Rotor

Abstract

To provide a rotor that prevents a damage of a sleeve of an outer diameter side for preventing a permanent magnet form peeling.SOLUTION: A rotor for a rotary electric machine of the present invention comprises: a cylindrical sleeve; a plurality of permanent magnets arranged in a peripheral direction while being adhered to an inner peripheral surface of the cylindrical sleeve; and a shaft arranged to an inner diameter side of each permanent magnet. Then, each permanent magnet includes a flat surface in the inner diameter side in a view of a shaft direction, and an outer diameter side is a fan shape along the inner peripheral surface of the cylindrical sleeve, and the shaft is a regular polygon where the number of permanent magnets and angles are the same when viewed in the shaft direction, and a flat surface of the inner diameter side of each permanent magnet and a side surface of the shaft are oppositely arranged. A spacer is provided between each permanent magnet and the shaft is provided, and a damage of the sleeve on the outer diameter side is prevented.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a rotor, and more particularly to a rotor used in a surface magnet type rotating electric machine. [Background technology]

[0002] Surface magnet rotors, in which permanent magnets are attached to the surface, can efficiently utilize the magnetic properties of the permanent magnets, but they have the problem that the adhesion of the permanent magnets is weak. Therefore, for rotors that require particularly high speed rotation, the permanent magnets are reinforced by covering them with a cylindrical sleeve so that they can withstand centrifugal force.

[0003] Patent document 1 discloses a rotor in which a permanent magnet is sandwiched between a double-structure cylindrical sleeve, and describes how by forming a gap between the inner diameter sleeve and the permanent magnet that becomes larger toward the circumferential edge of the permanent magnet, it is possible to prevent the permanent magnet from cracking due to the inner diameter sleeve expanding when a shaft is pressed into the inner diameter sleeve. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2016-096641 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the rotor described in Patent Document 1, permanent magnets are arranged on the outer peripheral surface of the inner diameter sleeve, and the permanent magnets are arranged based on the inner diameter sleeve. Therefore, if the permanent magnets have a dimensional error, a step will occur between the permanent magnets and their adjacent permanent magnets on the outer diameter side.

[0006] Furthermore, when the permanent magnets are subjected to a load in the outer diameter direction due to rotation of the rotor, the steps between the permanent magnets will bite into the outer diameter sleeve, causing stress to concentrate, which may damage the outer diameter sleeve that prevents the permanent magnets from peeling off.

[0007] The present invention has been made in consideration of the problems associated with the prior art, and has as its object to provide a rotor that prevents damage to the outer diameter side sleeve that prevents the permanent magnets from peeling off. [Means for solving the problem]

[0008] As a result of extensive research into achieving the above-mentioned object, the inventors discovered that the above-mentioned object could be achieved by using a cylindrical sleeve on the outer diameter side that covers the permanent magnet as a reference, adhering the permanent magnet to the inner surface of the cylindrical sleeve, and providing a spacer between the permanent magnet and the shaft to adjust the dimensional error of the permanent magnet, thereby completing the present invention.

[0009] That is, the rotary electric rotor of the present invention comprises a cylindrical sleeve; A plurality of permanent magnets arranged in a circumferential direction and bonded to an inner peripheral surface of the cylindrical sleeve; and a shaft disposed on the inner diameter side of the permanent magnet. The permanent magnet, when viewed in the axial direction, has a flat surface on its inner diameter side and its outer diameter side is sector-shaped along the inner circumferential surface of the cylindrical sleeve, the shaft, when viewed in the axial direction, is a regular polygon with the same number of angles as the number of permanent magnets, the inner diameter side flat surface of the permanent magnet and the side surface of the shaft are arranged opposite each other, and a spacer is provided between the permanent magnet and the shaft. Effect of the Invention

[0010] According to the present invention, a permanent magnet is bonded to the inner surface of a cylindrical sleeve and dimensional errors of the permanent magnet are absorbed between the permanent magnet and the shaft, thereby providing a rotor in which no step occurs on the outer diameter side of the permanent magnet and which can prevent damage to the cylindrical sleeve. [Brief description of the drawings]

