Rotating electric machine

Abstract

A rotating electrical machine is provided. The present invention reduces the necessity of sealing and does not require burn-in, and efficiently cools a stator core. Disclosed is a rotating electrical machine provided with: a rotor; a stator core having a slot in which a winding that can be energized is disposed; and a cylindrical member having a cylindrical shape centered on the rotational axis of the rotor, having elasticity capable of expanding and contracting in the radial direction, and having thermal conductivity, the cylindrical member having a refrigerant flow path between the inner peripheral surface and the outer peripheral surface, and being provided to the stator core such that the inner peripheral surface is in close contact with the outer peripheral surface of the stator core.

Description

Technical Field

[0001] This disclosure relates to rotating electrical machines. Background Technology

[0002] There is a known technology in which the outer circumferential surface of the stator core is covered by a waterproof coating, and the space enclosed by the coating, the inner circumferential surface of the shell, and a pair of seals on both axial ends is used as a refrigerant flow path.

[0003] Patent Document 1: Japanese Patent Application Publication No. 2019-134567

[0004] However, in the prior art described above, there is a problem that when the axial ends are sealed with a sealing part after being covered by a waterproof coating, it is not easy to ensure long-term sealing.

[0005] In contrast, while the method of embedding aluminum water jackets into the stator core eliminates these problems, it also introduces stress on the stator core, which worsens iron losses. Furthermore, there are issues such as the need to heat the casing during embedding and the difficulty in embedding shapes other than cylindrical ones. Summary of the Invention

[0006] Therefore, in one respect, the purpose of this disclosure is to reduce the necessity of sealing and eliminate the need for burning, while on the other hand, to efficiently cool the stator core.

[0007] In one aspect, a rotary electric motor is provided, comprising: a rotor; a stator core having slots and energizing windings disposed in the slots; and a cylindrical member having a cylindrical shape centered on the rotation axis of the rotor, having radial elasticity and thermal conductivity, the cylindrical member having a refrigerant flow path between its inner and outer peripheral surfaces, and being disposed on the stator core such that its inner peripheral surface is in close contact with the outer peripheral surface of the stator core.

[0008] In one respect, according to this disclosure, the necessity of sealing can be reduced and the need for burning is eliminated, while the stator core can be cooled efficiently. Attached Figure Description

[0009] Figure 1 This is a cross-sectional view that schematically illustrates an example of the cross-sectional structure of the rotary electric motor in this embodiment.

[0010] Figure 2 This is a top view of the stator and housing of a rotating electric motor as seen from the axial direction.

[0011] Figure 3 It is a diagram obtained by unfolding the refrigerant flow path of the flow path forming component circumferentially.

[0012] Figure 4 It is the main sectional view of the flow path forming component, and it is a sectional view obtained using a cutting plane containing the axis of rotation.

[0013] Figure 5 This is a schematic diagram illustrating an example of a cooling system through which the refrigerant flows within the flow path forming member in this embodiment.

[0014] Figure 6 This is a cross-sectional view showing an example of the inlet and outlet in a refrigerant flow path.

[0015] Figure 7 This is an explanatory diagram of a modified rotary electric motor.

[0016] Explanation of reference numerals in the attached figures

[0017] 1... Rotary electrical machine; 10... Motor housing (casing); 30... Rotor; 211... Stator core; 213... Slot; 22... Stator coil (winding); 90... Flow path forming member (cylindrical member); 901... Inner circumferential surface; 902... Outer circumferential surface; 70... Heating element; Δ... Gap. Detailed Implementation

[0018] Hereinafter, each embodiment will be described in detail with reference to the accompanying drawings. It should be noted that the scale of the drawings is merely an example and is not intended to limit the scope of the description. Furthermore, for ease of explanation, shapes and other details in the drawings may be partially exaggerated. Additionally, in the drawings, for ease of observation, for multiple parts with the same properties, only a portion may be labeled with reference to the accompanying drawings.

[0019] Figure 1 This is a cross-sectional view that schematically illustrates an example of the cross-sectional structure of the rotary motor 1 in this embodiment.

[0020] Figure 1 The diagram shows the rotation axis 12 of the rotary electric machine 1. In the following description, axial direction refers to the direction in which the rotation axis (rotation center) 12 of the rotary electric machine 1 extends; axial outer direction refers to the side away from the axial center C0 of the stator core 211; and axial inner direction refers to the side towards the axial center C0 of the stator core 211. Furthermore, radial direction refers to the radial direction centered on the rotation axis 12; radial outer direction refers to the side away from the rotation axis 12; and radial inner direction refers to the side towards the rotation axis 12.

