JPH0734964B2 - dice - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a die for forming bolts, nuts and other mechanical parts by press forming.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG.
Reinforcing case for upper mold (2) and lower mold (3) with mold holes (22)
Fit into the taper hole (10) of (1), further insert the intermediate lifting base (4), and press the upper die (2) and the upper die (2) through the intermediate lifting base (4) with a pressure jig (not shown). Lower mold (3) is press-fitted and further reinforced case
The tightening screw (5) is screwed onto (1) to prevent the intermediate lifting table (4) from coming off.

Guided by the tapered hole (10) of the reinforcing case (1), the cores of the upper and lower molds (2) and (3) are surely aligned with each other. Also, upper and lower type
(2) The elastic return force due to the release of the pressure applied to (3) and the intermediate push-up base (4) always acts on the tightening screw (5) to obtain the effect of preventing the tightening screw (5) from loosening.

[0004]

The above-mentioned conventional dice are
When the upper mold (2) and the lower mold (3) are butted against each other, the taper surface is polished, and when the upper and lower molds (2) and (3) are press-fitted into the reinforcing case (1), the upper and lower molds are pressed against each other. Make sure that the butt surfaces are in close contact.

However, the upper mold is damaged due to local damage of the mold.
When it is necessary to replace either one of (2) and the lower die (3), not only the taper angle but also the diameter dimensions of the upper and lower die butting surfaces must be exactly matched. However, there has been a problem that high-precision processing is required and the cost of die manufacturing becomes high. The present invention clarifies a die that can solve the above problems by making the taper angles of the upper die and the lower die different from each other.

[0006]

According to the die of the present invention, the upper die (2) and the lower die (3) having the die hole (22) are press-fitted into the taper holes of the reinforcing case (1) to form the reinforcing case (1). In the die in which the tightening screw (5) is screwed in, the taper angle of the outer peripheral taper surface (36) of the lower mold (3) is smaller than that of the outer peripheral taper surface (21) of the upper mold (2). The taper hole of the case (1) includes a first taper hole (11) corresponding to the taper surface (21) of the upper die (2) and a second taper hole corresponding to the taper surface (36) of the lower die (3). It is composed of (12) and.

[0007]

[Operation and effect] Upper mold (2) and lower mold in the reinforcing case (1)
When (3) is fitted and pressure is applied from the lower mold (3) side to the upper mold (2) side,
That is, when the same pressing force is applied to the lower mold (3) and the upper mold (2), the taper surfaces (21) (36) of the upper and lower molds stretch the taper holes (11) (12) in the radial direction for reinforcement. The force for elastically deforming the case (1) and the amount of diameter-reducing elastic deformation of the die itself are larger in the lower die (3) having a smaller taper angle of the outer peripheral tapered surface than in the upper die (2). In other words, the upper die (2) and the lower die (3) are connected to the tapered holes (11) (1
When pushed up in close contact with 2), the reinforcement case (1) is elastically deformed, and the allowable amount to advance in the axial direction due to the plastic deformation of the mold itself is that the lower mold (3) has a smaller taper angle. It is larger than the upper mold (2) with a large angle.

Therefore, the upper mold (2) and the lower mold (3) are reinforced by a case.
Even if there is a gap between the abutting surfaces of the lower die (3), the size of the gap pushes up the lower mold (3) when it is pushed into the tapered holes (11) and (12) of (1) by hand. Elastically deform the reinforcing case (1), and if the lower mold (3) is less than the allowable amount by the elastic deformation of the mold itself, the lower mold is strongly pressed.
The upper mold (2) and the lower mold (3) can be press-fitted by advancing the (3) and abutting the upper mold (2).

