JP2010054002A - Double offset type constant velocity universal joint - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce resistance due to grease or air during plunging. <P>SOLUTION: This double offset type constant velocity universal joint comprises an outer ring 10 having ball grooves 16 formed at circumferentially equal spaces axially extending to a cylindrical inner peripheral face 14, an inner ring 20 having ball grooves 26 formed at circumferentially equal spaces axially extending to a spherical outer peripheral face 24, balls 30 laid between the ball groove 16 of the outer ring 10 and the ball groove 26 of the inner ring 20 paired with each other, and a cage 40 laid between the inner peripheral face 14 of the outer ring 10 and the outer peripheral face 24 of the inner ring 20 for holding the balls 30. Herein, communication passages 15, 17, 27 are provided which can be not only angle-displaced but also axially displaced between the outer ring 10 and the inner ring 20 for allowing the movement of grease or air between the corner side and the opening side inside the outer ring during axial displacement. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a double offset type constant velocity universal joint used in a power transmission device for automobiles and various industrial machines.

  Constant velocity universal joints are broadly classified into fixed types that can only be angularly displaced and sliding types that are capable of not only angular displacement but also axial displacement (plunging), and double offset type constant velocity universal joints belong to the latter.

As shown in FIG. 5, the double offset type constant velocity universal joint includes an outer ring 10, an inner ring 20, a ball 30, and a cage 40. In order to reduce sliding resistance during plunging, the spherical shape and pockets of the cage 40 are used. Some have a devised shape (Patent Documents 1 and 2).
Japanese Utility Model Publication No. 63-2665 Japanese Patent Laid-Open No. 3-51519

  In addition to the rolling resistance of the ball, the following causes can be considered as the cause of the increase in slide resistance. That is, as shown in FIG. 5, there is no large gap in the ball center cross section (FIG. 5B) in the state where the outer ring 10, the inner ring 20, the ball 30 and the cage 40 are assembled. Since air movement is difficult, this becomes a great resistance when sliding.

  In the case of an automobile, the clip 19 may not be attached to the outer ring 10 when attached to the automobile. In that case, if the cassette (inner ring 20, ball 30, cage 40) falls off from the outer ring 10, it is difficult to move grease and air in the outer ring 10, and therefore the cassette cannot be inserted into the outer ring 10 again. difficult.

  Therefore, a main object of the present invention is to eliminate the above-mentioned problems and enable plunging with a small resistance.

  The present invention solves the problem by providing a communication passage that allows quick movement of grease and air when the sliding type constant velocity universal joint is displaced in the axial direction (plunging) or when the cassette is assembled to the outer ring. .

That is, according to the present invention, an outer ring in which ball grooves extending in the axial direction are formed on the cylindrical inner peripheral surface at equal intervals in the circumferential direction, and a ball groove extending in the axial direction on the spherical outer peripheral surface are provided in the circumferential direction, etc. An inner ring formed at a distance, a ball interposed between a ball groove of a pair of outer rings and a ball groove of the inner ring, and a cage interposed between the inner peripheral surface of the outer ring and the outer peripheral surface of the inner ring to hold the balls In a double offset type constant velocity universal joint that is capable of not only angular displacement but also axial displacement between the outer ring and the inner ring, between the inner side of the outer ring and the opening side during the axial displacement. A communication passage that allows the movement of grease and air is provided. Since grease and air in the outer ring can move quickly through the communication passage, reduction of slide resistance and improvement of handling can be achieved.
The connecting passage allows smooth movement of grease and air so that the cassette (inner ring, ball, cage) can move with less resistance in the outer ring when the sliding constant velocity universal joint is displaced in the axial direction (plunging). Therefore, the cross-sectional area and the like should be set from this viewpoint. As a specific example, it is preferable that the total cross-sectional area of the communication passage is 1 mm ² or more.

  According to a second aspect of the present invention, in the double offset constant velocity universal joint according to the first aspect, the communication passage is provided at the bottom of the ball groove.

  According to a third aspect of the present invention, in the double offset constant velocity universal joint of the second aspect, the ball groove is a ball groove of an outer ring, a ball groove of an inner ring, or both ball grooves.

  According to a sixth aspect of the present invention, in the double offset constant velocity universal joint according to any one of the first to fifth aspects, the communication passage is provided on the inner peripheral surface of the outer ring.

  According to a fourth aspect of the present invention, in the double offset constant velocity universal joint according to any one of the first to third aspects, the communication passage is provided on the outer peripheral surface of the inner ring.

  The invention according to claim 5 is the double offset type constant velocity universal joint according to any one of claims 1 to 4, wherein the connecting passage is provided on an outer peripheral surface or an inner peripheral surface of the cage. .

