WO2015087128A2

WO2015087128A2 - Insulator and stator

Info

Publication number: WO2015087128A2
Application number: PCT/IB2014/002692
Authority: WO
Inventors: Masashi Matsumoto; Tetsushi MIZUTANI; Yuichiro Ito
Original assignee: Toyota Motor Corp
Current assignee: Toyota Motor Corp
Priority date: 2013-12-13
Filing date: 2014-12-08
Publication date: 2015-06-18
Anticipated expiration: 2016-06-13
Also published as: WO2015087128A3; JP2015116104A; JP5991308B2

Abstract

An insulator is placed between an axial end face of a stator core and a stator coil wound around a plurality of teeth of the stator core. The teeth are extended in a radial direction of the stator core. The insulator includes a plurality of tooth cover portions, and an outer rib portion. The plurality of tooth cover portions is placed on the teeth of the stator core. The plurality of tooth cover is extended in the radial direction. The outer rib portion connects outer ends of the plurality of tooth cover portions to each other. The outer rib portion includes at least two positioning portions that position the insulator. The positioning portions are placed on an outer peripheral side of the outer rib portion in the radial direction. The positioning portions are placed at a regular interval in a circumferential direction of the outer rib portion.

Description

INSULATOR AND STATOR

BACKGROUND OF THE INVENTION

1 . Field of the Invention

[0001] The present invention relates to an insulator that can be easily positioned at the time of manufacture of a stator, and a stator using the insulator.

2. Description of Related Art

[0002] A stator of a motor is configured such that a stator coil is wound around teeth of a stator core. Here, a resin (plastic) insulator having a shape corresponding to the teeth of the stator core is placed on a motor-axial end surface of the teeth of the stator core, so to ensure insulation to the stator coil wound around the teeth.

[0003] For example, Japanese Patent Application Publication No. 2007-312549 (JP 2007-3 12549 A) proposes that a width of an insulator in its circumferential direction is set larger than that of a tooth of a stator core, so as to protect a coil wound around the tooth. That is, the insulator placed in a tooth end face projects toward slots of the stator core, so that the stator coil wound around the tooth makes contact with the resin insulator, rather than the metal tooth. This makes it possible to prevent an insulating coating of the stator coil from being damaged to cause dielectric breakdown.

SUMMARY OF THE INVENTION

[0004] In JP 2007-3 12549 A, a projection having a width corresponding to the slot of the stator core is provided on an inner peripheral side of the insulator, so that the insulator is positioned hereby. However, it is difficult to sufficiently increase dimension accuracy of the width of the slot and the width of the projection of the insulator, which causes poor assembly of the insulator in the cause of mass production. Further, the stator coil is wound in a state where the insulator is placed on an end surface of the stator core. In this case, a segment-shaped coil is inserted into the slot between the teeth of the stator core and is twisted with the insulator being as a fulcrum. This may cause such a problem that the projection is broken by a stress due to the twisting or the projection slides over a side surface of the tooth and is worn out due to friction, thereby causing misalignment of the insulator.

[0005] The present invention provides an insulator and a stator each of which prevents misalignment of the insulator effectively.

[0006] An insulator according to a first aspect of the present invention to be placed between an axial end face of a stator core and a stator coil wound around a plurality of teeth of the stator core. The teeth are extended in a radial direction of the stator core. The insulator includes a plurality of tooth cover portions, and an outer rib portion. The plurality of tooth cover portions is placed on the teeth of the stator core. The plurality of tooth cover portions is extended in the radial direction. The outer rib portion connects outer ends of the plurality of tooth cover portions to each other. The outer rib portion includes at least two positioning portions that position the insulator. The positioning portions are placed on an outer peripheral side of the outer rib portion in the radial direction. The positioning portions are placed at a regular interval in a circumferential direction of the outer rib portion.

[0007] In the insulator according to the first aspect of the present invention, each of the positioning portions may be a projection provided in an outer circumference of the outer rib portion. A width of the projection may be decreased from a base portion of the projection toward a tip end thereof. Further, each of the positioning portions may be a notch provided in an outer circumference of the outer rib portion. A width of the notch may be decreased from a base portion of the notch toward a tip end thereof.

[0008] A stator according to a second aspect of the present invention includes a stator core, a stator coil, and an insulator. The stator core includes a plurality of teeth. The teeth are extended in a radial direction of the stator core. The stator coil is wound around the teeth. The insulator is placed between an axial end face of the stator core and the stator coil. The insulator includes a plurality of tooth cover portions, and an outer rib portion. The plurality of tooth cover portions is placed on the teeth of the stator core. The plurality of tooth cover portions is extended in the radial direction. The outer rib portion connects outer ends of the plurality of tooth cover portions to each other. The outer rib portion includes at least two positioning portions that position the insulator. The positioning portions are placed on an outer peripheral side of the outer rib portion in the radial direction. The positioning portions are placed at a regular interval in a circumferential direction of the outer rib portion.

