JP2022148756A - Outside joint member for slidable constant velocity universal joint, and manufacturing method therefor - Google Patents

Abstract

To facilitate management of force for preventing internal components from coming off from an outside joint member, while reducing a manufacturing cost of a slidable constant velocity universal joint.SOLUTION: A pre-finishing track groove 5' is formed by forging. Then, by machining the pre-finishing track grooves 5', a rolling body guide surface 5a parallel to an axial direction, and a raised part 5b provided on a joint opening side of the rolling body guide surface 5a are formed.SELECTED DRAWING: Figure 4

Description

TECHNICAL FIELD The present invention relates to an outer joint member for a sliding constant velocity universal joint and a manufacturing method thereof.

A constant velocity universal joint has an outer joint member and an inner joint member arranged on the inner periphery of the outer joint member, and the outer joint member and the inner joint member are connected via rolling elements such as balls and rollers. transmit torque. The constant velocity universal joint includes a fixed constant velocity universal joint that allows angular displacement between the outer joint member and the inner joint member but does not allow axial displacement, and an angle between the outer joint member and the inner joint member. They are broadly classified into sliding constant velocity universal joints that allow not only displacement but also axial displacement.

In a sliding type constant velocity universal joint, in order to prevent the internal parts including the inner joint member and the rolling elements from falling out from the open end of the outer joint member when it is attached to the vehicle body, etc., the internal parts are retained. It is common to provide structure. For example, in Patent Document 1 below, a raised portion formed by crimping is formed at the open end of the track groove of the outer joint member, and a roller is brought into contact with this raised portion to prevent the internal parts from coming off. A structure is shown that performs

JP 2020-133894 A

However, since the protuberances formed by the crimping process as described above have variations in shape, the pull-out preventing force of the internal parts including the roller (the force required to pull out from the inner circumference of the outer joint member) varies. . For this reason, in order to guarantee the pull-out preventing force of the internal parts, it is necessary to take into consideration the variations due to the shape of the raised portion as described above, and it becomes difficult to manage the pull-out preventing force.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to facilitate management of a force for preventing an internal component from coming off from an outer joint member of a sliding constant velocity universal joint.

By the way, in the sliding constant velocity universal joint, in order to allow the rolling elements (rollers and balls) to roll smoothly in the track grooves of the outer joint member, an appropriate gap is set between the track grooves and the rolling elements. There is a need. However, since the outer joint member is generally formed by forging and then heat treated, the dimensional accuracy of the track grooves is not so high. On the other hand, the outer peripheral surface of the rolling element is finished with high accuracy by grinding. Therefore, it is common to prepare a plurality of types of rolling elements having different diameters in advance and select and assemble the rolling elements that match the dimensions of the track groove of the outer joint member. However, in this case, since it is necessary to form multiple types of rolling elements and stock them, manufacturing costs are high in the case of small-lot production.

Therefore, if the rolling element guide surfaces of the track grooves are machined and finished with high precision, the number of man-hours increases, but the need to prepare multiple types of rolling elements is eliminated. The present invention is characterized in that the machining for forming the rolling element guide surface forms the protuberance provided at the open end of the track groove. That is, if the protuberance is formed by machining that enables high-precision processing, variation in the shape of the protuberance can be suppressed, and the pull-out preventing force can be controlled with high precision. In this case, the processing cost of the raised portion is higher than when forming by caulking, but by forming the raised portion by machining the rolling element guide surface, the cost increase of the entire outer joint member can be suppressed. can.

The present invention, which has been made based on the above findings, has a plurality of track grooves for accommodating rolling elements formed on the inner peripheral surface, and allows angular displacement and axial displacement between the rolling elements and the inner joint member via the rolling elements. In the outer joint member for a sliding constant velocity universal joint that transmits rotational torque while
The track groove has a rolling element guide surface parallel to the axial direction and a raised portion provided on the joint opening side of the rolling element guide surface,
The rolling element guide surface and the raised portion are formed by machining.

