0048Operation of the transmission apparatus 15 having the above-mentioned structure will be described below.

0049First, a rotational power having a torque Ti and a rotational speed ωi is transmitted from the motor A1 serving as a drive source to the rotating input shaft 15a of the transmission apparatus 15 via the input-side clutch 3. The rotating input shaft 15a transmits the rotational power to the power-dividing unit 6. The power-dividing unit 6 distributes the rotational power to the rotating shaft 4 of the power line R1 and the rotating shaft 9 of the power line R2. At this time, the distribution of the rotational power to the rotating shaft 4 is limited to such a degree that a torque is below a transmission limit defined by an absorption capability of the fluid coupling 20 while a rotational speed is ωi. The rotational power distributed to the rotating shaft 9 has the rotational speed ωi and a residual torque if the power-dividing unit 6a has a gear ratio of 1. It is preferable that the torque to be distributed to the fluid coupling 20 is selected such that an efficient transmission is achieved while the torque is kept below the transmission limit.

0050The rotational power of the rotating shaft 9 is transmitted to the carrier 13 via the gear 12. On the other hand, the rotational power of the rotating shaft 4 is changed in speed and torque by the fluid coupling 20 and transmitted to the sun gear 31 of the differential planetary gear unit 30.

0051The rotational powers transmitted to the carrier 13 and the sun gear 31 are transmitted from the ring gear 35 to the fluid machinery A2 via the rotating shaft 37 and the output-side clutch 39. At this time, the rotational power transmitted to the fluid machinery A2 has a rotational speed ωo and a torque To. Assuming that there is no power transmission loss in the transmission apparatus 15, the following relation holds: ω i×Ti=ωo×To

0052In this manner, the rotational power from the motor A1 is divided into two and distributed to the power line R1 passing through the fluid coupling 20 and the branched power line R2, and the divided rotational powers are joined together again by the differential planetary gear unit 30, so that the transmission apparatus 15 transmits the rotational power that is beyond the rotational power limit of the fluid coupling 20.

0053<figref idref="f0005">FIG. 6</figref> shows an embodiment of the present invention. Those parts which are di fferent from those shown in <figref idref="f0001">FIGS. 1</figref> and <figref idref="f0002">2</figref> will be mainly described below. Those parts which are denoted by the same reference numerals as those shown <figref idref="f0001">FIG. 1</figref> have identical structure and function.

0054In <figref idref="f0005">FIG. 6</figref>, a transmission apparatus 15B is disposed between a motor A1 (expressed as a drive unit A1 in <figref idref="f0005">FIG. 6</figref>) serving as a drive source and a fluid machinery A2 (expressed as a rotary machine A2 in <figref idref="f0005">FIG. 6</figref>) serving as a driven unit. The transmission apparatus 15B is coupled to the motor A1 and the fluid machinery A2 via an input-side clutch 3 and an output-side clutch 39.

0055The transmission apparatus 15B comprises a differential planetary gear unit 30B, a fluid coupling 20 for speed change, and a power converging unit 6B, each of which serves as an essential part thereof.

0056The differential planetary gear unit 30B comprises a sun gear 31b, pinion gears 33b, and a ring gear 35b, as with a known structure. The ring gear 35b directly connected to a rotating shaft 15b serves as an input shaft, and a carrier 13b connected to a rotating shaft 9b and a rotating shaft 4b connected to the sun gear 31b serve as output shafts, respectively.

0057The fluid coupling 20 comprises an operating device 22, a drive pump 26, and a driven turbine 24, and is constructed so as to transmit the power from the rotating shaft 4b to the rotating shaft 37b.

0058The power converging unit 6B has a converging function instead of a dividing function of the above-mentioned power-dividing unit 6. The power converging unit 6B serves to converge the rotational power from the rotating shaft 9b and the rotational power from the fluid coupling 20 on the rotating shaft 37b.

0059A power line via the rotating shaft 4b serves as a power line Rb1, and a power line via the rotating shaft 9b serves as a power line Rb2.

0060Operation of the transmission apparatus 15B having the above-mentioned structure will be described below.

0061First, a rotational power having a torque Ti and a rotational speed ωi is transmitted from the motor A1 serving as a drive source to the rotating input shaft 15b and the ring gear 35b of the differential planetary gear unit 30B via the input-side clutch 3. The rotational power transmitted to the ring gear 35b is divided into two and distributed to the carrier 13b and the sun gear 31b. The divided rotational powers are transmitted to the rotating shaft 9b of the power line Rb2 and the rotating shaft 4b of the power line Rb1. The rotational power transmitted to the rotating shaft 4b is changed in speed and torque by the fluid coupling 20 and transmitted to the rotating shaft 37b serving as an input shaft of the power converging unit 6B.

