JPH01224132A - Forming method and its device - Google Patents

Abstract

PURPOSE:To prevent the crack generation of a die by giving a restraint from the external part to a die at the plastic working time of a blank and executing a knockout by removing or reducing the restraint thereof after completion of the plastic work. CONSTITUTION:The ring 43 for generating a restraint forming a die side taper face 39 on the outer periphery of the upper part of the die 21 and equipped with the taper face 41 corresponding to the taper face 39 at the outside thereof is arranged liftably. At the plastic working time of a blank 47, a pressing mechanism 45 is actuated by the descent of a slider 37 to move the ring 43 for generating a restraint downward. In this case, the blank 47 is worked with a large restraint being given to the die 21 via the abutting of the taper faces 39, 41. After completion of the work, the restraint of the die 21 is removed with the upward movement of the slider 37. The crack generation on the died 21 is thus prevented because the increase of the knockout force is restricted.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a forming method and an apparatus therefor, and in particular, the present invention relates to a forming method and an apparatus thereof, and in particular, after plastically working a material in accordance with the shape of a die hole formed in a die, The present invention relates to a molding method and apparatus for knocking out a molded material from a die hole to the outside.

[Conventional technology]

Generally, in molds for plastic working such as dies for cold forging,
During plastic working, very high pressure is applied to the inner surface of the die, so cracks often occur in the die.

Conventionally, in order to prevent the occurrence of such racks, for example, as shown in FIG.
The die 11 is reinforced by hardening or press-fitting.

According to such a method, the ring 13 is tightened by force, and the allowable internal pressure within the die hole 15 can be increased more than that of a single die 11.

[Problem to be solved by the invention]

However, with this traditional method ↓, ring 1
3, a large restraining force acts on the die 11 at all times, so there is a problem in that the knockout force for ejecting the material plastically worked within the die hole 15 of the die 11 to the outside increases.

That is, generally, the knockout pin used for knockout has a limited shape, so it is difficult to have sufficient strength, and there is a risk of breakage due to an increase in the knockout force.

Furthermore, the knockout force of the knockout pin is limited by the structure of the mold or the press machine, so there is a problem that if the required knockout force exceeds a predetermined value, it becomes difficult to eject the material.

Furthermore, if the strength of the plastically worked product is low, there is a problem that the product may be deformed by the knockout force during knockout.

The present invention solves the above-mentioned problems, and aims to provide a molding method and apparatus that can reliably prevent the occurrence of cracks in the die without increasing the knockout force. do.

[Means to solve the problem]

The forming method according to the present invention is a forming method in which a material is plastically worked in accordance with the shape of a die hole formed in a die, and then the plastically worked material is knocked out from the die hole. During processing, a restraining force is applied to the die from the outside, and after plastic working is completed, the restraining force is removed or reduced, and knockout is performed in this state.

Further, the molding device according to the present invention is a molding device that plastically works a material in accordance with the shape of a die hole formed in a die, and then knocks out the plastically worked material to the outside of the die hole. a die-side tapered surface formed on the outer periphery of the die-side tapered surface, and a constraining force-generating ring having an inner circumference having a ring-side tapered surface having a shape corresponding to the shape of the die-side tapered surface; and a pressing mechanism that presses the ring-side tapered surface of the ring toward the die-side tapered surface.

[For production]

In the forming method of the present invention, during the plastic working of the material, a restraining force is applied to the die from the outside to strengthen the die, while after the plastic working is completed, the restraining force is removed or reduced, and the plastically worked material is Knockout is performed with the restraining force on the target reduced.

In addition, in the forming apparatus of the present invention, during plastic working of the material, the ring-side tapered surface of the restraining force generation ring is fitted into the die-side tapered surface formed on the outer periphery of the die by the action of the pressing mechanism, Due to the pressure of the tapered surface on the ring side against the tapered surface on the die side, a large restraining force is applied to the die.
On the other hand, after the plastic working is completed, the pressure of the ring-side taper surface against the die-side taper surface is released, the restraining force acting on the die is removed or reduced, and knockout is performed in this state.

〔Example〕

Hereinafter, details of the present invention will be explained using the drawings.

FIG. 1 shows an embodiment of the molding apparatus of the present invention, in which the left side of the figure shows the state during molding, and the right side shows the state during knockout.

In this figure, reference numeral 21 indicates a die in which a die hole 23 is formed in the center.

This die 21 is fixed to a bolster 29 via a die holder 27 by a die fixing member 25. A through hole 33 through which a knockout pin 31 is inserted is formed in the center of the die holder 27, and the tip of the knockout pin 31 can be inserted into the die hole 23.

