JP2005337304A - Constant velocity universal joint - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To design a torque transmitting ball to reduce a risk rate for riding on a shoulder of a track groove and a compact and lightweight universal joint while maintaining a satisfactory operation of the universal joint so that a cage offset angle of the universal joint arranged at an outboard side of a drive axle of a vehicle having no power steering is set to be a suitable value and a lacked offset angle of a track offset angle is exactly compensated. <P>SOLUTION: In the constant velocity universal joint (UJ) 1 arranged at an outboard side of a drive axle transmitting driving force to a wheel, a retainer 8 interposed between an outer joint member 2 and inner joint member 4 and storing and retaining torque transmitting balls 6 in respective pockets 7 is provided. Offset angles ϕc of respective spherical surfaces 8a and 8b of the retainer 8 are set in a range from 0° to less than 1°. Offset angles ϕa of respective track grooves 3 and 5 of the outer joint member 2 and the inner joint member 4 are preferably set in a range from 4 to 6°. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a constant velocity universal joint, and more particularly to an undercut-free type constant velocity universal joint disposed on an outboard side of a drive axle for a vehicle having no power steering.

  As is well known, in automobiles that do not have power steering and similar vehicles, even if there is an angular displacement or axial displacement between two axes in the power transmission path that transmits the driving force from the engine to the wheels. A constant velocity universal joint capable of transmitting rotational power at a constant speed has been provided. As an example, ATV (All Terrain Vehicle, also called a four-wheel buggy) is a four-wheel or three-wheel saddle-ride type vehicle for running on rough terrain. It is configured to run well on rough terrain. In this ATV power transmission device, as conceptually shown in FIG. 4, for example, the power of the engine 21 is output from the output shafts on the front side and the rear side through an internal transmission mechanism, and power transmission means such as a chain or a propeller shaft The signals are input to differentials 24 and 25 on the front side and the rear side via 22 and 23, respectively. The engine power input to the differentials 24 and 25 is decelerated by the mechanisms of the differentials 24 and 25, further converted into rotational power in a right angle direction, and transmitted to the wheels 28 and 29 via the left and right drive axles 26 and 27. Is done. In the example shown in the figure, constant velocity universal joints are used for the connecting portion A between the front drive axle 26 and the differential 24 and the connecting portion B with the wheel 28, respectively. A constant velocity universal joint may be used for the connecting portion C between the rear drive axle 27 and the differential 25 and the connecting portion D with the wheel 29, respectively.

  FIG. 5 shows the drive axle 26 on the front side. The drive axle 26 is connected to the slide type constant velocity universal joint (two-way joint) so that the drive axle 26 can be angularly displaced and axially displaced following the movement of the wheel 28 during cornering traveling or rough terrain traveling. A constant velocity universal joint 30 that allows angular displacement and axial displacement between shafts and a fixed type constant velocity universal joint (constant universal joint that allows angular displacement between two shafts) 31 are used in pairs. In the example shown in the figure, one end (inboard side) of the drive axle 26 is connected to a differential 24 via a sliding type constant velocity universal joint (double offset type constant velocity universal joint, hereinafter referred to as “DOJ”) 30. And the other end (outboard side) of the drive axle 26 through a fixed type constant velocity universal joint (Zepper type constant velocity universal joint: ball-fixed joint, hereinafter referred to as “BJ”) 31. It connects with the wheel 28 (connection part B).

  Conventionally, as the above-mentioned DOJ and BJ of a vehicle such as an ATV, it is frequently used by diverting a passenger car specification, but in a small vehicle such as an ATV with a narrow vehicle width, It is preferred to use a drive axle that is lightweight, compact and has good operability. In order to meet such a request, for example, according to Patent Document 1 below, in a drive axle that transmits driving force to a wheel via a constant velocity universal joint on the inboard side and the outboard side, a double offset is provided on the inboard side. It is disclosed that a type constant velocity universal joint (DOJ) uses an undercut-free type constant velocity universal joint (hereinafter referred to as “UJ”) on the outboard side.

