JP6890485B2 - Fixed constant velocity universal joint - Google Patents

Description

The present invention relates to a fixed constant velocity universal joint.

The constant-velocity universal joints that make up the power transmission system of automobiles and various industrial machines connect the two shafts on the drive side and the driven side so that torque can be transmitted, and transmit the rotational torque at a constant speed even if the two shafts have an operating angle. can do. Constant velocity universal joints are roughly classified into fixed constant velocity universal joints that allow only angular displacement and sliding constant velocity universal joints that allow both angular displacement and axial displacement. For example, from automobile engines. In the drive shaft that transmits power to the drive wheels, a sliding constant velocity universal joint is used on the differential side (inboard side), and a fixed constant velocity universal joint is used on the drive wheel side (outboard side). The wheel.

As a fixed constant velocity universal joint, a zepper type constant velocity universal joint and an undercut-free constant velocity universal joint are known. In recent years, there is also an 8-ball type zeppa type constant velocity universal joint that is both lightweight and compact, and various fixed constant velocity universal joints are used according to the purpose.

In order to increase the load capacity compared to the above-mentioned fixed constant velocity universal joint, a fixed constant velocity universal joint in which two adjacent pairs of track grooves are formed on a plane parallel to each other has been proposed. Patent Document 1).

Japanese Patent No. 4969758

In order to make the fixed constant velocity universal joint lightweight and compact, it is necessary to secure the strength of each component, and in particular, to secure the strength of the inner joint member and the cage. In the Zepper type constant velocity universal joint and the undercut free type constant velocity universal joint, when assembling, the angle (built-in angle) is set beyond the used area to insert the ball into the track groove, and the angle of the ball and the cage is increased. It is necessary to set the circumferential length of the cage pocket so that it does not interfere with each other. Since the circumferential length of the cage pocket does not change even if it is made compact, the pillar portion of the cage becomes thin, and it becomes difficult to secure the strength of the cage.

Further, in order to reduce the weight and size, it is necessary to reduce the pitch circle diameter PCD of the ball, but the contact surface pressure between the ball and the track groove increases. As a means for suppressing the contact surface pressure between the ball and the track groove to a certain level or less, it is conceivable to increase the ball diameter and increase the number of balls. However, when the means for increasing the ball diameter is applied, the spherical end portion of the inner joint member becomes thinner, and it becomes difficult to secure the strength of the inner joint member. Further, when the means for increasing the number of balls is applied, the number of pockets of the cage is increased, so that the pillar portion of the cage becomes thin, and it becomes more difficult to secure the strength of the cage.

As a solution to this problem, in the constant velocity universal joint of Patent Document 1, two adjacent track grooves are formed on a plane parallel to each other so that two adjacent balls can be stored in one pocket of a cage. By arranging the cage in, the pillar portion of the cage can be made thicker, and the wall thickness of the end portion of the spherical outer peripheral surface of the inner joint member is secured to improve the strength.

However, in the shape in which two adjacent track grooves paired are formed on a plane parallel to each other as in the constant velocity universal joint of Patent Document 1, the paired balls on one side (the number of balls) in the normal angle range. Since the torque can be transmitted only by half of the ball), the contact surface pressure between the ball and the track groove increases, and the durability decreases. The present invention focuses on this problem.

In view of the above problems, an object of the present invention is to provide a lightweight and compact fixed constant velocity universal joint capable of ensuring a large load capacity even in a normal angle range.

As a result of various studies to achieve the above object, the present inventors have arranged three pairs of first track grooves arranged on a plane parallel to the radial plane and three pairs of first track grooves arranged on the radial plane. The present invention was derived from the idea that the first track groove and the second track groove are arranged so as to face each other in the radial direction, which is composed of three second track grooves.

As a technical means for achieving the above-mentioned object, the present invention includes an outer joint member having a plurality of track grooves extending in the longitudinal direction on a spherical inner peripheral surface and having an opening side and a back side separated in the axial direction. An inner joint member having a plurality of track grooves extending in the longitudinal direction on the spherical outer peripheral surface facing the track groove of the outer joint member, a torque transmission ball incorporated between the facing track grooves, and the torque thereof. holding the transmission balls, in the outer joint spherical inner peripheral face of the fixed type constant velocity universal joint comprising a cage guided on the spherical outer peripheral surface of the inner joint member of the member, the track grooves 7 of the outer joint member , It is composed of three pairs of first track grooves 7A and 7B arranged at equal intervals in the circumferential direction and three second track grooves 7C, and is the track center of the first track grooves 7A and 7B. The lines X _A and X _B are arranged on the track groove planes B and B'that extend symmetrically and at intervals with respect to the radial plane A including the axis NN of the joint, and the second track groove 7C. the track center line X _C, the on radial plane a, and the first track groove 7A, is disposed at a position opposite to the pair of 7B diametrically, the first track groove 7A, 7B The track center lines X _A and X _B of the second track groove 7C have an arcuate portion whose center of curvature is offset in the axial direction of the outer joint member with respect to the projection center O'. X _C has an arcuate portion whose center of curvature is offset in the axial direction of the outer joint member with respect to the joint center O, and includes the joint center O in a state where the operating angle is 0 °, and the axis N- of the joint. and the plane P orthogonal to N, the first track groove 7A, raceway center line X _a of 7B, X _B and the intersections C _a of the track center line X _C of the second track groove 7C, C _B, C _C is arranged on one circle D in the plane P, and the track center line Y of the track groove 9 of the inner joint member is a pair of tracks of the outer joint member with reference to the plane P. It is characterized in that it is formed symmetrically with the orbital center line X of the groove 7.

With the above configuration, it is possible to realize a lightweight and compact fixed constant velocity universal joint that can secure a large load capacity even in the normal angle range.

The first track groove 7A to the above projection center O ', the track center line X _A of 7B, X raceway center line X _C of the second track groove 7C to the offset and the joint center O of the center of curvature of the arcuate portion of the _B It is desirable that the offset of the center of curvature of the arcuate portion of the above is provided toward the inner side of the outer joint member. As a result, the strength of the outer joint member at a high operating angle can be further improved.

_{The center of curvature of the track center lines X A} , X _B of the first track grooves 7A and 7B and the track center lines X _C of the second track groove 7C is offset in the radial direction with respect to the axis NN of the joint. It is preferable that it is. Thereby, the track groove depth at a high operating angle can be adjusted.

The first track groove 7A, 7B and the second track groove 7C have a high working angle track groove portion having a track center line having a shape different from the arcuate portion of the _{track center lines X A} , X _B , X _C. It is preferable to have 7Ab, 7Bb, and 7Cb on the opening side of the outer joint member. As a result, it is possible to form a track groove shape suitable for high operation.

_{The track center lines X Ab} , X _Bb , and X _Cb of the high operating angle track grooves 7Ab, 7Bb, and 7Cb are _{the track center lines X A} , X _B, and the second track groove 7C of the first track grooves 7A and 7B. It is preferable that the track has an arc shape that curves in the opposite direction to the arc shape portion of the track center line X _C. As a result, it is possible to form a track groove shape suitable for increasing the operating angle.

