Inverter-integrated electric compressor and method for manufacturing same

Abstract

[Problem] To provide an inverter-integrated electric compressor with which vibration and noise due to resonance can be suppressed and high-voltage electric components can be avoided without any trouble, while the weight and production cost of a cover for closing an inverter-accommodating part are reduced. [Solution] This inverter-integrated electric compressor is provided with a cover 15 for closing an inverter-accommodating part 13. The cover 15 is made from sheet metal comprising: an upper wall part 41; a longitudinal wall part 42 formed continuously with the outer periphery of the upper wall part; and a seal flange part 46 that projects outward continuously from the outer periphery of the longitudinal wall part, and that is attached to a housing 11. The upper wall part 41 is constituted of a flat surface 61 and a curved surface 63 lowered in the outer peripheral direction continuously from the flat surface.

Description

Inverter-integrated electric compressor and its manufacturing method

[0001] The present invention relates to an inverter-integrated electric compressor having a cover that closes an inverter accommodating section formed in a housing, and a method for manufacturing the same.

[0002] Conventionally, in this type of inverter-integrated electric compressor, particularly an electric compressor that constitutes a vehicle air conditioning system, the inverter is housed and fixed in an inverter housing (inverter case) formed in a metal housing, and this inverter housing is then closed with a cover. Here, the cover does not need to be pressure-resistant, so it is usually made of a thin aluminum die-cast plate, but when vibrations from the compression mechanism and motor inside the housing are transmitted to the cover, it vibrates and generates noise.

[0003] In this case, if the frequency of the vibratory force of the compression mechanism or motor matches or is close to the natural frequency (eigenvalue) of the cover, resonance occurs, resulting in increased vibration and noise. To address this issue, electric compressors have been proposed in which grooves are formed in the cover to shift the natural frequency of the cover away from the resonance (see, for example, Patent Document 1).

[0004] Patent No. 5510490 Patent No. 6948112

[0005] However, creating a shape like that of Patent Document 1 using aluminum die casting makes it difficult to reduce weight, and increasing the thickness results in a larger height, making it difficult to achieve a compact design. Furthermore, with aluminum die casting, after casting (die casting) from an aluminum ingot, numerous processes are required, such as heat treatment to remove distortion and cutting, which increases carbon dioxide emissions and makes it difficult to achieve carbon neutrality. Furthermore, the configuration of Patent Document 1 has issues, such as not being able to shift the natural frequency in a lower direction.

[0006] Therefore, although not for the inverter accommodating portion cover, it is conceivable to avoid resonance by increasing the natural frequency by using a curved surface for the cover, as described in Patent Document 2, for example. However, if the entire upper wall of the cover is made of a curved surface, the cover will be close to the electrical components that make up the inverter near the outer edge, which poses a problem in that it cannot be used in electric compressors, which require higher voltages these days, in order to ensure an insulating distance from the high-voltage electrical components.

[0007] The present invention has been made to solve the above-mentioned conventional technical problems, and aims to provide an inverter-integrated electric compressor that can reduce the weight and production costs of the cover that closes the inverter accommodating section, while suppressing vibration and noise caused by resonance and avoiding high-voltage electrical components without causing any problems, and a manufacturing method thereof.

[0008] The inverter-integrated electric compressor of the present invention comprises a metal housing in which a motor and a compression mechanism are built, an inverter for driving the motor, an inverter accommodating section formed in the housing and accommodating the inverter, and a metal cover for closing the inverter accommodating section, wherein the cover is made of sheet metal having an upper wall section, a vertical wall section formed continuous with the outer periphery of the upper wall section, and a seal flange section that protrudes outward continuous with the outer periphery of the vertical wall section and is attached to the housing, and wherein the upper wall section is composed of a flat surface and a curved surface that is continuous with the flat surface and descends toward the outer periphery.

[0009] The inverter-integrated electric compressor of the invention of claim 2 is characterized in that in the above invention, the natural frequency of the cover is increased by adjusting the radius of curvature of the curved surface of the upper wall portion and / or the angle at which the vertical wall portion rises from the seal flange portion.