  The UJ disposed on the outboard side of the drive axle basically has an outer joint member 12 having a plurality of track grooves 13 formed on a spherical inner peripheral surface 12a, as shown in FIG. An inner joint member 14 having a plurality of track grooves 15 formed on a spherical outer peripheral surface 14a, and a plurality of ball tracks disposed on the ball tracks formed by the opposing track grooves 13 and 15 of both the joint members 12 and 14. A torque transmission ball 16 and a cage 18 formed between the joint members 12 and 14 and formed with pockets 17 for holding the plurality of torque transmission balls 16 are provided.

  In the publication, it is described in claim 3 that the track offset angle of UJ is set to 5 ° to 7 °, and the cage offset amount of UJ is set to 0. Although described, paragraph [0010] of the publication discloses that the cage offset angle is set to 1 ° or more in the conventional UJ. That is, as shown in FIG. 6, the UJ is such that the centers Oaa and Obb of the track grooves 13 and 15 of the outer joint member 12 and the inner joint member 14 are on opposite sides in the axial direction with respect to the joint center O. It is offset by the distance Laa, and the track offset angle φaa (offset angle of the track grooves 13 and 15) made of ∠OaaQO (or ∠ObbQO) is set to 5 ° to 7 °. In this case, since the cage offset amount is 0, Lcc in the figure is 0. Further, in the conventional UJ, the centers Occ and Odd of the inner and outer spherical surfaces 18a and 18b of the cage 18 are offset by an equal distance Lcc on the opposite side in the axial direction with respect to the joint center O, and ∠OddQO (or A cage offset angle φcc composed of オ フ セ ッ ト OccQO (offset angle of each spherical surface 18a, 18b of the cage 18) is set to 1 ° or more. In the following description, the sum of the track offset angle and the cage offset angle φcc is referred to as a total offset angle (φaa shown in FIG. 6). Therefore, the track offset amount in FIG. 6 is an amount obtained by subtracting the cage offset amount Lcc from the total offset amount Laa (Laa-Lcc).

JP 2001-97063 A

  By the way, it is known that when the above-described total offset angle is increased, the operability of the UJ and thus the steering performance is improved. However, if the track offset angle is too large, the outer joint member 12 on the outboard side is improved. Since the track groove 13 becomes excessively shallow, the above-described cage offset angle exists in order to compensate for the shortage of the track offset angle after setting the track offset angle to be appropriately small. Therefore, when it is desired to ensure a sufficient total offset angle, it is extremely advantageous in terms of design to include a cage offset angle in addition to the track offset angle.

  In this case, as described in Patent Document 1 (Claim 3), when the cage offset angle is set to 0 °, the shortage of the track offset angle cannot be compensated, which is disadvantageous in design. On the other hand, as described in the same document (paragraph [0010]), when the cage offset angle is 1 ° or more, the track offset angle should be increased in consideration of the geometric balance with the cage offset angle. Is preferable in terms of design. Based on such a design concept, when the track offset angle is increased so as to correspond to a cage offset angle of 1 ° or more, the track groove on the outboard side of the outer joint member becomes shallow as described above. For this reason, not only the risk of climbing the shoulder of the torque transmission ball increases, but it also hinders the reduction in size and weight of UJ.

  The present invention has been made in view of the above circumstances, and by setting the cage offset angle of the UJ disposed on the outboard side of a drive axle for a vehicle having no power steering to an appropriate value, the truck offset The technical problem is to reduce the risk of climbing the shoulder of the torque transmission ball and reduce the size and weight of the UJ while accurately compensating for the shortage of corners and maintaining the good operability of the UJ.

  The present invention, which has been made to solve the above technical problem, is disposed on the outboard side of a drive axle for transmitting a driving force to a wheel in a vehicle (for example, ATV) having no power steering, and has a spherical inner peripheral surface. Respectively, and an outer joint member having a plurality of track grooves, an inner joint member having a plurality of track grooves on a spherical outer peripheral surface, and a plurality of ball tracks formed by the opposing track grooves of the both joint members. An undercut-free constant velocity universal joint provided with a torque transmission ball and a cage interposed between the two joint members and storing and holding the torque transmission ball in a plurality of window-shaped pockets, respectively. Each track groove center of the outer joint member and the inner joint member and each spherical center inside and outside of the cage are axially based on the joint center. Causes offset, the offset angle of each spherical surface of the cage, is characterized in that the set below and 1 ° in 0 ° greater.

