JPH0688094B2 - Manufacturing method of gear forming die for forging and forming method of gear product by gear forming die - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for manufacturing a gear forming die for forging that forms a gear by forging, and a method for forming a gear product by the gear forming die produced by this manufacturing method. It is about.

(Prior Art) A conventional method for manufacturing a gear forming die for forging is to provide a cylindrical intermediate material having a hole formed in an axial center portion thereof, and cut an inner peripheral portion thereof by electric discharge machining to form gear teeth. It was a thing.

Further, in the conventional method for forming a gear product by a gear forming die, a disc-shaped intermediate product is fitted to the gear forming die formed as described above, and the intermediate product is compressed in the axial direction to make the material in the radial direction. A gear product having gear teeth on the outer peripheral portion is formed by plastically flowing outward and filling the outer peripheral portion into the gear teeth of the gear forming die.

(Problems to be Solved by the Invention) In the above-described conventional method for manufacturing a gear forming die, since the metal structure is divided to form gear teeth, the strength of the tooth portion is reduced, and the machined surface due to electric discharge machining is reduced. There was a drawback that accuracy became difficult to obtain due to the roughness of the.

In addition, the conventional gear forming method for gear products is
Since the material is made to plastically flow outward in the radial direction and the gear teeth are formed on the outer peripheral part only by the pressure due to this one-way plastic flow, the tooth part cannot be formed with high precision due to the molding pressure difference inside the product. However, it is an object of the present invention to obtain a novel method for manufacturing a gear forming die for forging and a method for forming a gear product by the gear forming die, which solves the above-mentioned drawbacks.

(Means for Solving the Problems) The present invention is configured as follows to achieve the above object.

That is, a cylindrical intermediate material whose outer peripheral surface is tapered downward and has a hole formed in its axial center is provided, and this intermediate material is taper-fitted into the die hole at its outer peripheral surface. After sliding the intermediate material downward in the die hole,
The master gear having gear teeth formed on the outer periphery is pushed into the axial center of the intermediate material from above.

In addition, a cylindrical intermediate material having an outer peripheral surface that is tapered downward and having a hole formed in its axial center is provided, and the intermediate material is tapered to the first die hole on the outer peripheral surface. After fitting and sliding the intermediate material downward in the first die hole, the first master gear having gear teeth formed on the outer peripheral portion is pushed into the axial center portion of the intermediate material from above to the inner periphery. An intermediate gear forming die having gear teeth is provided, the outer peripheral surface of the intermediate gear forming die is taper-fitted into a second die hole, and a second master gear having gear teeth formed on the outer peripheral portion is provided from above. The intermediate gear forming die is press-fitted into the gear teeth, and the intermediate gear forming die is slid downward in the second die hole to be radially compressed.

Further, a tubular I-shaped gear forming die having gear teeth formed on the inner peripheral portion is fitted into the hole of the form frame, and a disk-shaped intermediate product is fitted into the I-th gear forming die. The intermediate product is bulged to a large diameter by axial compression and the outer peripheral portion is filled in the gear teeth of the I-th gear forming die to form an intermediate gear forming having gear teeth on the outer peripheral portion. Forming a mold,
The outer peripheral surface is formed in a tapered shape that shrinks downward,
And, the cylindrical second gear forming die having gear teeth formed in the inner core is taper-fitted to the vertical middle part of the hole of the form,
The lower end of the intermediate gear product is meshed with the upper end of the gear forming die of No. 1, the intermediate gear product is slid downward in the second gear forming die, and the second gear forming die is formed into a frame. It is configured such that the intermediate gear product is slid downward in the hole and then the intermediate gear product is axially compressed.

(Operation) Since the present invention has the above-mentioned configuration, the intermediate material is
Gear teeth are formed on the inner peripheral portion of the die hole by the radially inward pressurization and the master gear radially outward pressurization.

Further, in the intermediate gear forming die, the gear teeth are finished and formed on the inner peripheral portion thereof by the pressing force inward in the radial direction by the second die hole.

