JP4880902B2 - 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. In recent years, the need for weight reduction of a constant velocity joint has increased, and further downsizing of the constant velocity joint has been demanded. In this case, the strength, durability, load capacity, etc. of the constant velocity joint are set according to the basic dimensions of each element constituting the constant velocity joint, and various characteristics such as the strength, durability, load capacity, etc. of the constant velocity joint are set. It is required to set dimensions corresponding to miniaturization while maintaining each of them.

  As a technical idea regarding the basic setting of this type of constant velocity joint, Patent Document 1 discloses a fixed type constant velocity universal joint including an outer joint member, an inner joint member, eight torque transmission balls, and a cage. The ratio Rw (= W / PCR) between the axial width (W) of the joint member and the length (PCR) of the line segment connecting the center of the guide groove of the inner joint member and the center of the torque transmitting ball is 0. .69 ≦ Rw ≦ 0.84 is disclosed.

Further, Patent Document 2, the outer race, inner race, in the fixed type constant velocity joint comprising six torque transmission balls and the cage, the diameter of the drive shaft is d, the torque transmitting balls diameter D _B and six set the pitch circle diameter of the torque transmitting balls when the D _P, which is the ratio of the diameter D _B of the torque transmission pawl to the diameter d of the drive shaft D _B / d to 0.65 to 0.72, the torque transmitting balls It is disclosed that D _P / D _B , which is a ratio of pitch circle diameter D _P to diameter D _B , is set to 3.4 to 3.8.

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

  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, the non-patent document 1 describes a common normal of a load side contact point between the outer race ball groove (guide groove) and the ball, and a load side contact point between the inner race ball groove (guide groove) and the ball. It is described that the wedge angle, which is the angle formed with the common normal line, is set to about 15 degrees to 17 degrees. This is to prevent the ball from being locked due to friction when the Rzeppa constant velocity joint performs a declination operation at a joint angle of around 0 degrees.

  Moreover, in the said nonpatent literature 1, the cross section (direction cross section orthogonal to a joint axis | shaft) of the generally used ball groove is formed in circular arc shape or elliptical arc shape, and the contact angle with the ball | bowl in an elliptical arc shape ball groove Is set to 30 degrees to 45 degrees, and it is described that the most commonly employed contact angle is 45 degrees.

  Further, Patent Document 3 and Patent Document 4 include an outer race, an inner race, eight balls, and a cage, and the center of the portion where the groove bottom of the outer race guide groove (track groove) is curved is the inner diameter. The center of the inner race guide groove (track groove) where the groove bottom is curved is opposite to the center of the outer diameter surface by an equal distance (F) in the axial direction. A fixed type constant velocity universal joint offset to the side is disclosed.

  In Patent Document 3, the ratio R1 (= F /) of the offset amount (F) and the length (PCR) of the line segment connecting the center of the outer race guide groove or the inner race guide groove and the center of the ball. (PCR) is set within a range of 0.069 ≦ R1 ≦ 0.121.

  Further, in Patent Document 4, the ratio R1 (=) of the offset amount (F) and the length (PCR) of the line segment connecting the center of the outer race guide groove or the center of the inner race guide groove and the center of the ball. F / PCR) is set in the range of 0.069 ≦ R1 ≦ 0.121, and the contact angle between each guide groove and the ball is set to 37 degrees or less.

  By the way, Patent Document 5 discloses a fixed type constant velocity universal joint constituted by 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 5, by setting the PCD gap to be 5 to 50 μm, in a fixed type constant velocity universal joint having eight torque transmission balls, durability is improved at high load and life variation is stabilized. It can be realized.

  Furthermore, Patent Document 5 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.

  By the way, the constant velocity joint according to this type of prior art is, for example, as shown in FIG. 24, an outer member (outer ring member) in which a plurality of curved guide grooves 1b are formed in the axial direction on a spherical inner surface 1a. 1 and an inner member (inner ring member) 2 in which a plurality of curved guide grooves 2b are formed in an axial direction on a spherical outer surface 2a, and a spline 2c is provided on an inner diameter surface. A ball rolling groove is integrally formed by the curved guide groove 1b of the outer member 1 and the curved guide groove 2b of the inner member 2, and a ball 3 for torque transmission is formed in the ball rolling groove. It is arranged. The ball 3 is held by a holding window 4 a formed on a substantially ring-shaped retainer 4.

