JP5885997B2 - 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, an automotive front drive shaft usually has a sliding constant velocity universal joint on the inboard side (difference side) that has a relatively small maximum operating angle but can be displaced in the axial direction while maintaining the operating angle. On the outboard side (wheel side), since the wheel is steered, a fixed type constant velocity universal joint that can take a large operating angle but is not displaced in the axial direction is incorporated.

  As an example of a fixed type constant velocity universal joint used on the outboard side, a Rzeppa type constant velocity universal joint 101 is shown in FIG. FIG. 19A is a longitudinal sectional view in a state where the operating angle is 0 °, and FIG. 19B is a schematic diagram showing a state where the maximum operating angle is taken. As shown in FIG. 19A, the constant velocity universal joint 101 mainly includes an outer joint member 102, an inner joint member 103, a ball 104, and a cage 105. Eight track grooves 107 are formed on the spherical inner peripheral surface 106 of the outer joint member 102 at equal intervals in the circumferential direction and along the axial direction. Track grooves 109 facing the track grooves 107 of the outer joint member 102 are formed on the spherical outer peripheral surface 108 of the inner joint member 103 at equal intervals in the circumferential direction and along the axial direction. Eight balls 104 that transmit torque are interposed between the track grooves 107 of the outer joint member 102 and the track grooves 109 of the inner joint member 103. A cage 105 that holds the ball 104 is disposed between the spherical inner peripheral surface 106 of the outer joint member 102 and the spherical outer peripheral surface 108 of the inner joint member 103. The outer periphery of the outer joint member 102 and the outer periphery of the shaft connected to the inner joint member 103 are covered with boots, and grease is enclosed as a lubricant inside the joint (not shown).

  As shown in FIG. 19 (a), the spherical outer peripheral surface 112 of the cage 105 that fits with the spherical inner peripheral surface 106 of the outer joint member 102 and the cage 105 that fits with the spherical outer peripheral surface 108 of the inner joint member 103. The center of curvature of the spherical inner peripheral surface 113 is formed at the joint center O. On the other hand, the center of curvature Oo of the ball track center line x of the track groove 107 of the outer joint member 102 and the center of curvature Oi of the ball track center line y of the track groove 109 of the inner joint member 103 are in the joint center O. In contrast, they are offset equidistantly in the axial direction. As a result, when the joint takes an operating angle, the ball 104 is always guided on a plane that bisects the angle formed by the two axes of the outer joint member 102 and the inner joint member 103, and rotates at a constant speed between the two axes. Torque is transmitted.

  As shown in FIG. 19B, the maximum operating angle θmax, which is the main function of the fixed type constant velocity universal joint 101, is an angle at which the inlet chamfer 110 provided at the open end of the outer joint member 102 and the shaft 111 interfere with each other. Dependent. The shaft diameter d of the shaft 111 is determined for each joint size in order to ensure an allowable transmission torque. If the entrance chamfer 110 is made large, the length of the track groove 107 (hereinafter referred to as an effective track length) of the outer joint member 102 with which the ball 104 abuts is insufficient, and the ball 104 falls out of the track groove 107 and rotational torque is increased. It becomes impossible to communicate. Therefore, how to set the inlet chamfer 110 while securing the effective track length of the outer joint member 102 is an important factor in securing the operating angle. In the Zepper type constant velocity universal joint 101, the center of curvature Oo of the ball track center line x of the track groove 107 of the outer joint member 102 is offset to the opening side, which is advantageous in terms of the maximum operating angle, The angle θmax is about 47 °.

  The 8-ball type Rzeppa constant velocity universal joint 101 has a smaller track offset, a larger number of balls, and a smaller diameter than the conventional 6-ball constant velocity universal joint. Lightweight, compact, and highly efficient constant velocity universal joints with low torque loss. However, when the operating angle is 0 °, each wedge angle formed between the opposing track grooves 107 and 109 of the outer joint member 102 and the inner joint member 103 opens toward the opening side of the outer joint member 102. Therefore, due to the axial force acting on the ball from the track grooves 107 and 109, the spherical contact portions 106 and 112 of the outer joint member 102 and the cage 105 and the spherical contact portions 108 of the inner joint member 103 and the cage 105, Since the load acting on 113 is generated in a certain direction, there is a limit to further increasing efficiency and reducing heat generation.

In order to achieve higher efficiency and lower heat generation than the 8-ball type Rzeppa constant velocity universal joint 101 described above, a fixed constant velocity universal joint of a track groove intersecting type has been proposed (Patent Document 1). This constant velocity universal joint is shown in FIG. FIG. 20A is a longitudinal sectional view in a state where the operating angle is 0 °, and FIG. 20B is a schematic view showing a state where a high operating angle is taken. As shown in FIG. 20A, the constant velocity universal joint 121 mainly includes an outer joint member 122, an inner joint member 123, a ball 124, and a cage 125. This constant velocity universal joint 121 is a track groove intersection type, and although not shown, the plane including the ball track center line x of the eight track grooves 127 of the outer joint member 122 is in relation to the joint axis nn. The track grooves 127 are inclined in directions opposite to each other in the circumferential direction. Then, the ball trajectory center line y of the track groove 129 of the inner joint member 123 is based on the plane P including the joint center O in a state where the operating angle is 0 °, and the ball trajectory of the track groove 127 which is a pair of the outer joint member 122. It is formed at the center line x and mirror image symmetry.

  In the longitudinal section shown in FIG. 20A, the track groove 127 formed on the spherical inner peripheral surface 126 of the outer joint member 122 extends in an arc shape along the axial direction, and the center of curvature thereof is located at the joint center O. A track groove 129 facing the track groove 127 of the outer joint member 122 extends in an arc shape along the axial direction on the spherical outer peripheral surface 128 of the inner joint member 123, and the center of curvature is located at the joint center O. Eight balls 124 that transmit torque are interposed at intersections between the track grooves 127 of the outer joint member 122 and the track grooves 129 of the inner joint member 123. A cage 125 for holding the ball 124 is disposed between the spherical inner peripheral surface 126 of the outer joint member 122 and the spherical outer peripheral surface 128 of the inner joint member 123. The center of curvature of the spherical outer peripheral surface 132 of the cage 125 fitting with the spherical inner peripheral surface 126 of the outer joint member 122 and the spherical inner peripheral surface 133 of the cage 125 fitting with the spherical outer peripheral surface 128 of the inner joint member 123 are , Both are formed at the joint center O. In this constant velocity universal joint 121, the curvature centers of the ball track center lines x and y of the track grooves 127 and 129 of the outer joint member 122 and the inner joint member 123 are not offset in the axial direction with respect to the joint center O. The inclined track grooves 127 and 129 intersect with each other, and when the joint takes an operating angle due to the ball 124 being interposed at the intersecting portion, an angle formed by both axes of the outer joint member 122 and the inner joint member 123 is determined. The ball 124 is always guided on a bisecting plane, and rotational torque is transmitted at a constant speed between the two axes.

