JPH1163172A - Pulley with built-in clutch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pulley with a built-in clutch having features of small eccentricity of a bearing portion and good durability, and a manufacturing method therefor. SOLUTION: An inner member 23 is made of a steel product including residual austenite, and the inner member 23 and a pulley 24 are fabricated such that a radial clearance of a bearing portion formed of two track grooves 28, 29 and a steel ball 26 has a small positive vale. This assembly is then tempered at a higher temperature than the transformation temperature of martensite of the inner member consisting of the steel product, and the swelling resulting from the transformation of the residual austenite brings the radial clearance of the bearing portion to a negative value. This result in a small amount of eccentricity of the bearing portion generated by a radial load, a small amount of an angular change of a sprag 27 during one rotation of the pulley 24, a reduction of abrasion or the like of the sprag 27, and better durability of the pulley with a built-in clutch.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pulley having a built-in clutch and a method of manufacturing the same.

[0002]

2. Description of the Related Art A pulley used for transmitting the rotation of a crankshaft for an automobile to an alternator is provided with a clutch in order to rotate the rotating shaft of the alternator having a large inertial force at a constant speed as much as possible. Built-in ones are used. That is, the pulley with a built-in clutch transmits rotation when the rotation of the crankshaft is faster than the rotation of the AC generator, and when the rotation of the crankshaft becomes slower than the rotation of the AC generator, the pulley with a one-way clutch is engaged. By canceling the combination, the rotating shaft of the alternator is freely rotated.

A pulley with a built-in clutch used for driving an alternator for a car of this type is disclosed in Japanese Patent Application No. Hei 8-2 filed by the present applicant for the purpose of compact design.
No. 56630 describes a pulley with a built-in clutch.

The pulley with a built-in clutch will be described with reference to FIGS. 3 to 6 showing one embodiment of the present invention. This pulley with a built-in clutch, as shown in FIGS. 3 and 4,
An inner member 1 attached to a shaft, a cylindrical outer member 2 disposed outside the inner member 1, and a plurality of steel balls held and incorporated between the two members 1 and 2 by a retainer 3; 4 and a sprag 5 and a pulley 6 fitted on the outer diameter surface of the outer member 2.

[0005] The outer diameter surface of the inner member 1 and the inner diameter surface of the outer member 2 have track grooves 7 and 8 extending in the circumferential direction of an arc-shaped cross section, and cylindrical surfaces 9 on both sides of each of the track grooves 7 and 8. ,
10 are provided. The plurality of steel balls 4 are fitted into the two raceway grooves 7 and 8 to form a bearing. The plurality of sprags 5 are arranged so as to straddle both the raceway grooves 7 and 8.

As shown in FIG. 5, the retainer 3 comprises a retainer body 3a made of a polyimide resin and a lid 3b made of a polyimide resin, and a plurality of pins 11 are provided at one axial end of the retainer body 3a. These pins 11 are fitted into pin holes 12 provided in the lid 3b to be integrated. Also, a plurality of pins 13 are formed on the other end side in the axial direction of the retainer body 3a, and a spring ring 14 described later is attached to each of the pins 13.

In the retainer main body 3a, spaces 15 for accommodating the steel balls 4 and spaces 16 for accommodating the sprags 5 are provided alternately. As shown in FIG. 6, the steel balls 4 and the sprags 5 are provided. The retainers 3 are alternately arranged in the circumferential direction. Grease 17 is also sealed in the space 15 for accommodating the steel balls 4.

The sprag 5 has a length extending over both the raceway grooves 7 and 8, and has cylindrical surfaces 9 of the inner member 1 and the outer member 2 on inner and outer ends of its outer peripheral surface. An arcuate cylindrical surface 18, 19 that engages with 10 is formed.

