Rotor and motor

Abstract

To provide a rotor and motor that can suppress deformation of the end plate during assembly.SOLUTION: A rotor 1 includes a shaft 2 extending along a central axis C, a rotor core 3 disposed radially outward of the shaft 2 and extending along the axial direction, and end plates 4 disposed at both axial ends of the rotor core 3, expanding radially, and contacting the shaft 2 at their radially inner edges. The end plates 4 have a first surface axially facing the rotor core 3, a second surface axially facing the opposite side from the first surface, and a recess adjacent to the shaft 2 at its radially inner edge and recessed axially from the first surface or the second surface.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a rotor and a motor. [Background technology]

[0002] Conventionally, rotors have been known that have end plates disposed at both axial ends of a rotor core. The end plates are formed in an annular plate shape. A shaft extending along the central axis of the rotor is fitted through the radial center of the end plate (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2012-205402 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the conventional technology, when the end plate and the shaft are joined by press-fitting, there is a problem in that the end plate may be deformed due to stress generated in the end plate.

[0005] In view of the above, an object of the present disclosure is to provide a rotor and a motor that can suppress deformation of end plates during assembly. [Means for solving the problem]

[0006] An exemplary rotor according to the present disclosure includes a shaft extending along a central axis, a rotor core disposed radially outward of the shaft and extending axially, and end plates disposed at both axial ends of the rotor core, extending radially, and contacting the shaft at their radially inner edges. The end plates each have a first surface axially facing the rotor core, a second surface axially facing the opposite side from the first surface, and a recess adjacent to the shaft at its radially inner edge and recessed axially from the first surface or the second surface.

[0007] An exemplary motor according to the present disclosure includes a rotor having the above-described configuration and a stator disposed radially opposite the rotor. [Effects of the Invention]

[0008] According to the exemplary rotor and motor of the present disclosure, the recesses facilitate the radially outward propagation of stress that occurs when joining the end plate and the shaft by press-fitting, thereby preventing stress from concentrating at the joining points between the end plate and the shaft and suppressing deformation of the end plate. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a longitudinal cross-sectional view of a motor according to an embodiment of the present disclosure. [Figure 2] FIG. 2 is a perspective view of a longitudinal section of the rotor. [Figure 3] FIG. 3 is a vertical cross-sectional view of the end plate. [Figure 4] FIG. 4 is a perspective view of a vertical cross section of the end plate. [Figure 5] FIG. 5 is a vertical cross-sectional view of an end plate according to the first modification. [Figure 6] FIG. 6 is a perspective view of a vertical cross section of an end plate of the first modified example. [Figure 7] FIG. 7 is a graph showing the relationship between the interference and stress of the end plate. [Figure 8]FIG. 8 is a vertical cross-sectional view of an end plate according to the second modification. [Figure 9] FIG. 9 is a perspective view of a vertical cross section of an end plate of the second modification. [Figure 10] FIG. 10 is a vertical cross-sectional view of an end plate according to the third modification. [Figure 11] FIG. 11 is a perspective view of a vertical cross section of an end plate according to the third modification. [Figure 12] FIG. 12 is a vertical cross-sectional view of an end plate according to the fourth modification. [Figure 13] FIG. 13 is a perspective view of a vertical cross section of an end plate according to the fourth modification. [Figure 14] FIG. 14 is a vertical cross-sectional view of an end plate according to the fifth modification. [Figure 15] FIG. 15 is a perspective view of a vertical cross section of an end plate according to the fifth modification. DETAILED DESCRIPTION OF THE INVENTION

[0010] A motor according to an exemplary embodiment of the present disclosure will be described below with reference to the drawings. Note that the scope of the present disclosure is not limited to the following embodiment and can be modified as desired within the scope of the technical concept of the present disclosure.

