Electric motor rotor

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

[Technical Field]

[0001] The present invention relates to a rotor for an electric motor that includes a rotating shaft and a plurality of permanent magnets or secondary conductors that are arranged in the axial direction and are provided on the outer periphery of the rotating shaft at intervals in the circumferential direction. [Background technology]

[0002] Conventionally, a rotor for this type of electric motor is known in which an axially extending reinforcing tube formed by heat curing a prepreg sheet in which a thermosetting resin is impregnated into a fiber base material is tightly attached to the outer peripheral surfaces of all permanent magnets (see, for example, Patent Document 1).

[0003] Such motor rotors are required to prevent all permanent magnets from scattering outward from the rotating shaft even under centrifugal force during high-speed rotation. To meet this requirement, the adhesive strength of the reinforcing tube must be increased. Therefore, in the motor rotor described in Patent Document 1, a cylindrical reinforcing tube is prefabricated into which the rotating shaft with attached permanent magnets can be inserted, and the rotating shaft is hollow. The motor rotor is then fabricated using a technique known as cold fitting. A refrigerant such as liquid nitrogen is circulated through the hollow portion of the rotating shaft, causing the rotating shaft to shrink radially inward. The rotating shaft is then inserted into the reinforcing tube, the refrigerant flow is stopped, and the temperature of the rotating shaft is returned to room temperature, causing the rotating shaft to expand radially outward and return to its original size. The reinforcing tube is then tightly attached to the outer periphery of all permanent magnets. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-50925 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the rotor of the electric motor described in Patent Document 1 is manufactured using a special method called cold fitting, which requires not only a dedicated jig but also a jig for manufacturing the cylindrical reinforcing tube from a single piece of prepreg and a hollow rotating shaft. Therefore, there is considerable room for reexamination in order to make the rotor of the electric motor described in Patent Document 1 into an inexpensive, general-purpose product.

[0006] In view of the above, an object of the present invention is to provide a rotor for an electric motor that can be used as an inexpensive, general-purpose product while preventing all permanent magnets or all secondary conductors from scattering outward from the rotating shaft even during high-speed rotation. [Means for solving the problem]

[0012] In order to solve the above problems, The present invention ,times A rotor for an electric motor includes a rotating shaft, a cylindrical core that extends in the axial direction and fits onto the rotating shaft, a pair of core holders that are located at both axial ends of the core and fit onto the rotating shaft to clamp and fix the core, and a plurality of permanent magnets or secondary conductors that are arranged in the axial direction between the pair of core holders and spaced apart in the circumferential direction, the permanent magnets or secondary conductors being embedded in the core, and a reinforcing tube that extends in the axial direction and is formed by heat curing a prepreg sheet in which a fiber base material is impregnated with a thermosetting resin, is in close contact with the outer circumferential surfaces of the core and the pair of core holders. In the above, a plurality of grooves extending in the axial direction are formed on the outer peripheral surface of the core, positioned between the embedded locations of each permanent magnet or each secondary conductor, a binder made of a thermosetting resin is inserted into each groove of the core, a prepreg sheet is wrapped around the outer periphery of the core and each binder together with a pair of core holders, and a reinforcing tube extending in the axial direction is formed by heat curing, and this reinforcing tube is bonded to the outer peripheral surface of the core and the outer peripheral 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.

[0013] Original Clearly According ,each The thermosetting resin binder inserted into the groove functions as an anchor. ,KoThe adhesive strength between the core and the pair of core holders and the reinforcing tube is sufficiently high, and it is possible to prevent all of the permanent magnets or all of the secondary conductors from scattering outside the core even during high-speed rotation. The rotor of the electric motor manufactured can then be an inexpensive, general-purpose product. [Brief explanation of the drawings]

[0014] [Figure 1] 1A is an axial cross-sectional view showing the outline of a rotor of an electric motor according to a first comparative example of the present invention, and FIG. 1B is an AA cross-sectional view of the same comparative example. [Figure 2] FIG. 10 is an axial cross-sectional view showing an outline of a rotor of an electric motor according to a second comparative example of the present invention. [Figure 3] 2A is a cross-sectional view taken along line AA, schematically illustrating a process of winding a prepreg when producing the comparative example shown in FIG. 2; FIG. 2B is a cross-sectional view taken along line AA of the comparative example shown in FIG. [Figure 4] 1 is a radial cross-sectional view showing an outline of a rotating shaft, a core, and a permanent magnet in an embodiment of a rotor for an electric motor according to the present invention; [Figure 5] 5(a), (b), and (c) are radial cross-sectional views each showing a schematic diagram of each step in the fabrication of the embodiment shown in FIG. 4. [Figure 6] 5(b) and 5(c) are axial cross-sectional views showing an outline of a rotor precursor after the step shown in FIG. 5(b) and an outline of an embodiment of a rotor for an electric motor according to the present invention after the step shown in FIG. 5(c). DETAILED DESCRIPTION OF THE INVENTION

