| 摘要 |
A linear hydraulic motor includes a piston rod of conventional steel carrying a fragible piston head movable in a cylinder, the head being designed to break away in the event the cylinder wall is punctured and deformed such that a portion of the cylinder wall becomes an obstacle in the path of the piston. Two or more such motors are frequently connected redundantly to one control surface such that if one motor is damaged, the other can continue to perform its function. The piston head is of a brittle metallic matrix material and includes a conventional seal groove formed on its cylindrical surface. Each of the opposite faces of the piston head contains a first deep circumferential groove radially outward from the rod, a second shallower circumferential groove positioned radially outward from the first circumferential groove at essentially the same radial position as the bottom of the seal groove, and a large number of radial grooves effectively dividing the faces into truncated sectors outboard of the deep grooves which can break away.
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