Metal working – Method of mechanical manufacture – Electrical device making
Reexamination Certificate
2001-01-18
2003-04-22
Bryant, David P. (Department: 3726)
Metal working
Method of mechanical manufacture
Electrical device making
C310S216006, C029S606000
Reexamination Certificate
active
06550130
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a divided stator and a manufacturing process for a divided stator used in a rotating electric apparatus, and more specifically, to a manufacturing process that can rigidly connect pole pieces by a simple operation while maintaining accurate positioning of the pole pieces.
2. Discussion of the Related Art
In a rotating electric apparatus, in order to simplify coil winding of the stator, a divided stator has been proposed in which a plurality of pole piece laminates are arranged in a ring, and the inside pole portions of pole piece laminates are connected with synthetic resin, etc. to form an iron core. After winding coil between slots of the iron core, the iron core is fitted into a cylindrical outer ring yoke (see Japanese Utility Model Application Laid-open No. Hei 2-44848 (1990) and Japanese Patent Application Laid-open No. Hei 4-58746 (1992)).
On the other hand, in order to position pole pieces accurately with respect to each other and to ensure durability and reliability of the stator, the applicant of the present invention has proposed a process for manufacturing an iron core by integrally forming an iron core blank in which a plurality of pole pieces are arranged in the form of a ring. A bridge portion is formed between adjoining ends of the inner circumferential tip of each pole piece protruding from the inner circumferential end inwards or between adjoining ends of the outer circumferential tip protruding from the outer circumferential end outwards. This is followed by laminating a plurality of iron core blanks and fixing them to each other, fitting them into forming dies to connect them with a synthetic resin material, and then cutting the bridge portion protruding either inwards or outwards (see Japanese Patent Application No. Hei 4-117035).
However, in the above-mentioned manufacturing process, since a plurality of iron core blanks are stacked and inserted in forming dies and portions of the pole pieces are connected with a synthetic resin material, a complicated process for inserting iron core blanks and injecting synthetic resin material are required. Since the pole pieces are connected by covering them with synthetic resin, the connection strength between adjoining pole pieces is low, and the pole piece connecting operation and bridge portion cutting operation must be carried out separately, which complicates the process.
SUMMARY OF THE INVENTION
In view of the foregoing, it is an object of the invention to provide a manufacturing process for a divided stator which can be rigidly connected by a simple operation while accurately positioning the pole pieces.
The manufacturing process for a divided stator according to the invention comprises forming an iron core having outer circumferential slots by arranging a plurality of pole pieces having inner pole portions in a ring and connecting the inner pole portions of a plurality of adjoining pole pieces to one another;
winding coil around the outer circumferential slots of the iron core, and inserting the iron core into an outer ring yoke provided with a cylindrical inner surface;
wherein the iron core is manufactured by laminating a plurality of pole pieces having a fit portion formed on both sides, fixing the plurality of pole pieces to each other to form pole piece laminates, arranging a plurality of the pole piece laminates in a ring, holding the outer circumference or inner circumference thereof by jigs, and press-fitting connecting members in a laminating direction between adjacent portions of the plurality of adjoining pole piece laminates.
The connecting member is preferably made of a rigid material which is not deformed by press-fitting between adjoining pieces. More preferably, it may be made from a synthetic resin material or metallic material. The connecting member and the fit portion of the pole pieces are arranged such that they can be fitted to each other. For example, a protrusion may be formed in the connecting member and the fit portion may be recessed. Alternatively, a recess can be formed in the connecting member and the adjoining pole pieces contain a protrusion. If a jig is used, the jig preferably has a circular shape on the inner surface or the outer surface, and a recess may be formed in the inner surface of the jig to allow the pole piece outer tip portion to be fitted in order to improve positioning accuracy.
One of the characteristics of the invention is the step of holding the outer circumference or the inner circumference of a ring form pole piece laminate with a jig and then press-fitting a rigid connecting member between adjoining pole pieces at the fit portions. The fit portions are generally near the inner pole portion of the pole piece in the laminating direction. With this configuration, the pole piece laminates are accurately positioned and at the same time rigidly connected. However, it is sometimes troublesome to laminate disconnected pole pieces and to accurately arrange the pole pieces in the form of a ring. Therefore, connecting the pole pieces in the form of a ring in advance facilitates accurate lamination and ring formation. It is desirable that the connected pole pieces can be cut while maintaining the capabilities of the original stator itself. In the present invention, since the rigid connecting member is press-fitted, it is possible to break the connected form and separate the pole pieces from one another using the press-fit force. However, because the pole pieces are connected to one another in advance, the pole pieces are unable to be separated from one another at their position. Therefore, the pole pieces are advanced outwards in the radial direction by a specified distance and separated from one another by press-fitting the connecting member.
That is, the manufacturing process for a divided stator according to another embodiment of the invention comprises forming an iron core having outer circumferential slots by arranging a plurality of pole pieces having inner pole portions in a ring and connecting the inner pole portions of a plurality of adjoining pole pieces to one another;
winding coil around the outer circumferential slots of the iron core, and inserting the iron core into an outer ring yoke provided with a cylindrical inner surface;
wherein the iron core is manufactured by integrally forming an iron core blank comprising a plurality of pole pieces, arranging the pole pieces in a ring, wherein fit portions are formed on both sides of the pole pieces;
forming a bridge portion between the plurality of pole pieces adjacent to each other wherein the bridge portion can be broken by circumferential separation;
laminating and fixing a plurality of iron core blanks to form an iron core laminate, holding an outer circumference of the iron core laminate with a jig in such a manner that each pole piece advances outwards in a radial direction by a specified distance, breaking the bridge portion by separating the pole pieces in a circumferential direction while advancing each pole piece outwards in a radial direction by press-fitting a connecting member between fit portions of a plurality of adjacent pole pieces thereby connecting the adjacent pole pieces.
In order to break the bridge portion by press-fitting the connecting member, it is important that the width of the connecting member be greater than the distance between adjacent fit portions before press-fitting. It is also desirable to construct the jig in such a manner that the outer tip of the pole piece can advance outwards in the radial direction by a specified distance. For example, the inside diameter of the jig may be set slightly greater than the outside diameter of the iron core blank or the inside diameter of the jig may be set equal to or slightly smaller than the outside diameter of the iron core blank, and a fitting recess may be formed on the inner circumferential edge of the jig so that the outer tip of the pole piece can advance by a specified distance.
All the pole pieces are connected at a bridge portion and are use
Itoh Kazuo
Tachibana Toshiyuki
Bryant David P.
Itoh Electric Co. Ltd.
Kenny Stephen
Smith Patent Office
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