[0011] In this document, the direction parallel to the motor's central axis is simply referred to as the "axial direction," the direction perpendicular to the motor's central axis is simply referred to as the "radial direction," and the direction along a circle centered on the motor's central axis is simply referred to as the "circumferential direction." For ease of explanation, this document will refer to the motor's central axis as extending in the vertical direction. Therefore, the shape and positional relationship of each part will be described assuming that the axial direction is the "vertical direction" and that the vertical direction in Figure 1 is the vertical direction of the motor. This definition of the vertical direction does not limit the orientation or positional relationship of the motor when in use.

[0012] In this specification, a cross section parallel to the axial direction is referred to as a “longitudinal cross section.” In addition, the terms “parallel” and “orthogonal” used in this specification do not mean parallel or orthogonal in the strict sense, but also include substantially parallel and substantially orthogonal.

[0013] <1. Motor Overview> Fig. 1 is a longitudinal cross-sectional view of a motor 100 according to one embodiment. The motor 100 includes a rotor 1 and a stator 11. Fig. 2 is a longitudinal cross-sectional perspective view of the rotor 1.

[0014] The rotor 1 is disposed radially inside the stator 11. The rotor 1 includes a shaft 2, a rotor core 3, and end plates 4.

[0015] The shaft 2 is disposed along a central axis C that extends in the vertical direction. The shaft 2 extends along the central axis C. The shaft 2 is a columnar member that is made of, for example, metal and extends in the vertical direction.

[0016] The rotor core 3 is disposed radially outward of the shaft 2. The rotor core 3 extends along the axial direction. The rotor core 3 is cylindrical and fixed to the radially outer periphery of the shaft 2, which is inserted radially inward. The rotor core 3 is formed, for example, by stacking multiple electromagnetic steel plates in the vertical direction.

[0017] The rotor core 3 has a magnet (not shown). The magnet is fixed, for example, to the radially outer periphery of the rotor core 3. The magnet has south poles and north poles arranged alternately in the circumferential direction.

[0018] The end plates 4 are arranged at both axial ends of the rotor core 3. The end plates 4 include an end plate 4A arranged at the axial upper end of the rotor core 3 and an end plate 4B arranged at the axial lower end of the rotor core 3. The end plates 4 are formed in the shape of annular plates extending in the radial direction.

[0019] The end plate 4 has a through hole 4h in the radial center. The through hole 4h passes through the end plate 4 in the axial direction. The shaft 2 is inserted into the through hole 4h. The end plate 4 contacts the shaft 2 at its radial inner edge. More specifically, the end plate 4 contacts the shaft 2 at the cylindrical surface of the radial inner edge. The end plate 4 is joined by press-fitting the shaft 2 into the through hole 4h.

[0020] The stator 11 is disposed radially outside the rotor 1. The stator 11 is disposed radially opposite the rotor 1. The stator 11 includes a stator core 12 and a coil 13.

[0021] The stator core 12 has a core back portion 12b and a plurality of teeth 12t. The core back portion 12b is annular about a central axis C. The plurality of teeth 12t extend radially inward from the radial inner circumferential surface of the core back portion 12b toward the central axis C. The plurality of teeth 12t are arranged at predetermined intervals in the circumferential direction. The stator core 12 is formed, for example, by stacking a plurality of electromagnetic steel plates in the vertical direction.

[0022] The coil 13 is formed of a conductive wire wound around an insulator (not shown) for each of the multiple teeth 12t. That is, the insulator is interposed between the teeth 12t and the coil 13. The teeth 12t and the coil 13 are electrically insulated from each other by the insulator. The multiple coils 13 are arranged at predetermined intervals in the circumferential direction.

[0023] In the motor 100 configured as described above, when a drive current is supplied to the coil 13, a radial magnetic flux is generated in the stator core 12. The magnetic field generated by the magnetic flux of the stator 11 interacts with the magnetic field generated by the magnet of the rotor 1, generating a torque in the circumferential direction of the rotor 1. This torque causes the rotor 1 to rotate about the central axis C.

