Insulating member and stator

An insulator is provided between a stator core and a conductive wire provided on the stator core. The insulator includes a wound portion, around which the conductive wire is wounded, having a substantially rectangular shape; and a flange, formed in the axial end of the wound portion in the stator tooth tip side, for pressing the conductive wire in the axial direction (radial direction relative to the rotation axis of a rotor in a configuration of a rotating electrical machine). The flange includes four corner portions at its four corners, and intermediate portions formed between the four corner portions to have a width (B2) narrower than the width (B1) of the four corner portions. In addition, the flange has a tip with a curved shape.

TECHNICAL FIELD

The present invention relates to an insulating member and a stator, in particular, to an insulating member positioned between a core body and a coil provided on the core body, and a stator having the insulating member.

BACKGROUND ART

An insulating member provided between a core body and a coil has been known conventionally. For example, Japanese Patent Laying-Open 2005-323477 (Patent Document 1) describes a motor including a core member having a bobbin, made of a resin, around which a winding wire is wound and a plurality of teeth to which the bobbin is attached; and a circumferentially extending tooth bar provided in the tip of each of the teeth. The tooth bar therein is formed integrally with the bobbin and is attached to the tooth together with the bobbin.

Further, Japanese Utility Model Laying-Open 62-12907 (Patent Document 2) describes a coil bobbin having a flange with a notched portion.

Furthermore, Japanese Patent Laying-Open 59-43775 (Patent Document 3) describes a winding frame having a flange with a thickness getting thinner as it extends from its root to its tip.

The bobbin in Patent Document 1 has a complex shape, so dimensional control may be difficult. From another point of view, due to the bobbin having such a complex shape, the resin for forming the bobbin is less likely to flow into some portions in the mold during the molding of the bobbin. Deficiency in the molding is concerned. The above-mentioned problems are not sufficiently solved by the configurations described in Patent documents 2, 3 necessarily.

DISCLOSURE OF THE INVENTION

It is an object of the present invention to provide an insulating member and a stator having the insulating member, which achieve improved dimensional control/formability of the insulating member while securing a retention capability for a coil.

An insulating member according to the present invention is provided between a core body and a coil provided on the core body. The insulating member includes a wound portion, around which the coil is wound, having a substantially rectangular shape; and a flange, formed at an axial end of the wound portion, for pressing the coil in an axial direction (radial direction relative to the rotation axis of a rotor in a configuration of a rotating electrical machine).

In one aspect, in the insulating member, the flange has four corner portions at its four corners and intermediate portions that are formed between the four corner portions to have a width narrower than a width of each of the four corner portions. In this aspect, the corner portions provided in the four corners secure a retention capability for the coil, and the area of the flange is limited to narrow an area of deformation of the insulating member, thereby facilitating dimensional control.

In other aspect, in the insulating member, the flange has a tip with a curved shape. In this aspect, the flange secures a retention capability for the coil, and during molding of the insulating member, with the tip of the flange having the curved shape, a resin for forming the insulating member readily flows into a portion corresponding to the tip of the flange to improve formability of the insulating member.

It is preferable that, in the insulating member, the flange be formed to have a thickness getting thinner as the flange extends from its root to its tip. The tip of the flange, which is a free end, can secure required strength even though the thickness thereof is thinner than the root of the flange. Due to the flange getting thinner as it extends from its root to its tip as described above, the usage amount of the material for forming the insulating member can be reduced, resulting in reduction of manufacturing cost of the insulating member and weight reduction of the insulating member.

It is preferable that, in the insulating member, the wound portion be provided with a void. With this, the usage amount of the material for forming the insulating member can be reduced. Further, heat conduction from the coil to the core body is attained not only via the insulating member. This allows improved heat conductivity between the coil and the core body.

A stator according to the present invention includes a stator tooth; a stator coil wound around the stator tooth; the above-described insulating member provided between the stator tooth and the stator coil; and a resin portion formed on the stator coil and the insulating member.

According to the above configuration, in one aspect, the area of the flange of the insulating member is limited, so a stator allowing for high efficiency of heat transfer from the stator coil to the resin portion is provided. Meanwhile, in another aspect, the tip of the flange of the insulating member has a curved shape to relieve stress concentration, in the mold resin portion molding the stator coil and insulating member, at a portion located in the vicinity of the tip of the flange. Accordingly, a stator is provided in which occurrence of cracking in the mold resin portion is restrained. Furthermore, during molding of the mold resin portion, the flow of the mold resin is facilitated at the tip of the flange. Accordingly, a stator allowing for high formability of the mold resin portion is provided.

