JP7702082B2 - Stator, rotating electric machine, and method for manufacturing stator - Google Patents

Description

The present invention relates to a stator, a rotating electric machine, and a method for manufacturing a stator.

In electric motors and generators used in EVs (electric vehicles) and PEVs (plug-in electric vehicles), a large current flows through the stator winding, so rectangular wires (rectangular conductors) with a large cross-sectional area are used as the conductors for the stator winding. As a result, the connection units containing the rectangular wires become larger and interfere with the peripheral components of the motor, so there is a demand for technology to compactly house the connection units near the motor.

In light of this situation, a method is known in conventional rotating electric machines in which rectangular wire is arranged in multiple layers axially outward of the coil ends of the stator winding to make the wiring unit more compact.

Patent No. 6610249

Electric motors and generators used in EVs (electric vehicles) and PEVs (plug-in electric vehicles) require vibration resistance in particular. Conventionally, the stator windings are wound using rectangular wire, and in order to ensure vibration resistance, the stator windings are fixed with varnish.

However, when using varnish to bond the windings together, there was a possibility that reliability would be reduced, especially at the coil ends, due to variations in the varnish's penetration and adhesion.

The object of the present invention is to provide a stator, a rotating electric machine, and a method for manufacturing a stator that can stably fix coil ends and ensure reliable vibration resistance.

In order to achieve the above-mentioned object, a stator according to an embodiment of the present invention comprises a cylindrical stator core having a plurality of stator slots formed in the circumferential direction on an inner peripheral surface thereof, a plurality of coil segments each having a straight portion with a rectangular cross section partially received in each of two different stator slots and an end portion with a rectangular cross section connecting the two straight portions at an outer side of a first end portion in the axial direction of the stator core, and a plurality of jumper portions connecting the plurality of coil segments in series at an outer side of a second end portion in the axial direction of the stator core, the stator winding including, for each phase, a plurality of jumper portions each including a coil end portion that is an outer portion of the first end portion of the stator winding and that is adjacent to each other in the radial direction and an adhesive insulating portion interposed in at least a portion of the radially adjacent portions that contact each other, the adhesive insulating portion being formed by disposing and adhering a foamed adhesive sheet, the foamed adhesive sheet having a planar base material and a foamed adhesive layer applied to both sides of the base material, the straight portions of each of which are accommodated in each of the stator slots form a plurality of layers in the radial direction, the radially adjacent portions are bonded to each other by the adhesive insulating portion , and the adhesive insulating portion is disposed at every other radial position between portions of the straight portions of each of the layers in the coil end portion .

1 is a vertical cross-sectional view showing an example of a rotating electric machine having a stator according to an embodiment; 1 is a partial cross-sectional view showing an example of a rotating electric machine according to an embodiment; FIG. 4 is a three-dimensional view for explaining a coil end of a stator according to the embodiment. FIG. 4 is a three-dimensional view showing a conceptual arrangement of adhesive insulating portions at a coil end of a stator according to an embodiment. FIG. 4 is a vertical cross-sectional view showing a foam adhesive sheet used to fix a coil end of a stator according to the embodiment. FIG. 4 is a flow chart showing the steps of a method for manufacturing a stator according to the embodiment. FIG. 4 is a conceptual perspective view illustrating the use of a coil end holding jig in the manufacturing method of the stator according to the embodiment.

Hereinafter, a stator, a rotating electric machine, and a method for manufacturing a stator according to an embodiment of the present invention will be described with reference to the drawings. Hereinafter, identical or similar parts will be given common reference numerals and duplicate explanations will be omitted.

Figure 1 is a longitudinal cross-sectional view showing an example of a rotating electric machine 1 having a stator 100 relating to an embodiment.

The rotating motor 1 comprises a rotor 10, a bearing 21, a bearing bracket 22, a frame 23, and a stator 100.

The rotor 10 has a rotor shaft 11 extending in the direction of the central axis of rotation CL, a rotor core 12 attached radially outward of the rotor shaft 11, permanent magnets 13 embedded in the rotor core 12, and stop plates 14 provided at both axial ends of the rotor core 12 to prevent the permanent magnets 13 from protruding. The rotor shaft 11 is rotatably supported by bearings 21 on both axial ends. Each bearing 21 is supported stationary by a bearing bracket 22.

