JP2007139093A - Fixed constant velocity universal joint - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To surely fix a receiving member to a cage while reducing cost of a product by eliminating finishing work in a receiving member press-in part of the cage. <P>SOLUTION: This fixed constant velocity universal joint has an outer member having a spherical inner surface forming a plurality of track grooves, an inner member having a spherical outer surface forming a plurality of track grooves, a ball arranged in a wedge-shaped ball track formed by cooperation of the track grooves of the outer member and the track grooves of the inner member and the cage 40 arranged between the spherical inner surface of the outer member and the spherical outer surface of the inner member and holding the ball, and is formed by pressing the receiving member 56 for receiving pressing force from a pressing part in an inner diameter of the cage 40 by arranging the pressing part on the inner member side for making elastic pressing force act in the axial direction. A flexible part 56e is arranged in an outer peripheral edge part of the receiving member 56. Its flexible part 56e is formed as an overhang part of diametrically expanding a part between both slits 56d in the radial direction by forming two strips of axial directional slits 56d at an interval in a cylindrical part 56c of its receiving member 56. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a fixed type constant velocity universal joint, and more particularly to a fixed type constant velocity universal joint incorporated in a steering device of an automobile.

  Constant velocity universal joints are broadly classified into fixed types that allow only angular displacement between the input and output shafts, and sliding types that allow angular displacement and axial displacement. Each model is selected according to the application and usage conditions. The As a fixed type constant velocity universal joint, a Rzeppa type (hereinafter referred to as “BJ”) and an undercut free type (hereinafter referred to as “UJ”) are widely known.

  Both BJ and UJ are incorporated between an outer ring having a plurality of curved track grooves on the inner periphery, an inner ring having a plurality of curved track grooves on the outer periphery, and a track groove of the outer ring and a track groove of the inner ring. And a cage for holding the ball. The outer ring track groove center is located on the outer ring opening side with respect to the outer ring inner spherical center, and the inner ring track groove center is located on the outer ring rear side with respect to the inner ring outer spherical center, and is offset by an equal distance in the opposite direction in the axial direction. is doing. Thereby, the ball track constituted by the track groove of the outer ring and the track groove of the inner ring has a wedge shape that expands toward the opening side of the outer ring. In BJ, the entire area of each track groove is curved, whereas in UJ, one end of each track groove is in a straight shape parallel to the axis.

  Generally, two or more cardan joints are used for a shaft joint incorporated in an automobile steering device. Since this joint is not uniform at a single unit, it is arranged and used so as to cancel each other's fluctuation components in order to ensure constant velocity. For this reason, there exists a problem that the design freedom of a vehicle is impaired. By using a constant velocity universal joint that can ensure constant velocity at an arbitrary angle as a steering shaft joint, it is possible to increase the design freedom of the vehicle, but the constant velocity universal joint has a large amount of play in the rotation direction, There is a concern that the steering operation feeling near the vehicle will be deteriorated and abnormal noise may be caused. In order to solve this, it has been proposed to provide a preload means inside the constant velocity universal joint to close the track groove clearance (see, for example, Patent Document 1).

The fixed type constant velocity universal joint has a gap between the outer ring track groove and the inner ring track groove due to the function and machining surface, and the inner ring outer sphere, the outer sphere of the cage, the outer ring of the inner ring There is also a gap between the spherical surface and the inner spherical surface of the cage. These clearances refer to the amount of movement when either the inner ring or outer ring is fixed and the other is moved in the radial or axial direction in the neutral state of the joint. Called. These clearances greatly affect the circumferential play (rotational backlash) between the inner and outer rings, and the larger the track groove clearance, the greater the rotational backlash. For this reason, it is unavoidable that the rotation backlash exceeds a certain level. Therefore, this type of fixed type constant velocity universal joint is generally adopted for applications that do not like the rotation backlash, such as an automobile steering device. Not in.
Japanese Patent Laid-Open No. 2003-130082

  By the way, the invention described in the above-mentioned Patent Document 1 is a fixed type constant velocity universal joint for the purpose of filling rotary backlash, and a preload means is provided inside the constant velocity universal joint so as to close the track groove clearance. I have to. In this Patent Document 1, there is provided a preloading means in which a pressing portion for applying an elastic pressing force in the axial direction is provided on the inner member side, and a receiving portion for receiving the pressing force from the pressing portion is provided on the cage side. It is disclosed. In addition, the code | symbol attached | subjected below is described in patent document 1. FIG.

