Method of producing hollow articles by deep drawing
First Claim
1. A method of producing hollow articles by deep drawing, wherein the central portion of a blank positioned on a die is sealingly separated from the blank peripheral portion, said method comprising:
- (a) providing a rigid punch to act against one face of the blank central portion;
(b) pressurizing the other face of the blank central portion with a first high pressure fluid from a first high pressure fluid source;
(c) pressurizing the peripheral portion of the blank with a second high pressure fluid from a second high pressure fluid source;
(d) providing pressure intensifying means to selectively intensify the second high pressure fluid acting on the peripheral portion of the blank;
(e) providing a linearly movable cam having a predetermined cam profile for regulating the pressure intensifying means;
(f) regulating the pressure intensifying means so that the second high pressure fluid acts on the blank peripheral portion at a predetermined pressure level in cooperation with the operation of the punch;
(g) sensing the linear position of the cam to regulate the fluid pressure q acting on the blank peripheral portion in accordance with the following law;
##EQU4## where β
is the coefficient accounting for the influence of an average main stress of the blank material;
σ
s is the yield stress of the blank material;
Ri is the blank running radius;
Ro is the punch radius;
t is the wall-thickness of a finished product;
σ
1 is the stress on the inner edge of the peripheral portion of a blank.
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Abstract
A press for manufacturing hollow articles by deep drawing comprising a high pressure vessel (1) accommodating a die (3) with a punch (4). A blank (14) is accommodated in an annular high pressure chamber (16) communicating with a high pressure chamber (19) of an intensifier (20). The press also comprises a device (27) for regulating pressure in the annular chamber to control pressure acting upon the peripheral portion of a blank in accordance with a preset law, an appliance (39) for setting pressure in the annular chamber is made in the form of a tracer whose profile is equidistant with the curve characterizing the alteration of pressure in the annular chamber (16).
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Citations
1 Claim
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1. A method of producing hollow articles by deep drawing, wherein the central portion of a blank positioned on a die is sealingly separated from the blank peripheral portion, said method comprising:
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(a) providing a rigid punch to act against one face of the blank central portion; (b) pressurizing the other face of the blank central portion with a first high pressure fluid from a first high pressure fluid source; (c) pressurizing the peripheral portion of the blank with a second high pressure fluid from a second high pressure fluid source; (d) providing pressure intensifying means to selectively intensify the second high pressure fluid acting on the peripheral portion of the blank; (e) providing a linearly movable cam having a predetermined cam profile for regulating the pressure intensifying means; (f) regulating the pressure intensifying means so that the second high pressure fluid acts on the blank peripheral portion at a predetermined pressure level in cooperation with the operation of the punch; (g) sensing the linear position of the cam to regulate the fluid pressure q acting on the blank peripheral portion in accordance with the following law;
##EQU4## where β
is the coefficient accounting for the influence of an average main stress of the blank material;σ
s is the yield stress of the blank material;Ri is the blank running radius; Ro is the punch radius; t is the wall-thickness of a finished product; σ
1 is the stress on the inner edge of the peripheral portion of a blank.
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Specification