| 摘要 |
PROBLEM TO BE SOLVED: To detect the opening of a throttle valve at a high accuracy free from effect of any temperature change, even in a state that there is a sudden change in the temperature of the atmosphere. SOLUTION: This opening sensor made up of a rotor 3 mounted on a throttle shaft 1, a permanent magnet 5 which is provided at the tip of the rotor 3 and rotates together with the shaft 1 and the rotor 3, a Hall element 10 which is fixed at the center part of the rotation of the magnet 5 to output an electrical signal corresponding to the direction of a magnetic field thereof and a circuit board 20 which drives the Hall element 10 while compensating temperature characteristics of the magnet 5 and the Hall element 10 to process outputs thereof. Here, a circuit chamber 7 is filled with a silicon gel 30 to increase the heat capacity of the circuit board 20 and a resin material having a cut in the perimeter thereof is arranged at a coupled part 3a of the rotor 3 to the throttle shaft 1 to cut off heat transmitted to the magnet 5 from the side of the shaft 1. Thus, the temperature environment is made almost the same for the circuit board 20, the magnet 5 and the Hall element 10.
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