As one example, in the stator, the stator coil and the insulating member are attached to the stator tooth such that the flange is positioned adjacent to a tip of the stator tooth.

According to the present invention, the retention capability for the coil and the dimensional control/formability of the insulating member can be attained at the same time.

It should be noted that two or more of the above configurations may be combined appropriately.

BEST MODES FOR CARRYING OUT THE INVENTION

An embodiment of the present invention will be described below. Note that the same or equivalent portions are given the same reference characters and explanation therefor may not be repeated.

When reference is made to a number, an amount, and the like in the embodiment described below, the scope of the present invention is not necessarily limited by the number, the amount, and the like unless otherwise noted. Further, in the below-described embodiment, each component is not necessarily essential for the present invention unless otherwise noted. Furthermore, if there are a plurality of embodiments below, it is initially expected to combine respective features of the embodiments, unless otherwise noted.

FIG. 1shows a hybrid vehicle (HV), which serves as an “electrically powered vehicle”, including a stator according to one embodiment of the present invention. In the specification of the present application, the “electrically powered vehicle” is not limited to the hybrid vehicle but includes, for example, a fuel cell vehicle and an electric car.

Referring toFIG. 1, the hybrid vehicle includes a stator10, a rotor20, a shaft30, a speed reducing mechanism40, a differential mechanism50, a drive-shaft receiving unit60, a PCU (Power Control Unit)70, and a battery80, which is a chargeable/dischargeable secondary battery.

Stator10and rotor20constitute a rotating electrical machine (motor generator) having a function as an electric motor or an electric generator. Rotor20is attached to shaft30. Shaft30is rotatably supported by a housing of a driving unit via a bearing.

Stator10has a ring-shaped stator core. The stator core is constructed by stacking plate-like magnetic bodies of, for example, iron or an iron alloy. On the inner circumferential surface of the stator core, there are formed a plurality of stator teeth and slot portions formed between the stator teeth and each serving as a recess. The slot portions are provided to be open in the inner circumferential side of the stator core.

Around the teeth, stator coils including winding wires of three phases, a U-phase, a V-phase, and a W-phase, are wound to fit in the slot portions. The coils of the U-phase, the V-phase, and the W-phase are wounded to be offset on the circumference of the stator core. The stator coils are connected to PCU70via a feeder cable. PCU70is electrically connected to battery80via a feeder cable. Thus, battery80and the stator coils are electrically connected.

The motor generator including stator10and rotor20outputs motive power, which is then transmitted from speed reducing mechanism40to drive-shaft receiving unit60via differential mechanism50. The driving force transferred to drive-shaft receiving unit60is transmitted as rotating force to a vehicular wheel (not shown) via a drive shaft (not shown), thus allowing the vehicle to travel.

Meanwhile, upon regenerative braking of the hybrid vehicle, the vehicular wheel is rotated by inertial force of the vehicular body. The vehicular wheel gives rotating force to drive the motor generator, via drive-shaft receiving unit60, differential mechanism50, and speed reducing mechanism40. On this occasion, the motor generator operates as an electric power generator. The electric power generated by the motor generator is stored in battery80via an inverter provided within PCU70.

FIGS. 2,3are perspective views showing stator10(FIG. 2shows it before formation of a mold resin whereasFIG. 3shows it after the formation of the mold resin).FIG. 4is a cross sectional view of stator10. Referring toFIGS. 2-4, stator10includes stator core110, the stator coils, bus bars to which the stator coils are connected, a terminal module1to which the bus bars are attached, a mold resin portion120, a connector portion130, and insulators140each serving as an “insulating member”.

First U-phase coil11U is constructed by winding a conductive wire511U around a tooth. Conductive wire511U has one end connected to a first U-phase coil terminal4111U, and the other end thereof is connected to a first U-phase coil terminal1111U.

First V-phase coil11V is constructed by winding a conductive wire511V around a tooth. Conductive wire511V has one end connected to a first V-phase coil terminal1211V, and the other end thereof is connected to a first V-phase coil terminal2111V.

First W-phase coil11W is constructed by winding a conductive wire511W around a tooth, Conductive wire511W has one end connected to a first W-phase coil terminal2211W, and the other end thereof is connected to a first W-phase coil terminal3111W.

Second U-phase coil12U is constructed by winding a conductive wire512U around a tooth. Conductive wire512U has one end connected to a second U-phase coil terminal3212U, and the other end thereof is connected to a second U-phase coil terminal4112U.

