| 摘要 |
PROBLEM TO BE SOLVED: To detect the position of a reciprocating member accurately without malfunctioning for a disturbed magnetic field while achieving a miniaturization of a position detector. SOLUTION: This position detector of an actuator is used for detecting the position of a reciprocating member sensing a magnetic force of a permanent magnet 12a provided on the reciprocating member. This position detector comprising semiconductor thin film magnetic resistors MR1-MR4 has a sensor body 20 which produces an output to a signal processing part and is formed on a sensor base 31 made of a magnetic material and the sensor base 31 is magnetized. Magnetic field focusing members 33 and 34 comprising a magnetic material are arranged in the sensor body 21 so that a biased magnetic field is applied from the sensor base 31 acting as permanent magnet. Thus, a magnetic force of the permanent magnet 12a of the reciprocating member is focused by the magnetic focusing members 33 and 34 to be applied to the sensor body 20.
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