Further, the gear product has an outer periphery due to a two-way force consisting of a radially inward pressing force of the second gear forming die and a radially outward plastic flow of the intermediate gear product due to axial compression. Gear teeth are formed in the portion.

(Examples) Examples of the present invention will be described below with reference to the drawings.

In the drawings, FIGS. 1 to 4 are sectional views of steps 1 to 4 showing a method of manufacturing an I-th gear forming mold according to the present invention, and FIGS. 5 to 8 are sectional views of the present invention II. Sectional drawing of the 1st process-4th process which shows the manufacturing method of a gear mold, FIG. 9-
FIG. 12 is a cross-sectional view of steps 1 to 4 showing the method for molding a gear product by the gear molding die of the present invention.

First, a method of manufacturing the I-th gear mold will be described.

In FIG. 1, reference numeral 1 denotes a metal intermediate material formed by turning, in which a hole 2 at an axial center portion is formed to have an equal diameter and an outer peripheral surface 3 is formed to be a tapered surface having a smaller diameter on the lower side. The outer peripheral surface 3 is formed as a stepped taper surface having a step portion 4 at an intermediate portion in the vertical direction.

The intermediate material 1 is taper fitted on the outer peripheral surface 3 thereof into the first die hole 11 formed in the first die 10.

The first die hole 11 is formed in a tapered surface having a smaller diameter on the lower side, and has a length in the up-down direction longer than the width in the up-down direction of the intermediate material 1, and an intermediate material in the up-down direction intermediate portion. 1 is fitted and held. Further, the first die 10 is supported on the machine base by a base 12, and the base 12 has a pin hole 13 having a diameter slightly larger than the hole 2 of the intermediate material 1 at the axial center thereof.

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

Reference numeral 17 denotes a cylindrical guide fitted and locked on the upper part of the first die hole 11 to guide the first master gear 15 and regulate the lowermost moving position of the ram to lower the first master gear 15 to the lowest position. Determine the 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 the lower end thereof is fitted to the upper portion of the pin hole 13 of the base 12.

In this state, as shown in FIG. 2, the first master gear 15 is lowered through the ram and pushed into the axial center portion of the intermediate material 1,
While pushing the gear teeth 16 of the first master gear 15 into the hole 2 of the intermediate material 1, the intermediate material 1 is pushed into the first die hole by the pushing force.
When the lower end of the first master gear 15 is positioned at the intermediate portion of the hole 2 in the vertical direction, the ram is brought into contact with the guide 17 so that the first ram is brought into contact with the upper surface of the base 12. 1 Stop the lowering of the master gear 15.

By the way, the above-mentioned intermediate material 1 is subjected to a two-way force consisting of a radially inward pressing force by the first die hole 11 and a radially outward pressure by the gear teeth 16 of the first master gear 15. Gear teeth 6 are formed on the inner peripheral portion of the upper half portion, and an intermediate gear molding die 5 having the gear teeth 6 is formed.

The stopper 18 is moved from the hole 2 to the pin hole 13 by the lowering of the first master gear 15, and restricts the movement of the intermediate material 1 in the axial direction of the gear when the gear teeth are formed by the first master gear 15. It is for.

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

The second die hole 21 is similar to the first die hole 11 described above,
The lower part is formed into a taper surface having a small diameter, and the intermediate gear molding die 5 is fitted and held under the second die hole 21.

The second die 20 is supported on a machine base by a base 22, and the base 22 has a recessed portion 23 at the axial center thereof, into which the lower portion of the intermediate gear molding die 5 can be fitted.

Further, the second master gear 25 has high-precision gear teeth 26 formed on the outer peripheral portion thereof in the same manner as the above-mentioned first master gear 15, and the gear teeth 26 are formed on the intermediate gear forming die 5 as described above.
It press-fits and meshes with the gear tooth 6 of.

Reference numeral 27 denotes a guide, which is fitted in the upper portion of the second die hole 21 so that its lower end abuts on the upper surface of the intermediate gear molding die 5, and its upper end projects above the upper end of the second master gear 25.
Further, the large-diameter step portion 27-1 formed on the outer periphery is separated from the upper surface of the second die 20 by a predetermined amount.