Second V-phase coil12V is constructed by winding a conductive wire512V around a tooth. Conductive wire512V has one end connected to a second V-phase coil terminal3212V, and the other end thereof is connected to a second V-phase coil terminal1212V.

Second W-phase coil12W is constructed by winding a conductive wire512W around a tooth. Conductive wire512W has one end connected to a second W-phase coil terminal3212W, and the other end thereof is connected to a second W-phase coil terminal2212W.

Third U-phase coil13U is constructed by winding a conductive wire513U around a tooth. Conductive wire513U has one end connected to a third U-phase coil terminal3313U, and the other end thereof is connected to a third U-phase coil terminal1313U.

Third V-phase coil13V is constructed by winding a conductive wire513V around a tooth. Conductive wire513V has one end connected to a third V-phase coil terminal3313V, and the other end thereof is connected to a third V-phase coil terminal2313V.

Third W-phase coil13W is constructed by winding a conductive wire513W around a tooth. Conductive wire513W has one end connected to a third W-phase coil terminal3313W, and the other end thereof is connected to a third W-phase coil terminal3413W.

Fourth U-phase coil14U is constructed by winding a conductive wire514U around a tooth. Conductive wire514U has one end connected to a fourth U-phase coil terminal1314U, and the other end thereof is connected to a fourth U-phase coil terminal1114U.

Fourth V-phase coil14V is constructed by winding a conductive wire514V around a tooth. Conductive wire514V has one end connected to a fourth V-phase coil terminal2314V, and the other end thereof is connected to a fourth V-phase coil terminal2114V.

Fourth W-phase coil14W is constructed by winding a conductive wire514W around a tooth. Conductive wire514W has one end connected to a fourth W-phase coil terminal3414W, and the other end thereof is connected to a fourth W-phase coil terminal3114W.

As shown inFIGS. 2,4, each of the coil terminals is provided to protrude from a rail100. The terminal has a recess that receives its corresponding conductive wire to secure connection between the conductive wire and the terminal. Each coil is wound around an insulator140to form a cassette coil, and then the cassette coils thus formed are installed in stator core110.

In manufacturing stator10, terminal module1is first installed on the axial end surface of stator core110formed by stacking electromagnetic steel plates. Then, the cassette coils formed by winding the coils around insulators140are fit into the teeth of stator core110. Thereafter, mold resin portion120described below is formed.

Referring toFIGS. 3,4, the rail and the coils provided on stator core110are molded by mold resin portion120constituted by a resin. This secures positioning of each of the coils and insulation between neighboring coils. Note that such molding using a resin is not limited to the one for forming a molded body as shown inFIGS. 3 and 4. An insulating resin such as varnish may be applied to surfaces of the coils to secure positioning of each coil.

FIG. 5schematically shows respective connections of the bus bars in terminal module1.FIG. 6is a cross sectional view showing rail100included in terminal module1.

Referring toFIGS. 5,6, rail100is provided with a plurality of grooves100A,100B,100C,100D arranged from the inner circumferential side to the outer circumferential side of rail100. Note that each of grooves100A,100B,100C,100D has an interrupted shape.

The bus bars include first bus bars11-13, second bus bars21-23, third bus bars31-34, and a fourth bus bar41.

First bus bars11,12,13are fit into groove100A. First bus bar11is provided with first U-phase coil terminal1111U and fourth U-phase coil terminal1114U. In addition, first bus bar11has a connector terminal130U installed therein. Electric power from connector terminal130U is supplied to first bus bar11. First bus bar12is provided with first V-phase coil terminal1211V and second V-phase coil terminal1212V. First bus bar13is provided with third U-phase coil terminal1313U and fourth U-phase coil terminal1314U.

Second bus bars21,22,23are fit into groove100B. Second bus bar21is provided with first V-phase coil terminal2111V and fourth V-phase coil terminal2114V. In addition, second bus bar21has a connector terminal130V installed therein. Electric power from connector terminal130V is supplied to second bus bar21. Second bus bar22is provided with first W-phase coil terminal2211W and second W-phase coil terminal2212W. Second bus bar23is provided with third V-phase coil terminal2313V and fourth V-phase coil terminal2314V.

Third bus bars31,32,33,34are fit into groove100C. Third bus bar31is provided with fourth W-phase coil terminal3114W and first W-phase coil terminal3111W. In addition, third bus bar31has a connector terminal130W installed therein. Electric power from connector terminal130W is supplied to third bus bar31. Third bus bar32is provided with second U-phase coil terminal3212U, second V-phase coil terminal3212V, and second W-phase coil terminal3212W. Third bus bar33is provided with third U-phase coil terminal3313U, third V-phase coil terminal3313V, and third W-phase coil terminal3313W. Third bus bars32,33serve as neutral points connecting the U-phase, V-phase, and W-phase coils. Third bus bar34is provided with third W-phase coil terminal3413W and fourth W-phase coil terminal3414W.