[0010] The inverter-integrated electric compressor according to the invention of claim 3 is characterized in that in the above invention, the radius of curvature of the curved surface of the upper wall portion is set to different values ​​in the longitudinal direction and the lateral direction of the cover.

[0011] The inverter-integrated electric compressor of the invention of claim 4 is characterized in that in the invention of claim 1, the inverter has a plurality of electrical components, and the flat surface of the upper wall portion is formed in a position corresponding to a high-voltage electrical component that has a higher voltage than the other electrical components.

[0012] The inverter-integrated electric compressor of the invention of claim 5 is characterized in that in the above invention, the high-voltage electrical components are arranged on the outer edge of the inverter accommodating section, and the angle at which the vertical wall portion rises from the seal flange portion at the position corresponding to the high-voltage electrical components is larger than the angle at other positions.

[0013] The inverter-integrated electric compressor of the invention of claim 6 is characterized in that in the invention of claim 1, the vicinity of the connection between the flat surface and the curved surface of the upper wall portion corresponds to an electrical component whose dimension in the cover direction is larger than that of other electrical components.

[0014] The inverter-integrated electric compressor of the invention of claim 7 is characterized in that, in the inventions of claims 4 to 6, the cover has a recess formed in the upper wall portion and protruding toward the housing, and this recess abuts against the electrical component directly or via a heat dissipation material.

[0015] A manufacturing method for an inverter-integrated electric compressor according to the invention of claim 8 is characterized in that, in manufacturing an inverter-integrated electric compressor comprising a metal housing incorporating a motor and a compression mechanism, an inverter for driving the motor, an inverter accommodating section formed in the housing and accommodating the inverter, and a metal cover for closing the inverter accommodating section, the cover is made of sheet metal having an upper wall section, a vertical wall section formed continuous with the outer periphery of the upper wall section, and a seal flange section that protrudes outward continuous with the outer periphery of the vertical wall section and is attached to the housing, and the natural frequency of the cover is increased by adjusting the radius of curvature of the curved surface of the upper wall section and / or the angle at which the vertical wall section rises from the seal flange section.

[0016] According to the present invention, in an inverter-integrated electric compressor comprising a metal housing incorporating a motor and a compression mechanism, an inverter for driving the motor, an inverter accommodating section configured in the housing and accommodating the inverter, and a metal cover closing the inverter accommodating section, the cover is formed from sheet metal having an upper wall section, a vertical wall section formed continuous with the outer periphery of the upper wall section, and a seal flange section that continues from the outer periphery of the vertical wall section and is attached to the housing, and the upper wall section is composed of a flat surface and a curved surface that continues from this flat surface and becomes lower in the outer periphery.Therefore, for example, as in the invention of claim 4, by forming the flat surface of the upper wall section in a position corresponding to a high-voltage electrical component that operates at a higher voltage than other electrical components of the inverter, it is possible to avoid the high-voltage electrical components and ensure an insulation distance between the upper wall section and the high-voltage electrical component without hindrance.

[0017] This is particularly effective when high-voltage electrical components are arranged on the outer edge of the inverter accommodating section, as in the invention of claim 5. Furthermore, by making the angle at which the vertical wall portion rises from the seal flange portion at the position corresponding to the high-voltage electrical component larger than the angle at other positions, it is possible to ensure an insulating distance between the vertical wall portion and the high-voltage electrical component.

[0018] Furthermore, as in the invention of claim 6, by accommodating the vicinity of the connection between the flat surface and the curved surface of the upper wall portion with an electrical component whose dimension in the cover direction is larger than other electrical components, it is possible to minimize the dimension by which the cover protrudes from the housing while avoiding interference between the cover and the electrical component.

[0019] As in the inventions of claims 2 and 8, by adjusting the radius of curvature of the curved surface of the upper wall portion and / or the angle at which the vertical wall portion rises from the seal flange portion, the natural frequency of the cover can be increased, thereby suppressing the problem of the cover resonating with vibrations from the compression mechanism or motor, and thereby making it possible to significantly reduce vibrations and noise caused by resonance.

[0020] In this case, by making the radius of curvature of the curved surface of the upper wall portion different in the longitudinal direction and the lateral direction of the cover as in the invention of claim 3, it is possible to expand the adjustment range of the natural frequency of the cover.

