JP2003080338A - Manufacturing method of die for crowning gear, and crowing gear manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily form a die for a crowning gear, and to forge the crowning gear by using this die. SOLUTION: A primary die (41) with internal teeth (41a) formed in a substantially equal gear thickness over the entire length is provided, a crown tooth electrode (16) with a side surface of external teeth (16a) formed in a crown is provided, each tooth (16a) of the crown tooth electrode (16) is fitted between the teeth (41a) of the primary die (41) with the primary die (41) elastically deformed to a small diameter, the crown tooth electrode (16) is reciprocally turned in the circumferential direction at the predetermined angle while energizing the crown tooth electrode (16, each tooth (41a) of the primary die (41) is electric-discharge machined so that profile of the tooth (41a) corresponds to the profile of the teeth (16a) of the crown tooth electrode (16), and a finishing die (42) is provided for finishing the profile of the internal teeth (42a) to form a counter-crown shape.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a die for forging a crowning gear in which the tooth thickness of external teeth gradually increases from both ends in the longitudinal direction toward the center, and a method for manufacturing the crowning gear. .

[0002]

2. Description of the Related Art When molding a crowning gear by forging, it is necessary to make the inner teeth of a die anti-crown teeth whose tooth thickness gradually decreases from both ends in the longitudinal direction toward the center. However, conventionally, it has been difficult to process the inner teeth into anti-crown teeth, so the teeth of the roughly processed gear (external gear) are ground by a gear grinder or the like to obtain a crowning gear.

[0003]

The above-mentioned conventional ones have poor productivity and require skill in processing. An object of the present invention is to obtain a method for manufacturing a die capable of forming a crowning gear by forging with high productivity and a method for producing a crowning gear by the die.

[0004]

The present invention is configured as follows to achieve the above object. That is, the invention according to claim 1 provides a primary mold in which inner teeth are formed to have a substantially uniform tooth thickness over the entire length, and a crown tooth electrode in which side surfaces of outer teeth are formed in a crown shape is provided. Each tooth of the crown tooth electrode is fitted between each tooth of the primary die while the die is elastically deformed to a small diameter, and the crown tooth electrode is encircled at a predetermined angle while energizing the crown tooth electrode. Direction and reciprocally rotate the teeth of the primary mold to perform electric discharge machining so that the side surface shape corresponds to the side surface shape of the tooth of the crown tooth electrode, and thus the finishing metal mold in which the side surface of the inner tooth has an anti-crown shape. It is configured to have a mold. According to a second aspect of the present invention, each tooth of the primary mold is a helical tooth, and each tooth of the crown tooth electrode is a helical crown tooth fitted between the helical teeth. According to a third aspect of the present invention, the finishing die according to the first aspect and a primary gear in which outer teeth are formed to have substantially equal tooth thickness over the entire length are provided, and each tooth of the primary gear is the finishing die. The teeth of the primary gear are pressed into contact with the teeth of the primary gear, and the side surfaces of the teeth of the primary gear are formed into a crown shape. It is configured to do. In the invention according to claim 4, each tooth of the primary gear is a helical tooth, and each tooth of the finishing die is a helical anti-crown tooth with which each helical tooth of the primary gear is fitted.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. 1 is a sectional view showing a processed state of a primary mold according to the present invention, FIG. 2 is a sectional view for explaining a tooth portion of FIG. 1, FIG. 3 is a sectional view for explaining a tooth portion of a primary mold, and FIG. 4 is a book. FIG. 5 is a sectional view showing a working state of the finishing die according to the invention, FIG. 5 is an explanatory sectional view of the tooth portion of FIG. 4, and FIG. 6 is an enlarged sectional view taken along line VI-VI of FIG.
FIG. 7 is a sectional view showing a processed state of the primary gear according to the present invention,
8 is a sectional view showing a machining state of the crowning gear according to the present invention, FIG. 9 is a sectional view for explaining a state before machining the tooth portion according to FIG. 8, and FIG. 10 is an explanation showing a machining state of the tooth portion according to FIG. FIG.

