JPH079066A - Extrusion forming apparatus - Google Patents

Abstract

PURPOSE:To form an inner tooth having a prescribed shape without needing a large working pressure by arranging the preceding expanding part showing the cross sectional shape disinverted into negative to an inner tooth gear having the prescribed shape and the finish expanding part showing the cross sectional shape corresponding to the inner tooth gear on a madrel. CONSTITUTION:When a cylindrical work W fitted to a guide part 20A of the mandrel 20 descends with a working pressure of a punch 30, a center hole Wa in the work W is expanded with the preceding expanding part 20B of the mandrel 20. As each spline 20a for forming the inner tooth in the preceding expanding part 20B is formed at small outer and inner diameters and cross sectional shape, the center hole Wa in the work W is expanded without needing the large working pressure. When the work W further descends, the center hole Wa is expanded with the finish expanded part 20C of the mandrel 20, but as the work W is passed through the preceding expanding part 20B, the blank of the work W is easily and surely filled into gap of the spline 20a for forming the inner tooth in the finish expanding part 20C.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an extrusion molding apparatus,
More specifically, it comprises a container for holding the outer circumference of the cylindrical work and a mandrel having a plurality of splines for forming internal teeth on the outer circumference, and extrusion molding for forming inner teeth on the inner peripheral surface of the cylindrical work. Regarding the device.

[0002]

2. Description of the Related Art When manufacturing internal gears by forming internal teeth on the inner peripheral surface of a cylindrical work, a conventional gear cutting machine such as a gear shaver has been generally used. Is extremely long, which causes an increase in production cost. When forming internal teeth (inner splines) that fit with the spline shaft on the inner peripheral surface of a cylindrical work, a broaching machine is usually used. Since the work of removing the powder is required, the production efficiency is poor, and particularly in the case of a work long in the axial direction, there is a disadvantage that the workability is deteriorated due to an increase in cutting resistance.
As a processing method for solving the above-mentioned inconvenience, cold working using an extrusion molding apparatus comprising a container for holding the outer circumference of a cylindrical work and a mandrel provided with a plurality of internal tooth forming splines on the outer circumference An extrusion method is provided.

[0003]

By the way, when the above-mentioned internal gear or inner spline is formed by the above-mentioned extrusion molding apparatus, the material of the work is completely filled in the gap between the internal tooth-forming splines in the mandrel. Therefore, it is necessary to increase the cross-sectional reduction rate of the work at the time of extrusion processing, and thus it is necessary to apply a large processing pressure to the work. Therefore, while the applied processing pressure may cause damage to each part of the extrusion molding apparatus, even if a large processing pressure is applied, sufficient filling of the work material is not performed, and the internal teeth of the desired predetermined shape are not filled. Sometimes I couldn't get an (inner spline). The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an extrusion molding apparatus capable of forming internal teeth of a predetermined shape on the inner peripheral surface of a cylindrical work without requiring a large processing pressure.

[0004]

Therefore, in the extrusion molding apparatus according to the present invention, the mandrel is provided with a preceding expansion portion having a cross-sectional shape negatively displaced with respect to the internal gear having a predetermined shape formed on the cylindrical work. The above-described object is achieved by providing a finishing extension portion having a cross-sectional shape corresponding to the internal gear having a predetermined shape formed on the cylindrical work.

[0005]

According to the above construction, in the preceding expansion portion, since the expansion portion has a cross-sectional shape that is negatively displaced with respect to the internal gear having a predetermined shape, the inner circumference of the work is not required without a large processing pressure. The surface can be expanded, and the finish expansion part is sufficiently filled because the material of the work piece easily flows by passing through the preceding expansion part.

[0006]

The present invention will be described in detail below with reference to the drawings illustrating the embodiments. FIG. 1 shows an example in which the extrusion molding apparatus according to the present invention is applied to an extrusion molding apparatus for forming an internal gear from a cylindrical work. This extrusion molding apparatus 1
Includes a container 10 having an annular shape, a mandrel 20 erected so as to pass through a guide hole 10a in the container 10, and a punch 30 for applying a processing pressure to the cylindrical work W. .

On the other hand, as shown in FIG. 7 (a), the cylindrical work W before processing has a thick cylindrical shape with a central hole Wa formed therein, and is made of a cold material such as a steel material or an aluminum material. It is made of any material selected from the materials that can be extruded, considering the shape (size) and strength of the internal gear to be manufactured. The tubular work W is shaped into an internal gear (block) B having a shape as shown in FIG. 7B by the extrusion molding device 1, and then finished to an appropriate size to be a product. In this embodiment, the specifications of the internal gear formed on the cylindrical work W are m (module).
= 1.0, Z (number of teeth) = 14, d (standard pitch circle diameter) = 14m
m, dk (tooth circle) = 17 mm, h (tooth) = 2.0 mm, x
(Dislocation coefficient) = + 0.5, or m = 1.5, Z = 13, d = 1
Although 9.5 mm, dk = 24 mm, h = 3.375 mm, and x = + 0.05, it is needless to say that the extrusion molding apparatus 1 can form an internal gear having arbitrary specifications.