Further, the present invention, which has been made based on the above findings, has a plurality of track grooves for accommodating rolling elements formed on the inner peripheral surface, and is provided with an angular displacement and an axial displacement between the rolling elements and the inner joint member via the rolling elements. In a method for manufacturing an outer joint member for a sliding constant velocity universal joint that transmits rotational torque while allowing
a step of forming pre-finishing track grooves by forging;
A step of machining the pre-finishing track groove to form a rolling element guide surface parallel to the axial direction and a raised portion provided on the joint opening side of the rolling element guide surface.

The raised portion may be partially machined to leave a forged surface. Alternatively, the entire protuberance may be formed by machining.

In the process of assembling the sliding constant velocity universal joint, rolling elements are inserted into the track grooves of the outer joint member from the opening side. For this reason, it is preferable that the rolling elements can be attached to and detached from the track groove over the raised portion while elastically deforming the region near the opening end including the raised portion of the outer joint member. In this case, the rolling elements can be easily inserted into the track grooves, and the rolling elements can be easily removed from the track grooves during repair or maintenance.

When the rolling elements are pushed into the track grooves of the outer joint member, by providing the track groove chamfered portion between the open end face and the raised portion of the outer joint member, the contact between the rolling elements and the outer joint member causes the rolling elements to move. It is possible to prevent the outer peripheral surface from being damaged. This track groove chamfered portion can be formed, for example, by forging the track groove. Alternatively, the track groove chamfers can be formed by machining as described above. In this case, since the chamfered portion of the track groove can be finished with high precision, it becomes easier to manage the pressing amount when incorporating the rolling elements into the track groove.

As described above, according to the present invention, it is possible to facilitate management of the force to prevent the internal component from coming off from the outer joint member while suppressing the manufacturing cost of the sliding constant velocity universal joint.

It is an axial cross-sectional view of a tripod type constant velocity universal joint. Fig. 2 is a cross-sectional view of the tripod type constant velocity universal joint in the direction orthogonal to the axis; It is the front view which looked at the outer joint member of the said tripod type constant velocity universal joint from the axial direction. 4 is a cross-sectional view taken along the line XX of FIG. 3; FIG. It is a cross-sectional view of the outer joint member before machining. It is a sectional view of the outer joint member concerning other embodiments. It is the front view which looked at the outer joint member which concerns on other embodiment from the axial direction. FIG. 8 is an axial cross-sectional view of the outer joint member of FIG. 7; Figure 8 is a cross-sectional view of the outer joint member of Figure 7 prior to machining; Fig. 4 is a front view of the outer joint member of the double offset type constant velocity universal joint as seen from the axial direction; FIG. 11 is an axial cross-sectional view (YY cross-sectional view of FIG. 10) of a double offset type constant velocity universal joint having the outer joint member of FIG.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the drawings.

As shown in FIGS. 1 and 2, a tripod type constant velocity universal joint 1 according to an embodiment of the present invention includes an outer joint member 2, a tripod member 3 as an inner joint member, and rollers 4 as rolling elements. Prepare. In addition, the “axial direction” in the description of the present invention means the axial direction of the outer joint member 2 (horizontal direction in FIG. 1).

The outer joint member 2 is a cup-shaped member having an opening at one end. Three axially extending track grooves 5 are formed on the inner peripheral surface of the outer joint member 2 at regular intervals in the circumferential direction. The track groove 5 has a pair of side surfaces 51 facing each other, and a large-diameter cylindrical surface 52 connecting outer diameter ends of the pair of side surfaces 51 . A side surface 51 of the track groove 5 is provided with a roller guide surface 5a as a rolling element guide surface. The roller guide surface 5a is a surface parallel to the axial direction, and more specifically, a curved surface ( for example, a cylindrical surface). A small-diameter cylindrical surface 2 d is provided on the inner peripheral surface of the outer joint member 2 between the track grooves 5 in the circumferential direction. A chamfered portion 2 c is formed at the open end of the small-diameter cylindrical surface 2 d of the outer joint member 2 . The maximum operating angle of the tripod type constant velocity universal joint 1 is defined by the contact of the shaft 8 with the chamfered portion 2c.

The tripod member 3 has a boss portion 6 provided with a central hole 6a and three leg shafts 7 protruding radially from the boss portion 6 . A female spline 6b that can be fitted to a male spline 8b formed at the end of the shaft 8 is formed in the central hole 6a of the boss portion 6. As shown in FIG. The end portion of the shaft 8 is inserted into the center hole 6a, and the male spline 8b and the female spline 6b are fitted to each other, so that the shaft 8 and the tripod member 3 are integrally rotatably connected. A snap ring 9 is attached to the end of the shaft 8 protruding from the center hole 6 a to prevent the shaft 8 from slipping out of the tripod member 3 in the axial direction.

