JP2007092964A - Cross groove type constant velocity universal joint - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cross groove type constant velocity universal joint capable of improving the strength of a column part of a cage to prevent the column part of the cage from being broken even when excessive torque is inputted. <P>SOLUTION: This cross groove type constant velocity universal joint is provided with an inner ring 2 forming ball grooves 2a, 2b inclined in the reverse direction for each other in the circumferential direction alternately and an outer ring 4 forming ball grooves 4a, 4b inclined in the reverse direction for each other in the circumferential direction alternately. Torque transmission balls 6 are incorporated into crossing parts of the ball grooves 2a, 2b, 4a, 4b of the inner ring 2 and the outer ring 4 inclined in the reverse direction for each other, and a cage 8 for holding these torque transmission balls 6 is provided. In this cage 8, inside diameter of a central part in the axial direction is the same as inside diameter of an end part, and an inner peripheral face has a cylindrical shape. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a constant velocity universal joint used in a power transmission device for automobiles and various industrial machines, and more particularly to a cross having a ball groove in which an inner ring and an outer ring are inclined in opposite directions with respect to an axis line. The present invention relates to a groove type constant velocity universal joint.

  In the cross groove type constant velocity universal joint, the ball groove of the inner ring and the ball groove of the outer ring that form a pair are inclined in opposite directions with respect to the axis, and the torque transmission ball is held at the intersection of both ball grooves. ing. Because of such a structure, rattling between the torque transmitting ball and the ball groove can be reduced, and in particular, it is frequently used for drive shafts and propeller shafts of automobiles that do not like rattling.

  Non-Patent Document 1 shows the most basic cross groove type constant velocity universal joint. The basic configuration of the cross-groove type constant velocity universal joint consists of an inner ring having an outer peripheral surface in which ball grooves inclined in opposite directions with respect to the axis are alternately formed in the circumferential direction, and inclined in directions opposite to each other with respect to the axis. An outer ring having an inner peripheral surface in which ball grooves are alternately formed in the circumferential direction; a torque transmission ball incorporated at the intersection of the inner ring ball groove and the outer ring ball groove inclined in opposite directions with respect to the axis; The cage is interposed between the outer peripheral surface of the inner ring and the inner peripheral surface of the outer ring and holds the torque transmission balls at a predetermined interval in the circumferential direction. In Non-Patent Document 1, the number of rolling elements is four or more, and generally six.

Further, in Patent Document 1, in the above-described basic cross groove type constant velocity universal joint, in order to prevent the maximum operating angle from being reduced when the cross angle of the ball groove with respect to the axis is reduced, A cross-groove type constant velocity universal joint that has been proposed to be inclined not only with respect to the axis but also within a plane including the axis is described.
JP-A-5-231435 ERWagner, “Universal Joint and Driveshaft Design Manual”, SAE, 1991, p.163-166

  As shown in FIGS. 11 and 12, the cage 10 of the conventional cross groove type constant velocity universal joint including the cross groove type constant velocity universal joint described in Non-Patent Document 1 and Patent Document 1 has a central portion in the axial direction. The inner peripheral surface of 10a is cylindrical, and the inner diameter thereof is larger than the inner diameter of the axial end portion 10b. The central portion 10a and the axial end portion 10b are spherical portions 10c (see FIG. 11) or tapered surfaces. It has the shape which continues through 10d (refer FIG. 12).

  The cage 10 is provided with window-like pockets 10e corresponding to the number of torque transmission balls. The pocket 10e accommodates and holds the torque transmission ball and functions to position the torque transmission ball at the intersection of the ball groove of the inner ring and the ball groove of the outer ring. Due to the structure of the cross groove type constant velocity universal joint, the directions of the loads applied to the torque transmitting balls when torque is input are opposite to each other in the adjacent pockets 10e. For this reason, the load which acts in the reverse direction is applied to the column part 10f which is a site | part between pockets. That is, the column portion 10f is pulled. In the conventional cross groove type constant velocity universal joint, a load acting in the opposite direction is applied to the column portion 10f as described above, and the cage 10 has a small thickness in the radial direction of the column portion 10f as described above. If an excessive torque is input, the pillar portion 10f of the cage 10 may be damaged.