  In this case, the joint strength when the angle is given to the outer member 1 and the inner member 2 is determined by the strength of the retainer 4. Therefore, in order to improve the joint strength when adding an angle, it is necessary to improve the strength of the retainer 4 itself.

  Here, in order to increase the strength of the retainer 4 itself, it can be dealt with by increasing the cross-sectional area of the retainer 4. As the method, the inner sphere diameter dimension of the retainer 4 is reduced, while the outer sphere diameter dimension is increased to increase the thickness of the retainer 4 (hereinafter referred to as the first method), the angle to the joint. The method of increasing the cross-sectional area on the side that receives the jumping force (hereinafter referred to as the second method) with respect to the jumping force of the ball 3 that is generated at the time of attaching, and the breakage of the column part 4b existing between the holding windows 4a Examples include a method for increasing the area (hereinafter referred to as a third method).

  However, in the first method and the second method described above, the retainer 4 becomes a heavy object or the width dimension increases, and the ball 3 bites into the curved guide groove 1b and the durability of the outer member 1 is increased. There are problems such as lowering. In addition, since the retainer 4 becomes wider, the retainer 4 may not be incorporated into the outer member 1.

  On the other hand, in the third method, when the pillar portion 4b is elongated and the opening area of the holding window 4a is reduced, the ball 3 is likely to come into contact with the pillar portion 4b, and the assembly failure of the ball 3 occurs. There's a problem. Furthermore, there is a problem that the inner member 2 cannot be easily assembled in the retainer 4 because the holding window 4a is too small.

  Therefore, for example, in Patent Document 6, a corner radius portion 4c is provided in the holding window 4a, and a ratio R / D between the radius of curvature R of the corner radius portion 4c and the diameter D of the ball 3 is 0.22 ≦ A constant velocity universal joint that is R / D is disclosed.

JP 2001-330051 A Japanese Patent Laid-Open No. 2003-97590 JP 2003-4062 A JP-A-9-317784 Japanese Patent Laid-Open No. 2002-323061 JP 2002-13544 A 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

  However, the technical idea disclosed in Patent Document 1 has a problem that the number of parts increases and the manufacturing cost increases, and when actually implemented, it is difficult in terms of production technology.

  Further, in the technical idea disclosed in Patent Document 2, it is a dimension setting for improving the strength of a cage (cage) that holds a torque transmission ball, and does not contribute to downsizing of a constant velocity joint. There is no problem.

  By the way, the ball track formed by the ball groove of the outer race and the ball groove of the inner race is formed in a wedge shape that gradually spreads in the axial direction from the back side of the opening of the outer race toward the opening. Therefore, since the ball grooves on the outer race side and the inner race side are at positions offset by an equal distance from the joint center, the depths of both ball grooves are not uniform in the axial direction.

  In the structure disclosed in Non-Patent Document 1, since the depth of the ball grooves of the outer race and the inner race becomes shallow, the contact ellipse of the ball is detached from the ball groove at a high operating angle or a high load. There is a risk of running over the shoulder (end) of the ball groove or chipping or wear of the shoulder of the ball groove, resulting in deterioration of durability. Further, when a high load is applied, it is assumed that the contact position between the ball groove and the ball is close to the end of the inner ring, and the contact ellipse protrudes to increase the contact surface pressure against the ball groove. The

  In Patent Document 3 and Patent Document 4, the offset amount (F) and the length (PCR) of the line segment connecting the center of the outer race guide groove or the center of the inner race guide groove and the center of the ball. Although it is disclosed that the ratio R1 (= F / PCR) is set to a predetermined value, in this case, the diameter of the ball is set to be small, or the constant velocity joint itself is further miniaturized to be the weakest part in strength. If the cage thickness is to be secured, the outer race and inner race guide groove depths are inevitably not sufficiently secured, and as described above, the shoulder portion of the guide groove may be chipped or worn. There is a problem.

  In Patent Document 5, the basic structure of a constant velocity universal joint having eight torque transmission balls is different from that of 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.

  Further, according to the technical idea disclosed in Patent Document 6, a ratio R between a radius of curvature R of a corner radius portion provided in a pocket (holding window) of a retainer (retainer) and a diameter D of a torque transmitting ball. Although the purpose is to improve durability and strength by setting / D, there is a problem that the strength of the cage cannot be sufficiently improved only by setting the above conditions.

  The present invention has been made in consideration of the above-mentioned various problems, and provides a constant velocity joint capable of reducing the surface pressure against the guide groove due to contact with the ball and improving the durability. Objective.

