US 7,066,074 B2Granted

Fluid motor

AssigneeTaiwan Semiconductor Manufacturing Company, Ltd.

InventorsKun-Tzu Lin, Shih-Liang Cheng, Cheng-Chiang Chuang, Chung-Yu Tsai

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Abstract

The piston of a fluid motor divides the cylinder into two variable volumes into which and from which fluid may be selectively introduced and exhausted via ports through the cylinder to relatively move the piston and the cylinder. The piston is modified to define two fixed-volume chambers that respectively communicate with the variable volumes via restrictive orifices. In selected relative piston-cylinder positions, the chambers communicate with the ports to restrict fluid flow into and out of the variable volumes and to decrease the velocity of relative piston-cylinder movement. In other relative piston-cylinder positions, the chambers do not communicate with the ports and fluid enters and leaves the variable volumes directly through the ports to relatively move the piston-cylinder at a higher velocity.

A liner fluid motor having a piston within a close-ended cylinder, wherein the piston, the cylinder sidewall and the cylinder ends divide the cylinder into two variable volumes, the piston and the cylinder being relatively movable between first and second rest positions by selectively introducing a fluid through a first port into one of the variable volumes and simultaneously evacuating fluid through a second port from the other variable volume, comprising:

means carried by and movable with the piston (i) for restricting the introduction of the fluid into the one variable volume while the piston-cylinder is in the first rest position and until there has occurred a selected amount of relative movement out of the first rest position, (ii) for restricting the exhaustion of the fluid from the other variable volume until there can occur a selected amount of relative movement into the second rest position and while the piston-cylinder is in the second rest position, and (iii) for otherwise permitting unrestricted flow of the fluid into or out of the variable volumes to limit the velocity of the relative movement near the end positions, the restricting means including,
seals located on the piston that define between the cylinder and the piston first and second fixed-volume chambers movable with the piston;
and
first and second restrictive orifices, the first orifice interconnecting the first chamber with the first variable volume, the second orifice interconnecting the second chamber with the second variable volume,
the ports and the orifices being so related that, when the end positions are achieved and when the selected amount of relative movement has occurred or can occur, the fluid that is introduced or evacuated into or from the variable volume enters or leaves the associated chamber and thereafter enters or leaves the associated variable volume via the associated restrictive orifice;
and wherein the first and second ports are respectively shaped so that as the fixed-volume chambers move into and out of communication therewith the rate of fluid movement into or out of the chambers changes gradually.

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Abstract

Claims17