JP7521155B2 - Method for assembling insulating material for core and conductor of rotating electrical machine - Google Patents

Description

The present invention relates to a method for assembling a core and insulating material for a conductor of a rotating electric machine. More specifically, the present invention relates to a method for assembling a core of a rotating electric machine, such as a stator or rotor, and insulating material for a conductor inserted into a slot of the core, in an injection molding die.

Rotating electric machines having segment coils have been proposed as stators for rotating electric machines such as motors and generators. The conductors of the segment coils are rectangular, such as square or rectangular wire, in order to improve the efficiency of the motor (improving the space factor) (Patent Document 1, Patent Document 2). Furthermore, in order to improve assembly efficiency, it has also been proposed to use this segment coil as a throttle coil. The insulation material of the conductors of the throttle coil is replaced with insulating paper, and the resin is injection molded, and a rectangular wire coil is inserted into the slot of the stator and assembled to form a segment coil (Patent Document 3). A flange (brim part) is formed on one end of the insulation material, and this flange seals the gap between the insulation material and the slot, sealing the flow of varnish for fixing the winding. Patent Document 2 also proposes arranging a large number of teeth in the circumferential direction of a circular back yoke, inserting the teeth into an injection molding die, and injection molding a synthetic resin bobbin.

To prevent electrical losses in electric motors due to segment coils, it is necessary to increase the space factor of the conductors and to increase the electrical insulation between the conductors of the throttle coil. Increasing the thickness of the coils can increase the insulation, but this reduces the density of the conductors, lowering the space factor and increasing the size of the motor. On the other hand, heat generation due to copper loss in the stator of an electric motor is unavoidable, so heat resistance is also required. In other words, the insulating material that constitutes the segment coils is required to have both electrical insulation and heat resistance, and since the gap between the conductors is narrow, a thin material is required, so it must be formed as thin as possible. However, it is generally difficult to mold thin insulating materials that are required to have both insulation and heat resistance by injection molding because the flow of resin in the mold is poor. On the other hand, electric motors that require mass production and are used in electric vehicles, etc., require highly productive production technology due to demands such as cost reduction. In particular, under the above-mentioned constraints, there is also a demand for simplification of the production process for assembling the stator, etc.

JP 2008-35687 A JP 2019-161964 A JP 2018-125924 A

The present invention was made against the above technical background, and achieves the following objects.
SUMMARY OF THE PRESENT INVETION It is an object of the present invention to provide a method for assembling a core of a rotating electrical machine and an insulating material for a conductor by integrating the core of the rotating electrical machine and an insulating material for a conductor by injection molding in order to improve productivity.
Another object of the present invention is to provide a method for assembling a core and an insulator for a rotating electric machine, which comprises molding an insulator for a conductor made of a thermoplastic synthetic resin having high insulating properties and heat resistance into the slot of the core.
It is still another object of the present invention to provide a method for assembling a core and an insulating material for a rotating electrical machine, which has high productivity suitable for mass production.

In order to solve the above problems, the present invention takes the following measures.
That is, the method of assembling a core and an insulating material for a rotating electric machine according to the first aspect of the present invention includes an insulating material to be inserted into a slot provided in a stator or rotor of a rotating electric machine, the insulating material having a rectangular cross-sectional shape for inserting conductors, a plurality of through holes formed therein, the through holes being parallel to each other, the insulating material being made of a thermoplastic synthetic resin, and comprising a partition wall and an outer peripheral wall for electrically insulating the conductors from each other;
a slot coil having a cross-sectional shape similar to that of the through hole and configured with a conductor wire inserted into the through hole,
The insulating material is
a core insert step of inserting a core constituting the stator or the rotor into an injection molding die;
an insulating material partitioning step of inserting a core for the through hole into the slot in the axial direction of the stator or the rotor, and partitioning a cavity for molding a flange formed on the outermost periphery of one end of the through hole and having a cross-sectional area larger than that of the partition wall and the outer circumferential wall; and a resin injection step of injecting the molten thermoplastic synthetic resin into the cavity ,
The nozzle further comprises a gate communicating with the flange and provided on a side of the flange for injecting the molten thermoplastic synthetic resin in the axial direction.

