JPH04147726A - Manufacture of die for forming outer ring of synchronous joint - Google Patents

Abstract

PURPOSE:To improve the accuracy of manufacture of the die for forming the outer ring of synchronous joint by fit-inserting and attaching the inner cup spherical part forming segment to the lateral hole drilled on the die body for forming the truck groove of cup part. CONSTITUTION:At the time of manufacturing the outer ring W of the synchronous joint, the die body for forming the truck groove (c) of the outer ring W and the segment body 8 for forming the inner spherical surface part (h) to be the under-cut part are manufactured separatedly, each segment body 8 is inserted into the lateral hole 7 drilled to the die body and both are assembled. Therefore, with respect to the projecting line part 5 for forming the truck groove (c) of die body, the straight part (f) of truck groove part (c) and the curving part (g) can be finished respectively with two kinds of grinding stones having the groove part of same depth, so each projecting part can be formed uniformly and with high accuracy, by which the die for forming the outer ring can be manufactured on a larg scale and with uniform accuracy.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a method for manufacturing a mold for molding the outer ring of a constant velocity joint by ironing, and more specifically, to The present invention relates to a method of manufacturing a mold that is inserted into the cup portion to mold the inner surface of the cup portion.

(Prior Art) Conventionally, as an outer ring of a constant velocity joint, the one shown in FIG. 1, for example, is known.

This outer ring W consists of a bowl-shaped cup part a and a shaft part extending concentrically from the bottom of the cup part a.
A plurality of track grooves C for rolling balls (not shown) are formed at intervals in the circumferential direction on the inner peripheral surface.

In this case, each track groove C has a straight portion f extending parallel to the axis of the cup portion a to a constant depth from the intermediate portion between the open end d and the bottom surface e of the cup portion a to the open end d. and,
From the middle part to the bottom part e, it is approximately curved and has a constant depth D.
2, and a curved part g extending at 2, and D r > D t
It is said that At the intermediate part of the inner circumferential surface of the cup part a, an inner spherical surface part that becomes a sliding surface of a retainer (not shown) inserted into the cup part a is formed on the top surface of the mountain part between the adjacent track grooves C. The inner spherical surface portion is smoothly connected to the peak surface between each track groove C at the curved portion g of the track groove C, while forming an undercut portion at the straight portion f. ing. Therefore, the depth of the track groove C is formed to gradually become deeper from the curved part g to the straight part f in the intermediate part due to the inner spherical surface part.

On the other hand, as a method for manufacturing this type of outer ring W, an outer ring material having a shape roughly similar to the outer ring W is manufactured from a billet material through various forming processes such as upsetting molding and extrusion molding,
Next, the outer ring material is ironed to form an outer ring W.
A method of molding is generally known.

In this case, in the ironing process of the outer ring material, a preliminary cup part of the outer ring material corresponding to the cup part a of the outer ring W is inserted into a punch that is a mold for molding the inner surface of the cup part a, The outer surface of the preliminary cup portion is squeezed between a punch and an annular die fitted over the outer surface of the preliminary cup portion, thereby forming the final cup portion a from the preliminary cup portion.

In this ironing process, the punch for forming the inner surface of the cup portion a of the outer ring W is naturally provided with a plurality of protrusions for forming the track grooves C on the outer peripheral surface thereof, A spherical molding part for molding the inner spherical part is provided in the valley between the protrusions.

Such a punch is manufactured from a mold material through various cutting and grinding processes, and usually, in the final finishing process, the circumferential surface of each protruding strip is ground over its entire length with a grindstone. In this case, as described above, the depth of each track groove C of the outer ring W is constant in the straight part f and the curved part g, except for the intermediate part, but the depth in the intermediate part is constant. Since the depth gradually increases from the curved portion g to the straight portion f, the depth of each protruding portion of the punch also changes in the same way as the depth of each track groove C. For this reason, conventionally, as a grindstone for grinding the circumferential surface of each protruding strip, a grindstone having a groove having the same cross-sectional shape as the curved portion g of each track groove C is used, and the groove of the grindstone is attached to each protruding strip. The circumferential surface of each protruding strip was ground by moving the protruding strip in the longitudinal direction from one end to the other end while fitting the protruding strip. In such grinding, although the curved portion of the protruding portion corresponding to the curved portion g of the track groove C can be ground by the grindstone to the hem of the protruding portion, the curved portion of the protruding portion corresponding to the curved portion g of the track groove The straight part and the intermediate part of the protruding part corresponding to the straight part f are deeper than the curved part of the protruding part, and the depth changes gradually, so the hem part thereof is ground with the grindstone. Therefore, the bottom portions of the protruding stripes that cannot be ground with the grindstone have been ground by electrical discharge machining, tracing machining, etc., and then finished by hand.

