JP4624892B2 - Constant velocity universal joint - Google Patents

Description

  The constant velocity universal joint of the present invention connects the drive side rotary shaft and the driven side rotary shaft so that torque can be transmitted at a constant angular speed even when both shafts are angled. It is used as a constant velocity universal joint for machine power transmission.

A constant velocity universal joint is generally used for an axle connecting portion of an automobile drive shaft and a shaft bending connecting portion of a steering shaft. As this constant velocity universal joint, as a fixed type that allows only angular displacement, a Zepper type constant velocity universal joint (see Patent Document 1) and an undercut-free type (hereinafter referred to as UJ type) constant velocity universal joint (see Patent Document 2). )It has been known. As one of sliding types that allow axial displacement in addition to angular displacement, a so-called double offset type (hereinafter referred to as DOJ type) constant velocity universal joint (see Patent Document 3) is known. This DOJ type constant velocity universal joint is obtained by offsetting the center positions of the outer spherical surface and inner spherical surface of the cage holding the ball by equal distances in the opposite direction from the joint center. The surface is a cylindrical surface, but the inner peripheral surface is a spherical surface and is used as a fixed type.
US Patent No. 2046584 JP-A-53-65547 JP-A-57-76323

    In DOJ type constant velocity universal joints, when the joint is rotated at a high operating angle, if the ball protrudes outward from the guide groove of the outer joint member, the ball is prevented from jumping radially outward from the cage window. Can not do it. For this reason, in the conventional DOJ type constant velocity universal joint, it is necessary to always store the ball in the guide groove of the outer joint member, so that the maximum operating angle of the joint is generally suppressed to 25 °, The limit was 31 °.

    In order to further increase the operating angle of the joint, for example, about 60 °, the ball must be taken out from the guide groove of the outer joint member. At this time, if the ball guide surface of the cage is a flat surface, the ball falls out from the window of the cage, and the constant velocity universal joint loses its function.

  An object of the present invention is to provide a constant velocity universal joint capable of realizing a maximum operating angle of 60 ° by taking it out of an outer joint member without dropping the ball.

  In order to solve the above problem, the invention of claim 1 is directed to an outer joint member in which a plurality of guide grooves extending in the axial direction are formed on the inner peripheral surface, and an inner side in which a plurality of guide grooves extending in the axial direction are formed on the outer diameter spherical surface. A joint member, a torque transmission ball disposed on each of a plurality of ball tracks formed in cooperation with a guide groove of the outer joint member and a guide groove of the inner joint member; and an inner peripheral surface of the outer joint member A cage having an outer diameter spherical surface that is in sliding contact and an inner diameter spherical surface that is in sliding contact with the outer diameter spherical surface of the inner joint member and holding a torque transmission ball, and the ball center of the guide groove of the outer joint member at a joint operating angle of 0 ° The trajectory is a first straight portion parallel to the joint central axis, and the ball center trajectory of the guide groove of the inner joint member is parallel to the first straight portion within a predetermined range passing through the joint center and perpendicular to the joint central axis. The second straight line and the second straight line In a predetermined range from both ends of the inner joint member, the inner joint member has an arc portion centered on the center of the outer diameter spherical surface, and the center positions of the inner diameter spherical surface and the outer diameter spherical surface of the cage are from the joint center along the joint central axis. It is characterized in that it is offset by an equal distance in the opposite direction, and the outside diameter side window opening size of the window of the cage holding the ball is made smaller than the ball diameter.

    In the constant velocity universal joint of the present invention, when the operating angle is 0 °, the ball is held in the guide grooves respectively corresponding to the first straight portion of the outer joint member and the second straight portion of the inner joint member, and transmits torque. . The first linear portion and the second linear portion are parallel to each other, but the center positions of the inner spherical surface and the outer spherical surface of the cage are offset by an equal distance in the opposite direction from the joint center, and the joint operating angle direction of the cage is As a result of the rotation being constrained, the center of each ball is held in a plane that includes the joint center and is perpendicular to the joint center axis. When the operating angle θ is generated, the ball is chased at the intersection of the first linear portion and the second linear portion, and is oriented in a plane that bisects the operating angle θ by the cage, whereby the constant velocity of the joint is obtained. Is secured. When the operating angle θ further increases and the center of the ball deviates from the second linear portion and reaches the arc portion, the ball deviates from the guide groove of the outer joint member. In this state, the ball is held in the guide groove corresponding to the arc portion of the inner joint member by the cage having an outer diameter side window opening dimension smaller than the ball diameter, and the ball is prevented from falling off. Therefore, the constant velocity universal joint according to the present invention makes it possible to realize an operating angle exceeding 30 ° and reaching 60 °.