[0015] As shown in Figure 1(a)(b), First Comparative Exampleis an example of a rotor for an electric motor classified as an 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 circumferential surface of the rotating shaft 2 at circumferential intervals. The rotating shaft 2 is formed from a metal material containing iron or other magnetic substances. Specifically, each permanent magnet 3 is made up of a plurality of magnet pieces 3a, which form the constituent units of each permanent magnet 3, arranged in a line in the axial direction and attached to the outer circumferential surface of the rotating shaft 2 by the magnetic force of the magnet pieces 3a. The number of permanent magnets 3 and their attachment positions on the rotating shaft 2 are not particularly limited, as long as each permanent magnet 3 generates a magnetic field that can satisfy the required performance of the motor. Furthermore, the material from which the magnet pieces 3a are made is not particularly limited.

[0016] In addition, in the rotor 1, an axially extending reinforcing tube 4 formed by heat-curing a prepreg sheet in which a fiber substrate is impregnated with a thermosetting resin is in close contact with the outer circumferential surface of all permanent magnets 3. Regarding the prepreg sheet, the fiber substrate can be, for example, a woven or nonwoven fabric made of carbon fiber, silicon carbide fiber, Tyranno (SiTiC) fiber, Kevlar fiber, alumina fiber, boron fiber, or the like. The thermosetting resin can be, for example, an epoxy resin, a polyimide resin, or a polyether ether ketone resin. The reinforcing tube 4 formed from the prepreg sheet is preferably lightweight and strong enough to prevent all permanent magnets 3 from scattering outward from the rotating shaft 2 even during high-speed rotation. The fiber substrate and thermosetting resin are selected taking the above factors into consideration.

[0017] Furthermore, the rotor 1 is provided with a pair of magnet pressers 5, 5 located at both axial ends of each permanent magnet 3. These pressers fit onto the rotating shaft 2 to clamp and secure all of the permanent magnets 3. Recesses 5a are formed in multiple locations around the circumference of the outer circumferential surface of each magnet presser 5. Multiple locations around the circumference of the reinforcing tube 4 fit into these recesses 5a, and the reinforcing tube 4 is bonded to the outer circumferential surfaces of all of the permanent magnets 3 and to the outer circumferential surfaces of the pair of magnet pressers 5, 5 that face the permanent magnet 3. The bonding between all of the permanent magnets 3 and the pair of magnet pressers 5, 5 and the reinforcing tube 4 is achieved when the prepreg sheet, together with the pair of magnet pressers 5, 5, is wrapped around the outer circumferential surfaces of all of the permanent magnets 3 and heat-cured to form the reinforcing tube 4, and part of the thermosetting resin penetrates into the recesses 5a formed in each magnet presser 5 and hardens. The multiple circumferential points of the reinforcing tube 4 that fit into each recess 5a function as anchors, and the adhesive strength between all of the permanent magnets 3 and the pair of magnet holders 5, 5 and the reinforcing tube 4 is sufficiently high, comparable to the adhesive strength achieved by conventional cold fitting.

[0018] More specifically, the axial width of the prepreg sheet is set to a length extending axially outward beyond all of the recesses 5a of each magnet presser 5. The prepreg sheet is pulled out from the original roll and, in a so-called B-stage state, is wound with a predetermined tension around the outer periphery of all of the permanent magnets 3 together with the pair of magnet pressers 5. When bonding the reinforcing tube 4 to all of the permanent magnets 3 and the pair of magnet pressers 5, the precursor, in which the prepreg sheet is wrapped around the outer periphery of all of the permanent magnets 3 together with the pair of magnet pressers 5, is placed inside, for example, a bag or container capable of being decompressed. The decompression causes the prepreg sheet to deform so that it conforms to the inner surface of each recess 5a of each magnet presser 5 and the outer periphery of each permanent magnet 3. The precursor is then heated to the curing temperature of the thermosetting resin in the prepreg sheet. This heating may be performed continuously while the prepreg sheet is still stored inside the bag or container, or it may be performed in a batch process in which the prepreg sheet is removed from the bag or container and then re-stored inside a heat treatment chamber or the like for heating.

[0019] For example, First Comparative ExampleAs described above, the motor rotor 1 has a sufficiently high adhesive strength between all of the permanent magnets and the pair of magnet pressers 5, 5 and the reinforcing tube 4, and can prevent all of the permanent magnets 3 from scattering outward from the rotating shaft 2 even when the rotor 1 rotates at high speed. The motor rotor 1 is manufactured by using a pair of magnet pressers 5 that are fitted onto the rotating shaft 2 and have recesses 5a formed in multiple locations on the circumferential surface, and by wrapping the prepreg sheet, which will later become the reinforcing tube 4, around the outer periphery of all of the permanent magnets 3 together with the pair of magnet pressers 5, 5 and heat-curing the prepreg sheet, and therefore the motor rotor 1 can be an inexpensive, general-purpose product.

