Patent ID: 7355306

Claim:
A motor driven blower comprising: a blowing fan; a support member including a scroll casing made of resin and a motor support plate made of a metallic plate, the scroll casing and the motor support plate being arranged to define a spiral air passage in which the blowing fan is accommodated; a drive motor including a stator, a rotor which rotates a rotary shaft engaged with the blowing fan, and a motor body on which the rotary shaft is supported through a bearing, the motor body including a flange formed on the motor body extending along an outside of the motor support plate; and a plurality of supports arranged around the motor body, each of the supports including a vibration proof rubber attaching hole formed on the motor support plate, a vibration proof rubber fitted in the vibration proof rubber attaching hole, and an engaging member engaging the flange onto the vibration proof rubber so that the drive motor is supported on the motor support plate via the vibration proof rubber, wherein the drive motor generates a vibration including frequency components not less than 1 KHz, the vibration proof rubber has a damping characteristic showing a damping factor not more than 0.5 at 1 kHz and less damping factor in a frequency region higher than 1 kHz, and the motor support plate further including a resonance frequency adjustment section formed around the drive motor supported thereon, the resonance frequency adjustment section is formed with a plurality of bead-shaped protruding portions on a surface thereof in order to adjust a resonance frequency of the motor support plate in a drum mode to not less than 1 kHz.