The cage has a pocket for accommodating two torque transmission balls incorporated in the first track grooves 7A and 7B of each pair, thereby increasing the width of the column portion of the cage to increase the strength. Can be improved.

According to the present invention, it is possible to realize a lightweight and compact fixed constant velocity universal joint that can secure a large load capacity even in a normal angle range.

The fixed constant velocity universal joint according to the first embodiment of the present invention is shown, FIG. 2A is a vertical cross-sectional view taken along line A1-N of FIG. 2, and FIG. 2B is B1 of FIG. The vertical cross section along the −N'line is rotated 180 ° clockwise. It is a right side view of FIG. 1 (a). It is an exploded perspective view of the outer joint member, the cage, the ball and the inner joint member of FIG. 1 (a). It is explanatory drawing which shows the contact state between the track groove of an inner joint member, and a ball. A fixed constant velocity universal joint according to a second embodiment of the present invention is shown. FIG. 2A is a vertical sectional view taken along line A1-N of FIG. 2, and FIG. 2B is B1 of FIG. The vertical cross section along the −N'line is rotated 180 ° clockwise. A fixed constant velocity universal joint according to a third embodiment of the present invention is shown, FIG. 2A is a vertical cross-sectional view taken along line A1-N of FIG. 2, and FIG. 2B is B1 of FIG. The vertical cross section along the −N'line is rotated 180 ° clockwise. A fixed constant velocity universal joint according to a fourth embodiment of the present invention is shown, FIG. 2A is a vertical cross-sectional view taken along line A1-N of FIG. 2, and FIG. 2B is B1 of FIG. The vertical cross section along the −N'line is rotated 180 ° clockwise. A fixed constant velocity universal joint according to a fifth embodiment of the present invention is shown, FIG. 2A is a vertical cross-sectional view taken along line A1-N of FIG. 2, and FIG. 2B is B1 of FIG. The vertical cross section along the −N'line is rotated 180 ° clockwise. A fixed constant velocity universal joint according to a sixth embodiment of the present invention is shown. FIG. 2A is a vertical sectional view taken along line A1-N of FIG. 2, and FIG. 2B is B1 of FIG. The vertical cross section along the −N'line is rotated 180 ° clockwise.

The fixed constant velocity universal joint according to the first embodiment of the present invention will be described with reference to FIGS. 1 to 4. 1 (a) is a vertical cross-sectional view taken along the line A1-N of FIG. 2, and FIG. 1 (b) is a vertical cross-sectional view taken along the line B1-N'of FIG. 2 rotated by 180 ° clockwise. It was made to do. FIG. 2 is a right side view of FIG. 1 (a), and FIG. 3 is an exploded perspective view of the outer joint member, the cage, the ball, and the inner joint member as viewed from the upper right side of FIG. 1 (b). FIG. 4 is an explanatory view showing a contact state between the track groove of the inner joint member and the ball.

As shown in FIGS. 1A to 2, the fixed constant velocity universal joint 1 of the present embodiment includes an outer joint member 2, an inner joint member 3, a torque transmission ball (simply also referred to as a ball) 4, and a cage. 5 is the main configuration. As shown in FIG. 2, three pairs of first track grooves 7A1, 7B1, 7A2, 7B2, 7A3, 7B3 and three second track grooves 7C1, 7C2 are formed on the spherical inner peripheral surface 6 of the outer joint member 2. , 7C3, a total of nine track grooves are formed in the longitudinal direction. On the spherical outer peripheral surface 8 of the inner joint member 3, three pairs of first track grooves 9A1, 9B1, 9A2, which face the first track grooves 7A1, 7B1, 7A2, 7B2, 7A3, 7B3 of the outer joint member 2, 9B2, 9A3, 9B3 and three second track grooves 9C1, 9C2, 9C3 facing the second track grooves 7C1, 7C2, 7C3 of the outer joint member 2, a total of nine track grooves 9 in the longitudinal direction. It is formed. Nine balls 4 for transmitting torque are incorporated one by one between the track groove 7 of the outer joint member 2 and the track groove 9 of the inner joint member 3.

Here, in the present specification and claims, when the first track grooves 7A1, 7B1, 7A2, 7B2, 7A3, 7B3 and the second track grooves 7C1, 7C2, 7C3 of the outer joint member 2 are collectively referred to. Reference numeral 7 is used, and reference numeral 9 is used when the first track grooves 9A1, 9B1, 9A2, 9B2, 9A3, 9B3 and the second track grooves 9C1, 9C2, 9C3 of the inner joint member 3 are collectively referred to. Further, when the first track grooves 7A1, 7A2, 7A3 and 7B1, 7B2, 7B3 of the outer joint member 2 are collectively referred to, reference numerals 7A and 7B are used, and the second track grooves 7C1, 7C2 and 7C3 are collectively referred to. When this is done, reference numeral 7C is used. The same procedure applies to the inner joint member 3.

As shown in FIGS. 1A and 1B, a cage 5 for holding the ball 4 is arranged between the spherical inner peripheral surface 6 of the outer joint member 2 and the spherical outer peripheral surface 8 of the inner joint member 3. Has been done. The ball 4 is housed in the pocket 5a of the cage 5. The spherical outer peripheral surface 12 of the cage 5 is slidably fitted to the spherical inner peripheral surface 6 of the outer joint member 2, and the spherical inner peripheral surface 13 of the cage 5 slides on the spherical inner peripheral surface 8 of the inner joint member 3. It fits freely and is guided.

As shown in FIG. 2, the three pairs of first track grooves 7A and 7B of the outer joint member 2 are the first pair of track grooves 7A1, 7B1, the second pair of track grooves 7A2, 7B2 and the third. It is composed of a pair of track grooves 7A3 and 7B3. Similarly, the three pairs of first track grooves 9A, 9B of the inner joint member 3 are the first pair of track grooves 9A1, 9B1, the second pair of track grooves 9A2, 9B2, and the third pair of track grooves. It is composed of 9A3 and 9B3.

The first track grooves 7A and 7B of the outer joint member 3 will be described. Of the three pairs of first track grooves 7A and 7B, the first pair of track grooves 7A1 and 7B1 are spaced on both sides of the radial plane A1 including the axis NN of the joint [see FIG. 1 (a)]. It is arranged symmetrically with respect to the radial plane A1. That is, the track center line X _A of the track groove 7A1 of the first pair [refer to FIG. 1 (b)] is placed on the track groove plane B1 extending in parallel with a distance from the radial plane A1, the track groove 7B1 The orbital center line X _B (not shown) is arranged on the track groove plane B'1 extending in parallel with the track groove plane B1 on the opposite side of the radial plane A1. The track groove plane B1 and the track groove plane B'1 are symmetrical with respect to the radial plane A1.

