JP2006029492A - One-way clutch and pulley device with built-in one-way clutch - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a one-way clutch less liable to engaging performance deterioration, heating and wear for actualizing smooth transition between an over-run condition and a locked condition while focusing attention on a reduction in drag resistance due to lubricant and on the adequate thickness of a lubricating film, and to provide a pulley device with the built-in one-way clutch. <P>SOLUTION: The one-way clutch comprises at least one of peripheral grooves 22, 22 formed in at least one of a transfer face 17a of a roller 17 and the cylindrical face of an inside member or an outside member. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a one-way clutch and a pulley device with a built-in one-way clutch. More specifically, the present invention is used as an auxiliary machine for an automobile, such as a starter, an alternator, a crank pulley, a compressor, or an auxiliary machine for engine idle stop. The present invention relates to a one-way clutch and a pulley device with a built-in one-way clutch.

  2. Description of the Related Art Conventionally, it is known to use a one-way clutch built-in pulley device as a pulley device for driving an auxiliary machine such as an alternator for generating electric power necessary for an automobile using an automobile driving engine as a driving source.

  For example, in a pulley device with a built-in one-way clutch incorporated in an alternator, a driven pulley over which a driving belt is stretched from a driving pulley fixed to a crankshaft, and a sleeve fixed to a rotating shaft of the alternator are provided. A one-way clutch and a pair of support bearings are disposed between the sleeve and the sleeve.

  When the rotational angular velocity of the driven pulley is higher than the rotational angular velocity of the rotating shaft of the alternator, the driven pulley and the sleeve become non-rotatable (locked) due to the wedge action of the roller of the one-way clutch, and the rotational force of the engine Is transmitted to the rotating shaft of the alternator. On the other hand, when the rotational angular velocity of the driven pulley is slower than the rotational angular velocity of the rotating shaft of the alternator, the driven pulley and the sleeve can rotate freely (overrun state). Therefore, even when the rotational angular velocity of the crankshaft fluctuates, the endless belt and the pulley are prevented from rubbing by the action of the one-way clutch, and the endless belt is prevented from being shortened due to the generation of abnormal noise called abrasion and wear. It is possible to prevent the power generation efficiency of the alternator from decreasing.

  Under the high-speed rotation conditions that have been demanded in recent years, an excessively variable load is applied to the roller of the one-way clutch and the pair of support bearings from the drive belt via the pulley. For this reason, in the one-way clutch, smooth switching between the overrun state and the locked state is required in terms of rigidity for supporting the pulley load, operability, and the like.

As a measure for improving the switching performance between the overrun state and the locked state of the one-way clutch, a method corresponding to the inner ring and the portion corresponding to the outer ring is integrated from the viewpoint of preventing eccentricity (for example, see Patent Documents 1 and 2) And a method of reducing the amount of eccentricity between the rotor side and the pulley side by a leaf spring (see, for example, Patent Document 3).
JP-A-8-166027 JP 2003-113925 A JP 2002-70990 A

  By the way, in order to improve the support rigidity of the one-way clutch with respect to the pulley load, it is devised to use a lubricating oil having a high viscosity. In this case, although the rigidity is increased, an oil film more than necessary is formed between the roller and the raceway, and the resistance to the starting of the roller is increased, so that the roller is not easily engaged during switching. This tendency is also true when the viscosity of the lubricating oil is increased in a low temperature environment.

  Further, when the lubricant is excessively present, the roller slips more easily on both the radial load load side and the counter load side, and drag resistance due to the excessive lubricant is generated. In particular, for a while after the start of use, the grease is excessively present without being adapted, and this tendency is strong, and there is a possibility that the biting property is reduced, heat generation, and wear are likely to occur. That is, as shown in FIG. 6, when the radial surface of the roller 103 is a smooth surface, a large contact resistance corresponding to the axial length occurs between the roller 103 and the raceway rings 101 and 102. The lubricant L blocked by the smooth radial surface of the roller 103 causes drag resistance. In particular, when the lubricant is excessive, such as at the start of use, the drag resistance is increased and a failure is likely to occur.

