Stator core support structure and rotating electric machine

Abstract

To provide a stator core support structure and a rotating electric machine that can reduce heat generation. [Solution] The stator core support structure of the embodiment is a stator core support structure applied to the stator of a rotating electric machine comprising a stator core and a magnetic shield disposed on the outer diameter side of the stator core, and comprises two core retainers that are attached so as to sandwich both the stator core and the magnetic shield from both sides in the stator axis direction and have extensions that extend toward the outer diameter side of the stator beyond the outer peripheral surface of the magnetic shield, and a support member that is integrally attached to a part of the outer peripheral surface of the magnetic shield and a part of the surface of each of the extensions of the two core retainers.

Description

Technical Field

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[0001] Embodiments of the present invention relate to a stator core support structure and a rotating electrical machine.

Background Art

[0002] Conventionally, a stator core that houses armature coils of a stator of a rotating electrical machine, for example, a stator core of a motor or a generator, mainly uses metal as its material. Since the stator core serves as a path for magnetic fields, it is made of a soft magnetic material such as an electromagnetic steel sheet, and forms a bulk body made of them or a laminated structure in which they are laminated.

[0003] The main role and effect of the stator core is to serve as a path for magnetic fields generated inside the rotating electrical machine and provide a driving force. Since iron is about 1000 times more permeable to magnetic fields than air, using a core enables efficient transfer of magnetic flux between the rotor and the armature coils of the stator, reduces leakage magnetic flux, and increases the driving force.

[0004] In addition to its electromagnetic role, the stator core also plays an important role in structural design. That is, the stator core has a plurality of grooves (hereinafter referred to as "slots") arranged circumferentially mainly on the inner diameter side of the structure, and by housing the armature coils in these slots, the stator as an assembled complete body can withstand external stresses such as vibration, etc., and has the role of improving mechanical strength.

[0005] Further, the stator core serves as a reference for the relative positional relationship such as the gap between each part, concentricity, shaft extension, etc., and reduces the manufacturing dimensional tolerance when assembling a motor or a generator, and helps to improve accuracy. Also, improving the manufacturing accuracy increases the possibility of realizing a product with motor performance close to the design.

Prior Art Documents

Patent Documents

[0006] [Patent Document 1] Japanese Patent Publication No. 2013-106471 [Patent Document 2] Japanese Patent Publication No. 2012-143064 [Overview of the project] [Problems that the invention aims to solve]

[0007] The stator core of a rotating electric machine, such as the stator core of an electric motor, often has various structures attached to its outer circumference. Among the structures attached to the stator core are support structures that provide stable support for the stator core. When attaching support structures to the stator core, joining or welding is generally used. In addition, the stator core is usually fixed by laminating and pressing electromagnetic steel sheets in the axial direction, then welding in the lamination direction on the outer circumference, and this external rotation process. Furthermore, in addition to external rotation, a plate material with a nose or legs, which is necessary during outfitting, may be joined to the outer circumference of the stator core by welding. In that case, depending on the type of electric motor applied, heat may be generated in the metal mass formed at the weld due to the influence of magnetic flux from the rotor.

[0008] Specifically, when a metal mass is formed in the welded area due to the heat of welding, and then exposed to a strong magnetic field originating from the rotor, eddy current losses occur in the metal mass formation area, causing heat generation. These losses reduce the efficiency of the rotating electric machine, and surrounding structures are also affected by the heat, further degrading the performance of the rotating electric machine.

[0009] For the reasons stated above, this heat generation is one of the major challenges in improving the efficiency of rotating electric machines, and careful attention must be paid to the method of fixing the stator core and the location of the stator.

[0010] This invention has been made in view of the above circumstances, and aims to provide a stator core support structure and a rotating electric machine that can reduce heat generation. [Means for solving the problem]

[0011] The stator core support structure of the embodiment is a stator core support structure applied to the stator of a rotating electric machine having a stator core and a magnetic shield disposed on the outer diameter side of the stator core, and comprises two core retainers that are attached so as to sandwich both the stator core and the magnetic shield from both sides in the stator axial direction and have extensions that extend toward the outer diameter side of the stator beyond the outer peripheral surface of the magnetic shield, and a support member that is integrally attached to a part of the outer peripheral surface of the magnetic shield and a part of the surface of each of the extensions of the two core retainers. [Effects of the Invention]

[0012] According to the present invention, it is possible to provide a stator core support structure and a rotating electric machine that can reduce heat generation. [Brief explanation of the drawing]