  Another object of the present invention is to provide a constant velocity joint capable of improving the durability by preventing the occurrence of chipping or wear of the shoulder portion of the guide groove.

  Another object of the present invention is to provide an outer side guide groove and a ball that are directly connected to the joint life by optimally setting various clearances and offset amounts of the retainer holding window in a constant velocity joint having six balls. And a constant velocity joint capable of reducing the surface pressure between the inner side guide groove and the ball and improving the durability.

  Still another object of the present invention is to provide a constant velocity joint capable of setting various dimensions corresponding to downsizing while maintaining various characteristics such as strength, durability, and load capacity. is there.

  Still another object of the present invention is to provide a constant velocity joint capable of ensuring the strength of the retainer and improving the assembly workability.

In order to achieve the above object, the present invention provides an outer member 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 portion opened. A member,
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
The first guide groove formed in the outer member is formed so that a cross section perpendicular to the axial direction has a single arc shape, and is in contact with the ball at one point,
The second guide groove formed in the inner ring has an elliptical arc cross section perpendicular to the axial direction, and is formed so as to contact the ball at two points.
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.

Further, the present invention is an outer member that is coupled to one of two intersecting shafts, has an inner surface formed of a spherical surface, has a plurality of first guide grooves extending in the axial direction, and has an opening at one end.
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
The first guide groove formed in the outer member is formed so that a cross section perpendicular to the axial direction has a single arc shape, and is in contact with the ball at one point,
The second guide groove formed in the inner ring has an elliptical arc cross section perpendicular to the axial direction, and is formed so as to contact the ball at two points.
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 center of curvature (H) of the first guide groove formed in the outer member and having a curved longitudinal section along the axial direction, and the longitudinal section formed in the inner ring and curved in the axial direction are curved. 2 The center of curvature (R) of the guide groove is disposed at a position offset from the spherical center (K) by an equal distance (T) on the opposite side along the axial direction.
The diameter (N) of the ball and the offset amount (T) of the first guide groove and the second guide groove is a relational expression of 0.12 ≦ V ≦ 0.14, where V is the ratio (T / N). It is set so that it may be satisfied.

  According to the present invention, the cross section of the first guide groove of the outer member is formed in an arc shape to make one-point contact with the ball, and the cross section of the second guide groove of the inner ring is formed in an elliptic arc shape. By making two-point contact with the ball, the surface pressure against the first and second guide grooves due to contact with the ball can be reduced and durability can be improved as compared with the prior art.

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

  More preferably, the contact angle (α) between the second guide groove and the ball is set to a range of 15 degrees to 20 degrees with respect to the vertical line (L).

  Further, according to the present invention, when the PCD clearance is smaller than 0 μm, the assembling property of the ball with respect to 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.

  Further, according to the present invention, the ratio V (T / N) between the diameter (N) of the ball and the offset amount T of the center of curvature (H, R) of the first and second guide grooves is represented by the relational expression (0. 12 ≦ V ≦ 0.14) is set so that the shoulders formed at the end portions of the first and second guide grooves or the occurrence of chipping or wear can be suitably prevented. The durability of the constant velocity joint can be improved.

  In this case, if the ratio V (T / N) of the ball diameter (N) to the offset amount (T) is less than 0.12, the wedge angle formed by the first guide groove and the second guide groove is It becomes a minimum state, and the locked state of the ball at the time of non-rotating operation is likely to occur, and workability at the time of assembling deteriorates. On the other hand, if the ratio V (T / N) of the ball diameter (N) to the offset amount (T) exceeds 0.14, the depth of the first and second guide grooves becomes shallow. In addition, it is difficult to prevent the shoulder portion formed at the end portion of the second guide groove from climbing or chipping or wearing.

  Furthermore, according to the present invention, the outer PCD and the inner PCD have the same size (Dp) of the outer inner PCD, and an inner diameter inner diameter portion formed on the inner wall surface of the hole of the inner ring. The ratio (Dp / D) to the diameter (D) is preferably set within a range of 1.9 ≦ (Dp / D) ≦ 2.2. If the dimensional ratio (Dp / D) between the outer inner PCD (Dp) and the diameter (D) of the inner diameter of the inner serration is less than 1.9, the inner ring is too thin and the strength decreases. On the other hand, if the dimensional ratio (Dp / D) exceeds 2.2, the constant velocity joint cannot be reduced in size.

