JP2010276049A - Fixed constant-velocity universal joint - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fixed constant velocity universal joint which makes it possible to reduce size and weight and also to improve high-angle strength and durability, while also ensuring the strength of an inner ring (inside joint member) and a cage. <P>SOLUTION: This fixed constant velocity universal joint has an outside joint member for forming a track groove 22 on an inner peripheral surface 21, an inside joint member for forming a track groove 25 on an outer peripheral surface 22, a torque transmission ball 27 arranged in a ball track formed in a pair of the track groove 22 of the outside joint member and the track groove 25 of the inside joint member, and the cage 28 for holding the torque transmission ball 27. A female serration 61 fitted to a male serration 66 of an inserting shaft 65 is formed on an inner diameter surface of the inside joint member, and the female serration 61 is omitted on the joint opening side, and a peripheral cutaway part 84 in which a bottom surface 83 is formed as a cylindrical shape larger than a large diameter of the female serration 61, is formed in its omitted part. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a fixed type constant velocity universal joint that is used in a power transmission system of automobiles and various industrial machines and transmits rotational torque while allowing operating angular displacement between two axes of a driving side and a driven side.

  In automobiles and similar vehicles, rotational power can be transmitted at a constant speed even when there is angular displacement or axial displacement between the two axes in the power transmission path that transmits the driving force from the engine to the wheels. Possible constant velocity universal joints are arranged. The constant velocity universal joint includes a fixed constant velocity universal joint that does not perform plunging motion (axial displacement) and a sliding constant velocity universal joint that performs plunging motion. As a fixed type constant velocity universal joint, a bar field type (BJ) and an undercut free type (UJ) are widely known.

  For example, a UJ type fixed type constant velocity universal joint is an outer joint 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 as shown in FIGS. An outer ring 3, an inner ring 6 as an inner joint member in which a plurality of track grooves 5 paired with the track groove 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.

  Further, the track groove 2 of the outer ring 3 has an arcuate portion 2a on the back side and a straight portion 2b on the opening side. As for the track groove 5 of the inner ring | wheel 6, the back side is made into the linear part 5a, and the opening side is made into the circular arc part 5b. 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 with respect to the joint center O by an equal distance F, F in the axial direction.

In recent years, in order to reduce the size, there are some which have eight balls as shown in FIG. In this case, the cage wall thickness at the cage pocket center position is T _CAGE , the pitch circle radius of the ball when the operating angle is 0 ° is PCR _BALL , and the ratio T _{CAGE /} PCR _BALL is 0.11. About 0.19.

Further, in the conventional UJ type constant velocity universal joint, as shown in FIG. 29, the center of curvature O1, O2 of each of the track grooves 2, 5 of the inner and outer rings 3, 6 and the torque transmitting ball are provided in order to reduce the size and weight. a straight line connecting the seven centers Q of the offset angle theta _tRACK of the track grooves linearly and forms connecting the center Q and the joint center O of the torque transmission balls 7, is used to set the range of 4 ° ≦ θ _tRACK ≦ 6 ° is there.

In such a case, the center of curvature O10 of the inner spherical surface 1 of the outer ring 3 (the center of curvature of the outer spherical surface 8a of the cage 8) and the center of curvature O20 of the outer spherical surface 4 of the inner ring 6 (the center of curvature of the inner spherical surface 8b of the cage 8) are also obtained. These are offset by an equal distance in the axial direction across the joint center O. Then, the offset of the cage 8 formed by a straight line connecting the curvature centers O10, O20 of the inner and outer spherical surfaces 8a, 8b of the cage 8 and the center Q of the torque transmission ball 7 and a straight line connecting the center Q of the torque transmission ball 7 and the joint center O. The angle θ _CAGE is set in a range of 0 ° <θ _CAGE <1 °. Thus, the cage 8, since the offset angle theta _CAGE is set very small, is formed into a substantially uniform thickness.

In recent years, attempts have been made to further reduce the thickness of the cage 8 in order to further reduce the size and weight of the fixed type constant velocity universal joint. In the constant velocity universal joint shown in FIG. 28, if the T _CAGE / PCR _BALL is kept at 0.11 to 0.19 and further downsizing, that is, if the pitch circle radius is reduced, the thickness of the cage 8 is reduced. Inevitably thin. If it becomes thin like this, the rigidity of the column part between the pockets 9 and the side frames of the pockets 9 (window frames facing in the axial direction) decreases. That is, when the joint rotates with a high operating angle, a large load is applied to the end of the cage 8 on the joint opening side, so the strength of that portion must be ensured. However, it is difficult to ensure the strength as a constant velocity universal joint at a high operating angle.

  In the joint configuration shown in FIG. 29, if the cage 8 is set to a small thickness, the cage 8 is uniformly thinly formed, so that the strength of the end portion on the joint opening side of the cage 8 is sufficiently ensured. It was difficult. Further, the reduction in strength of the end portion on the joint opening side due to the reduction in size and weight of the cage 8 is conspicuously observed in a small-sized fixed type constant velocity universal joint applied particularly to small cars and light cars.

  Therefore, as described in Patent Document 1, a six-ball type has been proposed as a new type of fixed type constant velocity universal joint that is compact.

  Incidentally, as shown in FIGS. 30 to 32, a female serration (female spline) 11 is formed on the inner surface of the inner ring 6, and a male serration (male spline) 12 formed on the shaft 13 is fitted into the female serration 11. Match. As a result, the shaft 13 and the inner ring 6 are connected so that torque can be transmitted.

  Further, as shown in FIG. 30, the male spline 12 includes a type in which the valley 12a is directly removed from the outer peripheral surface of the shaft 13 (cut-off type), and a valley 12a of the male spline 12 as shown in FIG. There is a type (round-up type) in which the diameter of the end is smoothly expanded (Patent Document 2). Here, the term “end side” refers to the opposite side when the shaft end face that is first fitted to the inner ring 6 is the start end side when the shaft 13 is inserted into the inner ring 6.

