JP6658319B2 - Fixed constant velocity joint - Google Patents

Description

  The present invention relates to a fixed type constant velocity joint that is used by being connected to, for example, a drive shaft of a vehicle.

Patent Document 1 discloses an example of a fixed type constant velocity joint.
This fixed type constant velocity joint includes an outer ring, an inner ring, a plurality of balls, and a cage.

  The outer ring is a cylindrical body whose one end is open. One end of a first rotating shaft extending linearly is fixed to an end of the outer ring opposite to the opening. The inner peripheral surface of the outer ring is constituted by a first inner peripheral surface that is a part of the spherical surface. On the first inner peripheral surface, a plurality of first holding grooves are formed.

  The inner ring has a smaller diameter than the outer ring and is arranged in the inner peripheral space of the outer ring. One end of a second rotating shaft that extends linearly from the inner ring toward the side opposite to the first rotating shaft is fixed to the inner ring. The outer peripheral surface of the inner ring is constituted by a first outer peripheral surface that is a part of a spherical surface. On this first outer peripheral surface, the same number of second holding grooves as the first holding grooves are formed.

  Between the first inner peripheral surface of the outer ring and the first outer peripheral surface of the inner ring, the same number of balls as the first holding groove and the second holding groove are provided. Each ball is rotatably engaged with one first holding groove and one second holding groove.

A cage, which is a tubular member, is disposed between the first inner peripheral surface of the outer race and the first outer peripheral surface of the inner race.
The outer peripheral surface and the inner peripheral surface of the cage are both constituted by a second outer peripheral surface and a second inner peripheral surface which are part of a spherical surface. The outer race and the cage are rotatable relative to each other. Further, the inner ring and the cage can rotate relative to each other.
The same number of ball support holes as balls are formed in the cage as through holes. Each ball support hole rotatably supports each ball. Each ball supported by each ball support hole has a ball position plane that is a plane orthogonal to the bisector of the angle formed by the first rotation axis and the second rotation axis at any angle. Located on top.

This fixed type constant velocity joint operates as follows.
For example, when the first rotating shaft rotates around its own axis, each ball engaging with each first holding groove of the outer race revolves around the first rotating shaft while rotating. Then, the revolving force of each ball is transmitted to each second holding groove, so that the inner race and the second rotating shaft rotate around the second rotating shaft at the same speed as the outer race. That is, each ball transmits the rotational torque of the outer wheel to the inner wheel.

The outer ring and the inner ring are rotatable while changing the angle between the first rotation axis and the second rotation axis.
Each ball is always held on the ball position plane by the ball support hole of the cage. Therefore, regardless of the size of the angle between the first rotation shaft and the second rotation shaft, when the first rotation shaft rotates, the second rotation shaft rotates at the same speed as the first rotation shaft.

  When the second rotating shaft rotates around its own axis, the first rotating shaft is at the same speed as the second rotating shaft, regardless of the size of the angle between the first rotating shaft and the second rotating shaft. Rotate.

JP 2006-26659 A

  Since the ball is engaged with the inner surface of the first holding groove and the inner surface of the second holding groove, respectively, when the first rotating shaft and the second rotating shaft rotate, the ball is separated from the first holding groove and the second holding groove respectively. Receive strength. Then, each ball is pressed against a part of the inner surface of the corresponding ball support hole by the combined force of the forces received by the balls from the first holding groove and the second holding groove. Then, a reaction force due to the resultant force is exerted on the ball from the part of the inner surface of the ball support hole.

The radius of the first inner peripheral surface of the outer race is slightly larger than the radius of the second outer peripheral surface of the cage. Therefore, a small clearance exists between the first inner peripheral surface of the outer race and the second outer peripheral surface of the cage. Similarly, the radius of the first outer peripheral surface of the inner race is slightly smaller than the radius of the second inner peripheral surface of the cage. Therefore, a small clearance exists between the first outer peripheral surface of the inner race and the second inner peripheral surface of the cage.
Therefore, the contact position of each ball with the inner surfaces of the first holding groove and the second holding groove changes according to a change in the angle between the first rotation axis and the second rotation axis.

