Rotor for an asynchronous motor and asynchronous motor

Abstract

Rotor (100-4; 100-6D; 100-7D; 100-8D) for an asynchronous motor, wherein the rotor has: a rotor core (1), a shaft (2) which passes through the rotor core (1), an annular end ring (3-1, 3-2) which is arranged in an end region of the rotor core (1), and a ring-shaped reinforcement element (4-1, 4-2) arranged between the shaft (2) and an inner circumferential region (3a) of the end ring (3-1, 3-2) and comprising an outer circumferential region (4a) that is in contact with the end ring (3-1, 3-2), wherein a first projecting area (3b) which is arranged on the inner circumferential area (3a) of the end ring (3-1, 3-2) is fitted into a first groove area (4b) which is arranged in the outer circumferential area (4a) of the reinforcement element (4-1, 4-2), characterized in that where the outer circumferential region (4a) of the reinforcement element (4-1, 4-2) has an outer diameter dimension (OD1) of an outer circumferential region (4a2) on one side of the rotor core (1) with respect to the first groove region (4b) larger than an outer diameter dimension (OD2) of an outer circumferential region (4a3) on a side opposite the rotor core (1) with respect to the first groove region (4b).

Description

Area

[0001] The present invention relates to a rotor for an asynchronous motor and an asynchronous motor. background

[0002] In recent years, the need to increase the speeds of asynchronous motors used in machine tools has increased. To meet this demand, a rotor for an asynchronous motor must have sufficient strength to withstand the centrifugal force generated at high rotational speeds. A conventional rotor disclosed in patent document JP 2015-159696 A includes a rotor core, a conductor bar disposed in the rotor core, a closure ring, which is a short-circuit ring disposed at one end portion of the rotor core and connected to the conductor bar, and a reinforcement member covering the closure ring. The reinforcement member is made of a material stiffer than that of the closure ring and has an outer annular portion fixed to the outer peripheral portion of the closure ring.The inner peripheral portion of the outer annular portion is in contact with the outer peripheral portion of the end ring. In the conventional rotor disclosed in patent document JP 2015-159696 A, the end ring is prevented from deforming due to centrifugal force by allowing the outer annular portion of the reinforcement member to be in contact with the outer peripheral portion of the end ring.

[0003] A rotor disclosed in patent document JP S59-35554 A discloses a structure in which a reinforcement element is arranged on an inner peripheral portion of a cover ring. This patent document JP S59-35554 A discloses the features of the preambles of the independent claims.

[0004] Patent document WO 2015 / 151362 A1 discloses a rotor for an asynchronous motor comprising a plurality of lead bars arranged at regular intervals along the circumferential direction of a rotor core, short-circuit rings connected to the ends of the lead bars, and reinforcing covers having axially contacting surfaces with axially contacting end surfaces of the short-circuit rings. Technical problem

[0005] The conventional rotor disclosed in patent document JP 2015 - 159 696 A has a problem that when the outer annular portion of the reinforcement member expands in the radial direction due to the end ring at a high rotational speed of the rotor to undergo plastic deformation, deformation of the end ring can no longer be prevented and therefore the rotor must be replaced before the end of its designed service life in some cases.

[0006] The problem that the reinforcement element expands in the radial direction due to the end ring does not occur in the rotor disclosed in patent document JP S59-35 554 A, and deformation of the end ring due to centrifugal force is prevented, but not sufficiently.

[0007] The present invention has been made in view of the above, and an object of the present invention is to provide a rotor for an asynchronous motor in which a shortening of the service life of the rotor can be prevented. Solution to the problem

[0008] The above object is achieved by combining the features of the independent claims. Preferred developments can be found in the dependent claims. Advantageous effects of the invention

[0009] A rotor for an asynchronous motor according to the present invention has the effect of preventing a shortening of the service life of the rotor. Short description of the characters Fig. 1 shows a cross-sectional view of an asynchronous motor according to a first embodiment. Fig. 2 shows a cross-sectional view of a rotor for the asynchronous motor according to the first embodiment. Fig. 3 shows a cross-sectional view in the direction of arrows III-III of Fig. 2. Fig. 4 shows a perspective view of a Fig. 2 shown end ring. Fig. 5 shows a perspective view of a Fig. 2 shown reinforcement element. Fig. 6 shows a cross-sectional view of a comparative example of the rotor for the induction motor according to the first embodiment. Fig. Figure 7 shows a representation of the end ring deformation when the Fig. 6 shown rotor of the comparison example rotates. Fig. 8 is a diagram showing the end ring deformation when the rotor for the induction motor according to the first embodiment rotates. Fig. 9 shows a cross-sectional view of a rotor for an asynchronous motor according to a second embodiment. Fig. 10 shows a cross-sectional view of a rotor for an asynchronous motor according to a third embodiment. Fig. 11 shows a cross-sectional view of a rotor for an asynchronous motor according to a fourth embodiment of the present invention. Fig. 12 shows a cross-sectional view of a rotor for an asynchronous motor according to a fifth embodiment of the present invention. Fig. 13 shows a diagram illustrating a first modification of the Fig. 2 shown rotor. Fig. 14 shows a diagram illustrating a first modification of the Fig. 9 shown rotor. Fig. 15 shows a diagram illustrating a first modification of the Fig. 10 shown rotor. Fig. 16 shows a diagram illustrating a first modification of the Fig. 11 shown rotor. Fig. 17 shows a diagram illustrating a first modification of the Fig. 12 shown rotor. Fig. Figure 18 is a diagram illustrating a second modification of the Fig. 2 shown rotor. Fig. 19 shows a diagram illustrating a second modification of the Fig. 9 shown rotor. Fig. Figure 20 is a diagram illustrating a second modification of the Fig. 10 shown rotor. Fig. 21 shows a diagram illustrating a second modification of the Fig. 11 shown rotor. Fig. 22 shows a diagram illustrating a second modification of the Fig. 12 shown rotor. Fig. Figure 23 is a diagram illustrating a third modification of the Fig. 2 shown rotor. Fig. Figure 24 is a diagram illustrating a third modification of the Fig. 9 shown rotor. Fig. Figure 25 shows a representation of the illustration of a third modification of the Fig. 10 shown rotor. Fig. Figure 26 is a diagram illustrating a third modification of the Fig. 11 shown rotor. Fig. Figure 27 shows a diagram illustrating a third modification of the Fig. 12 shown rotor. Fig. Figure 28 is a diagram illustrating a fourth modification of the Fig. 2 shown rotor. Description of embodiments

[0010] Below, a rotor for an asynchronous motor and an asynchronous motor according to embodiments of the present invention will be described in detail with reference to the figures. The present invention is not limited to the embodiments. Not all embodiments and modifications are claimed. First embodiment

[0011] Fig. 1 shows a cross-sectional view of an asynchronous motor according to a first embodiment. Fig. 2 shows a cross-sectional view of a rotor of the asynchronous motor according to the first embodiment. Fig. 3 shows a cross-sectional view in the direction of arrows III-III of Fig. 2. Fig. 4 shows a perspective view of a Fig. 2 shown end ring. Fig. 5 shows a perspective view of a Fig. 2 shown reinforcement element.