  In FIG. 30, the retaining means W for the shaft 13 is provided only at one place. That is, the retaining means W includes a circumferential groove 15 formed in the male serration 12, a circumferential groove 14 provided in the female serration 11 of the inner ring 6, and a retaining ring that engages with the circumferential grooves 14 and 15. 16.

  In FIG. 31, a retaining means W and a positioning means W1 are provided. The retaining means W in this case is engaged with the notch 17 provided at the starting end of the female serration 11 of the inner ring 6, the circumferential groove 15 formed in the male serration 12, and the notch 17 and the circumferential groove 15. Retaining ring 16. The positioning means W <b> 1 includes an end surface 18 provided on the terminal end side of the inner ring 6 and a contact end surface 19 provided on the outer diameter surface of the shaft 13.

  In FIG. 32, the male spline 12 is a cut-off type similar to that of FIG. Similarly to FIG. 31, the retaining means W includes a notch 17 of the female serration 11, a circumferential groove 15 formed in the male serration 12, and a retaining ring 16 that engages the notch 17 and the circumferential groove 15. Prepare. However, the positioning means W1 is constituted by a stopper 20 attached to the shaft 13. That is, the stopper 20 comes into contact with the end surface 6 a of the inner ring 6.

JP 2000-263163 A JP 2000-97244 A

  By adopting the structure as described in Patent Document 1, the constant velocity universal joint can be made compact. However, a large ball is placed on a small pitch circle diameter (PCD), and the strength balance of internal parts (an assembly consisting of an inner joint member, a ball, a cage, etc.) is different from conventional constant velocity universal joints. Become. That is, when the same shaft as the conventional one is applied, the thickness of the inner ring 6 (particularly, the joint opening side) is reduced by forming the female serration 11. For this reason, the strength of the inner ring 6 is inferior in balance as compared with the outer ring 3 and the cage 8 which are other parts.

  Further, when the male spline is a cut-off type, as described in Patent Document 2, the static strength and fatigue strength are inferior. For this reason, considering the static strength and fatigue strength, a round-up type as shown in FIG. 31 is preferable.

  However, even when the round-up type is used, when the inner ring 6 is formed by forging, a fiber flow is formed along the track groove 5 as shown in FIG. This fiber flow is cut to the female spline 11 side. For this reason, even in the round-up type, in the static torsional strength and fatigue strength tests, the cut portion of the fiber flow becomes a fatigue starting point and the like, resulting in a decrease in strength. Further, in order to increase the torque transmission area, the female serration (female spline) is formed relatively to the inner ring opening side (spline end side). The fact that the female serration is formed up to the end of the spline is also a factor that causes a decrease in strength.

  Therefore, in view of such circumstances, the present invention can reduce the size and weight while ensuring the strength of the inner ring (inner joint member) and the cage, and can improve the high angle strength and durability. It is intended to provide a fixed type constant velocity universal joint.

  The fixed type constant velocity universal joint of the present invention includes an outer joint member in which a plurality of track grooves extending in the axial direction are formed on the inner spherical surface, and an inner joint member in which a plurality of track grooves extending in the axial direction are formed on the outer spherical surface; A plurality of torque transmitting balls disposed on a ball track formed by a pair of a track groove of the outer joint member and a track groove of the inner joint member, an inner spherical surface of the outer joint member, and an outer surface of the inner joint member In a fixed type constant velocity universal joint that is interposed between a spherical surface and includes a cage that holds the torque transmission ball, a female serration that fits with a male serration of a shaft to be inserted is provided on an inner diameter surface of the inner joint member. The female serration is omitted at the joint opening side, and a circumferential notch in which the bottom surface has a cylindrical shape larger than the large diameter of the female serration is formed in the omitted portion. It is obtained by forming a.

  According to the fixed type constant velocity universal joint of the present invention, the female serration is omitted on the joint opening side, and the circumferential notch is formed in the omitted portion, so that the serration in the joint opening side cutting portion of the fiber flow can be eliminated. it can. For this reason, stress relaxation on the joint opening side of the inner joint member can be achieved.

  Preferably, the shaft positioning means is provided on the joint opening side of the inner diameter surface of the inner joint member, and the shaft retaining means is provided on the inner side of the inner diameter surface of the inner joint member. A shaft retaining means may be provided on the joint opening side of the inner diameter surface of the inner joint member.

The number of the torque transmission balls is six, and the ratio r1 (= PCD _BALL / D _BALL ) between the pitch circle diameter (PCD _BALL ) of the torque transmission balls and the diameter (D _BALL ) of the torque transmission balls, The range can be set to 3.0 ≦ r1 ≦ 3.3. Thereby, the strength and durability as a constant velocity universal joint can be ensured.

  If the ratio of the pitch circle diameter to the ball diameter is less than 3.0, if the ball diameter is large, the inner joint member becomes too thin, which raises concerns about strength. When the diameter is small, the surface pressure between the inner joint member (inner ring) / outer joint member (outer ring) and the ball increases, which raises concerns about durability. On the contrary, if the ball diameter exceeds 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, the outer diameter of the outer joint member is small. It becomes large and cannot be made compact.

The ratio r2 (= D _OUTER / D _BALL ) between the outer diameter (D _OUTER ) of the outer joint member and the diameter (D _BALL ) of the torque transmission ball is set in the range of 4.6 ≦ r 2 ≦ 4.8. be able to. If the ratio between the outer diameter of the outer joint member and the diameter of the ball is less than 4.6, the outer joint member becomes too thin when the ball diameter is large. When the outer diameter of the joint member is small, the surface pressure between the inner joint member / outer joint member and the ball is increased, which raises concerns about durability. Conversely, if it exceeds 4.8, when the ball diameter is small, the load capacity of the ball becomes small, which raises concerns about durability, and when the outer diameter of the outer joint member is large, downsizing cannot be achieved.

Cage offset angle formed by a straight line connecting the center of curvature of the inner and outer spherical surfaces of the cage and the center of the torque transmission ball and a straight line connecting the center of the torque transmission ball and the center of the joint when the joint operating angle is 0 ° the theta _CAGE, can be set in the range of _{2.7 ° ≦ θ CAGE ≦ 5.7 °} .

