Invention Grant
US5313872A End of stroke cushion for a linear hydraulic motor 失效
线性液压马达的行程缓冲结束

End of stroke cushion for a linear hydraulic motor
Abstract:
An end of stroke cushion for a linear hydraulic motor. A piston-cylinder unit includes a cylinder body (42) reciprocally slidable on a piston rod (40) having a piston head (64) which defines working chambers (82, 84) within the cylinder body (42). The piston rod (62) is tubular and includes a plurality of sidewall ports (P1-P7). A radially-expandable annular valve ring (106) normally snugly surrounds the piston rod (62) and during axial movement of the cylinder body (42) relative to the piston rod (62), the valve ring (106) will move axially relative to the sidewall ports (P1-P7) in the piston rod (62). Pressure introduction to the working chamber (84) through the sidewall ports (P1-P7) of the piston rod (62) and against the valve ring (106) radially expands the valve ring (106). This allows oil flow to move into the working chamber (84) such that when the chamber (84) expands, the cylinder body (42) and valve ring (106) will move axially relative to the sidewall ports (P1-P7), successively uncovering the ports (P1-P7) during movement. Removal of fluid from the working chamber (84) will cause oil movement out from the chamber (84), through the sidewall ports (P1-P7) into the tubular piston rod (62) such that when the linear motor (10) approaches the end of its stroke, the valve ring will close the sidewall ports (P1-P7) in the piston rod (62) which allows oil flow out from the working chamber (84) in succession.
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