Pulley unit with one-way clutch

【0001】

[Technical field to which the invention belongs]

The present invention relates to a pulley unit with a unidirectional clutch used in a belt drive starter, for example, in a belt transmission system in which a belt transmits a rotational force when an internal combustion engine is started and when an auxiliary machine is driven by the internal combustion engine.

【0002】

[Conventional technology]

Conventionally, as a pulley unit with a one-way clutch, the inner ring, the outer ring, and the biting member and the biting member arranged between the two wheels are bitten in the biting direction between the hollow shaft and the pulleys arranged concentrically around the hollow shaft. A one-way clutch equipped with an urging member for urging is provided, and a tool fitting portion for fitting a prismatic portion of the tool is provided in the opening of the hollow shaft, and a female screw portion is connected to the portion. What is formed is known (Patent Document 1).

【0003】

[Patent Document 1]

Japanese Unexamined Patent Publication No. 11-270658 [0004]

[Problems to be Solved by the Invention]

In the conventional pulley unit with a one-way clutch, when attaching this pulley unit to the rotating shaft, the tool can be fitted to the tool fitting portion and rotated, and the pulley can be attached to the rotating shaft without using a nut. Since the unit can be attached, it has the advantage that the axial dimension can be reduced by the amount of the nut. However, in this conventional one, if it is attempted to increase the diameter of the rotating shaft in order to increase its strength, there is a problem that it is necessary to increase the diameter of the tool fitting portion and therefore the diameter of the entire pulley unit. The problem is to increase the diameter of the rotating shaft without increasing the overall diameter.

【0005】

An object of the present invention is to provide a pulley unit with a unidirectional clutch capable of increasing the diameter of a rotating shaft without increasing the diameter of the entire unit.

【0006】

[Means for Solving Problems and Effects of Invention]

In the pulley unit with a one-way clutch according to the present invention, the inner ring, the outer ring, and the biting member and the biting member arranged between the two wheels are bitten between the hollow shaft and the pulleys arranged concentrically around the hollow shaft. A one-way clutch with a urging member for urging in the direction is provided, a tool fitting portion for fitting a tool is provided in the opening of the hollow shaft, and a female screw portion is formed in connection with the portion. The pulley unit with a one-way clutch is characterized in that the inscribed circle diameter of the tool fitting portion <the valley diameter of the female thread portion <the circumscribed circle diameter of the tool fitting portion.

【0007】

The inscribed circle diameter of the tool fitting portion means the diameter of the smallest circle in the cross-sectional shape that is centered on the shaft of the hollow shaft and passes through the meat portion of the hollow shaft. The circumscribed circle diameter of the tool fitting portion means the diameter of the largest circle. The tool fitting portion is typically a hexagonal columnar corresponding to a hexagonal wrench, in which case the inscribed circle diameter of the tool fitting portion is the width across flats of the hexagonal portion and the circumscribed circle of the tool fitting portion. The diameter of the circle is the length of the longest diagonal line (diagonal line passing through the center) of the hexagonal portion. The tool and the tool fitting portion can have various shapes, and the shape of the tool fitting portion formed corresponding to the shape of the tool may be a polygon other than a hexagon, and may be a serration or a star shape. The shape is not particularly limited as long as it is non-circular.

【0008】

The one-way clutch may be a sprag type clutch having a sprag as a biting member and a spring for urging the clutch as an operating member, and a roller as a biting member and urging the roller. It may be a roller type having a spring as an operating member.

【0009】

The one-way clutch is arranged in a wedge-shaped space formed by a cam surface provided on the outer peripheral surface of the hollow shaft as an inner ring and an inner peripheral surface of the pulley as an outer ring, and the shaft and the pulley are one. By rotating relative to the direction of, it bites between the shaft and the pulley, and when it rotates relative to the other direction, it releases the bite. It may be configured to have a coil spring as an urging member (narrow side) (narrow side) (inner ring cam type), and a cam surface provided on the inner peripheral surface of the pulley as an outer ring and a cam. It is arranged in a wedge-shaped space formed by a surface and an outer peripheral surface of the shaft as an inner ring, and the shaft and the pulley rotate relative to each other in one direction to engage between the shaft and the pulley and relative to the other direction. A configuration including a roller as a plurality of biting members that release the bite when rotated and a coil spring as a biasing member that biases the roller in the biting direction (narrow side of the wedge-shaped space) (outer ring cam type). ) May be.