[0012] One in Fig. The induction motor 300 according to the first embodiment, illustrated in FIG. 1, includes a stator 200 and a rotor 100-1 disposed within the stator 200. The stator 200 has a tubular casing 210 and a stator core 220 disposed within the casing 210. The stator core 220 is formed by stacking a plurality of annular thin plates, punched from a non-grain-oriented electrical steel base material, in the axial direction D1 of a central axis AX of a rotor core 1. The thin plates are fixed to each other by crimping, welding, or bonding. The plurality of windings 230 are disposed on the stator core 220. The winding ends on one side of the windings 230 in the axial direction D1 protrude from one end surface of the stator core 220 in the axial direction D1.The winding ends on the other side of the windings 230 in the axial direction D1 protrude from the other end surface of the stator core 220 in the axial direction D1.

[0013] As from Fig. As shown in Fig. 2, the rotor 100-1 for the induction motor according to the first embodiment includes the tubular rotor core 1, a shaft 2, and an annular end ring 3-1 disposed at one end portion 1b1 of the rotor core 1 in the axial direction D1 of the central axis AX. The rotor 100-1 further includes an annular end ring 3-2 disposed at the other end portion 1b2 in the axial direction D1. The rotor 100-1 further includes an annular reinforcement member 4-1 disposed between an inner peripheral portion 3a of the end ring 3-1 and the shaft 2 and having an outer peripheral portion 4a in contact with the inner peripheral portion 3a of the end ring 3-1.The rotor 100-1 further includes an annular reinforcement element 4-2 disposed between the inner peripheral portion 3a of the end ring 3-2 and the shaft 2, and including the outer peripheral portion 4a in contact with the inner peripheral portion 3a of the end ring 3-2. The end ring 3-1 and the end ring 3-2 may hereinafter be referred to as end rings 3-1, 3-2, and the reinforcement element 4-1 and the reinforcement element 4-2 may hereinafter be referred to as reinforcement elements 4-1, 4-2.

[0014] Each of the end rings 3-1, 3-2 has a first protrusion portion 3b, which is annular and arranged on the inner peripheral portion 3a. The reinforcing elements 4-1, 4-2 each have a first groove portion 4b, which is annular and arranged in the corresponding outer peripheral portion 4a. The first groove portion 4b has a shape into which the first protrusion portion 3b fits. The outer diameter of the first groove portion 4b corresponds to the inner diameter of the first protrusion portion 3b. The width of the first groove portion 4b in the axial direction D1 corresponds to the width of the first protrusion portion 3b in the axial direction D1.

[0015] The rotor core 1 is formed by stacking a plurality of ring-shaped thin plates punched from a non-grain-oriented electrical steel base material in the axial direction D1. The thin plates are fastened to each other by crimping, welding, or adhesive bonding. The rotor core 1 has a plurality of core slots 5 located near the outer peripheral surface of the rotor core 1 and arranged in the axial circumferential direction D2 of the central axis AX, and conductor bars 6 located in the core slots 5. Each of the core slots 5 extends in the axial direction D1 and passes through the rotor core 1 from one end portion 1b1 to the other end portion 1b2.

[0016] Each of the core slots 5 located in the rotor core 1 extends obliquely to the axial line circumferential direction D2. One end portion 6a of the conductor bar 6, which is arranged in the respective core slot 5, is connected in the axial line direction D1 to an end portion 3c of the end ring 3-1 on the rotor core 1 side. The other end portion 6b of the conductor bar 6, which is arranged in the respective core slot 5, is connected in the axial line direction D1 to the end portion 3c of the end ring 3-2 on the rotor core 1 side.

[0017] Examples of materials for the end ring 3-1, the end ring 3-2, and the conductor bar 6 may include conductor materials such as aluminum, an aluminum alloy, copper, and a copper alloy. The end rings 3-1, 3-2 are formed by die-casting such a conductor material. The outer diameters of the end rings 3-1, 3-2 correspond to the outer diameter of the rotor core 1. The inner peripheral portion 3a of the end ring 3-1 is in contact with the outer peripheral portion 4a of the reinforcement member 4-1. The inner peripheral portion 3a of the end ring 3-2 is in contact with the outer peripheral portion 4a of the reinforcement member 4-2.

[0018] The centrifugal force acting on an object depends not only on the radius and angular velocity of the object, but also on the object's mass. The reinforcement elements 4-1, 4-2 must resist deformation caused by the centrifugal force in order to prevent deformation of the end rings 3-1, 3-2 resulting from centrifugal force and thermal expansion. Therefore, a material used for the reinforcement elements 4-1, 4-2 has a higher tensile strength per unit mass than the material of the end rings 3-1, 3-2. Specifically, iron, titanium, and carbon fiber reinforced plastic can be cited as examples of materials for the reinforcement elements 4-1, 4-2. The reinforcement elements 4-1, 4-2 each have a through hole 4c. The shaft 2 extends through the through hole 4c of each reinforcement element 4-1, 4-2 and a through hole 1a of the rotor core 1.

[0019] In manufacturing the rotor 100-1, first, the armor member 4-2 is attached to one end portion 1b1 of the rotor core 1, and the armor member 4-2 is attached to the other end portion 1b2 of the rotor core 1. Then, the end rings 3-1, 3-2 are formed by die-casting a conductive material so that the armor members 4-1 and 4-2 and the end rings 3-1, 3-2 are integrally formed, with each of the first projection portions 3b being fitted into a corresponding one of the first groove portions 4b. A structure in which the armor members 4-1, 4-2 and the end rings 3-1, 3-2 are integrally formed here refers to a structure in which the first projection portion 3b of each end ring 3-1, 3-2 is in contact with and fitted into the first groove portion 4b of a corresponding one of the armor members 4-1, 4-2.That is, this refers to a structure in which the first protrusion portions 3b are each fitted into the corresponding one of the first groove portions 4b. Next, the through-hole 4c of the reinforcement member 4-1, the through-hole 4c of the reinforcement member 4-2, and the through-hole 1a of the rotor core 1 are finished to have identical dimensions, and the shaft 2 is press-fitted into the through-holes 4c and the through-hole 1a. In the first embodiment, the shaft 2 is press-fitted into the through-holes 4c and the through-hole 1a.

