Hydraulic device

Abstract

A fluid pressure apparatus is obtained whose installation position is not restricted. The fluid pressure apparatus is provided with a fluid pressure pump ( 1 ) driven by an electric motor ( 6 ) and rotatable in both directions. Both ports of the fluid pressure cylinder are respectively connected to both ports of a fluid pressure pump ( 1 ) through a pair of pipe lines. A sliding cavity ( 38 ) is formed between an outer cylinder ( 32 ) and the inner cylinder ( 34 ), and is divided into a preload chamber ( 50 ) and a tank chamber ( 18 ) by the piston ( 44 ) slidably inserted in the sliding cavity ( 38 ). The tank chamber ( 18 ) and the pair of pipe lines are connected through check valves respectively provided in directions so as to allow discharge from the tank chamber ( 18 ). The tank chamber ( 18 ) is preloaded with air pressure introduced into the preload chamber ( 60 ). In addition, a fluid pressure pump ( 1 ) is disposed in the inner cylinder ( 34 ). The fluid pressure pump ( 1 ) is a swash plate piston pump. The outer cylinder ( 32 ) and the inner cylinder ( 34 ) are arranged coaxially with the rotating shaft 42 of the electric motor ( 6 ). The outer cylinder ( 32 ) and the inner cylinder ( 34 ) are mounted on the electric motor ( 6 ).

1 - 5 . (canceled)  
   
   
       6 . A fluid pressure apparatus provided with a fluid pressure pump driven by an electric motor and rotatable in two directions, both ports of a fluid pressure actuator and both ports of the fluid pressure pump being respectively connected through a pair of pipe lines; 
 wherein a sliding cavity is formed between an outer cylinder and an inner cylinder, and the sliding cavity is divided into a preload chamber and a tank chamber by a piston slidably inserted in the sliding cavity.    the tank chamber and the pair of pipe lines are connected through check valves respectively provided in directions so as to allow discharge from the tank chamber, and the tank chamber is preloaded with the air pressure introduced into the preload chamber;    and the fluid pressure pump is disposed in the inner cylinder.    
   
   
       7 . The fluid pressure apparatus according to  claim 6 , wherein the fluid pressure pump is a swash plate piston pump.  
   
   
       8 . The fluid pressure apparatus according to  claim 6 , wherein the outer cylinder and the inner cylinder are arranged coaxially with a rotating shaft of the electric motor, and the outer cylinder and the inner cylinder are mounted on the electric motor.  
   
   
       9 . The fluid pressure apparatus according to  claim 6 , wherein the tank chamber communicates with the inside of the inner cylinder.  
   
   
       10 . The fluid pressure apparatus according to  claim 6 , wherein a top end of the rotating shaft of the electric motor is rotatably supported by a lid member closing one end of the outer cylinder and one end of the inner cylinder.