JPH0494836A - Manufacture of forming die for forging gear and forming method for gear product by gear molding die - Google Patents

Abstract

PURPOSE:To manufacture a gear forming die having high strength and high accuracy teeth by taper-fitting a cylindrical preform into a die hole through its outer peripheral surface and forcing a master gear having gear teeth on the outer peripheral part from the upper part into the axial center part. CONSTITUTION:The preform 1 forming a hole 2 of the axial center part in equal diameter and an outer peripheral surface 3 which is smaller in diameter to the lower part is taper-fitted into the 1st die hole 11 of the 1st die 10 through its outer peripheral surface 3. A 1st master gear 15 is lowered through a ram to force gear teeth 16 into the hole 2 of the preform 1. An intermediate gear forming die 5 having gear teeth 6 is formed by a compression force to the inside in the radius direction through this 1st die hole 11 and by a pressure to the outside in the radial direction through the gear teeth 16. Thereafter, this intermediate gear forming die 5 is compressed by the 2nd master gear teeth to obtain the gear forming die having high strength and high accuracy teeth. The intermediate gear product is compressed by this gear forming die in the axial direction to obtain a gear product having high strength and high accuracy teeth.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a method for manufacturing a forging gear mold for forming a gear by forging, and a method for molding a gear product using a gear mold manufactured by this manufacturing method. It is related to.

(Prior art) The conventional manufacturing method for gear forming dies for forging involves providing a cylindrical intermediate material with a hole formed in the shaft center, and cutting out the inner periphery of the material by electric discharge machining to form gear teeth. It was something like that.

In addition, the conventional method for forming gear products using a gear mold is to fit a disk-shaped intermediate product into the gear mold formed as described above, compress it in the axial direction, and compress the material in the radial direction. A gear product having gear teeth on the outer periphery is formed by plastically flowing outward and filling the outer periphery into the gear teeth of the gear mold.

(Problems to be Solved by the Invention) In the above-mentioned conventional gear forming die manufacturing method, the metal structure is divided to form gear teeth, which reduces the strength of the teeth and also reduces the machining surface due to electrical discharge machining. There was a drawback that it was difficult to obtain accuracy due to roughness.

In addition, the method of forming gear products using conventional gear molds is as follows:
The material was made to plastically flow outward in the radial direction, and the gear teeth were formed on the outer periphery using only the pressure from this unidirectional plastic flow, which resulted in the disadvantage that the teeth could not be formed with high precision due to the molding pressure difference inside the product. The object of the present invention is to provide a new method for manufacturing a gear mold for forging and a method for molding a gear product using the gear mold, which eliminates the above-mentioned drawbacks.

(Means for Solving the Problems) In order to achieve the above object, the present invention is constructed as follows.

That is, a cylindrical intermediate material whose outer peripheral surface is tapered downward and a hole is formed in the axial center is provided, and the outer peripheral surface of this intermediate material is tapered fitted into the die hole. and slide the intermediate material downward within the die hole,
A master gear having gear teeth formed on its outer periphery is pushed into the axial center of the intermediate material from above.

In addition, a cylindrical intermediate material is provided, the outer circumferential surface of which is tapered downward and a hole is formed in the axial center, and this intermediate material is tapered into the first die hole on the outer circumferential surface. After fitting and sliding the intermediate material downward in the first die hole, a first master gear having gear teeth formed on the outer periphery is pushed into the axial center of the intermediate material from above and inserted into the inner periphery. An intermediate gear mold with gear teeth formed thereon is provided, and the intermediate gear mold is taper-fitted into the second die hole at its outer peripheral surface, and the second master gear with gear teeth formed on its outer peripheral surface is inserted into the second die hole from above. The intermediate gear mold is press-fitted into the gear teeth of the intermediate gear mold, and the intermediate gear mold is slid downward in the second die hole to be compressed in the radial direction.

Further, a cylindrical first gear forming die having gear teeth formed on the inner circumference is fitted into the hole of the formwork, and the first gear forming die is fitted into the hole of the formwork. A disk-shaped intermediate product is fitted into the first gear mold, and this intermediate product is axially compressed to expand to a large diameter, and its outer periphery is inserted into the gear teeth of the first gear mold. By filling the intermediate gear product with gear teeth on the outer periphery, a cylindrical No. The gear forming die is tapered fitted into the vertical middle part of the hole of the formwork, and
The lower end of the intermediate gear product is engaged with the upper end of the gear molding mold, and the intermediate gear product is slid downward in the gear molding mold II, and the gear molding mold II is inserted into the mold. The intermediate gear product is slid downward through the hole, and then the intermediate gear product is compressed in the axial direction.

