RU1794544C - Die for drawing with extension - Google Patents

Abstract

Usage: in the manufacture of flat parts for cars. The inventive stamp contains clamps, a die and a punch with protrusions at the working end, the outer side wall of the protrusion inclined to the plane of the connector at an angle of 75-80 °, and the inside at an angle of 30-45 °. The height of the protrusion is determined by the calculated dependence. Stamping takes place in two stages: first, the recesses are formed by the protrusions of the punch, followed by stretching of the workpiece, and then stamping between the recesses. 1 s.p. f-ly, 2 ill.

Description

The invention relates to the field of sheet stamping and can be used in mass production in the manufacture of flat parts for passenger cars.

A stretch drawing stamp is known, comprising a punch with protrusions on the periphery of the working end with inclined lateral outer and inner walls (1).

A disadvantage of the known stamp is the impossibility of intensive stretching of the bottom, flat and undeformed parts. This is due to the fact that the bending of the peripheral part of the preform to the formation of a vertical bead occurs when the edge of the preform is not pressed. In addition, the stamp has a large consumption of sheet metal.

The aim of the invention is to save sheet metal and to improve the quality of flat shaped parts.

To achieve this goal, the outer side wall of the protrusion of the punch is inclined to the plane of the die connector at an angle of 75-80 °, and the inside at an angle of 30-45 °. The height of the protrusions is determined from the ratio:

73A-RP-Vm. where A and B are the dimensions of the parts of the working surface of the punch:

B (eP-e Ј1) + (Rn + Pm) (1.73) A 2 --------

RM and Rn are the radii of rounding of the working edges of the matrix and punch;

n (In n / Ј1 - 1) + Ј1 - 1.05 / 0 (1-n / e) ee-d-e

n is the hardening index, fi is the friction coefficient,

10

with

1 o

4

ate

N

4

Ј1 is the deformation of the metal.

In Fig.1 shows a section of the stamp at the time of deformation of the workpiece protrusions of the punch; in FIG. 2 - on an enlarged scale, the node of the protrusions of the punch.

. The stamp consists of the upper and lower halves, which include the clamping rings 1 and 2, the matrix 3, the punch 4 with the protrusions 5.

The stamp works as follows.

The workpiece is laid on the clamping ring 1. When the outer slider of the press moves down, the flange is clamped between the clamping rings 1 and 2.

Then, at the first stage of shaping, the depressions are formed, followed by tension in zones A and B of the workpiece. In zone A, the strains are larger than in zone B and can approach critical values for a given material.

In zone B, the deformations are approximately 50% and should provide a preliminary increase in the surface area of the workpiece necessary to obtain a part of the desired quality.

The strain values in zones A and B depend on the geometry of the tool and the mechanical characteristics of the workpiece material. Key tool parameters

affecting the magnitude and distribution of deformations in the plane of the workpiece are the height H of the protrusions of the workpiece on the punch, the radii of fillet on the matrix and the punch RM and Rn. The angle is 75-80 °. Flat size

The area at the apex of the protrusion is determined by the size of the bent flange and the allowance for trimming and is approximately equal to (30-40) Z0 - the gap between the punch and the die.

The radii of the punch and die are determined as a result of adjustment and are approximately equal to RM (15-10) Z0, Rn (30-50) Z0,, 185. 0.15.

At the second stage, the addition of small depressions takes place.

Improving the quality of parts and saving metal occurs due to increased deformation, rigidity of the part, and a decrease in its thickness. The size of the technological allowance is reduced, which leads to

weight reduction parts.

FORMULA AND SECTION

Claims (2)

1. Stamp for stretch drawing, containing a punch with protrusions on the periphery of the working end with inclined lateral outer and inner walls, a die and upper and lower clamps, characterized in that, in order to save sheet metal and improve the quality of parts gently sloping, the ends are made with flat tops, the outer side wall is inclined to the plane of the die connector at an angle of 75-80 °, and the inside is at an angle of 30-45 °. 2. Stamp pop, 1, characterized in that the height of the protrusions is determined from the ratio 73A-Rn-RM. where A and B are the dimensions of the parts of the working surface of the punch; B (en en ei) + (Rn + RMX1,73 -ZD A2-d1 Jl RM and Rn are the radii of rounding of the edges of the matrix and punch; n (lnn / ci -1) + ei -1.05 / g-O p) her -d-Ј n is the hardening index; fi- coefficient of friction; e is the deformation of the metal.