The method for assembling a core and an insulating material for a rotating electric machine according to a second aspect of the present invention is characterized in that, in the first aspect of the present invention, the core is a divided core obtained by dividing the annular stator or rotor at an equal angle.
The method for assembling a core and an insulating material for a rotating electric machine of the present invention 3 is characterized in that, in the method for assembling the core and the insulating material for a rotating electric machine of the present invention 1 , the thermoplastic synthetic resin is a liquid crystalline wholly aromatic polyester having heat resistance and electrical insulation properties, the thickness of the partition wall and the outer peripheral wall is 0.15 to 0.55 mm, and the molding machine performing the resin injection process is a high-speed injection molding machine whose injection speed reaches a peak within 0.1 seconds.

The method of assembling a core and insulating material of a rotating electric machine of the fourth aspect of the present invention is characterized in that, in the third aspect of the present invention, the gate is a pinpoint gate, and the pinpoint gate is arranged in two locations in one slot of the insulating material, spaced apart in the circumferential direction of the core.

According to the method of assembling the core and insulating material of a rotating electric machine of the present invention, the insulating material for inserting the conductors can be integrally molded into the multiple slots of the core by injection molding, thereby shortening the assembly time of the core and insulating material.

FIG. 1 is a perspective view showing a core assembled by a method for assembling a core and an insulating material for a rotating electrical machine according to an embodiment of the present invention. FIG. 2 is a perspective view showing the core before assembly. FIG. 3 shows a state in which the core of FIG. 2 is inserted into a fixed die, and corresponds to a cross-sectional view taken along line AA of FIG. FIG. 4 shows a process subsequent to that shown in FIG. 3, in which the core and the movable die are pressed against the fixed die during injection molding, and corresponds to the AA cross section of FIG. FIG. 5 is an enlarged cross-sectional view of a portion P in FIG. FIG. 6 shows the state during injection molding when the core and the movable die are pressed against the fixed die, and corresponds to the cross-sectional view taken along line B--B in FIG. FIG. 7 is a perspective view showing an insulating material for a slot coil according to an embodiment of the present invention. FIG. 8 is a cross-sectional view taken along the line CC of FIG. FIG. 9 is a graph showing the injection speed waveform of an injection molding machine that molds an insulating material for a slot coil according to an embodiment of the present invention.

The following describes an embodiment of the present invention with reference to the drawings. Figure 1 is a perspective view showing a core assembled by the method for assembling a rotating electric machine core and insulating material according to an embodiment of the present invention, and Figure 2 is a perspective view showing the core before assembly. Figure 3 shows the state in which the core of Figure 2 is inserted into the fixed mold, and corresponds to the A-A cross section of Figure 1. Figure 4 shows the latter process of Figure 3, showing the state during injection molding when the core and the movable mold are pressed against the fixed mold, and corresponds to the A-A cross section of Figure 1. Figure 5 is an enlarged cross section of part P of Figure 4, and Figure 6 shows the state during injection molding when the core and the movable mold are pressed against the fixed mold, and corresponds to the B-B cross section of Figure 1. Figure 1 shows a split core 100 assembled by the assembly method according to an embodiment of the present invention, and shows the state in which eight insulating materials 1 shown in Figures 1 and 7 are integrally molded by injection molding into the eight slots 98 of the split core 99 before assembly shown in Figure 2.

The split cores 99 and 100 are formed by dividing an annular stator at 60 degree intervals, with a dovetail groove 97 formed on the right side and a dovetail protrusion 96 formed on the left side. The dovetail groove 97 in FIG. 1 is connected to the dovetail protrusion 96 of the adjacent split core, and the dovetail protrusion 96 in FIG. 1 is connected to the dovetail groove 97 of the adjacent split core to form an annular core. The inner peripheral surface of the split cores 99 and 100 is formed with radial gaps 95 that communicate with each of the eight slots 98. Figures 7 and 8 show the slot coil insulating material 1 that is injection molded into eight slots 98 by the assembly method of the embodiment of the present invention. The insulating material 1 of the embodiment of the present invention has six through holes 12 for inserting a conductor 11 with a rectangular cross section. The through holes 12 are formed in a rectangular shape similar in cross section to the conductor 11 and are formed parallel to each other. The conductor wire (copper wire, etc.) 11 is either uninsulated or resin-coated (approximately 60 μm). The insulating material 1 is made of thermoplastic synthetic resin and is formed by injection molding.

