JP2010019275A - Ball-type constant velocity joint - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a ball-type constant velocity joint capable of miniaturizing a whole joint and reducing the weight by lessening the maximum load generated between a ball and a retainer. <P>SOLUTION: A center locus C1 of a ball 40 rolling on an outer ring ball groove 23 is formed in an S shape curving circumferentially from one end to the other end of the outer ring ball groove 23 viewed radially and outwardly from an axis line of an outer ring 20. A center locus C2 of the ball 40 rolling on an inner ring ball groove 32 is formed in an S shape curving circumferentially from one end to the other end of an inner ring ball groove 32 viewed from a radially outer side to the axis line of the inner ring 30. When the ball 40 is positioned at a deeper side than the outer ring 20, a difference between a pitch circle radius of the outer ring ball groove 23 and a pitch circle radius of the inner ring ball groove 32 at a portion where the ball 40 is positioned is set greater than a difference at the portion where the ball 40 is positioned at a central position A. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a ball type constant velocity joint.

  Examples of the ball-type constant velocity joint include those described in Japanese Patent Application Laid-Open No. 2003-194089 (Patent Document 1) and Japanese Patent Application Laid-Open No. 2001-153149 (Patent Document 2). In the general ball type constant velocity joints described in these patent documents, the ball trajectories in the outer ring ball groove and the inner ring ball groove are set parallel to the circumferential direction with respect to the rotation axis. That is, each ball trajectory is set to be located on the same plane passing through the rotation axis.

Patent Documents 3 and 4 disclose that the ball trajectory in the inner ring ball groove is not set parallel to the circumferential direction with respect to the rotation axis.
JP 2003-194089 A JP 2001-153149 A JP-A-10-252769 Japanese Patent Laid-Open No. 11-236927

  In the ball-type constant velocity joint described in Patent Document 1 or the like, only a small load and a ball that receives a large load due to the rotational phase of the joint are received between the ball groove and the ball groove when torque is transmitted with the joint angle taken. There may be balls. The load received by the ball at this time is also applied to the cage that holds the ball. And the strength of the outer ring, inner ring and cage must be ensured corresponding to the ball receiving the maximum load. By the way, in the current strength balance of each member, the breaking strength of the cage may be the weakest. In such a case, if the maximum load of the cage received from the ball is reduced, the breaking strength of the cage is improved. As a result, the entire joint can be reduced in size and weight.

  Further, if it is attempted to ensure a large maximum joint angle, it is difficult to ensure the ball track length of the ball groove of the outer ring. In the invention described in the cited document 2, an attempt is made to widen the maximum joint angle by making the opening of the outer ring into a tapered shape that is linearly expanded. However, the shape of the outer ring causes a decrease in strength. There is a fear. Patent Documents 3 and 4 do not describe anything related to the load that the ball receives.

  The present invention has been made in view of such circumstances, and an object thereof is to provide a ball-type constant velocity joint that can be reduced in size and weight as a whole joint.

  Hereinafter, each means suitable for solving the above-described problems will be described with additional effects and the like as necessary.

1. Ball type constant velocity joint
An outer ring having a cylindrical shape with an opening in one axial direction and having a plurality of outer ring ball grooves formed on the inner peripheral surface;
An inner ring disposed inside the outer ring and having a plurality of inner ring ball grooves formed on the outer peripheral surface;
A plurality of balls that roll on each of the outer ring ball groove and the inner ring ball groove to transmit torque between the outer ring and the inner ring;
A cage formed of an annular shape, disposed between the outer ring and the inner ring, and formed with a plurality of windows that respectively accommodate the balls in the circumferential direction;
In a ball-type constant velocity joint comprising
The center locus of the ball when rolling the outer ring ball groove is located on the opening side of the outer ring ball groove when the outer ring ball groove is viewed from the axial center of the outer ring toward the radially outer side. A first curved portion that curves in the circumferential direction, and a second curved portion that is located on the opposite side of the opening of the outer ring ball groove and curves in the circumferential direction opposite to the first curved portion. S-shaped,
When the inner ring ball groove rolls, the center locus of the ball is located on the opening side of the inner ring ball groove when the inner ring ball groove is viewed from the radially outer side of the inner ring toward the axis. A third curved portion that curves in the circumferential direction, and a fourth curved portion that is located on the opposite side to the opening of the inner ring ball groove and curves in the circumferential direction opposite to the third curved portion. S-shaped,
The opening side of the first curved portion of the outer ring ball groove and the opening side of the third curved portion of the inner ring ball groove in a state where the inner ring is disposed inside the outer ring are opposite in the circumferential direction. Facing the direction, and
When the ball is located on the opposite side of the opening of the outer ring, the difference between the pitch circle radius of the outer ring ball groove and the pitch circle radius of the inner ring ball groove at the position where the ball is located is determined by the joint angle. In the case of 0 deg, it is set larger than the difference in the part where the ball is located.

