JP2008232292A - Constant velocity universal joint - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a constant velocity universal joint, which can be simplified in its machining process and reduced in weight by reducing the number of part items. <P>SOLUTION: The constant velocity universal joint comprises an external joint member and an internal joint member internally fitted to the external joint member through a torque transmitting member. The internal joint member is joined and integrated with a shaft 61 through a joint part 62 which is formed in a state where the internal joint member and the shaft 61 are partially butted or overlapped with each other. This joint further comprises a boot 64 having a major diameter part 64a to be installed to the external joint member and a minor diameter part 64b to be installed to the shaft 61 to close an opening part 63 on the shaft protruding side of the external joint member. The joint part 62 is covered with the boot 64 on the joint means. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

The present invention is used in power transmission systems of automobiles and various industrial machines, and particularly relates to a constant velocity universal joint for automobile propulsion shafts (propeller shafts) and drive shafts (drive shafts).

  The constant velocity universal joint for the propeller shaft includes a cross groove type (for example, Patent Document 1) and a tripod type. The cross groove type constant velocity universal joint shown in FIG. 5 includes an inner ring 3 as an inner joint member having outer peripheral surfaces 2 in which ball grooves 1 twisted in opposite directions with respect to an axis are alternately formed in the circumferential direction, An outer ring 6 as an outer joint member having an inner peripheral surface 5 in which ball grooves 4 twisted in directions opposite to each other in the circumferential direction are alternately formed, and an inner ring 3 twisted in directions opposite to each other in relation to the axis. The torque transmitting ball 7 is circularly interposed between the outer peripheral surface 2 of the inner ring 3 and the inner peripheral surface 5 of the outer ring 6 and the torque transmitting ball 7 incorporated at the intersection of the ball groove 1 and the ball groove 4 of the outer ring 6. And a cage 8 held at a predetermined interval in the circumferential direction.

  The inner ring 3 is spline-fitted by inserting the spline part 11 of the shaft part 10a of the stub shaft 10 into the center hole (inner diameter hole) so that torque can be transmitted between the two by the spline fitting. For this reason, a spline portion 13 is formed on the inner diameter surface 12 of the inner ring 3. The stub shaft 10 includes the shaft portion 10a and a mouse portion 10b connected to the shaft portion 10a. Further, a circumferential groove 15 is formed in the spline portion 11 of the shaft portion 10 a of the shaft 10, and a retaining ring 16 for retaining is attached to the circumferential groove 15.

  The opening on the shaft protruding side of the outer ring 6 is closed by a boot 17. The boot 17 includes a boot main body 18 made of an elastic member such as rubber, and a metal reinforcing member 19 embedded in the boot main body 18. The boot body 18 includes a large-diameter portion 18a, a small-diameter portion 18b, an intermediate cylindrical portion 18c extending from the large-diameter portion 18a to the side opposite to the outer ring, and a curved portion 18d connecting the intermediate cylindrical portion 18c and the small-diameter portion 18b. Become. The reinforcing member 19 is embedded in a part of the intermediate cylindrical portion 18c and the large diameter portion 18a of the boot body 18. The large diameter portion 18 a is externally fitted to the outer ring 6 and fastened by the boot band 20, and the small diameter portion 18 b is externally fitted to the shaft portion 10 a of the shaft 10 and fastened by the boot band 20.

  An intermediate shaft 21 is coupled to the mouth portion 10b of the stub shaft 10. In this case, the opening end surface of the mouse part 10b and the opening end surface of the intermediate shaft 21 are integrally connected by a joining means such as friction welding. Here, the friction welding means that two base materials are brought into contact with each other and relatively rotated, and a frictional heat is generated on the contact surface by adding a thrust. This is a method of softening the abutting surface and its vicinity by the heat and stopping the relative motion when the pressure temperature is reached, further increasing the pressure thrust and joining the two base materials.

  The constant velocity universal joint shown in FIG. 7 has an outer joint member in which three track grooves 32 are formed in the axial direction on the inner peripheral surface 31 and axial roller guide surfaces 33 are provided on both sides of each track groove 32. 34, a tripod member 37 in which three leg shafts 36 projecting in the radial direction on the outer peripheral surface 35 are formed at equal intervals in the circumferential direction, and each leg shaft 36 of the tripod member 37 are rotatably attached to the track groove. And a roller 38 that is inserted into the outer joint member 32 and transmits torque between the outer joint member 34 and the tripod member 37.