As shown in FIGS. 1 to 3, the mandrel 20 of the extrusion molding apparatus 1 has a cylindrical work W insertion side,
That is, a guide portion 20A, a preceding expansion portion 20B, and a finishing expansion portion 20C are provided in order from the upper side in FIG. 1 (the left side in FIGS. 2 and 3), and the guide portion 20A is the center of the tubular work W. While forming a cylindrical shape having an outer diameter dimension that fits into the hole Wa, the preceding expansion portion 20B and the finish expansion portion 2 are formed.
On the outer periphery of 0C, a plurality of internal spline 2 for internal tooth formation is drawn in a manner of drawing a straight line along the longitudinal axis of the mandrel 20.
0a, 20a, ... Are extended.

As shown in FIG. 2, the preceding expansion portion 20B is provided.
Is a taper portion 20Ba connected from the guide portion 20A,
Straight portion 20 extending along the axis of the mandrel 20
Bb, and the taper portion 20Ba has about 1
An inclination angle θb of 5 ° is provided. On the other hand, the finishing extension portion 20C is the straight portion 20B of the preceding extension portion 20B.
It has a taper portion 20Ca continuous from b and a straight portion 20Cb extending along the axis of the mandrel 20, and the taper portion 20Ca is provided with an inclination angle θc of 15 °.

The advance expansion portion 20B of the mandrel 20
Has a cross-sectional shape that is negatively displaced with respect to the internal gear having a predetermined shape to be formed on the cylindrical work W, while the finish expansion portion 20C has a cross-sectional shape corresponding to the internal gear having the predetermined shape. Is presenting. That is, as is apparent from FIG. 4, each internal tooth shaping spline 20a in the preceding expansion portion 20B has the same internal tooth gear and module as the above-described predetermined shape, in other words, the same central angle, and the predetermined shape. The outer diameter and inner diameter (valley diameter) of each spline 20a of the finish expansion portion 20C formed corresponding to the internal gear are small, and the cross-sectional shape of each of the splines 20a is also small. It is formed smaller than the internal tooth shaping spline 20a.

Further, as clearly shown in FIG. 3, each internal tooth forming spline 20a, 2 in the preceding expansion portion 20B is formed.
The diameter db of the valley surface of 0a, ... Is slightly smaller than the outer diameter da of the guide portion 20A, while the splines 20a, 20a ,.
The diameter dc of the valley surface is larger than the outer diameter da of the guide portion 20A, and the splines 20a, 20 in the taper portion 20Ca of the finish expansion portion 20C are formed.
The valley surface 20b of a, ... Is composed of a smooth curved surface with a radius of curvature of about 15 mm. Further, the straight portion 20Bb of the preceding expansion portion 20B is formed to have a length of about 5 mm along the axis of the mandrel 20, while the length of the tubular work W constrained between the container 10 and the mandrel 20. The height H (Fig. 1) is set to about 5 mm. It should be noted that the outer diameter dimension of each portion of the mandrel 20 described above, the inclination angle of each tapered portion, the restraint length H, and the like can be arbitrarily set according to the desired product (internal gear). Needless to say.

In order to form the internal gear from the cylindrical work W by the extrusion molding apparatus 1 described above, first, as shown in FIG. 1, the cylindrical work W is accommodated in the guide hole 10a of the container 10 and the mandrel 20 is held. After being mounted on the guide portion 20A, the punch 30 pressurizes and lowers the cylindrical work W, and then, as shown in FIG. 6A, a new cylindrical work W is mounted above the work W, By pressing the cylindrical work W again with the punch 30, the cylindrical work W is cold extruded between the container 10 and the mandrel 20 as shown in FIG. 6B, and the internal gear (block ) B is formed.

Here, the guide portion 20A of the mandrel 20
When the cylindrical work W mounted on the cylindrical work W is lowered by the processing pressure of the punch 30, the center hole W in the cylindrical work W is
First, a is expanded by the preceding expansion portion 20B of the mandrel 20, and as described above, the preceding expansion portion 20B is expanded.
Since each internal tooth forming spline 20a in FIG. 2 is formed to have a negative dislocation with respect to the internal gear having a predetermined shape to be formed, that is, the outer inner diameter and the cross-sectional shape are small, the center hole Wa in the cylindrical work W is Therefore, it can be expanded without requiring a large processing pressure.

When the center hole Wa of the cylindrical work W is expanded by the internal tooth shaping splines 20a, 20a of the preceding expansion portion 20B, the internal work molding splines 20a, 20a, A split flow is generated toward the bottom between the portions 20a, which increases the degree of freedom of material flow and facilitates the flow of the material of the cylindrical work W.