In FIG. 1, reference numeral 1 is a first electric discharge machine for molding a primary mold 41, and a holding device 2 for holding a ring-shaped mold material 40 and helical teeth on the inner circumference of the held mold material 40. It has the coarse tooth electrode 10 which forms 41a. The holding device 2 is as follows. That is, the cylindrical clamp 4 and the pressure receiving plate 5 are vertically arranged and press-fitted and fixed in the center of the outer case 3 supported on the base side. The fitting hole 4a formed in the axial center portion of the clamp 4 is a tapered hole whose inner diameter gradually decreases from the upper part to the lower part, and the cylindrical mold material 40 is taper-fitted into the fitting hole 4a. .

A pressure device 6 is provided on the upper side of the outer case 3.
To provide. The pressurizing device 6 has a ring-shaped holder 8 and a pressurizing ring 9 which are sequentially attached to the lower part of a vertically moving punch 7 so as to be downwardly stacked. Protrusions 9a are formed, and when the punch 7 moves downward, the protrusions 9a press the die material 40 downward, so that the die material 40 is engaged with the clasp 4 with a predetermined frictional force.

The above-mentioned coarse tooth electrode 10 is a helical tooth 10 in which the tooth thickness is equal over the entire length on the outer circumference of the cylindrical electrode body.
a is formed, and the coarse tooth electrode 10 is the punch 7 described above.
It is suspended and supported by a holder 11 arranged at the axial center part of the holder 11, and is rotatably reciprocated in the vertical direction through the holder 11 at an angle equal to the twist angle of the helical teeth 10a, and is moved downward. Then, while the coarse tooth electrode 10 is energized, the coarse tooth electrode 10 is swung back and forth through the holder 11 as shown in FIG. The inner circumference of the material 40 is subjected to electric discharge machining to obtain a primary mold 41 having helical teeth 41a on the inner circumference as shown in FIG. The helical teeth 41a of the primary die 41 may be formed by a hobbing machine.

In FIG. 4, reference numeral 15 is a second electric discharge machine for molding the finishing die 42, and the holding device 2 for holding the above-mentioned primary die 41 and the primary die 41 held by the holding device 2. The helical crown tooth electrode 16 which forms the helical tooth 41a of the above into the helical anti-crown tooth 42a. The holding device 2 has substantially the same structure as described above. That is, the cylindrical clamp 4 and the pressure receiving plate 5 are vertically arranged and press-fitted and fixed in the center of the outer case 3 supported on the base side, and the fitting hole 4a of the clamp 4 has an inner diameter from the upper part to the lower part. The taper hole gradually shrinks toward the front side, and the above-mentioned primary mold 41 is taper-fitted into the fitting hole 4a.

In the pressure device 6 provided on the upper side of the outer case 3, a ring-shaped holder 8 and a pressure ring 9-1 are attached to the lower part of a vertically moved punch 7 so as to be sequentially stacked downward. The pressure ring 9-1 has a ring-shaped protrusion 9-1a protruding downward at the lower portion of the inner circumference thereof. The amount of downward projection of the protrusion 9-1a is determined by the pressure ring 9 described above.
When the punch 7 moves downward, the primary mold 41 taper-fitted to the clamp 4 by the projection 9a is pushed downward by a predetermined amount to move the punch 7a.
1 is elastically deformed to a small diameter.

The above-mentioned helical crown tooth electrode 16 is formed by forming helical crown teeth 16a at a predetermined pitch on the outer circumference of a cylindrical electrode body. This helical crown tooth 16
a has the same twist angle as the helical teeth 41a of the primary mold 41 described above, and its side surface shape is a crown shape having the same shape as the side surface shape of the target helical crowning gear teeth. The helical crown teeth 16a have a pitch and a tooth thickness that are loosely fitted between the helical teeth 41a of the primary die 41.