  The tripod member 37 is spline-fitted by inserting the spline part 11 of the shaft part 10a of the stub shaft 10 into the center hole (inner diameter hole) so that torque can be transmitted between the two by the spline fitting. For this reason, the spline portion 40 is formed on the inner diameter surface 39 of the tripod member 37. Further, a circumferential groove 41 is formed at the end of the shaft portion 10 a of the shaft 10, and a retaining ring 42 for retaining is attached to the circumferential groove 41.

The opening on the shaft protruding side of the outer joint member 34 is sealed with a sealing device 45. The sealing device 45 includes a boot adapter 46 attached to the outer joint member 34 and a boot 47 attached to the boot adapter 46. The boot adapter 46 includes a large-diameter portion 46a and an adapter main body portion 46b extending from the large-diameter portion 46a to the opposite outer joint member side. The boot 47 includes a large-diameter portion 47a, a small-diameter portion 47b, and a folded portion 47c that connects the small-diameter portion 47b and the large-diameter portion 47a. And the large diameter part 47a of the boot 47 is fixed to this boot adapter 46 by crimping the edge part of the adapter main-body part 46b. The small diameter portion 47 b of the boot 47 is externally fitted to the shaft portion 10 a of the shaft 10 and fastened by the boot band 48.
JP 2002-372067 A

  As described above, the constant velocity universal joint shown in FIG. 5 and the constant velocity universal joint shown in FIG. 7 are connected to the inner joint member and the shaft by spline coupling, and at the end of the shaft. It is necessary to provide a circumferential groove and fit a retaining ring in the circumferential groove. For this reason, the number of parts and the number of processing steps are large, and the assemblability is poor. That is, the one shown in FIGS. 5 and 7 requires a spline processing (spline broaching) of the inner ring, a groove processing for the retaining ring of the shaft, a spline press-fitting process, and a retaining ring assembling process.

  By the way, when a retaining ring is required, if the retaining ring is not attached, the shaft comes out from the inner joint member. For this reason, the presence or absence of retaining rings is an important item for quality confirmation. Therefore, in the assembled state (assembled state), as long as the retaining ring 42 is exposed from the inner joint member (in this case, the tripod member 37) as shown in FIG. As described above, in the appearance inspection of the retaining ring 16 disposed inside the inner joint member (inner ring) 3, it is difficult to confirm the presence or absence of the retaining ring, and a process for quality confirmation other than the appearance inspection is required. As a result, the productivity is inferior.

  Furthermore, in spline fitting like the constant velocity universal joint shown in FIG. 5 and FIG. 7, there is a possibility that backlash occurs in the circumferential direction. In order to suppress this play, the press-in design is usually performed in consideration of the twist angle of the spline. However, even if designed in this way, there may be a backlash due to the process capability of the press-fit load and the process capability of the spline accuracy. Further, play may occur due to wear of the spline portion due to a load during normal operation. The propeller shaft is used at high speed rotation, and it is desirable that the backlash in the circumferential and radial directions is smaller in order to suppress vibration. Moreover, in recent years, the need for weight reduction has increased, and it is necessary to respond.

  In view of the above-described problems, the present invention provides a constant velocity universal joint that can reduce the number of parts, simplify the machining process, and reduce the weight.

  A constant velocity universal joint according to the present invention is a constant velocity universal joint including an outer joint member and an inner joint member that is housed in the outer joint member via a torque transmission member, and includes the inner joint member and the shaft. The inner joint member and the shaft are joined and integrated through a joint portion formed in a state where parts of each other are butted or overlapped. Here, the joint integration means that the inner joint member and the shaft are joined together (by joining or overlapping), and a conventional retaining ring is used. It is an integration without connecting means.

  In the constant velocity universal joint of the present invention, since the shaft is joined and integrated with the inner joint member, it is not necessary to form a spline for shaft engagement on the inner joint member, and a retaining ring for retaining is not required. Moreover, there is no play in the circumferential direction.

  A boot having a large-diameter portion attached to the outer joint member and a small-diameter portion attached to the shaft to block the opening of the outer joint member on the shaft protruding side is provided. In this boot, the inner joint member and the shaft are joined. It is preferable to cover the part. Thus, by covering the joint with the boot, the joint is sealed and the joint is not exposed to the outside air.

