Rotary electric machine stator and manufacturing method therefor

A rotary electric machine stator according to the present invention includes: a frame that includes: a tube portion; and a flange portion that is disposed so as to be integrated with the tube portion so as to protrude radially outward from a first axial end of the tube portion; a stator core that is configured into an annular shape, and that is fitted together with and held inside the tube portion; coils that are mounted to the stator core; and a plurality of positioning members that are mounted to the flange portion so as to be movable radially and circumferentially around an axial center of the stator core.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a National Stage of International Application No. PCT/JP2016/083534 filed Nov. 11, 2016.

TECHNICAL FIELD

The present invention relates to a rotary electric machine stator for an electric motor, or a generator, etc., and to a manufacturing method therefor.

BACKGROUND ART

Conventional rotary electric machine stators have included: a plurality of split cores; an outer cylinder ring that fixes an outer circumferential side of the plurality of split cores so as to be arranged into an annular shape; and winding coils that are wound onto each of the split cores, the outer cylinder ring including a thin cylindrical tube portion; and fastening flanges that are respectively disposed so as flare outward from the tube portion, and that fix the stator by being fastened to an external housing or other devices (see Patent Literature 1, for example).

CITATION LIST

Patent Literature

SUMMARY OF THE INVENTION

Problem to be Solved by the Invention

In rotary electric machines of this kind, because a rotor is disposed on an inner circumferential side of the stator so as to ensure an extremely small gap away from the stator, it has been necessary to increase coaxiality of the stator and the rotor.

In conventional stators for rotary electric machines, because the split cores that are arranged into an annular shape are press-fitted into and fixed to the tube portion of the outer cylindrical ring, strain arises in the outer cylindrical ring. If parts such as an engine water jacket are fixed to the tube portion by welding, etc., strain due thereto also accumulates in the outer cylindrical ring. The fastening flanges are produced so as to be integrated with the tube portion, and constitute a portion of the outer cylindrical ring in which strain is accumulated. The outer cylindrical ring thereby deforms, making the positional relationship of the fastening portions of the fastening flanges relative to the axial center of the split cores that are arranged into the annular shape that is held by the outer cylindrical ring deteriorate. Thus, if the stator is mounted by fastening the fastening flanges to an external housing, the stator cannot be mounted to the external housing precisely. In other words, the central position of the stator cannot be positioned precisely at a set position. Coaxiality of the rotor and the stator thereby deteriorates in rotary electric machines that are produced by installing a rotor in an external housing.

The present invention aims to solve the above problems and an object of the present invention is to provide a stator for a rotary electric machine and a manufacturing method therefor in which a positioning member can be mounted to a frame so as to ensure high precision in a positional relationship of a positioning member relative to a stator core that is fitted together with and held by the frame, irrespective of deformation in the frame.

Means for Solving the Problem

A rotary electric machine stator according to the present invention includes: a frame that includes: a tube portion; and a flange portion that is disposed so as to be integrated with the tube portion so as to protrude radially outward from a first axial end of the tube portion; a stator core that is configured into an annular shape, and that is fitted together with and held inside the tube portion; coils that are mounted to the stator core; and a plurality of positioning members that are mounted to the flange portion so as to be movable radially and circumferentially around an axial center of the stator core.

Effects of the Invention

According to the present invention, positioning members are mounted to a flange portion so as to be movable radially and circumferentially around an axial center of a stator core. Thus, the positioning members can be moved and positioned at set positions in a circumferential direction and a radial direction around the axial center of the stator core after the stator core has been fitted together with and held inside a frame. Positional relationships between the stator core that has been fitted together with and held by the frame and the positioning members can thereby be ensured with high precision irrespective of deformation in the frame. Thus, if the stator that is configured in this manner is used, a rotary electric machine can be configured in which coaxiality between the rotor and the stator is increased.

DESCRIPTION OF EMBODIMENTS

FIG. 1is an oblique projection that explains a configuration of a rotary electric machine stator according to Embodiment 1 of the present invention.

InFIG. 1, a rotary electric machine stator1includes: a stator core2that is configured by arranging core segments3into an annular shape, the core segments3including: a circular arc-shaped core back3a; and a tooth3bthat protrudes radially inward from an inner circumferential surface of the core back3a; coils4that are wound onto the respective teeth3bof the core segments3; and a cylindrical frame5that fits together with and holds the stator core2that has been configured by arranging the core segments3into an annular shape in an internal portion by press-fitting.

