JP2007120546A - Fixed type constant velocity universal joint and its assembling method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an easy-to-assemble fixed type constant velocity universal joint having a great torque load capacity. <P>SOLUTION: On the corner-side inner face of an mouth portion 10a of an outer ring, a spherical supporting portion 18 is formed around a joint center O where the center lines of two connected axes of the joint cross each other. On an inner peripheral face 46 of a cage 40 contacting an inner ring 20, a spherical portion 46a and a cylindrical portion 46b are formed which is located on the opening side of the mouth portion of the outer ring and which is located on the corner side of the mouth portion of the outer ring, respectively. The axial length of the cylindrical portion 46a is set to allow the axial movement of the inner ring 20 over a predetermined range and to allow the storage of the circumscribed circle of a torque transmitting ball 30 in the outside contour of the cage 40 when the inner ring 20 is at an axially moving stroke end. At the front end of a shaft 50 which is inserted in an axial connection hole formed in the center of the inner ring 20 for transmitting torque to the inner ring 20, a supported face 50a is formed which has the same curvature as the spherical supporting portion 18 for slide contact with the spherical supporting portion 18 in all range of the operating angle of the joint. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a fixed type constant velocity universal joint and a method for assembling the fixed type constant velocity universal joint. The present invention relates to a fixed type constant velocity universal joint that is slidably contacted in the entire range of corners and an assembling method thereof.

  Fixed type constant velocity universal joints allow only angular displacement between the connected drive side and driven side shafts, and are used in axle connection parts of automobile drive shafts and power transmission systems of various industrial machines. . As a type of the 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.

  A zeppa type constant velocity universal joint which is a fixed type constant velocity universal joint includes an outer ring, an inner ring, a ball and a cage. A plurality of curved ball grooves are formed at equal intervals on the inner spherical surface of the outer ring and the outer spherical surface of the inner ring. The ball is assembled between the outer ring ball groove and the inner ring ball groove, and the cage is assembled between the outer ring and the inner ring. The UJ type constant velocity universal joint was developed for the purpose of higher operating angle than the Zepper type constant velocity universal joint, and the ball center locus of the ball groove of the outer ring is the center of the arc of the above Zepper type meridian. The section on the opening side of the outer ring is a straight line parallel to the joint axis from the cross section perpendicular to the axis passing through (see Patent Document 1).

  When the cage is assembled to the outer ring of such a fixed type constant velocity universal joint, in the fixed type constant velocity universal joint described in Patent Document 1, the cage is first placed in the outer ring, and then the inner ring is placed inside the cage. Passing through the outer ring, place it on the back side of the normal position, and in that state, insert the torque transmission ball (hereinafter simply referred to as “ball”) into the cage pocket from the inside, and then place the inner ring in the normal position. Finally, a member for supporting the inner ring in the axial direction is inserted and fixed to the outer ring.

The fixed type constant velocity universal joints described in Patent Document 2 and Patent Document 3 have a shape that allows the inner ring to pass in the coaxial direction through the inner diameter portion of the cage opposite to the large end face opening of the outer ring. The outer ring is also opened on the side opposite to the large end face opening so that the inner ring can pass in the coaxial direction. The assembly method is to put the cage in the outer ring, put the ball into the cage pocket from the inside, and then insert the inner ring through the outer ring and cage from the large end face opening side of the outer ring. A member that supports the inner ring is inserted into the opening portion on the opposite side and fixed to the outer ring.
JP-A-6-193645 JP-T-2004-521295 JP 2004-116666 A

  In the fixed type constant velocity universal joint described in Patent Document 1, the track groove of the inner ring is shallow due to the assembly method, and the torque load capacity is reduced. That is, after inserting the cage into the outer ring, it is necessary to set the outer diameter of the inner ring smaller than the inner diameter of the cage so that the inner ring can be inserted inside the cage and pushed into the bottom of the outer ring. Here, since the outer diameter of the intermediate shaft fitted to the inner ring is a specified value, the track groove of the inner ring becomes shallower when the outer diameter of the inner ring is reduced. As a result, there arises a problem that the torque load capacity is reduced.

  Further, the fixed type constant velocity universal joint described in Patent Document 1 has a structure in which the outer spherical surface of the inner ring is supported in the axial direction by the concave spherical surface of the bottom member disposed on the bottom of the outer ring. Since the concave spherical surface of the bottom member supporting the inner ring in the axial direction is located in a relatively narrow range including the joint central axis, it is difficult to maintain constant velocity at a large operating angle, and vibration There is a problem that the amount of heat generation and wear increases due to a large relative displacement between the concave spherical surface of the bottom member and the outer spherical surface of the inner ring.

  In addition, the work of putting the ball from the inside of the outer ring and the cage is complicated, and the work efficiency in the assembly process is poor.

  Even in the fixed type constant velocity universal joints described in Patent Document 2 and Patent Document 3, the work of putting the ball from the inner side of the outer ring and the cage is complicated. In addition, since a large opening for passing the inner ring is required on the side opposite to the large end face opening of the outer ring, the outer diameter of this portion must be increased. As a result, not only is the weight increased, but the gap between the outer diameter and the inner diameter is narrowed. For example, when applied to a wheel bearing device for a drive wheel, a connecting portion (stem shaft) with a wheel hub and the hollow outer ring It is difficult to make a structure to connect In addition, the wheel side of the outer ring, that is, the opposite side of the large end surface has a different shape depending on the vehicle type, but it is difficult to apply when a small diameter is required.

  A main object of the present invention is to provide a fixed type constant velocity universal joint that solves the above-described problems, is easy to assemble, and is lightweight and compact.

