JP2023132503A - Rotator of dynamo-electric motor - Google Patents

Abstract

To provide a rotator 1 of a dynamo-electric motor, comprising: a rotational axis 2; a cylindrical core 6 that is extended to a shaft direction, and is externally fitted to the rotational axis 2; a pair of core pressing 7 and 7 that fixes the core 6 with a pressure in narrow to the rotational axis 2; a plurality of permanent magnets 3 or a secondary conductor which is provided while having an interval to a peripheral direction, and is embedded into the core 6; and a reinforcement pipe 4 that is formed by a heat hardening of a prepreg sheet in which a thermosetting resin is impregnated into a fiber base, capable of suppressing the scattering of all of the permanent magnets 3 or all of the secondary conductors from the rotational shaft 2 even at a high-speed rotation, as a low-cost general-purpose product.SOLUTION: Concaves 7a and 6a are provided at a plurality of places in a peripheral direction on an outer peripheral surface of each core presser 7 or a core 6. A prepreg sheet is wound around an outer periphery of the core 6 and each core presser 7. A plurality of places in the peripheral direction of a reinforcement pipe 4 is entered into the concaves 7a and 6a by a heat hardening. The reinforcement pipe 4 is adhered to the outer peripheral surface of the core 6 and each core presser 7.SELECTED DRAWING: Figure 2

Description

The present invention relates to a rotor for an electric motor, which includes a rotating shaft and a plurality of permanent magnets or secondary conductors arranged in the axial direction and provided at circumferential intervals on the outer periphery of the rotating shaft.

Conventionally, as a rotor for this type of electric motor, an axially extending reinforcing tube formed by heating and curing a prepreg sheet in which a fiber base material is impregnated with a thermosetting resin is in close contact with the outer peripheral surface of all permanent magnets. Some are known (for example, see Patent Document 1).

Regarding the rotor of such an electric motor, it is required to suppress all the permanent magnets from scattering outward from the rotating shaft even due to centrifugal force during high-speed rotation. In order to meet this requirement, it is necessary to increase the adhesion strength of the reinforcing tube. Therefore, in the electric motor rotor described in Patent Document 1, a cylindrical reinforcing tube into which a rotating shaft with a permanent magnet attached can be inserted is prepared in advance, and a hollow one is used for the rotating shaft. There is. Then, the rotor of the electric motor is manufactured using a method called cold fitting. That is, a refrigerant such as liquid nitrogen is caused to flow through the hollow portion of the rotating shaft to contract the rotating shaft inward in the radial direction. Thereafter, the rotating shaft is inserted into the reinforcing tube to stop the flow of refrigerant and the temperature of the rotating shaft is returned to room temperature, thereby expanding the rotating shaft radially outward and returning to its original size. Then, the reinforcing tube is brought into close contact with the outer peripheral surfaces of all the permanent magnets.

JP 2017-50925 Publication

However, the rotor of the electric motor described in Patent Document 1 uses a special method of cold fitting for manufacturing, and not only requires a special jig, but also a cylindrical reinforcing tube. A jig and a hollow rotating shaft are also required to make the prepreg from a single piece of prepreg. Therefore, there is considerable room for reexamination in order to make the rotor of the electric motor described in Patent Document 1 an inexpensive general-purpose product.

In view of the above points, the present invention provides a rotor for an electric motor that can be an inexpensive general-purpose product while suppressing all permanent magnets or all secondary conductors from scattering outward from the rotating shaft even during high-speed rotation. The task is to provide.