  In the track groove intersecting type fixed constant velocity universal joint 121 described above, the track grooves 127 and 129 of the outer joint member 122 and the inner joint member 123 are adjacent track grooves in the circumferential direction, and the inclination directions are opposite to each other. Therefore, forces in opposite directions from the ball 124 act on the pocket portions 125a adjacent to the circumferential direction of the cage 125. The cage 125 is stabilized at the joint center O position by the forces in the opposite directions. Therefore, the contact force between the spherical outer circumferential surface 132 of the cage 125 and the spherical inner circumferential surface 126 of the outer joint member 122 and the contact between the spherical inner circumferential surface 133 of the cage 125 and the spherical outer circumferential surface 128 of the inner joint member 123. The force is suppressed, the joint operates smoothly at high loads and at high speeds, torque loss and heat generation are suppressed, and durability is improved.

  Although the above-mentioned fixed type constant velocity universal joint 121 is excellent as a low heat generation joint, as shown in FIG. 20B, when the inlet chamfer 130 of the outer joint member 122 is enlarged, the center of curvature of the track groove 127 and the joint are increased. Since the center O is coincident, the effective track length of the track groove 127 of the outer joint member 122 is insufficient due to the structure, and when the high operating angle θ is taken, the ball 124 falls out of the track groove 127, and the high There is a problem that the operating angle cannot be achieved.

JP 2009-250365 A

  In view of the above-described problems of the prior art, the inventors set straight track grooves on the opening side from the joint center O in order to increase the angle in the fixed constant velocity universal joint of the track groove intersecting type disclosed in Patent Document 1. We considered to make it. This constant velocity universal joint is shown in FIG. 17, FIG. 17 (a) shows a longitudinal section, and FIG. 17 (b) shows the right side of FIG. 17 (a). As shown in FIG. 17 (a), in this constant velocity universal joint 141, the track grooves 147 and 149 of the outer joint member 142 and the inner joint member 143 are crossing types, and the track groove 147 of the outer joint member 142 is the center of the joint. A track groove 147a having an arc-shaped ball trajectory center line xa centered on the joint center O on the back side from O, and a track groove 147b having a straight ball trajectory center line xb on the opening side from the joint center O. Become. On the other hand, the track groove 149 of the inner joint member 143 includes a track groove 149b having a linear ball raceway center line yb on the back side from the joint center O, and a circle centering on the joint center O on the opening side from the joint center O. A track groove 149a having an arcuate ball trajectory centerline ya.

  As shown in FIG. 17 (b), the track grooves 147, 149 are inclined in the circumferential direction with respect to the joint axis line, and the inclined directions of the track grooves 147A, 147B and 149A are adjacent to each other in the circumferential direction. The inclination direction is formed in the opposite direction at 149B. Then, balls 144 are arranged at the intersections of the track grooves 147A, 149A and 147B, 149B that form a pair of the outer joint member 142 and the inner joint member 143. Therefore, when torque is transmitted at an operating angle of 0 ° as shown in the figure, the direction of opening of the wedge angle formed between the track grooves 147A and 149A and the direction of opening of the wedge angle formed between 147B and 149B are shown. Are opposite directions, and forces in opposite directions from the ball 144 act on the pocket portions 145a adjacent to each other in the circumferential direction of the cage 145. Due to the forces in the opposite directions, the cage 145 is stabilized at the joint center O position. Therefore, the contact force between the spherical outer circumferential surface 152 of the cage 145 and the spherical inner circumferential surface 146 of the outer joint member 142 and the contact between the spherical inner circumferential surface 153 of the cage 145 and the spherical outer circumferential surface 148 of the inner joint member 143. The force is suppressed, the joint operates smoothly at high loads and at high speeds, torque loss and heat generation are suppressed, and durability is improved.

  As described above, the effective track length can be increased by forming the linear track groove 147b on the opening side from the joint center O of the track groove 147 of the outer joint member 142 in the track groove intersection type. It has been found that there is a problem in terms of suppressing torque loss and heat generation of the joint when taking a frequently used operating angle. The reason for this will be described with reference to FIG. Since the track grooves 147 and 149 and the ball 144 are normally in contact with each other at a contact angle (about 30 ° to 45 °), the track grooves 147 and 149 and the ball 144 are connected to each other as shown in FIG. The track grooves 147 and 149 are in contact with each other at positions indicated by broken lines on the side surfaces of the track grooves 147 and 149 slightly apart from the groove bottom of 149. When the joint takes an operating angle, each ball 144 has a wedge angle component (not shown) due to the intersection of the track grooves 147 and 149 and a wedge due to the joint radial expansion between the groove bottoms of the track grooves 147 and 149. Both angular components α act. Among them, with respect to the wedge angle component due to the intersection of the track grooves 147 and 149, since the inclination directions of the track grooves 147 and 149 are alternately opposite, the force in the direction opposite to the pocket portion 145a of the cage 145 from the ball 144 Acts so that they cancel each other out and balance the power.

  However, as shown in FIG. 18, the wedge angle component α due to the joint radial expansion between the groove bottoms of the track grooves 147 and 149 is 0 ° to 90 ° and 270 ° to 360 ° in FIG. The ball 144 in the phase range is positioned in the linear track grooves 147b and 149b, and a force toward the opening acts on the ball 144 in the phase range by the wedge angle component α1 that opens toward the opening. On the other hand, since the ball 144 in the phase range of 90 ° to 270 ° is positioned in the arc-shaped track grooves 147a and 149a, the wedge angle component α2 generated by the radial expansion of the joint is 0 in the balls in this phase range. Therefore, the pushing force of the ball 144 is not generated. Therefore, for each ball 144, when the wedge angle component due to the intersection of the track grooves 147 and 149 and the wedge angle component α due to the joint radial expansion between the groove bottoms of the track grooves 147 and 149 are combined, the cage 145 The forces acting from the balls 144 are not balanced on the pocket portions 145a, and the spherical contact portions 152 and 146 between the cage 145 and the outer joint member 142 and the spherical contact portions 153 and 148 between the cage 145 and the inner joint member 143 are contacted. The problem arises that the force cannot be reduced. In particular, it has been found that there are significant problems in terms of torque loss and suppression of heat generation in the range of operating angles that are frequently used and include operating angles.

  In view of the above problems, the present invention is a compact fixed type constant velocity universal joint that has low torque loss and heat generation, is highly efficient, can take a high operating angle, and is excellent in strength and durability at a high operating angle. The purpose is to provide.

  As a result of various studies to achieve the above object, the present inventors have found that the track grooves intersect in the circumferential direction in order to achieve high efficiency with little torque loss and heat generation, and in the axial direction with respect to the joint center. The arc-shaped first track groove portion having a center of curvature without offset covers a range of frequently used operating angles and is different from the first track groove portion in order to increase the effective track length with respect to the maximum operating angle. The second track groove portion having a shape has led to a novel idea of covering a range of a high operating angle that is not frequently used.

