Patent ID: 7091808
Filing Date: 2006-08-15
Classification: H01F

Abstract:
1. A solenoid comprising: an excitation coil; a slider disposed in a central part of the excitation coil; and a yoke including a first yoke part that covers one end surface of the excitation coil and has a facing surface that faces an outer circumferential surface of the slider, a second yoke part that covers another end surface of the excitation coil and has a facing surface that faces the outer circumferential surface of the slider, and a linking part that links the first yoke and the second yoke and covers an outer circumferential part of the coil, the yoke forming a closed magnetic path together with the slider, wherein a bearing is fitted in both end sections of the first yoke part and the second yoke part including the facing surfaces, is disposed on an outer circumference of the slider, and guides the slider in a movable state, the bearing being made of a nonmagnetic body, n (where n is a positive integer of 0 or higher) grooves, which are provided so as to be concave around an inner circumference, and n+1 tooth parts, which are adjacent to the grooves and function as magnetic poles, are provided in the facing surface of the first yoke part, m (where m is a positive integer of 0 or higher) grooves, which are provided so as to be concave around an inner circumference and m+1 tooth parts, which are adjacent to the grooves and function as magnetic poles, are provided in the facing surface of the second yoke part, n+1 grooves, which are provided so as to be concave around an outer circumference, and n+1 tooth parts, which are adjacent to the grooves and function as magnetic poles, are provided in a surface of the slider that faces the first yoke part, and m grooves, which are provided so as to be concave around an outer circumference, and m tooth parts, which are adjacent to the grooves and function as magnetic poles, are provided in a surface of the slider that faces the second yoke part.