Motor for electric compressor and electric compressor

Abstract

[Problem] To provide a motor for an electric compressor, the motor such that a stator is fixed to a housing without using shrink-fitting. [Solution] Provided is a motor for an electric compressor, the motor including a housing and a stator. The stator includes a core divided into an inner core and an outer core. The inner core is press-fitted to the inside of the outer core and fixed, and the outer core is insert-molded at the inner diameter of the housing.

Description

Electric compressor motor and electric compressor

[0001] The present invention relates to a motor for an electric compressor and an electric compressor.

[0002] Conventionally, there has been known an electric compressor in which a stator is fixed inside a casing (the inner diameter of the housing) by shrink fitting. The electric compressor is used to compress refrigerant in an air conditioner for a vehicle, and is integrated with a compression mechanism and an electric motor that drives the compression mechanism (see Patent Document 1 below). The housing is cast from aluminum to reduce weight.

[0003] JP 2016-011610 A

[0004] When fixing a stator to the inner diameter of a housing by shrink fitting, the housing is heated to expand the inner diameter, and the stator is inserted into the inner diameter of the housing and then cooled to shrink the inner diameter, thereby fixing the stator to the housing.

[0005] However, when fixing a stator to a housing by shrink fitting, it is necessary to perform cutting on the inner diameter of the housing in order to increase the positional accuracy between the housing and the stator, but this cutting process has the problem of cutting away the dense layer on the surface.In addition, when the housing is cooled to reduce its inner diameter, the outer core of the stator, which comes into contact with the inner diameter of the housing, causes deformation of the housing.

[0006] The present invention has been proposed to address these circumstances, and has an object to provide a motor for an electric compressor in which a stator is fixed to a housing without using shrink fitting.

[0007] In order to solve such problems, the motor for an electric compressor according to the present invention comprises a housing and a stator, the stator being composed of a core divided into an inner core and an outer core, the inner core being pressed into and fixed inside the outer core, and the outer core being insert-molded into the inner diameter of the housing.

[0008] With these features, the present invention can provide a motor for an electric compressor in which the stator is fixed to the housing without using shrink fitting.

[0009] 1 is a cross-sectional view of an electric compressor according to an embodiment of the present invention; 2 is an exploded perspective view of a motor for an electric compressor according to an embodiment of the present invention; 3 is a diagram of an inner core of a stator according to an embodiment of the present invention; 4 is a top view of a motor for an electric compressor according to an embodiment of the present invention; 5 is a cross-sectional view of the motor for an electric compressor of FIG.

[0010] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the following description, the same reference numerals indicate parts with the same functions, and duplicated explanations in each drawing will be omitted as appropriate. Furthermore, each drawing shows one embodiment of the present invention, and is not intended to limit the present invention.

[0011] The electric compressor motor 10 of the present invention is provided in the electric compressor 1 of a vehicle air conditioner. The shaft of the electric compressor motor 10 is indicated by a dashed line C in Fig. 1, and in the following description, the axial direction of the electric compressor motor 10 refers to the direction along the dashed line C in Fig. 1.

[0012] First, an electric compressor 1 will be described using Figure 1. The electric compressor 1 according to this embodiment is provided in a refrigerant circuit of, for example, a vehicle air conditioner, and draws in, compresses, and discharges refrigerant from the vehicle air conditioner. As shown in Figure 1, the electric compressor 1 includes an electric compressor motor 10, a compression mechanism 30 driven by the electric compressor motor 10, an inverter 40 for driving the electric compressor motor 10, and a housing 20 that accommodates the electric compressor motor 10, the compression mechanism 30, and the inverter 40.

[0013] 1, the electric compressor 1 is a so-called inverter-integrated compressor, and includes a first housing 21 that houses the electric compressor motor 10 and the inverter 40 therein, a second housing 22 that houses the compression mechanism 30 therein, a compression mechanism cover 23, and an inverter cover 24. These housings and covers (21, 22, 23, 24) are fastened together by fastening means (not shown) such as bolts to form a housing 20 of the electric compressor 1.

[0014] As shown in Fig. 1, the electric compressor motor 10 includes a rotor 14 having a plurality of magnetic poles (not shown), an annular stator 11 disposed radially outward of the rotor 14, an electrically insulating bobbin 15 (see Fig. 2) provided on the stator 11, a coil 16 (see Fig. 2) wound around the bobbin 15, and a first housing 21 that accommodates these components. For example, a three-phase AC motor is used. For example, DC current from a vehicle battery (not shown) is converted to AC current by an inverter 40 and supplied to the electric compressor motor 10. The rotor 14 has, for example, four N-pole permanent magnets and four S-pole permanent magnets embedded therein, resulting in eight equally spaced magnetic poles.

