JPH1182690A - Pulley integrated with clutch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pulley integrated with a clutch and its manufacturing method, which can make its bearing part small in eccentricity, and is excellent in durability. SOLUTION: Assembly is so performed that a radial gap at a bearing part formed out of two tracking grooves 7 and 8, and of a steel ball 4, is made to be of a small positive value in a state that an inner member 1 and an outer member 2 are assembled with each other, and a pulley 6 is firmly tightened with the aforesaid assembly. By making the radial gap of this product to be of a negative value, the quantity of eccentricity of the bearing part caused by radial load is made small, the angular variation of a sprag 5 while the pulley 6 is rotated once, is also made small so as to allow the wear of the sprag 5 to be reduced, and the durability of the pulley integrated with a clutch is thereby enhanced.

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. 1 to 4 showing an embodiment of the present invention. As shown in FIGS. 1 and 2, this pulley with a built-in clutch includes an inner member 1 attached to a shaft, a cylindrical outer member 2 disposed outside the inner member 1, and an inner member 1. It is basically composed of a plurality of steel balls 4 and sprags 5 held and incorporated by a retainer 3 therebetween, 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. 3, the retainer 3 has a retainer body 3a made of synthetic resin and a lid 3b made of synthetic resin.
A plurality of pins 11 are formed on one end side in the axial direction of the retainer main body 3a, and each of these pins 11 is fitted into a pin hole 12 provided in the lid 3b to be integrated. I have. Also, a plurality of pins 13 are formed on the other end side in the axial direction of the retainer main body 3a.
A ring spring 14 described below is attached.

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. 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. 10 are formed with arcuate cylindrical surfaces 18 and 19 (FIG. 2).

As shown in FIG. 4, the same number of spring pieces 20 as the sprags 5 are formed in the ring spring 14 by cutting and raising, and each spring piece 20 is opened through a window provided in the retainer body 3a. The sprags 5 are inserted into the space 16 for accommodating the sprags 5 and press the sprags 5. By this pressing, the respective arcuate cylindrical surfaces 18 and 19 of the sprags 5 cause the respective cylindrical surfaces 9, 10 Is in contact with

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 transmitted by a belt (not shown) to rotate in the direction of the arrow in FIG.

When the pulley 6 is rotated in the direction of the arrow in FIG. 2, the outer member 2 is also integrally rotated 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. 5 is a schematic diagram when there is no eccentricity, and FIG. 6 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. 5, the point at which each sprag 5 contacts the cylindrical surface 9 is P, the point at which the sprags 5 contact 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. 6, 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. Therefore, 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. 6 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 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. 6, since the signs βa and βc have opposite signs, the angle change 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 clutch built-in pulley bearing deteriorates the bearing and reduces 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 an inner race which has a raceway groove extending in the circumferential direction and an outer diameter surface provided with cylindrical surfaces on both sides thereof. A member and the outer member,
A cylindrical outer member having a raceway groove continuous in the circumferential direction and an inner diameter surface provided with a cylindrical surface on both sides thereof; and a plurality of rolling elements fitted and held in both raceway grooves of the inner member and the outer member. A plurality of sprags which are held between the cylindrical surfaces of the inner member and the outer member over the two raceway grooves, and which 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 clutch built-in pulley including the fitted pulley, the pulley is tightly fitted to the 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 is set to a negative value. It was adopted.

In manufacturing the above-mentioned clutch built-in pulley, a radial gap between a bearing portion formed by the two raceway grooves and the rolling element is assembled so as to have a small positive value. In this case, a method of tightly fitting the pulley on the outer diameter surface of the outer member is adopted so as to obtain the following value.

That is, the radial gap between the bearing portions formed by the two raceway grooves and the rolling elements is previously assembled so as to have a small positive value, and then the pulley is tightly fitted to the outer diameter surface of the outer member. By setting the radial gap of the bearing portion to a negative value, it is possible to prevent eccentricity due to backlash of the bearing portion caused by a radial load applied by belt 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. Note that the negative radial gap is as small as about −10 μm, and the rolling element is not locked in the raceway groove in such a negative radial gap.

