JP2008039077A - 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 realizing an operating angle wider than a conventional one. <P>SOLUTION: A joint opening end of a guide groove 1b of an outside joint member 1 is used as a guide section 1c opened radially outwardly. The guide section 1c can return a ball 4 coming out of the guide groove 1b of the outside joint member 1 to the guide groove 1b smoothly. Since interference between the ball 4 and the outside joint member 1 is thus avoided, the joint can be operated smoothly even if a large operating angle is set. <P>COPYRIGHT: (C)2008,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.

  In the Zepper type constant velocity universal joint invented by Zepper, initially, the ball center locus of the guide groove of the outer joint member and the ball center locus of the guide groove of the inner joint member are both the same arc centered on the joint center. (See Patent Document 1). The Zeppa type constant velocity universal joint improved thereafter is a so-called double offset type, and the ball center trajectories of the two guide grooves of the outer joint member and the inner joint member are respectively equal to the joint axis direction opposite from the joint center. A circle with the same radius centered on a point separated by a distance is used (see Patent Document 2).

  In this double offset type constant velocity universal joint, when the joint is rotated at a high operating angle, if the ball protrudes outward from the guide groove of the outer joint member, the ball jumps radially outward from the cage window. Can not be prevented. For this reason, in the conventional double offset type constant velocity universal joint, the ball must be stored in the guide groove of the outer joint member. This limits the limit operating angle of the joint, which is at most about 48 °. It was.

  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 circular arcs, a portion on the opening side of the outer joint member from a cross section perpendicular to the axis passing through the joint center is a straight line parallel to the joint axis (see Patent Document 3). However, the limit operating angle of this UJ type constant velocity universal joint was about 52 °.

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

  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 that time, in the constant velocity universal joint as described above, if the ball is taken out from the guide groove of the outer joint member without taking any measures, the ball may drop off. In order to prevent such a problem, the present applicant has proposed a constant velocity universal joint having the following configuration in the previous application.

  For example, in the constant velocity universal joint of Japanese Patent Application No. 2005-140162, the joint back side portion of the guide groove of the inner joint member is an arc having the joint center as the center of curvature. As a result, even when a large operating angle is taken, the center position of the ball is not separated from the center of the joint, so even if the ball goes out of the guide groove of the outer joint member, the cage and the guide groove of the inner joint member Can be held in between.

  Further, in the constant velocity universal joint of Japanese Patent Application No. 2005-162969, the outer side window opening dimension of the cage window that accommodates the ball is made smaller than the diameter of the ball. Thereby, even if it is the outer side of an outer joint member, since a ball | bowl can be held by the guide groove side of an inner joint member with a holder | retainer, it can prevent that a ball | bowl falls from a holder | retainer.

  In this way, in the constant velocity universal joint that can protrude from the guide groove of the outer joint member without dropping the ball, the joint protrudes outward from the guide groove of the outer joint member as the joint rotates or bends. The ball is returned to the guide groove again. At this time, the ball and the opening end of the outer joint member interfere with each other, and the smooth operation of the constant velocity universal joint may be hindered.

  An object of the present invention is to provide a fixed constant velocity universal joint capable of realizing a higher operating angle than the conventional one by allowing it to protrude from the guide groove of the outer joint member without dropping the ball. Is to operate the constant velocity universal joint smoothly.

  In order to solve the above-mentioned problems, the present invention forms 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 guide grooves extending in the axial direction on a spherical outer peripheral surface. Inner joint member, a torque transmission ball disposed on each of a plurality of ball tracks formed by cooperation of the guide groove of the outer joint member and the guide groove of the inner joint member, and a cage for holding the torque transmission ball In the fixed type constant velocity universal joint, the region of the guide groove of the inner joint member including the end portion on the back side of the joint is an arc centered on the joint center, and the cage for housing the ball By making the window opening size on the outer peripheral side of the window smaller than the diameter of the ball, it is possible to protrude from the guide groove of the outer joint member without dropping the ball, and the joint opening side end of the guide groove of the outer joint member The radius direction Characterized in that the outwardly open guide portion.

  As described above, in the constant velocity universal joint of the present invention, the joint opening side end of the guide groove of the outer joint member is a guide portion that opens outward in the radial direction. This guide part can smoothly return the ball that has come out of the guide groove of the outer joint member to the guide groove, so that interference between the ball and the outer joint member is avoided, and the joint can be operated even when a large operating angle is taken. It can be operated smoothly.

  This guide part can be made into the curve shape centering on the curvature center by the side of the opening outer diameter of an outer joint member, for example. Or it can be set as the linear form which the internal diameter increases uniformly toward the opening part of an outer joint member.

