JP2000006053A - Die for center punch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a die for center punch whose press force is roughly constant and which will leave no nicks regardless of board thickness. SOLUTION: This die for center punch is provided with a punch guide 37 mounted on a punch holder 7 supported on a die holder 40 in a vertically movable condition through a plurality (N) of lifter springs 51, a center punch 35 energized downward by a punch spring 39 so as to protrude from the punch guide, a sleeve 17 so as to engage with a large-diameter part 11 on the upper side of the punch holder, and a board retaining spring 27 mounted between the punch head of a center shaft 19 supported so as to move vertically on the sleeve 17 and the punch holder. The relation between the loads of three types of springs is as follows: P2-(N*P1)>=P3, where the mounting loads of a plurality (N) of lifter springs, the board press spring and the punch spring are taken as P1, P2, P3 respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a center punch mold. More specifically, the present invention relates to a mold used for a punch press.

[0002]

2. Description of the Related Art A center punch die is used for marking a center position of a drilling process, displaying a bent position of a bending process (indicating some points), or displaying a position for a welding process. . A center punch mold related to the present application is disclosed in Japanese Utility Model Publication No. 61-17830.

The center punch die disclosed in the above-mentioned Japanese Utility Model Publication No. 61-17830 is designed to prevent the bottom from protruding even if the thickness of the workpiece changes. The purpose is to prevent the stamping depth of the punch from changing even when the thickness changes, and the outline of the configuration is as follows.

[0004] A center punch (33) is provided at the lower end of a punch holder (7), which is movably supported on the upper die supporting portion of a punch press, and the punch holder is urged upward. A punch rod (21) provided between the punch holder (7) and the punch holder (7), which is supported by the punch holder so as to be movable up and down; A center punch mold, characterized in that a protrusion amount adjusting member (41) for relatively adjusting the protrusion amount of the center punch (33) is attached to a lower portion of the holder. "

[0005] In addition to the center punch mold described in Japanese Utility Model Publication No. 61-17830, a mold without a protrusion amount adjusting member for adjusting the protrusion amount of the center punch (33) may be used. .

[0006]

In the above-mentioned prior art (Japanese Utility Model Publication No. Sho 61-17830), when the range of the plate thickness of the workpiece is large, the change in the deflection of the spring (31) becomes large, and the center punch is changed. The load applied to (33) also changes greatly.

Therefore, in order to make the load applied to the center punch (33) substantially uniform even when the plate thickness changes, two or three sets of center punch dies corresponding to the plate thickness are prepared (thin plate, medium thickness). , For thick plates, etc.).

Further, in the case of a thick plate made of a soft material such as aluminum, there is also a problem that the pressing force of the plate becomes large and dents are formed by the punch holder (7).

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and an object of the present invention is to maintain a substantially constant pressing force applied to a center punch irrespective of the thickness of a workpiece. It is also an object of the present invention to provide a center punch die that does not leave a dent due to plate pressing on a workpiece.

[0010]

According to a first aspect of the present invention, there is provided a center punch mold which is supported on a mold holder via a plurality of (N) lifter springs so as to be vertically movable. A punch guide is provided at the lower end of the punch holder provided, and a center punch urged downward by a punch spring provided in the punch holder is provided so as to protrude and retract from the punch guide, and an inner diameter of the upper side of the punch holder is provided. A sleeve is fitted to the part and provided,
The gist of the present invention is that a plate holding spring is provided between a punch head and a punch holder of a center shaft which is vertically movably supported by the sleeve.

[0011] The center punch mold according to claim 2 is
2. The center punch mold according to claim 1, wherein the plurality of (N) lifter springs, plate holding springs, and punch springs have mounting loads of P, respectively.
When it is assumed that 1, P2, and P3, the relationship between the loads of the three types of springs is that P2− (N * P1) ≧ P3.

Therefore, according to the center punch die of the first aspect, the pressing force from the ram of the punch press is transmitted to the center punch via the plate holding spring and the punch spring, so that the plate of the workpiece is formed. Even if the thickness changes, the pressing force of the center punch can be made substantially constant. As a result, even if the plate thickness of the workpiece changes, a center punch (mark) having a fixed size can be punched if the material is the same.

According to the center punch die of the second aspect, the load of the plate pressing spring is calculated by the above-mentioned relational expression (1).
Therefore, no dents are left on the surface of the workpiece.

[0014]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an embodiment of a center punch die according to the present invention. As shown in FIG. 1, the center punch die 1 is provided to face a die 5 (lower die) supported by a die holder 3.

The above-described punch holder 7 of the center punch mold 1 is a cylinder having a flange 9 at an upper end portion.
The inner diameter of the cylinder from the center in the vertical direction to the upper part is
The lower part is formed in the small diameter part 13.

In the large diameter portion 11, one side of a sleeve 17 provided with a flange 15 at a substantially central portion of the outer diameter portion is located at a position where the flange 9 of the punch holder 7 and the flange 15 of the sleeve 17 abut. Inserted up to.

A center shaft 19 having a head at the lower end is slidably fitted from below the sleeve 17 on the inner diameter portion of the sleeve 17, and the center shaft 19 protrudes upward from the sleeve 17. Male thread 2 at the upper end
1 is provided with a punch head 23 by screwing, and a plate holding spring 27 made of a compression spring is elastically mounted between the flange portion 25 of the punch head 23 and the sleeve 17.

The above-mentioned sleeve 17 is prevented from coming off by a set screw 29 provided on the flange 9 of the punch holder 7. The punch head 23 is prevented from rotating by a set screw 31 provided on the flange portion 25.

