JPH0685964B2 - Manufacturing method of outer ring for ball joint - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION A. Object of the Invention (1) Field of Industrial Application The present invention has an outer ring for a ball joint, that is, a cup shape, and extends in the generatrix direction on a spherical inner peripheral surface having a center located inside. A method of manufacturing a device having a plurality of ball rolling grooves, each of which has a retainer sliding surface between adjacent ball rolling grooves, and more particularly, a core die and a plurality of radially arranged outer circumferences of the core die. The punch formed by the mold and the split type is covered with a cup-shaped material having the ball rolling groove and the retainer sliding surface roughly formed, and then the peripheral wall of the material is ironed by cooperation of the punch and the die. The present invention relates to an improvement in a method for finishing the ball rolling groove and the retainer sliding surface by working.

(2) Conventional Technology Conventionally, in this type of manufacturing method, a punch in which each molding die is configured to be slidable in the axial direction of the core die is used, and the central portion of the bottom surface of the material is brought into contact with the tip end surface of the core die. The ironing is carried out, and ironing is performed with a space left between the outer peripheral portion of the bottom surface and the tip surface of each molding die (see Japanese Patent Publication No. 59-44138).

(3) Problems to be Solved by the Invention In the ironing process, after the tip of the processed portion of the die passes through the diameter line passing through the center of the spherical inner peripheral surface and intersecting the core axis, the opening portion of the material is formed. Since the spherical inner peripheral surface is moved inward so as to be narrowed and follows the forming die, a pressing force acting from the front to the diagonal rear in the ironing process direction acts on each forming die, and A component force is generated in the mold in the direction opposite to the ironing direction. Therefore, if there is a space between the outer periphery of the bottom surface of the material and the tip surface of each molding die as in the conventional method, the mutual position of each molding die and the material circumferential wall is (the side that fills the space) by the component force. In addition, there is a possibility that it may move a little, so that there is a problem that even if each mold itself is manufactured with high accuracy, the finishing accuracy of each ball rolling groove and each retainer sliding surface deteriorates.

In the above-mentioned conventional ironing process, the tip end of the core and the center of the bottom surface of the material are always in contact with each other from the beginning of processing, and the contact point becomes the bending fulcrum of the ironing process. The position near the target center (that is, the position relatively far from the peripheral wall of the material to be ironed) tends to increase the amount of springback of the peripheral wall after the ironing, and the processing accuracy is also high. Cause to decrease.

The present invention has been proposed in view of the above circumstances, and an object thereof is to provide a method for manufacturing an outer race for a ball joint, which can solve the problems of the conventional ironing method using a split punch.

B. Structure of the Invention (1) Means for Solving the Problems In order to achieve the above-mentioned object, the present invention provides the bottom surface of the raw material and the core die during the ironing process from the start to the end. It is characterized in that a gap is provided between the surfaces facing the front end surface of the mold and the outer peripheral portion of the bottom surface of the same material is supported by the front end surface of each molding die.

(2) Action According to the above-mentioned method, the material is pressed against the front end surface of each molding die by the ironing load during the ironing process. The mutual position of the peripheral walls of the material does not move inadvertently. In addition, since the fulcrum of ironing exists on the tip surface of each mold, the distance between the fulcrum and the peripheral wall of the material to be ironed can be made relatively short, so that only the spring of the peripheral wall of the material after ironing The amount of backing is reduced.

In this case, since a gap is provided between the bottom surface of the material and the tip end surface of the core die, the core die and each forming die may be slightly different from each other in the relationship in the ironing process direction due to a manufacturing error of each part. Even if the variation occurs, the front end surface of each molding die can always be surely brought into contact with and supported by the outer peripheral portion of the bottom surface of the material without contacting the bottom surface of the core with the bottom surface of the material from the beginning of the ironing process.

(3) Embodiments FIGS. 1 and 2 show an outer ring 1 for a ball joint, the outer ring 1 being a cup-shaped main body 2 and a mounting shaft 3 protrudingly provided on the outer surface of the bottom wall thereof.
Composed of and.

In the main body 2, a spherical inner peripheral surface 6 located between the opening 4 and the vicinity a of the bottom surface 5 and having the center O positioned inside the main body 2, and between the vicinity a and the bottom surface 5. Thus, a convex arc-shaped inner peripheral surface 7 that bulges inward is formed. On both inner peripheral surfaces 6 and 7, there are provided a plurality of, in the illustrated example, six ball rolling grooves 8 formed at equal intervals on the circumference and extending in the generatrix direction. It functions as the retainer sliding surface 9.