[0011] [Figure 1] 1 is a cross-sectional view showing an example of a rotor as viewed from an axial direction. [Diagram 2] 1 is a diagram illustrating a conventional rotor in which steps are generated on the outer diameter side surface between permanent magnets. [Diagram 3] FIG. 4 is a perspective view showing an example of a shape of a spacer. [Figure 4] 13 is a diagram illustrating a state in which a spacer supports a permanent magnet from the inner diameter side. FIG. [Diagram 5] 11A and 11B are diagrams illustrating a state in which a permanent magnet is tilted. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] The rotor of the present invention will now be described in detail. As shown in FIG. 1, the rotor of the present invention is a rotor for a surface permanent magnet (SPM) rotating electric machine, which comprises a shaft 3 and a plurality of permanent magnets 2 arranged circumferentially on the outer diameter side of the shaft, and further comprises a cylindrical sleeve 1 made of CFRP arranged on the outer diameter side of the permanent magnets 2.

[0013] The cylindrical sleeve 1 resists the centrifugal force caused by the rotation of the rotor and supports the load acting on the permanent magnet in the radial direction, thereby preventing the permanent magnet 2 from peeling off.

[0014] In the above-described surface magnet type rotating electric machine, by arranging the permanent magnets 2 in a Halbach array, the magnetic field can be concentrated on one side, strengthening the magnetic force and improving the magnetic efficiency.

[0015] The Halbach array is an array in which radially magnetized permanent magnets 2a and circumferentially magnetized permanent magnets 2b are arranged in the circumferential direction, and is formed by connecting multiple permanent magnets with different magnetization directions.

[0016] Furthermore, since dimensional errors inevitably occur in each permanent magnet 2, if the permanent magnets 2 are arranged on the outer peripheral surface of the shaft 3 based on the inner diameter side of the shaft 3, a step due to the above-mentioned dimensional errors will occur on the outer diameter side surface between adjacent permanent magnets, as shown in the circled area in Figure 2.

[0017] If the rotor rotates at high speed with this step occurring, the cylindrical sleeve 1 supporting the permanent magnet from the outer diameter side may be subjected to localized stress from the step and may be damaged.

[0018] The rotor of the present invention overcomes the above-mentioned inconveniences caused by dimensional errors that inevitably occur in permanent magnets.

[0019] The rotor of the present invention is manufactured by using a cylindrical sleeve 1 on the outer diameter side as a reference, applying a uniform thickness of adhesive to the inner surface of the cylindrical sleeve 1, adhering and fixing a permanent magnet 2, placing a spacer 5 on the inner diameter side of the permanent magnet, pressing in a shaft 3, and then fixing them together with an adhesive.

[0020] As shown in FIG. 1, when viewed in the axial direction, the permanent magnet 2 has a flat surface on its inner diameter side and a sector shape on its outer diameter side that conforms to the inner circumferential surface of the cylindrical sleeve. Also, when viewed in the axial direction, the shaft 3 is a regular polygon with the same number of angles as the permanent magnets.

[0021] The permanent magnet 2 and shaft 3 are arranged so that the inner diameter side flat surface of the permanent magnet faces the side surface of the shaft, and a spacer 5 having a flat plate portion 51 is provided between them.

[0022] Furthermore, if the permanent magnet 2 is manufactured so that its outer dimensions are within the allowable tolerance and are not larger than the design dimensions, even if the permanent magnet 2 is pressed toward the outer diameter by pressing the shaft 3 into it, the permanent magnet will not expand toward the outer diameter beyond the design dimensions.

[0023] In addition, since the dimensional errors of the permanent magnets can be absorbed by the thickness of the spacer and adhesive provided on the inner diameter side of the permanent magnets, no step occurs between the outer diameter side of the permanent magnets and adjacent permanent magnets.

[0024] Therefore, no localized stress is applied to the cylindrical sleeve 1, which supports the load received by the permanent magnet 2 from the outer diameter direction, and the load received by the permanent magnet 2 is applied evenly to the inner surface of the cylindrical sleeve 1, thereby preventing damage to the cylindrical sleeve 1.

[0025] As shown in FIG. 3, the spacer preferably has a shape including a flat plate portion 51 and wedge portions 52 on both ends thereof when viewed in the axial direction.