  An object of the present invention is to improve the strength of a cage column portion in a cross groove type constant velocity universal joint so that the cage column portion is not damaged even when an excessive torque is input.

  The cross groove type constant velocity universal joint of the present invention includes an inner ring having an outer peripheral surface in which ball grooves inclined in opposite directions with respect to the axis are alternately formed in a circumferential direction, and inclined in directions opposite to each other with respect to the axis. An outer ring having an inner peripheral surface in which ball grooves are alternately formed in the circumferential direction; a torque transmission ball incorporated at the intersection of the inner ring ball groove and the outer ring ball groove inclined in opposite directions with respect to the axis; A cage interposed between the outer peripheral surface of the inner ring and the inner peripheral surface of the outer ring and holding the torque transmitting balls at a predetermined interval in the circumferential direction, and the inner diameter of the cage in the axial center is the inner diameter of the end And the inner peripheral surface of the cage is cylindrical.

  The inner diameter of the cage in the axial center is the same as the inner diameter of the end, and the inner peripheral surface of the cage is cylindrical, so that the radial direction of the column that is the part between the pockets that accommodates torque transmitting balls in the cage The thickness of the column increases, and the strength of the column portion is improved. For this reason, even when an excessive torque is input to the joint and a load acting in the opposite direction is greatly applied to the column portion, the column portion of the cage is not damaged.

  In this invention, the ball grooves of the inner ring and the outer ring that are inclined in opposite directions have an intersection angle of 4.5 ° or more and 8.5 ° or less with the axis of the inner ring or outer ring, respectively, and the number of torque transmitting balls is 8 can be used.

By making the crossing angle of the ball groove with respect to the axis line 4.5 ° or more and 8.5 ° or less and the number of the torque transmitting balls 8, the maximum operating angle of the joint will not be reduced and the sliding stroke will be increased. Can do. In a cross-groove type constant velocity universal joint, there is a torque transmission ball at a certain phase, and when the operating angle is increased, the wedge angle, which is the intersection angle of the ball grooves of the inner and outer rings, is reversed, and the torque transmission ball is transferred to the cage. The balance of the acting force is lost and the drive of the cage becomes unstable. As the wedge angle becomes smaller, this phenomenon becomes prominent when the number of torque transmitting balls is up to six. However, when the number of torque transmission balls is 8 or more, even if the wedge angle is reduced, the driving force of the torque transmission ball whose wedge angle is reversed is shared by other torque transmission balls, The drive of the cage can be stabilized.
When the number of torque transmission balls is increased from 6 to 8 or 10 as will be described later and a small torque transmission ball is used, the thickness of the cage column is insufficient. It leads to strength reduction. However, in this invention, since the inner diameter of the axial center part of the cage is made the same as the inner diameter of the end part and the inner peripheral surface of the cage is cylindrical, the lack of strength can be compensated.

  In the present invention, when it is limited to a constant velocity universal joint used for a drive shaft of an automobile, the intersection angle of the ball grooves is 10 ° or more and 15 ° or less, and the number of torque transmitting balls can be 10. Further, when it is limited to a constant velocity universal joint used for a propeller shaft of an automobile, the intersection angle of the ball grooves can be 6 ° or more and 9 ° or less, and the number of torque transmitting balls can be 10. The angle of intersection of the ball grooves is the angle of intersection between the ball grooves of the inner ring and the ball grooves of the outer ring, which are inclined in opposite directions, with the axis of the inner ring or the outer ring, respectively.