As technical means for achieving the above-described object, the present invention provides an outer joint member having a plurality of track grooves extending in the axial direction on a spherical inner peripheral surface and having an opening side and a back side that are separated in the axial direction. An inner joint member in which a plurality of track grooves paired with the track grooves of the outer joint member are formed on the spherical outer peripheral surface, and the track groove of the outer joint member and the track groove of the inner joint member are interposed. A plurality of balls for transmitting torque, and a cage having a spherical outer peripheral surface and a spherical inner peripheral surface that hold the balls and fit to the spherical inner peripheral surface of the outer joint member and the spherical outer peripheral surface of the inner joint member; The track groove of the outer joint member includes a first track groove portion located on the back side and a second track groove portion located on the opening side, and the first track groove portion. Is the center of the joint An arcuate portion having a center of curvature with no offset in the axial direction, and inclined in the circumferential direction with respect to the axis of the joint, and the inclined direction is opposite to each other in the first track groove portions adjacent in the circumferential direction. The second track groove portion has a shape different from that of the first track groove portion in order to increase an effective track length with respect to a maximum operating angle, and the first track groove portion and the second track groove portion are formed. The track groove portion is connected on the opening side in the axial direction from the joint center, and the track groove of the inner joint member has the operating angle of 0 ° with respect to a plane including the joint center as a reference. characterized in that it is formed in the paired track grooves and the mirror image symmetry of the member. Here, the axis of the joint means a longitudinal axis serving as a rotation center of the joint, and indicates an axis NN of the joint in an embodiment described later. The same applies to the axis of the joint described in the claims.

  With the above configuration, it is possible to achieve a compact fixed type constant velocity universal joint that has low torque loss and heat generation, high efficiency, high operating angle, and excellent strength and durability at high operating angle. it can.

  Specifically, an angle formed by a straight line connecting a point where the first track groove portion and the second track groove portion are connected to the joint center with respect to a plane including the joint center when the operating angle is 0 °. β can be set as appropriate according to the state of use. If the angle of β is set to 3 to 10 ° in consideration of the normal operating angle range of the constant velocity universal joint for automobiles, it can be widely used for various types of vehicles. Here, the angle β is defined as the smallest of the angles formed by the straight line and the straight line on the plane. The same applies to the embodiments and the claims.

  By disposing the center of curvature of the arc of the first track groove portion on the axis of the joint, the track groove depth can be made uniform and processing can be facilitated. Further, by offsetting the center of curvature of the arc of the first track groove portion in the radial direction from the axis of the joint, the depth of the track groove on the back side of the joint can be adjusted, and the optimum track groove depth can be adjusted. Can be secured.

  The spherical outer peripheral surface and the spherical inner peripheral surface of the cage have a center of curvature that is offset in the axial direction with respect to the joint center O, so that the thickness of the cage increases toward the opening side, and in particular, a high operating angle. The strength of the cage at the time can be ensured.

  The second track groove portion includes an arc-shaped portion. Further, the second track groove portion is composed of an arc-shaped portion and a linear portion, and this linear portion is smoothly connected to the first track groove portion. Thereby, the effective track length can be increased and the maximum operating angle can be increased.

  Furthermore, the arc-shaped portion of the second track groove portion has a center of curvature that is radially outward from the first track groove portion and offset toward the opening side in the axial direction from the joint center. As a result, compactness can be achieved, the effective track length can be increased, and the maximum operating angle can be increased.

  The inclination angle in the circumferential direction of the second track groove portion can be gradually decreased toward the opening side. Moreover, you may make it a 2nd track groove part have a part which does not incline in the circumferential direction with respect to the axis line of a coupling. Thereby, the space | interval of the side which the 2nd track groove part adjacent in the circumferential direction approached is expanded, and the difference of each space | interval can be made small in the circumferential direction. As a result, the difference between the contact area on the opening side of each spherical inner peripheral surface of the outer joint member and the difference in the contact area on the back side of each spherical outer peripheral surface of the inner joint member can be reduced. The spherical contact portions of the member and the inner joint member can be arranged with good balance, and further smoothing of the operation can be achieved.

  By setting the number of torque transmission balls to 8 or 10, it is possible to realize a light-weight, compact, high-efficiency fixed type constant velocity universal joint capable of taking a high operating angle, and thus a drive shaft of an automobile.

  According to the present invention, it is possible to realize a compact fixed type constant velocity universal joint that has low torque loss and heat generation, is highly efficient, can take a high operating angle, and is excellent in strength and durability at a high operating angle. .

It is the fragmentary longitudinal cross-section and side view of the fixed type constant velocity universal joint which concern on the 1st Embodiment of this invention. It is the fragmentary longitudinal cross-section and side view of the outer joint member of said fixed type constant velocity universal joint. It is a figure which shows the outer peripheral surface and side surface of the inner side coupling member of said fixed type constant velocity universal joint. It is a fragmentary longitudinal cross-section which shows the detail of the track groove of an outer joint member. It is a longitudinal cross-sectional view which shows the detail of the track groove of an inner side coupling member. It is an outline figure showing the state where a joint took the maximum operating angle. It is a perspective view of an outer joint member and an inner joint member. It is a figure which shows the state which used said fixed type constant velocity universal joint for the drive shaft of a motor vehicle. It is a longitudinal cross-sectional view of the outer joint member of the fixed type constant velocity universal joint which concerns on the 2nd Embodiment of this invention. It is a longitudinal cross-sectional view of the outer joint member of the fixed type constant velocity universal joint which concerns on the 3rd Embodiment of this invention. It is a fragmentary longitudinal cross-sectional view of the fixed type constant velocity universal joint which concerns on the 4th Embodiment of this invention. It is a fragmentary longitudinal cross-sectional view of the outer joint member of the fixed type constant velocity universal joint which concerns on the 5th Embodiment of this invention. It is a longitudinal cross-sectional view of the outer joint member of said fixed type constant velocity universal joint. It is a longitudinal cross-sectional view of the inner joint member of said fixed type constant velocity universal joint. It is a fragmentary longitudinal cross-section which shows the inner peripheral shape of the outer joint member of said fixed type constant velocity universal joint. It is a figure which shows the outer periphery shape of the inner side coupling member of said fixed type constant velocity universal joint. It is a figure explaining the technical knowledge in the process leading to the present invention. It is a figure explaining the technical knowledge in the process leading to the present invention. It is a longitudinal cross-sectional view of the fixed type constant velocity universal joint of a prior art. It is a longitudinal cross-sectional view of the fixed type constant velocity universal joint of a prior art.

  An embodiment of the present invention will be described with reference to FIGS.

  A first embodiment of the present invention is shown in FIGS. 1 shows a fixed type constant velocity universal joint according to the first embodiment, FIG. 1 (a) is a partial longitudinal sectional view, and FIG. 1 (b) is a right side view of FIG. 1 (a). . The constant velocity universal joint 1 mainly includes an outer joint member 2, an inner joint member 3, a ball 4 and a cage 5. As shown in FIGS. 1B, 2 and 3, the eight track grooves 7 and 9 of the outer joint member 2 and the inner joint member 3, respectively, are inclined in the circumferential direction with respect to the joint axis NN. In addition, the inclination directions of the track grooves 7A, 7B and 9A, 9B adjacent to each other in the circumferential direction are formed in opposite directions. Then, eight balls 4 are arranged at the intersections of the track grooves 7A, 9A and 7B, 9B which form a pair of the outer joint member 2 and the inner joint member 3. Details of the track grooves 7 and 9 will be described later.

