JP5143493B2 - Fixed constant velocity universal joint - Google Patents

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.

  For example, as shown in FIGS. 21 and 22, the BJ type fixed type constant velocity universal joint is an outer member in which a plurality of track grooves 2 are formed in the inner spherical surface 1 along the axial direction at equal intervals in the circumferential direction. An outer ring 3, an inner ring 6 as an inner member in which a plurality of track grooves 5 paired with the track grooves 2 of the outer ring 3 are formed on the outer spherical surface 4 along the axial direction at equal intervals in the circumferential direction, and the outer ring 3 Between the track groove 2 of the inner ring 6 and the track groove 5 of the inner ring 6 to transmit torque, and between the inner spherical surface 1 of the outer ring 3 and the outer spherical surface 4 of the inner ring 6, the balls 7 And a cage 8 for holding the The cage 8 is provided with a plurality of pockets 9 for accommodating the balls 7 along the circumferential direction.

  The center of curvature O1 of the track groove 5 of the inner ring 6 and the center of curvature O2 of the track groove 2 of the outer ring 3 are offset in the axial direction by an equal distance F and F with respect to the joint center O (track offset).

In recent years, in order to reduce the size, there is one in which eight balls are used as shown in FIG. 22 (Patent Document 1). In this case, the ratio between the pitch circle diameter of the ball and the diameter of the ball is set to a predetermined value. Here, the pitch circle diameter of the ball is 2 × PCR. PCR is the length of the line segment connecting the center of the track groove of the outer ring or the center of the track groove of the inner ring and the center of the ball.
Japanese Patent No. 3859264

  In the one described in Patent Document 1, the ball size is reduced and the number of balls is increased as compared with the six constant velocity universal joints. That is, by reducing the ball size, the torque load level that one ball can accept is also reduced. To compensate for this, the number of balls is increased from six to eight.

  However, if an attempt is made to further reduce the outer diameter of the constant velocity universal joint and increase the number of balls, the column width (circumferential length) between the pockets of the cage (cage) will be reduced. . The rigidity of the cage column is important in securing joint strength (joint strength) at high operating angles.

  For this reason, constant velocity universal joints with 8 balls will not have room for strength at high operating angles if the wall thickness of the column is made thinner than the current setting. difficult.

  In view of the above-mentioned 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 on the track edge portion at high angles Provided is a fixed type constant velocity universal joint that can improve the high angle strength and durability by mitigating the run-up.

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 type constant velocity universal joint provided, the number of the balls is six, the ratio of the pitch circle diameter of the balls to the diameter of the balls is 3.0 or more and 3.3 or less , and the outer member The ratio of the outer diameter of the ball to the diameter of the ball is 4.6 to 4.8, and 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 and cage The center of curvature of the outer spherical surface of the cage and the center of curvature of the inner spherical surface of the cage are offset in the opposite axial direction by an equal distance from the joint center, and the offset amount of the center of curvature of the outer member track groove and the inner member 0 <(k−k2) / k, where k is the offset amount of the center of curvature of the track groove and k2 is the offset amount of the center of curvature of the outer spherical surface of the cage and the offset amount of the center of curvature of the inner spherical surface of the cage. Assuming ≦ 0.3, the offset amount of the cage is increased .

  In the fixed type constant velocity universal joint of the present invention, since the number of balls is six, relatively large balls can be used, and the column width between the pockets of the cage can be increased. By setting the ratio between the pitch circle diameter of the ball and the ball diameter to 3.0 or more and 3.3 or less, the strength and durability of the constant velocity universal joint can be ensured.

  When the ratio of the pitch circle diameter to the ball diameter is r1, if r1 <3.0, if the ball diameter is large, the thickness of the inner member becomes too thin and there is a concern in terms of strength. When the pitch circle diameter of the ball is small, the surface pressure between the inner member (inner ring) / outer member (outer ring) and the ball increases, which raises concerns about durability. On the other hand, if r1> 3.3, when the ball diameter is small, the load capacity of the ball is small, and there is a concern in terms of durability. When the pitch circle diameter of the ball is large, outside the outer member The diameter becomes large and compactness cannot be achieved.