  In order to solve the above-mentioned problem, the invention of claim 1 is characterized in that an outer ring in which a plurality of ball grooves extending in the axial direction are formed on the inner spherical surface of the bowl-shaped mouth portion opened at one end, and a plurality of extending in the axial direction on the outer spherical surface. Torque transmission by interposing between the inner ring formed with the ball groove, the torque transmission ball incorporated between the ball groove of the outer ring and the ball groove of the inner ring, and the inner spherical surface of the outer ring and the outer spherical surface of the inner ring. In a fixed type constant velocity universal joint provided with a cage for holding a ball in an axial direction, a spherical support portion centering on a joint center where a center line of a joint two-axis of the joint intersects with an inner surface on the back side of the outer ring mouth portion. Formed on the inner peripheral surface of the cage in contact with the inner ring, a spherical portion located on the opening side of the outer ring mouse part and a cylindrical part located on the back side of the outer ring mouse part, and the axial length of the cylindrical part is , And allow the axial movement of the inner ring over a predetermined range Furthermore, when the inner ring is at the stroke end of the axial movement, the circumscribed circle of the torque transmitting ball is set to a length that can be accommodated in the outer contour of the cage, and the axial connection hole formed at the center of the inner ring A fixed type constant velocity universal joint in which a supported surface is formed at the tip of a shaft that is inserted and transmits torque to the inner ring, and has a curvature that is the same as that of the spherical support portion and that is in sliding contact with the spherical support portion over the entire range of joint operating angles. is there.

  According to a second aspect of the present invention, in the first aspect of the invention, the inner ring is received when the shaft is inserted into the inner ring connecting hole adjacent to the outer edge portion of the spherical support portion on the inner surface on the back side of the outer ring mouth portion. This is a fixed type constant velocity universal joint having a seat.

  When the seat for receiving the inner ring is not formed, it is necessary to form a jig engaging part on the inner ring and restrain the movement of the inner ring when inserting the shaft by the jig. The inner ring shaft length becomes longer and the processing cost increases. Of course, the inner ring restraint by the jig is not easy to work and complicated. In the present invention, the above-mentioned inconveniences are all eliminated by forming an inner ring receiving seat on the outer ring.

  According to a third aspect of the invention, in the first or second aspect of the invention, a circlip having an elastic expansion force is fitted into an annular groove formed on the outer peripheral surface of the shaft, and the circlip is expanded in the inner ring connecting hole. An expanded diameter portion that opens and fits is formed, and the circlip is slidably contacted with the inner peripheral surface of the inner ring connecting hole with a predetermined frictional force while the shaft is being inserted into the inner ring, and the shaft is inserted into the inner ring. The fixed constant velocity universal joint is configured such that the circlip is expanded at the enlarged diameter portion to prevent the shaft from being pulled out at the completion position.

  According to a fourth aspect of the present invention, in the invention according to any one of the first to third aspects, the side surface on the retaining side of the enlarged-diameter portion is a right-angled surface perpendicular to the axis of the inner ring or a shaft acting on the circlip. This is a fixed type constant velocity universal joint having an inclined surface inclined in a direction in which the circlip is expanded by force.

  When an axial force in the pulling direction is applied to the shaft, the circlip tends to come out of the inner ring diameter-enlarged portion, but the circlip is prevented from coming out by making the radial surface of the enlarged diameter portion inclined as described above. Be certain. Even if the radial surface of the enlarged diameter portion is a vertical surface, a sufficient escape prevention effect can be obtained.

  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 inner ring, the cage and the torque transmission ball are a temporarily assembled unit capable of unit handling.

  According to a sixth aspect of the present invention, in the invention according to any one of the first to fifth aspects, a projection having an inner diameter smaller than the outer diameter of the outer spherical surface of the inner ring is provided on the cylindrical portion of the inner circumferential surface of the cage, and the stroke end of the inner ring is formed by the projection. Is a fixed type constant velocity universal joint.

  The invention of claim 7 is the invention according to any one of claims 1 to 6, wherein the minimum inner diameter of the opening of the outer ring mouth portion is the diameter of the corner formed by the outer spherical surface of the cage and the side wall facing the axial direction of the pocket. This is a larger fixed type constant velocity universal joint.

  The invention of claim 8 is the invention according to any one of claims 5 to 7, wherein the circumscribed circle diameter of the ball in the temporary assembly unit is a corner portion formed by the outer spherical surface of the cage and the side wall facing the axial direction of the pocket. It is a fixed type constant velocity universal joint with a diameter or less.

  According to a ninth aspect of the present invention, in any one of the fifth to eighth aspects, the distance from the bottom of the ball groove of the inner ring to the corner formed by the inner spherical surface of the cage and the side wall of the spherical portion of the pocket in the temporary assembly unit. Is a fixed type constant velocity universal joint made smaller than the ball diameter.

  The invention of claim 10 is a method for assembling the fixed type constant velocity universal joint according to any one of claims 1 to 9, wherein the inner ring is put in a cage, and the phase of the ball groove of the inner ring and the pocket of the cage is matched. This is a method of assembling a fixed type constant velocity universal joint in which a ball is inserted into a pocket from the outside to obtain a temporary assembly unit of an inner ring, a cage and a torque transmission ball, and the temporary assembly unit is inserted into an outer ring.

  The invention of claim 11 is the invention of claim 10, wherein the step of shifting the phase of the ball grooves of the inner ring and the outer ring in the temporary assembly unit, the step of inserting the temporary assembly unit into the outer ring in the coaxial direction, A method of assembling a fixed type constant velocity universal joint, comprising: a step of matching the phases of the ball grooves; and a step of causing the inner ring and the ball to occupy regular positions by moving the inner ring in the axial direction.

