JP2000130471A - Unidirectional clutch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate locking failure by making tilting force to tilt sprags in a direction to bite into between inner and outer rings on a contact point with a guide surface of each of the sprags larger than friction force between the sprags working on the contact point and the guide surface. SOLUTION: A sprag 5 transmits torque by receiving pressing force F1 of a plate spring 6 and tilting in a direction to bite into between inner and outer rings 1, 2 at the time of increasing angular speed. At the time of reducing the angular speed, the sprag 5 tilts in a direction to slide on the inner and outer rings 1, 2, blocks torque transmission, the sprag 5 bites into between a guide surface 8 and the plate spring 6, and tilting in the biting direction is restrained by friction force F3 between the sprag 5 and the guide surface 8 working on a contact point Q with the guide surface 8 at the time of increasing the angular speed next time. At this time, tilting force F2 in the tangential direction to tilt the sprag 5 in the biting direction by receiving the pressing force F1 on the contact point Q works, and it is larger than the friction force F3, and the sprag 5 can tilt in the biting direction between the inner and outer rings 1, 2. Consequently, it is possible to eliminate locking failure at the time of increasing the angular speed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a torque transmission path for transmitting the torque of a crankshaft of an automobile engine that rotates with a minute angular velocity fluctuation to an accessory shaft of an accessory via a transmission belt. The present invention relates to a direction clutch, and more particularly, to a countermeasure against a lock failure when an angular velocity is increased due to a high frequency minute angular velocity fluctuation.

[0002]

2. Description of the Related Art For example, as described in Japanese Patent Application Laid-Open No. 61-228153, a torque transmission path for transmitting the torque of a crankshaft of an automobile engine to an accessory shaft of an accessory through a transmission belt is disclosed. It is known that the provision of the directional clutch can reduce the load on the power transmission belt by absorbing the minute angular velocity fluctuation of the torque caused by the explosion stroke of the engine. In particular, when the auxiliary device is an alternator, the effect of reducing the belt load is large because the inertia torque of the rotor is large.

[0003] At this time, the high-frequency minute angular velocity fluctuations in the high-speed rotation range of the engine (for example, 5000 rpm) have a small amplitude and are sufficiently absorbed by the elasticity of the transmission belt, so that the load on the transmission belt is also reduced. On the other hand, a small angular velocity fluctuation of a low frequency in a low-speed rotation range of the engine (for example, during idling) is large, and a large load is applied to the transmission belt. In particular, emphasis is placed on absorbing low-frequency minute angular velocity fluctuations in the low-speed rotation range of the engine.

Here, the structure of a conventional one-way clutch provided in the torque transmission path will be described. This is, as schematically shown in FIG. 4, arranged between the inner and outer rings a and b so as to be swingable in a plane orthogonal to the rotation axis of the inner and outer rings a and b. It tilts in the direction of biting between them (clockwise direction in the figure) to transmit torque between the inner and outer wheels a and b, while tilting in the direction of sliding contact with the inner and outer wheels a and b (counterclockwise direction in the figure). And sprags c, c,... For interrupting the torque transmission.
c, ... are constantly pressed to tilt to slidably guided while the bite direction the guide surface f of the cage e by the pressing force F ₁ of the plate spring d.

[0005] Specifically, in the swinging plane of the sprags c, sprags c extends from the pressing point P receiving a pressing force F ₁ of the leaf spring d in the direction of the pressing force F ₁ linear (one point in FIG. 4 The contact point Q of the sprag c with the guide surface f rather than the chain line)
Is positioned on the outer peripheral side, whereby the pressing force F ₁ acts tangentially on the contact point Q of the sprag c to tilt the sprag c in the biting direction F ₂ Has been made to convert.

[0006] Then, for example, a description will be given of a case where the torque from the crankshaft to the outer ring b is input, the sprags c, during the angular velocity increases in a minute angular speed variation of the crankshaft, receives the pressing force F ₁ of the leaf spring d While transmitting the torque between the inner and outer wheels a and b by tilting in the biting direction while moving the point of contact Q with the guide surface f to the outer peripheral side by the relative rotation of the outer wheel b in the locking direction, while the angular velocity is reduced. , tilt the sliding contact direction inner and outer rings a, the b while moving the contact point Q on the inner peripheral side against the relative rotation of the free direction of the outer ring b to the pressing force F ₁ of the leaf spring d, above this The torque transmission is interrupted.