  As one form of the preloading means, a cylindrical housing member 17 is embedded at the shaft end of the shaft 5 coupled to the inner periphery of the inner ring 2 constituting the inner member, and a pressing member is provided inside the housing member 17. 10 and the elastic member 12 are accommodated. The end face of the head portion of the pressing member 10 is formed in a convex spherical shape, and this convex spherical portion functions as the pressing portion 11 that applies an elastic pressing force in the axial direction. On the other hand, a receiving member 14 having a concave spherical surface portion 14 a facing the shaft 5 is attached to the end portion of the cage 4, and the concave spherical portion of the receiving member 14 receives the pressing force from the pressing portion 11. It functions as a receiving portion 15 (see paragraph number [0033] of FIG. 5 and Patent Document 1).

  In the above-mentioned Patent Document 1, the cylindrical housing member 17 is embedded in a recessed portion formed at the shaft end of the shaft 5, and the head portion of the pressing member 10 is a spherical portion of the receiving member 14. 14a is prevented from rotating backlash.

On the other hand, the receiving member 14 is set so that the outer diameter _RS of the receiving member 14 is larger than the inner diameter _RC of the press-fit portion of the retainer 4 as shown in FIGS. As shown in FIG. 9, the receiving member 14 is inserted from an opening end (right side in the figure) opposite to the receiving member press-fitting portion of the retainer 4 and is fixed by being fitted to the press-fitting portion.

  However, if the tightening margin at the press-fitting portion is large, the outer diameter of the retainer 4 is greatly expanded after the receiving member 14 is press-fitted, and further, the spherical portion of the receiving member 14 is greatly deformed, and the outer ring inner spherical surface. There is a risk of deteriorating the operability of the cage 4 inside. Therefore, in order to reduce the tightening margin at the press-fitting portion of the cage 4, the press-fitting portion of the cage 4 is subjected to finishing processing such as grinding or quenching steel cutting. Since such a finishing process increases the cost of the product, if the tightening margin at the press-fitting portion of the cage 4 is reduced without this finishing process, the receiving member may be easily detached from the cage. is there.

  Therefore, the present invention has been proposed in view of the above-mentioned problems, and the object of the present invention is to improve the structure of the preload means disclosed in Patent Document 1 and finish the receiving member press-fitting portion of the cage. An object of the present invention is to provide a fixed type constant velocity universal joint that can reduce processing, reduce the cost of the product, and ensure the fixing of the receiving member to the cage.

  As technical means for achieving the above-mentioned object, the present invention provides an outer member having a spherical inner surface in which a plurality of track grooves are formed, and an inner member having a spherical outer surface in which a plurality of track grooves are formed. A member, a ball disposed on a wedge-shaped ball track formed by cooperation of a track groove of the outer member and a track groove of the inner member, and a spherical inner surface of the outer member and a spherical outer surface of the inner member. And a retainer for holding the ball, provided with a pressing portion on the inner member side for applying an elastic pressing force in the axial direction, and a receiving member for receiving the pressing force from the pressing portion. In the fixed type constant velocity universal joint press-fitted into the inner diameter, at least three or more flexible portions are provided on the outer peripheral edge portion of the receiving member.

  In the present invention, by providing at least three or more flexible portions on the outer peripheral edge portion of the receiving member, the tightening allowance at the press-fitting portion of the cage is reduced without a finishing process such as grinding or hardened steel cutting. However, when the receiving member is press-fitted into the cage, the receiving member is inserted while its flexible portion is deformed, and the edge portion of the deformed flexible portion acts as a stopper against the inner diameter of the cage. The fixing of the receiving member to the cage can be ensured and the receiving member can be prevented from being pulled out of the cage. At the same time, the press-fitted portion of the cage does not need to be manufactured by finishing such as grinding or hardened steel cutting, and the finishing process can be simplified.

  The flexible portion of the receiving member in the above-described configuration has a cylindrical portion extending in the axial direction at the outer peripheral edge portion, and two axial slits are formed in the cylindrical portion at intervals, and a portion between both slits is formed in the diameter. It is desirable to use an overhanging portion whose diameter is expanded in the direction. In this case, when the receiving member is inserted into the cage, the overhanging portion is deformed, and the edge portion of the deformed overhanging portion acts as a stopper with respect to the inner diameter of the cage.