[0021] The rotary motor 1 can also be a vehicle drive motor used, for example, in hybrid vehicles or electric vehicles. However, the rotary motor 1 can also be a rotary motor used for any other purpose.

[0022] The rotary motor 1 is an internal rotor type, and is configured such that the stator 21 surrounds the radially outer side of the rotor 30. The radially outer side of the stator 21 is fixed to the motor housing 10. The stator 21, for example, has a stator core 211 made of stacked steel plates of annular magnetic material, and a plurality of slots 213 for winding the stator coil 22 are formed on the radially inner side of the stator core 211. Alternatively, in a modified example, the stator core 211 may be formed of a pressed powder body made by compressing and solidifying magnetic powder.

[0023] In this embodiment, the stator coil 22 is made of flat wire. Alternatively, the stator coil 22 may be formed of segmented coils that include a U-shape when viewed perpendicular to the axial direction.

[0024] The stator coil 22 includes a slot insertion portion 222 and a coil end 223. The slot insertion portion 222 is inserted into a slot 213 of the stator core 211. The slot insertion portions 222 are disposed in each slot 213. The coil end 223 extends axially outward beyond the axial end face of the stator core 211 and connects the multiple slot insertion portions 222 located in different slots 213.

[0025] The rotor 30 is positioned radially inside the stator 21.

[0026] The rotor 30 includes a rotor core 32, a rotor shaft 34, end plates 35A and 35B, and a magnet 62.

[0027] The rotor core 32 is fixed to the radially outer surface of the rotor shaft 34 and rotates integrally with the rotor shaft 34. The rotor core 32 has a shaft hole 320, in which the rotor shaft 34 is fitted. Alternatively, the rotor core 32 can be fixed to the rotor shaft 34 by burning, pressing, or similar methods. For example, the rotor core 32 can also be joined to the rotor shaft 34 by keying or spline joining. The rotor shaft 34 is supported by the motor housing 10 via bearings 14a and 14b to enable rotation. Furthermore, the rotor shaft 34 defines the rotation axis 12 of the rotary motor 1.

[0028] The rotor core 32 is formed, for example, from a stack of steel plates containing a ring-shaped magnetic material. A magnet 62 is embedded inside the rotor core 32. Specifically, the rotor core 32 has an axially penetrating magnet hole 322, into which a magnet 62 is inserted and fixed. Alternatively, in a modified example, the rotor core 32 may be formed from a compressed and solidified magnetic powder.

[0029] in addition, Figure 1 A rotary motor 1 with a specific construction is shown, but the construction of the rotary motor 1 is not limited to such a specific construction. For example, Figure 1In this design, the rotor shaft 34 is hollow, but it can also be solid. Furthermore, the magnet 62 can be omitted. Alternatively, it can be a rotor with excitation windings.

[0030] The rotary motor 1 of this embodiment features a flow path forming member 90 as its characteristic structure. Hereinafter, it will be discussed in conjunction with... Figure 1 Refer to together Figure 2 The following attached figures will provide a detailed description of the flow path forming component 90 and its associated structures.

[0031] Figure 2 This is a top view of the stator 21 and housing 10 of the rotary motor 1 as seen from the axial direction. Figure 2 For ease of observation, the rotor 30 is omitted from the diagram; only the motor housing 10 is shown with cross-sectional lines. Figure 3 This is a diagram obtained by unfolding the refrigerant flow path 95 of the flow path forming component 90 in the circumferential direction. Figure 4 This is the main sectional view of the flow path forming member 90, and it is a sectional view obtained using a cutting plane passing through the rotation axis 12. Furthermore, Figure 3 The right and left ends are continuous. Figure 3 In the diagram, for ease of observation, a section of the refrigerant flow path 95 is shown using a cross-sectional line.

[0032] In this embodiment, a flow path forming member 90 is provided on the radial outer side of the stator core 211.

[0033] The flow path forming member 90 is cylindrical in shape with the rotation axis 12 as its center. The flow path forming member 90 is elastic, capable of radial expansion and contraction, and has thermal conductivity. For example, the flow path forming member 90 may also be formed from thermoplastic polyurethane elastomer (TPU), ethylene propylene diene monomer (EPDM), silicone rubber, etc. Furthermore, the flow path forming member 90 may also include fillers for improving thermal conductivity.