  A seventh aspect of the present invention is the double offset type constant velocity universal joint according to any one of the first to sixth aspects, wherein the communication passage is provided by machining. Since machining can be performed with high accuracy, there are the following advantages. That is, the thickness of the outer ring, the inner ring, and the cage can be accurately managed, and a stable strength can be obtained. In addition, since the minimum required processing amount can be set, the contact area between the inner diameter of the outer ring and the outer diameter of the cage and the outer diameter of the inner ring and the inner diameter of the cage can be ensured accurately, and stable durability can be obtained.

  The invention according to claim 8 is the double offset type constant velocity universal joint according to any one of claims 1 to 6, wherein the communication passage is provided by plastic working. Specific examples of plastic working include cold forging, hot forging, and pressing. According to plastic working, the communication passage can be provided at a relatively low cost.

  The invention according to claim 9 is the double offset type constant velocity universal joint according to any one of claims 1 to 8, wherein the ball groove of the outer ring or the ball groove of the inner ring or both are cold forged. Is. By making the ball grooves cold forged, post-processing can be abolished, contributing to cost reduction.

  The invention of claim 10 is the double offset type constant velocity universal joint according to any one of claims 1 to 8, characterized in that the inner peripheral surface of the outer ring is forged. By forging the inner peripheral surface of the outer ring, post-processing can be abolished, contributing to cost reduction.

  According to this invention, during plunging, grease and air can be easily and quickly moved between the inner side of the outer ring and the opening side through the communication passage. Therefore, in addition to the reduction in slide resistance, the handling at the time of disassembly / reassembly is improved. Moreover, it contributes also to weight reduction by providing a communication channel. Furthermore, the effect of improving the intervention of grease can be expected.

Embodiments of the present invention will be described below with reference to the drawings.
First, a basic configuration will be described with reference to FIG. 1. A double offset type constant velocity universal joint includes an outer ring 10 as an outer joint member, an inner ring 20 as an inner joint member, and a ball 30 as a torque transmission element. The cage 40 for holding the ball is a main component.

  The outer ring 10 includes a mouse portion 12 and a stem portion 18, and is connected to a drive shaft or a driven shaft by a spline (or serration, the same applies hereinafter) shaft portion of the stem portion 18 so that torque can be transmitted. The mouth portion 12 is cup-shaped with one end open, has a cylindrical inner peripheral surface 14, and ball grooves 16 extending in the axial direction are formed at equal intervals in the circumferential direction of the inner peripheral surface 14.

  The inner ring 20 is connected to the driven shaft or the drive shaft through a spline hole 22 formed in the shaft center portion so that torque can be transmitted. The outer peripheral surface 24 of the inner ring 20 is spherical, and ball grooves 26 extending in the axial direction are formed at equal intervals in the circumferential direction of the outer peripheral surface 24.

  The ball groove 16 of the outer ring 10 and the ball groove 26 of the inner ring 20 form a pair, and one ball 30 is incorporated between each pair of ball grooves 16 and 26. The number of the balls 30 used in one joint, and therefore also the number of the ball grooves 16, 26 is arbitrary, but here, the case of 6 is illustrated.

  The cage 40 has pockets 46 in the form of through holes formed at predetermined intervals in the circumferential direction, and one ball 30 is accommodated in each pocket 46. Therefore, all balls 30 are held in the same plane by the cage 40.

The cage 40 is interposed between the outer ring 10 and the inner ring 20. The outer peripheral surface of the cage 40 is in contact with the cylindrical inner peripheral surface 14 of the outer ring 10 at a spherical portion 42. The inner peripheral surface of the cage 40 is in contact with the spherical outer peripheral surface 24 of the inner ring 20 at a spherical portion 44. The center O ₁ of the spherical surface portion 42 of the outer peripheral surface of the cage 40 and the center O ₂ of the spherical surface portion 44 of the inner peripheral surface are offset from the angular center O of the joint by an equal distance in opposite directions (double offset). ). Therefore, when the torque is transmitted in a state where the rotation axis of the outer ring 10 and the rotation axis of the inner ring 20 form an angle (operating angle θ), the cage 40 orients the ball 30 in a plane that bisects the operating angle θ. Play a role.

  Usually, a retaining device is provided at the opening end of the mouse portion 12 so that the cassette (20, 30, 40) does not fall off from the outer ring 10. Here, the case where the retaining device is configured by attaching the clip 19 to the circumferential groove formed on the inner peripheral surface of the opening end portion of the mouth portion 12 of the outer ring 10 is illustrated.

  Although not shown in the figure, in order to prevent leakage of lubricating grease, it is common to use a flexible boot. In the case of a constant velocity universal joint for automobiles, in addition to preventing intrusion of water and foreign matter, it also serves to protect against collisions of pebbles and the like.

  1 and 2 are examples in which axial grooves 15, 17, and 27 are formed in the inner peripheral surface 14 of the outer ring 10, the bottom of the ball groove 16, and the bottom of the ball groove 26 of the inner ring 20 to form a communication passage. Although the example in which the communication passage extends in the axial direction is shown, it may be inclined with respect to the axial line. Moreover, it does not necessarily need to be linear.