[0007]

However, in the above-described conventional one-way clutch, there is a problem that a high frequency (for example, 160 Hz) minute angular speed fluctuation in a high speed rotation range of the engine easily causes a lock failure.

The reason is that, when the sprag c is tilted in a direction in which it slides on the inner and outer wheels a and b by the relative rotation of the outer ring b in the free direction, the sprag c is moved by the leaf spring d and the guide surface f.
When the outer ring b is relatively rotated in the locking direction due to the frictional force with the guide surface f, the sprag c
Of the sprag c in the direction of biting between the inner and outer wheels a and b is suppressed. As a result, generally, the followability of the sprag c with respect to the minute angular velocity fluctuation is reduced in accordance with the increase in the engine speed. It is considered that a lock failure easily occurs.

The present invention has been made in view of the above points, and a main object thereof is that a sprag is guided to a guide surface of a retainer between a inner race and an outer race in a torque transmission path accompanied by a minute angular velocity fluctuation. When arranging a one-way clutch that is constantly pressed by the pressing member so as to tilt in the biting direction, the sprags can be tilted in the biting direction regardless of the frictional force between the sprags and the guide surface, Thus, when used in a belt-type accessory drive device of an automobile engine, it is possible to contribute to the elimination of a lock failure at the time of an increase in angular velocity due to a high-frequency minute angular velocity fluctuation in a high-speed rotation range of the engine.

[0010]

In order to achieve the above object, according to the present invention, a contact point between a sprag swinging plane and a guide surface of a retainer is set closer to the outer peripheral side than in the conventional case. By positioning, the tilting force acting on the contact point is made larger than the frictional force acting between the contact point and the guide surface.

Specifically, according to the first aspect of the present invention, an inner ring and an outer ring rotatably mounted on the inner ring are provided;
Each is arranged between the inner and outer wheels so as to be swingable in a plane orthogonal to the rotation axis of the inner and outer wheels, and tilts in a direction to lock the relative rotation of the inner and outer wheels to transmit torque between the inner and outer wheels. A plurality of sprags that are tilted in a direction to make the relative rotation of the inner and outer races free to cut off the torque transmission, and the sprags are provided so as to be orthogonal to a swing plane of the sprags and swing when the corresponding sprags swing. A plurality of guide surfaces slidably guide, a ring-shaped retainer arranged concentrically between the inner and outer rings, and a guide surface of the retainer on the swing plane of the corresponding sprag, respectively. A one-way clutch provided with a plurality of pressing members that constantly presses so as to incline in a direction of biting between the inner and outer wheels while moving the contact point of the one-way clutch.

[0012] Then, the tangential direction of the tilting force F ₂ acting to tilt in the direction of biting the sprags between the inner outer ring contact point with the corresponding guide surfaces of the sprags acts on the contact point sprag And the frictional force F between the guide surfaces
It is assumed that the value is set to be larger than ₃ (F ₂ > F ₃ ).

In the above configuration, when the torque accompanied by the minute angular speed fluctuation is input to the one-way clutch, the sprags are connected to the guide surface of the retainer so as to disconnect and connect the torque transmission between the inner and outer wheels according to the minute angular speed fluctuation. Swings while being slidably guided by the robot. In other words, when the angular velocity of the minute angular velocity fluctuation is increased, the sprags, while receiving the pressing force of the pressing member, move into the contact point with the guide surface of the retainer due to the relative rotation of the inner and outer rings in the locking direction and bite between the inner and outer rings. To transmit torque between the inner and outer wheels. On the other hand, when the angular velocity of the minute angular velocity fluctuation decreases, the sprags tilt in the direction of sliding contact with the inner and outer wheels while moving the contact point with the guide surface against the pressing force of the pressing member due to the relative rotation of the inner and outer wheels in the free direction. ,
This interrupts the torque transmission. Then, since the sprags bite between the guide surface and the pressing member due to the tilting in the sliding contact direction, when the inner and outer rings relatively rotate in the lock direction at the next increase in angular velocity, the sprags are brought into contact with the guide surface. so that the tilting of the bite direction is suppressed by the frictional force F ₃ between the sprags and the guide surface acts.