  Further, the ratio (Db / Dp) of the diameter (Db) of the ball to the dimension (Dp) of the outer inner PCD where the outer PCD and the inner PCD are the same is 0.2 ≦ (Db / Dp) It is preferable to set within the range of ≦ 0.5. In this case, if the dimensional ratio (Db / Dp) is less than 0.2, there is a problem that the ball diameter becomes too small and the durability is lowered, while the dimensional ratio (Db / Dp) is 0. If it exceeds 5, the ball becomes large, the thickness of the outer member becomes relatively thin, and the strength decreases.

  Further, the ratio (Do / Dp) between the outer diameter (Do) of the outer member and the dimension (Dp) of the outer inner PCD in which the outer PCD and the inner PCD are the same is 1.4 ≦ (Do / Dp) is preferably set within the range of 1.8. In this case, if the dimensional ratio (Do / Dp) is less than 1.4, there is a problem that the thickness of the outer member is reduced and the strength is lowered, while the dimensional ratio (Do / Dp) is 1. If it exceeds 8, the outer diameter of the outer member will become large, and miniaturization cannot be achieved.

  The ratio (Dp) of the dimension (Dp) of the outer inner PCD in which the outer PCD and the inner PCD are the same, and the diameter (D) of the inner diameter inner diameter portion formed on the inner wall surface of the hole of the inner ring / D) is set within the range of 1.9 ≦ (Dp / D) ≦ 2.2, and the ratio (Db) between the diameter (Db) of the ball and the dimension (Dp) of the outer inner PCD / Dp) is set within the range of 0.2 ≦ (Db / Dp) ≦ 0.5, and the ratio between the outer diameter (Do) of the outer member and the dimension (Dp) of the outer inner PCD It is preferable that (Do / Dp) is set within a range of 1.4 ≦ (Do / Dp) ≦ 1.8.

  Furthermore, according to the present invention, the holding window has an opening length (WL) in the circumferential direction of the retainer, and a ratio (WL) between the opening length (WL) and the ball diameter (N). / N) is preferably set within the range of 1.30 ≦ WL / N ≦ 1.42. The holding window has a corner with a radius of curvature R, and the ratio (R / N) of the radius of curvature (R) to the diameter (N) of the ball is 0.23 ≦ R / N ≦ 0.45. It is preferable to set within the range.

  By setting the relationship of 0.23 ≦ R / N, it is possible to reduce the maximum main stress load of the column portion between the holding windows and improve the strength of the retainer. On the other hand, by setting the relationship of R / N ≦ 0.45, it is possible to effectively prevent the corner portion of the holding window from becoming too large and causing a defective integration of the ball and the inner ring.

  The first guide groove and the second guide groove may be formed so as to have a curved shape portion and a linear shape portion (S1, S2) along the longitudinal direction. The first guide groove and the second guide groove are preferably formed so as to have only a curved portion along the longitudinal direction.

  The cross section of the first guide groove of the outer member is formed in an arc shape to make one point contact with the ball, and the cross section of the second guide groove of the inner ring is formed in an elliptic arc shape to form two points with respect to the ball By making contact, the surface pressure against the guide groove due to contact with the ball can be reduced and durability can be improved.

  Further, the first and second guide grooves formed on the outer member and the inner ring respectively prevent the occurrence of chipping or wear of the shoulder portions, and reduce the surface pressure against the guide grooves due to contact with the ball, thereby improving durability. Can be improved.

  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 FIG. 1, reference numeral 10 indicates a constant velocity joint according to an embodiment of the present invention. In the following description, the vertical cross section refers to a cross section along the axial direction of the first shaft 12 and the second shaft 18, and the horizontal cross section refers to a cross section orthogonal to the axial direction.

  The constant velocity joint 10 is fixedly connected to one end portion of the first shaft 12 and is integrally connected to one end portion of the first shaft 12 and has a bottomed cylindrical outer cup (outer member) 16 having an opening 14 and one end portion of the second shaft 18. The inner member 22 is basically composed of a hole portion 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 is formed on the 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 peripheral surface, and the inner wall surface of the outer cup 16. Rotation between the first guide grooves 26a to 26f formed and the second guide grooves 32a to 32f formed on the outer diameter surface 35 (see FIG. 4) of the inner ring 34 is possible. A plurality of (in this embodiment, six) balls 28 having a function and a plurality of holding windows 36 for holding the balls 28 are formed along the circumferential direction, and are interposed between the outer cup 16 and the inner ring 34. And a retainer 38 mounted thereon.

