JP4268572B2 - Constant velocity joint - Google Patents

Description

  The present invention relates to, for example, a constant velocity joint that connects one transmission shaft and the other transmission shaft in a driving force transmission unit of an automobile.

  Conventionally, in a driving force transmission unit of an automobile, a constant velocity joint that connects one transmission shaft and the other transmission shaft and transmits a rotational force to each axle is used.

  As a constant velocity joint according to this type of prior art, for example, Non-Patent Document 1 discloses an outer race arranged on a joint shaft (driving shaft and driven shaft) with an offset by an equal distance on both sides of the joint center. A Rzeppa type constant velocity joint having a ball groove center and an inner race ball groove center is disclosed.

  In this Rzeppa type constant velocity joint, the six balls held by the cage are bisected between the constant velocity surface or the joint shaft by the relative movement of the ball groove of the outer race and the ball groove of the inner race. By being positioned on the surface, the driving contact is always maintained on the constant velocity surface, and constant velocity performance is ensured.

  In this case, in Non-Patent Document 1, a generally used cross section of a ball groove (a cross section in a direction orthogonal to the joint axis) is formed in an elliptical arc shape, and the contact angle with the ball in the elliptical arc shaped ball groove is It is set to 30 degrees-45 degrees, and it is described that the contact angle employ | adopted most generally is 45 degrees.

  Patent Document 1 discloses a fixed type constant velocity universal joint composed of an outer joint member, an inner joint member, eight torque transmission balls and a cage, and a ball groove (track groove) of the outer joint member. And the center of the ball groove (track groove) of the inner joint member are offset to the opposite side by an equal distance in the axial direction, and the PCD gap in the ball track (the pitch circle diameter of the ball groove of the outer joint member and the inner joint member It is described that the difference between the pitch diameter of the ball grooves and the ball groove diameter is 5 to 50 μm.

  In Patent Document 1, by setting the PCD gap to 5 to 50 μm, the fixed type constant velocity universal joint having eight torque transmission balls can improve durability at high load and stabilize life variation. It can be realized.

  Furthermore, Patent Document 1 describes that the radial gap between the outer joint member and the cage is 20 to 100 μm, and the radial gap between the cage and the inner joint member is 20 to 100 μm. Has been.

  In Patent Document 1, the basic structure is different between a constant velocity universal joint having eight torque transmission balls and a constant velocity universal joint having six torque transmission balls. However, there is no disclosure or suggestion about setting values such as a PCD clearance regarding a constant velocity universal joint having six torque transmission balls.

  That is, in this type of constant velocity universal joint, how to set the PCD (pitch circle diameter) clearance with respect to the ball track formed by a pair of mutually opposing ball grooves of the outer joint member and the inner joint member? is important. This is because if the PCD gap is too small, it is difficult to assemble the ball when the ball is inserted into the ball track, and the restraining force on the ball is increased, which hinders the smooth rolling operation of the ball. Because. On the other hand, if the PCD gap is too large, there is a problem that a hitting sound is generated between the window portion of the cage and the ball, and joint vibration increases.

Japanese Patent Laid-Open No. 2002-323061 Charles E. Cooney, Jr., “UNIVERSAL JOINT AND DRIVESHAFT DESIGN MANUAL ADVANCES IN ENGINEERING SERIES NO.7” (USA), 2nd edition, THE SOCIETY OF AUTOMOTIVE ENGINEERS, INC. 1991 Year, p. 145-149

  The present invention has been made in view of the above points, and in a constant velocity joint having six balls, it is directly connected to the joint life by optimally setting various clearances and offset amounts of retainer holding windows. It is an object of the present invention to provide a constant velocity joint capable of improving durability by reducing the surface pressure between the outer side guide groove and the ball and between the inner side guide groove and the ball.

