JP2009047236A - Fixed constant velocity universal joint - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fixed constant velocity universal joint capable of realizing the high operating angle without detaching any ball. <P>SOLUTION: The fixed constant velocity universal joint comprises an outer joint member 1, an inner joint member 2, an outer holder 3, an intermediate holder 4 and an inner holder 5 which are assembled between the joint members 1, 2 in a three-layered manner, outer balls 6 rollably interposed in an outer ball track formed between a plurality of guide grooves 1b of the outer joint member 1 and a plurality of guide grooves 4b of the intermediate holder 4, intermediate balls 7 rollably interposed in an intermediate ball track formed between a plurality of guide grooves 3b of the outer holder 3 and a plurality of guide grooves 5b of the inner holder 5, and inner balls 8 rollably interposed in an inner ball track formed between a plurality of guide grooves 4e of the intermediate holder 4 and a plurality of guide grooves 2b of the inner joint member 2. The intermediate ball track is formed in a wedge shape which is alternately expanded in one axial direction and the direction opposite thereto in the circumferential direction. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a fixed type constant velocity universal joint which is a power transmission device used in automobiles and various industrial machines.

  A fixed type constant velocity universal joint is generally used for an axle connecting portion of a drive shaft of an automobile and a shaft bending connecting portion of a steering shaft. As this fixed type constant velocity universal joint, conventionally, a zepper type constant velocity universal joint and an undercut free type (hereinafter referred to as UJ type) constant velocity universal joint are known. The feature of the zepper type is that the ball center trajectory of the guide groove of the outer joint member and the ball center trajectory of the guide groove of the inner joint member are respectively centered on two points that are equidistant from the joint center in the axial direction. It is a meridian of a sphere (see Patent Document 1).

  On the other hand, the UJ type constant velocity universal joint was invented to have a higher operating angle than the Zepper type constant velocity universal joint, and the ball center locus of the guide groove of the outer joint member is the above-mentioned Zepper type meridian. Among these arcs, the opening side portion of the outer joint member is a straight line parallel to the joint axis from the cross section perpendicular to the axis passing through the joint center (see Patent Document 2).

  The Zepper type constant velocity universal joint invented by Zeppa initially has the same arc with the center of the ball of the guide groove of the outer joint member and the center of the ball of the guide groove of the inner joint member centered on the joint center. (See Patent Document 3). The universal joint has a drawback that the rotational position of the cage at an operating angle of 0 ° is not fixed, and in order to compensate for this, the position of the cage is controlled between the inner joint member and the outer joint member. Another part was added (refer to Fig. 1 and Fig. 2 pilot pin K of Patent Document 4).

There is a so-called double offset type of improved Zeppa type constant velocity universal joint. In this double offset type, as shown in FIG. 8A, points O ₁₀₀ and O ₂₀₀ that are separated from the joint center O by an equal distance in the opposite direction in the joint axial direction are formed between the outer joint member 101 and the inner joint member 102, respectively. The center of curvature of each of the two guide grooves 101b and 102b is used. Then, the guide grooves 101b of the two joint members, a ball center trajectory C100, C200 in 102b has a circular arc of the same radius R centered on the center of curvature O _100, O _200.

  Specifically, as shown in FIGS. 8A and 8B, the double offset type constant velocity universal joint is an outer joint in which six curved guide grooves 101b are formed in the axial direction on a spherical inner peripheral surface 101a. A member 101, an inner joint member 102 having a spline (or serration) hole 102c in which six curved guide grooves 102b are formed in the axial direction on a spherical outer peripheral surface 102a, and a guide groove 101b of the outer joint member 101 And the guide groove 102 b of the inner joint member 102 are configured by a torque transmission ball 103 arranged one by one on six ball tracks formed in cooperation with each other, and a cage 104 that holds the torque transmission ball 103. The

The center of curvature of the inner peripheral surface 101 a of the outer joint member 101 and the center of curvature of the outer peripheral surface 102 a of the inner joint member 102 both coincide with the joint center O. In contrast, the curvature center O ₁₀₀ of the guide groove 101b of the outer joint member 101, the curvature center O ₂₀₀ of the guide groove 102b of the inner joint member 102, across the joint center O, opposite directions in the axial direction by an equal distance (In the example shown in the figure, the center O ₁₀₀ is offset to the joint opening end side, and the center O ₂₀₀ is offset to the joint closing end side). Therefore, the ball track formed by the cooperation of the guide grooves 101b and 102b has a wedge shape opened toward one side in the axial direction.

