JP7365949B2 - Insulating sheet, stator manufacturing method, and stator - Google Patents

Description

The present invention relates to an insulating sheet, a method for manufacturing a stator, and a stator.

In rotating electrical machines such as electric motors, insulating sheets are used to insulate a stator and windings. An adhesive material such as resin is placed on the surface of the insulating sheet to bring it into close contact with both the stator and the windings.

Cited Document 1 discloses an insulating sheet in which a thermosetting adhesive encapsulated in microcapsules is dispersed in a nonwoven fabric on both sides of an insulating paper. The curing temperature of this adhesive is set higher than the softening temperature of the microcapsule skin. When such an insulating sheet is used, the adhesive can be brought into close contact with the stator and the windings by raising the temperature of the insulating sheet after the windings are inserted.

Japanese Patent Application Publication No. 2015-50856

The method of manufacturing a stator using the above-mentioned conventional insulating sheet is to insert the windings into the slots and then apply heat to harden the adhesive. In this manufacturing method, the adhesive is not cured when the winding is inserted, and the insulating sheet is not fixed in the slot when the winding is inserted into the stator slot, so the winding gets caught in the insulating sheet. For example, the insulation sheet may shift.

To prevent this, it is conceivable to use a jig to hold down the insulating sheet or to create creases in advance so that the insulating sheet does not shift, but this increases the number of steps and is less effective.

The present invention has been made in view of these problems, and it is an object of the present invention to provide an insulating sheet that can prevent misalignment when windings are inserted into a stator, and also to prevent a decrease in insulation properties caused by misalignment of the insulating sheet. It is an object of the present invention to provide a stator and a stator manufacturing method that can reduce the amount of damage.

One embodiment of the present invention is applied to an insulating sheet that is interposed between a slot of a stator and a winding wound around the slot, and electrically insulates the inner wall of the slot and the winding. This insulating sheet includes an insulating paper, a first adhesive layer in which a thermosetting first adhesive is disposed on a first surface of the insulating paper on the inner wall side of the slot, and a second surface of the insulating paper on the winding side. and a second adhesive layer in which a thermosetting second adhesive is disposed. The curing temperature of the first adhesive layer is lower than the curing temperature of the second adhesive layer.

According to the present invention, by attaching the insulating sheet to the slot and raising the temperature to the first temperature, the inner wall of the slot and the insulating sheet are fixed by the first adhesive, and at this time, the adhesion of the second adhesive on the winding side is also maintained. does not change. Therefore, since the winding can be inserted with the insulating sheet fixed, it is possible to prevent the insulating sheet from shifting when inserting the winding.

FIG. 1 is an explanatory diagram of a stator according to an embodiment of the present invention. FIG. 2 is an enlarged view of the stator slots. FIG. 3 is an explanatory diagram of an insulating sheet. FIG. 4 is a flowchart of a stator assembly method. FIG. 5 is an explanatory diagram of an insulating sheet according to a modification of the embodiment of the present invention. FIG. 6 is an explanatory diagram of an insulating sheet according to another modification of the embodiment of the present invention. FIG. 7 is an explanatory diagram of an insulating sheet according to another modification of the embodiment of the present invention.

Embodiments of the present invention will be described below with reference to the drawings and the like.

FIG. 1 is an explanatory diagram of a stator 10 of a rotating electric machine (motor) to which an insulating sheet according to an embodiment of the present invention is applied, as viewed from the direction of the rotation axis.

The stator 10 includes a stator core 11 in which a plurality of slots 12 are formed, a winding 30 inserted into the slot 12, and an insulating sheet 20 that electrically insulates between the stator core 11 and the winding 30 (see FIG. 2). It is composed of:

The stator core 11 is constructed by stacking electromagnetic steel plates punched in an annular shape in the direction of the rotation axis. The stator core 11 is formed with an annular back yoke 13 and a plurality of teeth 14 protruding inward from the back yoke 13.

A gap formed between the teeth 14 constitutes a slot 12, and a winding 30 (shown by hatching in FIG. 1) is inserted into the slot 12.

A rotor (not shown) is arranged on the inner peripheral side of the stator 10. By passing current through the windings 30 of the stator 10, the rotor rotates due to the action of the permanent magnets provided in the rotor.

Although the stator core 11 shown in FIG. 1 shows an example in which 48 slots 12 are formed, the number of slots 12 is not limited to this.

The rotating electric machine of this embodiment is mounted, for example, on an electric vehicle, and functions as an electric motor that drives wheels. Further, the rotating electric machine functions as a generator that generates power (regeneration) by receiving driving force from rotation of wheels. Note that the rotating electric machine may be used as a drive device for devices other than automobiles, such as various electrical devices or industrial machines.