The helical crown tooth electrode 16 is suspended and supported by the holder 11 arranged at the axial center portion of the punch 7 described above, and the crown tooth electrode 16a is circulated through the holder 11 at a predetermined angle in the circumferential direction, in this example, a circle. 0.01mm in the circumferential direction
It is designed to be reciprocally rotated at an angle of 0.02 mm. Then, as shown in FIG. 4, the helical crown tooth electrode 16 is fitted to the axial center portion of the primary die 41 held by the holding device 2 so that each helical crown tooth 16 a is attached to each helical die of the primary die 41. The teeth 41a are meshed with each other, and the helical crown tooth electrode 16 is energized in this state, and the helical crown tooth electrode 16 is passed through the holder 11 in the circumferential direction from 0.01 mm to 0 mm as shown in FIGS. 0.02 mm
By reciprocally rotating (arrow B) at an angle of, the helical teeth 41a of the primary mold 41 are subjected to electric discharge machining, and the side surface shape of each tooth corresponds to the side surface shape of the tooth 16a of the helical crown tooth electrode 16. The finishing die 42 that becomes the anti-crown teeth (inner teeth) 42a is obtained.

In FIG. 7, 20 is the primary helical gear 4.
6, which is an extrusion molding machine, has a cylindrical container 21 that forms helical teeth on the outer periphery of the contained material 45, and a punch 27 that pushes out the material 45 in the container 21 downward. The container 21 has helical shaped teeth 21a projecting in the axial direction on the inner circumference of the lower part thereof. The forming tooth 21a has a tooth thickness and a tooth height which gradually increase from the upper side to the lower side, and the outer periphery of the forming tooth 21a is clamped by a clamp 22.
Is mounted on the pressure receiving plate 23 by being surrounded by, and both are connected by the outer case 24 so as to be rotatably attached to the pedestal 25.

A shaft-shaped mandrel 26 is fitted to the shaft center of the container 21 with a predetermined gap, and is rotatably supported on the base side. The mandrel 26 is fitted in the central portion of the cylindrical material 45, and the diameter of the mandrel 26 is changed to adjust the cross-section reduction rate of the material 45.

The punch 27 has a cylindrical shape that fits between the container 21 and the mandrel 26, and is rotatably supported by the ram (not shown). Then, a plurality of materials 45 are vertically stacked and fitted between the container 21 and the mandrel 26, and the materials 45 are moved downward by the punch 27 to pass through the molding teeth 21a of the container 21. As a result, as shown by the phantom line in FIG. 7, the primary helical gear 46 having the helical teeth 46a with the same tooth thickness over the entire length on the outer circumference is obtained.

Next, each helical tooth 46a of the primary helical gear 46 is formed into a helical crown tooth 47a by the finishing die 30 shown in FIG. Finishing die 30 above
Is the inner case 3 on the upper side of the pressure receiving plate 31.
3, and a cylindrical die case 32 reinforced by the outer case 34 is attached, and a clamp 39 vertically moved by a punch 38 is slidably fitted in the die case 32. The clamp 39 has a tapered hole 39a having a large diameter on the lower side in the axial center thereof, and the finish die 42 described above can be fitted into the tapered hole 39a by taper fitting.

The diameter of the taper hole 39a of the clamp 39 is made slightly smaller than the taper surface of the outer periphery of the finishing die 42, as shown in FIG.
As shown by the phantom line in FIG.
The two tapered surfaces are brought into close contact with each other at a point slightly above the lower end of 2. A cylindrical stopper die 36 for receiving the finishing die 42 is arranged at the axial center portion of the pressure receiving plate 31 and is erected and fixed to the base side, and a shaft erected and supported at the base side of the axial center portion of the clamp 39. Shaped core metal 37
Are fitted while holding a predetermined gap.