  A longitudinal section of the joint is shown in FIG. In this specification, the term “ball trajectory centerline” will be used to describe the shape and shape of the track groove extending in the axial direction, such as an inclined state and a curved state. Here, the ball trajectory center line means a locus drawn by the center of the ball when the ball arranged in the track groove moves along the track groove. Therefore, the inclination state of the track groove is the same as the inclination state of the ball track center line, and the arc shape or the straight state of the track groove is the arc shape or straight state of the ball track center line. The same. The track groove 7 of the outer joint member 2 has a ball track center line X, and the track groove 7 includes a first track groove portion 7a having an arc-shaped ball track center line Xa with the joint center O as a center of curvature, The second track groove portion 7b has an arc-shaped ball trajectory center line Xb curved in the opposite direction to the first track groove portion 7a, and the second track is formed on the ball track center line Xa of the first track groove portion 7a. The ball track center line Xb of the groove portion 7b is smoothly connected. On the other hand, the track groove 9 of the inner joint member 3 has a ball track center line Y, and the track groove 9 includes a first track groove portion 9a having an arc-shaped ball track center line Ya with the joint center O as the center of curvature. The second track groove portion 9b has an arc-shaped ball trajectory center line Yb that is curved in the opposite direction to the first track groove portion 9a. The second track groove portion 9a has a second track groove center line Ya. The ball track center line Yb of the track groove portion 9b is smoothly connected. Thus, the ball track center lines Xa and Ya of the first track groove portions 7a and 9a and the ball track center lines Xb and Yb of the second track groove portions 7b and 9b are different in shape. By arranging the centers of curvature of the ball track center lines Xa, Ya of the first track groove portions 7a, 9a on the joint center O, that is, the joint axis NN, the track groove depth can be made uniform. And processing can be facilitated. Although not shown, the cross-sectional shape of the track grooves 7 and 9 is an oval shape or a Gothic arch shape. The track grooves 7 and 9 and the ball 4 have a contact angle (about 30 ° to 45 °). The contact is a so-called angular contact. Therefore, the ball 4 is in contact with the side surfaces of the track grooves 7 and 9 that are slightly away from the groove bottoms of the track grooves 7 and 9.

  Based on FIG. 2, the state in which the track groove 7 of the outer joint member 2 is inclined in the circumferential direction with respect to the joint axis NN will be described in detail. FIG. 2A shows a partial longitudinal section of the outer joint member 2, and FIG. 2B shows the right side surface of the outer joint member 2. The track grooves 7 of the outer joint member 2 are given the reference numerals of the track grooves 7A and 7B due to the difference in the inclination direction. As shown in FIG. 2A, the plane M including the ball track center line X of the track groove 7A and the joint center O is inclined by an angle γ with respect to the joint axis NN. The track groove 7B adjacent to the track groove 7A in the circumferential direction is not shown, but the plane M including the ball track center line X and the joint center O of the track groove 7B is in relation to the joint axis NN. The track groove 7A is inclined by an angle γ in the opposite direction to the inclination direction of the track groove 7A. In the present embodiment, the entire area of the ball track center line X of the track groove 7A, that is, both the ball track center line Xa of the first track groove portion 7a and the ball track center line Xb of the second track groove portion 7b are on the plane M. Is formed. However, the present invention is not limited to this, and a mode in which only the ball trajectory center line Xa of the first track groove portion 7a is included in the plane M can also be implemented. Therefore, a plane M including at least the ball track center line Xa of the first track groove 7a and the joint center O is inclined in the circumferential direction with respect to the joint axis NN, and the inclined direction is adjacent to the circumferential direction in the first direction. The track grooves 7a may be formed in opposite directions.

  Here, the reference numerals of the track grooves will be supplemented. When referring to the entire track groove of the outer joint member 2, reference numeral 7 is attached, and the first track groove part is assigned 7a, and the second track groove part is given 7b. Further, when differentiating track grooves having different inclination directions, reference numerals 7A and 7B are attached, and reference numerals 7Aa and 7Ba are attached to the first track groove parts, and reference signs 7Ab and 7Bb are attached to the second track groove parts. The track grooves of the inner joint member 3 to be described later are also given the same reference numerals.

Next, a state where the track groove 9 of the inner joint member 3 is inclined in the circumferential direction with respect to the joint axis NN will be described in detail with reference to FIG. 3 (b) shows the outer peripheral surface of the inner joint member 3, FIG. 3 (a) shows the left side surface of the inner joint member 3, and FIG. 3 (c) shows the right side surface. The track grooves 9 of the inner joint member 3 are denoted by the reference numerals of the track grooves 9A and 9B because of the difference in inclination direction. As shown in FIG. 3B, the plane Q including the ball track center line Y and the joint center O of the track groove 9A is inclined by an angle γ with respect to the joint axis NN. The track groove 9B adjacent to the track groove 9A in the circumferential direction is not shown, but the plane Q including the ball track center line Y and the joint center O of the track groove 9B is in relation to the joint axis NN. The track groove 9A is inclined by an angle γ in the direction opposite to the inclination direction of the track groove 9A. The inclination angle γ is preferably set to 4 ° to 12 ° in consideration of the operability of the constant velocity universal joint 1 and the spherical surface width F on the closest side of the track groove of the inner joint member 3. Further, like the outer joint member described above, in this embodiment, the entire region of the ball track center line Y of the track groove 9A, that is, the ball track center line Ya of the first track groove portion 9a and the balls of the second track groove portion 9b. Both of the track center lines Yb are formed on the plane Q. However, the present invention is not limited to this, and a mode in which only the ball trajectory center line Ya of the first track groove portion 9a is included in the plane Q can also be implemented. Therefore, the plane Q including at least the ball track center line Ya of the first track groove 9a and the joint center O is inclined in the circumferential direction with respect to the joint axis NN, and the inclined direction is adjacent to the circumferential direction in the first direction. The track grooves 9a may be formed in opposite directions. The ball trajectory center line Y of the track groove 9 of the inner joint member 3 is based on the plane P including the joint center O at the operating angle of 0 ° as a reference, and the ball trajectory center line of the track groove 7 that forms a pair of the outer joint member 2 It is formed in the X and mirror image symmetry.

