JP2008069889A - Fixed type constant velocity universal joint - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fixed type constant velocity universal joint, in which the size is reduced, a load capacity with an operating angle is not susceptible to reduction even if the size is reduced, and high-angle strength and durability are improved by alleviating ride of balls on a track at a high angle. <P>SOLUTION: In the fixed type constant velocity universal joint, a cage 28 has four pockets 29 of a pair of long pockets 30 between which a large circumferential space exists and a pair of short pockets 31 between which a small circumferential space exists. The pair of long pockets 30 are shifted 180° to each other along the circumferential direction, and the pair of short pockets 31 are shifted at 180° to each other along the circumferential direction. The long pockets 30 and the short pockets 31 are alternately arranged along the circumferential direction. The long pockets 30 store two balls 27, and the short pockets 31 store one ball. A circumferentially continuous circular arc part 36 is formed in an end part on the depth side of the joint of an outer spherical surface 24 of an inner member. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

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

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

  14 and 15, the UJ type fixed type constant velocity universal joint has an outer ring as an outer member in which a plurality of track grooves 2 are formed along the axial direction at equal intervals in the circumferential direction on the inner spherical surface 1. 3, an inner ring 6 as an inner member in which a plurality of track grooves 5 paired with the track grooves 2 of the outer ring 3 are formed on the outer spherical surface 4 along the axial direction at equal intervals in the circumferential direction, and a track of the outer ring 3 A plurality of balls 7 that are interposed between the groove 2 and the track groove 5 of the inner ring 6 and transmit torque, and are interposed between the inner spherical surface 1 of the outer ring 3 and the outer spherical surface 4 of the inner ring 6 to hold the balls 7. And a cage 8 to be operated. The cage 8 is provided with a plurality of pockets 9 for accommodating the balls 7 along the circumferential direction.

  The track groove 2 of the outer ring 3 includes a back-side track groove 2a in which the track groove bottom is an arc portion and an opening-side track groove 2b in which the track groove bottom is a straight portion parallel to the outer ring axis. The back side track groove 2a has its center of curvature O1 shifted from the joint center O in the axial direction toward the opening side of the outer ring 3. The track groove 5 of the inner ring 6 includes a back side track groove 5a in which the track groove bottom is a straight portion parallel to the inner ring axis, and an opening side track groove 5b in which the track groove bottom is an arc portion. The center of curvature O2 of the opening side track groove 5b is provided at an equal distance k away from the joint center O in the axial direction on the back side opposite to the center of curvature O1 of the back side track groove 2a of the outer ring 3.

  Further, the cage outer spherical surface 8a shifts its radius of curvature O3 from the joint center O in the axial direction toward the opening side of the cage 8, and the cage inner spherical surface 8b has its curvature center O4 moved from the joint center O in the axial direction to the cage outer spherical surface 8a. Is provided on the far side opposite to the center of curvature O3 by an equal distance k1. In this type of conventional constant velocity universal joint, the track offset amount of the inner and outer rings is increased, and the offset amount of the cage is decreased. Further, as shown in FIG. 15, the pitch angle between two adjacent balls 7 is 60 degrees. That is, six balls 7 are arranged at a pitch of 60 degrees along the circumferential direction.

  By the way, in recent years, it has been demanded that the fixed type constant velocity universal joint can be reduced in size and the torque load capacity can be increased. As a method for reducing the size of the fixed type constant velocity universal joint having six balls and increasing the torque load capacity, it is conceivable to place the largest possible ball on the smallest possible PCD. However, when a large ball is used, the column (window column) between the pockets of the cage becomes thin, and the rigidity of the cage decreases. In particular, for a torsional torque load at a high angle, the cage is easily damaged, which causes a decrease in strength of the constant velocity universal joint.

  In particular, as shown in FIG. 14, when the track offset amount of the inner and outer rings is large and the offset amount of the cage is small, the depth of the track groove on the inner side of the outer ring becomes shallow, and the torque load capacity at high angles becomes small. That is, the ball tends to ride on the track edge with respect to a torque load at a high angle, and an excessive stress is generated at the edge portion. For this reason, damage due to chipping of the edge portion or a locking phenomenon with the cage due to plastic deformation occurs. These damages and lock phenomena deteriorate the operability, reduce the durability life, and cause the cage to break. In addition, the inner ring has a shallower track depth on the back side, and has the same drawbacks as the outer ring. For this reason, improvement of joint strength and durability in a high angle region is a conventional problem.