Fourth bus bar41is fit into groove100D. Fourth bus bar41is provided with first U-phase coil terminal4111U and second U-phase coil terminal4112U.

FIG. 5shows a three-phase alternating-current motor of a star connection. However, the present invention is not limited to this and is applicable to, for example, a three-phase coil motor of a delta connection. Further, in the example ofFIG. 5, the U-phase, V-phase, W-phase bus bars are arranged in this order when viewed in the radially inward direction, but the positions of the U-phase and W-phase bus bars may be interchanged for example.

FIG. 7is a perspective view showing a cassette coil according to the present embodiment. In addition,FIG. 7shows an insulator140viewed from the inner circumferential side of stator core110. As shown inFIG. 7, the cassette coil is formed by winding a conductive wire510around insulator140. Insulator140includes a wound portion141around which conductive wire510is wound, and a flange142A for pressing conductive wire510to prevent deformation in the winding. As shown inFIG. 7, flange142A, which is located in the inner circumferential side of stator core110, has notches in its straight portion, apart from its four corners. In other words, flange142A has four corner portions143A and intermediate portions144A located between corner portions143A. Each of corner portions143A has a width (B1) wider than the width (B2) of each of intermediate portions144A. Further, flange142A has a rounded tip surface145A. Namely, in the cross section of flange142A, the tip of flange142A has a curved shape.

FIG. 14is a perspective view showing a cassette coil according to a comparative example. Referring toFIG. 14, the cassette coil according to the comparative example is formed by winding a conductive wire5100around an insulator1400. Insulator1400includes a wound portion1410, around which conductive wire5100is wound, having a substantially rectangular shape, and a flange1420for pressing conductive wire5100to prevent deformation in the winding.

In the comparative example ofFIG. 14, flange1420is formed to have a width that circumferentially entirely covers conductive wire5100and no notched portion is provided unlike in the example ofFIGS. 7,8. A flange is a portion that is likely to have deformation, such as warping, during molding of insulator1400. Hence, when flange1420is large as in the comparative example, an area of deformation will be large, which may make dimensional control difficult. In addition, flange1420circumferentially entirely covering conductive wire5100limits improvement of efficiency of heat transfer from conductive wire5100to the mold resin portion. Further, since flange1420is large, insulator1400is likely to have a great influence (occurrence of thermal stress, cracking in the resin, and the like) over its surrounding resin due to a difference in a linear expansion coefficient when providing the mold resin portion.

On the contrary, in the present embodiment, in flange142A located in the inner circumferential side of stator core110, intermediate portions144A each having a width narrower than those of corner portions143A are provided. Hence, flange142A is small and conductive wire510has portions not covered with flange142A. With flange142A being small, the usage amount of the resin, which is a raw material for forming insulator140, can be reduced to achieve reduction of manufacturing cost of insulator140and weight reduction of insulator140. Further, such a small flange142A facilitates dimensional control of insulator140. Further, the influence of insulator140over mold resin portion120caused by the difference in the linear expansion coefficient can be advantageously reduced. Furthermore, since conductive wire510has the portions not covered with flange142A, conductive wire510and mold resin portion120are in direct contact with each other in a larger area, thereby improving efficiency of heat transfer from conductive wire510to mold resin portion120.

Deformation in winding of conductive wire510is likely to occur in the corner portions of conductive wire510, rather than in straight portions thereof. Therefore, the width of each of corner portions143A over the corner portions of conductive wire510is relatively widened and the width of each of intermediate portions144A over the straight portions of conductive wire510is relatively narrowed, to secure a retention capability for conductive wire510while attaining the above-mentioned advantage.

In the example ofFIG. 7, the width (B) of each of corner portions143A in an oblique direction is approximately 15 mm but may be further narrowed (to, for example, approximately 2 mm) as long as strength required for a flange can be secured.

Referring toFIG. 14again, in the comparative example, flange1420has a planar end surface1450and has a tip with an angular portion. During molding of insulator1400, a molten material (containing a resin dissolved therein) is less likely to flow into the angular portion, with the result that deficiency in molding is likely to occur in this portion. In addition, due to such an angular tip of flange1420, stress concentration is likely to occur in the mold resin portion that surrounds flange1420.

