Patent ID: 8680416

Claim:
A dial switch comprising: a rotatably operable dial knob rotatable in a rotary direction, the dial knob including: a rotary portion configured to rotate due to a rotational operation of the dial knob, the rotary portion having an uneven peripheral surface having a concave portion and a convex portion such that the peripheral surface radially retracts and projects in a radial direction orthogonal to the rotary direction while passing through a center of the rotation of the dial knob, the concave portion and the convex portion being alternately repeated along the rotary direction; a plunger which is capable of being brought into contact with the uneven peripheral surface; a plunger holding portion which holds the plunger such that the plunger is movable in a reciprocating manner in the radial direction so that the plunger is brought into contact with the uneven peripheral surface; and a compression coil spring which biases the plunger toward the uneven peripheral surface, wherein the plunger holding portion extends along a moving path of the plunger, and has a guide surface which surrounds the plunger from an outside of the moving path, and the plunger further includes: a receiving portion facing a side opposite to the uneven peripheral surface in front of the receiving portion, the receiving portion being configured to be brought into contact with one end of the compression coil spring, and the receiving portion being configured to receive the biasing force; an outer wall has an outer peripheral surface which extends in the moving path direction of the plunger and is arranged close to the guide surface, and an inner peripheral surface having an inner diameter larger than an outer diameter of the compression coil spring; and an inner shaft extends in the moving path direction inside the outer wall, has a rear end at a position in front of the rear end of the outer wall, and has an outer diameter which allows the compression coil spring to be mounted on an outer side thereof, wherein the compression coil spring is arranged on the plunger holding portion in a state where the compression coil spring is mounted outside the inner shaft and is deformed by resilient compression in the center axis direction of the compression coil spring so that the compression coil spring pushes the plunger to the uneven peripheral surface by a resilient repulsive force of the compression coil spring, and the difference between a maximum outer diameter of the inner shaft and an inner diameter of the compression coil spring is smaller than the difference between a minimum inner diameter of the inner peripheral surface of the outer wall and an outer diameter of the compression coil spring.