In order to achieve the above object, the present invention provides an outer body connected to one of two intersecting shafts, having a plurality of first guide grooves having an inner diameter surface and extending in the axial direction, and having one end opened. Members,
An inner ring connected to the other of the two shafts, extending in the axial direction and having the same number of second guide grooves as the first guide grooves;
Six balls that are arranged to roll between the first guide groove and the second guide groove and transmit torque,
A retainer having a holding window for storing the balls;
In constant velocity joints with
When the pitch circle diameter of the first guide groove is the outer PCD and the pitch circle diameter of the second guide groove of the inner ring is the inner PCD, the difference between the outer PCD and the inner PCD (outer PCD-inner PCD) The PCD clearance consisting of is set within a range of 0 to 100 μm.

  According to the present invention, when the PCD clearance is smaller than 0 μm, the assembly of the ball into the hole of the outer member is deteriorated, the smooth rolling operation of the ball is inhibited, and the durability is deteriorated. On the other hand, when the PCD clearance exceeds 100 μm, the contact ellipse between the ball and the first and second guide grooves protrudes from the shoulder at the end of the groove when the load is high, increasing the surface pressure and causing chipping of the shoulder. This is because the durability deteriorates.

  In this case, the difference between the inner spherical diameter of the outer member on the inner diameter surface of the outer member and the outer spherical diameter of the retainer on the outer surface of the retainer, and the inner spherical diameter of the retainer on the inner surface of the retainer and the outer outer spherical diameter of the inner ring. The spherical clearance [(outer inner sphere diameter) − (retainer outer sphere diameter)] + [(retainer inner sphere diameter) − (inner outer sphere diameter)] formed by adding the difference is in the range of 50 to 200 μm. It is good to set in.

  This is because if the spherical clearance is less than 50 μm, seizure occurs due to poor lubrication between the inner surface of the outer member and the outer surface of the retainer and between the outer surface of the inner ring and the inner surface of the retainer. On the other hand, if the spherical clearance exceeds 200 μm, a hitting sound is generated between the outer member and the inner ring and the retainer, which adversely affects the merchantability.

  Moreover, it is good to set the window width center of the holding | maintenance window formed in the said retainer to the position offset within the range of 20-100 micrometers along the axial direction of the said retainer from the spherical surface center of the outer surface and inner surface of the said retainer.

  If the amount of offset between the center of the retainer window width and the center of the spherical surface is smaller than 20 μm, it becomes difficult to secure constant velocity due to insufficient restraining force on the ball, and if it exceeds 100 μm, the restraining force becomes excessive and This is because the smooth rolling operation is hindered and the durability deteriorates.

  It is possible to prevent the occurrence of chipping or wear of the shoulder portion of the guide groove, and to reduce the surface pressure against the guide groove due to contact with the ball, thereby improving the durability.

  Preferred embodiments of the constant velocity joint according to the present invention will be described below and described in detail with reference to the accompanying drawings. In the present embodiment, the longitudinal section refers to a section along the axial direction of the first and second axes, and the transverse section refers to a section orthogonal to the axial direction.

  In FIG. 1, reference numeral 10 indicates a constant velocity joint according to an embodiment of the present invention. The constant velocity joint 10 is integrally connected to one end portion of the first shaft 12 and has an opening 14. It is basically composed of a cylindrical outer cup (outer member) 16 and an inner member 22 fixed to one end of the second shaft 18 and housed in the hole of the outer cup 16.

  As shown in FIGS. 1 and 3, the inner wall of the outer cup 16 has a spherical inner surface 24, and the inner surface 24 extends along the axial direction and around the axis. Six first guide grooves 26a to 26f are formed at intervals of 60 degrees.

  As shown in FIG. 2, the first guide groove 26 a (26 b to 26 f) formed in the outer cup 16 and having a longitudinal section along the axial direction having a curved shape has a point H as the center of curvature. In this case, the point H is formed along the axial direction of the outer cup 16 from the spherical center K of the inner diameter surface 24 (intersection where the imaginary plane (ball center plane) connecting the center point O of the ball 28 and the joint shaft 27 intersects). It is arranged at a position offset by a distance T1 on the opening 14 side.