[0021] Furthermore, because the cover is made of sheet metal, it can be manufactured by pressing steel plate compared to aluminum die casting, which reduces the number of processes and saves energy, thereby significantly reducing carbon dioxide emissions, contributing to environmental issues and reducing production costs. Furthermore, in the present invention, sheet metal with a substantially uniform thickness is formed to increase the natural frequency, thereby reducing weight and, when used in a vehicle air conditioning system, improving the performance of the vehicle. Furthermore, by forming the upper wall portion of the sheet metal cover with flat and curved surfaces and forming vertical walls around its periphery, the strength of the cover itself is also improved.

[0022] Furthermore, as in the seventh aspect of the present invention, a recess that protrudes toward the housing is formed in the upper wall of the cover, and this recess is brought into contact with the electrical components directly or via a heat dissipating material, so that heat generated by the electrical components can be transferred to the cover directly or via the heat dissipating material, thereby enabling the electrical components in the inverter accommodating section to be cooled using the cover.

[0023] Fig. 4 is a schematic cross-sectional view of an inverter-integrated electric compressor according to an embodiment of the present invention. Fig. 5 is a perspective view of a cover that closes an inverter accommodating section of the electric compressor of Fig. 1, as seen from the outside. Fig. 6 is a perspective view of the cover of Fig. 2, as seen from the inside. Fig. 7 is a plan view of the cover of Fig. 2. Fig. 8 is a cross-sectional view of the cover of Fig. 4, taken along line A-A. Fig. 9 is a cross-sectional view of the cover of Fig. 4, taken along line B-B. Fig. 10 is a cross-sectional view of the cover of Fig. 4, taken along line C-C. Fig. 11 is a cross-sectional view of the cover of Fig. 4, taken along line D-D.

[0024] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Fig. 1 is a schematic cross-sectional view of an inverter-integrated electric compressor 1 according to one embodiment of the present invention. The electric compressor (inverter-integrated electric compressor) 1 according to the present embodiment is used in a refrigerant circuit constituting an air conditioning system for an electric vehicle, for example, and draws in a refrigerant as a working fluid for the air conditioning system, compresses it, and discharges it into a discharge pipe. The electric compressor is a so-called horizontally-mounted inverter-integrated scroll electric compressor that includes a three-phase electric motor 2 as the motor of the present invention, an inverter 3 for operating the electric motor 2, and a scroll compression mechanism 4 as a compression mechanism driven by the electric motor 2.

[0025] In this embodiment, the electric compressor 1 includes a cylindrical stator housing 7 that houses the electric motor 2 and center plate 6 inside, an inverter case 8 that is attached to an end wall on one end of the stator housing 7 and houses the inverter 3 inside, and a rear casing 9 that is attached to the open end face on the other end of the stator housing 7.

[0026] The stator housing 7, inverter case 8, and rear casing 9 are all made of metal (in this embodiment, made of aluminum, except for the cover 15 described later), and are joined together to form the housing 11 of the electric compressor 1 in this embodiment.

[0027] A motor chamber 12 that houses the electric motor 2 is defined within the stator housing 7, and one end face of the motor chamber 12 is basically closed by the end wall of the stator housing 7. The other end face of the motor chamber 12 of the stator housing 7 is open, and the electric motor 2 is accommodated in the motor chamber 12 through this opening, and then the center plate 6 is accommodated through the same opening. In addition, an auxiliary bearing 16 is attached to the inner surface (on the motor chamber 12 side) of the end wall of the stator housing 7 to rotatably support one end of a drive shaft 14 of the electric motor 2.

[0028] The center plate 6 has an opening on the side opposite the electric motor 2 (the other end), and after the movable scroll 22 of the scroll compression mechanism 4 is accommodated in this opening, the rear casing 9 to which the fixed scroll 21 of the scroll compression mechanism 4 is fixed is fixed to the opening of the stator housing 7, thereby closing the opening.

[0029] The center plate 6 also has a through hole 17 through which the other end of the drive shaft 14 of the electric motor 2 is inserted, and a main bearing 18 is attached to the center plate 6 on the scroll compression mechanism 4 side of this through hole 17 to rotatably support the other end of the drive shaft 14 on the scroll compression mechanism 4 side.