[0024] <2. Detailed configuration of end plate> Next, a detailed description will be given of the configuration of the end plate 4. Fig. 3 is a vertical cross-sectional view of the end plate 4B. Fig. 4 is a vertical cross-sectional perspective view of the end plate 4B as viewed from above in the axial direction.

[0025] In this embodiment, the end plate 4B on the axially lower end side of the rotor core 3 will be described as an example, but the end plate 4A on the axially upper end side of the rotor core 3 may also have a similar configuration. Therefore, in the following description, the identification symbols "A" and "B" may be omitted unless otherwise specified.

[0026] The end plate 4B has a first surface 41, a second surface 42, a recess 43, and a corner 44.

[0027] The first surface 41 faces the rotor core 3 in the axial direction. In the end plate 4B of the present embodiment, the first surface 41 faces axially upward. The first surface 41 faces and is adjacent to the axial lower surface of the rotor core 3.

[0028] The second surface 42 faces in the axial direction opposite to the first surface 41. In the end plate 4B of this embodiment, the second surface 42 faces downward in the axial direction.

[0029] The recess 43 is adjacent to the shaft 2 at the radial inner edge of the end plate 4. The recess 43 is recessed in the axial direction from the first surface 41 or the second surface 42. In the end plate 4B of this embodiment, the recess 43 is recessed axially downward from the first surface 41, which is the axial upper surface of the end plate 4B.

[0030] According to the above configuration, the thickness of the end plate 4 is reduced at the recess 43. This makes it possible to easily propagate stress generated when the shaft 2 is press-fitted into the end plate 4 radially outward without being confined to the radially inner edge of the end plate 4. In other words, it is possible to prevent stress from concentrating at the joint between the end plate 4 and the shaft 2, and to suppress deformation of the end plate 4.

[0031] The recess 43 is located on one axial side of the axial center Cx of the end plate 4. In the end plate 4B of this embodiment, the recess 43 is located axially above the axial center Cx of the end plate 4B. This configuration prevents the thickness of the end plate 4 from being significantly reduced at the recess 43. This makes it possible to prevent deformation of the end plate 4.

[0032] The recess 43 has a bottom portion with an inclined surface 431. In other words, the bottom surface of the recess 43 is configured with the inclined surface 431. More specifically, in the end plate 4B of this embodiment, the recess 43 has the inclined surface 431 that gradually inclines away from the first surface 41 downward in the axial direction as it approaches the central axis C along the radial direction.

[0033] The inclined surface 431 is disposed in a region inside the intermediate Cr1 extending from the radial inner edge to the radial outer edge of the end plate 4. With respect to this intermediate Cr1, the radial length L1 from the radial inner edge of the end plate 4 to the intermediate Cr1 is the same as the radial length L1 from the radial outer edge of the end plate 4 to the intermediate Cr1.

[0034] According to the above configuration, the inclined surface 431 facilitates the propagation of stress radially outward. Furthermore, by forming the inclined surface 431 in a region inside the radial middle Cr1 of the end plate 4, it is possible to ensure a thick region of the end plate 4 over a wide range. This ensures the strength of the end plate 4 and makes it possible to suppress deformation of the end plate 4.

[0035] In this embodiment, the inclined surface 431 is formed in a region inside the intermediate portion Cr1 from the radial inner edge to the outer edge of the end plate 4, but the step 451 described below may also be formed in a region inside the intermediate portion Cr1 from the radial inner edge to the outer edge of the end plate 4.

[0036] The corners 44 are located at at least one of the boundaries between the inclined surface 431 and the radially inner edge portion and the boundary between the inclined surface 431 and the first surface 41. In the end plate 4B of this embodiment, the corners 44 are located at two boundaries: the boundary between the inclined surface 431 and the radially inner edge portion and the boundary between the inclined surface 431 and the first surface 41. The corners 44 are rounded. This configuration makes it possible to prevent stress from concentrating at the corners 44.