  The present invention has been made in view of the above-mentioned problems, and its purpose is to reduce drag resistance due to a lubricant and an appropriate lubricating film thickness, to reduce biting property, heat generation, and wear, It is an object to provide a one-way clutch and a pulley device with a built-in one-way clutch that can smoothly transition between an overrun state and a locked state.

The above object of the present invention can be achieved by the following constitution.
(1) Provided between the inner member, a cylindrical outer member disposed concentrically with the inner member around the inner member, and the outer peripheral surface of the inner member and the inner peripheral surface of the outer member. A plurality of rollers, and only when one of the inner member and the outer member tends to rotate relative to the other in a predetermined direction, the roller is interposed between the inner member and the outer member. A one-way clutch that allows free transmission of rotational force,
Of the outer peripheral surface of the inner member and the inner peripheral surface of the outer member, one constitutes a cylindrical surface and the other constitutes a cam surface,
The one-way clutch, wherein at least one circumferential groove is formed in at least one of a rolling surface of the roller and the cylindrical surface.
(2) The one-way clutch according to (1), wherein the circumferential groove is provided symmetrically with respect to an axial center of the roller or the cylindrical surface.
(3) The one-way clutch according to (1) or (2), wherein a curved portion is formed at an end of the circumferential groove.
(4) The one-way clutch according to (1) or (2), wherein a surface hardening treatment is performed at least in the vicinity of the end of the circumferential groove.
(5) A one-way clutch built-in type pulley apparatus comprising the one-way clutch according to any one of (1) to (4).
The circumferential groove is symmetrical with respect to the axial center of the roller means that the circumferential groove is provided on the roller, and the circumferential groove is symmetrical with respect to the axial center of the cylindrical surface. It means the case where it is provided on the cylindrical surface.

  According to the one-way clutch and the pulley device with a built-in one-way clutch of the present invention, at least one circumferential groove is formed on at least one of the rolling surface of the roller and the cylindrical surface formed on the outer member or the inner member. Therefore, when the lubricant passes through the roller through the circumferential groove, the drag resistance due to the lubricant is reduced and the lubricant has an appropriate lubricating film thickness. And a smooth transition between the locked state is possible.

  Hereinafter, a one-way clutch and a pulley device with a built-in one-way clutch according to each embodiment of the present invention will be described in detail with reference to the drawings.

(First embodiment)
FIG. 1 is a longitudinal sectional view of a pulley device with a built-in one-way clutch according to a first embodiment of the present invention, and FIG. 2 is a sectional view schematically showing the one-way clutch in FIG.

  As shown in FIG. 1, a pulley device 10 with a built-in one-way clutch includes a sleeve 11 that can be fixed by being screwed to a rotation shaft (not shown) of an auxiliary machine such as an alternator, and a sleeve radially outside the sleeve 11. 11, and a pulley 12 having a belt groove 12a formed on the outer peripheral surface thereof. A drive belt (not shown) suspended from a drive pulley (not shown) fixed to the crankshaft of the engine is stretched over the belt groove 12a.

  A one-way clutch 13 is disposed between the outer peripheral surface of the sleeve 11 in the axial intermediate portion and the inner peripheral surface of the pulley 12 in the axial intermediate portion. A pair of support bearings 14 are arranged between the pulley 12 and the inner peripheral surface at both axial ends of the pulley 12 so as to sandwich the one-way clutch 13. A deep groove ball bearing is used as the support bearing 14 and supports the sleeve 11 and the pulley 12 so as to be relatively rotatable while supporting a radial load applied to the pulley 12.