  According to such a configuration, since the offset angle of each spherical surface on the inner peripheral side and the outer peripheral side of the cage in the UJ for vehicles not having power steering, that is, the cage offset angle, is over 0 °, the track offset angle is insufficient. It is possible to compensate for this, and it is advantageous in terms of design, and it is possible to enjoy the advantages of providing a moderate total offset angle without unduly shallowing the track groove on the outboard side of the outer joint member. Become. Moreover, since the cage offset angle is less than 1 °, the track groove on the outboard side of the outer joint member is appropriately deepened while maintaining a good geometrical balance between the cage offset angle and the track offset angle. It is possible to improve the durability by reducing the risk of climbing the shoulder of the torque transmission ball, and to further reduce the size and weight. In addition, if the cage offset angle increases, the axial thickness deviation of the cage increases and the hole punching workability of the pocket portion deteriorates. However, when the cage offset angle is less than 1 ° as described above. If the geometrical balance with the track offset angle is maintained well, it is possible to effectively avoid such problems. Considering the above matters, the cage offset angle is more preferably 0.5 ° to 0.8 °.

  In the above configuration, the offset angle of each track groove of the outer joint member and the inner joint member is preferably set to 4 ° to 6 °, and more preferably set to 5 ° or 5.3 °. .

  In this way, the total offset angle including the offset angle of each track groove, that is, the track offset angle is determined in consideration of the fact that the cage offset angle is set to be more than 0 ° and less than 1 ° as described above. In addition, it is possible to achieve an optimum angle that simultaneously satisfies the reduction in the risk of climbing the shoulder of the torque transmission ball, the reduction in size and weight of UJ, and the improvement in operability or steering performance.

  In the above configuration, it is preferable that the end portion on the inboard side of the cage protrudes from the end portion on the inboard side of the outer joint member in a state where the operating angle is 0 °.

  In this way, since the widthwise dimension of the cage can be made relatively long, it is possible to secure a sufficient width of meat on both sides of the cage pocket in the widthwise direction, as described above. In combination with the appropriate value, it is possible to improve the durability of the cage.

  The said structure WHEREIN: It is preferable that all the several window-shaped pockets of a holder | retainer are formed in the same magnitude | size.

  That is, conventionally, for example, when the inner joint member is assembled into the cage, the convex portion between the adjacent track grooves of the inner joint member is inserted into the cage pocket in a state where it is incorporated. Was used, the specific pocket used for insertion of the convex part had to be made larger than other pockets. The pockets can be made the same size without being unduly enlarged. Therefore, partial strength reduction of the cage can be prevented, and it becomes possible to further improve the durability of the cage in combination with the appropriate offset angle as described above. .

  The constant velocity universal joint having the above-described configuration is preferably provided in a saddle-ride type vehicle (ATV) for traveling on rough terrain.

  As described above, according to the constant velocity universal joint according to the present invention, the cage offset angle in the UJ for a vehicle having no power steering is set to more than 0 ° and less than 1 °, so that the shortage of the track offset angle is compensated. In addition to being advantageous in terms of design, it is possible to simultaneously satisfy the reduction in the risk of climbing the shoulder of the torque transmission ball, the reduction in size and weight, and the improvement in operability and hence the steering performance.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The constant velocity universal joint according to the embodiment of the present invention is disposed on the outboard side of the drive axle 26 (27) already described with reference to FIG. 4, and the drive axle is already shown in FIG. Therefore, in the following description, only the constant velocity universal joint and its peripheral part will be described.

