Rotating electric machines

Abstract

The present invention provides a rotating electric machine capable of reducing leakage magnetic flux to suppress the increase in iron loss of the stator core, thereby suppressing the alternating current copper loss of the coil. The rotating electric machine includes: a stator including a stator core and a coil wound around the stator core; and a rotor disposed inside the stator core. The stator core includes: a back yoke portion configured in an annular shape and surrounding the rotor; and a tooth portion extending radially from the back yoke portion, with its front end facing the rotor disposed inside the back yoke portion via an air gap. A low iron loss portion is disposed within a space formed within the tooth portion. The tooth portion is configured to surround the low iron loss portion, and the iron loss density of the low iron loss portion is smaller than the iron loss density of the tooth portion. Furthermore, within the space of the tooth portion, the spacing between a first end portion of the low iron loss portion close to the air gap and the tooth portion is smaller than the spacing between a second end portion of the low iron loss portion away from the air gap and the tooth portion.

Description

Technical Field

[0001] The present invention relates to a rotating electrical machine. Background Art

[0002] In the prior art, a rotating electrical machine generally includes a stator and a rotor, wherein the rotor includes a rotor core and a rotating shaft disposed on the rotor core, and the stator includes a stator core and a coil wound on the stator core, with the rotor disposed inside the stator core. As shown in Patent Document 1, the stator core generally includes a back yoke portion configured in an annular shape and a tooth portion extending radially from the back yoke portion and facing the rotor. The tooth portion may be formed of an amorphous material and disposed in a groove of the back yoke portion facing the rotor, with an insulating component and / or a magnetic component further disposed at its end. Thus, compared to a back yoke portion formed of electromagnetic steel sheets, the tooth portion formed of an amorphous material has a lower saturation magnetic flux density, thereby increasing the AC copper loss of the coil due to the influence of the leakage magnetic flux, resulting in a poor iron loss reduction effect. Similarly, Patent Document 2 discloses the use of materials with different magnetic properties to form a stator core, but similar problems also exist. Therefore, when the stator core of a rotating electrical machine is made of different materials (such as electromagnetic steel sheets and amorphous materials), it is urgent to improve the problem of increased iron loss of the stator core.

[0003] [Prior art literature]

[0004] [Patent Document]

[0005] [Patent Document 1] Japanese Patent Publication No. 2019-161964

[0006] [Patent Document 2] International Patent Publication No. WO2018 / 069956 Summary of the Invention

[0007] The present invention provides a rotating electrical machine capable of reducing leakage magnetic flux to suppress an increase in the iron loss of a stator core, thereby suppressing the alternating current copper loss of a coil.

[0008] The present invention provides a rotating electrical machine, comprising: a stator including a stator core and a coil wound around the stator core; and a rotor disposed inside the stator core. The stator core includes a back yoke portion configured in an annular shape and surrounding the rotor; and a tooth portion extending radially from the back yoke portion, with its front end facing the rotor disposed inside the back yoke portion via an air gap. A low iron loss portion is disposed within a space formed within the tooth portion. The tooth portion is configured to surround the low iron loss portion, and the iron loss density of the low iron loss portion is smaller than the iron loss density of the tooth portion. Furthermore, within the space within the tooth portion, the spacing between a first end portion of the low iron loss portion, which is close to the air gap, and the tooth portion is smaller than the spacing between a second end portion of the low iron loss portion, which is distant from the air gap, and the tooth portion.

[0009] In one embodiment of the present invention, the low iron loss portion is fixed to the tooth portion by a bonding agent, and the bonding agent contains magnetic powder.

[0010] In one embodiment of the present invention, the bonding agent contains a foam material, and the bonding agent is disposed in the space of the tooth portion and on the second end portion of the low iron loss portion away from the air gap.

[0011] In one embodiment of the present invention, the bonding agent is further disposed on at least one of two opposite side surfaces of the low iron loss portion.

[0012] In one embodiment of the present invention, the low iron loss portion includes an amorphous material or a nanocrystalline material.