As shown in FIG. 8 (a), when the axes of the joint members 101 and 102 are not angularly displaced, that is, when the two rotational axes are in a straight line, the center of all the torque transmission balls 103 is the joint center. It lies on a plane Y that includes O and is perpendicular to the rotational axis. When the outer joint member 101 and the inner joint member 102 are angularly displaced by an angle θ, the cage 104 causes the torque transmission ball 103 to be arranged on a plane perpendicular to the bisector of the angle θ, thereby Speed is ensured.
US Patent No. 2046584 JP-A-53-65547 U.S. Pat. No. 1,665,280 US Patent No. 2010899

  In the double offset type constant velocity universal joint shown in FIG. 8, when the joint 103 is rotated at a high operating angle, if the ball 103 protrudes outward from the guide groove 101 b of the outer joint member 101, the ball 103 becomes a pocket of the cage 104. It is not possible to prevent it from jumping out radially outward. For this reason, in the conventional double offset type constant velocity universal joint, the ball 103 must be stored in the guide groove 101b of the outer joint member 101, whereby the maximum operating angle of the joint can be suppressed, and at most 48. The limit was around °.

  On the other hand, the UJ type constant velocity universal joint was invented in order to further expand the operating angle of the Zepper type constant velocity universal joint, and in order to extend the position where the ball is removed from the guide groove of the outer joint member, The ball center locus of the guide groove of the member was changed from an arc shape to a linear shape only at the inlet portion of the outer joint member. However, the maximum operating angle of the UJ type constant velocity universal joint was about 52 °.

  Therefore, in view of such circumstances, the present invention intends to provide a fixed type constant velocity universal joint capable of realizing a higher operating angle than the conventional one without dropping the ball.

  The invention according to claim 1 includes an outer joint member in which a plurality of guide grooves extending in the axial direction are formed on a spherical inner peripheral surface, an inner joint member in which a plurality of guide grooves extending in the axial direction are formed in a spherical outer peripheral surface, and a spherical inner and outer surface The outer retainer, the intermediate retainer and the inner retainer, which have a peripheral surface and are incorporated in three layers between the two joint members, and are accommodated in a plurality of pockets formed in the circumferential direction of the outer retainer, and An outer ball rotatably mounted on an outer ball track formed between each guide groove of the outer joint member and a plurality of axially extending guide grooves formed on the spherical outer peripheral surface of the intermediate cage; A plurality of guide grooves extending in the axial direction formed in the spherical inner circumferential surface of the outer cage and a shaft formed in the spherical outer circumferential surface of the inner cage while being housed in a plurality of pockets formed in the circumferential direction of the cage. Multiple guides extending in the direction An intermediate ball that is movably interposed in an intermediate ball track formed between the inner ball cage and a plurality of pockets formed in a circumferential direction of the inner cage, and is accommodated in a spherical inner circumferential surface of the intermediate cage. A plurality of guide grooves extending in the axial direction, and an inner ball that is rotatably mounted on an inner ball track formed between each guide groove of the inner joint member, and the intermediate ball track is arranged in the circumferential direction. It is a fixed type constant velocity universal joint formed in a wedge shape that alternately expands in one axial direction and the opposite direction.

  Thereby, when both rotation axes of the outer joint member and the inner joint member take an operating angle, the distance that each ball rolls in the guide groove is remarkably shortened as compared with the conventional constant velocity universal joint. Therefore, each guide groove can be formed short in the axial direction.

  Further, since the intermediate ball track is formed in a wedge shape, when the joint rotates, a force from the narrow side of the intermediate ball track toward the wide side acts on the intermediate ball in the intermediate ball track. In the first aspect of the invention, the intermediate ball track is formed by alternately enlarging one of the axial directions in the circumferential direction and the opposite direction thereof. Receive. The pressing force from the intermediate ball acts on the intermediate cage, but the pressing forces cancel in each other because they act in opposite directions. Thereby, it can suppress that an intermediate holder | retainer deviates to either one of an axial direction, and can be hold | maintained in an appropriate rotation position.

  According to a second aspect of the present invention, in the fixed type constant velocity universal joint according to the first aspect, the outer ball track and the inner ball track are formed in a wedge shape that expands in the opposite direction in the axial direction.