[0009] In the present invention, the positioning portions are provided in the insulator, thereby making it possible to effectively prevent misalignment of the insulator. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Features, advantages, and technical and industrial significance of exemplary embodiments of the invention will be described below with reference to the accompanying drawings, in which like numerals denote like elements, and wherein:

FIG. 1 is a perspective view of an insulator according to one embodiment;

FIG. 2 is a magnified view of a positioning portion;

FIG. 3A is a plane view of an insulator provided with two positioning portions on upper and lower sides thereof;

FIG. 3B is a plane view of an insulator provided with three positioning portions on an upper side, a lower left side, and a lower right side thereof;

FIG. 3C is a plane view of an insulator provided with four positioning portions on upper and lower sides and right and left sides thereof;

FIG. 4A is a view illustrating a relationship between a pin and a positioning portion using a V-shaped notch;

FIG. 4B is a view illustrating a relationship between a pin and a positioning portion using an arc recess with a flat bottom face;

FIG. 4C is a view illustrating a relationship between a pin and a positioning portion using a trapezoidal projection;

FIG. 5 is a view illustrating a configuration of the stator core;

FIG. 6 is a view illustrating a winding state of the stator core to a tooth; and FIG. 7 is a view illustrating an exemplary configuration of a segment.

DETAILED DESCRIPTION OF EMBODIMENTS

[0011] The following describes an embodiment of the present invention with reference to drawings. Note that the present invention is not limited to the embodiment described herein.

[0012] FIG. 1 is a perspective view illustrating an appearance of an insulator 10 according to one embodiment. As illustrated herein, a plurality of tooth cover portions 12 extended radially is provided at a regular interval. The tooth cover portion 12 is placed on each tooth of a stator core and has a plane shape similar to the tooth of the stator core. In this example, a width of the tooth cover portion 12 is widened outwardly in a radial direction. Further, the tooth cover portion 12 is configured such that four corners of its sectional shape are chamfered, a bottom face thereof is placed on the tooth of the stator core, and the bottom face has a width equivalent to the tooth. Accordingly, the tooth cover portion 12 slightly projects toward slots of the stator core, and an opening 14 formed in a gap between the tooth cover portions 12 in a circumferential direction is smaller than the slot of the stator core. Since upper comers of the tooth cover portion 12 are chamfered, a stator coil is easy to be wound around it. Further, the tooth cover portion 12 serves as a fulcrum at the time when the stator coil is twisted. In view of this, the tooth cover portion 12 has strength to some extent, and has a thickness of a few mm or more, e.g., 5 to 6 mm.

[0013] A toric outer rib portion 16 is placed on an outer peripheral side of the tooth cover portions 12, and outer ends of the tooth cover portions 12 are connected thereto. The outer rib portion 16 is placed on a plane of an outer peripheral side of the stator core. Because of this, its bottom face is placed on the same plane as the tooth cover portions 12. The stator coil is not wound around the outer rib portion 16, so that its thickness is a few mm, which is thinner than the tooth cover portions 12.

[0014] A toric inner rib portion 18 is placed on an inner peripheral side of the tooth cover portions 12, and inner ends of the tooth cover portions 12 are connected thereto. A top face of the inner rib portion 18 is placed on the same plane as the tooth cover portions 12, and has a thickness of a few mm, similarly to the outer rib portion 16.

[0015] The insulator 10 is made of an insulating material, which is generally resin, and is fonned by injection molding using a mold.

[0016] As described above, the tooth cover portions 12, the outer rib portion 16, and the inner rib portion 18 are fonned separately, and then connected to each other. However, they are fonned integrally in general. Note that, circular recesses existing on surfaces of the tooth cover portions 12 and the outer rib portion 16 are recesses fomied by ejector pins.

[0017] Further, in the present embodiment, a positioning portion 20, which is a

V-shaped notch fonned inwardly from a radial outside, is provided on an outer circumference of the outer rib portion 16. Accordingly, by engaging a pin or the like provided axially in a stator to the positioning portion 20, the insulator 10 can be positioned. That is, the insulator 10 can be positioned by engaging, to the positioning portion 20, a pin extending axially to be engaged from outside.