As described above, the upper mold (2) and the lower mold (3) are pushed into the reinforcing case (1) by hand, and the respective tapered surfaces (21) and (36) are tapered holes (11) and (12). Since the abutting surfaces of the upper and lower dies do not necessarily have to be in close contact with each other, the outer peripheral taper surfaces (21) and (36) of the upper die (2) and the lower die (3) are different from the conventional case. Compared with the case where the taper angles are the same, the upper mold (2) and the lower mold
The processing accuracy of (3) is not required to be high, and the processing becomes easy and the cost can be reduced.

The upper and lower molds (2) and (3) have outer peripheral taper surfaces (21) and (3).
The larger the taper angle of 6) is, the larger the force to get out of the taper hole becomes. However, by making the taper angle of the lower mold (3) smaller than that of the upper mold (2) as in the present invention. Further, the force acting on the lower die (3) itself to escape from the tapered hole is weakened, and the upper die (2) can be prevented from coming off.

Further, the taper surface (36) of the lower mold (3) is the upper mold (2).
Since the taper angle is smaller than the taper surface (21) of
(2) Compared with the case where the taper angles of (3) are the same, the lower mold
The diameter of the large diameter portion of (3) can be reduced. Therefore, the minimum thickness of the portion of the reinforcing case (1) corresponding to the second taper hole (12) can be increased, and the reinforcing effect of the reinforcing case (1) can be enhanced.

FIG. 1 shows a first embodiment. The reinforced case (1) is made of hardened steel having a high tensile strength and a soft hardness, and is formed into a tubular shape. The first tapered hole (1
1), the second taper hole 12 and the inner screw hole 13 are opened. Incidentally, it is a known fact that the molding material is punched from the tip side of the reinforcing case (1), and the description thereof is omitted.

The small diameter side of the first taper hole (11) is a reinforcing case.
The second taper hole (12) is open at the front end surface of (1) and the smaller diameter side is directed toward the larger diameter side of the first tapered hole (11). The large diameter side diameter of the first taper hole (11) is smaller than the small diameter side diameter of the second taper hole (12). Further, the taper angle of the first taper hole (11) is 3 to 10 ° with respect to the axis, and the taper angle of the second taper hole (12) is 1 to more than the taper angle of the first taper hole (11). 7 ° small. The taper angles of the upper and lower molds (2) and (3) may be optimally selected depending on factors such as the length of the mold in the axial direction.

The upper die (2) is press-fitted into the first taper hole (11) of the reinforcing case (1) and the lower die (3) is press-fitted into the second taper hole (12).
The upper die (2) is made of cemented carbide and has an outer peripheral surface which is a tapered surface (21) corresponding to the first tapered hole (11), and a through die hole (22) is formed in the shaft core. In the upper die (2), the front end surface is aligned with the front end surface of the reinforcing case (1) in the press-fitted state, and the rear end is the first taper hole.
It is formed in a size protruding from (11).

The lower die (3) comprises a tubular lower die main body (31) and a holder (32) for press-fitting and holding the main body. Lower die (3
1) is made of cemented carbide, the outer circumference is a straight cylindrical surface,
The mold hole (22) of the upper mold (2) is formed in the center of the surface facing the upper mold (2) side.
Forming a continuous mold cavity (33).

The holder (32) has a receiving hole (35) at the center of the front end surface.
The lower die main body (31) is press-fitted into the receiving hole (35), and the outer periphery extends from the tip to a position slightly beyond the central portion to the second taper hole (12) of the reinforcing case (1). ) Corresponding taper surface
(36) and the rear part is a small diameter straight shaft (37).

A pin insertion hole (34) is formed so as to protrude through the shaft center of the holder (32) and the lower die main body (31). Lower mold
The axial length of the tapered surface (36) of (3) is the same as the reinforcing case (1).
Is slightly larger than the axial length of the second tapered hole (12).

The tightening screw (5) screwed into the inner screw hole (13) of the reinforcing case (1) has a through hole (53) in which the small-diameter straight shaft portion (37) of the holder (32) fits in the shaft core. ) Is opened, and an outer screw (51) and a rotary tool engaging portion (52) are provided on the outer circumference.

