Patent ID: 7874541

Claim:
A proportional solenoid, comprising: an electromagnetic coil; a fixed yoke provided immovably inside the electromagnetic coil and having a convex portion formed at an edge portion of an end surface of the fixed yoke; and a movable yoke that is disposed inside the electromagnetic coil, has a tip portion thereof inserted into the convex portion of the fixed yoke, and is provided movably relative to the fixed yoke, the proportional solenoid enabling the position adjustment of the movable yoke by controlling an electric current applied to the electromagnetic coil, wherein a protruding portion that protrudes at the side of the fixed yoke is formed at an edge portion of the surface of the movable yoke on the side of the fixed yoke, and an inner surface of the protruding portion is tapered such that the inner surface is located further outside as the inner surface approaches the fixed yoke and an outer surface of the protruding portion is formed to extend substantially parallel to an axial line of the movable yoke, and wherein an end surface extending in a direction substantially perpendicular to the axial line of the movable yoke is formed at the tip of the protruding portion, and a radial length of the end surface is set such that a radial magnetic flux flowing in a radial direction from the outer surface of the protruding portion is larger than an axial magnetic flux flowing in an axial direction from the end surface.