JP2021045783A - Press die and manufacturing method of work-piece - Google Patents

Abstract

To enhance strength of a work-piece while suppressing manufacturing costs.SOLUTION: A press die of a press device 10 presses a work-piece that is formed with bent portions 107. The press die comprises: corner portions 23 that abuts on the respective bent portions 107 when the work-piece 100 is pressed by the press device 10; and protrusions 24 that are formed continuously with each corner portion 23.SELECTED DRAWING: Figure 5

Description

The present invention relates to a method for manufacturing a press die and a work.

In a continuously variable transmission such as a hybrid vehicle, a forward / backward switching mechanism for switching the direction of input rotational driving force includes a bottomed cylindrical clutch drum. As an example of a method for manufacturing a clutch drum, a plate-shaped work piece is cut out in a circular shape and bent around the outer circumference to form a bottomed cylindrical shape.

Stress tends to concentrate on the bent portion formed by the bending process, which may shorten the product life of the clutch drum. Therefore, it has been proposed to perform shot peening on the bent portion (see, for example, Patent Document 1). Shot peening is a method of forming fine irregularities by colliding an iron ball with a metal surface. Since residual compressive stress is applied to the surface on which the unevenness is formed, the strength can be improved.

Jikkenhei 3-62619 Gazette

However, shot peening increases the number of manufacturing processes and may increase the manufacturing cost.

It is required to improve the strength of the work on which the bent portion is formed while suppressing the increase in the manufacturing cost.

The present invention is a press die for pressing a workpiece having a bent portion formed therein.
When pressing the work, the contact portion that comes into contact with the bent portion and the contact portion
A protrusion continuously formed on the contact portion is provided.

According to the present invention, since the unevenness can be formed in the bent portion by the press die, the strength of the work on which the bent portion is formed can be improved while suppressing the increase in the manufacturing cost.

(A) is a perspective view of the work, (b) is a plan view of the work, and (c) is a sectional view taken along the line AA of (a). It is a flowchart which shows the manufacturing method of the work which concerns on embodiment. It is a figure which shows the manufacturing process of a work. (A) shows the structure of the press apparatus of the rest-like process, and (b) is an enlarged view of the area A of (a). (A) is a diagram for explaining the operation of the press device, and (b) is an enlarged view of the region B of (a). It is a figure which shows the operation when the work is applied to a clutch drum.

1A is a perspective view of the work 100, FIG. 1B is a plan view of the work 100, and FIG. 1C is a cross-sectional view taken along the line AA of FIG. 1A. It is a figure.
As shown in FIG. 1A, the work 100 is a bottomed cylindrical member in which one end 101a of a cylindrical peripheral wall 101 is closed by a bottom wall 103 and the other end 101b is an open end. As shown in FIG. 1B, the bottom wall 103 is circular when viewed from the axis O direction, which is the axis of the work 100.
As shown in FIG. 1 (c), the peripheral wall 101 is erected in a substantially vertical direction from the outer peripheral edge 103a of the bottom wall 103 and extends parallel to the axis O.

The work 100 is made of a flat metal plate, and the bottom wall 103 and the peripheral wall 101 are connected by a bent portion 107 formed by bending the metal plate.

The bent portion 107 bends from the radial direction of the axis O toward the axis O direction. The bent portion 107 is marked with an R to form a curved surface.
The angle θ1 formed by the inner peripheral side of the peripheral wall 101 connected by the bent portion 107 and the bottom wall 103 is smaller than the angle θ2 formed by the outer peripheral side of the peripheral wall 101 and the bottom wall 103. In the following description, the surface of the bent portion 107 on the angle θ1 side is referred to as an “inner peripheral surface 107a”, and the surface of the bent portion 107 on the angle θ2 side is referred to as an “outer peripheral surface 107b”. Further, the angle θ1 is referred to as a “bending angle θ1” of the bent portion 107.

Dimples 108 are formed on the inner peripheral surface 107a of the bent portion 107. The dimples 108 are continuously and regularly arranged on the inner peripheral surface 107a over the entire circumference of the axis O in the circumferential direction. The dimple 108 is formed pinpointly on the inner peripheral surface 107a of the bent portion 107, and is not formed on the bottom wall 103 and the peripheral wall 101.