  In the means 1, the ball center locus when rolling in each outer ring ball groove is set not to be located on the same plane passing through the rotation axis of the outer ring, but to be deviated in an S shape from the plane. . Further, the ball center locus when rolling in each inner ring ball groove is set not to be located on the same plane passing through the rotation axis of the inner ring, but to be shifted from the plane shape to an S shape.

  Then, in the means 1, when the ball is located on the opposite side of the opening of the outer ring, the pitch circle radius of the outer ring ball groove and the pitch circle radius of the inner ring ball groove at the position where the ball is located. The difference is set to be larger than the difference at the portion where the ball is located at the central position.

  Here, the pitch circle radius of the outer ring ball groove is the radius of the center locus of the ball when rolling the outer ring ball groove, that is, the distance from the rotation axis of the outer ring to the center locus of the ball. The pitch circle radius of the inner ring ball groove is the radius of the center locus of the ball when rolling the inner ring ball groove, that is, the distance from the rotation axis of the inner ring to the center locus of the ball.

  When the pitch circle radius difference between the outer ring ball groove and the inner ring ball groove is increased, the gap between the ball and the ball groove is increased. According to this means, the pitch circle radius difference when the ball is positioned on the side opposite to the opening of the outer ring is set larger than the pitch circle radius difference when the joint angle is 0 deg. That is, the gap between the ball and the ball groove is set larger when the ball is positioned on the side opposite to the opening than when the ball is positioned at the joint angle of 0 deg.

  Therefore, according to the means 1, the center locus of the ball when rolling the outer ring ball groove and the center locus of the ball when rolling the inner ring ball groove are formed in the S shape as described above, and By increasing the gap between the ball and the ball groove on the side opposite to the opening of the outer ring, the ball is less likely to hit the ball groove. As a result, the load on the cage when the ball is located in the ball groove is reduced. Can be reduced.

  That is, when torque is transmitted from the inner ring to the outer ring and the joint rotates toward the opening side of the S-shaped first curved portion, the maximum load that the ball receives with the cage can be reduced. As a result, the strength of the cage with the weakest strength can be adjusted to the maximum load. Therefore, in the case of a ball-type constant velocity joint with the same performance and capacity, this means can be used to reduce the size. It is possible to reduce the weight. The difference in pitch circle radius can be increased by increasing the pitch circle radius of the outer ring ball groove or decreasing the pitch circle radius of the inner ring ball groove.

  Further, according to the means 1, the contact point between the ball and the ball groove that is closest to the opening of the outer ring ball groove in the state where the joint angle is maximized is such that the ball locus is in the circumferential direction with respect to the rotation axis. In the case of a ball-type constant velocity joint with the same performance and capacity, it can be inside the outer ring (on the side opposite to the opening) than the conventional ball-type constant velocity joint set parallel to By adopting this means, it is possible to reduce the size and weight. Moreover, if it is the same size as the past, the maximum joint angle can be expanded.

  In the means 1, the first curved portion is formed from an end of the outer ring ball groove on the opening side to a central position where the center of the ball is located at a joint angle of 0 deg. The second curved portion is formed from the central position to the end of the outer ring ball groove opposite to the opening, and the third curved portion is located on the opening side of the inner ring ball groove. It is desirable that the fourth curved portion is formed from the end portion to the central position, and the fourth curved portion is formed from the central position to the end portion on the opposite side to the opening of the inner ring ball groove. .

  2. In the ball type constant velocity joint described in means 1, the difference is set to be constant from a state where the ball is positioned on the opening side of the outer ring to a state where the joint angle is 0 deg.

  According to the means 2, the gap between the ball and the ball groove is constant between the state where the ball is located on the opening side of the outer ring and the state where the joint angle is 0 deg. Thereby, the maximum load which a ball receives can be reduced reliably.

  3. In the ball type constant velocity joint described in means 1 or 2, the opening side of the first curved portion is oriented in the main rotation direction when torque is transmitted from the inner ring to the outer ring.

  As described above, according to the above means, when torque is transmitted from the inner ring to the outer ring, and when the joint rotates to the opening side of the S-shaped first bending portion, Can reduce the maximum load that the ball receives. Therefore, when the ball-type constant velocity joint is applied to a portion where torque is transmitted from the inner ring to the outer ring and is rotated in both directions, according to this means, the main rotation direction of the rotation direction is the S-shaped first. It sets so that it may face the opening side of one curved part. Thus, the maximum load that the ball receives with the cage can be reliably reduced in the main rotation direction when torque is transmitted from the inner ring to the outer ring. For example, when the ball type constant velocity joint of the present invention is applied to a drive shaft or propeller shaft of a vehicle, the direction of rotation when the vehicle moves forward is set as the main rotation direction.