Then, as shown in FIG. 4, the guide 27 is lowered via the ram, and the intermediate gear forming die 5 is slid downward along the second die hole 21, so that the second master gear 25 and the second die hole are moved. The intermediate gear forming die 5 is compressed in the radial direction by 21 to form the I-th gear forming die 8 having the finished gear teeth 9 on the inner peripheral portion.

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

In FIG. 5, reference numeral 1a is a metal intermediate material formed by turning, the hole 2a of the shaft center portion is formed to have the same diameter, and the outer peripheral surface 3a is formed to a tapered surface having a smaller diameter on the lower side.

The outer peripheral surface 3a of the intermediate material 1a is taper-fitted to the intermediate portion in the vertical direction of the first die hole 11a formed in the first die 10a.

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

15a is a first master gear that is pressed downward by the ram, and the first master gear 15a has gear teeth 1 on its outer peripheral portion.
6a, and a cylindrical plug portion 18a is integrally provided under the gear teeth 16a.

The gear teeth 16a are cut and formed by a gear cutting machine, and then heat-treated and ground to be finished with high precision.

Reference numeral 17a denotes a cylindrical guide, which is fitted and locked at the upper end portion of the first die hole 11a to guide the first master gear 15a and regulates the lowest moving position of the ram so as to control the first master gear.
Determine the lowest position of 15a.

When processing the intermediate material 1a, as shown in FIG. 6, the first master gear 15a is lowered via the ram, and first the intermediate material 1a is slid downward along the first die hole 11a. And contact the upper surface of the base 12a, and in this state the first
By pushing the gear tooth 16a of the master gear 15a into the hole 2a of the intermediate material 1a, when the lower end of the gear tooth 16a is located at the lower end of the hole 2a, by restricting the downward movement of the ram by the upper end of the guide 17a, The lowering of the first master gear 15a is stopped.

By the way, the above-mentioned intermediate material 1a has the pressing force inward in the radial direction by the first die hole 11a and the gear teeth 1 of the first master gear 15a.
A gear tooth 6a is formed on the inner peripheral portion that leaves the lower end portion by a force in two directions consisting of a pressure outwardly in the radial direction by 6a, and an intermediate gear molding die 5a having the gear tooth 6a is formed.

The plug portion 18a is for controlling the movement of the intermediate material 1a in the axial direction when the gear teeth are formed by the first master gear 15.

Next, after removing the lower end portion of the intermediate gear forming die 5a, as shown in FIG. 7, the gear teeth 6a are press-fitted into the gear teeth 26a of the second master gear, which will be described later, to form a tapered shape on the second die 20a. The second die hole 21a is fitted and locked at an intermediate portion in the vertical direction.

The second die 20a is supported on the machine base by a base 22a, and has the same pin hole 23a as the base 12a.

Further, the second master gear 25a has high-precision gear teeth 26a formed on the outer peripheral portion thereof in the same manner as the first master gear 15a described above, and a cylindrical plug portion 28a is integrally provided under the gear teeth 16a. Then, the gear tooth 26a is press-fitted into the gear tooth 6a of the intermediate gear molding die 5a as described above.

Reference numeral 27a denotes a guide, which is fitted to the upper portion of the second die hole 21a so that its lower end abuts on the upper surface of the intermediate gear molding die 5a and its upper end is at the same level as the upper end of the second master gear 25a.
The step portion 27a-1 having the diameter formed on the outer periphery thereof is separated from the upper surface of the second die 20a by a predetermined amount.

Then, as shown in FIG. 8, the second master gear 25a and the guide 27a are lowered through the ram until the step portion 27a-1 of the guide 27a comes into contact with the upper surface of the second die 20 to form the intermediate gear. The mold 5a is slid downward along the second die hole 21a.

As a result, the intermediate gear forming die 5a is radially compressed by the second master gear 25a and the second die hole 21a to form the second gear forming die 8a having the finished gear teeth 9a on the inner peripheral portion. .

Next, a method of processing a gear product by the above-mentioned I and II gear forming dies 8 and 8a will be described.

