JP2009068682A - Cross groove type uniform universal joint - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cross groove type uniform universal joint which can exhibit a stable function even when a large operation angle is taken for preventing the instability of a torque transmission ball. <P>SOLUTION: The cross groove type uniform universal joint has an inner race 2 to circumferentially form ball grooves 2a, 2b by turns which incline in the opposite direction mutually and the outer race 4 which circumferentially forms the ball grooves 4a, 4b by turns which incline to the opposite direction mutually. The torque transmission ball 6 is built into the intersection part of the ball grooves 2a, 2b, 4a, 4b of the inner race 2 and the outer race 4 which incline to the opposite direction mutually and the cage 8 to retain the torque transmission ball 6 is provided with. The size L in the axial direction of the pocket 81 formed in a cage 8 is made smaller than diameter ϕd of the torque transfer ball 6 and the torque transmission ball 6 is retained stably in the pocket 81 by the mutual interference. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a constant velocity universal joint used in a power transmission device of an automobile or various industrial machines, and more particularly, a cross groove type constant velocity universal joint having a ball groove in which an inner ring and an outer ring are inclined in opposite directions with respect to an axis. About.

  In the cross groove type constant velocity universal joint, the ball groove of the inner ring and the ball groove of the outer ring that form a pair are inclined in opposite directions with respect to the axis, and the torque transmission ball is held at the intersection of both ball grooves. ing. Because of such a structure, rattling between the torque transmitting ball and the ball groove can be reduced, and in particular, it is used for a drive shaft and a propeller shaft of an automobile that does not like rattling.

  Non-Patent Document 1 shows the most basic cross groove type constant velocity universal joint. In Non-Patent Document 1, the number of rolling elements is four or more, and generally six, and the inclination angle between the ball grooves is the opposite of the inner ring and the outer ring with the constant velocity universal joint taking the maximum operating angle. It is assumed that the ball grooves to be designed are designed so as not to be parallel, and the intersection angle with the axis of each inner ring or outer ring is generally 13 to 19 °. Moreover, it is described that the cross section of the groove is a gothic arch, and the groove diameter is generally 1.01 to 1.04 times the ball diameter. Furthermore, it is described that the contact angle is 30 to 45 °.

The above constant-velocity universal joint with six rolling elements has a maximum torque when the joint is bent and returned to the opposite direction without rotating. In the worst case, the joint is angled. It will not return, that is, it will be caught. This catch has a problem of deteriorating workability when the constant velocity universal joint is assembled to the vehicle. In order to solve this problem, Patent Documents 2 to 4 propose that the number of torque transmission balls be larger than six.
ERWagner, Universal Joint and Driveshaft Design Manual, Section 3.2.12: Cross Groove Universal Joint, SAE, 1991, p.163-166 JP 2006-132669 A JP 2006-266423 A JP 2006-266424 A

  Cross groove type constant velocity universal joints have a larger operating angle than constant velocity universal joints that control torque transmitting balls by offsetting the center of the arc-shaped ball grooves formed in the axial direction on the inner and outer rings. I can't take it. This is because when the operating angle is increased, the wedge angle formed at the intersection of the inner and outer ring ball grooves forming a pair is reversed, and the force acting on the torque transmitting ball from the intersection is reduced. This is because the balance of force between the torque transmitting ball and the cage is lost. As a result, the cage becomes unstable because it cannot maintain the balance of force with other torque transmission balls. The cage pocket is larger than the ball diameter in order to increase the degree of freedom of rotation of the torque transmission ball, so the torque transmission ball also becomes unstable, and in the worst case, it functions as a constant velocity universal joint. There is a risk of being lost.

  Accordingly, an object of the present invention is to provide a cross-groove type constant velocity universal joint that can prevent the torque transmission ball from becoming unstable and can exhibit a stable function even when the operating angle is large.

  In order to achieve the above object, a cross groove type constant velocity universal joint according to the present invention includes an inner ring having outer circumferential surfaces in which ball grooves inclined in opposite directions with respect to an axis are alternately formed in a circumferential direction, and an axis. At the intersection of an outer ring having inner circumferential surfaces alternately formed in the circumferential direction with ball grooves inclined in opposite directions, and an inner ring ball groove and an outer ring ball groove inclined in opposite directions with respect to the axis. In a cross groove type constant velocity universal joint having an incorporated torque transmission ball and a cage that is interposed between an outer peripheral surface of the inner ring and an inner peripheral surface of the outer ring and holds the torque transmission ball at a predetermined interval in the circumferential direction. The cage is characterized in that the pocket for accommodating the torque transmission ball is formed smaller than the diameter of the torque transmission ball.