FIG. 2 is a flowchart showing a method of manufacturing the work 100 according to the embodiment.
As shown in FIG. 2, the work 100 is manufactured by a blanking step (step S01), a bending step (step S02), and a rest-like step (step S03).

FIG. 3 is a diagram showing a manufacturing process of the work 100, and shows a plan view and a cross-sectional view of each.
As shown in FIG. 3A, the work 100 is made of a flat metal plate 110 as a material. In the blanking step, the metal plate 110 is punched along the virtual line L1 to form the circular plate 120 shown in FIG. 3B.

In the bending step, the circular plate 120 is bent to one side in the thickness direction along the virtual line L2 on the inner diameter side of the outer peripheral edge to form the bottomed cylindrical work 100. The area Sb on the inner diameter side of the virtual line L2 and the area Sa on the outer peripheral side of the virtual line L2 of the circular plate 120 are the bottom wall 103 and the peripheral wall 101 of the work 100 shown in FIG. The boundary portion of the work 100 becomes the bent portion 107 of the work 100.

Although detailed description is omitted, the blanking step and the bending step can be performed by using a known press device. In the bending step, the work 100 may be bent stepwise in order to reduce the load applied to the bending portion 107.

The bending angle θ3 of the bending portion 107 of the work 100 molded in the bending step is in a state where there is a slight error with respect to the final bending angle θ1 shown in FIG. 1 (c). In the rest-like step, after the bending step, the work 100 is pressed again to improve the dimensional accuracy, and the work 100 having a bending angle θ1 is molded.

FIG. 4 (a) shows the configuration of the press device 10 in the rest-like process, and FIG. 4 (b) is an enlarged view of the region A of FIG. 4 (a).
As shown in FIG. 4A, the press device 10 includes an upper die punch 20 and a lower die 30 as a press die. The punch 20 and the die 30 are each supported by a holder (not shown).

The punch 20 and the die 30 are each cylindrical, and the die 30 has a larger diameter than the punch 20. The punch 20 and the die 30 are arranged so as to face each other in the X direction of the axis. The punch 20 is provided so as to be relatively accessible to and from the die 30 in the axis O direction passing through the axial center of the punch 20 by a drive mechanism (not shown).

A circular hole 32 is formed in the region of the upper surface 31 of the die 30 facing the lower end surface 21 of the punch 20 when viewed from the axis X direction.
The height Ha from the bottom surface 32a of the hole portion 32 to the opening surface 32b is set to be larger than the height H1 of the peripheral wall 101 of the work 100 (see (c) of FIG. 1).

The diameter Da of the inner peripheral surface 32c that stands substantially perpendicular to the bottom surface 32a of the hole 32 is set to a size that matches the outer diameter D2 (see (b) of FIG. 1) of the peripheral wall 101 of the work 100. Has been done.
The diameter Db of the outer peripheral surface 22 of the punch 20 is set to a size that matches the inner diameter D1 (see (b) of FIG. 1) of the peripheral wall 101 of the work 100.
Since the diameter Da of the inner peripheral surface 32c of the hole 32 is larger than the diameter Db of the outer peripheral surface 22 of the punch 20, when the punch 20 is driven toward the die 30, the punch 20 is inserted into the hole 32. ..

The lower end surface 21 and the outer peripheral surface 22 of the punch 20 are connected by a corner portion 23 on which an R is formed, and the R angle θ4 of the corner portion 23 is a bending angle θ1 on the inner peripheral side of the bending portion 107 of the work 100. It is set to match.

As shown in FIG. 4B, protrusions 24 are formed on the surface of the corners 23 of the punch 20 over the entire circumference in the circumferential direction centered on the axis X. The shape and arrangement of the protrusions 24 are not limited, but for example, spherical protrusions 24 are continuously and regularly arranged. The protrusion 24 can be formed by, for example, laser processing. The protrusion 24 is formed pinpointly on the surface of the corner portion 23 of the punch 20, and is not formed on the lower end surface 21 and the outer peripheral surface 22 of the punch 20.