  Therefore, conventionally, by increasing the circumferential length dimension of the pillar portion existing between the pockets adjacent in the circumferential direction to ensure the durability of the cage, the durability of the entire constant velocity universal joint is improved. There is one designed to improve (Patent Document 1). That is, the one described in Patent Document 1 stores a plurality of balls in one pocket, thereby narrowing the interval between the balls stored in the same pocket, and between adjacent pockets in the circumferential direction. In this case, the circumferential length of the pillar portion existing in is increased, and the number of balls is seven or more.

Conventionally, there is one in which two are stored in each pocket of the cage to suppress periodic fluctuation of the moment during rotation (Patent Document 2). That is, the thing of this patent document 2 makes the circumferential direction length of one window pillar large by making all the pockets of a cage into the long window which made the circumferential direction space | interval large.
Japanese Patent Laid-Open No. 11-303882 British patent 1537067

  In the thing of patent document 1, the circumferential direction length dimension of the pillar part which exists between pockets adjacent in the circumferential direction is enlarged by accommodating a plurality of balls in a pocket, and the durability of the cage In order to ensure, the durability of the constant velocity universal joint as a whole is improved. However, the one described in Patent Document 1 is based on the premise that the number of balls is seven or more, and in the case of having six balls, the load capacity decreases at high angles and the contact between the inner ring and the cage inner spherical surface. It is not intended to prevent an increase in surface pressure.

  Moreover, in the thing of patent document 2, two pieces are accommodated in each pocket of a cage, and like the said patent document 1, the whole number of pockets is decreased and the circumferential direction length of a window pillar is enlarged. . For this reason, even in this case, it is not possible to prevent a decrease in load capacity at a high angle and an increase in contact surface pressure between the inner ring and the cage inner spherical surface.

  In view of the above problems, the present invention can be downsized, and even when downsized, when the operating angle is taken, there is little reduction in load capacity, and the ball rides on the track at high angles. A fixed type constant velocity universal joint capable of improving high angle strength and durability by relaxing the above is provided.

  The fixed type constant velocity universal joint according to the present invention includes an outer member having a plurality of track grooves formed on an inner spherical surface, an inner member having a plurality of track grooves formed on the outer spherical surface, and a track groove of the outer member. A plurality of balls that are interposed between the track grooves of the inner member and the track groove of the inner member, and a cage that has a pocket for accommodating the balls and is interposed between the outer member and the inner member. In the fixed constant velocity universal joint provided, the cage pocket has four pairs of a pair of long pockets having a large circumferential interval and a pair of short pockets having a small circumferential interval. Are shifted 180 degrees along the circumferential direction, and the pair of short pockets are shifted 180 degrees along the circumferential direction, and the long pockets and the short pockets are alternately arranged along the circumferential direction. Accommodates balls and short The socket accommodates one ball, the end portion of the joint innermost side of the outer spherical surface of said inner member, and forming an arc portion continuing in a range corresponding to at least long pockets, in the circumferential direction.

  In the fixed type constant velocity universal joint of the present invention, the number of window columns between the pockets of the cage can be four, and the circumferential length of one window column can be increased. Thereby, the rigidity of each cage window column can be increased. Further, by having the long pocket, the inner ring can be easily assembled into the cage.

  In addition, by forming a circular arc portion that is continuous in the circumferential direction at the end of the inner spherical surface of the outer spherical surface of the inner member, the outer spherical surface of the inner member and the inner spherical surface of the cage are continuously connected at a high operating angle. Can be contacted.

  The pitch angle on the PCD of the two balls accommodated in the long pockets was made smaller than 60 degrees, and the pitch angles of the other balls were made larger than 60 degrees. Thereby, the distance between the pitches of the two balls stored in the long pocket is reduced, and the distance between the pitches of the track grooves of the outer member corresponding thereto is reduced.