(Function) Since the present invention has the above configuration, the intermediate material is
Gear teeth are formed on the inner circumference by radially inward pressure by the die hole and radially outward pressure by the master gear.

Furthermore, gear teeth are finished formed on the inner circumference of the intermediate gear mold by the radially inward pressing force applied by the second die hole.

In addition, the gear product is produced by a two-directional force consisting of the radially inward pressing force of the gear molding die II and the radially outward plastic flow of the intermediate gear product due to axial compression. Gear teeth will be formed on the outer periphery.

(Example) Embodiments of the present invention will be described below based on the drawings.

In the drawings, FIGS. 1 to 4 are cross-sectional views of the first to fourth steps showing the first gear mold manufacturing method according to the present invention, and FIGS. 5 to 8 are cross-sectional views of the second gear mold manufacturing method according to the present invention. Cross-sectional views of the first to fourth steps showing the gear mold manufacturing method, FIGS.
FIG. 12 is a cross-sectional view of the first to fourth steps showing a method for forming a gear product using a gear mold according to the present invention.

First, a method for manufacturing the first gear mold will be described.

In FIG. 1, reference numeral 1 denotes a metal intermediate material formed by turning, in which a hole 2 in the axial center is formed to have the same diameter, and an outer circumferential surface 3 is formed into a tapered surface with a smaller diameter at the bottom. The outer circumferential surface 3 is formed into a stepped tapered surface having a stepped portion 4 at an intermediate portion in the vertical direction.

The outer peripheral surface 3 of the intermediate material 1 is fit into a first die hole 11 formed in the first die 1o in a tapered manner.

The first die hole 11 is formed to have a tapered surface with a smaller diameter at the bottom, and has a length in the vertical direction longer than the width in the vertical direction of the intermediate material 1. 1 is fitted and held. The first die 10 is supported on the machine by a base 12, and the base 12 has a pin hole with a slightly larger diameter than the hole 2 of the intermediate material 1 at its axial center.
It has 3.

A first master gear 15 is pushed downward by a ram (not shown), and the first master gear 15 has gear teeth 16 on its outer periphery.

The gear teeth 16 are formed by cutting with a gear cutting machine, and then heat treated and polished to a high precision finish.

Reference numeral 17 denotes a cylindrical guide fitted and locked in the upper part of the first die hole 11, which guides the first master gear 15 and regulates the lowest movement position of the ram to guide the first master gear 15.
Determine the lowest position.

When processing the intermediate material 1, first the cylindrical plug 18 is press-fitted into the hole 2 of the intermediate material 1, and its lower end is fitted into the upper part of the pin hole 13 of the base 12.

In this state, as shown in FIG. 2, the first master gear 15 is lowered via the ram and pushed into the axial center of the intermediate material 1, and the gear teeth 16 of the first master gear 15 are inserted into the hole 2 of the intermediate material 1.
while pushing the intermediate material 1 into the first
The ram is slid downward along the die hole 11 and brought into contact with the upper surface of the base 12, and when the lower end of the first master gear 15 is located at the vertically intermediate portion of the hole 2, the ram is brought into contact with the guide 17. The lowering of the first master gear 15 is stopped.

Then, the intermediate material 1 is subjected to two directions of force consisting of a radially inward pressing force by the first die hole 11 and a radially outward pressing force by the gear teeth 16 of the first master gear 15. Gear teeth 6 are formed on the inner periphery of the upper half, and an intermediate gear mold 5 having the gear teeth 6 is formed.

The plug 18 is moved from the hole 2 to the pin hole 13 by the lowering of the first master gear 15, and the plug 18 is moved from the hole 2 to the pin hole 13 by the lowering of the first master gear
This is to restrict self-movement of the intermediate material 1 in the axial direction when forming the gear teeth by the step 5.

Next, as shown in FIG. 3, a second master gear 25, which will be described later, is press-fitted into gear teeth 6 of the intermediate gear mold 5, and
The outer circumferential surface 7 thereof is tapered fitted into the second die hole 21 of the second die 20 .

Like the first die hole 11 described above, the second die hole 21 is formed into a tapered surface with a smaller diameter at the bottom, and the intermediate gear mold 5 is fitted and held at the lower part of the second die hole 21. .

