JP2001082586A - Pulley device with built-in one-way clutch for alternator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To secure power generation efficiency of an alternator, prevent generation of abnormal noises, deterioration of life of an endless belt, and generation of fretting abrasion on support bearings. SOLUTION: Elastic constants of springs composing a one-way clutch 18, sliding resistance of seal rings 47, 47 against inner rings 45, 45, and rotational resistance of support bearings 41, 41 are respectively set to be specified values or lower. In order to relatively rotate a driven pulley 7a in the direction of overrunning in respect to a sleeve 8a, torque of 0.5 N.m or less is required.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pulley device with a built-in one-way clutch for an alternator, which is fixed to an end of a rotating shaft of an alternator as a generator for an automobile and fixed to an end of a crankshaft of an engine. It is used to drive the alternator by passing an endless belt between the pulleys.

[0002]

2. Description of the Related Art The structure of an alternator for generating electric power necessary for an automobile using an engine for driving the automobile as a driving source is described in, for example, Japanese Patent Application Laid-Open No. 7-139550. FIG. 4 shows an alternator 1 described in this publication. The rotating shaft 3 is rotatably supported inside the housing 2 by a pair of rolling bearings 4, 4. A rotor 5 and a commutator 6 are provided at an intermediate portion of the rotating shaft 3. A driven pulley 7 is provided at one end (right end in FIG. 4) of the rotating shaft 3 protruding outside the housing 2.
Is fixed. In an assembled state to the engine, an endless belt is stretched over the driven pulley 7, and the rotary shaft 3 is rotatably driven by the crankshaft of the engine.

Conventionally, the driven pulley 7 is generally
What was simply fixed to the rotating shaft 3 was used. On the other hand, in recent years, when the traveling speed of the endless belt is constant or increasing, transmission of power from the endless belt to the rotating shaft is freely performed, and when the traveling speed of the endless belt tends to decrease, Various pulley devices with a built-in one-way clutch for alternators, which make the relative rotation between the driven pulley and the rotary shaft freely, have been proposed and used in part. For example, JP-A-56-101353, JP-A-7-3
No. 17807, 8-61443, 10-
Japanese Patent Publication No. 285873, Japanese Patent Publication No. 7-72585, French Patent Publication FR2726059A1, and the like describe a pulley device with a built-in one-way clutch for an alternator having the above-described functions. In addition, such a pulley device with a built-in one-way clutch for an alternator is actually used.

[0004] FIG. 5 is a plan view of FIG.
No. 73 discloses a pulley device with a built-in one-way clutch for an alternator. This pulley device with a built-in one-way clutch for alternator
Has a sleeve 8 which can be externally fitted and fixed to the rotating shaft 3 (FIG. 4). The driven pulley 7a around the sleeve 8
Are arranged concentrically with the sleeve 8. A pair of support bearings 9 and 9 and a one-way clutch 10 are provided between the outer peripheral surface of the sleeve 8 and the inner peripheral surface of the driven pulley 7a.
Are provided. Among these, the support bearings 9, 9 support the radial load applied to the driven pulley 7a,
The relative rotation between the sleeve 8 and the driven pulley 7a is made free.

The one-way clutch 10 transmits the rotational force from the driven pulley 7a to the sleeve 8 only when the driven pulley 7a tends to rotate relative to the sleeve 8 in a predetermined direction. Be free. For this reason, a cam surface 12 is formed on the outer peripheral surface of the intermediate portion of the inner race 11 which is configured to form the one-way clutch 10 and is externally fitted and fixed to the sleeve 8. The cam surface 12 and the driven pulley 7a
A plurality of rollers 13 and 13 are arranged between the rollers 13 and 13. A plurality of springs (not shown) are provided between the rollers 13 and 13 and a retainer 14 for holding the rollers 13 and 13. Each of these springs is provided with a corresponding one of the rollers 13, 13 at the portion of the cylindrical gap formed between the cam surface 12 and the inner peripheral surface of the driven pulley 7 a having a reduced diameter. These rollers 13 and 13 are elastically pressed in a direction in which the rollers 13 and 13 are wedge-shaped. The torque for pressing the rollers 13 and 13 based on the elasticity is set to 4 Nm or less.