  According to a twelfth aspect of the present invention, in the eleventh aspect of the invention, a circlip having an elastic expansion force is fitted into an annular groove formed on the outer peripheral surface of the shaft, and the circlip is expanded in the inner ring connecting hole. The circlip is slid in contact with the inner peripheral surface of the inner ring connecting hole with a predetermined friction force during the insertion of the shaft into the inner ring, and the inner ring of the inner ring accompanying the insertion of the shaft is formed. This is a method of assembling a fixed type constant velocity universal joint in which movement is prevented by a seat.

  According to a thirteenth aspect of the present invention, in the invention of the twelfth aspect, the pulling force applied to the shaft is transmitted to the inner ring through the frictional force to move the inner ring in the axial direction, thereby positioning the inner ring and the ball in a normal position. This is a method for assembling a fixed type constant velocity universal joint.

  The invention according to claim 14 is the invention according to claim 12 or 13, wherein after the pulling force is applied to the shaft to occupy the normal position on the inner ring and the ball, the shaft is inclined to be exposed to the outer ring mouth portion opening side. The shaft is inserted in a state where the inner ring cannot be tilted by pressing one end face of the inner ring with a jig, and the circlip is expanded at the enlarged-diameter portion at the position where the shaft is completely inserted into the inner ring, thereby fixing the shaft. This is an assembly method of a constant velocity universal joint.

  According to the present invention, assembly of a fixed type constant velocity universal joint, that is, assembly of components is facilitated. One is that the temporary assembly unit of the inner ring, the cage and the ball can be unit-handled, and the other is that the workability is good because the ball is inserted from the outside when making the temporary assembly unit.

  In addition, the fixed type constant velocity universal joint of the present invention inserts the temporary assembly unit from the opening on the large end surface of the outer ring, and therefore closes the side opposite to the large end surface of the outer ring as compared with those of Patent Documents 2 and 3. Even in the case of a structure (cup-shaped outer ring) or an opening structure, the inner diameter can be reduced. Therefore, the outer diameter of this portion can be reduced, and it becomes easy to reduce the weight and respond to changes in the outer shape depending on the vehicle type. Moreover, the design of the connection part with a wheel hub becomes easy by thickening of the part.

  A temporary assembly unit that can handle the inner ring, cage, and ball as a unit, and a combination of the temporary assembly unit and the outer ring to form a fixed type constant velocity universal joint, the outer ring has various shapes according to the application. A common temporary assembly unit can be used. For example, even if the outer ring outer shape or the shape of the connecting shaft with the wheel differs depending on the vehicle type or the like, only the temporary assembly unit can be used, which greatly contributes to cost reduction.

  Since the spherical support portion on the inner surface on the inner side of the outer ring mouse portion is a spherical surface that is continuous with the inner spherical surface of the outer ring mouse portion, these can be formed simultaneously in a single process using a common machine tool, and the outer ring manufacturing cost can be reduced.

  Since the tip supported surface of the shaft is continuously slidably contacted with the spherical support portion on the inner surface of the outer ring mouth portion in the full range of joint operating angles, the inner ring is stabilized in the axial direction by the outer ring spherical support portion via the shaft. As a result of smooth support, the occurrence of vibrations and abnormal noise is suppressed and constant speed is maintained, as well as the amount of heat generation and wear on the outer ring of the inner ring is reduced, and sufficient torque load capacity is obtained. It is done.

  Since the inner surface of the outer ring mouse part is the same spherical surface support part as the outer ring inner spherical surface, it is not necessary to separately provide another member or recess for supporting the inner ring on the inner side of the outer ring mouse part. The axial length of the joint can be saved to reduce the joint weight and cost.

  Since the shaft or inner ring is tilted and the shaft is pushed into the inner ring connecting hole in a state where the tilt of the inner ring is restrained, a jig engaging portion or the like is formed on the inner ring to restrain the inner ring in the axial direction. There is no need, and the production cost of the inner ring can be reduced accordingly.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a longitudinal section of a UJ (undercut free) type fixed constant velocity universal joint. As shown in the figure, the fixed type constant velocity universal joint includes an outer ring 10, an inner ring 20, a ball 30, a cage 40 and a shaft 50 as main components.

  The outer ring 10 includes a mouse portion 10a and a stem portion 10b. In this embodiment, the stem portion 10b has a serration portion 10b1 and a screw portion 10b2. As shown in FIGS. 2 and 3, the mouse portion 10a has a bowl-like shape opened at one end, and its inner peripheral surface (hereinafter referred to as “inner spherical surface”) is connected to two joints of the joint, that is, the stem portion 10b. The inner spherical surface 12 has a radius R centering on the joint center O where the center line of the shaft 50 intersects. A plurality (eight in this case) of ball grooves 14 extending in the axial direction are formed on the inner spherical surface 12 at equal intervals in the circumferential direction. As shown in FIG. 1, a concave spherical support 18 is formed on the inner surface of the mouse portion 10a. The spherical support portion 18 is a concave spherical surface having a radius R with the joint center O as the center. Therefore, the outer ring inner spherical surface 12 and the spherical support portion 18 are the same spherical surface and can be formed in one step by a machine tool. The tip supported surface 50a of the shaft 50 inserted into the spline hole 26 serving as a connecting hole at the center of the inner ring 20 is in sliding contact with the spherical support portion 18 over the entire range of joint operating angles. An annular recess 19 is formed on the inner surface of the outer ring mouth portion 10a adjacent to the outer edge portion of the spherical support portion 18 and adjacent to the outer ring inner spherical surface 12 or the rear end portion of the ball groove 14. A seat 19 a that is perpendicular to the outer ring axis is formed on the inner surface of the recess 19. The spherical support 18 of the outer ring 10 and the tip supported surface 50a of the shaft 50 are provided with a hardened surface layer by heat treatment in order to improve wear resistance.