  The ratio between the outer diameter of the outer member and the ball diameter is preferably 4.6 or more and 4.8 or less. When the ratio r2 between the outer diameter of the outer member and the diameter of the ball is r2, if r2 <4.6, the thickness of the outer member becomes too thin when the ball diameter is large. When the outer diameter of the outer member is small, the surface pressure between the inner member / outer member and the ball increases, and there is a concern in terms of durability. On the contrary, when r2> 4.8, when the ball diameter is small, the load capacity of the ball is small, and there is a concern in terms of durability, and when the outer member has a large outer diameter, downsizing is achieved. Can not.

0 <By setting the (k-k2) /k≦0.3, it can be prevented from becoming shallow track groove depth of the joint Teoku side, the wall thickness of the cage on the opening side (radial direction thickness) Can be increased.

  The track grooves of the inner member and the track grooves of the outer member may be arranged at unequal pitches in the circumferential direction. If the track grooves are arranged at unequal pitches in the circumferential direction, the cage pockets are also arranged at unequal pitches in the circumferential direction. For this reason, a long pocket with a large circumferential interval is formed. Accordingly, the pocket having a large circumferential length can be used, and when the inner ring is assembled into the cage, the pocket having a large circumferential length can be used during the assembly.

  That is, when the inner ring is assembled in the cage, the outer ring of the inner ring is arranged in a state where the inner ring is arranged perpendicular to the axis of the cage (the inner ring is rotated by 90 ° with respect to the cage). A part of the inner ring (projection between track grooves) is dropped into the pocket of the cage, the inner ring is inserted into the cage in this state, and then the inner ring is rotated by 90 ° with respect to the cage, and the axis of the inner ring 6 is aligned with the axis of the cage. Generally, a method of aligning and arranging in a normal posture is used. For this reason, a pocket having a large circumferential length can be a pocket into which a part of the outer spherical surface of the inner ring is dropped.

  Further, it 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 (by omitting the column portion between balls having a small pitch) The long pockets 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. It is preferable to accommodate two balls and to accommodate one ball in the short pocket.

  The pitch angle on the PCD of the two balls accommodated in the long pocket can be made smaller than 60 degrees, and the pitch angle of the other balls can be 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.

  It is possible to provide a bulging portion that protrudes toward the inside of the long pocket on at least one of the long sides facing the long pocket, and to provide two ball housing portions that are connected to the long pocket via a slit.

  It is also preferable to provide a notch at the back end of at least one track groove of the inner member. By providing this notch, the inner member can be rotated starting from this notch when incorporated in the inner member, and the radius of rotation of the inner member can be reduced. Therefore, a larger space can be secured between the inner diameter of the cage and the inner member, and the cage diameter of the cage can be set smaller accordingly.

  As constant velocity universal joints, 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 portions and tapered portions. May be provided.

  In the present invention, since a relatively large ball can be used, an allowable torque capacity of one ball can be secured, and the ball can be arranged in a small PCD, that is, the outer diameter can be made compact. Moreover, since the thickness of the column portion between the pockets of the cage can be increased, the strength at a high operating angle can be ensured.

  In particular, by setting the ratio of the pitch circle diameter of the ball to the diameter of the ball to be 3.0 or more and 3.3 or less, the strength and durability as a constant velocity universal joint can be ensured, and high precision, etc. A quick universal joint can be provided. Further, when the ratio between the outer diameter of the outer member and the diameter of the ball is set to 4.6 or more and 4.8 or less, further strength and durability can be secured.

  Since the track groove offset is reduced and the cage (cage) offset amount is increased, it is possible to prevent the depth of the track groove on the inner side of the joint from being reduced, and the cage thickness (diameter thickness) on the opening side. 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 applied to 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. Can be planned.

  If the track grooves of the inner member and the track grooves of the outer member are arranged at unequal pitches in the circumferential direction, the cage pockets are also arranged at unequal pitches in the circumferential direction. As a result, when the inner ring is assembled in the cage, a pocket having a large circumferential length can be used during the assembly, and the assemblability can be improved.

  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. Is shifted 180 degrees along the circumferential direction, and the long pockets and the short pockets are alternately arranged along the circumferential direction, so that the number of column portions between the pockets of the cage can be four. Further, by making the pitch angle on the PCD of the two balls accommodated in the long pockets smaller than 60 degrees and making the pitch angle of the other balls larger than 60 degrees, The circumferential length can be increased. Thereby, the rigidity of a cage pillar part can be enlarged.

