RU2060075C1 - Deep drawing die - Google Patents

Abstract

FIELD: deep drawing of hollow sheet parts. SUBSTANCE: die set for deep drawing of sheet parts includes a lower die, a punch and a clamping ring, secured with the aid of a slit ring and bolts to an annular rest. A working surface of the clamping ring at drawing process engages with a flange of a blank, being drawn, that is why the clamping ring is in the form of an elastically deformable ring, secured to a drive unit for it motion along a circular area with an axis of a circle. A thickness of a ripple holder is selected according to a relation, given in a description of the invention. EFFECT: enhanced quality of drawn sheet parts, made by such method. 1 cl, 3 dwg

Description

 The invention relates to the processing of metals by pressure and can be used in various industries in the manufacture of hollow sheet parts.

 A stamp for deep drawing is known, containing a coaxial punch installed and covering the matrix and the clamp, the latter being made in the form of an elastic metal clamping ring mounted on an external press slide and arranged coaxially and in contact with it an annular stop, the diameter of the protruding part of which is equal to the diameter of the exhaust coupling the edges of the matrix with its flat surface.

 The use of this stamp, providing high quality and wide technological capabilities of the parts to be drawn, is associated with the high cost of its manufacture due to the complexity of the design of the elastic element in the pressure ring.

 The technical problem solved by using the proposed stamp for deep drawing, is that it is very simple to manufacture and at the same time provides high-quality manufacturing of sheet parts while maintaining wide technological capabilities.

где d диаметр пуансона, мм;
D_о наружный диаметр упругого прижимного кольца, мм;
σ_в- предел прочности вытягиваемого материала, кгс/мм²;
E модуль упругости материала упругого прижимного кольца.In the stamp for deep drawing, containing the coaxially mounted punch and covering its matrix and clamp, the last of which is made in the form of an elastic metal clamping ring mounted on the external press ram and placed coaxially and in contact with it an annular stop, the diameter of the protruding part of which is equal to the diameter of the mating drawing edge of the matrix with its flat surface, the thickness of the elastic clamping ring is made constant in the radial direction and is determined from the ratio:
H 0.24 / 5.5d + D _o /

where d is the diameter of the punch, mm;
D _{about the} outer diameter of the elastic clamping ring, mm;
σ _in - tensile strength of the material being drawn, kgf / mm ² ;
E is the modulus of elasticity of the material of the elastic pressure ring.

 In FIG. 1 shows a cross section along the plane of symmetry in the position before the start of the drawing of the part and at the intermediate moment of drawing the part (the clamping ring is unloaded); in FIG. 2 the same, at the intermediate moment of drawing the part (with a loaded clamping ring) and at the end of the drawing of the part; in FIG. 3 diagram of the loading of the clamping ring.

 The stamp contains an exhaust matrix 2 mounted on the press table 1, an elastic clamping ring 3, attached by means of a split ring 4 and bolts to the annular stop 5, a punch 6 mounted on the press slider.

 The stamp works as follows.

 In the initial position of the stamp, the stop 5 with the clamping ring 3 and the punch 6 are in the highest position, which allows you to set and center the workpiece on the die 2. Turning on the press stroke first leads to lowering the clamping ring 3 until it comes into contact with the workpiece 7 to create a clamping force.

P _ave = 0.3P _W. = 0.3π · d · S · σ _in (1) where P _{w is the} force on the punch required to draw the part;
d punch diameter;
S is the thickness of the drawn blank;
σ _{to the} tensile strength of the stamped material of the part.

 After that, the lowering punch 6 first comes into contact with the workpiece 7 (see Fig. 1), and then carries out its shaping in the exhaust matrix 2 in the semi-finished products 8 and 9 (see Fig. 1 and 2) and in the product 10 (see Fig. 2). When the punch 6 reaches its lowest position (see Fig. 2), the press moves backward, in which the pressure ring 3 and the punch 6 are raised to their highest position, the stamped product 10 is removed from the punch 6 and removed from the die working area.