On the other hand, the lower end of a punch 33 is inserted into the die hole 23 of the die 21, and the upper end of this punch 33 is fixed to a punch holder 37 by a punch fixing member 35.

Therefore, in this embodiment, on the upper outer periphery of the die 21,
A die side tapered surface 39 is formed.

This die-side tapered surface 39 has a ring-side tapered surface 41 having a shape corresponding to the shape of the die-side tapered surface 39.
A ring-side tapered surface 41 of a restraining force generating ring 43 having a lower inner periphery is fitted therein.

This restraining force generating ring 43 is pressed by a pressing mechanism 45.
During plastic working of the material 47, the ring-side tapered surface 41 is pressed toward the die-side tapered surface 39.

That is, a guide member 49 is arranged around the outer periphery of the restraining force generating ring 43, and this guide member 49 is fixed to the punch holder 37.

An inner flange 51 is formed at the lower end of the guide member 49, and by abutting the flange 53 formed at the upper end of the restraining force generating ring 43 to the inner flange 51, the restraining force generating ring 43 is prevented from coming off downward. Note that the restraining force generating ring 43 is guided by a guide member 49 so as to be movable in the vertical direction.

The lower end of a pressing member 55 is in contact with the upper end of the restraining force generating ring 43, and the pressing member 55 is urged downward by an elastic body 57 such as a hydraulic cylinder or a spring. .

In the forming apparatus configured as described above, during plastic working of the material 47, the die 21 is moved by the action of the pressing mechanism 45.
The ring-side tapered surface 41 of the restraining force generating ring 43 is fitted onto the die-side tapered surface 39 formed on the outer periphery of the die 21 . , a large restraining force is applied.

That is, as the slider moves downward, the elastic body 57
and the restraining force generating ring 43 via the pressing member 55.
moves downward, the ring-side tapered surface 41 comes into contact with the die-side tapered surface 39, and a large restraining force is generated from the outside to the inside of the die 21.

On the other hand, after the plastic working is completed, the restraining force generating ring 43 is moved upward by the upward movement of the slider, and the pressure on the die side tapered surface 3g of the ring side tapered surface 41 is released. The restraining force acting on 241 is removed,
In this state, the knockout pins 3, I are moved upward, and the plastically worked material 47 is knocked out.

That is, in the molding apparatus configured as above,
During plastic working of the material 47, as shown in FIG. 2, a restraining force is applied to the die 21 by the restraining force generating ring 43, so that a punching force P is generated.

Therefore, the material 47 has σ. When the punch force is removed, the plastically worked material 47 has a stress of σ due to the restoring force of the die 21 itself, as shown in FIG. A smaller stress of σ1 acts on the die 21, causing a strain of ε, so if the plastically worked material 47 is to be discharged in this state, the coefficient of friction and the area of the outer peripheral surface of the material are added to σ1. It is necessary to have enough knock-a-la-toka to overcome the multiplied force, but in the present invention, as shown in the fourth doctor, at the time of knockout, the bird-bundling force does not act on die z1, so
A stress of σ□, which is smaller than σ1, acts on the plastically worked material 47, while stress ε, which is smaller than ε1, acts on the die 21.
Since the distortion occurs, the plastically worked material 47 can be ejected with a knockout force sufficient to overcome the force obtained by multiplying σ2 by the coefficient of friction and the area of the outer peripheral surface of the material.

Therefore, the molding apparatus configured as described above has a die-side tapered surface 39 formed on the outer periphery of the die 21 and a ring-side chie 8 surface 41 having a shape corresponding to the shape of the die-side tapered surface 39. a ring 43 for generating a restraining force around the periphery;
Since it has a pressing mechanism 45 that presses the ring-side tapered surface 41 of the restraining force generation ring 43 toward the die-side tapered surface 39 during plastic working of the material 47, the pressing mechanism 45 Due to this action, the ring-side tapered surface 41 of the restraining force generating ring 43 is fitted onto the die-side tapered surface 39 formed on the outer periphery of the die 21, and the ring-side tapered surface 41 is pressed against the die-side tapered surface 39. As a result, a large restraining force is applied to the die 21. On the other hand, after the plastic working is completed, the pressure of the ring-side tapered surface 41 on the die-side tapered surface 39 is released, and the restraining force acting on the die 21 is removed or removed. Since the knockout force is reduced and the knockout is performed in this state, it is possible to reliably prevent cracks from occurring in the die without increasing the knockout force.

Further, in the forming method according to the present invention, a restraining force is applied from the outside to the die 21 during plastic working of the material 47, and after the plastic working is completed, the restraining force is removed or reduced, and knockout is performed in this state. Material 4
7, a restraining force is applied to the die 21 from the outside, reinforcing the die 21, and making it possible to reliably prevent the die 21 from being cranked. On the other hand, after the plastic working is completed, the restraining force is removed or reduced, and knockout is performed with the restraining force on the plastically worked material 47 reduced, so the knockout force does not increase.

