JP2005256884A - Pulley device incorporating one-way clutch - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To secure durability by setting load capacity of a one-way clutch high, and restrict cost low. <P>SOLUTION: This device 20 is provided between an outer circumferential surface of a sleeve 22 and an inner circumferential surface of a pulley 23, and it is provided with the one-way clutch 25 having a recessed cam surface 27 to transmit torque between the pulley 23 and the sleeve 22 only in a case where the pulley 23 and the sleeve 22 are tend to be relatively rotated in prescribed directions. The cam surface 27 in the one-way clutch 25 is formed in an outer circumferential surface of an inner ring 26 engaged with the sleeve 22. For material of the inner ring 26 having the cam surface 27, quenched and tempered steel is used. The cam surface 27 is formed by drawing or rolling. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a pulley device with a built-in one-way clutch, for example, an endless belt is stretched between a rotating pulley of an alternator that is a generator for an automobile and a driving pulley attached to a crankshaft of an engine. It is related with the pulley apparatus with a built-in roller clutch for alternators used in order to drive an alternator.

As an alternator for generating power necessary for an automobile using an automobile engine as a drive source, for example, the one shown in FIG. 3 is known (see, for example, Patent Document 1).
In this alternator 1, a rotary shaft 3 is rotatably supported in a housing 2 via a pair of rolling bearings 4, and a rotor 5 and a commutator 6 are disposed in an intermediate portion in the axial direction of the rotary shaft 3. Has been. Further, a driven pulley 7 is attached to an end portion (the right end portion in FIG. 1) of the rotating shaft 3 that protrudes from the housing 2, and in the assembled state to the engine, the driven pulley 7 and a drive attached to the crankshaft of the engine. An endless belt is spanned between the pulley and the rotation shaft 3 is driven to rotate through the drive pulley, the endless belt and the driven pulley 7 by driving the crankshaft.

  By the way, as an alternative to the driven pulley 7 in recent years, when the travel speed of the endless belt is constant or tends to increase, power is transmitted from the endless belt to the rotating shaft, and the travel speed of the endless belt tends to decrease. In this case, a pulley device with a built-in clutch for an alternator that allows relative rotation between a driven pulley and a rotating shaft has been proposed (see, for example, Patent Documents 2 to 5).

  FIG. 4 shows a pulley device with a built-in clutch for an alternator disclosed in Patent Document 3. This pulley device with a built-in clutch for an alternator has a sleeve 8 in which the rotary shaft 3 is fitted. . A driven pulley 7a is disposed concentrically with the sleeve 8 around the sleeve 8, and a pair of support bearings 9a 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. It has been.

  The support bearing 9a supports the radial load applied to the driven pulley 7a while allowing the sleeve 8 and the driven pulley 7a to rotate relative to each other. The one-way clutch 10 allows the driven pulley 7a to move relative to the sleeve 8 in a predetermined direction. Only when it tends to rotate, the rotational force is transmitted from the driven pulley 7a to the sleeve 8.

The reason for using such a pulley device with a built-in clutch for the alternator is as follows.
For example, when the engine is a diesel engine, the fluctuation of the rotational angular velocity of the crankshaft becomes large at low speeds such as idling. As a result, the endless belt 11 stretched between the drive pulley attached to the crankshaft and the driven pulley 7a. The traveling speed will also vary finely.

  On the other hand, the rotation of the rotating shaft 3 of the alternator 1 that is rotationally driven by the endless belt 11 via the driven pulley 7a is so rapidly caused by the inertial mass of the rotating shaft 3, the rotor 5 fixed to the rotating shaft 3, the commutator 6, and the like. Does not fluctuate. Therefore, when the driven pulley 7a is simply fixed to the rotating shaft 3, the endless belt 11 and the driven pulley 7a tend to rub against each other as the crankshaft changes in angular velocity. As a result, repeated stress is applied to the endless belt 11 in different directions, and slipping is likely to occur between the endless belt 1 and the driven pulley 7a, or the life of the endless belt 11 may be shortened.

  Such a decrease in the life of the endless belt 11 is also caused by repeated acceleration / deceleration during traveling. That is, while the driving force is transmitted from the endless belt 11 to the driven pulley 7a during acceleration, the braking force is applied from the endless belt 11 to the driven pulley 7a that continues to rotate based on inertia as described above during deceleration. Works.