  The axial length of the inner member was made shorter than the circumferential interval between the long pockets. This makes it easier to incorporate the inner member into the cage. Furthermore, the shoulder width dimension between the two track grooves of the outer member corresponding to the long pocket of the cage was set smaller than the pocket width in the cage axial direction. This facilitates the incorporation of the cage into the outer ring.

  The center of curvature of the track groove of the outer member and the center of curvature of the track groove of the inner member are offset in the axial direction by an equal distance from the joint center, and the center of curvature of the outer spherical surface of the cage and the cage The center of curvature of the inner spherical surface was offset in the axial direction by an equal distance from the joint center, and the offset amount of the cage was increased so as to be substantially the same as the offset amount of the track groove. As a result, it is possible to prevent the depth of the track groove on the deeper side of the joint from becoming shallow, and to increase the thickness (diameter thickness) of the cage on the opening side.

  In addition, as a fixed type constant velocity universal joint, even if the track groove bottoms of the inner member and the outer member are provided with arc portions and straight portions, the track groove bottoms of the inner member and the outer member are arc shapes. A part and a taper part may be provided.

  In the present invention, since the rigidity of each cage window column can be increased, a large ball can be disposed on a small PCD, and the size can be reduced without reducing the load capacity. Moreover, the cage can be prevented from being damaged by a torsional torque load at a high angle. Further, by having the long pocket, the inner ring can be easily assembled into the cage. In particular, by making the axial length of the inner ring shorter than the minimum length of the long pockets in the circumferential direction, the inner ring can be more easily assembled into the cage and the assembly workability can be improved.

  In addition, since the outer spherical surface of the inner member and the inner spherical surface of the cage can be continuously in contact with each other, the contact area between the outer spherical surface of the inner member and the inner spherical surface of the cage increases, and the contact surface pressure at that portion is reduced. Is done. For this reason, generation | occurrence | production of abrasion, a galling, a seizure, etc. can be prevented. Accordingly, it is possible to prevent malfunction of the joint, breakage, temperature rise, seizure, generation of abnormal noise, and the like.

  In addition, since the outer spherical surface of the inner member and the inner spherical surface of the cage are in contact at a high operating angle, the end portion (back end portion) of the inner member and the edge portion of the pocket frame (window frame) are in contact with each other. It is possible to prevent malfunction due to interference and chipping of the edge portion of the window frame, and it is possible to prevent joint failure and early breakage due to cage chipping.

  The distance between the pitches of the two balls stored in the long pocket can be reduced, and the distance between the pitches of the track grooves of the outer member corresponding thereto can be reduced. This facilitates the incorporation of the cage into the outer ring. In particular, the distance between the pitches (the shoulder width dimension between the track grooves) can be made smaller than the pocket width in the cage axial direction, which makes it easier to incorporate the cage into the outer ring and improve the assembly workability. it can.

  The cage offset has been increased to be approximately the same as the track groove offset, so that the depth of the track groove on the inner side of the joint can be prevented from decreasing, and the cage wall thickness (radial thickness) on the opening side can be prevented. Can be increased. For this reason, it is possible to prevent the ball at a high angle from riding on the track edge, and an excessive stress is not generated at the edge. In other words, the torsional torque load capacity at high angles is prevented from decreasing, and the high-angle durability life is improved (improved), and the breaking strength is improved (improved) due to plastic deformation of the inner and outer member track grooves at high angles. You can plan.

  Further, since the thickness (diameter thickness) of the cage on the joint opening side can be increased, the rigidity of the cage window frame on the joint opening side can be increased. For this reason, coupled with the increased rigidity of each cage window column, it is possible to greatly improve the cage breakage strength against a torsional torque load at a high angle.

  If two balls are stored in the long pocket, there is no window column between the balls. Therefore, it is necessary to increase the rigidity of the window frame on the joint opening side that receives a large load from the balls. As described above, by increasing the offset amount of the cage so as to be substantially the same as the offset amount of the track groove, the rigidity of the window frame on the joint opening side can be increased, and two balls are stored in the long pocket. Even with the structure, the strength of the cage can be sufficiently maintained.

