JPH0356135B2 - - Google Patents

Description

[Detailed Description of the Invention] A. Purpose of the Invention (1) Industrial Field of Application The present invention is an outer ring for a ball joint, that is, has a cup shape, has a spherical inner peripheral surface with the center located inside, and extends in the generatrix direction. A method for manufacturing a device having a plurality of ball rolling grooves, each of which has a retainer sliding surface between the adjacent ball rolling grooves, in particular having a cup shape,
obtaining a material in which the ball rolling grooves and the retainer sliding surface are roughly formed, and each retainer sliding surface is provided with an relief groove extending in the generatrix direction from the opening end surface toward the bottom surface; a core mold and the core; a step of covering the material over a punch configured in a split manner with a plurality of molds arranged radially around the outer periphery of the mold; ironing the peripheral wall of the material by the cooperation of the punch and the die; The present invention relates to an improvement in a method using: a step of finish forming the ball rolling groove and the retainer sliding surface;

(2) Prior Art The relief groove has a function of preventing a portion of the retainer sliding surface from being pushed out toward the punch and digging into the gap between adjacent molds during ironing. , is essential when using a split type punch as described above.

Conventionally, the relief groove has a U-shape in a cross section perpendicular to the generatrix direction thereof, and is formed so that the width and depth are equal from the end surface of the opening of the material toward the bottom surface.

(3) Problems to be Solved by the Invention However, in the relief groove having the above-mentioned shape, the bottom part tends to buckle and be pushed out in a convex shape toward the punch side during ironing. In addition, since the opening of the material is narrowed by ironing, the ironing rate of the peripheral wall of the material increases from the bottom side toward the opening end surface, so the amount of extrusion around the clearance groove is in the same direction. However, if the width and depth of the clearance groove are equal as described above, it is not possible to fill the groove according to the amount of extrusion around the clearance groove and smooth the retainer sliding surface.

As a result, traces of relief grooves are left on each retainer sliding surface, so lace processing must be applied to each retainer sliding surface after ironing, which increases manufacturing man-hours and costs. Since the material has to be manufactured taking into account the lace processing cost, there is a problem that the yield of the material is poor.

An object of the present invention is to provide the manufacturing method capable of solving the above problems.

B. Structure of the Invention (1) Means for Solving the Problems The present invention provides that the relief groove has an arc shape in a cross section perpendicular to the generatrix direction thereof, and extends from the end face of the material opening toward the bottom face. A feature is that the material is tapered.

(2) Effect The relief groove widens from the bottom side of the material toward the end face of the opening, and its cross-sectional area gradually increases, so the amount of extrusion around the relief groove increases in the same direction due to ironing. The escape groove will be filled accordingly.

This makes each retainer sliding surface substantially smooth, so that each retainer sliding surface can be completed by directly grinding each retainer sliding surface without lace processing.

(3) Embodiment Figures 1 and 2 show an outer ring 1 for a ball joint, and the outer ring 1 is composed of a cup-shaped main body 2 and a mounting shaft 3 projecting from the outer surface of its bottom wall.

The main body 2 has a spherical inner circumferential surface 6 which is located between the opening 4 and a vicinity a of the bottom surface 5 and whose center O is located inside the main body 2, and a spherical inner circumferential surface 6 which is located between the vicinity a and the bottom surface 5. A convex arc-shaped inner circumferential surface 7 that bulges inward is formed.
Both inner circumferential surfaces 6 and 7 are provided with a plurality of ball rolling grooves 8, six in the illustrated example, which are formed at equal intervals on the circumference and extend in the generatrix direction, and the spaces between adjacent ball rolling grooves 8 are It functions as a retainer sliding surface 9.

In the generatrix direction of the inner circumferential surface of the main body 2, each ball rolling groove 8 passes through the center O and extends along the axis A- of the mounting shaft 3.
The opening 4 side is formed so as to move outward in a straight line toward the end surface of the opening 4 from the diameter line B-B intersecting A, and from the diameter line B-B to the vicinity part b of the bottom surface 5. is formed in an arc shape centered on the center O of the spherical inner circumferential surface 6, and is further formed so as to move inward in a straight line toward the bottom surface 5 from the vicinity portion b to the bottom surface 5.

A recess 10 extending in the generatrix direction is provided on the outer circumferential surface of the outer ring 1 in correspondence with each retainer sliding surface 9 .
This recess 10 is formed by a die to be described later in order to increase the ironing rate of the peripheral wall portion corresponding to the retainer sliding surface 9.

3 and 4 show a raw material 11 used to obtain the outer ring 1 by ironing, and the raw material 11 is roughened by roughening each ball rolling groove 8 and each retainer sliding surface 9 by rear-extrusion processing. There is. In the illustrated example, the depth of the material 11 is shallow and the thickness of the peripheral wall is thick, and the diameter line B-B is located near the opening 12 and is closer to the bottom surface 13 than the diameter line B-B. , each ball rolling groove 8 and each retainer sliding surface 9 have substantially the same shape as the finished product, and on the opening 12 side of the diameter line B-B, each ball rolling groove 8 and each retainer sliding surface 9 have substantially the same shape as the finished product. Sliding surface 9
is formed so as to move linearly outward toward the end surface of the opening 12.