[0014] At this time, the contact point of the sprag, and acts tangential tilting force F ₂ which tends to tilt in the direction bite the sprags by receiving the pressing force of the pressing member,
The tilting force F ₂ is greater than the frictional force F ₃ (F ₂
> F ₃ ). Therefore, bites between the guide surface and the pressing member of the retainer when the angular velocity decreases in a minute angular speed variation sprags, during increased following angular velocity between the inner and outer rings against the frictional force F ₃ between the guide surface You will be able to tilt in the biting direction.

According to a second aspect of the present invention, in the first aspect of the present invention, the sprag is made of steel, and at least the guide surface of the retainer is formed of resin, and is schematically shown in FIG. As described above, each pressing member 6
Is configured to always press the sprags 5 in a direction perpendicular to the guide surface 8, the sprags 5 apply the pressing force F ₁ of the pressing member 6 on the swing plane of each of the sprags 5. With respect to a reference line L extending from the received pressing point P in a direction orthogonal to the guide surface 8, the pressing point P of the sprag 5
And the sprag support angle θ formed by the straight line M between the contact point Q is θ
It is assumed that ≧ 12 ° is set.

In the above configuration, the tangents acting to tilt the sprags 5 at the contact points Q of the respective sprags 5 with the guide surface 8 in the direction of biting between the inner and outer rings 1 and 2 (clockwise direction in FIG. 1). force (tilting force) F ₂ is, F ₂ = F ₁
× tan θ. On the other hand, assuming that the friction coefficient between the sprag 5 and the guide surface 8 is μ, the frictional force F acting on the contact point Q of the sprag 5 by the pressing force F ₁ of the pressing member 6
₃ is represented by F ₃ = F ₁ × μ. Therefore, F ₂ > F ₃
Is satisfied, tan θ> μ (θ> tan ⁻¹ μ) is a condition. In other words, if tan θ> μ, F ₂ > F ₃ holds regardless of the magnitude of the pressing force F ₁ of the pressing member 6.

Here, the coefficient of friction μ between steel and resin is
Generally, μ = 0.1 to 0.2 (tan ⁻¹ μ = 5.710)
5 ... to 11.3099 ...). The sprag support angle θ is θ ≧ 12 ° (> 11.3099 ...
≧ tan ⁻¹ μ), which is larger than tan ⁻¹ μ, so that the above condition of tan θ> μ (θ> tan ⁻¹ μ) is satisfied. Therefore, the operation according to the first aspect of the present invention can be performed specifically and efficiently.

According to the third aspect of the present invention, in the first or second aspect,
The one-way clutch according to the invention is arranged in a torque transmission path for transmitting torque of a crankshaft rotating with a minute angular speed variation due to an explosion stroke of an automobile engine to an accessory shaft of an accessory via a transmission belt. And

In the above configuration, when a torque accompanied by a minute angular speed variation is input to the one-way clutch from the crankshaft of the automobile engine, the tilting power acting on the contact point of the sprag acts on the contact point. Since it is larger than the frictional force between the sprag and the guide surface, it is possible to contribute to the elimination of the lock failure of the one-way clutch when the angular speed is increased with respect to the high-frequency minute angular speed fluctuation in the high-speed rotation range of the engine. .

According to a fourth aspect of the present invention, in the third aspect of the present invention, a pulley for winding a transmission belt is provided on the outer periphery of the outer race.

In the above configuration, a pulley for winding the transmission belt is provided on the outer periphery of the outer ring of the one-way clutch, and the pulley with a built-in one-way clutch is formed. Is attached to, for example, an accessory shaft of an accessory, thereby forming a torque transmission path between the crankshaft of the automobile engine and the accessory shaft of the accessory via the transmission belt. Therefore, the operation according to the third aspect of the invention is properly performed.

