JPH10225743A - Cold forging die for tooth form parts - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cold forging die for tooth form parts, a die capable of obtaining high precision products while a high work efficiency is secured. SOLUTION: The die consists of a flat die 2 whose inner circumference is formed with a die face 2a corresponding to the outer tooth form, a breakout punch 6 and a projecting die 5 which are both situated above the flat die 2 and which are divided into two inner and outer pieces with a circle in contact with the outer tooth form as the boundary, with the breakout punch 6 arranged inside and the projecting die 5 outside. These flat die 2, projecting die 5 and the breakout punch 6 are so structured that, with a work W held between the flat die 2 and the projecting die 5, the projecting die 5 and the breakout punch 6 are lowered alike against the work W, so that cutting is performed with the flat die 2, and that the lower face of the breakout punch 6 is then projected from the lower face of the projecting die 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cold forging die for a tooth-shaped part for obtaining a tooth-shaped part such as a spline part having an external tooth shape from a work. This forging die can manufacture flat tooth-shaped parts such as spline parts with external teeth parallel to the axial direction, and bevel-shaped parts such as bevel spline parts along the helical winding of the external teeth.

[0002]

2. Description of the Related Art Conventionally, as shown in FIGS. 5 and 6, there has been known a cold forging die for manufacturing a flat tooth-shaped part having an external tooth shape parallel to an axial direction from a plate-shaped work W. In this forging die, a ring-shaped flat die 72 is fixed to the upper surface of a lower die holder 71, and a mold surface 72a parallel to the axial direction corresponding to the external tooth shape is formed on the inner periphery of the flat die 72. A substantially cylindrical ejector punch 73 is provided in the flat die 72 so as to be vertically movable. A flat tooth portion 73a meshing with a mold surface 72a of the flat die 72 is formed around the ejector punch 73. I have.

On the other hand, above the flat die 72, a ring-shaped projection die 75 is fixed to the lower surface of the upper die holder 74. The projection die 75 has a projection 75a projecting downward at the center of the lower end thereof, and a mold surface 75b parallel to the axial direction corresponding to the external tooth shape is formed on the inner periphery thereof. A substantially cylindrical breakout punch 76 is also provided in the projection die 75 so as to be able to move up and down, and a spur tooth portion 76 a meshing with the mold surface 75 b of the projection die 75 is also provided on the outer periphery of the lower end of the breakout punch 76. Is formed.
A similar forging die is disclosed in Japanese Utility Model Publication No. 1-40608.

When a spline part is manufactured by using this forging die, first, a flat die 72 and an ejector punch 7 are formed.
After the centering of the projection die 75 and the breakout punch 76 and the determination of the phase are performed, the workpiece W is placed on the horizontal upper surfaces of the flat die 72 and the ejector punch 73. Then, by operating a ram (not shown),
The projection die 75 and the breakout punch 76 are similarly lowered with respect to the work W, and the work W is
Is pressed against the flat die 72 at the end of the protrusion 75a and the end face of the breakout punch 76, and a cut is made at the flat die 72. At this time, the ejector punch 73 is pushed by the work W and descends.

Thereafter, the projection dies 7 are operated by the operation of the ram.
Immediately before the lower surface of the die 5 comes into contact with the upper surface of the flat die 72, the lowering of the projection die 75 is stopped, while the lowering of the breakout punch 76 and the ejector punch 73 is stopped at the center of the work W which is a product (flat spline part). Is continued. Then, the lowering of the breakout punch 76 and the ejector punch 73 is continued until the spur portion 76a of the breakout punch 76 engages with the mold surface 72a of the flat die 72. Part is divided.

After that, after the projection die 75 is raised while the breakout punch 76 is kept as it is, the ejector punch 73 is raised, so that the breakout punch 76 is also raised via the work W. Then, the product and the remaining portion of the blank are discharged from the flat die 72, and the breakout punch 76 is lifted to terminate the cold forging, and the product and the remaining portion of the blank are removed.

