| 摘要 |
<p>There is provided a vibration generating apparatus, which comprises: a cylinder assembly (6) having a cylinder and a piston (3) slidably inserted in a cylindrical bore (2) of the cylinder for defining a first pressure receiving chamber (4) with a small pressure receiving area and a second pressure receiving chamber (5) with a large pressure receiving area, the piston (5) being movable in one direction with a pressure fluid within the said first pressure receiving chamber and in the other direction under a difference in pressure based on a difference in pressure receiving area between the said first pressure receiving chamber and the said second pressure receiving chamber; a switching valve (9) having a first pressure chamber (13) with a large diameter, a second pressure chamber (14) with a small diameter, a pump port (10), an auxiliary port (23), a principal port (11) and a tank port (12) and being adapted to take a first position under a pressure within the said first pressure chamber and to take a second position under a pressure within the said second pressure chamber, the said first position being taken to allow the said pump port to communicate with the said auxiliary port and to allow the said principal port to communicate with the said tank port, the said second position being taken to allow the said pump port to communicate with the said principal port and to allow the said auxiliary port to communicate with the said tank port; and a servo valve (19) responsive to a movement of the said piston for establishing a communication of the said pressure chamber with a fluid pressure source (21) or a tank, each of the said first pressure receiving chamber and the said second pressure chamber having a communication with the said fluid pressure source, the said second pressure receiving chamber having a communication with the said principal port. <IMAGE></p> |