  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 along the axial direction from the spherical center K of the inner diameter surface 24 (intersection where the imaginary plane connecting the center point O of the ball 28 (the center plane of the ball 28) and the joint shaft 27 are orthogonal). Arranged at a position offset by T2.

  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 surface 24 (the ball 28 (The intersection of the center plane and the joint shaft 27) are located 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, the point R is located on the back 46 side of the outer cup 16, and the radius of curvature of the point H and the radius of curvature of the point R are as follows. Are 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 (spherical center K) 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) is T, and the ratio of the diameter N to the offset amount T is V. The ratio V (= T / N) is 0.12 ≦ V ≦ 0. It is preferable that the diameter N and the offset amount T of the ball 28 are set so as to satisfy the 14 relational expressions.

  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 a range of 13 degrees to 22 degrees as shown in FIG. 7, the durability is improved. When the contact angle α of the ball 28 with respect to the grooves 32a to 32f 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. It is possible to arrange. 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 34) 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. 8A and 8B, the pitch diameter of the first guide grooves 26a to 26f when the six balls 28 are in point contact with the first guide grooves 26a to 26f of the outer cup 16 is defined 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. 9A to 9C, the difference between the inner spherical diameter of the outer diameter surface 24 of the outer cup 16 and the outer spherical diameter of the retainer 38 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)].

  Furthermore, as shown in FIG. 10, 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 38a and the inner surface 38b 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 bisector angle plane between the first shaft 12 and the second shaft 18, the driving contact is always made. It is maintained on the constant velocity surface, and constant velocity is ensured. 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 diameter N of the ball 28 and the offset amount (spherical surface) 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. A ratio V (= T / N) with respect to the separation distance T along the axial direction from the center K is set so as to satisfy the relational expression of 0.12 ≦ V ≦ 0.14 (see FIG. 2).

  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.

  FIG. 5 shows a partial enlargement in a longitudinal section of the constant velocity joint 10 according to the present embodiment. The diameter N of the ball 28 and the centers of curvature of the first and second guide grooves 26a to 26f and 32a to 32f (point H, By satisfying the relational expression regarding the relationship between the point R) and the offset amount T, the offset amount T1 is set small. On the other hand, FIG. 6 shows a partial enlargement in the longitudinal section of the constant velocity joint 100 according to the comparative example, and the offset amount T2 is set to be larger than that in the present embodiment (T1 <T2).

  In this case, when the depths of the first guide grooves 26a to 26f of the outer cup 16 are compared with each other at a portion inclined by about 15 degrees with respect to the straight line S orthogonal to the joint shaft 27 and passing through the center of the ball 28, the present embodiment Since the depth DP1 of the first guide grooves 26a to 26f can be formed larger than the depth DP2 of the first guide groove of the comparative example (DP1> DP2), the end portions of the first guide grooves 26a to 26f The first and second shoulder portions 30a, 30b, 42a, and 42b formed on the first and second shoulder portions 30a, 42b and 42b can be suitably prevented from getting on or chipping or wearing.

  Further, in the present embodiment, 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 second guide grooves 32a to 32f of the inner ring 34 are formed. Are formed in an elliptical arc shape so as to be in two-point contact with the ball 28, so that the first guide grooves 26a to 26f and the second guide grooves 32a to 32a due to contact with the ball 28 are compared with the prior art. The surface pressure with respect to 32f can be reduced and durability can be improved.

  In this case, in the present embodiment, the ratio (M / N) 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 to 26f and the second guide grooves 32a to 32f. , P / N, Q / N) are set in the range of 0.51 to 0.55, respectively, 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. Furthermore, by setting the contact angle α between the second guide grooves 32a to 32f and the ball 28 within a range of 13 degrees to 22 degrees with respect to the vertical line L, the surface pressure is reduced and the durability is further improved. be able to.

  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.

  A ratio V (T / N) between 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 in the longitudinal section, The contact angle α between the second guide grooves 32a to 32f and the ball 28, and the groove radius (M, P, Q) and the ball 28 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 diameters, the optimum values were obtained as a result of repeating the simulation and the 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.

  Furthermore, in this embodiment, the PCD clearance (see FIGS. 8A and 8B) formed by the difference between the outer PCD and the inner PCD (outer PCD−inner PCD) is 0 to 100 μm, preferably 0 to 60 μm. It is good to set to. 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 first and second shoulder portions 30a, 30b, and 42a whose contact ellipses between the ball 28 and the first and second guide grooves 26a to 26f and 32a to 32f are groove ends when the load is high. 42b, the surface pressure increases, and the first and second shoulder portions 30a, 30b, 42a, 42b are chipped, resulting in deterioration of durability. In this case, as shown in the experimental results of FIG. 11, extremely good durability can be obtained by setting the PCD setting range to 0 to 60 μm.