[0020] Figures 2 and 3(a) and (b) are classified as IPM. Second Comparative Example Motor rotation Child In addition, as shown in Figure 1(a)(b), First Comparative Example The same parts and parts are denoted by the same reference numerals and the description thereof will be omitted.

[0021] 2 and 3(a)(b) are also motors, but the permanent magnets 3 can be replaced with secondary conductors such as windings, in which case the motor becomes a generator. The rotor 1 of the motor shown in Figures 2 and 3(a)(b) includes a cylindrical core 6 fitted onto the rotating shaft 2, and a pair of cylindrical core holders 7, 7 that are fitted onto the rotating shaft 2 and clamp the core 6 at both axial ends.

[0022] 2 and 3(a) and (b) is classified as an IPM, and therefore the multiple permanent magnets 3 are embedded at circumferential intervals in the core 6. In the case of such an IPM motor, it is desirable to reduce the gap between the rotor 1 and the stator in order to improve rotation performance. In this case, all of the permanent magnets 3 are embedded in the core 6 near the outer periphery.

[0023] Each core holder 7 At a plurality of locations in the circumferential direction on the outer peripheral surface of the 7 a is recessed. Second Comparative ExampleThe rotor 1 of this motor can be fabricated in the same manner as the rotor 1 of the motor shown in Figures 1(a) and 1(b). Specifically, a prepreg sheet 8, composed of a fiber matrix impregnated with a thermosetting resin, is wrapped around the core 6 and a pair of core holders 7, and the prepreg sheet 8 is heated and cured to form a reinforcing tube 4 extending in the axial direction. The reinforcing tube 4 is inserted into each recess 7a of the core holder 7 at multiple locations along the circumferential direction, and the reinforcing tube 4 is bonded to the outer surfaces of the pair of core holders 7 and the core 6. Therefore, the multiple circumferential locations of the reinforcing tube 4 inserted into each recess 7a function as anchors, sufficiently increasing the adhesive strength between the core 6 and the pair of core holders 7, 7 and the reinforcing tube 4, preventing all of the permanent magnets 3 from scattering outside the core 6 even during high-speed rotation. The fabricated motor rotor 1 can be an inexpensive, general-purpose product. The same applies to generators.

[0024] In addition, Second Comparative Example In the rotor 1 of the motor, including the generator, each of the recesses 7a recessed in the core holders 7, 7 can also be provided in the core 6. In this case, the recesses are also provided at multiple locations in the circumferential direction of the core 6. The positions of the recesses thus recessed in the core 6 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 recess is formed, for example, by forming notches in a shape corresponding to the radial cross-sectional shape of the recess in the outer peripheral edge portions of multiple electromagnetic steel sheets located at the recessed location of each recess.

[0025] 4, 5(a), (b), (c), and 6, the above-mentioned IPM-classified The present invention Electric motor rotor fruit This embodiment will be described. This embodiment also uses the same configuration as shown in FIG. Second Comparative Example Similarly, as shown in Fig. 1(a)(b), First Comparative Example The same parts and parts are denoted by the same reference numerals and the description thereof will be omitted.

[0026] As shown in FIG. 4, the rotor 1 of the motor as an electric motor shown in FIGS. 4, 5(a), 5(b), 5(c), and 6 differs from the rotor 1 of the motor shown in FIGS. 2 and 3(a) and 3(b) in the shape and structure of the core 6. That is, the core 6 has a plurality of axially extending grooves 6a formed between the embedded locations of the axially extending permanent magnets 3 that are embedded at circumferential intervals. Specifically, each groove 6a has a V-shaped radial cross section and is formed at predetermined intervals around the core 6. The grooves 6a can be formed by cutting out the outer periphery of each electromagnetic steel sheet forming the core 6 in a shape that matches the cross-sectional shape of each groove 6a, forming notches at intervals around the circumferential direction, and stacking the electromagnetic steel sheets in the axial direction so that the notches match.

[0027] Furthermore, the permanent magnets 3 extending in the axial direction are embedded in pairs near the outer periphery of the core 6. In each pair, the two permanent magnets 3, 3 are spaced apart to form a gap between them. This arrangement is intended to prevent a decrease in the strength of the core 6 due to the pair of permanent magnets 3, 3 being embedded near the outer periphery.

[0028] The motor rotor 1 shown in Figures 4, 5(a), 5(b), 5(c), and 6 also differs from the motor rotor 1 shown in Figures 2 and 3(a) and 3(b) in that a binder 9 made of a thermosetting resin is inserted into each groove 6a. The thermosetting resin forming the binder 9 is, 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. The same thermosetting resin as that of the prepreg sheet 8 can be used, and in this case, it is particularly suitable for achieving good affinity.