The second pair of track grooves 7A2, 7B2 are spaced apart from each other on both sides of the radial plane A2, which includes the axis NN of the joint and is at an angle of 120 ° clockwise with respect to the radial plane A1. , Are formed symmetrically with respect to the radial plane A2. _{The track center line X A} (not shown) of the second pair of track grooves 7A2 is arranged on the track groove plane B2 extending parallel to the radial plane A2 at intervals, and the track center line X _{B of the track groove 7B2.} (Not shown) is arranged on the track groove plane B'2 which extends parallel to the radial plane A2 on the side opposite to the track groove plane B2 at intervals. The track groove plane B2 and the track groove plane B'2 are also symmetrical with respect to the radial plane A2.

The third pair of track grooves 7A3, 7B3 are spaced apart from each other on both sides of the radial plane A3, which includes the axis NN of the joint and is at an angle of 240 ° clockwise with respect to the radial plane A1. , Are formed symmetrically with respect to the radial plane A3. _{The track center line X A} (not shown) of the third pair of track grooves 7A3 is arranged on the track groove plane B3 extending parallel to the radial plane A3 at intervals, and the track center line X _{B of the track groove 7B3.} (Not shown) is arranged on the track groove plane B'3 which extends parallel to the radial plane A3 on the side opposite to the track groove plane B3 at intervals. The track groove plane B3 and the track groove plane B'3 are also symmetrical with respect to the radial plane A3.

The axial shapes of the first track grooves 7A and 7B of the outer joint member 2 will be described with reference to FIG. 1 (b). Here, among the first track grooves 7A and 7B, the illustrated first track groove 7A1 will be described. The first track groove 7A1 is composed of an arcuate reference track groove 7A1a and a high operating angle track groove 7A1b. _{The track center line X Aa} of the reference track groove portion 7A1a is offset in the axial direction (offset amount f1) toward the inner side of the outer joint member 2 with respect to the projection center O'and is offset in the radial direction (offset amount f2). ) Is formed in an arc shape having a center of curvature O1. By providing an offset in the radial direction, the track groove depth at a high operating angle can be adjusted. Here, the projection center O'means a point where the joint center O located on the NN line is projected horizontally on the N'-N' line. Therefore, the axial positions of the projection center O'and the joint center O are the same. The relationship between the projection center O'and the joint center O is the same for the first track grooves 9A and 9B of the inner joint member 3. Further, the track center line X _Aa of the reference track groove portion 7A1a means an arc-shaped portion of _{the track center lines X A} and X _B of the first track grooves 7A and 7B in the claims.

_{The track center line X Ab} of the high working angle track groove portion 7A1b is offset in the axial direction (offset amount f3) toward the opening side of the outer joint member 2 with respect to the projection center O'and is offset in the radial direction (offset). It is formed in an arc shape having a center of curvature O2 with an amount f4). _{The track center line X Ab} of the high working angle track groove 7A1b _{and the track center line X Aa} of the reference track groove 7A1a are smoothly connected to each other on a straight line passing through the center of curvature O1 and O2 during curvature, although not shown. .. This connection point is located on the opening side of the outer joint member 2 with respect to the projection center O'. As described above, the first track groove 7A1 has a high working angle track groove portion 7A1b having a track center line X _{Ab having a shape different from the track center line X Aa} of the reference track groove portion 7A1a forming an arc-shaped portion, and the outer joint member 2 It has on the opening side of. _{Specifically, the track center line X Ab} of the high operating angle track groove portion 7A1b has an arc shape that curves on the opposite side of the arc shape portion of the track center line X _{Aa of the reference track groove portion 7A1a.} As a result, it is possible to form a track groove shape suitable for high operation.

When the joint has a high working angle, the ball 4 on the bisector plane is located in the high working angle track groove 7A1b. The operating angle when the ball 4 shifts from the reference track groove portion 7A1a to the high operating angle track groove portion 7A1b is preferably set to about 10 ° to 15 °, which exceeds the normal angle range.

The second track groove 7C of the outer joint member 2 will be described. As shown in FIG. 2, the second track groove 7C is composed of three track grooves 7C1, 7C2, and 7C3. Raceway center line X _C of the second track groove 7C1 [shown in Fig. 1 (a) is disposed on a radial plane A1 containing the axis N-N of the joint, and track of the first track groove 7A1,7B1 It is arranged at a position facing the center line X _A and X _B (X _B is not shown) in the radial direction.

Raceway center line X _C of the second track groove 7C2 (not shown) includes a joint axial line N-N, arranged on a radial plane A2 forming an angle of 120 ° in the clockwise direction with respect to a radial plane A1 It is, and the track center lines X _a of the first track groove 7A2,7B2, are disposed at positions diametrically opposite with respect to the pair of X _B (not shown).

Raceway center line X _C of the second track groove 7C3 (not shown) includes a joint axial line N-N, arranged on a radial plane A3 forming an angle of 240 ° in the clockwise direction with respect to a radial plane A1 The first track grooves 7A3 and 7B3 are arranged at positions facing each other in the radial direction with respect to the pair _{of track center lines X A} and X _{B (not shown).}

The axial shape of the second track groove 7C will be described with reference to FIG. 1 (a). Here, among the second track grooves 7C, the illustrated second track groove 7C1 will be described. Like the first track groove 7A1, the second track groove 7C1 is also composed of an arcuate reference track groove portion 7C1a and a high operating angle track groove portion 7C1b. _{The track center line X Ca} of the reference track groove portion 7C1a is axially offset (offset amount f5) toward the inner side of the outer joint member 2 with respect to the joint center O, and is offset in the radial direction (offset amount f6). It is formed in an arc shape having a curved center O5.

_{The track center line X Cb} of the high working angle track groove portion 7C1b is offset in the axial direction (offset amount f7) toward the opening side of the outer joint member 2 with respect to the joint center O, and is offset in the radial direction (offset amount). It is formed in an arc shape having an offset center O6 (f8). _{The track center line X Cb} of the high working angle track groove 7C1b _{and the track center line X Ca} of the reference track groove 7C1a are smoothly connected on a straight line passing through the center of curvature O5 and the center of curvature O6, although not shown. .. This connection point is located on the opening side of the outer joint member 2 with respect to the joint center O. As described above, the second track groove 7C1 has a high working angle track groove portion 7C1b having a track center line X _{Cb having a shape different from the track center line X Ca} of the reference track groove portion 7C1a forming an arc-shaped portion, and the outer joint member 2 It has on the opening side of. _{Specifically, the track center line X Cb} of the high operating angle track groove portion 7C1b has an arc shape that curves on the opposite side of the arc shape portion of the track center line X _{Ca of the reference track groove portion 7C1a.} As a result, it is possible to form a track groove shape suitable for high operation.

When the joint has a high working angle, the ball 4 on the bisector plane is located in the high working angle track groove 7C1b. The operating angle when the ball 4 in the second track groove 7C1 shifts from the reference track groove portion 7C1a to the high working angle track groove portion 7C1b is the same as the shifting operating angle of the first track groove 7A1b. Further, the transition operating angle is the same for the inner joint member 3 described later.