[0015] The stator 11 of the electric compressor motor 10 is composed of two split cores: an outer core 12 and an inner core 13. The outer core 12 of the stator 11 is insert-molded into the inner diameter of the annular inner wall 211 (see FIG. 2 ) of the first housing 21, and the inner diameter of the first housing 21 and the outer core 12 are integrated. The stator is fixed to the first housing 21 by fixing the inner core 13 to the outer core 12.

[0016] Although not shown, the housing 20 is formed with a suction port and a discharge port for the refrigerant, and for example, the refrigerant drawn in through the suction port flows through the first housing 21 and is then drawn into the second housing 22. The electric compressor motor 10 is cooled by the drawn refrigerant.

[0017] The compression mechanism 30 is driven by the electric compressor motor 10 to compress the refrigerant, and is housed in the second housing 22 and disposed on the opposite side of the rotor 14 from the inverter 40. In this embodiment, the compression mechanism 30 is a scroll compressor and includes a fixed scroll 31 and a movable scroll 32. The movable scroll 32 is driven to orbit relative to the fixed scroll 31, thereby compressing the refrigerant. The refrigerant compressed by the compression mechanism 30 is discharged from a discharge port.

[0018] Next, the fixation of the first housing 21 and the stator 11 of the electric compressor motor 10 in this embodiment will be described using Figures 2 to 4. Figure 2 illustrates the inner diameter portion of the first housing 21 and the stator 11, and does not illustrate other parts around the outer diameter side of the first housing 21. Furthermore, the electric compressor motor 10 includes the rotor 14 on the inner diameter side of the stator 11 as shown in Figure 1, but the rotor 14 is not illustrated in Figure 2.

[0019] The stator 11 is composed of two annular cores, an outer core 12 and an inner core 13, and the outer core 12 of the stator 11 is insert-molded into the inner diameter of a first housing 21 to form an integrated unit. The first housing 21 is cast from aluminum, and the outer core 12 is insert-molded into the inner diameter of an annular inner wall 211 of the first housing 21 when the first housing 21 is cast. The outer core 12 is made of iron, which has a higher melting point than aluminum, so there is no risk of the outer core 12 being deformed by the high-temperature aluminum during insert molding.

[0020] 2 and 3, the inner core 13 of the annular stator 11 has a plurality of protrusions 131 extending radially outward. An electrically insulating bobbin 15 is provided on each protrusion 131, and a copper wire is wound around the bobbin 15 to form a coil 16. A shaft hole 151 of the bobbin 15 is elongated in the axial direction of the electric compressor motor 10 to match the shape of the protrusions 131.

[0021] The protruding portion 131 passes through the axial hole 151 of the bobbin 15, and its tip is exposed from the axial hole 151 to the outer diameter side of the inner core 13. The tip portion of the protruding portion 131 that is exposed from the axial hole 151 of the bobbin 15 to the outer diameter side of the inner core 13 becomes a convex portion 132. In FIG. 2 , the part of the protruding portion 131 other than the convex portion 132 at the tip is hidden by the bobbin 15 and cannot be seen.

[0022] A plurality of recesses 121 are formed on the inner diameter side of the outer core 12, and a plurality of protrusions 132 corresponding to the shapes of the recesses 121 of the outer core 12 are formed at the tips of protrusions 131 on the outer diameter side of the inner core 13. When the inner core 13 is press-fitted into the outer core 12, the protrusions 132 of the inner core 13 are press-fitted so as to fit into the recesses 121 of the outer core 12.

[0023] 4 shows a state in which the inner core 13 is press-fitted into the outer core 12 and the stator 11 is fixed to the first housing 21. The rotor 14 is also omitted from Fig. 4. As shown in Fig. 4, the protrusions 132 of the inner core 13 of the stator 11 are fitted into the recesses 121 of the outer core 12, and the stator 11 is fixed to the first housing 21.

[0024] As described above, in the electric compressor motor 10 of this embodiment, the outer core 12 of the stator 11 is insert-molded into the inner diameter of the first housing 21, and after the first housing 21 has cooled, the inner core 13 is press-fitted into the inside of the outer core 12, thereby fixing the first housing 21 and the stator 11 together. This method makes it possible to fix the first housing 21 and the stator 11 together without using shrink fitting.

[0025] Unlike motors for electric compressors in which the first housing 21 and the stator 11 are fixed by shrink fitting, the motor 10 for electric compressors of this embodiment does not require cutting of the inner diameter of the first housing 21 when fixing the stator 11 to the first housing 21. This prevents cutting of the high-density aluminum layer on the surface of the inner diameter of the first housing 21, preventing problems such as porosity being exposed on the surface of the inner diameter of the first housing 21 and refrigerant leaking into the porosity, for example.

