An inner peripheral water entry reducing portion and an outer peripheral water entry reducing portion are provided. The inner peripheral water entry reducing portion includes an inner peripheral wall portion surrounding an output shaft. The outer peripheral water entry reducing portion includes an outer peripheral wall portion surrounding the inner peripheral wall portion. At least one inner peripheral opening of the inner peripheral water entry reducing portion and at least one outer peripheral opening of the outer peripheral water entry reducing portion are prevented from overlapping with each other in a circumferential direction of the output shaft.