When the first rotation axis and the second rotation axis are coaxial, the positional relationship between the corresponding first holding groove and the corresponding second holding groove of all the ball support holes is the same.
At this time, the direction of the reaction force extending from the inner surface of the ball support hole to the ball is substantially parallel to the axis of the cage (that is, the axis of the first rotation axis and the second rotation axis).
As shown in FIG. 5, at this time, each ball comes into contact at one point with an intermediate portion between the bottom of the inner surface of the corresponding second holding groove and the end (edge) on the opening side. In other words, at this time, each ball is not largely moved from the bottom side of the corresponding second holding groove to the corresponding first holding groove side by the reaction force.

When the first rotation axis and the second rotation axis are not coaxial, the positional relationship between the corresponding first holding groove and the second holding groove of each ball support hole differs for each ball support hole. Therefore, the magnitude of the resultant force exerted on the ball supported by one ball support hole is the largest among all the balls. In other words, the above-mentioned reaction force generated by one ball supporting hole is the largest among all the ball supporting holes. Hereinafter, one ball support hole that generates the maximum reaction force is referred to as a “maximum reaction force ball support hole”. Further, the direction of the reaction force extending from the inner surface of each ball support hole to each ball differs for each ball support hole.
When the input to the first rotating shaft is constant, the magnitude of the reaction force generated by the inner surface of the reaction force maximum ball support hole when the first rotating shaft and the outer ring rotate is determined by the first rotating shaft and the third rotating shaft. It changes depending on the angle between the two rotation axes, and becomes maximum when the angle becomes the maximum angle. Similarly, when the input to the second rotating shaft is constant, the magnitude of the reaction force generated by the inner surface of the reaction force maximum ball support hole when the second rotating shaft and the inner ring rotate is equal to the first rotating shaft. It changes according to the angle formed by the second rotation axis, and becomes maximum when the angle becomes the maximum angle.

Therefore, for example, when the vehicle makes a U-turn, when the angle between the first rotation axis and the second rotation axis is the maximum angle and a large rotation torque is input to the first rotation axis or the second rotation axis, the ball The resultant force is received from the first holding groove and the second holding groove.
However, due to the clearance, the resultant force at this time is not orthogonal to the part of the inner surface of the reaction force maximum ball support hole. For this reason, the reaction force generated at this time causes the ball supported by the reaction force maximum ball support hole to largely move from the bottom side of the corresponding second holding groove to the corresponding first holding groove side. As a result, as shown in FIG. 6, the ball comes into contact at one point with the vicinity of the open end of the inner surface of the corresponding second holding groove. At this time, the ball comes into contact with the inner surface of the second holding groove with a strong force. Is highly likely to undergo plastic deformation.
If plastic deformation occurs at the edge of the second holding groove, the subsequent operation of the fixed type constant velocity joint may not be smooth.

  The present invention has been made to address the above-mentioned problems. That is, one of the objects of the present invention is that the first rotation shaft or the second rotation when the angle between the first rotation shaft integrated with the outer ring and the second rotation shaft integrated with the inner ring is the maximum angle. When the rotational torque is input to the shaft, the ball supported in the ball support hole exerts the maximum force on the corresponding ball in all the ball support holes near the edge of the inner surface of the second holding groove of the inner ring. An object of the present invention is to provide a fixed type constant velocity joint which is less likely to be pressed against excessive force.