0062On the other hand, the rotational power from the rotating shaft 9b is also transmitted to the rotating shaft 37b where the power line Rb2 and the power line Rb1 are joined together and transmitted to the fluid machinery A2 via the output-side clutch 39. At this time, the rotational power transmitted to the fluid machinery A2 has a rotational speed ω o and a torque To. Assuming that there is no power transmission loss in the transmission apparatus 15B, the following relation holds: ω i×Ti=ωo×To

0063In this manner, the rotational power from the motor A1 is divided into two and distributed to the power line Rb1 passing through the fluid coupling 20 and the branched power line Rb2, and the divided rotational powers are joined together again by the power converging unit 6B, so that the transmission apparatus 15B transmits the rotational power beyond the rotational power limit of the fluid coupling 20.

0064<figref idref="f0006">FIG. 7</figref> shows another transmission apparatus. Those parts which are different from those shown in <figref idref="f0001">FIG. 1</figref> will be mainly described below. Those parts which are denoted by the same reference numerals as those shown <figref idref="f0001">FIG. 1</figref> have identical structure and function.

0065In <figref idref="f0006">FIG. 7</figref>, a transmission apparatus 15C is disposedbetween a motor A1 (expressed as a drive unit A1 in <figref idref="f0006">FIG. 7</figref>) serving as a drive source and a fluid machinery A2 (expressed as a rotary machine A2 in <figref idref="f0006">FIG. 7</figref>) serving as a driven unit. The transmission apparatus 15C is coupled to the motor A1 and the fluid machinery A2 via an input-side clutch 3 and an output-side clutch 39.

0066The transmission apparatus 15C comprises a power-dividing unit 6, a fluid coupling 20 for speed change, and a differential planetary gear unit 30, each of which serves as an essential part thereof.

0067The power-dividing unit 6 distributes a rotational power of a rotating input shaft 15c connected to the input-side clutch 3 to a rotating shaft 9c, which is connected to the rotating input shaft 15c, and to a rotating shaft 4c via gears 7 and 8. A power line via the rotating shaft 4c serves as a power line Rc1, and a power line via the rotating shaft 9c serves as a power line Rc2.

0068The fluid coupling 20 is constructed so as to transmit the power from the rotating shaft 4c to the rotating shaft 5c.

0069The differential planetary gear unit 30 comprises a sun gear 31, pinion gears 33, and a ring gear 35, as with a known structure. The sun gear 31 connected to the rotating shaft 9c, and a carrier 13c which couples the rotating shaft 5c to the pinion gears 33 via the gear 12c serve as input shafts, respectively, and the ring gear 35 serves as an output shaft. The ring gear 35 is connected to the fluid machinery A2 via the output-side clutch 39.

0070Operation of the transmission apparatus 15C having the above-mentioned structure will be described below.

0071First, a rotational power having a torque Ti and a rotational speed ωi is transmitted from the motor A1 serving as a drive source to the rotating input shaft 15c of the transmission apparatus 15C via the input-side clutch 3. The rotating input shaft 15c transmits the rotational power to the power-dividing unit 6. The power-dividing unit 6 distributes the rotational power to the rotating shaft 4c of the power line Rc1 and the rotating shaft 9c of the power line Rc2. At this time, the distribution of the rotational power to the rotating shaft 4c is limited to such a degree that a torque is below a transmission limit defined by an absorption capability of the fluid coupling 20 while a rotational speed is ωi. The rotational power distributed to the rotating shaft 9c has the rotational speed wi and a residual torque. It is preferable that the torque to be distributed to the fluid coupling 20 is selected such that an efficient transmission is achieved while the torque is kept below the transmission limit.

0072The rotational power of the rotating shaft 9c is transmitted to the sun gear 31 of the differential planetary gear unit 30. On the other hand, the rotational power of the rotating shaft 4c is changed in speed and torque by the fluid coupling 20 and transmitted to the carrier 13c via the gear 12c.

0073The rotational powers transmitted to the sun gear 31 and the carrier 13c are transmitted from the ring gear 35 to the fluid machinery A2 via the rotating shaft 37 and the output-side clutch 39. At this time, the rotational power transmitted to the fluid machinery A2 has a rotational speed ωo and a torque To. Assuming that there is no power transmission loss in the transmission apparatus 15C, the following relation holds: ω i×Ti=ωo×To

0074In this manner, the rotational power from the motor A1 is divided into two and distributed to the power line Rc1 passing through the fluid coupling 20 and the branched power line Rc2, and the divided rotational powers are joined together again by the differential planetary gear unit 30, so that the transmission apparatus 15C transmits the rotational power beyond the rotational power limit of the fluid coupling 20.

0075<figref idref="f0007">FIG. 8</figref> shows another transmission apparatus. Those parts which are different from those shown in <figref idref="f0001">FIGS. 1</figref> and <figref idref="f0002">2</figref> will be mainly described below. Those parts which are denoted by the same reference numerals as those shown <figref idref="f0001">FIGS. 1</figref> and <figref idref="f0002">2</figref> have identical structure and function.

0076In <figref idref="f0007">FIG. 8</figref>, a transmission apparatus 15D is disposedbetween a motor A1 (expressed as a drive unit A1 in <figref idref="f0007">FIG. 8</figref>) serving as a drive source and a fluid machinery A2 (expressed as a rotary machine A2 in <figref idref="f0007">FIG. 8</figref>) serving as a driven unit. The transmission apparatus 15D is coupled to the motor A1 and the fluid machinery A2 via an input-side clutch 3 and an output-side clutch 39.

