JPH07155893A - Cold forming method and forming die for tooth shaped ring article - Google Patents

Abstract

PURPOSE:To shorten working time, to improve yields of materials and to reduce working cost by making it possible to obtain an accurate tooth-shaped ring article by plastic working. CONSTITUTION:In the case of plastic working of a ring article WO that is provided with a tooth-shaped part T on its outside cylindrical surface, the following die 1 and round shaft punch 2 are used. The die 1 is provided with tooth forming projections 4 corresponding to the dent shape of the tooth-shaped part T of the ring article WO and with tooth tip shaping projections 5 which are positioned between the tooth forming projections 4 on the inside cylindrical surface. A ring shaped base material W is successively pushed into this die 1, and extrusion is performed while a few pieces of in-process base material W are left inside the die 1. Incidentally, in the case of working a ring article that is provided with a tooth part on the inside cylindrical surface, the tooth forming projections 4 and the tooth tip shaping projections 5 are provided on the outer circumference of a lower punch, and the base material is pressed by an upper punch.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an external gear, an internal gear, a pulsar ring for detecting rotation, a ring-shaped article having a tooth profile such as a ring-shaped spline, and a molding die.

[0002]

2. Description of the Related Art Conventionally, a ring-shaped product of this type has a tooth profile formed by cutting. However, the cutting process requires a long processing time and the material yield is low, resulting in high processing cost. Therefore, plastic working is desired.

Therefore, it has been considered to form a tooth profile by the ironing process shown in FIG. That is, this is a method of processing the tooth profile portion T on the outer diameter surface of the material W by the tooth profile forming surface 53 of the die 51 by pushing the material W that has been previously drawn into a cup shape into the die 51 with the punch 52. When making a ring-shaped product, the end plate portion Wd of the material W is cut off.

According to the processing method of this proposed example, the productivity is better than that of the cutting processing, but at the time of molding, the peripheral wall portion We of the material W is formed between the upper end of the tooth forming surface 53 of the die 51 and the tip of the punch 52. A large tensile stress f acts and the peripheral wall portion We of the material W extends in the axial direction. Therefore, there is a problem that a tapered sink is generated on the tooth crest surface of the molded tooth profile portion T, and an accurate tooth crest shape cannot be obtained.

The object of the present invention is to obtain a ring-shaped product having a precise tooth profile by plastic working, thereby shortening the processing time, improving the material yield, and reducing the processing cost. The present invention provides a cold forming method and a molding die.

[0006]

The molding die of the present invention comprises:
A molding die for plastically working a toothed ring-shaped product having a tooth profile on at least one of an outer diameter surface and an inner diameter surface, which has the following configuration. That is, this molding die is provided on at least one of the inner diameter surface and the outer diameter surface with a tooth forming projection corresponding to the valley shape between the teeth of the tooth profile of the ring-shaped product, and between these tooth forming projections. And a tooth tip shaping protrusion that narrows down the tooth tip surface of the tooth. The molding method of the present invention is a method of plastically working the ring-shaped product using the molding die, wherein the ring-shaped material is axially pushed through the molding die.

[0007]

According to this molding method and the molding die, at least one of the inner diameter surface and the outer diameter surface of the ring-shaped material is the tooth molding protrusion of the molding die by pushing the ring-shaped material through the molding die. It is dusted and formed into a tooth profile. At the initial stage of this molding, the tooth tips of the ring-shaped material tend to be tapered, and the tooth tips of the sinkers are trimmed to a predetermined height by tooth tip shaping projections. Therefore, an accurate tooth profile can be obtained.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described with reference to FIGS. In this embodiment, as shown in FIG. 1 (C), a ring-shaped product W0 having a toothed portion T on its outer diameter surface is plastically worked from a ring-shaped material W, which is a cylindrical raw material. The material of the ring-shaped material W is a mild steel material or a stainless material. In this method, a ring-shaped die 1 and a round shaft-shaped punch 2 are used as a molding die. The die 1 is installed on the die holder 3, and the punch 2 is moved up and down with respect to the die 1 by a driving device. The die 1 is positioned below the inner diameter surface 1a having a cylindrical shape and located between the tooth forming protrusions 4 corresponding to the shape of the valleys between the teeth of the tooth profile T of the ring-shaped product W0 and between these tooth forming protrusions. A tooth tip shaping projection 5 is provided. The inner diameter of the die 1 is a diameter with which the ring-shaped material W is loosely fitted.

The tooth forming projections 4 are provided at a constant pitch in the circumferential direction and have a trapezoidal cross section. As shown in the enlarged view of FIG. 2 (B), the vertical cross-sectional shape of the tooth forming projection 4 is such that the upper portion 4a of the tip end surface of the projection is formed in an arc shape with a radius R1 that gradually projects from the inner diameter surface 1a, 4b is formed in a straight line extending parallel to the axial direction. Projection height h of the tooth forming protrusion 4
1 is a height at which the tip end surface of the tooth forming protrusion 4 substantially matches the root diameter of the ring-shaped product W0.