As shown in FIGS. 7 and 8, a forging die for manufacturing a bevel spline part having an external tooth shape along a helical winding from a plate-like work W is also known. In this forging die, a ring-shaped flat die 82 is fixed to the upper surface of a lower die holder 81, and a helical die surface 82a corresponding to the external tooth shape is formed on the inner periphery of the flat die 82. A substantially cylindrical ejector punch 83 is provided in the flat die 82 so as to be vertically movable and rotatable in a horizontal plane by a bearing 84. Bevel teeth 8 to mesh
3a are formed.

On the other hand, above the flat die 82, below the upper die holder 85, a ring-shaped guide member 88 is provided in a state of being urged downward via a plurality of detent pins 86 and compression springs 87. A beveled portion 88a having the same lead as the external toothed helical wire is formed on the inner periphery of the guide member 88. Each of the detent pins 86 penetrates the guide member 88, and the guide member 88 is regulated by a lower end step portion of each of the detent pins 86, and is lowered by respective spacers 89 fixed to the lower end. Has been positioned. A ring-shaped projection die 90 is provided in the guide member 88 so as to be rotatable in a horizontal plane by a bearing 91 on an upper die holder 85. The projecting die 90 has a beveled portion 90a meshed with the beveled portion 88a of the guide member 88 on its outer periphery, a downwardly projecting protruding portion 90b formed at the center of its lower end, and an outer periphery on its inner periphery. A helical mold surface 90c corresponding to the tooth shape is formed. A substantially cylindrical breakout punch 92 is also provided in the projection die 90 so as to be vertically movable and rotatable in a horizontal plane by a bearing 93. Face 90
A beveled portion 92a meshing with c is formed.

When a helical spline part is manufactured using this forging die, a flat die 82 and an ejector punch 83, a projecting die 90 and a breakout punch 92 are first used.
After the centering and phase determination are performed, the workpiece W is placed on the horizontal upper surfaces of the flat die 82 and the ejector punch 83. Then, by operating a ram (not shown),
The guide member 88, the projection die 90, and the breakout punch 92 are similarly lowered with respect to the work W, and the work W
Is cut by the projection 90b of the projection die 90. At this time,
The guide member 88 and the spacer 89 do not rotate. However, since the lower surface of the spacer 89 contacts the upper surface of the flat die 82 before the projection die 90 contacts the work W, the lowering of the guide member 88 stops. Further, since the projection die 90 meshing with the beveled tooth portion 88a of the guide member descends as the ram descends, the projection die 90 and the breakout punch 92 descend while rotating. Naturally, since the work W descends while rotating along the mold surface 82a of the flat die 82, the ejector punch 83 descends while being rotated by being pushed by the work W.

Thereafter, the lowering of the projecting die 90 is stopped immediately before the spacer 89 comes into contact with the upper surface of the flat die 82 and the lower surface of the projecting die 90 comes into contact with the upper surface of the flat die 82, while the breakout punch 92 and the ejector The lowering of the punch 83 is continued with the central portion of the workpiece W as a product held therebetween. Then, the breakout punch 92 and the ejector punch 83 until the beveled portion 92a of the breakout punch 92 meshes with the mold surface 82a of the flat die 82.
Is continued, the product is separated from the edge of the workpiece W, which is the remaining part of the punching.

Then, after the projection die 90 is raised while the breakout punch 92 is kept as it is, the ejector punch 83 is raised, so that the breakout punch 92 is also raised via the work W. Then, the product and the remaining portion of the blank are discharged from the flat die 82, and the breakout punch 92 is lifted to terminate the cold forging, and the product and the remaining portion of the blank are removed.

