JPH07214193A - Precise sharing die in press machine - Google Patents

Abstract

PURPOSE:To provide a precise shearing die in a press machine, in which the development of breaking surface in the shearing can be reduced in the min. limit without using a special means, by suitably setting the edge of a punch. CONSTITUTION:In the precise shearing die in the press machine for punching by shearing a plate material with the edges 23, 32, 42.of the metallic dies 1, 2 fitted in the press machine and composed of an upper and a lower punched 3, 21 and the dies 4, 22, the cutting edge 31 of one side of either the upper and the lower punches 3 or the dies is composed of the edge 32 having 0.2-0.3mm radius of curvature and the edge surface 33 having 5-15 deg. inclining angle theta and arranged at 0.3-1.0mm width H from the edge 32. This edge surface 33 is desirable to have 0.5-0.7mm width H and 7-10 deg. inclining angle theta.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a die comprising a combination of punches and dies of a press machine for precision shearing.

[0002]

2. Description of the Related Art When precision shearing is performed with a press machine, in order to eliminate sagging, fracture surfaces and burrs that occur on the cut surface of the processed product, the periphery of the plate to be processed is pressed down and a high compressive force is applied to the sheared contour. Punching while operating, or using a die with protrusions to shear about 75% of the plate thickness,
The method of cutting with a knockout tool is adopted.

[0003]

In the conventional precision shearing method, however, the yield of the material is poor because the periphery of the plate material to be processed is pressed down, and the shearing resistance increases so that the required shearing load increases and the required work load. However, there are drawbacks such as low machining efficiency due to increase in the number of tools and the number of tools. An object of the present invention is to provide a precision shearing die for a press machine capable of reducing the occurrence of a fracture surface during shearing to a minimum without employing any special means by appropriately setting the blade edge of the punch.

[0004]

The present invention provides a precision shearing die of a press machine, which is mounted on a press machine, for shearing and punching a plate material at the cutting edge of a tool consisting of a combination of upper and lower punches and dies. One of the upper and lower punches or dies has a radius of curvature of 0.2.
It is characterized by comprising a blade edge having a curvature of ˜0.3 mm and a blade surface provided with a width of 0.3 to 1.0 mm from the blade edge at an inclination angle of 5 to 15 degrees. In the invention according to claim 2, the width of the blade surface is set to 0.5 to 0.7 mm, and the inclination angle is set to 7 to 10 degrees.

[0005]

In the precision shearing die of the press machine according to the present invention, since the clearance between the punch and the die is large at the beginning of shearing, the shearing load may be small, and cracks are generated in this state. If the clearance between the punch and the die becomes smaller, the shearing resistance increases and the required shearing load becomes larger. However, once a crack occurs, cutting can proceed with a smaller shearing force for stress concentration. The sheared surface is secondarily sheared by the tapered blade surface of the die such as a punch and its upper surface. As a result, the sheared surface has few fracture surfaces, and the precision and quality of the press-formed product can be improved.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described with reference to FIGS. FIG. 1 shows a punching work (blanking) die of a press machine, which comprises an upper die 1 and a lower die 2. The upper die 1 comprises an inner diameter punch 3 and an outer diameter die 4 coaxially arranged on the outer circumference of the inner diameter punch 3. The lower die 2 is a cylindrical inner / outer diameter punching punch, and is installed below so as to fit in the annular gap between the punch 3 and the die 4, and the outer circumference has the outer diameter punch 21 and the inner circumference. The die 22 has an inner diameter.

The outer circumference of the lower end of the inner diameter punch 3 is a cutting edge 31, and the cutting edge 31 is composed of a cutting edge 32 and a tapered blade surface 33 continuous with the cutting edge 32. The blade tip 32 has a curvature radius R = 0.25 mm, and the blade surface 33
Is set to have a tilt angle θ = 10 degrees and a width H = 0.6 mm. The inner circumference of the lower end of the outer diameter cutting die 4 is a cutting edge 41, and the cutting edge 41 includes a cutting edge 42 and a tapered blade surface 43 continuous with the cutting edge 42. Radius of curvature R on the cutting edge 42
= 0.25 mm curvature is attached, and the blade surface 43 is
The inclination angle θ is 10 degrees and the width H is set to 0.6 mm. The outer diameter punch 21 and the inner diameter die 22 are
Both are set to a normal right angle.