As shown in FIG. 2, a chamfer 16 a that contacts the shaft 50 at the maximum operating angle of the shaft 50 coupled to the inner ring 20 is continuously formed in the peripheral edge of the outer ring 10 on the opening side edge of the mouse portion 10 a. As shown in FIGS. 2 and 3, a cylindrical portion 16b is formed between the chamfer 16a and the opening side of the inner spherical surface 12 of the mouse portion 10a. The cylindrical portion 16b forms a minimum inner diameter C ₁ of the mouth section 10a opening, mutual distance between the opposite side of the cylindrical portion 16b which face each other across the outer ring center is minimized inside diameter C _1.

The inner ring 20 has a spherical shape as shown in FIGS. 1 and 4, and a plurality of, here, eight ball grooves 24 extending in the axial direction are formed on the partial spherical outer peripheral surface (hereinafter referred to as “outer spherical surface”) 22. They are formed at equal intervals in the direction. In FIG. 4, reference signs A ₁ and A ₂ indicate the outer diameter of the outer spherical surface 22 of the inner ring 20 and the minimum projected diameter on the central cross section of the outer spherical surface 22, respectively. The inner ring 20 is coupled to the shaft 50 through a through spline hole 26 as a connection hole so that torque can be transmitted. The tip of the shaft 50 is a convex spherical supported surface 50a having the same curvature as the spherical support portion 18 of the outer ring mouse portion 10a. The tip of the shaft 50 penetrates the spline hole 26 and projects to the opposite side of the inner ring 20. An enlarged diameter portion 20 d that is larger than the inner diameter of the spline hole 26 and reaches the tooth bottom of the spline hole 26 is formed on the inner peripheral edge of the spline hole 26. The radial surface of the enlarged diameter portion 20d is configured by a vertical surface 20d1 perpendicular to the axis of the inner ring 20 in consideration of ease of machining (see enlarged view (I) in FIG. 1). However, the radial surface of the enlarged diameter portion 20d may be the inclined surface 20d2 as necessary (see the enlarged view (II) in FIG. 1). The inclination direction of the inclined surface 20d2 is an inclination direction in which the circlip 52 is expanded by an axial force acting on the circlip 52 (θ <90 °). An annular groove 27 is formed at an intermediate position in the axial direction of the spline portion 50 b of the shaft 50. The circular groove 27 is fitted with a circlip 52 having a circular or rectangular cross section having an elastic spreading force. The gap between the annular groove 27 and the circlip 52 is made as small as possible. A tapered step portion 50c is formed on the proximal end side of the spline portion 50b. The taper step portion 50c contacts the taper step portion 20a on the inner ring 20 side when the shaft 50 is completely inserted into the spline hole 26 (see FIG. 1).

As shown in FIG. 1, the center of curvature O ₁ of the ball groove 14 of the outer ring 10 and the center of curvature O ₂ of the ball groove 24 of the inner ring 20 are offset from the joint center O by an equal distance f in the axial direction. Therefore, the ball grooves 14 and 24 of the inner and outer rings 10 and 20 that form a pair have a wedge shape that expands toward the large end face side opening of the outer ring 10.

The fixed type constant velocity universal joint of this embodiment has no undercut in the ball grooves 14 and 24 (undercut free). That is, the ball groove 14 of the outer ring 10 is composed of a circular arc bottom 14a parallel straight bottom 14b to the axis positioned on the large end face positioned on the small end face side to the center of curvature O ₁ as a boundary. Similarly, the ball groove 24 of the inner ring 20 has an arc bottom 24a located on the large end face side of the outer ring 10 and a straight bottom 24b parallel to the axis located on the small end face side of the outer ring 10 with the center of curvature O ₂ as a boundary. Composed.

The cage 40 is interposed between the inner spherical surface 12 of the outer ring 10 and the outer spherical surface 22 of the inner ring 20. A plurality of, here, eight pockets 42 are arranged in the circumferential direction of the cage 40. The pocket 42 has a substantially rectangular shape, but the circumferentially opposed surface is an arc surface substantially equal to the curvature of the ball 30. The outer spherical surface 44 of the cage 40 is in contact with the inner spherical surface 12 of the outer ring 10. As shown in FIGS. 5 and 6, the diameter B ₂ of the corners 41 and 43 formed by the outer spherical surface 44 of the cage 40 and the side walls facing the axial direction of the pocket 42 is the outer diameter of the outer spherical surface 44 of the cage 40. smaller than B _1. Diameter B ₂ is are smaller than the inner diameter _{C 1} of the cylindrical portion 16b of the outer ring 10 (B _{2 <C} 1). This is a dimensional relationship required when the cage 40 is inserted coaxially with the outer ring 10. However, even if the dimensional relationship is slightly reversed such as C ₁ <B ₂ , it is not impossible to insert the cage 40 by shrink fitting or pinching it to the outer ring 10.