  By providing the bulging portion, the rigidity of the frame (window frame) for constituting the long pocket can be improved. As a result, the cage can be prevented from being deformed due to insufficient rigidity of the window frame, and the operability of the joint can be prevented from being impaired, and stable operability can be exhibited over a long period of time.

  When the bulging part is provided on the long side on the joint opening side, the interference between the inlay edge part of the opening (inlet) of the outer member and the pocket edge part on the cage outer spherical surface side should be delayed or eliminated. When the bulging part is provided on the long side on the back side of the joint, interference between the back side edge part of the outer spherical surface of the inner member and the pocket edge part on the spherical surface side of the cage should be delayed or eliminated. Can do. For this reason, it becomes easy to guide the cage to the inner spherical surface of the outer member and the outer spherical surface of the inner member, it is possible to prevent deterioration of the operability of the joint, and to prevent deterioration of the operability of the joint by improving the rigidity of the window frame. Together, it can effectively prevent the cage from cracking and cracking.

  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.

  By providing a notch at the back end of at least one track groove of the inner member, the inner member can be rotated from the notch when the inner member is assembled. The radius can be reduced. Therefore, a larger space can be secured between the inner diameter of the cage and the inner member, and the cage diameter of the cage can be set smaller accordingly. As a result, the cross-sectional area of the inlay side of the cage can be enlarged, the rigidity of the thin side frame portion of the cage can be improved, and the spherical contact area can be secured, so that the contact surface It is possible to prevent an increase in pressure, avoid heat generation and decrease in durability, and further avoid deformation of cage and decrease in strength. That is, the rigidity of the cage can be improved without reducing the load capacity and spherical area of the inner member.

  If the track groove bottoms of the inner member and the outer member have arc portions and straight portions, the joint operating angle can be increased. In particular, if the track groove bottom has an arc portion and a taper portion, the angle can be further increased.

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

  As shown in FIG. 1, this fixed type constant velocity universal joint has an outer ring as an outer member in which a plurality (six) of track grooves 22 are formed on the inner spherical surface 21 along the axial direction at irregular circumferential intervals. 23, and an inner ring 26 as an inner member in which a plurality (six) of track grooves 25 that are paired with the track grooves 22 of the outer ring 23 are formed on the outer spherical surface 24 along the axial direction at unequal circumferential intervals. A plurality of (six) balls 27 that are interposed between the track groove 22 of the outer ring 23 and the track groove 25 of the inner ring 26 and transmit torque, and the inner spherical surface 21 of the outer ring 23 and the outer spherical surface 24 of the inner ring 26. And a cage 28 having a pocket 29 for holding a ball 27 interposed therebetween. In this case, as shown in FIG. 2, six pockets 29 are arranged at an equal pitch (60 ° pitch) along the circumferential direction.

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. 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 far side opposite to the center of curvature O1 of the back side track groove 22a of the outer ring 23.

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. Here, substantially the same means that the offset amount of the center of curvature O1 of the track groove 22 of the outer ring 23 and the offset amount of the center of curvature O4 of the track groove 25 of the inner ring 26 are k, and the center of curvature O3 of the outer spherical surface 28a of the cage 28 is k. This is a range where 0 <(k−k2) /k≦0.3, where k2 is the offset amount and the offset amount of the center of curvature O4 of the inner spherical surface 28b of the cage 28.

  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.

As shown in FIG. 2, the ratio r1 between the pitch circle diameter PCD _BALL of the ball 27 and the diameter D _{BALL of the} ball 27 was set to 3.0 or more and 3.3 or less. That is, 3.0 ≦ r1 ≦ 3.3. The ratio r2 between the outer diameter D _OUTER of the outer ring 23 and the diameter D _{BALL of the} ball 27 was set to 4.6 or more and 4.8 or less. That is, 4.4 ≦ r2 ≦ 4.8.

Here, the pitch circle diameter PCD _BALL is 2 × (the length of a line segment connecting the center of the track groove of the outer ring or the center of the track groove of the inner ring and the center of the ball), and the locus of the circle drawn by the ball center Is the diameter.

