Rotors and Rotating Electric Machines

Abstract

To improve the cooling efficiency of a rotor without increasing the axial size.SOLUTION: The rotor has a rotor core, a magnet embedded in the rotor core, and an end plate arranged at the axial end of the rotor core and facing the magnet to prevent the magnet from scattering. The end plate has a groove on a surface facing the rotor core that is recessed on the side opposite the rotor core. The groove does not face the magnet in the axial direction. the groove has a fan inlet part open at the outer radial end of the end plate, a fan outlet part open at the outer radial end of the end plate at a circumferential position that does not match the fan inlet part, and a fan passage connecting the fan inlet part and the fan outlet part.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a rotor and a rotating electric machine.

Background Art

[0002] In the cooling of an inner rotor type motor, regarding the cooling of the stator arranged radially outside due to the positional relationship between the rotor and the stator, it can be directly cooled from the outside in the radial direction by water cooling. However, since the rotor arranged radially inside is cooled through the stator from the outside in the radial direction, there is a possibility that the cooling of the rotor may not be sufficient.

[0003] Patent Document 1 discloses a structure for cooling a rotor by providing a fan for circulating a fluid and heat radiating fins protruding axially outside the rotor.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the structure of Patent Document 1, due to the provision of a fan and fins, the axial size of the motor becomes large.

[0006] An object of the present invention is to improve the cooling efficiency of a rotor without increasing the axial size.

Means for Solving the Problems

[0007] A rotor according to one aspect of the present invention comprises a rotor core, a magnet embedded in the rotor core, and an end plate positioned at the axial end of the rotor core and facing the magnet to prevent the magnet from scattering, wherein the end plate has a groove on the surface facing the rotor core that is recessed on the side opposite to the rotor core, the groove does not face the magnet in the axial direction, the groove has an air inlet opening at the radially outer end of the end plate, an air outlet opening at the radially outer end of the end plate at a circumferential position not coinciding with the air inlet, and an air passage connecting the air inlet and the air outlet.

[0008] In the rotor according to one embodiment described above, the magnets are arranged in multiple layers in the radial direction.

[0009] In the rotor according to one embodiment described above, the air passage faces the rotor core between a predetermined layer of the plurality of layers formed by the magnet and a layer adjacent to the predetermined layer.

[0010] In the rotor according to the above embodiment, the end plates are arranged at one axial end and the other axial end of the rotor core.

[0011] In the rotor according to the above embodiment, the width of the air inlet is greater than the width of the air passage.

[0012] A rotating electric machine according to one aspect of the present invention has a stator and a rotor that faces the stator with a gap between them. [Effects of the Invention]

[0013] According to one aspect of the present invention, the cooling efficiency of the rotor can be improved without increasing the axial size. [Brief explanation of the drawing]

[0014] [Figure 1] This is a perspective view of a rotor according to the first embodiment of the present invention. [Figure 2]This is a diagram showing the end plate 103. [Figure 3] This diagram shows one pole of the axial side surface of the rotor core 101 according to the first embodiment, cut out in a sector shape centered on the central axis J of the shaft 40. [Figure 4] This diagram shows one pole of the axial side surface of the rotor core 101 according to the second and third embodiments, cut out in a sector shape around the central axis J of the shaft 40. [Modes for carrying out the invention]

[0015] The rotor according to an embodiment of the present invention will be described below with reference to the drawings. Note that in the following drawings, the scale and number of components in each structure may differ from the actual structure in order to make the components easier to understand. Also, for ease of viewing, each component is shown in a schematic form that differs from the actual shape.

[0016] Furthermore, in the drawings, the XYZ coordinate system is shown as a three-dimensional Cartesian coordinate system where appropriate. In the XYZ coordinate system, the Z-axis direction is parallel to the axis direction of the central axis J shown in Figure 1. The Y-axis direction is the vertical direction in the radial direction relative to the central axis J, as shown in Figure 2. The X-axis direction is perpendicular to both the Y-axis and Z-axis directions. In the X-axis, Y-axis, and Z-axis directions, the side indicated by the arrow in the drawing is the + side, and the opposite side is the - side.