Here, even if the diameter B ₂ (diameter on the cage insertion side) of the portion indicated by reference numeral 41 in FIG. 5B is slightly larger, it can be entered by slightly tilting the shaft 50 from the same axis, but the diameter B of the portion indicated by reference numeral 43. ₂ (diameter opposite to the cage insertion side) requires the above dimensional relationship (B ₂ <C ₁ ). It is also possible to provide a portion to be cut to reduce the diameter B ₂ such as chamfering the corners 41 and 43 of the cage 40. If the diameter B ₂ can be reduced, the inner diameter C ₁ of the cylindrical portion 16b of the outer ring 10 can also be reduced, and thereby the range of the outer ring inner spherical surface 12 that guides the cage outer spherical surface 44 can be expanded to the opening side. It becomes less and is constant speed, durability, etc.

As can be seen from FIG. 5, the inner peripheral surface 46 of the cage 40 is configured by a combination of a spherical portion 46 a and a cylindrical portion 46 b that are smoothly continuous with each other at the axial center (coincident with the joint center O in FIG. 1). That is, the large end surface side of the outer ring 10 from the center in the axial direction is a spherical surface portion 46a that contacts the outer spherical surface 22 of the inner ring 20 and supports the inner ring 20 in the radial direction and the axial direction, and the small end surface of the outer ring 10 from the axial center. The side is a cylindrical portion 46b that contacts the inner ring outer spherical surface 22 and supports the inner ring 20 in the radial direction. The cylindrical portion 46b is necessary for retracting the inner ring 20 from the normal position in the axial direction during the assembly process (see FIG. 8). Accordingly, the accuracy may be rough except for a narrow range in which the inner ring 20 is supported in the radial direction at the normal position. In FIG. 8, the inner diameter of the spherical surface portion 46a is indicated by B ₃ , and the inner diameter of the cylindrical portion 46b is indicated by B ₄ .

A protrusion 48 protruding toward the inner diameter side is provided at the end of the cage cylindrical portion 46b. As shown in FIG. 8, when the inner ring 20, the ball 30 and the cage 40 are used as a temporary assembly unit, the projection 48 is used to prevent the inner ring 20 from falling off, in other words, the stroke end of the inner ring 20 moving in the axial direction. It functions as a prescribed stopper (see FIGS. 8 and 9). Therefore, the inner diameter B _{5 of the} protrusion 48 is set smaller than the outer diameter A ₁ of the outer spherical surface 22 of the inner ring 20.

  The ball groove 14 of the outer ring 10 and the ball groove 24 of the inner ring 20 make a pair, and a ball 30 is incorporated between each pair of ball grooves 14, 24. One ball 30 is accommodated in each pocket 42 of the cage 40. The cage 40 acts so that all the balls 30 are positioned on the bisector of the angle formed by the outer ring 10 and the inner ring 20, that is, the operating angle of the joint, whereby the constant velocity of the joint is maintained. .

Next, a method for assembling the fixed type constant velocity universal joint having the above-described configuration, that is, a procedure for assembling the components including the outer ring 10, the inner ring 20, the ball 30, and the cage 40 will be described. First, as shown in FIG. 7, the inner ring 20 is inserted into the cage 40 with the axes orthogonal to each other. At this time, the magnitude relationship (A ₂ <B ₅ ) between the minimum projected diameter A ₂ (FIG. 4) in the central cross section of the outer spherical surface 22 of the inner ring 20 and the inner diameter B ₅ (FIG. 8) of the projection 48 of the cage 40 is expressed. Use. Then, the inner ring 20 is turned so that the two axes coincide with each other to be coaxial. If the diameter difference (B ₅ -A ₂ ) is small, it may be pushed in the same direction from the beginning.

  The inner ring 20 is moved in the axial direction within the cylindrical portion 46b of the cage 40, and the outer spherical surface 22 of the inner ring 20 is brought into contact with the projection 48 of the cage 40, so that both are in the positional relationship shown in FIG. At this time, the inner ring 20 stops at the position where the outer spherical surface 22 hits the protrusion 48 of the cage 40, that is, the position retracted by the distance indicated by the symbol X from the normal position by the stopper function of the protrusion 48 described above.

As shown in FIGS. 9 and 10, the ball 30 is inserted into the pocket 42 from the outside in a state where the phase of the ball groove 24 of the inner ring 20 and the phase of the pocket 42 of the cage 40 are matched. Push the ball 30 to abut against the ball grooves 24 of the inner ring 20, ball circumscribed circle diameter _{D 1} is the diameter B ₂ (FIG. 5, FIG. 6) of the corner 41, 43 of the pocket 42 of the cage 40 to be equal to or less than. In other words, when the inner ring 20 is at the stroke end of the axial movement, the circumscribed circle of the ball is set within the outer contour of the cage 40.

  When eight balls are used, the ball PCD is larger than the ball diameter compared to those using seven or fewer balls, so that the amount of ball jumping out from the outer spherical surface of the cage is small. In order to obtain a state where the ball is pushed in the temporary assembly unit, the pushing amount of the ball in the radial direction can be small. In addition, since the ball PCD is large with respect to the ball diameter, it is easy to ensure serration inside the inner ring, and it is easy to secure a spherical surface portion on the opposite side of the inner ring from the large end surface of the outer ring.

At this time, indicated at D ₂ in FIG. 9, the distance from the bottom of the ball groove 24 of the inner ring 20 to the corner portion formed between the spherical portion side wall of the spherical portion 46a and the pocket 42 of the cage 40 is smaller than the ball diameter When the dimensions are set, the ball 30 does not fall off to the inner diameter side, unit handling is possible, and handling becomes very easy. The dimensional relationship depends on the position (X) of the protrusion 48 of the cage 40 described above with reference to FIG. Normally, there is an interference between the ball 30 and the pocket 42, so that it is difficult for the ball 30 and the pocket 42 to drop off.

