JP2009185872A - Shaft connection structure for constant velocity joint - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a shaft connection structure for a constant velocity joint, capable of surely preventing the come-off of a shaft from an inner race. <P>SOLUTION: An annular groove 27 is formed in a driving shaft 12 along the circumferential direction and an externally toothed spline 24 is formed extending from the front end to the base end side beyond the annular groove 27, and a snap ring 28 with its diameter elastically shrinkable is arranged in the annular groove 27. The driving shaft 12 is pressed into a through-hole 20 of the inner race 13 in the condition that the diameter of the snap ring 28 is shrunk, and the driving shaft 12 and the inner race 13 are connected to each other via the restored snap ring 28 with their relative movement restricted in the direction of a rotational axis L1. A front end side spline 41 on the front end side of the externally toothed spline 24 beyond the annular groove 27 is inserted into an internally toothed spline 26 formed on the inner race 13 in a non-pressed-in condition. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a connecting structure of a shaft connected to an inner race of a constant velocity joint.

  2. Description of the Related Art Conventionally, there is a constant velocity joint that connects two axes on the input side and the output side, and can transmit torque at a constant speed even when these two axes are not coaxial. As such a constant velocity joint, an inner race formed with a first ball groove extending in the rotation axis direction, and a bottomed hemispherical outer race formed with a plurality of second ball grooves respectively corresponding to the first ball grooves, There is a ball type constant velocity joint provided with a ball member interposed between the first and second ball grooves (see, for example, Patent Document 1).

In the constant velocity joint described in Patent Document 1, an annular groove extending in the circumferential direction is formed in the shaft, and an external spline extending from the distal end to the proximal end side of the annular groove is formed. The inner race spline is formed so as to be connected to the inner race so as not to rotate relative to the inner race. In this shaft connection structure, a retaining member (snap ring) that can be elastically reduced in diameter is arranged in the annular groove, and the shaft is press-fitted into the inner race with the snap ring being reduced in diameter, and the snap ring is in the inner race. It is designed to restore where it passes. And, since the restored snap ring is interposed between the external spline and the internal spline, the relative movement in the rotation axis direction between the shaft and the inner race is restricted, and the shaft is prevented from coming out of the inner race. Yes. In general, in such a constant velocity joint shaft coupling structure, the shaft is press-fitted into the inner race, thereby eliminating the gap between the two splines and suppressing the rattling in the circumferential direction to generate noise. Is preventing.
JP 2007-24269 A

  Incidentally, the tip of the shaft is not subjected to heat treatment (quenching or the like) in order to prevent burning cracks, and flash may occur when the shaft is press-fitted into the inner race. If the burr enters the annular groove, the snap ring cannot be restored from the reduced diameter, and the shaft may not be prevented from coming off the inner race. Such problems are not limited to the ball type constant velocity joints, and even in other constant velocity joints, the shaft is press-fitted into the inner race with the retaining member reduced in diameter in the annular groove. The same occurs when connecting the shaft and the inner race.

  The present invention has been made to solve the above problems, and an object of the present invention is to provide a shaft connection structure of a constant velocity joint that can surely prevent the shaft from coming off the inner race.

  In order to achieve the above object, according to the first aspect of the present invention, there is provided an axial shape in which an annular groove is formed along the circumferential direction and an external spline extending from the distal end to the proximal side of the annular groove is formed. And a retaining member disposed in the annular groove and capable of being elastically contracted, and the retaining member is contracted to an inner race of a constant velocity joint having a through hole through which the shaft is inserted. A shaft coupling structure of a constant velocity joint in which the shaft is press-fitted in a state of having a diameter and relative movement in the rotation axis direction between the shaft and the inner race is restricted by the restored retaining member, and the external teeth The tip spline on the tip side of the annular groove in the spline needs to be formed so as to be inserted into the internal spline formed in the inner race in a non-press-fit state. To.

  According to the above configuration, since the tip side spline is inserted into the internal spline in a non-pressed state, no flash is generated from the tip side spline when the shaft is assembled. For this reason, it is prevented that the retaining member cannot be restored from the reduced diameter due to the flash generated in the conventional manner, and the retaining member is reliably restored. And since the retaining member is interposed between the internal spline and the tip spline, it is possible to reliably prevent the shaft from coming out of the inner race.