[0037] 3. Modified end plate Next, a modified example of the end plate 4 will be described. The basic configuration of the modified example is the same as that of the embodiment described above using Figures 1 to 4, so the same components as before will be given the same reference numerals or names, and their description may be omitted. In addition, in the drawings, the illustration of components other than the characteristic parts will be omitted.

[0038] <3.1 Variation 1> Fig. 5 is a vertical cross-sectional view of an end plate 4B of Modification 1. Fig. 6 is a vertical cross-sectional perspective view of the end plate 4B of Modification 1 as seen from above in the axial direction. The end plate 4B of Modification 1 has a first surface 41, a second surface 42, a recess 45, and a corner 46.

[0039] The recess 45 is formed by a step 451 recessed in the axial direction. More specifically, in the end plate 4B of Modification 1, the recess 45 has a step 451 configured in a staircase shape descending in the axial direction from the first surface 41. The step 451 recesses axially downward from the first surface 41 in a region outside an intermediate portion Cr1 between the radial inner edge portion and the outer edge portion of the end plate 4.

[0040] According to the above configuration, the step 451 extends to a region outside the radial middle Cr1 of the end plate 4, thereby ensuring a thin region of the end plate 4 over a wide area. This makes it easier to propagate stress radially outward, and makes it possible to suppress deformation of the end plate 4.

[0041] In this embodiment, the step 451 is formed in a region outside the intermediate portion Cr1 between the radial inner edge and the outer edge of the end plate 4, but the aforementioned inclined surface 431 may also be formed in a region outside the intermediate portion Cr1 between the radial inner edge and the outer edge of the end plate 4.

[0042] The step 451 has a third surface 4511 and a fourth surface 4512. The third surface 4511 extends radially outward from the radially inner edge of the end plate 4. The fourth surface 4512 extends axially from the radially outer edge of the third surface 4511 and connects to the first surface 41. In other words, the fourth surface 4512 extends axially, connects to the third surface 4511 at its lower end, and connects to the first surface 41 at its upper end.

[0043] Corner portions 46 are disposed at at least one of the boundaries between the third surface 4511 and the radially inner edge portion, the boundary between the third surface 4511 and the fourth surface 4512, and the boundary between the fourth surface 4512 and the first surface 41. In the end plate 4B of Modification 1, corner portions 46 are disposed at three boundaries: the boundary between the third surface 4511 and the radially inner edge portion, the boundary between the third surface 4511 and the fourth surface 4512, and the boundary between the fourth surface 4512 and the first surface 41. Corner portions 46 are rounded. This configuration makes it possible to prevent stress from concentrating at corner portions 46.

[0044] Fig. 7 is a graph showing the relationship between the interference and stress of the end plate 4. The horizontal axis X in Fig. 7 represents the interference when the end plate 4 and the shaft 2 are joined by press-fitting. The vertical axis Y in Fig. 7 represents the maximum value of stress generated in the end plate 4 when the end plate 4 and the shaft 2 are joined.

[0045] FIG. 7 shows the results of simulation-based measurement of stress within the end plate 4. "Ex" is the measurement result of the end plate 4 of the above-described example having the inclined surface 431 in the recess 43, as described with reference to FIGS. 3 and 4. "Ev1" is the measurement result of the end plate 4 of the above-described modified example 1 having the step 451 in the recess 45, as described with reference to FIGS. 5 and 6. "Ce" is the measurement result of the end plate of the comparative example having no recess.

[0046] 7, it can be seen that the end plates 4 of the example (Ex) and the modified example 1 (Ev1) of the present disclosure are able to reduce the stress generated in the end plates 4 compared to the end plate of the comparative example (Ce) that does not have a recess, regardless of the tightening margin. This makes it possible to suppress deformation of the end plates 4.