Next, the configuration of the slots 12 of the stator 10 will be explained.

FIG. 2 is a partially enlarged view of the slots 12 of the stator 10 of this embodiment. Although FIG. 2 will be described as a representative example of one of the plurality of slots 12 in FIG. 1, the configurations of the other slots 12 are also the same.

Slot 12 is a gap formed between teeth 14 in stator 10 . A protrusion 14a that protrudes in the circumferential direction is formed at the tip of the teeth 14, and a slot 12 opens toward the inner circumferential side of the stator 10 due to a gap 15 between the protrusions 14a.

A winding 30 is inserted into the slot 12, and an insulating sheet 20 is interposed between the inner wall 12a of the slot 12 and the winding 30.

Insulating sheet 20 electrically insulates between stator core 11 and winding 30. Further, the insulating sheet 20 is provided with an adhesive on its surface as will be described later, and the inner wall 12a of the slot 12 and the winding 30 are tightly fixed by the adhesive.

The winding 30 is made of a rectangular wire with an insulating coating. In the example shown in FIG. 2, six rows of rectangular wires are housed in one slot 12 in the radial direction. The winding 30 is constituted by these plural rectangular wires. Note that the number and shape of the windings 30 are not limited to these.

FIG. 3 is an explanatory diagram of the insulating sheet 20 of this embodiment.

The insulating sheet 20 includes an insulating paper 21, a first adhesive layer 22 containing a first adhesive on a first surface of the insulating paper 21 on the inner wall 12a side of the slot 12, and a first adhesive layer 22 containing a first adhesive on the first surface of the insulating paper 21 on the inner wall 12a side of the slot 12, and a first adhesive layer 22 on the first surface of the insulating paper 21 on the inner wall 12a side of the slot 12, and and a second adhesive layer 23 containing a second adhesive on its surface.

The insulating paper 21 is formed into a sheet shape from an insulating material such as paper, nonwoven fabric, or resin.

A thermosetting first adhesive is applied to the first adhesive layer 22 to a predetermined thickness (predetermined amount). A thermosetting second adhesive is applied to the second adhesive layer 23 to a predetermined thickness (predetermined amount).

The first adhesive material and the second adhesive material are cured at a predetermined curing temperature. Further, the first adhesive material and the second adhesive material each have a glass transition temperature lower than the curing temperature. And preferably, the glass transition temperature of the second adhesive is set higher than the curing temperature of the first adhesive.

The glass transition temperature is the temperature at which a substance transitions from a solid state to a melted and highly fluid state. By melting the adhesive, the adhesive flows into the gap between the insulating sheet 20 and the inner wall 12a and the gap between the insulating sheet 20 and the winding 30, so that they are brought into close contact with each other. The curing temperature is a temperature higher than the glass transition temperature at which the molten adhesive material is cured.

Here, an insulating sheet in a conventional stator will be considered.

Prior to inserting the windings into the slots of the stator, an insulating sheet is attached to the slots. If the winding is inserted into the slot in this state, the insulation sheet is not fixed in the slot, so the winding may get caught on the insulation sheet and the insulation sheet may shift, causing the insulation between the stator and the winding to There may be a decrease in sexual performance.

To prevent this, it is conceivable to use a jig to hold down the insulating sheet or to create creases in advance so that the insulating sheet does not shift, but this increases the number of steps and is less effective.

Therefore, in the embodiment of the present invention, the curing temperature of the first adhesive material and the curing temperature of the second adhesive material of the insulating sheet 20 are made different. That is, in the insulating sheet 20, the curing temperature of the first adhesive of the first adhesive layer 22 is set to be lower than the curing temperature of the second adhesive of the second adhesive layer 23.

With this configuration, before inserting the winding 30 into the slot 12, only the first adhesive can be cured to fix the insulating sheet 20 to the inner wall 12a. It is possible to prevent the insulating sheet 20 from shifting during insertion.

FIG. 4 is a flowchart showing a method for assembling the stator 10 using the insulating sheet 20 of this embodiment.

First, in step S10, insulating sheets 20 are installed in all the slots 12 of the stator 10, respectively.

At this time, it is desirable to bring the first adhesive layer 22 on the first surface of the insulating sheet 20 into close contact with the inner wall 12a of the slot 12 using a jig or the like.

Next, in step S20, the insulating sheet 20 installed in the slot 12 is heated to a first temperature.

For example, the entire stator 10 may be placed in a furnace, and the insulating sheets 20 attached to each slot 12 may be heated to the first temperature. Moreover, the jig for bringing the insulating sheets 20 into close contact may have a heating mechanism, and each insulating sheet 20 may be heated to the first temperature by the heating mechanism.