[0006] Japanese Patent Application Laid-Open No. H10-2858 constructed as described above
According to the alternator one-way clutch built-in type pulley device described in Japanese Patent Publication No. 73, the power generation efficiency of the alternator can be secured to some extent. That is, the rotational speed of the crankshaft constituting the engine increases, and the running speed of the endless belt 15 bridged between the driving pulley fixed to the end of the crankshaft and the driven pulley 7a tends to increase. Therefore, the driven pulley 7a tends to rotate relative to the sleeve 8 in a predetermined direction. As a result, the width of the rollers 13, 13 in the diametric direction of the cylindrical gap formed between the outer peripheral surface of the inner race 11 and the inner peripheral surface of the driven pulley 7a is reduced. The portion is wedge-shaped (locked) so that the rotational force can be freely transmitted from the driven pulley 7a to the rotary shaft 3. On the other hand, when the rotational speed of the crankshaft decreases and the running speed of the endless belt 15 tends to decrease, the driven pulley 7a
Relative to the predetermined direction. For this reason, each of the rollers 13, 13 moves to a portion of the cylindrical gap having a larger width, and each of the rollers 13, 13
13 is free to roll (overrun state) at this portion, and the relative rotation between the driven pulley 7a and the rotary shaft 3 is free. Since the transition to the overrun state is performed as described above, the rotation shaft 3 of the alternator can be continuously rotated in a certain high range based on its own rotational inertia force irrespective of the fluctuation of the rotation speed of the crankshaft. it can. For this reason, the power generation efficiency of the alternator can be secured to some extent.

[0007]

In the case of the pulley device with a built-in one-way clutch for an alternator described in Japanese Patent Application Laid-Open No. 10-285873, which is constructed and operates as described above, it is still not possible to ensure sufficient power generation efficiency. In addition, generation of abnormal noise due to friction between the driven pulley 7a and the endless belt 15 and a reduction in the life of the endless belt 15 may not be sufficiently prevented. That is, since the crankshaft is driven to rotate based on an intermittent explosion inside the cylinder of the engine, the crankshaft does not always rotate completely smoothly, and the rotation angular velocity fluctuates even during one rotation. Such fluctuations in the rotational angular velocity increase as the engine rotates at a lower speed. As a result, the endless belt 15 stretched over the drive pulley fixed to the end of the crankshaft.
The running speed of the vehicle also fluctuates finely. Therefore, in order to sufficiently secure the power generation efficiency of the alternator, the pulley device is made to follow such a small variation in the traveling speed of the endless belt 15, and when the traveling speed of the endless belt 15 tends to decrease, The transition from the lock state to the overrun state needs to be performed promptly.

On the other hand, even if the running speed of the endless belt 15 fluctuates finely, the rotating shaft 3 of the alternator driven to rotate by the endless belt 15 via the driven pulley 7a.
Does not fluctuate so rapidly based on the rotational inertia of the rotary shaft 3 itself and the rotor 5 and the commutator 6 fixed to the rotary shaft 3. Therefore, the inner peripheral surface of the endless belt 15 and the outer peripheral surface of the driven pulley 7a tend to rub in both directions. As a result, stresses in different directions are repeatedly applied to the endless belt 15 that rubs against the driven pulley 7a, and a slip occurs between the endless belt 15 and the driven pulley 7a, and abnormal noise is easily generated by the slip. Or the life of the endless belt 15 may be shortened.

The endless belt 1 based on the friction between the outer peripheral surface of the driven pulley 7a and the inner peripheral surface of the endless belt 15 as described above.
Actually, the reduction in the service life of 5 also occurs by repeating acceleration and deceleration during traveling. That is, during acceleration, the endless belt 15
While the driving force is transmitted from the side to the driven pulley 7a side, the braking force from the endless belt 15 acts on the driven pulley 7a that continues to rotate based on inertia as described above during deceleration. Since the braking force and the driving force act as frictional forces on the inner peripheral surface of the endless belt 15 in the opposite direction, the braking force and the driving force also cause a reduction in the life of the endless belt 15. In particular, in the case of a vehicle equipped with an exhaust brake like a truck, the deceleration of the decrease in the rotation of the crankshaft when the accelerator is off is remarkable, and the friction applied to the inner peripheral surface of the endless belt 15 based on the braking force As a result of an increase in force, the above-mentioned life is significantly reduced.