  In the cross groove type constant velocity universal joint used for the drive shaft, the maximum operating angle of the joint is not reduced by setting the intersection angle of the ball grooves to 10 ° or more and 15 ° or less and the number of torque transmitting balls to 10, Moreover, a sliding stroke can be earned. Similarly, in a cross groove type universal joint used for a propeller shaft, the maximum operating angle of the joint is not reduced by setting the cross angle of the ball groove to 6 ° to 9 ° and the number of torque transmitting balls to 10. Also, you can earn sliding strokes. When the number of torque transmitting balls is 10, even if the wedge angle is reduced, the driving force of the torque transmitting ball whose wedge angle is reversed is shared by other torque transmitting balls to drive the cage. It can be stabilized.

  The cross groove type universal joint of the present invention includes an inner ring having an outer peripheral surface in which ball grooves inclined in opposite directions with respect to an axis are alternately formed in a circumferential direction, and a ball groove inclined in directions opposite to each other with respect to an axis. An outer ring having inner circumferential surfaces alternately formed in the circumferential direction, a torque transmission ball incorporated at the intersection of an inner ring ball groove and an outer ring ball groove inclined in opposite directions with respect to the axis, and an inner ring A cage that is interposed between the outer peripheral surface and the inner peripheral surface of the outer ring and holds the torque transmission balls at a predetermined interval in the circumferential direction. Since the inner diameter surface of the cage is cylindrical, the radial thickness of the pillar portion, which is the portion between the pockets for accommodating the torque transmission balls in the cage, increases, and the strength of the pillar portion is improved. be able to. For this reason, even when an excessive torque is input to the joint, the pillar portion of the cage can be prevented from being damaged.

  A first embodiment of the present invention will be described with reference to FIGS. This cross groove type constant velocity universal joint includes an inner ring 2, an outer ring 4, six torque transmission balls 6, and a cage 8 as main components.

  The inner ring 2 is ring-shaped and has ball grooves 2a and 2b formed on the outer peripheral surface. Similarly, the outer ring 4 is also ring-shaped and has ball grooves 4a and 4b formed on the inner peripheral surface thereof. FIG. 3 is a developed view of the ball groove. As shown by the solid line in FIG. 3, the ball grooves 2a and 2b inclined in opposite directions with respect to the axis of the inner ring 2 are alternately positioned in the circumferential direction. . Further, as indicated by a two-dot chain line, ball grooves 4 a and 4 b inclined in opposite directions with respect to the axis of the outer ring 4 are alternately positioned in the circumferential direction.

  The crossing angle of each ball groove 2a, 2b, 4a, 4b with respect to the axis is represented by the symbol β. The ball groove 2a (or ball groove 2b) of the inner ring 2 and the ball groove 4a (or ball groove 4b) of the outer ring 4 which are inclined in opposite directions form a pair, and the crossing angle (wedge angle) of both is represented by 2β. The

  A torque transmitting ball 6 is incorporated at the intersection of the ball groove 2a and the ball groove 4a or the ball groove 2b and the ball groove 4b forming a pair. As shown in FIG. 4, here, there are six ball grooves 2 a and 2 b of the inner ring 2, six ball grooves 4 a and 4 b of the outer ring, and six torque transmission balls 6.

  As shown in FIG. 5, the ball grooves 2a, 2b, 4a, 4b of the inner ring 2 and the outer ring 4 generally have a Gothic arch or elliptical cross-sectional shape, and the torque transmission ball 6 and the ball grooves 2a, 2b, 4a. , 4b is an angular contact. For example, the contact angle α of the angular contact is in the range of 30 to 50 °.

  As shown in FIG. 6, the cage 8 is formed with the same number of window-like pockets 8 a that accommodate and hold the torque transmission balls 6 as the number of torque transmission balls 6 at equal intervals in the circumferential direction. A portion between adjacent pockets is a column portion 8b. The outer peripheral surface 8 c of the cage 8 is spherical, and the inner peripheral surface of the outer ring 4 is a guide surface for the outer peripheral surface 8 c of the cage 8. Moreover, the inner peripheral surface 8d of the cage 8 is cylindrical, and the central portion and the end portion thereof in the axial direction have the same inner diameter. Therefore, the radial thickness of the column portion 8b is greatest at the axially central portion. The central portion in the axial direction is a portion where the circumferential width of the column portion 8b is the smallest. That is, by increasing the thickness of the narrow portion, the portion having low strength is partially eliminated, and the strength of the entire column portion 8b is improved. Thereby, it is possible to prevent the column portion 8b of the cage 8 from being damaged when an excessive torque is input to the joint.