【0010】

According to the pulley unit with a one-way clutch of the present invention, the inscribed circle diameter of the tool fitting portion <the valley diameter of the female thread portion <the circumscribed circle diameter of the tool fitting portion, so that the outer diameter of the pulley is not increased. In addition, the diameter of the rotating shaft can be increased, whereby the strength of the rotating shaft can be improved without affecting the pulley side.

【0011】

In the pulley unit with a one-way clutch of the present invention, it is preferable that the pulley and the outer ring of the one-way clutch are integrated. In this way, the PCD of the biting member (splug, roller) of the one-way clutch can be increased while suppressing the outer diameter of the pulley, and as a result, the centrifugal force acting on the biting member becomes large, and when idling. It is possible to secure a non-contact state between the biting member and the shaft in the above.

【0012】

The one-way clutch is provided between the shaft and the axial intermediate portion of the pulley, and it is preferable that a roller bearing and a ball bearing are provided between the shaft and the pulley with the one-way clutch interposed therebetween. In this way, the pulley can rotate at high speed, and this unit can be suitably used as a belt drive starter for an automobile engine.

【0013】

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiments of the present invention will be described below with reference to the drawings.

【0014】

FIG. 1 shows a pulley unit with a one-way clutch according to the present invention. This pulley unit with a one-way clutch (1) is arranged at a portion that connects the drive unit of the engine and the rotating shaft of the starter motor, and is a hollow shaft (3) fitted to the rotating shaft (2) of the starter motor. ) And a pulley (4) arranged concentrically with the pulley (4), a one-way clutch (5) is provided. A belt hanging portion (4a) on which the V-ribbed belt (B) is hung is provided on the outer circumference of the pulley (4).

【0015】

The one-way clutch (5) is provided between the hollow shaft (3) and the axial intermediate portion of the pulley (4), and is formed between the hollow shaft (3) and the portion of the pulley (4) near each end. A roller bearing (6) and a ball bearing (7) are provided between them with a unidirectional clutch (5) in between. Then, the outer ring of the pulley (4) and the one-way clutch (5) and the outer ring of the bearing (6) (7) are integrated, and the inner ring of the hollow shaft (3) and the one-way clutch (5) and the bearing ( 6) The inner ring of (7) is integrated to reduce the number of parts.

【0016】

Seal members (8) and (9) are arranged on the outer side of the roller bearing (6) and the ball bearing (7) in the axial direction, respectively, and the pulley is on the free end side (left end side in the figure) of the pulley unit. Another sealing member (10) is arranged inside the unit to prevent the intrusion of muddy water and the like.

【0017】

As shown in FIG. 2, the one-way clutch (5) is provided by a cam surface (11) provided on the inner peripheral surface of the pulley (4), a cam surface (11), and an outer peripheral surface of the hollow shaft (3). Arranged in the formed wedge-shaped space (12), the hollow shaft (3) and the pulley (4) rotate relative to each other in one direction (locking direction), so that the hollow shaft (3) and the pulley (4) are connected to each other. Rollers (13) as multiple biting members that bite in between and release biting when relative rotation in the other direction (free direction) and rollers (13) in the biting direction (wedge-shaped space (12)) It is equipped with a coil spring (14) as an urging member for urging the narrow side) and a cage (15) for locating the rollers (13) in the wedge-shaped space (12).