Then, the above-mentioned primary helical gear 46 is fitted in the finishing die 42, and the respective helical teeth 46a thereof are fitted between the helical anti-crown teeth 42a of the finishing die 42 in this state. The primary helical gear 46 is inserted through the cored bar 37 and fitted into the die case 32 together with the finishing die 42, and the lower surface of the finishing die 42 is brought into contact with the upper surface of the stopper die 36.

In this state, as shown by the solid line in FIG. 8, the clasp 39 is lowered through the punch 38 to the position where the lower surface of the clasp 39 contacts the upper surface of the stopper die 36, and the taper hole 39a of the clasp 39 is used. The finish die 42 is elastically deformed into a small diameter. As a result, each helical anti-crown tooth 42a of the finishing die 42 changes from the state of the pitch shown in FIG. 9 to a small pitch and a small diameter as shown in FIG. 10, and the helical anti-crown tooth 42a of the primary helical gear 46 changes. The teeth 46a are pressed into contact with each other to plastically deform the teeth 46a into helical crown teeth 47a whose tooth thickness gradually increases from the upper and lower ends toward the center, and as shown in FIG. 10, a desired product, that is, a helical crowning gear 47 is formed. Can be obtained.

When the punch 38 is moved upward after the helical crowning gear 47 is formed, the clamp 39 is moved upward and the finishing die 42 elastically returns to a large diameter, so that the internal helical crowning gear 47 is moved. You can take it out.
In the present invention, the crowning gear whose teeth extend linearly in the axial direction can also be formed by forging. in this case,
The helical tooth 10a of the coarse tooth electrode 10 of the primary electric discharge machine 1 described above is a flat tooth extending in the axial direction, the helical crown tooth 16a of the crown tooth electrode of the second electric discharge machine 16 is a crown tooth extending in the axial direction, and The molding teeth 21a of the container 21 of the extrusion molding machine 15 need to be changed to flat teeth molding teeth extending in the axial direction.

[0021]

As is apparent from the above description, the invention according to claim 1 of the present invention elastically deforms a primary mold in which inner teeth are formed to have a substantially equal tooth thickness over the entire length into a small diameter, A crown tooth electrode whose outer teeth have side faces formed in a crown shape is fitted in the primary die, and the crown tooth electrode is reciprocally rotated in the circumferential direction at a predetermined angle to crown the side face shape of each tooth of the primary die. Since the electric discharge machining is performed so as to correspond to the side surface shape of the tooth of the tooth electrode, the crown tooth electrode can be axially pulled out from the machined product by elastically returning the primary die after the electric discharge machining. It is possible to easily manufacture a finishing die in which the side surfaces of the teeth have an anti-crown shape. In the invention according to claim 2, since each tooth of the primary mold is a helical tooth and each tooth of the crown tooth electrode is a helical anti-crown tooth fitted between the helical teeth, the side surface of the inner tooth is A finishing die having a helical anti-crown shape can be easily manufactured.
According to a third aspect of the present invention, the finish die according to the first aspect is fitted to a primary gear in which the outer teeth are formed with a substantially equal tooth thickness over the entire length, and in this state, the finish die is elastically reduced in diameter. Since each tooth is deformed and pressed against each tooth of the primary gear to form the side surface of each tooth of the primary gear in a crown shape,
By elastically returning the primary mold, the product can be axially removed from the finish mold, and the crowning gear can be easily manufactured by forging. In the invention according to claim 4, since each tooth of the primary gear is a helical tooth and each tooth of the finishing die is a helical anti-crown tooth with which each helical tooth of the primary gear is fitted, the helical crowning gear is It can be easily manufactured by forging.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a processed state of a primary mold according to the present invention.

FIG. 2 is a sectional view for explaining a tooth portion of FIG.

FIG. 3 is an explanatory cross-sectional view of a tooth portion of a primary mold.

FIG. 4 is a cross-sectional view showing a processed state of a finishing die according to the present invention.