  When an external force is applied to the cross-groove type constant velocity universal joint, torque is transmitted by the action of the wedge angle 2β formed at the intersection of the paired inner ring ball grooves 2a, 2b and the outer ring ball grooves 4a, 4b. The ball 6 is pushed to the end face of the pocket 8 a of the cage 8. As a result, the torque transmitting ball 6 is always held at the intersection of the ball grooves, and even when an angular displacement occurs between the inner and outer rings 2, 4, the operating angle (relative angle between the inner ring 2 and the outer ring 4) is always equal. Maintained within the dividing plane. As described above, the cross groove type constant velocity universal joint has a constant velocity and is excellent with little backlash.

  7 and 8 show an inner ring / outer ring and a cage according to the second embodiment of the present invention. The difference between this embodiment and the first embodiment is the number of torque transmission balls. Basically, except for the inner and outer rings and the cage, which are clearly different from the first embodiment in relation to this, The same structure as the first embodiment. For this reason, the figures corresponding to FIGS. 1, 2, 3 and 5 in the first embodiment are omitted, and the explanation related thereto is also omitted.

  In this embodiment, the number of torque transmission balls 6 is 8, and eight ball grooves 2a, 2b, 4a, 4b are formed in the inner ring 2 and the outer ring 4, respectively. The cage 8 has pockets 8a at eight locations. As in the first embodiment, the inner peripheral surface 8d of the cage 8 is cylindrical, and the central portion and the end portion thereof in the axial direction have the same inner diameter. Thereby, the strength improvement of the pillar part 8b which is a site | part between adjacent pockets is aimed at.

  In the case of this embodiment, the following conditions are defined in relation to the number of torque transmission balls 6 being eight. That is, the crossing angle β (see FIG. 3) with respect to the axis of the ball grooves 2a, 2b, 4a, 4b is set to 4.5 ° or more and 8.5 ° or less. The basis for this is shown below.

  Cross groove type constant velocity universal joints have a much larger operating angle than constant velocity universal joints that control torque transmitting balls by offsetting the center of the arc-shaped ball groove formed in the axial direction on the inner and outer rings. It is said that it cannot be taken. This is because if the operating angle is increased, the wedge angle 2β, which is the intersection angle of the ball grooves of the inner and outer rings, is reversed, and the balance of the force acting on the cage from the torque transmitting ball is lost. As a result, the cage becomes unstable because it cannot balance the force.

  It is conceivable to prevent the wedge angle 2β from being reversed by increasing the crossing angle β of the ball grooves of the inner and outer rings. However, since the inner ring and the outer ring are alternately arranged in the circumferential direction with ball grooves inclined in opposite directions with respect to the axis, it is necessary to avoid interference between adjacent ball grooves. There is a limit to increasing the size.

  The wedge angle 2β is also related to the sliding stroke of the joint, and it is effective to reduce the wedge angle 2β in order to increase the stroke amount. However, if the crossing angle β of the ball groove with respect to the axis is reduced in order to increase the sliding stroke of the joint, the maximum operating angle as a constant velocity universal joint is reduced. The maximum operating angle is an angle at which a maximum torque appears when an operation of bending and returning the joint is performed without rotating. In the worst case, there is a phenomenon that the angle does not return, that is, it is caught.

  For the above reasons, it has been generally considered that the cross groove type constant velocity universal joint has a small degree of freedom in the maximum operating angle and the sliding amount. In order to expand the application of cross groove type constant velocity universal joints and operate properly when applied to various machines, it is necessary to earn a sliding stroke without reducing the maximum operating angle.