  In the present invention, since the number of balls 27 is six, relatively large balls 27 can be used, and the thickness of the pillar portion 33 between the pockets 29 of the cage 28 can be increased. By setting the ratio between the pitch circle diameter of the balls 27 and the diameter of the balls to be 3.0 or more and 3.3 or less, the strength and durability as a constant velocity universal joint can be ensured.

  When the ratio between the pitch circle diameter and the diameter of the ball 27 is r1, if r1 <3.0, if the ball diameter is large, the inner ring 26 becomes too thin, which is a concern in terms of strength. When the pitch circle diameter of the ball is small, the surface pressure between the inner / outer rings 26 and 23 and the ball increases, and there is a concern in terms of durability. On the contrary, when r1> 3.3, when the diameter of the ball 27 is small, the load capacity of the ball 27 is small, and there is a concern in terms of durability, and when the pitch circle diameter of the ball 27 is large, the outer ring Since the thickness of 23 becomes too thin, there is a concern in terms of strength, or the outer diameter of the outer ring becomes large, so that compactness cannot be achieved.

  The ratio between the outer diameter of the outer ring 23 and the diameter of the ball 27 is preferably 4.6 or more and 4.8 or less. When the ratio r2 between the outer diameter of the outer ring 23 and the diameter of the ball 27 is r2, if r2 <4.6, if the diameter of the ball 27 is large, the thickness of the outer ring 23 becomes too thin, and the strength is increased. When the outer diameter of the outer ring 23 is small, the surface pressure between the inner / outer rings 26 and 23 and the ball increases, and there is a concern in terms of durability. On the other hand, if r2> 4.8, when the diameter of the ball 27 is small, the load capacity of the ball is small, and there is a concern in terms of durability, and when the outer diameter of the outer ring 23 is large, the compactness is reduced. Cannot be achieved.

  In the present invention, the center of curvature O1 of the track groove 22 of the outer ring 23 and the center of curvature O2 of the track groove 25 of the inner ring 26 are offset in the axial direction by an equal distance from the joint center O, and the cage The center of curvature O3 of the outer spherical surface 28a of 28 and the center of curvature O4 of the inner spherical surface 28b of the cage 28 are offset in the axial direction by an equal distance from the joint center O, and the offset amount of the cage 28 is set to the track groove. The offset amounts 22 and 25 are substantially the same as the offset amounts. Thus, in the present invention, since the offset of the track groove grooves 22 and 25 is reduced and the offset amount of the cage (retainer) 28 is increased, it is possible to prevent the depth of the track groove on the joint back side from becoming shallow, The wall thickness (diameter thickness) of the cage 28 on the opening side can be increased. For this reason, it is possible to prevent the ball 27 at a high angle from riding on the track edge, and an excessive stress does not act on the edge. That is, a reduction in torsional torque load capacity at high angles is prevented, and high angle durability life is improved (improved), and breakage strength is improved (improved) due to plastic deformation of the track grooves 22 and 25 of the inner ring 26 and outer ring 22 at high angles. Can be achieved.

  FIG. 3 shows a modification of the cage 28. In this case, the cage 28 includes four pairs 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 column portions (cage column portions) 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. For this reason, as shown in FIG. 4, 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. Further, as shown in FIG. 5, the axial length i of the inner ring 26 is made shorter than the circumferential interval h of the long pocket 30.

  By the way, as shown in FIGS. 4 and 5, the long pocket 30 has a bulging portion 36 projecting inwardly of the long pocket at the center in the longitudinal direction of the long sides 35 a and 35 b facing the long pocket 30. 36 is provided to form two ball accommodating portions 38, 38 connected to the long pocket 30 through the slit 37. In addition, the bulging portions 36, 36 are continuous spherical surfaces having the same curvature radius as the outer spherical surface 28 a of the cage 28, and the inner surfaces are continuous spherical surfaces having the same curvature radius as the inner spherical surface 28 b of the cage 28. In this embodiment, the shape of the bulging portion 36 is a trapezoidal shape (so-called Mt. Fuji shape) whose side is an arc surface when viewed from the cage outer peripheral side. For this reason, the projecting end surface 36a of each bulging portion 36 is a plane extending along the circumferential direction of the cage, and is opposed (facing) with a predetermined interval M.