[0017] In the following description, the positive side (+Z side) in the Z-axis direction is referred to as "one side", and the negative side (-Z side) in the Z-axis direction is referred to as "the other side". Note that the one side and the other side are merely names used for the purpose of explanation and do not limit the actual positional relationship and direction. Also, unless otherwise specified, the direction parallel to the central axis J (Z-axis direction) is simply referred to as the "axial direction", the radial direction centered on the central axis J is simply referred to as the "radial direction", and the circumferential direction centered on the central axis J, that is, around the axis of the central axis J is simply referred to as the "circumferential direction". The side approaching the central axis J in the radial direction is referred to as the "radial inner side", and the side moving away from the central axis J is referred to as the "radial outer side". Also, taking the circumferential direction of the central axis J as the θ direction, the side pointed by the arrow shown in the figure is the +θ side, and the opposite side is the - side. The positive side (+θ side) in the θ direction is referred to as "one side", and the negative side (-θ side) in the θ direction is referred to as "the other side".

[0018] In this specification, "extending in the axial direction" includes not only the case of strictly extending in the axial direction (Z-axis direction), but also the case of extending in a direction inclined within a range of less than 45° with respect to the axial direction. Also, in this specification, "extending in the radial direction" includes not only the case of strictly extending in the radial direction, that is, in a direction perpendicular to the axial direction (Z-axis direction), but also the case of extending in a direction inclined within a range of less than 45° with respect to the radial direction. Also, "parallel" includes not only the case of being strictly parallel, but also the case of being inclined at an angle of less than 45° to each other.

[0019] <First Embodiment> FIG. 1 is a perspective view showing a rotor according to the first embodiment of the present invention. The rotor 100 is a rotor of a rotating electrical machine (not shown). This rotating electrical machine is an inner rotor type radial gap motor, and as will be described later with reference to FIG. 3, it is an embedded magnet type synchronous motor (IPM) configured by embedding magnets 105a, 105b, and 105c, which are permanent magnets, in a rotor core 101. This rotating electrical machine has a substantially cylindrical stator (not shown) and a rotor 100 disposed opposite to the inner side in the radial direction of the stator with a gap therebetween.

[0020] The rotor 100 has a rotor core 101, a shaft 102, an end plate 103, and an end plate 104. The shaft 102 extends along the central axis J. The rotor core 101 is a cylindrical member, and the shaft 102 is fixed to its inner circumference. The shaft 102 is coaxial with the rotor core 101. The shaft 102 is fixed to the rotor core 101 and supported by a bearing (not shown). The rotor core 101 and the shaft 102 rotate about the central axis J as the rotation axis in the +θ direction (clockwise when viewed from the +Z side). The end plate 103 is fixed to one end of the rotor core 101 in the axial direction. The end plate 104 is fixed to the other end of the rotor core 101 in the axial direction.

[0021] FIG. 2 is a view showing the end plate 103 shown in FIG. 1. FIG. 2(A) is a side view of the end plate 103 viewed from the +Z side. FIG. 2(B) is a side view of the end plate 103 viewed from the -Z side. The end plate 104 is different from the end plate 103 only in that the axial direction is opposite to that of the end plate 103, so the description of the end plate 104 is omitted.

[0022] The end plate 103 is a disk-shaped member and has a through hole 103a through which the shaft 102 penetrates on the inner side in the radial direction. The surface on the other side of the end plate 103 in the axial direction faces the surface on one side of the rotor core 101 in the axial direction. The surface on the other side of the end plate 103 in the axial direction contacts the surface on one side of the rotor core 101 in the axial direction. The end plate 103 is fixed to the rotor core 101.

[0023] The end plate 103 has a ventilation passage 103d formed by a groove recessed on the other side in the axial direction on the surface on the other side in the axial direction. The ventilation passage 103d is formed by a groove recessed on the side opposite to the rotor core 101. The ventilation passage 103d has a ventilation inlet portion 103c opened at the outer end in the radial direction at one end in the circumferential direction. The ventilation inlet portion 103c is formed by a groove recessed on the side opposite to the rotor core 101. The ventilation passage 103d has a ventilation outlet portion 103b opened at the outer end in the radial direction at the other end in the circumferential direction. The ventilation outlet portion 103b is formed by a groove recessed on the side opposite to the rotor core 101.

[0024] The circumferential position of the air inlet 103c does not coincide with the circumferential position of the air outlet 103b. The air inlet 103c is located one circumferential side (+θ side) of the air outlet 103b. The end plate 103 has an air outlet 103b, an air inlet 103c, and an air passage 103d.