The invention of claim 2 is the invention of claim 1, wherein the outer diameter side portion of the cage window smaller than the ball diameter is a separate member that can be retrofitted after the ball is inserted into the window from the outer diameter side. It is characterized by comprising.
By comprising in this way, a ball | bowl can be inserted from the cage outer diameter side in the assembly process of the joint, and the assembly of the joint is facilitated.

    According to a third aspect of the present invention, in the first aspect of the invention, the guide ring for slidingly guiding the outer diameter spherical surface of the inner joint member to the cylindrical surface while the inner diameter surface of the cage on the joint opening side is a cylindrical surface. And a retaining ring for retaining the guide ring.

  When the ball guide surface of the cage is narrowed inward on the outer diameter side, the ball cannot be inserted into the window from the outer diameter side of the cage during assembly of the joint. The ball is inserted into the window from the inner diameter side of the cage. Then, the inner joint member must be inserted into the cage from the joint opening side, so the inner diameter surface of the cage on the joint opening side is a cylindrical surface. It is necessary to keep. If this cylindrical surface is left as it is, it will not prevent the inner joint member from being pulled out. Therefore, the inner joint member is prevented from being pulled out by the guide ring and the retaining ring.

According to a fourth aspect of the present invention, in the first aspect of the present invention, the arc portion of the ball center locus of the guide groove of the inner joint member is the ball center locus of the guide groove of another member fitted to the outer periphery of the main body of the inner joint member. It is characterized by comprising.
As described above, torque transmission is performed by the ball in a state where the center of the ball is in the straight portion (first straight portion and second straight portion) of the outer joint member and the inner joint member. Therefore, the guide groove corresponding to the straight portion is required to have a predetermined strength and dimensional accuracy, and the processing cost increases according to the required level. On the other hand, in a state where the center of the ball is in the arc portion of the inner joint member, the ball is out of the guide groove of the outer joint member. For this reason, the torque transmission function of the ball has already been lost, and no load is applied to the guide groove of the inner joint member corresponding to the arc portion. Therefore, by configuring the inner joint member corresponding to the arc portion as a separate member, the material and processing method of the separate member can be selected at a lower cost than the inner joint member main body.

According to a fifth aspect of the present invention, in the first aspect of the invention, only the ball center locus of a part of the guide grooves among the plurality of guide grooves of the outer joint member and the inner joint member is the first straight portion of the first aspect, The ball center trajectory of the remaining guide groove is a single circular arc centering on the joint center.
That is, the number of ball tracks is usually 6 or 8 or more, but for example only 3 or 4 ball tracks (ie every other ball track), the ball center trajectory is as in claim 1 and the rest In this ball track, the ball center trajectories of the inner and outer guide grooves are formed as a single circular arc that overlaps the whole. Thereby, the torque which can be transmitted can be enlarged more.

    The invention of claim 6 is characterized in that, in the invention of claim 1, the inner peripheral surface of the outer joint member is an inner spherical surface which is in sliding contact with the outer spherical surface of the cage. In this case, the joint is a fixed type that allows only angular displacement.

    A seventh aspect of the invention is characterized in that, in the first aspect of the invention, the inner peripheral surface of the outer joint member is an inner cylindrical surface that is in linear contact with the outer spherical surface of the cage. In this case, the joint is a sliding type that allows both angular displacement and axial displacement.

In the constant velocity universal joint of the present invention, the arc parts on both sides of the ball center locus of the inner joint member are arc parts centered on the joint center, and the window opening dimension on the outer diameter side of the cage is made smaller than the ball diameter. Therefore, even when a high operating angle of 60 ° is taken, the center position of the ball does not move away from the center of the joint, and the ball can be held by the cage on the guide groove side of the inner joint member. Further, it is possible to achieve a high operating angle up to 60 ° while preventing the balls from falling off.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS. 1 to 4 are embodiments of a fixed type constant velocity universal joint, and FIGS. 5A and 5B are embodiments of a sliding type constant velocity universal joint. As shown in FIGS. 1A and 1B, the constant velocity universal joint includes an outer joint member 1 having a substantially straight cylindrical shape and an inner joint member 2 having an outer diameter spherical surface. The shaft is connected to the central hole of the inner joint member by spline or serration. The operating angle formed by the two joint members is 0 ° in FIG. 1A and about 55 ° (maximum operating angle θmax) in FIG.

