Patent ID: 12212203

DESCRIPTION OF EMBODIMENT

As shown inFIG.1, a vehicle100of a hybrid vehicle has mounted thereon an engine120, a first rotating electrical machine200, a second rotating electrical machine201, and a high-voltage battery150. The battery150is constituted of a secondary battery such as a lithium-ion battery or a nickel-hydrogen battery and outputs direct-current power of 250 volts to 600 volts or more. In a case where driving force by the rotating electrical machines200and201is needed, the battery150supplies direct-current power to the rotating electrical machines200and201, and during regenerative traveling, the direct-current power is supplied from the rotating electrical machines200and201. The direct-current power between the battery150and the rotating electrical machines200and201is given and received via a power converter160.

In addition, in the vehicle100, an auxiliary battery which supplies low voltage power (for example, 14-volt system power) is mounted, though the auxiliary battery is not shown. Rotation torque by the engine120and the rotating electrical machines200and201is transmitted via a transmission130and a differential gear140to front wheels110. The rotating electrical machines200and201are configured to be substantially the same as each other, and hereinafter, the rotating electrical machine200will be described as a representative.

FIG.2is a schematic view showing the whole configuration of the rotating electrical machine200.

InFIG.2, one part of the rotating electrical machine200is shown in a cross-sectional view, thereby showing an inside of the rotating electrical machine200. As shown inFIG.2, inside a housing205, a stator300is supported, and the stator300has a stator core305and a stator coil510. On an inner peripheral side of the stator core305, a rotor400is rotatably supported via a gap500.

The rotor400has a rotor core405fixed to a shaft430, permanent magnets415, and a non-magnetic end plate420. The housing205has a pair of end brackets210for which bearings425and426are provided, and the shaft430is rotatably supported by the bearings425and426.

This rotating electrical machine200is a permanent magnet built-in type three-phase synchronous motor. By supplying a three-phase alternating current to the stator coil510which is wound around the stator core305, the rotating electrical machine200operates as an electric motor which rotates the rotor400. In addition, when the rotating electrical machine200is driven by the engine120, the rotating electrical machine200operates as a generator and outputs three-phase alternating current generated power. In other words, the rotating electrical machine200has both of a function as the electric motor which generates the rotation torque by using electric energy and a function as the generator which generates power by using mechanical energy and can selectively utilizes each of the above-mentioned functions depending on a traveling state of the vehicle.

FIG.3is a schematic view showing a cross-sectional view of the stator300and the rotor400, taken along line A-A shown inFIG.2and showing a cross-sectional view, taken along line A-A shown inFIG.2.FIG.4is a perspective view showing the stator core305with the coil attached andFIG.5is a plan view in which the stator core305with the coil attached is viewed from a coil end side. Note that inFIG.3, the housing205and the shaft430are not shown.

The stator core305is formed by laminating a plurality of magnetic bodies (for example, a plurality of magnetic steel sheets) in an axial direction and is constituted of a yoke part and tooth parts (also referred to as projecting parts or salient-pole parts). The yoke part is constituted of a cylindrical yoke core306(also referred to as a core back) which is fitted to an inner peripheral side of the housing205. The tooth parts are constituted of a plurality of tooth cores307which project from inner peripheral sides of the yoke core306in radial directions and are arranged at predetermined intervals in a circumferential direction. InFIG.3, all the teeth are not denoted by reference signs and only a part of the tooth cores307is denoted by a reference sign as a representative. Respectively neighboring tooth cores307are continuous in the circumferential direction and on a side of the rotor400, a plurality of slots310are formed. As shown inFIG.4, inside each of the slots310, slot insulation by a slot liner520is provided, and winding wires of a plurality of phases such as a U-phase, a V-phase, and a W-phase which constitute the stator300are attached. In the present embodiment, the stator coil510is wound by distributed winding. The stator coil510is constituted of a plurality of segment coils512.