The second die 20 is supported on the machine by a base 22,
The base 22 has a recess 23 at its axial center into which the lower part of the intermediate gear mold 5 can fit.

Further, the second master gear 25 has high-precision gear teeth 26 on its outer periphery, similar to the first master gear 15 described above.
are formed, and the gear teeth 26 are press-fitted and meshed with the gear teeth 6 of the intermediate gear mold 5 as described above.

27 is a guide which is fitted into the upper part of the second die hole 21 and whose lower end is brought into contact with the upper surface of the intermediate gear mold 5;
The upper end of the second master gear 25 is made to protrude upwardly than the upper end of the second master gear 25, and a large diameter stepped portion 27-1 formed on the outer periphery is connected to the second master gear 25.
It is spaced apart from the upper surface of the die 20 by a predetermined amount.

Then, as shown in FIG. 4, the guide 27 is lowered via the ram to slide the intermediate gear mold 5 downward along the second die hole 21, and the second master gear 25 and the second die hole 21 to compress the intermediate gear mold 5 in the radial direction,
A second gear mold 8 having finished gear teeth 9 on its inner circumference is formed.

Next, a method for manufacturing the second gear mold will be described.

In FIG. 5, reference numeral 1a denotes a metal intermediate material formed by turning, in which a hole 2a in the axial center is formed to have the same diameter, and an outer circumferential surface 3a is formed into a tapered surface with a smaller diameter at the bottom.

The intermediate material 1a is placed at the outer peripheral surface 3a of the first die 10.
It is tapered and fitted into the vertically intermediate portion of the first die hole 11a formed in the first die hole 11a.

The first die 10a is supported by a base 12a, and the base 12a has a pin hole 13a at its axial center, which has a slightly larger diameter than the hole 2a of the intermediate material 1a.

Reference numeral 15a denotes a first master gear that is pressed downward by a ram, and this first master gear 15a has gear teeth 16a on its outer periphery, and has a cylindrical plug part 18a integrally below the gear teeth 16a. .

The gear teeth 16a are formed by cutting with a gear cutter, and then heat treated and polished to a high precision finish.

Reference numeral 17a denotes a cylindrical guide, which is fitted and locked into the upper end of the first die hole 11a, guides the first master gear 15a, and regulates the lowest movement position of the ram to guide the first master gear 15a. Determine the lowest position.

When processing the intermediate material 1a, as shown in FIG. in this state, the gear teeth 16a of the first master gear 15a are brought into contact with the upper surface of the base 12a, and in this state, the gear teeth 16a of the first master gear 15a are
a into the hole 2a, so that the lower end of the gear tooth 16a is in the hole 2a.
When the first master gear 15a is located at the lower end, the upper end of the guide 17a restricts the downward movement of the ram, thereby stopping the first master gear 15a from descending.

Then, the intermediate material 1a is subjected to two directions of force consisting of a radially inward pressing force by the first die hole 11a and a radially outward pressing force by the gear teeth 16a of the first master gear 15a. Gear teeth 6a are formed on the inner peripheral portion leaving the lower end portion, and an intermediate gear mold 5a having the gear teeth 6a is formed.

The plug portion 18a is for restricting self-movement of the intermediate material 1a in the axial direction when the first master gear 15 forms gear teeth.

Next, after removing the lower end of the intermediate gear mold 5a,
As shown in FIG. 7, the gear teeth 6a are press-fitted into the gear teeth 26a of a second master gear, which will be described later, and fit into the vertical intermediate portion of a tapered second die hole 21a formed in the second die 20a. Stop.

The second die 20a is supported by a base 22a, and the base 22a has a bottle hole 23a similar to the base 12a described above.

Further, the second master gear 25a has high-precision gear teeth 26a formed on its outer periphery in the same way as the first master gear 15a described above, and has a cylindrical trunk 28a integrally formed at the lower part of the gear teeth lea. As described above, the gear teeth 26a are press-fitted and engaged with the gear teeth 6a of the intermediate gear mold 5a.

Reference numeral 27a denotes a guide, which is fitted into the upper part of the second die hole 21a so that its lower end is brought into contact with the upper surface of the intermediate gear mold 5a, its upper end is on the same level as the upper end of the second master gear 25a, and its outer periphery is The large-diameter stepped portion 27a-1 formed in the second die 20a is spaced upward by a predetermined amount from the upper surface of the second die 20a.

