Electrical generator or motor structure – Dynamoelectric – Rotary
Patent
1990-08-23
1992-08-25
Skudy, R.
Electrical generator or motor structure
Dynamoelectric
Rotary
310 42, 310 91, 310254, 310259, H02K 100
Patent
active
051421798
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a stator structure of a built-in motor to be incorporated into the spindle or the like of a machine tool.
BACKGROUND ART
A built-in type spindle motor for driving the spindle of a machine tool or the like has been increasingly used recently, to meet the demand for cost reductions, floor space reductions, and miniaturization. The stator of a built-in motor for such a purpose must be accurately fixed to the spindle head housing or the like of a machine tool, and a stator core is built up by superposing high-permeability steel laminations and fixedly uniting the superposed laminations by welding the circumference thereof, and then the stator core is finished to an accurate external size by grinding.
As the laminations of the stator core are welded only in the circumference of the stator core, however, the laminations are not fastened together in the inside portion of the stator core, and thus the inside portion of the stator core has a low rigidity but the outside portion of the stator core has a high rigidity. Therefore, it is possible that the stator core is deformed with a lapse of time when the stator core having such a construction and held by a mandrel is ground and is removed from the mandrel after grinding. It is also possible for the stator core to be deformed during transportation or when subjected to a winding process or a varnish-impregnating process.
DISCLOSURE OF THE INVENTION
Accordingly, an object of the present invention is to provide a stator structure having the least possibility of deformation after manufacture.
In view of the foregoing object, in a first aspect of the present invention, a stator of a built-in motor is built up by superposing laminations coated with a thermosetting adhesive.
In a second aspect of the present invention, a stator of a built-in motor is built up by superposing laminations, each provided with through holes, and by welding the outer circumference of the laminated structure and pressing connecting bars provided with projections in the circumferences thereof into the through holes of the laminated structure.
In a third aspect of the present invention, a stator of a built-in motor is built up by superposing laminations, each provided at predetermined positions with projections formed by pressing so as to project in one direction, with the projections engaging the adjacent laminations to form a laminated structure, and welding the outer circumference of the laminated structure.
The rigidity of the inside portion of any one of those stator is enhanced, as well as the outside portion of the same, by the adhesive and the connecting bars or the projections, so that the difference in the rigidity of the outside portion and the inside portion is small, and consequently, the stator is less liable to be deformed. When the laminations are coated entirely with the adhesive, in particular, the difference in the rigidity of the outside portion and the inside portion is reduced to the smallest extent possible, and the stator has a high rigidity.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a front view of a rotor core according to the present invention;
FIG. 2a is a sectional view of the rotor core taken along the line II--II in FIG. 1;
FIG. 2b is an enlarged broken portion of FIG. 2a showing the coated adhesive.
FIG. 3 is a front view of a rotor core in a second embodiment according to the present invention;
FIG. 4 is a fragmentary sectional view taken along the line IV--IV in FIG. 3;
FIG. 5 is a front view of a rotor core in a third embodiment according to the present invention; and
FIG. 6 is a fragmentary perspective view of a serrated bar.
BEST MODE OF CARRYING OUT THE INVENTION
Preferred embodiments of the present invention will be described hereinafter with reference to the accompanying drawings. Referring to FIGS. 1 and 2a, 2b, a stator core 10, i.e., the body of a stator for a motor, is built up by a plurality of stocked, superimposed high-permeability steel laminations 12. The stator core 10 is fabricated by
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Hayashi Yoshiyuki
Kimijima Masami
Nakamura Kosei
Numai Kazuhisa
Fanuc Ltd.
Skudy R.
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