Motor-driven compressor

The present invention relates to a motor-driven compressor having a compression mechanism, an electric motor and an inverter aligned in a housing in axial direction of a rotary shaft of the compressor.

Such compressor is disclosed, for example, in Japanese Unexamined Patent Application Publication No. 2000-291557. The compressor has a housing assembly (hereinafter referred to as a housing) composed of a front housing, an intermediate housing and a rear housing. The compression mechanism of a scroll-type, the motor and the inverter are aligned in this order in the housing in axial direction of the rotary shaft of the compressor. The motor is controlled by the inverter and drives the compression mechanism for compression of refrigerant gas. A stator of the motor has a coil, and a rotor of the motor is mounted on the rotary shaft. The front housing has a refrigerant inlet port at the periphery. The inlet port is disposed forward of the coil end. In such kind of compressor, there is a need for reduction of its axial length.

In another known compressor disclosed in Japanese Unexamined Patent Application Publication No. 4-80554, the inlet port is disposed at a position radially facing the coil end. Therefore, the axial length of the compressor is small, as compared to the case of the reference No. 2000-291557.

In the compressor of the reference No. 4-80554 wherein the inlet port is radially spaced away from the coil end, so that refrigerant gas flows smoothly from the inlet port into the housing, but the diameter of the housing is enlarged.

The present invention is directed to providing a motor-driven compressor that allows refrigerant gas to flow smoothly from an inlet port into a housing without enlarging the diameter of the housing.

In accordance with an aspect of the present invention, a motor-driven compressor includes a housing having an inlet port, a compression mechanism for compression of refrigerant introduced via the inlet port into the housing, an electric motor having a stator core and a coil, an inverter for driving the electric motor, and a rotary shaft rotated by the electric motor thereby to drive the compression mechanism. The compression mechanism, the electric motor and the inverter are aligned in the order in the housing in axial direction of the rotary shaft. The coil has a coil end projecting toward the inverter from the stator core and being disposed adjacent to an inner peripheral surface of the housing. The inlet port is located so as to face the coil end. A recess is formed on the inner peripheral surface of the housing for communicating with the inlet port. The recess extends in the axial direction of the rotary shaft toward the inverter beyond the coil end.

Other aspects and advantages of the invention will become apparent from the following description, taken in conjunction with the accompanying drawings, illustrating by way of example the principles of the invention.

The following will describe the first embodiment of the present invention with reference to FIGS. 1 and 2. FIG. 1 Shows a motor-driven compressor 10 of the first embodiment. The compressor 10 is used in a refrigeration circuit 11 of a vehicle air conditioner. It is noted that the right-hand side as viewed in FIG. 1 is the front side of the compressor 10 and the left-hand side is the rear side of the compressor 10.

Referring to FIG. 1, the refrigeration circuit 11 includes a condenser C, an expansion valve V and an evaporator E, as well as the compressor 10. In the refrigeration circuit 11, high-pressure and high-temperature refrigerant gas discharged from the compressor 10 is cooled and condensed by the condenser C. The flow of the refrigerant from the condenser C is controlled by the expansion valve V. The refrigerant from the expansion valve V is evaporated in the evaporator E. The refrigeration circuit 11 is provided with a temperature sensor S and a controller CN. The temperature sensor S detects the temperature of the refrigerant from the evaporator E. The controller CN is connected to the expansion valve V for controlling the opening of the expansion valve V in response to a signal from the temperature sensor S.