Further, the outer circumferential surface is formed so as to expand outward from the intermediate portion located on the bottom side of the diameter line B-B toward the end surface of the opening 12, so that the straining rate of the circumferential wall of the material 11 is increased from the bottom side to the opening side. 12 and increases toward the end face.

A relief groove 14 is formed in each retainer sliding surface 9 and extends in the generatrix direction from the end surface of the opening 12 toward the bottom surface 13. Each escape groove 14 has an arc shape in a cross section perpendicular to the generatrix direction, tapers from the end surface of the opening 12 toward the bottom surface 13, and has a substantially constant depth over its entire length.

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

The punch 15 is divided into a core 17 and a plurality of molds 18 (six in the illustrated example) arranged radially around the outer circumference of the core 17 so that the outer ring 1 after ironing can be released from the mold. Composed of formulas.

The core mold 17 has a stepped base end 20 with a circular cross section that exists on the base 19 side, and a small diameter portion 2 of the base end 20.
1, a columnar part 22 having a regular hexagonal cross section;
The columnar portion 22 includes plate-like portions 23 protruding from each ridgeline, and a mold guide groove 24 is defined by both adjacent plate-like portions 23 . The columnar portion 22 is formed to be tapered from the base end 20 side to the distal end surface 25, and the columnar portion 22 has a main hole 26 extending in the axial direction, and a main hole 26 branching from the main hole 26. A grease passage 28 consisting of a branch hole 27 opening at the bottom of each guide groove 24 is formed.

Each mold 18 is fitted into each guide groove 24 so as to be able to slide in the vertical direction in FIG.
The upper end surface 30 of each mold 18 is adapted to protrude from the upper end surface 25 of the columnar section 22 in a state in which it is in contact with the upper surface of the annular support base 29 fitted therein.

A protruding surface 31 for finishing forming the ball rolling groove 8 is formed on the upper outer peripheral surface of each mold 18, and a protruding surface 31 for finishing forming the retainer sliding surface 9 is formed by both skirts of the adjacent protruding surfaces 31. A surface 32 is formed.

An engagement hole 33 that opens laterally is formed near the lower end of each mold 18 , and each engagement hole 33 has a plurality of holes protruding from the inner circumferential surface of an annular lifting plate 34 surrounding all the molds 18 . The protrusion 35 is engaged. The tips of piston rods 37 of a plurality of hydraulic or pneumatic cylinders 36 disposed below the elevating plate 34 are screwed.

When the piston rod 37 of the cylinder 36 contracts and the lower end surface of each mold 18 comes into contact with the upper surface of the support base 29, each mold 18 is in the ironing position,
Also, the piston rod 37 extends and the piston 38
When the molds 18 come into contact with the ceiling surface of the cylinder body 39, the protruding surfaces 31 and 32 of each mold 18 are located above the upper end surface 25 of the columnar part 22, and each mold 18 occupies a mold release position.

The die 16 has an annular shape, and its inner diameter is smaller than the minimum outer diameter of the material 11 from the upper opening to the middle part in order to function as the processing part 40, and from the middle part to the lower opening the die 16 has an annular shape. In order to function as a guide part 41 for the material 11,
It is formed to expand in diameter toward the lower opening.

Next, use the punch 1 using the material 11 shown in Figures 3 and 4.
5 and the ironing process using the die 16 will be explained.

First, as shown in FIG.
The roughly formed ball rolling grooves 8 and the retainer sliding surfaces 9 are fitted into the protruding surfaces 31 and 32, respectively. In this case, the upper end surface 25 of the columnar part 22 and the bottom surface 13 of the material 11 facing thereto.
A gap g ₁ is formed between the columnar part 22 and the central part.
The blank 11 is held in an unsupported state.

As shown in FIG. 6, the die 16 is lowered and the processing part 40 is bitten into the peripheral wall of the material 11 by the guiding action of the guide part 41, and while stretching the peripheral wall, each ball rolling groove 8 and each retainer slide. Face 9
are plastically deformed so as to follow the protruding surfaces 31 and 32, respectively, to obtain the outer ring 1.

In this ironing process, after the lower end of the processed part 40 of the die 16 passes through the diameter line B-B, each retainer sliding surface 9 is moved inward so that the opening 12 of the material 11 is narrowed, and the molding die In order to imitate the protruding surface 32 of 18, a pressing force F acting diagonally backward from the front in the ironing direction acts on each mold 18, and due to the pressing force F, each mold 18 has a force F in the opposite direction to the ironing direction. A component force f is generated, but in this embodiment, the bottom surface 1 of the material 11 is
Since the outer periphery of each mold 18 is pressed against the upper end surface 30 of each mold 18, each mold 18 does not move due to the component force f. Further, since the fulcrum of the ironing process is located on the upper end surface of each mold 30, and the distance between the fulcrum and the peripheral wall to be ironed is short, the amount of spring back of the peripheral wall after the ironing process is reduced.