  Furthermore, in this embodiment, as shown in FIGS. 9A to 9C, [(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 34 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. 12, extremely good durability can be obtained by setting the spherical clearance to a range of 50 to 150 μm.

  Furthermore, in the present embodiment, as shown in FIG. 10, 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 surface 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 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 too large. This is because the smooth rolling operation is hindered and the durability deteriorates. In this case, as shown in the experimental results of FIG. 13, 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.

  Next, setting of various dimensions of the constant velocity joint 10 will be described in detail.

  In this case, the outer PCD and the inner PCD shown in FIGS. 8A and 8B are equal (outer PCD = inner PCD), and the difference between the outer PCD and the inner PCD is set to zero. In the following description, both the outer PCD and the inner PCD are collectively referred to as “outer inner PCD”.

  A diameter (D) of the inner diameter inner diameter portion 39 is arbitrarily set, and a dimension of the outer inner PCD which is the minimum wall thickness of the inner ring 34 is set based on the diameter (D) of the inner diameter inner diameter portion 39 (FIG. 14 and FIG. 15).

  The diameter (D) of the inner diameter inner diameter portion 39 passes through the center of the hole of the inner ring 34, and the bottom of the valley portion of one inner diameter inner diameter portion 39 and the valley portion of the other inner diameter inner diameter portion 39. This means the dimension (maximum diameter) between the bottom part (see FIG. 15). A predetermined bond strength is ensured by the minimum thickness of the inner ring 34. As shown in FIG. 16, the value of the outer inner PCD is obtained from a characteristic straight line L related to the relationship between the diameter of the inner inner diameter portion 39 and the outer inner PCD.

  In this case, if the diameter of the inner inner diameter portion 39 is D and the outer inner PCD is Dp (see FIG. 14 and FIG. 15), the outer inner PCD (Dp) and the inner diameter inner diameter portion 39 (D). The dimensional ratio (Dp / D) is preferably set within the range of 1.9 ≦ (Dp / D) ≦ 2.2.

  If the dimensional ratio (Dp / D) is less than 1.9, there is a problem that the inner ring 34 becomes too thin and the strength is lowered. On the other hand, the dimensional ratio (Dp / D) is 2.2. This is because the constant velocity joint 10 cannot be reduced in size.

  Further, as shown in FIG. 17, the outer diameter of the outer cup 16 is set based on a characteristic straight line M relating to the relationship between the outer diameter of the cup portion of the outer cup 16 and the outer inner PCD. 14 and 15, when the outer diameter of the outer cup 16 is Do, the dimensional ratio (Do / Dp) between the outer diameter (Do) of the outer cup 16 and the outer inner PCD (Dp) is as follows. 1.4 ≦ (Do / Dp) ≦ 1.8 is preferably set.

  If the dimensional ratio (Do / Dp) is less than 1.4, there is a problem that the thickness of the outer cup 16 is reduced and the strength is lowered, while the dimensional ratio (Do / Dp) exceeds 1.8. This is because the outer diameter of the outer cup 16 becomes large and the miniaturization cannot be achieved.

  Further, as shown in FIG. 18, the ring width of the inner ring 34 is based on a characteristic straight line N relating to the relationship between the ring width of the inner ring 34 along the axial direction of the second shaft 18 and the outer inner PCD. Set. In this case, when the ring width of the inner ring 34 is W, the dimensional ratio (W / Dp) between the ring width (W) of the inner ring 34 and the outer inner PCD (Dp) is 0.38 ≦ (W / Dp ) ≦ 0.42 is preferable.

  Furthermore, as shown in FIG. 19, the diameter of the ball 28 is set based on a characteristic straight line Q relating to the relationship between the diameter of the ball 28 and the outer inner PCD. In this case, as shown in FIGS. 14 and 15, when the diameter of the ball 28 is Db, the dimensional ratio (Db / Dp) of the diameter (Db) of the ball 28 and the outer inner PCD (Dp) is 0.2. It is preferable to set within the range of ≦ (Db / Dp) ≦ 0.5.