The fixed type constant velocity joint of the present invention is:
An outer ring (20) integral with the first rotating shaft (40), the outer ring (20) being a part of a spherical surface and having a first inner peripheral surface (21) in which a plurality of first holding grooves (22) are formed;
A center of curvature that is rotatably disposed in the inner peripheral side space of the first inner peripheral surface and is integrated with the second rotation shaft (45) and has a smaller diameter than the first inner peripheral surface and different from the first inner peripheral surface. An inner ring (25) having a first outer peripheral surface (26) that is a part of a spherical surface having a plurality of second holding grooves (27),
A plurality of balls (35) rotatably engaged with one of the first holding grooves and one of the second holding grooves, respectively;
A second outer peripheral surface (31) rotatably contacting the first inner peripheral surface and a second inner peripheral surface (32) rotatably contacting the first outer peripheral surface, and are coaxial with each other. A cage (30) having a central axis (30X) coaxial with the first rotation axis and the second rotation axis;
With
Each of the balls is positioned so that the cage is always positioned on a ball position plane (PB) orthogonal to the bisector (Lθ) of the angle formed by the first rotation axis and the second rotation axis. A plurality of ball support holes (33) for supporting;
Each of the ball support holes is a plane formed at two locations on its inner surface, each of which is a plane facing each other in a direction parallel to the central axis while being parallel to each other, and one ball is located therebetween. A first contact portion (33a) and a second contact portion (33b);
When the angle between the first rotation axis and the second rotation axis becomes the maximum angle, one of the ball support holes is moved by the force received by the first contact portion of the ball from the corresponding ball. , A reaction force maximum ball support hole (33X) that exerts a larger reaction force than the other first contact portions,
The reaction force is the combined force of two forces exerted by the first holding groove and the second holding groove on the ball supported by the maximum ball support hole, and from the second contact portion side to the first contact portion side The shape of the first holding groove and the second holding groove and the ball support so that the pocket load (AF) toward the head and the plane formed by the first contact portion of the reaction force maximum ball support hole are orthogonal to each other. the shape of the hole, and the outer diameter of the ball is set, and the plane in which the first contact portion is configured, you are inclined with respect to a plane perpendicular to the central axis.

The “perpendicular” between the pocket load and the plane formed by the first contact portion includes not only perfect perpendicular but also substantially perpendicular. The plane orthogonal to the central axis substantially coincides with the ball position plane.

When the first rotation axis and the second rotation axis are not coaxial, the positional relationship between the corresponding first holding groove and the second holding groove of each ball support hole differs for each ball support hole. Therefore, the magnitude of the resultant force of the force exerted by the first holding groove and the second holding groove on the ball supported by the maximum reaction force ball support hole, which is one ball support hole, and the maximum reaction force ball support hole The magnitude of the reaction force exerted on the ball is the largest of all the balls. Further, the direction of the reaction force from the first contact portion of each ball support hole to each ball is different for each ball support hole.
When the input to the first rotating shaft is constant, the magnitude of the reaction force generated by the inner surface of the reaction force maximum ball support hole when the first rotating shaft and the outer ring rotate is determined by the first rotating shaft and the third rotating shaft. It changes depending on the angle between the two rotation axes, and becomes maximum when the angle becomes the maximum angle. Similarly, when the input to the second rotating shaft is constant, the magnitude of the reaction force generated by the inner surface of the reaction force maximum ball support hole when the second rotating shaft and the inner ring rotate is equal to the first rotating shaft. It changes according to the angle formed by the second rotation axis, and becomes maximum when the angle becomes the maximum angle.
Therefore, the magnitude of the force (reaction force) exerted on the ball from the first contact portion of the maximum reaction force ball support hole becomes maximum when the angle becomes the maximum angle.

However, in the present invention, when the angle between the first rotation axis and the second rotation axis becomes the maximum angle, the plane forming the first contact portion of the reaction force maximum ball support hole is the first holding groove and the second holding groove. It is the resultant of the two forces exerted on the ball from the two holding grooves, and is orthogonal to the pocket load from the second contact portion to the first contact portion. Therefore, when the angle formed between the first rotation axis and the second rotation axis reaches the maximum angle, the ball (reaction force) exerted on the ball by the first contact portion of the reaction force maximum ball support hole causes the ball to move toward the inner ring. The possibility of being largely moved from the bottom side of the second holding groove to the first holding groove side of the outer race is small.
Therefore, when the rotation torque is input to the first rotation shaft or the second rotation shaft when the angle formed between the first rotation shaft and the second rotation shaft is the maximum angle, the inner surface of the second holding groove of the inner race is formed. The possibility that the ball supported by the maximum reaction force ball support hole is pressed against the vicinity of the edge by an excessive force is small.