First, the intermediate gear product 41 is processed by the I-th gear molding die 8.

In FIG. 9, 30 is a form supported by a base 34, and has a hole 31 at the axial center.

The deposit 32 and the above-described I-th gear forming die 8 are press-fitted into the lower portion and the upper portion of the hole 31, and the first lower die 33 is press-fitted into the lower portion of the gear forming die 8. In this case, the outer periphery of the I-th gear molding die 8 is cut into a stepped shape having a small diameter at the upper portion and a large diameter at the lower portion, and is press-fitted and locked in the hole 31 of the mold frame 30.

Next, the disc-shaped forged intermediate product 40 is fitted into the I-th gear forming die 8 and placed on the I-th lower die 33.

35 is a first punch supported by a ram (not shown),
The first punch 35 includes a cylindrical outer peripheral punch 36 having gear teeth on the outer peripheral portion and a shaft-shaped central punch 37 positioned at the axial center portion thereof.
Consists of.

Then, as shown in FIG. 10, the first punch through the ram.
35 is lowered and pushed into the axial center portion of the intermediate product 40, and 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 so that the outer peripheral portion is radially outward. Plastic flow in one direction to fill the outer peripheral portion into the gear teeth 9 of the I-th gear forming die 8 to form an intermediate gear product 41 having gear teeth 42 on the outer peripheral portion.

In FIG. 9 and FIG. 10, 38 is an extruding rod for extruding the formed intermediate gear product 41 upward from the I-th gear forming die 8.

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

In FIG. 11, reference numeral 30a is a mold supported by a base 34a, and has a tapered hole 31a having a small diameter in the lower part in the axial center part.

The cylindrical second lower die 33a is taper-fitted to the lower portion of the hole 31a, and the above-mentioned II gear forming die 8 is provided on the upper portion of the hole 31a.
The a is taper-fitted by slightly separating it from the second lower mold 33a.

Next, the above-mentioned intermediate gear product 41 is turned upside down to
Engage with the upper end of the gear molding die 8a of II.

Reference numeral 35a denotes a cylindrical second punch supported by a ram (not shown). The second punch 35a has a large diameter outer peripheral punch 36a which is in contact with the upper surface of the second gear molding die 8a at its lower portion. The intermediate gear product 41 is projected below the outer peripheral punch 36a.
And a central punch 37a having a small diameter that abuts on the upper surface of the.

Then, as shown in FIG. 12, the second punch is made through the ram.
35a is lowered and first the intermediate punch 37a
41 is moved downward in the second gear forming die 8a, and then the outer peripheral punch 36a is used to move the second gear forming die 8a into the hole of the form frame 30a.
After sliding downward in 31a to compress the gear teeth 9a in the axial direction, the outer peripheral portion of the intermediate gear product 41 is axially moved by the central punch 37a and the second lower die 33a at the lowest position. Direction to compress this part to plastically flow outward in the radial direction.

As a result, the gear teeth 42 of the intermediate gear product 41 are subjected to a bidirectional force by the axial pressurization by the gear teeth 9a of the second gear molding die 8a and the radial outward plastic flow pressure. Thus, the gear product 44, which is a product, is finished with high precision.

Note that in FIG. 11 and FIG. 12, 38a is a push rod that pushes the molded gear product 44 upward from the II gear molding die 8a.

(Effects of the Invention) As is apparent from the above description, according to the present invention, the inner peripheral portion of the intermediate material is compressed and plastically flowed in two directions, that is, the outer side and the inner side in the radial direction, so that the inner peripheral portion of the master gear tooth is formed. Therefore, it is possible to obtain a gear forming mold having teeth with high strength and high precision.

In addition, since the intermediate gear forming die formed as described above is compressed from the outside in the radial direction to press the gear teeth of the inner peripheral portion thereof to the gear teeth of the second master gear, It is possible to obtain a gear molding die having highly accurate and highly accurate teeth.