A roller unit 14 including rollers 4 and the like is attached to each leg shaft 7 of the tripod member 3 . The roller unit 14 includes a roller 4 as an outer ring, an inner ring 10 disposed inside the roller 4 and fitted on the leg shaft 7, and a large number of needle-like rollers interposed between the roller 4 and the inner ring 10. It is composed of rollers 11 . The roller 4, inner ring 10, and needle roller 11 are assembled together by washers 12 and 13 so as not to separate from each other.

The rollers 4 are arranged in the track grooves 5 of the outer joint member 2 . As the rollers 4 roll along the roller guide surfaces 5 a of the track grooves 5 , the inner parts including the roller units 14 and the tripod members 3 are axially displaced with respect to the outer joint member 2 . The tripod member 3 is also allowed to be tilted with respect to the axis of the outer joint member 2 . In the illustrated example, the roller unit 14 can be tilted with respect to the axis of the leg shaft 7 because the cross section of the leg shaft 7 is formed in a substantially elliptical shape. The roller unit 14 functions as a torque transmission member that transmits rotational torque between the tripod member 3 and the outer joint member 2 when the tripod member 3 rotates with the rotation of the shaft 8 .

The tripod type constant velocity universal joint 1 according to this embodiment includes a boot 15 for sealing the opening of the outer joint member 2 . The boot 15 comprises a large-diameter end portion 15a, a small-diameter end portion (not shown), and a bellows portion 15c connecting the large-diameter end portion 15a and the small-diameter end portion. A large-diameter end portion 15 a of the boot 15 is attached by being tightened by a boot band 16 to a boot mounting portion 2 b formed on the opening end side of the outer diameter surface of the outer joint member 2 . The small-diameter end portion of the boot 15 is attached to a boot attachment portion (not shown) formed on the outer diameter surface of the shaft 8 by tightening it with another boot band.

A retaining structure for preventing the internal components (the roller unit 14 and the tripod member 3) from coming off from the outer joint member 2 will be described below.

As shown in FIGS. 3 and 4, the opening end of the side surface 51 of the track groove 5 of the outer joint member 2 is provided with a raised portion 5b for retaining the internal component. The protuberance 5b is provided smoothly and continuously on the joint opening side (upper side in FIG. 4) of the roller guide surface 5a. The raised portion 5b protrudes toward the center of the track groove 5 (the side closer to the opposing roller guide surface 5a) than the roller guide surface 5a. Specifically, the raised portion 5b has an inclined surface that is displaced toward the center of the track groove 5 toward the joint opening side. The raised portion 5b is provided over the entire length of the opening edge of the side surface 51 of the track groove 5 in the extending direction. That is, one end of the raised portion 5b reaches the large-diameter cylindrical surface 52, and the other end of the raised portion 5b reaches the chamfered portion 2c. In addition, the raised portion 5b may be provided in a part of the opening edge of the side surface 51 of the track groove 5 in the extending direction (for example, in an intermediate region excluding both ends in the extending direction).

In this embodiment, one raised portion 5 b is provided on each roller guide surface 5 a of each track groove 5 . A gap W1 between the pair of roller guide surfaces 5a provided in each track groove 5 is slightly larger than the outer diameter D of the roller 4 (see FIG. 4). A gap W2 between the pair of raised portions 5b provided in each track groove 5 is slightly smaller than the outer diameter D of the roller 4. As shown in FIG. In addition, the amount of protrusion of each raised portion 5b may not be the same. The protrusion amount of the raised portion 5b may be varied for each outer joint member 2, for each track groove 5, or for each raised portion 5b.

