Water pump

Abstract

The present invention provides a water pump capable of minimizing the runout of a shaft of an impeller even if a bearing supporting the shaft is provided only at one location. This water pump includes a pump cover, a motor case having a partition wall part, an impeller that is rotatably housed in a pump chamber, a shaft, a radial bearing, a rotor base formed with a shaft connecting part to which the shaft is press-fitted and fixed, an inner magnet that is fixed to an outer periphery of the rotor base, and a stator core mounted in the motor case. A substantially cylindrical bearing housing part is formed in partition wall part, the radial bearing is inserted and fixed to the bearing housing part, the radial bearing is disposed in the rotor base, and an axial direction overall length of the radial bearing is positioned within a substantial area of an axial direction overall length of the inner magnet.

Description

BACKGROUND OF THE INVENTION[0001]1. Field of the Invention[0002]The present invention relates to a water pump capable of minimizing the runout of a shaft of an impeller even if a bearing supporting the shaft is provided only at one location.[0003]2. Description of the Related Art[0004]In recent years, expectations and demands for fuel-efficient cars are increasing more than ever from an environmental perspective. Various means are being developed and implemented for achieving low fuel consumption, and the development and implementation of the electrification of various components to be mounted on vehicles pursuant to the hybridization of vehicles are also being advanced with great urgency. Among the above, a water pump is a component that not only cools the engine, it is also responsible for optimizing the temperature (raising and lowering the temperature to become optimal) of the various components in the vehicle, and is a component that is indispensible for a vehicle.[0005]Thus, t...

AI Technical Summary

Benefits of technology

[0021]With the invention of claim 1, as a result of disposing the entire thrust direction of the radial bearing in the area of the axial direction of the inner magnet, precession will not occur easily to the shaft of the inner rotor, and abrasion of the radial bearing is inhibited. Thus, the life of the radial bearing is extended, and the life of the electric water pump is consequently extended. In addition, since the entire axial direction length of the radial bearing is fitted in the area of the axial direction of the inner magnet, the axial direction length of the electric water pump can be shortened, and the overall water pump can be further miniaturized and made lighter.

[0022]With the invention of claim 2, the axial direction overall length of the radial bearing intersects with the virtual center line of the axial direction overall length of the inner magnet. Consequently, with this configuration, it will be more difficult for precession to occur to the shaft. With the invention of claim 3, by adopting a configuration where the radial bearing and the connecting part formed with a hole part for press-fitting the shaft of the rotor base are fitted in the area of the axial direction of the inner magnet, the dimension of the overall pump can be made the smallest.

[0023]With the invention of claim 4, the micro vibration in the axial direction that occurs in the electric water pump can be absorbed by using the elastic member, and it is possible to prevent shock being inflicted on the radial bearing. In particular, ceramic that is susceptible to shock can also be used as the bearing. As a result of being able to use ceramic as the thrust bearing, the functions of high heat resistance, chemical resistance (coolant), high degree of hardness, and high durability can be realized, deterioration with age will be minimal, and the bearing life can be extended.

[0024]In addition, since the elastic member is mounted between the housing part and the radial bearing, even if the shaft of the impeller is subject to precession, since the back face side of the thrust bearing is buffered and protected by the elastic member, the thrust bearing is able to continue sliding uniformly relative to the radial bearing based on the elasticity and flexibility of the elastic member. Thus, a radial bearing made of carbon can be subject to abrasion uniformly along the axial direction, and the bearing life of the radial bearing can be extended.

Problems solved by technology

This change is unpredictable and random since factors other than the pump; for instance, engine vibration and the like, become involved.

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