The frame5includes: a cylindrical tube portion5a; a flange portion5bthat is formed around an entire circumference so as to protrude radially outward from a first axial end of the tube portion5a; and a plurality of fastening flange portions5cthat are disposed so as to be distributed circumferentially so as to each protrude radially outward from the flange portion5b. A fastening aperture6that functions as a fastening portion is formed on each of the fastening flange portions5c. In addition, mounting screw-threaded apertures7are formed on two positions of the flange portion5bthat face each other from opposite sides of the axial center of the tube portion5a. Moreover, the tube portion5a, the flange portion5b, and the fastening flange portions5care formed integrally using a metal such as iron, for example.

Positioning members8are produced using a thin steel plate, for example, and circular positioning apertures9, and mounting apertures10that have larger diameters than shaft portions of positioning screws16, are formed thereon.

A housing11is produced so as to have a cylindrical shape using a metal such as aluminum. A pair of positioning portions12are formed on a first end surface of the housing11so as to face each other from opposite sides of the axial center of the housing11. A second positioning aperture13is formed on each of the positioning portions12. Mounting portions14are formed on the first end surface of the housing11so as to correspond to each of the fastening flange portions5c. A mounting screw-threaded aperture15is formed on each of the mounting portions14

To assemble the stator1that is configured in this manner, eighteen core segments3, onto each of which a coil4is wound, are first arranged into an annular shape such that circumferential side surfaces of the core backs3aare butted against each other. Next, the group of core segments3that are arranged into the annular shape are press-fitted into the tube portion5aof the frame5. The stator core2that is formed into an annular shape using the core segments3is thereby fitted together with and held by the tube portion5a. Next, the positioning screws16are passed through the mounting apertures10, and are screwed into the mounting screw-threaded apertures7, to mount the positioning members8to the flange portion5b. Here, because the mounting apertures10are formed so as to have larger diameters than the shaft portions of the positioning screws16, the positioning members8are movable circumferentially and radially around the axial center of the stator core2. Then, the positioning members8are moved around the axial center of the stator core2such that aperture centers of the positioning apertures9are positioned at set circumferential positions and radial positions. Next, the positioning members8that have been positioned in this manner are fixed to the frame5by fastening the positioning screws16, to assemble the stator1.

Now, the mounting screw-threaded apertures7are formed on the flange portion5bsuch that the stator core2and the housing are coaxial when the frame5is mounted to the housing11. In other words, the circumferential positions and the radial positions of the centers of the positioning apertures9of the two positioning members8that are mounted to the flange portion5b, which are centered around the axial center of the tube portion5ain a state in which the stator core2has not been press-fitted therein, are aligned with the circumferential positions and the radial positions of the centers of the two positioning apertures13that are formed on the housing11, which are centered around the axial center of the housing11.

However, strain arises in the frame5due to press-fitting the stator core2into the tube portion5a, deforming the frame5. Center positions of the two positioning apertures9are displaced relative to center positions of the two positioning apertures13that are formed on the housing11by this deformation of the frame5. In Embodiment 1, the above-mentioned misalignment that results from the deformation of the frame5is compensated for by the positioning members8being moved around the axial center of the stator core2that is fitted together with and held by the frame5such that aperture centers of the positioning apertures9are positioned at the set circumferential positions and radial positions.

In a stator1that is assembled in this manner, the positioning members8are mounted to the housing11by placing the positioning apertures9and13on top of one another, and press-fitting positioning pins17into the positioning apertures9and13. The stator1is thereby housed inside the housing11in a state of being positioned with high precision, making the stator core2and the housing11coaxial. Next, the mounting screws18are passed through the fastening apertures6, and are fastened to the screw-threaded apertures15, to fix the fastening flange portions5cto the housing11. The stator1is thereby held firmly by the housing11in a state of being positioned with high precision.

According to Embodiment 1, the positioning members8are fixed so as to be movable in a radial direction and a circumferential direction by being fastened to the flange portions5bof the frame5into which the stator core2is fitted together and held by press-fitting. Thus, even if strain arises in the frame5due to the press-fitting of the stator core2, and the frame5deforms, the aperture centers of the positioning apertures9of the positioning members8can be positioned in set circumferential positions and radial positions that are centered around the axial center of the stator core2by loosening fastening of the positioning members8. In this manner, the positioning members8can be positioned relative to the stator core2with high precision irrespective of deformation of the frame5.