[0013] [Figure 1] Figure 1 is a schematic diagram showing an example of the configuration of a stator core support structure applied to the stator of a rotating electric machine according to the embodiment. [Figure 2] Figure 2 shows an example of the external appearance of a rotating electric machine, including a stator to which the stator core is fixed by the stator core support structure shown in Figure 1. [Figure 3] Figure 3 is a magnified view showing the structure near the central part 10 of the rotating electric machine shown in Figure 2. [Figure 4] Figure 4 is a diagram that shows a further enlarged view of the structure near the central part 10 of the rotating electric machine shown in Figure 3, and also shows some of the cross-sectional shapes. [Figure 5] Figure 5 schematically shows the axial cross-sectional shape near the axial center of the stator according to the first modified example. [Figure 6] Figure 6 schematically shows the axial cross-sectional shape near the axial center of the stator according to the second modified example. [Modes for carrying out the invention]

[0014] Hereinafter, embodiments will be described with reference to the drawings.

[0015] (Basic Configuration) FIG. 1 is a diagram schematically showing an example of the configuration of a stator core support structure applied to a stator of a rotating electric machine according to an embodiment. FIG. 2 is a diagram showing an example of the appearance of a rotating electric machine including a stator in which the stator core is fixed by the stator core support structure shown in FIG. 1.

[0016] The stator core support structure 20 shown in FIG. 1 is applied to a stator including a stator core 21 and a magnetic shield 22 disposed on the outer diameter side of the stator core 21. The stator is assumed to have two side fixing members 23 attached to both side surfaces in the axial direction of the stator core 21 and the magnetic shield 22. Iron or aluminum is used as the material for the stator core 21 and the side fixing members 23. A silicon steel sheet or a magnetic material containing iron, cobalt, etc. is used for the magnetic shield 22.

[0017] The stator core support structure 20 shown in FIG. 1 is a structure used to stably support and fix the stator core 21, and is provided at regular intervals in the circumferential direction of the stator (for example, 4 or 6, etc.) so as to be point-symmetric about the axis center.

[0018] This stator core support structure 20 includes, as various members, two core retainers 25, a support member 26, and a fastening member 27, and has a plurality of welded portions 31, 32, etc. where welding is performed at locations that require joining between the members. These welded portions are arranged so as to be present at least on the outer diameter side of the stator from the magnetic shield 22 in order to minimize the influence of heat generation due to eddy current loss on the stator core 21 side accompanying the field current generated from the rotor. Specifically, the position, range, number, and volume of each of these welded portions are determined in consideration of the heat input amount to the metal mass formed at the welded portions. No welded portion is present on the stator core 21. Details of the welded portions will be described later.

[0019] Regarding the fastening member 27 as well, in order to minimize the influence of heat generation due to eddy current loss on the stator core 21 side, it is arranged at a position that is separated from the magnetic shield 22 by a certain distance or more.

[0020] The two core retainers 25 are attached so as to sandwich both the stator core 21 and the magnetic shield 22 from both sides in the stator axis direction, and they have an extension part 25a that extends to the outer diameter side of the stator beyond the outer peripheral surface of the magnetic shield 22. The outer edge part on the outer diameter side of the stator of the extension part 25a is coupled and fixed to a bracket 24, which will be described later.

[0021] The support member 26 is a plate material having a "U" shape, and is integrally attached to a part of the surface on the outer peripheral side of the magnetic shield 22 and a part of the surface of each extension part 25a of the two core retainers 25. The fastening member 27 corresponds to, for example, a fastening bolt, and firmly couples and fixes each extension part 25a of the two core retainers 25 and the support member 26.

[0022] For the materials of the support member 26 and the fastening member 27, SUS (Steel Use Stainless) that guarantees a certain strength or more is used, and for the material of the core retainer 25, aluminum that contributes to weight reduction is used.

[0023] The rotating electric machine shown in FIG. 2 corresponds to, for example, an electric motor or a generator, and includes a stator and a rotor arranged on the inner diameter side thereof. Although not shown here, the rotor rotates around the rotation axis, the rotor is arranged at a certain distance from the stator, and a certain gap is provided between the stator and the rotor.