Then, the upper mold (2) and the lower mold (3) are fitted to the reinforcing case (1), and the tightening screw (5) is fitted to the straight shaft portion (37) of the lower mold (3). The lower die (3) is pressed by a pressure jig (not shown), and the upper die (2) and the lower die (3) are respectively attached to the first taper hole (1
1) Press-fit into the second taper hole (12). The pressure screw is tightened in the inner screw hole (13) of the reinforcing case (1) to release the pressure. First taper hole (11) and second taper hole
Since (12) is formed concentrically, the cores of the upper and lower molds (2) and (3) are surely aligned.

The lower mold (3) is pressurized, and the upper mold is passed through the lower mold (3).
When (2) is pushed up, that is, when the same pushing force is applied to the lower die (3) and the upper die (2), the upper and lower taper surfaces (21) (36)
Reinforce the case by stretching the taper holes (11) (12) in the radial direction.
The force of elastically deforming (1) to push it outward and the amount of elastic deformation of the mold itself are larger in the lower mold (3) with a smaller taper angle on the outer peripheral taper surface than in the upper mold (2). Is. In other words, when the upper die (2) and the lower die (3) are pushed up in close contact with the tapered holes (11) and (12), the reinforcing case (1) is elastically deformed, and the elastic deformation of the die itself causes The amount of movement in the axial direction is larger in the lower die (3) having a smaller taper angle than in the upper die (2) having a large taper angle.

Therefore, the upper mold (2) and the lower mold (3) are reinforced by a case.
Even if a gap is created between the abutting surfaces of the taper holes (11) and (12) of (1) by hand, the gap causes the reinforcing case (1) to elastically deform and lower. If the mold (3) is less than the amount that can be advanced, the lower mold (3) is advanced and abutted against the upper mold (2) by strong tightening with the tightening screw (5).
(2) and lower mold (3) can be press-fitted.

The elastic deformation amount of the reinforcing case (1) against the tightening force of the upper mold (2) and the lower mold (3) and the elastic deformation amount of the mold itself are stored in a database for various taper angles. The upper mold (2) and the lower mold (3) can be individually processed for each size.

As described above, the upper die (2) and the lower die (3) are manually pushed into the reinforcing case (1) so that the respective taper surfaces (21) and (36) become the taper holes (11) and (12). Since the upper and lower butt surfaces do not necessarily have to be in close contact with each other in the close contact state,
The machining accuracy of the upper mold (2) and the lower mold (3) is higher than that when the taper angles of the outer peripheral tapered surfaces (21) (36) of the upper mold (2) and the lower mold (3) are the same. Is not required, processing becomes easy, and cost can be reduced.

Since the upper mold (2) and the lower mold (3) are press-fitted in the reinforcing case (1) in the same manner as in the conventional case, both of the upper mold (2) and the lower mold (3) are The upper and lower molds can be added with the reinforcing effect of the reinforcing case (1) and by releasing the pressure during press fitting.
(2) The elastic return force of (3) acts on the tightening screw (5) to provide a locking effect.

Further, the upper and lower molds (2) and (3) have outer peripheral taper surfaces (21) and (3).
The larger the taper angle of 6) is, the larger the force to get out of the taper hole becomes. However, by making the taper angle of the lower mold (3) smaller than that of the upper mold (2) as in the present invention. Further, the force acting on the lower die (3) itself to escape from the tapered hole is weakened, and the upper die (2) can be prevented from coming off.

If the taper surface of the lower die (3) is made as small as possible, it becomes a straight shaft. In the case of a straight shaft, when it is press-fitted into the reinforcing case (1), seizure occurs at the time of press-fitting and the reinforcing case (1) The inner surface of) is rough and the case cannot be used repeatedly.