The stator1that is configured in this manner is mounted to the housing11by press-fitting the positioning pins17into the positioning apertures9and13of the positioning members8and the housing11. In addition, the stator1is housed and held inside the housing11coaxially by fastening mounting screws18that are passed through the fastening apertures6of the fastening flange portions5cinto the screw-threaded apertures15of the housing11. In other words, the stator1is housed and held inside the housing11in a state of being positioned with high precision. Thus, coaxiality between the rotor and the stator1is ensured in a rotary electric machine that uses the stator1, suppressing the generation of noise during driving, and also enabling extension of service life to be achieved.

The positioning members8have no function in fixing the stator1to the housing11, and only have a positioning function. Thus, because the rigidity of the positioning members8can be reduced compared to positions on the flange portion5bof the frame5that correspond to the mounting positions of the positioning members8, thin steel sheets can be used, enabling the positioning members8to be produced inexpensively.

Because the flange portion5bis formed so as to protrude radially outward from the first axial end of the tube portion5aaround the entire circumference, the rigidity of the frame5can be increased.

Moreover, in Embodiment 1 above, a flange portion is formed so as to protrude radially outward from a first axial end of a tube portion around an entire circumference, but a flange portion need only be formed at mounting positions of positioning members and positions of formation of fastening flange portions.

FIG. 2is a cross section that shows a rotary electric machine stator according to Embodiment 2 of the present invention.

InFIG. 2, a fastening aperture6that is formed on a fastening flange portion5cis formed so as to have a larger diameter than a first positioning aperture9that is formed on a positioning member8. The positioning member8is stacked on the fastening flange portion5c, and is fixed by being fastened to a flange portion5bof a frame5by a positioning screw16. Here, the first positioning aperture9is positioned inside the fastening aperture6when viewed from an axial direction of a stator core2.

Moreover, a remainder of the configuration is configured in a similar or identical manner to that of Embodiment 1 above.

In a stator1A that is configured in this manner, because the positioning member8is fixed by being fastened to the flange portion5bof the frame5so as to be movable radially and circumferentially, the positioning members8can be positioned relative to the stator core2with high precision irrespective of deformation of the frame5.

The stator1A is mounted to the housing11by press-fitting a bolt19that has high dimensional precision into the positioning apertures9and13, instead of a positioning pin17. Here, because the fastening aperture6is formed so as to have a larger diameter than the first positioning aperture9, and the first positioning aperture9is positioned inside the fastening aperture6when viewed from an axial direction of a stator core2, the bolt19can be passed through the first positioning aperture9and the fastening aperture6and be press-fitted into the second positioning aperture13.

Consequently, similar or identical effects to those in Embodiment 1 above can also be achieved in Embodiment 2.

According to Embodiment 2, because positioning by the positioning member8and fixing by the fastening flange portion5care performed at an identical position, space saving can be achieved. Because the positioning and the fixing relative to the housing11of the stator1A can be performed by the single bolt19, the number of parts can be reduced.

FIG. 3is a cross section that shows a rotary electric machine stator according to Embodiment 3 of the present invention.

InFIG. 3, a connection board unit20is disposed at a first axial end of a stator core2, and connects coils4to configure a desired alternating-current winding. Two brackets21protrude radially outward from different positions in a circumferential direction of the connection board unit20. Mounting apertures that have larger diameters than shaft portions of positioning screws16(not shown) are formed on the brackets21. Positioning apertures9are formed further outward on the brackets21than the mounting apertures.

Moreover, a remainder of the configuration is configured in a similar or identical manner to that of Embodiment 1 above.

In Embodiment 3, the connection board unit20is mounted to the first axial end of the stator core2that is fitted together with and held by the tube portion5aof the frame5by press-fitting. Although not shown, the positioning screws16are passed through the mounting apertures of the brackets21and fastened into the mounting screw-threaded apertures7that are formed on the flange portion5b. The aperture centers of the positioning apertures9of the brackets21are positioned in set circumferential positions and radial positions that are centered around the axial center of the stator core2by loosening fastening of the positioning screws16, moving the connection board unit20, and bending the brackets21. Next, the connection board unit20is fixed to the frame5by fastening the positioning screws16. The brackets21are thereby positioned relative to the stator core2with high precision. Next, the desired alternating-current winding is configured by connecting the coils4using the connection board unit20, to assemble a stator1B.

In the stator1B that is assembled in this manner, the brackets21are fixed to the housing11by placing the positioning apertures9and13on top of one another, and press-fitting positioning pins17into the positioning apertures9and13. The stator1B is thereby housed inside the housing11, making the stator core2and the housing11coaxial. Next, the mounting screws18are passed through the fastening apertures6, and are fastened to the screw-threaded apertures15, to fix the fastening flange portions5cto the housing11. The stator1B is thereby held firmly by the housing11in a state of being positioned with high precision.