[0026] Furthermore, in the motor 10 for an electric compressor according to this embodiment, the first housing 21 and the stator 11 are fixed together by press-fitting after the first housing 21, i.e., the aluminum, has cooled. This prevents the stator 11 from unintentionally deforming the first housing 21 when the first housing 21 and the stator 11 are fixed together.

[0027] Next, modified examples of the electric compressor motor 10 will be described with reference to Figures 5 and 6. The electric compressor motor 10 in the modified examples shown in Figures 5 and 6 is similar to the electric compressor motor 10 shown in Figures 1 to 4 unless otherwise noted.

[0028] 5, similar to Fig. 4, shows a state in which the inner core 13 is press-fitted into the outer core 12 and the stator 11 is fixed to the first housing 21. As shown in Fig. 5, in this modification, a flow passage 212 is formed in an inner wall 211A of the first housing 21 along the axial direction of the electric compressor motor 10. Cooling water for cooling the electric compressor motor 10 can flow through the flow passage 212.

[0029] FIG. 6 is an enlarged cross-sectional view of the first housing 21 and the stator 11 shown in FIG. 5 taken along line A-A. FIG. 6 illustrates an enlarged view of the contact portion between the first housing 21 and the stator 11. As shown in the cross-sectional view of FIG. 6, the electric compressor motor 10 of this embodiment is integrated with the inner diameter of the first housing 21 by insert molding the outer core 12 of the stator 11. As a result, no gap is created at the contact surface between the first housing 21 and the stator 11 when the first housing 21 and the stator 11 are fixed together. This reduces heat dissipation resistance between the first housing 21 and the stator 11, allowing the electric compressor motor 10 to be efficiently cooled by the coolant passing through the flow passage 212.

[0030] Furthermore, the heat obtained by cooling the electric compressor motor 10 may be used to regulate the temperature of a battery installed in the vehicle or as a heat source for air conditioning in an air conditioner. The flow passage 212 may include a flow passage along, for example, a refrigerant circuit or a heat medium circuit provided in an air conditioner in a flow passage other than the inner wall 211A of the first housing 21, and may be a circulation flow passage for circulating coolant using a pump or the like. The coolant flowing through the flow passage 212 may be configured to be able to exchange heat with the refrigerant in the refrigerant circuit or the heat medium in the heat medium circuit, and the heat may be used to regulate the temperature of the battery or for air conditioning.

[0031] As described above, the electric compressor motor 10 of the present invention includes a housing 20 (first housing 21) and a stator 11. The stator 11 is composed of a core divided into an inner core 13 and an outer core 12. The inner core 13 is press-fitted and fixed inside the outer core 12, and the outer core 12 is insert-molded into the inner diameter of the housing 20 (first housing 21). In this electric compressor motor 10, the stator 11 is accurately fixed to the housing 20 (first housing 21) without cutting the inner diameter of the housing 20 (first housing 21). Because the high-density aluminum layer on the inner diameter surface of the housing 20 (first housing 21) is not cut, problems such as porosity being exposed on the inner diameter surface of the first housing 21 and refrigerant leaking through the porosity can be prevented. Furthermore, unlike shrink fitting, problems such as deformation of the housing 20 when fixing the housing 20 and the stator 11 can be prevented.

[0032] In the electric compressor motor 10 of the present invention, the housing 20 (first housing 21) has an inner wall 211A provided with a flow passage 212 through which cooling water passes. In this electric compressor motor 10, the heat dissipation resistance between the housing 20 and the stator 11 is low, so that the electric compressor motor 10 can be efficiently cooled by the cooling water passing through the flow passage 212.

[0033] The embodiments of the present invention have been described above in detail with reference to the drawings. However, the specific configuration is not limited to the described embodiments, and the present invention also includes design changes and the like within the scope of the present invention that do not deviate from the gist of the present invention.

[0034] 1: electric compressor, 10: motor for electric compressor, 11: stator, 12: outer core, 13: inner core, 14: rotor, 15: bobbin, 16: coil, 20: housing, 21: first housing, 22: second housing, 23: compression mechanism cover, 24: inverter cover, 30: compression mechanism, 31: fixed scroll, 32: movable scroll, 40: inverter, 121: recess, 131: protrusion, 132: convex portion, 151: shaft hole, 211, 211A: inner wall, 212: flow passage, C: dashed dotted line

Claims

1. A motor for an electric compressor, comprising: a housing; and a stator; the stator is composed of a core divided into an inner core and an outer core; the inner core is press-fitted and fixed inside the outer core; and the outer core is insert-molded into the inner diameter of the housing.

2. The motor for an electric compressor according to claim 1, wherein the housing has an inner wall provided with a flow passage through which cooling water passes.

3. An electric compressor equipped with the motor for an electric compressor according to claim 1.

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