  According to the above configuration, since the size of the pocket for accommodating the torque transmission ball of the cage is formed smaller than the diameter of the torque transmission ball, a tightening margin is formed between the pocket and the torque transmission ball, The torque transmitting ball is stably held in the cage pocket. As a result, the torque transmission ball in the ball groove whose crossing angle is reversed is stably held in the pocket, and as a result, the disadvantage that the function of the constant velocity universal joint is lost can be prevented.

  The cross groove type constant velocity universal joint according to a second aspect of the present invention is the cross groove type constant velocity universal joint according to the first aspect, wherein the pocket has a dimension in the cage axis direction smaller than the diameter of the torque transmitting ball. It is a thing.

  According to the above embodiment, the pocket has a dimension in the cage axis direction smaller than the diameter of the torque transmission ball, so that the inner peripheral surface facing the cage axial direction of the pocket, and the outer peripheral surface of the torque transmission ball An allowance is formed between the two. Therefore, even if the crossing angle of the ball grooves of the inner and outer rings that make a pair is reversed and the force acting on the torque transmission ball from the intersection of the ball grooves is reduced, the torque transmission ball is The position in the axial direction is stably maintained. Therefore, destabilization of the torque transmission ball is prevented, and the disadvantage that the function of the constant velocity universal joint is lost can be prevented.

  A cross groove type constant velocity universal joint according to a third aspect of the present invention is the cross groove type constant velocity universal joint according to the second aspect, wherein the pocket has a dimension in the cage axis direction and the diameter of the torque transmitting ball. A fastening allowance of 0 μm or more and 15 μm or less is formed.

  According to the above embodiment, by forming an appropriate tightening allowance between the torque transmission ball and the axial dimension of the cage pocket, the sliding resistance of the torque transmission ball can be appropriately maintained. Here, if the tightening allowance is smaller than 0 μm, it is difficult to stably hold the torque transmitting ball in the cage pocket when the intersection angle of the ball grooves is reversed. On the other hand, if the tightening allowance is larger than 15 μm, the sliding resistance of the torque transmission ball is increased, which may cause wear or damage of the ball groove and the torque transmission ball.

  A cross groove type constant velocity universal joint according to a fourth aspect of the present invention is the cross groove type constant velocity universal joint according to the first aspect, wherein the number of the torque transmitting balls is eight or ten.

  According to the above-described embodiment, even if the crossing angle of the ball grooves of the predetermined inner ring is reversed, the cage is stably held by the torque transmission balls of other ball grooves whose crossing angles are not reversed. Since the number of torque transmitting balls is 8 or 10, the number of torque transmitting balls in the ball groove where the crossing angle is not reversed is large, and the cage is effectively stabilized. Therefore, the torque transmission ball in the ball groove whose public crossing angle is reversed is stably held in the pocket, and as a result, the disadvantage that the function of the constant velocity universal joint is lost can be effectively prevented.

  In addition, by setting the number of torque transmission balls to 8 or 10, it is possible to increase the torque transmission efficiency, which is the main function of the joint, compared to the case where the number of torque transmission balls is six.

  According to the present invention, since the torque transmission ball is stably held in the cage pocket, a cross groove type constant velocity universal joint that exhibits a stable torque transmission function even at a relatively large operating angle can be obtained.

  An embodiment of the present invention will be described with reference to the drawings. FIG. 1A is a cross-sectional view showing a disk-type cross groove constant velocity universal joint, and FIG. 1B is a cross sectional view of the cross groove constant velocity universal joint shown in FIG. It is a front view which shows a mode observed from the end surface side. In addition to the disk type, the cross groove type constant velocity universal joint includes a flange type and a bell type.

  This cross groove type constant velocity universal joint includes an inner ring 2, an outer ring 4, a torque transmission ball 6, and a cage 8 as main components. In this cross groove type constant velocity universal joint, an inner ring 2 is coupled to a first shaft 12 (shaft), and a boot 11 with an adapter for sealing the inside is attached to the first shaft 12 and the constant velocity universal joint. Yes. A second shaft (shaft) (not shown) provided with a companion flange is coupled to the end of the outer ring 4 of the constant velocity universal joint. An end plate 10 that is located between the companion flange of the second shaft and the constant velocity universal joint and seals the inside is attached to the end of the outer ring 4.

  The inner ring 2 has a spline hole 21 at the center, and a plurality of ball grooves 2a and 2b are formed on a spherical outer peripheral surface. The first shaft 12 is fitted into the spline hole 21 of the inner ring 2 so that torque can be transmitted, and the first shaft 12 is attached to the inner ring by a snap ring or a circlip attached to the ring groove of the first shaft 12. 2 is fixed in the axial direction. The outer ring 4 is located on the outer periphery of the inner ring 2, and the same number of ball grooves 4a and 4b as the ball grooves 2a and 2b of the inner ring 2 are formed on the inner peripheral surface.