When assembling the internal part to the outer joint member 2, the roller 4 of the internal part is pushed from the open end of the track groove 5 toward the inner part of the joint (lower side in FIG. 4). At this time, since the gap W2 between the pair of protuberances 5b is smaller than the outer diameter D of the roller 4, the roller 4 contacts the pair of protuberances 5b, and the insertion of the roller 4 is temporarily restricted. However, by pushing the roller 4 into the track groove 5 against the restricting force of the protuberances 5b, the region near the open end of the outer joint member 2 is elastically deformed, and the distance between the protuberances 5b facing each other is pushed. By spreading, the roller 4 gets over the protruding part 5b. As a result, the roller 4 is inserted deep into the track groove 5, and the internal parts are assembled. After the internal parts are assembled in this manner, the outer joint member 2 is elastically restored, and the interval W2 between the pair of raised portions 5b becomes smaller than the outer diameter D of the roller 4 again. The raised portion 5b restricts the movement of the roller 4 from the track groove 5 to the outside, thereby preventing the internal parts from coming off.

The pull-out preventing force of the protuberance 5b is set to be greater than the pull-out force that can occur when the joint is attached to the vehicle body or the like. Therefore, the internal parts will not come off from the outer joint member 2 due to the pull-out force generated during the assembly of the joint. However, when a pull-out force larger than the pull-out force that can be generated during joint assembly is applied to the internal parts, the region near the open end of the outer joint member 2 is elastically deformed in the same manner as described above, and the protuberance 5b is displaced inside. Allows missing parts. As a result, the outer joint member and the internal component can be separated after assembly, improving the workability of repair and maintenance.

A method for manufacturing the outer joint member according to the present embodiment will be described below.

First, the track grooves 5' before finishing are formed in the outer joint member 2 by forging (see FIG. 5). The side surface 51 ′ and the large-diameter cylindrical surface 52 of the unfinished track groove 5 ′ in the illustrated example are parallel to the axial direction and reach the open end surface 2 a of the outer joint member 2 .

Next, the outer joint member 2 is heat-treated. Specifically, for example, high-frequency heat treatment is performed on a pair of side surfaces 51 ′ of the unfinished track grooves 5 ′ of the outer joint member 2 that face each other. In this case, the heat treatment may be applied to the entire axial direction of the side surface 51' of the unfinished track groove 5', or the vicinity of the opening end of the side surface 51' of the unfinished track groove 5' (the area where the raised portion 5b is formed) may be heat-treated. A heat treatment may be applied to the axial region except for this. Alternatively, the entire outer joint member 2 may be carburized and quenched.

Thereafter, the side surfaces 51' of the unfinished track grooves 5' are finished by machining. In the present embodiment, machining is performed by cutting, particularly turning such as milling. By this machining, the roller guide surface 5a and the raised portion 5b are continuously formed by removing the dotted area in FIG. In the illustrated example, the side surface 51' of the unfinished track groove 5' is machined over the entire axial region. For this reason, a machined surface is formed on the entire roller guide surface 5a and the protuberance 5b, leaving traces of machining. As described above, the outer joint member 2 is formed with the track groove 5 having the roller guide surface 5a and the raised portion 5b. In the illustrated example, the amount of projection of the raised portion 5b, that is, the amount of removal by cutting is exaggerated, but it is actually about 0.1 to 1.0 mm. Therefore, the hardened layer due to the heat treatment remains on the roller guide surface 5a after cutting.

By forming the roller guide surfaces 5a of the track grooves 5 by machining as described above, the interval W1 (see FIG. 4) between the pair of roller guide surfaces 5a facing each other can be set with high accuracy. On the other hand, since the outer peripheral surface of the roller 4 is also finished by machining such as grinding, the outer diameter D of the roller 4 is also set with high accuracy. Thus, by setting both the gap W1 of the roller guide surface 5a and the outer diameter D of the roller 4 with high accuracy, the gap (W1-D) between the roller guide surface 5a and the roller 4 can be adjusted with high accuracy. Since it can be controlled, it is easy to form the appropriate gap to be provided (eg, 0.01 to 0.1 mm). Further, by finishing the roller guide surface 5a by machining, the surface roughness of the roller guide surface 5a can be reduced. As described above, the internal parts including the roller 4 move in the axial direction with respect to the outer joint member 2, and the vibration when the roller 4 transfers on the roller guide surface 5a can be suppressed.