0077The transmission apparatus 15D comprises a power-dividing unit (distribution gears) 6, a fluid coupling 20 for speed change, gear units 52d and 53d, and a differential planetary gear unit 30, each of which serves as an essential part thereof.

0078The power-dividing unit 6 is constructed so as to distribute a rotational power of a rotating input shaft 15d connected to the input-side clutch 3 to a rotating shaft 4, which is directly connected to the rotating input shaft 15d, and a separated rotating shaft 9. A power line via the rotating shaft 4 serves as a power line Rd1, and a power line via the rotating shaft 9 serves as a power line Rd2.

0079The fluid coupling 20 is constructed so as to transmit the power from the rotating shaft 4 to the rotating shaft 5.

0080The gear unit 52d for increasing or decreasing a rotational speed is provided on the rotating shaft 9 and is coupled to the differential planetary gear unit 30 via a rotating shaft 9d. The gear unit 53d for increasing or decreasing a rotational speed is provided on the rotating shaft 4 and is coupled to the differential planetary gear unit 30 via a rotating shaft 5d.

0081Change gear ratios of the gear units 52d and 53d are set such that a rotational speed to be input to the fluid machinery A2 via the differential planetary gear unit 30 allows the fluid machinery A2 to be operated at a maximum efficiency.

0082The differential planetary gear unit 30 is constructed such that the rotating shaft 9d and the rotating shaft 5d serve as the input shafts and the rotational powers of these input shafts are converged and transmitted to the rotating shaft 37d. The rotating shaft 37d is connected to the fluid machinery A2 via the output-side clutch 39.

0083Other components are the same as those of <figref idref="f0001">Fig.1</figref>.

0084Operation of the transmission apparatus 15D having the above-mentioned structure will be described below.

0085First, a rotational power having a torque Ti and a rotational speed ωi is transmitted from the motor A1 serving as a drive source to the rotating input shaft 15d of the transmission apparatus 15D via the input-side clutch 3. The rotating input shaft 15d transmits the rotational power to the power-dividing unit 6. The power-dividing unit 6 distributes the rotational power to the rotating shaft 4 of the power line Rd1 and the rotating shaft 9 of the power line Rd2. At this time, the distribution of the rotational power to the rotating shaft 4 is limited to such a degree that a torque is below a transmission limit defined by an absorption capability of the fluid coupling 20 while a rotational speed is ωi. The rotational power distributed to the rotating shaft 9 has the rotational speed ωi and a residual torque if the power-dividing unit 6 has a gear ratio of 1. It is preferable that the torque to be distributed to the fluid coupling 20 is selected such that an efficient transmission is achieved while the torque is kept below the transmission limit.

0086The rotational power of the rotating shaft 9 is increased or decreased in speed by the gear unit 52d and transmitted to the differential planetary gear unit 30. On the other hand, the rotational power of the rotating shaft 4 is changed in speed and torque by the fluid coupling 20, and is further increased or decreased in speed by the gear unit 53d and transmitted to the differential planetary gear unit 30.

0087In the differential planetary gear unit 30, the rotating shaft 9d and the rotating shaft 5d serve as the input shafts, and the rotational powers of these input shafts are converged and transmitted to the rotating shaft 37d.

0088The rotational power is transmitted from the rotating shaft 37d to the fluid machinery A2 via the output-side clutch 39. At this time, the rotational power has a rotational speed ωo and a torque To. Assuming that there is no power transmission loss in the transmission apparatus 15D, the following relation holds: ωi×Ti=ωo×To

0089In this manner, the rotational power from the motor A1 is divided into two and distributed to the power line Rd1 passing through the fluid coupling 20 and the branched power line Rd2. The rotational speeds of the power line Rd1 and the power line Rd2 are changed such that the rotational speed to be input to the fluid machinery A2 allows the fluid machinery A2 to be operated at a maximum efficiency. The power line Rd1 and the power line Rd2 are joined together again by the differential planetary gear unit 30. Thus, the transmission apparatus 15D transmits the rotational power beyond the rotational power limit of the fluid coupling 20.

0090<figref idref="f0008">FIG. 9</figref> shows another transmission apparatus. Those parts which are different from those shown in <figref idref="f0001">FIGS. 1</figref> and <figref idref="f0002">2</figref> will be mainly described below. Those parts which are denoted by the same reference numerals as those shown <figref idref="f0001">FIGS. 1</figref> and <figref idref="f0002">2</figref> have identical structure and function.

0091In <figref idref="f0008">FIG. 9</figref>, a transmission apparatus 15E is disposedbetween a motor A1 (expressed as a drive unit A1 in <figref idref="f0008">FIG. 9</figref>) serving as a drive source and a fluid machinery A2 (expressed as a rotary machine A2 in <figref idref="f0008">FIG. 9</figref>) serving as a driven unit. The transmission apparatus 15E is coupled to the motor A1 and the fluid machinery A2 via an input-side clutch 3 and an output-side clutch 39.