  As shown in FIGS. 1 and 2, the one-way clutch 13 is press-fitted and fixed to the outer peripheral surface of the sleeve 11, and is press-fitted and fixed to the inner ring 15 that is an inner member that rotates together with the rotating shaft, and the inner peripheral surface of the pulley 12. The outer ring 16 is a cylindrical outer member disposed concentrically with the inner ring 15 around the inner ring 15, and is rotatably provided between the outer peripheral surface of the inner ring 15 and the inner peripheral surface of the outer ring 16. And a plurality of rollers 17. The one-way clutch 13 includes a cage 18 having a plurality of pockets for individually accommodating the rollers 17 and a spring that is an elastic body that is fixed to the cage 18 and elastically presses the rollers 17 in the locking direction. 19.

  The outer peripheral surface of the inner ring 15 forms a cam surface having a plurality of recesses 20 formed at equal intervals in the circumferential direction, and the roller 17 is a wedge space formed by the cylindrical surface 21 of the outer ring 16 and each recess 20. Is held rotatably.

  The pulley apparatus 10 with a built-in one-way clutch configured in this way has a tendency that the outer ring 16 rotates relative to the inner ring 15 in a predetermined direction when the rotational angular speed of the pulley 12 is faster than the rotational angular speed of the rotating shaft. In this case, based on the force received from the outer peripheral surface of the outer ring 16 and the spring force of the spring 19, the roller 17 bites in a wedge shape on the side where the recess 20 is shallow, that is, on the side where the width of the wedge space is narrow. Each roller 17 is engaged between 16 and the inner ring 15. As a result, the pulley 12 and the sleeve 11 cannot be rotated relative to each other (in a locked state), and the rotational force of the engine is transmitted to the rotating shaft. On the other hand, when the rotational angular velocity of the pulley 12 is slower than the rotational angular velocity of the rotating shaft, the roller 17 is on the side where the recess 20 is deepened against the spring force of the spring 19 based on the force received from the outer peripheral surface of the outer ring 16. That is, the wedge space is displaced to the wider side, the engagement of the roller 17 is released, and the pulley 12 and the sleeve 11 can be rotated relative to each other (overrun state).

  Here, in the one-way clutch 13 of this embodiment, as shown in FIG. 3, a pair of annular circumferential grooves 22, 22 are formed on the radial surface 17 a constituting the rolling surface of the roller 17. The pair of circumferential grooves 22 and 22 are provided symmetrically with respect to the axial center of the roller 17 with respect to the shape and specifications. The specifications of the circumferential grooves 22 and 22 were adjusted in terms of the amount of the lubricant L passing through the circumferential groove 22 and the thickness of the lubricating film to prevent friction and seizure and improve the roller biting property. The optimum design.

  In particular, regarding the size of the circumferential grooves 22, 22, the total axial width of the circumferential grooves 22, 22 is the axial length of the roller 17 in consideration of maintaining the load capacity of the roller 17 and preventing the occurrence of high surface pressure. It is desirable that it is 30% or less. That is, in the roller 17 having the axial length b having n circumferential grooves 22 and 22 (two circumferential grooves in FIG. 3) having the same axial width a, a · n / b ≦ 0.30. It is desirable.

  Moreover, since the said surrounding grooves 22 and 22 are formed by carrying out the groove process of the radial surface 17a, there is a concern that the contact wear in the edge parts 22a and 22a of the surrounding grooves 22 and 22 may generate | occur | produce. In order to avoid such contact wear, the end portions 22a and 22a of the circumferential grooves 22 and 22 are formed with curved portions by defacement processing.

  Further, in the vicinity of the end portions of the circumferential grooves 22 and 22, a surface hardening process with a small friction coefficient is performed. Examples of surface hardening treatment include ceramic coating alloys such as Ti alloys and coatings such as diamond-like carbon (DLC). Furthermore, by performing a surface hardening treatment on the vicinity of the end portions of the circumferential grooves 22 and 22 or on the entire radial surface, it is effective in preventing contact wear at the end portions of the circumferential grooves and the entire radial surface.