FIG. 5 shows another embodiment of the molding apparatus of the present invention. In this embodiment, the lower end of the guide member 61 is fixed to the upper surface of the bolster 29, and the guide member 61
A restraining force generating ring 63 disposed inside the lower elastic body 65
is urged upward by.

The restraining force generating ring 63 is urged downward by the main elastic body 67 via the pressing member 55, but the spring force of the main elastic body 67 is greater than the spring force of the lower elastic body 65. has been done.

In FIG. 5, the same members as those in FIG. 1 are designated by the same reference numerals, and detailed description thereof will be omitted.

In the forming apparatus configured as described above, during plastic working of the material 47, the die 21 is moved by the action of the pressing mechanism 45.
The ring-side tapered surface 41 of the restraining force generating ring 43 is fitted onto the die-side tapered surface 39 formed on the outer periphery of the die 21 . , a large restraining force is applied.

That is, since the spring force of the main elastic body 67 is larger than the spring force of the lower elastic body 65, as the slider moves downward, the restraining force generating ring 63 moves downward, and the ring side taper The surface 41 comes into contact with the die-side tapered surface 39, and a large restraining force is generated from the outside to the inside of the die 21.

On the other hand, after the plastic working is completed, the upward movement of the slider causes the pressing member 55 to move upward, and the elastic force of the lower elastic body 650 causes the restraining force generation ring 63 to move upward, and the ring-side tapered surface 41 The pressure on the die-side tapered surface 39 is released, the restraining force acting on the die 21 is removed, and in this state the knockout pin 31 is moved upward to knock out the plastically worked material 47.

Also in the forming processing apparatus configured as above, the first
Almost the same effect as the embodiment shown in the figure can be obtained.

In addition, in the embodiment described above, the restraining force generating ring 43
．． Although an example has been described in which the ring 63 is fitted from the upper side of the die 21, the present invention is not limited to such an embodiment. Of course, it is fine to do so.

〔Effect of the invention〕

As described above, the forming processing apparatus of the present invention has a die-side tapered surface formed on the outer periphery of the die, and a ring-side tapered surface with a shape corresponding to the shape of the die-side tapered surface on the inner periphery. It has a ring and a pressing mechanism that presses the ring-side tapered surface of the restraining force generating ring toward the die-side tapered surface during plastic processing of the material, so during plastic processing of the material, due to the action of the pressing mechanism, The ring-side tapered surface of the restraining force generation ring is fitted onto the die-side tapered surface formed on the outer periphery of the die, and a large restraining force is applied to the die by pressing the ring-side tapered surface against the die-side tapered surface. On the other hand, after the plastic working is completed, the pressure of the ring-side taper surface against the die-side taper surface is released, the restraining force acting on the die is removed or reduced, and knockout is performed in this state. , it becomes possible to reliably prevent cracks from occurring in the die without increasing the knockout force.

Furthermore, in the forming method according to the present invention, a restraining force is applied to the die from the outside during plastic working of the material, and
After plastic working is completed, the restraining force is removed or reduced and knockout is performed in this state, which has the advantage of reliably preventing cracks from occurring in the die without increasing the knockout force. .

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing an embodiment of the molding apparatus of the present invention. FIGS. 2 to 4 are schematic illustrations for explaining the present invention in detail. FIG. 5 is a longitudinal sectional view showing another embodiment of the molding apparatus of the present invention. FIG. 6 is an explanatory diagram showing a conventional crack prevention method. [Explanation of symbols of main parts] 21...Die 23...Die hole 33...Punch 39...Die side tapered surface 41...Ring side tapered surface 43...Ring for generating restraint force 45...Press mechanism 47...Material. Figure 1 Figure 5

Claims (2)

[Claims] (1) In a forming method in which a material is plastically worked in accordance with the shape of a die hole formed in a die, and then the plastically worked material is knocked out from the die hole, when the material is plastically worked, the material is A forming method characterized in that a restraining force is applied from the outside, and after plastic working is completed, the restraining force is removed or reduced, and knockout is performed in this state. (2) A die side formed on the outer periphery of the die in a molding device that plastically processes a material following the shape of a die hole formed in the die and then knocks out the plastically processed material from the die hole. a restraining force generating ring having a tapered surface and a ring side tapered surface having a shape corresponding to the shape of the die side tapered surface on an inner periphery; and a ring side tapered surface of the restraining force generating ring during plastic working of the material. A molding processing apparatus comprising: a pressing mechanism that presses toward the die-side tapered surface.