JP2005337305A - Constant velocity universal joint - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To avoid a deteriorated steering property caused by enlargement of bending resistance at the time of steering and reduction of a steering feeling caused by generation of noises and a hooked feeling by setting an axial pocket gap δ of a universal joint arranged on an outboard side of a drive axle of a vehicle having no power steering. <P>SOLUTION: In the constant velocity universal joint (UJ) 1 arranged on an outboard side of the drive axle transmitting driving force to a wheel, the UJ provides a retainer 8 which is interposed between an outer joint member 2 and an inner joint member 4 and stores and retains torque transmitting balls 6 in respective pockets 7, and an axial pocket gap δ between the pocket 7 and the torque transmitting ball 6 of the retainer 8 is set in a range of -30≤δ≤0 μm. The retainer is preferably made of steel, and inner peripheral surfaces of the pockets 7 are formed by machining or grinding original inner peripheral surfaces of the quenched pockets. <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. 5, for example, the power of the engine 21 is output from the output shafts on the front side and the rear side via 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. 6 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 this type of constant velocity universal joint (UJ), from the viewpoint of improving the guiding function of the torque transmission ball 16 by the cage 18 and placing importance on ensuring the constant velocity of the joint, the torque and the pocket 17 of the cage 18 A value δ obtained by subtracting the diameter of the torque transmission ball 16 from the axial clearance δ between the transmission ball 16, that is, the axial width of the pocket 17 is set to δ <0 (negative clearance). It is customary to give an allowance between In this case, when the axial clearance δ is small (when it is excessively negative), the torque transmission ball 16 is difficult to roll on the ball track and in the pocket 17, so this type of joint has an operating angle. However, it is disadvantageous in terms of rotational resistance when transmitting rotational torque, and adversely affects steering performance. On the other hand, when the axial clearance δ is increased (when the positive clearance is excessively increased), although the rolling performance of the torque transmitting ball 16 is enhanced and the rotational resistance is reduced, the torque generated by the cage 18 is increased. Since the guide function of the transmission ball 16 is hindered and the constant velocity of this type of joint is lost, abnormal noise is generated, a feeling of catching, and the like are caused, which causes a decrease in steering feeling.

  In addition, the axial pocket clearance δ of the constant velocity universal joint installed in a general automobile including a passenger car is defined instead of the constant velocity universal joint installed in a vehicle having no power steering, which is the subject of the present invention. As described above, there are technologies disclosed in Patent Documents 2 and 3 below.

JP 2001-97063 A JP 2000-266071 A Japanese Patent Laid-Open No. 2002-5186

  By the way, in the constant velocity universal joint arranged on the outboard side of the drive axle in a vehicle having no power steering represented by ATV or the like, the basic shape of the cage is first formed by press working or the like as the manufacture of the cage. After molding, a method of removing a pocket from a window and then performing a heat treatment has been adopted. However, in this method, the pocket windowing process is special, or due to deformation after heat treatment, distortion or taper is formed on the inner peripheral surface of the pocket, or a dimensional error has occurred. For this reason, the actual situation is that the axial pocket gap δ must be set to, for example, about −60 μm or even smaller. For this reason, the axial pocket gap δ becomes excessively small, causing not only a problem such as an unduly large bending resistance or load during steering, but also an axial pocket gap δ due to a pocket dimensional error or the like. On the contrary, there is a concern that the gap may become a regular gap and the operability or constant velocity of this type of joint may be lost.

  That is, since this type of vehicle does not have power steering, the above-described axial pocket gap δ greatly affects the bending resistance and steering performance of the steering wheel. However, the actual situation is that the axial pocket gap δ is not set to an appropriate range only for vehicles having no power steering.

  The present invention has been made in view of the above circumstances, and by setting the axial pocket clearance δ of the UJ disposed on the outboard side of a drive axle for a vehicle having no power steering to an appropriate value. Further, it is a technical object to avoid deterioration in steering performance due to an increase in bending resistance or load during steering, and at the same time, avoid a decrease in steering feeling due to occurrence of abnormal noise or a feeling of catching.

  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. The axial pocket gap δ between the pocket of the cage and the torque transmitting ball is set to −30 μm ≦ δ ≦ 0 μm. Is shall.

  According to such a configuration, the axial pocket clearance δ is within an appropriate range for a constant velocity universal joint (UJ) disposed on the outboard side of a drive axle in a vehicle having no power steering such as ATV. As a result, the deterioration of steering performance due to bending resistance or increased load during steering, and the deterioration of steering feeling due to the occurrence of abnormal noise or a feeling of catching, etc. It is effectively avoided at the same time. That is, if the axial pocket gap δ is smaller than −30 μm (δ <−30 μm), the torque transmission ball is difficult to roll in the pocket, and the bending resistance when this type of joint takes an operating angle is reduced. Alternatively, the load becomes unreasonably large, which adversely affects steering performance. On the other hand, when the axial pocket gap δ is larger than 0 μm (δ> 0 μm), the function of guiding the torque transmitting ball by the cage is hindered, and the operability or constant velocity of this type of joint is lost. Abnormal noise, a feeling of catching, etc. occur, causing a decrease in steering feeling. Therefore, if the axial pocket gap δ is within the above numerical range, an appropriate joint operation is performed in this type of vehicle. Considering such matters, it is more preferable that the upper limit of the axial pocket gap δ is 0 μm (δ <0 μm) and the lower limit is −20 μm (δ ≧ −20 μm).