Further, by forming the raised portions 5b of the track grooves 5 by machining, the interval W2 (see FIG. 4) between the pair of raised portions 5b facing each other can be set with high accuracy. On the other hand, as described above, since the outer diameter D of the roller 4 is also set with high accuracy, it is possible to set the amount of interference (D−W2) between the roller 4 and the raised portion 5b with high accuracy. It becomes easier to manage the retaining force of internal parts including. Thus, forming the protuberance 5b by machining results in a higher processing cost than forming by crimping, but by forming it at the same time as the above roller guide surface 5a by machining, the entire outer joint member 2 can be cost increase can be suppressed.

The invention is not limited to the above embodiments. Other embodiments of the present invention will be described below, but overlapping descriptions of the same points as those of the above-described embodiments will be omitted.

In the above-described embodiment, the case where the entire area of the raised portion 5b is formed by machining is shown, but the present invention is not limited to this, and a forged surface may be left on a part of the raised portion 5b. Specifically, as shown in FIG. 6, for example, the raised portion 5b is provided adjacent to the joint opening side of the inclined surface 5b1 displaced inward (toward the center of the track groove 5) toward the joint opening side. and an axial surface 5b2. Of the side surfaces 51' of the unfinished track grooves 5' parallel to the axial direction, machining is performed on the axial region excluding the vicinity of the opening end (axial surface 5b2) to remove the dotted region in FIG. An inclined surface 5b1 and a roller guide surface 5a are formed. In this case, the inclined surface 5b1 and the roller guide surface 5a are machined surfaces, and the axial surface 5b2 is a forged surface.

In the embodiment shown in FIGS. 7 and 8, a track groove chamfered portion 20 is provided between the opening end face 2a of the outer joint member 2 and the raised portion 5b. The track groove chamfered portion 20 is formed of an inclined surface that is inclined toward the center of the track groove 5 as it goes from the opening end face 2a toward the inner side of the joint (lower side in the drawing). In this embodiment, the straight track groove chamfered portion 20 is formed in the axial cross section shown in FIG. In addition, the track groove chamfered portion 20 may have a convex curved surface shape (for example, a convex circular arc shape in cross section). The inclination angle of the track groove chamfered portion 20 with respect to the axial direction is preferably 45 degrees or less. The track groove chamfered portion 20 may be provided at least in a region of the track groove 5 with which the roller 4 contacts. In the illustrated example, the track groove chamfered portion 20 is provided throughout the extending direction of the opening edge of the side surface 51 of the track groove 5 . That is, one end of the track groove chamfered portion 20 reaches the large diameter cylindrical surface 52, and the other end of the track groove chamfered portion 20 reaches the upper chamfered portion 2c of the small diameter cylindrical surface 2d. In addition, the track groove chamfered portion 20 may be provided in a portion of the opening edge of the side surface 51 of the track groove 5 in the extending direction (for example, an intermediate region excluding both ends in the extending direction).

The track groove chamfered portion 20 can be formed by forging, for example. Specifically, as shown in FIG. 9, when forming the unfinished track groove 5' by forging, the track groove chamfered portion 20 is formed at the upper end of the side surface 51' of the unfinished track groove 5'. After that, of the side surface 51' of the unfinished track groove 5', the area behind the track groove chamfered portion 20 of the joint is machined to remove the dot area in the drawing, thereby forming the roller guide surface 5a and the ridges. A portion 5b is formed. In this case, the roller guide surface 5a and the raised portion 5b are machined surfaces, and the track groove chamfered portion 20 is a forged surface.

Alternatively, the track groove chamfered portion 20 may be formed by machining. In this case, the pre-finishing track groove 5' is formed parallel to the axial direction up to the open end by forging (see FIG. 5), and then by machining, the roller guide surface 5a, the raised portion 5b, and the track groove chamfered portion are formed. form 20; In this case, the entire side surface 51 of the track groove 5 (roller guide surface 5a, raised portion 5b, and track groove chamfered portion 20) is machined.

By providing the track groove chamfered portion 20 at the open end of the side surface 51 of the track groove 5 in this way, when the roller 4 is pushed into the track groove 5 , the roller 4 is press-fitted while being in contact with the track groove chamfered portion 20 . Therefore, it is possible to prevent a large contact surface pressure from acting on the roller 4 . Thereby, it is possible to suppress the occurrence of contact marks on the surface of the roller 4 and the adhesion of a part of the outer joint member to the surface of the roller 4 . In addition, since the track groove chamfered portion 20 functions as a guide surface for guiding the roller 4, the roller 4 is less likely to be tilted, making it easier to assemble internal parts.

