The present invention relates to a rotating electric machine.
In the related art, insulating sheets called slot liners are arranged in a slot of a stator of a rotating electric machine so as to cover a coil. Liquid varnish is permeated into the slot liner, the coil is fixed, and the coil is insulated.
JP 2018-78764 A (PTL 1) is a background art of the present technical field. JP 2018-78764 A describes “a motor stator in which an insulating sheet is disposed on slot wall surfaces of teeth of a stator core constituting a motor and a coil is formed around the teeth with the insulating sheet interposed therebetween. a recess portion and a protrusion portion that are continuous with each other are formed on at least one of a front surface of the insulating sheet close to the slot wall surface or a front surface close to the coil, the insulating sheet is fixed to the slot wall surface or the coil with an adhesive present at a tip of the protrusion portion interposed therebetween, and the recess portion is a cooling medium flow path.” (see ABSTRACT).
PTL 1: JP 2018-78764 A
However, in the related art (PTL 1), a gap (clearance) between a slot inner wall (stator core) and the coil is not considered. A fixing force of the coil in the slot is changed by the gap between the slot inner wall and the coil, and thus, there is a possibility that the coil vibrates unexpectedly in the stator core. Accordingly, there is a concern that the reliability of the rotating electric machine is influenced.
A typical example of the invention disclosed in the present application is as follows.
That is, a stator of a rotating electric machine includes a stator core on which teeth and slots are provided on a cylindrical inner surface, a plurality of windings arranged inside the slot, and slot liners disposed between an inner wall of the slot and the plurality of windings. Each of the plurality of windings has a first surface formed along a radial direction of the stator core and a second surface formed along a circumferential direction, the slot has a first inner wall facing the first surface, and a second inner wall facing the second surface, an adhesive layer expanded by processing is formed on a front surface of the slot liner, when an area of the first surface is larger than an area of the second surface, a distance between the first surface and the first inner wall is smaller than a distance between the second surface and the second inner wall, and when the area of the first surface is smaller than the area of the second surface, the distance between the first surface and the first inner wall is larger than the distance between the second surface and the second inner wall.
According to one aspect of the present invention, the coil is stably fixed, and the reliability of the rotating electric machine can be improved. Other objects, configurations, and effects will be made apparent in the following descriptions of the embodiments.
As illustrated in
Although not illustrated, the vehicle 100 has a battery that supplies a low voltage power (for example, 14-volt power) mounted thereon. A rotational torque due to the engine 120 and the rotating electric machines 200 and 201 is transmitted to front wheels 110 with a transmission 130 and a differential gear 140 interposed therebetween. The rotating electric machines 200 and 201 have the substantially configuration, and the rotating electric machine 200 will be representatively described below.
In
The rotating electric machine 200 is a three-phase synchronous motor with a built-in permanent magnet. The rotating electric machine 200 operates as an electric motor for rotating the rotor 400 by supplying a three-phase alternating current to the stator coil 510 wound around the stator core 305. When the rotating electric machine 200 is driven by the engine 120, the rotating electric machine operates as a generator and outputs a three-phase AC generated power. That is, the rotating electric machine 200 has both a function as an electric motor that generates a rotational torque by using electric energy and a function as a generator that generates a power by using mechanical energy, and can selectively use the above-described functions depending on a running state of the car.
The stator core 305 is formed by stacking a plurality of magnetic substances (for example, a plurality of electromagnetic steel plates) in an axial direction, and includes a yoke portion and a teeth portion (also referred to as a protrusion portion and a protrusion pole portion). The yoke portion includes a cylindrical yoke core 306 (also referred to as a core back) fitted to an inner peripheral side of the housing 205. The teeth portion includes a plurality of teeth cores 307 that protrude in a radial direction from an inner peripheral side of the yoke core 306 and is arranged in a circumferential direction at predetermined intervals. In
On the other hand, the rotor core 405 is formed by stacking a plurality of magnetic substances, for example, a plurality of electromagnetic steel plates in the axial direction. Rectangular magnet insertion holes 410 into which magnets are inserted are opened in the electromagnetic steel plates, and the permanent magnets 415 are embedded in the magnet insertion holes 410 and are fixed with an epoxy adhesive or the like. A width of the magnet insertion hole 410 in the circumferential direction is set to be larger than a width of the permanent magnet 415 in the circumferential direction, and magnetic gaps 416 are formed on both sides of the permanent magnet 415. The magnetic gaps 416 may be embedded with an adhesive, or may be integrally solidified with the permanent magnet 415 with a molding resin. The permanent magnets 415 act as field poles of the rotor 400.