5 is a cross-sectional view for explaining the tooth portion of FIG.

6 is an enlarged sectional view taken along line VI-VI of FIG.

FIG. 7 is a cross-sectional view showing a processed state of the primary gear according to the present invention.

FIG. 8 is a cross-sectional view showing a processed state of the crowning gear according to the present invention.

9 is an explanatory sectional view showing a state before processing the tooth portion according to FIG. 8;

10 is an explanatory cross-sectional view showing a processed state of a tooth portion according to FIG.

[Explanation of symbols]

1 Primary electrical discharge machine 2 holding device 3 outer case 4 tightening 4a Fitting hole 5 Pressure plate 6 Pressurizing device 7 punches 8 holder 9 (9-1) Pressure ring 9a (9-1a) protrusion 10 coarse tooth electrode 10a helical teeth 15 Second electric discharge machine 16 Crown tooth electrode 16a Helical crown tooth (external tooth) 20 Extruder 21 container 22 Clamp 23 Outer case 24 Pressure plate 25 cradle 26 Mandrel 27 punch 30 finishing mold 31 Pressure plate 32 die case 33 Inner case 34 outer case 35 tightening 36 Stopper die 37 core 38 punches 39 tightening 39a Tapered hole 40 mold material 41 Primary mold 41a Helical tooth (internal tooth) 42 Finishing die 42a Helical anti-crown tooth (internal tooth) 45 materials 46 Primary Helical Gear 46a Helical tooth (external tooth) 47 Helical crowning gear 47a helical crown tooth

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Shoichi Koyama             Fuji Co., Ltd. 2418 Washizu, Kosai City, Shizuoka Prefecture             In Univance (72) Inventor Yoshinori Sato             Fuji Co., Ltd. 2418 Washizu, Kosai City, Shizuoka Prefecture             In Univance F-term (reference) 3C059 AA01 AB01 HA09                 3J030 AC03 BA04 BA05 BC06                 4E087 AA10 CA11 ED01 HA02 HA04

Claims (4)

[Claims] 1. A crown tooth electrode in which a primary mold (41) having inner teeth (41a) formed to have a substantially equal tooth thickness over the entire length is provided, and side surfaces of outer teeth (16a) are formed in a crown shape. 16)
And each tooth (16a) of the crown tooth electrode (16) is fitted between each tooth (41a) of the primary die (41) while the primary die (41) is elastically deformed to a small diameter. Then, while energizing the crown tooth electrode (16), the crown tooth electrode (16) is reciprocally rotated in the circumferential direction at a predetermined angle to form each tooth (41a) of the primary mold (41) in its side surface shape. By electric discharge machining so that the shape corresponds to the side surface shape of the tooth (16a) of the crown tooth electrode (16).
A method of manufacturing a crowning gear mold, characterized in that a finishing mold (42) having an anti-crown side surface is provided. 2. Each tooth of the primary die (41) is replaced by a helical tooth (4).
1a), and each tooth of the crown tooth electrode (16) is a helical crown tooth (16) fitted between the helical teeth (41a). Method. 3. A finishing die (42) according to claim 1, and a primary gear (46) having external teeth (46a) formed to have a substantially equal tooth thickness over the entire length, and the primary gear (46). ) Each tooth (46a) is fitted between each tooth of the finishing die (42), and then the finishing die (42) is elastically deformed to a small diameter so that each tooth (42a) is moved to the primary gear (42a). The primary gear (4) is pressed against each tooth (46a) of
6) A method for manufacturing a crowning gear, characterized in that the side surface of each tooth (46a) is formed in a crown shape. 4. Each tooth of the primary gear (46) is replaced by a helical tooth (4).
6a), and each tooth of the finishing die (42) is a helical anti-crown tooth (42a) with which each helical tooth (46a) of the primary gear (46) is fitted. Crowning gear manufacturing method.