[0010] In order to solve the various disadvantages as described above, it has been conventionally conceived to use a pulley incorporating a one-way clutch as a pulley for the alternator. In the case of the structure described in Japanese Unexamined Patent Application Publication No. 10-285873, the torque for pressing the rollers 13 constituting the one-way clutch 10 in a predetermined direction is as large as 4 N · m or less. For this reason, the structure described in the above-mentioned Japanese Patent Application Laid-Open No. 10-285873 can cope with a relatively large fluctuation of the rotation speed of the engine, but does not cope with a small fluctuation of the rotation angular velocity that occurs during one rotation of the crankshaft. It may not be possible to respond. If the pulley device cannot be made to cope with the minute fluctuation of the rotational angular velocity of the crankshaft in this way, the rotation of the rotating shaft 3 of the alternator cannot always be maintained in a high rotation range, and as described above, the driven pulley 7a and the Stresses in different directions repeatedly act on the rubbing endless belt 15. As a result, sufficient power generation efficiency of the alternator
Alternatively, generation of abnormal noise due to slippage between the endless belt 15 and the driven pulley 7a and a reduction in the life of the endless belt 15 may not be sufficiently prevented.

In the case of the pulley device with a built-in one-way clutch for an alternator described in the above-mentioned Japanese Patent Application Laid-Open No. 10-285873, the rollers 13 constituting the one-way clutch 10 are formed in order to secure power generation efficiency. Focusing only on the magnitude of the torque for pressing in a predetermined direction, this torque value is set to 4 N · m or less. However, when the traveling speed of the endless belt 15 tends to decrease and the driven pulley 7a needs to be rotated in the direction of overrun with respect to the rotating shaft 3 of the alternator, the resistance to this rotation is as follows. Actually, not only the torque for pressing the rollers 13 and 13 in a predetermined direction but also the rolling resistance of the support bearings 9 and 9 provided on both sides of the one-way clutch 10 and the support bearings 9 and 9 And the like, there is a sliding resistance of a seal member provided between the driven pulley 7a and the sleeve 8 due to the attachment to the end or the like. Therefore, Japanese Patent Application Laid-Open No. 10-285
In the case of the conventional structure described in Japanese Unexamined Patent Publication No. 873, the torque required to rotate the driven pulley 7a relative to the rotating shaft 3 of the alternator in the direction of the overrun state is actually larger than 4 Nm. . When the torque is increased in this way, the torque that resists the rotation in the direction of the overrun state suppresses the rotation based on the rotational inertia of the rotating shaft 3 and the like, so that the power generation efficiency of the alternator is reduced. It becomes even more difficult to secure enough, or to sufficiently prevent the generation of abnormal noise due to slippage between the endless belt 15 and the driven pulley 7a and the reduction in the life of the endless belt 15.

In the structure described in JP-A-10-285873, if ball bearings are used as the support bearings 9, 9, not only the radial load applied from the endless belt 15 but also the driven pulley 7a The thrust load applied to the driven pulley 7a can be supported based on the mounting error of the driven pulley 7a. Therefore, unlike the structure using a radial needle bearing as each of the support bearings 9 and 9, there is no need to attach another bearing to support the thrust load, and the structure is inexpensive. However, in the case of a structure using ball bearings as the support bearings 9, 9, the contact surfaces between the rolling surfaces of the balls constituting the support bearings 9, 9 and the inner raceway and the outer raceway are pointed. Be in touch. And
If each of the support bearings 9, 9 cannot cope with a minute fluctuation of the rotation speed occurring during one rotation of a crankshaft having a drive pulley for driving the endless belt 15 fixed to an end thereof, the contact portion will not work. Under high surface pressure,
While receiving the vibration of the engine, the balls and the inner ring and the outer ring rotate integrally. As a result, fretting wear occurs at the contact portions between the rolling surfaces of these balls and the inner raceway and the outer raceway, and the support bearings 9, 9
However, it cannot be used early.

The use of a ball bearing incorporating a large-diameter ball as each of the support bearings 9 can solve the above-mentioned problem to some extent. However, in the case of a pulley device with a built-in one-way clutch for an alternator, which is an object of the present invention, the support bearings 9 and 9 are installed in a limited mounting space.
When ball bearings are used as the support bearings 9 and 9, it is difficult to reduce the contact surface pressure at the contact portion between the rolling surface of each ball and the inner raceway and outer raceway. is there. On the other hand, each of the support bearings 9,
When a radial needle bearing is used as 9, the contact portions between the rolling surfaces of the needles forming these support bearings 9 and 9 and the inner raceway and the outer raceway are in line contact. The contact surface pressure of the contact portion can be reduced as compared with the structure using the ball bearing. Therefore, even if it is not possible to cope with the minute fluctuation of the rotation speed generated during one rotation of the crankshaft, the fretting wear generated at the contact portion is slight and does not cause any problem. However, when a radial needle bearing is used as the support bearings 9, 9, the support bearings 9, 9 cannot support a thrust load. The problem is that such a bearing is required. In view of the above-described circumstances, the present invention has a structure that can be obtained at a low cost by using a ball bearing as a support bearing, while ensuring the power generation efficiency of the alternator, generating abnormal noise, and reducing the life of the endless belt. The present invention has been made in order to sufficiently prevent the occurrence of fretting wear on the components of the support bearing.