[0022]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 3 schematically shows a layout of a belt-type accessory drive device of an automobile engine provided with a pulley A with a built-in one-way clutch according to an embodiment of the present invention. A drive pulley 21 and an alternator 22 are disposed at one end of a four-cylinder four-cycle engine 20 mounted on a crankshaft 20a which rotates with a slight change in angular velocity caused by an explosion stroke of the engine 20. A so-called serpentine layout in which one V-ribbed belt 23 as a transmission belt is wound in a meandering manner between a plurality of driven pulleys attached to each auxiliary shaft of a plurality of auxiliary machines including the auxiliary pulley. is there.

More specifically, the driving pulley 21 shown in FIG.
The pulley 24 of the auto tensioner, the pulley 25 for the hydraulic pump of the power steering device, the idler pulley 26, the pulley 27 for the compressor of the air conditioner, and the pulley 28 for the engine cooling fan are shown in the order of the running direction of the V-ribbed belt 23 indicated by arrows. Is arranged. The one-way clutch built-in pulley A is disposed between the tension pulley 24 of the auto tensioner and the hydraulic pump pulley 25 of the power steering device.
The rotor is mounted on an alternator shaft 22a of the alternator 22 having a relatively large inertia torque.

The pulley A with a built-in one-way clutch is shown in FIG.
As shown in FIG. 2, an inner ring 1 attached to the alternator shaft 22a so as to rotate integrally therewith, and a pulley 3 around which a V-ribbed belt 23 is wound around the outer periphery are provided so as to rotate integrally, and are rotatable relative to the inner ring 1. And steel balls 4a, 4 arranged between the inner and outer rings 1 and 2 on a single plane orthogonal to the rotation axis of the inner and outer rings.
, and a single row bearing 4 consisting of a deep groove ball bearing having a ring-shaped retainer 4b for rollingly holding the steel balls 4a, 4a,. It is arranged so as to be swingable in a plane orthogonal to the rotation axis, and is tilted in a direction (clockwise in FIG. 1) that bites between the inner and outer wheels 1 and 2 to transmit torque between the inner and outer wheels 1 and 2. On the other hand, the sprags 5, which incline in the direction of sliding contact with the inner and outer rings 1 and 2 (counterclockwise direction in FIG.
, And leaf springs 6, 6,... Serving as pressing members for constantly pressing the corresponding sprags 5 so as to incline in a direction of biting between the inner and outer rings 1 and 2.

The retainer 4b of the single-row bearing 4 has a retaining hole 7 having a circular cross section provided so as to penetrate in the radial direction.
, and holding holes 7b, 7b,... having a rectangular cross section, which are also provided so as to penetrate in the radial direction, are arranged at a predetermined pitch in the circumferential direction in a fixed pattern (for example, alternately).
Are stored in the former holding holes 7a, 7a,..., And sprags 5, 5,... Are stored in the latter holding holes 7b, 7b,. That is, the steel balls 4a, 4a,...
, Are arranged in the same plane. The outer peripheral surface 1a of the inner race 1 and the inner peripheral surface 2a of the outer race 2 have
Deep grooves 1b and 2b having an arc-shaped cross section for rollingly guiding the steel balls 4a, 4a,.

The inner wall surface on the left side in FIGS. 1 and 2 among the two circumferentially opposite inner wall surfaces of the holding holes 7b for accommodating the sprags 5, 5,. A guide surface 8 is provided to guide the sprag 5 slidably. The retainer 4b is a resin retainer body having a plurality of recesses each of which is open at one axial end (lower side in FIG. 2) so as to form three inner wall surfaces of the corresponding retaining hole 7. 9 and one holding hole 7 at one axial end of the retainer body 9.
And an auxiliary plate 10 joined so as to form the remaining inner wall surfaces. In addition, the retainer body 9 includes
An insertion hole 11 that opens the corresponding holding hole 7 at the other axial end (the upper side in FIG. 2) is provided.