  4). In the ball-type constant velocity joint according to means 3, the second contact angle between the outer ring ball groove and the ball on the opposite side to the main rotation direction when torque is transmitted from the inner ring to the outer ring is the main contact angle. It is set smaller than the first contact angle between the outer ring ball groove and the ball on the rotation direction side.

  Here, the “contact angle between the outer ring ball groove and the ball” means a plane passing through the axis of the outer ring and the center of the ball, and a straight line connecting the contact point of the outer ring ball groove with the ball and the center of the ball, Is an acute angle. That is, the smaller the contact angle, the shorter the distance from the plane passing through the outer ring axis and the center of the ball to the contact point of the outer ring ball groove.

  As described above, since the ball center locus of the outer ring ball groove is formed in an S shape in the circumferential direction, it is assumed that the first contact angle between the outer ring ball groove and the ball on the main rotation direction side and vice versa. If the second contact angle between the outer ring ball groove and the ball on the side is the same, there is a possibility that the contact point between the ball and the outer ring ball groove cannot be secured when rotating in the direction opposite to the main rotation direction. In this case, the ball comes into contact with the end portion (edge portion) of the outer ring ball groove, and there is a possibility that the ball rolls smoothly and hinders smooth load transmission by the ball. As a result, the ball or the outer ring ball groove may be damaged.

  Therefore, according to this means, when the torque is transmitted from the inner ring to the outer ring, the second contact angle between the outer ring ball groove and the ball on the side opposite to the main rotation direction is equal to the outer ring ball groove and the ball on the main rotation direction side. Is set smaller than the first contact angle. That is, the contact point on the opposite side of the main rotation direction is brought close to the center line so as to secure the contact point between the outer ring ball groove and the ball. This prevents the ball from coming into contact with the end of the outer ring ball groove.

  5. In the ball-type constant velocity joint according to Means 3 or 4, when a torque is transmitted from the inner ring to the outer ring, a fourth contact angle between the inner ring ball groove on the main rotation direction side and the ball is It is set smaller than the third contact angle between the inner ring ball groove and the ball on the opposite side to the main rotation direction.

  The means 4 is for the contact angle between the outer ring ball groove and the ball, but the same can be said for the contact angle between the inner ring ball groove and the ball. Here, the “contact angle between the inner ring ball groove and the ball” means a plane passing through the center of the inner ring and the center of the ball, and a straight line connecting the contact point with the ball in the inner ring ball groove and the center of the ball, Is an acute angle. That is, the smaller the contact angle, the shorter the distance from the plane passing through the center of the inner ring and the center of the ball to the contact point of the inner ring ball groove. Therefore, according to the present means, the contact point on the opposite side of the main rotation direction is brought close to the center line to secure the contact point between the inner ring ball groove and the ball. This prevents the ball from contacting the end of the inner ring ball groove.

  6). In the ball type constant velocity joint described in means 1 or 2, the opening side of the first curved portion is directed to the opposite side of the main rotation direction when torque is transmitted from the outer ring to the inner ring.

  According to the above means, when torque is transmitted from the outer ring to the inner ring, and when the joint rotates in the direction opposite to the opening side of the S-shaped first curved portion, between the cage and the cage The maximum load that the ball receives can be reduced. Therefore, when the ball-type constant velocity joint is applied to a portion where torque is transmitted from the outer ring to the inner ring and is rotated in both directions, according to this means, the opposite side of the main rotation direction among the rotation directions is S-shaped. The first curved portion is set so as to face the opening side. Thereby, it is possible to reduce the maximum load that the ball receives with the cage in the main rotation direction even when torque is transmitted from the outer ring to the inner ring. For example, when the ball type constant velocity joint of the present invention is applied to a drive shaft or propeller shaft of a vehicle, the direction of rotation when the vehicle moves forward is set as the main rotation direction.

  7). In the ball-type constant velocity joint of the means 6, when a torque is transmitted from the outer ring to the inner ring, a second contact angle between the outer ring ball groove on the main rotation direction side and the ball is set in the main rotation direction. It is set smaller than the first contact angle between the outer ring ball groove and the ball on the opposite side.

  As described above, since the ball center locus of the outer ring ball groove is formed in an S shape in the circumferential direction, the first contact angle between the outer ring ball groove and the ball on the main rotation direction side and the opposite side are assumed. If the second contact angle between the outer ring ball groove and the ball is the same, the contact point between the ball and the outer ring ball groove may not be secured when rotating in the direction opposite to the main rotation direction. In this case, the ball comes into contact with the end portion (edge portion) of the outer ring ball groove, and there is a possibility that the ball rolls smoothly and hinders smooth load transmission by the ball. As a result, the ball or the outer ring ball groove may be damaged.

  Therefore, according to this means, when the torque is transmitted from the outer ring to the inner ring, the second contact angle between the outer ring ball groove and the ball on the main rotation direction side is the outer ring ball groove and ball on the opposite side of the main rotation direction. Is set smaller than the first contact angle. That is, the contact point on the main rotation direction side is brought close to the center line so as to secure the contact point between the outer ring ball groove and the ball. This prevents the ball from coming into contact with the end of the outer ring ball groove.