However, in the final grinding of each protruding part of the punch, there are parts to be ground with a grindstone and parts to be ground by electrical discharge machining, copying, etc., on each part of the protruding part. It is difficult to finish the circumferential surface uniformly over its entire length, and when manufacturing punches in large quantities, it is difficult to make the forming surface of each punch uniform in precision.

(Problem to be Solved) The present invention solves such inconveniences, and when manufacturing a mold for molding the outer ring by ironing,
In particular, a method of manufacturing a mold that enables the peripheral surface of each convex portion for forming each track groove of the outer ring to be ground uniformly over its entire length, and that enables mass production of molds with uniform precision. The purpose is to provide

(Means for Solving the Problems) In order to achieve the above object, the method for manufacturing a mold for forming an outer ring of a constant velocity joint of the present invention has a plurality of track grooves formed at intervals in the circumferential direction on the inner circumferential surface. and each track groove extends at a constant depth from an intermediate portion between an open end and a bottom surface of the cup portion to the open end in parallel with the axis of the cup portion. and a curved part that is substantially curved from the middle part to the bottom part and extends at a depth smaller than the depth of the straight part, and further includes a straight part in the middle part of the inner circumferential surface of the cup part. In an outer ring of a constant velocity joint in which an inner spherical surface part that is an undercut part is formed between each track groove, the inner surface of the cup part is molded when the outer ring is formed by ironing. A method of manufacturing a mold to be fitted into a mold, the mold having an outer surface having substantially the same shape as the inner surface of the cup portion of the outer ring except for the inner spherical surface portion, and having a convex shape in which each of the track grooves is to be formed. A step of manufacturing a preliminary mold in which the stripes are formed on the outer circumferential surface with a grinding allowance left, and a step of manufacturing the preliminary mold from the outer surface toward the axis of the mold material at locations corresponding to the respective inner spherical surface portions of the preliminary mold. After drilling a horizontal hole, for each convex strip of the cough mold material, a groove is formed at a location corresponding to the straight section on the circumferential surface of the convex strip to have the same depth as the straight section. At the same time, a part of the circumferential surface of the convex strip corresponding to the curved part is ground by a second grindstone having a groove having the same depth as the curved part to form each track groove. A step of obtaining a mold body having the final convex strips to be molded on the outer circumferential surface, and a molding surface that can be fitted into each of the horizontal holes and that is used to mold each of the inner spherical surface portions on the outer side surface. a step of manufacturing a piece body having the above-mentioned mold body; and a step of manufacturing a piece body having the above-mentioned mold body, and a metal mold for molding the inner surface of the cup portion by fitting each piece body into each side hole of the mold body and molding the inner surface of the cup portion by combining each piece body and the mold body. It is characterized by consisting of a step of obtaining a mold.

(Function) According to this means, when grinding the circumferential surface of the convex strip of the preliminary mold, the horizontal hole is bored at a location corresponding to the inner spherical surface of the outer ring of the preliminary mold. Therefore, each convex strip has a portion where the depth gradually changes due to its inner spherical surface portion, and substantially has a constant depth portion of the straight portion of the track groove of the outer ring, and a portion of the outer ring that has a constant depth. It can be considered that there are only two types of locations: the curved portion of the track groove and a location having a constant depth. Therefore, by using the first grindstone to grind the portions of each convex strip corresponding to the straight portion, and using the second grindstone to grind the portions of each convex strip corresponding to the curved portion, each The mold body is obtained by grinding the circumferential surface of the protruding portion over its entire length using these grindstones. After such grinding, if the piece bodies manufactured in parallel with the grinding are inserted into each horizontal hole, the piece bodies and the mold body together form a mold having the same shape as the inner surface shape of the outer ring. is obtained.

(Example) An example of a method of manufacturing a mold for forming an outer ring of a constant velocity joint according to the present invention will be described with reference to FIG. 1 and FIGS. 2 to 7.