[0013] In one embodiment of the present invention, the back yoke portion of the stator core is provided with a coil groove, the coil is arranged in the coil groove and wound on the stator core, and the opening of the coil groove close to the air gap is formed with a covering portion of reduced width.

[0014] Based on the above, in a rotating electric machine according to the present invention, a stator includes a stator core and a coil wound around the stator core. The stator core includes an annular back yoke portion and a tooth portion extending radially from the back yoke portion and facing the rotor across an air gap. A low-iron-loss portion is disposed within a space formed within the tooth portion. The tooth portion is configured to surround the low-iron-loss portion. The low-iron-loss portion has an iron loss density lower than that of the tooth portion. Furthermore, within the space of the tooth portion, the spacing between a first end of the low-iron-loss portion, which is closer to the air gap, and the tooth portion is smaller than the spacing between a second end of the low-iron-loss portion, which is farther from the air gap, and the tooth portion. Thus, by providing the low-iron-loss portion with a low iron loss density within the tooth portion and by providing a small spacing between the first end of the low-iron-loss portion, which is closer to the air gap, and the low-iron-loss portion, which is closer to the air gap and the rotor, a large magnetic flux is allowed to pass near the rotor, thereby suppressing magnetic flux fluctuations and thereby suppressing an increase in the iron loss of the stator core. According to this, the rotating electric machine of the present invention can reduce the leakage magnetic flux to suppress the increase in the iron loss of the stator core, thereby suppressing the AC copper loss of the coil.

[0015] In order to make the above features and advantages of the present invention more clearly understood, embodiments are given below with reference to the accompanying drawings for detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is a schematic side view of a rotating electrical machine according to an embodiment of the present invention;

[0017] Figure 2 yes Figure 1 The enlarged schematic diagram of the rotating motor in area A is shown;

[0018] Figure 3 yes Figure 1 A side view schematic diagram of the back yoke and teeth of the stator core shown;

[0019] Figure 4 yes Figure 1 A side view schematic diagram of a low iron loss portion provided in the stator core shown;

[0020] Figure 5 yes Figure 4 Schematic side view of the low iron loss portion in other modified examples.

[0021] Description of reference numerals:

[0022] 50: Rotating motor;

[0023] 100: stator;

[0024] 110: stator core;

[0025] 112: back yoke;

[0026] 112a: coil groove;

[0027] 112b: covering portion;

[0028] 114: tooth;

[0029] 114a: front end;

[0030] 114b: ear;

[0031] 116: low iron loss part;

[0032] 116a: first end portion;

[0033] 116b: second end portion;

[0034] 116c, 116d: side view;

[0035] 118: bonding agent;

[0036] 120: coil;

[0037] 200: rotor;

[0038] A: Region;

[0039] d1, d2: interval;

[0040] G: air gap;

[0041] S: Space. DETAILED DESCRIPTION

[0042] Reference will now be made in detail to exemplary embodiments of the present invention, examples of which are illustrated in the accompanying drawings. Figure 1 is a side view schematic diagram of a rotating electrical machine according to an embodiment of the present invention, Figure 2 yes Figure 1 The enlarged schematic diagram of the rotating motor in area A is shown. Figure 3 yes Figure 1 The side view of the back yoke and teeth of the stator core is shown in FIG. Figure 4 yes Figure 1 The side view of the low iron loss portion of the stator core shown in FIG. Figure 5 yes Figure 4 The following is a schematic side view of the low iron loss part in other modified examples. Figures 1 to 5 The specific structure of the rotary motor 50 of this embodiment is described, but the rotary motor 50 is only one example of the present invention and the present invention is not limited thereto.

[0043] Please refer to Figure 1 and Figure 2In this embodiment, the rotating electrical machine 50 includes a stator 100 and a rotor 200. The stator 100 includes a ring-shaped stator core 110 and a coil 120 wound around the stator core 110. The rotor 200 is disposed inside the stator core 110 and is rotatable relative to the stator 100. The relative positions of the stator 100 and the rotor 200, their actuation methods, and the specific structure of the rotor 200 can be determined by reference to existing technologies or adjusted as needed, and the present invention is not limited thereto.