By setting the cage offset angle θ _CAGE to be larger than the conventional cage offset angle (0 ° <θ _CAGE <1 °), the thickness of the end of the cage on the joint opening side is larger than that of other portions. Molded thick. When the offset angle of the cage is less than 2.7 °, the end portion on the joint opening side of the cage becomes thin, and sufficient strength cannot be secured. If the angle exceeds 5.7 °, the thickness of the end of the cage on the back side becomes extremely thin. Heat treatment is generally performed in the cage manufacturing process. However, if the cage thickness becomes extremely thin, the uncured layer due to the heat treatment decreases in the thin portion, and the toughness decreases and sufficient strength cannot be secured. . Moreover, if the thickness difference between the end portion on the joint opening side of the cage and the end portion on the back side of the joint is large, the workability may be deteriorated.

The cage wall thickness at the cage pocket center position is T _CAGE, and the pitch circle radius of the ball when the operating angle is 0 ° is PCR _BALL, and this ratio T _CAGE / PCR _BALL is 0.20 or more and 0.0. It is good also as 23 or less. By satisfying 0.20 ≦ tCAGE / PCRBALL ≦ 0.23, it is possible to reduce the size and improve the cage strength, and to prevent the balls 27 from climbing onto the edge of the track groove.

If t _CAGE / PCR _BALL is less than 0.20, the outer diameter will increase, making it difficult to reduce the size of the cage, reducing the wall thickness of the cage, and securing the required joint strength at large angles. Become. On the other hand, when t _CAGE / PCR _BALL exceeds 0.23, the inner ring (inner joint member) in the inner diameter serration part (shaft fitting part) becomes thinner, and the required joint at a large angle (at a high operating angle) Ensuring strength is difficult, and the spherical surfaces of the inner ring and the outer ring are reduced, so that the allowable torque level is lowered. As a result, it becomes easy for the ball to ride on the edge portions of the track grooves of the inner ring and the outer ring, and the durability may be significantly reduced.

  The center of curvature of the track groove of the outer joint member and the center of curvature of the track groove of the inner joint 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 sphere is preferably offset in the axial direction by an equal distance from the joint center, and the offset amount of the cage is preferably 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.

  By the way, when incorporating the inner joint member into the cage, one of the outer spherical surfaces disposed between the track grooves of the inner joint member is inserted into the cage pocket, and the inner joint member is accommodated in the cage. become. For this reason, if the track grooves of the inner and outer joint members are arranged at unequal pitches in the circumferential direction and the pillars of the cage arranged in a narrow pitch are removed, the pillars are removed by The outer spherical surface of the inner joint member can be dropped into the removal portion.

  Moreover, when assembling a constant velocity universal joint, a cage is incorporated in an outer joint member. For this reason, among the pitches between the track grooves of the inner and outer joint members, the phase of two pitches is set to 60 ° or less, and the phase of the remaining four pitches is set to 60 ° or more, so Can be improved. That is, when the cage is incorporated into the outer joint member, the cage pocket is incorporated so as to oppose the inner spherical surface of the outer joint member disposed within a small phase pitch. At this time, the circumferential length of the opening side end portion of the inner spherical surface arranged in a small pitch is set to be smaller than the width of the opposing pocket of the cage, and the inner spherical surface becomes the outer circumferential surface of the cage. The cage can be easily incorporated into the outer joint member without interference.

  In the fixed type constant velocity universal joint of the present invention, stress relaxation can be achieved at the joint opening of the inner joint member, and the strength of the inner joint member can be improved. For this reason, the shaft of the same introduction as the past can be applied, and it can be shared with the conventional product, and the cost can be reduced. In addition, by setting the range to 3.0 ≦ r1 ≦ 3.3, the strength and durability as a constant velocity universal joint can be ensured, and a highly accurate constant velocity universal joint can be provided.

  Further, when the ratio between the outer diameter of the outer joint 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. By setting the cage offset angle to 2.7 ° or more and 5.7 ° or less, the thickness of the end of the cage on the joint opening side can be made thicker than other parts. Even if the cage is thinly formed in order to reduce the size and weight, the end portion on the joint opening side of the cage can ensure the strength to withstand the load applied when the joint is rotated at a high operating angle.

By satisfying 0.20 ≦ t _CAGE / PCR _BALL ≦ 0.23, it is possible to reduce the size and improve the cage strength, and to prevent the ball from climbing onto the edge of the track groove. That is, according to the present invention, it is possible to reduce the size (miniaturization), to ensure the strength of the cage even if the size is reduced, and to prevent damage to the cage when a high-angle torsional torque load is applied. Improvements can be made. For this reason, the joint strength durability can be ensured to be equal to or better than the conventional product (8-ball fixed joint) with a more compact form.

  By increasing the cage offset amount to be approximately the same as the track groove offset amount, it is possible to prevent the depth of the track groove on the inner side of the joint from being reduced, and to increase the cage thickness (diameter thickness) on the opening side. Can be bigger. 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, it prevents the torsional torque load capacity from decreasing at high angles, improves (improves) high-angle durability life, and improves (improves) damage strength due to plastic deformation of the track grooves of the inner joint member and outer joint member at high angles. Can be planned.

  If the track groove of the inner joint member and the track groove of the outer joint member are arranged at unequal pitches in the circumferential direction, and the cage pillars with a narrow pitch are removed, the cage can be easily incorporated into the outer joint member (outer ring). In addition, a long window is inevitably formed, and the long window width becomes larger than the inner ring width, so that the inner ring cage can be easily assembled. In addition, by setting the phase of the two pitches to 60 ° or less and the phase of the remaining four pitches to 60 ° or more in the track groove of the outer joint member, the cage can be assembled without interference.