  Since the outer ball track and the inner ball track expand in the axial direction opposite to each other, forces opposite to each other in the axial direction act on the outer ball and the inner ball arranged in each ball track. Forces opposite to each other in the axial direction also act on the outer cage and the inner cage that respectively hold these balls. The inner peripheral surface of the outer cage and the outer peripheral surface of the inner cage are pressed against the inner and outer peripheral surfaces of the intermediate cage. A pressing force from the outer cage and the inner cage acts on the intermediate cage, but the pushing forces act in opposite directions to cancel each other. Thereby, it can suppress that an intermediate holder | retainer deviates to either one of an axial direction, and can be hold | maintained in an appropriate rotation position.

  According to a third aspect of the present invention, in the fixed type constant velocity universal joint according to the first or second aspect, in a state where the axes of the outer joint member and the inner joint member are in a straight line, the guide groove of the outer joint member Each ball center trajectory of the guide groove on the spherical outer peripheral surface of the intermediate cage, each ball center trajectory of the guide groove on the inner joint member and the guide groove on the spherical inner peripheral surface of the intermediate cage, and the outer cage A pair of ball center trajectories of the guide groove of the inner cage and the guide groove of the inner cage cross each other in a cross section passing through the joint center and orthogonal to the joint axis line, and having a mirror image symmetry about the cross section. It is a circular arc.

  Thereby, each ball | bowl can be hold | maintained on the cross section orthogonal to a joint axis line which passes along the joint center. With the arrangement of the balls, each cage can be rotated at a fixed position when the operating angle is 0 °, and the rotational torque can be stably transmitted.

  According to a fourth aspect of the present invention, in the fixed type constant velocity universal joint according to any one of the first to third aspects, the axial direction of each guide groove of the outer joint member, the inner joint member, and the intermediate cage is orthogonal. In each cross section, each guide groove is constituted by a pair of arc portions that are mirror-symmetric about the joint radial direction line passing through the center in the width direction of each guide groove, and the radius of curvature of the pair of arc portions corresponds to each other. And the center of curvature of the pair of arc portions is disposed on the opposite side from the corresponding arc portion beyond the joint radial line.

  That is, each ball can be brought into contact with the pair of arc portions constituting the guide groove at one point, for a total of two points. With this configuration, when the joint is driven to rotate, the guide groove can easily receive a force in the direction of torque, and the rotational torque can be transmitted efficiently. Further, the ball can easily roll along the guide groove, the contact surface pressure between the ball and the guide groove can be reduced, and the rolling fatigue life or the joint life can be extended.

  A fifth aspect of the present invention is the fixed type constant velocity universal joint according to any one of the first to fourth aspects, wherein the outer ball, the intermediate ball and the inner ball are arranged with a phase shifted in the circumferential direction. It is.

  By preventing the balls from being arranged in a straight line in the joint radial direction, the joint can be reduced in size and weight in the radial direction.

  According to a sixth aspect of the present invention, in the fixed type constant velocity universal joint according to any one of the first to fifth aspects, an even number of four or more intermediate ball tracks are arranged in the circumferential direction.

  As described above, when the joint rotates, forces in opposite directions act on the intermediate balls adjacent in the circumferential direction in the axial direction. In the case of claim 6, since the even number of intermediate balls are arranged in the circumferential direction, the number of intermediate balls directed in one axial direction and the number of intermediate balls directed in the opposite direction are equal. Therefore, it is possible to reliably cancel the forces in opposite directions acting on the intermediate cage.

  According to the fixed type constant velocity universal joint of the present invention, when both rotation axes of the outer joint member and the inner joint member have an operating angle θ other than O °, the distance that each ball rolls in the guide groove is increased. This is shorter than conventional constant velocity universal joints. Therefore, each guide groove can be formed short in the axial direction, and the axial size of the joint can be reduced. As a result, when the joint takes an operating angle θ, the shaft connected to the inner joint member is less likely to interfere with the outer joint member, and the maximum operating angle can be increased. Accordingly, even when the operating angle, for example, the operating angle of the conventional fixed type constant velocity universal joint is 60 °, stable torque transmission can be realized without dropping the ball. Further, since the distance that each ball rolls in the guide groove is shortened, the rolling fatigue life or the joint life can be extended.