  As shown in FIG. 5, the predetermined interval M is set to a size that does not interfere with the shoulder 47 (protrusion between adjacent track grooves) of the inner ring 26 during assembly. Also, the size and shape of the bulging portion 36 must be such that the movement of the ball 27 accommodated in the ball accommodating portion 38 is not hindered when rotating with an operating angle. The bulging portion 36 can be formed by machining or plastic working when the long pocket 30 is formed.

  As described above, there are four pairs of the long pockets 30 having a large circumferential interval and the pair of short pockets 31 having a small circumferential interval, and the pair of long pockets 30 are shifted by 180 degrees along the circumferential direction. In addition, the pair of short pockets 31 are shifted 180 degrees along the circumferential direction, and the long pockets 30 and the short pockets 31 are alternately arranged along the circumferential direction. The number can be four, and the circumferential length of one pillar 33 can be increased.

  As a result, the rigidity of each cage post 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. Further, since the long pocket 30 is provided, the inner ring 26 can be easily assembled into the cage 28. That is, as shown in FIGS. 5 and 6, when the inner ring 26 is assembled into the cage 28, one shoulder 47 of the inner ring 26 is dropped into one long pocket 30, so that the pocket 29 into which the shoulder 47 is dropped is inserted. In addition, by using the long pocket 30, the workability can be improved.

  By providing the bulging portions 36 and 36 in the long pocket 30, the rigidity of the frame (window frame) for constituting the long pocket 30 can be improved. As a result, deformation of the cage 28 due to insufficient rigidity of the window frame can be prevented, and the operability of the joint can be maintained, and stable operability can be exhibited over a long period of time.

  Further, when the operating angle is taken by the bulging portion 36 on the long side 35a side on the joint opening side, interference between the inlay edge portion of the opening (inlet) of the outer ring 23 and the pocket edge portion on the cage outer spherical surface 28a side is prevented. The bulging portion 36 of the long side 35b on the back side of the joint can be delayed or eliminated, and interference between the back side edge portion of the outer spherical surface 24 of the inner ring 26 and the pocket edge portion on the cage inner spherical surface 28b side is delayed. Or can be lost. For this reason, it becomes easy to guide to the inner spherical surface 21 of the outer member of the cage 28 and the outer spherical surface 24 of the inner member, so that the operability of the joint can be prevented from being deteriorated, and the operability of the joint is improved by improving the rigidity of the window frame. Combined with the prevention of deterioration, chipping and cracking of the cage 28 can be effectively prevented.

  In the long pocket 30 of the above embodiment, as shown in FIG. 7 (a), the bulging portions 36, 36 have a so-called Mt. Fuji shape, but in the shape as shown in FIGS. 7 (b), (c), and (b). There may be. That is, the bulging portions 36 and 36 in FIG. 7B are rounded at the corners of the protruding end surface 36a of the bulging portion 36, and the bulging portions 36 and 36 in FIG. Is a gentle trapezoidal shape, and the expansion portions 36 and 36 in FIG. 7D are rectangular.

  Even the cage 28 having the long pocket 30 shaped as shown in FIGS. 7B, 7C and 7B has the same effects as the cage 28 shown in FIG.

  Moreover, as shown in FIG. 8, you may abbreviate | omit either one of a pair of bulging parts 36 and 36. As shown in FIG. In FIG. 8A, the bulging portion 36 is provided only on the long side 35a side on the joint opening side, and in FIG. 8B, the bulging portion 36 is provided only on the long side 35b side on the joint opening side.

  That is, in the case shown in FIG. 8A, interference between the inlay edge portion of the opening (inlet) of the outer ring 23 and the pocket edge portion on the cage outer spherical surface 28a side can be delayed or eliminated. In the case shown in (b), the interference between the inner edge 26 of the outer spherical surface 24 of the outer spherical surface 24 and the pocket edge portion of the inner spherical surface 28b of the cage can be delayed or eliminated.