[0020] By integrally forming the reinforcement members 4-1, 4-2 and the end rings 3-1, 3-2, the time required to attach the reinforcement members 4-1, 4-2 and the end rings 3-1, 3-2 to the shaft 2 is reduced compared to the case where the reinforcement members 4-1, 4-2 and the end rings 3-1, 3-2 are individually attached to the shaft 2. By fastening the reinforcement members 4-1, 4-2 and the end rings 3-1, 3-2 to the shaft 2 by means of a shrink fit, the frictional force between the inner peripheral portions of the through holes 4c in the reinforcement members 4-1, 4-2 and the outer peripheral portion of the shaft 2 is increased compared to the case where a shrink fit is not used. This friction force prevents the reinforcement elements 4-1, 4-2 from moving in the axis line direction D1 when the rotor 100-1 rotates at high speed and is subject to thermal expansion.This improves the reinforcement effect of the reinforcement elements 4-1, 4-2 on the end rings 3-1, 3-2 compared to the case where there is no shrink fit. The reinforcement effect is an effect of the reinforcement elements 4-1, 4-2 that prevents deformation of the end rings 3-1, 3-2 resulting from centrifugal force and thermal expansion. The reinforcement effect of the rotor 100-1 is described with reference to the

[0021] Fig. 6 to 8 are described in detail. Fig. 6 shows a cross-sectional view of a comparative example of the rotor of the asynchronous motor according to the first embodiment. Fig. The rotor 100A shown in Figure 6 differs from the one shown in Fig. 2 illustrated rotor 100-1 in the following points. (1) The rotor 100A has, instead of the Fig. 2 shown end rings 3-1, 3-2 end rings 3-1A, 3-2A. The inner circumferential areas 3a of the end rings 3-1A, 3-2A do not have the Fig. 2 shown first projection areas 3b. (2) The rotor 100A has, instead of the Fig. 2 shown reinforcing elements 4-1, 4-2 reinforcing elements 4-1A, 4-2A. The outer peripheral areas 4a of the reinforcing elements 4-1A, 4-2A do not have the Fig. 2 shown first groove areas 4b.

[0022] The outer diameters of the outer peripheral regions 4a of the reinforcing element 4-1A and the reinforcing element 4-2A correspond to the inner diameters of the inner peripheral regions 3a of the end ring 3-1A and the end ring 3-2A, respectively. The widths of the reinforcing element 4-1A and the reinforcing element 4-2A in the axial direction D1 correspond to the widths of the end ring 3-1A and the end ring 3-2A, respectively, in the axial direction D1.

[0023] In manufacturing the rotor 100A, first, the armor member 4-1A is attached to one end portion 1b1 of the rotor core 1, and the armor member 4-2A is attached to the other end portion 1b2 of the rotor core 1. Then, the end rings 3-1A, 3-2A are formed by die-casting a conductive material so that the end ring 3-1A and the armor member 4-1A are integrally formed, and the end ring 3-2A and the armor member 4-2A are integrally formed. Then, the through-hole 4c of the armor member 4-1A, the through-hole 4c of the armor member 4-2A, and the through-hole 1a of the rotor core 1 are subjected to final machining to have identical dimensions, and the shaft 2 is shrink-fitted into the through-holes 4c and the through-hole 1a.

[0024] Fig. Figure 7 shows a representation of the rotation of the rotor according to the Fig. 6 illustrates a comparative example of a deforming end ring. In Fig. 7, the contour of the end ring 3-1A observed when the rotor 100A is stationary is shown with a solid line and the contour of the deformed end ring 3-1A observed when the rotor 100A is rotating at high speed is shown with a dashed line.

[0025] Due to the integral design of the end ring 3-1A and the reinforcing element 4-1A, the outer peripheral region 4a of the reinforcing element 4-1A is in contact with the inner peripheral region 3a of the end ring 3-1A, whereby a frictional force is generated between the outer peripheral region 4a of the reinforcing element 4-1A and the inner peripheral region 3a of the end ring 3-1A. When the rotor 100A is rotated and subject to thermal expansion, this frictional force counteracts a deformation of the end ring 3-1A. When the rotor 100A rotates at high speed and undergoes thermal expansion, a force acts on the end ring 3-1A that expands the end ring 3-1A outward in the radial direction D3.The end ring 3-1A deforms with the connection point with the conductor bar 6 acting as a bearing point; therefore, the inner peripheral portion of the end ring 3-1A moves in the axial direction D1 against the above-described friction force, and the outer peripheral portion of the end ring 3-1A moves in the radial direction D3.

[0026] Specifically, the degree of deformation of the end ring 3-1A increases with the increase in the rotational speed of the rotor 100A; as a result, the amplitude of the stress generated in the end ring 3-1A increases compared to the case where the rotational speed of the rotor 100A is low. Furthermore, each time the rotor 100A is rotated and stopped again, or each time the rotational speed of the rotor 100A changes, additional stress is added to the connection point between the end ring 3-1A and the conductor bar 6 due to centrifugal force and thermal expansion, thereby accelerating fatigue at the connection point. Furthermore, repeated rotation and stopping of the rotor 100A causes the inner diameter and outer diameter of the end ring 3-1A to repeatedly expand and contract, thereby accelerating fatigue in the end ring 3-1A.Therefore, in some cases, the 100A rotor must be replaced before it has reached its intended service life.

[0027] Fig. Figure 8 shows a representation of the end ring deforming during rotation of the rotor for the asynchronous motor according to the first embodiment. In Fig. In Figure 8, the contour of the end ring 3-1 observed when the rotor 100-1 is stationary is shown with a solid line, and the deformed end ring 3-1 observed when the rotor 100-1 is rotating at high speed is shown with a dashed line. In the rotor 100-1, the first projection portion 3b and the first groove portion 4b are integrally formed, and the rotor 100-1 has an interlocking structure in which the first projection portion 3b is fitted into the first groove portion 4b.

[0028] The interlocking structure increases the area of ​​contact between the inner peripheral portion 3a of the end ring 3-1 and the outer peripheral portion 4a of the reinforcing element 4-1, so that it is larger than in the Fig. 7. As a result, the frictional force between the inner peripheral region 3a of the end ring 3-1 and the outer peripheral region 4a of the reinforcing element 4-1 is increased so that it is greater than in the rotor 100A shown in Fig. Rotor 100A shown in Figure 7.