In order to solve the above problems, the present invention first provides a rotating shaft, a plurality of permanent magnets arranged in the axial direction, and attached to the outer circumferential surface of the rotating shaft at intervals in the circumferential direction. A rotor for an electric motor equipped with an axially extending reinforcing tube, which is formed by heating and curing a prepreg sheet in which a fiber base material is impregnated with a thermosetting resin, is in close contact with the outer peripheral surface of all permanent magnets. A pair of magnet holders are provided at both ends of each permanent magnet in the axial direction, and are fitted onto the rotating shaft to tightly fix all the permanent magnets. Recesses are formed at multiple locations, the prepreg sheet is wrapped around the outer periphery of all permanent magnets together with a pair of magnet holders, and multiple locations in the circumferential direction of the reinforcing tube enter each recess, so that the reinforcing tube It is characterized by being adhered to the outer peripheral surface of a permanent magnet.

According to the first feature of the present invention, a part of the thermosetting resin impregnated during heat curing of the prepreg sheet infiltrates into the recesses provided in each magnet holder and hardens. Multiple locations in the circumferential direction of the reinforcing tube function as anchors. Therefore, the adhesive strength between all the permanent magnets and the pair of magnet holders and the reinforcing tube is sufficiently high, comparable to the adhesive strength obtained by cold fitting as described above. Therefore, even during high-speed rotation, all the permanent magnets can be prevented from scattering outward from the rotating shaft. Then, using a pair of magnetic holders that are fitted around the rotating shaft and have recesses in multiple locations in the circumferential direction of the outer circumferential surface, a prepreg sheet that will later become a reinforcing tube is held together with a pair of magnetic holders, all of the permanent magnets. The motor rotor is manufactured by wrapping the material around the outer periphery of the material and heating and hardening it, so the motor rotor can be an inexpensive general-purpose product.

The rotor of the electric motor to which the first feature of the present invention is directed is of the so-called SPM (Surface Permanent Magnet) type, in which all permanent magnets are attached to the rotating shaft. The recesses and prepreg sheets in the so-called IPM (Internal Permanent Magnet ) type electric motor rotor.

Therefore, secondly, the present invention provides a rotating shaft, a cylindrical core extending in the axial direction and fitting around the rotating shaft, and a core located at both ends of the core in the axial direction and fitting around the rotating shaft. A pair of core holders for tightly fixing the core holder, and a plurality of permanent magnets or secondary conductors arranged in the axial direction and spaced apart in the circumferential direction between the pair of core holders. A rotor of an electric motor, in which a permanent magnet or a secondary conductor is embedded in a core, and a reinforcing tube extending in the axial direction is formed by heating and curing a prepreg sheet in which a fiber base material is impregnated with a thermosetting resin. In the case where the core is in close contact with the outer circumferential surface of the core and the pair of core holders, depressions are provided at multiple locations in the circumferential direction on the outer periphery of the pair of core holders or the core, and a prepreg sheet is provided on the outer periphery of the pair of core holders and the core. A reinforcing tube extending in the axial direction is formed by being wrapped and heated and hardened, and multiple points in the circumferential direction of this reinforcing tube enter the depressions, and the reinforcing tube is bonded to the outer circumferential surface of the core and the outer circumferential surfaces of the pair of core holders. It is characterized by

According to the second feature of the present invention, similarly to the first feature, a plurality of locations in the circumferential direction of the reinforcing tube that has entered the depression function as anchors to bond the reinforcing tube to the core and the pair of core holders. The strength is sufficiently high, and it is possible to prevent all permanent magnets or all secondary conductors from scattering outside the core even during high-speed rotation. The manufactured rotor of the electric motor can be an inexpensive general-purpose product.

Thirdly, the present invention provides a rotating shaft, a cylindrical core that extends in the axial direction and fits around the rotating shaft, and a core that is located at both ends of the core in the axial direction and fits around the rotating shaft. A pair of core holders for tightly fixing the core holder, and a plurality of permanent magnets or secondary conductors arranged in the axial direction and spaced apart in the circumferential direction between the pair of core holders. A rotor of an electric motor, in which a permanent magnet or a secondary conductor is embedded in a core, and a reinforcing tube extending in the axial direction is formed by heating and curing a prepreg sheet in which a fiber base material is impregnated with a thermosetting resin. A plurality of grooves extending in the axial direction are formed on the outer circumferential surface of the core and are located between the buried locations of each permanent magnet or each secondary conductor, in a device that is in close contact with the outer circumferential surface of the core and the pair of core holders, A thermosetting resin binder is inserted into each groove of the core, a prepreg sheet is wrapped around the core and each binder together with a pair of core holders, and a reinforcing tube extending in the axial direction is formed by heating and curing. The pipe is bonded to the outer circumferential surface of the core and the outer circumferential surfaces of the pair of core holders, and the reinforcing tube is also bonded to each groove of the core via each heat-cured binder.