  Moreover, as shown in FIG. 9 and FIG. 10, it is good also as an oblong hole which does not provide the bulging part 36 in the long pocket 30. FIG. In such a thing, although the effect based on the bulging part 36 cannot be enjoyed, the improvement in the incorporating property to the cage 28 of the inner ring | wheel 26 and a lightweight improvement can be achieved.

  As shown in FIGS. 11 to 13, a notch 45 may be provided at the back end of one track groove 25 (25 </ b> A) of the inner ring 26. In this case, the notch 45 is formed by a tapered surface formed at a corner portion between the rear side end and the inner ring end surface 46. Note that the notch 45 may be formed by machining or plastic processing.

  By the way, when the inner ring 26 is incorporated into the cage 28, the inner ring 26 is disposed so that the axis is perpendicular to the axis of the cage 28 (a state in which the inner ring 26 is rotated by 90 ° with respect to the cage 28). To do. In this state, as shown in FIG. 14, a part of the outer spherical surface 24 of the inner ring 26 (protrusion 47A between the track grooves 25 adjacent in the circumferential direction) is dropped into the pocket 29 (long pocket 30) of the cage 28. That is, the track groove 25A in which the notch 45 is formed is fitted to the side frame portion 48 on the thinner side than the pocket 30, and the protrusion 47A on the counterclockwise side from the track groove 25A is connected to the pocket 30 of the cage 28. The inner ring 26 is rotated in the direction of the arrow X around the bottom of the notch 35. At this time, the rotation radius C can be made smaller than the rotation radius B without the notch 45 (the rotation radius of the conventional product). Here, the rotation radius C is a dimension between the bottom center portion of the notch 45 and one opening edge 50 of the track groove 25B opposite to the track groove 25A by 180 degrees.

  For this reason, when the inlay diameter of the cage 28 is A, the rotational radius of the inner ring 26 is B, and the product of the present invention is C, B> C, and therefore A−B <A−C. Thereby, the inlay diameter A of the product of the present invention can be made smaller than that of the conventional product, and the thickness of the thin side frame portion 48 can be increased.

  After the inner ring 26 is fitted in the cage 28, the inner ring 26 is rotated 90 ° with respect to the cage 28, and the axis of the inner ring 26 is aligned with the axis of the cage 28 and placed in a normal posture. As a result, the inner ring 26 can be incorporated into the cage 28.

  Since the notch 45 is provided at the inner end of the track groove 25, the inner ring 26 can be rotated with the notch 45 as a starting point when assembled in the cage 28, and the radius of rotation of the inner ring 26 can be reduced. Can do. For this reason, a larger space can be secured between the inner diameter of the cage 28 and the inner ring 26, and accordingly, the inner diameter of the cage 28 can be set smaller. As a result, the cross-sectional area on the inlay side of the cage 28 can be increased, the rigidity of the thin side frame portion 48 of the cage 28 can be improved, and a spherical contact area can be ensured. An increase in surface pressure can be prevented, heat generation and a decrease in durability can be avoided, and further, deformation of the cage 28 and a decrease in strength can also be avoided. That is, the rigidity of the cage 28 can be improved without reducing the load capacity and the spherical surface area of the inner ring 26. In addition, since the area of the inner spherical surface 28b of the cage 28 can be increased, the contact area of the inner ring 26 with the outer spherical surface 24 can be increased, and there is an advantage that the durability is stabilized in addition to the improvement in rigidity.

  The size of the notch 45 can be changed within a range in which the radius of rotation of the inner ring 26 when the inner ring 26 is assembled into the cage 28 can be reduced. However, if the size is too large, the inner ring 26 may have insufficient strength or the track groove 25 If the ball rolling range becomes small or is too small, the turning radius cannot be made too small.

  Next, FIGS. 15 to 17 show a case where a notch 45 is formed at the back end of all track grooves 25. For this reason, even in the case of this inner ring 26, as in the case of the inner ring 26 shown in FIGS. 11 to 13, when the inner ring 26 is assembled, the inner ring 26 can be rotated with the notch 45 as a starting point. Can be reduced. For this reason, the inner ring 26 shown in FIGS. 15 to 17 has the same effect as the inner ring 26 shown in FIGS. 11 to 13.

  In particular, since the notch 45 is formed at the back end of all the track grooves 25, any protrusion 47 may be inserted into the pocket 30 when the inner ring 26 is assembled into the cage 28. For this reason, there exists an advantage which can aim at the improvement of an incorporating property.