[0014]

A pulley device with a built-in one-way clutch for an alternator according to the present invention is, similarly to a conventionally known pulley device with a built-in one-way clutch for an alternator, externally fixed to a rotating shaft of the alternator. A free sleeve, a driven pulley disposed concentrically with the sleeve around the sleeve, and provided between an axial intermediate portion of an outer peripheral surface of the sleeve and an axial intermediate portion of an inner peripheral surface of the driven pulley; A one-way clutch that enables the transmission of rotational force between the driven pulley and the sleeve only when the driven pulley tends to rotate relative to the sleeve in a predetermined direction; In the state of sandwiching,
A pair of support bearings are provided between the outer peripheral surface of the sleeve and the inner peripheral surface of the driven pulley to support a radial load applied to the driven pulley and allow relative rotation between the sleeve and the driven pulley. .

In particular, in the pulley device with a built-in one-way clutch for an alternator according to the present invention, each of the above-mentioned support bearings is a ball bearing capable of supporting a thrust load in addition to a radial load. At the same time, the torque required to rotate the driven pulley relative to the sleeve in the direction opposite to the predetermined direction is set to 0.5 Nm or less.
More preferably, the torque is set to 0.3 Nm or less.

[0016]

In the pulley device with a built-in one-way clutch for an alternator according to the present invention constructed as described above, the torque required for rotating the driven pulley relative to the sleeve in the direction opposite to the predetermined direction is 0.5 N · m or less (preferably 0.3
N · m or less). For this reason, when the running speed of the endless belt stretched over the driven pulley tends to decrease sufficiently in response to the minute fluctuation of the rotational angular speed occurring during one rotation of the crankshaft of the engine, The relative rotation between the driven pulley and the rotating shaft of the alternator can be made freely. As a result, according to the present invention,
In addition to securing the power generation efficiency of the alternator, preventing the generation of abnormal noise and reducing the life of the endless belt, and also preventing the occurrence of fretting wear on the components of the support bearings, each of which is a ball bearing. We can plan enough.

Next, an experiment conducted by the inventor of the present invention will be described in order to clarify the basis for obtaining the above-mentioned effects by the pulley device incorporating a one-way clutch for an alternator of the present invention. . First, in conducting this experiment, in a pulley device with a built-in one-way clutch for an alternator having a structure generally used conventionally, the driven pulley is moved in a direction opposite to a predetermined direction with respect to the sleeve (a direction in which an overrun occurs). Four types were prepared in which the minimum torque required for relative rotation was changed in the range of 0.3 to 0.6 N · m. The experiment was performed by using a strobe to check whether each pulley device can follow the fine fluctuation of the rotation angular velocity generated during one rotation of the crankshaft while changing the tension of the endless belt. . or,
The rotation speed of the driven pulley was 11,500 ± 80 rpm. The fluctuation of the rotational angular velocity occurring during one revolution of the crankshaft was given by providing a universal joint between the driving pulley and a driving shaft for driving the driving pulley. The current load of the alternator was set to 50A. The results of the experiments performed in this way are shown in Table 1 below.

[0018]

[Table 1]

In Table 1, ○ indicates that the pulley device was able to follow the fluctuation of the rotational angular velocity generated during one rotation of the crankshaft, and the relative rotation between the driven pulley and the sleeve occurred. X indicates that the pulley device could not follow the fluctuation of the rotational angular velocity, and no relative rotation between the driven pulley and the sleeve occurred.
As can be seen from the experimental results shown in Table 1, when the tension of the endless belt is set at 686 N (= 70 kgf), the driven pulley must be sleeved so that the pulley device can follow the fluctuation of the rotational angular velocity. The torque required for relative rotation in the direction of overrun
・ Must be set to m or less. Generally, the endless belt tension is set at about 686 N (= 70 kgf). On the other hand, in the case of an actual automobile engine, even if the tension of the endless belt is initially set at 686 N (= 70 kgf), the tension of the endless belt is changed due to a temporal change such as permanent deformation of the endless belt itself. About 294N (=
30 kgf). Accordingly, even if the tension of the endless belt is reduced to 294 N (= 30 kgf), it is preferable that the pulley device can follow the fluctuation of the rotational angular velocity. As can be seen from the experimental results shown in Table 1,
Even when the tension of the endless belt becomes 294 N (= 30 kgf), the driven pulley is relatively rotated with respect to the sleeve in the overrun state so that the pulley device can follow the fluctuation of the rotational angular velocity. It is necessary to set the necessary torque to 0.3 N · m or less.

