JP2006316898A - Fixed type constant velocity universal joint - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fixed type constant velocity universal joint capable of achieving an operation angle than higher a conventional operation angle by bringing out a ball to the outer side of an outer side joint member without dropping it. <P>SOLUTION: In this Rzeppa universal joint, ball center loci C1, C2 of two guide channels 1b, 2b of the outer side joint member 1 and an inner side joint member 2 are formed into common circular arcs in which they are mutually overlapped in a part except central parts in the axial direction of the joint of the guide channels 1b, 2b, and the central parts in the axial direction of the joint of the guide channels 1b, 2b are eccentric with respect to an inner side in the radial direction from the common circular arc in such a way that they cross mutually and become mirror-image symmetrical in the axial direction across the center of the joint (inclined straight lines bc, fg). <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The fixed type constant velocity universal joint of the present invention connects the drive side rotary shaft and the driven side rotary shaft so that torque can be transmitted at an equal angular speed even when both shafts are angled. It can only be angularly displaced without being used, and is used as a fixed constant velocity universal joint for power transmission of various industrial machines including automobiles.

 A fixed type constant velocity universal joint is generally used for an axle connecting portion of a drive shaft of an automobile and a shaft bending connecting portion of a steering shaft. As this fixed type constant velocity universal joint, conventionally, a zepper type constant velocity universal joint and an undercut free type (hereinafter referred to as UJ type) constant velocity universal joint are known. The Zeppa type feature is that the ball center trajectory of the guide groove of the outer joint member and the ball center trajectory of the guide groove of the inner joint member are two spheres centered at a point equidistant from the joint center in the ring direction. It is a meridian. (See Patent Document 1).

 On the other hand, the UJ type constant velocity universal joint was invented to have a higher operating angle than the Zepper type constant velocity universal joint, and the ball center locus of the guide groove of the outer joint member is the above-mentioned Zepper type meridian. Among the arcs, the opening side portion of the outer joint member is a straight line parallel to the joint axis from the cross section perpendicular to the axis passing through the joint center. (See Patent Document 2)

 The Zepper type constant velocity universal joint invented by Zeppa initially has the same arc with the center of the ball of the guide groove of the outer joint member and the center of the ball of the guide groove of the inner joint member centered on the joint center. there were. (See Patent Document 3). The universal joint has a drawback that the rotational position of the cage at an operating angle of 0 ° is not fixed, and in order to compensate for this, the position of the cage is controlled between the inner joint member and the outer joint member. Another part was added (refer to Fig. 1 and Fig. 2 pilot pin K of Patent Document 4).

 The zeppa type constant velocity universal joint improved thereafter is a so-called double offset type. As shown in FIGS. 5A and 6, the two guide grooves 1b and 2b of the outer joint member 1 and the inner joint member 2 are used. The ball center trajectories C1 and C2 are circles having the same radius R centered on points A and B that are separated from the joint center O by an equal distance in the opposite direction to the joint axial direction. Specifically, as shown in FIG. 5, the double offset type constant velocity universal joint includes an outer joint member 1 in which six curved guide grooves 1b are formed in an axial direction on a spherical inner peripheral surface 1a, and a spherical shape. Six curved guide grooves 2b are formed in the outer peripheral surface 2a in the axial direction, and the inner joint member 2 having spline (or serration) holes 2c, the guide groove 1b of the outer joint member 1, and the guide of the inner joint member 2 are provided. The groove 2b is composed of a torque transmission ball 3 arranged one by one on six ball tracks formed in cooperation with each other, and a cage 4 for holding the torque transmission ball 3.

  The center of curvature of the inner peripheral surface 1a of the outer joint member 1 and the center of curvature of the outer peripheral surface 2a of the inner joint member 2 are all coincident with the joint center O. The center of curvature A of the guide groove 1b of the outer joint member 1 and the center of curvature B of the guide groove 2b of the inner joint member 2 are opposite to each other by an equal distance in the axial direction across the joint center O (in the example shown in the figure). Center A is offset on the opening side of the joint, and center B is offset on the back side of the joint. Therefore, the ball track formed by the cooperation of the guide grooves 1b and 2b has a wedge that opens toward one side in the axial direction (in the example shown in the figure, considering the assembly of the joint). It has a shape.