Next, the first track grooves 9A and 9B of the inner joint member 3 will be described. As shown in FIG. 2, of the three pairs of first track grooves 9A and 9B of the inner joint member 3, the first pair of track grooves 9A1 and 9B1 are radial planes A1 including the axis NN of the joint. They are arranged at intervals on both sides of the above, and are formed symmetrically with respect to the radial plane A1. That is, the track center line Y _A of the track groove 9A1 of the first pair [refer to FIG. 1 (b)] is placed on the track groove plane B1 extending in parallel with a distance from the radial plane A1, the track groove 9B1 The orbital center line Y _B (not shown) is arranged on the track groove plane B'1 extending in parallel with the track groove plane B1 on the opposite side of the radial plane A1. As described above, the track groove plane B1 and the track groove plane B'1 are symmetrical with respect to the radial plane A1.

The second pair of track grooves 9A2, 9B2 are spaced apart from each other on both sides of the radial plane A2, which includes the axis NN of the joint and is at an angle of 120 ° clockwise with respect to the radial plane A1. , Are formed symmetrically with respect to the radial plane A2. Raceway center line Y _A of the track groove 9A2 of the second pair (not shown) may have a distance from the radial plane A2 is arranged on the track groove plane B2 extending in parallel, the track center line Y _B of the track groove 9B2 (Not shown) is arranged on the track groove plane B'2 which extends parallel to the radial plane A2 on the side opposite to the track groove plane B2 at intervals. As described above, the track groove plane B2 and the track groove plane B'2 are symmetrical with respect to the radial plane A2.

The third pair of track grooves 9A3, 9B3 are spaced apart from each other on both sides of the radial plane A3, which includes the axis NN of the joint and is at an angle of 240 ° clockwise with respect to the radial plane A1. , Are formed symmetrically with respect to the radial plane A3. Third raceway center line of the track grooves 9A3 pair Y _A (not shown) may have a distance from the radial plane A3 is disposed on the track groove plane B3 extending in parallel, the track center line Y _B of the track groove 9B3 (Not shown) is arranged on the track groove plane B'3 which extends parallel to the radial plane A3 on the side opposite to the track groove plane B3 at intervals. As described above, the track groove plane B3 and the track groove plane B'3 are symmetrical with respect to the radial plane A3.

The axial shapes of the first track grooves 9A and 9B of the inner joint member 3 will be described with reference to FIG. 1 (b). Here, among the first track grooves 9A and 9B, the illustrated first track groove 9A1 will be described. The first track groove 9A1 is composed of an arc-shaped reference track groove 9A1a and a high operating angle track groove 9A1b. _{The track center line Y Aa} of the reference track groove portion 9A1a is offset in the axial direction (offset amount f1) toward the opening side of the outer joint member 2 with respect to the projection center O'and is offset in the radial direction (offset amount f2). ) Is formed in an arc shape having a center of curvature O3.

_{The track center line Y Ab} of the high working angle track groove portion 9A1b is offset in the axial direction (offset amount f3) toward the inner side of the outer joint member 2 with respect to the projection center O'and is offset in the radial direction (offset). It is formed in an arc shape having an offset center O4 (amount f4). _{The track center line Y Ab} of the high working angle track groove 9A1b _{and the track center line Y Aa} of the reference track groove 9A1a are smoothly connected on a straight line passing through the center of curvature O3 and the center of curvature O4, although not shown. .. This connection point is located on the inner side of the outer joint member 2 with respect to the projection center O'. As described above, the first track groove 9A1 has a high working angle track groove 9A1b having a track center line Y _{Ab having a shape different from the track center line Y Aa} of the reference track groove 9A1a forming an arc-shaped portion, and the outer joint member 2 It is held on the back side of. _{Specifically, the track center line Y Ab} of the high operating angle track groove portion 9A1b has an arc shape that curves on the opposite side of the arc shape portion of the track center line Y _{Aa of the reference track groove portion 9A1a.} When the joint has a high working angle, the ball 4 on the bisector plane is located in the high working angle track groove 9A1b.

The second track groove 9C of the inner joint member 2 will be described. As shown in FIG. 2, the second track groove 9C is composed of three track grooves 9C1, 9C2, and 9C3. Raceway center line Y _C of the second track groove 9C1 [shown in Fig. 1 (a) is disposed on a radial plane A1 containing the axis N-N of the joint, and track of the first track groove 9A1,9B1 It is arranged at a position facing the center line Y _A and Y _B (Y _B is not shown) in the radial direction.

The track center line Y _C (not shown) of the second track groove 9C2 includes the axis line NN of the joint and is arranged on the radial plane A2 at an angle of 120 ° clockwise with respect to the radial plane A1. The first track grooves 9A2 and 9B2 are arranged at positions facing each other in the radial direction with respect to a pair _{of track center lines Y A} and Y _{B (not shown).}

The track center line Y _C (not shown) of the second track groove 9C3 includes the axis line NN of the joint and is arranged on the radial plane A3 at an angle of 240 ° clockwise with respect to the radial plane A1. The first track grooves 9A3 and 9B3 are arranged at positions facing each other in the radial direction with respect to a pair _{of track center lines Y A} and Y _{B (not shown).}

The axial shape of the second track groove 9C of the inner joint member 3 will be described with reference to FIG. 1A. As in the case of the outer joint member 2 described above, the second track groove 9C1 shown in the second track groove 9C will be described. Like the first track groove 9A1, the second track groove 9C1 is also composed of an arcuate reference track groove portion 9C1a and a high operating angle track groove portion 9C1b. _{The track center line Y Ca} of the reference track groove 9C1a is axially offset (offset amount f5) toward the opening side of the outer joint member 2 with respect to the joint center O, and is offset in the radial direction (offset amount f6). It is formed in an arc shape having a curved center O7.

_{The track center line Y Cb} of the high operating angle track groove portion 9C1b is offset in the axial direction (offset amount f7) toward the inner side of the outer joint member 2 with respect to the joint center O, and is offset in the radial direction (offset amount). It is formed in an arc shape having an offset center O8 (f8). _{The track center line Y Cb} of the high working angle track groove 9C1b _{and the track center line Y Ca} of the reference track groove 9C1a are smoothly connected on a straight line passing through the center of curvature O7 and the center of curvature O8, although not shown. .. This connection point is located on the inner side of the outer joint member 2 with respect to the joint center O. As described above, the second track groove 9C1 has a high working angle track groove 9C1b having a track center line Y _{Cb having a shape different from the track center line Y Ca} of the reference track groove 9C1a forming an arcuate portion, and the outer joint member 2 It is held on the back side of. _{Specifically, the track center line Y Cb} of the high operating angle track groove portion 9C1b has an arc shape that curves on the opposite side of the arc shape portion of the track center line Y _{Ca of the reference track groove portion 9C1a.} When the joint has a high working angle, the ball 4 on the bisector plane is located in the high working angle track groove 9C1b.