Each of the leaf springs 6 is bent and raised toward one axial end from a single ring-shaped leaf spring member 12 joined to the other axial end face of the retainer body 9. The guide surface 8 of the holding hole 7 is arranged so as to be inserted between the inner wall surface 13 on the opposite side in the circumferential direction and the sprag 5 through the insertion hole 11, whereby the sprag 5 is connected to the guide surface 8. Pressing is always performed in the pressing direction. The direction of the pressing force F ₁ is set so as to be orthogonal to the guide surface 8. The leaf spring 6 is formed in a tapered shape in which the width dimension gradually decreases toward the distal end.

Each of the sprags 5 is provided on the outer peripheral surface 1 a of the inner race 1.
And the respective contact surfaces of the outer ring 2 with the inner peripheral surface 2a are cam surfaces 5a, 5a.
b, the outer ring 2 is tilted by the relative rotation in accordance with the relative rotation direction of the outer ring 2 with respect to the inner ring 1. That is, when the outer wheel 2 relatively rotates in the locking direction when the angular speed is increased due to the minute angular speed fluctuation of the crankshaft 20a, each sprag 5 tilts in the direction of biting between the inner and outer wheels 1 and 2 by the relative rotation, while the angular speed decreases. Occasionally, when the outer ring 2 relatively rotates in the free direction, the outer ring 2 tilts in a direction in which it slides on the inner and outer rings 1 and 2 by the relative rotation.

Further, part of the sprag 5 that receives a pressing force F ₁ of the plate spring 6 is a convex portion 5c provided so as to bulge toward the leaf spring 6, while the leaf spring 6
Portion of the sprag 5 is pressed against the guide surface 8 by the pressing force F ₁ of is a slidable contact substantially arcuate cross section of the contact surface 5d on the guide surface 8. This contact surface 5d has a convex portion 5c.
And the pressing force F ₁ of the leaf spring 6 received by the sprag 5 is reduced by the contact point Q on the swing plane between the sprag 5 and the guide surface 8.
It is adapted to convert the tilting force F ₂ in the tangential direction that acts on. That is, by this tilting force F _2, the sprag 5
When the outer ring 2 is relatively rotated in the locking direction, the contact point Q is tilted in a direction to bite between the inner and outer rings 1 and 2 while moving the contact point Q to the outer peripheral side along the guide surface 8.

In this embodiment, the sprag 5
Q tilting force F ₂ in the tangential direction that acts on the contact point Q between the guiding surface 8, the contact point in the opposite direction to this tilting force F ₂
It is set to be larger (F _2> F ₃₎ than the frictional force F ₃ between the sprag 5 and the guide surface 8 acting.

Specifically, the coefficient of friction μ between the guide surface 8 of the retainer 4 and the sprag 5 is μ = 0.1 to 0.2.
Assumes that is, on the swinging plane of the sprags 5, with respect to the reference line L sprag 5 extends from the pressing point P receiving a pressing force F ₁ of the leaf spring 6 in the direction of the pressing force F _1, the sprag 5 The sprag support angle θ formed by the straight line M between the pressing point P and the contact point Q is set to θ ≧ 12 °.

Here, the operation of the pulley A with a built-in one-way clutch constructed as described above will be described. In the serpentine-type accessory drive device of the automobile engine 20,
When the torque of the crankshaft 20a accompanied by the minute angular velocity fluctuation is input to the one-way clutch built-in pulley A via the V-ribbed belt 23, each sprag 5 transmits the torque between the inner and outer wheels 1 and 2 according to the minute angular velocity fluctuation. To connect and disconnect
It swings while being slidably guided by the corresponding guide surface 8 of the retainer 4. That is, when the angular velocity of the minute angular velocity fluctuation is increased, the sprag 5 receives the pressing force F ₁ of the leaf spring 6 and the guide surface 8 by the relative rotation of the outer ring 2 in the locking direction.
While moving the contact point Q to the outer peripheral side, it is tilted in a direction to bite between the inner and outer wheels 1 and 2 to transmit torque between the inner and outer wheels 1 and 2.