[0024] Furthermore, in the central part 10 of the rotating electric machine shown in Figure 2, it can be seen that the magnetic shield 22, two side fixing members 23, a support member 26, and a fastening member 27, as well as various welded parts 31-33, are present. In addition, at the ends 11 and 12 located on both sides of the central part 10 in the direction of the stator axis, it can be seen that there are two core retainers 25, as well as brackets 24 that cover the various mechanisms inside the ends 11 and 12. The outer edges of the core retainers 25 on the stator outer diameter side are connected and fixed to the brackets 24. In Figure 2, the ends of the armature coils 28, which will be described later, are partially visible through a window provided in the brackets 24. Note that in Figure 2, the brackets 24 are represented as semi-transparent so that the internal structure of the brackets 24 can be seen.

[0025] (Details of the stator core support structure and its surrounding structure) Next, with reference to Figures 3 and 4, the structure of the stator core support structure 20 and its surroundings will be described in more detail.

[0026] Figure 3 is an enlarged view of the structure near the central part 10 of the rotating electric machine shown in Figure 2. Figure 4 is a further enlarged view of the structure near the central part 10 of the rotating electric machine shown in Figure 3, and also shows some of the cross-sectional shapes. In these figures, elements common to Figures 1 and 2 are denoted by the same reference numerals.

[0027] As shown in Figure 4, the stator is provided with slots 29 at regular intervals in the circumferential direction, and an armature coil 28 is provided in each slot 29. An insulator (not shown) is provided between the slots 29 and the armature coil 28, and a wedge (not shown) is also provided to prevent the armature coil 28 from popping out. In addition, a refrigerant flow path (not shown) is provided inside the stator core 21 of the stator, with an opening for the flow of a refrigerant (cooling medium).

[0028] Figures 3 and 4 illustrate three types of welded joints 31-33.

[0029] The welded joint 31 connects the support member 26 and the magnetic shield 22, fixing the support member 26 to the magnetic shield 22.

[0030] The welded joint 32 connects the side fixing member 23 and the core holder 25, fixing the side fixing member 23 to the core holder 25.

[0031] The welded portion 33 is formed at the boundary between the portion of the support member 26 that is attached to a part of the outer surface of the magnetic shield 22 and the side fixing member 23, and the portion that is attached to a part of the surface of the extension portion of the core retainer 25. The welded portion 33 prevents the support member 26 from being separated at the boundary.

[0032] Furthermore, the portion of the support member 26 that is attached to a part of the surface of the extended portion of the core retainer 25 is fastened to the support member 26 by a fastening member 27.

[0033] In welding to form welds 31-33, the base material and the welding material are melted together and alloyed to fix them in place. There are various methods for this, but in all cases, depending on the area affected by welding (in the depth direction), the properties of the base material may deteriorate. Therefore, care should be taken to consider the affected area in order to minimize the deterioration of the characteristics of the rotating electric machine. The position, range, number, and capacity of each weld in welds 31-33 are determined, as described above, taking into account the amount of heat input to the metal block.

[0034] The support member 26 and the two core retainers 25 (as well as the fastening member 27 and welded parts 31-33) configured in this way play a role in stably fixing the structure consisting of the magnetic shield 22, the side fixing member 23, and the stator core 21.

[0035] Next, we will introduce two variations regarding the arrangement of the support member 26.

[0036] (First variation) Figure 5 schematically shows the axial cross-sectional shape near the axial center of the stator according to the first modified example.

[0037] As shown in Figure 5, a magnetic shield 22 is positioned on the outer diameter side of the stator core 21 via a fitting portion 42, and a support member 26 is positioned on the outer diameter side of the magnetic shield 22. The magnetic shield 22 has a pre-formed build-up portion 41 of a predetermined thickness, and the support member 26 is fixed by being embedded in the build-up portion 41. The material of the build-up portion 41 is the same as that of the magnetic shield 22.

[0038] The support member 26 is joined to the magnetic shield 22 by welding. Before welding begins, the support member 26 is positioned on top of the build-up portion 41 and is on the outer diameter side of the position shown in Figure 5. As the build-up portion 41 melts during welding, the support member 26 is embedded in the build-up portion 41 as shown in Figure 5 and moves toward the inner diameter side. Once melting is complete, the support member 26 is stably fixed within the build-up portion 41.

[0039] With this configuration, the support member 26 is firmly fixed to the magnetic shield 22, thereby stably supporting the magnetic shield 22 and the stator core 21.

[0040] (Second variation) Figure 6 schematically shows the axial cross-sectional shape near the axial center of the stator according to the second modified example.