At the lower end of the punch holder 7, a screw hole 33 is provided concentrically with the small diameter portion 13.
A punch guide 37 for guiding the center punch 35 is screwed into the screw hole 33.

A center punch 35 is slidably fitted to the above-mentioned punch guide 37, and a flange provided at the upper end of the center punch 35 is
7 to prevent the center punch 35 from coming off the punch guide 37.

A punch spring 39 made of a compression spring is elastically mounted between the flange provided at the upper end of the center punch 35 and the small-diameter portion 13 provided in the inner diameter hole below the punch holder 7. The lower end of the center punch 35 is sharply formed, and its tip projects from the punch guide 37 by a fixed amount (h).

Incidentally, Generally, the protrusion amount (h) is 0.5 mm, and the diameter of the center punch hole (mark) is about 1 mm.

The center punch die 1 as described above is, for example, a die mounting hole 41 of a die holder 40 of a punch press.
The punch holder 7 is mounted slidably in the vertical direction.
At this time, the flange 9 of the punch holder 7 is supported at a fixed height by a vertically movable die supporting means 43 provided on the die holder 40.

The structure of the mold supporting means 43 is such that a shoulder screw 47 is provided upright in a counterbore hole 45 provided in the mold holder 40, and a flanged bush 49 is fitted to the shoulder screw 47 so as to be movable up and down. The lifter spring 51 is elastically provided between the flanged bush 49 and the counterbore hole 45.

A key 57 fixed to a counterbore hole 53 below the mold holder 40 with a bolt 55 is slidably engaged with a key groove 59 provided on the outer periphery of the punch holder 7 in a vertical direction. 7 is for restricting rotation around the axis.

The mold supporting means 43 is usually arranged at three points around the upper mold in order to smoothly move the upper mold up and down. However, the arrangement is not limited to the three-point arrangement. Not
It may be arranged at two or more places.

It is desirable to set the mounting load (P2) of the plate pressing spring 27 as small as possible according to the following relational expression (1).

[0029]

P1- (N * P1) ≧ P3 (1) In the above relational expression (1), N = 2, 3, 4,
………, P1: Mounting load of lifter spring 51,
P2 is the mounting load of the plate holding spring 27, and P3 is the mounting load of the punch spring 39.

Therefore, the mounting load (P2) of the plate pressing spring 27 in the embodiment is P2 = P3 + (3
* P1) is set.

A description will be given of a case where center punching is performed on a workpiece in the center punch mold 1 having the above configuration.

After the workpiece is positioned immediately below the center punch die 1, a ram 61 of a punch press (not shown) is used.
When the punch descends and presses the punch head 23, the punch holder 7 applies the urging force (3) of the three lifter springs 51.
* P1), the center punch 35 comes into contact with the surface of the workpiece W.

After the contact, the ram 61 is moved to the center shaft 19
Further, the plate pressing spring 27 is compressed, and the pressing force from the ram is transmitted to the center punch 35 via the plate pressing spring 27 and the punch spring 39.

Therefore, the pressing force applied to the center punch 35 is a load generated when the punch spring 39 is bent, and is a substantially constant pressing force. The plate pressing force is a load obtained by subtracting the load (3 * P1) generated from the three lifter springs 51 from the load generated by the plate pressing spring 27.

Therefore, even if the thickness of the workpiece changes,
Since the pressing force of the center punch 35 can be maintained substantially constant, a center punch (mark) M having a fixed size can be punched if the material is the same.

Further, since the load of the plate pressing spring 27 is set as small as possible in accordance with the above-mentioned relational expression (1), no dent is left on the surface of the workpiece.

[0037]

According to the first aspect of the present invention, since the pressing force from the ram of the punch press is transmitted to the center punch via the plate holding spring and the punch spring, the plate thickness of the workpiece changes. However, the pressing force of the center punch can be made substantially constant. As a result, even if the plate thickness of the workpiece changes, if the material is the same, a center punch (mark) M of a fixed size can be punched.

According to the second aspect of the present invention, since the load of the plate pressing spring is set as small as possible according to the above-mentioned relational expression (1), no dent is left on the surface of the workpiece.

[Brief description of the drawings]

FIG. 1 shows an embodiment of a center punch mold according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Center punch die 3 Die holder 5 Die 7 Punch holder 9, 15, 25 Flange 11 Large diameter portion 13 Small diameter portion 17 Sleeve 19 Center shaft 23 Punch head 27 Plate holding spring 29, 31 Set screw 35 Center punch 37 Punch guide 39 Punch spring 40 Mold holder 41 Mold mounting hole 43 Mold support means 47 Shoulder screw 49 Flanged bush 51 Lifter spring 57 Key 59 Key groove 61 Ram M Engraved W Workpiece

Claims (2)

[Claims] 1. A punch guide is provided at the lower end of a punch holder which is supported on a mold holder via a plurality of (N) lifter springs so as to be movable up and down. A biased center punch is provided so as to protrude and retract from the punch guide, a sleeve is fitted to an upper inner diameter portion of the punch holder, and a center shaft punch supported movably up and down by the sleeve. A center punch mold having a plate holding spring provided between a head and a punch holder. 2. When the mounting loads of the plurality of (N) lifter springs, plate holding springs and punch springs are P1, P2, and P3, respectively,
The relationship between the types of spring loads is P2- (N * P1) ≧
The center punch mold according to claim 1, wherein the center punch mold is P3.