Compact manual transaxle.

COMPACT MANUAL DRIVE SHAFT

BACKGROUND-OF. 1 TO 1

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TION

This invention relates generally to manual multi-speed transmissions for use in motor vehicles. More specifically, the present invention is directed to a compact manual transmission shaft having a synchronized reverse gear.

Due to increased consumer demand for front wheel drive vehicles with more powerful yet fuel efficient drivetrains, the engine and driveshaft must be packed efficiently to take advantage of all available space within the engine compartment. Concomitantly, most modern drive shafts must be capable of providing at least five forward speeds. As such, minimizing the overall axial length of the driveshaft as well as its center shaft distances is of critical importance to the drive designer. To meet these requirements, various three-shaft type transmission shafts have been developed. For example, US Patent No. 4,738,150 discloses a five-speed manual transmission shaft having a feed shaft and a pair of intermediate transmissions or secondary shafts, both of which shift the differential which in turn shifts axle half arrows. Gear sets in both intermediate drives can be selectively coupled to supply power to the feed shaft to the semi-arrows - In addition, US Patent * Nos. 5,385,065 and 5,495,775 describe five speed driveshafts having a synchronized reverse gear assembly.

Accordingly, while these conventional manual driveshaft designs attempt to solve the aforementioned packaging requirements, there is still a need for the development of more compact and robust manual driveshafts that can meet the demands of vehicular applications with Modern front wheel scrolling.

COMPENDIUM OF THE INVENTION

The primary objective of the present invention is to provide a multi-speed manual transmission shaft, which meets the needs noted above and improves upon conventional designs.

For this purpose, the present invention is directed to a five-speed manual transmission shaft comprising a feed shaft, a first intermediate shaft having a first transfer gear fixed thereto, a first feed gear fixed to the feed shaft. feed, a first speed gear rotatably supported on the first intermediate shaft and engaged with the first feed gear, a second feed gear fixed to the feed shaft, a second speed gear rotatably supported on the first intermediate shaft and engaged with the second feed gear, a first synchro clutch for selectively engaging either of the first and second speed gears with the first intermediate shaft, a third feed gear fixed to the feed shaft, a third speed gear rotatably supported on the first intermediate shaft and engaged with the third feed gear, a fourth feed gear fixed on the feed shaft, a fourth speed gear rotatably supported on the first intermediate shaft and engaged with the fourth feed gear, a second synchronizing clutch for selectively engaging either the third and fourth speed gears with the first intermediate shaft, a second intermediate shaft having a second transfer gear fixed to it, a fifth feed gear fixed on the feed shaft, a fifth speed gear, rotatably supported on the second intermediate shaft and engaged with the fifth feed gear, a reverse gear rotatably held on the second intermediate shaft and engaged with the first speed gear, a third synchronizing clutch for selectively engaging either of the fifth speed gear and the reverse gear with the second intermediate shaft and a final displacement gear engaged with the first and second transfer gears.

BRIEF DESCRIPTION! OF THE DRAWINGS

Additional objects, features, and advantages of the present invention will be apparent to those skilled in the art from a study of the following description and accompanying drawings, wherein:

Figure 1 is a sectional view of a five-speed manual transmission shaft constructed in accordance with a preferred embodiment of the present invention;

Figure 2 is a partial sectional view of the five-speed manual transmission shaft illustrated in Figure 1;

Figure 3 is a schematic view showing the shaft and gear assembly for the driveshaft illustrated in Figure 1; Y

Figure 4 is a shift gate diagram for the driveshaft illustrated in Figure

1.

DETAILED DESCRIPTION OF ΤΛ PREFERRED MODE

Now referring to the drawings, a manual transmission shaft 10 is illustrated which is adapted for use in front wheel offset drive vehicles. The driveshaft 10 is a five-speed assembly that has all of its forward and reverse gears synchronized and yet is efficiently packed to provide a compact gearbox.

