JPS60213321A - Press die - Google Patents

Abstract

PURPOSE:To execute a work having high accuracy without causing a burr, etc., by overcoming an added force with providing an elastic body to a piercing die in a press die performing a piercing work and burring work in one stage. CONSTITUTION:An elastic body 13 is provided between a flange part 11 of a piercing die 10 of a press die and a stepped part 12 of a lower holder 5. First a work W is arranged onto a burring die 6 and the lower surface of a piercing work part 2a is brought into contact with the work W with descending an upper holder 4, and a hole Wa is made on the work W with the co-operation of the piercing work part 2a and a piercing die 10. Then a pierce burring punch 2 is descended further and a cylindrical burring part Wb is formed on the work W with the co-operation of the burring die 6 with binding the work W by the piercing die 10. In this case since the elastic body 13 having sufficient elastic power to overcome the force that the piercing die 10 receives is provided, piercing part and burring part having high accuracy can be formed.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a piercing process for making a hole in a workpiece,
The present invention relates to a press mold that performs burring processing in which the thus-processed hole is pilot-drilled to form a cylindrical flange.

(Prior Art) When performing burring to form a cylindrical flange on a plate-shaped workpiece, usually a pilot hole is formed in the workpiece using a press mold having a piercing punch and a piercing die, and then the workpiece is used with a burring punch. The burring process is performed by installing a separate press mold with a burring die, but in order to improve processing accuracy and processing efficiency, a press that performs piercing and burring processes in one process with a single press mold. A model has been developed.

FIGS. 1(A) and 1(B) are diagrams showing a press die 1 conventionally used to perform these processes simultaneously in one process, and in which a pierced part 2a and a burring part 2b with a larger diameter are formed. A pierce burring punch 2 having a pierce burring punch 2 is attached to an upper holder 4 by a retainer 3, and the pierce burring punch 2 is vertically movable by the upper holder 4.

A burring die 6 is attached to the lower boulder 5 fixed below the upper holder 4, and the burring die 6 has a hole 6a that cooperates with the burring part 2b of the piercing burring punch 2 to perform burring on the workpiece W. is formed. Further, a blank holder 7 is attached to the upper holder 4 to hold the work W between it and the burring die 6, and a coil spring is attached to the blank holder 7 to provide elastic force for pressing the work W. 8 is attached, and a stopper 9 for regulating the lower limit of the blank holder is also attached.

FIG. 1(A) is a diagram showing a state in which piercing has been performed using the press die 1, and FIG. 1(B) is a diagram showing a state in which burring has been performed after the piercing. In such a conventional press die 1, since the clearance between the piercing part 2a and the burring die 6 must be large, the workpiece W is not restrained during piercing, and the pierced workpiece Burring occurs on the inner peripheral surface of the hole Wa of W, and as shown in Fig. 1 (C), a crack C occurs in the burring part wb after burring, and the height H of the burring wb also becomes uneven, resulting in poor product accuracy. There was a problem that it deteriorated.

(Object of the Invention) The present invention first pierces a workpiece using a single press die, and then burrs the hole formed by the piercing process as a pilot hole. The purpose is to enable highly accurate machining by performing each machining while being constrained.

(Structure of the Invention) To achieve the above object, the present invention provides a pierce poling punch that separates a pierce processing section for drilling a hole into a workpiece and a burring section having a larger diameter than the pierce processing section. The piercing die is installed to be movable up and down relative to the burring die that performs burring on the workpiece in cooperation with the burring processing section, and the piercing die cooperates with the piercing processing section to make a hole in the workpiece. The piercing die is provided with an elastic body that is installed in the burring die so as to be vertically movable, and that imparts to the piercing die an elastic force strong enough to overcome the force that the piercing die receives through the workpiece due to shearing by the piercing processing section. It is a press type.

(Example) Hereinafter, an example of the present invention shown in FIGS. 2(A) and 2(B) will be described. 1. In FIG. 2, parts that are common to those shown in FIG. 1 are given the same reference numerals.