0092The transmission apparatus 15E comprises a power-dividing unit (distribution gears) 6, a fluid coupling 20 for speed change, a gear unit 54e, and a differential planetary gear unit 30, each of which serves as an essential part thereof.

0093The power-dividing unit 6 distributes a rotational power of a rotating input shaft 15a connected to the input-side clutch 3 to a rotating shaft 4, which is directly connected to the rotating input shaft 15a, and a separated rotating shaft 9. A power line via the rotating shaft 4 serves as a power line Re1, and a power line via the rotating shaft 9 serves as a power line Re2.

0094The fluid coupling 20 is constructed so as to transmit the power from the rotating shaft 4 to the rotating shaft 5.

0095The rotating shaft 9 is connected to the differential planetary gear unit 30, and the rotating shaft 4 is connected to the differential planetary gear unit 30 via the rotating shaft 5.

0096The differential planetary gear unit 30 is constructed such that the rotating shaft 9 and the rotating shaft 5 serve as the input shafts and the rotational powers of these input shafts are converged and transmitted to the rotating shaft 37. The rotating shaft 37 is connected to the fluid machinery A2 via the gear unit 54e and the output-side clutch 39. A change gear ratio of the gear unit 54e is set such that the rotational speed to be input to the fluid machinery A2 allows the fluid machinery A2 to be operated at a maximum efficiency.

0097Other components are the same as those of <figref idref="f0001">Fig. 1</figref>.

0098Operation of the transmission apparatus 15E having the above-mentioned structure will be described below.

0099First, a rotational power having a torque Ti and a rotational speed ωi is transmitted from the motor A1 serving as a drive source to the rotating input shaft 15a of the transmission apparatus 15E via the input-side clutch 3. The rotating input shaft 15a transmits the rotational power to the power-dividing unit 6. The power-dividing unit 6 distributes the rotational power to the rotating shaft 4 of the power line Re1 and the rotating shaft 9 of the power line Re2. At this time, the distribution of the rotational power to the rotating shaft 4 is limited to such a degree that a torque is below a transmission limit defined by an absorption capability of the fluid coupling 20 while a rotational speed is ωi. The rotational power distributed to the rotating shaft 9 has the rotational speed ω i and a residual torque if the power-dividing unit 6 has a gear ratio of 1. It is preferable that the torque to be distributed to the fluid coupling 20 is selected such that an efficient transmission is achieved while the torque is kept below the transmission limit.

0100The rotational power of the rotating shaft 9 is transmitted to the differential planetary gear unit 30. The rotational power of the rotating shaft 4 is changed in speed and torque by the fluid coupling 20 and transmitted to the differential planetary gear unit 30.

0101In the differential planetary gear unit 30, the rotating shaft 9 and the rotating shaft 5 serve as the input shafts, and the rotational powers of these input shafts are converged and transmitted to the rotating shaft 37. The rotational power of the rotating shaft 37 is changed in speed by the gear unit 54e so as to allow the fluid init A2 to be operated at a maximum efficiency, and is transmitted to the fluid machinery A2 via the output-side clutch 39. At this time, the rotational power transmitted to the fluid machinery A2 has a rotational speed ωo and a torque To. Assuming that there is no power transmission loss in the transmission apparatus 15E, the following relation holds: ωi×Ti=ωo×To

0102In this manner, the rotational power from the motor A1 is divided into two and distributed to the power line Re1 passing through the fluid coupling 20 and the branched power line Re2, and the divided rotational powers are joined together again by the differential planetary gear unit 30. Thus, the transmission apparatus 15E transmits the rotational power beyond the rotational power limit of the fluid coupling 20. Further, the rotational speed to be input to the fluid machinery A2 is changed by the gear unit 54e so that the fluid machinery A2 is operated at a maximum efficiency.

0103<figref idref="f0009">FIG. 10</figref> shows another transmission apparatus. Those parts which are different from those shown in <figref idref="f0001">FIGS. 1</figref> and <figref idref="f0002">2</figref> will be mainly described below. Those parts which are denoted by the same reference numerals as those shown <figref idref="f0001">FIGS. 1</figref> and <figref idref="f0002">2</figref> have identical structure and function.

0104In <figref idref="f0009">FIG. 10</figref>, a transmission apparatus 15F is disposed between a motor A1 serving as a drive source and a fluid machinery A2 serving as a driven unit. The transmission apparatus 15F is coupled to the motor A1 and the fluid machinery A2 via an input-side clutch 3 and an output-side clutch 39.

0105The transmission apparatus 15F comprises a power-dividing unit (distributiongears) 6, afluidcoupling20forspeedchange, gear units 51f, 53f and 55f, and a differential planetary gear unit 30, each of which serves as an essential part thereof.

0106The power-dividing unit 6 is constructed so as to distribute a rotational power of a rotating input shaft 15a connected to the input-side clutch 3 to a rotating shaft 4, which is directly connected to the rotating input shaft 15a, and a separated rotating shaft 9. A power line via the rotating shaft 4 serves as a power line Rf1, and a power line via the rotating shaft 9 serves as a power line Rf2.

