CS235154B1 - Drawer for deep drawing without blankfolder - Google Patents

Description

(54) Drawbar for deep drawing without retainer

BACKGROUND OF THE INVENTION The present invention relates to a center of gravity for deep drawing of rotary extracts without a retainer.

The invention solves an optimized profile shape of the cavity of the active part of the center of gravity with respect to ensuring tangential contact of the periphery of the flange of the center of gravity with the surface of the center of the center of the center of gravity throughout the deep drawing process.

This effect is achieved by the shape of the active part of the center of gravity being the equidistant of the traction curve distant from it in the normal direction by the value s ₀ (1-K), the traction curve being defined by the differential equation:

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a deep drawing line without a retainer, the active portion of which is circular in shape.

The profiled shapes of the cores used to form the cavity of the center of gravity so far are:

circle, line, quarter,

Huygenss traction and TT2 curve defined by differential equation dy dx y * - (d / 2) ^£ _K (D / 2) ² · - (d / 2) *

1Y ² · - (d, 2) ^Z (D / 2) - lcP / 2 ² ·

in the x, y coordinate system, where the x-axis is identical to the center of gravity and the y-axis lies in the plane of contact of the center line with the center of gravity at the moment of pulling Kz is a function describing the course extract. The application of these curves for the formation of the cavity of the center of gravity was in most cases based on empirical experience, respectively on the limiting conditions and assumptions considered in the calculation of the curve of the cavity of the center of gravity. Generally, the curves do not ensure tangential contact of the circumference of the extract flange in the radial direction with the active surface of the centerline cavity during the entire process of forming the extract by deep drawing. Failure to fulfill the condition in question does not fully exploit the plasticity of the molded material and achieve the maximum possible pulling factor = D / d in one operation.

The shortcomings of addresses and alleviates: die for deep drawing without the hold-down device of the invention, which is characterized in that the profile of the cavity of the die is formed by rotation of a generatrix about an axis of the die, wherein the forming curve of the equidistance tensile curve remote from it in the normal direction by a value of ₀ (K-1.

The drawing curve is described by the end point of the neutral layer of the extract, where the drawing curve is defined by the differential equation

in a orthogonal coordinate system in which the x-axis is identical to the center of gravity and the y-axis lies in the plane of the neutral layer at the time of drawing start where

K - displacement coefficient of the neutral layer with ₀ - thickness of the initial cut b - radius of the plane part of the bottom of the center of gravity R - radius of curvature of the neutral layer of the wall of the center of gravity with the radius R _t . s _o a - radius of the starting circular cut

The die of the invention creates optimal conditions for the formation of real extract ^"HE> X ^{1 +} W ^) e ^t2RtíLrct Ϋ the deep drawn without the hold-down ensures support the periphery of the flange and the tangential contact with the surface of the cavity of the die during the process of deep drawing. This makes it possible to achieve a maximum theoretical ratio of the diameter of the starting blank and the radius of the obtained extract.

An exemplary embodiment of the center of gravity of the invention is shown in the drawing, wherein FIG. 1 is a diagram of a drawing start situation determined by the origin of the coordinate system x, y, and FIG. 2 is a cross-sectional view of a drawing tool for deep drawing.

The profile of the cavity of the center of gravity 7 is formed by the rotation of the forming curve 1 about the x axis 6 of the center of gravity 7. The forming curve 1 is the equidistant of the traction curve 2, distant from it in the normal direction by s ₀ The drag curve 2 is defined by the differential equation:

 in a rectangular coordinate system in which the axis χ B coincides with the axis of the center of gravity 7 and the y axis 8 lies in the plane of the neutral layer 4 at the time of drawing start (Fig. 1). When pulling the extract deep, the flange material in the transition region between the bottom and the walls of the extract 5

S rolls to the radius R of the curvature of the tensile edge of the center of gravity 9, wherein the neutral layer 4 in the bending region around the tensile edge of the center of gravity 9 has a radius of curvature in radial section of the neutral layer 4 R = R _t + K. s ₀ .

Claims (1)

SUBJECT Deep drawing punch without retainer, active part of which is of rotary shape, characterized in that the forming curve (1) is an equidistant of the drawing curve (2) spaced in a normal direction by BACKGROUND OF THE INVENTION s ₀ (1 - K i, the traction curve (2) is described by the end point (3) of the neutral layer (4) of the extract (5), the traction curve (2) being defined by the differential equation: Y = Y '·· a. <b ² -2R ^a , Y 'in a rectangular coordinate system, in which the x-axis (6j is identical to the axis of the center of gravity (7) and the y-axis (8j) lies in the plane of the neutral layer (4) at the moment of drawing. K - displacement coefficient of neutral layer with ₀ - depth of starting blanks b - radius of the plane part of the bottom of the center of gravity R = the radius of curvature of the neutral layer of the extract wall on the tensile edge of the center of gravity (9) with a radius R _t , where R = = R _t + K. s ₀ a - the radius of the starting circular cut-off dy dx 1 sheet of drawings