In contrast, in the present embodiment, since tip surface145A of flange142A is rounded, flow of a molten material containing the resin for forming insulator140is facilitated during molding of insulator140to achieve improved formability of insulator140. Also, stress concentration is relieved in mold resin portion120located in the vicinity of the tip of flange142A. Further, during molding of mold resin portion120, flow of a molten material containing a resin for forming mold resin portion120is facilitated on tip surface145A to achieve improved formability of mold resin portion120.

FIG. 8is a perspective view of the cassette coil shown inFIG. 7, when viewed from the back surface side thereof (the outer circumferential side of stator core110). Referring toFIG. 8, also in the back surface side of the cassette coil, a flange142B is provided to prevent deformation in the winding of conductive wire510. Flange142B has first portions1421B axially protruding together with an coil end from the axial end surfaces of the opposite sides of the stator core, and second portions1422B making contact with stator core100. Each of first portions1421B has a tip surface1451B that is rounded as with tip surface145A of flange142A. Each of second portions1422B is formed to be thinner than first portion1421B as described below, and has a tip surface1452B that is not rounded typically. Note that, in flange142B, notched portions1420B are provided only in upper and lower first portions1421B. No notched portion is provided in second portions1422B making direct contact with stator core110at the slot portion.

FIG. 9is a cross sectional view taken along a line IX-IX inFIG. 7. Referring toFIG. 9, flange142A is formed to be thinner in a tapered manner as it extends from its root to its tip. The tip of flange142A, which is a free end, can secure required strength even though the thickness thereof is thinner than the root of flange142A. Due to flange142A getting thinner as it extends from its root to its tip as shown inFIG. 9, the usage amount of the resin for forming insulator140can be further reduced, resulting in further reduction of manufacturing cost of insulator140and further weight reduction of insulator140.

Note that in the example ofFIGS. 7-9, the thickness of flange142A (in the root) is, for example, approximately 2 mm, the thickness of each of first portions1421B of flange142B is, for example, approximately 2 mm, and the thickness of each of second portions1422B of flange142B is, for example, approximately 0.5 mm. Namely, flange142A is formed to be thicker than second portions1422B of flange142B.

The thickness of each of flanges142A,142B is appropriately changed. Further, the portions to be rounded in flanges142A,142B are also appropriately changed.

Note that flange142A may be shaped so that only one side of tip surface145A is rounded as shown inFIG. 10. In the example ofFIG. 10, the side making contact with conductive wire510(the lower side thereof inFIG. 10) is not rounded. However, the side making contact with conductive wire510may be rounded and the other side (the upper side inFIG. 10) may not be rounded.

Next, referring toFIGS. 11-13, variations of insulator140will be described.FIG. 12shows an insulator140shown inFIG. 11, when viewed in the direction of an arrow B. As shown inFIGS. 11,12, insulator140has a wound portion141in which a hole portion146serving as a “void” is formed. During molding of mold resin portion120, the resin for forming mold resin portion120flows into hole portion146. By forming hole portion146, the usage amount of the resin for forming insulator140can be reduced. Further, via not only insulator140but also the mold resin having flowed thereinto, heat can be conducted from conductive wire510to stator core110. This allows improved heat conductivity between conductive wire510and stator core110.

It should be noted that a hole portion146similar to the above-described one is also formed in insulator140on a surface seen when viewed in the direction of an arrow A (the upper surface thereof inFIG. 11).

FIG. 13shows a variation of insulator140shown inFIG. 11when viewed in the same direction. As shown inFIG. 13, instead of hole portion146, slit portions147may be provided.

In summary, the above description is as follows. That is, insulator140according to the present embodiment serving as an “insulating member” is provided between stator core110and conductive wire510(511U-514U,511V-514V,511W-514W) provided on stator core110. Insulator140includes wound portion141, around which conductive wire510is wounded, having a substantially rectangular shape; and flange142A, formed in the axial end of wound portion141in the stator tooth tip side, for pressing conductive wire510in the axial direction (radial direction relative to the rotation axis of the rotor in the configuration of the rotating electrical machine). Flange142A includes four corner portions143A at its four corners, and intermediate portions144A formed between four corner portions143A to have a width (B2) narrower than the width (B1) of four corner portions143A. In addition, flange142A has a tip with a curved shape.

Although the embodiments of the present invention have been described, it should be considered that the embodiments disclosed herein are illustrative and non-restrictive in any respect. The scope of the present invention is defined by the scope of claims, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

INDUSTRIAL APPLICABILITY

The present invention is applicable to, for example, a stator of a rotating electrical machine installed in a hybrid vehicle, and an insulating member included in the stator.