Further, as shown in FIGS. 9 and 10, there is also known a conventional die for manufacturing a spline component having an external tooth shape parallel to the axial direction from a plate-like work W. In this punching die, a punching hole 94a having a circular cross section and having a chamfer at the upper end edge is formed so as to circumscribe the die 94 in an external tooth shape. On the other hand, a guide member 95a having a circular cross-section and circumscribing the external tooth shape at the bottom is formed vertically through the holding member 95 located above the die 94, and a projection 95b projecting downward is formed at the center of the lower end. ing. A substantially cylindrical punch 96 is provided in the holding member 95 so as to be vertically movable, and a mold surface 96a parallel to the axial direction corresponding to the external tooth shape is formed on the outer periphery of the lower end of the punch 96.
A similar die is also disclosed in JP-A-6-122028.

When manufacturing a spline spline part using this die, first, only the centering of the die 94, the pressing member 95 and the punch 96 is performed, and the work W is placed on the horizontal upper surface of the die 94. Then, the pressing member 95 and the punch 96 are lowered with respect to the work W by operating a ram (not shown). As a result, the center of the workpiece W, which is a product, is separated from the edge of the workpiece W, which is the remaining part to be punched, and the conventional blanking is completed, and the workpiece W, which is a product, is finished.
And the edge of the workpiece W, which is the remaining part of the blank, can be taken out.

[0014]

However, in the two forging dies shown in FIGS. 5 to 8, in order to obtain a product, the teeth of the breakout punches 76 and 92 are formed on the mold surfaces 72 a and 82 a of the flat dies 72 and 82. Since the breakout punches 76 and 92 continue descending until the portions 76a and 92a engage with each other, it is necessary to determine the phase between the flat dies 72 and 82 and the breakout punches 76 and 92. In particular, these must be performed accurately taking into account the mold life due to non-meshing interference. Also, in the forging die for manufacturing the helical spline parts shown in FIGS.
The phase must be determined so that the helical winding of the second mold surface 82a, the helical winding of the beveled portion 90a of the projection die 90, and the helical winding of the beveled portion 92a of the breakout punch 92 are continuous. No. Therefore, it is easy to take time and effort to determine such a troublesome phase, and it is easy to impair the work efficiency.

Further, in the punching die shown in FIGS. 9 and 10,
In order to obtain the product, it is sufficient to perform only centering, and there is no trouble in determining the phase.On the other hand, except for the surface with the tip circle as the generating line among the tooth top surfaces in the external tooth profile of the product, the side of the tooth profile is Most of the fracture surface is not due to shearing, and a product with inferior accuracy is obtained. The present invention has been made in view of the above-described conventional situation, and has as its object to provide a cold forging die for a tooth-shaped part capable of obtaining a product with high accuracy while securing high working efficiency. I do.

[0016]

A cold forging die for a tooth part according to claim 1 is a cold forging die for a tooth part, which obtains a tooth part having an external tooth shape from a workpiece, wherein the cold forging die for the tooth part has an external tooth shape on the inner periphery. A flat die on which a corresponding mold surface is formed, and a circle which is located on one side in the axial direction of the flat die and inscribed in the outer tooth shape, is bounded by inner and outer 2
A flat die, the protruding die and the breakout punch, the flat die, the protruding die and the breakout punch being configured to divide the work into the flat die and the protruding die. After being sandwiched by the dies, the surface on the other axial side of the breakout punch is configured to protrude from the surface on the other axial side of the projection die.

In this forging die, after the workpiece is sandwiched between the flat die and the projection die, the other surface in the axial direction of the breakout punch projects from the surface on the other axial direction of the projection die. In this way, the workpiece is divided into a central portion, which is a product, and an edge, which is a remaining portion to be punched. At this time, since the breakout punch only has an outer peripheral surface having a cross section of a circle inscribed in the external tooth shape, it is not necessary to determine the phase between the flat die and the breakout punch in consideration of the engagement.
For this reason, high work efficiency can be ensured without troublesome phase determination.

