Pumps – Motor driven – Including means utilizing pump fluid for augmenting cooling,...
Reexamination Certificate
1999-11-26
2001-05-22
Walberg, Teresa (Department: 3742)
Pumps
Motor driven
Including means utilizing pump fluid for augmenting cooling,...
Reexamination Certificate
active
06234768
ABSTRACT:
CROSS REFERENCE TO RELATED APPLICATION
This application is based on and incorporates herein by reference Japanese Patent Application No. Hei. 10-354786 filed on Dec. 14, 1998.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a sealed-type electric compressor having an electric motor and a compression mechanism within a compressor housing, suitable for use in a refrigerating cycle of an automotive air conditioning system.
2. Description of Related Art
Recently, a hybrid vehicle driven by a combustion engine and an electric motor, and an electric vehicle driven by an electric motor has been developed for reducing exhaust emissions. In accordance with the development of these vehicles, a sealed-type electric compressor driven by an electric motor has also been developed for an air conditioning system of these vehicles.
The electric compressor is installed in a vehicle engine compartment such that the rotor shaft thereof is horizontally arranged for lowering the height of hood to increase visibility.
In the electric compressor, refrigerant discharged from a compression mechanism flows through a motor chamber, where the electric motor is installed, to cool the motor, then is discharged from a compressor housing. However, when the refrigerant simply flows through the motor chamber, pressure-loss of the refrigerant increases. Thus, in general, a refrigerant passage is provided between the housing and a stator of the electric motor for guiding the refrigerant.
However, since the electric motor is installed such that the rotor shaft thereof is horizontally positioned, lubricating-oil lubricating sliding portions of the compressor is stored on the bottom of the motor chamber. The lubricating-oil stored in the motor chamber blocks the refrigerant passage formed at the lower portion of the compressor.
Thus, the cross-sectional area of the refrigerant passage is substantially reduced, so that the pressure loss of the refrigerant increases in the motor chamber. Further, the lubricating-oil stored on the motor chamber bottom is caught in the refrigerant, and is discharged with the refrigerant from the compressor.
In such a situation, when a predetermined amount of the lubricating-oil flows out of the compressor, the sliding portions are not sufficiently lubricated and the heat exchanging efficiencies of a condenser and a an evaporator are reduced.
SUMMARY OF THE INVENTION
An object of the present invention is to suppress a pressure loss of the refrigerant in the motor chamber, and to prevent the lubricating-oil from being discharged with the refrigerant, even when the electric compressor is installed such that the rotor shaft is horizontally positioned.
According to a first aspect of the present invention, fluid (refrigerant) passages of the compressor include an upper fluid passage and a lower fluid passage. The upper fluid passage is positioned at one side with respect to a datum line extending through a center of the rotor shaft and perpendicularly to the rotor shaft, and the lower fluid passage is positioned on the other side of the datum line. A cross-sectional area of the upper fluid passage is larger than a cross-sectional area of the lower fluid passage.
When the electric compressor is installed such that the datum line is substantially horizontally positioned, the upper fluid passage having the larger cross-sectional area is located above an oil surface of the lubricating-oil stored in the motor chamber, and the lower fluid passage having the smaller cross-sectional area is located under the oil surface.
Thus, even when the electric compressor is installed such that the rotor shaft is horizontally positioned and the lubricating-oil blocks the lower fluid passage, the fluid discharged from the compression mechanism to the motor chamber flows through the upper fluid passage, thereby reducing the pressure loss of the fluid.
Further, most of the fluid discharged from the compression mechanism to the motor chamber flows through the upper fluid passage, so that the lubricating-oil stored in the motor chamber is not caught in the fluid, and is not discharged with the fluid from the compressor.
According to a second aspect of the present invention, an upper fluid passage is positioned above an oil surface of the lubricating-oil stored in the motor chamber, and a lower fluid passage is positioned under the oil surface. A cross-sectional area of the upper fluid passage is larger than a cross-sectional area of the lower fluid passage.
Thus, as in the first aspect of the present invention, even when the electric compressor is installed such that the rotor shaft is horizontally positioned, the pressure-loss of the fluid in the motor chamber is reduced and the lubricating-oil is prevented from being discharged with the fluid from the compressor.
According to a third aspect of the present invention, a fluid passage is formed at only one side with respect to a datum line extending through a center of said rotor shaft and perpendicularly to said rotor shaft.
Thus, as in the first aspect of the present invention, even when the electric compressor is installed such that the rotor shaft is horizontally positioned, the pressure loss of the fluid in the motor chamber is reduced and the lubricating-oil is prevented from being discharged with the fluid from the compressor.
According to a fourth aspect of the present invention, the fluid passage is formed only above an oil surface of lubricating-oil stored in the chamber.
Thus, as in the first aspect of the present invention, even when the electric compressor is installed such that the rotor shaft is horizontally positioned, the pressure loss of the fluid in the motor chamber is reduced and the lubricating-oil is prevented from being discharged with the fluid from the compressor.
REFERENCES:
patent: 4781542 (1988-11-01), Ozu et al.
patent: 5222874 (1993-06-01), Unnewehr et al.
patent: 6155802 (2000-12-01), Choi et al.
patent: 57-129287 (1982-08-01), None
Harakawa Yoshiaki
Iriyama Kenji
Sanuki Masami
Tsumagari Yuichi
Denso Corporation
Patel Vinod D
Pillsbury & Winthrop LLP
Walberg Teresa
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