[0025] The end plate 103 rotates in the +θ direction together with the rotor core 101. This rotation causes air to flow from the air inlet 103c into the air passage 103d. Furthermore, the air that flows from the air inlet 103c into the air passage 103d flows toward the -θ side. The air that has flowed toward the -θ side in the air passage 103d is then discharged to the outside of the rotor 100 from the air outlet 103b. The air passage 103d is in contact with the rotor core 101 on the other axial side, and the air flowing through the air passage 103d cools the axial surface of the rotor core 101. According to this embodiment, the rotor core 101 can be cooled without providing fans or fins, and the cooling efficiency of the rotor can be improved without increasing the axial size.

[0026] In the vicinity of the air intake 103c, the radially outer side of the airflow passage 103d is located on one side in the circumferential direction (+θ side) more than the radially inner side. This allows for smoother airflow into the airflow passage 103d when the rotor 100 rotates.

[0027] The width (circumferential length) of the air inlet section 103c is greater than the width of the air passage 103d downstream of the air inlet section 103c. This allows for smoother airflow into the air passage 103d when the rotor 100 rotates.

[0028] In the vicinity of the air outlet 103b, the radially outer side of the air passage 103d is located on the other side in the circumferential direction (-θ side) more than the radially inner side. This allows for smoother air discharge from the air passage 103d to the outside when the rotor 100 rotates.

[0029] Figure 3 shows a sector-shaped section of one pole on one axial side of the rotor core 101 according to the first embodiment, centered on the central axis J of the shaft 40. The rotor core 101 has multiple configurations similar to those shown in Figure 3, in the circumferential direction, corresponding to the number of poles.

[0030] The rotor 100 has magnets 105a, 105b, and 105c. The magnets 105a, 105b, and 105c are permanent magnets. The rotor core 101 has through holes that penetrate axially and accommodate the magnets 105a, 105b, and 105c. The magnets 105a, 105b, and 105c penetrate the rotor core 101 axially by being accommodated in the through holes of the rotor core 101 and are fixed to the rotor core 101.

[0031] Magnet 105a is positioned such that its longitudinal direction on the surface of the rotor core 101 perpendicular to the axial direction is perpendicular to the radial direction. Magnets 105b and 105c are positioned to form a V-shape on the surface of the rotor core 101 perpendicular to the axial direction.

[0032] The radial position where each magnet is placed is called a layer. Magnet 105a is the first layer magnet, positioned radially outward compared to the other magnets. Magnets 105b and 105c are the second layer magnets, positioned radially outward from magnet 105a.

[0033] The grooves of the end plate 103, namely the air inlet 103c, air outlet 103b, and air passage 103d, do not face the magnets 105a, 105b, and 105c in the axial direction. As a result, the end plate 103 prevents the magnets 105a, 105b, and 105c from shifting in the axial direction.

[0034] The air passage 103d faces the rotor core 101 between the first layer formed by magnet 105a and the second layer formed by magnets 105b and 105c, which are adjacent to the first layer. This allows for efficient cooling of the area between the first and second layers of magnets in the rotor core 101.

[0035] Furthermore, by forming grooves in the end plate 103 so as to face the portion of the rotor core 101 between the magnets, the leakage flux linked to the end plate 103 is reduced, thereby reducing losses.

[0036] In the first embodiment, there was one magnet 105a in the first layer, but each phase may be composed of multiple magnets. In the second embodiment, an example is shown where there are multiple magnets in the first layer.

[0037] Furthermore, while the first embodiment describes a double magnet arrangement having a first layer of magnets and a second layer of magnets, the present invention is not limited to this, and may also have a multi-layer magnet arrangement including a third layer and beyond of magnets. The third embodiment shows an example of a three-layer magnet arrangement.

[0038] Figure 4 is a diagram showing one pole of the axial side surface of the rotor core 101 according to the second and third embodiments, cut out in a sector shape around the central axis J of the shaft 40.

[0039] <Second Embodiment> Figure 4(A) shows a diagram of one pole on one axial side of the rotor core 101 according to the second embodiment, cut out in a sector shape around the central axis J of the shaft 40. The rotor core 101 has multiple configurations similar to the one shown in Figure 4(A) in the circumferential direction, corresponding to the number of poles.

[0040] The rotor 100 has magnets 105d, 105e, 105f, and 105g. Magnets 105d and 105e are arranged to form a V shape on the surface of the rotor core 101 perpendicular to the axial direction. Magnets 105f and 105g are arranged to form a V shape on the surface of the rotor core 101 perpendicular to the axial direction.

