In the development of a magnetic coupling type water pump, the coupling pull-out phenomena, which leads to the impeller stopping, has been a concern. As a result of analysis of magnetic coupling behavior, two-types of pull-out were determined: pull-out due to insufficient transmission torque of the magnetic coupling in the high speed rotation range; and, pull-out due to the resonance of the inner and outer magnets. Major factors causing pull-out are the angular velocity input to the drive side, the inertia moment of the driven side, magnetic coupling characteristics, and the damping effect of coolant. Using the results of actual testing and a behavior simulation of a water pump, design specifications for a magnetic coupling were set within conditions that did not allow pull-out to occur. Consequently, the reliability of drive power transmission was assured. As a result, it was possible to decrease the size and weight of the water pump, and, at the same time, decrease engine friction.
Article of Honda R&D Technical Review Vol.13 No.2 (67 - 74)