  FIG. 1 illustrates a state when the operating angle θ of the underfree cut type constant velocity universal joint 1 for ATV according to the first embodiment of the present invention is 0 °, and FIG. 2 illustrates the constant velocity universal joint 1. This illustrates the state when the operating angle θ takes the maximum operating angle (for example, 50 °). As shown in these drawings, the constant velocity universal joint 1 is an outer joint member in which a plurality (six or eight) bottom curved track grooves 3 are formed in an axial direction on a spherical inner peripheral surface 2a. 2 (outer ring), an inner joint member 4 (inner ring) in which a plurality of (6 or 8) bottom curved track grooves 5 are formed in the axial direction on a spherical outer peripheral surface 4a, both joint members 2, A plurality of (6 or 8) torque transmission balls 6 respectively disposed on each ball track formed by four opposing track grooves 3 and 5 and the joint members 2 and 4 interposed between each other and each A cage 8 (cage) for storing and holding the torque transmission balls 6 in a plurality of window-shaped pockets 7 is provided. Then, the intermediate shaft 9 (see FIG. 5) of the drive axle is coupled to the inner periphery of the inner joint member 4 via serrations and the like, and the wheel side member is coupled to the stem portion 2x of the outer joint member 2.

  As shown in FIG. 1, the ball track formed by the track groove 3 of the outer joint member 2 and the track groove 5 of the inner joint member 4 is wide on the inboard side (right side in the figure) and on the outboard side (same figure). It shows a shape (wedge shape) that is gradually reduced toward the left side. In this case, straight portions 2b and 4b each having a straight groove bottom in the longitudinal section are formed on the inboard side portion of the track groove 3 of the outer joint member 2 and the outboard side portion of the track groove 5 of the inner joint member 4, respectively. The maximum operating angle is set to 50 °, which is larger than the maximum operating angle (46.5 °) of a conventional passenger car BJ, due to the presence of the straight portions 2b and 4b.

  The center Od of the spherical surface 8b on the inner peripheral side of the cage 8 is offset by a distance Lc from the joint center O to the outboard side along the axial direction, and torque transmission with the center Od of the spherical surface 8b on the inner peripheral side is performed. The cage offset angle φc formed by the flange OdQO formed by the center Q of the ball 6 and the joint center O, that is, the offset angle of the inner spherical surface 8b of the cage 8 is more than 0 ° and less than 1 ° (preferably 0.5 ° ˜0.8 °, in this embodiment 0.7 °). Further, the center Oc of the spherical surface 8a on the outer peripheral side of the cage 8 is offset by an equal distance Lc from the joint center O to the inboard side along the axial direction, and the center Oc of the spherical surface 8a on the outer peripheral side. The cage offset angle formed by the flange OcQO formed by the center Q of the torque transmission ball 6 and the joint center O also exceeds 0 ° and is less than 1 ° (preferably 0.5 ° to 0.8 °, In this embodiment, it is set to 0.7 °. Although not shown, the diameter of the spherical inner peripheral surface 2a of the outer joint member 2 and the diameter of the spherical surface 8b on the inner peripheral side of the cage 8 are about 5 to 10 μm at both ends from the axial center. In contrast, the diameter of the spherical surface 8a on the outer peripheral side of the cage 8 and the diameter of the spherical outer peripheral surface 4a of the inner joint member 4 are 5 to 10 μm at both ends relative to the central portion in the axial direction. It has been enlarged to a certain extent. Thereby, the inner peripheral surface 2a of the outer joint member 2 and the outer spherical surface 8a of the cage 8 are brought into contact from both ends in the axial direction, and the inner spherical surface 8b of the cage 8 and the outer circumferential surface 4a of the inner joint member 4 are also contacted. Contact is made from both ends in the axial direction. Therefore, each spherical surface that is in contact is a two-point contact, and the position of the spherical surface portion is stabilized accordingly.

  On the other hand, the center Oa of the track groove 3 of the outer joint member 2 is offset by a distance La from the joint center O to the inboard side along the axial direction, and the center Oa of the track groove 3 of the outer joint member 2 The track offset angle of the outer joint member 2 is φa−φc from the total offset angle φa formed by the flange OaQO formed by the center Q of the torque transmission ball 6 and the joint center O, and the offset angle of the track groove 3 of the outer joint member 2 Is set to 4 ° to 6 ° (5 ° in this embodiment). The center Ob of the track groove 5 of the inner joint member 4 is offset from the joint center O along the axial direction by the same distance La to the outboard side. The track offset angle of the inner joint member 4 obtained from the total offset angle formed by the flange ObQO formed by the center Ob, the center Q of the torque transmission ball 6 and the joint center O is also 4 ° to 6 ° (this implementation) In the form, it is set to 5 °).