Hereinafter, embodiments of the present invention will be described with reference to FIGS.

  As shown in FIG. 1, the fixed type constant velocity universal joint includes an outer ring 23 as an outer member in which a plurality of track grooves 22 are formed in the inner spherical surface 21 along the axial direction at unequal intervals in the circumferential direction. A plurality of track grooves 25 that are paired with the track grooves 22 of the outer ring 23 on the spherical surface 24 are formed along the axial direction at unequal circumferential intervals, and an inner ring 26 as an inner member, and the track grooves 22 of the outer ring 23 A plurality of balls 27 that transmit torque by being interposed between the track grooves 25 of the inner ring 26 and a cage 28 that is interposed between the inner spherical surface 21 of the outer ring 23 and the outer spherical surface 24 of the inner ring 26 to hold the balls 27. And.

  The track groove 22 of the outer ring 23 includes a back-side track groove 22a in which the track groove bottom is an arc portion and an opening-side track groove 22b in which the track groove bottom is a straight portion parallel to the outer ring axis. The back side track groove 22 a has its center of curvature O 1 shifted from the joint center O in the axial direction toward the opening side of the outer ring 23.

  The track groove 25 of the inner ring 26 includes a back side track groove 25a in which the track groove bottom is a straight portion parallel to the inner ring axis and an opening side track groove 25b in which the track groove bottom is an arc portion. In this case, as shown in FIG. 5, a range H formed by the back side track groove 25a and the opening side track groove 25b is a necessary track range where the ball 27 rolls. The center of curvature O2 of the opening-side track groove 25b is provided at an equal distance k away from the joint center O in the axial direction on the back side opposite to the center of curvature O1 of the back-side track groove 22a of the outer ring 23.

  A back groove portion 25 c that opens to the outer spherical surface 24 is connected to the back track groove 25 a. For this reason, a circular arc portion 36 continuous in the circumferential direction is formed at the end of the outer spherical surface 24 of the inner ring 26 on the joint back side. In this case, the arc portion 36 is formed over the entire circumference.

  In the cage 28, the center of curvature O3 of the outer spherical surface 28a and the center of curvature O4 of the inner spherical surface 28b are offset in the axial direction by an equal distance k2 with respect to the joint center (cage center) O. The amount is made substantially the same as the offset amount of the track groove.

  For this reason, the outer spherical surface 28a of the cage 28 can form a substantially concentric arc (a concentric arc having different curvature radii) with the groove bottom of the inner track groove 22a of the outer ring 23, and the track groove depth on the inner side of the joint. Can be prevented, and the thickness (diameter thickness) on the opening side of the cage 28 can be increased.

  The cage 28 is provided with a pocket 29 for accommodating the ball 27. In this case, as shown in FIG. 2, the pockets 29 of the cage 28 have four pairs of a pair of long pockets 30 having a large circumferential interval and a pair of short pockets 31 having a small circumferential interval. . Then, the pair of long pockets 30 are shifted 180 degrees along the circumferential direction, and the pair of short pockets 31 are shifted 180 degrees along the circumferential direction so that the long pockets 30 and the short pockets 31 are alternately positioned along the circumferential direction. Is arranged. For this reason, there are four window columns (cage window columns) 33 provided between the pockets. The long pocket 30 accommodates two balls 27 and the short pocket 31 accommodates one ball 27.

  The pitch angle e on the PCD of the two balls 27 accommodated in the long pocket 30 is made smaller than 60 degrees, and the pitch angle d of the other balls 27 is made larger than 60 degrees. Further, the axial length i (see FIG. 5) of the inner ring 26 is made shorter than the circumferential interval h (see FIG. 7) of the long pockets 30. Further, as shown in FIG. 8, the shoulder width dimension f between the two track grooves of the outer ring 23 corresponding to the long pocket 30 of the cage 28 is set smaller than the pocket width g in the cage axial direction.