Then, as shown in FIG. 8, the second master gear 25a and the guide 27a are lowered via the ram until the step 27a-1 of the guide 27a abuts the upper surface of the second die 20, and the intermediate gear is formed. The mold 5a is slid downward along the second die hole 21a.

This allows the intermediate gear mold 5a to be connected to the second master gear 25.
A and the second die hole 21a form a 1I gear mold 8a which is compressed in the radial direction and has finished gear teeth 9a on its inner circumference.

Next, a method of processing a gear product using the first and second gear forming molds 8.8a described above will be explained.

First, the intermediate gear product 41 is processed using the first gear mold 8 .

In FIG. 9, 30 is a formwork supported by a base 34, and has a hole 31 in its axial center.

The deposit 32 and the aforementioned gear mold 8 are press-fitted into the lower and upper parts of the hole 31, and the first lower mold 33 is press-fitted into the lower part of the gear mold 8. In this case, the first gear forming die 8 is cut into a stepped shape having a small diameter at the top and a large diameter at the bottom, and is press-fitted into the hole 31 of the mold 30.

Next, the intermediate product 40 that has been forged into a disc shape is
It is fitted into the gear mold 8 and placed on the first lower mold 33.

35 is a first punch supported by a ram (not shown), and this first punch 35 includes a cylindrical outer circumference punch 36 having gear teeth on the outer circumference and a shaft-shaped central punch located at its axial center. It consists of 37.

Then, as shown in FIG. 10, the first punch 35 is lowered via the ram and pushed into the axial center of the intermediate product 40.
The first punch 35 and the first lower die 33 compress the intermediate product 40 in the axial direction, that is, in the vertical direction, causing the outer circumferential part to plastically flow outward in the radial direction, and the outer circumferential part is formed into the second gear. It is filled into the gear teeth 9 of the mold 8, thereby forming an intermediate gear product 41 having gear teeth 42 on the outer periphery.

In addition, in FIGS. 9 and 10, 38 is an extrusion rod that extrudes the molded intermediate gear product 41 upward from the first gear mold 8.

Next, the intermediate gear product 41 is finished by the second gear mold 8a.

In FIG. 11, 30a is a formwork supported by a base 34a, and has a tapered hole 3 in the axial center with a smaller diameter at the bottom.
It has 1a.

A cylindrical second lower mold 33a is tapered fitted into the lower part of the hole 31a, and the second gear mold 8a mentioned above is spaced slightly upward from the second lower mold 33a in the upper part of the hole 31a. Taper fit.

Next, the above-mentioned intermediate gear product 41 is turned upside down and engaged with the upper end of the second gear mold 8a.

35a is a cylindrical second punch supported by a ram (not shown), and this second punch 35a has a second punch at its lower part.
A large diameter outer periphery punch 3 that comes into contact with the upper surface of the gear mold 8a
6a, and a small-diameter central punch 37 that protrudes below the outer peripheral punch 36a and contacts the upper surface of the intermediate gear product 41.
It has a and a.

Then, as shown in FIG. 12, the second punch 35a is lowered via the ram, first the intermediate gear product 41 is moved downward in the second gear mold 8a by the central punch 37a, and then the outer peripheral punch 36a, the second gear forming die 8a is slid downward in the hole 31a of the formwork 30a to compress its gear teeth 9a in the axial direction, and then, at the lowest point, the central punch 37a and the second The lower die 33a compresses the outer circumferential portion of the intermediate gear product 41 in the axial direction, causing this portion to plastically flow outward in the radial direction.

As a result, the gear teeth 42 of the intermediate gear product 41 are
The gear product 44 is finished with high precision by two-directional forces: the pressure in the axial direction by the gear teeth 9a of the gear mold 8a of I and the pressure of the plastic flow outward in the radial direction. is formed.

In addition, in FIGS. 11 and 12, 38a is an extrusion iron that pushes out the molded gear product 44 upward from the gear mold 8a.

(Effects of the Invention) As is clear from the above description, according to the present invention, the inner peripheral portion of the intermediate material is compressed from two directions, radially outward and inward, to cause plastic flow. Since it is made to follow the gear teeth, it is possible to obtain a gear-shaped mold having high strength and highly accurate teeth.

In addition, the intermediate gear mold formed as described above is compressed from the outside in the radial direction to press the gear teeth on the inner circumference against the gear teeth of the second master gear, which increases the strength. This has the effect of making it possible to obtain a gear molding die having high and highly accurate teeth.