According to the third feature of the present invention, the thermosetting resin binder inserted into each groove functions as an anchor instead of entering the reinforcing tube into the recesses at multiple locations in the circumferential direction. Therefore, similar to the second feature above, the adhesive strength between the core and the pair of core holders and the reinforcing tube becomes sufficiently high, and even during high-speed rotation, all the permanent magnets or all the secondary conductors scatter to the outside of the core. It is possible to prevent this from happening. The manufactured rotor of the electric motor can be an inexpensive general-purpose product.

(a) is an axial cross-sectional view schematically showing an embodiment of a rotor of an electric motor corresponding to the first feature of the present invention. (b) is an AA sectional view of the same embodiment. FIG. 3 is an axial sectional view schematically showing an embodiment of a rotor of an electric motor corresponding to a second feature of the present invention. (a) is an AA sectional view schematically showing a step of winding prepreg when manufacturing the embodiment shown in FIG. 2; (b) is a sectional view taken along line AA of the embodiment shown in FIG. 2. FIG. 3 is a radial cross-sectional view schematically showing a rotating shaft, a core, and a permanent magnet in an embodiment of a rotor of an electric motor according to a third feature of the present invention. (a), (b), and (c) are radial cross-sectional views schematically showing each step in manufacturing the embodiment shown in FIG. 4, respectively. An outline of the rotor precursor after the step shown in FIG. 5(b) and an outline of an embodiment of the rotor of the electric motor corresponding to the third feature of the present invention after the step shown in FIG. 5(c) FIG.

The embodiment shown in FIGS. 1(a) and 1(b) is an example of a rotor of an electric motor classified as the above-mentioned SPM. The electric motor is a motor, and the rotor 1 includes a rotating shaft 2 and a plurality of permanent magnets 3 arranged in the axial direction and attached to the outer peripheral surface of the rotating shaft 2 at intervals in the circumferential direction. ing. The rotating shaft 2 is made of a metal material containing iron or other magnetic material. Specifically, in each permanent magnet 3, a plurality of magnet pieces 3a, which are constituent units of each permanent magnet 3, are arranged in a line in the axial direction, and are attached to the outer peripheral surface of the rotating shaft 2 by the magnetic force of the magnet pieces 3a. It is being As long as each permanent magnet 3 generates a magnetic field that can satisfy the required performance of the motor, the number of permanent magnets 3, the mounting position on the rotating shaft 2, etc. are not particularly limited. Moreover, the material forming the magnet piece 3a is not particularly limited either.

In addition, in the rotor 1, a reinforcing tube 4 extending in the axial direction, which is formed by heating and curing a prepreg sheet in which a fiber base material is impregnated with a thermosetting resin, is in close contact with the outer peripheral surface of all the permanent magnets 3. There is. For the prepreg sheet, the fiber base material can be, for example, woven or nonwoven fabrics such as carbon fibers, silicon carbide fibers, tyranno (SiTiC) fibers, Kevlar fibers, alumina fibers, and boron fibers. Epoxy resin, polyimide resin, polyether ether ketone resin, etc. can be used as the thermosetting resin. The reinforcing tube 4 formed from the prepreg sheet is lightweight and strong enough to prevent all the permanent magnets 3 from scattering outward from the rotating shaft 2 even during high-speed rotation. desirable. The above-mentioned fiber base material and the above-mentioned thermosetting resin are selected in consideration of the above.