  If the dimensional ratio (Db / Dp) is less than 0.2, there is a problem that the diameter of the ball 28 becomes too small and the durability is lowered, while the dimensional ratio (Db / Dp) is 0.5. If it exceeds, the ball 28 becomes large, the thickness of the outer cup 16 becomes relatively thin, and the strength is lowered. The inner sphere diameter and outer sphere diameter of the retainer 38 that holds the ball 28 are arbitrarily set according to the layout.

  In this way, by setting each dimension, various dimensions of the constant velocity joint 10 corresponding to downsizing can be set while maintaining various characteristics such as strength, durability, and load capacity.

  Next, the relationship between the opening length (WL) and the diameter (N) of the ball 28 in the circumferential direction of the holding window 36 formed in the retainer 38 will be described in detail with reference to FIGS.

  As shown in FIG. 20, the inner surface 24 of the outer cup 16 has six first guide grooves extending along the axial direction (arrow X direction) and spaced about 60 degrees around the axis. 26a-26f are formed, and each said 1st guide groove 26a-26f has the linear shape part S1 provided integrally from a curved shape part along a longitudinal direction (arrow X direction).

  On the outer diameter surface 35 of the inner ring 34, the same number of second guide grooves 32a to 32f as the first guide grooves 26a to 26f extending in the axial direction are formed. Each of the second guide grooves 32a to 32f has a linear shape portion S2 provided integrally from the curved shape portion along the longitudinal direction (arrow X direction), and each of the linear shape portions S1 and S2 is in the arrow X direction. Are provided in opposite directions to each other.

  As shown in FIGS. 21 and 22, the retainer 38 has a substantially ring shape, and six holding windows 36 each holding the ball 28 are formed at equiangular intervals along the circumferential direction.

  As shown in FIG. 22, each holding window 36 has an opening length (WL) in the circumferential direction of the retainer 38, and a ratio WL / N between the opening length (WL) and the diameter (N) of the ball 28. Is set to a relationship of 1.30 ≦ WL / N ≦ 1.42. Each holding window 36 has a corner 36a with a radius of curvature R, and the ratio R / N between the radius of curvature R and the diameter (N) of the ball 28 is 0.23 ≦ R / N ≦ 0.45. Set to

  In the constant velocity joint 10, as shown in FIG. 22, in each holding window 36 of the retainer 38, the circumferential opening length (WL) of the retainer 38 and the diameter (N) of the ball 28 are WL / N ≦ The relationship of 1.42 is set. For this reason, the retainer 38 can effectively maintain the circumferential length of the column portion 136 between the holding windows 36, and it is not necessary to set the thickness of the retainer 38 to be large, and the cross-sectional area of the column portion 136 is not necessary. It becomes possible to improve.

  Therefore, the retainer 38 can improve the strength of the retainer 38 satisfactorily, for example, without setting the inner sphere diameter size to be small and the outer sphere diameter size being set to be large or the axial width dimension to be long. The effect that it can be made is acquired.

  Moreover, in the constant velocity joint 10, the opening length (WL) of the holding window 36 and the diameter (N) of the ball 28 are set to satisfy a relationship of 1.30 ≦ WL / N. Thereby, it becomes possible to increase the opening area of each holding window 36, and it is possible to effectively prevent a defective assembly of the ball 28, a defective assembly of the inner ring 34, and the like. For this reason, the constant velocity joint 10 has an advantage that the assembly workability can be easily improved with a simple configuration.

  Further, the radius of curvature R of the corner portion 36a of the holding window 36 and the diameter (N) of the ball 28 are set to have a relationship of 0.23 ≦ R / N, so that the column portion 136 between the holding windows 36 The maximum principal stress load can be reduced and the strength of the retainer 38 can be improved.

  On the other hand, by setting the relationship of R / N ≦ 0.45, it is possible to effectively prevent the corner portion 36a of the holding window 36 from becoming too large and causing the defective integration of the ball 28 and the inner ring 34. Is possible.

  Furthermore, in the constant velocity joint 10, the first guide grooves 26a to 26f have a linear shape portion S1 along the longitudinal direction, and the second guide grooves 32a to 32f have a linear shape portion S2 along the longitudinal direction. ing. Therefore, the maximum operating angle of the constant velocity joint 10 can be effectively set large.

  As shown in FIG. 23, the first guide grooves 26a to 26f and the second guide grooves 32a to 32f may be formed so as to have only curved portions along the longitudinal direction.