[0044] Furthermore, in this embodiment, if Figure 1 As shown, the stator core 110 includes a back yoke portion 112 and a tooth portion 114. The back yoke portion 112 is annular and surrounds the rotor 200. The tooth portion 114 extends radially from the back yoke portion 112, with its front end 114a facing the rotor 200 disposed inside the back yoke portion 112 across an air gap G. Furthermore, the back yoke portion 112 of the stator core 110 is provided with a coil groove 112a. The coil 120 is disposed within the coil groove 112a and wound around the stator core 110. The opening of the coil groove 112a, near the air gap G, is formed with a reduced width covering portion 112b.

[0045] So, like Figure 3 As shown, the back yoke portion 112 and the tooth portion 114 of the stator core 110 can be made of the same electromagnetic steel plate. For example, a piece of electromagnetic steel plate is used to make a circular ring structure as the back yoke portion 112, and a plurality of coil grooves 112a are made on the inner side of the back yoke portion 112, so that the protruding portions between the coil grooves 112a can serve as the tooth portion 114, and as shown in FIG. Figure 1 The coil 120 shown can be arranged in the coil groove 112a and wound on the stator core 110. Furthermore, by providing an ear portion 114b extending laterally to opposite sides at the front end 114a of the tooth portion 114, a covering portion 112b that reduces the width of the opening can be formed at the opening of the adjacent coil groove 112a. Thus, the back yoke portion 112, the coil groove 112a and the tooth portion 114 of the stator core 110 are constructed using the electromagnetic steel plate as the basic skeleton of the stator core 110. Furthermore, by providing an ear portion 114b extending laterally to opposite sides at the front end 114a of the tooth portion 114, the iron loss caused by the high-pitched wave generated in the coil groove 112a can be reduced, and the rotor 200 (shown in FIG. 1 ) can be suppressed when there is no load. Figure 1 ) surface, thereby reducing the iron loss of the stator core 110 and the AC copper loss of the coil 120.

[0046] In addition, in this embodiment, the space S formed inside the teeth 114 of the stator core 110 (shown in FIG. Figure 3 ), is provided with a low iron loss portion 116 (such as Figure 1 and Figure 2 As shown), the tooth portion 114 is configured to surround the low iron loss portion 116. That is, after the back yoke portion 112, the coil groove 112a and the tooth portion 114 of the stator core 110 are made of the same electromagnetic steel sheet, a through hole is further punched on the tooth portion 114 to serve as the space S, and then the low iron loss portion 116 is inserted into and fixed in the space S of the tooth portion 114. The space S formed inside the tooth portion 114 is different from the coil groove 112a, which is open on the inner side of the stator core 110. That is, the low iron loss portion 116 and the air gap G are separated by the front end 114a of the tooth portion 114 (as shown). Figure 1 and Figure 2 As shown in FIG. 1 , the low iron loss portion 116 disposed within the space S does not extend from the front end 114a of the tooth portion 114 to the air gap G. With this arrangement, the low iron loss portion 116 is disposed within the tooth portion 114 formed of electromagnetic steel sheets, allowing the magnetic flux of the back yoke portion 112 to flow smoothly, thereby preventing the magnetic flux from being deflected and reducing losses.

[0047] Furthermore, in this embodiment, the iron loss density of the low iron loss portion 116 is smaller than that of the tooth portion 114. In detail, as mentioned above, the tooth portion 114 and the back yoke portion 112 can be made integrally from the same electromagnetic steel plate. In contrast, the low iron loss portion 116 includes an amorphous material or a nanocrystalline material, but as long as the iron loss density of the low iron loss portion 116 is smaller than that of the tooth portion 114, the present invention does not limit the type of material used for the low iron loss portion 116. In this way, a low iron loss portion 116 with a low iron loss density is provided in the tooth portion 114, that is, a low iron loss portion 116 with a low iron loss density is provided in a part of the tooth portion 114. Compared with using a material with a high iron loss density to make the entire tooth portion 114 (such as making it integrally from the same electromagnetic steel plate and the back yoke portion 112), the increase in iron loss of the stator core 110 can be suppressed.