[0029] In addition, the interlocking structure causes the first projection portion 3b to be caught in the first groove portion 4b when the end ring 3-1 moves in the axial direction D1. Therefore, the amount of deformation of the end ring 3-1 in the axial direction D1 and in the radial direction D3 is smaller than in the Fig. 7. Therefore, the reinforcement effect of the reinforcement elements 4-1, 4-2 on the end rings 3-1, 3-2 is greater in the first embodiment than in the Fig. 7, whereby the amplitude of the stress generated in the end rings 3-1, 3-2 is reduced and thereby the fatigue resistance of the end rings 3-1, 3-2 can be improved.

[0030] In the rotor 100-1 according to the first embodiment, when the rotor 100-1 rotates at high speed, plastic deformation of an outer annular portion of a reinforcing member does not occur as in the conventional rotor described in Patent Document JP 2015-159696 A, and a decrease in the reinforcing effect on the end rings 3-1, 3-2 is prevented, thereby preventing a shortening of the service life of the rotor 100-1.

[0031] The number of the above-described intermeshing structures provided by the rotor 100-1 according to the first embodiment is one at each of the end portions of the shaft 2, but the number of intermeshing structures provided at each of the end portions of the shaft 2 may be two or more. The rotor 100-1 according to the first embodiment has the intermeshing structure at each of the end portions of the shaft 2, although the intermeshing structure may be provided at only one of the end portions of the shaft 2 if the end portions of the shaft 2 are asymmetrical. Even with such a configuration, an effect of preventing deformation of the end ring 3-1 and the end ring 3-2 at least at the relevant location is achieved.

[0032] In the rotor 100-1 according to the first embodiment, the first groove portion 4b and the first protrusion portion 3b are annular. However, the first groove portion 4b may be formed as a plurality of recesses arranged in each of the reinforcement members 4-1, 4-2 in the axial circumferential direction D2, and the first protrusion portion 3b may be formed as a plurality of protrusions arranged in each of the end rings 3-1, 3-2 in the axial circumferential direction D2. Note that the deformation of the end rings 3-1, 3-2 in the axial circumferential direction D2 is uniformly prevented, and thus, the effect on extending the service life of the rotor 100-1 is best when the first groove portion 4b and the first protrusion portion 3b are annular. Second embodiment

[0033] Fig. 9 shows a cross-sectional view of a rotor of an induction motor according to a second embodiment. A rotor 100-2 according to the second embodiment differs from the rotor 100-1 according to the first embodiment in the following points. (1) The end rings 3-1, 3-2 of the rotor 100-2 each have a plurality of first protrusion portions 3b. The protrusion portions 3b formed in the end ring 3-1 are spaced apart from each other in the axial direction D1 and arranged on the inner peripheral portion 3a of the end ring 3-1. The first protrusion portions 3b formed in the end ring 3-2 are spaced apart from each other in the axial direction D1 and arranged on the inner peripheral portion 3a of the end ring 3-2. (2) The reinforcement elements 4-1, 4-2 of the rotor 100-2 each have a plurality of first groove portions 4b. The first groove portions 4b formed in the reinforcement element 4-1 are spaced apart from one another in the axial direction D1 and arranged in the outer peripheral region 4a of the reinforcement element 4-1. The first groove portions 4b formed in the reinforcement element 4-2 are spaced apart from one another in the axial direction D1 and arranged in the outer peripheral region 4a of the reinforcement element 4-2.

[0034] The end rings 3-1, 3-2 are formed by die-casting a conductor material. In this way, the end rings 3-1, 3-2 and the armoring elements 4-1, 4-2 are integrally formed. The second embodiment has an interlocking structure in which the first protrusion portions 3b are fitted into the first groove portions 4b. This increases the contact area between the inner peripheral portions 3a of the end rings 3-1, 3-2 and the outer peripheral portions 4a of the armoring elements 4-1, 4-2 to be larger than in the first embodiment, resulting in an increase in the frictional forces between the inner peripheral portions 3a of the end rings 3-1, 3-2 and the outer peripheral portions 4a of the armoring elements 4-1, 4-2 to be larger than in the first embodiment.Therefore, the extent of deformation of the end rings 3-1, 3-2 in the axial direction D1 and in the radial direction D3 is smaller than in the first embodiment. Therefore, the second embodiment is expected to further extend the fatigue life of the end rings 3-1, 3-2. Third embodiment

[0035] Fig. 10 shows a cross-sectional view of a rotor for an asynchronous motor according to a third embodiment. A rotor 100-3 according to the third embodiment differs from the rotor 100-1 according to the first embodiment in the following points. (1) The first protrusion portion 3b of the rotor 100-3 has a second protrusion portion 3b1 which is annular and arranged on the inner peripheral portion 3a1 of the first protrusion portion 3b. (2) The first groove portion 4b of the rotor 100-3 has a second groove portion 4b1 which is annular and arranged in an outer peripheral portion 4a-1 of the first groove portion 4b.

[0036] The width of the second projection portion 3b1 in the axial direction D1 is narrower than the width of the first projection portion 3b in the axial direction D1, and the width of the second groove portion 4b1 in the axial direction D1 is narrower than the width of the first groove portion 4b in the axial direction D1.

[0037] The end rings 3-1, 3-2 are formed by die-casting a conductive material. In this way, the first protrusion portion 3b and the first groove portion 4b are integrally formed, and the second protrusion portion 3b1 and the second groove portion 4b1 are integrally formed. The third embodiment has a structure in which the first protrusion portion 3b is fitted into the first groove portion 4b, and the second protrusion portion 3b1 is fitted into the second groove portion 4b1. This increases the contact area between the inner peripheral portions 3a of the end rings 3-1, 3-2 and the outer peripheral portions 4a of the reinforcement members 4-1, 4-2, making it larger than in the first embodiment, resulting in an increase in the frictional forces between the inner peripheral portions 3a of the end rings 3-1, 3-2 and the outer peripheral portions 4a of the reinforcement members 4-1, 4-2, making them larger than in the first embodiment.Furthermore, the first protrusion portion 3b is sandwiched in the first groove portion 4b, and the second protrusion portion 3b1 is sandwiched in the second groove portion 4b1. As a result, the degree of deformation of the end rings 3-1, 3-2 in the axial direction D1 and the radial direction D3 is smaller than in the first embodiment. Therefore, the third embodiment can further improve the fatigue resistance of the end rings 3-1, 3-2. Fourth embodiment

[0038] Fig. 11 shows a cross-sectional view of a rotor of an induction motor according to a fourth embodiment of the present invention. A rotor 100-4 according to the fourth embodiment differs from the rotor 100-1 according to the first embodiment in the following point. (1) In the outer peripheral portion 4a of each of the reinforcement members 4-1, 4-2 of the rotor 100-4, an outer diameter dimension OD1 of the outer peripheral portion 4a2 located on the rotor core 1 side of the first groove portion 4b is larger than an outer diameter dimension OD2 of an outer peripheral portion 4a3 located on the opposite side of the first groove portion 4b from the rotor core 1. The width of the outer peripheral portion 4a2 in the axial direction D1 corresponds to the width of the outer peripheral portion 4a3 in the axial direction D1.