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. It is a partial expanded longitudinal cross-sectional view which shows the depth of the 1st guide groove of the constant velocity joint in this Embodiment. It is a partial expanded longitudinal cross-sectional view which shows the depth of the 1st guide groove of the constant velocity joint which concerns on a comparative example. It is explanatory drawing which shows the relationship between the contact angle of a 2nd guide groove and a ball | bowl, and durability. FIG. 8A is a longitudinal sectional view showing the outer PCD that is the pitch circle diameter of the first guide groove formed in the outer cup, and FIG. 8B is the inner PCD that is the pitch circle diameter of the second guide groove formed in the inner ring. It is a longitudinal cross-sectional view shown. FIG. 9A is a longitudinal sectional view showing the inner inner spherical diameter of the inner surface of the outer cup, FIG. 9B is a longitudinal sectional view showing the inner outer spherical diameter of the outer surface of the inner ring, and FIG. 9C 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. It is a partial cross section side view seen from the axial direction (arrow X direction) of the constant velocity joint shown in FIG. It is a partial expanded sectional view of the constant velocity joint which shows a shaft serration part diameter (D), outer inner PCD (Dp), outer cup outer diameter (Do), ball diameter (Db), etc. It is a characteristic view which shows the characteristic straight line L concerning the relationship between the diameter of an inner serration inner diameter part, and outer inner PCD. It is a characteristic view which shows the characteristic straight line M which concerns on the relationship between the outer inner PCD and the outer diameter of an outer cup. It is a characteristic view which shows the characteristic straight line N concerning the relationship between the outer inner PCD and the inner width of the inner ring. It is a characteristic view which shows the characteristic straight line Q which concerns on the relationship between outer inner PCD and a ball diameter. It is a longitudinal cross-sectional view along the axial direction of the constant velocity joint used for description of the relationship between the holding window formed in the retainer and the ball. It is a disassembled perspective view of the retainer and ball | bowl which comprise the constant velocity joint shown in FIG. It is the side view seen from the circumferential direction explaining each dimension of the retainer and the ball | bowl shown by FIG. It is a longitudinal cross-sectional view along the axial direction of the constant velocity joint provided for description of the 1st guide groove and 2nd guide groove which have only a curved shape part along a longitudinal direction. It is a disassembled perspective view of the constant velocity joint which concerns on a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Constant velocity joint 12, 18 ... Shaft 16 ... Outer cup 24 ... Inner diameter surface 26a-26f ... 1st guide groove 28 ... Ball 30a, 30b, 42a, 42b ... Shoulder part 32a-32f ... 2nd guide groove 34 ... Inner ring 35 ... Outer surface 36 ... Holding window 36a ... Corner 38 ... Retainer 136 ... Column

Claims (2)

An outer member connected to one of two intersecting shafts, having an inner diameter surface and extending in the axial direction, and having a plurality of first guide grooves open at one end;
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
The first guide groove formed in the outer member is formed so that a cross section perpendicular to the axial direction has a single arc shape, and is in contact with the ball at one point,
The second guide groove formed in the inner ring has an elliptical arc cross section perpendicular to the axial direction, and is formed so as to contact the ball at two points.
The ball is in contact with the first guide groove at one point regardless of whether there is a load, and at the same time maintains the state of contacting the second guide groove at two points;
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) A constant velocity joint characterized in that the PCD clearance is set within a range of 0 to 100 μm. An outer member connected to one of two intersecting shafts, having an inner surface formed of a spherical surface and having a plurality of first guide grooves extending in the axial direction and having one end portion open;
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
The first guide groove formed in the outer member is formed so that a cross section perpendicular to the axial direction has a single arc shape, and is in contact with the ball at one point,
The second guide groove formed in the inner ring has an elliptical arc cross section perpendicular to the axial direction, and is formed so as to contact the ball at two points.
The ball is in contact with the first guide groove at one point regardless of whether there is a load, and at the same time maintains the state of contacting the second guide groove at two points;
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 center of curvature (H) of the first guide groove formed in the outer member and having a curved longitudinal section along the axial direction, and the longitudinal section formed in the inner ring and curved in the axial direction are curved. 2 The center of curvature (R) of the guide groove is arranged at a position offset by an equal distance (T) on the opposite side along the axial direction from the spherical center (K) of the inner diameter surface of the outer member,
The diameter (N) of the ball and the offset amount (T) of the first guide groove and the second guide groove is a relational expression of 0.12 ≦ V ≦ 0.14, where V is the ratio (T / N). A constant velocity joint that is set to satisfy

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