  8). In the ball type constant velocity joint of means 6 or 7, the fourth contact angle between the inner ring ball groove and the ball on the opposite side to the main rotation direction when torque is transmitted from the outer ring to the inner ring is It is set smaller than the third contact angle between the inner ring ball groove and the ball on the main rotation direction side.

  The means 7 is for the contact angle between the outer ring ball groove and the ball, but the same can be said for the contact angle between the inner ring ball groove and the ball. That is, according to the present means, the contact point on the main rotation direction side is brought close to the center line so as to ensure the contact point between the inner ring ball groove and the ball. This prevents the ball from contacting the end of the inner ring ball groove.

  Hereinafter, an embodiment in which the ball type constant velocity joint of the present invention is embodied will be described with reference to the drawings.

  A configuration of the ball type constant velocity joint 10 (hereinafter, simply referred to as “constant velocity joint”) of the present embodiment will be described with reference to FIG. FIG. 1 is an axial sectional view of a constant velocity joint 10. In the following description, the opening side of the outer ring 20 means the left side of FIG. 1, and the back side of the outer ring 20 means the right side of FIG. Moreover, the constant velocity joint 10 of this embodiment demonstrates the case where it applies to the outboard constant velocity joint of the drive shaft of a vehicle, ie, the constant velocity joint which transmits a torque from the inner ring | wheel 30 to the outer ring | wheel 20.

  As shown in FIG. 1, the constant velocity joint 10 includes a fixed ball type constant velocity joint (also referred to as a “Zepper type constant velocity joint”). The constant velocity joint 10 includes an outer ring 20, an inner ring 30, a plurality of balls 40, and a cage 50. Hereinafter, each component will be described in detail.

  The outer ring 20 has a cup shape (bottomed cylindrical shape) having an opening on the left side in FIG. Another power transmission shaft (not shown) is coaxially connected to the cup bottom 21 of the outer ring 20. Furthermore, the inner peripheral surface of the outer ring 20 is formed in a spherical concave shape. Specifically, the spherical concave inner peripheral surface 22 of the outer ring 20 is formed in an arc concave shape when viewed in a cross section cut in the outer ring axial direction.

  Furthermore, a plurality of outer ring ball grooves 23 whose outer ring axis orthogonal cross section is substantially arc-shaped are formed on the inner peripheral surface of the outer ring 20 so as to extend substantially in the outer ring axis direction. Details of the outer ring ball groove 23 will be described later. The plurality of (six in this embodiment) outer ring ball grooves 23 are formed at equal intervals in the circumferential direction (60-degree intervals in this embodiment) when viewed in a cross section cut in the radial direction. Here, the outer ring axial direction means a direction passing through the central axis of the outer ring 20, that is, a rotation axis direction of the outer ring 20.

  The inner ring 30 has an annular shape and is disposed inside the outer ring 20. The outer peripheral surface of the inner ring 30 is formed in a spherical convex shape. Specifically, the spherical convex outer peripheral surface 31 of the inner ring 30 is formed in a uniform arc, that is, a convex partial spherical shape when viewed in a cross section cut in the inner ring axial direction.

  Furthermore, a plurality of inner ring ball grooves 32 whose inner ring axis orthogonal cross section is substantially arc-shaped are formed on the outer peripheral surface of the inner ring 30 so as to extend substantially in the inner ring axis direction. Details of the inner ring ball groove 32 will be described later. These multiple (six in this embodiment) inner ring ball grooves 32 are equally spaced in the circumferential direction (60 degrees in the present embodiment) and viewed from the outer ring 20 when viewed in a cross section cut in the radial direction. The same number of outer ring ball grooves 23 are formed. That is, each inner ring ball groove 32 is positioned so as to face each outer ring ball groove 23 of the outer ring 20.

  Further, an inner peripheral spline 33 extending in the inner ring axial direction is formed on the inner peripheral surface of the inner ring 30. The inner peripheral spline 33 is fitted (engaged) with the outer peripheral spline of the power transmission shaft 35. Here, the inner ring axial direction means a direction passing through the central axis of the inner ring 30, that is, a rotation axis direction of the inner ring 30.

  Each of the plurality of balls 40 is disposed so as to be sandwiched between the outer ring ball groove 23 of the outer ring 20 and the inner ring ball groove 32 of the inner ring 30 facing the outer ring ball groove 23. Each ball 40 is rotatable with respect to each outer ring ball groove 23 and each inner ring ball groove 32 and is engaged in a circumferential direction (around the outer ring axis or around the inner ring axis). Therefore, the ball 40 transmits torque between the outer ring 20 and the inner ring 30.