In the pulley device with a built-in one-way clutch for an alternator according to the present invention, the torque required for rotating the driven pulley relative to the sleeve in the overrun state is 0.5 Nm as described above. Since it is smaller than the following, at the time of use, relative rotation always occurs between the driven pulley and the sleeve. For this reason, the contact position of the rolling surface of the ball which comprises each support bearing with the inner raceway and the outer raceway changes constantly. As a result, based on the large radial load applied to the driven pulley from the endless belt, even if the contact surface pressure of the contact portion between the rolling surface of the balls constituting each of the support bearings and the inner raceway and the outer raceway is high, Fretting wear does not occur on each track, and the durability of each of the support bearings, which are ball bearings, is improved. On the other hand, in the case of a pulley device having a large overrun torque such that the torque required to relatively rotate the driven pulley relative to the sleeve in a direction of overrun exceeds 0.5 Nm, the average angular velocity However, under certain operating conditions, even if there is a small angular velocity fluctuation synchronized with the explosion cycle of the engine, the contact position between the rolling surface of each ball constituting each of the above support bearings and the inner raceway and the outer raceway does not change much. ,
Each of these balls and the inner ring and the outer ring rotate integrally. At this time, the contact portion between the rolling surface of each ball and the inner raceway and the outer raceway rotates under a high surface pressure while receiving micro vibration transmitted from an engine or the like. As a result, the inner ring raceway and the outer raceway fretting wear occur, and sufficient durability cannot be obtained.

As can be seen from the above experimental results, in the case of the present invention, the structure obtained at a low cost by using a ball bearing as the support bearing has a small rotation angular velocity generated during one rotation of the crankshaft. It can cope with fluctuations. As a result, while maintaining the power generation efficiency of the alternator, generation of abnormal noise and reduction of the life of the endless belt are prevented,
Further, it is possible to sufficiently prevent the occurrence of fretting wear on the components of the support bearing.

[0022]

1 and 2 show a first embodiment of the present invention. The one-way clutch built-in pulley device for the alternator of the present example is formed in a cylindrical shape as a whole,
The alternator includes a sleeve 8a externally fitted and fixed to the end of the rotating shaft 3 (see FIG. 4) of the alternator, and a driven pulley 7a disposed around the sleeve 8a and concentrically with the sleeve 8a. The sleeve 8a is rotatable with the rotation shaft 3. For this reason, in the illustrated example, the sleeve 8
A female spline portion 16 is formed on the inner peripheral surface of the intermediate portion a, and the female spline portion 16 and a male spline portion (not shown) formed on the outer peripheral surface of the end portion of the rotary shaft 3 are freely engageable. The structure for preventing the relative rotation between the rotary shaft 3 and the sleeve 8a may be replaced with a screw, a fitting between non-cylindrical surfaces, a key engagement, or the like instead of the spline.

The driven pulley 7a provided around the sleeve 8a has a support bearing 41 described below inside thereof.
41 and the one-way clutch 18 are mounted. A plurality of (four in this example) concave grooves 19, 19 each having a V-shaped cross section, are formed on the outer peripheral surface of the driven pulley 7a in parallel with each other and over the entire circumference. Has formed. Between the driven pulley 7a and a driving pulley (not shown), an endless end formed by forming a plurality of (four in the present example) ribs on the inner peripheral surface and having a V-shaped cross section and continuous over the entire periphery. Belt 15
(See FIG. 5).

A pair of support bearings 41, each of which is a deep groove type ball bearing, is provided between the outer peripheral surface of the sleeve 8a configured as described above and the inner peripheral surface of the driven pulley 7a configured as described above. 41 and one one-way clutch 18 which is a roller clutch. A pair of the support bearings 41, 41 includes an outer ring 43 having a deep groove type outer raceway 42 on the inner peripheral surface and a deep groove type inner raceway 4 on the outer peripheral surface.
, The outer raceway 42 and the inner raceway 4
4 and a plurality of balls 46 each of which is provided so as to freely roll.
And a pair of seal rings 4 provided between a bearing retainer 33 that rotatably holds each of the balls 46 and an inner peripheral surface of both ends of the outer ring 43 and an outer peripheral surface of both ends of the inner ring 45.
7, 47. Each such support bearing 41, 4
1 is that each outer ring 43 is internally fitted and fixed to a portion near both ends of the inner peripheral surface of the driven pulley 7a by interference fit, and each inner ring 45 is externally fitted and fixed to a portion near both ends of the outer peripheral surface of the sleeve 8a by interference fit. As a result, the sleeve 8
a of the driven pulley 7a is provided between both ends of the driven pulley 7a. The seal rings 47, 47 have their respective outer peripheral edges fixed to the inner peripheral surfaces of the ends of the respective outer races 43, and their respective inner peripheral edges are slidably contacted with the outer peripheral surfaces of the ends of the respective inner races 45. .