    The inner peripheral surface of the outer joint member 1 forms an inner spherical surface 1a. The center A of the inner spherical surface 1a is offset from the joint center O by a predetermined distance f in one direction (leftward in FIG. 1A) along the joint center axis direction. A guide groove 1b extending in the joint central axis direction is formed in the inner spherical surface 1a. For example, six or eight guide grooves 1b are formed at equal intervals in the circumferential direction of the outer joint member 1 or a plurality of guide grooves 1b. The groove bottom shape of the guide groove 1b, that is, the ball center locus C1 of the guide groove 1b is configured by a first straight part ab parallel to the joint central axis as shown in FIG.

  The outer peripheral surface of the inner joint member 2 forms an outer diameter spherical surface 2a. The center B of the outer diameter spherical surface 2a is offset from the joint center O by a predetermined distance f in one direction (rightward in FIG. 1A) along the joint center axis direction. A guide groove 2b extending in the joint central axis direction is formed in the outer diameter spherical surface 2a. The number of guide grooves 2b is the same as the number of guide grooves 1b of the outer joint member 1, and is formed, for example, six or eight, or even more, at equal intervals in the circumferential direction of the inner joint member 2. The groove bottom shape of the guide groove 2b, that is, the ball center locus C2 of the guide groove 2b is composed of three tracks C2-1, C2-2 and C2-3. The first locus C2-1 is a second straight line portion de that is parallel to or overlaps with the first straight line portion ab within a predetermined range that passes through the joint center O and crosses the perpendicular V perpendicular to the joint center axis. Here, “parallel” refers to a case where a slight space is formed as play between the first straight line part ab and the second straight line part de. As shown in FIG. 4, when the first straight line portion ab and the second straight line portion de overlap at all, that is, when there is no gap between the first straight line portion ab and the second straight line portion de, the operating angle is 0. There is a risk that an abnormal surface pressure may be generated between the ball 3 and the guide grooves 1b and 2b at an angle. Therefore, it is desirable to form a slight space as play between the first straight line part ab and the second straight line part de. The second and third trajectories C2-2 and C2-3 have a radius R1 centering on the center B of the outer diameter spherical surface 2a of the inner joint member 2 extending from the both ends of the second linear portion de to the predetermined range. A pair of left and right arc portions cd, ef. The lengths of the arc portions cd and ef are basically equal, but may be different lengths.

  The portion of the guide groove corresponding to the arc portions cd and ef can be formed by processing the outer diameter spherical surface 2a of the inner joint member 2 as an integral body including the guide groove corresponding to the second linear portion de. it can. However, as shown in FIGS. 1 and 2, right-angle step portions 8a and 8b are formed on the outer diameter spherical surface of the inner joint member 2, and the annular separate members 9a and 9b fitted to the right-angle step portions 8a and 8b are formed. The arc portions cd and ef may be formed by the guide groove. When the ball 3 is in the arc portions cd and ef, the ball 3 is disengaged from the guide groove 1b of the outer joint member 1 and torque transmission is not performed. However, it can be made of, for example, a resin material that is inexpensive, lightweight, and easy to process.

    The retainer 4 is cylindrical as shown in FIGS. 1 and 3, and has an inner spherical surface 4c on the inner side and an outer spherical surface 4d on the outer side. The inner spherical surface 4c and the outer spherical surface 4d are in sliding contact with each other between the outer spherical surface 2a of the inner joint member 2 and the inner spherical surface 1a of the outer joint member 1 (surface sliding contact). Therefore, as shown in FIG. 1, the outer diameter spherical surface 4d is a spherical surface having a radius R2 centered on the center A, and the inner diameter spherical surface 4c is a spherical surface having a radius R3 centered on the center B.

