JP5241221B2 - Tripod type constant velocity universal joint - Google Patents

Description

The present invention relates to a tripod type constant velocity universal joint having a power transmission shaft for transmitting torque by spline coupling with an inner joint member .

  For example, a power transmission shaft (hereinafter simply referred to as a shaft) incorporated in a constant velocity universal joint shown in Patent Document 1 or Patent Document 2 has a male spline portion formed on the outer periphery, and an inner joint member (female). And a female spline portion formed on the inner periphery of the side member) so as to be able to transmit torque. A retaining ring groove is formed on the outer periphery of the shaft, and the retaining ring mounted in the retaining ring groove engages with the inner joint member, thereby preventing the shaft and the inner joint member from coming off.

Japanese Utility Model Publication No.4-116017 JP 2007-40425 A

  FIG. 5 shows a shaft 130 similar to the shaft shown in Patent Document 1. The shaft 130 has a male spline portion 134 formed on the outer periphery, and the male spline portion 134 is fitted with a female spline portion 126 formed on the inner periphery of the inner joint member 120 (shown by a one-dot chain line in the drawing). The male spline part 134 is formed up to the shaft end of the shaft 130, and a retaining ring 160 is mounted in a retaining ring groove 132 formed in the middle of the male spline part 134. When an axial force as indicated by an arrow in the drawing is applied to the shaft 130 of such a constant velocity universal joint from the outside, the retaining ring 160 attached to the retaining ring groove 132 is located on the shaft end side of the retaining ring groove 132. Drag is received from the inner wall 132a and the shaft end side end surface 120a of the inner joint member 120. At this time, since the shaft end side inner wall 132a of the retaining ring groove 132 and the shaft end side end surface 120a of the inner joint member 120 have a portion facing each other in the axial direction, the retaining ring 160 is sandwiched between these surfaces. Therefore, almost no bending moment is applied to the retaining ring 160, and the retaining ring 160 can be fixed in the retaining ring groove 132 even when the above axial force is applied. However, since the male spline part 134 is formed to the shaft end of the shaft 130, the outer diameter of the shaft 130 is constant until the shaft end, and the diameter of the retaining ring groove 132 is relatively large. . Accordingly, the diameter of the retaining ring 160 also needs to be increased, so that the outer diameter end of the retaining ring 160 may interfere with an accessory part (for example, the roller 140) of the inner joint member 120.

  FIG. 6 shows a shaft 230 similar to the shaft shown in Patent Document 2. The shaft 230 is provided with a cylindrical region 236 on the shaft end side of the male spline portion 234. The outer diameter of the cylindrical region 236 is slightly smaller than the valley 234a of the male spline portion 234, and a retaining ring groove 232 is formed in the cylindrical region 236. By reducing the diameter of the cylindrical region 236 in this way, the groove bottom of the retaining ring groove 232 is also reduced in diameter, and the retaining ring 260 can be reduced in diameter, so that the outer diameter end of the retaining ring 260 is connected to the inner joint member 120. The situation of interfering with the roller 140 or the like can be avoided. However, since the retaining ring groove 232 is formed in the cylindrical region 236 having a smaller diameter than the valley part 234a of the male spline part 234, the axial end side inner wall 232a of the retaining ring groove 232 and the axial end side end surface of the inner joint member 120 120a does not have a portion facing in the axial direction. Therefore, when an axial force as indicated by an arrow in the drawing is applied, a moment force acts on the retaining ring 260, and the retaining ring 160 may be detached from the retaining ring groove 232.

An object of the present invention is to provide a tripod type constant velocity universal joint capable of avoiding interference between a retaining ring and a roller and firmly fixing the retaining ring to a retaining ring groove.

