JP2007239875A - Fixed constant velocity universal joint - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fixed constant velocity universal joint capable of improving durability at a high angle, while keeping a high operating angle. <P>SOLUTION: This fixed constant velocity universal joint has an outer member of forming a track groove 22 on an inner spherical surface, an inner member of forming a track groove 25 on an outer spherical surface, and a ball 27 transmitting torque by being interposed between the track groove 22 of the outer member and the track groove 25 of the inner member. The track groove 22 of the outer member has two kinds of a first track groove 41 and a second track groove 42. The first track groove 41 has the innermost side track groove 41a formed by making the curvature center axially dislocated to the innermost side from the spherical surface center of the outer member from the joint center, and a tapered opening side track groove 41b deepening toward the opening side from the innermost side. The second track groove 42 has the innermost side track groove 42a formed by making the curvature center axially dislocated to the innermost side from the spherical surface center of the outer member from the joint center, and an opening side track groove 42b of arranging the curvature center on the outer diameter side from the ball center. <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, as shown in FIGS. 7 and 8, the BJ type fixed type constant velocity universal joint is an outer member in which a plurality of track grooves 2 are formed on the inner spherical surface 1 along the axial direction at equal intervals in the circumferential direction. 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. 7, the outer ring track depth at a certain angle γ is a1.
JP-A-10-103365

  In the case of the offset as described in Patent Document 1 and the like, as described above, since the contact angle between the track groove and the ball does not come off the track groove and the joint operating angle is increased, the center of curvature O1 of the track groove 2 of the outer ring 3 is obtained. 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. 9, the center of curvature O1 of the track groove 2 of the outer ring 3 is set to 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 set to 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 the fixed type constant velocity universal joint provided with a cage for holding a ball interposed between the inner spherical surface and the outer spherical surface of the inner member, the track groove of the outer member is a first track groove and a second track groove. The first track groove is formed by shifting the center of curvature from the joint center in the axial direction to the back side from the spherical center of the outer member, and from the back side toward the opening side. And a taper-shaped opening-side track groove that is deep, and the second track groove is The those comprising a back side track groove than the spherical center provided by shifting the rear side of the outer member from the joint center in the axial direction and an opening side track groove having a center of curvature on the outer diameter side than the center of the ball.

  In the present invention, in the first track groove and the second track groove of the outer member, the center of curvature of the rear track groove is shifted from the joint center to the rear side in the axial direction, so that the depth of the track groove of the outer member is increased. You can deepen the side. As a result, the allowable load torque can be increased while preventing the ball from climbing on the rear side of the outer ring. In addition, a tapered opening-side track groove that is deeper from the back side toward the opening side is provided on the opening side of the first track of the outer member, and the center of curvature is provided on the opening side of the second track of the outer member. Since the opening-side track grooves provided on the outer diameter side from the center are provided, the opening sides of the first track grooves and the second track grooves are widened in the outer diameter direction. For this reason, when taking the operating angle, the swinging of the shaft is not restricted by the opening of the outer member, that is, the operating angle can be increased without the ball load point being deviated.

  The track groove of the inner member has two types, a first track groove and a second track groove. The first track groove of the inner member has a center of curvature extending axially from the joint center to the back of the outer member. An opening side track groove provided at an equal distance away from the opening side opposite to the center of curvature of the side track groove, and a tapered back side track groove that becomes shallower from the opening side toward the back side. The second track groove of the member has an opening side track groove provided at an equal distance from the joint center in the axial direction from the joint center to the opening side opposite to the curvature center of the inner side track groove of the outer member, and A back side track groove having a center of curvature provided on the outer diameter side of the ball center.

  Thus, since the track groove of the inner member has two types of the first track groove and the second track groove, the first track groove of the inner member and the first track of the outer member corresponding thereto are provided. The ball track constituted by the groove and the second track groove of the inner member and the corresponding second track groove of the outer member have a shape in which the ball rolls smoothly. Can do.

  Moreover, the track grooves (all or part of the first track grooves and the second track grooves) of the outer member can be finished by forging.

  The back side of the first track groove and the second 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. On the opening side of the outer member, the first track groove and the second track groove are expanded in the outer diameter direction. For this reason, the swinging of the shaft is not restricted by the opening of the outer member, the operating angle can be increased, and the use range of this fixed type constant velocity universal joint is expanded.

  Since the track groove of the outer member has two types of the first track groove and the second track groove, the load applied to the cage can be balanced, and the durability and efficiency can be improved. In particular, if the first track grooves and the second track grooves are alternately arranged along the circumferential direction, the load applied to the cage at a low angle is excellent in balance and durability and efficiency can be further improved. .

  A ball track composed of a first track groove of the inner member and a corresponding first track groove of the outer member, a second track groove of the inner member, and a second track groove of the outer member corresponding thereto And a ball track configured to smoothly roll the ball. For this reason, various operating angles can be taken smoothly.

  The track grooves (all or part of the first track grooves and the second track grooves) of the outer member can be finished by forging. Thereby, a ball track in a range where the ball rolls can be smoothly formed.