[0018] In this example, positioning portions 20 are provided at two places separated by 180 degrees in an axially symmetric manner. Note that the positioning portions 20 may be provided at three or more places, provided that they are separate d at a regular interval along the outer circumference. Further, the positioning portions 20 are placed on a radial outside of the outer rib portion 16. Accordingly, even if the positioning portions 20 are provided, the insulator 10 can maintain sufficient strength. That is, if the positioning portion 20 is provided on an outer side of the opening 14, the positioning portion 20 is provided in that part of the insulator 10 which is relatively weak. Particularly, in a case where the positioning portion 20 is a notch, the strength of the outer rib portion 16 provided with the positioning portion 20 becomes very weak. When the positioning portion 20 is placed on an outer side of the outer rib portion 16, the tooth cover portions 12 can receive a force applied to the positioning portion 20, thereby making it possible to maintain sufficient strength of the insulator 10. Particularly, when the positioning portions 20 are provided at a regular interval in the circumferential direction, it is possible to distribute a stress effectively by evenly dividing a force applied to the outer rib portion 16.

[0019] FIG. 2 is a schematic view of a part A in FIG. 1. As illustrated herein, the positioning portion 20 is formed in such a manner that the outer rib portion 16 is dented, and the positioning portion 20 is placed outside the tooth cover portion 12.

[0020] FIGS. 3 A to 3C are plane views of the insulator 10 and illustrate positions where the positioning portions 20 are provided. FIGS. 3A to 3C illustrate examples where the positioning portions 20 are provided at two places, three places, and four places, respectively. In FIG. 3 A, the positioning portions 20 are provided at two places on upper and lower sides in the figure. In FIG. 3B, the positioning portions 20 are provided at three places on an upper side, a lower left side, and a lower right side in the figure, and in FIG. 3C, the positioning portions 20 are provided at four places on upper and lower sides and right and left sides in the figure.

[0021] FIGS. 4A to 4C illustrate a state where a positioning pin 30 is engaged with the positioning portion 20, and illustrate the positioning portions 20 having different shapes. The positioning pin 30 is provided as a part of a motor manufacturing device (jig), is placed to fix the insulator 10 after the insulator 10 is fixed with a stator core. That is, a pair of insulators 10 is placed (or temporarily fixed) on an upper side and a lower side of a cylindrical stator core and is supported by a supporting material in that state, while the insulators 10 are pushed from outside by the positioning pins 30 so as to be positioned.

[0022] FIG. 4A illustrates an example in which a V-shaped notch as illustrated in FIGS. 1 to 3 is employed as the positioning portion 20. The positioning portion 20 is formed by denting (cutting) an end of the insulator 10 in a V-shape. Hereby, a width of the V-shaped notch is decreased from a base portion of the notch toward a tip thereof. The tip of the V-shape faces toward a center of the insulator 10. Then, a columnar positioning pin 30 extending in an axial direction of the stator is pushed against such a positioning portion 20 so as to make contact with both sides of the positioning portion 20 from outside. Accordingly, the positioning pin 30 makes contact with the insulator 10 at two points in its circumferential direction, and pushes the insulator 10 toward its center, thereby positioning the insulator 10. In FIG. 4 A, a gap is formed between a bottom portion of the positioning pin 30 and a bottom portion of the positioning portion 20. A plurality of positioning portions 20 is placed in a surrounding part of the insulator 10 at a regular interval, and forces received by all the positioning portions 20 from their corresponding positioning pins 30 serve as a force to fix the insulator 10 so that the center of the insulator 10 does not move.

[0023] Further, the tip (bottom) of the V-shaped recess is chamfered to be round, so that a stress is prevented from being concentrated thereon. Further, the positioning pin 30 is configured to make contact with both sides of the positioning portion 20, thereby making it possible to surely perform positioning with the positioning pin 30 as a simple round bar.

[0024] FIG. 4B illustrates an example in which an arc recess having a flat bottom face is provided as the positioning portion 20. In this example, a sectional shape of the positioning pin 30 is a shape obtained by linearly cutting part of a circle, so as to have a flat surface by cutting a side part of a round bar, as a whole. The flat surface portion of the positioning pin 30 is pushed against the insulator 10 so as to face the bottom face of the positioning portion 20. Accordingly, side surfaces around the bottom face of the positioning pin 30 are pushed against those side portions of the positioning portion 20 which are close to the bottom face, so that the insulator 10 is positioned. Even in this example, a connection portion between the bottom of the positioning portion 20 and both side portions thereof is chamfered to be round, so that a stress is prevented from being concentrated thereon.

[0025] FIG. 4C illustrates an example in which a trapezoidal projection is provided as the positioning portion 20. A width of the projection is decreased from a base portion of the projection towards a tip end thereof. In this example, two round bar-shaped positioning pins 30 are pushed against both sides of the trapezoidal positioning portion from outside, so that the insulator 10 is positioned. Even in this example, a connection portion between the projection of the positioning portion 20 and both side portions thereof is chamfered to be round, so that a stress is prevented from being concentrated thereon.