[0034] The flow path forming member 90 has a refrigerant flow path 95 between its inner peripheral surface 901 and outer peripheral surface 902. That is, the flow path forming member 90 has a refrigerant flow path 95 that is not open in the radial direction. The form of the refrigerant flow path 95 is arbitrary, but it can also be a form in which it is continuously connected in a spiral in the circumferential direction, or a form in which it is reciprocating in the axial direction while being continuous in the circumferential direction. In this embodiment, as... Figure 3 As shown, the refrigerant flow path 95 may also include a plurality of circumferential flow paths 953 arranged side by side in the circumferential direction, starting from the axial flow path 951 with an inlet 9511 and the axial flow path 952 with an outlet 9512 that are adjacent in the circumferential direction.

[0035] The inner peripheral portion 9010 forming the inner peripheral surface 901 has a predetermined thickness and is cylindrical with the rotation axis 12 of the rotor 30 as its center. The outer peripheral portion 9020 forming the outer peripheral surface 902 has a predetermined thickness and is cylindrical with the rotation axis 12 of the rotor 30 as its center. The thicknesses of the inner peripheral portion 9010 and the outer peripheral portion 9020 can also be the same.

[0036] The flow path forming member 90 has a partition 9030 extending radially and circumferentially between the inner peripheral portion 9010 and the outer peripheral portion 9020. The partition 9030 separates two circumferential flow paths 953 that are adjacent in the axial direction among the plurality of circumferential flow paths 953.

[0037] The fluid circulating in the refrigerant flow path 95 is cooling water, but in a modified example, it may be other liquids (such as oil) or gases.

[0038] The flow path forming member 90 is disposed on the stator core 211 such that its inner circumferential surface 901 is in close contact with the outer circumferential surface of the stator core 211. Specifically, the flow path forming member 90 is installed on the stator core 211 with an inner diameter larger than that before assembly. The flow path forming member 90 can elastically deform by increasing its inner diameter (diameter expansion), thereby improving the tightness of contact with the stator core 211. If the tightness of contact between the flow path forming member 90 and the stator core 211 is increased, the thermal conductivity between the flow path forming member 90 and the stator core 211 is increased. That is, the thermal resistance between the flow path forming member 90 and the stator core 211 is reduced. As a result, the stator core 211 can be efficiently cooled by the cooling water in the refrigerant flow path 95.

[0039] For the flow path forming member 90, the inner circumferential surface 901 can be directly attached to the outer circumferential surface of the stator core 211, or the inner circumferential surface 901 can be sandwiched with a high thermal conductivity grease and attached to the outer circumferential surface of the stator core 211. This sandwiching of a high thermal conductivity grease is preferred when the stator core 211 is formed of an electromagnetic steel plate. This is because: since the surface of the electromagnetic steel plate is rough (due to the presence of minute bumps and depressions), applying grease smooths the surface, thereby improving thermal conductivity.

[0040] like Figure 1 As shown, the flow path forming member 90 is preferably arranged across the entire axial length of the stator core 211. This allows for efficient cooling across the entire axial length of the stator core 211.

[0041] Flow path forming component 90 is preferably as follows Figure 2 As shown, the inner circumferential surface 901 is disposed on the stator core 211 in such a way that it is tightly attached to the outer circumferential surface of the stator core 211 along the entire circumference of the stator core 211.

[0042] Thus, the flow path forming member 90 of this embodiment has a refrigerant flow path 95 inside, thereby substantially eliminating the need for sealing. Furthermore, although it is secured to the stator core 211 by elastic deformation, it does not subject the stator core 211 to stress as is seen in cases of burn-in. Therefore, according to this embodiment, the need for sealing is reduced, burn-in is eliminated, and the stator core 211 is cooled efficiently.

[0043] However, in stator core 211, bolt BT (see reference) Figure 1 In the structure that is fastened to the motor housing 10, at the part through which the bolt BT passes (hereinafter referred to as "ear 214"), the outer peripheral shape of the stator core 211 protrudes radially outward in a convex shape. Therefore, due to such an ear 214, it may be difficult for the inner peripheral surface 901 of the flow path forming member 90 to adhere tightly to the outer peripheral surface of the stator core 211.