With particular reference to Figure 1, the driveshaft 10 is illustrated including a housing 12 within which a feed shaft 14 is rotatably supported by bearings 16 and 18 to rotate about a first axis A ". As is conventional, drive shaft 14 is adapted to travel through a convenient manually released clutch (not shown) by the vehicle engine. The driveshaft 10 is also illustrated as including a first intermediate or offset shaft 20 rotatably supported in the housing 12 by bearings 22 and 24 for rotation about a second axis. ^MB^tt, a second offset or intermediate shaft 26, rotatably supported in housing 12 by bearings 28 and 30 for rotation about a third axis Cⁿ, and a differential 32 supported in the housing 12 by bearings and 36 for rotation about a fourth axis D. As is also conventional, the output of the differential 32 includes a pair of axially aligned side gears

38 to which the axle half arrows 40 are attached in order to connect the differential 32 to the drive or drive wheels of the motor vehicle. The differential feed 32 is a final drive gear 42 fixed to the differential cage 44 and which is in constant meshing engagement with a first transfer gear 46 fixed to the first intermediate shaft 20 as well as with a second transfer gear 48 fixed. to the second intermediate shaft 26. It will be appreciated that the Figure is a so-called unfolded sectional view where arrows 14, 20, 26 and 40 are all arranged in a single plane. However, in reality, these arrows are arranged compactly parallel to each other, with none of the three in a common plane, as illustrated in Figure 3. In this way, the center distance between the arrows can be effectively minimized.

The driveshaft 10 includes a series of constant-engagement gear sets 50, 52, 54, 56, 58, and 60 that can be selectively engaged to establish five forward speed ratios as well as one reverse speed ratio between the gear shaft. feed 14 and final shift gear 42. The gear set 50 includes a first feed gear 62 fixed to the feed shaft 14 and a first speed gear 64 rotatably supported on the first intermediate shaft 20. The first speed gear 64 is in constant engagement with the first feed gear. feed 62 to define a first power transmission path that can be selectively coupled to establish a first ground speed ratio. Gear set 52 includes a second feed gear 66 fixed to feed shaft 14 that is in constant engagement with a second speed gear 68 rotatably supported on first intermediate shaft 20. In this manner, gear set 52 operates to define a second path for power transmission that can be selectively coupled to establish a second forward speed ratio. Gear set 54 includes a third feed gear 70 fixed to feed shaft 14 that is in constant engagement with a third speed gear 72 rotatably supported on first intermediate shaft 20. As such, gear set 54 functions to defining a third power transmission path that can be selectively coupled to establish a third forward speed ratio. Gear set 56 includes a fourth feed gear 74 fixed to feed shaft 14 that is in constant engagement with a fourth speed gear 76 rotatably supported on first intermediate shaft 20. In this manner, gear set 56 operates to define a fourth path for power transmission that can be selectively coupled to establish a fourth forward speed ratio. Gear set 58 includes a fifth feed gear 78 fixed to feed shaft 14 which mates with a fifth speed gear 80 rotatably supported on second intermediate shaft 26. Gear set 56 functions to define a fifth path for power transmission that can be selectively coupled to establish a fifth forward speed ratio. Finally, gear set 60 includes a reverse gear 82 rotatably held on intermediate shaft 26 that mates with fifth speed gear 64. Gear set 60 defines a sixth path for power transmission that can be selectively engaged to establish the inverse speed ratio.

To provide means of establishing the various forward and reverse speed ratios_t By selectively engaging one of the available power transmission paths, each gear set is associated with a synchronizing clutch. In particular, a first synchronizing clutch 84 is operatively located between first and second speed gears 64 and 68 and includes a hub 86 fixed to the first intermediate shaft 20, a shift sleeve 88 mounted for rotation with and axially sliding the movement of the hub. 86 and a pair of convenient lock-type synchronizers 90 sandwiched between shift sleeve 88 and speed gears 64 and 68. The first synchronizing clutch 84 is of the double acting variety, such that the forward axial movement of the shift sleeve 88 from its centered neutral position is adapted to engage the first speed gear 64 to the first intermediate shaft 20 to establish the first forward speed ratio, wherein the first transfer gear 46 displaces the final shift gear 42. Still further, the rearward axial movement of the shift sleeve 88 from its neutral position is adapted to engage the second speed gear 68 to the first intermediate shaft 20, such that the first transfer gear 46 displaces the downshift gear.

