JP2007218353A - Fixed type constant velocity universal joint - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fixed type constant velocity universal joint having improved durability at a high angle while keeping itself at a high operating angle. <P>SOLUTION: A track groove 22 of an outward member has a corner side track groove 22a whose curvature center is located on the corner side beyond the spherical center of the outer member in the axial direction of the center of the joint, and an opening side track groove 22b whose curvature center is located on the outer diameter side beyond the center of a ball. A track groove 25 of an inward member has an opening side track groove 25b whose curvature center is located on the side of an opening portion opposite to the curvature center of the corner side track groove 22a of the outward member and equally distant therefrom in the axial direction of the center of the joint. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a fixed type constant velocity universal joint, and more particularly to a fixed type constant velocity joint that is used in a power transmission system of an automobile or various industrial machines and allows only angular displacement between two axes of a driving side and a driven side. It relates to a universal joint.

  For example, there is a fixed type constant velocity universal joint as a kind of constant velocity universal joint used as means for transmitting rotational force from an engine of an automobile to wheels at a constant speed. This fixed type constant velocity universal joint has a structure in which two shafts on the driving side and the driven side are connected and the rotational torque can be transmitted at a constant speed even if the two shafts have an operating angle. In general, as the above-mentioned fixed type constant velocity universal joint, a Barfield type (BJ) and an undercut free type (UJ) are widely known.

  For example, a fixed constant velocity universal joint of BJ type is an outer member in which a plurality of track grooves 2 are formed along the axial direction at equal intervals in the circumferential direction on the inner spherical surface 1 as shown in FIGS. An outer ring 3, an inner ring 6 as an inner member in which a plurality of track grooves 5 paired with the track grooves 2 of the outer ring 3 are formed on the outer spherical surface 4 along the axial direction at equal intervals in the circumferential direction, and the outer ring 3 Between the track groove 2 of the inner ring 6 and the track groove 5 of the inner ring 6 to transmit torque, and between the inner spherical surface 1 of the outer ring 3 and the outer spherical surface 4 of the inner ring 6, the balls 7 And a cage 8 for holding the A shaft 11 is fitted into the inner ring 6.

In this constant velocity universal joint, the contact point between the track groove and the ball does not come off the track and can take a large operating angle. Therefore, the center of curvature O1 of the track groove 2 of the outer ring 3 and the center of curvature of the track groove 5 of the inner ring 6 are obtained. O2 is offset in the axial direction by an equal distance f with respect to the joint center O (Patent Document 1). By providing the track offset in this way, each of the track grooves 2 and 5 is shallower from the center in the axial direction on the bottom side (back side) of the outer ring and deeper on the opening side of the outer ring. As a result, the outer ring 3 A wedge-shaped ball track is formed in which the radial interval gradually increases from the bottom side (back side) to the opening side. In FIG. 4, the outer ring track depth at a certain angle γ is a1.
JP 2005-221033 A JP 2005-188620 A

  In the case of the offset as described in Patent Document 1, Patent Document 2, etc., as described above, the contact angle between the track groove and the ball does not come off from the track groove, and the joint operating angle is increased. The center of curvature O1 is the opening side, and the center of curvature O2 of the track groove 5 of the inner ring 6 is the back side. For this reason, the groove depth a1 on the back side of the track of the outer ring 3 becomes shallow, and if it becomes so shallow, the allowable load torque becomes small on the back side of the track.

  In order to solve this, as shown in FIG. 6, the center of curvature O1 of the track groove 2 of the outer ring 3 is on the back side from the joint center O, and the center of curvature O2 of the track groove 5 of the inner ring 6 is on the opening side. Thus, it is conceivable to deepen the back side of the track groove 2 of the outer ring 3. However, if the back side of the track groove 2 of the outer ring 3 is deepened, the ball track formed by the track grooves 2 and 5 has a shape in which the radial interval gradually decreases from the back side of the outer ring 3 toward the opening side. It becomes. For this reason, in such a case, the operability cannot be ensured, or when the operating angle is taken, the load point of the ball 7 may be removed from the ball track, so that a high operating angle cannot be taken.

  In view of the above problems, the present invention provides a fixed type constant velocity universal joint capable of improving durability at a high angle while maintaining a high operating angle.

  The fixed type constant velocity universal joint of the present invention includes an outer member in which a plurality of track grooves are formed on the inner spherical surface along the axial direction at equal intervals in the circumferential direction, and a plurality of track grooves on the outer spherical surface in the circumferential direction, etc. An inner member formed along the axial direction at intervals, a plurality of balls that are interposed between the track grooves of the outer member and the track grooves of the inner member, and transmit torque; and In a fixed type constant velocity universal joint provided with a cage for holding a ball interposed between an inner spherical surface and an outer spherical surface of the inner member, the track groove of the outer member has an axial direction from the joint center to the center of curvature. And a track groove of the inner member, and a track groove of the inner member, and a track groove of the inner member having a center of curvature provided on the outer diameter side of the ball center. The center of curvature from the joint center to the axial direction on the back side of the outer member. Tsu is intended to center of curvature opposite the opening side of the click groove that a just apart opening side track groove provided equidistantly.