  In addition, the force that the intermediate cage receives from the intermediate ball during the rotation of the joint acts in the opposite direction to cancel each other. Can be held in. As a result, a fixed type constant velocity universal joint excellent in constant velocity and operability can be obtained.

Hereinafter, embodiments of the present invention will be described with reference to FIGS. FIG. 1 shows a cross section of a fixed type constant velocity universal joint of the present invention. 2, FIG. 3, and FIG. 4 are AA longitudinal sectional view, B ₁ -B ₁ longitudinal sectional view, B ₂ -B ₂ longitudinal sectional view, and CC longitudinal sectional view in FIG. 5, respectively. . 2 to 5 show a state in which the operating angle is 0 °, and FIG. 7 shows a state in which the longitudinal sections corresponding to FIGS. 2, 3 and 5 are overlapped when the maximum operating angle is taken. Show.

  The fixed type constant velocity universal joint has an outer joint member and an inner joint member, one on the drive side and the other on the driven side. Here, the operating angle is the rotation axis X of the outer joint member and the inner joint. An angle formed by the rotation axis Z of the member. Further, an intersection point O between the rotation axis X and the rotation axis Z is referred to as a joint center. In the fixed type constant velocity universal joint, the joint center O is fixed regardless of the operating angle.

  The fixed type constant velocity universal joint of the present invention includes an outer joint member 1, an inner joint member 2, an outer cage 3, an intermediate cage 4 and an inner cage that are incorporated in three layers between the two joint members 1 and 2. The main component is the container 5 and the outer ball 6, the intermediate ball 7 and the inner ball 8 held by the cages 3, 4 and 5.

  The outer joint member 1 connected to one of two intersecting shafts (not shown) has an inner peripheral surface 1a formed in a spherical shape, and the spherical inner peripheral surface 1a is provided with a guide groove 1b extending in the axial direction. Four are formed at equal intervals in the direction. The outer peripheral surface 2a of the inner joint member 2 is formed in a spherical shape, and four guide grooves 2b extending in the axial direction are formed on the spherical outer peripheral surface 2a at equal intervals in the circumferential direction. Splines or serrations are formed on the inner peripheral surface 2c of the inner joint member 2 for inserting and fitting the shaft 9 which is the other of the two shafts.

  The outer cage 3 has four pockets 3d that are provided at regular intervals in the circumferential direction. Both the outer peripheral surface 3a and the inner peripheral surface 3c of the outer cage 3 are formed in a spherical shape, and four guide grooves 3b extending in the axial direction are formed at equal intervals in the circumferential direction on the spherical inner peripheral surface 3c. . The intermediate retainer 4 and the inner retainer 5 are also provided with four pockets 4d and 5d at equal intervals in the circumferential direction, and the outer peripheral surfaces 4a and 5a and the inner peripheral surfaces of the intermediate retainer 4 and the inner retainer 5, respectively. 4c and 5c are formed in a spherical shape. Further, four guide grooves 4b and 4e extending in the axial direction are formed on both surfaces of the spherical outer peripheral surface 4a and the spherical inner peripheral surface 4c of the intermediate cage 4 at equal intervals in the circumferential direction. Further, four guide grooves 5b extending in the axial direction are formed on the spherical outer peripheral surface 5a of the inner cage 5 at equal intervals in the circumferential direction.

  The spherical inner peripheral surface 1a of the outer joint member 1, the spherical outer peripheral surface 2a of the inner joint member 2, and the spherical inner and outer peripheral surfaces 3a, 3c, 4a, 4c, 5a, and 5c of the cages 3, 4, and 5 These are all concentric spherical surfaces with the joint center O as the center, and the spherical inner and outer peripheral surfaces facing each other are in spherical contact with each other.

  Each pocket 5d of the inner cage 5 accommodates an inner ball 8 for torque transmission. The inner ball 8 is interposed between the opposing guide grooves 2b, 4e of the inner joint member 2 and the intermediate cage 4. The inner ball track is formed so as to roll freely (see FIG. 2). Further, intermediate balls 7 for regulating the positions of the outer cage 3 and the inner cage 5 are accommodated in the respective pockets 4 d of the intermediate cage 4, and the intermediate balls 7 are arranged between the outer cage 3 and the inner cage 5. The intermediate ball track formed between the opposing guide grooves 3b and 5b is rotatably mounted (see FIG. 3 or 4). Similarly, an outer ball 6 for torque transmission is accommodated in each pocket 3d of the outer cage 3, and the outer ball 6 is located between the opposing guide grooves 1b, 4b of the outer joint member 1 and the intermediate cage 4. (See FIG. 5).