The one-way clutch 18 is provided between the intermediate portion of the outer peripheral surface of the sleeve 8a and the intermediate portion of the inner peripheral surface of the driven pulley 7a. The outer race 48 for the one-way clutch constituting the one-way clutch 18 is separate from the outer races 43, 43 constituting the pair of support bearings 41, 41. Then, the inner side surfaces of the outer ring side flange portions 27a and 27b provided at both axial ends of the one-way clutch outer ring 48 face the end surfaces of the clutch retainer 30, respectively. Further, in order to constitute the one-way clutch 18, the one-way clutch inner ring 20 is externally fitted and fixed to the outer peripheral surface of the intermediate portion of the sleeve 8a by interference fitting. The one-way clutch inner race 20 is formed entirely of a hard metal plate material such as bearing steel or a carburized steel plate material such as SCM415 into a cylindrical shape, and the outer peripheral surface is a cam surface 21 described below.

The one-way clutch 18 includes an inner peripheral surface of an intermediate portion of the outer race 48 for the one-way clutch and an outer peripheral surface of the inner race 20 for the one-way clutch.
That is, at one or more locations on the outer peripheral surface of the one-way clutch inner ring 20, called a ramp portion, the depth is one end in the circumferential direction (FIG. 2).
To the right) of the one-way clutch inner ring 20 in the axial direction.
The cam ring 21 is formed at regular intervals in the circumferential direction, and the outer peripheral surface of the one-way clutch inner ring 20 is the cam surface 21. A cylindrical gap 28 is formed between the outer peripheral surface of the one-way clutch inner race 20 and the inner peripheral surface of the one-way clutch outer race 48. The cross-sectional height dimension of the outer ring 48 for the directional clutch in the diametrical direction is determined by the plurality of rollers 2 disposed in the cylindrical gap 28 at the portions corresponding to the recesses 25.
9 is smaller than the outer diameter of each of the rollers 29 at portions deviating from these recesses 25.

The one-way clutch 18 is formed in a cage type cylindrical shape with a synthetic resin between the inner peripheral surface of the intermediate portion of the outer race 48 for the one-way clutch and the outer peripheral surface of the inner race 20 for the one-way clutch. A clutch retainer 30 and a plurality of rollers 29 and springs 39, 39 are provided. Among them, the clutch retainer 30 is provided inside the outer ring 48 for the one-way clutch, and the convex portion 3 formed on the inner peripheral surface thereof.
The first and one-way clutches are engaged with the concave portions 25 and 25 formed on the outer peripheral surface of the one-way clutch inner ring 20 so that the one-way clutch inner ring 20 cannot be rotated relative to the one-way clutch inner ring 20. Further, one side in the axial direction of the clutch retainer 30 is opposed to the inner side surfaces of the outer ring side flange portions 27a and 27b provided at both axial end portions of the one-way clutch outer ring 48,
The clutch retainer 30 is prevented from shifting in the axial direction. The plurality of rollers 29 are held inside the pockets 32, 32 formed in the clutch retainer 30 so as to be able to roll and slightly displace in the circumferential direction.

The springs 39 are provided between the pillars 40 and 40 constituting the clutch retainer 30 as described above and the rollers 29, respectively. Are elastically pressed in the same direction (left direction in FIG. 2). Generally, each of the springs 39 is a plate spring made of stainless steel formed by pushing a band-shaped spring plate back into a U-shape or a M-shape, or a synthetic resin spring formed integrally with the retainer.

Particularly, in the case of the pulley device with a built-in one-way clutch for an alternator according to the present invention, the torque required to rotate the driven pulley 7a relative to the sleeve 8a in a direction in which the sleeve 8a is overrun is set to about 0. 25N ・ m
(0.5 N · m or less). For this reason, in the case of this example, the elastic constants of the springs 39, 39 constituting the one-way clutch 18, the sliding resistance of the pair of seal rings 47, 47 with the inner rings 45, 45, and the pair of The rolling resistance of each of the support bearings 41 is set to a predetermined value or less. For this reason, in the case of this example, in order to reduce the sliding resistance of the pair of seal rings 47, 47, the inner rings 45 at the leading edges of the seal lips of the elastic material constituting the seal rings 47, 47 are used. , 45 is restricted to a range of about 0 to 0.2 mm.