It is a longitudinal section of a fixed type constant velocity universal joint which shows a 1st embodiment of the present invention. It is a longitudinal cross-sectional view of the said fixed type constant velocity universal joint. It is a cross-sectional view of the fixed type constant velocity universal joint. It is a principal part longitudinal cross-sectional view of the said fixed type constant velocity universal joint. It is sectional drawing of the inner ring | wheel of the said fixed type constant velocity universal joint. It is a cross-sectional view of the fixed type constant velocity universal joint which shows the 2nd 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. 6, and a cage. It is a side view which shows the relationship between the inner ring | wheel of the fixed type constant velocity universal joint shown in FIG. 6, and a cage. FIG. 7 is a side view showing an assembled state of the inner ring into the cage of the fixed type constant velocity universal joint shown in FIG. 6. The cage of a fixed type constant velocity universal joint is shown, (a) is a side view of the cage of FIG. 6, (b) is a side view showing a first modification of the cage, and (c) is a side view of the cage. It is a side view which shows a 2nd modification, (d) is a side view which shows the 3rd modification of a cage. The cage of a fixed type constant velocity universal joint is shown, (a) is a side view showing a fourth modification of the cage, and (b) is a side view showing a fifth modification of the cage. 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. 15 is a cross-sectional view showing a method of incorporating the cage into the cage using the inner ring shown in FIG. 14. It is explanatory drawing of the clearance gap formed at the time of incorporating in a cage. It is a perspective view which shows the other modification of an inner ring | wheel. FIG. 20 is a front view of the inner ring shown in FIG. 19. It is sectional drawing of the inner ring | wheel shown in the said FIG. The notch part formed in an inner ring | wheel 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 formed in an inner ring | wheel 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 the 3rd Embodiment of this invention. It is a longitudinal cross-sectional view of the fixed type constant velocity universal joint which shows the 4th Embodiment of this invention. It is a longitudinal cross-sectional view of the fixed type constant velocity universal joint which shows the 5th 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. It is a longitudinal cross-sectional view of the conventional fixed type constant velocity universal joint. It is a longitudinal cross-sectional view which shows the relationship between the inner ring | wheel of the conventional fixed type constant velocity universal joint, and a shaft. It is a longitudinal cross-sectional view which shows the relationship between the other inner ring | wheel and the shaft of the conventional fixed type constant velocity universal joint. It is a longitudinal cross-sectional view which shows the relationship between another inner ring | wheel of the conventional fixed type constant velocity universal joint, and a shaft. It is explanatory drawing of the fiber flow formed in an inner ring.

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

  As shown in FIGS. 1 and 2, the fixed type constant velocity universal joint includes an outer ring 23 as an outer joint member in which a plurality (six) of track grooves 22 are formed on the inner spherical surface 21 along the axial direction, An inner ring 26 as an inner joint member in which a plurality of (six) track grooves 25 that are paired with the track grooves 22 of the outer ring 23 are formed in the spherical surface 24 along the axial direction, and the track grooves 22 and the inner rings 26 of the outer ring 23 are formed. A plurality of (six) balls 27 that transmit torque between the track grooves 25 and a pocket that holds the balls 27 interposed between 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. In this case, as shown in FIG. 3, 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.

  A female serration (female spline) 61 that is a torque transmission part is formed on the inner diameter surface of the hole 60 of the inner ring 26. That is, as shown in FIG. 5, the shaft 65 is fitted into the hole 60 of the inner ring 26, and the male serration 66 provided on the shaft 65 is fitted to the female serration 61 of the inner ring 26. As a result, torque between the shaft 65 and the inner ring 26 is transmitted. A circumferential groove 67 is formed at the end of the male serration 66, and a retaining ring 68 is attached to the circumferential groove 67. As a result, the retaining ring 68 is engaged with the notch 69 at the end of the inner diameter surface of the hole 60 of the inner ring 26 (the end on the joint back side), thereby constituting the retaining means W for the shaft 65. That is, the retaining means W is provided on the inner side of the joint of the inner ring 26 and is engaged with the circumferential groove 67 of the shaft 65, the notch 69 of the inner ring 26, and the circumferential groove 67 and the notch 69. 68.

  By the way, this male serration (male spline) 66 is a type (round-up type) in which the end side of the valley 66a of the male spline 66 is smoothly expanded. That is, the rising portion 80 is provided on the end side of the valley portion 66 a of the male spline 66, and the downward inclined portion 81 is provided on the serration end side of the peak portion 66 b of the male spline 66. Here, the term “end side” refers to the opposite side when the shaft end face that is first fitted to the inner ring 26 when the shaft 65 is inserted into the inner ring 26 is defined as the start end side.

  The female serration 66 is omitted on the joint opening side (terminal side), and a circumferential notch (large diameter portion) 84 having a bottom surface 83 having a cylindrical shape larger than the large diameter of the female serration 66 is formed in the omitted portion. Yes. That is, when the maximum outer diameter dimension of the female serration 66 is D1 and the inner diameter dimension of the circumferential notch 84 is D2, D1 <D2.

  By providing the circumferential cutout (large diameter portion) 84 in this way, serrations at the joint opening side cutting portion of the fiber flow can be eliminated. For this reason, stress relaxation at the joint opening side of the inner ring 26 can be achieved.

  Further, the shaft 65 is provided with a taper portion 87 whose diameter increases from the serration end of the male serration 66 toward the joint opening, and this taper portion 87 contacts the taper portion 85 of the inner ring 26. The taper portion 85 of the inner ring 26 and the taper portion 87 of the shaft 65 constitute a positioning means W1.

  That is, if the male serration 66 at the end of the shaft 65 is fitted into the inner ring 26, it can be fitted until the tapered portion 87 of the shaft 65 contacts the tapered portion 85 of the inner ring 26. In this contacted state, the retaining ring 68 is engaged with the circumferential groove 67 and the notch 69.

  Therefore, as shown in FIG. 5, the retaining ring 68 engages with the circumferential groove 67 and the notch 69, and the taper 85 of the inner ring 26 and the taper 87 of the shaft 65 are in contact with each other. 65 is restricted from moving in the axial direction relative to the inner ring 26. That is, when an external force in the direction in which the shaft 65 moves in the direction of the arrow E1 acts on the inner ring 26, the taper portion 87 of the shaft 65 is in contact with the taper portion 85 of the inner ring 26. Is regulated. Further, when an external force in the direction in which the shaft 65 moves in the direction of the arrow E2 is applied to the inner ring 26, the retaining ring 68 is engaged with the notch 69, so that the movement in the direction of the arrow E2 is restricted.