= S/D_о·0,01).The hood of the flat workpiece 7 into the hollow part 10 is accompanied by a thickening of its flange part, with the greatest thickening taking place on the outer edge of the workpiece. The diameter D _t in FIG. 1 conventionally shows what would have happened if the hood were drawn in a conventional exhaust dies with the clamping ring 3 fastened over its entire reverse surface to the drive of its movement. This leads to the fact that the flange part of the workpiece in the annular zone, determined by the diameter D _t and D _p , is not pressed by the clamping ring 3, which leads to folding of the stamped material of small relative thickness (

= S / D _o · 0.01).

The use of the proposed stamp with a clamping ring 3 made of hardened steel (elastic modulus E = 2.1 · 10 ⁴ kgf / mm ² with its fastening to the stop 5 along an annular platform with a circular axis with a diameter of D = d + 2r _μ (where r _{μ is the} radius of the extrusion edge of the matrix 2), leads to the formation of a slightly curved surface of double curvature, which is called an elastic surface, and the shape of this surface is characterized by the law of variation of the deflection of the plate.

(b²-a²) +

ln²

(2) или с учетом значения P_пр, по формуле (1) и принятого обозначения K= b/a, получаем
ω

(K²-1) +

ln²K

(3)
Значение толщины S на наружной кромке фланца заготовки устанавливается согласно известной зависимости.In FIG. 3 shows a design diagram of a clamping ring loaded along the inner contour with distributed clamping forces P _CR , according to which the deflection of the clamping ring ω at the inner edge of the flange at (a = d) is
ω

(b ² -a ² ) +

ln ²

(2) or taking into account the value of P _ol , according to formula (1) and the accepted notation K = b / a, we obtain
ω

(K ² -1) +

ln ² K

(3)
The thickness value S at the outer edge of the workpiece flange is set according to a known relationship.

S

(4)
Очевидно, что прогиб ω прижимного кольца 3 должен соответствовать максимальному утолщению фланца заготовки при вытяжке, величина которого при вытяжке устанавливается по формуле:
ω S-S_o=S_o(

-1)
(5)
Подстановка значений прогиба ω согласно формуле (2), μ=0,3 в формулу (3) и решение полученного уравнения относительно H/a приводит к зависимости, представленной в виде:

^{= 0,3(5,5+K),}
в результате чего формула (5) перепишется следующим образом:
H 0,24 (5,5d +D_o)

(6)
Таким образом, толщина прижимного кольца 3 в предложенном штампе зависит от геометрических параметров его формообразующих элементов (d и D_о) от предела прочности штампуемого материала (σ_в) и от модуля упругости материала прижимного кольца Е.SS _o

S

(4)
Obviously, the deflection ω of the clamping ring 3 must correspond to the maximum thickening of the workpiece flange during the hood, the value of which during hood is set by the formula:
ω SS _o = S _o (

-1)
(5)
Substitution of the values of the deflection ω according to the formula (2), μ = 0.3 in the formula (3) and the solution of the obtained equation with respect to H / a leads to the dependence presented in the form:

^{= 0.3 (5.5 + K),}
as a result, formula (5) is rewritten as follows:
H 0.24 (5.5d + D _o )

(6)
Thus, the thickness of the clamping ring 3 in the proposed stamp depends on the geometric parameters of its forming elements (d and D _о ) on the tensile strength of the stamped material (σ _in ) and the elastic modulus of the material of the clamping ring E.

Claims (1)

A stamp for deep drawing, containing a coaxially mounted punch and covering its matrix and clamp, the latter being made in the form of an elastic metal clamping ring mounted on the external press slide and arranged coaxially and in contact with it an annular stop, the diameter of the protruding part of which is equal to the diameter of the mating lip matrix with its flat surface, characterized in that the thickness of the elastic clamping ring is made constant in the radial direction and is determined from the ratio

where H is the thickness of the elastic pressure ring;
d diameter of the punch, mm;
D _{about the} outer diameter of the elastic clamping ring, mm;
σ _{to the} tensile strength of the material being drawn, kgf / mm ² ;
E is the modulus of elasticity of the material of the elastic pressure ring.

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