  The flexible part in the above-described configuration can be formed by forming an axial slit by machining, and the flexible part can be formed by a bending process by press working. If it does in this way, a flexible part can be manufactured easily.

  When the fixed type constant velocity universal joint described above is incorporated in a steering apparatus of an automobile, the track groove clearance in the constant velocity universal joint is filled to prevent rotation backlash, and thus a more remarkable effect is exhibited. The automobile steering apparatus may be an electric power steering apparatus that applies a steering assist force by a motor, or may be a hydraulic power steering apparatus.

  According to the present invention, by providing at least three or more flexible parts on the outer peripheral edge of the receiving member, the tightening allowance at the press-fitting part of the cage can be performed without finishing such as grinding or quenching steel cutting. Even if it is made small, it is possible to prevent the receiving member from being detached from the retainer by securing the receiving member to the retainer. At the same time, the press-fitted portion of the cage does not need to be manufactured by finishing such as grinding or hardened steel cutting, and the finishing process can be simplified. As a result, the receiving member can be securely fixed to the cage, the product cost of the fixed type constant velocity universal joint can be reduced, and a highly reliable and inexpensive fixed type constant velocity universal joint can be provided.

  An embodiment of a fixed type constant velocity universal joint according to the present invention will be described in detail. In the following embodiment, a case where the present invention is applied to a Rzeppa type (BJ) which is a kind of a fixed constant velocity universal joint for steering is illustrated, but the present invention is not limited to this, and an undercut free type (UJ) It is also applicable to. Further, the fixed type constant velocity universal joint of the present invention is not limited to steering, but can be used for a drive shaft or a propeller shaft.

  First, a steering device incorporating a fixed type constant velocity universal joint will be briefly described. As shown in FIGS. 7A to 7C, the steering device transmits the rotational motion of the steering wheel 6 to the steering gear 8 through the steering column composed of one or a plurality of steering shafts 2, whereby the tie rod 9 It is made to convert into the reciprocating motion. If the steering shaft 2 cannot be arranged in a straight line in consideration of the space on the vehicle, etc., one or more shaft couplings 1 are arranged between the steering shafts 2 so that the steering gear 8 can be rotated accurately even when the steering shaft 2 is bent. It is possible to transmit exercise. A fixed type constant velocity universal joint is used for the shaft joint 1. The symbol α in FIG. 7B represents the bending angle of the joint, and a large angle at which the bending angle α exceeds 30 ° can be set.

  Next, the fixed type constant velocity universal joint will be described. The fixed type constant velocity universal joint 1 of this embodiment is a Rzeppa type joint (BJ). As shown in FIG. 1, an outer ring 10 as an outer member, an inner ring 20 and a shaft 2 constituting the inner member, and torque are supplied. The transmitting ball 30 and the retainer 40 that supports the ball 30 are constituted as main components. The outer ring 10 is connected to the input shaft or the output shaft, and the inner ring 20 is connected to the output shaft or the input shaft. In this embodiment, the inner member is configured by coupling the shaft 2 to the inner circumference of the inner ring 20 via torque transmission means such as serrations and splines.

  The outer ring 10 has a cup shape opened at one end, and a track groove 14 extending in the axial direction is formed at a circumferentially equidistant position of the spherical inner surface 12. Further, the inner ring 20 is formed with a track groove 24 extending in the axial direction at equal circumferential positions on the spherical outer surface 22. The track groove 14 of the outer ring 10 and the track groove 24 of the inner ring 20 form a pair of ball tracks extending in a wedge shape from one to the other in the axial direction, and one ball 30 is incorporated in each ball track. The cage 40 is slidably interposed between the spherical inner surface 12 of the outer ring 10 and the spherical outer surface 22 of the inner ring 20, and each ball 30 is accommodated in a pocket 46 of the cage 40 and is held at equal intervals in the circumferential direction. Has been.

The outer peripheral surface 42 of the cage 40 is spherically fitted to the spherical inner surface 12 of the outer ring 10, and the inner circumferential surface 44 of the cage 40 is spherically fitted to the spherical outer surface 22 of the inner ring 20. The center of the spherical inner surface 12 of the outer ring 10 and the center of the spherical outer surface 22 of the inner ring 20 coincide with the joint center O. In contrast, the center O ₁ of the track groove 14 of the outer ring 10 and the center O ₂ of the track groove 24 of the inner ring 20 are offset by an equal distance in the opposite directions in the axial direction. For this reason, the ball track formed by the pair of track grooves 14 and 24 has a wedge shape that expands from the back side of the outer ring 10 toward the opening side.