【0018】

The cam surface (11) is configured by providing a plurality of sets (4 sets in this embodiment) of two parallel faces (11a) (11b) (11c) (11d) facing each other with the axial center in between. There is. Each of the two parallel faces (11a) (11b) (11c) (11d) is not perpendicular to the normal (19) passing through the center and axis of the roller (13), but has an acute angle slightly smaller than the right angle. Has been done. By providing the cam surface (11) on the pulley (4) in this way, the pulley (4) is given a function as an outer ring of the one-way clutch (5), and the pulley (4) and the one-way clutch (5) are provided. ) Is integrated with the outer ring. As a result, the PCD of the roller (13) can be increased while suppressing the outer diameter of the pulley (4), and the centrifugal force acting on the roller (13) is large.

【0019】

At the end of the wide side of the wedge-shaped space (12) of the two parallel surfaces (11a) (11b) (11c) (11d), the cross section is arcuate and the roller (13) is stopped when it receives centrifugal force. A concave portion (16) is provided. The concave surface portion (16) has an arc shape having a radius substantially the same as the radius of the outer peripheral surface of the roller (13).

【0020】

The coil spring (14) has a central axis in the cross section, and has an elliptical shape in which the direction of the major axis coincides with the axial direction of the unidirectional clutch (5). Then, the length of the minor axis and therefore the radial dimension of the portion in contact with the roller of the spring is made smaller than the diameter of the roller (13).

【0021】

The cage (15) is made of synthetic resin and has an outer peripheral shape substantially along the cam surface (11) and an inner peripheral shape along the outer peripheral surface of the hollow shaft (3), and is inside the cam surface (11). It is press-fitted. There is a slight gap between the cage (15) and the outer circumference of the hollow shaft (3). The cage (15) is provided with a spring receiving recess (17) for positioning the coil spring (14). Grease is sealed in the spring receiving recess (17).

【0022】

The spring receiving recess (17) is connected to the roller holding concave portion (16) of the cam surface (11) and is connected to the spring positioning surface (18) provided on the inner circumference of the pulley (4) to form the coil spring (14). The direction of the central axis is kept constant. The central axis of the coil spring (14) is formed on the outer peripheral surface of the hollow shaft (3) so that it is deformed in a direction that reduces the urging force against the roller (13) when a centrifugal force acts on the coil spring (14). It is tilted with respect to the tangential direction. Similar to the cam surface (11), the spring positioning surface (18) of the pulley (4) consists of four sets of two surfaces formed in parallel facing each other with the axial center of the one-way clutch (5) in the circumferential direction. It is configured by being provided.

【0023】

The spring receiving recess (17) has a spring end positioning surface (17a) that prevents the coil spring (14) from moving in the spring axial direction, and the coil spring (14) moves inwardly perpendicular to the spring axis. It has a spring inner positioning surface (17b) that prevents the coil spring (14) from moving outward, which is orthogonal to the spring axis, and the spring positioning surface (18) of the pulley (4). It is a spring outer positioning surface that prevents it. Due to these spring positioning surfaces (17a) (17b) (18), the central axis of the coil spring (14) is orthogonal to the central axis of the roller (13), and the two parallel surfaces (11a) (11a) of the cam surface (11). It is kept parallel to 11b) (11c) (11d).

【0024】

A roller holding inclined surface (17c) is provided so as to be connected to the spring inner positioning surface (17b) of the spring receiving recess (17). The other end of the inclined surface (17c) is designed to have a slight gap with respect to the outer peripheral surface of the hollow shaft (3). When the pulley (4) is moved in the biting release direction by the roller holding concave surface (16) which is the roller holding surface and the roller holding inclined surface (17c) which is the roller holding surface of the cage (15). A roller holding portion having a substantially C-shaped cross section is formed to receive and hold 13).

【0025】

FIG. 2 shows a state in which no centrifugal force is applied to the rollers (13) and the coil springs (14), and when the hollow shaft (3) is rotated counterclockwise in this state, the rollers (13) are released. It is engaged between the hollow shaft (3) and the pulley (4), and the hollow shaft (3) and the pulley (4) rotate as one. Then, when the pulley (4) rotates at high speed and the rotation of the hollow shaft (3) is stopped, the direction of the centrifugal force acting on the roller (13) (the outward direction of the line indicated by the symbol (19)) ( Due to the deviation from the normal direction at the point where 13) is in contact with the two parallel planes (11a) (11b) (11c) (11d), the two parallel planes (11a) (11b) are on the roller (13). ) (11c) (11d) A directional force is applied, which causes the roller (13) to move to the wider side of the wedge-shaped space (12).