[0039] In the rotor 100-1, the end rings 3-1, 3-2 deform upon thermal expansion and return to their original positions prior to thermal expansion due to thermal contraction. The thermal expansion and thermal contraction of the end ring 3-1 in the axial direction D1 are considered. The end ring 3-1 expands outward in the axial direction D1 during thermal expansion and contracts toward the rotor core 1 during thermal contraction in the axial direction D1. A force exerted by the end ring 3-1 on the reinforcement member 4-1 is also considered. When the end ring 3-1 undergoes thermal expansion and thermal contraction, stress also occurs between the reinforcement member 4-1 and the shaft 2, which are secured to each other by a shrink fit.

[0040] Of the two side walls formed by forming the first groove portion 4b in the reinforcement member 4-1 in the axial direction D1, the side wall located near the side opposite the rotor core 1 receives a force generated when the end ring 3-1 undergoes thermal expansion. In the rotor 100-4, since the outer diameter dimension OD2 is smaller than the outer diameter dimension OD1, a stress generated when the end ring 3-1 undergoes thermal expansion and thereby pushes the reinforcement member 4-1 outward in the axial direction D1 can be reduced. During thermal contraction, the side wall of the two side walls described above, which is located near the rotor core 1, is applied a force in the axial direction D1 toward the rotor core 1 side.Since the outer diameter dimension OD1 is larger than the outer diameter dimension OD2, a stress generated when the end ring 3-1 undergoes thermal contraction and thereby pushes the reinforcement member 4-1 back toward the rotor core 1 side may be increased. That is, during the thermal expansion of the end ring 3-1, a stress acts on the reinforcement member 4-1, thereby displacing the reinforcement member 4-1 from the position where the reinforcement member 4-1 was shrink-fitted to the shaft 2 toward the side opposite the rotor core 1. During the thermal contraction of the end ring 3-1, a stress acts on the reinforcement member 4-1, displacing the reinforcement member 4-1 from the position where the reinforcement member was shrink-fitted to the shaft 2 toward the rotor core 1.Since the reinforcement member 4-1 is significantly displaced from its above-described position toward the side opposite the rotor core 1 due to the large force applied during thermal expansion, the reinforcement member 4-1 is unlikely to return to its original position during thermal contraction, and the integrally formed end ring 3-1 is also likely to fail to return to its original shape. As a result, the end ring 3-1 is deformed, thereby shortening the service life of the rotor.

[0041] In the rotor 100-4 according to the fourth embodiment, the stress that occurs between the reinforcement member 4-1 and the shaft 2 during thermal contraction of the end ring 3-1 is greater than the stress that occurs between the reinforcement member 4-1 and the shaft 2 during thermal expansion of the end ring 3-1; this can prevent deformation of the reinforcement member 4-1 and the end ring 3-1. This also applies to the end ring 3-2 and the reinforcement member 4-2. Therefore, in the rotor 100-4, even if the positions of the reinforcement members 4-1, 4-2 are shifted in the axial direction D1 during thermal expansion, it can be assumed that the reinforcement members 4-1, 4-2 are retracted to their original positions before thermal expansion when the end rings 3-1, 3-2 undergo thermal contraction.

[0042] The fourth embodiment can be combined with any of the first to third embodiments. Fifth embodiment

[0043] Fig. 12 shows a cross-sectional view of a rotor of an induction motor according to a fifth embodiment of the present invention. A rotor 100-5 according to the fifth embodiment differs from the rotor 100-1 according to the first embodiment in the following point. (1) In the outer peripheral region 4a of each reinforcement member 4-1, 4-2 of the rotor 100-5, the outer diameter dimension OD2 of the outer peripheral region 4a3 located on the side of the first groove portion 4b opposite the rotor core 1 is larger than the outer diameter dimension OD1 of the outer peripheral region 4a2 located on the side of the first groove portion 4b adjacent to the rotor core 1. The width of the outer peripheral region 4a2 in the axial direction D1 corresponds to the width of the outer peripheral region 4a3 in the axial direction D1.

[0044] In the rotor 100-5, the outer diameter dimension OD2 is larger than the outer diameter dimension OD1; therefore, when centrifugal force acts on the end rings 3-1, 3-2, or when the end rings 3-1, 3-2 are subject to thermal expansion, the amount of deformation of the end rings 3-1, 3-2 in a direction opposite to the center of the rotor core 1 can be suppressed. This can further enhance the reinforcement effect on the end rings 3-1, 3-2. The fifth embodiment can be combined with any of the first to third embodiments. Sixth embodiment

[0045] In the sixth embodiment, first modifications of the first to fifth embodiments will be described. Fig. Figure 13 shows a diagram illustrating the first modification of the Fig. 2. A rotor in Fig. The rotor 100-6A illustrated in Figure 13 differs from that shown in Fig. 2 illustrated rotor 100-1 in the following points. (1) The first groove portions 4b of the rotor 100-6A each have a first inclined surface 4d at an end portion of each of the first groove portions 4b on the side opposite to the rotor core 1. (2) The first protrusion portions 3b of the rotor 100-6A each have a second inclined surface 3d at an end portion of each of the first protrusion portions 3b on the side opposite to the rotor core 1. The second inclined surface 3d is in contact with the first inclined surface 4d.

[0046] The first inclined surface 4d of the reinforcing element 4-1 has a shape that widens in the axial direction D1 from the reinforcing element 4-2 to the reinforcing element 4-1. The first inclined surface 4d of the reinforcing element 4-2 has a shape that widens in the axial direction D1 from the reinforcing element 4-1 to the reinforcing element 4-2. The second inclined surface 3d of the end ring 3-1 has a shape that widens in the axial direction D1 from the end ring 3-2 to the end ring 3-1. The second inclined surface 3d of the end ring 3-2 has a shape that widens in the axial direction D1 from the end ring 3-1 to the end ring 3-2.