Further, the rotor 1 is provided with a pair of magnet holders 5, 5, which are located at both ends of each permanent magnet 3 in the axial direction and are fitted onto the rotating shaft 2 to fix all the permanent magnets 3 under narrow pressure. . Recesses 5a are provided at a plurality of locations in the circumferential direction on the outer peripheral surface of each magnet holder 5. The reinforcing tube 4 is inserted into each depression 5a at a plurality of places in the circumferential direction, so that the reinforcing tube 4 is located on the outer circumferential surface of all the permanent magnets 3 and on the outer periphery of the pair of magnet holders 5, 5 located on the permanent magnet 3 side. It is glued to the surface. All the permanent magnets 3 and the pair of magnet holders 5, 5 are bonded to the reinforcing tube 4 by wrapping the prepreg sheet together with the pair of magnet holders 5, 5 around the outer peripheral surfaces of all the permanent magnets 3, and then heating and hardening. When forming the reinforcing tube 4, a part of the thermosetting resin infiltrates into each recess 5a formed in each magnet holder 5 and hardens. The plurality of locations in the circumferential direction of the reinforcing tube 4 that have entered each depression 5a function as anchors, and the adhesive strength between all the permanent magnets 3 and the pair of magnet holders 5, 5 and the reinforcing tube 4 is lower than that of the conventional cooling method. The adhesion strength is high enough to be comparable to the adhesion strength due to fitting.

More specifically, the width dimension of the prepreg sheet in the axial direction is set to the length outside all the recesses 5a of each magnet holder 5 in the axial direction, and the prepreg sheet is pulled out from the original fabric and placed in the so-called B stage. Together with the pair of magnet holders 5, 5, the permanent magnets 3 are wound around the outer periphery of all the permanent magnets 3 with a predetermined tension. In addition, when bonding the reinforcing tube 4 to all the permanent magnets 3 and the pair of magnet holders 5, 5, the prepreg sheet was wrapped around the outer periphery of all the permanent magnets 3 together with the pair of magnet holders 5, 5. The precursor is stored in a bag, container, etc. that can be depressurized, and the prepreg sheet is deformed by the depressurization so as to follow the inner surface of each recess 5a of each magnet holder 5 and the outer peripheral surface of each permanent magnet 3. let Then, the precursor is heated to the curing temperature of the thermosetting resin of the prepreg sheet. Heating at this time may be a continuous process while the product is stored inside a bag, container, etc., or a batch process where the product is once taken out outside and then stored again inside a heat treatment path or the like and then heated.

For example, as described above, the rotor 1 of the motor of the present embodiment manufactured in this manner has sufficiently high adhesive strength between all the permanent magnets, the pair of magnet holders 5, 5, and the reinforcing tube 4, and the rotor It is possible to suppress all the permanent magnets 3 from scattering outward from the rotating shaft 2 even during high-speed rotation. The rotor 1 of the motor is constructed by using a pair of magnet retainers 5 which are fitted onto the rotating shaft 2 and have recesses 5a at a plurality of locations in the circumferential direction on the outer circumferential surface of the prepreg sheet, which will later become the reinforcing tube 4. The rotor 1 of the motor can be an inexpensive general-purpose product because it is manufactured by winding the permanent magnets 3 together with the pair of magnet holders 5, 5 around the outer periphery of all the permanent magnets 3 and heating and hardening them.

FIGS. 2 and 3(a) and 3(b) show an embodiment of a rotor of an electric motor classified as the above-mentioned IPM. Note that the same parts and parts as in the embodiment shown in FIGS. 1(a) and 1(b) are designated by the same reference numerals, and description thereof will be omitted.

The electric motor shown in FIGS. 2 and 3(a) and 3(b) is also a motor, but the permanent magnet 3 can be replaced with a secondary conductor such as a winding, and in this case, the electric motor becomes a generator. The rotor 1 of the motor shown in FIGS. 2 and 3(a) and 3(b) includes a cylindrical core 6 that is fitted onto the rotating shaft 2, and a core 3 that is fitted onto the rotating shaft 2 at both ends in the axial direction. It is provided with a pair of cylindrical core pressers 7, 7 which are fixed under narrow pressure.