  Next, as shown in FIG. 11, the temporary assembly unit of the inner ring 20, the cage 40 and the ball 30 is inserted from the opening of the outer ring 10. As shown in FIG. 12, this insertion is performed with the phase of the ball groove 14 of the outer ring 10 and the ball groove 24 of the inner ring 20 being shifted by α / 2, where α is the angle between adjacent balls. As a result, the outer spherical surface 44 of the cage 40 comes into contact with the inner spherical surface 12 of the outer ring 10, and at that time, the end surface 20b of the inner ring 20 comes into contact with the seat 19a of the outer ring 10, resulting in the state shown in FIG.

  The ball 30 of the temporary assembly unit only needs to be within the outer contour of the cage 40 when passing through the cylindrical portion 16b of the outer ring 10, and after passing through this, the radius along the inner spherical surface 12 of the outer ring 10 is sufficient. Can move outward in the direction. Here, the axial position of the seat 19a of the outer ring 10 with which the peripheral edge of the end face 20b of the inner ring 20 abuts is more advantageous in reducing the axial size of the joint. Therefore, after the ball 30 passes through the outer ring cylindrical portion 16b and before the outer spherical surface 44 of the cage 40 hits the inner spherical surface 12 of the outer ring 10, the peripheral surface of the end surface 20b of the inner ring 20 hits the seat 19a of the outer ring 10, and that of the inner ring 20 As a result of preventing the above movement, if the ball 30 jumps outward in the radial direction as the cage 40 further advances to the inner side of the outer ring mouth portion 10a, the seat 19a can be positioned on the larger end face side. .

  Next, as shown in FIG. 13, the shaft 50 is inserted into the spline hole 26 of the inner ring 20 in the direction of arrow A with the axes of the outer ring 10 and the inner ring 20 aligned. At this time, the circlip 52 attached to the shaft 50 is in sliding contact with the spline hole 26 of the inner ring 20 and pushes the inner ring 20 to the inner side of the joint, but the inner ring 20 does not move because it is received by the seat 19a. When the shaft 50 is fully inserted into the spline hole 26 of the inner ring 20, the tip supported surface 50 a of the shaft 50 comes into contact with the spherical surface support portion 18.

  From this state, as shown in FIGS. 12 and 14, the phases of the temporary assembly units (20, 30, 40) and the outer ring 10 are shifted by α / 2 to match the phases of the ball grooves 14, 24 of the inner and outer rings 10, 20. Let With the phases of the ball grooves 14 and 24 matched, the shaft 50 is moved in the direction of arrow B (drawing direction) in FIG. At this time, since the circlip fitted in the annular groove of the shaft 50 is in sliding contact with the inner peripheral surface of the connecting hole of the inner ring 20 with a predetermined frictional force, the inner ring 20 is also pulled by the shaft 50 and the arrow B It moves to the opening side of the outer ring 10 in the direction. Due to the movement of the inner ring 20, the outer spherical surface 22 of the inner ring 20 comes into contact with the spherical portion 46 a of the cage 40. Further, as the inner ring 20 moves in the axial direction, the ball 30 moves outward in the radial direction, and the inner ring 20 and the ball 30 occupy the normal position.

  Next, as shown in FIG. 15, the shaft 50 and the inner ring 20 are largely inclined with respect to the outer ring 10. Thereby, the one end surface of the inner ring 20 protrudes to the opening side of the outer ring mouse part 10a. In this state, the inner ring outer spherical surface 22 is in contact with the spherical portion 46a of the cage inner peripheral surface 46 on one side and is restrained in the inner and outer directions of the joint, but on the opposite side, the inner ring outer spherical surface 22 is in the cage inner peripheral surface 46. The movement of the joint in the outer direction is restrained, but the movement in the inner (back side) direction is free.

  Therefore, in the state of FIG. 15, if the shaft 50 is inserted into the spline hole 26 without restraining the inner ring 20 at all, only the opposite side of the inner ring 20 tends to tilt toward the joint back side due to the frictional force of the circlip 52. . As a result, the inner ring 20 is inclined with respect to the shaft 50, and the spline fitting surfaces of both the inner ring 20 are twisted, making it impossible to insert the shaft 50.

  In order to prevent such a twisting phenomenon, the present invention uses a bottomed cylindrical main block 60 and a bowl-shaped sub-block 61 which can accommodate and position the outer ring 10 as shown in FIG. The stem 10 b is inserted into the hole 60 a at the bottom of the main block 60, and the outer ring 10 is accommodated in the main block 60. The outer ring 10 is positioned by bringing the outer circumferential surface of the outer ring 10 into contact with the inner circumferential surface of the main block 60. The sub block 61 is detachably attached to the opening side of the main block 60 using bolts or screws. The front end side surface 63 of the arm portion 62 of the sub block 61 is pressed against one end surface of the inner ring 20. By pressing the arm portion 62, the outer spherical surface 22 of the inner ring 20 is pressed against the cage spherical surface portion 46a, and the tilting of the inner ring 20 is prevented in combination with the restriction by the flat side surface 63 of the arm portion 62. When the shaft 50 is inserted in the direction of the arrow C in the spline hole 26 of the inner ring 20 with the inner ring 20 prevented from tilting in this way, the inner ring 20 is not tilted, that is, on the spline fitting surface with the shaft 50. The shaft 50 can be inserted without twisting. At this time, the circlip 52 slides on the inner peripheral surface of the spline hole 26 of the inner ring 20.