In addition, an intermediate gear product having gear teeth on the outer periphery is meshed with the gear teeth of a gear mold, and the gear mold compresses the intermediate gear product in the axial direction, and in this state, the intermediate gear product is compressed in the axial direction. As a result, the gear teeth of the intermediate gear product are compressed from two directions, radially outward and inward, and the strength is reduced. It is possible to obtain a gear product having high and highly accurate teeth.

=20-4, Brief description of the drawings ``Figures 1 to 4 are sectional views of the first to fourth steps showing the method for manufacturing a summer gear mold according to the present invention, and Figures 5 to 8 The figure shows the first step to the second gear mold manufacturing method according to the present invention.
A cross-sectional view of the fourth step, and FIGS. 9 to 12 are cross-sectional views of the first to fourth steps showing a method for forming a gear product using a gear mold according to the present invention.

1, la: intermediate material, 2, 2a: hole, 3, 3a outer peripheral surface,
4: Step part, 5, 5a: Intermediate gear mold, 6, 6a: Gear teeth, ? , 7a: outer peripheral surface, 8° 8a: gear molds I and II, 9.9a: gear teeth.

10.10a,: first die, 11. lla: first die hole, 12, 12a: base, 13, 13a,: pin hole, 1
5, 15a: first master gear, 16.16a: gear tooth, 17, 17a guide, 18: plug, 18a: trunk.

20.20a: Second die, 21, 21a: Second die hole, 22, 22a: Base, 23: Recess, 23a pin hole, 25, 25a: Second master gear,: 26, 26a
: Gear tooth, 27, 27a Ni guide, 27-1, 27
a-1: Danbe, 28a: Executive.

30.30a: Formwork, 31, 31a: Hole, 32: Deposit,
33, 33a: 1st. 2nd lower mold, 34. 34a: base, 35, 35a: 1st. 2nd punch, 36, 36a: outer punch, 37° 37a: center punch, 38, 38a:
Extrusion Rondo.

40: Intermediate product, 41: Intermediate gear product, 42: Gear tooth,
44: Gear products.

Application agent: Hisashi Matsumoto (Mano , 4 Ba

Claims (1)

[Scope of Claims] 1. A cylindrical intermediate material whose outer circumferential surface is tapered downward and has a hole formed in its axial center is provided, and this intermediate material is formed on its outer circumferential surface. The intermediate material is tapered fitted into the die hole, and after sliding the intermediate material downward within the die hole, a master gear having gear teeth formed on the outer periphery is pushed into the axial center of the intermediate material from above. A method for manufacturing a gear mold for forging. 2. Provide a cylindrical intermediate material whose outer circumferential surface is tapered downward and has a hole formed in the axial center, and taper the outer circumferential surface of this intermediate material into the first die hole. After fitting and sliding the intermediate material downward in the first die hole, a first master gear having gear teeth formed on the outer periphery is pushed into the axial center of the intermediate material from above and inserted into the inner periphery. An intermediate gear mold with gear teeth formed thereon is provided, and the intermediate gear mold is taper-fitted into the second die hole at its outer peripheral surface, and the second master gear with gear teeth formed on its outer peripheral surface is inserted into the second die hole from above. A method for manufacturing a gear mold for forging, characterized in that the intermediate gear mold is press-fitted into the gear teeth of the intermediate gear mold, and the intermediate gear mold is compressed in the radial direction by sliding the intermediate gear mold downward in a second die hole. . 3. Fit a cylindrical No. I gear mold with gear teeth formed on the inner periphery into the hole of the formwork, and fit the disk-shaped intermediate product into the I-th gear mold. This intermediate product is compressed in the axial direction to expand it to a large diameter, and the outer periphery of the intermediate product is filled into the gear teeth of the gear forming mold I, thereby producing an intermediate gear product having gear teeth on the outer periphery. form,
The outer peripheral surface is formed in a tapered shape that decreases downward,
A cylindrical second gear forming mold with gear teeth formed in the inner center is tapered fitted into the vertical middle part of the hole in the formwork, and
The lower end of the intermediate gear product is engaged with the upper end of the gear mold I, and the intermediate gear product is slid downward in the gear mold II, and the second gear mold is inserted into the mold. A method for molding a gear product using a gear mold, characterized in that the intermediate gear product is slid downward through a hole in a frame, and then the intermediate gear product is compressed in the axial direction.