On the other hand, when the angular velocity of the minute angular velocity fluctuation is decreased, the sprags 5 move the contact point Q with the guide surface 8 on the inner periphery against the pressing force F ₁ of the leaf spring 6 due to the relative rotation of the outer ring 2 in the free direction. While moving to the side, it is tilted in the direction in which it comes into sliding contact with the inner and outer wheels 1 and 2, thereby interrupting the torque transmission. Then, the sprags 5 bite between the guide surface 8 and the leaf spring 6 due to the tilting in the sliding contact direction, so that when the outer ring 2 relatively rotates in the lock direction at the next increase in angular velocity, the sprags 5 are moved to the guide surface. the frictional force F ₃ between the sprag 5 and the guide surface 8 acting on the contact point Q between 8 so that the tilting of the bite direction is suppressed.

[0034] At this time, the contact point Q of the sprags 5, tangential tilting force F ₂ which tends to tilt in the direction bite the sprags 5 by receiving the pressing force F ₁ of the leaf spring 6 acts cage, the tilting force F ₂ is greater than the frictional force _{F 3 (F 2> F 3} ). Therefore, the sprags 5 that have digged between the guide surface 8 of the retainer 4 and the leaf spring 6 when the angular velocity in the minute angular velocity fluctuation is reduced,
It becomes possible to tilt in the direction of biting between the inner and outer rings 1 and 2 against the frictional force F ₃ between the guide surface 8 and the guide surface 8.

Therefore, according to the present embodiment, the torque of the crankshaft 20a which rotates with the minute angular velocity fluctuation due to the explosion stroke of the automobile engine 20 is applied to the V-ribbed belt 2.
Each sprag 5 is guided by the corresponding guide surface 8 of the retainer 4 on the alternator shaft 22a of the alternator 22 transmitted through the third spring 3 so as to be tilted in a direction of biting between the inner and outer rings 1 and 2. When the one-way clutch built-in pulley A constantly pressed by 6 is attached, the sprag support angle θ is set to θ ≧ 12 °, whereby the tilting power F ₂ acting on the contact point Q of the sprag 5 is This tilting power F ₂
Sprag by friction since so as to be larger than _{(F 2> F 3) F} 3, relative rotation of the lock direction of the outer ring 2 between the sprag 5 and the guide surface 8 acting on the contact point Q in a direction opposite to the 5 can be reliably tilted in the direction of biting between the inner and outer rings 1 and 2, and thus high frequency (for example, 1 rpm at 5000 rpm) in the high-speed rotation range of the engine 20 can be obtained.
(60 to 170 Hz), which can greatly contribute to the elimination of a lock failure at the time of an increase in angular velocity due to a small angular velocity fluctuation.

In the above embodiment, in order to assemble the inner and outer rings 1 and 2 so as to be relatively rotatable, one single row of steel balls 4a, 4a,. Although the bearings 4 are used, other types of bearings may be used in the present invention, and the axial arrangement and the number of bearings used are not particularly limited.

In the above embodiment, the leaf springs 6, 6,
.. Constitute a pressing member for each sprag 5, but as the pressing member, a known member other than the leaf springs 6, 6,.

Further, in the above embodiment, the pressing force F ₁ for each sprag 5 is set to act in a direction orthogonal to the guide surface 8, but the direction of the pressing force F ₁ is orthogonal to the guide surface 8. The present invention can be applied to cases where there is no such device.

Furthermore, in the above-described embodiment, the case of the pulley A with a built-in one-way clutch in which the pulley has a built-in one-way clutch has been described. However, the present invention can be applied to other one-way clutches. it can.

[0040]

As described above, the sprags, which are swingably arranged between the inner and outer wheels, are constantly pressed by the pressing members so as to be guided by the guide surface of the retainer and tilt in the direction of biting between the inner and outer wheels. In the one-way clutch,
Since the tilting force acting on the contact point between the sprag and the guide surface is set to be larger than the frictional force between the sprag and the guide surface acting on the contact point, the sprag is moved when the inner and outer rings rotate relative to each other in the locking direction. It can be tilted in the direction of biting between the inner and outer wheels against the frictional force, and can contribute to the elimination of the lock failure at the time of an increase in the angular velocity with respect to the input torque accompanied by the minute angular velocity fluctuation of high frequency.