Further, according to this forging die, the work initially has a shear surface formed on the entire surface of the teeth, and the work is slightly punched with the breakout punch and the flat die surface to form a slight addition to the tooth tips and tooth surfaces. Produces a fractured surface. Therefore, most of the tooth profile side will be sheared by the flat die mold surface,
Highly accurate products can be obtained. The cold forging die for a tooth-shaped component according to claim 2 is the cold forging die for a tooth-shaped component according to claim 1, wherein the projection die and the breakout punch further clamp the workpiece between the flat die and the projection die. The protruding die and the breakout punch are similarly lowered with respect to the work to make a cut with the flat die, and then the other axial surface of the breakout punch is the other axial surface of the protruding die. It is characterized by being configured to protrude more.

In this forging die, after the work is sandwiched between the flat die and the projection die, the projection die and the breakout punch are lowered in the same manner with respect to the work to make a cut with the flat die. The surface on the other side in the axial direction protrudes from the surface on the other side in the axial direction of the projection die. In this way, after the workpiece is cut by the die surface of the flat die, the center part as the product and the edge part as the remaining part are cut off.

The specifications of the tooth-shaped part suitable for working with the forging die according to the first and second aspects of the present invention are 0.5 to 2.0 modules, low teeth having 20 or more teeth, and a sheet thickness of the module. 3 to 10 times. If the tooth-shaped part is a bevel-shaped part, the torsion angle is 30 ° or less.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments 1 and 2 of the present invention will be described below with reference to the drawings. (Embodiment 1) As shown in FIGS. 1 and 2, the forging die of Embodiment 1 is for manufacturing a spur spline component having an external tooth shape parallel to the axial direction from a plate-shaped work W. . In this forging die, a ring-shaped flat die 2 is fixed to the upper surface of a lower die holder 1, and a die surface 2 a parallel to the axial direction corresponding to the external tooth shape is formed on the inner periphery of the flat die 2. A substantially cylindrical ejector punch 3 is provided in the flat die 2 so as to be movable up and down. A flat tooth portion 3a meshing with the mold surface 2a of the flat die 2 is formed on the outer periphery of the ejector punch 3. I have.

On the other hand, a ring-shaped projection die 5 is fixed to the upper die holder 4 above the flat die 2. The projecting die 5 has a projecting portion 5a projecting downward at the center of the lower end thereof, and a guide surface 5b having a cross section of a circle inscribed in the external tooth shape is formed on the inner periphery thereof. A substantially cylindrical breakout punch 6 having a guided surface 6a slidable along the guide surface 5b of the projection die 5 on the outer periphery of a lower end is provided in the projection die 5 so as to be vertically movable.

When manufacturing a spline spline with this forging die, the flat die 2 and the ejector punch 3 and the projection die 5 and the breakout punch 6 are first aligned, and then the flat die 2 and the ejector punch 3 are aligned. The work W is placed on a horizontal upper surface. By operating a ram (not shown), the projecting die 5 and the breakout punch 6 are held against the workpiece W until the work W is sandwiched between the flat die 2 and the ejector punch 3 and the projecting die 5 and the breakout punch 6. Lower it in the same way.

Further, the projecting die 5 and the breakout punch 6 are similarly lowered with respect to the work W, and a cut is made with the flat die 2. Immediately before the projection 5a of the projection die 5 comes into contact with the upper surface of the flat die 2, the lowering of the projection die 5 is stopped, while the lowering of the breakout punch 6 causes the breakout punch 6 to move into the mold surface 2a of the flat die 2. It is continued until it enters. As a result, breakout punch 6
Project from the lower surface of the projection die 5. Thus,
After the work W is cut by the mold surface 2a of the flat die 2,
The center part, which is a product (spline spline part), is separated from the edge part, which is the remaining part of the blank. At this time, since the breakout punch 6 only has an outer peripheral surface having a cross section of a circle inscribed in the external tooth shape, the flat die 2 in consideration of meshing is used.
And the breakout punch 6 need not be determined.