When the cylindrical work W is further lowered, the center hole Wa in the cylindrical work W is expanded by the finish expanding portion 20C of the mandrel 20, and the material of the cylindrical work W is as described above. Since the fluid has become easy to flow by passing through the preceding expansion portion 20B, the internal tooth forming splines 20a, 20a in the finish expansion portion 20C.
The material of the cylindrical work W is easily and surely filled between them.

As described above, according to the extrusion molding apparatus 1, the cylindrical work W does not require a large processing pressure.
Inner teeth of a predetermined shape can be formed on the inner peripheral surface of the. In addition, the work of mounting the cylindrical work W on the mandrel 20
Alternatively, the work of taking out the internal gear B is performed by, for example, the container 1
Needless to say, it can be easily implemented by adopting an appropriate means such as a structure in which 0 and the mandrel 20 are relatively separated in the vertical direction.

In the extrusion molding apparatus 1, the mandrel 120 shown in FIG. 5 is used in place of the mandrel 20 described above, so that not only the internal teeth of the internal gear but also the spline shaft on the inner peripheral surface of the work W is formed. It is also possible to form the fitting inner teeth (inner spline). The mandrel 120 is basically the same as the mandrel 20 described above except that the internal tooth forming spline 120a has a substantially rectangular cross-sectional shape as shown in FIG. That is, each internal tooth shaping spline 120 in the preceding expansion portion 120B.
a is formed at the same center angle as each inner spline to be formed on the cylindrical work W, and is different from each spline 120a of the finish extending portion 120C formed corresponding to each inner spline. The outer diameter and the root diameter of the spline 1 are small, and the cross-sectional shape of the spline 1 for forming each internal tooth in the finished expansion portion 120C is also small.
It is formed smaller than 20a. Also in the extrusion molding apparatus using the mandrel 120, similarly to the extrusion molding apparatus 1 described above, an inner spline of a predetermined shape can be formed on the inner peripheral surface of the cylindrical work W without requiring a large processing pressure.

The mandrel 20 'of the extrusion molding apparatus 1'shown in FIG. 8 has a leading extension 20B' and a finish extension 2 '.
A plurality of internal tooth-forming splines 20a ', 20a', ... Are extended in a manner of drawing a spiral around the longitudinal axis of the mandrel 20 'on the outer periphery of 0C'. According to 1 ', the inner helical gear is formed from the work W'. The configuration of the mandrel 20 'is basically the same as that of the mandrel 20 described above except that the internal tooth forming spline 20a' is formed in a spiral shape. That is, the mandrel 20 ′ has the guide portion 20.
A ', the preceding expansion portion 20B', and the finishing expansion portion 20C '
In addition, the preceding expansion portion 20B 'is formed in a cross-sectional shape that is negatively displaced with respect to the internal gear (inner helical gear) of a predetermined shape to be formed on the cylindrical work W', while The finish expansion portion 20C 'is formed in a cross-sectional shape corresponding to the internal gear (inner helical gear) having the predetermined shape. The extrusion forming apparatus 1 '
Since the configuration other than the mandrel 20 'in FIG. 2 is basically the same as that of the extrusion forming apparatus 1 described above, the elements having the same functions as those of the extrusion forming apparatus 1'in the extrusion forming apparatus 1'are indicated by a number' (dash). Is attached and detailed description is omitted.

According to the extrusion forming apparatus 1 ', similarly to the extrusion forming apparatus 1 described above, after the cylindrical work W'is mounted on the guide portion 20A' of the mandrel 20 ', it is pressurized and lowered by the punch 30'. By repeating the step of making, the cylindrical work W ′ is formed into the spline 2 for forming each internal tooth.
Cold extrusion is carried out while rotating following 0a, so that an inner helical gear (block) B'is formed. At this time, the central hole Wa 'of the cylindrical work W'is provided with the preceding expanded portion 20B' and the finished expanded portion 20C 'of the mandrel 20'.
Since it is expanded stepwise through and, like the case of forming the internal gear by the extrusion molding apparatus 1 as described above,
Spiral teeth of a predetermined shape are formed on the inner peripheral surface of the cylindrical work W ′ without requiring a large processing pressure, so that the inner helical gear (block) B ′ is formed from the cylindrical work W. When the mandrel 20 'is rotatably installed about its longitudinal axis and the cylindrical work W'is pushed down by the punch 30', the mandrel 20 'side with respect to the cylindrical work W'is pressed. It can also be configured to rotate.