  In the outer ball 6 and the inner ball 8 for torque transmission, the inner ball 8 on the inner diameter side has a larger load due to rotational torque, so the ball diameter dimension of the inner ball 8 is set larger than the ball diameter dimension of the outer ball 6. It is preferable. Further, the outer ball 6, the intermediate ball 7, and the inner ball 8 are arranged with a phase shifted in the circumferential direction. In other words, the balls 6, 7, and 8 are not arranged on the same radial line of the joint.

  As shown in the longitudinal sectional views of FIG. 2 to FIG. 5, each ball track formed by opposing arc-shaped guide grooves is formed in a wedge shape gradually spreading toward one side in the axial direction. The inner ball track formed by the opposing guide grooves 2b and 4e of the inner joint member 2 and the intermediate cage 4 shown in FIG. 2 is formed to expand in the left side in the axial direction in FIG.

  The outer ball track formed by the guide grooves 1b and 4b facing each other between the outer joint member 1 and the intermediate cage 4 shown in FIG. 5 is formed to expand to the right in the axial direction in FIG. In this embodiment, the inner ball track of FIG. 2 and the outer ball track of FIG. 5 are formed in a wedge shape that expands in opposite directions.

In FIG. 3 showing the B ₁ -B ₁ longitudinal sectional view of FIG. 1, the intermediate ball track formed by the guide grooves 3 b and 5 b facing each other of the outer cage 3 and the inner cage 5 is the axial direction of FIG. It is enlarged and formed on the right side. On the other hand, in FIG. 4 showing a B ₂ -B ₂ longitudinal sectional view of FIG. 1, the intermediate ball track formed by the guide grooves 3 b and 5 b facing each other of the outer cage 3 and the inner cage 5 is shown in FIG. It expands to the left in the axial direction. In FIG. 1, the intermediate ball track on the B ₁ -B ₁ longitudinal section line and the intermediate ball track on the B ₂ -B ₂ longitudinal section line are arranged adjacent to each other in the circumferential direction. That is, the adjacent ones of the intermediate ball tracks have opposite directions in the axial direction. In other words, the intermediate ball track is formed so as to be alternately enlarged in one axial direction and the opposite direction in the circumferential direction.

Also, the respective centers of curvature of the opposing guide grooves shown in FIGS. 2 to 5 are at positions offset from the joint center O by an equal distance in the axial direction opposite to each other.
Specifically, in FIG. 2, points O ₁ and O _{2 that} are spaced apart (offset) from the joint center O in the joint axial direction in the opposite directions by equal distances are the guide groove 2b of the inner joint member 2 and the intermediate cage. 4 is the center of curvature of each of the inner guide grooves 4e. Accordingly, the ball center locus C1 of the guide groove 2b of the inner joint member 2 is an arc centered on the point O ₁ , and the ball center locus C2 of the guide groove 4e of the intermediate cage 4 is centered on the point O ₂ , The arc has the same radius as the locus C1. That is, these two ball center trajectories C1 and C2 cross each other in a cross section Y passing through the joint center O and orthogonal to the joint axis, and are arranged mirror-symmetrically about the cross section Y.

In FIG. 3, the ball center locus C3 of the guide groove 3b of the outer cage 3 and the ball center locus C4 of the guide groove 5b of the inner cage 5 are offset from the joint center O by an equal distance in the axial direction opposite to each other. Arcs of the same radius centered at the points O ₃ and O ₄ . On the other hand, the ball center locus C3 of the guide groove 3b of the outer cage 3 shown in FIG. 4, the ball center locus C4 of the guide groove 5b of the inner cage 5, and the centers of curvature O ₃ and O ₄ thereof are shown in FIG. The ball center trajectories C3 and C4 and the centers of curvature O ₃ and O ₄ are arranged symmetrically with respect to the cross section Y. The ball center trajectories C3 and C4 in FIGS. 3 and 4 also intersect with each other in the transverse section Y and are arranged mirror-symmetrically about the transverse section Y, as described in FIG.