  According to the fixed type constant velocity universal joint of the present invention, the number of the window pillars 33 between the pockets of the cage 28 can be four, and the circumferential length of each window pillar 33 can be increased. . As a result, the rigidity of each cage window column 33 can be increased, so that a large ball 27 can be arranged on a small PCD, and the fixed constant velocity universal joint can be made compact without reducing the load capacity. As a result, the cage 28 can be reduced in size, and the cage 28 can be prevented from being damaged by a torsional torque load at a high angle.

  By the way, since there is no window column between the two balls 27 of the long pocket 30, if the arc portion 36 is not provided in the inner ring 26, the outer spherical surface of the inner ring 26 is divided into six discontinuous portions by the six track grooves 25. Is done. For this reason, the contact area between the inner ring 26 corresponding to the portion without the window pillar and the cage window frame (pocket frame) is small, and the contact surface pressure is increased. When the operating angle becomes large (at a high angle), a range in which the cage inner spherical surface 28b and the outer spherical surface 24 of the inner ring 26 do not come into contact with each other is generated as shown in FIGS. That is, the contact between the inner ring 26 and the cage 28 becomes intermittent. For this reason, the cage 28 is easily deformed by the load torque. When the cage 28 is deformed, the end portion of the inner ring 26 interferes with the edge portion of the long pocket 30 (the edge portion on the inner spherical surface 28b side of the long side 35). If such interference occurs, it causes malfunction of the joint and chipping or cracking of the edge portion.

  On the other hand, if a circular arc portion 36 that is continuous in the circumferential direction is formed at the end of the outer spherical surface 24 of the inner ring 26 in the circumferential direction, as shown in FIG. 3, FIG. 9, and FIG. Even so, the inner spherical surface 28b of the cage and the outer spherical surface 24 of the inner ring 26 are always in contact with each other.

  Therefore, the force applied to the cage window frame is leveled, the deformation of the cage 28 is reduced, and the contact between the inner ring 26 and the cage 28 becomes continuous. That is, even at a high operating angle, the inner ring 26 and the cage inner spherical surface 28b can be continuously brought into contact with each other. Therefore, the contact area between the inner ring 26 and the cage inner spherical surface 28b is increased, and the contact surface pressure at that portion is increased. Alleviated. For this reason, generation | occurrence | production of abrasion, a galling, a burning, etc. can be prevented. Accordingly, it is possible to prevent malfunction of the joint, breakage, temperature rise, seizure, generation of abnormal noise, and the like.

  Moreover, since the outer spherical surface 24 of the inner ring 26 and the cage inner spherical surface 28b are in contact with each other at a high operating angle, the end portion (back end portion) of the inner member and the edge portion of the pocket frame (window frame) It is possible to prevent an abnormal operation due to the interference and chipping of the edge portion of the window frame, and it is possible to prevent malfunction of the joint and premature breakage due to the cage chipping.

  Further, since the long pocket 30 is provided, the inner ring 26 can be easily assembled into the cage 28. In particular, by making the axial length i of the inner ring 26 shorter than the circumferential interval h of the long pockets 30, the inner ring 26 can be more easily assembled into the cage 28 and the assembly workability can be improved. .

  That is, when the inner ring 26 is incorporated in the cage 28, the inner ring 26 is disposed so that the axis is perpendicular to the axis of the cage 28 (the state in which the inner ring 26 is rotated by 90 ° with respect to the cage 28). Then, a part of the outer spherical surface 24 of the inner ring 26 is dropped into the pocket 29 of the cage 28. In this state, the inner ring 26 is inserted into the cage 28, and then the inner ring 26 is rotated by 90 ° with respect to the cage 28. The axis of the inner ring 26 is aligned with the axis of the inner ring 26 and is placed in a normal posture. For this reason, when the inner ring 26 is assembled into the cage 28, a part of the outer spherical surface 24 of the inner ring 26 can be dropped into the long pocket 30 and the inner ring 26 can be easily assembled into the cage.

  Further, the distance between the pitches of the two balls 27 accommodated in the long pocket 30 can be reduced, and the distance between the pitches of the track grooves 22 of the outer ring 23 corresponding thereto can be reduced. This facilitates the incorporation of the cage 28 into the outer ring 23. In particular, the pitch distance (track groove shoulder width dimension f) can be made smaller than the pocket width g in the cage axis direction, which makes it easier to incorporate the cage 28 into the outer ring 23 and enhances assembly workability. Can be improved.