  It is preferable that the inner diameter dimension of the small-diameter portion of the boot is larger than the outer diameter dimension of the inner joint member or the joint portion. By setting in this way, the joining operation between the inner joint member and the shaft can be facilitated. it can.

  Joining includes mechanical joining such as rivets, bolts and nuts, metallurgical joining, and the like. In this constant velocity universal joint, it is preferable to integrally join by friction welding or welding which is metallurgical joining. In addition, a difference in hardness is provided between the shaft joint portion of the inner joint member and the inner joint member joint portion of the shaft, and the joint is joined by plastic deformation on the lower hardness side by press-fitting between the shaft joint portion and the inner joint member joint portion. May be.

  According to the constant velocity universal joint of the present invention, since a retaining ring for retaining is not required, the number of parts and the number of processing steps can be reduced to achieve weight reduction and cost reduction. In addition, it is possible to provide a high-quality product that is excellent in productivity without requiring quality confirmation work for the presence or absence of a retaining ring. In addition, since the inner joint member and the shaft are not spline-fitted, there is no circumferential backlash, stable rotation transmission is possible, and there is no backlash noise or damage to the inner joint member or shaft.

  By covering the joint with boots, the joint is sealed, so that the joint is not exposed to the outside air, and corrosion or breakage at or near the joint due to external factors can be prevented. it can. Thereby, a stable function can be exhibited over a long period of time as a constant velocity universal joint.

The joining operation between the boot and the shaft can be facilitated, and the productivity can be further improved.

  The inner joint member and the shaft can be coupled with a stable coupling force by performing joint and integration by friction welding or by welding and integration. Moreover, if it is joining by plastic deformation, it is only necessary to press-fit, so that the joint workability can be improved.

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

  FIG. 1 shows a constant velocity universal joint according to the present invention. The constant velocity universal joint is a cross groove type, and includes an inner ring 53 as an inner joint member having an outer peripheral surface 52 in which ball grooves 51 twisted in opposite directions with respect to the axis are alternately formed in the circumferential direction, The outer ring 56 as an outer joint member having inner peripheral surfaces 55 alternately formed in the circumferential direction with ball grooves 54 twisted in opposite directions with respect to each other, and the balls of the inner ring 53 twisted in opposite directions with respect to the axis A torque transmission ball 57 interposed between the outer peripheral surface 52 of the inner ring 53 and the inner peripheral surface 55 of the outer ring 56 and a ball 57 as a torque transmission member incorporated at the intersection of the groove 51 and the ball groove 54 of the outer ring 56. Is held at a predetermined interval in the circumferential direction. In the embodiment, a non-float type in which the minimum inner diameter of the cage is larger than the maximum outer diameter of the inner ring is shown, but as a constant velocity universal joint, a float type in which the minimum inner diameter of the cage is smaller than the maximum outer diameter of the inner ring. There may be.

  The inner ring 53 includes a main body 53a in which a ball groove 51 is formed and a short cylindrical portion 53b protruding from the main body 53a, and a joint portion 62 formed between the short cylindrical portion 53b and the intermediate shaft 61 is interposed therebetween. Thus, the inner ring 53 and the shaft 61 are joined and integrated as shown in FIG.

  The intermediate shaft 61 includes a large-diameter main body portion 61a and a small-diameter end portion 61b connected to the main-body portion 61a via a taper portion 61c. The small-diameter end portion 61b has a diameter (inner diameter and outer diameter). The diameter is set to be substantially the same as the diameter (inner diameter and outer diameter) of the short cylindrical portion 53b of the inner ring 53.

  Here, the joining means joining and integrating the inner ring 53 and the shaft. The joining means (joining means) in this embodiment uses friction joining. Here, the friction welding means that two base materials are brought into contact with each other and relatively rotated to generate frictional heat on the contact surface by adding thrust. This is a method of softening the abutting surface and its vicinity by the heat and stopping the relative motion when the pressure temperature is reached, further increasing the pressure thrust and joining the two base materials. For this reason, the end surface of the short cylindrical portion 53b of the inner ring 53 and the end surface of the small-diameter end portion 61b of the shaft 61 are brought together to rotate either the inner ring 53 side or the intermediate shaft 61 side, or both. Thus, this friction welding can be performed. Thereby, the inner ring 53 and the shaft 61 are integrally fixed with the inner ring 53 and the intermediate shaft 61 in a state in which the axial centers thereof coincide with each other. That is, the joint portion 62 is formed in a state where a part of the inner ring 53 and the shaft 61 are abutted with each other.

