| 摘要 |
In this electric parking brake device, electrical power loss is low when detecting the displacement or position of a plunger without providing a sensor, and the mounting space is also caused to be low. A resonance capacitor (54) is connected to the coil (37) of a solenoid (9), forming a resonance circuit, and a drive current to which is superposed a resonance frequency is input to the solenoid (9) forming the resonance circuit. As a result, when the position of the plunger (10) within the coil (37) changes, the inductance of the coil (37) changes, and the resonance frequency moves. From said change, the position or displacement of the plunger (10) is detected without providing a sensor, and so the installation space thereof is not required. In such a manner, a resonance output is superposed and the changes in detection value (changes in resonance point) of both ends of the solenoid (9) are detected, and so a large electrical power is not required and losses are low. |