Thereafter, after the projection die 5 is raised while the breakout punch 6 is kept as it is, the ejector punch 3 is raised, so that the breakout punch 6 is also raised via the work W. Then, the product and the remaining portion of the blank are discharged from the flat die 2, and the breakout punch 6 is lifted to terminate the cold forging, and the product and the remaining portion of the blank are removed. For this reason, high work efficiency can be ensured without troublesome phase determination.

According to this forging die, the work W is
At the time of cutting, a shear surface is formed on the entire surface of the tooth, and a slight fracture surface is generated on the tooth tip and the tooth surface by punching with the breakout punch 6 and the mold surface 2a of the flat die 2 thereafter.
Therefore, most of the tooth profile side surface is the die surface 2 of the flat die 2.
As a result, a high-accuracy product can be obtained.

If a spline spline part is manufactured using this forging die, it is not necessary to form a spur tooth portion on the breakout punch 6, the projection die 5, and the ejector punch 3, so that the manufacturing cost of the die is low. Become. Further, since the breakout punch 6 and the projection die 5 have no spur teeth, there is no interference between them and the flat die 2, and the mold life is improved. (Embodiment 2) As shown in FIGS. 3 and 4, the forging die of Embodiment 2 is for manufacturing a bevel spline part having an external tooth shape along a helical winding from a plate-shaped work W. is there. In this forging die, a ring-shaped flat die 12 is fixed on the upper surface of a lower die holder 11.
A helical mold surface 12a corresponding to the external tooth shape is formed on the inner periphery of the helical member. A substantially cylindrical ejector punch 13 is provided in the flat die 12 so as to be vertically movable and rotatable in a horizontal plane by a bearing 14, and a large twist angle (15 ° or more) is provided on the outer periphery of the ejector punch 13. Therefore, the beveled teeth 13a meshing with the mold surface 12a of the flat die 12
Are formed. That is, in a product having a large torsion angle, the force required for the rotation accompanying the ascending is large, thereby easily increasing the tooth lead error. For this reason, the ejector punch 13 is formed with a beveled tooth portion 13a formed on the ejector punch 13 and engaged with the mold surface 12a of the flat die 12.
A rotational force is generated in the ejector punch 13 with the rise of the workpiece 3, and a rotational motion is given to the work W.

On the other hand, above the flat die 12, a ring-shaped projection die 17 is provided on the lower surface of the upper die holder 15 via a bearing 16 so as to be rotatable in a horizontal plane. The projection die 17 has a projection 17 projecting downward at the center of its lower end.
a is formed, and a guide surface 17b having a cross section of a circle inscribed in the external tooth shape is formed on the inner periphery thereof. A substantially cylindrical breakout punch 18 having a guided surface 18a slidable along the guide surface 17b of the projection die 17 on the outer periphery at the lower end is movable in the projection die 17 in a horizontal plane by a bearing 19. It is provided rotatably.

When a bevel spline is manufactured using this forging die, the flat die 12 and the ejector punch 13 are first used.
Then, the work W is placed on the horizontal upper surfaces of the flat die 12 and the ejector punch 13 after centering the projection die 17 and the breakout punch 18. By operating a ram (not shown), the projection die 17 and the breakout punch 18 are held against the work W until the work W is sandwiched between the flat die 12 and the ejector punch 13 and the projection die 17 and the breakout punch 18. Lower it in the same way. At this time, the projection die 17 and the ejector punch 18 do not rotate.