[0048] Furthermore, in this embodiment, if Figure 2 As shown in the partially enlarged view of FIG, the tooth portion 114 and the low-iron-loss portion 116 are arranged relative to each other such that, within the space S of the tooth portion 114, the distance d1 between the first end 116a of the low-iron-loss portion 116, which is close to the air gap G, and the tooth portion 114 is smaller than the distance d2 between the second end 116b of the low-iron-loss portion 116, which is distant from the air gap G, and the tooth portion 114. Preferably, the distance d1 between the first end 116a of the low-iron-loss portion 116, which is close to the air gap G, and the tooth portion 114 can be zero, that is, the first end 116a of the low-iron-loss portion 116 can abut against the wall of the space S of the tooth portion 114. In this manner, the low-iron-loss portion 116 is configured to approach the air gap G and the rotor 200. This allows a large magnetic flux to pass through on the side close to the rotor 200, suppressing magnetic flux fluctuations and thereby reducing the increase in iron loss in the stator core 110.

[0049] Furthermore, if Figure 2 and Figure 4 As shown, the low-iron-loss portion 116 is fixed to the tooth portion 114 with an adhesive 118. The adhesive 118 may contain magnetic powder or further contain a foaming material. However, the present invention does not limit the type of material used for the adhesive 118, and it can be adjusted according to needs. Thus, the adhesive 118 can be made into a sheet-like structure and attached to the low-iron-loss portion 116 in advance. After the low-iron-loss portion 116 is inserted into the space S of the tooth portion 114, the stator is heated, which can expand the foaming material in the adhesive 118 and fix the low-iron-loss portion 116 within the space S of the tooth portion 114.

[0050] Alternatively, the adhesive 118 can be injected into the mold after the low iron loss portion 116 is inserted into the space S of the teeth 114. In this case, since the teeth 114 are configured to surround the low iron loss portion 116, that is, the space S of the teeth 114 is not open inside the stator core 110, even if the adhesive 118 is injected, the material of the adhesive 118 (such as a resin material) is unlikely to leak out of the space S during the injection process.

[0051] Furthermore, in this embodiment, the adhesive 118 is disposed within the space S of the tooth portion 114 and on the second end 116b of the low-iron-loss portion 116, distal from the air gap G, but not on the first end 116a of the low-iron-loss portion 116, proximal to the air gap G. This arrangement ensures that at least the adhesive 118 is interposed between the second end 116b of the low-iron-loss portion 116, distal from the air gap G, and the tooth portion 114 (i.e., the gap d2 is at least greater than zero). In contrast, the adhesive 118 containing the foamed material disposed on the second end 116b of the low-iron-loss portion 116 expands, pressing the first end 116a of the low-iron-loss portion 116 toward the wall of the space S in the tooth portion 114, toward the air gap G. Consequently, the first end 116a of the low-iron-loss portion 116 abuts against the wall of the space S in the tooth portion 114 (i.e., the gap d1 can be zero). This reduces magnetic flux fluctuations and iron loss by suppressing magnetic impedance.

[0052] Furthermore, in this embodiment, if Figure 4 As shown in the figure, the bonding agent 118 is further arranged on the two opposite side surfaces 116c and 116d of the low iron loss portion 116, that is, the bonding agent 118 is provided on the second end portion 116b and the two opposite side surfaces 116c and 116d of the low iron loss portion 116 except the first end portion 116a close to the air gap G. Figure 1The coil 120 wound around the stator core 110 (shown in FIG) is fixed in the space S of the tooth portion 114 by the winding force provided by the coil 120. The coil 120 itself is also fixed in the space S of the tooth portion 114 by the bonding force of the adhesive 118. By increasing the fixing area of ​​the adhesive 118, the durability and reliability of the low iron loss portion 116 against vibration and thermal stress can be improved. Furthermore, by filling the gaps between the opposing side surfaces 116c and 116d of the low iron loss portion 116 and the left and right walls of the tooth portion 114 with the adhesive 118, the compressive stress caused by the winding force of the coil 120 is replaced, thereby achieving good magnetic properties.