The tooth top shaping projection 5 is provided so as to extend below the tooth shaping projection 4 from the axially intermediate portion of the tooth shaping projection 4. As for the vertical cross-sectional shape of the tooth tip shaping protrusion 5, the upper portion 5a of the tip end surface of the protrusion is formed in an arc shape with a radius R2 that gradually protrudes from the inner diameter surface 1a, and the lower portion 5b is formed in a straight line extending parallel to the axial direction. ing. A portion 5c of the tooth tip shaping protrusion 5 that protrudes below the tooth forming protrusion 4 may be formed in a cylindrical surface shape that follows the entire circumference of the die 1.
It may be extended by a width of four. The protrusion height of the tooth tip shaping protrusion 5 is set such that the height difference h2 from the tooth shaping protrusion 4 is substantially equal to the tooth height of the ring-shaped product W0.

As shown in FIG. 1, the punch 2 has a stepped round shaft shape, and the stepped surface of the shoulder portion is the pressing surface 2c. The small-diameter tip portion 2a of the punch 2 has a diameter that fits into the inner diameter surface of the ring-shaped material W, and the large-diameter body portion 2b has a diameter slightly smaller than the inner diameter surface of the die 1.

Next, the molding method will be described. In this method, the ring-shaped material W is sequentially pushed into the die 1, and several pieces of the material W in the process of being processed are left in the die 1 to perform extrusion processing. That is, the ring-shaped material W is placed in the die 1.
One piece of the ring-shaped material W is pushed by the punch 2 at a height corresponding to the thickness of one piece of the ring-shaped material W, so that the material W that has been put in the middle of processing and remains in the die 1 is finished product. One toothed ring-shaped product W0 is discharged under the die 1.

By performing the extrusion as described above, the outer diameter portion of the material W is squeezed by the tooth forming projection 4 to have a tooth shape. In this case, as shown in FIG. 3 (A), the outer diameter surface Wa of the material W tends to be tapered in the initial stage of processing, but the recessed outer diameter surface Wa is the tooth tip shaping protrusion 5. It is squeezed and adjusted to a predetermined diameter. Therefore, an accurate tooth profile can be obtained.

When the tooth profile of the ring-shaped product W0 has a high tooth height, the outer diameter surface Wa is largely retracted. In this case, an accurate tooth profile can be obtained by increasing the protrusion height of the tooth tip shaping protrusion 5 as shown in FIG. That is, the height difference h2 between the protrusions 4 and 5 with respect to the protrusion height h1 of the tooth forming protrusion 4 is reduced. In this molding method,
Since a compressive load in the axial direction acts on the material W during molding,
The degree of sinking of the outer diameter surface Wa shown in FIG. 3A is smaller than that in the proposed example of FIG. Therefore, the tooth tip shaping protrusion 5
It is easy to increase the tooth height of the tooth profile portion T in combination with the provision of.

According to the molding method and the molding die, the ring-shaped product W0 having the accurate tooth profile by the plastic working as described above.
Can be obtained. Therefore, the processing time is shortened,
It improves the material yield and reduces the processing cost.

5 to 7 show a method of molding a ring-shaped product W1 having a tooth-shaped portion T on the inner diameter surface as shown in FIG. 5 (B). In this case, as a molding die, a round shaft-shaped lower punch 11 having a tooth forming protrusion 4 and a tooth top shaping protrusion 5 on the outer diameter surface thereof.
And an upper punch 12 having a tubular portion 12a at its tip, and a ring-shaped die 13. These upper and lower punch 1
1, 12 and the die 13 are arranged concentrically. The lower punch 11 is simply placed on the upper surface of the press receiving plate 14.
The die 13 is supported by a plurality of guide rods 15 provided upright on the press receiving plate 14 so as to be able to move up and down, and is urged to a predetermined height (height shown in FIG. 6) by a return spring 16. The lower punch 11 is shown in an enlarged manner in FIG. 7, but the tooth forming protrusions 4 and the addendum shaping protrusions 5 have the same shape as the example of FIG. 1. Reference numerals R1 ′ and R2 ′ in FIG. 2B indicate the radii of the upper tip surfaces of the tooth forming protrusions 4 and the tip shaping protrusions 5, respectively, and h1 ′ and h2 ′ are the protrusion heights of the tooth forming protrusions 4, respectively. And the difference in height between the protrusions 4 and 5.