The stator 100 has a stator core 110 arranged radially outside the rotor core 12 with a gap therebetween, and a stator winding 120 partially housed within a stator slot 111 (Figure 2) formed in the stator core 110 and wound around stator teeth 112 (Figure 2).

The stator 100 is housed within a frame 23 arranged to surround the radially outer side and is supported stationary by the frame 23.

The stator winding 120 has a plurality of coil segments 130 and a plurality of transition sections 125 that connect the coil segments 130. The coil segments 130 and the transition sections 125 are made of rectangular conductors 121.

Here, the coil segment 130 has two straight sections 131 that are respectively housed in two different stator slots 111, and a connection section 132 that connects these two straight sections 131 on the axial outside of the first end 110a of the stator core 110. Each straight section 131 is housed in a stator slot 111, and both ends of the straight section 131 protrude axially outside the first end 110a and second end 110b of the stator core 110.

A jumper portion 125 connects each of the straight portions 131 of the coil segments 130 protruding axially outward from the second end portion 110b.

Figure 2 is a partial cross-sectional view showing an example of a rotating electric motor 1 relating to an embodiment.

A plurality of stator slots 111, which are axial through grooves spaced apart from one another in the circumferential direction, are formed on the radial inner surface of the stator core 110. The stator slots 111 are also formed adjacent to one another in the circumferential direction to form stator teeth 112.

In each stator slot 111, a plurality of rectangular conductors 121, which are the straight portions 131 of the coil segments 130, are stacked in the radial direction while being electrically insulated from each other. That is, as shown in FIG. 2, in each stator slot 111, the first layer conductor 131a, the second layer conductor 131b, the third layer conductor 131c, the fourth layer conductor 131d, the fifth layer conductor 131e, and the sixth layer conductor 131f are arranged in this order from the outside to the inside in the radial direction. Hereinafter, regardless of the stator slot 111, these rectangular conductors 121, which are the straight portions 131, will be referred to as the first layer conductor 131a, the second layer conductor 131b, the third layer conductor 131c, the fourth layer conductor 131d, the fifth layer conductor 131e, and the sixth layer conductor 131f in the order of the layers.

Figure 3 is a three-dimensional diagram illustrating the coil ends of the stator 100 of the embodiment.

The coil segments 130 are housed in stator slots 111 between stator teeth 112 formed on the inner circumferential surface of the stator core 110, and have straight sections 131 partially protruding from the end of the stator core 110, and connection sections 132 connecting the straight sections 131. The coil end refers to the portion of the stator winding 120 consisting of the protruding portion of the straight section 131 from the first end 110a of the stator core 110 and the connection section 132. In other words, the coil end is the portion of the stator winding 120 that is axially outward of the first ends 110a of all the coil segments 130.

With regard to the straight portion 131, within each stator slot 111, the leftmost side in FIG. 3 is the first layer, and the rightmost side, i.e., the side closest to the inner circumferential surface, is the sixth layer.

Figure 4 is a three-dimensional diagram showing the conceptual arrangement of adhesive insulating parts 142 in the coil end 120a of the stator 100 according to the embodiment. Figure 4 shows the content shown in Figure 3 with the adhesive insulating parts 142 added, and shows the coil end 120a of the stator 100 according to the present embodiment.

The adhesive insulating portion 142 includes a first adhesive insulating portion 142a shown by a solid line and a second adhesive insulating portion 142b shown by a dashed line. Positions on the cylindrical curved surface that are the same distance from the central axis of rotation CL are referred to as having the same radial position or as being radial positions.

The first adhesive insulating portion 142a is arranged in the axial direction at a position that is visible from the axial end face of the coil end 120a. The first adhesive insulating portion 142a is arranged at or near the radial positions between the second and third layers, the fourth and fifth layers, the sixth and seventh layers, and the seventh and eighth layers.

In addition, the second adhesive insulating portion 142b is located in the axial direction at a portion where the coil end has a lane change (a portion where layers change), and the vicinity of this portion is not directly visible from the end face in the axial direction. It is located at or near the radial position between the first and second layers, and the radial position between the third and fourth layers.