  As described above, according to the present invention, in the fixed type constant velocity universal joint capable of realizing a higher operating angle than the conventional one by allowing it to protrude from the guide groove of the outer joint member without dropping the ball, Interference with the outer joint member can be prevented, and the constant velocity universal joint can be operated smoothly.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS. FIG. 1 shows a fixed type constant velocity universal joint according to the present invention. FIG. 1 (A) shows a state where the operating angle is 0 °, and FIG. 1 (B) shows a state where the limit operating angle (60 °) is taken. is there. The fixed type constant velocity universal joint includes an outer joint member 1 in which a plurality of (for example, eight) curved guide grooves 1b are formed on the inner circumferential spherical surface 1a in the axial direction, and a plurality (for example, eight) of the outer circumferential spherical surface 2a. ) In the axial direction, the inner joint member 2 having a spline (or serration) hole 2c, the shaft 3 having one end fitted in the spline hole 2c, and the guide of the outer joint member 1 Torque transmitting balls 4 arranged one by one on a plurality of (for example, eight) ball tracks formed in cooperation with the groove 1b and the guide groove 2b of the inner joint member 2, and a cage for holding the balls 4 And 5. The number of guide grooves is not limited to 8, and may increase to 9, 10, 11, 12,.

The fixed type constant velocity universal joint shown in FIG. 1 is called a double offset type. Guide grooves 1b of the outer joint member 1 (hereinafter, outer ring guide grooves 1b) is formed an O ₁ points offset from the joint center O to the center of curvature and the circular arc shape. A guide groove 2b (hereinafter referred to as an inner ring guide groove 2b) of the inner joint member 2 has a first arc portion 2b1 including a joint center O as a center of curvature and an end portion of the guide groove 2b on the inner side of the joint, and a first arc portion 2b1. provided in the joint opening side, and the O ₂ point offset from the joint center O in the second arc portion 2b2 that center of curvature. The center of curvature O ₁ of the outer ring guide groove 1b, and the center of curvature O ₂ of the second arc portion 2b2 of the inner ring guide grooves 2b, relative to the joint center O, equidistant with only be offset in the axial direction opposite, It is offset by an equal distance from the joint axis in the direction of increasing the radius of curvature. Thereby, the ball track formed by the cooperation of the outer ring guide groove 1b and the corresponding inner ring guide groove 2b has a wedge shape which opens toward the opening side of the joint.

The joint opening side end portion of the outer ring guide groove 1b is a guide portion 1c opened outward in the radial direction. FIG. 2 shows only the outer ring guide groove 1b and the groove bottom of the guide portion 1c in FIG. Guide portion 1c is formed of, for example, the O ₃ points on the outer diameter side of the opening section of the outer joint member 1 in an arcuate shape with a radius R2 which is a center of curvature, are smoothly continuous with outer ring guide groove 1b. If the opening angle δ of the guide portion 1c (the angle formed between the tangent at the opening end of the guide portion 1c and the joint axis) is too small, the ball 4 and the outer joint member 1 interfere with each other. The guide function of smoothly returning the ball 4 that has come out of the ball to the ball track cannot be achieved. For this reason, the size of the opening angle δ of the guide portion 1c is desirably set to 5 ° to 45 °, preferably 10 ° to 20 °.

  The shape of the guide portion 1c is not limited to the above. FIG. 3 shows another example of the guide portion 1c. The guide portion 1c is linearly inclined outwardly in the radial direction by an angle δ from the joint axial direction of the outer joint member 1, that is, the inner diameter of the guide portion 1c increases uniformly toward the opening side of the outer joint member 1. It is formed in a straight line. In FIG. 3, a corner is formed at the boundary between the outer ring guide groove 1 b and the guide 1 c, but the corner may be rounded and smoothly continuous.

  The cage 5 is formed of an annular member, and the outer peripheral surface thereof is an outer peripheral spherical surface 5 a that is in sliding contact with the inner peripheral spherical surface 1 a of the outer joint member 1, and the inner peripheral surface is in sliding contact with the outer peripheral spherical surface 2 a of the inner joint member 2. The inner peripheral spherical surface 5b is used. The centers of curvature of the outer peripheral spherical surface 5a and the inner peripheral spherical surface 5b of the cage 5 are all joint centers O. The same number of windows 5c as the balls 4 are formed through the peripheral wall of the cage 5 by grinding or milling. The shape of the window 5c is, for example, a rectangle, and is formed at equal intervals in the circumferential direction of the cage 5.

  An inner diameter surface on the joint opening side of the cage 5 is a cylindrical surface 5d having a constant inner diameter over a predetermined width, and a retaining ring 7 (a circlip) is fitted into a groove 5d1 formed in the cylindrical surface 5d. The guide ring 6 is fitted into a narrow annular wedge space formed inside the retaining ring 7 and up to the window 5c of the cage 5. 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 cylindrical surface 5 d of the cage 5. Further, the outer end of the guide ring 6 comes into contact with the inner surface of the retaining ring 7. A certain gap is secured between the inner end of the guide ring 6 and the ball 4.

