JP2005199343A - Floating punch - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the shape of the section of a product by performing press working at a high speed. <P>SOLUTION: The structure of a press die is performing such that a punching portion floats inside a cope. When the cope descends, the punch moves downward from the medium point of a stroke at the maximum speed of the stroke and touches a workpiece so that press working is performed at the high speed. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

Detailed Description of the Invention

Technical field belonging to the invention

The present invention relates to a structure of a light-load press die used for punching and forming a thin plate.

In the structure of the press die, a punch and a stripper are arranged on the upper die, and the punch is attached to the punch plate and fixed to the upper die set. The stripper is attached to the upper die set via a spring. The die is attached and fixed to the lower die plate. During operation, the upper die is attached to the ram of the press and repeatedly moves up and down by the movement of the press ram. In punching with a punch, the processing speed is determined by the motion curve of the press ram. Since the press ram is driven by an eccentric shaft and a crankshaft, generally, when punching with a sine curve or the like, the punch is slowly decelerated and punched slowly.

Problems to be solved by the invention

Since the punching speed is slow, the sheared surface of the punched product has a large sag and curvature, and the fracture surface length is long.

Means to solve the problem

A space is provided between the stripper and the die set upper mold in the upper mold of the mold, and the punch portion is inserted. The punch part is composed of a punch, a punch plate, and a backing plate.

The punch portion moves freely when the upper die moves up and down in the space in the upper die.

When the upper mold attached to the ram descends from the top dead center due to continuous vertical movement of the ram, the speed gradually increases, reaches the highest speed at the midpoint of the stroke, and gradually decelerates toward the bottom dead center. To reach bottom dead center. When performing the punching process, the stripper holds the workpiece near the bottom dead center, and then the punch pulls the workpiece.

When the upper die decreases in speed from the maximum speed when descending, the floating punch moves in the upper die, and gravity is added from the maximum speed to increase the speed and punch the workpiece. At this time, the idle punch is set so that the stripper falls while the workpiece is being pressed and is punched.

In the upper mold configuration, the punch 1 is fixed to the punch plate 2, and the backing plate 4 is fixed to the back surface of the punch to form a punch portion. The punch 1, the punch plate 2, and the backing plate 4 can be integrated into one or two parts.

The stripper 3 is suspended from the die set upper die 5 and pressurizes the workpiece 10 through a spring 6 during punching, and has a function of extracting a scrap portion of the workpiece 10 from the punch 1 after punching. The stripper 3 can be fixed to the lower mold.

The punch portion is in the middle of the stripper 3 and the die set upper die 5 and has a structure that can be hung on the die set upper die 5 by a suspension bolt 7 or a block that replaces the die set upper die 5 and move freely with a constant stroke ho.

In the lower mold, the die 8 is fixed to the die set 9. The die 8 can also be fixed to the die set 9 via a support part in the middle of a die plate or the like. The workpiece 10 is fed above the die 8.

FIG. 1 shows the time when the upper die composed of the punch portion attached to the press ram, the stripper 3 and the die set upper die 5 arrives at the top dead center. When the upper die moves upward, when the upper die moves upward and reaches the top dead center, the upper die stops, but the punch portion still moves upward due to inertia, and a part of the punch portion, FIG. Then, the backing plate 4 stops moving by the die set upper mold 5.

At this time, an interval h3 is formed between the punch plate 2 and the stripper 3 by adding a deflection allowance of the stripper spring 6 that presses the workpiece 10 of the stripper 3 to the punch portion free stroke ho.

When the upper die is moved downward by the ram and the stripper 3 is in contact with the workpiece 10, the punch portion is moving downward between the stripper 3 and the die set upper die 5 and the upper portion of the punch portion and the die set A space h <b> 1 is formed between the molds 5 and a space h <b> 2 is formed between the punch portion and the stripper 3. (Figure 2)

When the die set upper mold reaches the vicinity of the bottom dead center, the punch portion is moved downward, and the workpiece 10 is punched out by the punch 1 to be processed. At this time, an interval h0 corresponding to an idle stroke is generated between the punch portion and the die set upper die 5. (Figure 3)

FIG. 4 shows a stroke h / time t diagram showing the vertical movement of the upper die. The upper die descends with time from the top dead center T along the upper die motion diagram, reaches the maximum speed at the intermediate point M, and then gradually. The speed is reduced to zero at the bottom dead center B, and the speed is increased to the next top dead center at a distance of S.

The stripper 3 comes into contact with the workpiece 10 at a point S, which is a distance a before the bottom dead center, stops its movement, and the stripper spring is bent to apply pressure to the workpiece by lowering the upper die. When the upper die rises after passing through the bottom dead center B, the deflection of the spring is recovered and the pressure on the workpiece is reduced. At the point S ′, the pressure becomes zero, and the wrist clipper 3 is integrated with the upper die as follows. Head to top dead center.

During continuous operation, the punch part is located above the upper die at the top dead center by the idle stroke ho. However, when machining, the punch part moves down integrally with the upper die and reaches the maximum speed at the intermediate point M. The punch is accelerated by the acceleration of gravity acting on the punch portion, and the punch comes into contact with the workpiece 10 near the bottom dead center to perform punching. When the punch part leaves the die set upper mold 5, it is possible to increase the speed further by giving an initial speed with a spring or the like.
A processing speed can be adjusted by arranging a spring or the like between the stripper 3 and the punch portion.

The floating stroke ho is determined so that the timing at which the punch 1 passes through the stripper 3 and contacts the workpiece can be set between the point S at which the stripper 3 stops and S ′ at which the stripper 3 starts to rise again. The positions of the points S and S ′ indicate the lower surface of the stripper 3, that is, the upper surface of the workpiece 10.

Stopping of the stripper 3 located at a distance a from the bottom dead center B of the stroke axis h, that is, the point S where the workpiece starts to be pressurized, and the stripper 3 starts rising again, that is, the pressure applied to the workpiece becomes zero. Times from the origin 0 of the time axis at the point S ′ are set as ts and ts ′, respectively. The processing conditions suitable for this processing are as follows, where p is the intersection of the punch motion curve and SS ′ indicating the stop of the stripper 3 and tp is the time from the time axis O of the p point.
ts <tp <ts ′

As means for applying pressure to the floating punch, a block that moves freely with respect to the upper die upper part or the press ram can be provided on the upper die upper part or the press ram side, and the force can be transmitted to the punch through a pin or the like.

Invention effect

Since the present invention is configured as described above, the following effects are obtained.

By punching at high speed, the shape of the shear surface of the product is improved.

The main improvement is that anyone who encounters the first punch on the shear surface will be reduced. The warpage of the punched product is improved. Generation of cracks on the shear surface can be suppressed.

The state of the vicinity of the top dead center is shown in the mold sectional view of the present invention. The die sectional view of the present invention shows a state before punching near the bottom dead center. In the die sectional view of the present invention, a state immediately after punching is shown at the bottom dead center. The movement curve of the floating punch in the metal mold | die of this invention is shown.

Explanation of symbols

1 Punch 2 Punch Plate 3 Stripper 4 Backing Plate 5 Die Set Upper Die 6 Spring 7 Hanging Bolt 8 Die 9 Die Set Lower Die 10 Workpiece

Claims (2)

A mold having a structure in which a punch portion is arranged between the stripper 3 and the die set upper die in the upper die so that the punch portion can move freely. Die having a structure in which the punching speed is set at the middle point of the upper mold or higher.

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