  Between the one end of the outer ring 4 in the axial direction and the first shaft 12, the inside of the constant velocity universal joint is provided to prevent leakage of grease filled in the constant velocity universal joint and to prevent foreign matter from entering from the outside. A boot 11 with an adapter that seals from one end side is attached. The boot 11 with an adapter includes a boot body made of a bellows-like rubber or resin having a small diameter end portion and a large diameter end portion, and a metal adapter having a cylindrical portion at one end portion. The large-diameter end of the boot body is joined to the other end of the adapter, the small-diameter end of the boot body is fastened to the first shaft 12 by a boot band, and one end of the adapter is connected to one end of the outer ring 4 They are fitted and fixed to the outer ring 4 with bolts 13.

  Between the other end in the axial direction of the outer ring 4 and the companion flange of the second shaft (not shown), in order to prevent leakage of grease filled in the constant velocity universal joint and prevent entry of foreign matter from the outside, etc. An end plate 10 for sealing the inside of the quick universal joint from the other end side is mounted. The cylindrical portion of the end plate 10 is fitted to the other end portion of the outer ring 4, and is fixed by a bolt 13 while being sandwiched between the companion flange and the other end portion of the outer ring 4.

  FIG. 2 is a developed view of the ball groove, and as indicated by a solid line in FIG. 2, the ball grooves 2a and 2b inclined in opposite directions with respect to the axis of the inner ring 2 are alternately positioned in the circumferential direction. . Further, as indicated by a two-dot chain line, ball grooves 4 a and 4 b inclined in opposite directions with respect to the axis of the outer ring 4 are alternately positioned in the circumferential direction. A symbol β is an intersection angle of each ball groove 2a, 2b, 4a, 4b with respect to the axis. The ball grooves 2a, 2b, 4a, 4b of the inner ring 2 and the outer ring 4 generally have a Gothic arch or elliptical cross-sectional shape, and the relationship between the torque transmitting ball 6 and the ball grooves 2a, 2b, 4a, 4b is Angular contact. The contact angle of the angular contact is in the range of 30 to 50 °, for example.

  The torque transmitting ball 6 is incorporated at the intersection of the ball groove 2a and the ball groove 4a or the ball groove 2b and the ball groove 4b that form a pair. As shown in FIG. 1B, here, there are six ball grooves 2a, 2b of the inner ring 2, six ball grooves 4a, 4b of the outer ring 4, and six torque transmission balls 6. The torque transmission ball 6 is held in a pocket of a cage 8 interposed between the inner ring 2 and the outer ring 4.

  3A is a transverse sectional view of the cage 8, and FIG. 3B is a longitudinal sectional view taken along the line AA of the cage 8 in FIG. 3A. Fig.3 (a) is the BB line of FIG.3 (b).

  As shown in FIG. 3A, the cage 8 is formed with the same number of window-like pockets 81 that accommodate and hold the torque transmission balls 6 as the number of torque transmission balls 6 at equal intervals in the circumferential direction. A portion between adjacent pockets is a column portion 82. The outer peripheral surface 83 of the cage 8 is spherical, and the inner peripheral surface of the outer ring 4 is a guide surface for the outer peripheral surface 83 of the cage 8. The inner peripheral surface 84 of the cage 8 is also spherical, and the outer peripheral surface of the inner ring 2 serves as a guide surface for the inner peripheral surface 84 of the cage 8.

  The pocket 81 of the cage is formed in a long hole shape whose circumferential dimension is longer than the axial dimension. A pair of inner peripheral surfaces 81a facing each other in the axial direction of the pocket 81 are formed in parallel to each other. A pair of inner peripheral surfaces 81 b facing the circumferential direction of the pocket 81 is formed in a curved surface generally along the outer peripheral surface of the torque transmission ball 6. The inner peripheral surfaces 81 a and 81 b of the pocket 81 are formed in parallel with a diameter passing through the center of the pocket 81 in the circumferential direction.

  As shown in FIG. 3B, the dimension L in the axial direction of the pocket 81 is smaller than the diameter φd of the torque transmission ball 6. Specifically, a fastening allowance of 0 μm or more and 15 μm or less is formed between the dimension L in the axial direction of the pocket 81 and the diameter φd of the torque transmission ball 6. Thereby, the movement of the torque transmitting ball in the pocket 81 is suppressed. Further, by making the interference between the dimension L in the axial direction of the pocket 81 and the diameter φd of the torque transmission ball 6 between 0 μm and 15 μm, it is possible to prevent the slide resistance of the torque transmission ball 6 from deteriorating.