  According to a second aspect of the present invention, in the shaft connection structure of the constant velocity joint according to the first aspect, the maximum overball diameter of the distal end side spline is set to a base end side proximal to the annular groove in the external spline. The gist is that it is smaller than the maximum overball diameter of the end spline.

  According to the above configuration, the maximum overball diameter of the distal end side spline is smaller than the maximum overball diameter of the proximal side spline on the proximal side relative to the annular groove in the external tooth spline. In other words, by setting the overball diameter so that the tooth thickness of the tip spline is smaller than the tooth gap width of the inner spline, the tip spline is inserted into the inner spline in a non-press-fit state. . Therefore, it is possible to insert the tip side spline into the internal spline in a non-pressed state without changing the number of tip side splines. Therefore, compared with the case where every other external spline is missing, for example, it is not necessary to reduce the contact area of the retaining member with the external spline, and the retaining member is caused by the stress acting on the retaining member. Can prevent the shaft from coming out of the inner race more reliably.

  According to a third aspect of the present invention, in the shaft connection structure of the constant velocity joint according to the first or second aspect, the constant velocity joint includes a plurality of first balls parallel to the rotation axis on the outer spherical surface of the inner race. A bottomed outer race in which a plurality of second ball grooves respectively corresponding to the first ball grooves are formed on an inner spherical surface, and interposed between the first ball grooves and the second ball grooves. And the inner race and the ball are incorporated in the outer race, and the shaft is a ball-type constant velocity joint that is press-fitted into the inner race.

  With a fixed ball-type constant velocity joint that press-fits the shaft into the inner race with the inner race and ball assembled in the bottomed outer race, the flash is removed after assembly even if a flash occurs from the tip side spline. In some cases, the retaining member cannot be restored. In this respect, according to the above-described configuration, since no flash is generated by the assembly of the shaft, the shaft can be reliably prevented from coming out of the inner race even with a fixed ball type constant velocity joint.

  ADVANTAGE OF THE INVENTION According to this invention, the shaft connection structure of the constant velocity joint which can prevent reliably that a shaft remove | deviates from an inner race can be provided.

Hereinafter, an embodiment in which the present invention is embodied in a fixed ball type constant velocity joint will be described with reference to the drawings.
As shown in FIG. 1, the constant velocity joint 11 includes an inner race 13 connected to the drive shaft 12 and an outer race 15 formed integrally with the driven shaft 14. In addition, the constant velocity joint 11 is interposed between the inner race 13 and the outer race 15, and a plurality of (six in this embodiment) balls 16 that transmit torque therebetween, and the balls 16 And a cage 17 for holding the In the present embodiment, the drive shaft 12 corresponds to a shaft.

  The inner race 13 is formed in a substantially annular shape having a through hole 20 through which the drive shaft 12 is inserted, and a plurality of outer races 21 formed in a convex spherical shape extend along the rotation axis L <b> 1 of the drive shaft 12. First ball grooves 22 (the same number as the balls 16) are formed at equal intervals in the circumferential direction. Further, the through-hole 20 is formed in a cylindrical shape centered on the axis of the inner race 13, and the inner race 13 and the drive shaft 12 cannot be relatively rotated by the spline fitting of the end of the drive shaft 12. It is connected.

  As shown in FIG. 2, external splines 24 are formed on the outer peripheral surface 23 on the distal end side (the right side in FIGS. 1 and 2) of the drive shaft 12, and the inner peripheral surface of the through hole 20 of the inner race 13. An internal tooth spline 26 corresponding to the external tooth spline 24 is formed. An annular groove 27 extending in the circumferential direction is formed on the distal end side of the portion of the drive shaft 12 where the external spline 24 is formed, and a snap ring 28 as a retaining member is disposed in the annular groove 27. Has been. The snap ring 28 is formed in a substantially C shape that can be elastically reduced in diameter, and a part of the outer peripheral edge of the snap ring 28 protrudes beyond the tooth tip of the external tooth spline 24 when the diameter is not reduced. . The annular groove 27 may pass through the small diameter of the internal spline 26 by reducing the diameter of the snap ring 28 when the external spline 24 of the drive shaft 12 and the internal spline 26 of the inner race 13 are fitted. The reduced diameter snap ring 28 is formed to a depth that does not interfere with the internal spline 26 so that it can be formed.