After the work W is sandwiched between the flat die 12 and the ejector punch 13, the projection die 17 and the breakout punch 18, the projection die 17 and the breakout punch 18 are further lowered to make a cut with the flat die 12. . At this time, since the work W is rotated for cutting by the flat die 12, the projection die 17 and the breakout punch 18 are also rotated. Immediately before the projection 17a of the projection die 17 comes into contact with the upper surface of the flat die 12, the lowering of the projection die 17 is stopped, while the lowering of the breakout punch 18 causes the breakout punch 18 to move into the mold surface 12a of the flat die 12. It is continued until it enters. As a result, the lower surface of the breakout punch 18 is
7 protrudes from the lower surface. In this way, after the work W is cut by the mold surface 12a of the flat die 12, the center portion, which is a product (helical spline part), and the edge, which is the remaining portion to be punched, are separated. At this time, since the breakout punch 18 has only an outer peripheral surface having a cross section of a circle inscribed in the external tooth shape, it is necessary to determine the phase between the flat die 12 and the breakout punch 18 in consideration of the engagement. Absent. At this time, since the product descends while rotating along the mold surface 12a of the flat die 12, the breakout punch 18
Is lowered while rotating, and the ejector punch 13
It is pushed by and descends while rotating.

Thereafter, after the projection die 17 is raised while the breakout punch 18 is kept as it is, the ejector punch 13 is raised, so that the breakout punch 18 is also raised via the work W. Then, the product and the remaining portion of the blank are discharged from the flat die 12, and the breakout punch 18 is lifted to terminate the cold forging, thereby removing the product and the remaining portion of the blank. For this reason, the same effects as those of the first embodiment can be obtained with this forging die.

If a bevel spline part is manufactured using this forging die, it is not necessary to form a particularly troublesome beveled part along the winding of the breakout punch 18 and the projection die 17, so that the die is not required. Production costs are particularly low. In addition, there is no interference of the bevel teeth, which is particularly likely to occur, and the mold life is particularly improved.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a forging die according to a first embodiment.

FIG. 2A relates to the forging die of the first embodiment, and FIG.
IA-IIA arrow plan view, (B) is IIB-II of FIG.
FIG.

FIG. 3 is a longitudinal sectional view of a forging die according to a second embodiment.

FIG. 4A relates to a forging die according to a second embodiment, and FIG.
VA-IVA arrow plan view, (B) is IVB-IV of FIG.
FIG.

FIG. 5 is a longitudinal sectional view of a conventional forging die.

6A relates to a conventional forging die, and FIG.
FIG. 6B is a plan view taken along the arrow VIA, and FIG. 6B is a plan view taken along the line VIB-VIB in FIG. 5.

FIG. 7 is a longitudinal sectional view of a conventional forging die.

8A is a diagram illustrating a conventional forging die, and FIG.
A-VIIIA arrow plan view, (B) is VIIIB of FIG.
It is a VIIIB arrow top view.

FIG. 9 is a longitudinal sectional view of a conventional punching die.

10A relates to a conventional punching die, and FIG.
FIG. 10B is a plan view as viewed in the direction of the arrow XA, and FIG. 10B is a plan view as viewed in the direction of the arrow XB-XB in FIG. 9.

[Explanation of symbols]

 W: Work 2a, 12a: Mold surface 2, 12: Flat die 6, 18 ... Breakout punch 5, 17: Projection die

Claims (2)

[Claims] 1. A flat forging die for a toothed part for obtaining a toothed part having an external tooth shape from a work, wherein a flat die having a die surface corresponding to the external tooth shape formed on an inner periphery, and a shaft of the flat die. In one of the directions, and the inner and outer 2
A flat die, the protruding die and the breakout punch, the flat die, the protruding die and the breakout punch being configured to divide the work into the flat die and the protruding die. A cold forging die for tooth profile parts, characterized in that, after being clamped by a die, the other surface in the axial direction of the breakout punch projects from the other surface in the axial direction of the projection die. 2. A projection die and a breakout punch,
After the work is sandwiched between the flat die and the projecting die, the projecting die and the breakout punch are similarly lowered with respect to the work to make a cut with the flat die, and then the axial direction of the breakout punch is determined. 2. The cold forging die for tooth profile parts according to claim 1, wherein the other surface is configured to project from the other surface in the axial direction of the projection die.