An inner peripheral surface of an upper plate of a first case has a first inclined surface that faces an outer peripheral surface of a seal holding member of a motor in a radial direction of a rotary shaft. An inner peripheral surface of a seal fixing member has a second inclined surface that also faces the outer peripheral surface of the seal holding member in the radial direction. The outer peripheral surface has third and fourth inclined surfaces along an axial direction of the rotary shaft. An outside diameter on sides of the third and fourth inclined surfaces that are far from each other is greater than an outside diameter on sides of the third and fourth inclined surfaces that are near each other. A sealing member is installed in an annular space that is surrounded by the first, second, third, and fourth inclined surfaces.