The sprag 5 is attached to the spring ring 14.
The same number of spring pieces 20 are formed by cutting and raising, and each spring piece 20 is inserted into a space 16 for accommodating the sprag 5 from a window provided in the retainer main body 3a and presses the sprag 5, and by this pressing, The arcuate cylindrical surfaces 18, 19 of the sprag 5 are in contact with the cylindrical surfaces 9, 10 of the inner member 1 and the outer member 2, respectively.

The lid 3b is provided with every other stopper 21 corresponding to the circumferential position of the space 15 for accommodating the steel balls 4, and each stopper 21 is attached to each steel ball 4 by one.
The cage 3 is in contact with every other to prevent the cage 3 from moving in the axial direction. Further, on both sides of the retainer 3, seal members 22 of a bearing portion are attached.

The pulley 6 is tightly fitted to the outer diameter surface of the outer member 2, and receives a driving force by a belt (not shown), and rotates in the direction of the arrow in FIG.

When the pulley 6 rotates in the direction of the arrow in FIG. 4, the outer member 2 also integrally rotates in the same direction, so that the sprag 5 has its arcuate cylindrical surface 19 and the cylindrical surface of the outer member 2. Due to the contact with the cylinder 10, a clockwise rotational moment is received, and the arcuate cylindrical surfaces 18 and 19 engage with the cylindrical surfaces 9 and 10 of the inner member 1 and the outer member 2. Therefore, the shaft rotates together with the inner member 1, and the driving force is transmitted.

When the rotation speed of the shaft is higher than the rotation speed of the pulley 6, the pulley 6
, The sprags 5 receive a counterclockwise rotational moment, and are disengaged from the cylindrical surfaces 9 and 10. So, in this case,
The shaft and the inner member 1 rotate freely without being restricted by the rotation of the pulley 6.

[0014]

In the pulley with a built-in clutch of the type described above, when assembling the inner member and the outer member, the radial gap between the bearing portions formed by the two raceway grooves and the rolling elements is corrected in terms of assembly work. The outer member is reduced in diameter by tightly fitting the pulley after that, and the radial gap of the final product is designed to have a small positive value of about 10 μm.

In the pulley with a built-in clutch, a radial load is applied to the bearing portion by a tension of a belt for transmitting a driving force. Due to the radial load, the inner member and the outer member are eccentric to each other by an amount corresponding to the radial gap and an amount of displacement due to elastic deformation of the bearing portion.

Regarding the case where there is no eccentricity and the case where there is,
The change in the rotation angle of the sprag 5 will be described. FIG. 7 is a schematic diagram when there is no eccentricity, and FIG. 8 is a schematic diagram when there is eccentricity. In both figures, four sprags 5 are typically arranged at 90 ° phase between the cylindrical surface 9 of the inner member and the cylindrical surface 10 of the outer member.

In the case where there is no eccentricity in FIG. 7, the point where each sprag 5 contacts the cylindrical surface 9 is P, the point where each sprag 5 contacts the cylindrical surface 10 is Q, a straight line PQ connecting these points, and the center of the inner member. An angle between a straight line OP connecting O and the point P is defined as θ. In this case, the angle θ, that is, the inclination of the sprags 5 when the sprags 5 are engaged with the cylindrical surfaces 9 and 10 is the same for both sprags 5.

In the case where the eccentricity is shown in FIG. 8, the amount of eccentricity between the center O of the inner member and the center O 'of the outer member is represented by e. The four sprags 5 are sequentially moved counterclockwise by 5
a, 5b, 5c, 5d, and each sprag 5a, 5b, 5d.
The points at which c and 5d are in contact with the respective cylindrical surfaces 9 and 10 are represented by P 'and Q'.
And These points P 'and Q' move from the positions of the contact points P and Q of each sprag 5 when there is no eccentricity, and the amount of movement is such that the distance between the two cylindrical surfaces 9 and 10 is maximum and minimum. The sprags 5a and 5c arranged at the respective positions are very large, and the inclinations of the sprags are opposite to each other.