As shown in FIG. 8, the insulating material 1 has the same thickness (a, b, c) of the outer peripheral walls 131, 132 and the partition wall 133 of the through hole 12, and is formed thin, from 0.15 mm to 0.55 mm. The insulating material 1 has a flange 14 formed on the outer periphery of the upper end of the through hole 12. The flange 14 is composed of two long side flanges 15, 15 and one short side flange 16. The long side flanges 15, 15 are formed over the entire length of the two long sides, and the short side flange 16 is formed at one end of the long side flanges 15, 15 over the entire length of the short side. The thickness d of the long side flanges 15, 15 and the short side flange 16, and the height f of the long side flanges 15, 15 and the short side flange 16 are formed larger (for example, 1 mm) than the thicknesses a, b, c of the outer peripheral walls 131, 132 and the partition wall 133. At the midpoint of the long side flanges 15, 15 in the longitudinal direction, semicircular ear-shaped flanges 17, 17 are formed on the sides of the long side flanges 15, 15, protruding outward from the long side flanges 15, 15.

The method of assembling the core and insulating material of the rotating electric machine according to the embodiment of the present invention is as follows. First, as shown in FIG. 3, the split core 99 shown in FIG. 2 is mounted in the space surrounded by the fixed mold 2 and the fixed mold 3 of the injection molding machine (not shown). Next, as shown in FIG. 4 to FIG. 6, the core 4 for the through hole 12 of the insulating material 1 is inserted in the axial direction of the split core 99 into the slot 98 of the split core 99. The movable mold 5 is pressed against the upper surface of the fixed mold 3 to sandwich the split core 99 between the fixed mold 2 and the movable mold 5. The core 4 has six prismatic through hole core rods 41 in a row, each of which has the same rectangular cross-sectional shape as the through hole 12, and is parallel to each other and formed in eight fan-shaped rows. Also, as shown in FIG. 4, the core 4 has one radial gap core rod 42 formed at the right end of the through hole core rod 41. In this embodiment of the invention, the through-hole core rod 41 is rectangular with a cross section of 3 mm x 4 mm and a length of 100 mm.

As shown in FIG. 5, the through-hole core rod 41 has a tapered surface 411 and a straight surface 412. Similarly, the tip of the radial gap core rod 42 also has a tapered surface 421 and a straight surface 422. The bottom surface of the fixed die 2 has tapered holes 21, 22 and straight holes 23, 24. When the core 4 is inserted into the split core 99, the tapered surface 411 of the through-hole core rod 41 is guided into the tapered hole 21 and smoothly inserted, and the straight surface 412 fits into the straight hole 23, so that the through-hole core rod 41 is accurately positioned. Similarly, the tapered surface 421 of the radial gap core rod 42 is guided into the tapered hole 22 and smoothly inserted, and the straight surface 422 fits into the straight hole 24, so that the radial gap core rod 42 is accurately positioned.

As shown in FIG. 4, the gaps formed by the slots 98 of the split core 99, the through-hole core rod 41, and the radial gap core rod 42 form cavities for molding the outer peripheral walls 131, 132, and the partition wall 133. Also, the gaps formed by the lower surface of the movable die 5, the upper surface of the split core 99, and the left-end through-hole core rod 41 form cavities for molding the short side flanges 16. Also, as shown in FIG. 6, the gaps formed by the slots 98 of the split core 99 and the through-hole core rod 41 form cavities for molding the outer peripheral walls 131, 131. Also, as shown in FIG. 6, the gaps formed by the upper surface of the split core 99, the core 4, and the through-hole core rod 41 form cavities for molding the long side flanges 15, 15, and the ear-shaped flanges 17, 17.

As shown in FIG. 6, the thermoplastic synthetic resin injected from the nozzle of the injection molding machine (not shown) flows from the runner 61 through the gates 62, 62 into the ear-shaped flanges 17, 17. The gates 62, 62 are arranged at two locations spaced apart in the circumferential direction of the split core 99. The gates 62, 62 are pinpoint gates that connect to the ear-shaped flanges 17, 17 at small points. The direction in which the thermoplastic synthetic resin flows from the gates 62, 62 into the ear-shaped flanges 17, 17 is the height direction of the ear-shaped flanges 17, 17. As shown in FIG. 6, the thermoplastic synthetic resin that flows into the ear-shaped flanges 17, 17 from the gates 62, 62 hits the upper surface of the split core 99, changes direction by 90 degrees, reduces the inflow speed, and flows toward the thickness direction of the long side flanges 15, 15.

Then, the ear-like flanges 17, 17, the long side flanges 15, 15, and the short side flanges 16 are filled with thermoplastic synthetic resin. The thermoplastic synthetic resin then flows into the thin outer peripheral walls 131, 132 and the partition wall 133 at an optimal inflow speed, improving the flow of the thermoplastic synthetic resin and making it possible to produce a molded product with an accurate shape and a smooth shape. In other words, the ear-like flanges 17, 17, the long side flanges 15, 15, and the short side flanges 16 function as runners, allowing the thermoplastic synthetic resin to flow smoothly into the thin outer peripheral walls 131, 132 and the partition wall 133.