  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, and a track of the outer ring 23 on the outer spherical surface 24. Torque is provided between an inner ring 26 as an inner member in which a plurality of track grooves 25 paired with the groove 22 are formed along the axial direction, and between the track grooves 22 of the outer ring 23 and the track grooves 25 of the inner ring 26. 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 ball 27. 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 first track groove 41 and a second track groove 42 as shown in FIGS. That is, the first track grooves 41 and the second track grooves 42 are alternately arranged along the circumferential direction. The track grooves 22 are preferably 6 or more in consideration of the torque transmission function, and 8 are optimal. For this reason, it is preferable that the number of the first track grooves 41 is four and the number of the second track grooves 42 is four.

  The track groove 25 of the inner ring 26 also has a first track groove 51 and a second track groove 52 as shown in FIGS. In this case, the first track groove 51 corresponds to the first track groove 41 of the outer ring 23 to form a ball track with the first track grooves 41, 51, and the second track groove 52 is the second track groove 42 of the outer ring 23. Corresponding to the above, a ball track is formed by the second track grooves 42 and 52.

  As shown in FIGS. 1 to 3, the first track groove 41 includes a back-side track groove 41 a that is provided by shifting the center of curvature O1 from the joint center O in the axial direction toward the side opposite to the opening (back) of the outer ring 23. And a tapered opening-side track groove 41b that becomes deeper from the back side toward the opening side. Further, the first track groove 51 of the inner ring 26 is provided with the center of curvature O2 separated 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 41a of the outer ring 23. An opening-side track groove 51b and a tapered back-side track groove 51a that becomes shallower from the opening side toward the back side.

  In this case, the back track groove 41a of the first track groove 41 of the outer ring 23 passes through a plane S including the joint center O and an O1 inclined by α from the back start point 33 perpendicular to the joint axis (outer ring axis) LA. The opening side track groove 41b starts from the end point 34. Further, the opening side track groove 51b of the first track groove 51 of the inner ring 26 extends from the opening side start point 35 to a plane passing through the plane S and α2 inclined by α1, and the back side track groove 52a starts from this end point 36.

  As a result, the track center line L formed in the first track groove 51 of the outer ring 23 is defined as a back-side curved portion La having a curvature center of O1 and an opening-side straight portion Lb continuous to the back-side curved portion La. be able to. That is, the opening-side straight portion Lb is inclined from the inner side toward the opening side toward the outer diameter side with an inclination angle (inclination angle with respect to the joint axis LA) α (see FIG. 3).

  Also, the track center line L1 formed in the first track groove 52 of the inner ring 26 is an opening-side curved portion L1b having a center of curvature of O2 and a back-side straight portion L1a continuous to the opening-side curved portion L1b. Can do. That is, the back straight portion L1a is inclined from the opening side toward the outer diameter side from the opening side at an inclination angle (inclination angle with respect to the joint axis LA) α1 (see FIG. 1). The inclination angle α1 and the inclination angle α are the same angle.

  In this case, the inclination angles α and α1 can be arbitrarily set, but the ball 27 is formed in the ball track constituted by the first track groove 41 of the outer ring 23 and the corresponding first track groove 51 of the inner ring 26. Is preferably set to about 3 to 6 degrees, for example, in order to smoothly roll. If it is smaller than this range, the track opening is narrowed, the operating angle that can be taken is reduced, and the smooth rolling of the ball 27 may be impaired. If it is larger than this range, the amount of movement of the ball 27 in the radial direction is increased, the required thickness of the cage 28 is increased, and the track groove depth is reduced.

  The first track groove 41 of the outer ring 23 is finished by forging. The first track groove 51 of the inner ring 26 is also preferably finished by forging. In this case, all or a part of the first track grooves 41 and 51 (for example, a portion where the ball 27 rolls) may be used. In FIG. 1, the outer ring track depth at a certain angle γ as in FIG. 7 is a2.

  As shown in FIGS. 4 to 6, the second track groove 42 of the outer ring 23 is formed by shifting the center of curvature O <b> 1 from the joint center O in the axial direction to the side opposite to the opening (back) of the outer ring 23. 42a and an opening-side track groove 42b in which the center of curvature O3 (see FIG. 6) is provided on the outer diameter side of the ball center. Further, the second track groove 52 of the inner ring 26 is provided with the center of curvature O2 separated from the joint center O in the axial direction by an equidistant distance f on the opening side opposite to the center of curvature O1 of the inner side track groove 42a of the outer ring 23. The opening side track groove 52b and the back side track groove 52a provided with a radius of curvature closer to the outer diameter side than the center of the ball.

  Thereby, as shown in FIG. 5, the track center line L3 formed by the second track groove 42 of the outer ring 23 has a back side curved portion L3a having a center of curvature on the joint center O side and a center of curvature. A flat S-shape including an opening-side curved portion L3b located on the outer diameter side of the ball center can be formed. The track center line L4 formed by the second track groove 52 of the inner ring 26 includes an opening-side curved portion L4b having a center of curvature on the joint center O side and a center of curvature on the outer diameter side of the ball center. It can be made into the flat S character shape provided with a certain back side curved part L4a. At this time, in the second track groove 42 of the outer ring 23, as shown in FIG. 6, the curvature radius R1 of the back-side curved portion L3a is made larger than the curvature radius R2 of the opening-side curved portion L3b.