The molding procedure is the same as above, and the lower punch 1
The ring-shaped material W is sequentially pushed between the die 1 and the die 13, and several pieces of the material W that are being processed are left inside to perform extrusion processing. After forming, when the upper punch 12 is raised as shown in FIG. 6, the die 13, the material W in the process of processing, and the lower punch 11 are formed.
Are lifted together due to the urging of the return spring 16 and the friction of the contact surface, and the finished toothed ring-shaped product W1 remains on the press receiving plate 14. Therefore, the ring-shaped product W1 can be discharged to the outside.

According to this method, the material W is squeezed by the tooth forming projection 4 of the lower punch 11 to form the inner diameter portion into a tooth shape, and the inner diameter surface of the material W at the initial stage of processing is reduced in the same manner as described above. Thus, the tooth profile is adjusted to an accurate shape by the tooth top shaping projection 5. When the tooth height of the ring-shaped product W1 is deep,
As in the example of FIG. 4, by increasing the protrusion height of the tooth top shaping protrusion 5, it is possible to form an accurate tooth profile.

FIG. 8 shows still another embodiment. In this example, the tooth profile T is formed on both the inner diameter surface and the outer diameter surface of the ring-shaped product W2.
Is a method of molding. In this method, the die 1 of FIG.
In place of 3, a die 13 'having a tooth forming protrusion 4 and a tooth top shaping protrusion 5 on the inner diameter surface is used. The tooth forming protrusion 4 and the tooth top shaping protrusion 5 have the same shape as the example of FIG. 1. Other configurations of the molding die are the same as those in the example of FIG. The molding procedure and the method of discharging the finished ring-shaped product W2 are the same as those in the example of FIG. By using this molding die, the tooth profile T is simultaneously molded on both inner and outer surfaces of the material W.

In each of the above-mentioned embodiments, several raw materials W are left in the molding die and the ones put in order are discharged one by one. You may make it complete | finish the process by putting in it, and after that, you may put in the next one raw material W and process it. In that case, punch 2,12
Has a shape such that the tip does not interfere with the tooth forming protrusion 4.

[0021]

As described above, the present invention provides, as a molding die, at least one of the inner diameter surface and the outer diameter surface of a toothed ring-shaped product, which corresponds to the shape of the valley between the teeth, and the tooth molding projections. It is a method of pushing the ring-shaped material through this molding die using a tooth-shaping projection that is provided between the projections and that narrows the tooth tip surface of the tooth, so it has an accurate tooth profile by plastic working. A ring-shaped product can be obtained. Therefore, the processing time is shortened, the material yield is improved, and the processing cost is reduced.

[Brief description of drawings]

FIG. 1 is a sectional view of each operation process of a molding die according to an embodiment of the present invention, and a partial plan view of a ring-shaped product.

FIG. 2A is a partially enlarged plan view of the molding die,
(B) is an enlarged sectional view of the same portion.

FIG. 3 is an operation explanatory view of the molding method.

FIG. 4 is a partial cross-sectional view of a molding die according to another embodiment of the present invention.

FIG. 5 is a cross-sectional view of a molding die and a partial plan view of a ring-shaped product according to still another embodiment of the present invention.

FIG. 6 is a cross-sectional view showing a different operation state of the molding die.

FIG. 7A is a partially enlarged plan view of the molding die, and FIG.
FIG. 4 is an enlarged sectional view of the same.

FIG. 8 is a sectional view of a molding die according to still another embodiment of the present invention.

FIG. 9 is a cross-sectional view showing a proposed example of a cold forming method for a toothed ring-shaped product.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Die, 2 ... Punch, 4 ... Tooth forming protrusion, 5 ... Tooth shaping protrusion, 11 ... Lower punch, 12 ... Upper punch, 13, 1
3 '... Die, W ... Ring material, W0-W2 ... Ring-shaped product with tooth profile, T ... Tooth profile

Claims (2)

[Claims] 1. A method for plastically forming a toothed ring-shaped product having a tooth profile on at least one of an outer diameter surface and an inner diameter surface, wherein the ring shape is formed on at least one of the inner diameter surface and the outer diameter surface of a molding die. A molding die having tooth-forming protrusions corresponding to the valley shape between the teeth of the tooth profile of the product, and tooth-tip shaping protrusions provided between these tooth-forming protrusions to squeeze the tooth tip surfaces of the teeth. A cold forming method for a ring-shaped product with teeth, which is prepared and is formed by pushing a ring-shaped material through the molding die in the axial direction. 2. A molding die for plastically working a toothed ring-shaped article having a tooth profile on at least one of an outer diameter surface and an inner diameter surface, wherein at least one of the inner diameter surface and the outer diameter surface comprises:
Molding having tooth-forming protrusions corresponding to the valley shape between the teeth of the ring-shaped product and tooth-tip shaping protrusions provided between the tooth-forming protrusions to narrow the tooth tip surfaces of the teeth. Mold.