In Embodiment 3, the brackets21can also be positioned relative to the stator core2with high precision irrespective of deformation of the frame5. Consequently, similar or identical effects to those in Embodiment 1 above can also be achieved in Embodiment 3.

According to Embodiment 3, because the brackets21for fixing the connection board unit20to the frame5also function as positioning members, the number of parts can be reduced.

Moreover, in Embodiment 3, positioning by the brackets21that also function as positioning members and fixing by the fastening flange portions5cmay be performed at identical positions in a similar or identical manner to Embodiment 2 above.

FIG. 4is a cross section that shows a rotary electric machine stator according to Embodiment 4 of the present invention.

InFIG. 4, a resolver22detects rotational frequency of a rotor and is disposed at a first axial end of the stator core2. Two brackets23protrude radially outward from different positions in a circumferential direction of the resolver22. Mounting apertures that have larger diameters than shaft portions of positioning screws16(not shown) are formed on the brackets23. Positioning apertures9are formed further outward on the brackets23than the mounting apertures.

Moreover, a remainder of the configuration is configured in a similar or identical manner to that of Embodiment 1 above.

In Embodiment 4, the resolver22is mounted to the first axial end of the stator core2that is fitted together with and held by the tube portion5aof the frame5by press-fitting. Although not shown, the positioning screws16are passed through the mounting apertures of the brackets23and fastened into the mounting screw-threaded apertures7that are formed on the flange portion5b. The aperture centers of the positioning apertures9of the brackets23are positioned in set circumferential positions and radial positions that are centered around the axial center of the stator core2by loosening fastening of the positioning screws16, moving the resolver22, and bending the brackets23. Next, the resolver22is fixed to the frame5by fastening the positioning screws16, to assemble a stator1C.

In the stator1C that is assembled in this manner, the brackets23are fixed to the housing11by placing the positioning apertures9and13on top of one another, and press-fitting positioning pins17into the positioning apertures9and13. The stator1C is thereby housed inside the housing11, making the stator core2and the housing11coaxial. Next, the mounting screws18are passed through the fastening apertures6, and are fastened to the screw-threaded apertures15, to fix the fastening flange portions5cto the housing11. The stator1C is thereby held firmly by the housing11in a state of being positioned with high precision.

In Embodiment 4, the brackets23can also be positioned relative to the stator core2with high precision irrespective of deformation of the frame5. Consequently, similar or identical effects to those in Embodiment 1 above can also be achieved in Embodiment 4.

According to Embodiment 4, because the brackets23for fixing the resolver22to the frame5also function as positioning members, the number of parts can be reduced.

Moreover, in Embodiment 4, positioning by the brackets23that also function as positioning members and fixing by the fastening flange portions5cmay be performed at identical positions in a similar or identical manner to Embodiment 2 above.

Moreover, in each of the above embodiments, positioning members that have reduced rigidity have been used, but positioning members that have greater rigidity due to increased thickness may be used. In that case, a function of fixing the stator to the housing may also be imparted, in addition to the positioning function, by forming fastening apertures on the positioning members, or by making the fastening apertures also function as positioning apertures. The fastening flange portion can thereby be omitted, enabling simplification of the configuration of the frame to be achieved.

In each of the above embodiments, two positioning members have been disposed on a frame that face each other from opposite sides of an axial center of a stator core, but the two positioning members need only be disposed on the frame so as to be separated in a circumferential direction. Furthermore, the number of positioning members may alternatively be three or more. In that case, the positioning members should be disposed so as to be distributed circumferentially, and it is particularly preferable for the positioning members to be arranged at a uniform angular pitch.

In each of the above embodiments, coils are constituted by concentrated winding coils that are wound onto core segments, but the coils may alternatively be distributed winding coils such as lap winding coils, wave-wound coils, etc.

In each of the above embodiments, a stator core is constituted by eighteen core segments, but the number of the core segments is not limited to eighteen.

In each of the above embodiments, a stator core is constituted by arranging core segments into an annular shape, but the stator core may be constituted by an annular integrated body.

In each of the above embodiments, core segments that are arranged into an annular shape are fitted together with and held by a tube portion of a frame by press-fitting, but the core segments that are arranged into the annular shape may be fitted together with and held by the tube portion of the frame by shrinkage-fitting.

EXPLANATION OF NUMBERING