  Further, as shown in FIG. 1, the outer race 15 is formed in a bottomed hemispherical shape (cup shape), and the inner spherical surface 29 formed in a concave spherical shape is paired with the first ball groove 22 respectively. A plurality of (same number as the balls 16) second ball grooves 30 are formed along the rotation axis L <b> 2 of the driven shaft 14. In addition, the driven shaft 14 is integrally formed at the bottom of the outer race 15 so that the outer race 15 and the driven shaft 14 are connected so as not to rotate relative to each other.

  The cage 17 is formed in a substantially annular shape and is disposed between the outer spherical surface 21 of the inner race 13 and the inner spherical surface 29 of the outer race 15. In the cage 17, the same number of ball holding windows 31 as the balls 16 are formed at equal intervals in the circumferential direction. Each ball 16 is interposed between the paired first ball groove 22 and second ball groove 30 while being accommodated in the ball holding window 31 of the cage 17.

  In the constant velocity joint 11 configured as described above, the drive shaft 12 connected to the inner race 13 moves relative to the outer race 15 through the movement of the balls 16 along the first and second ball grooves 22 and 30. It can swing freely (tilt). FIG. 1 shows a state in which the tilt angle (joint angle) is 0 °. On the other hand, since the displacement of the ball 16 in the circumferential direction is restrained by the side walls of the first and second ball grooves 22 and 30, the axis of the outer race 15 (driven shaft 14) and the inner race 13 (drive shaft 12). Relative rotation around is restricted. By such a constant velocity joint 11, the drive shaft 12 and the driven shaft 14 are coupled so as to be capable of relative tilting while maintaining constant rotation transmission.

Next, the shaft connection structure of the constant velocity joint 11 will be described in detail.
In the present embodiment, the types of splines of the external splines 24 and the internal splines 26 will be described as involute splines.

  A tip side spline 41 on the tip side of the annular groove 27 in the external tooth spline 24 is inserted into the internal tooth spline 26 in a non-press-fit state. Further, the base end side spline 42 on the base end side (left side in FIGS. 1 and 2) with respect to the annular groove 27 in the external tooth spline 24 is press-fitted into the internal tooth spline 26 with a predetermined press-fitting allowance. It has become.

  In the present embodiment, as shown in FIGS. 3A and 3B, the drive shaft 12 is formed such that the maximum overball diameter of the distal end side spline 41 is smaller than the maximum overball diameter of the proximal end side spline 42. . Here, the overball diameter (hereinafter referred to as OBD (Over Ball Diameter)) refers to each of the tooth gaps (in the case of even-numbered teeth) on the diameter of the external spline 24 or on the diameter. Between the outer diameters of the two balls when one ball of appropriate diameter is inserted into each of the tooth gaps (in the case of odd teeth) where one of them is biased by π / (number of teeth) Dimension. That is, as shown in FIG. 4, the front-side spline 41 has an internal tooth spline in a non-press-fit state by setting the OBD so that the tooth thickness S1 is smaller than the tooth gap width E of the internal spline 26. 26 to be inserted. In addition, as shown in FIG. 5, the proximal spline 42 has an inner diameter set by the OBD so that the tooth thickness S2 (see FIG. 6) is larger than the tooth gap width E of the internal spline 26. The tooth spline 26 is press-fitted with a predetermined press-fitting allowance. Here, the tooth thickness and the tooth gap width of each spline are measured at the position of the reference pitch circle C. In the present embodiment, each tooth tip 41a, 42a (large diameter) in the distal end side spline 41 and proximal end side spline 42 and each tooth bottom 26b (large diameter) in the internal tooth spline 26 are opposed to each other in the radial direction. Setting is made so that a positive gap is provided in a radially opposing portion between each tooth tip 26a (small diameter) in the internal tooth spline 26 and each tooth bottom 41b, 42b (small diameter) in the distal end side spline 41 and the proximal end side spline 42. Has been. A predetermined lead angle θ is set for the external tooth spline 24 with respect to the rotation axis L1.

  Accordingly, as shown in FIG. 6, the external spline 24 is formed such that the tooth thickness S1 of the distal spline 41 is smaller than the tooth gap width E of the internal spline 26, and the tooth thickness S2 of the proximal spline 42 is It is formed larger than the tooth gap width E of the internal tooth spline 26. In FIG. 6, for the convenience of explanation, the external splines 24 and the internal splines 26 are hatched.