To solve the above problems, the present invention is, on the outer circumference, a male spline portion, the male spline portion of the shaft end side formed retaining ring groove, and said snap ring land portions formed on the shaft end side of the groove And a female spline portion that fits with the male spline portion of the power transmission shaft is formed on the inner periphery, and has a leg shaft that protrudes from three circumferentially spaced intervals toward the outer diameter. An inner joint member, a retaining ring having a rectangular cross section that is attached in close contact with a groove bottom of a retaining ring groove of the power transmission shaft, and that prevents the inner joint member and the power transmission shaft from coming off, and the inner joint member Are arranged on the inner periphery, and are attached to the outer joint member in which three track grooves extending in the axial direction are formed at three locations at equal intervals in the circumferential direction, and to the respective leg shafts of the inner joint member so as to be rollable. Each of the outer joint members has a track groove. Is accommodated in the tripod type constant velocity universal joint and a roller for transmitting torque between said outer joint member and the inner joint member, the outer diameter of the lands is than valleys of the male spline portion outer diameter, and said located on the inner diameter side than the crests of the male spline section, partially facing the shaft end side inner wall of the retaining ring groove at an axial end side end face and the axial direction of the inner joint member, The groove bottom of the retaining ring groove is located on the inner diameter side of the valley of the male spline part, and the outer diameter of the hill part is 107% or more and 111% or less with respect to the diameter of the groove bottom of the retaining ring groove. A tripod type constant velocity universal joint is provided .

Thus, in the tripod type constant velocity universal joint shaft of the present invention, the outer diameter of the hill portion formed on the shaft end side of the retaining ring groove is set to the outer diameter side of the valley portion of the male spline portion. As a result, the inner wall on the shaft end side of the retaining ring groove and the end surface on the shaft end side of the female member can be partially opposed in the axial direction, so that almost no moment force is applied to the retaining ring even when axial force is applied. The retaining ring can be firmly fixed to the retaining ring groove. Moreover, the shaft of the tripod type constant velocity universal joint of this invention makes the outer diameter of the said hill part the inner diameter side rather than the peak part of a male spline part. As a result, the hill portion can be reduced in diameter compared to the conventional product of FIG. 5 in which the male spline portion is formed up to the shaft end, and the retaining ring groove bottom has a smaller diameter than the conventional product shown in FIG. Therefore, the outer diameter of the retaining ring mounted in the retaining ring groove is reduced, and the possibility of interference between the retaining ring and the roller can be reduced.

  If the retaining ring groove depth is too deep, it will be difficult to attach the retaining ring, so the outer diameter of the hill portion on the shaft end side of the retaining ring groove will be smaller than the diameter of the groove bottom of the retaining ring groove. It is preferable to set it to 111% or less. On the other hand, if the depth of the retaining ring groove is too shallow, the retaining force of the retaining ring may be insufficient. Therefore, the outer diameter of the hill is set to 107% or more with respect to the diameter of the retaining ring groove bottom. It is preferable.

Thus, since the outer diameter of the hill portion on the shaft end side of the retaining ring groove is larger than the valley portion of the male spline portion, the shaft of the tripod type constant velocity universal joint of the present invention has a cylindrical shape. If formed into a shape, when the inner joint member is assembled from the shaft end side of the shaft, there is a possibility that the peak portion of the female spline portion provided on the inner periphery of the inner joint member interferes with the cylindrical hill portion. In order to avoid such a situation, it is necessary to set the peak portion of the female spline portion so that it is positioned on the outer diameter side of the outer diameter of the cylindrical hill portion of the shaft. The diameter difference between the crest and trough is reduced, and the coupling force with the male spline is weakened. In view of this, be formed by extending the valleys of the male spline portion to the shaft end, when incorporating the inner joint member from the axial end of the shaft, the inner joint valleys of the male spline portion formed to the shaft end Since both can be assembled while fitting the female spline part on the inner circumference of the member , it is possible to avoid the situation where the female spline part interferes with the hill part of the shaft without increasing the diameter of the female spline part. it can.

As described above, according to the tripod type constant velocity universal joint of the present invention , in the power transmission shaft in which the male spline portion is formed on the opposite shaft end side of the retaining ring groove, the interference between the retaining ring and the roller is avoided. The retaining ring can be firmly fixed to the retaining ring groove.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 shows a constant velocity universal joint 1 in which a shaft 30 according to the present invention is incorporated. This constant velocity universal joint 1 is a sliding type constant velocity universal joint, more specifically, a tripod type constant velocity universal joint, and an outer joint member 10 and an inner side as a female side member accommodated in the inner periphery of the outer joint member 10. The joint member 20 is mainly provided with a shaft 30 fixed to the inner joint member 20 and a roller 40 as a torque transmission member.