FIG. 2 is an explanatory cross-sectional view of an outer ring forming mold apparatus equipped with a mold to be manufactured by applying the present invention, and FIG.
FIG. 4 is a flowchart for explaining the manufacturing method, and FIGS. 5 and 6 are explanatory diagrams for explaining the main parts of the manufacturing method.

In FIGS. 2 and 3, the mold apparatus is for molding the outer ring W by ironing, and includes a punch 1, which is a mold to be manufactured through the present invention, and an annular die 2. It is equipped with

The main part of the punch l consists of a mold body 4 that stands up on a base 3, and when the outer ring W is molded, the cup a of the outer ring W is fitted concentrically into the tip of the mold body 4. be supported. In order to mold the inner surface of the cup portion a, the outer circumferential surface of the tip of the mold body 4 is formed in the same shape as the inner surface of the cup portion a, except for a portion corresponding to the inner spherical surface portion. , the protruding strips 5 for molding the respective track grooves C are integrally formed, while the portions between the protruding stripes 5 corresponding to the respective inner spherical surfaces are molded from the outer circumferential surface thereof. A horizontal hole 7 is bored through a shaft hole 6 extending through the shaft center of the main body 4.

Further, the punch 1 has a piece body 8 fitted into each side hole 7.

Each piece body 8 has a molding surface 9 for molding each inner spherical surface portion of the cup portion a on the outer surface portion protruding outward from the horizontal hole 7, and the outer surface shape of the tip of the punch l is The molding surface 9 and the outer circumferential surface of the tip of the mold body 4 together have the same shape as the inner surface of the cup portion a.

In this case, each piece body 8 has an inner surface portion attached to a tapered surface 11 of a sliding body 10 that is slidably inserted into the shaft hole 6 of the mold body 4.
When the sliding body lO is slid in the shaft hole 6 to a position away from each piece 8 by the cylinder 12 connected thereto, the molded surface 9 is in the horizontal hole 7. It is possible to freely slide inside the horizontal hole 7 to a position where it is buried in the hole 7.

In such a mold device, with the cup portion a of the outer ring W fitted into the tip of the punch 1, the annular die 2 is moved concentrically toward the punch 1 and fitted onto the cup portion a. As a result, the cup portion a is squeezed between the punch 1 and the annular die 2, so that the inner surface of the cup portion a conforms to the outer shape of the tip of the mold body 4 and the molding surface 9 of the piece body 8. It is molded in the same way. After such forming, the sliding body 10 is separated from each piece body 8, and the outer ring W is removed from the punch 1 in this state. At this time, each of the pieces 8 forming the inner spherical part which becomes the undercut part of the cup part a is in a state where it can be freely buried in each horizontal hole 7 as described above, so that the outer ring W can be pulled out. As the pieces are removed, each piece 8 is buried in the horizontal hole 7, so that the outer ring W can be removed from the tip of the punch 1 without any trouble.

Next, a method of manufacturing a punch 1 constituted by the die body 4 and the piece body 8 by applying the present invention will be described in accordance with FIGS. 4 to 6 with reference to FIG. 2.

4 and 5, when manufacturing the punch 1, first, a preliminary mold 13 (shown in the fifth figure) having substantially the same shape as the mold body 4 is manufactured from a mold material (not shown). .

In this case, specifically, as shown in FIG. 4, the general outline shape of the preliminary mold 13 is cut and formed from the mold material using a lathe or the like, and the shaft hole 6 is formed through the shaft center of the preliminary mold 13. Then, using a milling machine or the like, the protruding portion 5 is formed leaving a grinding allowance, and the horizontal hole 7 is bored, and then the preliminary mold 13 is hardened. After the quenching, the cylindrical body and the flat part of the tip of the preliminary mold 13 are attached to the mold body 4.
Grind it to the same shape.

In FIG. 5, the preliminary mold 1 manufactured in this way
3 is formed to have almost the same external shape as the mold body 4 to be manufactured, except for the protruding stripes 5 and the like, and a grinding allowance is left in each protruding strip 5.