[0041] Magnets 105d and 105e are the first layer of magnets, positioned radially outward compared to the other magnets. Magnets 105f and 105g are the second layer of magnets, positioned radially outward after magnets 105d and 105e.

[0042] The end plate 103 has an air passage 103d on its other axial side surface, which consists of a groove recessed in one axial direction. The air passage 103d of the end plate 103 does not face the magnets 105d, 105e, 105f, and 105g in the axial direction. As a result, the end plate 103 prevents the magnets 105d, 105e, 105f, and 105g from shifting in the axial direction.

[0043] The air passage 103d faces the rotor core 101 between the first layer formed by magnets 105d and 105e and the second layer formed by magnets 105f and 105g, which are adjacent to the first layer. This allows for efficient cooling of the area between the first and second layers of magnets in the rotor core 101.

[0044] <Third Embodiment> Figure 4(B) shows a sector-shaped section of one pole on one axial side of the rotor core 101 according to the third embodiment, centered on the central axis J of the shaft 40. The rotor core 101 has multiple configurations similar to those shown in Figure 4(B) in the circumferential direction, corresponding to the number of poles.

[0045] The rotor 100 has magnets 105d, 105e, 105f, 105g, 105h, and 105i. Magnets 105d and 105e are arranged to form a V shape on the surface of the rotor core 101 perpendicular to the axial direction. Magnets 105f and 105g are arranged to form a V shape on the surface of the rotor core 101 perpendicular to the axial direction. Magnets 105h and 105i are arranged to form a V shape on the surface of the rotor core 101 perpendicular to the axial direction.

[0046] Magnets 105d and 105e are the first layer of magnets, positioned radially outward compared to the other magnets. Magnets 105f and 105g are the second layer of magnets, positioned radially outward after magnets 105d and 105e. Magnets 105h and 105i are the third layer of magnets, positioned radially outward after magnets 105f and 105g.

[0047] The end plate 103 has air passages 103d and 103e on its other axial side surface, which consist of grooves recessed in one axial direction. The air passages 103d and 103e of the end plate 103 do not face the magnets 105d, 105e, 105f, 105g, 105h, and 105i in the axial direction. As a result, the end plate 103 prevents the magnets 105d, 105e, 105f, 105g, 105h, and 105i from shifting in the axial direction.

[0048] The air passage 103d faces the rotor core 101 between the first layer formed by magnets 105d and 105e and the second layer formed by magnets 105f and 105g, which are adjacent to the first layer. This allows for efficient cooling of the area between the first and second layers of magnets in the rotor core 101.

[0049] The air passage 103e faces the rotor core 101 between the second layer formed by magnets 105f and 105g and the third layer formed by magnets 105g and 105i, which is adjacent to the second layer. This allows for efficient cooling of the area between the second and third layers of magnets in the rotor core 101.

[0050] The end plate 103 may have at least one of the air passages 103d and 103e.

[0051] The present invention is not limited to the embodiments described above, and various improvements and design modifications may be made without departing from the spirit of the invention. In addition, the embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of the present invention is indicated by the claims rather than by the above description, and all modifications within the meaning and scope equivalent to the claims are intended to be included. [Explanation of symbols]

[0052] 100...Rotor, 101...Rotor core, 102...Shaft, 103, 104...End plates

Claims

1. Rotor core and The magnet embedded in the rotor core, An end plate is positioned at the axial end of the rotor core and faces the magnet to prevent the magnet from scattering, It has, The end plate has a groove on the surface facing the rotor core that is recessed on the side opposite to the rotor core, The groove portion does not face the magnet in the axial direction. The groove portion includes an air inlet portion that opens to the radially outer end of the end plate, an air outlet portion that opens to the radially outer end of the end plate at a circumferential position not coinciding with the air inlet portion, and an air passage connecting the air inlet portion and the air outlet portion. A rotor characterized by the following features.

2. The magnet is arranged in a manner that forms multiple layers in the radial direction. The rotor according to feature 1.

3. The air passage is located between a predetermined layer of the plurality of layers formed by the magnet and a layer adjacent to the predetermined layer, facing the rotor core. The rotor according to feature 2.

4. The end plates are positioned at one axial end and the other axial end of the rotor core. The rotor according to feature 1.

5. The width of the air inlet is greater than the width of the air passage. The rotor according to feature 1.

6. The rotor comprises a stator and a rotor facing the stator with a gap between them. The rotating electric machine according to feature 1.

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