  The second track groove 42 of the outer member (outer ring 23) and the second track groove 52 of the inner member have flat S-shaped track center lines L3 and L4, respectively. The opening side track grooves 42b and 52b are continuous. The second track groove 42 of the outer ring 23 is finished by forging. At this time, the second track groove 52 of the inner ring 26 is also preferably finished by forging. In these cases, all or part of the second track grooves 42 and 52 (for example, a portion where the ball 27 rolls) may be used. In FIG. 4, the outer ring track depth at a certain angle γ as in FIG. 7 is a2.

  In the present invention, the back side of the first track groove 41 and the second track groove 42 of the outer member can be deepened. For this reason, it is possible to increase the allowable load torque while preventing the ball 27 from climbing on the back side. 7 is compared with the depth shown in FIG. 1 and FIG. 4, the depth shown in FIG. 7 is a1, and the depth shown in FIGS. If the depth is a2, then 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.

  On the opening side of the outer member, the first track groove 41 and the second track groove 42 are expanded in the outer diameter direction, and when the operating angle is taken, the swing of the shaft 11 is the opening of the outer member. Therefore, the operating angle can be increased. That is, in the case shown in FIG. 10, 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 track groove of the outer member has the first track groove 41 and the second track groove 42, so that the load applied to the cage 28 can be balanced and the durability and efficiency can be improved. . In particular, if the first track grooves 41 and the second track grooves 42 are alternately arranged along the circumferential direction, the balance of the load applied to the cage 28 at a low angle is excellent, and durability and efficiency are further improved. It becomes possible.

  The track groove 25 of the inner member has two types, a first track groove 51 and a second track groove 52, the first track groove 51 of the inner member and the first track groove of the outer member corresponding thereto. A ball track constituted by 41 and a second track groove 52 of the inner member and a corresponding second track groove 42 of the outer member, and a shape in which the ball rolls smoothly. can do. For this reason, various operating angles can be taken smoothly.

  Since the first track groove 41 and the second track groove 42 of the outer ring 23 are finished by forging, a ball track in a range where the ball 27 rolls can be formed smoothly.

  The first and second track grooves 41 and 42 of the outer ring 23 and the first and second track grooves 51 and 52 of the inner ring 26 are respectively connected to the back side track grooves 41a and 42a and the opening side track grooves 41b and 42b. Therefore, the operating angle can be taken smoothly.

  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 can be made. For example, the first track grooves 41, 51 and the second track grooves 42, 52 are possible. And the number of the first track grooves 41 and 51 may be different from the number of the second track grooves 42 and 52.

It is sectional drawing in the 1st track groove of the fixed type constant velocity universal joint which shows embodiment of this invention. It is sectional drawing in the 1st track groove of the state which took the operating angle of the said fixed type constant velocity universal joint. It is an expanded sectional view which shows the 1st track groove of the outer member of the said fixed type constant velocity universal joint. It is principal part sectional drawing in the 2nd track groove of the said fixed type constant velocity universal joint. It is sectional drawing in the 1st track groove in the 2nd track groove of the state which took the operating angle of the said fixed type constant velocity universal joint. It is an expanded sectional view which shows the 2nd track groove 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. 10 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. 9.

Explanation of symbols

21 inner spherical surfaces 22 and 25 track grooves 24 outer spherical surfaces 27 balls 28 cages 41 and 5 first track grooves 41a and 42a back side track grooves 41b and 42b opening side track grooves 42 and 52 second track grooves

Claims (3)

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 has two types, a first track groove and a second track groove, and the first track groove is a back track groove provided by shifting the center of curvature from the joint center to the back in the axial direction. And a tapered opening-side track groove that becomes deeper from the back side toward the opening side, and the second track groove includes a back-side track groove that is provided by shifting the center of curvature from the joint center to the back side in the axial direction. A fixed type constant velocity universal joint comprising: an opening side track groove having a center of curvature provided on the outer diameter side of the center of the ball.   The track groove of the inner member has two types, a first track groove and a second track groove. The first track groove of the inner member has a center of curvature extending axially from the joint center to the back of the outer member. An opening side track groove provided at an equal distance away from the opening side opposite to the center of curvature of the side track groove, and a tapered back side track groove that becomes shallower from the opening side toward the back side. The second track groove of the member has an opening side track groove provided at an equal distance from the joint center in the axial direction from the joint center to the opening side opposite to the curvature center of the inner side track groove of the outer member, and 2. The fixed type constant velocity universal joint according to claim 1, further comprising a back side track groove having a center of curvature provided on the outer diameter side of the ball center.   3. The fixed type constant velocity free according to claim 1, wherein all or part of the first track groove and the second track groove of at least one of the outer member and the inner member are finished by forging. Fittings.

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