| 摘要 |
<p>A piston shoe (10) of an axial piston pump or motor is crimped to an annular piston head (42) and has a flat shoe wear surface (12) that contacts a cam plate (22). A back flange (14) of the shoe (10) also wears against an auxilliary cam plate (24). In order for the piston shoe (10) to operate within a fuel environment, the piston shoe (10) must be corrosion resistant, compatible with fuel, and provide the desired wear resistance. The piston shoe (10) is made of a cold workable cobalt based alloy which is compatible with fuel and provides corrosion resistance. The wear surface (12) which bears against the cam plate (22) and the back flange (14) which bears against the auxilliary cam plate (24) are provided with a thermal diffusion boride treatment which provides the desired wear resistance. In order to restore sufficient ductility to flange (16) of the shoe (10) that will be cold worked, a solution treatment is performed at a temperature range of 2050 DEG to 2250 DEG F. in a non-oxidizing environment. The wear surface (12) and back flange (14) are maintained at a cooler temperature by engagement of the shoe (10) with a copper part, such that the coated surfaces do not lose their coating. The flange area (16) of the shoe (10) is then cold worked by crimping in order to form the material to the round shape of the piston head (42).</p> |