  In this fixed type constant velocity universal joint, the ball 30 guided by the cage 40 is always a plane perpendicular to the bisector of the operating angle regardless of the bending angle, that is, the operating angle between the outer ring 10 and the inner ring 20. The constant velocity of the joint is ensured.

  In this fixed type constant velocity universal joint, a plunger unit 50 is attached to the shaft end of the shaft 2 as shown in FIG. The plunger unit 50 is an assembly body including a ball 53 as a pressing member having a pressing portion 52 at the tip, a compression coil spring 54 as an elastic member, and a case 55 as a housing member for housing the ball 53 and the compression coil spring 54. is there. The compression coil spring 54 serves as a generation source of an elastic force that presses the ball 53 toward the back side of the outer ring 10 (the ball protruding direction).

  In addition, as shown in FIG. 1, a receiving member 56 is attached to the inner end of the outer ring 10 of the cage 40. The receiving member 56 has a lid shape covering the end opening of the cage 40, and as shown in FIGS. 2 (a) and 2 (b), a spherical portion 56a having a partially spherical shape and an enlarged ring formed on the peripheral portion thereof. It is comprised by the diameter flange part 56b and the cylindrical part 56c extended in the axial direction from the enlarged diameter flange part 56b. The inner surface (the surface facing the shaft 2) of the spherical portion 56 a is a concave spherical surface, and this concave spherical surface functions as a receiving portion 58 that receives the pressing force from the pressing portion 52. The enlarged-diameter flange portion 56b and the cylindrical portion 56c, which are the peripheral portions of the receiving member 56, are fixed to the opening end portion of the cage 40 by press-fitting.

  In the above configuration, when the shaft 2 and the inner ring 20 are serrated and the retaining ring 4 is mounted and the both are completely coupled (see FIG. 1), the pressing part 52 of the plunger unit 50 and the receiving part of the receiving member 56 58 come into contact with each other, the ball 53 retracts, and the compression coil spring 54 is compressed. Due to the pressing force from the pressing portion 52, the inner ring 20 integrated with the shaft 2 is axially displaced toward the opening side of the outer ring 10 by an elastic force, and the ball 30 disposed in the track grooves 14 and 24 due to this displacement. Since the track grooves 14 and 24 come into contact with each other, rotation backlash is reliably prevented.

In this fixed type constant velocity universal joint, since the receiving member 56 is fixed to the retainer 40 by press-fitting, the outer diameter R _S1 of the receiving member 56 is press-fitted to the retainer 40 as shown in FIGS. The inner diameter _{RC of the} portion 41 is set larger. The press-fit portion 41 of the cage 40 includes a cylindrical portion 41a having an inner diameter _RC and a reduced-diameter flange portion 41b that is bent radially inward from one end of the cylindrical portion 41a.

As shown in FIG. 5, the receiving member 56 is inserted from the opening end portion (right side in the drawing) opposite to the press-fit portion 41 of the cage 40, and is fitted and fixed to the press-fit portion 41. That is, the diameter-enlarged flange portion 56b of the receiving member 56 is locked by being brought into contact with the diameter-reduced flange portion 41b of the cage 40, and is positioned while being restricted in the axial direction. Further, since the outer diameter R _S1 of the receiving member 56 is set to be larger than the inner diameter _RC of the press-fit portion 41 of the retainer 40, the cylindrical portion 56c of the receiving member 56 is radially directed to the cylindrical portion 41a of the retainer 40. Joining in a state where a pressing force is applied to the outside.

  Here, in this fixed type constant velocity universal joint, as shown in FIGS. 2 (a) and 2 (b) and FIG. 3, flexible portions 56e are provided at three locations of the cylindrical portion 56c which is the outer peripheral edge portion of the receiving member 56. Yes. In this embodiment, the flexible portions 56e are provided at three locations at equal circumferential positions (120 ° intervals) in the cylindrical portion 56c, but may be provided at three or more locations as necessary.

In this embodiment, the flexible portion 56e is a projecting portion in which two axial slits 56d are formed at intervals in the cylindrical portion 56c, and the portion between both slits 56d is expanded radially outward. In the receiving member 56, the outer diameter R _S0 of the cylindrical portion 56c is set to be smaller than or equal to the inner diameter R _C of the press-fit portion 41 of the retainer 40, and the outer diameter R _S1 of the flexible portion 56e is equal to the retainer. It is set to be larger than the inner diameter _RC of the 40 press-fit portions 41.