  The cage 4 has the same number of windows 4b as the balls 3 in the circumferential direction. The ball 3 is accommodated in the window 4b. As shown in FIG. 3, the guide surfaces 4b1 and 4b2 are the inner peripheral surfaces of the window 4b and facing the joint axis direction. The ball guide surfaces 4b1 and 4b2 are narrow on the outer diameter side. In other words, the inner diameter side of the ball guide surface is a parallel straight line 4b1 with an interval equal to the ball diameter, but the outer diameter side of the ball guide surface is tapered so as to be slightly narrower than the ball diameter. It has become. The tapered portion may be formed by an inclined straight line, but in order to reduce the contact pressure with the ball 3, it is preferable to form a concave arc 4b2 that matches the outer peripheral curvature of the ball 3. In addition, you may comprise the part shown with the broken line in FIG. 3, ie, the outer diameter side part of the window 4b of the holder | retainer 4 smaller than a ball diameter by another member. After the ball 3 is inserted into the window 4b, this separate member is attached to the main body of the retainer 4 by welding, adhesion or shrink fitting, thereby facilitating the operation of inserting the ball 3.

  As shown in FIG. 2 (B), the inner diameter surface on the joint opening side of the cage 4 is a cylindrical surface having a constant inner diameter over a predetermined width, and a retaining ring 5 (circlip) is fitted into a groove 4a formed on the cylindrical surface. Combined. The guide ring 6 is fitted into a narrow annular wedge space formed inside the retaining ring 5 and between the retainer 4 and the window 4b. The guide ring 6 has an inner peripheral surface slidably fitted to the outer diameter spherical surface 2 a of the inner joint member 2, and an outer peripheral surface fixedly fitted to the inner diameter cylindrical surface of the cage 4. Further, the outer end of the guide ring 6 comes into contact with the inner surface of the retaining ring 5. A certain gap is secured between the inner end of the guide ring 6 and the ball 3.

  When the ball guide surface of the window 4b of the cage 4 is narrowed inward on the outer diameter side as shown in FIG. 3, the ball 3 cannot be inserted into the window 4b from the outer diameter side of the cage 4 when the joint is assembled. . The ball 3 is inserted into the window 4b from the inner diameter side of the cage 4. In this case, the inner joint member 2 must be inserted into the cage 4 from the joint opening side. Accordingly, the inner diameter surface of the cage 4 on the joint opening side needs to be a cylindrical surface. If this cylindrical surface is left as it is, it will not prevent the inner joint member 2 from being removed, so that the inner joint member 2 is secured by the guide ring 6 and the retaining ring 5.

  In the constant velocity universal joint of the present invention, the center A of the outer spherical surface 4d and the center B of the inner spherical surface 4c of the cage 4 are offset in the opposite direction from the joint center O in the state where the operating angle is 0 ° in FIG. Therefore, the cage 4 alone cannot rotate in either the clockwise direction or the counterclockwise direction. For this reason, the center of each ball 3 is held in a plane V including the joint center O and perpendicular to the joint center axis.

    When the inner joint member 2 is displaced by the operating angle θ with respect to the outer joint member 1 from the state where the operating angle is 0 °, the center of the ball 3 is at the intersection of the first straight portion ab and the second straight portion de. At the same time, the cage 4 orients the angle θ in a plane that bisects the angle θ, thereby ensuring constant velocity of the joint.

    Next, when the center of the ball 3 deviates from the second linear portion de and reaches the arc portion cd or ef, the ball 3 deviates from the guide groove 1 b of the outer joint member 1. In this state, the ball 3 is held in the guide groove 2b corresponding to the arc portions cd and ef of the inner joint member 2 by the cage 4 having an outer diameter side window opening dimension smaller than the ball diameter, and the ball 3 is prevented from falling off. Is done. Since the center of the arc portions cd and ef is the center B of the outer diameter spherical surface 2a of the inner joint member 2, that is, the center B of the inner diameter spherical surface 4c of the cage 4, the center of the ball 3 is in the arc portions cd and ef. The ball 3 is held in the window 4b of the cage 4 without being displaced radially from the center B. Thus, the constant velocity universal joint according to the present invention makes it possible to realize an operating angle that exceeds 30 ° and reaches 60 °. When the operating angle becomes θmax as shown in FIG. 1B, the shaft 7 cannot interfere with the outer joint member 1 and cannot be inclined further.

  Next, another embodiment of the constant velocity universal joint of the present invention will be described with reference to FIGS. 1A and 1B relate to an embodiment of a fixed type constant velocity universal joint, while FIGS. 5A and 5B relate to an embodiment of a sliding type constant velocity universal joint. 5A and 5B, the shape of the outer joint member 11 is different from that of FIGS. As shown in FIGS. 5A and 5B, the outer joint member 11 has a cylindrical cup shape with one end closed by an end wall 11c. An inner peripheral surface of the outer joint member 11 is an inner cylindrical surface 11a. A guide groove 11b extending linearly in the joint central axis direction is formed on the cylindrical surface 11a. The number of guide grooves 11 b is the same as the number of guide grooves 2 b of the inner joint member 2. The outer diameter spherical surface 4d of the cage 4 is in sliding contact with the cylindrical surface 11a of the outer joint member 11 by a plurality of lines (wire sliding contact).