[0029] The binder 9 may be solid or in a B-stage state similar to the prepreg sheet 8. In either case, it is sufficient that the binder 9 does not fall out of each groove 6a after insertion into the groove 6a. The shape of the solid binder 9 has a cross section that closely contacts each side surface of each groove 6a. Specific examples include a triangular cross section. The binder 9 is inserted over the entire axial length of each groove 6a. However, the binder 9 does not necessarily have to be long enough to extend over the entire length of each groove 6a. Multiple short binders 9 can also be inserted into each groove 6a with or without spacing between them in the longitudinal direction. When multiple short binders 9 are inserted with spacing between adjacent ones, it is desirable to set the spacing so that the melted portions adhere to each other when the prepreg sheet 8 is heat-cured, preventing gaps from forming.

[0030] Furthermore, taking into consideration thermal shrinkage due to heat curing, the binder 9 can be sized so that when inserted into each groove 6a, its outer surface protrudes radially outward from the outer circumferential surface of the core 6. In this case, the protrusion margin can be set based on the thermal shrinkage rate specific to each thermosetting resin.

[0031] When manufacturing the rotor 1 of the motor shown in Figures 4, 5(a), 5(b), 5(c), and 6, a binder 9 is inserted into each groove 6a of the core 6 as shown in Figure 5(a), and a prepreg sheet 8 is wound around the outer periphery of the core 6 and a pair of core holders 7, 7 as shown in Figure 4(b). After the winding, the precursor of the rotor 1 has gaps 10 formed between the prepreg sheet 8 and the ends of each core holder 7 located on the core 6 side due to the binder 9 protruding radially outward, as shown in Figure 6.

[0032] The subsequent process is Comparative ExampleThe manufacturing process is similar to that of the rotor 1 of the motor of the present invention. Then, as shown in FIG. 5(c), the gaps 10 shown in FIG. 6 disappear due to thermal shrinkage caused by melting of the binder 9 during heat curing, and the reinforcing tube 4 extending in the axial direction is formed by the heat curing of the prepreg sheet 8. The reinforcing tube 4 is then bonded to the pair of core holders 7, 7 and the outer peripheral surface of the core 6, and is also bonded to each groove 6a of the core 6 via each heat-cured binder 9. Therefore, even if the permanent magnets 3 are arranged near the outer peripheral surface of the core 6 to improve rotation performance, the strength of the core 6 in the rotor 1 is improved.

[0033] Also, Comparative Example Instead of the permanent magnets 3 entering the recesses 5a, 7a at multiple locations in the circumferential direction of the reinforcing tube 4, the thermosetting resin binder 9 inserted into the groove 6a functions as an anchor, and the adhesive strength between the core 6 and the pair of core holders 7, 7 and the reinforcing tube 4 is sufficiently high. Therefore, it is possible to prevent all of the permanent magnets 3 from scattering out of the core 6 even during high-speed rotation. Comparative Example Similarly, the rotor 1 of the manufactured motor can be an inexpensive general-purpose product. The same applies to the generator.

[0034] 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, there are no particular limitations on the shape, size, number, and mounting position of the permanent magnets 3 on the outer circumferential surface of the rotating shaft 2 or the position of embedding them in the core 6, and on the number, shape, size, and material of the permanent magnet pieces 3a, which are the constituent units of the permanent magnets 3. ,Ko The shape, size and number of the grooves 6a formed in the hole 6 are also Not particularly limited The types of fiber base material and thermosetting resin that make up the prepreg sheet 8 are not particularly limited. [Explanation of symbols]

[0035] 1...electric motor rotor, 2...rotating shaft, 3...permanent magnet, 4...reinforcing tube, 5...magnet holder, 5a, 7a...recess, 6...core, 6a...groove, 7...core holder, 8...prepreg sheet, 9...binder

Claims

[Claim 1] A rotor of an electric motor comprising: a rotating shaft; a cylindrical core extending in the axial direction and fitted onto the rotating shaft; a pair of core holders located at both axial ends of the core and fitted onto the rotating shaft to clamp and fix the core; and a plurality of permanent magnets or secondary conductors arranged axially between the pair of core holders and spaced apart in the circumferential direction, A permanent magnet or secondary conductor is embedded in the core, The reinforcing tube is formed by heat curing a prepreg sheet in which a fiber base material is impregnated with a thermosetting resin, and extends in the axial direction. The reinforcing tube is in close contact with the outer peripheral surfaces of the core and a pair of core holders. A plurality of grooves are formed on the outer peripheral surface of the core, the grooves being positioned between the respective permanent magnets or secondary conductors and extending in the axial direction, A rotor for an electric motor, characterized in that 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 heat curing, this reinforcing tube is bonded to the outer surface of the core and the outer 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.

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