Further, the ball center locus C5 of the guide groove 1b of the outer joint member 1 and the ball center locus C6 of the outer guide groove 4b of the intermediate cage 4 shown in FIG. 5 are respectively opposite to each other in the axial direction from the joint center O. The arcs have the same radius centered at points O ₅ and O ₆ offset by an equal distance. The ball center loci C5 and C6 also cross each other in a cross section Y passing through the joint center O and orthogonal to the joint axis, and are arranged mirror-symmetrically about the cross section Y.

FIG. 6 is a main part of FIG. 1, and shows a cross section of the guide groove 1 b of the outer joint member 1 sandwiching the outer ball 6 and the guide groove 4 b on the outer peripheral side of the intermediate cage 4. In the figure, a one-dot chain line indicates a joint radial direction line L that passes through the center in the width direction of each of the guide grooves 1 b and 4 b of the outer joint member 1 and the intermediate cage 4. The guide groove 1b of the outer joint member 1 is formed by a pair of circular arc portions 10 and 11 that are mirror-image symmetrical about the joint radial direction line L. The curvature radii R ₁₀ and R ₁₁ of the pair of arc portions 10 and 11 are larger than the radius R ₀ of the outer ball 6. The respective curvature centers O ₁₀ and O ₁₁ of the pair of arc portions 10 and ₁₁ are disposed on the opposite side beyond the joint radial direction line L from the corresponding arc portion. Further, the respective curvature centers O ₁₀ and O ₁₁ are arranged away from the radial line L by an equal distance in the opposite direction in the circumferential direction (left-right direction in FIG. 6). The outer ball 6 makes contact (point contact) at one point (point P ₁₀ and point P ₁₁ ) with each of the circular arc portions 10 and ₁₁ , and makes contact with the guide groove 1b at two points in total (angular contact). .

On the other hand, the outer guide groove 4 b of the intermediate cage 4 is formed symmetrically with the guide groove 1 b of the outer joint member 1 with the outer ball 6 interposed therebetween. Specifically, the guide groove 4b of the intermediate cage 4 is composed of a pair of arc portions 12 and 13 that are mirror-image symmetric about the joint radial direction line L. The radii of curvature R ₁₂ and R ₁₃ of the arc portions 12 and ₁₃ are set larger than the radius R ₀ of the outer ball 6. Further, the centers of curvature O ₁₂ and O ₁₃ of the circular arc portions ₁₂ and ₁₃ are disposed on opposite sides from the corresponding circular arc portions so as to cross the joint radial direction line L and be separated from the joint radial direction line L by an equal distance in the circumferential direction. Has been. By forming the arc portions 12 and 13 in this way, the outer ball 6 also contacts (point contact) with each of the arc portions 12 and 13 at one point (point P ₁₂ and point P ₁₃ ). 4b is contacted at a total of two points (angular contact).

  Moreover, since the cross-sectional shapes of the guide groove 4e inside the intermediate cage 4 sandwiching the inner ball 8 and the guide groove 2b of the inner joint member 2 are the same as those in FIG. 6, illustration and description are omitted. . That is, the inner ball 8 comes into contact with each of the guide grooves 4e and 2b at two points (angular contact).

  Further, the cross-sectional shape of each of the guide grooves 1b, 4b, 4e, and 2b sandwiching the outer ball 6 or the inner ball 8 is, for example, an ellipse that contacts the corresponding ball at two points in addition to the shape shown in FIG. You may form in shapes, such as a Gothic arch and a parabola.

The operation of the fixed type constant velocity universal joint of the present invention will be described below.
In FIG. 1, when a rotational force is applied to the shaft 9, the rotational torque is transmitted to the inner joint member 2 connected to the shaft 9, and then transmitted to the intermediate cage 4 through the inner ball 8. The intermediate cage 4 rotates. Further, the rotational torque of the rotating intermediate cage 4 is transmitted to the outer joint member 1 through the outer ball 6. In this manner, the rotational force is transmitted at a constant speed from the drive shaft connected to the inner joint member 2 to the driven shaft connected to the outer joint member 1.