[0053] In addition, as a modified example, Figure 5 As shown, the adhesive 118 is disposed in the space S of the tooth portion 114 and on the second end portion 116b of the low iron loss portion 116 away from the air gap G, and further disposed on one side surface 116d of the low iron loss portion 116. In order to provide a good fixing effect to replace the compressive stress caused by the winding force of the coil 120, the adhesive 118 is at least as thick as Figure 5 As shown in FIG, the low iron loss portion 116 is provided on the second end portion 116b and one of the two opposite side surfaces 116c and 116d. The preferred method is as follows Figure 4 As shown, the adhesive 118 is disposed on the second end portion 116b and the two opposing side surfaces 116c and 116d. However, in other variations not shown, the adhesive 118 may be disposed only on the second end portion 116b, or the adhesive 118 may not be disposed, and the coil 120 may be secured solely by the compressive stress generated by the winding force. The present invention does not limit the placement of the adhesive 118 or whether it is disposed, and it can be adjusted as needed.

[0054] In summary, in the rotating electrical machine of the present invention, the stator includes a stator core and a coil wound around the stator core. The stator core includes an annular back yoke portion and a tooth portion extending radially from the back yoke portion and facing the rotor across an air gap. A low-iron-loss portion is disposed within a space formed within the tooth portion. The tooth portion is configured to surround the low-iron-loss portion. The low-iron-loss portion has an iron loss density lower than that of the tooth portion. Furthermore, within the space within the tooth portion, the spacing between a first end portion of the low-iron-loss portion, which is closer to the air gap, and the tooth portion is smaller than the spacing between a second end portion of the low-iron-loss portion, which is farther from the air gap, and the tooth portion. Preferably, the low-iron-loss portion is secured to the tooth portion with an adhesive containing magnetic powder or further containing a foamed material. Thus, a low-iron-loss portion with a low iron-loss density is provided in the tooth portion. The low-iron-loss portion is arranged so that the gap between the first end portion near the air gap and the tooth portion is small, and the portion is arranged toward the air gap and the rotor. This allows a large magnetic flux to pass near the rotor, suppressing magnetic flux fluctuations and thereby reducing increases in stator core iron loss. Consequently, the rotating electric machine of the present invention can reduce leakage magnetic flux, suppress increases in stator core iron loss, and thereby reduce AC copper loss in the coil.

[0055] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A rotating electrical machine comprising: The stator comprises a stator core and a coil wound around the stator core; as well as The rotor is arranged inside the stator core. The stator core comprises: a back yoke portion configured in an annular shape and surrounding the rotor; and The tooth portion is formed by extending radially from the back yoke portion, and its front end faces the rotor provided inside the back yoke portion via an air gap, wherein: The rotating electrical machine is characterized in that A low iron loss portion is arranged in a space formed inside the tooth portion, the tooth portion is configured to surround the low iron loss portion, and the iron loss density of the low iron loss portion is smaller than the iron loss density of the tooth portion, and In the space of the tooth portion, a distance between a first end portion of the low iron loss portion close to the air gap and the tooth portion is smaller than a distance between a second end portion of the low iron loss portion far from the air gap and the tooth portion.

2. The rotating electrical machine according to claim 1, wherein: The low iron loss portion is fixed to the tooth portion with a bonding agent, and The bonding agent contains magnetic powder.

3. The rotating electrical machine according to claim 2, wherein: The bonding agent contains a foaming material, and The bonding agent is disposed in the space of the teeth portion and on the second end portion of the low iron loss portion that is away from the air gap.

4. The rotating electrical machine according to claim 3, wherein: The bonding agent is further disposed on at least one of two opposing side surfaces of the low iron loss portion.

5. The rotating electrical machine according to claim 1, wherein The back yoke portion of the stator core is provided with a coil groove, The coil is arranged in the coil groove and wound on the stator core, and An opening of the coil groove close to the air gap is formed with a covering portion having a reduced width.

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