  As shown in FIG. 5A, when the two axes are not angularly displaced, that is, in a state where the rotation axes of the two axes are in a straight line, the center of all the torque transmission balls 3 includes the joint center O and is a plane perpendicular to the rotation axis. Is in. When the outer joint member 1 and the inner joint member 2 are angularly displaced by an angle θ, the cage 4 causes the torque transmission ball 3 to be oriented in a plane that bisects the angle θ, thereby making the joint constant velocity. Secured.

 In this double offset type constant velocity universal joint, when the joint is rotated at a high operating angle, if the ball 3 protrudes outward from the guide groove 1 b of the outer joint member 1, the ball 3 is radially outward from the window of the cage 4. I can't prevent you from jumping out. For this reason, in the conventional double offset type constant velocity universal joint, the ball 3 must be stored in the guide groove 1b of the outer joint member 1, thereby suppressing the maximum operating angle of the joint, and at most 48 °. The degree was the limit.

 On the other hand, the UJ type constant velocity universal joint was invented to further expand the operating angle of the Zepper type constant velocity universal joint, and in order to extend the position where the ball comes off the guide groove of the outer joint member, The ball center locus of the guide groove of the member was changed from an arc shape to a linear shape only for the outer joint member-containing portion. However, the maximum operating angle of the UJ type constant velocity universal joint was about 52 °.

 In order to further increase the operating angle of the joint, for example, about 60 °, the ball must be taken out from the guide groove of the outer joint member. At this time, if the ball guide surface of the cage is a flat surface, the ball falls out from the window of the cage, and the constant velocity universal joint loses its function.

US Patent No. 2046584 JP-A-53-65547 U.S. Pat. No. 1,665,280 US Patent No. 2010899

  An object of the present invention is to provide a fixed type constant velocity universal joint capable of realizing a higher operating angle than the conventional one by taking out the ball to the outside of the outer joint member without dropping off.

  In order to solve the above problems, the invention of claim 1 is directed to an outer joint member in which a plurality of guide grooves extending in the axial direction are formed on a spherical inner peripheral surface, and a plurality of guides extending in the axial direction on a spherical outer peripheral surface. An inner joint member formed with a groove, a torque transmission ball disposed on each of a plurality of ball tracks formed in cooperation with a guide groove of the outer joint member and a guide groove of the inner joint member, and a torque transmission ball And the ball center locus of the two guide grooves of the outer joint member and the inner joint member into a common arc overlapping each other around the joint center in the portion excluding the joint axial direction center portion of the guide groove. In addition, the joint axial center portion of the guide groove is biased radially inward from the common arc so as to cross each other and be mirror-image symmetric in the axial direction across the joint center.

 In the constant velocity universal joint of the present invention, when the joint is bent by approximately 10 ° or more, the ball center trajectories of the two guide grooves of the outer joint member and the inner joint member are both the same circle (circular arc) centered on the joint center. ) Therefore, even when a large operating angle is taken, since the center position of the ball is not separated from the joint center, there is no need to extend the guide groove of the outer joint member long to the opening side, and therefore the shaft connected to the inner joint member. It is possible to increase the operating angle that interferes with the outer joint member. In addition, at a high operating angle exceeding 50 ° and approaching 60 °, some of the balls come out from the guide groove of the outer joint member. By making it narrower, the ball can be held in the guide groove side of the inner joint member by the cage even on the outer side of the outer joint member, and the ball can be prevented from falling off the cage.

 On the other hand, according to the present invention, the joint shaft of the guide groove is formed so that the joint axial direction central portions of the two guide grooves of the outer joint member and the inner joint member cross each other and are mirror-image symmetrical in the axial direction across the joint center. Since the common arcs that overlap each other in the portion excluding the central portion in the direction are biased radially inward, the ball can be held in the cross-section, that is, the axial center cross section of the joint center. By holding, the cage can be held in a cross section perpendicular to the axis of the joint center at a joint operating angle of 0 °.

The invention of claim 2 is characterized in that, in the invention of claim 1, the ball track is formed in a wedge shape which opens toward the joint opening side.
As a result, the fixed type constant velocity universal joint can be easily assembled, that is, the workability when the inner joint member and the cage are assembled inside the outer joint member is improved, and the shaft connected to the inner joint member is connected to the outer joint member. The operating angle that interferes with can be increased.