In the pulley device with a built-in one-way clutch for an alternator of the present invention constructed as described above, the one-way clutch 18 is provided between the driven pulley 7a in which the one-way clutch outer ring 48 is fixedly fitted and the rotary shaft 3. Transmits only the rotational force in a predetermined direction. For example, in FIG.
Is fixed and only the one-way clutch outer ring 48 rotates, and when the one-way clutch outer ring 48 rotates clockwise in FIG. Based on the force received from the peripheral surface, each of the concave portions 25 tends to be displaced toward the deeper side against the elasticity of each spring 39. Then, each of the rollers 29 becomes rotatable in the cylindrical gap 28, and the transmission of rotational force between the one-way clutch outer ring 48 and the one-way clutch inner ring 20 is stopped. , A so-called overrun state. Conversely, when the one-way clutch outer ring 48 rotates in the counterclockwise direction in FIG.
As shown by a two-dot chain line in FIG. 2, based on the force received from the inner peripheral surface of
The one-way clutch outer ring 48 and the one-way clutch inner ring 20 are integrally connected to each other, and the one-way clutch outer ring 48 and the one-way clutch outer ring 48 are integrally connected to each other.
A so-called locked state in which the torque can be freely transmitted between the motor and the one-way clutch inner ring 20.

In the case of the present invention, the driven pulley 7
The torque required to rotate the a relative to the sleeve 8a in the direction in which the sleeve 8a is overrun is about 0.25 N · m
And small. Therefore, if the predetermined direction is made appropriate with respect to the rotation direction of the crankshaft, the transmission of the rotational force from the driven pulley 7a to the rotary shaft 3 is performed when the rotational speed of the crankshaft is constant or tends to increase. When the rotational speed of the crankshaft tends to decrease, the relative rotation between the driven pulley 7a and the rotary shaft 3 can be freely adjusted, and the overrun state can be achieved. As a result, irrespective of the fluctuation of the rotation speed of the crankshaft, the rotation of the alternator is maintained at a sufficiently high frequency to secure the power generation efficiency, and the driven pulley 7a
The occurrence of abnormal noise due to the slippage between the endless belt 15 and the driven pulley 7a and the shortening of the life of the endless belt 15 can be prevented.

Further, in the case of this embodiment, the driven pulley 7
a required torque to rotate the sleeve 8a relative to the sleeve 8a in a direction in which the sleeve 8a is in an overrun state.
・ M is small. For this reason, when the running speed of the endless belt 15 tends to decrease sufficiently in response to minute fluctuations in the rotational angular speed occurring during one revolution of the crankshaft of the engine, the driven pulley 7a The relative rotation with respect to the rotating shaft 3 can be freely set, and an overrun state can be set. As a result, according to the present invention, it is possible to cope with not only the fluctuation of the rotation speed of the engine but also the fine fluctuation of the rotation angular speed, thereby securing the power generation efficiency of the alternator, generating abnormal noise, and controlling the endless belt. Can be prevented from being shortened. Further, the support bearings 41, 4
The fretting wear of the outer raceway 42 and the inner raceway 44 of the outer race 43 and the inner race 45 constituting the first race 1 can be sufficiently prevented. In particular, in the case of the present embodiment, it is easy to cope with small fluctuations in the rotational angular velocity of the crankshaft, and the tension of the endless belt 15 (see FIG. 5) is set to about 294 N (30 kgf).
In this case, even when the rotation speed decreases, the alternation of the rotational angular velocity is followed to secure the power generation efficiency of the alternator, to prevent the generation of abnormal noise, to reduce the life of the endless belt 15, and to prevent the occurrence of fretting wear. Everything can be done sufficiently. As is clear from Table 1 above, if the tension of the endless belt 15 can be maintained higher, the torque required for relative rotation in the direction of the overrun state is reduced from the above-mentioned 0.25 N · m. Somewhat high (but 0.
5 N · m or less).

Next, FIG. 3 shows a second embodiment of the present invention.
An example is shown. In the case of this example, unlike the case of the above-described first example, each support bearing 41a, 41a is provided with a seal ring 47 only at one end near the axial end of the driven pulley 7a and the sleeve 8b. ing. Therefore,
In the case of this example, the seal ring 47 in the entire pulley device is used.
And the torque required to rotate the driven pulley 7a relative to the sleeve 8b in the direction of overrun with respect to the sleeve 8b by about 0.20 N · m (0.3
N · m or less), which can be further reduced as compared with the case of the first example described above.