  FIG. 3 shows an example in which a cut-out 48 is formed in the spherical portion 42 on the outer peripheral surface of the cage 40 to form a communication passage. Although illustration is omitted, a groove that communicates between both ends in the axial direction may be formed on the inner peripheral surface 44 of the cage 40.

  FIG. 4 shows an example in which a hole 28 that penetrates the inner ring 20 in the axial direction is formed as a communication passage. Although illustration is omitted, a groove that communicates between both ends in the axial direction may be formed on the outer peripheral surface 24 of the inner ring 20.

The communication passages 15, 17, 27, 48, and 28 having various forms such as the above-described grooves, cut-throughs, and holes are open to the inner side of the outer ring 10 and the opening when the sliding type constant velocity universal joint is displaced in the axial direction (plunging). This is to allow smooth movement of grease and air so that the cassette (20, 30, 40) can move with less resistance between the sides, so the cross-sectional area should be set from this point of view. It is. Specifically, the total cross-sectional area of the communication passage is preferably 1 mm ² or more. In addition, as long as the above-described object can be achieved and there are no restrictions on processing, it is not limited to those extending parallel to the axis or linear, as in the illustrated example, but inclined. Various shapes can be adopted.

  The communication passage can be provided by machining. Since machining can be performed with high accuracy, the thickness of the outer ring, inner ring, and cage can be managed accurately, and a stable strength can be obtained. In addition, since the minimum required processing amount can be set, the contact area between the inner diameter of the outer ring and the outer diameter of the cage and the outer diameter of the inner ring and the inner diameter of the cage can be ensured accurately, and stable durability can be obtained.

  Further, the communication passage can be provided by plastic working such as cold forging, hot forging, and pressing. According to plastic working, the communication passage can be provided at a relatively low cost.

  The ball groove of the outer ring or the ball groove of the inner ring or both may be cold forged. The inner peripheral surface of the outer ring may be forged. In any case, post-processing can be abolished, which can contribute to cost reduction.

  The various embodiments described herein can be practiced alone or in combination. In addition, although an example is shown in which the distribution is performed in the circumferential direction in consideration of the rotation balance, one or any of a plurality of communication passages can be arranged at arbitrary intervals.

(A) is a longitudinal sectional view of a double offset type constant velocity universal joint, and (B) is a transverse sectional view. It is the elements on larger scale of FIG.1 (B). (A) is a longitudinal sectional view of the cage, (B) is an end view of the cage. It is an end view of an inner ring. (A) is a longitudinal sectional view of a conventional double offset type constant velocity universal joint, and (B) is a transverse sectional view.

Explanation of symbols

10 Outer ring (outer joint member)
12 Mouse part 14 Inner peripheral surface 15 Communication path 16 Ball groove 17 Communication path 18 Stem part 19 Clip 20 Inner ring (inner joint member)
22 spline hole 23 communication passage 24 outer peripheral surface 26 ball groove 28 communication passage 30 ball (torque transmission element)
40 Cage 42 Outer peripheral surface 44 Inner peripheral surface 46 Pocket 48 Communication passage

Claims (10)

  An outer ring in which ball grooves extending in the axial direction are formed at equal intervals in the circumferential direction on a cylindrical inner peripheral surface, and an inner ring in which ball grooves extending in the axial direction are formed at equal intervals in the circumferential direction on a spherical outer peripheral surface; The outer ring has a ball interposed between the ball groove of the outer ring and the ball groove of the inner ring, and a cage for holding the ball interposed between the inner peripheral surface of the outer ring and the outer peripheral surface of the inner ring. In a double offset type constant velocity universal joint that allows not only angular displacement but also axial displacement between the inner ring and the inner ring, grease and air can move between the inner side of the outer ring and the opening side during the axial displacement. Double offset type constant velocity universal joint with a connecting passage to allow.   The double offset type constant velocity universal joint according to claim 1, wherein the communication passage is provided in a ball groove bottom.   3. The double offset constant velocity universal joint according to claim 2, wherein the ball groove is a ball groove of an outer ring, a ball groove of an inner ring, or both ball grooves.   4. The double offset constant velocity universal joint according to claim 1, wherein the communication passage is provided on an inner peripheral surface of an outer ring.   The double offset type constant velocity universal joint according to any one of claims 1 to 4, wherein the communication passage is provided on an outer peripheral surface of the inner ring.   The double offset constant velocity universal joint according to any one of claims 1 to 5, wherein the communication passage is provided on an outer peripheral surface or an inner peripheral surface of the cage.   The double offset type constant velocity universal joint according to any one of claims 1 to 6, wherein the communication passage is provided by machining.   The double offset constant velocity universal joint according to any one of claims 1 to 6, wherein the communication passage is provided by plastic working.   The double offset type constant velocity universal joint according to any one of claims 1 to 8, wherein a ball groove of the outer ring or a ball groove of the inner ring or both are cold forged.   The double offset constant velocity universal joint according to any one of claims 1 to 8, wherein an inner peripheral surface of the outer ring is forged.

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