Note that since the motor shown in FIGS. 2 and 3(a) and (b) is classified as an IPM, a plurality of permanent magnets 3 are embedded in the core 6 at intervals in the circumferential direction. . In the case of a motor classified as such an IPM, it is desirable to reduce the gap between the rotor 1 and the stator in order to improve rotational performance. In this case, all permanent magnets 3 are connected to the core. 6 is buried near the outer peripheral surface.

Recesses 6a corresponding to the recesses 5a shown in FIGS. 1(a) and 1(b) are provided at a plurality of locations in the circumferential direction on the outer peripheral surface of each core presser 6. The motor rotor 1 of this embodiment can also be manufactured in the same manner as the motor rotor 1 shown in FIGS. 1(a) and 1(b). That is, a prepreg sheet 8 in which a fiber base material is impregnated with a thermosetting resin is wrapped around the outer periphery of the core 6 and the pair of core holders 7, and is heated and cured to form a reinforcing tube 4 extending in the axial direction. Further, a plurality of circumferential locations of the reinforcing tube 4 enter into each depression 7a of the core presser 7, and the reinforcing tube 4 is adhered to the outer circumferential surfaces of the pair of core pressers 7 and the core 6. Therefore, multiple locations in the circumferential direction of the reinforcing tube 4 that have entered each depression 7a function as anchors, and the adhesive strength between the core 6 and the pair of core holders 7, 7 and the reinforcing tube 4 becomes sufficiently high, even during high-speed rotation. All the permanent magnets 3 can be prevented from scattering outside the core 6. The manufactured rotor 1 of the motor can be an inexpensive general-purpose product. These things also apply to generators.

In addition, in the rotor 1 of the motor of this embodiment, including the case of a generator, the recesses 7a formed in the core holders 7, 7 can also be provided in the core 6. In this case as well, the depressions are provided at a plurality of locations in the circumferential direction of the core 6. The positions of the recesses formed in the core 6 in this way can be arbitrary in the axial direction of the core 6, and for example, they can be arranged at predetermined intervals in the axial direction. In this case, each depression is formed by, for example, forming a notch with a shape corresponding to the radial cross-sectional shape of the depression in the outer peripheral edge of a plurality of electromagnetic steel sheets located at the recessed location of each depression. be done.

Next, another embodiment of the rotor of the electric motor classified as the IPM will be described with reference to FIGS. 4, 5(a), 5(b), and 6. In this embodiment, like the embodiment shown in FIGS. 2 and 3(a), (b), the same parts and parts as in the embodiment shown in FIGS. 1(a) and (b) are designated by the same reference numerals. , the explanation is omitted.

As shown in FIG. 4, the rotor 1 of the motor as an electric motor shown in FIGS. This is different from the motor rotor 1 shown in FIGS. 3(a) and 3(b). That is, a plurality of axially extending grooves 6a are formed in the core 6 and are located between the buried locations of the axially extending permanent magnets 3, which are embedded at intervals in the circumferential direction. Specifically, each groove 6a has a V-shaped cross section in the radial direction, and is formed at predetermined intervals in the circumferential direction of the core 6. Each groove 6a is formed by cutting out the outer peripheral edge of each electromagnetic steel plate forming the core 6 into a shape that matches the cross-sectional shape of each groove 6a, forming notches spaced apart in the circumferential direction, and cutting each electromagnetic steel plate into It can be formed by stacking them in the axial direction so that the notches coincide with each other.

Further, two permanent magnets 3 extending in the axial direction are buried in a portion of the core 6 closer to the outer circumferential surface thereof as a set. In each set, the two permanent magnets 3, 3 are spaced apart from each other so that a gap is formed between them. This arrangement is for suppressing a decrease in the strength of the core 6 due to embedding of the permanent magnets 3, 3 in a pair near the outer peripheral surface.