Axial shapes of the first track grooves 7A, 7B, the second track groove 7C of the outer joint member 2, and the first track grooves 9A, 9B, and the second track groove 9C of the inner joint member 3. In the description thereof, specific track grooves 7A1, 7C1, 9A1, and 9C1 have been described as an example in order to make the consistency with the drawings accurate, but the content thereof is the same for other track grooves. That is, of the three pairs of first track grooves 7A1, 7B1, 7A2, 7B2, 7A3, and 7B3 of the outer joint member 2, the first track grooves 7A1, 7A2, and 7A3 have the same shape as each other, and the first track. The grooves 7B1, 7B2, and 7B3 have the same shape. The first track grooves 7A1 and 7B1 are symmetric with respect to the radial plane A1, the first track grooves 7A2 and 7B2 are symmetric with respect to the radial plane A2, and the radial plane A3 is used as a reference. The first track grooves 7A3 and 7B3 are symmetrical. Therefore, except for the relationship that the first track grooves 7A1, 7A2, 7A3 and the first track grooves 7B1, 7B2, 7B3 are symmetrical with respect to the radial planes A1, A2, A3, each track groove The shapes of 7A and 7B are the same. Of course, the second track grooves 7C1, 7C2, and 7C3 have the same shape. Therefore, the above-described description of the specific track grooves 7A1, 7C1, 9A1, and 9C1 can be similarly applied to the other track grooves of the outer joint member 2 and the inner joint member 3. The same shall apply in the subsequent embodiments.

_{When the track center lines X A} , X _B , X _C , X _Aa , X _Ab , X _Ca , and X _Cb of the track groove 7 of the outer joint member 2 are collectively referred to, the reference numeral X is used and the track groove of the inner joint member 3 is used. When the orbital center lines Y _A , Y _B , Y _C , Y _Aa , Y _Ab , Y _Ca , and Y _{Cb of 9} are collectively referred to, the reference numeral Y is used.

The offset amounts f1 to f8 indicating the positions of the center lines of curvature of the track center line X of the track groove 7 of the outer joint member 2 and the track center line Y of the track groove 9 of the inner joint member 3 described above are designated by the same reference numerals. The amount of offset means that the dimensions are equal to each other. The same shall apply in the subsequent embodiments.

The form of each track groove of the outer joint member 2 and the inner joint member 3 has been described above. However, the track center line Y of the track groove 9 of the inner joint member 3 includes the joint center O in a state where the operating angle is 0 °. It is formed symmetrically with the track center line X of the track groove 7 paired with the outer joint member 2 with reference to the plane P [see FIGS. 1 (a) and 1 (b)] orthogonal to the axis NN of the outer joint member 2. ing.

FIG. 3 shows an exploded perspective view of the outer joint member 2, the cage 5, the ball 4, and the inner joint member 3 of the fixed constant velocity universal joint 1 of the present embodiment as viewed from the upper right side of FIG. 1 (b). FIG. 3 shows a state in which the ball 4 is housed in the pocket 5a of the cage 5.

The first track groove 7A paired, 7B, 9A, raceway center line X _A of 9B, X _B, Y _A, since the circumferential distance between Y _B (not shown) is set small, in FIG. 3 As shown, while suppressing the circumferential length of the pocket 5a1 of the cage 5, the two balls 4 incorporated in the paired first track grooves 7A, 7B, 9A, 9B are put into one pocket 5a1. Can be accommodated. As a result, the width of the pillar portion 5b of the cage 5 can be increased to improve the strength. The balls 4 incorporated in the second track grooves 7C and 9C are housed one by one in the pockets 5a2.

_{Here, the reason why the circumferential distance between the track center lines X A} , X _B , Y _A , and Y _B of the paired first track grooves 7A, 7B, 9A, and 9B can be set to be small will be described. As described above, the first track groove 7A of the outer joint member 2 and the inner joint member 3, 7B, 9A, 9B of the track center line _{X A, X B, Y A} , Y B , the track groove plane B1, B It is arranged on '1, B2, B'2, B3, and B'3. As described above, the track groove planes B1 and B'1 are formed parallel to the radial plane A1, the planes B2 and B'2 are formed parallel to the radial plane A2, and the track groove planes B3 and B'3 are formed. It is formed parallel to the radial plane A3. That is, the first track groove 7A, 7B, 9A, 9B of the track center line _{X A, X B, Y A} , Y B is a radial plane A1 or radial plane A2, are formed parallel to the radial plane A3 ing. Therefore, the wall thickness of the rib portion 3a (see FIG. 2) between the track grooves 9A and 9B at the end of the inner joint member 3, which is particularly related to ensuring the strength at a high angle, does not decrease, and the track groove 9 and the inside thereof do not decrease. The minimum wall thickness with the peripheral hole (connecting hole with the intermediate shaft) increases. Therefore, the circumferential distance between the _{track center lines X A} , X _B , Y _A , and Y _{B of} the paired first track grooves 7A, 7B, 9A, and 9B can be set small.

The torque load characteristics of the fixed constant velocity universal joint 1 of the present embodiment will be described with reference to FIG. FIG. 4 shows a contact state between the track groove 9 of the inner joint member 3 and the ball 4 in a state where the operating angle is 0 °. The first track grooves 9A and 9B and the ball 4 are in contact with the track groove planes B and B'with a contact angle α, and the second track groove 9C and the ball 4 are in contact with the radial plane A at a contact angle. They are in contact with α.

A plane P [see FIGS. 1 (a) and 1 (b)] including the joint center O at an operating angle of 0 ° and orthogonal to the axis NN of the joint, and a first track groove of the outer joint member 2. 7A, raceway center line X _a of 7B, X _B and the intersection of the raceway center line X _C of the second track groove. 7C, C _a, C _B shown in FIG. 4, the C _C. The intersections C _A , C _B , and C _C are arranged on one circle D in the plane P. In other words, as shown in FIG. 4, nine balls 4, 4', 4 "that transmit torque are arranged on the same circumference in the plane P, and the torque is evenly shared by each ball. However, in the actual product, there is only a small amount between the balls 4, 4'4 "and the track grooves 7A, 7B, 7C of the outer joint member 2 and the track grooves 9A, 9B, 9C of the inner joint member 3. There is a gap. Here, a plane P including the joint center O and orthogonal to the axis NN of the joint at an operating angle of 0 ° in the present specification and claims, and the track center lines X of the first track grooves 7A and 7B. _{The configuration in} which the intersections C _A , C _B , and C _{C of} A, X _B, and the second track groove 7 C with the orbital center line X _C are arranged on one circle D on the plane P is described above. Used in the sense of including a concept.