  The cross sections of the first guide grooves 26a to 26f formed in the outer cup 16 are each a single circular arc having a center of curvature A on a vertical line L passing through the center O of the ball 28, as shown in FIG. The first guide grooves 26a to 26f are formed so as to be in contact with an outer surface of a ball 28 described later at one point B in the drawing.

  In practice, when a load is applied when transmitting rotational torque, the outer surface of the ball 28 and the first guide grooves 26a to 26f are not in point contact but in surface contact.

  The inner diameter surface 24 is continuously formed on both sides of the first guide grooves 26a to 26f in the transverse section, and the boundary portion between the first guide grooves 26a to 26f and the end portion and the inner diameter surface 24 is chamfered. A pair of first shoulders 30a, 30b is formed.

  The contact angle of the ball 28 with respect to the first guide grooves 26a to 26f of the outer cup 16 is set to zero degrees with respect to the vertical line L. Further, the ratio (M / N) of the groove radius M to the diameter N of the ball 28 in the cross section of the first guide grooves 26a to 26f may be set to 0.51 to 0.55 (see FIG. 4). ).

  The inner member 22 includes an inner ring 34 in which a plurality of second guide grooves 32 a to 32 f corresponding to the first guide grooves 26 a to 26 f are formed along the circumferential direction of the outer diameter surface 35, and an inner wall surface of the outer cup 16. The first guide grooves 26a to 26f formed on the inner ring 34 and the second guide grooves 32a to 32f formed on the outer diameter surface 35 (see FIG. 4) of the inner ring 34 are rotatably disposed and rotated. 6 balls 28 having a torque transmission function, and 6 holding windows 36 for holding the balls 28 are formed along the circumferential direction, and the retainer 38 is interposed between the outer cup 16 and the inner ring 34. Have

  The inner ring 34 is spline-fitted to the end of the second shaft 18 through a hole formed in the center, or via a ring-shaped locking member 40 attached to the annular groove of the second shaft 18. Are integrally fixed to the end of the second shaft 18. A plurality of second guide grooves 32 a to 32 f are formed on the outer diameter surface 35 of the inner ring 34 so as to correspond to the first guide grooves 26 a to 26 f of the outer cup 16 and are spaced apart at equal angles along the circumferential direction. The

  As shown in FIG. 2, the second guide grooves 32 a to 32 f formed in the inner ring 34 and having a longitudinal section along the axial direction formed in a curved shape have a point R as the center of curvature. In this case, the point R is a distance T2 along the axial direction from the spherical center K of the inner diameter surface 24 (intersection where the imaginary plane (ball center plane) connecting the center point O of the ball 28 and the joint shaft 27 is orthogonal). Arranged at the offset position.

  A point H that is the center of curvature of the first guide grooves 26a to 26f of the outer cup 16 and a point R that is the center of curvature of the second guide grooves 32a to 32f of the inner ring 34 are the spherical center K of the inner diameter surface 24 (ball center plane). And the joint shaft 27), which are respectively opposite to each other and offset at equal distances (T1 = T2) along the axial direction. The point H is located on the opening 14 side of the outer cup 16 with respect to the spherical surface center K of the inner diameter surface 24, and the point R is located on the back part 46 side of the outer cup 16. The radius of curvature of R is set so as to cross like a cross (see FIG. 2).

  In this case, the diameter of the ball 28 is N, and the offset amount (inner diameter surface 24) of the center of curvature (point H, point R) of the first guide grooves 26a to 26f of the outer cup 16 and the second guide grooves 32a to 32f of the inner ring 34 is set. The distance V along the axial direction from the spherical center K) is T, and the ratio of the diameter N to the offset amount T is V. The ratio V (= T / N) is 0.12 ≦ It is preferable that the diameter N and the offset amount T of the ball 28 are set so as to satisfy the relational expression of V ≦ 0.14.