  By the way, the track groove 22 of the outer ring 23 and the track groove 25 of the inner ring 26 can be formed by plastic working, grinding or the like.

  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.

As shown in FIG. 3, the cage wall thickness at the pocket center position of the cage 28 is t _CAGE , the pitch circle radius of the ball 27 when the operating angle is 0 ° is PCR _BALL, and this ratio t _CAGE / PCR _{BALL is set} to 0.20 or more and 0.23 or less.

Further, as shown in FIG. 3, the pitch circle diameter _{PCD BALL} and the ratio r1 between the diameter _{D BALL} of the ball 27 of the ball 27, and 3.0 or more 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 is set to 4.6 or more and 4.8 or less. That is, 4.6 ≦ r2 ≦ 4.8.

Here, the pitch circle radius PCR _BALL is the radius of the locus of the circle drawn by the ball center, and the pitch circle diameter PCD _BALL is the diameter of the locus of the circle drawn by the ball center. That is, the pitch circle diameter PCD _BALL is the length PCR of the line segment connecting the center of curvature O1 of the track groove 22 of the outer ring 23 or the center of curvature O2 of the track groove 25 of the inner ring 26 and the center Q of the torque transmitting ball 7. (PCD _BALL = PCR × 2).

As shown in FIG. 4, when the operating angle is 0 °, a straight line L3 connecting the center of curvature O3 of the outer spherical surface 28a of the cage 28 and the ball center Q, and a straight line connecting the joint center O and the ball center Q. An angle θ3 formed by L, and an angle θ4 formed by a straight line L4 connecting the center of curvature O4 of the inner spherical surface 28b of the cage 28 and the ball center Q, and a straight line L connecting the joint center O and the ball center Q, respectively. It is set to 2.7 ° or more and 5.7 ° or less. The angles θ3 and θ4 are called cage offset angles (θ _CAGE ). The operating angle of 0 ° is a state where the axis of the outer ring 23 and the axis of the inner ring coincide. That is, 2.7 ° ≦ θ _CAGE ≦ 5.7 ° is set.

Thus, the offset angle theta _CAGE of the cage by setting larger than the offset angle of a conventional cage _{(0 ° <θ CAGE <1} °) shown in FIG. 27, the joint opening side of the cage 28 of the end portion The wall thickness is formed thicker than other parts. As a result, even if the cage 28 is thinly formed in order to reduce the size and weight of the joint, the end of the cage 28 on the joint opening side has sufficient strength to withstand the load applied when the joint is rotated at a high operating angle. be able to.

If the offset angle θ _{CAGE of the} cage is θ _CAGE <2.7 °, the end portion on the joint opening side of the cage 28 becomes thin, and sufficient strength cannot be secured. Further, when 5.7 ° <θ _CAGE , the thickness of the end portion of the cage 28 on the joint back side becomes extremely thin. Heat treatment is generally performed in the cage manufacturing process. However, when the thickness of the cage 28 becomes extremely thin, the uncured layer due to the heat treatment is reduced in the thin portion, and the toughness is lowered and sufficient strength can be secured. Disappear. Further, if the thickness difference between the end portion on the joint opening side of the cage 28 and the end portion on the back side of the joint is large, the workability may be deteriorated.

In addition, when the operating angle is 0 °, an angle formed by a straight line L1 connecting the curvature center O1 of the track groove 22 of the outer ring 23 and the ball center Q and a straight line L connecting the joint center O and the ball center Q. θ1 and an angle θ2 formed by a straight line L2 connecting the center of curvature O2 of the track groove 25 of the inner ring 26 and the ball center Q and a straight line L connecting the joint center O and the ball center Q are respectively represented by the offset angle (θ _CAGE ). Note that the angles θ1 and θ2 are referred to as track offset angles (θ _TRACK ). In this embodiment, the center of curvature O1 of the track groove 22 of the outer ring 23 is disposed closer to the anti-joint center side than the center of curvature O3 of the outer spherical surface 28a of the cage 28, and the center of curvature O2 of the track groove 25 of the inner ring 26 is It arrange | positions rather than the curvature center O4 of 28 inner spherical surfaces 28b in the anti-joint center side. For this reason, in this embodiment, the track offset angle (θ _TRACK ) is set slightly larger than the cage offset angle (θ _CAGE ).

  In the present invention, since the number of balls is six, a relatively large ball can be used. For this reason, 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. Since the thickness of the column portion between the pockets of the cage 28 can also be increased, the strength at a high operating angle can be ensured.

  The female serration 66 is omitted on the joint opening side, and a circumferential cutout 84 is formed in the omitted portion. Thereby, serration in the joint opening side cutting part of the fiber flow can be eliminated. For this reason, stress relaxation at the joint opening side fiber flow cutting part of the inner ring 26 can be achieved, and the strength of the inner ring 26 can be improved. Therefore, the shaft having the same introduction as the conventional one can be applied, and it can be shared with the conventional product, and the cost can be reduced.

  The fixed type constant velocity universal joint having no circumferential cutout 84 shown in FIG. 1 and the same type and the same size as the fixed type constant velocity universal joint shown in FIG. 1 and having no circumferential cutout 84. With respect to the conventional fixed type constant velocity universal joint, the stress value of the inner diameter of the opening-side thin portion of the inner ring was examined by FEM analysis (finite element method) at an operating angle of 46 °. As a result, the fixed type constant velocity universal joint that does not have the circumferential notch 84 is reduced by about 70% compared to the fixed type constant velocity universal joint that does not have the circumferential notch 84.

By the way, when t _CAGE / PCR _BALL is less than 0.20, the outer diameter becomes large, it becomes difficult to make compact, the thickness of the cage becomes thin, and the necessary joint strength at a large angle can be secured. It becomes difficult. On the other hand, when t _CAGE / PCR _BALL exceeds 0.23, the inner ring (inner joint member) in the inner diameter serration part (shaft fitting part) becomes thinner, and the required joint at a large angle (at a high operating angle) As a result, it becomes difficult to secure the strength, and the spherical surfaces of the inner ring 26 and the outer ring 23 become smaller, so that the allowable torque level is lowered. As a result, the ball 27 can easily ride on the edge portions of the track grooves 25 and 22 of the inner ring 26 and the outer ring 23, and the durability may be significantly reduced.