  When the shaft 50 is inserted to the end and the tip supported surface 50a abuts on the inner peripheral surface (the inner spherical surface 12 and the spherical support portion 18) of the outer ring mouth portion 10a, at the same time, the taper step portion 50c of the shaft 50 becomes the inner ring 20. And the circlip 52 reaches the enlarged diameter portion 20d and elastically expands (see enlarged views (I) and (II) in FIG. 1). The expanded circlip 52 is located at the overlapping portion of both the spline teeth of the inner ring 20 and the shaft 50 and is restrained by the vertical surface 20d1 (or the inclined surface 20d2) of the expanded diameter portion 20d while being fitted in the annular groove 27. The Therefore, in this state, the shaft 50 cannot be inserted and removed from the inner ring 20. When an axial force in the pulling direction is applied to the shaft 50, the circlip 52 tends to come out from the inner ring enlarged diameter portion 20d. For this reason, if the radial surface of the enlarged diameter portion 20d is the inclined surface 20d2, the circlip 52 can be prevented from coming out. The radial surface of the enlarged diameter portion 20d is not necessarily the inclined surface 20d2, but at least the vertical surface 20d1 is necessary. If the inclined surface 20d2 is inclined to the opposite side, the circlip 52 can be easily removed.

  Next, the sub block 61 is removed from the main block 60, and then the outer ring 10 is taken out from the main block 60. Thereafter, the shaft 50 is moved in the direction of arrow D in FIG. 16, and the shaft 50 is returned to the coaxial state with the stem portion 10b as shown in FIG. 1, thereby completing the assembly of the fixed type constant velocity universal joint.

  As shown in FIG. 1, the fixed type constant velocity universal joint of the present invention supports the tip supported surface 50a of the shaft 50 and the outer spherical surface 22 of the inner ring 20 in the axial direction by the spherical surface supporting portion 18 provided on the outer ring 10. Since the outer spherical surface 22 of the inner ring 20 is supported in the radial direction by the inner diameter portions 46a and 46b of the cage 40, the amount of heat generation and wear on the outer spherical surface 22 can be reduced, and sufficient torque load capacity can be secured. It is possible to prevent the occurrence of vibrations and abnormal noise and maintain the constant velocity.

  The present invention is not limited to the embodiments described and illustrated above, and various modifications can be made without departing from the scope of the claims. For example, although the illustrated embodiment exemplifies one using eight torque transmitting balls, it is also possible to use six torque transmitting balls.

  As a method for assembling the fixed type constant velocity universal joint, as described above, the inner ring 20, the ball 30 and the cage 40 are assembled as a temporary assembly unit, and the mouse part 10a and the stem part 10b of the outer ring 10 are separated. If it is a hollow outer ring mouse, it can also be assembled by inserting the cage 40 into the outer ring 10 in the coaxial direction and then assembling the inner ring 20 and the ball 30. Furthermore, as described above, the present invention can be applied to an assembling method in which the cage is inserted into the outer ring in a coaxial direction, and the cage is inserted perpendicularly to the outer ring.

The longitudinal cross-sectional view of the fixed type constant velocity universal joint which shows embodiment of this invention. The principal part longitudinal cross-sectional view of an outer ring | wheel. The side view of the opening side of an outer ring | wheel. The end view of an inner ring. The longitudinal cross-sectional view of a cage. A side view of the cage. Explanatory drawing which shows the process in which an inner ring | wheel is integrated in a cage. The principal part longitudinal cross-sectional view which shows the positional relationship of an inner ring | wheel and a cage. The longitudinal cross-sectional view which shows the process in which a ball | bowl is integrated in the subassembly of an inner ring | wheel and a cage, and it is set as a temporary assembly unit. FIG. 10 is a right side view of the subassembly of FIG. 9. The principal part longitudinal cross-sectional view which shows the process in which the inner assembly of an inner ring | wheel, a cage, and a ball | bowl is assembled in an outer ring | wheel. FIG. 5 is an end view of the temporarily assembled unit assembled in the outer ring with the phase of the ball groove shifted by a half pitch. The longitudinal cross-sectional view of the state which inserted the shaft in the temporary assembly unit in an outer ring | wheel. FIG. 13 is an end view similar to FIG. 12 in a state where the phases of the ball grooves of the inner and outer rings are matched. The longitudinal cross-sectional view which shows the state which makes an inner ring inclineable with a jig | tool, and inserts in an inner ring in the state which inclined the shaft. The longitudinal cross-sectional view of the state which inserted the shaft in the inner ring and connected with the inner ring.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Outer ring 10a Mouse | mouth part 10b Stem part 10b1 Serration part 10b2 Thread part 12 Inner spherical surface 14, 24 Ball groove 14a Arc bottom 14b Straight bottom 16a Chamfer 16b Cylindrical part 17 Projection edge 18 Spherical support part 19 Recess 19a Seat 20 Inner ring 20a Tapered step Portion 20b end surface 20d expanded diameter portion 20d1 vertical surface 20d2 inclined surface 22 outer spherical surface 24 ball groove 24a arc bottom 24b straight bottom 26 spline hole 27 annular groove 29 recess 30 ball 40 cage 41, 43 corner 42 pocket 44 outer spherical surface 46a inner sphere Portion 46b cylindrical portion 48 protrusion 50 shaft 50a tip supported surface 50b spline portion 50c taper step portion 52 circlip 60 main block 60a hole 61 sub block 62 arm portion 63 tip side surface

Claims (14)