According to the second aspect of the invention, the sprags are made of steel, at least the guide surface of the retainer is formed of resin, and each pressing member always presses the sprags in a direction orthogonal to the guide surface. In this case, the sprag support angle is set to 12 ° or more, so that the effect of the first aspect of the present invention can be specifically and efficiently obtained.

According to the third aspect of the present invention, the one-way clutch is used for a belt-type north drive unit of an automobile engine, which contributes to the elimination of a lock failure in a high-speed rotation range of the engine. can do.

According to the fourth aspect of the present invention, since the pulley on which the transmission belt is wound is provided on the outer periphery of the outer race, the effect of the third aspect of the invention can be properly obtained.

[Brief description of the drawings]

FIG. 1 is an enlarged side view showing a main part of a pulley with a built-in one-way clutch according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along line II-II of FIG.

FIG. 3 is a schematic diagram showing a serpentine-type accessory drive device of an automobile engine.

FIG. 4 is an enlarged view of a main part of a conventional one-way clutch, corresponding to FIG.

[Explanation of symbols]

Reference Signs List 1 inner ring 2 outer ring 3 pulley 4 retainer 5 sprag 6 leaf spring (pressing member) 8 guide surface 20 automobile engine 20a crankshaft 22 alternator (auxiliary machine) 22a alternator shaft (auxiliary machine shaft) 23 V-ribbed belt (transmission belt) A one direction Pulley with built-in clutch (one-way clutch) P Press point Q Contact point F ₁ Press force F ₂ Tilt power F ₃ Friction force L Reference line θ Sprag support angle

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hirofumi Miyata 3-2-15-1 Meiwadori, Hyogo-ku, Kobe-shi, Hyogo Inside Bando Chemical Co., Ltd. (72) Shinichiro Nishikawa 3-chome Meiwa-dori, Hyogo-ku, Kobe-shi, Hyogo No. 15 in Bando Kagaku Co., Ltd. (72) Inventor Masakazu Domoto 1578 Higashikaizuka, Iwata City, Shizuoka Prefecture Inside (72) Inventor Masahiko Soda 1578 Higashikaizuka, Iwata City, Shizuoka Prefecture Intranet Corporation

Claims (4)

[Claims] An inner ring; an outer ring mounted to the inner ring so as to be relatively rotatable; each being disposed between the inner and outer rings so as to be swingable in a plane orthogonal to a rotation axis of the inner and outer rings; A plurality of sprags that incline in the direction of biting into the inner and outer wheels to transmit torque between the inner and outer wheels while tilting in a direction in which they slide in contact with the inner and outer wheels to interrupt the torque transmission; A ring-shaped retainer which is provided and has a plurality of guide surfaces for slidably guiding the sprag when the corresponding sprag swings, and which is arranged concentrically between the inner and outer rings; A one-way clutch comprising a plurality of pressing members that constantly press the sprags so as to tilt in a direction of biting between the inner and outer rings while moving a contact point with the guide surface of the cage on the swing plane. And each of the above The tangential tilting force acting to tilt the sprag into the direction of biting between the inner and outer races at the contact point of the lug with the corresponding guide surface is smaller than the frictional force between the sprag and the guide surface acting on the contact point. A one-way clutch characterized by being set to be large. 2. The one-way clutch according to claim 1, wherein the sprag is made of steel, at least a guide surface of the retainer is formed of resin, and each pressing member moves the sprag in a direction perpendicular to the guide surface. On the swing plane of each of the sprags, the sprags are arranged so as to be constantly pressed against a reference line extending in a direction perpendicular to the guide surface from a pressing point where the sprags receive the pressing force of the pressing member. The sprag support angle formed by the straight line between the pressing point and the contact point is 12 °
A one-way clutch, characterized by being set as described above. 3. The one-way clutch according to claim 1, wherein the torque of the crankshaft rotating with a minute angular speed variation due to the explosion stroke of the vehicle engine is transmitted to the auxiliary shaft of the auxiliary through a transmission belt. A one-way clutch, which is disposed on a transmission path. 4. The one-way clutch according to claim 3, wherein a pulley for winding a transmission belt is provided on an outer periphery of the outer race.