The present invention is not limited to being applied to a roller-type sliding constant velocity universal joint having rollers as rolling elements as shown in FIGS. It is also applicable to constant velocity universal joints.

As a ball-type sliding constant velocity universal joint, for example, a double offset constant velocity universal joint shown in FIGS. 10 and 11 is known. This double offset type constant velocity universal joint includes an outer joint member 102 having a plurality of track grooves 105 on its inner peripheral surface, an inner joint member 103 having a plurality of track grooves 106 on its outer peripheral surface, an outer joint member 102 and an inner joint A plurality of balls 104 as rolling elements arranged between the opposing track grooves 105 and 106 of the member 103 and balls interposed between the inner peripheral surface of the outer joint member 102 and the outer peripheral surface of the inner joint member 103. and a cage 107 that holds 104 . A ball guide surface 105a and a raised portion 105b are formed in the track groove 105 of the outer joint member 102 by machining. The details of the ball guide surface 105a and the raised portion 105b are the same as those of the roller guide surface 5a and the raised portion 5b in the above-described embodiment, so the description thereof will be omitted.

1 Tripod type constant velocity universal joint (sliding constant velocity universal joint)
2 outer joint member 3 tripod member (inner joint member)
4 roller 5 track groove 5' pre-finishing track groove 5a roller guide surface 5b raised portion 6 boss portion 7 leg shaft 8 shaft 14 roller unit 15 boot 20 track groove chamfered portion

Claims (11)

A constant velocity sliding type in which a plurality of track grooves for accommodating rolling elements are formed on the inner peripheral surface, and rotational torque is transmitted through the rolling elements to the inner joint member while allowing angular displacement and axial displacement. In the outer joint member for universal joint,
The track groove has a rolling element guide surface parallel to the axial direction and a raised portion provided on the joint opening side of the rolling element guide surface,
An outer joint member for a sliding constant velocity universal joint, wherein the rolling element guide surface and the raised portion are formed by machining. 2. The outer joint member for a sliding constant velocity universal joint according to claim 1, wherein a part of said raised portion is formed by machining and the remaining portion has a forged surface. 2. The outer joint member for a sliding constant velocity universal joint according to claim 1, wherein the entire raised portion is machined. 4. The sliding according to any one of claims 1 to 3, wherein the rolling element can be mounted on and removed from the track groove over the raised portion while elastically deforming a region in the vicinity of the opening end including the raised portion. Outer joint member for constant velocity universal joints. The outer joint member for a sliding constant velocity universal joint according to any one of claims 1 to 4, having a track groove chamfered portion between the open end face and the raised portion. The outer joint member for a sliding constant velocity universal joint according to claim 5, wherein the track groove chamfered portion is formed by machining. The outer joint member for a sliding constant velocity universal joint according to claim 5, wherein the track groove chamfered portion is formed by forging. The outer joint member according to any one of claims 1 to 7, the inner joint member having a plurality of track grooves formed on the outer peripheral surface, the track groove of the outer joint member and the track groove of the inner joint member. A sliding constant velocity universal joint comprising a plurality of rolling elements arranged on a track formed by A constant velocity sliding type in which a plurality of track grooves for accommodating rolling elements are formed on the inner peripheral surface, and rotational torque is transmitted through the rolling elements to the inner joint member while allowing angular displacement and axial displacement. In the method for manufacturing an outer joint member for a universal joint,
a step of forming pre-finishing track grooves by forging;
A sliding type having a step of forming a rolling element guide surface parallel to the axial direction and a raised portion provided on the joint opening side of the rolling element guide surface by machining the track groove before finishing. A method for manufacturing an outer joint member for a constant velocity universal joint. 10. The method of manufacturing an outer joint member for a sliding constant velocity universal joint according to claim 9, wherein the forging process forms a track groove chamfered portion between the opening end face and the raised portion. 10. The method of manufacturing an outer joint member for a sliding constant velocity universal joint according to claim 9, wherein a track groove chamfered portion is formed between the open end surface and the raised portion by the machining.

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