0107The fluid coupling 20 is constructed so as to transmit the power from the rotating shaft 4 to the rotating shaft 5.

0108The gear unit 51 f for increasing or decreasing a rotational speed is provided on the rotating shaft 9. The rotational power, which is distributed to the rotating shaft 9 by the distribution gears 6, is increased or decreased in speed by the gear unit 51f, and is further transmitted to the differential planetary gear unit 30 via a rotating shaft 9f. The gear unit 53f for increasing or decreasing a rotational speed is provided on the rotating shaft 5. The rotational power, which is distributed to the rotating shaft 4 by the distribution gears 6, is increased or decreased in speed by the gear unit 53f, and is further transmitted to the differential planetary gear unit 30 via a rotating shaft 5f.

0109The differential planetary gear unit 30 is constructed such that the rotating shaft 9f and the rotating shaft 5f serve as the input shafts and the rotational powers of these input shafts are converged and transmitted to the rotating shaft 37. The rotating shaft 37 is connected to the fluid machinery A2 via the gear unit 55f for increasing or decreasing the rotational speed and the clutch 39.

0110Change gear ratios of the gear units 51f, 53f and 55f are set such that the fluid machinery A2 is operated at a maximum efficiency.

0111Other components are the same as those of <figref idref="f0001">Fig. 1</figref>.

0112Operation of the transmission apparatus 15F having the above-mentioned structure will be described below.

0113First, a rotational power having a torque Ti and a rotational speed ωi is transmitted from the motor A1 serving as a drive source to the rotating input shaft 15a of the transmission apparatus 15F via the input-side clutch 3. The rotating input shaft 15a transmits the rotational power to the power-dividing unit 6. The power-dividing unit 6 distributes the rotational power to the rotating shaft 4 of the power line Rf1 and the rotating shaft 9 of the power line Rf2. At this time, the distribution of the rotational power to the rotating shaft 4 is limited to such a degree that a torque is below a transmission limit defined by an absorption capability of the fluid coupling 20 while a rotational speed is ω i. The rotational power distributed to the rotating shaft 9 has the rotational speed ωi and a residual torque if the power-dividing unit 6 has a gear ratio of 1. It is preferable that the torque to be distributed to the fluid coupling 20 is selected such that an efficient transmission is achieved while the torque is kept below the transmission limit.

0114The rotational power of the rotating shaft 9 is increased or decreased in speed by the gear unit 51f and transmitted to the differential planetary gear unit 30. On the other hand, the rotational power of the rotating shaft 4 is changed in speed and torque by the fluid coupling 20, and is further increased or decreased in speed by the gear unit 53f and transmitted to the differential planetary gear unit 30.

0115In the differential planetary gear unit 30, the rotating shaft 9f and the rotating shaft 5f serve as the input shafts, and the rotational powers of these input shafts are converged and transmitted to the rotating shaft 37.

0116The rotational power of the rotating shaft 37 is changed in speed by the gear unit 55f so as to allow the fluid init A2 to be operated at a maximum efficiency, and is transmitted to the fluid machinery A2 via the output-side clutch 39. At this time, the rotational power has a rotational speed ωo and a torque To. Assuming that there is no power transmission loss in the transmission apparatus 15F, the following relation holds: ωi×Ti =ωo×To

0117In this manner, the rotational power from the motor A1 is divided into two and distributed to the power line Rf1 passing through the fluid coupling 20 and the branched power line Rf2, and the divided rotational powers are joined together again by the differential planetary gear unit 30, so that the transmission apparatus 15F transmits the rotational power beyond the rotational power limit of the fluid coupling 20. Further, the rotational speed to be input to the fluid machinery A2 is changed by the gear units 51f, 53f and 55f so that the fluid machinery A2 is operated at a maximum efficiency.

0118<figref idref="f0010">FIG. 11</figref> shows another embodiment of the present invention. Those parts which are different from those shown in <figref idref="f0001">FIGS. 1</figref> and <figref idref="f0002">2</figref> will be mainly described below. Those parts which are denoted by the same reference numerals as those shown <figref idref="f0001">FIGS. 1</figref> and <figref idref="f0002">2</figref> have identical structure and function.

0119In <figref idref="f0010">FIG. 11</figref>, a transmission apparatus 15G is disposed between a motor A1 (expressed as a drive unit A1 in <figref idref="f0010">FIG. 11</figref>) serving as a drive source and a fluid machinery A2 (expressed as a rotary machine A2 in <figref idref="f0010">FIG. 11</figref>) serving as a driven unit. The transmission apparatus 15G is coupled to the motor A1 and the fluid machinery A2 via an input-side clutch 3 and an output-side clutch 39.

0120The transmission apparatus 15G comprises a differential planetary gear unit 30, a fluid coupling 20 for speed change, gear units 51g, 52g and 53g, and a power converging unit (joining gears) 6B, each of which serves as an essential part thereof.

