To provide a pressure generating device for reducing the changing frequency of a seal.
The pressure generating device increases hydraulic pressure in a hydraulic pressure chamber 4 in a cylinder 1 with a rod 2 slid and pushed into the cylinder 1. The seal 7 is arranged at the end of the cylinder for sealing a gap between the inner periphery face of the cylinder and the outer periphery face of the rod, and a drain part 8 is provided on the side of the hydraulic pressure chamber beyond a seal arranged area for draining oil between the inner periphery face of the cylinder and the outer periphery face of the rod to the outside. An oil resupply hole 21 is provided at the end of the cylinder at the side of the hydraulic pressure chamber for supplying oil into the hydraulic pressure chamber. An oil supply source 22 is connected to the oil resupply hole via a pressure control valve 23, a throttle valve 24 and a check valve 25.
Yasuo Asami
Yoshitaka Takeyama
Takamori Suzuki