Electrically powered pump

Abstract

An electrically powered pump includes a pump arrangement that pumps a liquid, and an electric motor arrangement that has a stator and a rotor that are installed on a passage through which the liquid pumped by the pump arrangement flows. At least one of the stator and the rotor has a winding wire that generates a magnetic field when it is energized to rotate the rotor with respect to the stator to drive the pump arrangement. The winding wire has a conductive body through which an electric current passes and an insulation body that insulates the conductive body. The conductive body is made of a material predominantly composed of carbon. Thereby, the liquid pumped by a pump arrangement is prevented from corroding the winding wire.

Description

CROSS REFERENCE TO RELATED APPLICATION[0001]This application is based on and incorporates herein by reference Japanese Patent Application No. 2008-017085 filed on Jan. 29, 2008.BACKGROUND OF THE INVENTION[0002]1. Field of the Invention[0003]The present invention relates to an electrically powered pump that has an electric motor arrangement for driving a pump arrangement.[0004]2. Description of Related Art[0005]In recent years, selective reduction (SCR: Selective Catalytic Reduction) type urea SCR system is under development, and partly put into actual use. The SCR system is installed in an internal combustion engine (especially diesel engine) of a vehicle, etc., to reduce NOx (nitrogen oxides) in exhaust gas.[0006]In the urea SCR system, a selective reduction type NOx cleaning catalyst (SCR catalyst) is installed in an exhaust pipe of an internal combustion engine, and a urea water addition valve, which adds urea water (urea water solution) as a reducing agent to the exhaust gas in ...

AI Technical Summary

Benefits of technology

[0012]Thus, it is an objective of the present invention to provide an electrically powered pump that has an electric motor arrangement for driving a pump arrangement, in which a liquid pumped by a pump arrangement is prevented from corroding a winding wire.

Problems solved by technology

However, when the conventional electrically powered pump was used as the urea water pump as it is, corrosion of winding wires, which are described below, became a problem.

The inventor found that it is further required to take measures against corrosion of the winding wires, since urea water easily permeates the above-mentioned covering resin and the insulator compared with mere water, and easily corrodes the copper conductive body.

In addition, such problems as the corrosion of the winding wires are caused not only by urea water but by other liquids except water.

Also in an electrically powered pump that pumps such fuel to fuel injection valves, there is a concern that the fuel may permeate the covering resin and the insulator to corrode the copper conductive body.

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