[0027]

Embodiments of the present invention will be described below. As shown in FIGS. 1 and 2, the pulley with a built-in clutch according to the embodiment includes an inner member 1, a cylindrical outer member 2, a plurality of steel balls 4 incorporated between these two members 1 and 2, and It is basically composed of a sprag 5 and a pulley 6 fitted on the outer diameter surface of the outer member 2,
On the outer diameter surface of the inner member 1 and the inner diameter surface of the outer member 2, there are track grooves 7, 8 continuous in the circumferential direction of an arc-shaped cross section, and cylindrical surfaces 9, 10 on both sides of these track grooves 7, 8. Is provided. The plurality of steel balls 4 are fitted into the two raceway grooves 7 and 8 to form a bearing portion, and the plurality of sprags 5 are arranged across the two raceway grooves 7 and 8.

In this pulley with a built-in clutch, the radial gap between the bearing portions formed by the two raceway grooves 7 and 8 and the steel ball 4 when the inner member 1 and the outer member 2 are assembled is 20 μm. The pulley 6 is 40 μm
Of the outer member 2
Has a reduced inner diameter of 30 μm, and the radial gap of the final product is −10 μm. The groove diameter of the belt groove of the pulley with a built-in clutch is 60 mm, and the outer diameter of the inner member 1 is 40 mm.

Examples and comparative examples will be described below.

[0030]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The radial gap manufactured by the above-described method is -1.
A pulley with a built-in clutch of 0 μm was prepared.

[0031]

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 sprag 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 about 9 μm in the case of the embodiment and about 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 conformity with the sphere. However, the rolling element is a roller, and the cross-section of the raceway groove is adjusted to this roller. It can also be shaped.

[0036]

As described above, the pulley with a built-in clutch of the present invention has a small positive clearance between the bearing portion formed by the two raceway grooves and the rolling element in a state where the inner member and the outer member are assembled. Assemble so that
A pulley is tightly fitted on the pulley, and the radial gap of the product is set to a negative value to reduce the eccentricity of the bearing caused by the radial load. Etc. can be reduced, and the durability can be improved.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing an embodiment of a pulley with a built-in clutch.

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

FIG. 3 is an exploded perspective view showing the cage of FIG. 1;

FIG. 4 is a development view of the bearing unit of FIG. 1;

FIG. 5 is a schematic diagram illustrating a change in the angle of a sprag.

FIG. 6 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 Ring spring 15, Reference Signs List 16 space 17 grease 18, 19 arcuate cylindrical surface 20 spring piece 21 stopper 22 seal member

Claims (2)

[Claims] 1. An orbiting groove having a circumferentially continuous raceway groove and an outer diameter surface having cylindrical surfaces on both sides thereof, an inner member attached to a shaft, and a raceway arranged outside the inner member and continuous in a circumferential direction. A cylindrical outer member having a groove and an inner diameter surface provided with 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 outer member; A plurality of sprags which are held between the cylindrical surfaces of the inner member and the outer member so as to be capable of engaging and disengaging from the cylindrical surfaces, and a pulley fitted to an outer diameter surface of the outer member. In the pulley with a built-in clutch, 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. Pulley with a built-in clutch. 2. An orbital groove having a circumferentially continuous raceway groove and an outer diameter surface having cylindrical surfaces on both sides thereof, an inner member attached to a shaft, and a raceway arranged outside the inner member and continuous in a circumferential direction. A cylindrical outer member having a groove and an inner diameter surface provided with 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 outer member; A plurality of sprags which are held between the cylindrical surfaces of the inner member and the outer member so as to be capable of engaging and disengaging from the cylindrical surfaces, and a pulley fitted to an outer diameter surface of the outer member. In the method of manufacturing a pulley with a built-in clutch, the radial gap of the bearing portion formed by the two raceway grooves and the rolling elements is assembled to have a small positive value, and then the radial gap is set to a negative value. A method of manufacturing a pulley with a built-in clutch, wherein the pulley is tightly fitted to an outer diameter surface of the outer member.