【0026】

In this state, the concave surface portion (16), which is the roller holding surface of the pulley (3), is a concave surface having an arcuate cross section with a radius substantially the same as the radius of the outer peripheral surface of the roller (13), and thus has a cylindrical surface. The outer peripheral portion of the roller (13) fits exactly in this concave surface portion (16), and the inclined surface (17c), which is the roller holding surface of the cage (15), is applied from the inside in the radial direction. The 13) does not tilt, a gap between the hollow shaft (3) and the outer peripheral portion (13) is secured, and a non-contact state with the hollow shaft (3) and the portion (13) is achieved.

【0027】

As shown in FIG. 1, the inner diameter of the pulley (4) is stepped, and the outer ring of the roller bearing (6), the outer ring of the one-way clutch (5), and the ball bearing of the pulley (4). Regarding the dimensions corresponding to each function of the outer ring of (7), the inner diameter of the outer ring raceway portion of the roller bearing (6) is D1, and the minimum inner diameter of the outer ring of the one-way clutch (5) (in this embodiment, the outer ring cam surface (11)). The distance between two parallel surfaces) is D2, and the inner diameter of the outer ring race shoulder of the ball bearing (7) is D3, and D1> D2 D3.

【0028】

The outer diameter of the hollow shaft (3) is constant except for the groove, and the outer diameter of the inner ring raceway of the roller bearing (6) = the inner diameter of the one-way clutch (5) = the outer diameter of the ball bearing (7). The outer diameter of the outer ring track shoulder. As a result, the outer diameter of the inner ring is suppressed, and it is easy to secure the dimensions of the one-way clutch. Further, the hollow shaft (3) can be machined by cold forging instead of being machined, whereby the machining cost of the pulley unit with a one-way clutch can be reduced. The HRC of the hollow shaft (3) is preferably 58 to 67 (for example, about 64).

【0029】

Seal grooves (8a) (9a) into which the raceway surface (7a) of the ball bearing (7) and the inner diameters of the sealing members (8) (9) (10) are fitted into the outer diameter of the hollow shaft (3). (10a) is provided. Further, the inner diameter of the hollow shaft (3) includes a female screw portion (3a) screwed to a male screw portion provided at the end of the rotation shaft (2) of the starter motor and a rotation shaft by rotating the hollow shaft (3). (2) A hexagonal tool fitting part (3b) is provided to which a hexagon wrench used for screwing to the end is fitted. Then, the inscribed circle diameter of the tool fitting portion (3b) (that is, the width across flats of the hexagonal portion) <the valley diameter (maximum diameter) of the female screw portion (3a) <the circumscribed circle diameter of the tool fitting portion (3b) (that is, The length of the longest diagonal line of the hexagonal portion), and the diameter of the portion of the rotating shaft (2) without the male thread portion is made larger than the width across flats of the tool fitting portion (3b).

【0030】

To attach this pulley unit (1) to the rotating shaft (2), fit a tool such as a hexagon wrench to the tool fitting part (3b), and then fit the unit (1) to the rotating shaft (2). The female threaded portion (3a) of the hollow shaft (3) and the male threaded portion of the rotating shaft (2) may be screwed together by covering and rotating the tool. The tightening direction of the screw at this time is opposite to the rotation direction of the rotation shaft (2).

【0031】

This pulley unit with a one-way clutch operates as follows.

