Oil-gas separated pressure cylinder

Abstract

An oil-gas separated pressure cylinder, which combines a hydraulic cylinder, a pneumatic cylinder and a pres-pressure cylinder, and keeps the applied compressed gas and the storage hydraulic fluid apart, maintaining the quality of the hydraulic fluid and saving the hydraulic fluid replacement cost. When the applied compressed gas enters the pre-pressure cylinder to move a pre-pressure cylinder piston in forcing the storage hydraulic fluid out of an oil storage space of the pre-pressure cylinder into an oil storage space in the hydraulic cylinder, a hydraulic cylinder piston of the hydraulic cylinder is then forced by the hydraulic fluid to move a hydraulic cylinder piston rod against the workpiece, and then a pneumatic cylinder piston rod of the pneumatic cylinder is forced into the oil storage space of the hydraulic cylinder to enhance the pressure at the hydraulic cylinder piston rod against the workpiece.

1 . An oil-gas separated pressure cylinder, comprising:
 a hydraulic cylinder comprising a first oil storage space, a hydraulic cylinder piston set in said first oil storage space and a hydraulic cylinder piston rod connected to said hydraulic cylinder piston;   a pneumatic cylinder connected to one end of said hydraulic cylinder, said pneumatic cylinder comprising a pneumatic cylinder piston and a pneumatic cylinder piston rod, said pneumatic cylinder piston rod having one end thereof connected to and movable by said pneumatic piston and an opposite end thereof inserted into said first oil storage space of said hydraulic cylinder; and   a pre-pressure cylinder connected to one side of said hydraulic cylinder, said pre-pressure cylinder comprising a second oil storage space in communication with said first oil storage space, a gas passage in communication with said second oil storage space and a pre-pressure cylinder piston set in said second oil storage space within an output end of said gas passage.   
     
     
         2 . The oil-gas separated pressure cylinder as claimed in  claim 1 , wherein said hydraulic cylinder further comprises a seal member and a spacer, said seal member defining with said hydraulic cylinder piston said first oil storage space, said spacer being set between said seal member and said hydraulic cylinder piston to divide said first oil storage space into an oil storage chamber and a pressure chamber, said oil storage chamber being in communication with said second oil storage space of said pre-pressure cylinder, said pressure chamber having a volume variable with the position of said pneumatic cylinder piston; said pneumatic cylinder piston rod of said pneumatic cylinder is inserted through said seal member into said oil storage chamber and forcible by said pneumatic cylinder piston into said pressure chamber. 
     
     
         3 . The oil-gas separated pressure cylinder as claimed in  claim 1 , wherein said hydraulic cylinder further comprises a first oil guide passage in communication with said first oil storage space; said pre-pressure cylinder further comprises a second oil guide passage in communication with said second oil storage space and said first oil guide passage. 
     
     
         4 . The oil-gas separated pressure cylinder as claimed in  claim 1 , wherein said pre-pressure cylinder further comprises an oil filling tube, said oil filling tube having one end thereof connected to said pre-pressure cylinder piston and an opposite end thereof extending out of said pre-pressure cylinder and terminating in an oil filling hole. 
     
     
         5 . The oil-gas separated pressure cylinder as claimed in  claim 2 , wherein said hydraulic cylinder further comprises a first oil guide passage in communication with said first oil storage space; said pre-pressure cylinder further comprises a second oil guide passage in communication with said second oil storage space and said first oil guide passage.