To provide a water pump capable of attaining miniaturization by simplifying a construction and dispensing with a seal between a driving rotor and a driven rotor and water proof processing on a driving rotor side.
A driving shaft 22 is rotatably supported on a body casing 4. An impeller 31 is provided at an end of a driven shaft 32 provided to project in a cooling path A. The driven shaft 32 is constructed to be axially extensible and retractable and is biased in a retraction direction. A temperature sensitive magnetic body 5 having a characteristic of decreasing spontaneous magnetization along with temperature rise is provided at the other end of the driven shaft 32 and a magnet 23 is provided on the drive shaft 22 for attracting the temperature sensitive magnetic body 5. A magnet 25 is also provided on the drive shaft 22 to face a guide ring 35 in a state that the driven shaft 32 is retracted. A separation wall 6 is consecutively provided on a mounting plate 41 for separating the drive rotor 2 and the driven rotor 3 and introduction/discharge holes 42 are formed in the mounting plate 41.
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ADACHI KAZUNARI
SAKUMOTO TAKASHI
AISIN SEIKI
Kunitomi Go