| 摘要 |
<p>A hydraulic actuator provided with a hydraulic pump and a hydraulic cylinder unit. The hydraulic pump has a first suction and discharge opening and a second suction and discharge opening and can be reversely operated. The hydraulic cylinder unit is provided with a piston, a sleeve having an inner space partitioned by the piston into a first pressure chamber and a second pressure chamber, and a piston rod connected to the piston and having a front end projecting to the outside of the sleeve. The hydraulic actuator is provided with first piping for interconnecting the first pressure chamber and the first suction and discharge opening, and also with second piping for interconnecting the second pressure chamber and the second suction and discharge opening. When the hydraulic piston is reversely operated, hydraulic pressure is alternately applied to the first and second pressure chambers to vertically move the piston. The hydraulic actuator is further provided with a bypass pipe for interconnecting the first and second piping and also with an accumulator provided in the middle of the bypass pipe and applying back pressure to the first and second pressure chambers. A vibration test device equipped with the hydraulic actuator is also provided.</p> |
