Patent ID: 8106731

Claim:
An electromagnetic switch for a starter comprising: an electromagnetic coil that is energized when a key switch is turned on; a plunger that is driven by electromagnetic force produced across the energized electromagnetic coil, thereby traveling in a predetermined direction; a pair of fixed contacts that are spaced apart from each other; a movable contact that travels due to a travel of the plunger and makes contact with the pair of fixed contacts so as to make a short circuit across the pair of fixed contacts; a switch cap that is made of an insulative material and incorporates the pair of fixed contacts and the movable contact; a battery terminal that is connected with one of the pair of fixed contacts and is disposed in such a way as to be exposed outside the switch cap; and a motor terminal that is connected with the other one of the pair of fixed contacts and is disposed in such a way as to be exposed outside the switch cap, electric power being supplied from a battery connected with the battery terminal to a starter motor connected with the motor terminal, when the movable contact makes a short circuit across the pair of fixed contacts, wherein, on the outer surface thereof, the switch cap is provided with a diaphragm disposed between the battery terminal and the motor terminal; and the diaphragm is formed in such a way that a wall face thereof, that faces the battery terminal, protrudes convexly toward the battery terminal.