JPH06102239B2 - Extruding punch centering device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION "Industrial field of application" The present invention relates to an extrusion forging die having a punch having a bearing land having a diameter slightly larger than that of a punch shank portion at a tip portion thereof. The present invention relates to a centering device for an extrusion punch that does not limit the thickness.

“Prior Art” Conventionally, a die for extrusion forging is, as shown in FIG.
The upper die 1 attached to the slide side of the press is provided with a punch 2 having a bearing land having a diameter slightly larger than the punch shank portion at the tip portion, and the lower die 3 attached to the bed side of the press is provided with a die 4 and a counter punch 5. The punch 2 is guided by a split stripper guide bush 7 having a shank portion provided on a stripper plate 6, and the stripper guide bush is pushed down by a piston 8 as shown on the right side of the drawing when the punch 2 descends. The punch 2 is fitted into the die 4 to center the punch 2, and when the punch 2 is lifted up, the bearing land at the tip of the punch 2 is drawn into the recess provided in the lower surface of the stripper guide bush 7 as shown on the left side of the drawing, and the punch after processing is punched. It was designed to act as a stripper for removing the product 9 attached to 2 and rising from the punch 2. The stripper plate 6 is movable up and down by the lower mold 3 and is biased upward so that the upper limit is restricted.

[Problems to be Solved by the Invention] In the above-described conventional apparatus, the stripper guide bush 7 centers the punch 2 during processing of the product 9 and the upper limit of the stripper guide bush 7 adheres to the punch 2 to raise the product. In order to remove 9 from the punch 2, it is necessary to pull in the bearing land at the tip of the punch 2. The upper limit of the stripper guide bush 7 is regulated by the stripper plate 6, and since the total length is also limited, the depth of the recess provided on the lower surface is also limited. Therefore, the stroke length of the press slide is limited to the depth of the recess. Furthermore, when the punch 2 is sucked by the load during processing (becomes thick and contracts in length), the ascending punch 2 forcibly pulls up the stripper guide bush 7 and damages the stripper plate 6, and There was a defect such as the stripper guide bush seizing.

An object of the present invention is to provide a centering device for an extruded punch which is not limited by the stroke length of a slide of a press and does not damage the stripper plate even when the punch is scooped, except for these drawbacks. .

"Means and Actions for Solving Problems" According to the configuration of the present invention, the upper die is provided with a punch having a bearing land at the tip portion, the lower die is provided with a die and a counter punch, and the shank portion of the upper punch is provided. By providing a guide bush that is slidable and urged downwards, it is fitted on the stripper plate at the top of the die during processing and the guide bush is fitted, and a stripper bush having a hole through which the punch passes through with a slight gap is provided. Cylinder that performs centering of the punch, regulates the upper limit by vertically moving the stripper plate to the lower mold and urges it upward, and presses the stripper plate on the upper mold when the punch descends to insert the stripper bush into the die. Is provided.

Therefore, when the punch rises, the guide bush engages with the bearing land of the punch and is pulled up to separate from the stripper bush.Therefore, damage such as bending of the stripper plate does not occur. Removed by stripper bush at the upper limit,
Since the punch can pass through the stripper bush and rise, the stroke length of the slide is not limited.

[Embodiment] FIG. 1 shows the structure of a die provided with a centering device for an extrusion punch according to the present invention. A punch 11 having a bearing land slightly larger in diameter than the shank portion is fixedly mounted on the upper die 10 fixed to the slide side of the press, and a split guide bush 12 is ringed on the shank portion of the punch 11. A guide bush 12 press-fitted into 13 is provided slidably. The guide bush 12 is urged downward by the spring 14 and is mounted on the upper die 10 so as to be vertically movable.
In the state shown on the left side of the drawing in which the upper die 10 is being urged downward by the upper die 10, the punch 11 is pushed down to a position where it abuts on the bearing land of the punch 11. The upper mold 10 is provided with a cylinder 16 for pushing down the stripper plate described later,
The piston 17 of the cylinder 16 is urged downward by pressurized air.

The lower die 18 fixed to the bed side of the press is provided with a die 21 and a counter punch 22 that cooperate with the punch 11 to extrude the material 19 into the product 20. Below the counter punch 22, a knockout pin 23 for pushing up the counter punch 22 and taking it out from the die 21 after the product 20 is processed is provided.