[0047] <3.2 Variation 2> Fig. 8 is a vertical cross-sectional view of an end plate 4B of Modification 2. Fig. 9 is a vertical cross-sectional perspective view of the end plate 4B of Modification 2 as seen from above in the axial direction. The end plate 4B of Modification 2 has a first surface 41, a second surface 42, a recess 47, and a corner 48.

[0048] The recess 47 has a curved surface 471 at its bottom. In other words, the bottom surface of the recess 47 is configured with the curved surface 471. More specifically, in the end plate 4B of Modification 2, the recess 47 has the curved surface 471 that curves gradually away from the first surface 41 downward in the axial direction as it approaches the central axis C in the radial direction. The curved surface 471 is located in a region inside a middle point Cr1 between the radial inner edge and the radial outer edge of the end plate 4.

[0049] According to the above configuration, the curved surface 471 can easily propagate stress radially outward. Furthermore, by forming the curved surface 471 in a region inside the radial middle Cr1 of the end plate 4, it is possible to ensure a thick region of the end plate 4 over a wide range. This makes it possible to suppress deformation of the end plate 4.

[0050] Corner 48 is disposed at the boundary of the radially inner edge of curved surface 471. Corner 48 is rounded. This configuration makes it possible to prevent stress from concentrating on corner 48. The boundary between curved surface 471 and first surface 41 is smoothly connected.

[0051] <3.3 Variation 3> Fig. 10 is a vertical cross-sectional view of an end plate 4B of Modification 3. Fig. 11 is a vertical cross-sectional perspective view of the end plate 4B of Modification 3 as seen from the axial lower side. The end plate 4B of Modification 3 has a first surface 41, a second surface 42, a recess 51, and a corner 52.

[0052] In the end plate 4B of the third modification, the recess 51 is recessed axially upward from the second surface 42, which is the axial lower surface of the end plate 4B.

[0053] The recess 51 has an inclined surface 511 at its bottom. More specifically, in the end plate 4B of Modification 3, the recess 51 has an inclined surface 511 that gradually inclines away from the second surface 42 in the axial direction upward as it approaches the central axis C in the radial direction. With this configuration, the inclined surface 511 can facilitate the propagation of stress radially outward.

[0054] <3.4 Variation 4> Fig. 12 is a vertical cross-sectional view of an end plate 4B of Modification 4. Fig. 13 is a vertical cross-sectional perspective view of the end plate 4B of Modification 4 as seen from the axial lower side. The end plate 4B of Modification 4 has a first surface 41, a second surface 42, a recess 53, and a corner 54.

[0055] In the end plate 4B of the fourth modification, the recess 53 is recessed axially upward from the second surface 42, which is the axial lower surface of the end plate 4B.

[0056] The recess 53 is formed by a step 531 recessed in the axial direction. More specifically, in the end plate 4B of the fourth modification, the recess 53 has a step 531 configured in a staircase shape that rises in the axial direction from the second surface 42. With this configuration, the step 531 can facilitate the propagation of stress radially outward.

[0057] <3.5 Variation 5> Fig. 14 is a vertical cross-sectional view of an end plate 4B of Modification 5. Fig. 15 is a vertical cross-sectional perspective view of the end plate 4B of Modification 5 as seen from the axial lower side. The end plate 4B of Modification 5 has a first surface 41, a second surface 42, a recess 55, and a corner 56.

[0058] In the end plate 4B of the fifth modification, the recess 55 is recessed axially upward from the second surface 42, which is the axial lower surface of the end plate 4B.

[0059] The recess 55 has a curved surface 551 at its bottom. Specifically, in the end plate 4B of Modification 5, the recess 55 has the curved surface 551 that curves gradually away from the second surface 42 upward in the axial direction as it approaches the central axis C along the radial direction. With this configuration, the curved surface 551 can facilitate the propagation of stress radially outward.