As described above, in this clutch built-in pulley, the inner member and the outer member rotate together with the rotation of the pulley with the sprag 5 engaged with the cylindrical surfaces 9, 10. Accordingly, the inclination of each sprag 5 is determined by the tension of the belt with the eccentricity shown in FIG.
Is repeated.

When the contact points P 'and Q' in FIG. 8 are moved, the angle formed by a straight line PQ connecting the original contact points P and Q and a straight line OP 'connecting the contact point P' and the center point O is shown. β. If the angles of the sprags 5a and 5c are βa and βc, respectively, the angle change Δβ of the inclination of the sprag 5 in one rotation of the pulley is βa−βc.
As can be seen from FIG. 8, the signs βa and βc have opposite signs, so the angle change amount Δβ has a very large value. The large angular change of the sprags 5 during rotation of the pulley has a problem in that the sprags 5 and the cylindrical surfaces 9 and 10 in contact with the sprags 5 are worn out. There is also a problem that deterioration of the grease is accelerated by the wear.

In addition, when the sprags 5 are engaged with the two cylindrical surfaces 9 and 10, the movement of the sprags 5 does not become smooth due to the restraint by the contact surface pressure. The radial load and the driving torque due to the
There is also a problem that excessive force is applied to the device.

As described above, a large eccentricity of the pulley bearing portion with a built-in clutch leads to deterioration of the bearing portion and lowers the durability of the product.

An object of the present invention is to provide a pulley with a built-in clutch which can reduce the eccentricity of the bearing portion and has excellent durability, and a method of manufacturing the same.

[0024]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention is directed to a steel having a raceway groove extending in the circumferential direction and an outer diameter surface having a cylindrical surface on both sides thereof, and which is mounted on a shaft. Inner member, a steel pulley having a raceway groove arranged outside of the inner member and having a circumferentially continuous raceway and an inner diameter surface provided with cylindrical surfaces on both sides thereof, and both raceway grooves of the inner member and the pulley A plurality of rolling elements fitted and held in the inner member and the plurality of rolling elements astride the two raceway grooves and held between the inner surfaces of the inner member and the cylindrical surface of the pulley so as to be disengageable from these cylindrical surfaces. In the pulley with a built-in clutch comprising a sprag, the inner member, the material of which contains residual austenite, and after assembling with the pulley, the residual austenite expands due to martensitic transformation. Formed of wood, said it had adopted a structure that a negative value of the radial clearance of the bearing portion formed by both raceway grooves and the rolling element.

Further, the present invention provides a steel inner member having a raceway groove extending in the circumferential direction and an outer diameter surface having cylindrical surfaces on both sides thereof, the steel inner member being attached to a shaft, and a steel inner member disposed outside the inner member. A cylindrical steel outer member having a raceway groove extending in the circumferential direction and an inner diameter surface provided with cylindrical surfaces on both sides thereof, and was fitted and held in both raceway grooves of the inner member and the outer member. A plurality of rolling elements, a plurality of sprags which are held between the cylindrical surfaces of the inner member and the outer member across the two raceway grooves, and are disposed so as to be disengageable from the cylindrical surfaces; and In the pulley with a built-in clutch formed of a pulley fitted to the outer diameter surface of the inner member, the material of the inner member includes residual austenite, and after assembling with the outer member, the residual austenite is removed. The pulley is formed of a steel material that has been transformed and expanded in the form of rutensite. A configuration can also be employed.

In manufacturing each of the above-mentioned pulleys with a built-in clutch, a steel material containing residual austenite is used as a material of the inner member, and the radial gap between the bearing groove formed by the both raceway grooves and the rolling element is a small positive value As a result, the inner member and the pulley or the outer member provided with the raceway groove are assembled, and thereafter, the assembly is tempered at a temperature higher than the martensitic transformation temperature of the steel material of the inner member, The method of setting the radial gap to a negative value was adopted.