  Based on FIG. 4, the detail of the track groove seen from the longitudinal cross-section of the outer joint member 2 is demonstrated. 4 is a cross-sectional view of the track groove 7A shown in FIG. 2A as viewed on a plane M including the ball trajectory center line X and the joint center O in FIG. Therefore, strictly speaking, it is not a longitudinal sectional view in a plane including the joint axis NN, but shows a section inclined by an angle γ. FIG. 4 shows the track groove 7A of the outer joint member 2, but the track groove 7B is the same as the track groove 7A except for the inclination direction opposite to the track groove 7A. Since there is, explanation is omitted. A track groove 7A is formed in the spherical inner peripheral surface 6 of the outer joint member 2 along the axial direction. The track groove 7A has a ball track center line X, and the track groove 7A has a first track groove portion 7Aa having an arc-shaped ball track center line Xa with the joint center O as the center of curvature (no axial offset). And an arcuate ball trajectory center line Xb having a center of curvature at a point Oo1 offset from the joint center O toward the axial opening side, radially outside the ball trajectory center line Xa of the first track groove portion 7Aa. 2 track groove portions 7Ab. Accordingly, the arc-shaped ball track center line Xb of the second track groove portion 7Ab is curved in the opposite direction to the arc-shaped ball track center line Xa of the first track groove portion 7Aa. An end A on the opening side of the ball track center line Xa of the first track groove portion 7Aa is a point where a straight line connecting the joint center O and the offset point Oo1 intersects the ball track center line X, and the end A and the joint center Let L be the straight line connecting O. The ball track center line Xb of the second track groove portion 7Ab is smoothly connected to the end portion A. That is, the end A is a connection point between the first track groove 7Aa and the second track groove 7Ab. A perpendicular line K and a straight line L at the joint center O of the joint axis N′-N ′ projected onto the plane M (see FIG. 2A) including the ball track center line X of the track groove 7A and the joint center O (see FIG. 2A). The angle β ′ formed is inclined by an angle γ with respect to the joint axis NN. The perpendicular K is on the plane P including the joint center O in the state where the operating angle is 0 °. Accordingly, the angle β formed by the straight line L with respect to the plane P including the joint center O in the state where the operating angle is 0 ° in the present invention has a relationship of sinβ = sinβ ′ × cosγ. Further, β is an angle obtained by projecting β ′ onto a plane including the joint axis N-N, that is, a plane M when the inclination angle γ = 0 °, by inclining the plane M with respect to the perpendicular K. = Tan β ′ × cos γ The former and the latter are almost the same numerically within the practical range, but the former is adopted here. Although the first track groove portion 7Aa and the second track groove portion 7Ab of the outer joint member 2 are each formed by one arc, the present invention is not limited to this, and a plurality of track groove depths and the like are taken into consideration. You may form with the circular arc.

  Similarly, details of the track grooves will be described based on a longitudinal section of the inner joint member 3 based on FIG. 5 is a cross-sectional view of the track groove 9A shown in FIG. 3B as seen from the plane Q including the ball trajectory center line Y and the joint center O. In FIG. Therefore, similarly to FIG. 4, strictly, it is not a longitudinal sectional view in a plane including the joint axis NN, but shows a section inclined by an angle γ. FIG. 5 shows the track groove 9A of the inner joint member 3, but the track groove 9B is the same as the track groove 9A except for the inclination direction opposite to the track groove 9A. Since there is, explanation is omitted. A track groove 9A is formed in the spherical outer peripheral surface 8 of the inner joint member 3 along the axial direction. The track groove 9A has a ball track center line Y, and the track groove 9A has a first track groove portion 9Aa having an arc-shaped ball track center line Ya with the joint center O as the center of curvature (no axial offset). And an arc-shaped ball trajectory center line Yb having a center of curvature at a point Oi1 offset from the joint center O in the radial direction outside the ball trajectory center line Ya of the first track groove portion 9Aa. 2 track groove portions 9Ab. The back end B of the first track groove 9Aa is a point where a straight line R connecting the joint center O and the offset point Oi1 intersects the ball track center line Y, and the second track groove 9Ab is formed at the end B. Are smoothly connected. That is, the end B is a connection point between the first track groove 9Aa and the second track groove 9Ab. A perpendicular line K and a straight line R at the joint center O of the joint axis N′-N ′ projected onto the plane Q (see FIG. 3B) including the ball track center line Y of the track groove 9A and the joint center O (see FIG. 3B). The angle β ′ formed is inclined by an angle γ with respect to the joint axis NN. The perpendicular K is on the plane P including the joint center O in the state where the operating angle is 0 °. Therefore, the angle β formed with respect to the plane P including the joint center O when the straight line R is at the operating angle of 0 ° has a relationship of sin β = sin β ′ × cos γ. Further, β is assumed to be obtained by projecting β ′ onto a plane including the joint axis N-N, that is, a plane Q when the inclination angle γ = 0 °, by inclining the plane Q with respect to the perpendicular K. = Tan β ′ × cos γ The former and the latter are almost the same numerically within the practical range, but the former is adopted here. Similarly to the track groove of the outer joint member 2 described above, the first track groove portion 9Aa and the second track groove portion 9Ab of the inner joint member 3 are each formed by a plurality of arcs in consideration of the track groove depth and the like. It may be formed.

  Next, an angle β formed by the straight lines L and R with respect to the plane P including the joint center O in a state where the operating angle is 0 ° will be described. When the operating angle θ is taken, the ball 4 moves by θ / 2 with respect to the plane P including the joint center O of the outer joint member 2 and the inner joint member 3. The angle β is determined from ½ of the frequently used operating angle, and the range of the track groove with which the ball 4 contacts is determined within the frequently used operating angle range. Here, the operating angle that is frequently used is defined. First, the common angle of the joint refers to an operating angle generated in a fixed type constant velocity universal joint of the front drive shaft when the steering is in a straight traveling state in an automobile when one person rides on a horizontal and flat road surface. The service angle is usually selected and determined between 2 ° and 15 ° according to the design conditions for each vehicle type. The frequently used operating angle is not the high operating angle that occurs when the above-mentioned automobile is turned right or left at an intersection, for example, but the operating angle that occurs in a fixed constant velocity universal joint on a curved road that runs continuously This is also determined according to the design conditions for each vehicle type. The operating angle that is frequently used is targeted at a maximum of 20 °. As a result, the angle β formed by the straight lines L and R with respect to the plane P including the joint center O in a state where the operating angle is 0 ° is set to 3 ° to 10 °. However, the angle β is not limited to 3 ° to 10 °, and can be appropriately set according to the design conditions of the vehicle type. By setting the angle β to 3 ° to 10 °, it can be used for various types of vehicles.

  4, the end A of the ball track center line Xa of the first track groove portion 7Aa in FIG. 4 is the position of the ball when moved to the most opening side along the axial direction when the operating angle is frequently used. It becomes the center position. Similarly, in FIG. 5, in the inner joint member 3, when the end B of the ball track center line Ya of the first track groove 9 </ b> Aa moves to the farthest side along the axial direction at the operating angle where the usage frequency is high. The center position of the ball. Since the setting is made in this way, in the range of the operating angle that is frequently used, the ball 4 has the first track groove portions 7Aa and 9Aa of the outer joint member 2 and the inner joint member 3 and 7Ba opposite in inclination direction, Since it is located at 9Ba (see FIG. 2 and FIG. 3), a force in the opposite direction from the ball 4 acts on the pocket 5a adjacent to the circumferential direction of the cage 5, and the cage 5 is stable at the position of the joint center O. (See FIG. 1). For this reason, the contact force between the spherical outer peripheral surface 12 of the cage 5 and the spherical inner peripheral surface 6 of the outer joint member 2 and the contact between the spherical inner peripheral surface 13 of the cage 5 and the spherical outer peripheral surface 8 of the inner joint member 3. The force is suppressed, the joint operates smoothly at high loads and at high speeds, torque loss and heat generation are suppressed, and durability is improved.

  FIG. 6 shows a state in which the constant velocity universal joint of the present embodiment takes the maximum operating angle. The track groove 7A of the outer joint member 2 has an arcuate shape with a curvature center at a point Oo1 offset from the joint center O to the axial opening side on the radial outer side of the ball track center line Xa of the first track groove portion 7Aa. A second track groove portion 7Ab having a ball track center line Xb is formed on the opening side. In the compact design, the presence of the second track groove portion 7Ab makes it possible to increase the effective track length and increase the maximum operating angle. Therefore, as shown in the drawing, even when the maximum operating angle θmax is set to a high angle of about 50 °, the ball 4 can be kept in contact with the track groove 7Ab with the necessary and sufficient entrance chamfer 10 provided.