  Since the braking force and the driving force act as a frictional force in the opposite direction against the inner peripheral surface of the endless belt 11, the life of the endless belt 11 is reduced. In particular, in the case of a vehicle equipped with an exhaust brake such as a truck, the deceleration of the decrease in rotation of the crankshaft when the accelerator is off is significant, and the frictional force applied to the inner peripheral surface of the endless belt 11 based on the braking force is As a result of the increase, the service life is significantly reduced.

  Therefore, by adopting the above-described pulley device with a built-in clutch for the alternator, when the traveling speed of the endless belt 11 tends to be constant or rising, the rotational force is transmitted from the driven pulley 7a to the rotating shaft 3, and On the other hand, the rotational angular velocity of the driven pulley 7a is made slower than the rotational angular velocity of the rotary shaft 3 to prevent the contact portion between the endless belt 11 and the driven pulley 7a from rubbing strongly. In this way, the direction of the stress acting on the rubbing portion between the driven pulley 7a and the endless belt 11 is made constant, slippage occurs between the endless belt 11 and the driven pulley 7a, and the life of the endless belt is reduced. To prevent that.

  When a roller clutch is used as the one-way clutch 10 of the pulley device with a built-in clutch for the above-described alternator, a concave cam surface extending in the circumferential direction is formed on the inner peripheral surface of the outer ring or the outer peripheral surface of the inner ring constituting the roller clutch. There is a need to. An outer ring or an inner ring having such a cam surface is conventionally manufactured by pressing, and the outer ring is fitted into the driven pulley 7 a and the inner ring is fitted into the sleeve 8.

  By the way, when the outer ring or the inner ring is manufactured by pressing, the material cost and the processing cost are low, so that the outer ring or the inner ring can be obtained at a low cost. The peripheral surface of the roller is recessed in the diameter direction from the peripheral surface of the central portion, and since the recessed portion does not contact the rolling surface of the roller, the contact area is reduced, the load capacity of the roller clutch is reduced, and the durability is There arises a problem that the roller is skewed or roller skew is likely to occur.

Therefore, in order to solve such problems, the outer ring or inner ring forming the cam surface is manufactured by drawing to avoid sagging at both ends in the axial direction, thereby increasing the load capacity of the roller clutch. A pulley apparatus with a built-in roller clutch for an alternator that ensures durability is proposed (see, for example, Patent Document 6).
JP-A-7-139550 JP-A-56-101353 JP-A-8-61443 Japanese Patent Publication No.7-72585 French Patent Publication FR2726059A1 Japanese Patent Laid-Open No. 11-118025

  However, in the above-mentioned Patent Document 6, since low and medium carbon steel such as steel for cold rolling or chrome molybdenum steel is used as the material of the outer ring or inner ring, in order to give the necessary hardness to the product, There is a need for surface hardening heat treatment represented by carburizing, carbonitriding, induction hardening, etc., which tends to be expensive, and it also takes time in terms of product management (management of depth of hardened layer, etc.) There is.

  The present invention has been made in view of the circumstances as described above, and an object of the present invention is to increase the load capacity of the one-way clutch to ensure durability and to reduce the cost. An object is to provide a pulley device with a built-in directional clutch.

A pulley apparatus with a built-in one-way clutch according to the present invention includes a sleeve in which a rotation shaft is fitted, a pulley disposed concentrically with the sleeve outside the sleeve, an outer circumferential surface of the sleeve, and an inner circumferential surface of the pulley. A one-way clutch having a concave cam surface that transmits a rotational force between the pulley and the sleeve only when the pulley and the sleeve tend to rotate relative to each other in a predetermined direction. The pulley and the sleeve are provided between the outer peripheral surface of the sleeve and the inner peripheral surface of the pulley at a position spaced apart in the axial direction with respect to the one-way clutch, while supporting a radial load applied to the pulley. A support bearing that enables relative rotation of the one-way clutch, and the outer peripheral surface of the inner ring that is externally fitted to the sleeve or the inner ring of the outer ring that is fitted to the pulley. A built-in one-way clutch pulley device formed on,
The material of the outer ring or inner ring forming the cam surface is made of steel that has been subjected to a quenching process or a marshalling process, and the cam surface is formed by drawing or rolling.