  The cage 50 has an annular shape. The outer peripheral surface 51 of the cage 50 is formed in a partial spherical shape substantially corresponding to the spherical concave inner peripheral surface 22 of the outer ring 20, that is, a spherical convex shape. On the other hand, the inner peripheral surface 52 of the cage 50 is formed in a partial spherical shape substantially corresponding to the spherical convex outer peripheral surface 31 of the inner ring 30, that is, a spherical concave shape. The cage 50 is disposed between the spherical concave inner peripheral surface 22 of the outer ring 20 and the spherical convex outer peripheral surface 31 of the inner ring 30. Furthermore, the cage 50 has a plurality of window portions 53 that are substantially rectangular through holes formed at equal intervals in the circumferential direction (the circumferential direction of the cage axis). The same number of the window portions 53 as the balls 40 are formed. One ball 40 is accommodated in each window 53.

  Next, the detailed shape of the outer ring ball groove 23 will be described with reference to FIGS. FIG. 2 is an axial sectional view of the outer ring 20. FIG. 3 is a view of the outer ring ball groove 23, the inner ring ball groove 32, and the ball 40 viewed from the axial direction.

  As shown in FIG. 2, the center locus C1 of the ball 40 when rolling the outer ring ball groove 23 is the outer ring ball groove 23 when the outer ring ball groove 23 is viewed from the axial center of the outer ring 20 toward the radially outer side. A first curved portion that curves in the circumferential direction from an end portion on the opening portion side of 23 to a central position A where the center of the ball is located when the joint angle is 0 deg, and an opening of the outer ring ball groove 23 from the central position A The first curved portion and the second curved portion curved in the circumferential direction on the opposite side are formed to the opposite end (back side) to the end portion. That is, the center locus C1 of the ball 40 in each outer ring ball groove 23 is set so as to deviate from the same plane passing through the axis of the outer ring 20. More specifically, when the outer ring ball groove 23 is viewed from the opening side of the outer ring 20 (left side in FIG. 2), the opening side of the first curved part faces in the counterclockwise direction. Here, the “counterclockwise direction” refers to the direction of rotation when the vehicle moves forward, that is, this direction is the main direction of rotation when the vehicle is in use.

  The S-shaped center locus C1 in the outer ring ball groove 23 is set so that the center of the ball 40 is located at the center position A when the joint angle is 0 deg. Furthermore, in the S-shaped central locus C1, the behavior at the first curved portion on the opening side, and in the S-shaped central locus C1, the second curved portion on the opposite side (back side) from the opening portion. Is set symmetrically with respect to the center position A. However, these behaviors are not always set symmetrically, and are adjusted as appropriate. Furthermore, as shown in FIG. 3, the second contact angle θ2 between the outer ring ball groove 23 and the ball 40 on the side opposite to the main rotation direction (reverse direction of the vehicle) is on the main rotation direction side (vehicle advance direction). It is set smaller than the first contact angle θ 1 between the outer ring ball groove 23 and the ball 40.

  Here, the “contact angle between the outer ring ball groove 23 and the ball 40” refers to a plane passing through the axis of the outer ring 20 and the center of the ball 40, and contact points P 1 and P 2 of the outer ring ball groove 23 with the ball 40. An acute angle formed by a straight line connecting the center of the ball 40. That is, the smaller the contact angle, the shorter the distance from the plane passing through the axis of the outer ring 20 and the center of the ball 40 to the contact point of the outer ring ball groove 23. The contact point P1 is a contact point between the outer ring ball groove 23 and the ball 40 on the main rotation direction side (vehicle forward direction), and the contact point P2 is on the opposite side (vehicle reverse direction) to the main rotation direction. This is a contact point between the outer ring ball groove 23 and the ball 40.

  Next, the detailed shape of the inner ring ball groove 32 will be described with reference to FIGS. FIG. 4 is a view of the inner ring 30 as viewed from the radial direction.

  As shown in FIG. 4, the center locus C2 of the ball 40 when rolling the inner ring ball groove 32 is the inner ring ball groove when the inner ring ball groove 32 is viewed from the radially outer side of the inner ring 30 toward the axis. 32 from the end on the opening side to the center position A, and from the center position A to the end on the side opposite to the opening of the inner ring ball groove 32 (back side). The third bending portion and the fourth bending portion that curves in the opposite circumferential direction are formed in an S shape. That is, the center locus C2 of the ball 40 in each inner ring ball groove 32 is set so as to deviate from the same plane passing through the axis of the inner ring 30. More specifically, when the inner ring 30 is disposed on the inner side of the outer ring 20, when the inner ring ball groove 32 is viewed from the opening side (the left side in FIG. 1) of the outer ring 20, the opening side of the fourth curved portion is opposite. It faces clockwise. That is, in the state where the inner ring 30 is disposed inside the outer ring 20, the opening side of the first bending portion in the outer ring ball groove 23 and the opening side of the fourth bending portion in the inner ring ball groove 32 are the same in the circumferential direction. Suitable for. Further, the opening side of the second curved portion in the outer ring ball groove 23 and the opening side of the third curved portion in the inner ring ball groove 32 are oriented in the same circumferential direction.