Note that the first temperature is higher than the glass transition temperature and curing temperature of the first adhesive of the first adhesive layer 22 and is a temperature at which the first adhesive is sufficiently cured, and is higher than the curing temperature of the first adhesive of the first adhesive layer 22 . The temperature is lower than the glass transition temperature of the second adhesive.

After raising the first temperature, the insulating sheet 20 is maintained at the first temperature for a predetermined period of time until the first adhesive is sufficiently cured.

Through this step S20, the first adhesive is melted and spreads over the gap between the first adhesive layer 22 and the inner wall 12a. Thereafter, the first adhesive is cured, thereby fixing the insulating sheet 20 and the inner wall 12a of the slot 12. Note that the jig is removed after the insulating sheet 20 is fixed to the inner wall 12a of the slot 12.

Next, in step S30, the winding 30 is inserted into each slot 12.

The winding 30 is composed of a plurality of rectangular wires having a U-shape. This rectangular wire is inserted in the axial direction of the slot 12 from the open end. Thereafter, the winding 30 is formed by electrically connecting the open ends of the flat wires.

At this time, since the inner wall 12a of the slot 12 and the insulating sheet 20 are fixed with the first adhesive, the insulating sheet 20 will not shift. Further, at this point, the second adhesive of the second adhesive layer 23 of the insulating sheet 20 has not been heated to the glass transition temperature, so it does not have fluidity and does not prevent the winding 30 from being inserted.

Next, in step S40, the insulating sheet 20 installed in the slot 12 is heated to a second temperature.

At this time, as in step S20, the entire stator 10 is placed in the furnace, and the insulating sheet 20 is heated to the second temperature.

Note that the second temperature is higher than the glass transition temperature and curing temperature of the second adhesive of the second adhesive layer 23, and is a temperature at which the second adhesive is sufficiently cured.

After raising the second temperature, the insulating sheet 20 is maintained at the second temperature for a predetermined period of time until the second adhesive is sufficiently cured.

Through this step S40, the second adhesive is melted and spreads over the gap between the second adhesive layer 23 and the winding 30. Thereafter, the second adhesive is cured, thereby fixing the insulating sheet 20 and the winding 30.

Through the process described above, the insulating sheet 20 is fixed to the inner wall 12a of the slot 12 by the first adhesive before the winding 30 is inserted into the slot 12. can be prevented from shifting.

Next, a modification of this embodiment will be described.

As described above, in this embodiment, after the first adhesive is cured at the first temperature, the second adhesive is cured at the higher second temperature.

Here, depending on the material and characteristics of the first adhesive, the adhesive strength of the first adhesive may decrease due to the temperature rising to the second temperature higher than the first temperature, and the adhesive force between the insulating sheet 20 and the inner wall may decrease. 12a may be weakened.

On the other hand, it is possible to select the material of the first adhesive so that the adhesive strength does not decrease even at the second temperature, but in this case, the material cost of the first adhesive may increase. be.

Therefore, as a method that does not increase the cost of the first adhesive and do not reduce the adhesive force even at the second temperature, a second adhesive that hardens at the second temperature is added to a part of the first adhesive layer 22 of the insulating sheet 20. Distribute the materials. Thereby, when the temperature rises to the second temperature, the second adhesive material is cured, and the fixation of the insulating sheet 20 and the inner wall 12a is maintained.

5 to 7 show examples in which the second adhesive is dispersed and arranged in the first adhesive layer 22.

FIG. 5 shows an example in which, in the first adhesive layer 22, first adhesive materials and second adhesive materials (indicated by hatching) are alternately arranged in a band shape in the axial direction of the stator 10 of the insulating sheet 20.

FIG. 6 shows an example in which the first adhesive material and the second adhesive material are alternately arranged in the first adhesive layer 22 in a band shape in a direction perpendicular to the axial direction of the stator 10 of the insulating sheet 20.

FIG. 7 shows an example in which, in the first adhesive layer 22, the second adhesive is dispersed and arranged in a circular shape within the first adhesive of the insulating sheet 20.

With such a configuration, the second adhesive disposed on the first adhesive layer 22 is cured by increasing the temperature to the second temperature, thereby fixing the insulating sheet 20 and the inner wall 12a. This can prevent the first adhesive layer 22 from weakening the fixation between the insulating sheet 20 and the inner wall 12a without increasing the cost of the first adhesive.

Next, the effects of this embodiment configured as described above will be explained.