On the other hand, the rotor core405is formed by laminating a plurality of magnetic bodies, for example, a plurality of magnetic steel sheets in an axial direction, in each of the magnetic steel sheets, a rectangular magnet insertion hole410into which a magnet is inserted is opened, and in the magnet insertion hole410, each of the permanent magnets415is embedded and is fixed by an epoxy-based adhesive or the like. A width of the magnet insertion hole410in a circumferential direction is set to be larger than a width of each of the permanent magnets415in a circumferential direction, and on both sides of each of the permanent magnets415, magnetic gaps416are formed. In these magnetic gaps416, an adhesive may be embedded, or these magnetic gaps416may be solidified integrally with the permanent magnets415by molding resin. The permanent magnets415act as field poles of the rotor400.

Magnetization directions of the permanent magnets415face in radial directions, and directions of the magnetization directions of the field poles are reversed. In other words, when side surfaces of the permanent magnets415aon a side of the stator are magnetized to N-poles and surfaces thereof on a side of the shaft are magnetized to S-poles, side surfaces of the neighboring permanent magnets415bon a side of the stator are magnetized to S-poles and surfaces thereof on a side of the shaft are magnetized to N-poles. These permanent magnets415aand permanent magnets415bare alternately arranged in a circumferential direction. The permanent magnets415may be embedded in the rotor core405after magnetization, or before the magnetization, the permanent magnets415are inserted into the rotor core405and thereafter, the permanent magnets415may be magnetized by giving a strong magnetic field thereto. The permanent magnets415after the magnetization are strong magnets, and when the magnets are magnetized before fixing the permanent magnets415to the rotor400, a strong attracting force is caused between the rotor core405and the permanent magnets415upon fixing the permanent magnets415and this attracting force disturbs work. In addition, it is likely that due to the strong attracting force, dust such as iron powder adheres to the permanent magnets415. Therefore, magnetizing after inserting the permanent magnets415into the rotor core405enhances productivity of the rotating electrical machine200.

As each of the permanent magnets415, a neodymium-based or samarium-based sintered magnet, a ferrite magnet, a neodymium-based bonded magnet, or the like can be used. A residual magnetic flux density of each of the permanent magnets415is approximately 0.4 to 1.3 T.

As shown inFIG.4, the stator300of the rotating electrical machine200is constituted of the cylindrical stator core305, and the stator coil510and the slot liners520, which are inserted into the stator core305.

In the slots310of the stator core305, the stator coil510is housed. In an example shown inFIG.4, each of the slots310is an open slot, and on an inner peripheral side of the stator core305, an opening to which the stator coil510is attached is formed.

Inside each of the slots310, the slot liner520is disposed. The slot liner520is, for example, an insulating sheet made of heat resistant resin and a thickness thereof is approximately 0.1 mm to 0.5 mm. In each of the slots310, the slot liner520is provided, thereby enhancing dielectric strength voltage in the coil inserted into the slots310and dielectric strength voltage between the coil and an inner surface of each of the slots310and retaining necessary dielectric strength voltage even when an insulating film of the coil is deteriorated or damaged.

FIG.6is a development view of a sheet material constituting the slot liner520andFIG.7is a cross-sectional view constituting the slot liner520.

In the present embodiment, used is the slot liner520in which on both surfaces of a first insulating substrate521, adhesive layers522are formed and on one surface thereof, a second insulating material layer523is provided. The slot liner520is constituted of a sheet material in which on both surfaces of the first insulating substrate521made of a synthetic resin film (for example, highly heat resistant resin such as polyethylene naphthalate), adhesive layers522made of a foaming adhesive are formed. Furthermore, the first insulating substrate521may be subjected to flame-retardant processing. For example, on both surfaces of the first insulating substrate521made of a heat resistant resin film, flame-retardant resin layers (for example, aramid resin such as Nomex (Nomex is a registered trademark)) may be provided, and on the flame-retardant resin layers, the adhesive layers522may be provided. As the first insulating substrate521, paper may be used, instead of the synthetic resin film.

By heating the foaming adhesive at a predetermined temperature for a predetermined period of time, the foaming resin expands and fills up gaps (clearances) between the stator coil510and inner walls of the slots310, thereby fixing the stator coil510to the stator core305. Note that an adhesive may be an adhesive whose volume increases by predetermined processing (for example, heating), instead of the foaming adhesive.