  Therefore, in this embodiment, since the circumferential groove 22 is formed in the radial surface 17a of the roller 17, since the lubricant L passes through the roller 17 through the circumferential groove 22, the drag resistance by the lubricant L is reduced. The lubrication film thickness between the roller 17 and the concave portion 20 or the cylindrical surface 21 which is the raceway surface becomes an appropriate value, and the overrun state and the lock are compared with the case of the smooth radial surface shown in FIG. The bite of the roller 17 in the transition between states is improved. As a result, smoother biting by a larger number of rollers 17 than before can be achieved, leading to improved operability and reduced wear and heat generation. Here, by optimizing the specifications of the circumferential groove 22, it is possible to adjust the amount and form of the lubricant L through the circumferential groove 22 and the thickness of the lubricating film between the roller 17 and the raceway. Therefore, it is possible to design from both aspects of preventing wear and seizure and improving the biting property of the roller.

  Although the number of the circumferential grooves 22 in this embodiment is two, the number of the circumferential grooves is arbitrary, and at least one circumferential groove may be formed. However, the number and shape of the circumferential grooves affect the degree of drag resistance reduction, the processing cost, the generated pressure between the rolling surface of the roller 17 and the raceway surface, and so on. It is desirable to consider the optimum specifications. In particular, with respect to the size of the circumferential groove, the load capacity of the roller 17 is maintained and the high surface pressure is maintained by setting the sum of the axial widths of the circumferential grooves 22 and 22 to 30% or less of the axial length of the roller 17. Can be prevented.

  Further, since the circumferential groove 22 of the present embodiment is symmetrical in shape and specifications with respect to the center of the roller 17 in the axial direction, the flow and stress of the lubricant L generated due to the groove is directed in the traveling direction of the roller 17. Thus, the roller 17 is inclined due to the left and right circumferential grooves 22 being different from each other, and the occurrence of local surface pressure and wear due to the inclination is prevented. However, the above effects can be achieved by intentionally making the left and right asymmetrical when the load applied to the roller 17 and the lubrication condition are not symmetrical or when the lubricant L is likely to leak in any direction of the shaft end.

  In addition, since the curved portion is provided by performing the end portion 22a of the circumferential groove 22, when the roller 17 is inclined or an impact load is applied, damage can be minimized. A practical one-way clutch can be provided. Furthermore, the surface wear treatment is performed on the vicinity of the end portion of the circumferential groove 22 and on the entire radial surface 17a, whereby contact wear at the end portion 22a of the circumferential groove 22 and the radial surface 17a can be further reduced.

(Second Embodiment)
Next, a one-way clutch and a pulley device with a built-in one-way clutch according to a second embodiment of the present invention will be described in detail with reference to FIGS. In this embodiment, the configuration other than the shape of the roller and outer ring of the one-way clutch is the same as that of the first embodiment. For this reason, the same parts as those of the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted or simplified.

  In the one-way clutch 30 of the present embodiment, instead of providing a circumferential groove on the radial surface 31 a of the roller 31, a pair of annular circumferential grooves 33, 33 are formed on the cylindrical surface 32 a that is the inner circumferential surface of the outer ring 32. . The pair of circumferential grooves 33 and 33 are provided symmetrically with respect to the axial center of the roller 31 with respect to the shape and specifications, that is, symmetrical with respect to the axial center of the inner peripheral surface of the outer ring 32. The specifications of the circumferential grooves 33 and 33 were adjusted from the viewpoints of preventing friction and seizure and improving the biting property of the roller by adjusting the amount of the lubricant L passing through the circumferential groove 33 and the lubricating film thickness. The optimum design.

  Therefore, in the one-way clutch and the pulley device with a built-in one-way clutch of the present embodiment, the circumferential groove 33 is formed on the cylindrical surface 32a of the outer ring 32, so that the lubricant L passes through the circumferential groove 33 and the roller 31 and the outer ring. Pass between 32. For this reason, even when the viscosity of the lubricant is high, the amount of the lubricant is large, or even when the relative speed between the cylindrical surface 32a and the roller 31 is high, the conventional configuration shown in FIG. In comparison, the oil film between the roller 31 and the outer ring 32 does not become thick, and the biting failure due to the influence of the oil film can be reduced.