Each ball rolling groove 8 in the inner peripheral surface generatrix direction of the main body 2
Is formed such that the opening 4 side of the diameter line BB passing through the center O and intersecting the axis AA of the mounting shaft 3 linearly moves outward toward the end face of the opening 4, and The spherical inner peripheral surface 6 extends from the diameter line BB to the vicinity b of the bottom surface 5.
Is formed in an arc shape with the center O of the center as the center, and is further formed so as to linearly move inward toward the bottom surface 5 from the neighboring portion b to the bottom surface 5.

The outer peripheral surface of the outer ring 1 is provided with a recess 10 corresponding to each retainer sliding surface 9 and extending in the generatrix direction. The recess 10 is formed by a die described later so as to increase the ironing rate of the peripheral wall portion corresponding to the retainer sliding surface 9.

FIGS. 3 and 4 show a material 11 used to obtain the outer ring 1 by ironing. The material 11 is formed by rearwardly forming each ball rolling groove 8 and each retainer sliding surface 9 roughly. There is. In the illustrated example, the material 11 has a shallow depth and the peripheral wall has a large thickness, and the diameter line BB is located in the vicinity of the opening 12, and the bottom surface is smaller than the diameter line BB.
On the 13 side, each ball rolling groove 8 and each retainer sliding surface 9 have substantially the same shape as the finished product, and the diameter line BB
On the opening 12 side, the ball rolling grooves 8 and the retainer sliding surfaces 9 are formed so as to linearly move outward toward the end surface of the opening 12.

Further, the outer peripheral surface is formed so as to spread outward from the intermediate portion located on the bottom side with respect to the diameter line BB toward the end surface of the opening 12, so that the ironing ratio of the peripheral wall of the material 11 is increased from the bottom side to the opening. It is designed to increase toward 12 end faces.

Each retainer sliding surface 9 is formed with a clearance groove 14 extending in the generatrix direction from the end surface of the opening 12 toward the bottom surface 13. Each escape groove 14
Has an arcuate shape in a cross section orthogonal to the generatrix direction and tapers from the end surface of the opening 12 toward the bottom surface 13, and the depth is substantially constant over the entire length.

The relief groove 14 is provided to prevent a part of the retainer sliding surface 9 from being pushed inward during the ironing process and biting into a gap between adjacent molding dies described later.

In FIGS. 5 and 5A, the ironing punch 15 and the die 16 are configured as follows.

The punch 15 is divided into a core 17 and a plurality of, for example, six molding dies 18 radially arranged on the outer periphery of the core 17 so that the outer ring 1 after ironing can be released. Composed into an expression

The core 17 has a stepped base end portion 20 having a circular cross section on the base 19 side.
And a columnar portion 22 having a regular hexagonal cross-section that is continuously provided on the small-diameter portion 21 of the base end portion 20 thereof, and a plate-shaped portion 23 projecting from each ridge of the columnar portion 22. A guide groove 24 for a molding die is defined by the shape portion 23. The columnar portion 22 is formed so as to taper from the base end portion 20 side to the upper end surface 25 as a tip end surface, and the columnar portion 22 has a main hole 26 extending in the axial direction thereof.
And a grease passage 28 is formed, which is branched from the main hole 26 and has a branch hole 27 that opens to the bottom surface of each guide groove 24.

Each molding die 18 is fitted in each guide groove 24 so as to be slidable in the vertical direction in FIG. 5, and the lower end surface of each molding die 18 is fitted to the small-diameter portion 21 of the core die 17. The upper end surface 30 serving as the tip end surface of each molding die 18 projects from the upper end surface 25 of the columnar portion 22 in a state of being in contact with the upper surface of the annular support table 29.

A projecting surface 31 for finish-molding the ball rolling groove 8 is formed on the outer peripheral surface of the upper part of each molding die 18, and adjacent projecting surfaces 31 are formed.
Both hem portions form a protruding surface 32 that finish-molds the retainer sliding surface 9.

Engagement holes 33 that open laterally are formed in the vicinity of the lower end of each molding die 18, and in each engagement hole 33, each projectingly provided on the inner peripheral surface of an annular lifting plate 34 that surrounds all the molding dies 18. The protrusion 35 engages. The tip of a piston rod 37 of a plurality of hydraulic or pneumatic cylinders 36 arranged below the lift plate 34 is screwed onto the lift plate 34.

When the piston rod 37 of the cylinder 36 contracts and the lower end surface of each molding die 18 comes into contact with the upper surface of the support base 29, each molding die 18 is in the ironing position, and the piston rod 37 extends to form the piston 38. When contacting the ceiling surface of the cylinder body 39, the projecting surfaces 31 and 32 of each molding die 18 are above the upper end surface 25 of the columnar portion 22, and each molding die 18 occupies the releasing position.