In the first track grooves 9A1 and 9B1, the ball 4 on one side of the paired track grooves 9A1 and 9B1 transmits most of the torque. Specifically, in the track groove 9B1, when the inner joint member 3 is rotated in the direction of the white arrow and a torque is applied, the torque transmission direction vector f'generated in the ball 4'on the track groove plane B'1 The contact direction vector b'of the ball 4'and the track groove 9B1 intersect at a large angle, that is, in a state close to a straight line. On the other hand, the torque transmission direction vector f generated in the ball 4 on the track groove plane B1 and the contact direction vector b of the track groove 9A1 intersect at a small angle, that is, in a bent state. Therefore, of the pair of track grooves 9A1 and 9B1, the ball 4'of the track groove 9B1 transmits most of the torque, and the ball 4 of the track groove 9A1 can hardly transmit torque. This state is the same for the second pair of track grooves 9A2 and 9B2 and the third pair of track grooves 9A3 and 9B3. In this way, the balls 4'on one side of the three pairs of first track grooves 9A and 9B (three balls, which are half of the six) transmit most of the torque, and the balls 4 on the other side transmit most of the torque. I can't communicate. This state is the same when torque is applied in the direction opposite to the white arrow. That is, the torque transmitting 4 and 4'changes, and of the pair of track grooves 9A1 and 9B1, the ball 4 of the track groove 9A1 transmits most of the torque, and the ball 4'of the track groove 9B1 can hardly transmit torque. become.

In the second track groove 9C, all three balls 4 "transmit torque to the first track groove 9A and 9B described above. Specifically, the second track groove 9C and the ball 4 Is in contact with the radial plane A with a contact angle α. The torque transmission direction vector f "generated on the ball 4" on the radial plane A1 and the contact direction vector b "of the ball 4" and the track groove 9C1 intersect at a large angle. Although not shown, the other track grooves 9C2 and 9C3 are in the same state. Therefore, when the inner joint member 3 is rotated in the direction of the white arrow and a torque is applied, all of the three balls 4 "of the track groove 9C can transmit the torque, which is the opposite of the white arrow. The same applies when torque is applied in the direction.

The contact state between the track groove 7 and the ball 4 of the outer joint member 2 and the torque load characteristic are not shown, but are the same as the contact state between the track groove 9 and the ball 4 of the inner joint member 2 and the torque load characteristic described above. Is.

As described above, in the fixed constant velocity universal joint 1 of the present embodiment, the track grooves 7 and 9 have three pairs of the first track grooves 7A, 9A, 7B and 9B and the three second track grooves 7C. Since it is composed of 9C, there are always three balls 4 (or 4') of the first track grooves 7A, 9A, 7B and 9B and three balls 4 of the second track grooves 7C and 9C. Torque is transmitted by a total of 6 balls, and as described above, by arranging 9 balls 4, 4', 4 "on the same circumference on the plane P, the torque is shared more evenly. It is possible to secure the load capacity and durability even in the normal angle range.

The second track groove 7C, 9C raceway center line Xc of, Y _C is the first track groove 7A, 7B, 9A, raceway center line X _A of 9B, X _B, Y _A, a pair of Y _B On the other hand, since they are arranged at positions facing each other in the radial direction, the track load in the high operating angle region is suppressed, and the ball at the open end of the track groove 7 of the outer joint member 2 at an ultra-high operating angle exceeding 50 °. 4 has smooth entry and exit, and is suitable as a fixed constant velocity universal joint for ultra-high working angles.

Next, the fixed constant velocity universal joint according to the second embodiment of the present invention will be described with reference to FIGS. 5 (a) and 5 (b). Since the cross section of the fixed constant velocity universal joint of the present embodiment is substantially the same as that of FIG. 2 of the first embodiment, FIG. 2 is applied mutatis mutandis. The same shall apply to the fixed constant velocity universal joint according to the subsequent embodiments. 5 (a) is a vertical cross-sectional view taken along the line A1-N of FIG. 2, and FIG. 5 (b) is a vertical cross-sectional view taken along the line B1-N'of FIG. 2 rotated by 180 ° clockwise. It was made to do.

The fixed constant velocity universal joint 1 of the present embodiment is located at the center of curvature of the track center line of the reference track grooves 7 and 9 of the outer joint member 2 and the inner joint member 3 with respect to the first embodiment. Is different. In the present embodiment, the center of curvature of the track center line of the reference track groove is located on the axis NN of the joint and on the N'-N'line, and there is no radial offset. Since the other configurations are the same as those in the first embodiment, the parts having the same functions are designated by the same reference numerals. The contents described in the first embodiment will be applied mutatis mutandis, and the differences will be described. The same shall apply to the subsequent embodiments.

_{As shown in FIG. 5B, in the present embodiment, the track center line X Aa} of the reference track groove portion 7A1a of the first track groove 7A1 of the outer joint member 2 is the projection center O'on the N'-N'line. It has a center of curvature O1 _{1 offset (offset amount f1 1} ) toward the inner side of the outer joint member 2. _{The track center line Y Aa} of the reference track groove portion 9A1a of the first track groove 9A1 of the inner joint member 3 is offset toward the opening side of the outer joint member 2 with respect to the projection center O'on the N'-N'line. It has a center of curvature O3 ₁ with an offset amount f1 _1). Neither the center of curvature O1 ₁ nor O3 ₁ is provided with an offset in the radial direction.

_{As shown in FIG. 5A, the track center line X Ca} of the reference track groove portion 7C1a of the second track groove 7C1 of the outer joint member 2 is the outer joint with respect to the joint center O on the axis line NN of the joint. It has a center of curvature O5 _{1 offset (offset amount f5 1} ) toward the back side of the member 2. _{The track center line Y Ca} of the reference track groove portion 9C1a of the second track groove 9C1 of the inner joint member 3 is offset toward the opening side of the outer joint member 2 with respect to the joint center O on the axis line NN of the joint ( It has a center of curvature O7 ₁ with an offset amount f5 _1). The centers of curvature O 5 ₁ and O 7 ₁ are not provided with offsets in the radial direction.

The fixed constant velocity universal joint according to the third embodiment of the present invention will be described with reference to FIGS. 6 (a) and 6 (b). _{As shown in FIG. 6B, in the present embodiment, the track center line X Aa} of the reference track groove portion 7A1a of the first track groove 7A1 of the outer joint member 2 is the projection center O'on the N'-N'line. It is formed in an arc shape having a center of curvature O1 _{2 offset (offset amount f1 2} ) toward the inner side of the outer joint member 2. _{The track center line Y Aa} of the reference track groove portion 9A1a of the first track groove 9A1 of the inner joint member 3 is offset toward the opening side of the outer joint member 2 with respect to the projection center O'on the N'-N'line. It is formed in an arc shape having a center of curvature O3 ₂ with an offset amount f1 _2). Neither the center of curvature O1 ₂ nor O3 ₂ is provided with an offset in the radial direction.

High operating angle of the first track groove 7A1 of the outer joint member 2 The track center line X _Ab of the track groove portion 7A1b has an inclination angle β so as to approach the N'-N'line toward the opening side of the outer joint member 2. _{The track center line Y Ab} of the high working angle track groove portion 9A1b of the first track groove 9A1 of the inner joint member 3 which is formed in an inclined linear shape is an N'-N'line toward the inner side of the outer joint member 2. It is formed in a straight line inclined at an inclination angle β so as to approach. The inclination angle β is such that the operating angle when the ball 4 shifts from the reference track groove portions 7A1a and 9A1a to the high operating angle track groove portions 7A1b and 9A1b is about 10 ° to 15 °, which exceeds the normal angle range, as described above. Is set to. The inclination angle β is the same for the second track grooves 7C1 and 9C1 described later.