  The S-shaped center locus C2 in the inner ring ball groove 32 is set so that the center of the ball 40 is located at the center position A when the joint angle is 0 deg. Further, the behavior of the S-shaped central locus C2 at the third curved portion on the opening side and the S-shaped central locus C2 of the fourth curved portion on the opposite side (back side) from the opening portion. Is set symmetrically with respect to the center position A. However, these behaviors are not always set symmetrically, and are adjusted as appropriate. Further, as shown in FIG. 3, the fourth contact angle θ4 between the inner ring ball groove 32 and the ball 40 on the side opposite to the main rotation direction (reverse direction of the vehicle) is on the main rotation direction side (vehicle advance direction). It is set smaller than the third contact angle θ3 between the inner ring ball groove 32 and the ball 40.

  Here, the “contact angle between the inner ring ball groove 32 and the ball 40” refers to a plane passing through the axis of the inner ring 30 and the center of the ball 40, and contact points P 3 and P 4 of the inner ring ball groove 32 with the ball 40. An acute angle formed by a straight line connecting the center of the ball 40. That is, the smaller the contact angle, the shorter the distance from the plane passing through the axis of the inner ring 30 and the center of the ball 40 to the contact point of the inner ring ball groove 32. The contact point P3 is a contact point between the inner ring ball groove 32 and the ball 40 on the main rotation direction side (vehicle forward direction), and the contact point P4 is on the opposite side (vehicle reverse direction) to the main rotation direction. This is a contact point between the inner ring ball groove 32 and the ball 40.

  Further, the difference between the pitch circle radius of the outer ring ball groove 23 and the pitch circle radius of the inner ring ball groove 32 will be described with reference to FIG. FIG. 5 is a diagram showing the relationship of the pitch circle radius difference with respect to the position of the ball 40 in a certain outer ring ball groove 23 and inner ring ball groove 32.

  As shown in FIG. 5, the pitch circle radius difference is set to be constant between the state where the ball 40 is positioned on the opening side of the outer ring ball groove 23 and the state where the joint angle is 0 deg. Then, the pitch circle radius difference is set so as to gradually increase from the state where the ball 40 is at the joint angle of 0 deg toward the state where the ball 40 is located on the innermost side of the outer ring ball groove 23. That is, when the ball 40 is located on the back side of the outer ring 20, the difference between the pitch circle radius of the outer ring ball groove 23 and the pitch circle radius of the inner ring ball groove 32 in the portion where the ball 40 is located is the joint angle 0 deg. In this case, it is set to be larger than the pitch circle radius difference at the portion (center position A) where the ball 40 is located.

  This configuration can be achieved by forming the outer ring ball groove 23 so that the pitch circle radius increases from the center position A toward the inner side of the outer ring 20. In addition, it can be achieved by forming the pitch circle radius of the inner ring ball groove 32 so as to decrease from the central position A toward the opening side of the outer ring 20. Furthermore, the outer ring ball groove 23 and the inner ring ball groove 32 may be configured as described above. If the pitch circle radius difference is increased, the gap between the ball 40 and the ball grooves 23 and 32 is increased.

  About the constant velocity joint 10 of this embodiment mentioned above, the contact load produced between the holder | retainer 50 and the ball | bowl 40 was analyzed. As Comparative Example 1, a conventional one in which the outer ring ball groove 23 was formed in parallel with the outer ring axis direction and the inner ring ball groove 32 was formed in parallel with the inner ring axis direction was performed. Further, as Comparative Example 2, the same difference as that of Comparative Example 1 was performed except that the shapes of the outer ring ball groove 23 and the inner ring ball groove 32 were changed to an S shape.

  The analysis results are shown in FIG. FIG. 6 is an analysis result showing “contact load generated between the cage 50 and the ball 40” according to the rotation phase of the constant velocity joint 10. In FIG. 6, the analysis results of Comparative Example 1 are indicated by white circles and thin solid lines, the analysis results of Comparative Example 2 are indicated by white triangles and thin broken lines, and the analysis results of the embodiment are indicated by black circles and thick solid lines. Show.

  Here, the rotational phase of the constant velocity joint 10 will be described with reference to FIG. FIG. 7 is a view of the constant velocity joint 10 as seen from the opening side in the axial direction of the outer ring 20 in a state where the joint angle is taken. As shown in FIG. 7, when the shaft connected to the inner ring 30 is bent downward in FIG. 7, the upper end position is set to the rotation phase 0 deg, and the rotation phase is rotated counterclockwise in FIG. 7. Define to progress. Note that the counterclockwise direction in FIG. 7 corresponds to the rotation direction when the vehicle described above moves forward.