[0026] As shown in FIG. 4, this spacer is arranged between the side surface of the shaft and the inner diameter flat surface of the permanent magnet, with its flat portion 51 facing the side surface of the shaft and the inner diameter flat surface of the permanent magnet, with the wedge portion wedging into the space between the permanent magnets and its blade surface abutting the inner diameter side end portion of the permanent magnet.

[0027] When the shaft is pressed into the spacer of the above shape, the wedge portions enter between the permanent magnets and expand the space between adjacent permanent magnets, so that the spacer can absorb not only radial dimensional errors of the permanent magnets but also circumferential dimensional errors.

[0028] In this state, by fixing the permanent magnets and the spacer, and the permanent magnets themselves, with adhesive, the permanent magnets will not shift even if stress is applied to them, and steps caused by tilting the permanent magnets can also be prevented.

[0029] In other words, as the rotor rotates, the permanent magnet 2 is subjected to stress that tilts the permanent magnet in the direction in which it rotates, as shown by the arrow in Figure 5, due to changes in the magnetic field it receives from the stator. This tilt of the permanent magnet 2 can also cause steps to form on the outer diameter side between adjacent permanent magnets.

[0030] Since the blade surface of the wedge portion of the spacer abuts against the inner diameter side end of the permanent magnet, tilting of the permanent magnet due to rotation of the rotor can be prevented, and damage to the cylindrical sleeve can be prevented.

[0031] The spacer can be made of any non-magnetic material, but is preferably made of an elastic material such as resin or rubber.

[0032] The shape of the blade surface of the wedge portion may be flat or stepped, depending on the material from which the wedge portion is made.

[0033] If the wedge portion is formed from a material that is easily elastically deformed, the edge of the flat end portion on the inner diameter side of the permanent magnet will bite into the wedge portion, securely supporting the permanent magnet from the inner diameter side, and since the blade surface is formed flat, it is possible to absorb dimensional errors of the permanent magnet in a stepless manner.

[0034] Furthermore, in cases where the wedge portion is difficult to elastically deform and the edge of the permanent magnet is difficult to bite into the wedge portion, the blade surface can be made stepped to stably support the permanent magnet from the inner diameter side.

[0035] The spacer may be a plurality of divided members, the number of which is equal to the number of the permanent magnets, but is preferably a continuous annular part. By making the spacer a single part, the number of parts can be reduced, thereby reducing the number of manufacturing steps. [Explanation of symbols]

[0036] 1 Cylindrical sleeve 2a permanent magnet 2b Permanent magnet 3 Shaft 4 Adhesive layer 5 Spacer 51 Flat plate part 52 Wedge part

Claims

1. a cylindrical sleeve; a plurality of permanent magnets bonded to the inner peripheral surface of the cylindrical sleeve and arranged in a circumferential direction; a shaft disposed on an inner diameter side of the permanent magnet, When viewed in the axial direction, the permanent magnet has a flat surface on its inner diameter side and a sector shape on its outer diameter side that conforms to the inner circumferential surface of the cylindrical sleeve, the shaft is a regular polygon with the same number of angles as the number of the permanent magnets when viewed in the axial direction, The inner diameter side flat surface of the permanent magnet and the side surface of the shaft are arranged to face each other, The rotor further comprises a spacer between the permanent magnet and the shaft.

2. The spacer has a shape including a flat plate portion and wedge portions at both ends thereof when viewed in the axial direction, the flat portion of the spacer is disposed between a side surface of the shaft and an inner diameter side flat surface of the permanent magnet, 2. The rotor according to claim 1, wherein the flat portion faces the side surface of the shaft, the wedge portion is inserted between the permanent magnets, and the blade surface abuts against the inner diameter side end of the permanent magnet.

3. 3. The rotor according to claim 2, wherein the spacer is made of an elastic material.

4. 4. The rotor according to claim 3, wherein the blade surfaces of the wedge portions are flat.

5. 4. The rotor according to claim 3, wherein the blade surfaces of the wedge portions are stepped.

6. 3. The rotor according to claim 2, wherein the spacer is a single continuous annular piece.

7. 4. The rotor according to claim 3, wherein the permanent magnets and the spacers, and the permanent magnets themselves, are fixed with an adhesive.

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