The invention of claim 3 is characterized in that, in the invention of claim 1, the center line of the ball at the center of the guide groove is an arc.
By configuring the ball center line at the center portion of the guide groove with an arc, the ball can smoothly roll when the joint takes an operating angle.

The invention of claim 4 is characterized in that, in the invention of claim 1, the center line of the ball at the center of the guide groove is a straight line.
By forming the ball center line at the center of the guide groove with a straight line, the guide groove can be easily processed. In addition, by smoothly connecting both ends of the “straight line” to the common arc, it is possible to smoothly roll the ball when the joint takes an operating angle.

According to a fifth aspect of the present invention, in the first aspect of the present invention, the ball guide surfaces, which are the inner surfaces of the cage and are opposed to each other in the axial direction of the joint, are made parallel planes on the inner diameter side and the balls are held on the outer diameter side. It is characterized by narrowing inward.
As a result, even when some balls come out from the guide groove of the outer joint member at the high operating angle of the joint, the balls can be held by the cage on the guide groove side of the inner joint member, and the balls are retained. Can be prevented from falling out of the vessel.

 According to a sixth aspect of the present invention, in the first or fifth aspect of the present invention, the inner diameter surface of the cage on the joint opening side is a cylindrical surface, and the spherical outer peripheral surface of the inner joint member is slidably guided to the cylindrical surface. And a retaining ring for retaining the guide ring.

  When the ball guide surface of the cage is narrowed inward on the outer diameter side, the ball cannot be inserted into the window from the outer diameter side of the cage during assembly of the joint. The ball is inserted into the window from the inner diameter side of the cage. Then, the inner joint member must be inserted into the cage from the joint opening side, so the inner diameter surface of the cage on the joint opening side is a cylindrical surface. It is necessary to keep. If this cylindrical surface is left as it is, it will not prevent the inner joint member from being removed, so the inner joint member is prevented from being removed by the guide ring and the retaining ring.

 The invention according to claim 7 is the invention according to claim 1, wherein only a part of the plurality of ball tracks of the plurality of ball tracks, the ball center locus of the inner and outer two guide grooves is a portion excluding the central portion in the joint axial direction of the guide grooves. And the joint axial center portions of the guide grooves are biased radially inward from the common arc so as to cross each other and be mirror-symmetric in the axial direction across the joint center. The ball track is characterized in that the ball center locus of the two inner and outer guide grooves is a single circular arc that overlaps the whole.

That is, the number of ball tracks is usually 6 or 8 or more, but for example only 3 or 4 ball tracks (ie every other ball track), the ball center trajectory is as in claim 1 and the rest In this ball track, the ball center trajectories of the inner and outer guide grooves are formed as a single circular arc that overlaps the whole.
As a result, the cage can be held in a cross section perpendicular to the axis of the joint center at a joint operating angle of 0 °, and the transmittable torque can be further increased.

 In the present invention, since the center position of the ball is not separated from the joint center even when a high operating angle is taken, it is not necessary to extend the guide groove of the outer joint member long to the opening side, and therefore the ball is connected to the inner joint member. The operating angle at which the shaft interferes with the outer joint member can be increased. Also, for example, at a high operating angle that exceeds 50 ° and approaches 60 °, some of the balls come out from the guide groove of the outer joint member. By making it smaller than the diameter, the ball can be held by the cage on the guide groove side of the inner joint member outside the outer joint member, and the ball will not fall out of the cage.

 On the other hand, in the present invention, the joint axial direction of the guide groove is such that the joint axial direction central portions of the two guide grooves of the outer joint member and the inner joint member intersect each other and are mirror-image symmetrical in the axial direction across the joint center. Since the common arcs that overlap each other in the portion other than the central portion are biased radially inward, the ball can be held in the crossing portion, that is, in the cross-section perpendicular to the axis of the joint center. The cage can be held in a cross section perpendicular to the axis of the joint center at a joint operating angle of 0 °.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS. 1A and 1B show a fixed type (zeppa type) constant velocity universal joint according to the present invention, where FIG. 1A shows a state where the operating angle is 0 ° and FIG. . The constituent members of the constant velocity universal joint are basically the same as those of the constant velocity universal joint of FIG. 5, and the same portions are denoted by the same reference numerals and redundant description is omitted.