[0047] Fig. 14 shows a diagram illustrating the first modification of the Fig. 9 illustrated rotor. A Fig. The rotor 100-6B illustrated in Figure 14 differs from that shown in Fig. 9 illustrate rotor 100-2 in the following points. (1) The first groove portions 4b of the rotor 100-6B each have a first inclined surface 4d at an end portion of each of the first groove portions 4b on the side opposite to the rotor core 1. (2) The first protrusion portions 3b of the rotor 100-6B each have a second inclined surface 3d at an end portion of each of the first protrusion portions 3b on the side opposite to the rotor core 1. The second inclined surface 3d is in contact with the first inclined surface 4d.

[0048] Fig. Figure 15 shows a diagram illustrating the first modification of the Fig. 10 illustrated rotor. A Fig. The rotor 100-6C illustrated in Figure 15 differs from the one shown in Fig. 10 illustrated rotor 100-3 in the following points. (1) The first groove portions 4b and the second groove portions 4b1 of the rotor 100-6C each have the first inclined surface 4d at an end portion of each of the first groove portions 4b and the second groove portions 4b1 on the side opposite to the rotor core 1. (2) The first protrusion portions 3b and the second protrusion portions 3b1 of the rotor 100-6C each have the second inclined surface 3d at an end portion of each of the first protrusion portions 3b and the second protrusion portions 3b1 on the side opposite to the rotor core 1. The second inclined surface 3d is in contact with the first inclined surface 4d.

[0049] Fig. 16 shows a diagram illustrating the first modification of the Fig. 11. A rotor shown in Fig. The rotor 100-6D illustrated in Figure 16 differs from the one shown in Fig. 11 illustrated rotor 100-4 in the following points. (1) The first groove portions 4b of the rotor 100-6D each have the first inclined surface at an end portion of each of the first groove portions 4b on the side opposite to the rotor core 1. (2) The first protrusion portions 3b of the rotor 100-6D each have the second inclined surface 3d at an end portion of each of the first protrusion portions 3b on the side opposite to the rotor core 1. The second inclined surface 3d is in contact with the first inclined surface 4d.

[0050] Fig. 17 shows a diagram illustrating the first modification of the Fig. 12 illustrated rotor. A Fig. The rotor 100-6E illustrated in Figure 17 differs from the one shown in Fig. 12 illustrated rotor 100-5 in the following points. (1) The first groove portions 4b of the rotor 100-6E each have the first inclined surface 4d at an end portion of each of the first groove portions 4b on the side opposite to the rotor core 1. (2) The first protrusion portions 3b of the rotor 100-6E each have the second inclined surface 3d at an end portion of each of the first protrusion portions 3b on the side opposite to the rotor core 1. The second inclined surface 3d is in contact with the first inclined surface 4d.

[0051] Deformation due to frictional forces between the inner peripheral portions 3a of the end rings 3-1, 3-2 and the outer peripheral portions 4a of the reinforcement elements 4-1, 4-2 during rotation can be better prevented if the surfaces are inclined relative to the central axis AX. To better prevent deformation during rotation, the contact area inclined relative to the central axis AX is preferably enlarged.

[0052] In the sixth embodiment, by forming the first inclined surface 4d in each of the first groove portions 4b and the second inclined surface 3D in each of the first projection portions 3b, the area of ​​the inclined surfaces relative to the central axis AX within the contact area between the inner peripheral portions 3a of the end rings 3-1, 3-2 and the outer peripheral portions 4a of the reinforcing members 4-1, 4-2 is increased to be larger than in the first to fifth embodiments, thereby increasing the frictional forces between the inner peripheral portions 3a of the end rings 3-1, 3-2 and the outer peripheral portions 4a of the reinforcing members 4-1, 4-2 to be larger than in the first to fifth embodiments. As a result, the reinforcing effect on the end rings 3-1, 3-2 can be further improved. Seventh embodiment

[0053] In a seventh embodiment, second modifications of the first to fifth embodiments will be described. Fig. 18 shows a diagram illustrating the second modification of the Fig. 2. A rotor in Fig. The rotor 100-7A illustrated in Figure 18 differs from that shown in Fig. 2 illustrated rotor 100-1 in the following points. (1) The first groove portions 4b of the rotor 100-7A each have a first inclined surface 4d1 at an end portion of each of the first groove portions 4b on the rotor core 1 side. (2) The first protrusion portions 3b of the rotor 100-7A each have a second inclined surface 3d1 at an end portion of each of the first protrusion portions 3b on the rotor core 1 side. The second inclined surface 3d1 is in contact with the first inclined surface 4d1.

[0054] The first inclined surface 4d1 of the reinforcing element 4-1 has a shape that widens in the axial direction D1 from the reinforcing element 4-1 to the reinforcing element 4-2. The first inclined surface 4d1 of the reinforcing element 4-2 has a shape that widens in the axial direction D1 from the reinforcing element 4-2 to the reinforcing element 4-1. The second inclined surface 3d1 of the end ring 3-1 has a shape that widens in the axial direction D1 from the end ring 3-1 to the end ring 3-2. The second inclined surface 3d1 of the end ring 3-2 has a shape that widens in the axial direction D1 from the end ring 3-2 to the end ring 3-1.

[0055] Fig. 19 shows a diagram illustrating the second modification of the Fig. 9 illustrated rotor. A Fig. The rotor 100-7B illustrated in Figure 19 differs from that shown in Fig. 9 illustrated rotor 100-2 in the following points. (1) The first groove portions 4b of the rotor 100-7B each have the first inclined surface 4d1 at an end portion of each of the first groove portions 4b on the rotor core 1 side. (2) The first protrusion portions 3b of the rotor 100-7B each have the second inclined surface 3d1 at an end portion of each of the first protrusion portions 3b on the rotor core 1 side. The second inclined surface 3d1 is in contact with the first inclined surface 4d1.

[0056] Fig. 20 shows a diagram illustrating the second modification of the Fig. 10 illustrated rotor. A Fig. The rotor 100-7C illustrated in Figure 20 differs from the one shown in Fig. 10 illustrated rotor 100-3 in the following points. (1) The first groove portions 4b and the second groove portions 4b1 of the rotor 100-7C each have the first inclined surface 4d1 at an end portion of each of the first groove portion 4b and the second groove portion 4b1 on the rotor core 1 side. (2) The first protrusion portions 3b and the second protrusion portions 3b1 of the rotor 100-7C each have the second inclined surface 3d1 at an end portion of each of the first protrusion portions 3b and the second protrusion portions 3b1 on the rotor core 1 side. The second inclined surface 3d1 is in contact with the first inclined surface 4d1.