FIG. 5 (a) is a diagram illustrating the operation of the press device 10, and FIG. 5 (b) is an enlarged view of the region B of FIG. 5 (a).
As shown in FIG. 5A, the work 100 is arranged in the hole 32 of the die 30. At this time, the bottom wall 103 of the work 100 is arranged so as to face the bottom surface 32a of the hole portion 32.
The punch 20 is driven toward the die 30 and inserted into the hole 32, the work 100 is sandwiched between the punch 20 and the die 30, and the work 100 is pressed from one side and the other side.

As shown in FIG. 5B, the corner portion 23 of the punch 20 abuts and presses against the inner peripheral surface 107a of the bent portion 107 of the work 100. By being pressed against the corner portion 23 having the R angle θ4 (see (a) of FIG. 4), the bent portion 107 of the work 100 is molded so as to have a bending angle θ1 (see (c) of FIG. 1). To.

Further, the protrusion 24 formed on the corner portion 23 is pressed against the inner peripheral surface 107a of the bent portion 107, and the shape of the protrusion 24 is transferred to the inner peripheral surface 107a of the bent portion 107. As a result, continuously arranged dimples 108 (see (c) in FIG. 1) are formed in the bent portion 107 of the work 100.

The work 100 molded by the above manufacturing method is not limited in its use, but is used, for example, in a clutch drum constituting a forward / backward switching mechanism in a continuously variable transmission such as a hybrid vehicle.

FIG. 6 is a diagram showing the operation when the work 100 is applied to the clutch drum.
As shown in FIG. 6, when the work 100 is used for the clutch drum, a through hole 102 is provided in the center of the bottom wall 103 in another step to form an inner wall 104 surrounding the through hole 102. A shaft (not shown) penetrating the through hole 102 is connected to the inner wall 104 and assembled inside the case of the transmission. A spline 106 is formed on the peripheral wall 101, and a plate (not shown) constituting the friction engaging element is spline-fitted.

In a continuously variable transmission, when the work 100 rotates integrally with a shaft (not shown) around the rotation axis Y, centrifugal force is applied to the work 100.
Centrifugal force acts on the work 100 as a tensile stress from the inner peripheral side to the outer peripheral side. As shown by the black arrows in FIG. 6, the tensile stress is particularly concentrated on the bent portion 107 of the work 100. This tensile stress tends to cause cracks in the bent portion 107, which may lead to metal fatigue.

Here, in the embodiment, the protrusion 24 of the punch 20 is transferred to the inner peripheral surface 107a of the bent portion 107 to form the dimple 108. As a result, compressive residual stress is applied to the bent portion 107 as shown by the white arrow in FIG. Since the compressive residual stress acts in the direction of closing the crack generated by the tensile stress, the strength of the bent portion 107 of the work 100 can be improved.

Since it is the inner peripheral surface 107a of the bent portion 107 that is likely to crack due to the tensile stress from the inner peripheral side to the outer peripheral side, in the embodiment, the dimple 108 is formed on the inner peripheral surface 107a of the bent portion 107. There is.

The dimple 108 can be formed by shot peening or the like, but it is necessary to add a separate process, which leads to an increase in manufacturing cost.

The inner peripheral surface 107a of the bent portion 107 is a portion pressed by the corner portion 23 of the punch 20 as shown in FIG. 5B in the rest-like step. Therefore, in the embodiment, by providing the protrusion 24 on the corner portion 23 of the punch 20, the protrusion 24 is transferred when the corner portion 23 presses the inner peripheral surface 107a of the bent portion 107. Thereby, the dimple 108 can be formed without adding another step.

As described above, the press die of the embodiment is
(1) The work 100 on which the bent portion 107 is formed is pressed.
When pressing the work 100, the corner portion 23 (contact portion) that abuts on the bent portion 107 and the corner portion 23 (contact portion)
A protrusion 24 formed continuously on the corner portion 23 is provided.