 The constant velocity universal joint is characterized by the ball center loci C1 and C2 of the two guide grooves 1b and 2b of the outer joint member 1 and the inner joint member 2. That is, as shown in FIG. 2A, the ball center locus C1 of the guide groove 1b of the outer joint member 1 is basically a circle (arc abcd) having a radius R centered on the joint center O. The point a corresponds to the entrance of the guide groove 1b of the outer joint member 1, and the point d corresponds to the back part. As shown in FIG. 2B, the ball center locus C2 of the guide groove 2b of the inner joint member 2 is also basically a circle (arc efgh) having a radius R centered on the joint center O. Thus, since the two circles or trajectories C1 and C2 have the same center and the same radius, when the two ball center trajectories C1 and C2 are overlapped, the axis of the joint center O as shown in FIG. Except for the cross section at right angles, they overlap completely.

 Further, in the two circles, that is, the trajectories C1 and C2, the vicinity of the cross section perpendicular to the axis of the joint center O deviates from the circle and is biased inward. In the illustrated example, the ball center locus C1 of the outer joint member 1 is an inclined straight line cb near the cross section perpendicular to the axis, and the ball center locus C2 of the inner joint member 2 is an inclined straight line fg near the cross section perpendicular to the axis. When the two ball center loci C1 and C2 are overlapped as shown in FIG. 2C, the inclined straight line cb and the inclined straight line fg are mirror-image-symmetrical on the left and right with respect to the cross section perpendicular to the axis. fg crosses symmetrically in the cross section perpendicular to the axis in the inner region of the circle, and the distance from the cross section perpendicular to the axis is equal for b and g, and is equal for c and f.

  As shown in FIG. 3, the inner diameter surface on the joint opening side of the cage 4 is a cylindrical surface having a constant inner diameter over a predetermined width, and a retaining ring 5 (circlip) is fitted into a groove portion 4 a formed on the cylindrical surface. . The guide ring 6 is fitted into a narrow annular wedge space formed inside the retaining ring 5 and between the retainer 4 and the window 4b. The guide ring 6 has an inner peripheral surface fitted to the spherical outer peripheral surface 2 a of the inner joint member 2 and an outer peripheral surface fitted to the spherical inner peripheral surface 4 c of the cage 4. Further, the outer end of the guide ring 6 comes into contact with the inner surface of the retaining ring 5. A certain gap is secured between the inner end of the guide ring 4 and the ball 3.

  The ball guide surface of the window 4b of the cage 4 has a narrow outer diameter side as shown in FIG. In other words, the inner diameter side of the ball guide surface is parallel straight 4b1 with an interval equal to the ball diameter, but the outer diameter side of the ball guide surface is tapered so as to be slightly narrower than the ball diameter. It has become. This tapered portion may be formed by an inclined straight line, but in order to reduce the contact surface pressure with the ball, it is preferable to have a concave arc shape 4b2 that matches the outer peripheral curvature of the ball.

  The fixed type constant velocity universal joint according to the present invention is configured as described above, and when the joint is bent by approximately 10 ° or more, the ball center locus C1 of the two guide grooves 1b and 2b of the outer joint member 1 and the inner joint member 2 is obtained. , C2 are all the same circle (arc) centered on the joint center. Therefore, even when a large operating angle is taken, since the center position of the ball 3 is not separated from the joint center, it is not necessary to extend the guide groove 1b of the outer joint member 1 to the opening side long, and therefore the inner joint member 2 The operating angle at which the shaft 7 coupled to the outer joint member 1 interferes can be increased. Further, for example, at a high operating angle exceeding 50 ° and approaching 60 °, a part of the balls 3 comes out from the guide groove 1b of the outer joint member 1, but the ball guide surface on the outer diameter side of the cage 4 By making the facing interval smaller than the ball diameter, the ball 3 can be held on the guide groove 2b side of the inner joint member 2 by the cage 4 even on the outer side of the outer joint member 1. Can be prevented from falling off the cage 4.