  When the rotation axis X of the outer joint member 1 and the rotation axis Z of the inner joint member 2 take an operating angle θ, the outer ball 6 has an angle formed by both rotation axes of the outer joint member 1 and the intermediate cage 4. Line up on a plane perpendicular to the bisector. The inner balls 8 are arranged on a plane perpendicular to the bisector of the angle formed by the rotation axes of the intermediate cage 4 and the inner joint member 2. That is, the distance from the center of the outer ball 6 to both rotation axes of the outer joint member 1 and the intermediate cage 4 is equal, and the distance from the center of the inner ball 8 to both rotation axes of the intermediate cage 4 and the inner joint member 2 Are equal. By arranging the balls 6 and 8 at such positions, the rotational torque is transferred from the inner joint member 2 to the intermediate cage 4 through the balls 6 and 8, and from the intermediate cage 4 to the outer joint member 1. Is transmitted at a constant speed.

  FIG. 7 is a view showing a case where the axis X of the outer joint member 1 and the axis Z of the inner joint member have the maximum operating angle. In this case, due to the interference between the joint members 1, 2 and the three cages 3, 4, 5, and the balls 6, 7, 8, the cages 3, 4, The positions of the inner joint member 2 and the inner joint member 2 are regulated with a predetermined inclination angle. If the plane in which the outer ball 6, the intermediate ball 7, and the inner ball 8 are arranged is referred to as a joint plane S, T, U, in this embodiment, each joint plane S, T, U passes through the joint center O. From the cross section Y orthogonal to the axis X of the outer joint member 1, the outer joint member 1 is in a position inclined 15 °, 30 °, and 45 ° clockwise. At this time, the maximum operating angle formed by the axis Z of the inner joint member 2 and the axis X of the outer joint member 1 is 60 °.

  In the conventional fixed type constant velocity universal joint as shown in FIG. 8, when the maximum operating angle is set to 60 °, the joint plane on which the balls 103 are arranged passes through the joint center O and is orthogonal to the axis X of the outer joint member 101. It is estimated that it is necessary to incline 30 ° clockwise or counterclockwise from the cross section Y (not shown). That is, the ball 103 moves 30 ° along the guide grooves 101b and 102b. In contrast, according to the present invention, when the maximum operating angle is 60 °, the balls 6, 7, and 8 arranged in the joint planes S, T, and U move along the corresponding guide grooves at a distance of 15 °. Therefore, the length in the axial direction of each guide groove can be made shorter than the guide groove of the conventional fixed type constant velocity universal joint.

  Further, since the intermediate ball track is formed in a wedge shape, when the joint rotates, a force from the narrow side of the intermediate ball track toward the wide side acts on the intermediate ball 7 in the intermediate ball track. In the above embodiment, the intermediate ball track is formed by alternately enlarging one of the axial directions in the circumferential direction and the opposite direction, so that the adjacent intermediate balls 7 exert forces in the opposite directions to each other. receive. The pressing force from the intermediate ball 7 acts on the intermediate cage 4, but the pressing force cancels because it acts in the opposite direction. Thereby, it can suppress that the intermediate | middle holder | retainer 4 deviates to either one of an axial direction, and can be hold | maintained in an appropriate rotation position.

  Further, in order to surely cancel the force received by the intermediate cage 4 from the intermediate ball 7 during the rotation of the joint, it is desirable to form the same number of intermediate ball tracks enlarged in opposite directions. Accordingly, it is preferable to arrange an even number of four or more intermediate ball tracks.

  Also, since the outer ball track and the inner ball track are each formed in a wedge shape, when the joint rotates, a force from the narrower side of the ball track to the wider side acts on the balls in each ball track. Thereby, the outer cage 3 that holds the outer ball 6 and the inner cage 5 that holds the inner ball 8 are pressed against the intermediate cage 4.

  In the present invention, in order to cancel the pressing force applied to the intermediate cage 4 by the outer cage 3 and the inner cage 5, the outer ball track and the inner ball track are enlarged in opposite directions in the axial direction. That is, the outer ball 6 interposed in the outer ball track and the inner ball 8 interposed in the inner ball track try to move in opposite directions. Then, the pressing forces of the outer cage 3 and the inner cage 5 with respect to the intermediate cage 4 also act in opposite directions to cancel each other. Thereby, it can suppress that the intermediate | middle holder | retainer 4 deviates to either one of an axial direction, and can be hold | maintained in an appropriate rotation position.

  As mentioned above, although one Embodiment of this invention was described, this invention is not limited to the above-mentioned embodiment, Of course, a various change can be added in the range which does not deviate from the summary of this invention.