The motor rotor 1 shown in FIGS. 4, 5(a), 5(b), and 6 is different from the one shown in FIG. This is different from the motor rotor 1 shown in FIGS. 3(a) and 3(b). As the thermosetting resin forming the binder 9, for example, one that has good affinity with the thermosetting resin of the prepreg sheet 8 wound around the outer periphery of the core 6 is used. The same thermosetting resin as the prepreg sheet 8 can be used, and in this case, it is particularly suitable for improving the affinity.

Further, the binder 9 may be in a solid state or may be B-staged like the prepreg sheet 8. In any case, it is sufficient if the binder 9 does not fall off from each groove 6a after being inserted into each groove 6a. The shape of the solid binder 9 is such that it has a cross section that comes into close contact with each side surface of each groove 6a. Specifically, a triangular cross section is exemplified. Further, the binder 9 is inserted over the entire length of each groove portion 6a in the axial direction. However, the binder 9 does not necessarily have to be elongated and extend over the entire length of each groove 6a. It is also possible to insert a plurality of short binders 9 in the length direction of each groove 6a with or without intervals. When inserting a plurality of short binders 9 at intervals between two adjacent ones, the intervals should be set so that the parts that are melted when heating and curing the prepreg sheet 8 come into close contact and no gaps are formed. desirable.

Further, the binder 9 can be made to have a size such that when inserted into each groove 6a, the outer surface of the binder 9 protrudes radially outward from the outer peripheral surface of the core 6, in consideration of heat shrinkage due to heat curing. The protrusion margin in this case can be set based on the heat shrinkage rate specific to each thermosetting resin.

When manufacturing the motor rotor 1 shown in FIGS. 4, 5(a), 5(b), and 6, a binder 9 is placed in each groove 6a of the core 6, as shown in FIG. 5(a). is inserted, and the prepreg sheet 8 is wound around the outer periphery of the core 6 and the pair of core pressers 7, 7, as shown in FIG. 4(b). As shown in FIG. 6, the wrapped precursor of the rotor 1 has a binder 9 radially outward between the prepreg sheet 8 and the end of each core presser 7 located on the core 6 side. A void 10 is formed by the protrusion.

The subsequent steps are similar to those for the rotor 1 of the motor in other embodiments. Then, as shown in FIG. 5(c), the voids 10 shown in FIG. 6 disappear due to thermal contraction accompanied by melting of the binder 9 due to heat curing, and the reinforcing tubes extending in the axial direction are caused by heat curing of the prepreg sheet 8. 4 is formed. The reinforcing tube 4 is bonded to the pair of core holders 7 and the outer circumferential surface of the core 6, and is also bonded to each groove 6a of the core 6 via each binder 9 cured by heat. Therefore, even if the permanent magnet 3 is disposed near the outer peripheral surface of the core 6 in order to improve rotational performance, the strength of the core 6 in the rotor 1 is improved.

Furthermore, instead of entering the reinforcing tube 4 into the recesses 5a and 7a at multiple locations in the circumferential direction in other embodiments, the thermosetting resin binder 9 inserted into the groove 6a functions as an anchor, and the core 6 and The adhesive strength between the pair of core pressers 7, 7 and the reinforcing tube 4 becomes sufficiently high. Therefore, all the permanent magnets 3 can be prevented from scattering outward from the core 6 even during high-speed rotation. As in the other embodiments, the manufactured rotor 1 of the motor can be an inexpensive general-purpose product. These things also apply to generators.