0121The gear unit 51g for increasing or decreasing a rotational speed is provided on the rotating input shaft 15a connected to the input-side clutch 3. The rotational power, which is transmitted to the rotating input shaft 15a, is increased or decreased in speed by the gear unit 51g, and is further transmitted to the differential planetary gear unit 30 via a rotating shaft 4g.

0122The differential planetary gear unit 30 is constructed so as to distribute the rotational power of the rotating shaft 4g to a rotating shaft 8g and a rotating shaft 5g.

0123The gear unit 52g for increasing or decreasing a rotational speed is provided on the rotating shaft 8g. The rotational power, which is distributed to the rotating shaft 8g by the differential planetary gear unit 30, is increased or decreased in speed by the gear unit 52g, and is further transmitted to one of input shafts of the power converging unit 6B via a rotating shaft 9g. The gear unit 53g for increasing or decreasing a rotational speed is provided on the rotating shaft 5g, and is coupled to the fluid coupling 20 via a rotating shaft 6g. The fluid coupling 20 is connected to the other of the input shafts of the power converging unit 6B via a rotating shaft 37g.

0124A power line via the fluid coupling 20 serves as a power line Rg1, and a power line via the rotating shaft 9g serves as a power line Rg2.

0125The power converging unit 6B is constructed so as to converge the rotational powers from the rotating shaft 9g and the rotating shaft 37g and transmit the converged rotational power to the output-side clutch 39.

0126Change gear ratios of the gear units 51g, 52g and 53g are set such that the rotational speed to be input to the fluid machinery A2 allows the fluid machinery A2 to be operated at a maximum efficiency.

0127Other components are the same as those of <figref idref="f0001">Fig. 1</figref> or <figref idref="f0005">6</figref>.

0128Operation of the transmission apparatus 15G having the above-mentioned structure will be described below.

0129First, a rotational power having a torque Ti and a rotational speed ωi is transmitted from the motor A1 serving as a drive source to the rotating input shaft 15a of the transmission apparatus 15G via the input-side clutch 3. The rotational speed of the rotating input shaft 15a is increased or decreased by the gear unit 51g, and the rotational power transmitted to the rotating input shaft 15a is transmitted to the differential planetary gear unit 30 via the gear unit 51g.

0130The differential planetary gear unit 30 distributes the rotational power of the rotating input shaft 15a to the rotating shaft 5g of the power line Rg1 and the rotating shaft 8g of the power line Rg2. At this time, a torque of the rotational power to be distributed to the rotating shaft 5g is limited to a level below a transmission limit defined by an absorption capability of the fluid coupling 20, and a residual torque is distributed to the rotating shaft 8g. It is preferable that the rotational power to be distributed to the fluid coupling 20 is adjusted by the gear unit 53g such that an efficient transmission is achieved while the rotational speed and the torque are kept below the transmission limit.

0131The rotating shaft 8g transmits the torque to the power converging unit 6B via the gear unit 52g and the rotating shaft 9g, and the rotating shaft 5g transmits the torque to the power converging unit 6B via the gear unit 53g, the rotating shaft 6g, and the fluid coupling 20.

0132In the power converging unit 6B, the rotational powers of the rotating shaft 9g and the rotating shaft 37g are converged into one rotational power, which is transmitted to the fluid machinery A2 via the output-side clutch 39. At this time, the rotational power has a rotational speed ωo and a torque To. Assuming that there is no power transmission loss in the transmission apparatus 15G, the following relation holds: ω i×Ti=ωo×To

0133In this manner, the rotational power from the motor A1 is changed in speed by the gear unit 51g so as to meet a performance of the differential planetary gear unit 30, and is divided into two and distributed to the power line Rg1 passing through the fluid coupling 20 and the power line Rg2. The power line Rg1 and the power line Rg2 are converged again by the power converging unit 6B. Thus, the transmission apparatus 15G transmits the rotational power beyond the rotational power limit of the fluid coupling 20. Further, the rotational speed to be input to the fluid machinery A2 is changed by the gear units 52g and 53g so as to allow the fluid machinery A2 to be operated at a maximum efficiency.

0134Advantages of the transmission apparatus according to the present invention shown in <figref idref="f0005">FIGS. 6</figref> and <figref idref="f0010">11</figref> are listed below. <ol id="ol0001" compact="compact"><li>(1) The rotational power beyond the transmission limit of the joint unit is not input to the joint unit, and hence the rotational power can be transmitted efficiently. Further, the fluid coupling can absorb various kinds of vibrations and impacts such as pulsation of the input rotational power, shock due to speed change, and torsion vibration of the shaft, thus enabling a smooth transmission of the power.</li><li>(2) The input power is divided into two by the differential planetary gear unit, so that one of the divided powers, which is below the transmission limit, is distributed to the fluid coupling and the other is directly distributed to the dividing unit. Accordingly, the transmission apparatus can transmit the power beyond the transmission limit of the fluid coupling.</li><li>(3) The gear unit is provided on the power line so that the rotational speed to be transmitted to the fluid machinery is changed while keeping the rotational power of the drive source constant. With this structure, an efficiency of the fluid machinery can be optimized.</li></ol>

0135<figref idref="f0011">FIG. 12</figref> shows another transmission apparatus. In <figref idref="f0011">FIG. 12</figref>, an output shaft 60 of a drive unit, e.g., an electric motor M, is coupled to a first gear 61 constituting a dividing unit 6. The first gear 61 is in mesh with a second gear 62 of the dividing unit 6.