  In the above description, in order to facilitate understanding of the present invention, the names and / or symbols used in the embodiments are attached in parentheses to the configurations of the invention corresponding to the embodiments described later. However, each component of the present invention is not limited to the embodiment defined by the above reference numerals. Other objects, other features, and attendant advantages of the present invention will be easily understood from the description of the embodiments of the present invention described with reference to the following drawings.

It is sectional drawing when the 1st rotation axis and the 2nd rotation axis of the fixed type constant velocity joint which concern on embodiment of this invention are coaxial. It is an expanded sectional view of the principal part of FIG. FIG. 2 is a cross-sectional view similar to FIG. 1 when a relative position between a first rotation axis and a second rotation axis has reached a maximum angle position. FIG. 4 is an enlarged sectional view of a main part of FIG. 3. It is sectional drawing of the principal part of the outer ring and the inner ring cut | disconnected in the position which passes through the 1st holding groove and the 2nd holding groove when the 1st rotation shaft of the outer ring of a conventional example and the 2nd rotation shaft of an inner ring are coaxial. FIG. 6 is a cross-sectional view similar to FIG. 5 when an angle formed between a first rotation axis and a second rotation axis is a maximum angle.

Hereinafter, a fixed type constant velocity joint 10 according to an embodiment of the present invention will be described with reference to the accompanying drawings.
The fixed type constant velocity joint 10 of the present embodiment is provided at a front portion of a vehicle and connected to left and right front wheels (not shown). That is, a pair of left and right fixed type constant velocity joints 10 are provided at the front of the vehicle.
The fixed type constant velocity joint 10 has an outer ring 20, an inner ring 25, a cage 30, and a ball 35 as main components.

  The metal outer race 20 is integrally provided with a driven shaft 40 extending linearly. The driven shaft 40 is coaxially connected to a rotation shaft of a front wheel (not shown) of the vehicle. The outer race 20 is a rotationally symmetric body centered on an extension 40X of the axis of the driven shaft 40.

  An opening 20 a is formed at the end of the outer ring 20 opposite to the driven shaft 40. The inner peripheral surface of the outer ring 20 is constituted by a first inner peripheral surface 21 which is a part of a spherical surface.

  A plurality of first holding grooves 22 are formed on the first inner peripheral surface 21. The cross-sectional shape of each first holding groove 22 is the same as that shown in FIGS. The first holding grooves 22 are arranged at equal angular intervals in a circumferential direction about an extension 40X of the driven shaft 40. Furthermore, each first holding groove 22 extends along the first inner peripheral surface 21 from the driven shaft 40 side toward the opening 20a side. The radial distance of each first holding groove 22 from the extension line 40X gradually increases from the driven shaft 40 side toward the opening 20a side. Further, the depth of each first holding groove 22 gradually increases from the driven shaft 40 side toward the opening 20a side.

  One end of a linearly extending drive shaft 45 is fixed to one end of the metal inner race 25 (see phantom lines in FIGS. 1 and 3). The drive shaft 45 is a drive shaft connected to a propeller shaft via a differential gear. The inner race 25 is a rotationally symmetric body about an extension 45X of the axis of the drive shaft 45. The outer diameter of the inner ring 25 is smaller than the inner diameter of the outer ring 20. An end face of the inner race 25 on the side opposite to the drive shaft 45 is constituted by a tip end face 25a.

  The outer peripheral surface of the inner ring 25 is constituted by a first outer peripheral surface 26 which is a part of a spherical surface. The radius of the first outer peripheral surface 26 is smaller than the radius of the first inner peripheral surface 21.