In addition, the intermediate gear product having gear teeth on the outer periphery is engaged with the gear teeth of the gear forming die, and the intermediate gear product is compressed in the axial direction by the gear forming die.In this state, the intermediate gear product is compressed in the axial direction. Since the outer peripheral portion of the intermediate gear product is plastically flowed outward in the radial direction, the gear tooth portion of the intermediate gear product is compressed in two directions, the outer side and the inner side in the radial direction. Further, it is possible to obtain a gear product having highly accurate teeth.

[Brief description of drawings]

1 to 4 are sectional views of 1st to 4th steps showing a method for manufacturing an I-th gear molding die according to the present invention, and 5 to 8
The drawings are sectional views of the first to fourth steps showing the method for manufacturing the second gear molding die according to the present invention, and FIGS. 9 to 12 are drawings showing the method for molding a gear product by the gear molding die according to the present invention. It is sectional drawing of 1st process-4th process. 1,1a: intermediate material, 2,2a: hole, 3,3a: outer peripheral surface, 4: step, 5,5a:
Intermediate gear forming die, 6,6a: Gear tooth, 7,7a: Outer peripheral surface, 8,8a: No. I, No. II gear forming die, 9, 9a: Gear tooth. 10,10a ,: First die, 11,11a: First die hole, 12,12a: Base, 13,13a ,: Pin hole, 15,15a: First master gear, 16,16a:
Gear teeth, 17, 17a: guide, 18: stopper, 18a: stopper. 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: guide, 27-1, 27a-1: step, 28a:
Stopper part. 30,30a: Form, 31,31a: Hole, 32: Deposit, 33,33a: First and second lower molds, 34,34a: Base, 35,35a: First and second punches, 36,36a:
Peripheral punch, 37, 37a: Central punch, 38, 38a: Extruded rod. 40: Intermediate product, 41: Intermediate gear product, 42: Gear teeth, 44: Gear product.

Claims (3)

[Claims] 1. A cylindrical intermediate material having an outer peripheral surface formed in a taper shape that shrinks downward and having a hole formed in a shaft center portion, and the intermediate material is formed into a die hole on the outer peripheral surface. Forging characterized by taper-fitting, sliding the intermediate material downward in the die hole, and then pushing a master gear having gear teeth formed on the outer peripheral portion into the shaft center portion of the intermediate material from above. For manufacturing gear molding dies for automobiles. 2. A cylindrical intermediate material having an outer peripheral surface formed in a taper shape that shrinks downward and having a hole formed in an axial center portion, the intermediate material being provided on the outer peripheral surface of the first die. After taper-fitting into the hole and sliding the intermediate material downward in the first die hole, the first master gear having gear teeth formed on the outer peripheral portion is pushed into the shaft center portion of the intermediate material from above. An intermediate gear molding die having gear teeth formed on the inner circumference is provided, and the intermediate gear molding die is taper fitted to the second die hole on the outer peripheral surface thereof.
A second master gear having gear teeth formed on the outer periphery is press-fitted into the gear teeth of the intermediate gear forming die from above, and the intermediate gear forming die is slid downward in the second die hole in the radial direction. A method for manufacturing a forging gear forming die, which is characterized by being compressed. 3. A cylindrical I-shaped gear forming die having gear teeth formed on an inner peripheral portion thereof is fitted into a hole of a form, and a disk-shaped intermediate formed in the I-th gear forming die. A gear tooth is provided on the outer peripheral portion by fitting the product, bulging the intermediate product into a large diameter by axial compression, and filling the outer peripheral portion into the gear tooth of the I-th gear forming mold. An intermediate gear product is formed, and the lower die is fitted to the lower part of the mold frame hole where the inner peripheral surface shrinks downward, and the outer peripheral surface is tapered so as to contract downward, The cylindrical second gear forming die having gear teeth is separated from the lower die upward and is fitted into the upper part of the hole of the formwork by a taper, and the intermediate gear is attached to the upper end of the second gear forming die. The lower end of the product is engaged and the punch that descends slides the intermediate gear product downward in the second gear mold. In both cases, the second gear forming die is slid downward in the hole of the form, and then the intermediate gear product is axially compressed by the punch and the lower die. Product molding method.