Therefore, according to the structure of this embodiment, even when the tension of the endless belt 15 (see FIG. 5) is further reduced below about 294 N (= 30 kgf), it follows small fluctuations in the rotational angular velocity of the crankshaft. In addition to ensuring the power generation efficiency of the alternator, preventing generation of abnormal noise and shortening of the life of the endless belt 15, furthermore, fretting wear on the outer raceway 42 and the inner raceway 44 of the outer race 43 and the inner race 45 constituting the support bearings 41a, 41a. Can be sufficiently prevented from occurring.

In the case of the present embodiment, small diameter portions 49, 49 are formed on the outer peripheral surfaces of both ends of the sleeve 8b. When the inner races 45 constituting the support bearings 41a, 41a are externally fitted and fixed to the outer peripheral surface of the sleeve 8b by interference fit, the inner races 45 are fixed.
The one end face of the small diameter portions 49, 49 and the central large diameter portion 51.
The support bearings 41a, 41a are prevented from slipping in the axial direction with respect to the sleeve 8b by abutting against the step portions 50, 50 which are continuous portions of the support bearings 41a, 41a. Other configurations and operations are the same as those of the first example described above, and therefore, the same parts are denoted by the same reference numerals, and redundant description will be omitted.

In each of the above embodiments, the one-way clutch has been described as a roller clutch using rollers as a plurality of lock members. However, the present invention is not limited to such a structure, and may be applied to a structure in which the one-way clutch is a sprag-type one-way clutch using sprags as a plurality of lock members.

[0037]

The pulley device with a built-in one-way clutch for an alternator according to the present invention is constructed and operated as described above, so that the power generation efficiency of the alternator is ensured, the generation of abnormal noise and the shortening of the life of the endless belt are reduced. This can sufficiently prevent the occurrence of fretting wear on the constituent members of the support bearings, each of which is a ball bearing. As a result, it is possible to reduce the size and cost of the alternator incorporating the pulley device and to improve the durability.

[Brief description of the drawings]

FIG. 1 is a half sectional view showing an example of an embodiment of the present invention.

FIG. 2 is a sectional view taken along the line AA of FIG. 1, showing only the one-way clutch.

FIG. 3 is a half sectional view showing a second example of the embodiment of the present invention.

FIG. 4 is a sectional view showing an example of a conventionally known alternator.

FIG. 5 is a cross-sectional view showing an example of a conventionally known pulley device with a built-in one-way clutch for an alternator.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Alternator 2 Housing 3 Rotating shaft 4 Rolling bearing 5 Rotor 6 Commutator 7, 7a Followed pulley 8, 8a, 8b Sleeve 9 Support bearing 10 One-way clutch 11 Inner ring 12 Cam surface 13 Roller 14 Cage 15 Endless belt 16 Female spline part Reference Signs List 18 one-way clutch 19 concave groove 20 one-way clutch inner ring 21 cam surface 25 concave portion 27a, 27b outer ring side flange portion 28 cylindrical gap 29 roller 30 clutch retainer 31 convex portion 32 pocket 33 bearing retainer 39 spring 40 column Part 41, 41a Support bearing 42 Outer raceway 43 Outer raceway 44 Inner raceway 45 Inner raceway 46 Ball 47 Seal ring 48 One-way clutch outer raceway 49 Small diameter part 50 Step part 51 Large diameter part

Claims (1)

[Claims] 1. A sleeve which can be externally fitted and fixed to a rotating shaft of an alternator, a driven pulley disposed around the sleeve and concentric with the sleeve, an axially intermediate portion of an outer peripheral surface of the sleeve, and an inner periphery of the driven pulley. Between the driven pulley and the sleeve only when the driven pulley tends to rotate relative to the sleeve in a predetermined direction. The one-way clutch is provided between the outer peripheral surface of the sleeve and the inner peripheral surface of the driven pulley in a state where the one-way clutch is sandwiched from both sides in the axial direction, and is driven by these sleeves while supporting the radial load applied to the driven pulley. In a pulley device with a built-in one-way clutch for an alternator having a pair of support bearings capable of rotating relative to a pulley, these support bearings are radially loaded. In addition to the above, a ball bearing capable of freely supporting a thrust load and a torque required for rotating the driven pulley relative to the sleeve in a direction opposite to the predetermined direction are set to 0.5 Nm or less. A one-way clutch built-in pulley device for alternators.