  On the first outer peripheral surface 26, the same number of second holding grooves 27 as the first holding grooves 22 are formed. The cross-sectional shape of each second holding groove 27 is the same as that shown in FIGS. The second holding grooves 27 are arranged at equal angular intervals in the circumferential direction around the extension line 45X of the drive shaft 45 (that is, the same intervals as the intervals between the first holding grooves 22). Further, each second holding groove 27 extends along the first outer peripheral surface 26 from the drive shaft 45 side toward the distal end surface 25a side. The radial distance of each second holding groove 27 from the extension line 45X gradually increases from the drive shaft 45 side toward the distal end surface 25a. Further, the depth of each second holding groove 27 gradually increases from the drive shaft 45 side toward the distal end surface 25a.

The metal cage 30 is a rotationally symmetric body about the central axis 30X.
The outer peripheral surface of the cage 30 is constituted by a second outer peripheral surface 31 which is a part of the spherical surface.
The cage 30 is disposed in the internal space of the outer race 20 such that the second outer peripheral surface 31 faces the first inner peripheral surface 21. However, the radius of the second outer peripheral surface 31 is slightly smaller than the radius of the first inner peripheral surface 21. Therefore, the center of curvature of the second outer peripheral surface 31 is not completely the same as the center of curvature of the first inner peripheral surface 21, and is slightly shifted from each other. That is, there is a minute clearance between the first inner peripheral surface 21 of the outer race 20 and the second outer peripheral surface 32 of the cage 30. However, a part of the first inner peripheral surface 21 and a part of the second outer peripheral surface 32 can be in contact with each other.
A portion of the inner peripheral surface of the cage 30 except for both ends in the central axis 30X direction is constituted by a second inner peripheral surface 32 which is a part of a spherical surface.
The inner ring 25 is disposed in the internal space of the cage 30 so that the first outer peripheral surface 26 faces the second inner peripheral surface 32.
The radius of the second inner peripheral surface 32 is slightly larger than the radius of the first outer peripheral surface 26. Therefore, the center of curvature of the second inner peripheral surface 32 is not completely the same as the center of curvature of the first outer peripheral surface 26, and is slightly shifted from each other. That is, a small clearance exists between the first outer peripheral surface 26 of the inner race 25 and the second inner peripheral surface 32 of the cage 30. However, the first outer peripheral surface 26 and a part of the second inner peripheral surface 32 can be in contact with each other.

The outer race 20 and the cage 30 are relatively rotatable in a state where the second outer peripheral surface 31 and a part of the first inner peripheral surface 21 are in contact with each other.
Further, the cage 30 and the inner race 25 are relatively rotatable in a state where a part of the first outer peripheral surface 26 and a part of the second inner peripheral surface 32 are in contact with each other.
Therefore, the outer race 20 can rotate relative to the inner race 25, and the inner race 25 can rotate relative to the outer race 20.

  When the outer race 20 and the inner race 25 rotate relative to each other, the angle between the extension 40X of the driven shaft 40 and the extension 45X of the drive shaft 45 changes. That is, the outer race 20 and the inner race 25 have the coaxial position shown in FIGS. 1 and 2 in which the angle between the extension line 40X and the extension line 45X is 0 °, and the angle between the extension line 40X and the extension line 45X is the maximum angle. 3 and 4 can be rotated relative to each other. As shown in FIG. 1, when the outer ring 20 and the inner ring 25 are located at the same coaxial position, the center axis 30X of the cage 30 coincides with the extension lines 40X and 45X.