  In the present invention, the back side of the track groove of the outer member can be deepened by shifting the center of curvature of the back side track groove of the outer member from the joint center to the back side of the outer member in the axial direction. it can. As a result, the allowable load torque can be increased while preventing the ball from climbing on the rear side of the outer ring. Further, an opening-side track groove is formed in the opening of the outer member, so that when the operating angle is taken, the swing of the shaft is not restricted by the opening of the outer member, that is, the load of the ball The operating angle can be increased without deviating from the points.

  As for the track groove of the outer member, it is desirable that the back-side track groove and the opening-side track groove are continuous, or the back-side track groove and the opening-side track groove are continuous via a straight portion. .

  It is preferable that the curvature radius of the inner track groove of the outer member is larger than the curvature radius of the opening track groove. Further, the finishing track after forging can be applied to the inner side track groove of the outer member, and the opening side track groove of the outer member can be finished by forging.

  The back side of the track groove of the outer member can be deepened, and the allowable load torque can be increased while preventing the ball from climbing on the back side of the outer member. This enables stable torque transmission between the outer member and the inner member even when the operating angle is taken. Further, by forming the opening side track groove in the opening of the outer member, the swinging of the shaft is not restricted by the opening of the outer member, and the operating angle can be increased. The range of use of the joint is expanded.

  The outer member's track groove has a smooth operating angle by connecting the back side track groove and the open side track groove continuously, or by connecting the back side track groove and the open side track groove via a straight line. Can be taken.

  By making the curvature radius of the outer track groove of the outer member's track groove larger than the curvature radius of the opening side track, the back side of the ball track becomes a gently curved portion with a large curvature radius, and the ball is also smooth on this back side. Can be moved to. Also, the opening side of the ball track has a steep curve with a small radius of curvature, and the opening of the outer member opens large, making it easy to increase the operating angle.

  The outer side track groove of the outer member is polished or ground after forging, and the outer side track groove of the outer member is forged. For this reason, it is possible to smoothly form a ball track in a range where the ball rolls.

  An embodiment of a fixed type constant velocity universal joint according to the present invention will be described with reference to FIGS.

  As shown in FIG. 1, the fixed type constant velocity universal joint includes an outer ring 23 as an outer member in which a plurality of track grooves 22 are formed in the inner spherical surface 21 along the axial direction at equal intervals in the circumferential direction, and the outer spherical surface. 24, a plurality of track grooves 25 paired with the track grooves 22 of the outer ring 23 are formed along the axial direction at equal intervals in the circumferential direction, and the track grooves 22 and the inner rings 26 of the outer ring 23 are formed as inner members. A plurality of balls 27 that transmit torque by being interposed between the track grooves 25 and a cage 28 that is interposed between the inner spherical surface 21 of the outer ring 23 and the outer spherical surface 24 of the inner ring 26 and holds the balls 27. I have. The plurality of balls 27 are accommodated in pockets 29 formed in the cage 28 and arranged at equal intervals in the circumferential direction. A chamfer portion 30 is provided at the open end of the outer ring 23 to prevent the shaft 31 connected to the inner ring 26 from interfering with the outer ring 23 when the outer ring 23 and the inner ring 26 have a high operating angle. ing.

  The track groove 22 of the outer ring 23 includes a back side track groove 22a provided by shifting the center of curvature O1 from the joint center O in the axial direction to the side opposite to the opening (back) of the outer ring 23, and a center of curvature O3 (see FIG. 3). Has an opening-side track groove 22b provided on the outer diameter side of the ball center. Further, the track groove 25 of the inner ring 26 has an opening provided with the center of curvature O2 spaced apart from the joint center O in the axial direction by an equal distance f on the opening side opposite to the center of curvature O1 of the inner side track groove 22a of the outer ring 23. A side track groove 25b and a back side track groove 25a provided with a radius of curvature closer to the outer diameter side than the ball center are provided.

  Thus, as shown in FIG. 3, the track center line L formed in the track groove 22 of the outer ring 23 has a center of curvature on the side of the joint center O and an anti-opening side curved portion 32a, and the center of curvature is a ball. A flat S-shape having an opening-side curved portion 32b on the outer diameter side of the center can be formed. Further, the track center line L1 (see FIG. 2) formed by the track groove 25 of the inner ring 26 includes an opening-side curved portion 33b having a center of curvature on the joint center O side and a center of curvature outside the center of the ball. It can be made into the flat S shape provided with the anti-opening side curved part 33a in a diameter side. At this time, in the track groove 22 of the outer ring 23, as shown in FIG. 3, the curvature radius R1 of the counter opening side curved portion 32a is made larger than the curvature radius R2 of the opening side curved portion 32b.