That is, a steel material containing retained austenite is used as a material of the inner member, and the inner race member is assembled in advance so that the radial gap between the bearing portions formed by the two raceway grooves and the rolling elements has a small positive value. By tempering this assembly at a temperature higher than the martensitic transformation temperature of the steel material of the inner member, and making the radial gap of the bearing portion a negative value by utilizing the transformation expansion of the retained austenite, the belt It is possible to prevent eccentricity due to backlash of the bearing portion caused by a radial load applied by tension. In addition, by applying a slight prestress to the bearing portion at the negative radial gap, eccentricity due to elastic deformation of the bearing portion can be reduced.

The negative radial gap is -10 μm.
The rolling element is not locked in the raceway groove at such a small negative radial clearance.

When the pulley is a pulley with a built-in clutch separate from the outer member, the separate pulley is tightly fitted on the outer diameter surface of the assembly to reduce the diameter of the outer portion. The radial clearance can be made a negative value by combining the effects of expansion.

[0030]

Embodiments of the present invention will be described below. 1 and 2 show a first embodiment. The clutch built-in pulley includes a steel inner member 23,
It is basically composed of a steel pulley 24, a plurality of steel balls 26 and sprags 27 held and incorporated by a retainer 25 between these two members 23, 24, and an outer diameter surface of the inner member 23. On the inner diameter surface of the pulley 24, there are provided raceway grooves 28, 29 which extend in the circumferential direction of the arc-shaped cross section, and cylindrical surfaces 30, 31 are provided on both sides of each of the raceway grooves 28, 29. The plurality of steel balls 26 are provided in the two raceway grooves 28, 29.
To form a bearing portion, the plurality of sprags 2
7 is disposed so as to straddle both track grooves 28 and 29.

In the pulley with a built-in clutch, a bearing steel having a retained austenite amount of 6% is used as a material of the inner member 23, and the inner member 23 and the pulley 2 are used.
No. 4 is manufactured by assembling such that the radial gap between the bearing portions formed by the two raceway grooves 28 and 29 and the steel ball 26 is 10 μm, and tempering this assembly at 300 ° C.

The outer diameter of the inner member 23 is 50 mm,
Since the coefficient of linear expansion due to transformation from retained austenite to martensite is about 7 × 10 ⁻³ , the amount of outer diameter expansion of the inner member 23 containing 6% of retained austenite by the tempering treatment can be calculated by the following equation. 50 mm × (7 × 10 ⁻³ ) × 0.06 = 2 × 10 ⁻² mm
= 20 μm Therefore, the radial gap of the final product is −10 μm
It is.

FIGS. 3 and 4 show a second embodiment.
In this pulley with a built-in clutch, the pulley 6 and the outer member 2 are formed separately, and the pulley 6 is tightly fitted on the outer diameter surface of the outer member 2. The material of the inner member 1 is bearing steel having the same amount of retained austenite of 6% as in the first embodiment, and has the same size.

As in the first embodiment, the outer circumferential surface of the inner member 1 and the inner circumferential surface of the outer member 2 have track grooves 7, 8 connected in the circumferential direction of an arc-shaped cross section, and each of these track grooves. Cylindrical surfaces 9, 10 are provided on both sides of 7, 8, and a plurality of steel balls 4 are fitted in the two raceway grooves 7, 8 to form a bearing portion, and a plurality of sprags 5 are formed on the two raceway grooves 7, 8. 8 are arranged.

In this pulley with a built-in clutch, the inner member 1 and the outer member 2 are assembled so that the radial gap between the bearing portions formed by the two raceway grooves 7, 8 and the steel ball 4 is 40 μm. Was subjected to a tempering treatment at 300 ° C., and the pulley 6 was fitted to this with a interference of 40 μm.

In this case, the outer diameter expansion amount of the inner member 1 due to the tempering treatment is 20 μm, which is the same as that of the first embodiment.
m, the amount of reduction in the inner diameter of the outer member 2 due to the fitting of the pulley is 30 μm, and the radial clearance of the final product is −10 μm.