Next, as shown in FIGS. 4 and 5, the circumferential surface of each protruding strip 5 of the preliminary mold 13 is ground into the final shape using general grindstones 14a and 14b. More specifically, as shown in FIG. Corresponding part 5a) and
Each track groove C has a portion 5b where the curved portion g is to be formed (hereinafter referred to as the curved portion corresponding portion 5b), and these have a depth Dl of the straight portion f and a depth D of the curved portion g, respectively.
The depths DI and Dz are the same as t. The depth of the intermediate portion between the straight portion corresponding portion 5a and the curved portion corresponding portion 5b of each convex strip portion 5 changes depending on the molding surface 9 of the piece body 8 on which the inner spherical surface portion is to be molded. Although it is a place,
When each piece 8 is removed from the side hole 7 of the mold body 4,
Substantially, each convex strip 5 can be considered to consist of only two locations: a straight portion corresponding portion 5a having a depth Dl and a curved portion corresponding portion 5b having a depth.

Therefore, when grinding each protruding part 5 of the preliminary mold 13, the part 5a of the protruding part 5 corresponding to the straight part is cut into the curved part g.
Grinding is performed using the general grindstone 14a to a depth of D+ including the intermediate part between
Grinding is carried out using the general grindstone 14b so that the following results are obtained.

In this case, specifically, as shown in FIGS. 5 and 6, the full-form grindstone 14a has the same cross-sectional shape and depth as the straight portion f of the track groove C, and a groove portion 15a is formed on the outer peripheral surface portion over the entire circumference. When grinding each protruding part 5 with the full-form grindstone 14a, as shown in FIG. ．． With the groove portion 15a fitted in the groove portion 15a, the full-form grindstone 14a is inserted in the longitudinal direction of the convex portion 5 from the end of the straight portion corresponding portion 5a to the intermediate portion between the curved portion corresponding portion 5b. By rolling, the portion 5a corresponding to the straight portion of each protruding portion 5 is ground including the intermediate portion between it and the curved portion g.

In addition, like the full-form grindstone 14a, the full-form grindstone 14b is also approximately disk-shaped, with a groove 15b having the same cross-sectional shape as the curved portion g of the track groove C and a depth D2 formed over the entire circumference on the outer peripheral surface. With the cough groove portion 15b fitted to the curved portion corresponding portion 5b of each convex portion 5, the full-form grindstone 14b is moved from the end of the curved portion corresponding portion 5b to the straight portion corresponding portion 5.
The portion 5b of each protruding portion 5 corresponding to the curved portion is ground by rolling it in the longitudinal direction of the protruding portion 5 over the intermediate portion between the protruding portion 5 and the protruding portion 5.

In this case, in this embodiment, only the depths D+ and Dz are different between the straight portion corresponding portion 5a and the curved portion corresponding portion 5b of each convex portion 5, so that the full-form grindstone 14b is The peripheral edge of the shaped whetstone 14a is shown in Fig. 5 - dotted chain line X.
It is obtained by cutting at the position.

That is, when cutting each of the protruding stripes 5 of the preliminary mold 13, first, the portions 5a corresponding to the straight portions of each of the protruding stripes 5 are cut using the overall shape grindstone 14a as described above, and then the overall shape is cut. The peripheral part of the whetstone 14a is cut to form a full-form whetstone 14.
b, and the portion 5b corresponding to the curved portion of each convex strip 5 is ground using this general grindstone 14b.

As described above, in this embodiment, each of the protrusions 5 is ground with basically one type of general grindstone 14a, so that each of the protrusions 5 can be ground uniformly and precisely into the final shape. I try to do that.

After such grinding, as shown in FIG. 4, the mold body 4 is obtained by grinding the inner wall of each horizontal hole of the preliminary mold 13 with a jig using an NC machine tool.

On the other hand, each of the pieces 8 is manufactured in parallel with the manufacturing of the mold body 4 as described below.

That is, as shown in FIG. 4, first, a material (not shown) is heat treated, and then surface grinding and cylindrical grinding are sequentially performed to shape the material into the approximate outer shape of the piece body 8.

Next, the side surface of the piece body 8 is formed by wire electrical discharge machining, while the tapered surface 11 on the inner side surface of the piece body 8 is formed by electric discharge machining, and after this, the piece body 8 is made flat by jig grinding. After forming the surface portion into the final shape, the forming surface 9 is jig-ground using an NC machine tool to form the forming surface 9 into the final shape, thereby obtaining each piece body 8.

After manufacturing the mold body 4 and each piece body 8 as described above, each piece body 8 is fitted into the horizontal hole 7 of the mold body 4 to assemble them, and in this assembled state, these pieces are assembled. Final surface finishing is performed by lapping or the like on the surface, thereby producing the bunch 1. In this case, the sliding body lO manufactured separately from these is also inserted into the shaft hole 6 of the mold body 4 and assembled.