  As shown in FIG. 4, the second guide grooves 32 a to 32 f have a cross section having an elliptical arc shape having a pair of centers C and D spaced apart from each other by a predetermined distance along the horizontal direction, and the second guide grooves 32 a. ˜32f are formed so as to contact the outer surface of the ball 28 at two points E and F in the drawing. In practice, when a load is applied when the rotational torque is transmitted, the outer surface of the ball 28 and the second guide grooves 32a to 32f are formed so as to be in surface contact rather than point contact.

  The outer diameter surface 35 is continuously formed on both sides of the second guide grooves 32a to 32f in the transverse section, and a chamfer is formed at a boundary portion between the second guide grooves 32a to 32f and the end portion and the outer diameter surface 35. A pair of second shoulder portions 42a, 42b is formed.

  The contact angle α of the ball 28 with respect to the second guide grooves 32a to 32f is set so as to be separated from the vertical line L by an equal angle α on the left and right. In this case, if the contact angle α of the ball 28 with respect to the second guide grooves 32a to 32f is set in the range of 13 degrees to 22 degrees, the durability is improved, and further, the ball 28 with respect to the second guide grooves 32a to 32f is improved. When the contact angle α is set in the range of 15 degrees to 20 degrees, extremely good durability can be obtained. Further, the ratios (P / N, Q / N) of the groove radii P and Q to the diameter N of the ball 28 in the cross section of the second guide grooves 32a to 32f are set to 0.51 to 0.55. It is good (see FIG. 4).

  The balls 28 are formed of, for example, steel balls and roll one by one along the circumferential direction between the first guide grooves 26 a to 26 f of the outer cup 16 and the second guide grooves 32 a to 32 f of the inner ring 34. Six are possible. The ball 28 transmits the rotational torque of the second shaft 18 to the first shaft 12 via the inner ring 34 and the outer cup 16, and along the first guide grooves 26a to 26f and the second guide grooves 32a to 32f. By rolling, relative displacement in the intersecting angular direction between the second shaft 18 (inner ring 30) and the first shaft 12 (outer cup 16) is enabled. The rotational torque is suitably transmitted from either direction between the first shaft 12 and the second shaft 18.

  As shown in FIGS. 5A and 5B, the pitch diameter of the first guide grooves 26a to 26f in the state where the six balls 28 are in point contact with the first guide grooves 26a to 26f of the outer cup 16 is referred to as an outer PCD. When the pitch diameter of the second guide grooves 32a to 32f in the state where the six balls 28 are in point contact with the second guide grooves 32a to 32f of the inner ring 34 is the inner PCD, the outer PCD and the inner The PCD clearance is set by the difference from the PCD (outer PCD-inner PCD).

  Further, as shown in FIGS. 6A to 6C, the difference between the outer inner sphere diameter on the inner diameter surface 24 of the outer cup 16 and the outer retainer sphere diameter on the outer diameter surface of the retainer 38, and the retainer inner sphere on the inner diameter surface of the retainer 38. The spherical clearance is set by adding the diameter and the difference between the inner outer sphere diameter on the outer diameter surface of the inner ring 34.

  In other words, spherical clearance = [(outer inner sphere diameter) − (retainer outer sphere diameter)] + [(retainer inner sphere diameter) − (inner outer sphere diameter)].

  Further, as shown in FIG. 7, the window width center of the holding window 36 of the retainer 38 (the axial direction of the retainer 38 is the width) and the spherical centers of the outer surface 38 a and the inner surface 38 b of the retainer 38 are It is arranged at a position offset by a predetermined distance along the axial direction.

  The constant velocity joint 10 according to the present embodiment is basically configured as described above. Next, the operation, action, and effect will be described.