The valley diameter of each of the clutch built-in pulleys is 60 mm.

Examples and comparative examples will be described below.

[0039]

EXAMPLE A pulley with a built-in clutch having a radial clearance of -10 .mu.m manufactured by the method shown in the first embodiment was prepared.

[0040]

COMPARATIVE EXAMPLE The pulley with a built-in clutch having the same reference dimensions as that of the embodiment, the radial clearance in a state where the inner member and the outer member are assembled is 40 μm, and the pulley is
With a fitting of 0 μm, the final radial gap is 10
A pulley with a built-in clutch manufactured to have a thickness of μm was prepared.

With respect to the pulleys with a built-in clutch of the embodiment and the comparative example, when these were attached to the rotating shaft and driven by a belt, the angle change Δβ of the sprags during one rotation of the pulley was calculated. The belt tension was 80 kgf in each case.

In the calculation, the amount of eccentricity of the bearing portion due to the belt tension is defined as the sum of the amount of elastic displacement of the bearing portion obtained from the elastic deformation analysis and 1/2 of the radial gap. Was obtained.

As a result, the angle change amount Δβ of the embodiment is 5.
4 ° and Δβ of the comparative example were 11.8 °, and a good result was obtained in which the angle change amount of the example was reduced to about half of that of the comparative example. The amount of eccentricity of the bearing portion obtained by calculation is 9 μm in the case of the example and 21 μm in the comparative example.

In the above-described embodiment, the rolling element of the bearing portion is a sphere, and the cross-sectional shape of the raceway groove is an arc shape in accordance with the sphere. However, the rolling element is a roller, and the cross-section of the raceway groove is adjusted to the roller. It can also be shaped.

[0045]

As described above, the pulley with a built-in clutch of the present invention uses a steel material containing retained austenite as a material of the inner member, and forms the inner member and the pulley or the outer member by two raceway grooves and rolling elements. And then tempered at a temperature higher than the martensitic transformation temperature of the steel material of the inner member, thereby transforming the retained austenite. The radial eccentricity of the bearing part caused by radial load is reduced by taking the radial clearance of the bearing part as a negative value by using the above, so the amount of angular change of the sprag during one rotation of the pulley is reduced, and the wear of the sprag is reduced. And durability can be improved. The pulley is separate from the outer member, and the separate pulley is tightly fitted on the outer diameter surface of the assembly to reduce the diameter of the outer portion.A combination of the diameter reduction effect and the effect of the transformation expansion is used. The radial gap can be a negative value.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a first embodiment.

FIG. 2 is a partially omitted cross-sectional view along the line II-II in FIG.

FIG. 3 is a longitudinal sectional view showing a second embodiment.

FIG. 4 is a partially omitted cross-sectional view taken along the line IV-IV in FIG. 3;

FIG. 5 is an exploded perspective view showing the cage of FIG. 3;

FIG. 6 is a development view of the bearing unit of FIG. 3;

FIG. 7 is a schematic diagram illustrating a change in the angle of a sprag.

FIG. 8 is a schematic diagram illustrating a change in the angle of a sprag.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Inner member 2 Outer member 3 Cage 3a Main body 3b Lid 4 Steel ball 5, 5a, 5b, 5c, 5d Sprag 6 Pulley 7, 8 Track groove 9, 10 Cylindrical surface 11 Pin 12 Pin hole 13 Pin 14 Spring ring 15, 16 Space 17 Grease 18, 19 Arc cylindrical surface 20 Spring piece 21 Stopper 22 Seal member 23 Inner member 24 Pulley 25 Cage 26 Steel ball 27 Sprag 28, 29 Track groove 30, 31 Cylindrical surface

Claims (4)