The die 16 has an annular shape, and its inner peripheral surface is formed so that its inner diameter is smaller than the minimum outer diameter of the material 11 so as to function as the processing portion 40 from the upper opening to the middle portion, and from the middle portion to the lower opening. In order to function as the guide portion 41 for the material 11, the diameter is increased toward the lower opening.

Next, punch 15 and die using the material 11 shown in FIGS. 3 and 4
The ironing process by 16 will be described.

First, as shown in FIG. 5, each forming die 18 is held at the ironing position, and the material 11 is put on the upper portion of each forming die 18 and the bottom surface thereof is formed.
13 The outer peripheral portion is supported by the upper end surface 30 of each molding die 18, and the roughly formed ball rolling grooves 8 and retainer sliding surfaces 9 are fitted to the protruding surfaces 31 and 32. In this case, the upper end surface 25 of the columnar portion 22
A gap g ₁ is formed between the center of the bottom surface 13 and the central portion of the bottom surface 13 of the material 11 that faces the material, and the material 11 is held in an unsupported state with respect to the columnar portion 22.

As shown in FIG. 6, the die 16 is lowered to guide the guide.
The processed portion 40 is bited into the peripheral wall of the material 11 by the guide action of 41, and while extending the peripheral wall, each ball rolling groove 8 and each retainer sliding surface 9 are plastically deformed so as to follow the protruding surfaces 31 and 32, respectively. To get the outer ring 1.

In this ironing process, each retainer sliding surface 9 is moved inward so that the opening 12 of the material 11 is narrowed after the lower end of the processed portion 40 of the die 16 passes through the diameter line BB, and the forming die is formed. In order to follow the protruding surface 32 of the 18, a pressing force F is applied to each of the forming dies 18 from the front to the diagonal rear of the ironing direction, and due to the pressing force F, the forming dies 18 are moved in the direction opposite to the ironing direction. A component force f is generated, but in this embodiment, since the outer peripheral portion of the bottom surface 13 of the material 11 is pressed against the upper end surface 30 of each forming die 18 by the ironing load, each forming die 18 is caused by the component force f. It never moves. Further, since the fulcrum of ironing exists on the upper end surface 30 of each molding die 18, and the distance between the fulcrum and the peripheral wall to be ironed is short, the amount of springback of the peripheral wall after ironing is small.

At the time of such ironing, a gap g ₁ is provided between the bottom surface 13 of the material 11 and the tip surface 25 of the core 17, so that the core 17 and each of the moldings may be formed due to manufacturing errors of each part. Even if there is some variation in the relative position of the die 18 in the ironing direction, from the beginning of the ironing process, the tip surface 25 of the core die 17 should not be applied to the bottom surface 13 of the material 11 Tip surface
The 30 can always be reliably brought into contact with and supported by the outer peripheral portion of the bottom surface 13 of the material 11.

As a result, the finishing accuracy of each ball rolling groove 8 and each retainer sliding surface 9 becomes good.

During the ironing process, as shown in FIG. 6A, the retainer sliding surface 9 follows the projecting surface 32 around both sides of the clearance groove 14 in each retainer sliding surface 9, so that the compressive force in the circumferential direction opposite to each other can be obtained. f ₁ is received, and the bottom side receives the pushing force f ₂ toward the molding die 18. In this case, since the escape groove 14 has a circular arc shape that is difficult to buckle, the periphery of the escape groove 14 is extruded inward by plastic deformation by the compression force f ₁ and the pushing force f ₂ . As described above, since the ironing rate of the peripheral wall of the material 11 increases from the bottom side toward the end face of the opening 12, the extrusion amount around the escape groove 14 increases in the same direction, but the escape groove Since 14 spreads from the bottom surface 13 side of the material 11 toward the end surface of the opening 12 and its cross-sectional area gradually increases,
The escape groove 14 is filled according to the amount of extrusion.

As a result, each retainer sliding surface 9 becomes substantially smooth, and a part of the retainer sliding surface 9 does not bite into the gap g ₂ between the adjacent molding dies 18. When each retainer sliding surface 9 is formed to be substantially smooth as described above, the race processing for the retainer sliding surface 9 can be omitted.

As shown in FIG. 7, the cylinder 36 is actuated, and each molding die 18
To hold them in the release position. Each mold 18
Since the columnar portion 22 moves in a direction in which the columnar portion 22 is tapered, the distance between the two molding dies 18 facing each other is narrowed, and each ball rolling groove 8
A gap g ₃ is formed between the end of the retainer sliding surface 9 on the opening 4 side and the protruding surface 32, and a gap g ₄ is formed between the end of the retainer sliding surface 9 on the opening 4 side and the protruding surface 32. .

As shown in FIG. 8, the outer ring 1 is raised and the gaps g ₃ and g ₄
The outer ring 1 is removed from each mold 18 using.