Therefore, the adhesive insulating portion 142, i.e., the first adhesive insulating portion 142a and the second adhesive insulating portion 142b, are both arranged between the flat rectangular conductors 121 adjacent to each other in the radial direction.

Here, as long as the vibration resistance of the coil end 120a is ensured, the adhesive insulating portion 142 does not need to be disposed over the entire circumference, but may be disposed partially in the circumferential direction. It is also not necessary to dispose it between all layers. For example, it may be disposed every other layer.

As described later, the adhesive insulating portion 142 is formed by foaming and adhering the foam adhesive sheet 141 (FIG. 5) set in that position by raising the temperature. The foam adhesive sheet 141 becomes the adhesive insulating portion 142, and each part of the coil end 120a is adhered and fixed to each other.

Figure 5 is a longitudinal cross-sectional view showing a foam adhesive sheet 141 used to fix the coil ends of a stator in accordance with an embodiment of the present invention.

The foamed adhesive sheet 141 has a planar base material 141a and a foamed adhesive layer 141b applied to both sides of the base material 141a. The base material 141a is, for example, a film made mainly of polymeric materials. The foamed adhesive layer 141b foams and adheres when the temperature is increased. The adhesive insulating part 142 shown in Figure 3 foams and adheres when the foamed adhesive sheet 141 becomes hot during the stator assembly process.

Figure 6 is a flow chart showing the steps of a method for manufacturing a stator according to an embodiment.

First, multiple coil segments 130 and multiple interposed foam adhesive sheets 141 are stacked sequentially in a coil end holding jig (step S01).

Figure 7 is a conceptual oblique view illustrating the use of a coil end holding jig in a stator manufacturing method according to an embodiment.

The coil end holding jig 200 has an inner cylinder 201, an outer cylinder 202, and a bottom 203 that connects the lower end of the inner cylinder 201 to the lower end of the outer cylinder 202. That is, as shown in FIG. 7, the coil end holding jig 200 is a container having an annular storage space 205, in which the inner cylinder 201 and the outer cylinder 202 are arranged concentrically.

The storage space 205 is formed with dimensions capable of storing the coil end 120a protruding axially from the first end 110a of the stator core 110.

In step S01, for example, as shown in Figure 7, each coil segment 130 is placed in order on the bottom 203 of the coil end holding jig 200 with the connection portion 132 of the coil segment 130 facing downward and the straight portion 131 facing vertically upward. At this time, foam adhesive sheets 141 are sandwiched in necessary places.

Specifically, coil segment 130a of coil segment 130, foam adhesive sheet 141, and coil segment 130b of coil segment 130 are installed in the circumferential direction on the radially inner side, and the installation range is gradually expanded radially outward. In order to stably install each coil segment 130 on bottom portion 203, coil end holding jig 200 is provided with receivers for each coil segment 130, but these are not shown in the figure.

In this way, the entire coil segment 130, with the foamed adhesive sheet 141 sandwiched between as needed, is placed on the coil end holding jig 200. As a result, the straight portion 131 of each coil segment 130 extends vertically upward with the coil end 120a facing downward.

Next, the stator core 110 is lowered from above toward the coil end holding jig 200 with the first end 110a facing down, and each straight section of the connecting section is inserted into each stator slot (step S02). As a result, the straight section 131 of each coil segment 130 protrudes from the second end 110b of the stator core 110.

Next, a foam adhesive sheet is inserted radially between each coil segment 130 protruding from the second end 110b of the stator core 110 (step S03).

Next, the straight portions 131 of the coil segments 130 protruding from the second end 110b of the stator core 110 are bent, and the straight portions 131 are connected to each other (step S04). As a result, the stator winding 120 is wound around the stator core 110. In addition, the straight portions 131 of a given coil segment 130 are connected to the neutral point, and external terminals are attached to the straight portions 131 of a given coil segment 130.