  By making the crossing angle of the ball groove with respect to the axis line 4.5 ° or more and 8.5 ° or less and the number of the torque transmitting balls 8, the maximum operating angle of the joint will not be reduced and the sliding stroke will be increased. Can do. As already mentioned, in a cross groove type constant velocity universal joint, there is a torque transmission ball at a certain phase, and when the operating angle is increased, the wedge angle is reversed, and the balance of the force acting on the cage from the torque transmission ball is reversed. Collapses and the drive of the cage becomes unstable. As the wedge angle becomes smaller, this phenomenon becomes prominent when the number of torque transmitting balls is up to six. However, by setting the number of torque transmitting balls to 8 or more, even if the wedge angle is reduced, the drive of the cage is stabilized up to a certain value. This is because the driving force of the torque transmission ball whose wedge angle has been reversed is shared by other torque transmission balls to stabilize the driving of the cage.

  9 and 10 show an inner ring / outer ring and a cage according to the third embodiment of the present invention. The difference between this embodiment and the first embodiment is also the number of torque transmission balls, and the basic elements other than the inner ring / outer ring and the cage are clearly different from those of the first embodiment. The same structure as the first embodiment. For this reason, the figures corresponding to FIGS. 1, 2, 3 and 5 in the first embodiment are omitted, and the explanation related thereto is also omitted.

  In this embodiment, the number of torque transmission balls 6 is 10, and 10 ball grooves 2a, 2b, 4a, 4b are formed in the inner ring 2 and the outer ring 4, respectively. The cage 8 is formed with pockets 8a at ten locations. Similar to the first and second embodiments, the inner peripheral surface 8d of the cage 8 is cylindrical, and the central portion and the end portion thereof in the axial direction have the same inner diameter. Thereby, the strength improvement of the pillar part 8b which is a site | part between adjacent pockets is aimed at.

  In the case of this embodiment, the following conditions are defined in relation to the number of torque transmission balls 6 being ten. That is, in the case of a cross groove type constant velocity universal joint used for a drive shaft, the crossing angle β (see FIG. 3) with respect to the axis of the ball grooves 2a, 2b, 4a, 4b is set to 10 ° to 15 °. Further, in the case of a cross groove type constant velocity universal joint used for a propeller shaft, the crossing angle β (see FIG. 3) with respect to the axis of the ball grooves 2a, 2b, 4a, 4b is 6 ° or more and 9 ° or less. The basis for this is shown below.

  The cross-groove type constant velocity universal joint has a low degree of freedom in the maximum operating angle and sliding amount, as described above. This is a problem when the cross groove type constant velocity universal joint is assembled to an automobile. Become. In other words, when assembling a cross groove type constant velocity universal joint to an automobile, it is necessary to first fold the joint and then return it to its original position. However, if the maximum operating angle is small, the above phenomenon occurs when the joint is bent. It is easy and the workability of the assembly work is very bad.

  For this reason, even if the crossing angle of the ball groove is reduced to increase the sliding stroke, the maximum operating angle is not reduced, and excellent folding characteristics with little catching during folding can be obtained, and assembly workability when assembling the vehicle is improved. A cross groove type constant velocity universal joint for a drive shaft and a propeller shaft that can be improved is desired.

  In the cross groove type constant velocity universal joint used for the drive shaft, the maximum operating angle of the joint is not reduced by setting the intersection angle of the ball grooves to 10 ° or more and 15 ° or less and the number of torque transmitting balls to 10, Moreover, a sliding stroke can be earned. Similarly, in a cross groove type universal joint used for a propeller shaft, the maximum operating angle of the joint is not reduced by setting the cross angle of the ball groove to 6 ° to 9 ° and the number of torque transmitting balls to 10. Also, you can earn sliding strokes.

  The required operating angle of the cross groove type constant velocity universal joint used for the drive shaft is about 20 °. As a result of analyzing the operating angle up to 25 °, the crossing angle of the ball groove is 10 ° or more. If it exists, it was confirmed that the conventional torque transmission ball | bowl is excellent in a bending characteristic rather than the thing of six types.