  Since the offset amount of the cage 28 is increased so as to be substantially the same as the offset amount of the track grooves 22 and 25, it is possible to prevent the depth of the track groove on the back side of the joint from becoming shallow and to prevent the meat of the cage 28 on the opening side. The thickness (thickness in the radial direction) can be increased. For this reason, it is possible to prevent the ball at a high angle from riding on the track edge, and an excessive stress does not act on the edge. In other words, the torsional torque load capacity at high angles is prevented from decreasing, and the high-angle durability life is improved (improved), and the breaking strength is improved (improved) due to plastic deformation of the inner and outer member track grooves at high angles. You can plan.

  Moreover, since the thickness (diameter direction thickness) of the cage 28 on the joint opening side can be increased, the rigidity of the cage window frame on the joint opening side can be increased. For this reason, coupled with the increased rigidity of each cage window column, it is possible to greatly improve the cage breakage strength against a torsional torque load at a high angle.

  If the two balls 27 are stored in the long pocket 30, the window pillar 33 does not exist between the balls 27. Therefore, it is necessary to increase the rigidity of the window frame on the joint opening side that receives a large load from the balls 27. However, as described above, by increasing the offset amount of the cage 28 so as to be substantially the same as the offset amount of the track grooves 22 and 25, the rigidity of the window frame on the joint opening side can be increased. Even in the structure in which the two balls 27 are accommodated in 30, the strength of the cage 28 can be sufficiently maintained.

  By the way, in the said embodiment, although it was an undercut free type | mold (UJ) which has the straight grooves 22b and 25a in the track grooves 22 and 25 as a fixed type constant velocity universal joint, it is a bar which does not have such a straight groove. Field type (BJ) may be used. Moreover, the track groove bottoms of the inner ring 26 and the outer ring 23 may be provided with an arc portion and a tapered portion. In this case, it is preferable to provide the taper portion of the track groove 22 of the outer ring 23 on the opening side and to expand from the back side toward the opening side. This is because the operating angle can be increased.

  In the embodiment, the arc portion 36 formed in the inner ring 26 is continuous over the entire circumference. However, such an arc portion 36 may not be provided in the track groove 25 corresponding to the short pocket 31. That is, it is only necessary to form the arc portion 36 for the track groove 25 corresponding to the long pocket 30. As described above, the provision of the long pocket 30 causes problems such as wear, galling, and seizure. The arc portion 36 is provided only for the track groove 25 corresponding to the long pocket 30. This is because such a problem can be solved.

  As described above, the embodiment of the present invention has been described. However, the present invention is not limited to the above-described embodiment, and various modifications are possible. For example, in the embodiment, the curvature center O1 and the curvature center O3 are slightly different. Although the center of curvature O2 and the center of curvature O4 are disposed at positions slightly deviated from each other, the center of curvature O2 is provided even if the center of curvature O1 and the center of curvature O3 are the same position. And the center of curvature O4 may be at the same position. In addition, when the curvature center O1 and the curvature center O3 are deviated or the curvature center O2 and the curvature center O4 are deviated, the deviation amount can be arbitrarily set, but the offset amount k and the deviation amount (k−k2). The ratio is preferably set as (k−k2) /k≦0.3. When (k−k2) / k> 0.3, there is no difference from the conventional fixed type constant velocity universal joint shown in FIG. 14, the depth of the track groove on the inner side of the joint becomes shallower, and the cage 28 on the opening side becomes smaller. It becomes impossible to increase the wall thickness of the joint, which is below the required strength of the joint (see FIG. 16).

  Further, the circumferential interval h of the long pockets 30 can be set in various ways within a range in which the ease of assembling the cage 28 into the inner ring 26 can be improved and the rigidity of the window pillar 33 is not lowered. Furthermore, the track groove shoulder width dimension f, the pocket width g of the cage 28 in the cage axial direction, and the like can be set in consideration of the ease of incorporation of the cage 28 into the outer ring 23 and the like.

  The axial length of the arc portion 36 of the inner ring 26 can be arbitrarily set within a range that does not impair the rolling of the ball 27 that rolls in the track groove 25.