Next, the stator 100 with the stator winding 120 wound around the stator core 110 is heated (step S05). Here, the heating is performed at a temperature at which the foamed adhesive sheet 141 foams and exhibits its adhesive function, and at the lowest possible temperature. This is to prevent any influence on the insulating members (not shown) other than the foamed adhesive sheet 141. As a result, the foamed adhesive layer 141b of the foamed adhesive sheet 141 foams and becomes the adhesive insulating portion 142. In this way, two coil segments 130 with adjacent portions are adhered to each other via the base material 141a, and are electrically insulated from each other by the base material 141a.

Next, other components are attached (step S06).

By following the above steps, the foam adhesive sheet 141 can be installed at any desired location.

In the above embodiment, for the rectangular conductor 121 in the straight portion 131 in the stator slot 111, an insulating portion is formed by attaching the slot insulating paper 145 to the rectangular conductor 121 in the straight portion 131 before inserting it into the stator slot 111. At this time, if the slot insulating paper 145 is simply insulating paper, varnish is placed between the slot insulating paper 145 and the winding. On the other hand, if the slot insulating paper 145 is slot insulating paper 145a made of a foamed adhesive sheet 141, varnish is not necessary, and the consumption of varnish used in the past can be further reduced.

According to the embodiments described above, it is possible to provide a stator, a rotating electric machine, and a method for manufacturing a stator that can stably fix the coil ends and ensure reliable vibration resistance.

[Other embodiments]
Although the embodiments of the present invention have been described above, the embodiments are presented as examples and are not intended to limit the scope of the invention. In addition, the features of each embodiment may be combined. Furthermore, the embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the gist of the invention. The embodiments and their modifications are included in the scope of the invention and its equivalents as described in the claims, as well as in the scope and gist of the invention.

1...rotating electric machine, 10...rotor, 11...rotor shaft, 12...rotor core, 13...permanent magnet, 14...closure plate, 21...bearing, 22...bearing bracket, 23...frame, 100...stator, 110...stator core, 110a...first end, 110b...second end, 111...stator slot, 112...stator teeth, 120...stator winding, 120a...coil end, 121...rectangular conductor, 125...crossover portion, 130, 130a, 130b...coil segment, 13 1...straight portion, 131a...first layer conductor, 131b...second layer conductor, 131c...third layer conductor, 131d...fourth layer conductor, 131e...fifth layer conductor, 131f...sixth layer conductor, 132...connection portion, 141...foamed adhesive sheet, 141a...base material, 141b...foamed adhesive portion, 142...adhesive insulating portion, 142a...first adhesive insulating portion, 142b...second adhesive insulating portion, 145...slot insulating paper, 200...coil end holding jig, 201...inner cylinder, 202...outer cylinder, 203...bottom, 205...storage space

Claims (2)

A cylindrical stator core having a plurality of stator slots formed in a circumferential direction on an inner peripheral surface thereof;
a stator winding including, for each phase, a plurality of coil segments, each of which has a straight portion with a rectangular cross section, a portion of which is accommodated in each of the two mutually different stator slots, and a connecting portion with a rectangular cross section connecting the two straight portions at an outer side of a first axial end of the stator core, and a plurality of jumper portions connecting the plurality of coil segments in series at an outer side of a second axial end of the stator core; and an adhesive insulating portion interposed between at least a portion of radially adjacent portions that are radially adjacent to each other at a coil end portion that is an outer portion of the first end of the stator winding;
A stator comprising:
The adhesive insulation portion is formed by disposing and adhering a foam adhesive sheet,
The foamed adhesive sheet has a planar substrate and a foamed adhesive layer applied to each of both sides of the substrate,
The straight portions are arranged such that portions of the straight portions that are accommodated in the stator slots form a plurality of layers in a radial direction,
The radially adjacent portions are bonded to each other by the adhesive insulating portion,
The adhesive insulating portion is disposed at every other radial position between the portions of the straight portions in the coil end portion corresponding to each of the plurality of layers.
A stator characterized by: In the plurality of stator slots, the slot insulating paper used is a simple insulating paper or the slot insulating paper of the foamed adhesive sheet, and in the case of the simple insulating paper, varnish is disposed between the insulating paper and the stator winding, and in the case of the slot insulating paper of the foamed adhesive sheet, no varnish is disposed between the slot insulating paper and the stator winding.
2. The stator according to claim 1 .

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