  When the cross groove type constant velocity universal joint having the above configuration is operated, when the operating angle is 0 °, the wedge angle formed at the intersection between the paired inner ring ball grooves 2a and 2b and the outer ring ball grooves 4a and 4b. By the action of 2β, the rotational force in the circumferential direction and the component force in the axial direction act on the torque transmitting ball 6 from the ball grooves 2a, 2b, 4a, 4b. The axial force received by each torque transmitting ball 6 acts on the cage 8, and the axial force balances in the cage 8 and is held in the same plane as the inner ring 2 and the outer ring 4. When the operating angle increases and the crossing angle β of the inner and outer ring ball grooves forming a pair becomes 0, the crossing portions of the inner and outer ring ball grooves 2a, 2b, 4a and 4b disappear and act on the torque transmitting ball 6. The axial force is almost zero. Here, in the present embodiment, the torque transmitting ball 6 is engaged with the torque transmitting ball 6 from the ball grooves 2a, 2b, 4a, 4b by being fitted to the inner peripheral surface 81a opposed to the axial direction of the pocket 81. The torque transmitting ball 6 is held at a predetermined position in the cage 8 even if the axial force is lost. Therefore, it is possible to prevent the torque transmission ball 6 from becoming unstable due to the reversal of the crossing angle β of the ball grooves 2a, 2b, 4a, 4b, thereby preventing the problem of losing the function of the constant velocity universal joint.

  In the above embodiment, the number of the ball grooves 2a, 2b, 4a, 4b of the inner / outer rings 2, 4 and the torque transmitting balls 6 accommodated therebetween are six, but the ball grooves 2a, 2b, 4a, 4b The number of torque transmission balls 6 may be an appropriate number such as 8 or 10. By setting the number of the ball grooves 2a, 2b, 4a, 4b and the torque transmission balls 6 to 8 or 10, the torque transmission loss when the ball grooves 2a, 2b, 4a, 4b form the same crossing angle. Can be reduced. Here, when the number of ball grooves 2a, 2b, 4a, 4b increases, ball groove interference occurs in the circumferential direction, so the maximum value of the crossing angle β that can be set for the ball grooves 2a, 2b, 4a, 4b is reduced. For this reason, the inversion of the crossing angle β is likely to occur. However, according to the present embodiment, since the torque transmission ball 6 is stably held in the axial direction of the pocket 81, the torque transmission ball 6 can be prevented from becoming unstable even if the cross angle is reversed. That is, a cross groove type constant velocity universal joint can be obtained in which the operating angle can be relatively large, the backlash is small, and the torque transmission loss is small.

FIG. 1A is a cross-sectional view of the cross groove type constant velocity universal joint of the embodiment, and FIG. 1B is a front view of the cross groove type constant velocity universal joint. It is a development view of a ball groove of a cross groove type constant velocity universal joint. 3A is a transverse sectional view of the cage, and FIG. 3B is a longitudinal sectional view of the cage.

Explanation of symbols

2 Inner ring 2a, 2b Ball groove 4 Outer ring 4a, 4b Ball groove 6 Torque transmission ball 8 Cage 81 Pocket 81a, 81b Pocket inner circumference L Pocket axial dimension φd Diameter of torque transmission ball

Claims (4)

An inner ring having an outer peripheral surface alternately formed in the circumferential direction with ball grooves inclined in opposite directions with respect to the axis, and an inner ring having ball grooves inclined in the opposite directions with respect to the axis in the circumferential direction. An outer ring having a peripheral surface, a torque transmitting ball incorporated at the intersection of the ball groove of the inner ring and the ball groove of the outer ring inclined in opposite directions with respect to the axis, and the outer peripheral surface of the inner ring and the inner peripheral surface of the outer ring. In a cross groove type constant velocity universal joint having a cage interposed between and holding a torque transmission ball at a predetermined interval in the circumferential direction,
A cross-groove type constant velocity universal joint characterized in that a size of a pocket for accommodating a torque transmission ball of the cage is smaller than a diameter of the torque transmission ball. In the cross groove type constant velocity universal joint according to claim 1,
A cross-groove type constant velocity universal joint characterized in that a dimension of the pocket in the cage axis direction is smaller than a diameter of the torque transmitting ball. In the cross groove type constant velocity universal joint according to claim 2,
A cross-groove type constant velocity universal joint characterized in that an interference of 0 μm or more and 15 μm or less is formed between a dimension of the pocket in the cage axis direction and a diameter of the torque transmission ball. In the cross groove type constant velocity universal joint according to claim 1,
A cross groove type constant velocity universal joint, wherein the number of torque transmitting balls is eight or ten.

Images