In this way, in manufacturing such a bunch 1, in particular,
When grinding each of the protrusions 5 of the mold body 4 into the final shape in which the track grooves C of the outer ring W are to be formed, the inner spherical surface portions which will become the undercut portions of the outer ring W are to be formed. Piece body 8
Since each convex strip 5 is ground with the mold body 4 removed, the grinding is carried out using the general grindstones 14a, 14.
b, it is possible to grind the entire length and circumference of each convex strip 5 without any trouble, and in this way, the grinding wheels 14a, 14
By grinding each protruding part 5 into the final shape using only b, it is possible to form each protruding part 5 uniformly with high precision, and in turn, it is possible to mass-produce punches 1 with uniform precision. .

(Effects) As is clear from the above description, according to the method for manufacturing a mold for forming an outer ring of a constant velocity joint of the present invention, a mold body for forming a track groove etc. of a cup portion of an outer ring, A plurality of pieces for molding the inner spherical surface that will become the undercut part of the cup part are manufactured separately, each piece is inserted into a horizontal hole drilled in the mold body, and both pieces are assembled. By obtaining a mold for forming an outer ring, in particular, the convex strip of the mold body in which the track groove is to be formed can be formed into two grooves having the same depth as the straight portion and the curved portion of the track groove. Can be finished by grinding with different types of whetstones.
Each convex strip can be formed uniformly and accurately. In this way, by grinding and finishing each of the convex stripes of the mold body with a grindstone, the outer ring molding mold can be manufactured in large quantities with uniform precision.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view of an example of an outer ring of a constant velocity joint, FIG. 2 is an explanatory cross-sectional view of a mold device for forming an outer ring equipped with a mold to be manufactured using the present invention, and FIG. FIG. 2 is a sectional view taken along the line ■--■, FIG. 4 is a flowchart for explaining the manufacturing method, and FIGS. 5 and 6 are explanatory views for explaining the main parts of the manufacturing method. W... Outer ring C... Track groove e Bottom part g... Curved part 1... Outer ring molding mold 5... Convex strip part 8... Piece body 13... Preliminary mold a ...Cup part d...Opening end f...Straight part h...Inner spherical surface part (punch) 7...Horizontal hole 9...Molding surface 14a...First grindstone 14b... Second whetstone 15a. 15b...Groove

Claims (1)

[Claims] 1. It has a cup part in which a plurality of track grooves are formed at intervals in the circumferential direction on the inner peripheral surface, and each track groove is located in the intermediate part between the open end and the bottom part of the cup part. a straight part extending from the center to the opening end at a constant depth parallel to the axis of the cup part; and a straight part extending from the middle part to the bottom part at a depth smaller than the depth of the straight part while being substantially curved. In an outer ring of a constant velocity joint, an inner spherical surface part that is an undercut part with respect to the straight part is formed between each track groove at an intermediate part of the inner peripheral surface of the cup part, A method for manufacturing a mold that is inserted into the cup portion to shape the inner surface of the cup portion when the outer ring is formed by ironing, the method comprising: forming a mold that is inserted into the cup portion to form the inner surface of the cup portion, the inner surface shape of the cup portion of the outer ring excluding the inner spherical surface portion; a step of manufacturing a preliminary mold having an outer surface portion having substantially the same shape as that of the preliminary mold, and in which the protruding portions for forming each of the track grooves are formed on the outer circumferential surface with a grinding allowance left; Drilling a horizontal hole from the outer surface toward the axis of the mold material at a location corresponding to each inner spherical surface portion;
After the drilling, for each convex strip of the mold material, a portion of the circumferential surface of the convex strip corresponding to the straight section is ground using a first grindstone having a groove having the same depth as the straight section. At the same time, a final convex portion to form each track groove is formed by grinding a portion of the circumferential surface of the convex portion corresponding to the curved portion with a second grindstone having a groove portion having the same depth as the curved portion. a step of manufacturing a piece body that can be fitted into each of the horizontal holes and has a molding surface for molding each of the inner spherical surface portions on the outer surface portion; After the manufacturing, each piece is fitted into each side hole of the mold body, and each piece and the mold body are combined to obtain a mold for molding the inner surface of the cup portion. A manufacturing method for a mold for forming the outer ring of a constant velocity joint.