A magnetizing direction of the permanent magnet 415 is oriented in the radial direction, and an orientation of the magnetizing direction is reversed for each field pole. That is, when a surface of a permanent magnet 415a close to the stator is an N pole and a surface thereof close to the axis is an S pole, a surface of an adjacent permanent magnet 415b close to the stator is an S pole and a surface thereof close to the axis is an N pole. These permanent magnets 415a and 415b are alternately arranged in the circumferential direction. The permanent magnet 415 may be embedded in the rotor core 405 after being magnetized, or may be magnetized by applying a strong magnetic field after being inserted into the rotor core 405 before being magnetized. The magnetized permanent magnet 415 is a strong magnet. When the magnet is magnetized before the permanent magnet 415 is fixed to the rotor 400, a strong attractive force is generated between the permanent magnet and the rotor core 405 when the permanent magnet 415 is fixed, and this attractive force hinders a work. There is a concern that dirt such as iron powder adheres to the permanent magnet 415 due to the strong attractive force. Thus, when the permanent magnet 415 is magnetized after being inserted into the rotor core 405, the productivity of the rotating electric machine is improved.
Neodymium-based or samarium-based sintered magnets, ferrite magnets, neodymium-based bonded magnets, and the like can be used as the permanent magnet 415. A residual magnetic flux density of the permanent magnet 415 is about 0.4 to 1.3 T.
The stator 300 of the rotating electric machine 200 is constituted by the cylindrical stator core 305 and the stator coil 510 and the slot liner 520 inserted into the stator core 305.
As illustrated in
The slot liners 520 are arranged in each slot 310. The slot liner 520 is, for example, an insulating sheet made of a heat-resistant resin, and has a thickness of about 0.1 to 0.5 mm. The slot liners 520 are arranged in the slot 310, and thus, a withstand voltage between the coils inserted into the slot 310 and between the coil and the inner surface of the slot 310 is improved. A required withstand voltage is retained even though an insulating film of the coil is deteriorated or damaged.
In the present embodiment, the slot liner 520 in which an adhesive layer is formed is used. For example, as illustrated in
For example, the slot liner is made by a sheet material in which a foam adhesive layer 522 having a thickness of 40 μm is formed on a base material 521 in which Nomex layers having a thickness of 50 μm are formed on both surfaces of a polyethylene naphthalate synthetic resin film having a thickness of 100 μm. Since a thickness of the foam adhesive expands up to about 3 times by heating, a thickness of the slot liner 520 increases from 280 μm to 440 μm in this example.
As illustrated in
Next, an example in which the segment coil 512 is disposed in the slot 310 will be described. In the embodiment of the present invention, the gap (clearance) between the stator coil 510 and the stator core 305 in the slot 310 is different in the circumferential direction and the radial direction of the stator core 305, and one gap is larger than the other gap. The insertability of the coil is improved. When this gap is increased, workability when the coil is inserted is improved, but a coil space factor decreases. Thus, the output characteristics of the rotating electric machine 200 decrease.
The foam adhesive layer is formed on the slot liner 520. The foam adhesive fills the gap between the inner wall of the slot 310 and the segment coil 512 due to the expansion of the foam adhesive by heating, and the segment coil 512 is fixed.
As described above, the segment coil 512 is constituted by the rectangular wires which have cross sections and have substantially parallel side surfaces. In the example illustrated in
At this time, an area of a first surface 514 which is a side surface of the segment coil 512 close to the long side of the rectangular wire is wider than an area of a second surface 516 which is a side surface of the segment coil 512 close to the short side of the rectangular wire, and the first surface faces a first inner wall 310A of the slot 310 with a large area. The slot liners 520 are arranged between the first surface 514 and the first inner wall 310A and between the second surface 516 and a second inner wall 310B. The slot liners 520 are also arranged between the segment coils 512. A distance between the first surface 514 of the segment coil 512 and the facing first inner wall 310A is smaller than a distance between the second surface 516 of the segment coil 512 and the facing second inner wall 310B.
In general, when the adhesive layer becomes thin, an adhesive force (for example, shear strength) of the adhesive is improved, and when an adhesive area becomes large, the adhesive force is improved. In particular, the adhesive force of the foam adhesive differs depending on the thickness after foaming (expansion ratio), and as the expansion ratio becomes smaller, a larger adhesive force is exhibited. In consideration of such characteristics, an optimum clearance and an expansion ratio are set by a contact area between the segment coil 512 and the slot liner 520.