  By the way, in each of the above-described embodiments, the notch portion 45 is formed by a tapered surface that gradually decreases in diameter from the opening-side track groove 25b side toward the inner ring end face 46 side. As the notch portion 45, FIG. ) The shape shown in (b) may be used. The cutout 45 shown in FIG. 18A has a concave round shape, and the cutout 45 shown in FIG. 18B has a convex round shape.

  Even when the cutout 45 shown in FIGS. 18A and 18B is incorporated, the inner ring 26 can be rotated with the cutout 35 as a starting point, and the rotation radius of the inner ring 26 can be reduced. it can. Further, as shown in FIGS. 19A and 19B, the notch 45 may be formed at a part of the track groove end (the bottom in the example).

  Next, FIG. 20 shows another embodiment. In this case, the track groove bottoms of the inner ring 26 and the outer ring 23 are provided with an arc portion and a tapered portion. In other words, the track groove bottom 22c includes an inner side track groove 22c having a circular arc portion as a track groove bottom, and an opening side track groove 22d in which the track groove bottom is inclined from the back side toward the opening side toward the outer diameter side. The back side track groove 22c has its curvature center O1 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 25c in which the track groove bottom is inclined from the opening side toward the back side toward the outer diameter side, and an opening side track groove 25d in which the track groove bottom is an arc portion. Become. 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 far side opposite to the center of curvature O1 of the back side track groove 22a of the outer ring 23.

  Also in this case, the center of curvature O3 of the outer spherical surface 28a of the cage 28 and the center of curvature O4 of the inner spherical surface 28b of the cage 28 are offset in the axial direction by an equal distance with respect to the joint center O. The offset amount is substantially the same as the offset amount of the track grooves 22 and 25.

  Other configurations of the fixed type constant velocity universal joint of FIG. 20 are the same as those of the fixed type constant velocity universal joint shown in FIG. 1, and the same members are denoted by the same reference numerals as those in FIG. .

  For this reason, the fixed type constant velocity universal joint shown in FIG. 20 has the same effects as the fixed type constant velocity universal joint shown in FIG. In FIG. 1, by adopting an undercut free type in which the track groove bottoms of the inner ring 26 and the outer ring 26 are provided with an arc portion and a straight portion, the joint operating angle can be increased. On the other hand, if the track groove bottom has an arc portion and a taper portion as in the fixed type constant velocity universal joint shown in FIG. 20, the angle can be further increased.

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. while being disposed in a position displaced to have been arranged in slightly offset positions from the center of curvature O2 and the center curvature O4, displacement amount of that can be set arbitrarily, the offset amount k and the deviation amount ( The ratio with k−k2) is preferably (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. 21, the track groove depth on the back side of the joint becomes shallow, and the cage 28 on the opening side becomes small. It becomes impossible to increase the wall thickness of the joint, which is less than the required strength of the joint.

  Further, the circumferential interval h between 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 column portion 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 protruding end surface 36a of the bulging portion 36 may be a curved surface without being a flat surface.

  In the fixed type constant velocity universal joint shown in FIG. 20, a cage 28 having a long pocket 30 as shown in FIGS. 7 to 10 may be used. Moreover, you may use the inner ring | wheel 26 which has the notch part 45 as shown to FIG. 11 and FIG.

  As shown in FIG. 3 and the like, when the track grooves 25 of the inner ring 26 and the track grooves 22 of the outer ring 23 are arranged at unequal pitches in the circumferential direction, the balls 27 are arranged at unequal pitches in the circumferential direction. It will be. For this reason, in the embodiment, two balls arranged at less than 60 ° are accommodated in one long pocket 30. In other words, the shape is such that the column portion between two balls disposed at less than 60 ° is omitted. On the other hand, this pillar part may not be omitted. In this case, as shown in FIG. 1, six pillar parts are formed, and the strength of the entire cage is improved. Increases rigidity.