  As shown in FIG. 6, in Comparative Example 1, when the ball 40 is positioned near the rotation phase 0 deg and 200 deg, the contact load between the cage 50 and the ball 40 is larger than in other rotation phases. It is getting bigger. And in the case of the comparative example 1, the contact load becomes the maximum in the rotation phase 200deg vicinity.

  On the other hand, in the case of Comparative Example 2, the contact load in the vicinity of the rotational phase 0 deg and in the vicinity of 200 deg is reduced as compared with Comparative Example 1. However, the contact load in the vicinity of the rotational phase 150 deg increases to approximately the same level as the contact load in the vicinity of the rotational phase 200 deg. Therefore, as a whole, the maximum contact load in Comparative Example 2 is slightly reduced as compared with Comparative Example 1.

  On the other hand, in the case of the embodiment, the contact load in the vicinity of the rotational phase of 0 deg and in the vicinity of 200 deg is significantly reduced as compared with Comparative Example 1. In the case of the embodiment, although the contact load in the vicinity of the rotational phase 60 deg is increased as compared with Comparative Examples 1 and 2, the maximum contact load in the vicinity of the rotational phase 200 deg of the embodiment and the rotation in Comparative Example 2 are used. It does not exceed the maximum contact load near the phase of 150 deg. That is, in the case of the embodiment, it can be seen that the maximum contact load is greatly reduced as compared with Comparative Examples 1 and 2 as a whole.

  As is clear from the above analysis results, the outer ring ball groove 23 and the inner ring ball groove 32 are formed in the S-shape as described above, and the ball groove 23 on the opposite side (back side) from the opening of the outer ring 20. , 32 and the ball 40 can be increased to reduce the maximum contact load generated between the cage 50 and the ball 40. Thereby, since the intensity | strength of the holder | retainer 50 whose intensity | strength is the weakest among each member of the constant velocity joint 10 can be match | combined with the said maximum contact load, it can reduce in size and weight as the whole joint.

  Further, as described above, since the central locus C1 of the ball 40 in the outer ring ball groove 23 and the central locus C2 of the ball 40 in the inner ring ball groove 32 are formed in an S shape, the ball groove 23 in the main rotation direction is temporarily assumed. When the contact angles θ1, θ3 between the ball 32 and the ball 40 and the contact angles θ2, θ4 between the ball grooves 23, 32 and the ball 40 in the opposite direction are the same, the rotation angle is opposite to the main rotation direction. There is a possibility that a contact point between the ball 40 and the ball grooves 23 and 32 cannot be secured.

  In this case, the ball 40 may come into contact with the end portions (edge portions) of the ball grooves 23 and 32, and the ball 40 may roll smoothly and hinder smooth load transmission by the ball 40. As a result, the ball 40 and the ball grooves 23 and 32 may be damaged. Therefore, the contact angles θ2 and θ4 between the ball grooves 23 and 32 and the ball 40 on the side opposite to the main rotation direction (retraction direction) are the contact angles between the ball grooves 23 and 32 and the ball 40 on the main rotation direction side (forward movement direction). It is set smaller than the angles θ1 and θ3. That is, the contact point on the side opposite to the main rotation direction is brought close to the center line so as to secure the contact point between the ball grooves 23 and 32 and the ball 40. This prevents the ball 40 from contacting the end portions of the ball grooves 23 and 32 when the vehicle moves backward.

  In the above embodiment, the case where the present invention is applied mainly to an outboard constant velocity joint of a vehicle drive shaft, for example, that transmits torque from the inner ring 30 to the outer ring 20 has been described. It is also possible to apply the present invention to a constant velocity joint for transmitting the power, that is, an inboard constant velocity joint. When applied to an inboard constant velocity joint, the opening side of the first curved portion of the S-shaped center locus C1 in the outer ring ball groove 23 and the fourth curve of the S-shaped center locus C2 in the inner ring ball groove 32 are used. The opening side of the part should face the opposite side of the main direction of rotation. Further, the second contact angle θ2 between the outer ring ball groove 23 and the ball 40 on the main rotation direction side is set to be smaller than the first contact angle θ1 between the outer ring ball groove 23 and the ball 40 on the opposite side of the main rotation direction. Should. Furthermore, the fourth contact angle θ4 between the inner ring ball groove 32 and the ball 40 on the side opposite to the main rotation direction is set smaller than the third contact angle θ3 between the inner ring ball groove 32 and the ball 40 on the main rotation direction side. Should.

2 is an axial sectional view of the constant velocity joint 10. FIG. 3 is an axial sectional view of the outer ring 20. FIG. It is the figure which looked at the part of the outer ring ball groove 23, the inner ring ball groove 32, and the ball 40 from the axial direction. It is the figure which looked at the inner ring | wheel 30 from radial direction. FIG. 6 is a diagram showing the relationship of the pitch circle radius difference with respect to the position of a ball 40 in a certain outer ring ball groove 23 and inner ring ball groove 32. It is an analysis result showing “contact load generated between the cage 50 and the ball 40” according to the rotational phase of the constant velocity joint 10. It is the figure which looked at the constant velocity joint 10 from the opening part side among the axial directions of the outer ring | wheel 20 in the state which took the joint angle.