When the work 100 on which the bent portion 107 is formed is used, for example, as a clutch drum, tensile stress may be concentrated on the bent portion 107, causing cracks and shortening the product life of the work 100.
In the embodiment, by providing the protrusion 24 on the corner portion 23 that abuts on the bent portion 107, the protrusion 24 is pressed against the bent portion 107 at the time of pressing, and the dimple 108 can be formed on the bent portion 107. By forming the dimples 108, residual compressive stress is applied to the bent portion 107, and the strength of the bent portion 107 can be improved. As a result, the possibility of cracking when tensile stress is applied to the bent portion 107 can be reduced, and the product life of the work 100 can be improved.

Further, since the dimple 108 can be formed in the step of pressing the work 100, it is not necessary to add another step such as shot peening, and the product life of the work 100 can be improved while suppressing the manufacturing cost.

(2) The bent portion 107 of the work 100 is formed by bending the work 100 to one side in the thickness direction.
The press die is
A punch 20 (first mold) that presses one side of the work 100, and
A die 30 (second die), which is arranged to face the punch 20 die and presses the other side of the work 100, is provided.
The punch 20 has a corner portion 23 that presses the inner peripheral surface 107a (the surface on the inner peripheral side) of the bent portion 107 of the work 100 as a contact portion, and the protrusion 24 is continuously formed on the corner portion 23. ..

When tensile stress is applied to the bent portion 107 of the work 100, the stress is particularly likely to be concentrated on the inner peripheral surface 107a of the bent portion 107. Therefore, by forming protrusions 24 on the corners 23 of the punch 20 that presses the inner peripheral surface 107a of the bent portion 107, dimples 108 are formed on the inner peripheral surface 107a of the bent portion 107 to apply residual compressive stress. Can be done.

Further, by forming the dimple 108 pinpointly on the inner peripheral surface 107a of the bent portion 107, for example, when the work 100 is applied to the clutch drum, the dimple 108 is less likely to interfere with parts such as a plate and a shaft to be assembled to the clutch drum. ..

(3) The press die is used in a rest-like step in which the work 100 is rest-liked after the bending step of forming the bent portion 107.

The wrist-like step is a finishing step for improving the dimensional accuracy of the work 100 after the bending step, and is not a step of significantly deforming the work 100. Therefore, since the work 100 does not move much in the die during pressing, the protrusion 24 can be appropriately transferred to the bent portion 107 to form the dimple 108.

The effects described above are also applied to a method for manufacturing a work 100 in which a wrist-like process is performed by a press die of the embodiment.

100 Work 101 Peripheral wall 101a One end side 102 Through hole 103 Bottom wall 103a Outer peripheral edge 104 Inner wall 107 Bent part 107a Inner peripheral surface 107b Outer outer surface 106 Spline 108 Dimple 110 Metal plate 120 Circular plate 10 Press device 20 Punch 21 Lower end surface 22 Outer surface 23 Corner 24 Protrusion 30 Die 31 Top 32 Hole 32a Bottom 32b Opening 32c Inner circumference

Claims (4)

A press die that presses a workpiece with a bent portion.
When pressing the work, the contact portion that comes into contact with the bent portion and the contact portion
A press die including a protrusion continuously formed on the contact portion. The bent portion of the work is formed by bending the work to one side in the thickness direction.
The press die is
A first mold that presses the one side of the work, and
A second mold, which is arranged to face the first mold and presses the other side of the work facing the one side, is provided.
The first mold has a corner portion that presses the inner peripheral side surface of the bent portion of the work as the contact portion, and the protrusion is continuously formed on the corner portion. The press die according to claim 1. The press die according to claim 1 or 2, wherein the press die is used in a wrist-like step of rest-like the work after the bending step of forming the bent portion. This is a method for manufacturing a work in which a work having a bent portion is pressed by a pressing die to perform a wrist-like process.
The press die is
It has an abutting part where protrusions are continuously formed,
When the work is pressed by the press die, the protrusion is pressed against the bent portion by bringing the contact portion into contact with the bent portion of the work to form dimples in the bent portion. A method of manufacturing a workpiece, which is characterized by.

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