  Similarly, in the cross groove type constant velocity universal joint used for the propeller shaft, the required operating angle is about 10 °. As a result of analyzing the operating angle up to 15 °, the intersection angle of the ball grooves is 5 If it is more than 0 °, it has been confirmed that the conventional torque transmission balls have better bending characteristics than those of the six types.

  Thus, even if the crossing angle of the ball grooves is reduced to increase the sliding stroke, the maximum operating angle is not reduced, and excellent bending characteristics with little catching during bending can be obtained. Therefore, the assembly workability at the time of vehicle assembly can be improved.

1 is a partially cutaway perspective view of a cross groove type constant velocity universal joint according to a first embodiment of the present invention. It is sectional drawing of the cross groove type constant velocity universal joint. It is an expanded view of the ball groove of the cross groove type constant velocity universal joint. It is a front view of the inner ring and outer ring of the cross groove type constant velocity universal joint. It is sectional drawing of the ball groove of the cross groove type constant velocity universal joint. (A) of the cross groove type constant velocity universal joint is a front view of the cage, and (b) is a VIb-VIb sectional view thereof. It is a front view of the inner ring | wheel and outer ring | wheel of the cross groove type constant velocity universal joint concerning 2nd Embodiment of this invention. (A) of the cross-groove type constant velocity universal joint is a front view of the cage, and (b) is a sectional view taken along the line VIIIb-VIIIb. It is a front view of the inner ring | wheel and outer ring | wheel of the cross groove type constant velocity universal joint concerning 3rd Embodiment of this invention. (A) of the cross groove type constant velocity universal joint is a front view of the cage, and (b) is an Xb-Xb sectional view thereof. (A) of the conventional cross groove type constant velocity universal joint is a front view of a cage, (b) is the XIb-XIb sectional drawing. (A) of the different conventional cross groove type constant velocity universal joint is a front view of a cage, (b) is the XIIb-XIIb sectional drawing.

Explanation of symbols

2 ... Inner rings 2a, 2b ... Ball groove 4 ... Outer rings 4a, 4b ... Ball groove 6 ... Torque transmission ball 8 ... Cage 8a ... Pocket 8b ... Column

Claims (4)

  An inner ring having an outer peripheral surface alternately formed in the circumferential direction with ball grooves inclined in opposite directions with respect to the axis, and an inner ring having ball grooves inclined in the opposite directions with respect to the axis in the circumferential direction. An outer ring having a peripheral surface, a torque transmitting ball incorporated at the intersection of the ball groove of the inner ring and the ball groove of the outer ring inclined in opposite directions with respect to the axis, and the outer peripheral surface of the inner ring and the inner peripheral surface of the outer ring. And a cage for holding the torque transmission balls at a predetermined interval in the circumferential direction, the inner diameter of the axial central portion of the cage being the same as the inner diameter of the end, and the inner circumferential surface of the cage A cross-groove type constant velocity universal joint characterized by having a cylindrical shape.   2. The number of torque transmitting balls according to claim 1, wherein the inner ring ball groove and the outer ring ball groove inclined in opposite directions have an intersection angle of 4.5 ° or more and 8.5 ° or less with the axis of the inner ring or outer ring, respectively. Is a cross groove type constant velocity universal joint.   2. The constant velocity universal joint used in a drive shaft of an automobile according to claim 1, wherein the inner ring ball groove and the outer ring ball groove inclined in opposite directions have an intersection angle of 10 ° with the axis of the inner ring or the outer ring, respectively. A cross groove type constant velocity universal joint in which the number of torque transmitting balls is 10 and 15 degrees or less.   2. The constant velocity universal joint used in a propeller shaft of an automobile according to claim 1, wherein the inner ring ball groove and the outer ring ball groove, which are inclined in opposite directions, each have an intersection angle of 6 ° with the axis of the inner ring or the outer ring. A cross groove type constant velocity universal joint in which the number of the torque transmission balls is 10 and 9 degrees or less.

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