It is sectional drawing of the fixed type constant velocity universal joint which shows embodiment of this invention. It is principal part sectional drawing of the said fixed type constant velocity universal joint. It is sectional drawing of the state in which the said fixed type constant velocity universal joint took the operating angle. It is a front view of the inner ring | wheel of the said fixed type constant velocity universal joint. FIG. 5 is a sectional view taken along line B-O-B ′ of FIG. 4. It is a perspective view of the inner ring | wheel of the said fixed type constant velocity universal joint. It is sectional drawing of the cage of the said fixed type constant velocity universal joint. It is sectional drawing which shows the relationship between the outer ring | wheel of the said constant velocity universal joint, and a cage. It is a perspective view which shows the relationship between an inner ring | wheel and a cage when the said fixed type constant velocity universal joint takes an operating angle. It is the perspective view seen from the other direction which shows the relationship between an inner ring | wheel and a cage when the said fixed type constant velocity universal joint takes an operating angle. It is a perspective view which shows the relationship between an inner ring | wheel and a cage at the time of taking the operating angle of the constant velocity universal joint which does not have an arc part in an inner ring | wheel. It is the perspective view seen from the other direction which shows the relationship between an inner ring | wheel and a cage at the time of taking the operating angle of the constant velocity universal joint shown in the said FIG. It is sectional drawing at the time of taking the operating angle of the constant velocity universal joint shown in the said FIG. It is a longitudinal cross-sectional view of the conventional constant velocity universal joint. It is a cross-sectional view of a conventional constant velocity universal joint. It is a figure which shows the relationship between offset amount k and deviation | shift amount (k-k2).

Explanation of symbols

21 inner spherical surface 22 track groove 24 outer spherical surface 25 track groove 27 ball 28 cage 28b cage inner spherical surface 28b inner spherical surface 28a outer spherical surface 29 pocket 30 long pocket 31 short pocket 36 arc portion

Claims (6)

An outer member having a plurality of track grooves formed on the inner spherical surface, an inner member having a plurality of track grooves formed on the outer spherical surface, and between the track grooves of the outer member and the track grooves of the inner member. In a fixed type constant velocity universal joint including a plurality of balls interposed and transmitting a torque, and a cage having a pocket for accommodating the balls and interposed between an outer member and an inner member,
The cage pocket has four pairs of a pair of long pockets having a large circumferential interval and a pair of short pockets having a small circumferential interval, and the pair of long pockets are shifted by 180 degrees along the circumferential direction. In addition, the pair of short pockets are shifted 180 degrees along the circumferential direction, the long pockets and the short pockets are alternately arranged along the circumferential direction, and the two pockets are accommodated in the long pockets. Is characterized in that one ball is accommodated, and a circular arc portion that is continuous in the circumferential direction is formed in an end portion of the outer spherical surface of the inner member on the joint back side at least in a range corresponding to the long pocket. Fixed constant velocity universal joint.   2. The fixed constant velocity universal joint according to claim 1, wherein the arc portion is continuous with the entire circumference of the inner member in the circumferential direction.   2. The pitch angle on the PCD of the two balls accommodated in the long pocket is made smaller than 60 degrees, and the pitch angle of the other balls is made larger than 60 degrees. 2 fixed constant velocity universal joints.   The fixed constant velocity universal joint according to any one of claims 1 to 3, wherein an axial length of the inner member is shorter than a circumferential interval of the long pockets.   The fixed type according to any one of claims 1 to 4, wherein a shoulder width dimension between two track grooves of the outer member corresponding to the long pocket of the cage is set smaller than a pocket width in the cage axial direction. Constant velocity universal joint.   The center of curvature of the track groove of the outer member and the center of curvature of the track groove of the inner member are offset in the axial direction by an equal distance from the joint center, and the center of curvature of the outer spherical surface of the cage and the cage 2. The center of curvature of the inner spherical surface is offset in the axial direction by an equal distance from the joint center, and the offset amount of the cage is increased to be substantially the same as the offset amount of the track groove. The fixed type constant velocity universal joint according to claim 5.

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