  In addition, in the conventional configuration shown in FIG. 6, countermeasures against the above-mentioned biting failure can be considered by using a lubricant having a low viscosity or reducing the amount of the lubricant. Causes seizure of time. On the other hand, in this embodiment, it is not necessary to use a lubricant having a low viscosity, or to reduce the amount of the lubricant, and the seizure resistance is not lowered.

  Further, in the one-way clutch 30, the material of the roller 31 is harder than the material of the outer ring 32, so that it is easier to process the peripheral ring 33 provided in the outer ring 32.

  Although the number of the circumferential grooves 33 in this embodiment is two, the number of the circumferential grooves is arbitrary as in the first embodiment, and at least one circumferential groove may be formed. However, the number and shape of the circumferential grooves affect the degree of drag resistance reduction, processing cost, generated pressure between the rolling surface of the roller 31 and the raceway surface, etc. It is desirable to consider the optimum specifications.

  Further, the circumferential groove 33 of the present embodiment has a shape and specifications that are symmetrical with respect to the axial center of the roller 31, that is, the axial center of the cylindrical surface 32a of the outer ring 32 that the roller 31 faces. The flow and stress of the lubricant L generated in this way become symmetrical in the direction of travel of the roller 31, and the inclination of the roller 31 due to the difference in the circumferential groove 33 between the left and right, or the occurrence of local surface pressure and wear due to the inclination Is prevented. Here, the effect of the symmetrical circumferential grooves will be described below. For example, when two circumferential grooves are provided on the roller or raceway cylindrical surface, if the left and right groove widths are different (in the example shown in FIG. 7, the left groove width <the right groove width), the lubricant L Since the drag resistance force is different between the left side and the right side of the roller, the roller is inclined, and there is a risk that local surface pressure and wear occur due to this inclination. In addition to the groove width shown in FIG. 7, the circumferential groove shape such as the groove depth and the groove cross-sectional shape is provided. When the circumferential groove is provided on the roller, the circumferential groove is provided on the raceway cylindrical surface with respect to the axial center of the roller. This can be reduced by making it symmetrical about the axial center of the raceway cylindrical surface.

  Next, the difference between the case where the circumferential groove is provided on the raceway cylindrical surface and the case where the peripheral groove is provided on the roller surface will be described from the viewpoint of manufacturing in the case where the axial movement of the roller occurs. In the case where a circumferentially symmetric circumferential groove is provided on the raceway cylindrical surface, if the roller greatly moves in the axial direction during operation, the axial distribution of the force received by the roller becomes asymmetrical, which causes the roller to tilt. On the other hand, in the case where the roller is provided with a symmetrical circumferential groove, the axial distribution of the force applied to the roller is symmetrical even if the roller moves greatly in the axial direction, thereby preventing the roller from tilting. The effect is retained. For this reason, when the roller moves largely in the axial direction, it is desirable to provide a circumferential groove on the roller surface rather than the raceway cylindrical surface from the viewpoint of the inclination (skew) of the roller.

  On the other hand, from the viewpoint of manufacturing, it is more cost-effective to manufacture a groove on one raceway cylindrical surface than to groove all rollers, and inspection of the groove processing accuracy can be performed on one raceway cylindrical surface. The advantage is that only it is necessary. For this reason, in selecting the surface on which the circumferential groove is provided, it is desirable to make a decision after considering both the influence of the inclination of the roller and the manufacturing cost.

  The effect of making the circumferential groove symmetric is described above. However, when the load applied to the roller 31 and the lubrication condition are not symmetric, or when the lubricant L easily leaks in any direction of the shaft end, it is intentionally left-right asymmetric. Thus, the above effects can be achieved.