  When the second shaft 18 rotates, the rotational torque is transmitted from the inner ring 34 to the outer cup 16 via each ball 28, and the first shaft 12 rotates in a predetermined direction while maintaining constant velocity with the second shaft 18. To do.

  At that time, when the crossing angle (operating angle) between the first shaft 12 and the second shaft 18 changes, the ball rolls between the first guide grooves 26a to 26f and the second guide grooves 32a to 32f. Under the action of 28, the retainer 38 tilts by a predetermined angle to allow the angular displacement.

  In this case, since the six balls 28 held by the holding window 36 of the retainer 38 are located on the uniform velocity surface or the bisected angle surface between the first shaft and the second shafts 12 and 18, the driving contact is made. The constant velocity is always maintained on the constant velocity surface. As described above, the angular displacement of the first shaft 12 and the second shaft 18 is preferably allowed while maintaining the constant velocity.

  In the present embodiment, the PCD clearance (see FIGS. 5A and 5B) formed by the difference between the outer PCD and the inner PCD (outer PCD−inner PCD) is set to 0 to 100 μm, and preferably set to 0 to 60 μm. Good. The reason why the PCD clearance is set to 0 to 100 μm is that when it becomes smaller than 0 μm, the assembling property of the ball 28 is deteriorated, the smooth rolling operation of the ball 28 is inhibited, and the durability is deteriorated. On the other hand, when the PCD clearance exceeds 100 μm, the contact ellipse between the ball 28 and the first and second guide grooves protrudes from the shoulder at the groove end when the load is high, increasing the surface pressure and causing the chipping of the shoulder. This is because the durability deteriorates. In this case, as shown in the experimental results of FIG. 8, extremely good durability can be obtained by setting the PCD setting range to 0 to 60 μm.

  In this embodiment, as shown in FIGS. 6A to 6C, [(outer inner sphere diameter) − (retainer outer sphere diameter)] + [((retainer inner sphere diameter) − (inner outer sphere diameter)] Is set to 50 to 200 μm, preferably 50 to 150 μm. This is because if the thickness is less than 50 μm, seizure occurs due to poor lubrication between the inner surface of the outer cup 16 and the outer surface 38a of the retainer 38 and between the outer surface of the inner ring and the inner surface 38b of the retainer 38. On the other hand, if the thickness exceeds 200 μm, a hitting sound is generated between the outer cup 16 and the inner ring 34 and the retainer 38, which adversely affects the merchantability. In this case, as shown in the experimental results of FIG. 9, by setting the spherical clearance setting range to 50 to 150 μm, extremely good durability can be obtained.

  Further, in the present embodiment, as shown in FIG. 7, the window width center of the holding window 36 of the retainer 38 (the axial direction of the retainer 38 is the width) is the spherical surfaces of the outer surface 38a and the inner surface 38b of the retainer 38. It is arranged at a position offset by 20 to 100 μm along the axial direction of the retainer 38 from the center. If the offset amount between the window width center of the retainer 38 and the center of the spherical surface is smaller than 20 μm, it is difficult to ensure the constant speed due to insufficient restraining force of the ball 28, and if it exceeds 100 μm, the restraining force becomes excessive and the ball 28 becomes excessive. This is because the smooth rolling operation is hindered and the durability deteriorates. In this case, as shown in the experimental results of FIG. 10, by setting the setting range of the offset amount between the window width center and the spherical surface center of the retainer 38 to 40 to 80 μm, extremely good durability can be obtained.

  As a result, in the present embodiment, in the constant velocity joint 10 including the six balls 28, even when the load is high, protrusion of the contact ellipse by the balls 28 can be suppressed and durability can be improved.