This improves the finishing accuracy of each ball rolling groove 8 and each retainer sliding surface 9.

During the ironing process, as shown in FIG. 6A, the retainer sliding surfaces 9 follow the protruding surfaces 32 around both sides of the escape groove 14 on each retainer sliding surface 9, so that opposing compressive forces in the circumferential direction are applied. The extrusion force f ₁ is received by the bottom side, and the extrusion force f ₂ is directed toward the mold 18.
receive. In this case, since the relief groove 14 has an arcuate shape that is difficult to buckle, the periphery of the relief groove 14 is pushed inward by plastic deformation due to the compressive force f ₁ and extrusion force f ₂ . As mentioned 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 amount of extrusion around the relief groove 14 increases in the same direction, but the relief groove 14 widens 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, so that the relief groove 14 is filled in accordance with the amount of extrusion.

As a result, each retainer sliding surface 9 becomes substantially smooth, and a portion of the retainer sliding surface 9 does not dig into the gap _g2 between adjacent molds 18. When each retainer sliding surface 9 is formed substantially smooth in this manner, lace processing on the retainer sliding surface 9 can be omitted.

As shown in FIG. 7, actuate the cylinder 36;
Each mold 18 is raised to hold them in the release position. Since each mold 18 moves in the direction in which the columnar portion 22 becomes tapered, both molds 18 facing each other
A gap g 3 is formed between the opening 4 side end of each ball rolling groove 8 and the protruding surface 31, and a gap g ₃ is created between the opening 4 side end of each retainer sliding surface 9 and the protruding surface. 32
A gap _g4 is formed between the two.

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

FIG. 9 shows another embodiment of the present invention, in which the punch 1
The upper end surface 25 of the columnar part 22 in 5 and each mold 1
When matching the upper end surface 30 of 8, material 11 ₁
The bottom surface ₁₃ of the material ₁₁
The center portion is formed in a concave shape, so that the material 11 ₁ is supported by the upper end surface 30 of each mold 18 .

FIG. 10 shows an outer ring 1 ₁ formed on the opening ₄ side of each ball rolling groove 8 in an arc shape centered on the center O of the spherical inner circumferential surface 6.
It also applies when manufacturing.

C. Effects of the Invention According to the present invention, since the shape of the relief groove is specified as described above, each relief groove can be filled during the ironing process, thereby making each retainer sliding surface substantially smooth. It is possible to eliminate the lace processing for the material, reduce manufacturing man-hours and costs, and improve material yield.

[Brief explanation of drawings]

Figures 1 and 2 show the outer ring, Figure 1 is a perspective view,
Figure 2 is a sectional view taken along the line taken from Figure 1, Figures 3 and 4 show the outer ring material, Figure 3 is a perspective view, Figure 4 is a sectional view taken taken from Figure 3, and Figures 5 to 8. 5 shows the ironing process of an embodiment of the present invention, FIG. 5 is a longitudinal sectional view before processing, FIG. 5A is a sectional view taken along line a-a in FIG. 5, and FIG. 6 is a longitudinal sectional view of the main part immediately after processing. Figure, 6th
Figure A is an enlarged cross-sectional view of the main part taken in the same direction as Figure 5A, showing the extrusion action around the relief groove, Figure 7 is a longitudinal cross-sectional view of the main part before mold release, and Figure 8 is during mold release. FIG. 9 is a vertical sectional view of the main part before ironing in another embodiment of the present invention, and FIG. 10 is a sectional view similar to FIG. 2 showing a modification 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, 12...opening ,1
3...Bottom surface, 14...Escape groove, 15...Punch,
16... Dice, 17... Core mold, 18... Molding mold.

Claims (1)

[Claims] 1. A cup-shaped spherical inner peripheral surface with the center located inside is provided with a plurality of ball rolling grooves extending in the generatrix direction, and a retainer is provided between the adjacent ball rolling grooves. In order to manufacture an outer ring for a ball joint with a sliding surface, it is cup-shaped, and the ball rolling groove and the retainer sliding surface are formed roughly, and each retainer sliding surface has an opening extending from the end surface toward the bottom surface. A step of obtaining a material having relief grooves extending in the generatrix direction; A step of covering the material over a punch configured in a split manner by a core and a plurality of molds arranged radially around the outer periphery of the core. and a step of final forming the ball rolling groove and the retainer sliding surface by ironing the peripheral wall of the material by the cooperation of the punch and die, wherein the relief groove is formed on its generatrix. A method of manufacturing an outer ring for a ball joint, characterized in that the material is formed into an arcuate shape in a cross section perpendicular to the direction and tapered from the end surface of the material opening toward the bottom surface.