  The outer joint member 10 is formed in a bottomed cylindrical cup shape, and a plurality of track grooves 14 extending in the axial direction are formed at three locations on the inner peripheral surface 12 at equal intervals in the circumferential direction. The inner joint member 20 has leg shafts 22 projecting toward the outer diameter at three positions at equal intervals in the circumferential direction, and a roller 40 is attached to each leg shaft 22. A plurality of rollers 50 are arranged between the outer peripheral surface of the leg shaft 22 and the inner peripheral surface of the roller 40, so that the roller 40 can roll with respect to the leg shaft 22. Each roller 40 is accommodated in the track groove 14 of the outer joint member 10, whereby the outer joint member 10 and the inner joint member 20 are connected so as to transmit torque. An annular stopper 28 is attached to the end of the leg shaft 22, thereby preventing the leg shaft 22, the roller 40 and the roller 50 from coming off.

  A shaft 30 is inserted into the inner periphery of the inner joint member 20, and a female spline portion 26 formed on the inner peripheral surface 24 of the inner joint member 20 and a male spline portion 34 formed on the outer peripheral surface of the shaft 30 are fitted. Thus, both members are coupled so that torque can be transmitted. A retaining ring groove 32 is formed near the shaft end of the shaft 30, and a retaining ring 60 attached to the retaining ring groove 32 prevents the shaft 30 and the inner joint member 20 from coming off. The retaining ring 60 is formed of an elastic material such as metal in a ring shape having a rectangular cross section, and can be enlarged or reduced in diameter by cutting out a part in the circumferential direction.

  FIG. 2 shows an enlarged view of the vicinity of the shaft end of the shaft 30. The shaft 30 has a male spline part 34, a small diameter part 38 provided on the shaft end side of the male spline part 34, and a retaining ring groove 32 provided in the small diameter part 38 on the outer periphery. It is formed by manufacturing process. The retaining ring groove 32 is formed in a U-shaped cross section on the entire circumference in the vicinity of the shaft end of the shaft 30. The trough 34b of the male spline portion 34 is formed to extend to the shaft end, that is, the trough 34b is also formed in the small diameter portion 38. The outer diameter of the small diameter portion 38 is located on the outer diameter side of the trough portion 34 b of the male spline portion 34 and on the inner diameter side of the peak portion 34 a of the male spline portion 34. Of the small diameter portion 38, a hill portion 36 is formed by a portion on the shaft end side of the retaining ring groove 32.

Thus, since the outer diameter of the hill portion 36 (small diameter portion 38) is on the outer diameter side of the valley portion 34b of the male spline portion 34, the shaft end side inner wall 32a of the retaining ring groove 32 and the inner joint member 20 are provided. Can be partially opposed to the axial end side surface 20a in the axial direction of the shaft 30. As a result, when an axial force is applied to the shaft 30, the retaining ring 60 is sandwiched between the axially opposed portions of these surfaces, so that almost no moment force acts on the retaining ring 60, and the retaining ring 60 is attached to the retaining ring 60. The groove 32 can be firmly fixed. Further, since the outer diameter of the hill portion 36 is closer to the inner diameter side than the peak portion 34a of the male spline portion 34, the shaft end portion is compared with the conventional product (see FIG. 6) in which the male spline portion is formed up to the shaft end. Since the outer diameter is reduced, the retaining ring 60 can be reduced in diameter, and the situation where the outer diameter end of the retaining ring 60 interferes with another member (for example, the roller 40) can be avoided. Further, if the retaining ring groove 32 is too deep, it is difficult to mount the retaining ring 60, and if the groove depth is too shallow, the retaining ring 60 may have insufficient fixing force. D ₂ is set to 107% or more and 111% or less of the diameter D ₁ of the groove bottom of the retaining ring groove 32 (1.07D ₁ ≦ D ₂ ≦ 1.11D ₁ ).

  Further, when the valley portion 34b of the male spline portion 34 is formed to the shaft end, when the inner joint member 20 is assembled from the shaft end side of the shaft 30, the male spline portion 34 of the shaft 30 and the female spline of the inner joint member 20 are assembled. Since the portion 26 can be incorporated while being fitted, a situation where the female spline portion 26 of the inner joint member 20 interferes with the hill portion 36 of the shaft 30 can be avoided.