Further, the cage 30 has the same number of ball support holes 33 as the first holding grooves 22 and the second holding grooves 27 as through holes. The ball support holes 33 are arranged at equal angular intervals in the circumferential direction around the central axis 30 </ b> X of the cage 30 (ie, at the same interval as the interval between the first holding grooves 22).
As shown in FIGS. 2 and 4, each ball support hole 33 is substantially square. That is, the inner peripheral surface of each ball support hole 33 is constituted by four surfaces. Two of these four surfaces are constituted by a first contact portion 33a and a second contact portion 33b facing each other in a direction parallel to the direction of the central axis 30X. The first contact portion 33a and the second contact portion 33b are configured by planes parallel to each other. However, the first contact portion 33a and the second contact portion 33b are not orthogonal to the direction of the central axis 30X. In other words, the straight line L perpendicular to the extension line 40X shown in FIG. 2 and extending in the direction passing through the ball support hole 33 is not completely parallel to the first contact portion 33a and the second contact portion 33b, and is not parallel to each other. It is slightly inclined. When the outer race 20 and the inner race 25 are located at the same coaxial position, the first contact portion 33a of each ball support hole 33 is located on the drive shaft 45 side, and the second contact portion 33b of each ball support hole 33 is located on the driven shaft 40 side. Located in.

The ball 35, which is a metal sphere, has a slightly smaller diameter than the inner diameter of the ball support hole 33.
The number of the balls 35 is equal to the number of the first holding grooves 22, the second holding grooves 27, and the ball support holes 33. Each ball 35 is rotatably inserted into the ball support hole 33 of the cage 30 and is rotatably engaged with the corresponding first holding groove 22 and corresponding second holding groove 27. More specifically, each ball 35 comes into contact with the inner surface of the corresponding first holding groove 22 and second holding groove 27 at a single point (as in the case shown in FIGS. 5 and 6). However, the contact position of each ball 35 with the inner surfaces of the first holding groove 22 and the second holding groove 27 changes according to the change in the angle between the driven shaft 40 and the drive shaft 45.

As is well known, the positions of the respective centers of curvature of the first inner peripheral surface 21, the bottom 22a of each first holding groove 22, the first outer peripheral surface 26, and the bottom 27a of each second holding groove 27 are shifted from each other, In addition, they have a predetermined positional relationship with each other.
Therefore, each ball 35 rotatably supported by each ball support hole 33 of the cage 30 is located at a ball position orthogonal to the bisector Lθ of the angle θ formed by the extension line 40X and the extension line 45X (coincident with 30X). It is always located on the plane PB (see FIG. 3). In other words, when the relative position between the outer race 20 and the inner race 25 is any position between the coaxial position and the maximum angle position, each ball 35 is located on the ball position plane PB.

Next, the operation of the fixed type constant velocity joint 10 will be described.
When the rotational force of the vehicle engine is transmitted to the drive shaft 45, which is the drive shaft, via the propeller shaft and the differential gear, the drive shaft 45 rotates around the extension 45X. Then, each ball 35 engaging with each second holding groove 27 of the inner ring 25 revolves around the extension line 45X together with the inner ring 25 while rotating. Then, the revolving force of each ball 35 is transmitted to each first holding groove 22 of the outer ring 20, so that the outer ring 20 and the driven shaft 40 rotate around the extension line 40X at the same speed as the drive shaft 45 and the inner ring 25. That is, each ball 35 transmits the rotational torque of the inner race 25 to the outer race 20. Therefore, the left and right front wheels rotate around the driven shaft 40.

When the front wheel moves up and down with respect to the vehicle body, the angle between the extension 40X of the driven shaft 40 and the extension 45X of the drive shaft 45 changes.
However, regardless of the relative position of the outer ring 20 and the inner ring 25 between the coaxial position and the maximum angular position, each ball 35 is located on the ball position plane PB.
Therefore, the front wheel and the driven shaft 40 rotate at the same speed as the drive shaft 45 irrespective of the size of the angle between the extension line 40X and the extension line 45X.

  The detailed movement of each ball 35 when the drive shaft 45 and the driven shaft 40 rotate are as follows.

  Regardless of the angle between the extension line 40X and the extension line 45X, when the drive shaft 45 and the inner race 25 rotate, each ball 35 is moved from one point on the inner surface of the corresponding second holding groove 27 to the inside of the ball 35 It receives a force F1 directed to the side (see FIGS. 2 and 4). The force F1 is a force in a direction toward the center of the ball 35. Further, since each ball 35 pushes a point on the inner surface of the corresponding first holding groove 22, a force (reaction force) F2 is received from the corresponding point on the inner surface of the corresponding first holding groove 22 toward the center of the ball 35. (See FIGS. 2 and 4).