For this reason, by satisfying 0.20 ≦ t _CAGE / PCR _BALL ≦ 0.23, it is possible to reduce the size and improve the cage strength, and to prevent the ball 27 from climbing onto the edge of the track groove. . That is, according to the present invention, it is possible to reduce the size (miniaturization), to secure the strength of the cage 28 even if the size is reduced, and to prevent the cage from being damaged when a high-angle torsional torque load is applied. Can be improved. For this reason, the joint strength durability can be ensured to be equal to or higher than that of the conventional product (8-ball fixed joint) with a more compact form.

In addition, by setting the ratio of the pitch circle diameter PCD _BALL of the ball 27 to the diameter of the ball 27 to be 3.0 or more and 3.3 or less, the strength and durability as a constant velocity universal joint can be secured, A highly accurate constant velocity universal joint can be provided. When the ratio between the pitch circle diameter PCD _BALL and the diameter of the ball 27 is r1, if r1 <3.0, if the diameter of the ball 27 is large, the inner ring 26 is too thin, When the pitch circle diameter of the ball 27 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. 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. Thereby, further strength and durability can be secured. 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 27 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.

  By setting the offset angles θ3 and θ4 of the cage 28 to be not less than 2.7 ° and not more than 5.7 °, the thickness of the end portion on the joint opening side of the cage 28 is made thicker than other portions. Even if the cage 28 is thinly formed in order to reduce the size and weight of the joint, the joint opening side end of the cage 28 has sufficient strength to withstand the load applied when the joint is rotated at a high operating angle. be able to. By setting the offset angles θ3 and θ4 of the cage 28 to be not less than 2.7 ° and not more than 5.7 °, the thickness of the end portion on the joint opening side of the cage 28 is formed thicker than other portions. . If the offset angles θ3 and θ4 of the cage 28 are less than 2.7 °, the end portion on the joint opening side of the cage 28 becomes thin, and sufficient strength cannot be ensured. If the angle exceeds 5.7 °, the thickness of the end of the cage 28 on the back side of the joint becomes extremely thin. Heat treatment is generally performed in the cage manufacturing process. However, when the thickness of the cage 28 becomes extremely thin, an uncured layer due to the heat treatment is reduced in the thin portion, and the toughness is lowered and sufficient strength can be secured. Disappear. Further, if the thickness difference between the end portion on the joint opening side of the cage 28 and the end portion on the back side of the joint is large, the workability may be deteriorated.

  Further, in the present invention, the offset amount k of the cage 28 is made substantially the same as the offset amounts of the track grooves 22 and 25. For this reason, it is possible to prevent the depth of the track groove on the back side of the joint from becoming shallow, and to increase the thickness (diameter thickness) of the cage 28 on the opening side. 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 25 and 22 of the inner ring 26 and outer ring 23 at high angles. Can be achieved.

  FIG. 6 shows another embodiment, and the cage 28 in this case has 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 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. 7, 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. That is, the track grooves 25 and 22 of the inner ring 26 and the outer ring 23 are arranged at unequal pitches in the circumferential direction, and the smallest pitch among the plurality of inner spherical surfaces arranged between the track grooves of the outer ring 23. The circumferential length (the shoulder width dimension between track grooves) f of the opening side end portion of the inner spherical surface disposed inside is set smaller than the pocket width g of the cage 28. Furthermore, as shown in FIG. 8, the axial length i of the inner ring 26 is shorter than the circumferential interval h of the long pocket 30.

  By the way, as shown in FIGS. 7 and 8, the long pocket 30 has a bulging portion 36 that protrudes inwardly of the long pocket at the center in the longitudinal direction of the long sides 35a, 35b facing each other. 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 bulging portion 36 has a trapezoidal shape in which the side is an arcuate 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. 8, 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. 8 and 9, when the inner ring 26 is incorporated 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 joint member of the cage 28 and the outer spherical surface 24 of the inner joint member, so that deterioration of the operability of the joint can be prevented, and the operability of the joint can be 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.

  As described above, in the fixed type constant velocity universal joint shown in FIG. 6 and the like, the track grooves 25 and 22 of the inner ring 26 and the outer ring 23 are arranged at unequal pitches in the circumferential direction, and between the track grooves of the outer ring 23. Of the plurality of arranged inner spherical surfaces, the circumferential length f of the opening side end portion of the inner spherical surface arranged within the minimum pitch is set smaller than the width g of the pocket 29 of the cage 28.

  With this configuration, when the cage 28 is incorporated into the outer ring 23, the pockets 29 of the cage 28 are incorporated so as to face the inner spherical surface disposed within the minimum pitch of the outer ring 23. In this case, since the circumferential length of the opening side end portion of the inner spherical surface disposed within the minimum pitch is set smaller than the width of the pocket 29 of the opposing cage 28, the inner spherical surface is the outer periphery of the cage 28. The cage 28 can be easily incorporated into the outer ring 23 without interfering with the surface.

  Further, among the pitches between the track grooves of the inner ring 26 and the outer ring 23, the phase of two pitches positioned symmetrically with respect to the joint center is set to be smaller than 60 °, and the phase of the remaining four pitches is set to 60. The circumferential length f of the opening side end portion of the inner spherical surface of the outer ring 23 disposed within the pitch of the phase smaller than 60 ° is set smaller than the width of the pocket 29 of the cage 28. Will be.

  In such a case, the cage 28 can be easily incorporated into the outer ring 23. Further, since the inner spherical surface (opening side end portion) having a circumferential length smaller than the width of the pocket 29 is arranged symmetrically with respect to the joint center, it becomes easier to incorporate.