[0044] Taking this into consideration, such as Figure 2 As shown, the stator core 211 preferably has a longer variation range from the lug 214 to the general outer periphery. That is, the change in outer diameter is made more gradual. For example, the circumferential length of the variation range can also be greater than the circumferential length of the bolt BT range. As a result, the possibility of reduced tightness between the inner circumferential surface 901 of the flow path forming member 90 and the outer circumferential surface of the stator core 211 due to the lug 214 can be reduced.

[0045] Additionally, in this embodiment, as Figure 4 As shown, the refrigerant flow path 95 has a rectangular cross-section with the same cross-sectional area at each position in the axial direction, but it can also be a rectangle with different cross-sectional areas. Furthermore, in this embodiment, the cross-section of the refrigerant flow path 95 is rectangular, but it can also be other shapes such as circles. However, when the cross-section is rectangular, the axial section where the radial thickness of the inner periphery 9010 can be relatively thin can be relatively long, thus effectively improving the cooling capacity.

[0046] In this embodiment, the inner peripheral portion 9010, the outer peripheral portion 9020, and the partition portion 9030 of the flow path forming member 90 can be formed from the same material, or they can be formed from different materials. For example, the inner peripheral portion 9010, the outer peripheral portion 9020, and the partition portion 9030 can be formed such that the hardness of the partition portion 9030 is intentionally higher than that of the inner peripheral portion 9010 and the outer peripheral portion 9020. By increasing the hardness of the partition portion 9030, the refrigerant flow path 95 will not collapse in the assembled state (elastic deformation state) of the flow path forming member 90, ensuring the desired cross-sectional area. In addition, the partition portion 9030 is less likely to tilt relative to the radial direction, improving shape stability. Furthermore, by making the hardness of the inner peripheral portion 9010 and the outer peripheral portion 9020 relatively low, the conformability can be improved, and the tightness between the flow path forming member 90 and the stator core 211 can be improved.

[0047] In this embodiment, the hardness of the flow path forming member 90 is preferably 20 to 80 Shore hardness, more preferably 40 to 70 Shore hardness. This prevents the refrigerant flow path 95 from collapsing and improves the following of the stator core 211.

[0048] Figure 5 This is a schematic diagram showing an example of a cooling system 300 through which the refrigerant flow path 95 within the flow path forming member 90 of this embodiment passes. Figure 5 The flow pattern of cooling water is schematically shown using arrows such as R361. Figure 6 This is a cross-sectional view showing an example of inlet 9511 and outlet 9512.

[0049] Figure 5 In this process, cooling water supplied by water pump 810 passes through radiator 820. In radiator 820, the cooling water is cooled by heat exchange with the outside air. The cooled water, after passing through radiator 820, flows through supply path 328 and toward refrigerant path 95 (refer to arrow R361). The cooling water supplied from inlet 9511 to refrigerant path 95 cools the stator core 211 as it flows through refrigerant path 95 until it is discharged from outlet 9512 (refer to arrow R371). Additionally, as... Figure 6 As shown, the refrigerant flow path 95 may also have an inlet 9511 at one end of the axial direction and an outlet 9512 at the other end of the axial direction. Furthermore, the cooling water that has cooled the stator core 211 is introduced from the outlet 9512 of the refrigerant flow path 95 into the outlet flow path 331 on the outlet side (refer to arrow R381), and then returns to the water pump 810 after passing through the heated object 80 (refer to arrow R390). Additionally, Figure 5In this configuration, the water pump 810 is positioned between the outlet flow path 331 and the radiator 820. Alternatively, the outlet flow path 331 can be connected to the radiator 820, and the water pump 810 can be positioned between the radiator 820 and the supply flow path 328. Furthermore, the supply flow path 328 and / or the outlet flow path 331 may be partially or entirely formed of a material different from the material of the flow path forming member 90 (e.g., metal).

[0050] exist Figure 5 In the example shown, the object to be heated 80 can be any object, but it could also be, for example, the high-voltage battery used as a power source for the rotary motor 1. Therefore, even when the high-voltage battery is very cold due to prolonged parking or other vehicle-stopping conditions in low-temperature environments, its temperature can be rapidly and appropriately increased, thereby improving the battery's characteristics when the vehicle is in motion.

[0051] In addition, in this embodiment, the purpose of utilizing the heat generated by the rotary motor 1 is to heat the high-voltage battery, but it can also serve other purposes, or even purposes other than that. For example, the purpose of utilizing the heat generated by the rotary motor 1 can also include heating the oil itself. That is, the object 80 to be heated can also be the oil itself.