  Incidentally, in the range of the high operating angle, the balls 4 arranged in the circumferential direction have the first track groove portions 7Aa, 9Aa (see 7Ba, 9Ba, FIG. 2 (a) and FIG. 3 (b)) and the second track groove portion. 7Ab and 9Ab (7Bb, 9Bb, see FIG. 2 (a) and FIG. 3 (b)). Along with this, the forces acting from the balls 4 on the pockets 5a of the cage 5 are not balanced, and the spherical contact portions 12 and 6 between the cage 5 and the outer joint member 2 and the cage 5 and the inner joint member 3 Although the contact force of the spherical contact portions 13 and 8 is generated, the constant velocity universal joint 1 of the present embodiment can suppress torque loss and heat generation comprehensively because the frequency of use is low in the high operating angle range. Therefore, it is possible to realize a compact fixed type constant velocity universal joint that has a small torque loss and heat generation, is highly efficient, can take a high operating angle, and is excellent in strength and durability at a high operating angle.

  In FIG. 7, the perspective view of the outer joint member 2 and the inner joint member 3 of the constant velocity universal joint of this embodiment is shown. This perspective view three-dimensionally shows the track grooves described so far. As shown in FIG. 7A, track grooves 7A and 7B inclined in the circumferential direction with respect to the joint axis NN (not shown) are alternately formed on the spherical inner peripheral surface 6 of the outer joint member 2. The inclination directions are alternately formed in opposite directions. The track grooves 7A and 7B are composed of first track groove portions 7Aa and 7Ba and second track groove portions 7Ab and 7Bb, respectively. An inlet chamfer 10 is provided at the open end of the outer joint member 2. Further, as shown in FIG. 7B, track grooves 9A and 9B inclined in the circumferential direction with respect to the joint axis NN (not shown) are alternately formed on the spherical outer peripheral surface 8 of the inner joint member 3. The inclination directions are alternately formed in opposite directions. The track grooves 9A and 9B are composed of first track groove portions 9Aa and 9Ba and second track groove portions 9Ab and 9Bb, respectively.

  FIG. 8 shows an automotive front drive shaft 20 to which the fixed type constant velocity universal joint 1 of the present embodiment is applied. The fixed type constant velocity universal joint 1 is connected to one end of the intermediate shaft 11, and a sliding tripod type constant velocity universal joint 15 is connected to the other end. Between the outer peripheral surface of the fixed type constant velocity universal joint 1 and the outer peripheral surface of the shaft 11 and between the outer peripheral surface of the sliding tripod type constant velocity universal joint 15 and the outer peripheral surface of the shaft 11, respectively, 16b are attached and fixed by boot bands 18a, 18b, 18c and 18d. Grease as a lubricant is sealed inside the joint. Since the fixed type constant velocity universal joint 1 of the present embodiment is used, a lightweight and compact automobile drive shaft 20 is realized that has low torque loss and heat generation, high efficiency, and a high operating angle.

  Next, a fixed type constant velocity universal joint according to a second embodiment of the present invention will be described with reference to FIG. FIG. 9 shows only the outer joint member of the fixed type constant velocity universal joint of the present embodiment, and is a cross-sectional view as seen in a plane M including the ball track center line X of the track groove 7A and the joint center O, as in FIG. (See FIG. 2A. The same applies to the corresponding diagrams of the following embodiments.) Further, the upper half of the outer joint member in the radial direction from the axis is shown. This fixed type constant velocity universal joint is different from the fixed type constant velocity universal joint of the first embodiment described above in that the second track groove portion is composed of an arcuate portion and a linear portion, and other configurations. Is the same as in the first embodiment. Parts having the same functions as those in the first embodiment are denoted by the same reference numerals, and redundant description is omitted.

The end A on the opening side of the ball track center line Xa of the first track groove portion 7a of the outer joint member 2 is the same as in the first embodiment. The center of curvature Oo2 of the ball track center line Xb of the second track groove 7b is offset from the straight line L connecting the joint center O and the end A by f1 toward the opening. Therefore, the linear portion of the ball track center line Xb of the second track groove portion 7b is connected to the end A on the opening side of the ball track center line Xa of the first track groove portion 7a. The linear portion of the ball track center line Xb and the arc-shaped portion of the second track groove portion 7b are connected at a point C. Although illustration is omitted, the track orbit center line Y of the track groove 9 of the inner joint member 3 is a track groove that forms a pair of the outer joint member 2 with respect to a plane P including the joint center O in the state of an operating angle of 0 °. It is formed in the ball raceway center line X and the mirror image symmetry of 7. Regarding the circumferentially inclined state of the joints of the track grooves 7 and 9 of the outer joint member 2 and the inner joint member 3 with respect to the axis NN, the configuration of the cage 5 and the action of the joint, the fixed type of the first embodiment, etc. Since it is the same as that of a quick universal joint, duplication description is abbreviate | omitted.

  A fixed type constant velocity universal joint according to a third embodiment of the present invention will be described with reference to FIG. FIG. 10 also shows only the outer joint member of the fixed type constant velocity universal joint. In this fixed type constant velocity universal joint, the center of curvature of the arc-shaped ball raceway center line of the first track groove portion is relative to the joint center O as compared with the fixed type constant velocity universal joint of the first embodiment described above. There is no offset in the axial direction, but the offset of the joint in the radial direction with respect to the axis NN of the joint is different, and the configuration of the arc-shaped ball trajectory center line of the second track groove is adjusted accordingly. The configuration is the same as in the first embodiment. Also in this embodiment, parts having the same functions as those in the first embodiment are denoted by the same reference numerals, and redundant description is omitted. The same applies to the following embodiments.

The end A on the opening side of the ball track center line Xa of the first track groove portion 7a of the outer joint member 2 is the same as in the first embodiment. However, the curvature center Oo3 of the ball track center line Xa of the first track groove portion 7a is not axially offset with respect to the joint center O, but is offset by f2 in the radial direction with respect to the joint axis NN. Yes. That is, it is offset by f2 in the radial direction on the plane P including the joint center O in a state where the operating angle including the perpendicular K is 0 °. Accordingly, the position of the curvature center Oo4 of the ball track center line Xb of the second track groove portion 7b is adjusted so as to be smoothly connected to the ball track center line Xa of the first track groove portion 7a. With this configuration, the depth of the track groove on the back side of the joint can be adjusted. Also in the fixed type constant velocity universal joint of the present embodiment, although not shown, the ball track center line Y of the track groove 9 of the inner joint member 3 has a plane P including the joint center O in an operating angle of 0 °. as reference, it is formed in the ball raceway center line X and the mirror image symmetry of the track grooves 7 forming a pair of the outer joint member 2. Regarding the circumferentially inclined state of the joints of the track grooves 7 and 9 of the outer joint member 2 and the inner joint member 3 with respect to the axis NN, the configuration of the cage 5 and the action of the joint, the fixed type of the first embodiment, etc. Since it is the same as that of a quick universal joint, duplication description is abbreviate | omitted.