0136The dividing unit 6 has a first output shaft 63 serving as a rotating shaft of the first gear 61. This first output shaft 63 is connected to a sun gear 64 of a second differential planetary gear unit P2. A carrier 66 of planetary gears 65 of the differential planetary gear unit P2 is coupled to a gear 67 meshing with a gear 68 that is coupled to an output shaft 69 of a small-capacity variable-speed motor 70. A ring gear 71 of the second differential planetary gear unit P2 is connected to an output shaft 72.

0137In this example shown in <figref idref="f0011">FIG. 12</figref>, the output shaft 60 of the drive unit M is connected to the sun gear 64 via the output shaft 63, and a rotational power of the variable-speed motor 70 is transmitted to the planetary gears 65. Although the ring gear 71 is connected to the output shaft 72, connection arrangement can be made freely. For example, the output shaft 63 may be connected to the ring gear 71 or the carrier 66, or the output shaft 69 of the variable-speed motor 70 may be connected to the sun gear 64 or the ring gear 71. Further, the output shaft 72 may be connected to the sun gear 64 or the carrier 66.

0138Specifically, the connection arrangement of three rotating parts of the differential planetary gear unit can be selected freely. Therefore, in the case of not specifying the gear, the three rotating parts will be referred to as a first rotating element, a second rotating element, and a third rotating element.

0139An output shaft 73 of the second gear 62 of the dividing unit 6 is connected to a gear 74, and this gear 74 meshes with a gear 75 coupled to the carrier 77 of the planetary gears 76 of a first differential planetary gear unit P1.

0140The output shaft 72 of the second differential planetary gear unit P2 is connected to the sun gear 78 of the first differential planetary gear unit P1, and a ring gear 79 of the first differential planetary gear unit P1 is coupled to a load L such as a fluid machinery via an output shaft 80.

0141Therefore, a rotational power of the output shaft 60 of the drive unit M is distributed to the output shaft 63 of the first gear 61 and the output shaft 73 of the second gear 62 by the dividing unit 6. The planetary gears 65 of the second differential planetary gear unit P2 are rotated by the rotation of the variable-speed motor 70, and hence the rotational speed of the ring gear 71 is changed according to the rotational speed of the planetary gears 65. In this manner, as the rotational speedof the output shaft 72 of the second differential planetary gear unit P2 is changed, the rotational speed of the sun gear 78 of the first differential planetary gear unit P1 is also changed. As a result, the rotational speed of the output shaft 80 of the first differential planetary gear unit P1 can be changed, and hence the rotational speed of the load L can be controlled.

0142<figref idref="f0012">FIG. 13</figref> shows another transmission apparatus. An output shaft 60 of a drive unit M is connected to a first rotating element of a first differential planetary gear unit P1, and is also connected to a second rotating element, which mainly transmits a power, of the first differential planetary gear unit P1. A first output shaft 81 is a direct-coupling shaft and is connected to a second gear 82 of a converging unit 6B. A second output shaft 83, which is connected to a third rotating element of the first differential planetary gear unit P1, is a speed-change shaft and is connected to a first rotating element of the second differential planetary gear unit P2.

0143A second rotating element of this second differential planetary gear unit P2 is connected to an output shaft 69 serving as a motor shaft of a small-capacity variable-speed motor 70. Further, a third rotating element of the second differential planetary gear unit P2 is connected to a first gear 84 meshing with the second gear 82 of the converging unit 6B. An output shaft 85 of the converging unit 6B, i.e., a shaft of the first gear 84, is connected to the load L.

0144In this apparatus shown in <figref idref="f0012">FIG. 13</figref> also, most of the rotational power of the drive unit M is transmitted from the output shaft 81, which serves as a direct-coupling shaft connected to the second rotating element of the first differential planetary gear unit P1, to the load L via the dividing unit 6. A rotational speed of the third rotating element of the first differential planetary gear unit P1 is changed according to the rotational speed of the variable-speed motor 70, i.e., the rotational speed of the second output shaft 83 serving as a speed-change shaft. As a result, the rotational speed of the first output shaft 81 is changed.

0145<figref idref="f0013">FIG. 14</figref> shows another transmission apparatus. An example shown in <figref idref="f0013">FIG. 14</figref> is a modification of the transmission apparatus shown in <figref idref="f0011">FIG. 12</figref>, and corresponding parts are denoted by the same reference numerals. Only different parts will be described below.