The thermoplastic synthetic resin used as the material for the insulating material 1 of the embodiment of the present invention is preferably liquid crystalline wholly aromatic polyester. Liquid crystalline wholly aromatic polyester has electrical insulation properties and heat resistance, and if the temperature is controlled accurately (molding temperature 320°C to 400°C), it has high fluidity and good moldability. However, liquid crystalline wholly aromatic polyester has a low melt viscosity during molding and a fast solidification speed, so in the case of ultra-thin products of 0.2 mm or less, the resin may solidify in the thin parts and sufficient fluidity may not be obtained. Therefore, since it cannot be molded with a general-purpose molding machine, it is preferable to use a high-speed injection molding machine whose injection speed reaches its peak within 0.1 seconds, as shown in Figure 9.

The above-mentioned embodiment is an example of a split core of a stator having slots, but it is not limited to this and may be a slotted core of a motor rotor or a split core thereof. Furthermore, it is not limited to a split core, and it may be a core itself that does not have a split structure that is inserted to form the insulating material 1. Although liquid crystalline wholly aromatic polyester is preferable as the thermoplastic synthetic resin, additives such as thermoplastic elastomers that increase fluidity, or fillers such as glass fibers and inorganic fillers may be added to this as necessary.

According to the method for assembling the core and insulating material of a rotating electric machine according to an embodiment of the present invention, the insulating material for inserting the conductor wires can be integrally molded into the multiple slots of the core by injection molding, thereby shortening the assembly time of the core and insulating material. In addition, there is no need to fill the gap between the inner surface of the slot and the outer surface of the insulating material with varnish, which makes it possible to reduce manufacturing costs. Furthermore, by using a split core, the number of core rods for through holes and radial gaps, which are difficult to machine with precision due to their long and thin shape, can be reduced, making it easier to manufacture the mold.

95...radial gap 96...dovetail protrusion 97...dovetail groove 98...slot 99, 100...split core 1...insulating material 11...conductor 12...through hole 131, 132...outer wall 133...partition wall 14...flange 15...long side flange 16...short side flange 17...ear-shaped flange 2...fixed mold 21, 22...tapered hole 23, 24...straight hole 3...fixed mold 4...core 41...core rod for through hole 411...tapered surface 412...straight surface 42...core rod for radial gap 421...tapered surface 422...straight surface 5...movable mold 61...runner 62...gate (pinpoint gate)

Claims (4)

an insulating material which is inserted into a slot provided in a stator or rotor of a rotating electric machine, has a rectangular cross-sectional shape for inserting conductors, has a plurality of through holes formed therein, is molded from a thermoplastic synthetic resin, the through holes are parallel to each other, and is made up of a partition wall and an outer peripheral wall for electrically insulating the conductors from each other;
a slot coil having a cross-sectional shape similar to that of the through hole and configured with a conductor wire inserted into the through hole,
The insulating material is
a core insert step of inserting a core constituting the stator or the rotor into an injection molding die;
an insulating material partitioning step of inserting a core for the through hole into the slot in the axial direction of the stator or the rotor, and partitioning a cavity for molding a flange formed on the outermost periphery of one end of the through hole and having a cross-sectional area larger than that of the partition wall and the outer circumferential wall; and a resin injection step of injecting the molten thermoplastic synthetic resin into the cavity ,
a gate communicating with the flange and provided on a side of the flange for injecting the molten thermoplastic synthetic resin in the axial direction. 2. The method for assembling a core and an insulating material for a rotating electric machine according to claim 1,
a core that is formed by dividing the stator or rotor having an annular shape at an equal angle; 2. The method for assembling a core and an insulating material for a rotating electric machine according to claim 1 ,
the thermoplastic synthetic resin is a liquid crystalline wholly aromatic polyester having heat resistance and electrical insulation properties,
The thickness of the partition wall and the outer peripheral wall is 0.15 to 0.55 mm,
a molding machine that performs the resin injection step is a high-speed injection molding machine whose injection speed reaches a peak within 0.1 seconds. 4. A method for assembling a core and an insulating material for a rotating electric machine according to claim 3 , comprising the steps of:
the gate is a pinpoint gate;
a pinpoint gate disposed in one slot of the insulating material at two locations spaced apart in a circumferential direction of the core;

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