  A joint portion 62 joined by friction joining is covered with a boot 64 that closes the opening 63 on the shaft protruding side of the outer ring 56. The boot 64 includes a large diameter portion 64a, a small diameter portion 64b, and a bellows portion 64c between the large diameter portion 64a and the small diameter portion 64b. The large-diameter portion 64 a is fixed to the outer ring 56 by being externally fitted to the mounting portion 65 on the outer diameter surface opening side of the outer ring 56 and fastening the boot band 66. The small diameter portion 64b is fixed to the shaft 61 by being externally fitted to a mounting portion 67 made of a thick portion provided on the taper portion 61c side of the main body portion 61a of the shaft 61 and fastening the boot band 68. As described above, the joint portion 62 is disposed in the space sealed by the boot 64.

  Further, since the small diameter portion 64 b is fitted on the mounting portion 67 of the main body portion 61 a of the shaft 61, the inner diameter dimension of the small diameter portion 64 b of the boot 64 is larger than the outer diameter dimension of the inner joint member or the joint portion 62. It has become. In addition, as a material of the boot 64, various things, such as rubber | gum and resin conventionally used for this kind of constant velocity universal joint, can be used.

  A circumferential groove 70 is formed on the inner diameter surface of the outer ring 56 on the opening side, and a retaining ring for preventing an internal part (an assembly of the inner ring 53, the ball 57, the cage, etc.) from being removed from the outer ring 56 in the circumferential groove 70. 71 is fitted.

  In the constant velocity universal joint of the present invention, since the shaft is joined and integrated with the inner joint member, a retaining ring for retaining is not required. For this reason, the number of parts and the number of processing steps can be reduced to achieve weight reduction and cost reduction. In addition, it is possible to provide a high-quality product that is excellent in productivity without requiring quality confirmation work for the presence or absence of a retaining ring. In addition, since the inner joint member and the shaft 61 are not spline-fitted, stable rotation transmission is possible without causing circumferential play, and noise due to play, damage to the inner joint member and the shaft 61 are also caused. Disappear.

  By covering the joint portion 62 with the boot 64, the joint portion 62 is sealed, so that the joint portion 62 is not exposed to the outside air, and corrosion or damage at or near the joint portion due to external factors. Can be prevented. Thereby, a stable function can be exhibited over a long period of time as a constant velocity universal joint.

  By making the inner diameter dimension of the small diameter portion 64b of the boot 64 larger than the outer diameter dimension of the inner joint member or the joining portion 62, the joining operation of the boot and the shaft 61 can be facilitated, and the productivity can be improved. More can be achieved.

  By using friction welding as the joining means as in the above embodiment, the inner joint member and the shaft 61 can be coupled with a stable coupling force. In addition, the preliminary surface treatment, which is the advantage of friction welding, is simple, the bonding time is short, and the friction welding has advantages such as high energy efficiency as compared with other bonding methods. Further, dissimilar metals can be joined, and the inner joint member and the shaft may be dissimilar metals.

  As the joining means, welding may be used as shown in FIG. In this case, a circumferential cutout 72 is provided in the short cylindrical portion 53b of the inner ring 53, and the end 73 of the small-diameter end 61b of the shaft 61 is fitted into the circumferential cutout 72. Welding. That is, the joining part 62 is formed in a state where a part of the inner ring 53 and the shaft 61 are overlapped with each other. In FIG. 3, reference numeral 75 denotes a bead portion. Conversely, a circumferential cutout 72 is provided on the small diameter end portion 61b side of the shaft 61, the short cylindrical portion 53b of the inner ring 53 is fitted into the circumferential cutout 72, and this fitting portion is welded in this state. Also good.

  Thus, even if welding is used for the joining means, the inner joint member and the shaft 61 can be coupled with a stable coupling force. In addition, as welding, various welding methods, such as arc welding and spot welding, can be used.