The second insulating material layer523may be formed by a synthetic resin film (for example, highly heat resistant resin such as polyethylene naphthalate), may be formed by a cloth-like sheet material made of synthetic resin fibers, or may be formed by applying synthetic resin onto the adhesive layers522. The second insulating material layer523may be constituted of a material different from a material of the first insulating substrate521or may be constituted of a same material as the material of the first insulating substrate521. For example, the first insulating substrate521may be formed by polyethylene naphthalate and the second insulating material layer523may be formed by Nomex. The second insulating material layer523is formed by Nomex, thereby allowing heat resistance and flame retardance of the slot liners520to be enhanced. In addition, the second insulating material layer523may be constituted of a material which is the same as the material of the first insulating substrate521(for example, polyethylene naphthalate). The second insulating material layer523is formed by polyethylene naphthalate, thereby allowing costs of the slot liners520to be reduced.

The second insulating material layer523is provided with through-holes524through which the expanded adhesive layers522can flow out. It is only required for one or more through-holes524to be provided, sizes thereof may be even or may be different from each other or one another, and shapes thereof may be various shapes such as a perfect circle, an ellipse, a square, and a rectangle. In other words, a number, a size, a shape of each of the through-holes524are not questioned, and representative examples of variation thereof will be described later with reference toFIGS.10to17.

FIG.8is a diagram showing the slot liner520and the segment coils512, which are attached to the stator core305, andFIG.9is a diagram showing the slot liner520and segment coils512, with the adhesive expanded.

When the slot liners520are inserted into the slots310, the slot liners520are arranged in such a way that the second insulating material layer523is located on an outer side close to inner walls of the slots310. Since the second insulating material layer523is provided on at least one surface of each of the slot liners520, no second insulating material layer523may be provided on an inner side which contacts the segment coils512. The through-holes524provided for the second insulating material layer523are gaps which communicate the first insulating substrate521with the inner walls of the slots310and through which the expanded adhesive layers522can flow out.

When the stator core305is heated after the segment coils512have been inserted into the slot liners520, the foaming adhesive of the adhesive layers522expands and flows through the through-holes524of the second insulating material layer523to outside the slot liners520, and a space between the stator core305and the segment coils512is filled with the adhesive.

In the slot liner520shown inFIGS.8and9, friction between the adhesive layers522and the stator core305is prevented by providing the second insulating material layer523on an outer side (a side opposite to the coil). However, the friction between the adhesive layers522and the segment coils512may be prevented by providing the second insulating material layer523on an inner side (a coil side), or the friction between the adhesive layers522and the stator core305and the friction between the adhesive layers522and the segment coils512may be prevented by providing the second insulating material layer523on both sides (the side opposite to the coil and the coil side).

For example, each of the slot liners520is formed by forming the adhesive layers522made of a 40 μm-thick foaming adhesive on the first insulating substrate521obtained by forming a 50 μm-thick Nomex layer on both surfaces of a 100 μm-thick polyethylene naphthalate synthetic resin film and by using a sheet material obtained by forming the second insulating material layer523made of a 50 μm-thick polyethylene naphthalate synthetic resin film. Since a thickness of the foaming adhesive expands approximately three times, in this example, a thickness of each of the slot liners520increases from 330 μm to 490 μm.

When the segment coils512and the slot liners520are located inside the slots310, gaps are provided between the segment coils512and the stator core305. Although when these gaps are made large, workability upon insertion is enhanced, a coil space factor is reduced and output characteristics of the rotating electrical machine200is thereby reduced. In addition, the gaps between the inner walls of the slots310and the stator coil510are filled with the foaming adhesive by the expansion of the adhesive layers522formed in the slot liners520, thereby fixing the stator coil510. If a gap is present between the stator core305and the stator coil510, the stator coil510vibrates inside the stator core305, thereby exerting influence on reliability of the rotating electrical machine200. In addition, if the adhesive of the adhesive layers522is scarce with respect to the gaps, an expansion coefficient of the adhesive increases, thereby making fixation of the stator coil510insufficient.