  In addition, about another structure and effect | action, it is the same as that of 1st Embodiment, The magnitude | size of the groove width of the circumferential grooves 33 and 33, and the curved part by the depressing process of the edge parts 33a and 33a of the circumferential grooves 33 and 33 The surface hardening treatment in the vicinity of the end portions of the circumferential grooves 33 and 33 can also be configured in the same manner as in the first embodiment.

In addition, this invention is not limited to embodiment mentioned above, A deformation | transformation, improvement, etc. are possible suitably.
In the present invention, the support bearings disposed on both axial sides of the one-way clutch may be rolling bearings of a type other than the deep groove ball bearing.

  Further, the inner ring of the one-way clutch that is the inner member and the inner ring of the support bearing may be configured separately from the sleeve as in this embodiment, or may be integrally formed on the sleeve and the rotating shaft. Similarly, the outer ring of the one-way clutch that is the outer member and the outer ring of the support bearing may be configured separately from the pulley as in this embodiment, or may be integrally formed on the pulley.

In this embodiment, the pulley device with a built-in one-way clutch is mounted between the rotating shaft of the alternator and the driven pulley, but is a pulley device with a built-in one-way clutch for starter mounted between the pulley of the starter and the rotating shaft. In this case, only when the outer ring of the inner ring has a cylindrical surface and a cam surface is formed on the inner ring of the outer ring, the inner ring tends to rotate relative to the outer ring in a predetermined direction. Rotational force can be transmitted to and from the outer ring. In this case, the circumferential groove may be formed on at least one of the rolling surface of the roller and the cylindrical surface formed on the outer circumferential surface of the inner ring.
In addition, when the pulley device with a built-in one-way clutch is used for driving an auxiliary machine of an engine idle stop mechanism, an auxiliary machine such as a compressor is driven by a dedicated motor when the engine is stopped. Although it does not receive, it becomes the structure which receives the rotation fluctuation generate | occur | produced from the motor for an auxiliary machine drive.

It is a longitudinal cross-sectional view of the one-way clutch built-in type pulley apparatus in 1st Embodiment. It is sectional drawing which shows typically the one way clutch in FIG. In the one-way clutch of 1st Embodiment, it is a schematic diagram which shows the flow of the lubricant at the time of a roller rolling. It is sectional drawing which shows typically the one way clutch of 2nd Embodiment. In the one-way clutch of 2nd Embodiment, it is a schematic diagram which shows the flow of the lubricant at the time of a roller rolling. It is a schematic diagram which shows the flow of the lubricant when a roller rolls in the conventional one-way clutch. It is a schematic diagram which shows the flow of the lubricant at the time of a roller rolling when the groove width of a circumferential groove differs.

Explanation of symbols

10 One-way clutch built-in pulley device 11 Sleeve
12 Pulley 12a Belt groove 13, 30 One-way clutch 14 Support bearing 15 Inner ring 16, 32 Outer ring 17, 31 Roller 18 Cage 19 Spring (elastic body)
20 concave portion 22, 33 circumferential groove

Claims (5)

An inner member; a cylindrical outer member disposed concentrically with the inner member around the inner member; and a plurality of rollers provided between an outer peripheral surface of the inner member and an inner peripheral surface of the outer member And the rotational force between the inner member and the outer member via the roller only when one of the inner member and the outer member tends to rotate relative to the other in a predetermined direction. A one-way clutch that allows the transmission of
Of the outer peripheral surface of the inner member and the inner peripheral surface of the outer member, one constitutes a cylindrical surface and the other constitutes a cam surface,
The one-way clutch, wherein at least one circumferential groove is formed in at least one of a rolling surface of the roller and the cylindrical surface.   The one-way clutch according to claim 1, wherein the circumferential groove is provided symmetrically with respect to an axial center of the roller or the cylindrical surface.   The one-way clutch according to claim 1 or 2, wherein a curved portion is formed at an end of the circumferential groove.   The one-way clutch according to claim 1 or 2, wherein a surface hardening treatment is performed at least in the vicinity of the end of the circumferential groove.   A one-way clutch built-in type pulley apparatus comprising the one-way clutch according to claim 1.

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