  The pulley apparatus with a built-in one-way clutch according to the present invention is characterized in that the one-way clutch is a roller clutch.

  The pulley device with a built-in one-way clutch configured as described above uses steel that has been subjected to a quenching or martensing treatment on the material of the outer ring or inner ring that forms the cam surface of the one-way clutch, and the cam surface is pulled out. By forming by machining or rolling, it is possible to avoid sagging of both ends in the axial direction of the outer ring or inner ring caused by pressing, thereby increasing the load capacity of the one-way clutch and ensuring durability can do.

  In addition, because the outer ring or inner ring material that forms the cam surface of the one-way clutch is made of steel that has been burned or martensified, carburization or carburizing to give the product the necessary hardness. An expensive surface hardening heat treatment represented by nitriding, induction hardening, or the like is not necessary, and the cost can be reduced.

  Hereinafter, a pulley apparatus with a built-in one-way clutch according to the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view of an essential part for explaining a pulley device with a built-in roller clutch for an alternator which is an example of an embodiment of the present invention, and FIG. 2 is a view showing an inner ring having a concave cam surface.

  As shown in FIG. 1, a pulley apparatus 20 with a built-in roller clutch, which is an example of an embodiment of the present invention, is for driving an auxiliary machine such as an alternator, and a sleeve in which a rotation shaft (not shown) is fitted. 22. A pulley 23 is disposed around the sleeve 22 concentrically with the sleeve 22, and a radial load applied to the pulley 23 is supported between the outer peripheral surface of the sleeve 22 and the inner peripheral surface of the pulley 23, while the sleeve 22 is supported. A pair of support bearings 24 that enable relative rotation between the pulley 22 and the pulley 23 are disposed apart from each other in the axial direction, and the pulley 23 is disposed in a predetermined direction relative to the sleeve 22 between the pair of support bearings 24. A roller clutch (one-way clutch) 25 that transmits a rotational force from the pulley 23 to the sleeve 22 only when it tends to rotate is provided.

  The roller clutch 25 is arranged via a cage 21 between an inner ring 26 fitted on the sleeve 22, an outer ring 29 fitted on the pulley 23, and an outer peripheral surface of the inner ring 26 and an inner peripheral surface of the outer ring 29. A plurality of rollers 28 provided, and a spring (not shown) that presses the plurality of rollers 28 in a direction to engage with the outer peripheral surface of the inner ring 26 and the inner peripheral surface of the outer ring 29 are provided.

  The outer diameter of the roller 28 is larger than the distance between the outer peripheral surface of the inner ring 26 and the inner peripheral surface of the outer ring 29. The outer peripheral surface of the inner ring 26 has a concave shape called a ramp portion as shown in FIG. A plurality of cam surfaces 27 are formed at substantially equal intervals in the circumferential direction. On the cam surface 27, a roller 28 is supported by the cage 21 so as to be able to roll in a recess of the cam surface 27 and to be slightly displaceable in the circumferential direction.

  Only when the inner ring 26 (sleeve 22 side) and the outer ring 29 (pulley 23 side) tend to rotate relative to each other in a predetermined direction, the plurality of rollers 28, the outer peripheral surface of the inner ring 26 and the inner peripheral surface of the outer ring 29 are connected. Engage to transmit rotational force.

Here, in the present embodiment, a case-hardened steel obtained by subjecting the material of the inner ring 26 forming the cam surface 27 to a case quenching process is used, and the cam surface 27 is formed by drawing or rolling.
In this way, by forming the inner ring 26 with the cam surface 27 formed by drawing or rolling, the inner ring 26 can be manufactured with high accuracy and at low cost, and the axial direction of the inner ring 26 can be achieved by pressing. Since no sagging occurs on the peripheral surfaces of both end portions, the contact area between the cam surface 27 and the roller 28 is widened, the load capacity of the roller clutch 25 is increased, and sufficient durability can be ensured.

  Further, since the tempered steel is used as the material of the inner ring 26 on which the cam surface 27 is formed, a roller clutch manufactured by an expensive surface hardening heat treatment represented by carburizing, carbonitriding, induction hardening or the like as in the prior art. Compared with the built-in pulley device, the cost can be kept low.