This embodiment is applied to an insulating sheet 20 that is interposed between the stator 10 and the winding 30 inserted into the slot 12 of the stator 10, and electrically insulates the inner wall 12a and the winding 30. This insulating sheet 20 includes an insulating paper 21, a first adhesive layer 22 made of a thermosetting first adhesive disposed on a first surface of the insulating paper 21 on the inner wall 12a side of the slot 12, and an insulating paper 21. a second adhesive layer 23 made of a thermosetting second adhesive disposed on the second surface on the winding 30 side, and the curing temperature of the first adhesive is lower than the curing temperature of the second adhesive. is also set low.

In this embodiment, the curing temperature of the first adhesive is set lower than the curing temperature of the second adhesive. To provide an insulating sheet 20 that can tightly fix the insulating sheet 20 to the inner wall 12a and prevent the insulating sheet 20 from shifting when the winding 30 is inserted, and to provide a stator 10 configured in this way. be able to.

Further, in this embodiment, the curing temperature of the first adhesive is set lower than the glass transition temperature of the second adhesive. As a result, the second adhesive does not melt at the temperature at which the first adhesive hardens and does not have fluidity, so that it does not get caught on the second surface of the insulating sheet 20 when the winding 30 is inserted, and the insulating sheet 2 This can prevent misalignment.

Furthermore, in this embodiment, the second adhesive is disposed on at least a portion of the first adhesive layer 22 on the first surface. As a result, after the winding 30 is inserted into the slot 12, the second adhesive material disposed on the first adhesive layer 22 is cured by increasing the temperature to the second temperature, and the insulating sheet 20 and the inner wall 12a are bonded together. Since they are fixed, it is possible to prevent the fixation between the insulating sheet 20 and the inner wall 12a from weakening due to a decrease in the adhesive force of the first adhesive, without increasing the cost of the first adhesive.

Further, in this embodiment, the curing temperature of the first adhesive is set lower than the curing temperature of the second adhesive, and the procedure for attaching the insulating sheet 20 to the inner wall 12a of the slot 12 of the stator 10 and , a step of raising the temperature to a first temperature higher than the curing temperature of the first adhesive, a step of inserting the winding 30 into the slot 12 after the temperature rise, and a step of inserting the insulating sheet 20 into the second and raising the temperature to a second temperature higher than the curing temperature of the adhesive.

As a result, prior to inserting the winding 30 into the slot 12, the first adhesive is heated to the first temperature so that the insulating sheet 20 can be closely fixed to the inner wall 12a. 2. The adhesive does not melt and can prevent the insulation sheet 20 from shifting when the winding 30 is inserted. Furthermore, by raising the temperature to the second temperature, the winding 30 and the insulating sheet 20 can be tightly fixed.

The embodiments of the present invention and modifications thereof have been described above, but the above embodiments and modifications merely show a part of the application examples of the present invention, and the technical scope of the present invention is not limited to the above embodiments. It is not intended to be limited to specific configurations.

In this embodiment, an example is shown in which the rectangular wire winding 30 is inserted into the slot 12, but the present invention is not limited to this, and the winding may be made of a round wire, for example.

10 Stator 11 Stator core 12 Slot 12a Inner wall 20 Insulating sheet 21 Insulating paper 22 First adhesive layer 23 Second adhesive layer 30 Winding

Claims (5)

An insulating sheet that is interposed between a winding inserted into a slot of a stator and the stator and electrically insulates an inner wall of the slot and the winding,
insulating paper and
a first adhesive layer in which a thermosetting first adhesive is disposed on a first surface of the insulating paper on the inner wall side of the slot;
a second adhesive layer in which a thermosetting second adhesive is disposed on a second surface of the insulating paper on the winding side;
Equipped with
The curing temperature of the first adhesive is set lower than the curing temperature of the second adhesive. Insulating sheet. The insulating sheet according to claim 1,
The curing temperature of the first adhesive is set lower than the glass transition temperature of the second adhesive. The insulating sheet according to claim 1 or 2,
The second adhesive is disposed on at least a portion of the first adhesive layer on the first surface. The insulating sheet. A method for manufacturing a stator for a rotating electric machine, the method comprising:
A step of attaching the insulating sheet according to any one of claims 1 to 3 to the inner wall of the slot of the stator;
raising the insulating sheet to a first temperature higher than the curing temperature of the first adhesive;
inserting the winding into the slot after the temperature rises;
After inserting the winding, raising the insulating sheet to a second temperature higher than the curing temperature of the second adhesive layer;
A method for manufacturing a stator having: A stator for a rotating electrical machine,
Any one of claims 1 to 3, comprising a stator core, a winding inserted into a slot formed in the stator core, and a winding arranged in the slot to electrically insulate an inner wall of the slot and the winding. Equipped with the insulating sheet described in
the insulating sheet and the inner wall of the slot are fixed with a first adhesive;
The insulating sheet and the winding are fixed to each other with a second adhesive.

Images