As shown in FIGS. 2 and 4, a pressure ring 12 connected to a knockout pin 11 is freely displaceable in an annular gap between an inner diameter punch 3 and an outer diameter die 4 of an upper die 1. Is fitted into. Also,
A stripper 25 supported by a spring 24 is attached to the outer periphery of the lower mold 2.

As shown in FIG. 3, in the work of pressing a metal plate (workpiece) 5 to punch it into an annular shape, the upper die 1 descends and abuts against the metal plate 5, and the cutting edges 32, 42 and the cutting edge 23 form a material. To cut into. The shear stress is 32,4
Since the clearance between the blade 2 and the blade tip 23 is initially wide, cutting is performed with a small shearing load, and as the blade tip bites, the side pressure from the side surface of the mold increases and cracks 6 and 7 shown in FIG. When the cracks 6 and 7 enter, the cracks 6 and 7 grow with a smaller force in stress concentration, and the shear load decreases. When the cracks 6 and 7 on both the upper and lower sides are aligned, as shown in FIG.
As shown in FIG. 5, the cutting operation is completed and the annular plate-shaped press-formed product 8 shown in FIG. 5 is formed.

During this shearing process, cracks 6, 7
Occurs toward the other cutting edge, and when the clearance between the cutting edges 32, 42 and the cutting edge 23 is gradually reduced as in the present invention, the crack 6 on the upper side is slightly deflected from the inclined direction to the vertical direction. At the same time, the lateral pressure on the cutting surface of the workpiece during cutting by the cutting edges 32, 42 gradually increases. As a result, the shear surface of the work is burnished on the side of the mold,
The sheared surfaces 81 and 82 of the press-formed product 8 to be punched out are glossy and clean sheared surfaces, and the generation of fracture surfaces is prevented.

In the present invention, the radius of curvature R is 0.2 m.
It is set that m ≦ R ≦ 0.3 mm, the inclination angle θ is 5 ° ≦ θ ≦ 15 °, and the width H is 0.3 mm ≦ H ≦ 1.0 mm. Each numerical limit is below the lower limit, the clearance is too narrow, the effect of reducing the shear load, which is the effect of the present invention, cannot be obtained,
Above the upper limit, the clearance is so large that the reduction of the fracture surface of the sheared surface becomes insufficient. The blade surface 43
Has an inclination angle θ of 7 to 10 degrees and a width H of 0.5 to 0.
When set to 7 mm, the effect of the present invention can be best achieved.

[Brief description of drawings]

FIG. 1 is an enlarged view of a precision shearing die of a press machine according to the present invention.

FIG. 2 is a process drawing of punching by a press machine.

FIG. 3 is an enlarged cross-sectional view of a work being punched by a press machine.

FIG. 4 is a process drawing of punching by a press machine.

FIG. 5 is a perspective view of a press-formed product.

[Explanation of symbols]

 1 Upper Die 2 Lower Die 3 Inner Diameter Punch 4 Outer Diameter Die 5 Metal Plate 6, 7 Crack 8 Press Molded Product 21 Outer Diameter Punch 22 Inner Diameter Die 23, 32, 42 Cutting Edge 31, 41 Cutting Edge 33 , 43 blade

Claims (2)

[Claims] 1. A precision shearing die for a press machine, which is mounted on a press machine to punch a plate material by shear breaking at a cutting edge of a tool consisting of a combination of upper and lower punches and a die, wherein either the upper or lower punch or die is used. One of the cutting blades has a cutting edge having a curvature radius of 0.2 to 0.3 mm and an inclination angle of 5 to 15 degrees with a cutting edge of 0.3 to 0.3 mm.
A precision shearing die for a press machine, comprising a blade surface provided with a width of 1.0 mm. 2. The precision shearing die for a press machine according to claim 1, wherein the blade surface has an inclination angle of 7 to 10 degrees and a width of 0.5 to 0.7 mm.