  Furthermore, in the present embodiment, the offset of the diameter N of the ball 28 and the center of curvature (point H, point R) of the first guide grooves 26a to 26f of the outer cup 16 and the second guide grooves 32a to 32f of the inner ring 34. The ratio V (= T / N) to the quantity (the distance along the axial direction from the spherical surface center K of the inner diameter surface 24) T is set so as to satisfy the relational expression of 0.12 ≦ V ≦ 0.14. The

  In this case, when the ratio V between the diameter N of the ball 28 and the offset amount T is less than 0.12, the wedge angle formed by the first guide grooves 26a to 26f and the second guide grooves 32a to 32f is minimal. Thus, the ball 28 is easily locked during non-rotating operation, and the workability during assembly deteriorates.

  On the other hand, if the ratio V between the diameter N of the ball 28 and the offset amount T exceeds 0.14, the depths of the first and second guide grooves 26a to 26f and 32a to 32f become shallow. It becomes difficult to prevent the first and second shoulder portions 30a, 30b, 42a, and 42b formed at the end portions of the second guide grooves 26a to 26f and 32a to 32f from getting on or chipping or wearing.

  As described above, the diameter N of the ball 28 and the offset amount T of the center of curvature (point H, point R) of the first and second guide grooves 26a to 26f and 32a to 32f are expressed by the relational expression (0.12 ≦ V ≦ 0.14), the first and second shoulders 30a, 30b, 42a, 42b formed at the ends of the first and second guide grooves 26a-26f, 32a-32f are set. The durability of the constant velocity joint 10 can be further improved by suitably preventing the occurrence of riding or chipping or wear.

  Further, the cross section of the first guide grooves 26a to 26f of the outer cup 16 is formed in an arc shape so as to make one point contact with the ball 28, and the cross section of the second guide grooves 32a to 32f of the inner ring 34 is elliptical arc shape. By forming the two-point contact with the ball 28, the contact pressure with respect to the first guide grooves 26a to 26f and the second guide grooves 32a to 32f due to the contact with the ball 28 is reduced as compared with the prior art. And durability can be improved.

  In this case, the ratio (M / N, P / N, Q) of the groove radius (M, P, Q) and the diameter N of the ball 28 in the cross section of the first guide grooves 26a-26f and the second guide grooves 32a-32f. / N) is set in the range of 0.51 to 0.55, and the contact angle of the first guide grooves 26a to 26f with the ball 28 is set to zero degrees with respect to the vertical line L, and the second guide groove By setting the contact angle α between 32a to 32f and the ball 28 in the range of 13 degrees to 22 degrees with the vertical line L as a reference, the surface pressure can be reduced and the durability can be further improved.

  Reason why the ratio of the groove radius (M, P, Q) to the diameter N of the ball 28 in the cross section of the first guide grooves 26a to 26f and the second guide grooves 32a to 32f is 0.51 to 0.55. Is less than 0.51, the groove radius (M, P, Q) and the diameter N of the ball 28 are too close to each other, so that it becomes a state close to a solid contact (full contact), and the ball 28 is poorly rolled. On the other hand, the durability deteriorates. On the other hand, when the value exceeds 0.55, the contact ellipse of the ball 28 becomes smaller, so that the contact surface pressure increases and the durability deteriorates.

  The PCD clearance, the spherical clearance, the window offset amount, the diameter N of the ball 28, and the offset amount of the first and second guide grooves 26a to 26f, 32a to 32f in the longitudinal centers (points H and R). The ratio V (T / N) with T, the contact angle α between the second guide grooves 32a to 32f and the ball 28, and the grooves in the cross section of the first guide grooves 26a to 26f and the second guide grooves 32a to 32f As for the ratio of the radius (M, P, Q) to the diameter of the ball 28, an optimum value is obtained as a result of repeating simulation and experiment many times.

  Furthermore, the reason why the contact angle α of the ball 28 with respect to the second guide grooves 32a to 32f is set in the range of 13 degrees to 22 degrees is that the load on the ball 28 increases when the contact angle α is less than 13 degrees. When the contact angle α exceeds 22 degrees, the contact position between the end portions (second shoulder portions 42a and 42b) of the second guide grooves 32a to 32f and the ball 28 is close to each other. This is because the contact ellipse protrudes and the surface pressure increases and the durability deteriorates.