0146In the example shown in <figref idref="f0013">FIG. 14</figref>, a clutch 90 is provided on an output shaft 72 of the second differential planetary gear unit P2. An output shaft 69 of the variable-speed motor 70 is connected to the second differential planetary gear unit P2 via a speed-increasing gear unit 91 having a direct-coupling switch clutch (not shown). Further, a clutch 92 is provided on an output shaft 73.

0147In this example, the clutches 90 and 92 are disengaged, and the direct-coupling switch clutch is switched to the speed-increasing side. Then, the variable-speed motor 70 starts the drive unit such as a squirrel-cage induction motor. When the drive unit M is increased to a predetermined rotational speed, the drive unit M is energized. According to such an operation manner, electric power for the starting can be small.

0148Here also, the rotational powers transmitted via the direct-coupling shafts (output shafts) 73 and 81 are larger than the rotational powers transmitted via the speed-change shafts 72 and 83, respectively. Accordingly, even if the second differential planetary gear unit P2 and the variable-speed motor 70 each constituting the joint unit have a small capacity, it is possible to appropriately change the rotational speed of the load L having a large capacity.

0149However, if a negative rotational power is transmitted to the speed-change shafts 72 and 83, i.e., if feedback occurs, the rotational power to be transmitted to the direct-coupling shafts 73 and 81 becomes large by the same amount. Therefore, it is important in designing the transmission apparatus to prevent the feedback from occurring at any rotational speed.

0150<figref idref="f0014">FIGS. 15</figref> and <figref idref="f0015">16</figref> show another transmission apparatus which is a modification of <figref idref="f0011">Fig. 12</figref>. As with the <figref idref="f0013">FIG. 14</figref>, those parts corresponding to those in <figref idref="f0011">FIG. 12</figref> are denoted by the same reference numerals, and only different parts will be described below.

0151In an example shown in <figref idref="f0014">FIGS. 15</figref> and <figref idref="f0015">16</figref>, a clutch 90 is provided on the output shaft 72 of the second differential planetary gear unit P2, i.e., a speed-change shaft. The variable-speed motor 70 is controlled by an inverter controller 100. When the load L is decelerated, the variable-speed motor 70 is utilized as a generator and supplies current to a work W, whereby the variable-speed motor 70 is utilized as a brake, as described later. As with the example shown in <figref idref="f0013">FIG. 14</figref>, a clutch 92 is provided on the direct-coupling shaft 73. A reference sign S in the drawing represents a rotation sensor of the load L.

0152When the variable-speed motor 70 is utilized as a brake, the work W can be applied to a variety of actions such as heat generation due to resistance, storing electricity to a storage battery, and selling electricity to a commercial power source through a frequency inverter.

0153Operation will be described with reference to <figref idref="f0015">FIG. 16</figref>. A controller unit (not shown) receives a signal from the rotation sensor S and then sends a switching signal to the inverter controller 100 for the work W.

0154First, the control unit reads the signal from the rotational sensor S (step S1), and decides whether or not the load L is decelerated (step S2). In the case of NO in step S2, then the variable-speed motor 70 is used as a motor (step S3), and the control unit decides whether or not the control is finished (step S6). If the control is not finished, then the process proceeds to step S1. If the control is finished, then the operation is finished.

0155In the case of YES in step S2, i.e., when the load L is decelerated, the control unit stops the supply of the electric power to the variable-speed motor 70 and switches connection of the variable-speed motor 70 to the work W (step S4). As a result, the variable-speed motor 70 acts as a generator to perform braking (step S5). Then, whether the control is finished or not is decided (step S6).

0156<figref idref="f0016">FIG. 17</figref> shows a modification of <figref idref="f0011">FIG. 12</figref>. In the transmission apparatus shown in <figref idref="f0016">FIG. 17</figref>, the direct-coupling shaft 73 is coupled to the first rotating element of the first differential planetary gear unit P1 via a first speed-increasing or speed-decreasing gear 101. The output shaft 72 of the second differential planetary gear unit P2 is coupled to the second rotating element of the first differential planetary gear unit P1 via a second speed-increasing or speed-decreasing gear 102. The third rotating element of the first differential planetary gear unit P1 is coupled to the load L via a third speed-increasing or speed-decreasing gear 103 and the output shaft 80.

0157Since the speed-increasing or speed-decreasing gears 101 through 103 are provided as described above, distribution of power flow can be optimized and operation manner of the load L can be diversified.

0158According to the transmission apparatus shown in <figref idref="f0011 f0012 f0013 f0014 f0015 f0016">FIGS. 12 through 17</figref>, because the joint unit is constituted by a combination of the second differential planetary gear unit and the variable-speed motor, a smooth speed-change operation can be performed by changing the speed of the variable-speed motor. Further, because the rotational power can be transmitted mainly via the coupling shaft serving as the direct-coupling shaft coupling the first differential planetary gear unit and the dividing unit, the capacity of the second differential planetary gear unit and the variable-speed motor as the joint unit can be small. As a result, it is possible to provide a transmission apparatus which can perform an efficient speed-change operation with small impact.

Industrial Applicability

0159The present invention is suitable for use in a transmission apparatus having at least one of a dividing unit and a differential planetary gear unit and having a joint unit.