If a clearance is provided between the straight shaft and the hole of the reinforcing case (1), the lower die (3) is misaligned. Further, when the clearance is provided, the straight shaft portion expands and contracts in the radial direction each time it is forged, which causes a problem of seizure with the reinforcing case (1). However, in the present invention, the outer periphery of the lower die (3) is Since it is a taper surface, the problem as in the case of the straight shaft portion can be eliminated.

When either the upper die (2) or the lower die (3) is damaged and needs to be replaced, the bottom surface of the holder (32) is pressed again and the tightening screw (5) is attached. The elastic pressing force acting is released, the tightening screw (5) is loosened, the upper die (2) is pressed from the outside of the die in the direction of removal, and the upper die (2) and the lower die (3)
Remove. It is sufficient to replace the damaged upper mold (2) or lower mold (3) with a new one and install it in the reinforcing case (1) by the same procedure as above.

FIG. 2 shows a second embodiment, in which the upper die (2)
A taper sleeve (23) is fitted around the outer periphery of the. sleeve
(23) is reinforced case (1) because cracking occurs when hardness is high.
It is formed from a special steel that is even softer than the above.

FIG. 3 shows a third embodiment, which is the second embodiment.
It is a modification of the embodiment. Lower mold mainly on ring holder (32)
The lower die (3) is formed by press-fitting the (31), and the upper die (2) and the lower die (3) are inserted into the first taper hole (11) and the second taper hole via the intermediate lifting table (4). It is pressed into (12).

FIG. 4 shows a fourth embodiment, which is the third embodiment described above.
It is a modification of the embodiment. The upper mold (2) is formed by stacking the front upper mold (24) and the rear upper mold (25), and the front upper mold (24) and the rear upper mold (2
The outer peripheral taper surface of 5) has the same taper angle and is press-fitted into the taper sleeve (23).

FIG. 5 shows a fifth embodiment, in which the first
It is a modification of the embodiment. The lower mold (3) is formed by stacking the first lower mold (7) and the second lower mold (8), and both the first and second lower molds (7) and (8) are ring-shaped holders (71) (81). ) Is formed by press-fitting the die main body (72) (82), and the peripheral surface is a taper surface (36) with the same taper angle, and is tightened by the tightening screw (5) through the intermediate lifting table (4). It is press-fitted into the second taper hole (12).

The common points of the second to fifth embodiments are that the outer peripheral tapered surface (36) of the lower mold (3) has a smaller taper angle than the outer peripheral tapered surface (21) of the upper mold (2). That is, the same effect as the first embodiment is obtained. The present invention is not limited to the above embodiments, and various modifications can be made within the scope of the claims.

[Brief description of drawings]

FIG. 1 is a sectional view of a first embodiment.

FIG. 2 is a sectional view of a second embodiment.

FIG. 3 is a sectional view of a third embodiment.

FIG. 4 is a sectional view of a fourth embodiment.

FIG. 5 is a sectional view of a fifth embodiment.

FIG. 6 is a sectional view of a conventional example.

[Explanation of symbols]

 (1) Reinforcing case (11) First taper hole (12) Second taper hole (2) Upper mold (3) Lower mold (5) Tightening screw

Claims (2)

[Claims] 1. An upper die (2) and a lower die (3) having die holes (22) formed therein.
In the die in which the reinforced case (1) is press-fitted into the taper hole, the outer peripheral taper surface (21) of the upper die (2) and the outer peripheral taper surface (36) of the lower die (3) both have the small diameter side end surface facing the driving side. Moreover, the taper angle of the outer peripheral taper surface (36) of the lower mold (3) is smaller than that of the outer peripheral taper surface (21) of the upper mold (2).
The taper hole of (1) is a first taper hole (11) corresponding to the taper surface (21) of the upper mold (2), coaxial with the first taper hole (11), and the lower mold (3). Second tapered hole (1) corresponding to the tapered surface (36) of
2) Dice composed by and. 2. The reinforcing case (1) has a second taper hole (12).
The die according to claim 1, wherein a tightening screw (5) is screwed to face the end surface of the large diameter side of the die.