PURPOSE: To prevent deterioration in insulation of a motor coil part due to dew condensation, by a method wherein a motor is pressed in a molded part, formed in a recessed shape as seen from a cool air passage, through a spacer, and the output shaft surface of the motor is positioned approximately flush with a partition wall surface.

CONSTITUTION: A cool air partition plate 6' is molded in a recessed shape, as seen from a cool air passage, so that a motor 3 is prevented from exposure to the interior of the cool air passage, and the motor 3 is mounted in the recessed part. The outlet of a lead wire 12 is separated from a high temperature part by the use of a seal material 10. A space 11 serves to adjust a size when the motor 3 having a different size is mounted, and to level the cool air passage. This constitution enables a motor for drive to be completely installed in the cool air passage, and permits prevention of the occurrence of deterioration in electric characteristics due to dew condensation.