  As a joining means, as shown in FIG. 4, the shaft joining portion 77 and the inner joint member are provided with a hardness difference between the shaft joining portion 77 of the inner ring 53 and the inner joint member joining portion (inner ring joining portion) 78 of the shaft 61. Bonding by plastic deformation on the side having low hardness due to press-fitting with the bonding site 78 (plastic bonding) may be used.

  That is, the outer peripheral portion of the end portion on the inner ring side of the small-diameter end portion 61 b of the shaft 61 is subjected to a curing process (heat treatment) to form an inner ring joint portion 78, and the inner ring joint portion 78 is harder than the short cylindrical portion 53 b of the inner ring 53. To increase. Further, the outer diameter of the inner ring joint portion 78 is set slightly larger than the inner diameter of the short cylindrical portion 53 b of the inner ring 53. In this state, the small diameter end portion 61 b of the shaft 61 is press-fitted into the inner diameter surface of the short cylindrical portion 53 b of the inner ring 53. By this press-fitting, the shaft joint portion 77 on the inner diameter surface of the short cylindrical portion 53b of the inner ring 53 is plastically deformed, and the shaft joint portion 77 and the inner ring joint portion 78 are pressed (closely contacted) without a gap. As a result, the inner joint member 53 and the shaft 61 can be coupled. In this case as well, the joint portion 62 is formed in a state where the inner ring 53 and the shaft 61 are partially overlapped with each other.

  If it is joining by such plastic deformation, it is only necessary to press-fit, so that it is possible to improve the joining workability.

  As described above, the embodiments of the present invention have been described. However, the present invention is not limited to the above-described embodiments, and various modifications are possible. For example, the constant velocity universal joint may be a double offset type or a tripod type. May be. In the case of using plastic joining, in the embodiment, the hardness of the inner ring joint portion 78 is higher than the hardness of the shaft joint portion 77, but conversely, the hardness of the shaft joint portion 77 is higher than the hardness of the inner ring joint portion 78. May be higher. Furthermore, in the said embodiment, although the inner ring | wheel joining site | part 78 is arrange | positioned at the internal diameter side, you may arrange | position the shaft joint site | part 77 on the internal diameter side conversely. Further, the constant velocity universal joint may be for a propeller shaft or a drive shaft.

It is sectional drawing of the constant velocity universal joint which shows embodiment of this invention. It is an expanded sectional view of the joined part of the constant velocity universal joint. It is an expanded sectional view which shows the modification of the junction part of the said constant velocity universal joint. It is an expanded sectional view which shows the other modification of the junction part of the said constant velocity universal joint. It is sectional drawing of the conventional constant velocity universal joint. It is principal part sectional drawing of the said FIG. It is sectional drawing of the other conventional constant velocity universal joint. It is principal part sectional drawing of the said FIG.

Explanation of symbols

61 Shaft 62 Joint part 63 Opening part 64 Boot 64a Large diameter part 64b Small diameter part 77 Shaft joint part 78 Inner joint member joint part

Claims (6)

A constant velocity universal joint comprising an outer joint member and an inner joint member built in the outer joint member via a torque transmission member,
A constant velocity universal joint, wherein the inner joint member and the shaft are joined and integrated through a joint portion formed in a state in which a part of the inner joint member and the shaft are butted or overlapped with each other.   A boot having a large-diameter portion attached to the outer joint member and a small-diameter portion attached to the shaft to block the opening of the outer joint member on the shaft protruding side is provided. In this boot, the inner joint member and the shaft are joined. The constant velocity universal joint according to claim 1, wherein said constant velocity universal joint is covered.   The constant velocity universal joint according to claim 1 or 2, wherein the inner diameter dimension of the small diameter portion of the boot is made larger than the outer diameter dimension of the inner joint member or the joint portion.   The constant velocity universal joint according to any one of claims 1 to 3, wherein the constant velocity universal joint is integrated by friction welding.   The constant velocity universal joint according to any one of claims 1 to 3, wherein the constant velocity universal joint is integrated by welding.   A hardness difference is made between the shaft joint part of the inner joint member and the inner joint member joint part of the shaft, and joint integration is performed by plastic deformation on the side where the hardness is low due to press fitting between the shaft joint part and the inner joint member joint part. The constant velocity universal joint according to any one of claims 1 to 3, wherein

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