Regardless of the angle between the extension line 40X and the extension line 45X, the pocket load AF (see FIG. 2 and FIG. 4) which is the sum of the forces F1 and F2 and reaches each ball 35 is approximately equal to the tip. The force is directed from the surface 25a and the driven shaft 40 toward the drive shaft 45 and the opening 20a. In other words, the pocket load AF is a force having a small angle formed by a straight line connecting the first contact portion 33a and the second contact portion 33b of each ball support hole 33.
Therefore, when the drive shaft 45 and the inner race 25 rotate, each ball 35 is pressed against the corresponding first contact portion 33 a of the ball support hole 33 by the pocket load AF. As a result, each ball 35 receives a reaction force RF from the corresponding first contact portion 33a (see FIGS. 2 and 4).

  When the relative position between the driven shaft 40 and the drive shaft 45 is coaxial, the positional relationship between the corresponding first holding groove 22 and the second holding groove 27 of each ball support hole 33 becomes the same. Therefore, the magnitude and direction of the pocket load AF applied to the ball 35 supported by each ball support hole 33 and the reaction force RF applied to each ball 35 from the first contact portion 33a are the same between the balls 35. Become.

On the other hand, when the relative position between the driven shaft 40 and the drive shaft 45 is not coaxial, the positional relationship between the corresponding first holding groove 22 and the second holding groove 27 of each ball support hole 33 is determined by each ball support hole 33. Different for each hole 33. Therefore, the pocket load AF applied to the ball 35 supported by the maximum reaction force ball support hole 33X (see FIGS. 2 and 4), which is one ball support hole 33, and the ball 35 extends from the first contact portion 33a to each ball 35. The magnitude of the reaction force RF is maximum among all the ball support holes 33 and the balls 35.
Further, when the relative position between the driven shaft 40 and the drive shaft 45 is not coaxial, the directions of the pocket load AF and the reaction force RF are different for each ball support hole 33.

  When the input to the drive shaft 45 is constant, the magnitude of the reaction force RF generated by the first contact portion 33a of the reaction force maximum ball support hole 33X when the drive shaft 45 and the inner race 25 rotate is determined by the driven shaft It changes depending on the angle between the drive shaft 40 and the drive shaft 45, and becomes maximum when the angle becomes the maximum angle.

  Therefore, for example, when the vehicle makes a U-turn, the angle formed between the driven shaft 40 and the drive shaft 45 becomes the maximum angle, and when a large rotational torque is input to the drive shaft 45, the first reaction force ball support hole 33X has the first angle. The contact portion 33a generates a large reaction force RF.

  However, as shown in FIG. 4, the direction of the pocket load AF applied to the ball 35 supported by the maximum reaction force ball support hole 33X at this time is a direction completely orthogonal to the first contact portion 33a. Therefore, the direction of the reaction force RF generated by the first contact portion 33a of the maximum reaction force ball support hole 33X is a direction completely orthogonal to the first contact portion 33a.

Therefore, the ball 35 supported by the maximum reaction force ball support hole 33X is pushed toward the second contact portion 33b of the maximum reaction force ball support hole 33X by the reaction force RF received from the corresponding first contact portion 33a. Accordingly, at this time, the ball 35 supported by the maximum reaction force ball support hole 33X is moved by the reaction force RF from the bottom 27a side of the second holding groove 27 to the first holding groove 22 side of the outer race 20 (the opening of the second holding groove 27). There is little possibility of being largely moved to the end side).
Therefore, when the relative position between the outer race 20 and the inner race 25 reaches the maximum angular position, the ball 35 supported by the maximum reaction force ball support hole 33X is positioned near the edge of the inner surface of the second holding groove 27 of the inner race 25. Is pressed with an excessive force, and as a result, the edge of the second holding groove 27 is less likely to be plastically deformed.

