Metal working – Method of mechanical manufacture – Electrical device making
Patent
1995-05-24
1997-09-02
Hall, Carl E.
Metal working
Method of mechanical manufacture
Electrical device making
29732, 228184, H02K 1514
Patent
active
056618948
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a method for use in assembling a variety of electric motors including an electric motor section of a scroll compressor to be employed in an air conditioner.
BACKGROUND ART
A scroll compressor for use in an air conditioner has a construction as shown in FIG. 8 where a compressor section 8 is integrated with an electric motor section 7 composed of a casing body 1, a stator 2, a rotor 3, a rotary shaft 4, an upper bearing 5, and a lower bearing 6. In the electric motor section 7, the stator 2 is fixed inside the cylindrical casing body 1 by shrink fitting or a similar method. The rotor 3 is inserted in the stator 2 with a specified gap being formed between the rotor 3 and the stator 2. The rotor 3 is fixed around the rotary shaft 4 which serves as a crankshaft by press fitting the rotor 3 to the rotary shaft 4. The upper bearing 5 and the lower bearing 6 are mounted in both end portions of the casing body 1 while rotatably supporting the rotary shaft 4.
The electric motor section 7 of such a scroll compressor is assembled normally according to a procedure as shown in FIG. 9. The casing body 1 in which the stator 2 has been inserted is vertically inverted, and the upper bearing 5 is fixed into a lower end portion of the casing body 1 by welding. The rotary shaft 4 around which the rotor 3 has been mounted is inserted into a center portion of the casing body 1 with a lower end portion of the rotary shaft 4 inserted into the upper bearing 5. The lower bearing 6 is inserted into an upper end portion of the casing body 1 with an upper end portion of the rotary shaft 4 inserted into the lower bearing 6, and the lower bearing 6 is fixed by welding. The upper bearing 5 and the lower bearing 6 are both mounted to the casing body 1 with the inner peripheral surface of the casing body 1 used as a reference surface for positioning.
According to the assembling procedure described above, when the casing body is formed in a complete cylinder shape, the centers of the bearings 5 and 6 coincide with the center of the casing body 1 to achieve an even gap between the stator 2 and the rotor 3. However, the method of producing the casing body 1 has been simplified for cost reduction in a recent scroll compressor. The casing body 1 may be produced by rolling a flat plate into a cylindrical shape. The casing body 1 thus produced has a degraded dimensional accuracy. When the bearings 5 and 6 are directly mounted to the casing body 1, the centers of the bearings 5 and 6 are displaced from the center of the stator 2, which results in an uneven gap between the stator 2 and the rotor 3 to significantly reduce the performance of the electric motor. Therefore, it is impossible to use a casing body 1 having low dimensional accuracy, which has been a cause of hampering the cost reduction of the scroll compressor.
DISCLOSURE OF THE INVENTION
Accordingly, the object of the present invention is to provide a method for assembling an electric motor capable of maintaining the evenness of a gap between a stator and a rotor when a casing body has low dimensional accuracy.
In order to achieve the above-mentioned object, the present invention provides a method for assembling an electric motor wherein bearings, each having an outer diameter smaller than an inner diameter of a casing body such that a gap is formed between the bearing and the casing, are each mounted to each of both ends of the casing body in which a stator is inserted, with a rotary shaft around which a rotor is mounted is supported by the bearings at a center portion of the casing body, the method comprising: a first bearing assembling step of inserting the first bearing into a first end of the casing body in which the stator is inserted and fixed, holding the first bearing in an assembling position with the center of the first bearing placed in a specified position, and plug welding the casing body to the one bearing in a plurality of locations on an outer peripheral surface of the casing body while holding the casing body in an
REFERENCES:
patent: 3165816 (1965-01-01), Thompson et al.
patent: 3172197 (1965-03-01), Rutledge
patent: 5127148 (1992-07-01), Lykes et al.
Inoue Takayoshi
Kawasaki Kenji
Maki Yasuo
Daikin Industries Ltd.
Hall Carl E.
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