On the other hand, in the extrusion manufacturing apparatus 1'having the above structure, the spline 20 for forming each internal tooth of the mandrel 20 '.
By making a'substantially rectangular in cross-sectional shape like the mandrel 120 shown in FIG. 5, not only the helical teeth of the inner helical gear but also the inner teeth (inner inner) that fit with the helical spline shaft on the inner peripheral surface of the work W. It is also possible to form a helical spline), and even with the above configuration, a product having a predetermined shape can be obtained without requiring a large processing pressure, as in the extrusion manufacturing apparatus 1'described above.

In each of the above-mentioned embodiments, the mandrel provided with only two expansion parts, the preceding expansion part and the finishing expansion part, has been exemplified, but an intermediate mandrel is provided between the preceding expansion part and the finishing expansion part. It is also possible to provide a mandrel having three or more expanding parts by providing an expanding part having a cross-sectional shape.

[0022]

As described above in detail, the extrusion molding apparatus according to the present invention includes a preceding expansion portion having a cross-sectional shape negatively displaced with respect to an internal gear having a predetermined shape formed on a cylindrical work. And a finishing extension having a cross-sectional shape corresponding to an internal gear having a predetermined shape formed on the cylindrical work. According to the above configuration, when the tubular work is extruded, a large processing pressure is required in the preceding expansion portion because the expansion portion has a negatively displaced cross-sectional shape with respect to the internal gear having a predetermined shape. It is possible to expand the inner peripheral surface of the work without any problems, and in the finish expansion part, the material of the work becomes easy to flow by passing through the preceding expansion part, so sufficient filling is performed, and thus a large processing pressure is applied. It has become possible to form internal teeth of a predetermined shape on the inner peripheral surface of the cylindrical work without requiring.

[Brief description of drawings]

FIG. 1 is a conceptual overall cross-sectional side view of an extrusion molding apparatus according to the present invention.

FIG. 2 is a side view of essential parts showing a mandrel of an extrusion molding apparatus according to the present invention.

FIG. 3 is a cross-sectional side view of essential parts showing a mandrel of an extrusion molding apparatus according to the present invention.

FIG. 4 is a sectional view taken along line AA in FIG.

FIG. 5 is a cross-sectional front view of essential parts showing another embodiment of the mandrel in the extrusion molding apparatus according to the present invention.

6 (a) and 6 (b) are conceptual overall cross-sectional side views showing an operation mode of the extrusion molding apparatus according to the present invention.

7A and 7B are overall perspective views showing a cylindrical work before processing and an internal gear block after processing which are applied to the extrusion molding apparatus according to the present invention.

FIG. 8 is a conceptual overall cross-sectional side view showing another embodiment of the extrusion molding apparatus according to the present invention.

[Explanation of symbols]

 1, 1 '... Extrusion molding device, 10, 10' ... Container, 20, 20'120 ... Mandrel, 20a, 20a'120a ... Spline for internal tooth shaping, 20A, 20A '... Guide part, 20B, 20B'120B ... Leading expansion part, 20C, 20C'120C ... Finishing expansion part, 30, 30 '... Punch, W, W' ... Cylindrical work,

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yozo Sawaki 3459-29 Tomitsuka-cho, Hamamatsu City, Shizuoka Prefecture (72) Inventor Yasuo Nagase 1-2-22-6 Hirosawa, Hamamatsu City, Shizuoka Prefecture Inventor Hajime Yoshida Hamana, Shizuoka Prefecture 7790-2, Ufumi, Yuuto-cho, Gunma (72) Inventor Mitsumasa Akahoshi 300, Takatsuka-cho, Hamamatsu City, Shizuoka Prefecture Suzuki Stock Company

Claims (2)

[Claims] 1. A container for holding an outer circumference of a cylindrical work, and a mandrel having a plurality of splines for forming internal teeth on the outer circumference, wherein inner teeth are provided over the entire inner circumference of the cylindrical work. An extrusion molding device for forming, wherein a plurality of internal tooth forming splines extending on the outer periphery in a manner of drawing a straight line along a longitudinal axis, and internal teeth of a predetermined shape formed on the cylindrical work. A mandrel having a preceding expansion portion having a cross-sectional shape displaced negatively with respect to the gear and a finishing expansion portion having a cross-sectional shape corresponding to the internal gear having a predetermined shape formed on the cylindrical work. An extrusion molding device characterized by: 2. A container for holding an outer circumference of a cylindrical work, and a mandrel having a plurality of splines for forming internal teeth on the outer circumference, wherein inner teeth are formed over the entire inner circumference of the cylindrical work. And a plurality of internal splines for shaping an internal tooth extending on the outer periphery in a spiral shape around a longitudinal axis, and an internal gear having a predetermined shape formed on the cylindrical work. A mandrel having a preceding expansion portion having a negatively displaced cross-sectional shape and a finishing expansion portion having a cross-sectional shape corresponding to an internal gear having a predetermined shape formed on the cylindrical work. A characteristic extrusion molding device.