| 摘要 |
An electro hydraulic servo valve has a pair of oppositely polarized magnets (32, 34) mounted in the center of the spool (20) of the valve to be controlled. A Hall effect sensor (40) is mounted in the housing (50) adjacent the magnets (32, 34) to precisely measure the position of the spool relative to the housing. The magnets and transducer are mounted at the axial center of the spool to eliminate spurious signals, due to temperature, vibrations, shock, or variations in hydraulic supply pressure and back pressure. The strength and shape of the magnets (32, 34) and width of the air gap between them are chosen to provide a linear output signal over the range of displacement desired and to provide the accuracy of location necessary for the particular configuration. <IMAGE>
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