RU1584221C - Die for sheet pressing - Google Patents

Abstract

FIELD: mechanical working of metal. SUBSTANCE: die has plunger die, mould, unit for pressing a blank and braking members made of projections and hollows and arranged on the pressing unit and mould perpendicular to contour of its working opening. Brake members are rectangular, triangle or trapezium in plane and are rectangular and has side perpendicular to the pressing surfaces of the pressing unit and mould in plane parallel to axis of the die. The number of brake members depends on a force of tightening, thinness of material to be worked, periphery of mating surfaces of the members, and space between the surfaces. Braking of the blank face is performed owing to rigid prism-like members provided on it. EFFECT: decreased metal usage. 3 cl, 6 dwg

Description

 The invention relates to the processing of metals by pressure, and in particular to tooling for sheet stamping by hood.

 The aim of the invention is to save metal during stamping with tension by eliminating the movement of the flange of the workpiece during stamping.

 In FIG. 1 schematically shows the proposed stamp, General view; in FIG. 2 - matrix, plan view; in FIG. 3 is a section AA in FIG. 1; in FIG. 4 - an element of the flange of the sheet stock with molded protrusions and depressions of a rectangular shape, plan view; in FIG. 5 - part of the flange of the workpiece with protrusions and depressions of a triangular shape, plan view; in FIG. 6 - the same, but trapezoidal, plan view.

 The stamp for sheet stamping contains a punch 1, a matrix 2 with recesses 3, a clamp 4 with brake elements in the form of protrusions 5.

 The stamp for sheet stamping can be installed on double and simple presses. In the latter case, the recesses 3 are performed on the lower clip operating from a pneumatic press pad (not shown in FIG.).

 The stamp works as follows.

 The sheet blank 6 is laid on the matrix 2. The clamp 4 is lowered. The protrusions 5 act on the flange of the blank 6, deform the material and enter the recesses 3 of the matrix 2, stamping. Then lower the punch 1, which is the plastic deformation of the workpiece 6 to obtain the finished part. During the process of forming parts, the flange of the workpiece 6 is in a fixed stationary state, sandwiched between the recesses 3 and the protrusions 5.

Prismatic elements stamped on the flange represent rigid structures. The efforts of plastic deformation during the extraction of products cause along the lines of conjugation of the vertical surface of the brake elements with the horizontal surface of the clamp and the shear stress matrix. The conditions for complete braking of the material without its destruction on the flange are possible provided
P _det <n LS σ _cf , (1) where P _det is the force required to shape the workpiece (determined from the reference literature on sheet stamping);
n is the number of stampings on the flange of the workpiece;
L is the perimeter in terms of one stamping;
S is the thickness of the material;
σ _cf - shear resistance for a given material, kgf / mm ² .

, , (2) где а - сторона выштамповки детали.The size of the workpiece is determined by the location of the brake elements relative to the contour of the working hole of the matrix and depends on the resistance of its working edge. It has been experimentally established that the minimum distance mentioned must be at least 8 mm. The minimum flange size also depends on the thickness of the stamped material and the drawing force and can be determined as follows:
L = 3a; a = 8 +

,, (2) where a is the side of the stamping part.

 The punching height was determined empirically, it was not less than 3 mm, at this height the material braking conditions are met.

 An experimental stamp was made in the press industry for sheet stamping of parts of a VAZ-2108 "Bonnet Panel". Experimental tests were carried out, at which the optimal values proposed above were obtained: the depth of the stampings, the distance from the braking elements to the distance of the working hole of the matrix.

 The proposed design of the stamp gives the greatest effect when drawing parts with a slight curvature of the surface. In addition to the economical use of material, an improvement in the quality of the surface of parts during stamping is achieved, which is most important for body parts in the automotive industry. The use of dies of this design on presses of simple and double action allows you to effectively use existing equipment without additional capital investments.

Claims (3)

 1. A STAMP FOR SHEET STAMPING, comprising a punch, a die with recesses on the periphery of its clamping surface and a clamp with brake elements in the form of protrusions on the periphery of its working surface included in the recesses of the matrix, while the brake elements have a profile that is equidistant to the profile of the recesses of the matrix, and arranged normal to the contour of the working hole of the matrix, characterized in that, in order to save metal during stamping with tension due to the exclusion of movement of the workpiece flange during stamping, protrusions and depressions in the plane, steam allele axis of the stamp, have a rectangular shape with sides that are perpendicular to the clamping surfaces of the matrix and clamp.  2. The stamp according to claim 1, characterized in that the protrusions and depressions are triangular in shape.  3. The stamp according to claim 1, characterized in that the protrusions and depressions in the plan have the shape of a trapezoid.

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