[0057] Fig. Figure 21 shows a diagram illustrating the second modification of the Fig. 11. A rotor shown in Fig. The rotor 100-7D illustrated in Figure 21 differs from the one shown in Fig. 11 illustrated rotor 100-4 in the following points. (1) The first groove portions 4b of the rotor 100-7D each have the first inclined surface 4d1 at an end portion of each of the first groove portions 4b on the rotor core 1 side. (2) The first protrusion portions 3b of the rotor 100-7D each have the second inclined surface 3d1 at an end portion of each of the first protrusion portions 3b on the rotor core 1 side. The second inclined surface 3d1 is in contact with the first inclined surface 4d1.

[0058] Fig. 22 shows a diagram illustrating the second modification of the Fig. 12 illustrated rotor. A Fig. The rotor 100-7E illustrated in Figure 22 differs from the one shown in Fig. 12 illustrated rotor 100-5 in the following points. (1) The first groove portions 4b of the rotor 100-7E each have the first inclined surface 4d1 at an end portion of each of the first groove portions 4b on the rotor core 1 side. (2) The first protrusion portions 3b of the rotor 100-7E each have the second inclined surface 3d1 at an end portion of each of the first protrusion portions 3b on the rotor core 1 side. The second inclined surface 3d1 is in contact with the first inclined surface 4d1.

[0059] In the seventh embodiment, by forming the first inclined surface 4d1 in each of the first groove portions 4b and the second inclined surface 3d1 in each of the first protrusion portions 3b, the contact area between the inner peripheral portions 3a of the end rings 3-1, 3-2 and the outer peripheral portions 4a of the reinforcing members 4-1, 4-2 is increased to be larger than in the first to fifth embodiments, thereby increasing the frictional forces between the inner peripheral portions 3a of the end rings 3-1, 3-2 and the outer peripheral portions 4a of the reinforcing members 4-1, 4-2 to be larger than in the first to fifth embodiments. As a result, the reinforcing effect on the end rings 3-1, 3-2 can be further improved. Eighth embodiment

[0060] In an eighth embodiment, third modifications of the first to fifth embodiments will be described. Fig. Figure 23 shows a diagram illustrating the third modification of the Fig. 2. In a Fig. In the rotor 100-8A illustrated in FIG. 23, the first groove portions 4b each have the first inclined surface 4d of the sixth embodiment and the first inclined surface 4d1 of the seventh embodiment. Furthermore, in the rotor 100-8A, the first protrusion portions 3b each have the second inclined surface 3d of the sixth embodiment and the second inclined surface 3d1 of the seventh embodiment.

[0061] Fig. Figure 24 is a diagram illustrating the third modification of the Fig. 9. In a Fig. In the rotor 100-8B illustrated in FIG. 24, the first groove portions 4b each have the first inclined surface 4d of the sixth embodiment and the first inclined surface 4d1 of the seventh embodiment. Furthermore, the first protrusion portions 3b in the rotor 100-8B each have the second inclined surface 3d of the sixth embodiment and the second inclined surface 3d1 of the seventh embodiment.

[0062] Fig. Figure 25 shows a diagram illustrating the third modification of the Fig. 10. In a Fig. In the rotor 100-8C illustrated in FIG. 25, the first groove portions 4b and the second groove portions 4b1 each have the first inclined surface 4d of the sixth embodiment and the first inclined surface 4d1 of the seventh embodiment. Furthermore, the first protrusion portions 3b and the second protrusion portions 3b1 in the rotor 100-8C each have the second inclined surface 3d of the sixth embodiment and the second inclined surface 3d1 of the seventh embodiment.

[0063] Fig. 26 shows a diagram illustrating the third modification of the Fig. 11. In a rotor shown in Fig. In the rotor 100-8D illustrated in FIG. 26, the first groove portions 4b each have the first inclined surface 4d of the sixth embodiment and the first inclined surface 4d1 of the seventh embodiment. Furthermore, the first protrusion portions 3b in the rotor 100-8D each have the second inclined surface 3d of the sixth embodiment and the second inclined surface 3d1 of the seventh embodiment.

[0064] Fig. Figure 27 shows a diagram illustrating the third modification of the Fig. 12. In a Fig. In the rotor 100-8E illustrated in FIG. 27, the first groove portions 4b each have the first inclined surface 4d of the sixth embodiment and the first inclined surface 4d1 of the seventh embodiment. Furthermore, the first protrusion portions 3b in the rotor 100-8E each have the second inclined surface 3d of the sixth embodiment and the second inclined surface 3d1 of the seventh embodiment.

[0065] In the eighth embodiment, by forming the first inclined surface 4d and the first inclined surface 4d1 in each of the first groove portions 4b and forming the second inclined surface 3d and the second inclined surface 3d1 in each of the first projection portions 3b, the contact area between the inner peripheral portions 3a of the end rings 3-1, 3-2 and the outer peripheral portions 4a of the reinforcing members 4-1, 4-2 is increased to be larger than in the first to fifth embodiments, thereby increasing the frictional forces between the inner peripheral portions 3a of the end rings 3-1, 3-2 and the outer peripheral portions 4a of the reinforcing members 4-1, 4-2 to be larger than in the first to fifth embodiments. As a result, the reinforcing effect on the end rings 3-1, 3-2 can be further improved.

[0066] In the first to eighth embodiments, the reinforcing elements have groove regions, wherein the groove regions can be formed in the manner described below. Fig. Figure 28 is a diagram illustrating a fourth modification of the Fig. 2. A rotor in Fig. The rotor 100-9 illustrated in Figure 28 has reinforcement elements 4-1B, 4-2B instead of reinforcement elements 4-1, 4-2 and end rings 3-1B, 3-2B instead of end rings 3-1, 3-2.

[0067] The reinforcement element 4-1B has a first annular region 41, which is arranged in the reinforcement element 4-1B near the side opposite the rotor core 1, and a second annular region 42, which is arranged in the reinforcement element 4-1B near the rotor core 1. The outer diameter of the second annular region 42 is smaller than the outer diameter of the first annular region 41. As a result, a stepped region is formed between the first annular region 41 and the second annular region 42. The reinforcement element 4-2B is constructed similarly to the reinforcement element 4-1B.