  The diameter Dx of the opening 8x at the end on the outboard side of the retainer 8 is set larger than the diameter Dy of the opening 8y at the end on the inboard side, and the inner joint member passes through the opening 8x on the outboard side. 4 is configured to be inserted into and removed from the inside of the cage 8. In this case, the diameter Dy of the opening 8 y on the inboard side is set to be small enough that the inner joint member 4 cannot be inserted into and removed from the inside of the cage 8.

  More specifically, the outer peripheral surface 8a of the cage 8 has a substantially spherical surface (region excluding the chamfered portions at both ends in the axial direction), while the inner peripheral surface 8b has an axial central region (pocket). 7 is a spherical surface 8b1, and a surface continuous with the spherical surface 8b1 is a cylindrical surface 8b2 on the outboard side and a spherical surface 8b3 on the inboard side. Yes. In this case, the cylindrical surface 8b2 on the outboard side continuously extends to the end thereof with substantially the same diameter, whereas the spherical surface 8b3 on the inboard side is further on the inboard side on the outboard side. A cylindrical surface 8b4 having a smaller diameter and a smaller axial width than the cylindrical surface 8b2 is continuously formed.

  Therefore, the thickness of the cage 8 gradually decreases as it moves from the axial central region toward the outboard side, whereas it changes until a predetermined dimension shifts from the axial central region toward the inboard side. During this period, it gradually increases due to the cage offset. In other words, the average thickness of the inboard side portion is set to be larger than the average thickness of the outboard side portion than the central region in the axial direction of the cage 8. Furthermore, the contact area between the inner peripheral surface 8b of the cage 8 and the outer peripheral surface 4a of the inner joint member 4 is set to be narrower on the outboard side than on the inboard side. Accordingly, the contact area between the both axial sides of the pocket 7 on the inner peripheral surface 8b of the cage 8 and the outer peripheral surface 4a of the inner joint member 4 is extremely narrow on the outboard side, whereas on the inboard side, It is set to be wider than that.

  In addition, the end portion on the inboard side of the cage 8 protrudes from the end portion on the inboard side of the outer joint member 2, whereby the axial width of the cage 8 is relatively long. . Further, the plurality of pockets 7 formed at equal intervals in the circumferential direction of the cage 8 are all set to the same size (the same axial width and circumferential length).

  According to the constant velocity universal joint 1 having the above-described configuration, the offset angle, that is, the cage offset angle φc of the spherical surfaces 8a and 8b on the inner peripheral side and the outer peripheral side of the cage 8 exceeds 0 ° (preferably 0. Over 5 °), the shortage of the track offset angle can be compensated efficiently, which is advantageous in terms of design and is moderate without causing the track groove 3 on the outboard side of the outer joint member 2 to be unduly shallow. It is possible to ensure a large total offset angle.

  Moreover, since the cage offset angle φc is less than 1 ° (preferably less than 0.8 °), the outer joint member maintains a good geometrical balance between the cage offset angle φc and the track offset angle. Accordingly, the track groove 3 on the outboard side 2 can be made appropriately deep. As a result, it is possible to reduce the risk of climbing the shoulder of the torque transmission ball 6 to improve durability, and to reduce the size and weight of the constant velocity universal joint 1.

  In this case, if the total offset angle increases, the workability of the pocket 7 of the cage 8 deteriorates. However, when the cage offset angle φc is less than 1 ° as described above, By maintaining a good geometric balance, problems such as deterioration in workability are less likely to occur.

  In addition, since the offset angle of each track groove 3, 5 of the outer joint member 2 and the inner joint member 2, that is, the track offset angle is set to 4 ° to 6 °, the cage offset angle φc as described above. Taking into account the fact that the angle is set to more than 0 ° and less than 1 °, the total offset angle between the track offset angle and the cage offset angle φc is reduced, and the risk of climbing the shoulder of the torque transmission ball 6 is reduced. It is possible to make the speed universal joint 1 smaller and lighter and to improve the operability or steering performance at an optimum angle satisfying all at once.