  In the constant velocity joint 11, the drive shaft 12 is press-fitted into the inner race 13 in a state where the inner race 13 and the ball 16 are incorporated in the outer race 15. The drive shaft 12 is press-fitted into the inner race 13 with the snap ring 28 reduced in diameter in the annular groove 27. At this time, as shown in FIG. 4, since the front end side spline 41 is inserted into the internal spline 26 in a non-press-fit state, no flash is generated from the front end side spline 41. Therefore, it is prevented that the snap ring cannot be restored from the reduced diameter due to the occurrence of flash as in the conventional case, and the snap ring 28 is restored when it passes through the inner race 13. Then, the snap ring 28 is interposed between the internal spline 26 and the tip side spline 41, so that the relative movement of the drive shaft 12 and the inner race 13 in the direction of the rotation axis L1 is restricted, and the drive shaft 12 is moved to the inner race. 13 can be prevented from coming off.

As described above, according to the present embodiment, the following operations and effects are achieved.
(1) An annular groove 27 extending in the circumferential direction is formed on the drive shaft 12 and an external spline 24 extending from the distal end to the proximal side of the annular groove 27 is formed. A ring 28 was provided. The drive shaft 12 is press-fitted into the through hole 20 of the inner race 13 with the snap ring 28 having a reduced diameter, and the restored snap ring 28 restricts relative movement of the drive shaft 12 and the inner race 13 in the direction of the rotation axis L1. Connected. Then, the tip spline 41 on the tip side of the annular groove 27 in the external tooth spline 24 is formed so as to be inserted into the inner tooth spline 26 formed in the inner race 13 in a non-press-fit state. Therefore, since the tip side spline 41 is inserted into the internal spline 26 in a non-press-fit state, no flash is generated from the tip side spline 41 when the drive shaft 12 is assembled. For this reason, it is prevented that the snap ring cannot be restored from the reduced diameter due to the flash generated as in the conventional case, and the snap ring 28 is reliably restored. The snap ring 28 is interposed between the internal spline 26 and the tip spline 41, so that the drive shaft 12 can be reliably prevented from coming off the inner race 13.

  (2) The maximum OBD of the distal end side spline 41 is made smaller than the maximum OBD of the proximal end side spline 42. Therefore, it is possible to insert the tip side spline 41 into the internal spline 26 in a non-press-fit state without changing the number of tip side splines 41. Therefore, for example, compared with a case where every other tip side spline is missing, it is not necessary to reduce the contact area of the snap ring 28 with the tip side spline 41, and the snap ring 28 is affected by the stress acting on the snap ring 28. It is possible to prevent the drive shaft 12 from coming out of the inner race 13 more reliably by preventing the deformation of the 28.

  (3) Since the predetermined lead angle θ is set to the external tooth spline 24, the drive shaft 12 and the inner race 13 can be reduced even if the press-fitting allowance between the external tooth spline 24 (base end side spline 42) and the internal tooth spline 26 is reduced. It is possible to increase the fixing force (prevention force) between the two. Therefore, as compared with the case where the lead angle θ is not set, a large fixing force can be obtained even if the press-fit load of the drive shaft 12 is reduced, and the assembling property can be improved.

  (4) The constant velocity joint 11 is a fixed ball type constant velocity joint in which the drive shaft 12 is press-fitted into the inner race 13 in a state where the inner race 13 and the ball 16 are incorporated in the bottomed outer race 15. Configured. Therefore, even if the flash is generated from the tip side spline by the assembly and the snap ring 28 cannot be restored by the flash, the flash cannot be removed after the assembly. In this regard, according to the present embodiment, since no flash is generated by the assembly of the drive shaft 12, it is possible to reliably prevent the drive shaft 12 from coming off the inner race 13.

In addition, you may implement this embodiment in the following aspects.
In the present embodiment, the OBD of the external spline 24 is continuously changed from the base end side toward the front end side. However, the present invention is not limited thereto, and the front end side spline 41 may be inserted in a non-press-fit state. For example, the OBD of the tip side spline 41 may be constant.