It is a longitudinal cross-sectional view of the fixed type constant velocity universal joint which shows embodiment of this invention. It is a cross-sectional view of the fixed type constant velocity universal joint. It is a cross-sectional view of the fixed type constant velocity universal joint which shows other embodiment of this invention. It is a front view which shows the relationship between the outer ring | wheel of the fixed type constant velocity universal joint shown in FIG. 3, and a cage. It is a side view which shows the relationship between the inner ring | wheel of a fixed type constant velocity universal joint shown in FIG. 3, and a cage. FIG. 4 is a side view showing an assembled state of the inner ring in the cage of the fixed type constant velocity universal joint shown in FIG. 3. It is sectional drawing of the inner ring | wheel of the said fixed type constant velocity universal joint. FIG. 4A is a side view of the cage of the fixed type constant velocity universal joint shown in FIG. 3, FIG. 4B is a side view showing a first modification, and FIG. It is a side view which shows an example, (d) It is a side view which shows a 3rd modification. The cage is shown, (a) is a side view showing a fourth modification, and (b) is a side view showing a fifth modification. It is a side view which shows the 6th modification of a cage. It is a perspective view which shows the 6th modification of a cage. It is a perspective view which shows the modification of an inner ring | wheel. It is a front view of the inner ring | wheel shown in the said FIG. It is sectional drawing of the inner ring | wheel shown in the said FIG. FIG. 13 is a cross-sectional view showing a method for incorporating the cage into the cage using the inner ring shown in FIG. 12. It is a perspective view which shows the other modification of an inner ring | wheel. FIG. 16 is a front view of the inner ring shown in FIG. 15. It is sectional drawing of the inner ring | wheel shown in the said FIG. The notch part in which an inner ring | wheel is formed is shown, (a) is an expanded sectional view which shows a 1st modification, (b) is an expanded sectional view which shows a 2nd modification. The notch part in which an inner ring | wheel is formed is shown, (a) is a front view of a 3rd modification, (b) is sectional drawing of a 3rd modification. It is a longitudinal cross-sectional view of the fixed type constant velocity universal joint which shows another embodiment of this invention. It is a longitudinal cross-sectional view of the conventional fixed type constant velocity universal joint. It is a cross-sectional view of a conventional fixed type constant velocity universal joint.

Explanation of symbols

21 inner spherical surface 22 track groove 24 outer spherical surface 25 track groove 27 ball 28 cage 28a outer spherical surface 28b inner spherical surface 29 pocket 35 notch

Claims (8)

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 number of the balls is six, the ratio of the pitch circle diameter of the balls to the diameter of the balls is 3.0 or more and 3.3 or less, and the ratio of the outer diameter of the outer member to the diameter of the balls 4.6 or more and 4.8 or less, and 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 opposite in the axial direction by an equal distance from the joint center. In addition to offsetting, the center of curvature of the outer spherical surface of the cage and the center of curvature of the inner spherical surface of the cage are offset in the axial direction by an equal distance from the joint center to offset the center of curvature of the track groove of the outer member. When the offset amount of the center of curvature of the track groove of the inner member and the groove is k, and the offset amount of the center of curvature of the outer spherical surface of the cage and the offset amount of the center of curvature of the inner spherical surface of the cage are k2, −k2) /k≦0.3 A fixed type constant velocity universal joint characterized by increasing the offset amount of the cage . The fixed type constant velocity universal joint according to claim 1, wherein the track grooves of the inner member and the track grooves of the outer member are arranged at unequal pitches in the circumferential direction . 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. The fixed type constant velocity universal joint according to claim 2 , wherein one ball is accommodated in the fixed type. 4. The fixing according to claim 3 , wherein 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. Type constant velocity universal joint. It is characterized in that a bulging portion that protrudes inward of the long pocket is provided on at least one of the long sides facing the long pocket, and two ball accommodating portions that are connected to the long pocket through a slit are provided. The fixed type constant velocity universal joint according to claim 4 . The fixed type constant velocity universal joint according to any one of claims 1 to 5 , wherein a cutout portion is provided at a back end portion of at least one track groove of the inner member . The fixed constant velocity universal joint according to any one of claims 1 to 6 , wherein the track groove bottoms of the inner member and the outer member each have an arc portion and a straight portion . The fixed constant velocity universal joint according to any one of claims 1 to 7 , wherein the track groove bottoms of the inner member and the outer member include an arc portion and a tapered portion .

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