[0068] The inner peripheral portion 3a of the end ring 3-1B, which is formed by die casting, is in contact with the outer peripheral portions 4a of the first annular portion 41 and the second annular portion 42. An end portion 3e of the first protrusion portion 3b on the side opposite the rotor core 1 is in contact with an end portion 4e of the first annular portion 41 on the side toward the rotor core 1, which means that the end portion 3e is in contact with the step portion between the first annular portion 41 and the second annular portion 42. This means that the first protrusion portion 3b is fitted to the step portion. As a result, in the end ring 3-1B, the first protrusion portion 3b is retained by the step portion during rotation, which can prevent deformation of the end ring 3-1B during rotation. A similar effect is obtained in the end ring 3-2B during rotation.

[0069] If the outer diameter of the second annular region 42 is larger than the outer diameter of the first annular region 41, the contact area is reduced compared to the Fig. 7; however, the first projection portion 3b of the end ring 3-1B is not retained at the above-described step portion during rotation, and deformation during rotation cannot be sufficiently prevented.

[0070] It should be noted that the configurations described in the foregoing embodiments are examples of the subject matter of the present invention; combining the present invention with other publicly known techniques is possible, and omission of parts and modification of the configurations are possible without departing from the gist of the present invention. List of reference symbols 1 rotor core; 1a, 4c through hole; 1b1, 6a one end area; 1b2, 6b the other end area; 2nd wave; 3-1, 3-1A, 3-1B, 3-2, 3-2A, 3-2B end ring; 3a, 3a1 inner peripheral area; 3b first projection area; 3b1 second projection area; 3c end area; 3d, 3d1 second inclined surface; 3e, 4e end area; 4-1, 4-1A, 4-1B, 4-2, 4-2A, 4-2B reinforcement element; 4a, 4a1, 4a2, 4a3 outer peripheral area; 4b first groove area; 4b1 second groove area; 4d, 4d1 first inclined surface; 5 core groove; 6 ladder rod; 41 first annular area; 42 second annular area; 100-1, 100-2, 100-7B, 100-7C, 100-3, 100-4, 100-5, 100-6A, 100-6B, 100-6C, 100-6D, 100-6E, 100-7A, 100-7D, 100-7E, 100-8A, 100-8B, 100-8C, 100-8D, 100-8E, 100-9, 100A rotor; 300 asynchronous motor; 200 stator; 210 housings; 220 stator core; 230 winding; AX central axis; D1 axis line direction; D2 axis line circumferential direction; D3 radial direction; OD1, OD2 outside diameter dimension.

Claims

[1] Rotor (100-4; 100-6D; 100-7D; 100-8D) for an asynchronous motor, the rotor comprising: a rotor core (1), a shaft (2) which is guided through the rotor core (1), an annular end ring (3-1, 3-2) arranged in an end region of the rotor core (1), and an annular reinforcing element (4-1, 4-2) arranged between the shaft (2) and an inner peripheral portion (3a) of the end ring (3-1, 3-2) and comprising an outer peripheral portion (4a) in contact with the end ring (3-1, 3-2), wherein a first projection portion (3b) arranged on the inner peripheral portion (3a) of the end ring (3-1, 3-2) is fitted into a first groove portion (4b) arranged in the outer peripheral portion (4a) of the reinforcing element (4-1, 4-2), characterized by , that in the outer peripheral region (4a) of the reinforcing element (4-1, 4-2), an outer diameter dimension (OD1) of an outer peripheral region (4a2) on one side of the rotor core (1) with respect to the first groove region (4b) is larger than an outer diameter dimension (OD2) of an outer peripheral region (4a3) on a side opposite the rotor core (1) with respect to the first groove region (4b). [2] Rotor (100-5; 100-6E; 100-7E; 100-8E) for an asynchronous motor, the rotor comprising: a rotor core (1), a shaft (2) which is guided through the rotor core (1), an annular end ring (3-1, 3-2) arranged at an end portion of the rotor core (1), and an annular reinforcing element (4-1, 4-2) arranged between the shaft (2) and an inner peripheral portion (3a) of the end ring (3-1, 3-2) and having an outer peripheral portion (4a) in contact with the end ring (3-1, 3-2), wherein a first projection portion (3b) arranged on the inner peripheral portion (3a) of the end ring (3-1, 3-2) is fitted into a first groove portion (4b) arranged in the outer peripheral portion (4a) of the reinforcing element (4-1, 4-2), characterized by , that in the outer peripheral region (4a) of the reinforcing element (4-1, 4-2), an outer diameter dimension (OD2) of an outer peripheral region (4a3) on a side opposite the rotor core (1) with respect to the first groove region (4b) is larger than an outer diameter dimension (OD1) of an outer peripheral region (4a2) on a side of the rotor core (1) with respect to the first groove region (4b). [3] Rotor (100-4; 100-5) for an asynchronous motor according to claim 1 or 2, wherein the first projection portion (3b) and the first groove portion (4b) are annular. [4] Rotor for an asynchronous motor according to one of claims 1 to 3, wherein the end ring (3-1, 3-2) has a second projection portion (3b1) arranged in an inner peripheral portion (3a1) of the first projection portion (3b), the reinforcing element (4-1, 4-2) has a second groove portion (4b1) which is arranged in an outer peripheral portion (4a1) of the first groove portion (4b) and into which the second projection portion (3b1) is fitted, a width of the second projection portion (3b1) in an axial line direction (D1) of a central axis (AX) of the rotor core (1) is narrower than a width of the first projection portion (3b) in the axial line direction (D1) and a width of the second groove region (4b1) in the axial line direction (D1) is narrower than a width of the first groove region (4b) in the axial line direction (D1). [5] Rotor (100-6D; 100-6E; 100-7D; 100-7E; 100-8D; 100-8E) for an asynchronous motor according to one of claims 1 to 4, wherein the first groove portion (4b) has a first inclined surface (4d, 4d1) at an end portion of the first groove portion (4b) in the axial line direction (D1) of the central axis (AX) of the rotor core (1) and the first projection portion (3b) has a second inclined surface (3d, 3d1) at an end portion of the first projection portion (3b) in the axial line direction (D1), the second inclined surface (3d, 3d1) being in contact with the first inclined surface (4d, 4d1). [6] Asynchronous motor (300) comprising a rotor (100-4; 100-5; 100-6D; 100-6E; 100-7D; 100-7E; 100-8D; 100-8E) for an asynchronous motor according to one of claims 1 to 5.

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