The segment coil 512 vibrates in the slot 310 when an alternating current flows. Thus, when a fixing strength of the segment coil 512 in the slot 310 differs depending on a direction, abnormal vibration is likely to occur, and there is a concern that the rotating electric machine 200 is damaged. Thus, it is desirable that the fixing strength of the segment coil 512 in the slot 310 is larger in a direction in which a distance between the inner wall of the slot 310 and the segment coil 512 is smaller or is about the same in the circumferential direction and the radial direction of the stator core 305.
Thus, in the example illustrated in
As described above, the segment coil 512 is constituted by the rectangular wires which have cross sections and have substantially parallel side surfaces. In the example illustrated in
At this time, the area of the first surface 514 which is the side surface of the segment coil 512 on the long side of the rectangular wire is smaller than the area of the second surface 516 which is the side surface of the segment coil 512 on the short side of the rectangular wire, and the first surface faces the first inner wall 310A of the slot 310 with a small area. The slot liners 520 are arranged between the first surface 514 and the first inner wall 310A and between the second surface 516 and a second inner wall 310B. The slot liners 520 are also arranged between the segment coils 512. The distance between the first surface 514 of the segment coil 512 and the facing first inner wall 310A is larger than the distance between the second surface 516 of the segment coil 512 and the facing second inner wall 310B.
It is desirable that the fixing strength of the segment coil 512 in the slot 310 is about the same in the circumferential direction and the radial direction of the stator core 305 or increases in the direction in which the distance between the inner wall of the slot 310 and the segment coil 512 is small. Thus, in the example illustrated in
In the embodiment illustrated in
The foam adhesive layer 522 is formed on the slot liner 520, and thus, the coil can be fixed in the heating process. Accordingly, it is not necessary to apply varnish to the stator coil 510, and a manufacturing process of the stator 300 can be simplified.
Next, a modification example will be described. In the examples illustrated in
As described above, the segment coil 512 is constituted by the rectangular wires which have cross sections and have substantially parallel side surfaces. In the example illustrated in
As described above, in the embodiment illustrated in
As described above, the segment coil 512 is constituted by the rectangular wires which have cross sections and have substantially parallel side surfaces. In the example illustrated in
As described above, in the embodiment illustrated in
Next, an example of a shape of the slot liner 520 will be described. In the above-described embodiment, the slot liner 520 is formed in a so-called inverted B shape so as to wind each segment coil 512 with right ends of the surfaces on which two segment coils 512 surrounded by one slot liner 520 face as a start point and an end point. In this shape, all surfaces of the segment coil 512 are covered with the slot liner 520, and the slot liner 520 is also provided between the segment coils 512. Thus, high insulation and high coil fixing force can be obtained.
In the embodiment illustrated in
In the embodiment illustrated in
In the embodiment illustrated in
At the start point and the end point, the end portion of the slot liner 520 may overlap with another slot liner 520 as illustrated in the enlarged view. When the slot liner 520 is disposed such that the end portion overlap with the other portion, the gap is not generated in the slot liner 520, and thus, insulation performance can be improved. Although the slot liner 520 covers the space between the segment coil 512 and the inner wall of the slot 310, since the slot liner 520 is not provided between the segment coils 512, the coil fixing force is lower than that of the B shape or the S shape. However, the insertability of the segment coil 512 is improved, and the amount of the slot liner 520 used can be reduced.
The present invention is not limited to the aforementioned embodiments, and includes various modification examples and equivalent configurations within the gist of the appended claims. For example, the aforementioned embodiments are described in detail in order to facilitate easy understanding of the present invention, and the present invention is not limited to necessarily include all the described components. A part of the configuration of one embodiment may be replaced with the configuration of another embodiment. The configuration of another embodiment may be added to the configuration of one embodiment. Another configuration may be added, removed, and substituted to, from, and into some of the configurations of the aforementioned embodiments. REFERENCE SIGNS LIST
100 vehicle
110 wheel
120 engine
130 transmission
140 differential gear
150 battery
160 power conversion device
200 rotating electric machine
205 housing
210 end bracket
300 stator
305 stator core
306 yoke core
307 teeth core
310 slot
510 stator coil
512 segment coil
514 first surface
515 third surface
516 second surface
517 fourth surface
520 slot liner
Number | Date | Country | Kind |
---|---|---|---|
2018-188402 | Oct 2018 | JP | national |
Filing Document | Filing Date | Country | Kind |
---|---|---|---|
PCT/JP2019/034694 | 9/4/2019 | WO | 00 |