Explanation of symbols

10: Ball type constant velocity joint 20: Outer ring, 21: Connecting shaft, 22: Spherical concave inner peripheral surface, 23: Outer ring ball groove 30: Inner ring, 31: Spherical convex outer peripheral surface, 32: Inner ring ball groove, 33: Inner Circumferential spline 40: Ball, 50: Cage, 53: Window

Claims (9)

An outer ring having a cylindrical shape with an opening in one axial direction and having a plurality of outer ring ball grooves formed on the inner peripheral surface;
An inner ring disposed inside the outer ring and having a plurality of inner ring ball grooves formed on the outer peripheral surface;
A plurality of balls that roll on each of the outer ring ball groove and the inner ring ball groove to transmit torque between the outer ring and the inner ring;
A cage formed of an annular shape, disposed between the outer ring and the inner ring, and formed with a plurality of windows that respectively accommodate the balls in the circumferential direction;
In a ball-type constant velocity joint comprising
The center locus of the ball when rolling the outer ring ball groove is located on the opening side of the outer ring ball groove when the outer ring ball groove is viewed from the axial center of the outer ring toward the radially outer side. A first curved portion that curves in the circumferential direction, and a second curved portion that is located on the opposite side to the opening of the outer ring ball groove and curves in the circumferential direction opposite to the first curved portion. S-shaped,
The center locus of the ball when rolling the inner ring ball groove is located on the opening side of the inner ring ball groove when the inner ring ball groove is viewed from the radially outer side of the inner ring toward the axis. A third curved portion that curves in the circumferential direction, and a fourth curved portion that is located on the opposite side of the opening of the inner ring ball groove and curves in the circumferential direction opposite to the third curved portion. S-shaped,
The opening side of the first curved portion of the outer ring ball groove and the opening side of the third curved portion of the inner ring ball groove in a state where the inner ring is disposed inside the outer ring are opposite in the circumferential direction. Facing the direction, and
When the ball is located on the opposite side of the opening of the outer ring, the difference between the pitch circle radius of the outer ring ball groove and the pitch circle radius of the inner ring ball groove at the position where the ball is located is determined by the joint angle. A ball-type constant velocity joint, characterized in that it is set to be larger than the difference in the position where the ball is located at 0 deg. The first curved portion is formed from an end portion on the opening side of the outer ring ball groove to a central position where the center of the ball is located at a joint angle of 0 deg.
The second curved portion is formed from the central position to the end of the outer ring ball groove opposite to the opening,
The third curved portion is formed from an end portion on the opening side of the inner ring ball groove to the central position,
2. The ball-type constant velocity joint according to claim 1, wherein the fourth curved portion is formed from the center position to an end of the inner ring ball groove opposite to the opening.   3. The ball type constant velocity joint according to claim 1, wherein the difference is set constant from a state where the ball is positioned on the opening side of the outer ring to a state where the joint angle is 0 deg.   The ball-type constant velocity joint according to any one of claims 1 to 3, wherein an opening side of the first curved portion is directed in a main rotation direction when torque is transmitted from the inner ring to the outer ring.   When torque is transmitted from the inner ring to the outer ring, a second contact angle between the outer ring ball groove and the ball on the opposite side to the main rotation direction is the outer ring ball groove and the ball on the main rotation direction side. The ball type constant velocity joint according to claim 4, wherein the ball type constant velocity joint is set smaller than the first contact angle.   When torque is transmitted from the inner ring to the outer ring, a fourth contact angle between the inner ring ball groove and the ball on the main rotation direction side is the inner ring ball groove and the ball on the opposite side to the main rotation direction. The ball-type constant velocity joint according to claim 4, wherein the ball-type constant velocity joint is set to be smaller than a third contact angle.   The ball type according to any one of claims 1 to 3, wherein an opening side of the first curved portion is directed to a side opposite to a main rotation direction when torque is transmitted from the outer ring to the inner ring. Fast joint.   When torque is transmitted from the outer ring to the inner ring, the second contact angle between the outer ring ball groove and the ball on the main rotation direction side is the outer ring ball groove and the ball on the opposite side of the main rotation direction. The ball-type constant velocity joint according to claim 7, wherein the ball-type constant velocity joint is set to be smaller than a first contact angle.   When torque is transmitted from the outer ring to the inner ring, the fourth contact angle between the inner ring ball groove and the ball on the opposite side to the main rotation direction is the inner ring ball groove and the ball on the main rotation direction side. The ball type constant velocity joint according to claim 7 or 8, wherein the ball type constant velocity joint is set to be smaller than a third contact angle.

Images