FIG. 9 shows another embodiment of the present invention. When the upper end surface 25 of the columnar portion 22 of the punch 15 and the upper end surface 30 of each forming die 18 are aligned with each other, the central portion of the bottom surface 13 of the material 11 ₁ and the columnar portion Upper surface 2 of part 22
The central portion of the bottom surface 13 of the material 11 ₁ is formed in a concave shape so as to form a gap g ₅ between the material 11 ₁ and the material g, and the material 11 ₁ is supported by the upper end surface 30 of each molding die 18.

FIG. 10, also the opening portion 4 side of the ball rolling grooves 8 shows the outer ring 1 ₁ formed in an arc shape around the center O of the spherical inner peripheral surface 6, the present invention provides such an outer ring 1 ₁ It also applies when manufacturing.

C. Effect of the Invention According to the present invention, the component force in the direction opposite to the machining direction acts on each mold during the ironing process as described above, but during the ironing process, the material is subjected to the ironing load and the tip surface of each mold is Therefore, even if each mold is configured to be slidable, the mutual position between each mold and the peripheral wall of the material does not deviately shift due to the component force. Moreover, since the fulcrum of ironing exists on the tip surface of each mold, and the distance between the fulcrum and the peripheral wall of the material to be ironed can be made relatively short, so the amount of springback on the peripheral wall of the material after ironing is reduced. can do. As a result, it is possible to greatly contribute to the improvement of finishing accuracy of each ball rolling groove and each retainer sliding surface.

Further, especially in the above ironing process, since a gap is provided between the bottom surface of the material and the tip face of the core die, the relationship between the ironing direction of the core die and each forming die due to manufacturing error of each part, etc. Even if there is some variation in position,
From the beginning of the ironing process, the tip end surface of each mold can be always brought into contact with and supported by the outer periphery of the bottom surface of the material without touching the tip end surface of the die to the bottom surface of the material. To be achieved.

[Brief description of drawings]

1st and 2nd show an outer ring, FIG. 1 is a perspective view, FIG. 2 is 1st
Fig. II-II sectional view, Figs. 3 and 4 show outer ring material, Fig. 3 is a perspective view, Fig. 4 is a sectional view taken along line IV-IV of Fig. 3, and Figs. Fig. 5 shows an ironing process of one embodiment of the invention, Fig. 5 is a longitudinal sectional view before working, and Fig. 5A is Fig. 5 Va-Va.
A line sectional view, FIG. 6 is a longitudinal sectional view of a main part immediately after processing, and FIG. 6A shows an extruding action around the clearance groove. FIG. 5A is an enlarged transverse sectional view of an essential part cut in the same direction as FIG. 5A, FIG. 7 is a longitudinal sectional view of an essential part before releasing, FIG. 8 is a longitudinal sectional view of an essential part during releasing, and FIG. 9 is the present invention. 10 is a longitudinal sectional view of a main part before ironing according to another embodiment of the present invention.
The drawing is a sectional view similar to FIG. 2 showing a modified example of the outer ring. O …… Center, 1,1 ₁ …… Outer ring, 6 …… Spherical inner peripheral surface, 8 …… Ball rolling groove, 9 …… Retainer sliding surface, 11,11 ₁ …… Material, 15 …… Punch, 16 dies, 17 dies, 18 dies, 25 dies, 25 dies
… Upper end surface as tip surface, 30 …… Upper end surface as tip surface

Claims (1)

[Claims] 1. A ball-shaped groove (8) which is cup-shaped and has a plurality of ball rolling grooves (8) extending in the generatrix direction on a spherical inner peripheral surface (6) whose center is located inside, and which are adjacent to each other. 8) In order to manufacture the ball joint outer ring (1, ₁₁ ) with the retainer sliding surface (9) between them, the core (17) and the outer periphery of the core (17) are radially arranged. A cup-shaped material (11, 11) in which the ball rolling groove (8) and the retainer sliding surface (9) are roughly formed in a punch (15) configured in a more split manner with a plurality of molding dies (18) ₁ ) and then the punch (1) on the peripheral wall of the material (11,11 ₁ ).
The ball rolling groove (8) and the retainer sliding surface (9) are ironed by the cooperation of 5) and the die (16).
In the manufacturing method of finish forming, the ironing process is performed from the start to the end of the ironing process. The bottom face (13) of the material (11, 11 ₁ ) and the tip face (25) of the core die (17). ) And a gap (g ₁ , g ₅ ) is provided between the surfaces facing each other, and the outer periphery of the bottom surface (13) of the same material (11, 11 ₁ ) is supported on the tip surface (30) of each of the molding dies (18). A method for manufacturing an outer ring for a ball joint, which is characterized in that