It is a cross-sectional view of a fixed type constant velocity universal joint according to the present invention. It is AA longitudinal cross-sectional view of FIG. A B ₁ -B ₁ longitudinal sectional view of FIG. _{2 is} a B ₂ -B ₂ longitudinal sectional view of FIG. 1. FIG. It is CC longitudinal cross-sectional view of FIG. It is a principal part cross-sectional view of FIG. It is a longitudinal section showing the state where the fixed type constant velocity universal joint of the present invention took the maximum operating angle. It is a figure which shows the conventional fixed type constant velocity universal joint, Comprising: (a) is the longitudinal cross-sectional view, (b) is the cross-sectional view.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Outer joint member 1a Inner peripheral surface 1b Guide groove 2 Inner joint member 2a Outer peripheral surface 2b Guide groove 3 Outer cage 3b Guide groove 3c Inner peripheral surface 3d Pocket 4 Intermediate cage 4a Outer peripheral surface 4b Guide groove 4c Inner peripheral surface 4d Pocket 4e Guide groove 5 Inner cage 5a Outer peripheral surface 5b Guide groove 5d Pocket 6 Outer ball 7 Intermediate ball 8 Inner ball 10 Arc portion 11 Arc portion 12 Arc portion 13 Arc portion

Claims (6)

  An outer joint member having a plurality of guide grooves extending in the axial direction on the spherical inner peripheral surface, an inner joint member having a plurality of guide grooves extending in the axial direction on the spherical outer peripheral surface; The outer retainer, the intermediate retainer and the inner retainer assembled in a three-layer shape between the joint members, and each guide groove of the outer joint member is accommodated in a plurality of pockets formed in the circumferential direction of the outer retainer. And an outer ball that is movably mounted on an outer ball track formed between a plurality of axially extending guide grooves formed on a spherical outer peripheral surface of the intermediate cage, and formed in a circumferential direction of the intermediate cage A plurality of guide grooves extending in the axial direction formed on the spherical inner peripheral surface of the outer cage and a plurality of guide grooves extending in the axial direction formed on the spherical outer peripheral surface of the inner cage. Formed between An intermediate ball rotatably mounted on the intermediate ball track and accommodated in a plurality of pockets formed in a circumferential direction of the inner cage, and extend in an axial direction formed on a spherical inner circumferential surface of the intermediate cage. A plurality of guide grooves and an inner ball that is movably interposed on an inner ball track formed between the guide grooves of the inner joint member, and the intermediate ball track extends in one circumferential direction across the intermediate ball track. And a fixed type constant velocity universal joint characterized by being formed in a wedge shape that alternately expands in the opposite direction.   2. The fixed type constant velocity universal joint according to claim 1, wherein the outer ball track and the inner ball track are formed in a wedge shape that expands in the axial direction in opposite directions. In a state where each axis of the outer joint member and the inner joint member is in a straight line,
The ball center locus of each of the guide groove of the outer joint member and the guide groove of the spherical outer peripheral surface of the intermediate cage,
The ball center locus of each of the guide groove of the inner joint member and the guide groove of the spherical inner peripheral surface of the intermediate cage,
And the ball center locus of each of the guide groove of the outer cage and the guide groove of the inner cage,
The fixed mold according to claim 1 or 2, wherein each of the cross sections intersects each other in a cross section that passes through the joint center and is orthogonal to the joint axis, and is a pair of arcs that are mirror-symmetric with respect to the cross section. Fast universal joint.   In the transverse cross section orthogonal to the axial direction of each guide groove of the outer joint member, the inner joint member and the intermediate cage, each guide groove is mirror-symmetric about the joint radial line passing through the center in the width direction of each guide groove. And a radius of curvature of the pair of arc portions is set to be larger than a radius of the corresponding ball, and a center of curvature of the pair of arc portions is set from the corresponding arc portion to the joint. 4. The fixed type constant velocity universal joint according to claim 1, wherein the fixed type constant velocity universal joint according to claim 1 is disposed on the opposite side beyond the radial line. 5.   5. The fixed type constant velocity universal joint according to claim 1, wherein the outer ball, the intermediate ball, and the inner ball are arranged with a phase shifted in a circumferential direction. 6.   The fixed type constant velocity universal joint according to any one of claims 1 to 5, wherein an even number of four or more intermediate ball tracks are arranged in the circumferential direction.

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