[0052] In addition, Figure 5 In the example shown, the oil introduced into the outlet flow path 331 must pass through the heated object 80 and return to the water pump 810, but the flow path can also be reversed via a valve or the like. In this case, the oil introduced into the outlet flow path 331 may pass through the heated object 80 and return to the water pump 810 only when the temperature of the heated object 80 is below a lower limit.

[0053] However, in order for the heat taken away from the stator 21 to be efficiently transferred to the object to be heated 80 via the cooling water in the refrigerant flow path 95, it is necessary to prevent the heat of the cooling water in the refrigerant flow path 95 from being taken away by other non-heated objects.

[0054] Therefore, in this embodiment, as Figure 1 As shown, the flow path forming member 90 has a gap Δ relative to the motor housing 10. That is, the flow path forming member 90 does not directly abut against the motor housing 10 in the radial direction. This prevents the heat of the cooling water inside the flow path forming member 90 from being taken away by the motor housing 10. This effect is significant because the motor housing 10 has a relatively large volume (heat capacity).

[0055] Figure 7 This is an explanatory diagram of a modified rotary motor 1A. Figure 7 The diagram of rotor 30 is omitted in the text.

[0056] The rotary motor 1A differs in that the outer periphery of the stator core 211A is polygonal. Consequently, when viewed axially, the shape of the flow path forming member 90 is also polygonal. Thus, the outer periphery of the stator core 211A is arbitrary, as long as it is a shape easily followed by the flow path forming member 90.

[0057] Furthermore, in this modified example, the outer peripheral surface 902 of the flow path forming member 90 also includes a heating element 70 for controlling the energization of the stator coil 22. The heating element 70 can also be a component constituting an inverter (not shown) electrically connected to the stator coil 22. In this case, the heating element 70 can also be a switching element such as a MOSFET (metal-oxide-semiconductor field-effect transistor) or an IGBT (Insulated Gate Bipolar Transistor). Additionally, the heating element 70 can also include a smoothing capacitor located between the inverter (not shown) and the high-voltage battery (not shown). The heating element 70 can also be in the form of a module or mounted on a substrate. In this embodiment, the outer peripheral surface 902 of the flow path forming member 90 is planar, therefore, the mounting of the heating element 70 is easier.

[0058] According to this variation, the heating element 70 can also be efficiently cooled by the cooling water within the flow path forming member 90. Furthermore, the heating element 70 can be positioned using the radial gap Δ between the flow path forming member 90 and the motor housing 10, achieving efficient space utilization. Alternatively, even when the heating element 70 is positioned, a radial gap (not shown) can still be maintained between the heating element 70 and the motor housing 10, or the gap Δ can be filled by the heating element 70.

[0059] The embodiments have been described in detail above, but are not limited to specific embodiments. Various modifications and alterations can be made within the scope of the claims. Furthermore, all or more of the structural elements of the foregoing embodiments can be combined.

[0060] For example, in the above embodiment, the flow path forming member 90 is a single member integrally surrounding the stator core 211 along its axial direction, but it can also be axially segmented. That is, multiple flow path forming members 90 can be axially connected, integrally surrounding the stator core 211 along its axial direction. In this case, the refrigerant flow paths 95 within each flow path forming member 90 can also be non-communicating with each other around the stator core 211, and can each have an inlet 9511 and an outlet 9512. In this case, it is also possible to arrange the refrigerant flow paths 95 around the stator core 211 using multiple flow path forming members 90 without increasing the necessity of sealing.

Claims

1. A rotary electric motor, characterized in that, have: Rotor; A stator core having slots, and energizing windings disposed in the slots; and A cylindrical component, which is cylindrical in shape centered on the rotation axis of the rotor, and has the elasticity to expand and contract radially and is thermally conductive. The cylindrical member has a refrigerant flow path between its inner and outer circumferential surfaces, and is disposed on the stator core with its inner circumferential surface in close contact with the outer circumferential surface of the stator core.

2. The rotary motor according to claim 1, characterized in that, It also includes a housing that houses the rotor, the stator core, and the cylindrical member. The housing is radially spaced apart from the outer periphery of the cylindrical member.

3. The rotary motor according to claim 1 or 2, characterized in that, The outer peripheral surface of the cylindrical member also has a heating element for controlling the energization of the winding.

4. The rotary electric motor according to any one of claims 1 to 3, characterized in that, The cylindrical member has an inner circumferential surface that is integrally formed and closely adheres to the outer circumferential surface of the stator core.

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