An outer ring in which a plurality of ball grooves extending in the axial direction are formed on the inner spherical surface of the bowl-shaped mouth portion opened at one end, an inner ring in which a plurality of ball grooves extending in the axial direction are formed on the outer spherical surface, and a pair of outer rings A fixed type equipped with a torque transmission ball incorporated between the ball groove and the ball groove of the inner ring, and a cage that is interposed between the inner spherical surface of the outer ring and the outer spherical surface of the inner ring and holds the torque transmission ball in the axial direction. In constant velocity universal joints,
On the inner surface on the back side of the outer ring mouse part, a spherical support part is formed around the joint center where the center line of the coupling two axes of the joint intersects.
A spherical portion located on the opening side of the outer ring mouse portion and a cylindrical portion located on the back side of the outer ring mouse portion are formed on the inner peripheral surface of the cage in contact with the inner ring, and the axial length of the cylindrical portion is defined as the axis of the inner ring. Set the length to allow the circumscribed circle of the torque transmitting ball to be accommodated in the outer contour of the cage when the inner ring is at the end of the axial movement stroke,
The shaft is inserted into an axial connecting hole formed at the center of the inner ring and transmits torque to the inner ring, and is in sliding contact with the spherical support portion over the entire range of joint operating angles with the same curvature as the spherical support portion. Fixed type constant velocity universal joint with a supported surface.   The fixed type constant velocity universal according to claim 1, wherein a receiving seat for receiving the inner ring when the shaft is inserted into the inner ring connecting hole is formed adjacent to the outer edge portion of the spherical support portion on the inner surface of the outer ring mouth portion. Fittings.   A circlip having an elastic expansion force is fitted into an annular groove formed on the outer peripheral surface of the shaft, and a diameter-expanded portion is formed in the inner ring connecting hole so that the circlip is expanded and fitted. During the insertion of the circlip, the circlip is brought into sliding contact with the inner peripheral surface of the inner ring connecting hole with a predetermined frictional force, and the circlip is expanded at the enlarged diameter portion at the insertion completion position of the shaft with respect to the inner ring. The fixed type constant velocity universal joint according to claim 1 or 2, wherein the shaft is prevented from being pulled out.   The side surface on the retaining side of the enlarged-diameter portion is a right-angled surface perpendicular to the axis of the inner ring, or an inclined surface inclined in a direction in which the circlip expands due to an axial force acting on the circlip. To 3 fixed constant velocity universal joints.   The fixed type constant velocity universal joint according to any one of claims 1 to 4, wherein the inner ring, the cage and the torque transmission ball are temporary assembled units capable of unit handling.   6. The fixed type constant velocity universal joint according to claim 1, wherein a projection having an inner diameter smaller than the outer diameter of the outer spherical surface of the inner ring is provided on the cylindrical portion of the inner circumferential surface of the cage, and the stroke end of the inner ring is defined by the projection.   The fixed constant velocity universal joint according to any one of claims 1 to 6, wherein a minimum inner diameter of the opening of the outer ring mouse portion is larger than a diameter of a corner portion formed by an outer spherical surface of the cage and a side wall facing the axial direction of the pocket.   The fixed constant velocity universal joint according to any one of claims 5 to 7, wherein a circumscribed circle diameter of the ball in the temporary assembly unit is equal to or less than a diameter of a corner portion formed by an outer spherical surface of the cage and a side wall facing the axial direction of the pocket. .   The fixed type according to any one of claims 5 to 8, wherein the distance from the bottom of the ball groove of the inner ring in the temporary assembly unit to the corner formed by the inner spherical surface of the cage and the spherical side wall of the pocket is smaller than the ball diameter. Fast universal joint.   A method for assembling a fixed type constant velocity universal joint according to any one of claims 1 to 9, wherein an inner ring is put in a cage, and a ball groove of the inner ring and a pocket of the cage are matched, and a ball is put into the pocket from the outside of the cage. Thus, a method for assembling a fixed type constant velocity universal joint in which a temporary assembly unit of an inner ring, a cage and a torque transmission ball is obtained and the temporary assembly unit is put in an outer ring.   A step of shifting the phases of the ball grooves of the inner ring and the outer ring in the temporary assembly unit, a step of coaxially placing the temporary assembly unit in the outer ring, a step of matching the phases of the ball grooves of the inner ring and the outer ring, and an axial direction of the inner ring The method for assembling a fixed type constant velocity universal joint according to claim 10, further comprising the step of moving the inner ring and the ball to occupy regular positions.   A circlip having an elastic expansion force is fitted into an annular groove formed on the outer peripheral surface of the shaft, and a diameter-expanded portion is formed in the inner ring connecting hole so that the circlip is expanded and fitted. The circlip is slidably brought into contact with the inner peripheral surface of the inner ring connecting hole with a predetermined friction force during the insertion of the inner ring, and the movement of the inner ring accompanying the insertion of the shaft is prevented by a seat. Assembly method for fixed constant velocity universal joints.   The fixed constant velocity universal according to claim 12, wherein the pulling force applied to the shaft is transmitted to the inner ring through the frictional force so that the inner ring is moved in the axial direction so that the inner ring and the ball occupy regular positions. How to assemble a joint.   After the pulling force is applied to the shaft and the inner ring and the ball occupy the normal position, the shaft is tilted and the inner ring exposed to the opening side of the outer ring mouse part is pressed with a jig so that the inner ring cannot be tilted. 14. The method of assembling a fixed type constant velocity universal joint according to claim 12 or 13, wherein the shaft is inserted, and the circlip is expanded at the enlarged diameter portion at a position where the shaft is completely inserted into the inner ring to prevent the shaft from being removed.

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