As shown in FIGS. 31 and 33, the outer cooling part 713 is provided with installation recesses 713b each recessed in a radially inward direction. The bottom surface of the installation recess 713b is the installation surface 713a, and the power module 110 and the smoothing capacitor C2 are received in the installation recess 713b. Three installation recesses 713b are arranged in the circumferential direction γ, and one set of the power module 110 and the smoothing capacitor C2 is received in one installation recess 713b. In the radial direction β, the depth dimension of the installation recess 713b is larger than both the thickness dimension of the power module 110 and the thickness dimension of the smoothing capacitor C2. The installation recess 713b has an inner wall surface 713c extending radially outward from the installation surface 713a. The inner wall surface 713c surrounds the power module 110 and the smoothing capacitor C2 from all sides. The inner wall surface 713c is spaced apart from the power module 110 and the smoothing capacitor C2 in the axial direction α and the circumferential direction γ.