  In this sliding type constant velocity universal joint, the inner joint member 2 is slidable in the direction of the arrow in FIG. FIG. 5B shows a state in which the inner joint member 2 is closest to the opening side of the outer joint member 11 and has a maximum operating angle θmax of about 55 °. In this state, the ball 3 is disengaged from the guide groove 11b of the outer joint member 11. However, the ball 3 is held in the guide groove 2b of the inner joint member 2 by the cage 4 having an outer diameter side window opening dimension smaller than the ball diameter. , Its dropout is prevented.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made based on the technical idea included in the claims.

(A) (B) is sectional drawing of the constant velocity universal joint which concerns on this invention. (A) is an expanded sectional view around the ball, (B) is a similar sectional view according to a modification. The expanded sectional view which exaggerates and shows the ball guide surface shape of the window of a holder | retainer. The figure which shows the ball | bowl center locus | trajectory of both guide grooves of an outer joint member and an inner joint member in piles. (A) (B) is sectional drawing of another constant velocity universal joint which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Outer joint member 1a Inner diameter spherical surface 1b, 2b Guide groove 2 Inner joint member 2a Outer diameter spherical surface 3 Torque transmission ball 4 Cage 4a Groove 4b Window 4c Inner diameter spherical surface 4d Outer diameter spherical surface 5 Retaining ring 6 Guide ring 7 Shaft 8a, 8b Right angle Steps 9a, 9b Separate members C1, C2 Ball center locus

Claims (7)

    An outer joint member in which a plurality of guide grooves extending in the axial direction are formed on the inner peripheral surface, an inner joint member in which a plurality of guide grooves extending in the axial direction are formed on the outer diameter spherical surface, and a guide groove and an inner joint member of the outer joint member Torque transmitting balls arranged one by one on a plurality of ball tracks formed in cooperation with the guide grooves, an outer diameter spherical surface slidably contacting the inner peripheral surface of the outer joint member, and an outer diameter spherical surface of the inner joint member A cage having an inner spherical surface that is in sliding contact and holding a torque transmitting ball, and at a joint operating angle of 0 °, the ball center locus of the guide groove of the outer joint member is a first straight portion parallel to the joint central axis, The ball center locus of the guide groove of the inner joint member is a second straight part parallel to the first straight part within a predetermined range passing through the joint center and perpendicular to the joint central axis. In the predetermined range beyond both ends, the inner joint member An arc portion centered on the center of the radial sphere, the center positions of the inner spherical surface and the outer spherical surface of the cage are offset from the joint center by an equal distance in the opposite direction along the joint central axis, and the ball A constant velocity universal joint characterized in that the outside diameter side window opening size of the window of the cage to be held is smaller than the ball diameter.     2. The constant velocity freely according to claim 1, wherein the outer diameter side portion of the cage window smaller than the ball diameter is constituted by another member which can be retrofitted after the ball is inserted into the window from the outer diameter side. Fittings. While the inner diameter surface of the cage on the joint opening side is a cylindrical surface, a guide ring for slidingly guiding the outer diameter spherical surface of the inner joint member to the cylindrical surface and a retaining ring for retaining the guide ring are mounted. The constant velocity universal joint according to claim 1.     2. The fixed die according to claim 1, wherein the arc part of the ball center locus of the guide groove of the inner joint member is constituted by the ball center locus of the guide groove of another member fitted to the outer periphery of the main body of the inner joint member. Fast universal joint.     Of the plurality of guide grooves of the outer joint member and the inner joint member, only the ball center locus of a part of the guide grooves is constituted by the first straight portion, the second straight portion, and the arc portion of the first guide groove, and the remaining guides. 2. The constant velocity universal joint according to claim 1, wherein the ball center trajectory of the groove is a single circular arc which is entirely overlapped with the center of the joint.   The constant velocity universal joint according to claim 1, wherein an inner peripheral surface of the outer joint member is an inner spherical surface that is in surface-sliding contact with an outer spherical surface of the cage.   The constant velocity universal joint according to claim 1, wherein the inner peripheral surface of the outer joint member is an inner cylindrical surface that is in linear contact with the outer spherical surface of the cage.

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