  The flexible portion 56e can be formed by forming the axial slit 56d by machining. For example, the slit 56d is formed by machining in the cylindrical portion 56c, and the portion between the slits 56d is radially outward. There is a method of expanding the diameter. The flexible portion 56e can be formed by a bending process by press working, and the cylindrical portion 56c is formed by bending the outer peripheral edge portion of the enlarged diameter flange portion 56b by press working when the receiving member 56 is manufactured. There is a method of molding at the same time. This is preferable in that the flexible portion 56e can be easily manufactured.

Thus, by providing the flexible portion 56e in the cylindrical portion 56c of the receiving member 56, even if the tightening allowance at the press-fit portion 41 of the retainer 40 is reduced without finishing processing such as grinding or quenching steel cutting, When the receiving member 56 is press-fitted into the cage 40, the receiving member 56 is inserted while the flexible portion 56e is deformed as shown in FIG. 6, and the edge portion of the deformed flexible portion 56e is the inner diameter of the cage 40. (The outer diameter R _S1 ′ of the flexible part 56e after deformation is smaller than the outer diameter R _S1 of the flexible part 56e before deformation). This ensures that the receiving member 56 is fixed to the retainer 40 and prevents the receiving member 56 from being removed from the retainer 40. At the same time, the press-fit portion 41 of the retainer 40 can be ground or It is not necessary to produce by finishing such as hardened steel cutting, and the finishing process can be simplified.

1 is a cross-sectional view showing an overall configuration of a constant velocity universal joint for steering in an embodiment of a fixed type constant velocity universal joint according to the present invention. (A) is sectional drawing which shows the receiving member of FIG. 1, (b) is the side view. It is a principal part expanded sectional view of Fig.2 (a). (A) is sectional drawing which shows the holder | retainer of FIG. 1, (b) is sectional drawing which shows the receiving member of Fig.2 (a). It is sectional drawing which shows the state which mounted | wore the holder of FIG. 4 (a) with the receiving member of FIG.4 (b). It is a principal part expanded sectional view of FIG. (A) is a top view of a steering apparatus, (b) is a side view of a steering apparatus, (c) is a perspective view of a steering apparatus. (A) is sectional drawing which shows the holder | retainer in the conventional fixed type constant velocity universal joint, (b) is sectional drawing which shows a receiving member. It is sectional drawing which shows the state which mounted | wore the holder of FIG. 8 (a) with the receiving member of FIG.8 (b).

Explanation of symbols

2 Inner member (shaft)
10 Outer member (outer ring)
12 spherical inner surface 14 track groove of outer member (outer ring) 20 inner member (inner ring)
22 spherical outer surface 24 track groove of inner member (inner ring) 30 ball 40 cage 41 press-fitting portion 52 pressing portion 56 receiving member 56c cylindrical portion 56d axial slit 56e flexible portion (overhanging portion)

Claims (5)

  An outer member having a spherical inner surface in which a plurality of track grooves are formed, an inner member having a spherical outer surface in which a plurality of track grooves are formed, a track groove in the outer member, and a track groove in the inner member. An elastic pusher includes a ball arranged on a wedge-shaped ball track formed in cooperation, a cage arranged between the spherical inner surface of the outer member and the spherical outer surface of the inner member, and holding the ball. In the fixed type constant velocity universal joint in which a pressing portion that applies pressure in the axial direction is provided on the inner member side, and a receiving member that receives the pressing force from the pressing portion is press-fitted into the inner diameter of the cage, the receiving member A fixed type constant velocity universal joint characterized in that at least three or more flexible portions are provided on the outer peripheral edge of the fixed constant velocity joint.   The flexible portion has a cylindrical portion extending in the axial direction at the outer peripheral edge of the receiving member, and two axial slits are formed in the cylindrical portion at intervals, and a portion between both slits is radially enlarged. The fixed type constant velocity universal joint according to claim 1, wherein the fixed overhang portion is formed.   The fixed type constant velocity universal joint according to claim 1, wherein the flexible portion is formed by forming an axial slit by machining.   The fixed type constant velocity universal joint according to claim 1, wherein the flexible portion is formed by a bending process by press working.   The fixed constant velocity universal joint according to any one of claims 1 to 4, which is incorporated in a steering device for an automobile.

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