Although the embodiments of the present invention have been described above with reference to the drawings, the present invention is not limited thereto. For example, the shape, size, number, and mounting position of the permanent magnet 3 on the outer peripheral surface of the rotating shaft 2 or the embedded position in the core 6, and the number and shape of the permanent magnet pieces 3a that are the constituent units of the permanent magnet 3, The size and material are not particularly limited. Moreover, the shape, size, number, and arrangement position of the recesses 5a provided in each magnet holder 5 are not particularly limited. This also applies to the depressions 7a formed in each core holder 7 or the depressions formed in each core 6. Furthermore, the same applies to the shape, size, and number of each groove portion 6a formed in the core 6. The type of fiber base material and thermosetting resin constituting the prepreg sheet 8 is also not particularly limited.

DESCRIPTION OF SYMBOLS 1... Motor rotor, 2... Rotating shaft, 3... Permanent magnet, 4... Reinforcement tube, 5... Magnet holder, 5a, 7a... Hollow, 6... Core, 6a... Groove, 7... Core holder, 8... Prepreg sheet , 9...Binder.

Claims (3)

A rotor for an electric motor, comprising a rotating shaft and a plurality of permanent magnets arranged in the axial direction and attached to the outer peripheral surface of the rotating shaft at intervals in the circumferential direction,
A reinforcing tube extending in the axial direction, which is formed by heating and curing a prepreg sheet in which a fiber base material is impregnated with a thermosetting resin, is in close contact with the outer peripheral surface of all permanent magnets,
A pair of magnet holders are provided at both ends of each permanent magnet in the axial direction, and are fitted onto the rotating shaft to tightly fix all the permanent magnets. is recessed,
The prepreg sheet is wrapped around the outer periphery of all the permanent magnets along with a pair of magnet holders, and multiple points in the circumferential direction of the reinforcing tube enter each depression, so that the reinforcing tube is adhered to the outer periphery of all the permanent magnets. A rotor for an electric motor characterized by: A rotating shaft, a cylindrical core extending in the axial direction and fitting onto the rotating shaft, and a pair of core holders located at both ends of the core in the axial direction and fitting onto the rotating shaft to fix the core under narrow pressure. , a rotor of an electric motor comprising a plurality of permanent magnets or secondary conductors arranged in the axial direction and spaced apart in the circumferential direction between the pair of core holders,
A permanent magnet or secondary conductor is embedded in the core,
A reinforcing tube extending in the axial direction, which is formed by heating and curing a prepreg sheet in which a fiber base material is impregnated with a thermosetting resin, is in close contact with the outer peripheral surface of the core and a pair of core holders,
Recesses are provided at multiple locations in the circumferential direction on the outer peripheral surface of the pair of core holders or the core,
A prepreg sheet is wrapped around the outer periphery of the pair of core holders and the core, and a reinforcing tube extending in the axial direction is formed by heating and curing. A rotor for an electric motor, characterized in that the rotor is bonded to an outer circumferential surface and to the outer circumferential surfaces of a pair of core holders. A rotating shaft, a cylindrical core extending in the axial direction and fitting onto the rotating shaft, and a pair of core holders located at both ends of the core in the axial direction and fitting onto the rotating shaft to fix the core under narrow pressure. , a rotor of an electric motor comprising a plurality of permanent magnets or secondary conductors arranged in the axial direction and spaced apart in the circumferential direction between the pair of core holders,
A permanent magnet or secondary conductor is embedded in the core,
A reinforcing tube extending in the axial direction, which is formed by heating and curing a prepreg sheet in which a fiber base material is impregnated with a thermosetting resin, is in close contact with the outer peripheral surface of the core and a pair of core holders,
A plurality of grooves extending in the axial direction are formed on the outer peripheral surface of the core and are located between the buried locations of each permanent magnet or each secondary conductor,
A thermosetting resin binder is inserted into each groove of the core, a prepreg sheet is wrapped around the core and each binder together with a pair of core holders, and a reinforcing tube extending in the axial direction is formed by heating and curing. An electric motor characterized in that the tube is bonded to the outer circumferential surface of the core and the outer circumferential surface of the pair of core holders, and the reinforcing tube is also bonded to each groove of the core via each heat-cured binder. rotor.

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