  In the present embodiment, the OBD of the distal end side spline 41 is made smaller than the OBD of the proximal end side spline 42. However, the present invention is not limited to this, and the distal side spline 41 may be inserted in a non-press-fit state. Every other 41 spline teeth may be missing.

  In the present embodiment, the predetermined lead angle θ is set for the external tooth spline 24, but the present invention is not limited thereto, and the predetermined lead angle θ may be set for the internal tooth spline 26. Further, the lead angle is not set to the external spline 24 and the internal spline 26, the external spline 24 and the internal spline 26 are formed in parallel to the rotation axis L1, and the base end side spline 42 has a predetermined press-fitting allowance. And may be press-fitted into the internal spline 26.

  In the present embodiment, the tooth thickness S2 of the base end side spline 42 is made to be larger than the tooth gap width E of the internal spline 26, but the present invention is not limited thereto, and the tooth thickness of the base end side spline 42 is not limited thereto. May be set to be equal to or smaller than the tooth gap width of the internal spline 26 and may be press-fitted into the internal spline 26 by setting only the lead angle.

  In the present embodiment, the snap ring 28 is restored by the annular groove 27 projecting toward the tip side of the inner race 13. However, the present invention is not limited to this, and a groove for restoring the snap ring 28 having a reduced diameter is provided on the inner peripheral surface of the through hole 20 of the inner race 13, and the snap ring is restored in the groove so that the drive shaft 12 is You may make it prevent coming out of the inner race 13.

In the present embodiment, the splines of the external splines 24 and the internal splines 26 are involute splines, but other spline shapes may be applied.
In this embodiment, the constant velocity joint 11 is configured as a fixed ball-type constant velocity joint. However, the present invention is not limited to this, and the shaft is inserted into the inner race with the retaining member reduced in diameter in the annular groove. If so, the present invention may be applied to a sliding ball type constant velocity joint, a tripod joint, or the like.

Sectional drawing which shows schematic structure of a constant velocity joint. The enlarged cross-sectional view of an inner race and a drive shaft. (A) Enlarged view of drive shaft, (b) Waveform diagram showing OBD of external spline. The partial cross section figure at the time of a front end side spline being inserted in an inner race. The partial cross section at the time of a base end side spline being press-fitted in an inner race. The schematic diagram which shows schematic structure of an external-tooth spline and an internal-tooth spline.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 ... Constant velocity joint, 12 ... Drive shaft, 13 ... Inner race, 15 ... Outer race, 16 ... Ball, 20 ... Through-hole, 21 ... Outer spherical surface, 22 ... First ball groove, 24 ... External spline, 26 ... Inner Tooth spline, 27 ... annular groove, 29 ... inner spherical surface, 30 ... second ball groove, 41 ... distal end side spline, 42 ... proximal end side spline, L1, L2 ... rotation axis.

Claims (3)

An axial groove formed along the circumferential direction and formed with an external spline extending from the distal end to the base end side of the annular groove, and an elastic shaft that is disposed in the annular groove and can be elastically reduced in diameter. A retaining member,
The shaft is press-fitted into the inner race of a constant velocity joint in which a through-hole through which the shaft is inserted is formed with the diameter of the retaining member being reduced, and the shaft and the inner race are restored by the restored retaining member. And a constant velocity joint shaft coupling structure in which relative movement in the rotational axis direction is restricted,
The constant-velocity joint is characterized in that a tip-side spline on the tip side of the annular groove in the external tooth spline is formed so as to be inserted into the inner-tooth spline formed in the inner race in a non-pressed state. Shaft connection structure.   2. The constant velocity according to claim 1, wherein a maximum overball diameter of the distal-side spline is smaller than a maximum overball diameter of a proximal-side spline that is proximal to the annular groove in the external tooth spline. Joint shaft connection structure. The constant velocity joint is
A plurality of first ball grooves parallel to the rotation axis are formed on the outer spherical surface of the inner race,
A bottomed outer race in which a plurality of second ball grooves respectively corresponding to the first ball grooves are formed on an inner spherical surface;
A ball interposed between the first ball groove and the second ball groove;
3. The constant velocity joint according to claim 1, wherein the shaft is a ball-type constant velocity joint that is press-fitted into the inner race in a state where the inner race and the ball are incorporated in the outer race. Shaft connection structure.

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