  When the driven shaft 40 and the drive shaft 45 become non-coaxial in a mode different from that shown in FIGS. 3 and 4, another ball support hole 33 different from the illustrated maximum reaction force ball support hole 33X is formed. The maximum reaction force ball support hole 33X is obtained.

  As described above, the present invention has been described based on the above embodiments. However, the present invention is not limited to the above embodiments, and various modifications can be made without departing from the object of the present invention.

  For example, the driven shaft 40 may be fixed to the inner race 25 and the drive shaft 45 may be fixed to the outer race 20.

  When the relative position between the outer ring 20 and the inner ring 25 reaches the maximum angle position, the directions of the pocket load AF and the reaction force RF are not completely orthogonal to the first contact portion 33a, but are completely orthogonal. The shape of the first holding groove 22 and the second holding groove 27, the shape of the ball support hole 33, and the outer diameter (radius of the outer surface) of the ball 35 may be set so as to be slightly inclined. However, in this case, it is preferable that the reaction force RF be inclined toward the center axis 30X of the cage 30 with respect to the direction orthogonal to the first contact portion 33a. With this configuration, when the relative position between the outer race 20 and the inner race 25 reaches the maximum angular position, each ball 35 is pressed by a reaction force RF against the vicinity of the edge of the inner surface of the second holding groove 27 with a strong force. Is prevented.

  The fixed type constant velocity joint 10 may be used as a rotational force transmitting means in various industrial machines.

Reference Signs List 20 outer ring, 21 first inner peripheral surface, 22 first retaining groove, 25 inner ring, 26 first outer peripheral surface, 27 second retaining groove, 30 ... Cage, 31 ... Second outer peripheral surface, 32 ... Second inner peripheral surface, 33 ... Ball support hole, 33a ... First contact part,
33b: second contact portion, 35: ball, 40: driven shaft (first rotation shaft, second rotation shaft), 45: drive shaft (second rotation shaft, first rotation shaft) .

Claims (1)

An outer ring that is part of a spherical surface and has a first inner peripheral surface on which a plurality of first holding grooves are formed,
A spherical surface that is rotatably disposed in the inner peripheral side space of the first inner peripheral surface and is integrated with the second rotating shaft, and has a smaller diameter than the first inner peripheral surface and a center of curvature different from the first inner peripheral surface. And an inner ring having a first outer peripheral surface on which a plurality of second holding grooves are formed,
A plurality of balls each rotatably engaged with one of the first holding grooves and one of the second holding grooves,
The first outer peripheral surface rotatably contacting the first inner peripheral surface, and the second inner peripheral surface rotatably contacting the first outer peripheral surface, and the first coaxial with each other A cage having a central axis coaxial with a rotation axis and the second rotation axis;
With
A plurality of ball supports respectively supporting the balls so that the cage is always positioned on a ball position plane orthogonal to a bisector of an angle formed by the first rotation axis and the second rotation axis. With holes,
Each of the ball support holes is a plane formed at two locations on its inner surface, each of which is a plane facing each other in a direction parallel to the central axis while being parallel to each other, and one ball is located therebetween. Comprising one contact portion and a second contact portion,
When the angle between the first rotation axis and the second rotation axis becomes the maximum angle, one of the ball support holes is moved by the force received by the first contact portion of the ball from the corresponding ball. In contrast, a reaction force maximum ball support hole that exerts a larger reaction force than the other first contact portions,
The reaction force is the combined force of two forces exerted by the first holding groove and the second holding groove on the ball supported by the maximum ball support hole, and from the second contact portion side to the first contact portion side The shape of the first holding groove and the second holding groove, the shape of the ball supporting hole so that the pocket load toward the head and the plane formed by the first contact portion of the reaction force maximum ball supporting hole are orthogonal to each other. , And the outer diameter of the ball is set , and the plane formed by the first contact portion is inclined with respect to a plane orthogonal to the central axis ,
Fixed constant velocity joint.

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