[0026] FIG. 5 illustrates a partial configuration of a stator core 40. The stator core 40 is constituted by a cylindrical core portion 42 that is cylindrical as a whole, and a plurality of teeth 44 placed at a regular interval in a circumferential direction and extending inwardly (toward a center) from the core portion 42. Each gap between the plurality of teeth 44 is a slot 46. A coil is inserted into the slot and is wound around the tooth 44, so as to form the stator core. Note that, there are two methods as a method of coil winding, i.e., concentrated winding in which a coil is wound around one tooth 44, and distributed winding in which a coil is wound around a plurality of teeth, either of which is applicable to the present embodiment.

[0027] FIG. 6 is a schematic view of a stator in a state where a coil is wound around a teeth, viewed from a central side. The tooth cover portion 12 of the insulator 10 is placed in an upper end of the tooth 44, and a stator coil 50 is wound around the tooth via the insulator 10. This example shows distributed winding, and the stator coil 50 extended from the left direction is inserted into a slot on the right side of the tooth 44 along the tooth cover portion 12, and the stator coil 50 going outside from a slot on the left side extends toward the right direction. A lower side of the stator is configured in the same manner.

[0028] A circumferential width of the tooth cover portion 12 of the insulator 10 is wider than a width of the tooth 44. Accordingly, the stator coil 50 is separated from side walls of the tooth 44, so that the stator coil 50 is more surely insulated from the tooth 44. Further, a section of the tooth cover portion 12 is formed in a square or a rectangular shape close to a square, and has sufficient strength. Further, comers of the tooth cover portion 12 are chamfered, so that the stator coil 50 can be easily wound around it. Note that the insulators 10 are placed both on an upper side and a lower side of the stator core.

[0029] FIG. 7 illustrates an example of a segment 52 of the stator coil 50. As illustrated herein, the segment has a U-shape. The segment 52 is inserted into the slot 46 as illustrated in FIG. 5, and an end of the segment 52 is bent with the insulator 10 as a fulcrum in the circumferential direction, so as to be connected, by welding or the like, to a bent end of another segment 52. By repeating this process, the stator coil 50 is wound around the teeth 44, and thus, the stator core 40 is formed.

[0030] In the present embodiment, the insulator 10 is attached to the stator core 40, and is fixed to an assembly device (jig) in that state. Then, the insulator 10 is positioned by the positioning pins 30. In that state, the segments 52 are inserted into the slots 46 sequentially, so as to wind the stator coil 50 around the teeth 44. At this time, since the insulator 10 is fixed to the stator core 40 by the positioning pins 30, the stator coil 50 can be surely wound around the teeth 44 without misaligning the insulator 10 from the stator core 40. Particularly, the insulator 10 has the positioning portions 20, thereby making it possible to easily fix the insulator 10 by the positioning pins 30.

Claims

CLAIMS:

1. An insulator to be placed between an axial end face of a stator core and a stator coil wound around a plurality of teeth of the stator core, the teeth being extended in a radial direction of the stator core, the insulator comprising:

a plurality of tooth cover portions placed on the teeth of the stator core, the tooth cover portions being extended in the radial direction; and

an outer rib portion that connects outer ends of the plurality of tooth cover portions to each other, the outer rib portion including at least two positioning portions that position the insulator, the positioning portions being placed on an outer peripheral side of the outer rib portion in the radial direction, the positioning portions being placed at a regular interval in a circumferential direction of the outer rib portion.

2. The insulator according to claim 1 , wherein:

each of the positioning portions is a projection provided in an outer circumference of the outer rib portion, and

a width of the projection is decreased from a base portion of the projection toward a tip end of the projection.

3. The insulator according to claim 1 , wherein:

each of the positioning portions is a notch provided in an outer circumference of the outer rib portion, and

a width of the notch is decreased from a base portion of the notch toward a tip end of the notch.

4. A stator comprising:

a stator core including a plurality of teeth, the teeth being extended in a radial direction of the stator core;

a stator coil wound around the teeth; and an insulator placed between an axial end face of the stator core and the stator coil, the insulator including a plurality of tooth cover portions and an outer rib portion, the plurality of tooth cover portions being placed on the teeth of the stator core, the tooth cover portion being extended in the radial direction, the outer rib portion connecting outer ends of the plurality of tooth cover portions to each other, the outer rib portion including at least two positioning portions that position the insulator, the positioning portions being placed on an outer peripheral side of the outer rib portion in the radial direction, the positioning portions being placed at a regular interval in a circumferential direction of the outer rib portion.