  In order to prove the usefulness of the present invention, the following tests were conducted. First, a shaft A as a product according to the present invention shown in FIG. 2 and a shaft B as a comparative product according to a conventional example shown in FIG. 6 were prepared using a C-shaped retaining ring having a nominal diameter 26 of JIS B2804. . The outer diameter of the hill portion of the shaft A is set to 109% with respect to the groove bottom diameter of the retaining ring groove, and the outer diameter of the hill portion (male spline portion) of the shaft B is set to 104% with respect to the groove bottom diameter of the retaining ring groove. Set. The ratio 104% of the shaft B matches the ratio calculated from the shaft diameter d1 and the groove diameter d2 of JIS B2804. The axial force was repeatedly applied to these shafts by the method shown in FIG. 3, and the number of times until the snap ring was broken was compared. Specifically, an inner joint member 70 as a female side member having a female spline portion 72 on the inner periphery is fitted to a male spline portion 82 on the outer periphery of the shaft 80, and a retaining ring 90 is mounted in a retaining ring groove of the shaft. To do. The end surface of the cylindrical jig G is brought into contact with the end surface 74 on the side opposite to the shaft end of the inner joint member 70 of the integrated product to restrain the inner joint member 70 in the axial direction. The number of times until the retaining ring 90 was damaged was recorded by repeatedly applying an axial force as shown in FIG.

A graph of the above test results is shown in FIG. In this graph, the horizontal axis represents the number of times until the retaining ring breaks, and the vertical axis represents the magnitude of the applied axial force as a ratio when the smallest load is 1. From this graph, the product A of the present invention is about twice as much in axial force as the comparison product B (comparing the axial force when the number of loads is 10 ³ times), and about 10 times the number of loads until breakage. Strength improvement was confirmed (comparison of the number of loadings when the axial force is 1).

It is sectional drawing of a tripod type constant velocity universal joint. It is the partial side view which expanded the axial end vicinity of the shaft. It is sectional drawing which shows the method of a breakage test of a retaining ring. It is a graph which shows the result of a breakage test of a retaining ring. It is sectional drawing of the conventional shaft. It is sectional drawing of the conventional shaft.

1 tripod type constant velocity universal joint 10 outer joint member 20 inner joint member (female side member)
30 Shaft 32 Retaining ring groove 34 Male spline part 36 Hill part 38 Small diameter part 40 Roller 60 Retaining ring

Claims (2)

On the outer circumference, a male spline portion, the stop is formed on the shaft end side of the male spline section ring groove, and a power transmission shaft and a hill portion that is formed on the shaft end side of the snap ring groove, the power transmission An inner joint member having a female spline portion that fits with a male spline portion of the shaft is formed on the inner periphery, and has a leg shaft that protrudes from three circumferentially spaced intervals toward the outer diameter, and a stop of the power transmission shaft Mounted in close contact with the groove bottom of the annular groove, a retaining ring having a rectangular cross section that prevents the inner joint member and the power transmission shaft from coming off, and the inner joint member are arranged on the inner periphery, in the circumferential direction, etc. An outer joint member in which three track grooves extending in the axial direction are formed at three intervals and attached to each leg shaft of the inner joint member so as to be able to roll and accommodated in the track grooves of the outer joint member, respectively. The inner joint member and the In the tripod type constant velocity universal joint and a roller for transmitting torque between the side joint member,
The outer diameter of the lands is outer diameter side than the valleys of the male spline portion, and wherein located on the inner diameter side than the crests of the male spline portion, the inner shaft end side inner wall of the retaining ring groove It is partially opposed to the shaft end side end face of the joint member in the axial direction, the groove bottom of the retaining ring groove is located on the inner diameter side of the valley portion of the male spline portion, and the outer diameter of the hill portion is Tripod type constant velocity universal joint that is 107% or more and 111% or less with respect to the diameter of the groove bottom of the annular groove . The tripod type constant velocity universal joint according to claim 1, wherein a trough portion of the male spline portion is formed to extend to a shaft end.

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