[Claims] 1. A steel groove having a raceway groove extending in the circumferential direction and an outer diameter surface having cylindrical surfaces on both sides thereof, a steel inner member attached to a shaft, and a steel inner member disposed outside the inner member, and having a circumferential direction. A steel pulley having a raceway groove connected to the inner member and an inner diameter surface provided with cylindrical surfaces on both sides thereof; a plurality of rolling elements fitted and held in both raceway grooves of the inner member and the pulley; In a pulley with a built-in clutch, comprising a plurality of sprags which are held between the inner surface of the inner member and the pulley astride a groove and are detachably disposed on the cylindrical surface, the inner member is formed of a material. The bearing portion is formed of a steel material in which the retained austenite is expanded by martensitic transformation after assembling with the pulley, and which is formed by the both raceway grooves and the rolling elements. Characterized in that the radial clearance of the pulley has a negative value. 2. A raceway groove extending in the circumferential direction and an outer diameter surface having cylindrical surfaces on both sides thereof, a steel inner member mounted on a shaft, and a steel inner member disposed outside the inner member, the outer circumferential surface being disposed in the circumferential direction. And a cylindrical steel outer member having an inner diameter surface provided with a cylindrical surface on both sides of the raceway groove, and a plurality of rolling elements fitted and held in both the raceway grooves of the inner member and the outer member. And a plurality of sprags that are held between the cylindrical surfaces of the inner member and the outer member so as to straddle the two raceway grooves, and are disposed so as to be able to be disengaged from the cylindrical surfaces, and an outer diameter surface of the outer member. In the pulley with a built-in clutch composed of a pulley fitted to the inner member, the material of the inner member includes residual austenite, and after assembly with the outer member, the residual austenite is transformed into martensite. Formed of expanded steel material
The clutch, wherein the pulley is tightly fitted to an outer diameter surface of the outer member, and a radial gap between a bearing portion formed by the both raceway grooves and the rolling element has a negative value. Built-in pulley. 3. A steel inner member having a raceway groove extending in the circumferential direction and an outer diameter surface having cylindrical surfaces on both sides thereof, the steel inner member being mounted on a shaft, and being disposed outside the inner member and being arranged in a circumferential direction. A steel pulley having a raceway groove connected to the inner member and an inner diameter surface having a cylindrical surface on both sides thereof; a plurality of rolling elements fitted and held in both raceway grooves of the inner member and the pulley; A method for manufacturing a clutch built-in pulley comprising a plurality of sprags straddling a groove and held between the inner surface of the inner member and a pulley, the inner member and the pulley being held between the inner surface and a pulley. Using steel containing residual austenite in the material of
The inner member and the pulley are assembled so that a radial gap between a bearing portion formed by the two raceway grooves and the rolling element has a small positive value. Thereafter, the assembled member is martensite of steel material of the inner member. A method for manufacturing a pulley with a built-in clutch, characterized in that a tempering process is performed at a temperature higher than a transformation temperature to make the radial gap a negative value. 4. A raceway groove extending in the circumferential direction and an outer diameter surface having cylindrical surfaces on both sides thereof, a steel inner member mounted on a shaft, and a steel inner member disposed outside the inner member, the circumferential direction being And a cylindrical steel outer member having an inner diameter surface provided with a cylindrical surface on both sides of the raceway groove, and a plurality of rolling elements fitted and held in both the raceway grooves of the inner member and the outer member. And a plurality of sprags that are held between the cylindrical surfaces of the inner member and the outer member so as to straddle the two raceway grooves, and are disposed so as to be able to be disengaged from the cylindrical surfaces, and an outer diameter surface of the outer member. In the method of manufacturing a clutch built-in pulley consisting of a pulley fitted to, using a steel material containing residual austenite as a material of the inner member, the radial gap of the bearing portion formed by the two raceway grooves and rolling elements The inner member and the outer member are assembled so as to have a small positive value, and then the assembly is tempered at a temperature higher than the martensitic transformation temperature of the steel material of the inner member, and the pulley is fixed to the outer member. A method for manufacturing a pulley with a built-in clutch, wherein the radial gap is set to a negative value by tightly fitting the outer diameter surface of the member.