 Further, as shown in FIG. 2C, the joint axial center portions of the two guide grooves 1b and 2b of the outer joint member 1 and the inner joint member 2 cross each other and are mirror-image-symmetric in the axial direction with the joint center O interposed therebetween. Since the common arcs cd and ef that overlap each other in the portion excluding the joint axial direction center portion of the guide grooves 1b and 2b are biased radially inward so that the ball 3 is in the intersection portion, that is, the joint center O. It can hold | maintain in a cross section orthogonal to an axis | shaft, and the retainer 4 can be hold | maintained in the cross section perpendicular to the axis | shaft of the joint center O at the joint operating angle of 0 degree by holding | maintaining the fixed position of such a ball | bowl 3.

  As mentioned above, although one embodiment of the present invention has been described, the present invention is not limited to the above-described embodiment, and various modifications are possible. For example, in the above-described embodiment, the cross-section perpendicular to the joint axis of the ball center loci C1 and C2 The portions that are biased inward in the radial direction are inclined straight lines bc and fg. However, since these portions should be mirror-symmetrical and biased inward, the radius of curvature is greater than R instead of the tilted straight lines bc and fg. You may connect smoothly to the point b, c thru | or the point f, g with a big circular arc other curve.

(A) (B) is sectional drawing of the fixed type constant velocity universal joint which concerns on this invention. The ball center locus of the guide groove is exaggeratedly shown, (A) is the ball center locus of the guide groove of the outer joint member, (B) is the ball center locus of the guide groove of the inner joint member, and (C) is the outer joint. The ball center locus where two guide grooves of the member and the inner joint member overlap each other. The expanded sectional view of the ball | bowl part of a holder | retainer. The expanded sectional view which exaggerates and shows the ball guide surface shape of the window of a holder. (A) is a longitudinal cross-sectional view of a conventional zeppa type constant velocity universal joint, and (B) is a cross-sectional view of the same. A ball center locus of two guide grooves of an outer joint member and an inner joint member of a conventional zepper type constant velocity universal joint.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Outer joint member 1a Spherical inner peripheral surface 1b, 2b Guide groove 2 Inner joint member 2a Spherical outer peripheral surface 2c Spline hole 3 Torque transmission ball 4 Cage 4a Groove 4b Window 4c Spherical inner peripheral surface 5 Retaining ring 6 Guide ring 7 Shaft C1, C2 Ball center locus

Claims (7)

 An outer joint member having a plurality of guide grooves extending in the axial direction on a spherical inner peripheral surface, an inner joint member having a plurality of guide grooves extending in the axial direction on a spherical outer peripheral surface, and guiding of the outer joint member A torque transmission ball disposed on each of a plurality of ball tracks formed in cooperation with the groove and the guide groove of the inner joint member, and a cage for holding the torque transmission ball, The ball center locus of the two guide grooves of the joint member is a common arc that overlaps each other around the joint center except for the joint axial center part of the guide groove, and the joint axial center part of the guide groove is mutually A fixed type constant velocity universal joint characterized in that it is deviated radially inward from the common arc so as to cross and have a mirror image symmetry in the axial direction across the joint center.   2. The fixed type constant velocity universal joint according to claim 1, wherein the ball track has a wedge shape opened toward the joint opening side.  2. The fixed type constant velocity universal joint according to claim 1, wherein the center line of the ball at the center of the guide groove is an arc.  2. The fixed type constant velocity universal joint according to claim 1, wherein the ball center line at the center of the guide groove is a straight line.  2. A ball guide surface, which is an inner surface of a cage and is opposed to each other in the axial direction of the joint, is formed into a parallel plane on the inner diameter side and narrowed inward so as to embrace the ball on the outer diameter side. Fixed type constant velocity universal joint.  The inner diameter surface of the cage on the joint opening side is made a cylindrical surface, and a guide ring for slidingly guiding the spherical outer peripheral surface of the inner joint member to this cylindrical surface and a retaining ring for retaining the guide ring are mounted. The fixed type constant velocity universal joint according to claim 1 or 5, wherein the fixed type constant velocity universal joint is provided.  Of the plurality of ball tracks, only a part of the ball tracks have a ball center locus of the inner and outer guide grooves that is a common arc that overlaps with each other except the central portion of the guide groove in the joint axial direction, and the joint shaft of the guide groove. The central portion in the direction is biased radially inward from the common arc so as to cross each other and be mirror-symmetric in the axial direction across the joint center, and in the remaining ball tracks, the ball center trajectories of the two inner and outer guide grooves are 2. The fixed type constant velocity universal joint according to claim 1, wherein the entire arc is a single arc.

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