  In addition, when it is necessary to provide the cam surface 27 with further durability, it is preferable to perform a marstressing process instead of the continuous quenching process. The marshalling process is a kind of carbonitriding process, and is a heat treatment for improving durability by mainly adding nitrogen to the surface of high carbon steel. Compared with general carburizing and carbonitriding processes, the process is performed at a low temperature and in a short time, so that an increase in cost can be minimized.

  As the inner ring material forming the cam surface, SUJ2, SK5, and SUS440C are selected in Examples 1 to 7 of the present invention, and the cam surface shape of the roller clutch inner ring shown in FIG. 2 is obtained by drawing or rolling the pipe material. processed. Thereafter, the pipe material was cut into a predetermined length, subjected to a continuous quenching process or a marstressing process, and the surface was adjusted by barrel processing to obtain a roller clutch inner ring. As a comparative example, the inner ring forming the cam surface is press-molded with SCM415, carburized or carbonitrided, barrel processed (Comparative Example 1 and Comparative Example 2), and drawn, and carburized. Alternatively, carbonitriding treatment and barrel processing (Comparative Example 3 and Comparative Example 4) were produced. Table 1 shows a list of specimens. In addition, the hardness of an Example and the hardness of a comparative example are adjusted to the equivalent level.

  The roller clutch inner ring obtained as described above was incorporated into the pulley apparatus shown in FIG. 1 and subjected to a durability test. The test conditions are as follows.

(Endurance test conditions)
Rotational speed: 12000 ± 300min ^-1
Test time: 40min x 3000cycle
Test temperature: 80 ° C

  All the examples and comparative examples cleared the test time. As a result of disassembling the pulley device after the test and observing the cam surface of the inner ring, the damages such as wear and deformation in Examples 1 to 7 were minor compared to Comparative Examples 1 and 2 (press-processed product). It was confirmed that the performance of the inner ring of the roller clutch according to the invention was superior to that of the comparative example. Moreover, the damage of the cam surface of the inner ring | wheel of Comparative Examples 3 and 4 which performed the drawing process is equivalent to Examples 1-7, and it can be said that the predominance of the drawing process with respect to press work has been confirmed.

  In the above-described embodiments, only SUJ2, SK5, and SUS440C have been described. However, other bearing steels, spring steels, tool steels, and the like, such as high-carbon sulphurized steels and marstressed steels may be used. Good. In the present embodiment and this example, the inner ring is selected as the member that forms the cam surface, but it goes without saying that the present invention can also be applied to a roller clutch having the cam surface formed on the outer ring.

It is principal part sectional drawing for demonstrating the roller clutch built-in type pulley apparatus for alternators which is an example of embodiment of the one-way clutch built-in type pulley apparatus which concerns on this invention. It is a figure which shows the inner ring | wheel which formed the concave cam surface, (a) is the figure seen from the axial direction, (b) is the sectional view on the AA line of (a). It is sectional drawing which shows an example of an alternator. It is principal part sectional drawing which shows the conventional roller clutch built-in type pulley apparatus for alternators.

Explanation of symbols

20 Pulley device with built-in roller clutch (pulley device with built-in one-way clutch)
22 Sleeve 23 Pulley 24 Support bearing 25 Roller clutch (one-way clutch)
26 Inner ring 27 Cam surface 29 Outer ring

Claims (2)

A sleeve in which a rotation shaft is fitted; a pulley disposed concentrically with the sleeve outside the sleeve; and an outer peripheral surface of the sleeve and an inner peripheral surface of the pulley, the pulley and the sleeve Only when they tend to rotate relative to each other in a predetermined direction, a one-way clutch having a concave cam surface that transmits rotational force between the pulley and the sleeve, an outer peripheral surface of the sleeve, and an inner periphery of the pulley A support bearing provided at a position spaced apart from the surface in the axial direction with respect to the one-way clutch and capable of rotating the pulley and the sleeve while supporting a radial load applied to the pulley. The one-way clutch built-in type pulley apparatus in which the cam surface of the one-way clutch is formed on the inner peripheral surface of the outer ring fitted in the pulley or the outer peripheral surface of the inner ring fitted on the sleeve. There,
A one-way clutch characterized by using steel obtained by subjecting the outer ring or inner ring material forming the cam surface to a quench hardening process or a marshalling process, and forming the cam surface by drawing or rolling. Built-in pulley device.   The one-way clutch built-in pulley apparatus according to claim 1, wherein the one-way clutch is a roller clutch.

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