[0060] In this embodiment, the motor 100 includes the rotor 1 having the above-described configuration and the stator 11. This configuration prevents stress from concentrating at the connection points between the end plates 4 and the shaft 2 in the motor 100, making it possible to suppress deformation of the end plates 4.

[0061] <4.Other> The above describes an embodiment of the present disclosure, but the scope of the present disclosure is not limited thereto, and the present disclosure can be implemented by adding, omitting, substituting, and making various other modifications to the configuration without departing from the spirit of the present disclosure. [Industrial Applicability]

[0062] The present disclosure can be used in rotors and motors. [Explanation of symbols]

[0063] 1 rotor, 2 shaft, 3 rotor core, 4 end plate, 4A end plate, 4B end plate, 4h through hole, 11 stator, 12 stator core, 12b core back portion, 12t teeth portion, 13 coil, 41 first surface, 42 second surface, 43 recess, 44 corner portion, 45 recess, 46 corner portion, 47 recess portion, 48...corner portion, 51...recess, 52...corner portion, 53...recess, 54...corner portion, 55...recess, 56...corner portion, 100...motor, 431...inclined surface, 451...step, 471...curved surface, 511...inclined surface, 531...step, 551...curved surface, 4511...third surface, 4512...fourth surface, C...central axis, Cr1...middle, Cx...axial center portion, L1...radial length

Claims

1. a shaft extending along a central axis; a rotor core disposed radially outward of the shaft and extending along the axial direction; end plates disposed at both axial ends of the rotor core, extending radially, and contacting the shaft at their radially inner edges; and The end plate is a first surface that faces the rotor core in the axial direction; a second surface that faces the opposite side to the first surface in the axial direction and is a flat surface; a recess adjacent to the shaft at a radially inner edge and recessed axially from the first surface; A rotor having

2. a shaft extending along a central axis; a rotor core disposed radially outward of the shaft and extending along the axial direction; end plates disposed at both axial ends of the rotor core, extending radially, and contacting the shaft at their radially inner edges; and The end plate is a first surface that faces the rotor core in the axial direction; a recess adjacent to the shaft at a radially inner edge and recessed axially from the first surface; and A rotor in which, in a region of the end plate facing axially opposite the first surface, an axial end portion of a radially inner edge portion and an axial end portion of a radially outer edge portion overlap in the radial direction.

3. a shaft extending along a central axis; a rotor core disposed radially outward of the shaft and extending along the axial direction; end plates disposed at both axial ends of the rotor core, extending radially, and contacting the shaft at their radially inner edges; and The end plate is a first surface that faces the rotor core in the axial direction; a recess adjacent to the shaft at a radially inner edge and recessed axially from the first surface; and The recess and the rotor core are opposed to each other in the axial direction.

4. The rotor according to claim 1 , wherein the recess is disposed on one side in the axial direction of a center portion of the end plate.

5. 5. The rotor according to claim 1, wherein the recess is disposed in a region more inward than a midpoint between a radial inner edge and an outer edge of the end plate, and the bottom of the recess has an inclined surface or a curved surface.

6. 6. The rotor according to claim 5, wherein the end plate has a rounded corner at at least one of a boundary between the inclined surface or the curved surface and a radially inner edge portion and a boundary between the inclined surface or the curved surface and the first surface or the second surface.

7. 5. The rotor according to claim 1, wherein the recess is formed by a step recessed in the axial direction in a region outside a midpoint between a radial inner edge and an outer edge of the end plate.

8. The step is a third surface extending radially outward from a radially inner edge portion of the end plate; a fourth surface extending in the axial direction from a radially outer edge portion of the third surface and connecting to the first surface or the second surface; and 8. The rotor according to claim 7, wherein the end plate has a rounded corner at at least one of a boundary between the third surface and a radially inner edge portion, a boundary between the third surface and the fourth surface, and a boundary between the fourth surface and the first surface or the second surface.

9. A rotor according to any one of claims 1 to 8; a stator disposed radially opposite the rotor; A motor having

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