[0041] As shown in Figure 6, a magnetic shield 22 is positioned on the outer diameter side of the stator core 21 via a fitting portion 42, and a support member 26 is positioned on the outer diameter side of the magnetic shield 22. In addition, tabs 51 are pre-formed on the magnetic shield 22 at a position that does not interfere with the installation of the support member 26. The material of the tabs 51 is the same as that of the magnetic shield 22. The tabs 51 also have through holes 52 for passing a support column. In this case, the support column may be made of resin. The tabs 51 may have a shape that extends in the direction of the stator axis, but for weight reduction, multiple tabs may be arranged at regular intervals in the direction of the stator axis. Both ends of the support column that passes through the through holes 52 are fixed to the two core retainers 25 described above.

[0042] This configuration allows the support columns passing through the through-holes 52 to stably support the magnetic shield 22 and the stator core 21, thus enabling the individual support members 26 to be made smaller and lighter.

[0043] As described in detail above, according to the embodiment, it is possible to provide a stator core support structure and a rotating electric machine that can reduce heat generation.

[0044] For example, by adopting the configuration described in the embodiment, it is possible to reduce the weight of the rotating electric machine and ensure the mechanical strength of the stator in the axial and radial directions, as well as reduce the effect of heat generation due to eddy current losses on the stator core side associated with the field current generated from the rotor, thereby improving the performance of the rotating electric machine.

[0045] Furthermore, according to the embodiment, while maintaining the manufacturing dimensional accuracy of the stator core or rotating electric machine, eddy current losses generated in the stator core can be reduced, and in addition to cooling the armature coil, the rotor installed on the inner diameter side of the stator core or the structure installed on the outer diameter side can be efficiently cooled.

[0046] Furthermore, according to the embodiment, it is possible to reduce the number of parts as much as possible while ensuring the characteristics required for a rotating electric machine, thereby achieving miniaturization and weight reduction.

[0047] While several embodiments of the present invention have been described, these embodiments are presented as examples only and are not intended to limit the scope of the invention. These novel embodiments can be carried out in a variety of other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims of the invention and its equivalents. [Explanation of symbols]

[0048] 1...Rotating electric machine, 10...Center section, 11,12...End section, 20...Stator core support structure, 21...Stator core, 22...Magnetic shield, 23...Side fixing member, 24...Bracket, 25...Core retainer, 25a...Extension section, 26...Support member, 27...Fastening member, 28...Armature coil, 29...Slot, 31~33...Welded section, 41...Build-up section, 42...Matching section, 51...Latch plate, 52...Through hole.

Claims

1. A stator core support structure applied to the stator of a rotating electric machine, comprising a stator core and a magnetic shield disposed on the outer diameter side of the stator core, Two core retainers are mounted so as to sandwich both the stator core and the magnetic shield from both sides in the stator axis direction, and each core retainer has an extension that extends toward the outer diameter of the stator beyond the outer circumferential surface of the magnetic shield, A support member is integrally attached to a part of the outer surface of the magnetic shield and a part of the surface of each of the two core retainers' extensions. Equipped with, Stator core support structure.

2. At least a portion of the support member has a plurality of welded joints, and these plurality of welded joints are located on the outer diameter side of the stator, The stator core support structure according to claim 1.

3. The aforementioned plurality of welded joints are Including a welded joint that joins the support member and the magnetic shield, The stator core support structure according to claim 2.

4. The aforementioned plurality of welded joints are The support member includes a welded portion at the boundary between the portion attached to a part of the outer surface of the magnetic shield and the portion attached to a part of the surface of each of the two core retainers' extensions, The stator core support structure according to claim 2.

5. Two side fixing members are attached to both sides of the stator core and the magnetic shield in the stator axis direction, A welded joint that connects the two side fixing members and the two core retainers, respectively. The stator core support structure according to claim 1, further comprising the above.

6. The system further comprises fastening members that connect the extensions of the two core retainers to the support member. The stator core support structure according to claim 1.

7. Multiple support members are provided at regular intervals in the circumferential direction of the stator. The stator core support structure according to claim 1.

8. The magnetic shield has a built-up portion with a predetermined thickness, and the support member is fixed by being embedded in the built-up portion. The stator core support structure according to claim 1.

9. The magnetic shield has ear plates formed in a position that does not interfere with the installation of the support member, and the ear plates have through holes for passing a support column through, and both ends of the support column passing through the through holes are fixed to the two core retainers. The stator core support structure according to claim 1.

10. A rotating electric machine comprising a stator whose stator core is supported by a stator core support structure according to any one of claims 1 to 9, and a rotor disposed at a certain distance from the stator.

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