_{As shown in FIG. 6A, the track center line X Ca} of the reference track groove portion 7C1a of the second track groove 7C1 of the outer joint member 2 is the outer joint with respect to the joint center O on the axis line NN of the joint. is formed in an arc shape having an offset (offset amount f5 ₂₎ has been the center of curvature O5 ₂ toward the back side of the member 2. _{The track center line Y Ca} of the reference track groove portion 9C1a of the second track groove 9C1 of the inner joint member 3 is offset toward the opening side of the outer joint member 2 with respect to the joint center O on the axis line NN of the joint ( It is formed in an arc shape having a center of curvature O7 ₂ with an offset amount f5 _2). The centers of curvature O5 ₂ and O7 ₂ are not provided with offsets in the radial direction.

High operating angle of the second track groove 7C1 of the outer joint member 2 The track center line X _Cb of the track groove portion 7C1b has an inclination angle β so as to approach the axis line NN of the joint toward the opening side of the outer joint member 2. _{The track center line Y Cb} of the high working angle track groove portion 9C1b of the second track groove 9C1 of the inner joint member 3 is formed in an inclined linear shape, and the axis line NN of the joint is directed toward the inner side of the outer joint member 2. It is formed in a straight line inclined at an inclination angle β so as to approach.

The fixed constant velocity universal joint according to the fourth embodiment of the present invention will be described with reference to FIGS. 7 (a) and 7 (b). The fixed constant velocity universal joint 1 of the present embodiment is different from the first embodiment in that the track grooves 7 and 9 of the outer joint member 2 and the inner joint member 3 are not provided with high operating angle track grooves. .. As shown in FIG. 7B, in the present embodiment, the track center line X _Aa of the reference track groove portion 7A1a of the first track groove 7A1 of the outer joint member 2 is the outer joint member 2 with respect to the projection center O'. of toward the back side are offset (offset amount f1 _3), it is radially formed in an arc shape having a center of curvature O1 ₃ that is offset (offset amount f2 _3). Raceway center line Y _Aa of the reference track groove portion 9A1a of the first track groove 9A1 of the inner joint member 3 is offset toward the opening side of the outer joint member 2 relative to the projection center O '(the offset amount f1 _3), It is formed in an arc shape having a center of curvature O3 ₃ offset in the radial direction (offset amount f2 _{3). The track center lines X Aa} and Y _Aa of the reference track grooves 7A1a and 9A1a are formed in a uniform arc shape over the entire axial direction of the track grooves 7A1 and 9A1.

_{As shown in FIG. 7A, the track center line X Ca} of the reference track groove portion 7C1a of the second track groove 7C1 of the outer joint member 2 is directed toward the inner side of the outer joint member 2 with respect to the joint center O. are offset (offset amount f5 _3), it is formed in the offset (f6 ₃₎ is arcuate with a curvature center O5 ₃ in the radial direction. Raceway center line Y _Ca of the reference track groove portion 9C1a of the second track groove 9C1 of the inner joint member 3 is offset (offset amount f5 ₃₎ toward the opening side of the outer joint member 2 relative to the joint center O, radius It is formed in an arc shape having a center of curvature O7 ₃ that is offset (offset amount f6 ₃₎ in the direction. _{The track center lines X Ca} and Y _Ca of the reference track grooves 7C1a and 9C1a are formed in a uniform arc shape over the entire axial direction of the track grooves 7C1 and 9C1.

The fixed constant velocity universal joint according to the fifth embodiment of the present invention will be described with reference to FIGS. 8 (a) and 8 (b). In the fixed constant velocity universal joint 1 of the present embodiment, the center of curvature of the track center line of the reference track groove portions of the track grooves 7 and 9 of the outer joint member 2 and the inner joint member 3 is different from that of the fourth embodiment. The difference is that they are located on the axis NN and N'-N'of the joint and there is no radial offset. _{As shown in FIG. 8B, in the present embodiment, the track center line X Aa} of the reference track groove portion 7A1a of the first track groove 7A1 of the outer joint member 2 is the projection center O'on the N'-N'line. It is formed in an arc shape having a center of curvature O1 ₄ that is offset (offset amount f1 ₄₎ toward the inner side of the outer joint member 2 relative. _{The track center line Y Aa} of the reference track groove portion 9A1a of the first track groove 9A1 of the inner joint member 3 is offset toward the opening side of the outer joint member 2 with respect to the projection center O'on the N'-N'line. It is formed in an arc shape having a center of curvature O3 ₄ with an offset amount f1 _4).

_{As shown in FIG. 8A, the track center line X Ca} of the reference track groove portion 7C1a of the second track groove 7C1 of the outer joint member 2 is the outer joint with respect to the joint center O on the axis line NN of the joint. toward the back side of the member 2 is formed in an arc shape having a center of curvature O5 ₄ that is offset (offset amount f5 _{4). The track center line Y Ca} of the reference track groove portion 9C1a of the second track groove 9C1 of the inner joint member 3 is offset toward the opening side of the outer joint member 2 with respect to the joint center O on the axis line NN of the joint ( It is formed in an arc shape having a center of curvature O7 ₄ with an offset amount f5 _4).

The fixed constant velocity universal joint according to the sixth embodiment of the present invention will be described with reference to FIGS. 9 (a) and 9 (b). In the fixed constant velocity universal joint 1 of the present embodiment, the center of curvature of the track center line of the reference track groove portions of the track grooves 7 and 9 of the outer joint member 2 and the inner joint member 3 is different from that of the fourth embodiment. The difference is that they are offset downward in the radial direction with respect to the axis lines NN and N'-N'of the joint. As shown in FIG. 9B, in the present embodiment, the track center line X _Aa of the reference track groove portion 7A1a of the first track groove 7A1 of the outer joint member 2 is the outer joint member 2 with respect to the projection center O'. It is offset toward the the back side (the offset amount f1 _5), is formed in an arc shape having a center of curvature O1 ₅ that is offset (offset amount f2 ₅₎ radially lower side with respect N'-N 'line There is. Raceway center line Y _Aa of the reference track groove portion 9A1a of the first track groove 9A1 of the inner joint member 3 is offset toward the opening side of the outer joint member 2 relative to the projection center O '(the offset amount f1 _5), N'-N 'line is formed in an arc shape having a center of curvature O3 ₅ that is offset (offset amount f2 ₅₎ radially lower side with respect to.

_{As shown in FIG. 9A, the track center line X Ca} of the reference track groove portion 7C1a of the second track groove 7C1 of the outer joint member 2 is directed toward the inner side of the outer joint member 2 with respect to the joint center O. are offset (offset amount f5 _5), it is formed in an arc shape having a center of curvature O5 ₅ that is offset (offset amount f6 ₅₎ radially lower side with respect to the axis N-N of the joint. Raceway center line Y _Ca of the reference track groove portion 9C1a of the second track groove 9C1 of the inner joint member 3 is offset (offset amount f5 ₅₎ toward the opening side of the outer joint member 2 relative to the joint center O, the joint is formed in an arc shape having a center of curvature O7 ₅ that is offset (offset amount f6 ₅₎ radially lower side with respect to the axis N-N.