It is a longitudinal cross-sectional view along the axial direction of the constant velocity joint which concerns on embodiment of this invention. FIG. 2 is a partially enlarged longitudinal sectional view of the constant velocity joint shown in FIG. 1. It is a partial cross section side view seen from the axial direction (arrow X direction) of the constant velocity joint shown in FIG. FIG. 2 is a partial enlarged cross-sectional view orthogonal to the axial direction of the constant velocity joint shown in FIG. 1. FIG. 5A is a longitudinal sectional view showing the outer PCD which is the pitch circle diameter of the first guide groove formed in the outer cup, and FIG. 5B is a diagram showing the inner PCD which is the pitch circle diameter of the second guide groove formed in the inner ring. It is a longitudinal cross-sectional view shown. FIG. 6A is a longitudinal sectional view showing the inner inner spherical diameter of the inner surface of the outer cup, FIG. 6B is a longitudinal sectional view showing the inner outer spherical diameter of the outer surface of the inner ring, and FIG. 6C is a retainer outer spherical diameter of the outer surface of the retainer. 2 is a longitudinal section showing the retainer inner spherical diameter of the inner surface of the retainer. It is a longitudinal cross-sectional view which shows the offset amount of the window width center of the holding window of a retainer, and the spherical surface center of the outer surface and inner surface of a retainer. It is explanatory drawing which shows the relationship between PCD clearance and durability. It is explanatory drawing which shows the relationship between spherical clearance and durability. It is explanatory drawing which shows the relationship between window offset and durability.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Constant velocity joint 12 ... 1st axis | shaft 16 ... Outer cup 18 ... 2nd axis | shaft 24 ... Inner diameter surface 26a-26f ... 1st guide groove 28 ... Ball | bowl 30a, 30b ... 1st shoulder part 32a-32f ... 2nd guide groove 34 ... Inner ring 36 ... Holding window 38 ... Retainers 42a, 42b ... Second shoulder

Claims (2)

An outer member connected to one of two intersecting shafts, having an inner diameter surface and having a plurality of first guide grooves each having an arcuate cross section extending in the axial direction and having one end opened;
An inner ring connected to the other of the two shafts, extending in the axial direction, having an elliptical cross section and having the same number of second guide grooves as the first guide grooves;
Six balls that are arranged to roll between the first guide groove and the second guide groove and transmit torque,
A retainer having a holding window for storing the balls;
In constant velocity joints with
When the pitch circle diameter of the first guide groove is the outer PCD and the pitch circle diameter of the second guide groove of the inner ring is the inner PCD, the difference between the outer PCD and the inner PCD (outer PCD-inner PCD) PCD clearance consisting of is set within the range of 0-100 μm,
The difference between the outer inner spherical diameter on the inner diameter surface of the outer member and the outer spherical diameter of the retainer on the outer surface of the retainer, and the difference between the inner spherical diameter of the retainer on the inner surface of the retainer and the inner outer spherical diameter on the outer surface of the inner ring. Spherical clearance [(outer inner sphere diameter) − (retainer outer sphere diameter)] + [(retainer inner sphere diameter) − (inner outer sphere diameter)] formed by adding is set within a range of 50 to 200 μm. The ball is in one point contact with the first guide groove having an arcuate cross section, the ball is in contact with the second guide groove having an elliptic arc shape, and the ball is further in contact with the second guide groove. constant velocity joint, characterized in that you set the contact angle α of the ball in the range of 13 degrees to 22 degrees. The constant velocity joint according to claim 1,
The window width center of the holding window formed on the retainer is set at a position offset within a range of 20 to 100 μm along the axial direction of the retainer from the spherical center of the outer surface and inner surface of the retainer. Constant velocity joint.

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