Patent ID: 7197910
Filing Date: 2007-04-03
Classification: B21D

Abstract:
1. A die cushion apparatus of a press machine, comprising: a die cushion pad which is movable up and down according to a pressurizing force externally applied to the die cushion pad; a first pressure receiving unit comprising a first accommodation unit, a first sliding member and a first hydraulic chamber, the first sliding member being slidably received in the first accommodation unit so as to define the first hydraulic chamber, wherein the first sliding member is caused to slide by a pressurizing force acting upon the die cushion pad to thereby pressurize oil in the first hydraulic chamber; and a second pressure receiving unit comprising a second accommodation unit, a second sliding member, a second hydraulic chamber and a gas pressure chamber, the second sliding member being disposed between the second hydraulic chamber and the gas pressure chamber, only oil pressure and gas pressure acting on the second sliding member, the second sliding member being slidably received in the second accommodation unit so as to define the second hydraulic chamber and the gas pressure chamber, wherein the second sliding member is caused to slide by a pressure of the first hydraulic chamber to thereby compress gas in the gas pressure chamber.