  In the above configuration, the cage is preferably made of steel, and the inner peripheral surface of the pocket is preferably formed by cutting or grinding the original inner peripheral surface of the pocket formed by quenching.

  In this way, as a manufacture of the cage, for example, after first forming the basic shape of the cage made of steel by press processing or the like, after performing the window opening processing of the pocket, after that, applying a quenching process, Thereafter, a method is employed in which the final inner peripheral surface of the pocket is obtained by cutting or grinding the original inner peripheral surface of the pocket formed by the window cutting process. As described above, by performing cutting or grinding after the quenching process, it is possible to avoid the formation of a taper or distortion on the inner peripheral surface of the pocket as much as possible, as well as variations and dimensional errors. Can form a pocket in which deformation is suppressed as much as possible, and an appropriate axial pocket gap δ can be stably obtained.

  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 sufficient width meat portions on both sides in the widthwise direction of the cage pocket, and to improve the strength of the cage. It becomes possible to plan.

  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 the pocket shape can be made the same, so that the workability at the time of cutting or grinding of the pocket is also improved.

  The constant velocity universal joint having the above-described configuration is preferably installed 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 axial pocket gap δ in the UJ for a vehicle not having power steering is set to −30 μm ≦ δ ≦ 0 μm. The deterioration of the steering performance due to the increase in load and the reduction in steering feeling due to the occurrence of abnormal noise or the occurrence of a catching feeling can be effectively avoided at once.

  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. 6 will be described below, only the constant velocity universal joint and its peripheral part will be described below.

  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, an intermediate shaft 9 (see FIG. 6) of the drive axle is coupled to the inner periphery of the inner joint member 4 via serrations and the like, and a wheel-side component 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).

  In this case, as shown in FIG. 3, a value obtained by subtracting the diameter d1 of the torque transmission ball 6 from the axial width t1 of the pocket 7 of the cage 8 (the pocket 7 before the torque transmission ball 6 is fitted), that is, holding The axial pocket clearance δ between the pocket 7 of the device 8 and the torque transmission ball 6 is set to −30 μm ≦ δ ≦ 0 μm. The axial pocket gap δ is more preferably set to −20 μm ≦ δ <0 μm. The torque transmitting ball 6 is fitted in the pocket 7 of the cage 8 so as to be slightly movable in the circumferential direction.

  The cage 8 is made of steel such as chrome steel or chrome molybdenum steel, and the outline of the manufacturing method is, for example, that the basic shape (ring body) of the cage 8 is first formed by pressing or the like. After that, the window 7 of the pocket 7 is subjected to a window cutting process, and after that, a quenching process is performed, and then the former inner peripheral surface of the pocket 7 formed by the window cutting process (uncut or unground after the window cutting process) The inner peripheral surface) is cut or ground to finally obtain the inner peripheral surface of the pocket 7.

  According to the constant velocity universal joint 1 having the above-described configuration, the axial pocket clearance δ between the pocket 7 of the cage 8 and the torque transmission ball 6 is larger than −30 μm (preferably −20 μm). As a result, the torque transmission ball 6 easily rolls in the pocket 7, and the bending resistance or load when this type of joint takes an operating angle is appropriately reduced, so that the steering performance is improved. Further, since the axial pocket gap δ is smaller than 0 μm, the function of guiding the torque transmitting ball 6 by the cage 8 is smoothly performed, and the operability or constant velocity of this type of joint is maintained well. As a result, the generation of abnormal noise and the feeling of catching are less likely to occur, and the steering feeling is improved.

  In addition, when the cage 8 is manufactured, by performing cutting or grinding after the quenching process, it is avoided as much as possible that the inner peripheral surface of the pocket 7 is tapered or distorted. At the same time, it is possible to form the pocket 7 in which variations, dimensional errors, and deformation are suppressed, and an appropriate axial pocket gap δ can be stably obtained.

  FIG. 4 illustrates an underfree cut type constant velocity universal joint 1 (state when the operating angle θ is 0 °) for ATV according to the second embodiment of the present invention. 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. . 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 vertical front view which shows the holder | retainer of the constant velocity universal joint which concerns on 1st Embodiment of this invention. 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 Cylindrical surface 8b3 Inboard side spherical surface 8x Cage outboard side opening 8y Cage inboard side opening

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,
A constant velocity universal joint characterized in that an axial pocket clearance δ between the pocket of the cage and the torque transmitting ball is set to −30 μm ≦ δ ≦ 0 μm.   The constant velocity according to claim 1, wherein the cage is made of steel, and the inner peripheral surface of the pocket is formed by cutting or grinding the original inner peripheral surface of the pocket formed by quenching. Universal joint.   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.