As shown inFIG.4, when the slot liners520are inserted into the slots310, a surface of each of the slot liners520and an inner wall of each of the slots310contact each other. When on the surface of each of the slot liners520, the adhesive layers522are exposed, the adhesive layers522may be shaved upon insertion into the slots310. When the adhesive layers522become thin, the fixation of the stator coil510becomes insufficient and the stator coil510vibrates inside the stator core305, thereby exerting influence on reliability of the rotating electrical machine200. Therefore, for the slot liners520in the present embodiment, the second insulating material layer523which covers the adhesive layers522is provided. The adhesive layers522and the inner walls of the slots310are made not to be rubbed with each other by the second insulating material layer523, thereby allowing peeling of the adhesive layers522caused by the friction on the surface of each of the slot liners520to be inhibited. Therefore, the gap between the stator coil510and the stator core305is filled with the expanded adhesive layers522at a desired expansion coefficient, thereby allowing vibration of the stator coil510due to a reduction in fixing strength of the adhesive to be inhibited and enabling reliability of the rotating electrical machine200to be enhanced. In addition, it is likely that the peeled adhesive turns into foreign matter and the foreign matter hinders assembly of the rotor400and the housing205in an assembly process of the rotating electrical machine200and causes hinderance of operation of the rotating electrical machine200.

Next, with reference toFIGS.10to17, a variety of variations of numbers, sizes, and shapes of the through-holes524will be described.

A through-hole524of the slot liner520shown inFIG.10is constituted of one perfect circle. In addition, through-holes524of the slot liner520shown inFIG.11are constituted of a large perfect circle and small perfect circles, a number of the large perfect circle and a number of the small perfect circles are different from each other, and in a configuration shown inFIG.11, one large perfect circle and four small perfect circles are provided. In addition, through-holes524of the slot liner520shown inFIG.12are constituted of a plurality of small perfect circles, and in a configuration shown inFIG.12, eight perfect circles are provided. Through-holes524of the slot liner520shown inFIG.13are constituted of a plurality of ellipses, and in a configuration shown inFIG.13, four ellipses are provided. Through-holes524of the slot liner520shown inFIG.14are constituted of a plurality of squares whose directions and sizes are different from each other, and although in a configuration shown inFIG.14, numbers and arrangement of different kinds of squares are the same as each other, the numbers and the arrangement may be different from each other.

Each of the slot liners520is molded to be of a three-dimensional shape so as to allow each of the segment coils512to be inserted thereinto. Therefore, a planar insulating substrate is bent to form the three-dimensional shape. Through-holes524of the slot liner520shown inFIG.15are constituted of a plurality of rectangles, and a long side of each of the rectangles is provided in a direction of each of creases525of the slot liner520(preferably, in parallel with each of the creases525). As described above, the through-holes524are formed by the rectangles, each of which is long in a direction of each of the creases525of the slot liner520(an insertion direction of each of the segment coils512), thereby allowing strong adhesion force by the expanded adhesive layer523to be obtained.

Through-holes524of the slot liner520shown inFIG.16are constituted of a plurality of rectangles, and a long side of each of the rectangles is provided in such a way as to intersect with each of creases525of the slot liner520(preferably, in such a way as to be perpendicular to each of the creases525).

A second insulating material layer523of the slot liner520shown inFIG.17is formed by a fiber material, and through-holes524are gaps which are formed by fibers constituting the fiber material in a lattice-like or mesh-like manner.

As described above, the shape of each of the through-holes524may be any shape such as the perfect circle or perfect circles, the ellipses, the squares, and the rectangles shown in the drawings, and a plurality of shapes may be combined. In addition, a size of each of the through-holes524may be any size, and through-holes524having a plurality of sizes may be combined.

Note that the present invention is not limited to the above-described embodiment and various modifications and equivalent configurations coming within the meaning of the scope of the appended claims are embraced. For example, the above-described embodiment is described in details in order to facilitate understanding of the present invention, and the present invention is not necessarily limited to an embodiment which includes all the described configurations. In addition, a part of a configuration of a certain embodiment may be replaced with a configuration of other embodiment. In addition, a configuration of other embodiment may be added to a part of a configuration of a certain embodiment. In addition, as to a part of configurations of embodiments, addition, deletion, and replacement of other configurations may be made.

REFERENCE SIGNS LIST

100vehicle110wheel120engine130transmission140differential gear150battery160power converter200rotating electrical machine205housing210end bracket300stator305stator core306yoke core307tooth core310slot510stator coil512segment coil520slot liner521first insulating substrate522adhesive layer523second insulating material layer