  In the long pocket 30 of the above embodiment, as shown in FIG. 10 (a), the bulging portions 36, 36 have a so-called trapezoidal shape, but FIG. 10 (b), FIG. 10 (c), FIG. ). That is, the bulging portions 36 and 36 in FIG. 10B 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 bulging portions 36 and 36 in FIG. 10D are rectangular.

  Even the cage 28 having the long pocket 30 shaped as shown in FIGS. 10 (b), 10 (c), and 10 (d) has the same effects as the cage 28 of FIG. 10 (a). .

  Moreover, as shown in FIG. 11, you may abbreviate | omit either one of a pair of bulging parts 36 and 36. As shown in FIG. In FIG. 11A, the bulging portion 36 is provided only on the long side 35a side on the joint opening side, and in FIG. 11B, the bulging portion 36 is provided only on the long side 35b side on the joint opening side.

  In the case shown in FIG. 11A, the 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 this case, the interference between the back 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 can be delayed or eliminated.

  Moreover, as shown in FIG. 12 and FIG. 13, 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.

  By the way, when the cage 28 having the long pockets 30 is manufactured, in the existing cage in which the pockets are formed at a pitch of 60 ° along the circumferential direction, the pillar portion between the pockets adjacent in the circumferential direction may be removed. That is, the pair of pillars in the opposite direction with respect to the cage center may be removed. As this removal method, it can carry out by press work, milling, etc., for example. In the case of the cage 28 shown in FIGS. 10 and 11, a part of the column part to be removed is left, but in the cage 28 shown in FIGS. 12 and 13, the entire (all) part of the column part to be removed is removed. Yes. When the long pocket 30 is formed, the pillar portion disposed in the large pitch may be removed. However, in order to secure the strength of the cage 28, the pillar portion disposed in the small pitch is not provided. It is desirable to remove and leave the thick pillars arranged in the large pitch.

  As described above, the cage 28 can be easily formed by removing the pillar portion in the existing cage, and the removal of the pillar portion can be performed by milling even if it is press working. It may be, and can be stably formed by these various plastic workings.

  If a long pocket 30 capable of holding the two torque transmitting balls 27 is formed in the cage 28 and the circumferential length h of the long pocket 30 is set larger than the width i of the inner ring 26, the inner ring 26 As a result, it is possible to improve the assemblability when the is assembled into the cage 28.

  As shown in FIGS. 14-16, you may provide the notch part 45 in the back side edge part (terminal edge part of a coupling back side) of one track groove 25 (25A) of the inner ring | wheel 26. As shown in FIG. 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. In addition, this notch part 45 is comprised from the inclination part. In this case, it may be molding by machining or molding by plastic working.

  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. 17, a part of the outer spherical surface 24 of the inner ring 26 (projection 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 45. 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.

  Therefore, in FIG. 17, 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, so that (A−B) <( AC). 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. Therefore, a larger space can be ensured between the inner diameter of the cage 28 and the inner ring 26, and accordingly, the inner diameter A of the cage 28 can be set smaller. That is, in a state where the track groove 25 of the inner ring 26 in which the notch 45 is formed is straddled over the entrance of the cage 28, the notch 45 approaches or contacts the entrance (inlay) as shown in FIG. is doing. That is, the inner ring 26 having the notch 45 can be further lowered and inserted as compared with a conventional inner ring having no notch 45. Thereby, since the clearance gap S between the upper end surface of the inner ring | wheel 26 and an entrance part can be ensured large, an assembly | attachment becomes easy.

  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. Further, 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. 19 to 21 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. 14 to 16, 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. 19 to 21 has the same effect as the inner ring 26 shown in FIGS. 12 to 14.

  In particular, since the notch 45 is formed at the back end of all the track grooves 25, any protrusion (shoulder) 47 can be inserted into the pocket 30 when the inner ring 26 is assembled into the cage 28. Good. 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. ) And the shape shown in FIG. The notch 45 shown in FIG. 22A has a concave round shape, and the notch 45 shown in FIG. 22B has a convex round shape.

  Even in the cutout 45 shown in FIGS. 22 (a) and 22 (b), the inner ring 26 can be rotated from the cutout 45 when it is assembled, and the rotation radius of the inner ring 26 is reduced. can do. Further, as shown in FIGS. 23A and 23B, the notch 45 may be formed at a part of the track groove end (the bottom in the example).

  Although not shown, the notch 45 is shown in FIGS. 14 to 16, shown in FIGS. 22 (a) and 22 (b), or shown in FIGS. 23 (a) and 23 (b). Other than the above, for example, a step portion or the like may be used. Even the cutout 45 such as the stepped portion exhibits the function as the cutout 45.

  In FIG. 24, the male spline 66 of the shaft 65 is a type (cut-off type) in which the trough portion 66a is directly removed from the outer peripheral surface of the shaft 65. Also in this case, the female serration 61 of the inner ring 26 is omitted on the joint opening side, and a circumferential notch 84 having a bottom surface 83 having a cylindrical shape larger than the large diameter of the female serration is formed in the omitted portion.

  Further, a retaining means W is provided on the back side of the joint. The retaining means W in this case includes a circumferential groove 90 provided in the male spline 66 of the shaft 65, a circumferential groove 91 provided in the female spline 61 of the inner ring 26, and a stopper engaged with the circumferential grooves 90, 91. A ring 92. That is, in the retaining means W, the retaining ring 92 is engaged with the circumferential grooves 90 and 91, so that the shaft 65 slides in the direction of the arrows E1 and E2 in the axial direction with respect to the inner ring 26. It is regulated.

  25, as shown in FIG. 24, the male spline 66 of the shaft 65 is a cut-off type, and the positioning means W1 of the shaft 65 is provided on the joint opening side of the inner ring 26, and the joint of the inner ring 26 is provided. On the back side, a retaining means W for the shaft 65 is provided.

  As with the retaining means W shown in FIG. 5, the retaining means W includes a circumferential groove 67 of the shaft 65, a notch 69 of the inner ring 26, and a retaining ring that engages with the circumferential groove 67 and the notch 69. 68. Further, the positioning means W1 includes a stopper 93 made of a ring body attached to the shaft 65, and this stopper 93 comes into contact with the end surface 93a on the opening side of the inner ring 26.