-910 final displacement 42 in the second ground speed ratio.

To establish the third and fourth forward speed relationships, a second synchronizing clutch 92 is located between the third and fourth speed gears 72 and 76 and includes a hub 94 fixed to the first intermediate shaft 20, a shift sleeve 96 mounted to rotation with and axial sliding movement in hub 94 and a pair of lock-type synchronizers 98, sandwiched between shift sleeve 96, third speed gear 70 and a clutch gear 100 fixed to fourth speed gear 76. The second synchronizing clutch 92 is of the double acting type, such that the forward axial movement of the shift sleeve 96 from its illustrated neutral centered position is adapted to engage the third speed gear 72 to the first intermediate shaft 20, as shown. such that the first transfer gear 40 moves the final shift gear 42 into the third forward speed ratio. Still further, the rearward movement of shift sleeve 96 from its centered neutral position is adapted to engage fourth speed gear 76 to first intermediate shaft 20, such that first transfer gear 46 displaces final shift gear 42 to the fourth gear ratio.

-1011

The forward fifth speed ratio and the reverse speed ratio are set by a fourth synchronizing clutch 102, again of the double acting variety that is located between the fifth speed gear 80 and the reverse gear 82. Synchronizing clutch 102 includes a hub 104 fixed to second intermediate shaft 26, a shift sleeve 106 mounted for rotation with and axial sliding movement in hub 104, and a pair of lock-type synchronizers 108 sandwiched between shift sleeve 114 , the reverse gear 82 and the clutch gear 110 fixed to the fifth speed gear 80, The rearward sliding movement of the shift sleeve 106 from its illustrated centered neutral position, is adapted to engage the clutch gear 110 and fifth speed gear 80 to the second intermediate shaft 26 such that the second transfer gear 48 moves the final shift gear 42 into the fifth speed ratio. In contrast, the forward sliding motion of the shift sleeve 106 from its neutral position engages the reverse gear 82 such that the reverse gear 82 releasably engages the second intermediate shaft 26. As such, the second shift gear Transfer 48 shifts the final shift gear 42 to the ratio of

-1112 reverse speed and in the opposite direction with respect to the normal direction of rotation of the final shift gear 42 during forward operation. This reversal of direction results from the reverse gear 82 being driven by the first speed gear 64 which in turn is being driven by the first feed gear 62.

In the first lead gear, torque is supplied from the feed shaft 14 to the differential 32 through elements 62, 64, 88, 86, 20, 46, and 42. In the second lead gear, the torque of torque is supplied from feed shaft 14 to differential 32 through elements 66, 68, 88, 86, 20, 46, and 42. In the third lead gear, torque is supplied from the feed shaft 14 to the differential 32 through elements 70, 72, 96, 94, 20, 46, and 42. In the fourth lead gear the torque is supplied from feed shaft 14 to differential 32 through elements 74, 76, 96, 94, 20, 46, and 42. In the fifth forward gear, torque is supplied from the feed shaft 14 to the differential 32 through the elements 78, 80, 106, 104, 26, 48 and 42. Finally, in the reverse gear, it is supplied torque from arrow of

-1213 supply 14 to differential 32 through elements 62, 64, 82, 106, 104, 26, 48 and 42.

Figure 3 is a schematic illustration of the mounting of arrows 14, 20, 26 and 40 and of the engagement of the various gear sets. In addition, a shift pattern or gate diagram for the driveshaft 10 is illustrated in Figure 4. Obviously, any convenient shift system that couples each of the shift sleeves 88, 96, and 106 to a gear shift lever (not shown) for coordinated movement, to set the various forward and reverse gears, can be used with the drive shaft 10.

The previous discussion illustrates and describes a presently preferred embodiment of the present invention. A person skilled in the art will readily recognize from this discussion and from the accompanying drawings and claims, that various changes and modifications and variations can be made without departing from the spirit and true meaning of the invention as defined in the following claims.