  FIG. 3 illustrates an under-free cut type constant velocity universal joint 1 for ATV according to the second embodiment of the present invention (state when the operating angle θ is 0 °). The constant velocity universal joint 1 according to the second embodiment is different from the constant velocity universal joint 1 according to the first embodiment described above in that the cage 8 is incorporated reversely with respect to the axial direction. That is, the relatively large-diameter opening 8x of the cage 8 is located on the inboard side, and the relatively small-diameter opening 8y is located on the outboard side. Since other configurations are the same as those of the constant velocity universal joint 1 according to the first embodiment described above, in FIG. 3, the same reference numerals are given to the constituent elements common to both embodiments, and the description thereof is omitted. . And also about the constant velocity universal joint 1 which concerns on this 2nd Embodiment, the effect similar to the constant velocity universal joint 1 which concerns on the above-mentioned 1st Embodiment can be obtained.

  In the above embodiment, the present invention is applied to the ATV. However, the present invention can be similarly applied to other vehicles as long as the vehicle does not have power steering. It is.

It is a principal part longitudinal front view which shows the state when the constant velocity universal joint which concerns on 1st Embodiment of this invention is an operating angle of 0 degree. It is a principal part longitudinal front view which shows a state when the constant velocity universal joint which concerns on 1st Embodiment of this invention takes the maximum operating angle (for example, 50 degrees). It is a principal part longitudinal front view which shows the state when the constant velocity universal joint which concerns on 2nd Embodiment of this invention is an operating angle of 0 degree. It is a schematic plan view which shows the power transmission device of the vehicle (for example, ATV) equipped with the constant velocity universal joint which concerns on 1st, 2nd embodiment of this invention. It is a principal part fracture | rupture front view which shows the drive axle by which the constant velocity universal joint which concerns on 1st, 2nd embodiment of this invention and the constant velocity universal joint which concerns on a prior art example are arrange | positioned at the end of an axial direction. It is a principal part vertical front view which shows the conventional constant velocity universal joint.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Constant velocity universal joint 2 Outer joint member 2a Outer joint member inner peripheral surface 3 Outer joint member track groove 4 Inner joint member 4a Inner joint member outer peripheral surface 5 Inner joint member track groove 6 Torque transmission ball 7 Pocket 8 Holding Cage 8a Cage outer peripheral surface 8b Cage inner peripheral surface 8b1 Axial central region spherical surface 8b2 Cylinder surface 8b3 Inboard side spherical surface 8x Cage outboard side opening 8y Cage inboard side opening O Joint center Oa Track groove center Ob of the outer joint member Track groove center Oc of the inner joint member Spherical center Od on the outer circumference side of the cage Od Spherical center on the inner circumference side of the cage φa Track offset angle φc Cage offset angle

Claims (5)

An outer joint member having a plurality of track grooves on a spherical inner peripheral surface and a plurality of spherical outer peripheral surfaces arranged on the outboard side of a drive axle that transmits a driving force to a wheel in a vehicle having no power steering An inner joint member having a plurality of track grooves, a torque transmitting ball disposed on each of a plurality of ball tracks formed by opposing track grooves of the two joint members, and the torque interposed between the two joint members. In an undercut-free type constant velocity universal joint with a cage for storing and holding the transmission balls in a plurality of window-shaped pockets,
Each track groove center of the outer joint member and the inner joint member and each spherical center inside and outside the cage are offset in the axial direction with reference to the joint center, and the offset angle of each spherical surface of the cage is A constant velocity universal joint characterized in that it is set to be more than 0 ° and less than 1 °.   The constant velocity universal joint according to claim 1, wherein an offset angle of each track groove of the outer joint member and the inner joint member is set to 4 ° to 6 °.   The end portion on the inboard side of the retainer protrudes from the end portion on the inboard side of the outer joint member when the operating angle is 0 °. Fast universal joint.   The constant velocity universal joint according to any one of claims 1 to 3, wherein the plurality of window-shaped pockets of the cage are all formed in the same size.   The constant velocity universal joint according to any one of claims 1 to 4, wherein the constant velocity universal joint is installed in a saddle-ride type vehicle for traveling on rough terrain.