  A fixed type constant velocity universal joint according to a fourth embodiment of the present invention will be described with reference to FIG. The fixed type constant velocity universal joint of this embodiment has the center of curvature of the spherical outer peripheral surface and the spherical inner peripheral surface of the cage with respect to the joint center O as compared with the fixed type constant velocity universal joint of the first embodiment. The other differences are the same as in the first embodiment except that the offset is made in the axial direction.

  Fig.11 (a) shows the partial longitudinal cross-section of a fixed type constant velocity universal joint, and FIG.11 (b) shows the longitudinal cross-section of a holder | retainer. The center of curvature Oc1 of the spherical outer peripheral surface 12 of the cage 5 and the center of curvature Oc2 of the spherical inner peripheral surface 13 are offset in the axial direction by f3 with respect to the joint center O. With this offset configuration, the thickness of the cage 5 increases toward the opening side, and the strength of the cage 5 particularly at a high operating angle can be improved. As described above, in the range of the high operating angle, the balls 4 arranged in the circumferential direction have the first track groove portions 7Aa, 9Aa (7Ba, 9Ba, see FIGS. 2A and 3B) and the second. The track groove portions 7Ab and 9Ab (7Bb and 9Bb, see FIGS. 2A and 3B) are temporarily separated and positioned. In this case, a force of pressing the ball 4 located in the second track groove portions 7Ab and 9Ab (7Bb and 9Bb) to the pocket portion 5a of the cage 5 acts on the opening side, but the cage 5 moves toward the opening side. Since the thickness of is increased, the strength of the cage 5 can be improved. Further, the depth of the track grooves 7a and 9b on the back side can be increased. Also in this embodiment, the circumferential inclination state with respect to the joint axis NN of the track grooves 7 and 9 of the outer joint member 2 and the inner joint member 3, the configuration of the cage 5, and the action of the joint are the first. Since it is the same as that of the fixed type constant velocity universal joint of embodiment, duplication description is abbreviate | omitted.

  A fixed type constant velocity universal joint according to a fifth embodiment of the present invention will be described with reference to FIGS. The fixed type constant velocity universal joint of this embodiment is different from the fixed type constant velocity universal joint of the first embodiment in the configuration of the second track groove portion, and other configurations are the same as those of the first embodiment. The same.

  As shown in FIG. 12, the vertical cross section of the fixed type constant velocity universal joint of the present embodiment has substantially the same shape as that of the first embodiment, including the shape of the second track groove portion. That is, the track groove 7 of the outer joint member 2 has a ball track center line X, and the track groove 7 has a first track groove portion 7a having an arc-shaped ball track center line Xa with the joint center O as the center of curvature. The second track groove portion 7b has an arc-shaped ball track center line Xb that is curved in the opposite direction to the first track groove portion 7a. The second track groove portion 7a has a second track groove center line Xa. The ball track center line Xb of the track groove 7b is smoothly connected. On the other hand, the track groove 9 of the inner joint member 3 has a ball track center line Y, and the track groove 9 includes a first track groove portion 9a having an arc-shaped ball track center line Ya with the joint center O as the center of curvature. The second track groove portion 9b has an arc-shaped ball trajectory center line Yb that is curved in the opposite direction to the first track groove portion 9a. The second track groove portion 9a has a second track groove center line Ya. The ball track center line Yb of the track groove portion 9b is smoothly connected. Thus, the ball track center lines Xa and Ya of the first track groove portions 7a and 9a and the ball track center lines Xb and Yb of the second track groove portions 7b and 9b are different in shape.

As shown in FIG. 13, the shape of the first track groove portion 7a of the outer joint member 2 up to the end A on the opening side of the ball track center line Xa is the same as that in the first embodiment. However, the ball track center line Xb of the second track groove portion 7b is different from that of the first embodiment. The center of curvature of the arc-shaped ball track center line Xb of the second track groove portion 7b of the outer joint member 2 of the present embodiment is from a plane M (see FIG. 15) including the ball track center line X of the track groove and the joint center O. It is formed at a position deviated in the circumferential direction (not shown). The first track groove portion 7a is formed with an appropriate curvature so as to be smoothly connected to the end A on the opening side of the ball track center line Xa. The ball track center line Yb of the second track groove portion 9b of the inner joint member 3 shown in FIG. 14 is the same, and the ball track center line Y of the track groove 9 of the inner joint member 3 is the joint at an operating angle of 0 °. relative to the plane P including the center O, are formed in the ball raceway center line X and the mirror image symmetry of the track grooves 7 forming a pair of the outer joint member 2.

  A state where the track groove 7 of the outer joint member 2 is inclined in the circumferential direction with respect to the joint axis NN will be described with reference to FIG. A plane M including the ball track center line Xa of the first track groove 7Aa of the outer joint member 2 and the joint center O is inclined by an angle γ with respect to the joint axis NN. The first track groove portion 7Ba adjacent to the first track groove portion 7Aa in the circumferential direction is omitted from illustration, but the plane M including the ball track center line Xa of the first track groove portion 7Ba and the joint center O is It is inclined by an angle γ in the direction opposite to the inclination direction of the first track groove portion 7Aa with respect to the joint axis NN. As described above, in the present embodiment, only the first track groove portions 7Aa and 7Ba are formed on the plane M. Further, in the present embodiment, the ball track center line Xb of the second track groove portion 7Ab is smoothly connected to the opening side end A of the ball track center line Xa of the first track groove portion 7Aa, and is then opened to the opening side. It is gently curved so that the inclination angle gradually decreases toward the opening, and the inclination angle is 0 ° in the vicinity of the opening end. The ball track center line Xb of the second track groove portion 7Bb having the opposite inclination direction is formed in the same manner.

  A state in which the track groove 9 of the inner joint member 3 is inclined in the circumferential direction with respect to the joint axis NN will be described with reference to FIG. The plane Q including the ball track center line Ya and the joint center O of the first track groove 9Aa of the inner joint member 3 is inclined by an angle γ with respect to the joint axis NN. The first track groove portion 9Ba adjacent to the first track groove portion 9Aa in the circumferential direction is omitted in the drawing, but the plane Q including the ball track center line Ya and the joint center O of the first track groove portion 9Ba is It is inclined by an angle γ in the direction opposite to the inclination direction of the first track groove portion 9Aa with respect to the joint axis NN. Similarly to the track groove of the outer joint member 2 described above, the ball track center line Yb of the second track groove portion 9Ab of the inner joint member 3 is an end portion on the back side of the ball track center line Ya of the first track groove portion 9Aa. After being smoothly connected to B, it is gently curved so that the inclination angle gradually decreases toward the back side, and the inclination angle is 0 ° in the vicinity of the end on the back side. The ball track center line Yb of the second track groove portion 9Bb having the opposite inclination direction is formed in the same manner.

  Since the second track groove portions 7Ab, 9Ab and 7Bb, 9Bb of the outer joint member 2 and the inner joint member 3 are formed as described above, the second track groove portions 7Ab, 7Bb, and 9Ab adjacent in the circumferential direction are formed. The distance on the closer side of 9Bb is increased, and the difference between the distances in the circumferential direction can be reduced. Thereby, the difference in the contact area on the opening side of each spherical inner peripheral surface 6 of the outer joint member 2 and the difference in the contact area on the back side of each spherical outer peripheral surface 8 of the inner joint member 3 can be reduced. The spherical contact portions of the container 5 and the outer joint member 2 and the inner joint member 3 can be arranged in a well-balanced manner, thereby further facilitating the operation.