In summary, the fixed constant velocity universal joint 1 according to each of the above-described embodiments has three pairs of first track grooves 7A, 9A, 7B, 9B and three second tracks having track grooves 7 and 9. Since it is composed of grooves 7C and 9C, there are always three balls 4 (or 4') of the first track grooves 7A, 9A, 7B and 9B and three of the second track grooves 7C and 9C. Torque is transmitted by a total of 6 balls of the ball 4 ", and by arranging 9 balls 4, 4'4" on the same circumference on the plane P, the torque can be shared more evenly. It is possible to secure load capacity and durability even in the normal angle range. The second track groove 7C, 9C raceway center line Xc of, Y _C is the first track groove 7A, 7B, 9A, raceway center line X _A of 9B, X _B, Y _A, a pair of Y _B On the other hand, since they are arranged at positions facing each other in the radial direction, the track load in the high operating angle region is suppressed, and the ball at the open end of the track groove 7 of the outer joint member 2 at an ultra-high operating angle exceeding 50 °. 4 has smooth entry and exit, and is suitable as a fixed constant velocity universal joint for ultra-high working angles.

The present invention is not limited to the above-described embodiments, and it goes without saying that the present invention can be carried out in various forms without departing from the gist of the present invention. Indicated by the scope of the claim and further includes the equal meaning described in the claims, and all modifications within the scope.

1 Fixed constant velocity universal joint 2 Outer joint member 3 Inner joint member 4 Torque transmission ball 5 Cage 5a Pocket 6 Spherical inner peripheral surface 7 Track groove 7A First track groove 7Aa Reference track groove 7Ab High operating angle track groove 7B No. 1 track groove 7Ba Reference track groove 7Bb High operating angle track groove 7C Second track groove 7Ca Reference track groove 7Cb High operating angle track groove 8 Spherical outer surface 9 Track groove 9A First track groove 9Aa Reference track groove 9Ab High operation Square track groove 9B First track groove 9Ba Reference track groove 9Bb High operating angle track groove 9C Second track groove 9C Reference track groove 9Cb High operating angle track groove 12 Spherical outer peripheral surface 13 Spherical inner peripheral surface A Radial plane B Track Groove plane C _A Intersection C _B Intersection C _C Intersection D Circle N Joint axis O Joint center O'Projection center P Plane X Orbital centerline X _A Orbital centerline X _Aa Orbital centerline X _Ab Orbital centerline X _B Orbital centerline X _Ba Orbital Center Line X _Bb Orbital Center Line X _C Orbital Center Line X _Ca Orbital Center Line X _Cb Orbital Center Line Y Orbital Center Line Y _A Orbital Center Line Y _Aa Orbital Center Line Y _Ab Orbital Center Line Y _B Orbital Center Line Y _Ba orbital centerline Y _Bb orbital centerline Y _C orbital centerline Y _Ca orbital centerline Y _Cb orbital centerline

Claims (6)

A plurality of track grooves extending in the longitudinal direction are formed on the spherical inner peripheral surface, and an outer joint member having an opening side and a back side separated in the axial direction and a plurality of track grooves extending in the longitudinal direction on the spherical outer peripheral surface form the outer joint. The inner joint member formed so as to face the track groove of the member, the torque transmission ball incorporated between the opposite track grooves, and the spherical inner peripheral surface of the outer joint member and the spherical inner peripheral surface of the outer joint member are held. In a fixed constant velocity universal joint consisting of a cage guided to the spherical outer peripheral surface of the inner joint member
The track grooves (7) of the outer joint member are three pairs of first track grooves (7A) and (7B) and three second track grooves (7C) arranged at equal intervals in the circumferential direction. Consists of
_{The track center lines (X A} ) and (X _B ) of the first track grooves (7A) and (7B) are symmetrical with respect to the radial plane (A) including the axis (NN) of the joint. Arranged on track groove planes (B), (B') extending in parallel at intervals,
The second track groove track center line (7C) (X _C), the on radial plane (A), and the first track groove (7A), the diameter direction relative to the pair of (7B) Located in a position facing the
_{The center of curvature of the track center lines (X A} ) and (X _B ) of the first track grooves (7A) and (7B) is offset in the axial direction of the outer joint member with respect to the projection center (O'). Has an arc-shaped part
_{The track center line (X C} ) of the second track groove (7C) has an arcuate portion whose curvature center is offset in the axial direction of the outer joint member with respect to the joint center (O).
A plane (P) including the joint center (O) and orthogonal to the axis (NN) of the joint at an operating angle of 0 °, and the track center lines of the first track grooves (7A) and (7B). (X _a), one in the (X _B) and the second track groove track center line (7C) (X _C) the intersection of the _{(C a, C B, C} C) is, the plane (P) Arranged on one circle (D),
The track center line (Y) of the track groove (9) of the inner joint member is a mirror image of the track center line (X) of the track groove (7) paired with the outer joint member with reference to the plane (P). A fixed constant velocity universal joint characterized by being formed symmetrically. The offset of the center of curvature of the first track groove (7A), the track center line (X _A ) of _{the first track groove (7B), the arcuate portion of (X B) with respect to the projection center (O'), and the joint center (X B). The offset of the center of curvature of the arcuate portion of the track center line (X C} ) of the second track groove (7C) with respect to O) is provided toward the inner side of the outer joint member. The fixed constant velocity universal joint according to claim 1. _{The center of curvature of the track center lines (X A} ) and (X _B ) of the first track groove (7A) and (7B) and the track center line (X _C ) of the second track groove (7C) is described above. The fixed constant velocity universal joint according to claim 1 or 2, wherein the joint is offset in the radial direction with respect to the axis (NN) of the joint. The first track groove (7A), (7B) and the second track groove (7C) are different from the arcuate portions of the _{track center lines (X A} ), (X _B ), and (X _C). The invention according to any one of claims 1 to 3, wherein the high operating angle track groove portions (7Ab), (7Bb), and (7Cb) having a track centerline of the shape are provided on the opening side of the outer joint member. Fixed constant velocity universal joint. _{The track center lines (X Ab} ), (X _Bb ), and (X _Cb ) of the high operating angle track grooves (7Ab), (7Bb), and (7Cb) are the first track grooves (7A), (7B). It is characterized by having an arc shape that curves in the opposite direction to the arc-shaped portion of the track center line (X _A ), (X _B ) and the track center line (X _{C) of the second track groove (7C).} The fixed constant velocity universal joint according to claim 4. One of claims 1 to 5, wherein the cage has a pocket for accommodating two torque transmission balls incorporated in the first track grooves (7A) and (7B) of each pair. The fixed constant velocity universal joint described in item 1.

Images