  The window 5 c of the cage 5 has an outer peripheral side window opening dimension smaller than the diameter of the ball 4. That is, the ball guide surfaces facing the axial direction of the cage 5 are linearly parallel to each other with an interval equal to the ball diameter, but the outer diameter side of the ball guide surface is slightly narrower than the ball diameter. It becomes a constriction before. The 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 form a concave arc shape that matches the outer peripheral curvature of the ball.

The constant velocity universal joint according to the present invention is configured as described above. When the outer joint member 1 and the inner joint member 2 are at the operating angle of 0 ° in FIG. 1A, the ball 4 is formed by the outer ring guide groove 1b and the inner ring. Due to the effect that the curvature centers O ₁ and O ₂ of the second circular arc portion 2b2 of the guide groove 2b are offset, they are held in a plane including the joint center O and perpendicular to the rotation axis, and torque is transmitted in this state. Is done.

  In the state where the outer joint member 1 and the inner joint member 2 are bent to the limit operating angle θ as shown in FIG. 1B, the shaft 3 contacts the open end of the outer joint member 1. The torque transmission ball 4 is oriented in a plane that bisects the angle θ by the cage 5, thereby ensuring constant velocity of the joint.

  In the state shown in FIG. 1B, some of the balls 4 come out of the outer ring guide groove 1b and contact the first arc portion 2b1 of the inner ring guide groove 2b. At this time, since the arc portion 2b1 is centered on the joint center O, the center position of the ball 4 is not separated from the joint center O. Therefore, the ball 4 can be held between the inner ring guide groove 2 b and the cage 5. Further, as described above, by setting the window opening size of the window 5c of the cage 5 to be smaller than the ball diameter, the ball 4 can be moved by the cage 5 to the inner ring guide groove 2b even outside the outer joint member 1. Since it can be held in the side, it can prevent that the ball | bowl 4 falls out of the holder | retainer 5. FIG. In this way, the limit operating angle of the constant velocity universal joint can be increased by allowing the ball 4 to protrude from the guide groove 1b of the outer joint member 1 without dropping off.

  In such a constant velocity universal joint, the ball 4 protruding outward from the guide groove 1b of the outer joint member 1 is returned to the guide groove 1b again as the joint rotates or bends. At this time, if the ball 4 interferes with the opening end of the outer joint member 1, the smooth operation of the constant velocity universal joint 1 may be hindered. In the constant velocity universal joint of the present invention, the ball 4 can be smoothly accommodated in the outer ring guide groove 1b by the guide portion 1c provided at the opening end of the outer ring guide groove 1b (see FIG. 4). Accordingly, interference between the ball 4 and the outer joint member 1 is avoided, and the joint can be operated smoothly.

The longitudinal section which shows the state where the fixed type constant velocity universal joint which concerns on this invention took (A) operating angle 0 degree and (B) limit operating angle (60 degrees). The enlarged view of the guide groove 1b of the outer joint member 1. FIG. The enlarged view which shows the other example of the guide groove 1b of the outer joint member 1. FIG. The longitudinal cross-sectional view which shows the state which bent the fixed type constant velocity universal joint.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Outer joint member 1a Inner spherical surface 1b Outer ring guide groove 1c Guide portion 2 Inner joint member 2a Outer spherical surface 2b Inner ring guide groove 2b1 First arc portion 2b2 Second arc portion 2c Spline hole 3 Shaft 4 Ball 5 Cage 6 Guide ring 7 Retaining ring O Joint center

Claims (3)

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 In a fixed type constant velocity universal joint including a torque transmission ball arranged on each of a plurality of ball tracks formed by cooperation of a groove and a guide groove of an inner joint member, and a cage for holding the torque transmission ball ,
Of the guide groove of the inner joint member, a region including the end portion on the inner side of the joint is an arc centered on the joint center, and the window opening size on the outer peripheral side of the window of the cage housing the ball is the diameter of the ball. By making the ball smaller, it is possible to protrude from the guide groove of the outer joint member without dropping the ball, and the joint opening side end of the guide groove of the outer joint member is opened radially outwardly. A fixed type constant velocity universal joint.   2. The fixed type constant velocity universal joint according to claim 1, wherein the guide portion has a curved shape centering on the center of curvature of the outer joint member on the outer diameter side of the opening.   2. The fixed type constant velocity universal joint according to claim 1, wherein the guide portion has a linear shape whose inner diameter uniformly increases toward the opening of the outer joint member.

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