【0032】

First, at the time of starting, the hollow shaft (3) integrated with the rotating shaft (2) of the starter motor is rotated counterclockwise. As a result, the roller (13) is engaged in the narrow side of the wedge-shaped space (12) of the one-way clutch (5), the driving force is transmitted, and the hollow shaft (3) and the pulley (4) are integrated. And rotate. The pulley (4) is connected to the crankshaft via a belt, and the rotation of the pulley (4) starts the engine. When the engine starts, the starter stops and the pulley (4) continues to rotate counterclockwise. As a result, the engagement of the roller (13) is released, and only the pulley (4) continues to rotate. In particular, when the engine rotates at high speed, the roller (13) is positioned by the concave portion (16) having almost the same curvature as the roller (13), and is in a non-contact state with the hollow shaft (3). Further, the coil spring (14) receives a force in the contracting direction due to a centrifugal force of the pulley (4) at a predetermined rotational speed or higher, and the elastic force for urging the roller (13) in the biting direction is reduced, resulting in a roller (14). A non-contact state between 13) and the hollow shaft (3) is ensured. Since the moving direction of the roller (13) and the central axis direction of the coil spring (14) coincide with each other when centrifugal force is applied, the coil spring (14) shifts when the roller (13) moves. , The urging force direction of the coil spring (14) does not change when the pulley (4) is stopped, and the problem that the roller (13) cannot be moved to the biting side does not occur. In this way, at the time of starting, the roller (engagement member) (13) and the coil spring (urging member) (14) rotate integrally with the outer ring, that is, the pulley (4), and then the pulley (4) is predetermined. When the rotation speed exceeds the rotation speed, only the pulley (4) rotates, and the energy loss associated with the rotation of the portion that does not contribute to the driving of the engine can be suppressed.

【0033】

When assembling this pulley unit (1), the ball and cage of the ball bearing (7), the coil springs (14) and rollers (13) of the one-way clutch (5), and the rollers and holding of the roller bearing (6). It may be inserted between the pulley (4) and the hollow shaft (3) in the order of the vessels. As described above, the inner diameter of the outer ring raceway (D1) of the roller bearing (6)> the distance between the two parallel surfaces of the outer ring cam surface (11) of the one-way clutch (5) (minimum inner diameter of the outer ring of the one-way clutch) (D2). ) Since the outer ring track shoulder inner diameter (D3) of the ball bearing (7), a work space is secured on the outer side in the radial direction during each insertion work, and the assembly work can be easily performed.

【0034】

Although the coil spring is shown above as a means for urging the roller (13), a leaf spring or the like can be used instead of the coil spring. Further, as the one-way clutch, the case where the biting member is a roller (13) is shown, but the biting member and the urging member rotate integrally with the outer ring, and the centrifugal force due to the predetermined rotation speed of the outer ring or more. If the clutch is a one-way clutch in which the biting member moves in the biting release direction and the urging force of the urging member has a magnitude that allows this movement, the one in which the biting member is a sprag is used. You can also do it.

【0035】

Further, in the above, the outer ring cam type in which a flat cam surface is formed on the inner peripheral surface of the outer ring has been described, but the size relationship between the diameters of the tool fitting portion and the female thread portion of the hollow shaft is the inner circumference of the outer ring. An outer ring cam type with an R-shaped cam surface formed on the surface, and an inner ring cam type one-way clutch, that is, a cam surface provided on the outer peripheral surface of the hollow shaft as the inner ring, and a pulley as the cam surface and the outer ring. It is arranged in a wedge-shaped space formed by the inner peripheral surface of the cam, and when the shaft and the pulley rotate relative to each other in one direction, it bites between the shaft and the pulley, and when it rotates relative to the other direction, it bites. It can also be applied to a roller as a plurality of biting members and a coil spring as a biasing member for urging the rollers in the biting direction (narrow side of the wedge-shaped space).

[Simple explanation of drawings]

FIG. 1 is a vertical cross-sectional view showing a first embodiment of a pulley unit with a one-way clutch according to the present invention.

FIG. 2 is a cross-sectional view of the same.

[Explanation of symbols]

(3) Hollow shaft (inner ring) (3a) Female thread part (3b) Tool fitting part (4) Pulley (outer ring) (5) One-way clutch (13) Roller (engagement member) (14) Coil spring (biasing) Element)