  In the fifth embodiment, the ball track center line Xb of the second track groove portions 7Ab, 7Bb of the outer joint member 2 is used as the end portion on the opening side of the ball track center line Xa of the first track groove portions 7Aa, 7Ba. After being smoothly connected to A, it is gently curved so that the inclination angle gradually decreases toward the opening side, and is formed so that the inclination angle becomes 0 ° near the opening end, while the inner joint member 3 After smoothly connecting the ball track center line Yb of the second track groove portions 9Ab, 9Bb with the end B on the back side of the ball track center line Ya of the first track groove portions 9Aa, 9Ba, toward the back side Although it is shown that it is gently curved so that the inclination angle gradually decreases and the inclination angle is 0 ° in the vicinity of the back end, the present invention is not limited to this. That is, the ball track center line Xb of the second track groove portions 7Ab and 7Bb of the outer joint member 2 is relatively small in radius at the end A on the opening side of the ball track center line Xa of the first track groove portions 7Aa and 7Ba. After that, the opening side is formed with an inclination angle of 0 °, and the ball track center line Yb of the second track groove portions 9Ab, 9Bb of the inner joint member 3 is similarly connected to the first track groove portions 9Aa, After connecting to the end B on the back side of the 9Ba ball trajectory center line Ya with an arc having a relatively small radius of curvature, the back side may be formed with an inclination angle of 0 °.

  In the fixed type constant velocity universal joint of the above embodiment, the number of the balls 4 has been described as eight. However, the present invention is not limited to this. The number of balls is preferably ten, and a ball having twelve balls can be appropriately implemented.

  In the above-described fixed constant velocity universal joint, the ball track center line Xb of the second track groove portion has been described as having an arc shape, but the present invention is not limited to this. In short, any shape can be used as long as the shape is different from the ball track center line Xa of the first track groove portion and the effective track length can be increased to increase the operating angle. Or a straight line. Further, the first track groove portion and the second track groove portion are not limited to a single arc, but may be formed by a plurality of arcs in consideration of the track groove depth and the like. Further, although the track grooves are arranged at equal pitches in the circumferential direction, they may be arranged at unequal pitches. In addition, although the inclination angle γ of the first track groove with respect to the joint axis NN is the same in all the track grooves, the inclination angle γ is not limited to this, and the inclination angle γ is a pair of the outer joint member and the inner joint member. The first track groove and the other pair of first track grooves may be formed at unequal angles. In short, each inclination angle should be set so that the axial force of the ball acting on all the pockets in the circumferential direction of the cage is balanced as a whole. In addition, although the embodiment of the angular contact in which the track groove and the ball are in contact with each other at a contact angle has been described, the present invention is not limited to this, and a circular contact in which the cross-sectional shape of the track groove is formed in a circular shape may be used.

  The present invention is not limited to the above-described embodiments, and can of course be implemented in various forms without departing from the scope of the present invention. The scope of the present invention is not limited to patents. It includes the equivalent meanings recited in the claims and the equivalents recited in the claims, and all modifications within the scope.

DESCRIPTION OF SYMBOLS 1 Fixed type constant velocity universal joint 2 Outer joint member 3 Inner joint member 4 Ball 5 Cage 6 Spherical inner peripheral surface 7 Track groove 7a First track groove portion 7b Second track groove portion 8 Spherical outer peripheral surface 9 Track groove 9a First Track groove 9b second track groove 11 shaft 12 spherical outer peripheral surface 13 spherical inner peripheral surface 20 drive shaft A end B end C connecting point f1 offset amount f2 offset amount f3 offset amount f4 offset amount K perpendicular L straight line M ball Plane N including the track center line O Joint axis O Joint center P Joint center plane Q Plane including the ball track center line Oo1 Center of curvature Oo2 Center of curvature Oo3 Center of curvature Oo4 Center of curvature R Straight line X Ball track centerline Y Ball track centerline γ Inclination angle β Angle θ Operating angle

Claims (11)

A plurality of track grooves extending in the axial direction are formed on the spherical inner peripheral surface, and an outer joint member having an opening side and a back side that are separated in the axial direction, and a plurality of pairs that form pairs with the track grooves of the outer joint member on the spherical outer peripheral surface An inner joint member in which a track groove is formed, a plurality of balls that are interposed between the track groove of the outer joint member and the track groove of the inner joint member, and transmit the torque; In a fixed type constant velocity universal joint provided with a spherical outer peripheral surface fitted to a spherical inner peripheral surface of the joint member and a spherical outer peripheral surface of the inner joint member, and a cage having a spherical inner peripheral surface,
The track groove of the outer joint member includes a first track groove portion located on the back side and a second track groove portion located on the opening side, and the first track groove portion is offset in the axial direction with respect to the joint center. The first track groove portions adjacent to each other in the circumferential direction are formed opposite to each other in the circumferential direction with respect to the joint axis. The second track groove portion has a shape different from that of the first track groove portion in order to increase an effective track length with respect to a maximum operating angle, and the first track groove portion and the second track groove portion are different from each other. The track groove of the inner joint member is a pair of the outer joint member on the basis of a plane including the joint center in an operating angle of 0 °. Fixed type constant velocity universal joint, characterized in that it is formed in the track groove and mirror image symmetry.   A straight line connecting a point where the first track groove portion and the second track groove portion are connected and the joint center forms an angle (β) with respect to a plane including the joint center when the operating angle is 0 °. The fixed constant velocity universal joint according to claim 1, wherein the fixed constant velocity universal joint is set to 3 ° to 10 °.   The fixed constant velocity universal joint according to claim 1 or 2, wherein a center of curvature of the arc of the first track groove portion is arranged on an axis of the joint.   The fixed constant velocity universal joint according to claim 1 or 2, wherein a center of curvature of the arc of the first track groove portion is offset in a radial direction from an axis of the joint.   2. The fixed constant velocity universal joint according to claim 1, wherein the spherical outer peripheral surface and the spherical inner peripheral surface of the cage have a center of curvature offset in the axial direction with respect to the joint center (O). .   The fixed constant velocity universal joint according to claim 1, wherein the second track groove portion includes an arc-shaped portion.   The said 2nd track groove part consists of an arc-shaped part and a linear part, and this linear part is smoothly connected to the said 1st track groove part, The any one of Claims 1-6 characterized by the above-mentioned. The fixed type constant velocity universal joint according to one item.   The arc-shaped portion of the second track groove portion has a center of curvature that is radially outward from the first track groove portion and offset toward the opening side from the joint center. A fixed type constant velocity universal joint according to claim 1.   The fixed constant velocity universal joint according to any one of claims 1 to 8, wherein an inclination angle in a circumferential direction of the second track groove portion gradually decreases toward the opening side.   The fixed constant velocity universal joint according to any one of claims 1 to 9, wherein the second track groove portion has a portion that is not inclined with respect to the axis of the joint.   The fixed type constant velocity universal joint according to any one of claims 1 to 10, wherein the number of the torque transmission balls is eight.

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