Above the die 21, a stripper plate 25 is provided on the outer peripheral portion of the lower die 18 so as to be vertically erected on a required number of guide rods 24, and is urged upward by a spring 26 so that the upper limit is the head of the guide rod 24. It is regulated at 24A. A stripper bush 27 is provided at the center of the stripper plate 25. When the outer periphery of the lower part of the stripper bush 27 descends, it slides into the center hole 28A of the guide 28 fixed to the upper surface of the die 21, and on the upper surface of the stripper bush 27, the outer periphery of the ring 3 of the guide bush 12 that descends slides into a recess. A hole 27A is provided so that the bearing land of the punch 11 can pass through with a slight gap even when the punch 11 is scooped during processing between the recessed hole 27A and the lower surface.
27B is provided. The ring 13 is provided with a flange 13A that determines the depth of fitting into the recess 27A.

As shown on the left side of the figure, the die 21
Supply material 19 to. Next, when the upper die 10 descends, the piston 17 of the cylinder 16 pushes down the stripper plate 25, and the stripper bush 27 is slid into the center hole 28A of the guide 28. The guide bush 12 descending together with the punch 11 is urged by the pin 15 and the spring 14 to slide the ring 13 into the concave hole 27A of the stripper bush 27, and when the fitting depth is determined by the flange 13A, the pin 15 is retracted thereafter. . The punch 11 passes through the hole 27B of the stripper bush 27 and descends, and the upper die 1
At the lower limit of 0, the state shown on the right side of the figure is reached, and material 19 is
Extrude to 0.

When the upper die 10 rises, the product 20 is pushed up by the knockout pin 23 and rises together with the punch 11, and when the stripper plate 25 stops at the upper limit, the punch 11 passes through the stripper bush 27 and rises. At this time, the product 20 comes into contact with the stripper bush 27 and separates from the punch 11. Subsequently, the bearing land of the punch 11 comes into contact with the guide bush 12, and the guide bush 12 is lifted together with the punch 11 and separated from the stripper bush 27. If the punch 11 is scooped during processing, the shank portion of the punch 11 becomes thick and cannot slide with the inner diameter of the guide bush 12. Then, as the punch 11 rises, the guide bush 12 also rises, and when the stripper plate 25 stops at the upper limit, the guide bush 12 comes out of the stripper bush 27. Subsequently, when the punch 11 passes through the stripper bush 27 and rises, the product 20 comes into contact with the stripper bush 27 and separates from the punch 11.
If punch 11 is scraped by a process that is practically normal, punch 11
Even if the shank portion is thick and the inner diameter of the guide bush 12 is enlarged, the outer diameter of the ring 13 fixed integrally with the guide bush 12 is not enlarged so much that it cannot slide with respect to the inner diameter of the stripper bush 27. Therefore, the stripper plate 25 is not damaged, and damage to the lower die such as bending of the lower guide rod 24 due to damage to the stripper plate 25 can be prevented.

[Advantages of the Invention] As is apparent from the above effects, according to the present invention, since the guide bush of the punch and the stripper bush are separated, there is no limitation on the stroke length of the slide, and the stripper plate is not damaged. , The practical effects and advantages are great.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view of an essential part of a press die of an embodiment, and FIG. 2 is a longitudinal sectional view of an essential part of a conventional press die. 1 is an upper die, 2 is a punch, 3 is a lower die, 4 is a die, 5 is a counter punch, 6 is a stripper plate, 7 is a stripper guide bush, 8 is a piston, 9 is a product, 10 is an upper die,
11 is a punch, 12 is a guide bush, 13 is a ring, 13A is a flange, 14 is a spring, 15 is a pin, 16 is a cylinder,
17 is piston, 18 is lower mold, 19 is material, 20 is product, 21 is die, 22 is counter punch, 23 is knockout pin, 24 is guide rod, 24A is head, 25 is stripper plate, 2
6 is a spring, 27 is a stripper bush, 27A is a concave hole, 27B is a hole, 28 is a guide, and 28A is a central hole.

Claims (1)

[Claims] 1. A punch (1) comprising an upper punch (11) having a bearing land at its tip and a die for extrusion press working with a lower die (21) and a counter punch (22).
In the device for centering 1), the guide bush (12) is slidable on the shank part of the punch (11), is retained by the bearing land, and is biased downward, and the lower stripper plate (25). Is pressed down by the upper mold piston (17) that is urged downward, and its outer periphery slides into the center hole (28A) on the upper surface of the die (21) and the concave hole (27A) on the upper surface. A centering device for an extrusion punch, comprising: a guide bush (12) and a stripper bush (27) having a hole (27B) through which the punch (11) is slid.