  That is, when an external force in the direction in which the shaft 65 moves in the direction of the arrow E1 acts on the inner ring 26, the stopper 93 of the shaft 65 is in contact with the end surface 93a on the opening side of the inner ring 26. Movement is restricted. Further, when an external force in the direction in which the shaft 65 moves in the direction of the arrow E2 is applied to the inner ring 26, the retaining ring 68 is engaged with the notch 69, so that the movement in the direction of the arrow E2 is restricted.

  24 and 25, the female serration of the shaft 65 is omitted on the joint opening side, and a circumferential cutout is formed in the omitted portion. Therefore, the joint opening side cutting portion of the fiber flow is formed. Serrations can be eliminated. For this reason, there exists an effect similar to the constant velocity universal joint shown in FIG.

  Next, FIG. 26 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 k is substantially the same as the offset amount k2 of the track grooves 22 and 25.

  Also in the inner ring 26, the female serration 61 is omitted on the joint opening side, and a circumferential notch 84 having a bottom surface 83 having a cylindrical shape larger than the large diameter of the female serration 61 is formed in the omitted portion. 26 is the same as that 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. Omitted.

  For this reason, the fixed type constant velocity universal joint shown in FIG. 26 has the same effects as the fixed type constant velocity universal joint shown in FIG. In FIG. 1, the joint operating angle can be increased by adopting an undercut free type in which the track groove bottoms of the inner ring 26 and the outer ring 23 are provided with arc portions and straight portions. In contrast, as shown in the fixed type constant velocity universal joint shown in FIG. 26, if the track groove bottom has an arc portion and a tapered portion, 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. 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. Further, when the curvature center O1 and the curvature center O3 are shifted, or when the curvature center O2 and the curvature center O4 are shifted, the shift amount can be arbitrarily set, but the offset amount k and the shift amount (k−k2). 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. 27, 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 less than the required strength of the joint.

  The circumferential interval h of the long pockets 30 can be variously set within the 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. 26, a cage 28 having a long pocket 30 as shown in FIGS. 10 to 13 may be used. Moreover, you may use the inner ring | wheel 26 which has the notch part 45 as shown in FIG.14 and FIG.18 for the inner ring | wheel 26. FIG.

  As shown in FIG. 6 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.

21 inner spherical surface 22 track groove 23 outer ring 24 outer spherical surface 25 track groove 26 inner ring 27 torque transmission ball 28 cage 28a outer spherical surface 28b inner spherical surface 29 pocket 33 column 61 female serration 65 shaft 66 male serration 83 bottom surface 84 circumferential notch W Stopping means W1 Positioning means

Claims (10)

An outer joint member having a plurality of track grooves extending in the axial direction on the inner spherical surface, an inner joint member having a plurality of track grooves extending in the axial direction on the outer spherical surface, and the track grooves and the inner surfaces of the outer joint member A plurality of torque transmitting balls disposed on a ball track formed in pairs with a track groove of a joint member; and the torque transmission between the inner spherical surface of the outer joint member and the outer spherical surface of the inner joint member In a fixed constant velocity universal joint with a cage that holds the ball,
A female serration that fits with the male serration of the shaft to be inserted is formed on the inner diameter surface of the inner joint member, the female serration is omitted on the joint opening side, and a bottom surface of the female serration is formed on the omitted portion. A fixed type constant velocity universal joint, characterized in that a circumferential cutout having a cylindrical shape larger than a large diameter is formed.   2. The fixed constant velocity universal joint according to claim 1, wherein a shaft positioning means is provided on the joint opening side of the inner joint member, and a shaft retaining means is provided on the inner joint side of the inner joint member.   2. The fixed type constant velocity universal joint according to claim 1, wherein means for preventing the shaft from coming off is provided on the joint back side of the inner joint member. The number of the torque transmission balls is six, and the ratio r1 (= PCD _BALL / D _BALL ) between the pitch circle diameter (PCD _BALL ) of the torque transmission balls and the diameter (D _BALL ) of the torque transmission balls, The fixed constant velocity universal joint according to claim 1, wherein the fixed constant velocity universal joint is set in a range of 3.0 ≦ r1 ≦ 3.3. The ratio r2 (= D _OUTER / D _BALL ) between the outer diameter (D _OUTER ) of the outer joint member and the diameter (D _BALL ) of the torque transmitting ball was set in the range of 4.6 ≦ r 2 ≦ 4.8. The fixed type constant velocity universal joint according to any one of claims 1 to 4, wherein the fixed type constant velocity universal joint is provided. Cage offset angle formed by a straight line connecting the center of curvature of the inner and outer spherical surfaces of the cage and the center of the torque transmission ball and a straight line connecting the center of the torque transmission ball and the center of the joint when the joint operating angle is 0 ° the _{θ CAGE, 2.7 ° ≦ θ CAGE} ≦ 5.7 ° fixed type constant velocity universal joint according to any one of claims 1 to 5, characterized in that set in the range of. The cage wall thickness at the cage pocket center position is T _CAGE, and the pitch circle radius of the ball when the operating angle is 0 ° is PCR _BALL, and this ratio T _CAGE / PCR _BALL is 0.20 or more and 0.0. The fixed constant velocity universal joint according to any one of claims 1 to 6, wherein the fixed constant velocity universal joint is 23 or less.   The center of curvature of the track groove of the outer joint member and the center of curvature of the track groove of the inner joint 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 sphere is offset in the opposite axial direction by an equal distance from the joint center, and the offset amount of the cage is substantially the same as the offset amount of the track groove. The fixed type constant velocity universal joint according to claim 7.   9. The track grooves of the inner and outer joint members are disposed at unequal pitches in the circumferential direction, and the pillar portions of the cage disposed within the narrow pitch are removed. The fixed type constant velocity universal joint according to item 1.   The phase of two pitches among the pitches between the track grooves of the inner and outer joint members is set to 60 ° or less, and the phases of the remaining four pitches are set to 60 ° or more. 9. A fixed type constant velocity universal joint according to 9.

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