  The track groove 22 of the outer member (outer ring 23) and the track groove 25 of the inner member have a flat S-shaped track center lines L and L1, respectively, so that the back side track grooves 22a and 25a and the open side track groove 22b and 25b are continuous. Then, the back side track groove 22a of the track groove 22 of the outer ring 23 is subjected to finishing after forging, and the opening side track groove 22b of the outer ring 23 is finished by forging. As the finishing process, polishing process or cutting process (quenching process) can be performed. At this time, it is preferable that the track grooves 25 of the inner ring 26 (the back side track grooves 25a and the opening side track grooves 25b) are subjected to finishing after forging. In FIG. 1, the outer ring track depth at a certain angle γ as in FIG. 4 is a2.

  In the present invention, the back side of the track groove 22 can be deepened by providing the curvature center O1 of the back side track groove 22a of the outer ring 23 on the side opposite to the opening of the outer ring 23 in the axial direction from the joint center O. When comparing the depths of the track grooves in the conventional one shown in FIG. 4 and that shown in FIG. 1, the depth shown in FIG. 4 is a1, and the depth a2 shown in FIG. In this case, a2> a1. In this way, on the back side, the allowable load torque can be increased while preventing the ball 27 from climbing, and stable torque transmission between the outer ring 23 and the inner ring 26 is possible even when the operating angle is taken.

  In addition, an opening-side track groove 22b is formed on the opening side of the outer ring 23. With this, when the operating angle is set, the swing of the shaft 31 is not restricted by the opening of the outer ring 23 and the operating angle is increased. be able to. That is, in the case shown in FIG. 7, the maximum operating angle is θ1, whereas the maximum operating angle of the present invention is θ2, as shown in FIG. In this case, θ2> θ1, and the maximum operating angle can be increased.

  The rear track groove 22a of the track groove 22 of the outer ring 23 is finished after forging, and the opening side track groove 22b of the outer ring 23 is finished by forging. Can be formed smoothly.

  Since the track grooves 22 of the outer ring 23 and the track grooves 25 of the inner ring 26 are continuous with the rear track grooves 22a and 25a and the open track grooves 22b and 25b, respectively, the operating angle can be taken smoothly.

  By making the radius of curvature of the back side track groove 22a of the track groove 22 of the outer ring 23 larger than the radius of curvature of the opening side track groove 22b, the back side of the ball track becomes a gently curved portion with a large curvature radius. The ball can move smoothly. In addition, the opening side of the ball track has a steep curve with a small radius of curvature, and the opening of the outer member is greatly opened so that the operating angle is easily increased.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications are possible. For example, the back side track grooves 22a and 25a and the opening side track grooves 23b and 25b And may be continuous via straight portions. As described above, even if the linear portion is provided, the operating angle can be taken smoothly. Further, the number of balls 27 is not limited to six and can be increased or decreased. However, considering the torque transmission function, it is preferable that the number of balls 27 be six or more.

It is principal part sectional drawing of the fixed type constant velocity universal joint which shows embodiment of this invention. It is principal part sectional drawing of the state which took the operating angle of the said fixed type constant velocity universal joint. It is a principal part expanded sectional view of the outer member of the said fixed type constant velocity universal joint. It is principal part sectional drawing of the conventional fixed type constant velocity universal joint. It is a principal front simplified view of the conventional fixed type constant velocity universal joint. FIG. 6 is a cross-sectional view of a principal part of a fixed type constant velocity universal joint in which the center of curvature of a track groove of the outer ring is on the back side and the center of curvature of the track groove of the inner ring is on the opening side. FIG. 7 is a cross-sectional view of a main part in a state where an operating angle is taken in the fixed type constant velocity universal joint of FIG. 6.

Explanation of symbols

21 inner spherical surface 22 track groove 22a back side track groove 22b opening side track groove 24 outer spherical surface 25 track groove 25b opening side track groove 27 ball

Claims (5)

An outer member in which a plurality of track grooves are formed in the inner spherical surface along the axial direction at equal intervals in the circumferential direction, and an inner member in which the plurality of track grooves are formed in the outer spherical surface at equal intervals in the circumferential direction along the axial direction. An outer member, a plurality of balls that are interposed between the outer member track groove and the inner member track groove to transmit torque, and an inner spherical surface of the outer member and an outer spherical surface of the inner member In a fixed type constant velocity universal joint provided with a cage for holding a ball interposed therebetween,
The track groove of the outer member is provided with a back side track groove provided by shifting the center of curvature axially from the joint center to the back side from the spherical center of the outer member, and the center of curvature is provided on the outer diameter side from the ball center. An opening-side track groove, and the track groove of the inner member is equidistant from the joint center in the axial direction to the opening side opposite to the curvature center of the outer track groove of the outer member. A fixed type constant velocity universal joint comprising an opening-side track groove provided at a distance.   2. The fixed type constant velocity universal joint according to claim 1, wherein the outer side track groove and the opening side track groove are continuous with each other.   2. The fixed type constant velocity universal joint according to claim 1, wherein the outer side track groove and the opening side track groove are continuous via a straight portion.   The fixed type constant velocity universal joint according to any one of claims 1 to 3, wherein a radius of curvature of the outer side track groove of the outer member is larger than a radius of curvature of the opening side track groove.   The back side track groove of the track groove of the outer member is subjected to finishing after forging, and the opening side track groove of the outer member is finished by forging. Fixed constant velocity universal joint.

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