The pierce burring punch 2 has a pierce processing section 2a for drilling a hole in a workpiece W, and a burring section 2b having a larger diameter than the pierce section 2a, and is attached to an upper holder 4 by a retainer 3. ing. This piercing burring punch 2 is vertically movable by an upper holder 4. A burring die 6 that cooperates with the burring portion 2b of the burring punch 2 is attached to the lower holder 5 fixed below the upper holder 4. A cylindrical piercing die 10, which works together with the processing section 2a to form a hole in the workpiece W, is housed so as to be vertically movable.

This piercing die 10 is provided with an elastic body 13 such as a coil spring between the flange portion 11 and the stepped portion 12 of the lower holder 5, and this elastic body 13 allows the piercing die 10 to move the workpiece W by shearing by the piercing burring punch 2. A resilient force strong enough to overcome the force applied to the piercing die 10 is applied through the piercing die 10, and when the piercing burring punch 2 processes the piercing, the piercing die 10 remains stationary.
A hole is drilled into the workpiece W by cooperation with the piercing section 2a. After drilling, the piercing die 10 is lowered together with the piercing burring punch 2 as the piercing burring punch 2 continues to descend.

Next, the operation will be explained. First, a workpiece W is placed on the burring die 6. At this time, the piercing die 1
Although the top surface of the burring die 6 is located substantially in the same plane as the burring die 6, the upper surface of the burring die 6 may be slightly shifted above the burring die 6. Next, when the upper holder 4 is lowered by a drive source (not shown), the lower surface of the piercing part 2a comes into contact with the workpiece W, and the piercing part 2a and the piercing die 10 work together to produce a shape as shown in FIG. 2(A). A hole is made in the workpiece W. At this time, since the outer side of the hole Wa of the workpiece W is restrained by the piercing die 10, the inner peripheral surface of the hole Wa becomes smooth.

Continuing to lower the piercing burring punch 2,
The piercing die 10 descends together with the punch 2 while restraining the workpiece W, and works together with the burring die 6 to produce the shape shown in FIG. 2(B).
As shown in the figure, a cylindrical burring part wb is formed on the workpiece W. It is also possible to reverse the vertical relationship between the piercing burring punch 2, the piercing die 10, and the burring die 6 in FIGS. 2A and 2B so that the piercing sparring punch 2 is fixed.

(Effects of the Invention) As described above, according to the present invention, a piercing poling punch having a piercing section for drilling a hole in a workpiece and a burring section having a larger diameter than the piercing section is provided.
A piercing die is installed so as to be movable up and down relative to a paring die that performs burring on the workpiece in cooperation with the burring processing section, and that performs burring on the workpiece in cooperation with the piercing processing section. An elastic body is attached to the piercing die so as to be movable up and down in the paring die, and is attached to the piercing die to apply an elastic force strong enough to overcome the force applied to the piercing die through the workpiece due to shearing by the piercing processing section. This makes it possible to perform piercing and burring using the hole formed by this piercing as a pilot hole while the workpiece is held between one press die. Since piercing can be performed while restraining the work, it is possible to form highly accurate piercing and burring portions that do not generate burrs or the like.

[Brief explanation of the drawing]

Figure 1 (A) is a cross-sectional view showing a state in which piercing has been performed using a conventional press mold, and Figure 1 (8) is a cross-sectional view showing a state in which burring has been completed using the press mold in Figure 1 (A). , FIG. 1(C) is a perspective view showing the piercing part and burring part of the workpiece processed by the conventional press mold shown in FIG. FIG. 2(B) is a sectional view showing a state in which piercing is performed using the press die according to the example, and FIG. 2(B) is a sectional view showing a state in which burring is completed from the state in FIG. 2(A). 2... Piercing parring punch, 2a02. Piercing processing part, 2b... Burring processing part, 4... Upper holder, 5... Lower holder, 6... Paring die, 7... Brush holder, 10. ...Piercing die, 13...Elastic body. Patent applicant: Nissan Motor Co., Ltd.

Claims (1)

[Claims] A pierce poling punch having a piercing section for drilling a hole in the workpiece and a burring section having a larger diameter than the piercing section is used to perform burring on the workpiece in cooperation with the burring section. A piercing die is installed in the burring die so as to be movable up and down relative to the burring die, and the piercing die cooperates with the piercing section to make a hole in the workpiece. A press mold in which the piercing die is provided with an elastic body that provides the piercing die with a repulsive force strong enough to overcome the force applied to the piercing die 10 via the workpiece W.