[0030] The electric motor 2 is composed of a stator 25, which has a coil wound thereon and is fixed to the inside of the peripheral wall of a stator housing 7, and a rotor 35 that rotates inside the stator 25. For example, direct current from a vehicle battery (not shown) is converted to three-phase alternating current by an inverter 3, and this current is supplied to the coil of the stator 25 of the electric motor 2, thereby driving and rotating the rotor 35. The drive shaft 14 is fixed to the rotor 35.

[0031] A suction port 30 is formed in the stator housing 7, and refrigerant drawn in from the suction port 30 passes through the motor chamber 12 of the stator housing 7, flows into the center plate 6, and is drawn into a suction section 37 on the outside of the scroll compression mechanism 4. This cools the electric motor 2 with the drawn refrigerant. The refrigerant compressed in the scroll compression mechanism 4 is discharged from a discharge chamber 27 (described later) through a discharge port 20 formed in the rear casing 9 into a discharge pipe of a refrigerant circuit (not shown) outside the housing 11.

[0032] The scroll compression mechanism 4 is composed of the fixed scroll 21 and movable scroll 22. The fixed scroll 21 integrally includes a disk-shaped end plate 23 and an involute-shaped or spiral wrap 24 formed of a curve similar to an involute and erected on the surface (one side) of the end plate 23, and is fixed to the rear casing 9 with the surface of the end plate 23 on which the wrap 24 is erected facing the center plate 6. A discharge hole 26 is formed in the center of the end plate 23 of the fixed scroll 21, and this discharge hole 26 communicates with a discharge chamber 27 in the rear casing 9. In the figure, reference numeral 28 denotes a discharge valve provided at the opening of the discharge hole 26 on the back surface (the other side) of the end plate 23.

[0033] The movable scroll 22 is a scroll that revolves around the fixed scroll 21, and is integrally provided with a disk-shaped end plate 31, a spiral wrap 32 that is involute-shaped or has a curve similar to an involute and is erected on the surface (one side) of the end plate 31, and a boss 33 that is formed and protrudes from the center of the back surface (the other side) of the end plate 31. The movable scroll 22 is disposed so that the wrap 32 faces the wrap 24 of the fixed scroll 21 with the protruding direction of the wrap 32 facing the fixed scroll 21, and the wraps 32 and 32 mesh with each other, forming a pressure chamber 34 between each wrap 24 and 32.

[0034] That is, the wrap 32 of the movable scroll 22 faces the wrap 24 of the fixed scroll 21, and the ends of the wrap 32 and 24 mesh with each other so that they contact the surface of the end plate 23 and the surface of the end plate 31, respectively. An eccentric portion 36 is fitted into the boss 33 of the movable scroll 22 and is provided eccentrically from the axis of the drive shaft 14 at the other end of the drive shaft 14. When the drive shaft 14 is rotated together with the rotor 35 of the electric motor 2, the movable scroll 22 is configured to revolve around the fixed scroll 21 without rotating on its own axis.

[0035] Since the movable scroll 22 revolves eccentrically relative to the fixed scroll 21, the eccentric direction and contact position of each wrap 24, 32 move while rotating, and the pressure chamber 34 that has drawn refrigerant from the aforementioned suction portion 37 on the outside moves inward and gradually shrinks. As a result, the refrigerant is compressed and is finally discharged from the central discharge hole 26 through the discharge valve 28 into the discharge chamber 27.

[0036] 1, reference numeral 38 denotes an annular thrust plate. This thrust plate 38 serves to separate a back pressure chamber 39 formed between the back surface of the end plate 31 of the movable scroll 22 and the center plate 6 from a suction section 37 outside the scroll compression mechanism 4, and is positioned outside the boss 33 and interposed between the center plate 6 and the movable scroll 22.

[0037] Also, reference numeral 48 denotes a centrifugal oil separator mounted in the discharge chamber 27 of the rear casing 9 (housing 11). This oil separator 48 separates lubricating oil mixed in the refrigerant discharged from the scroll compression mechanism 4 to the discharge chamber 27, and the refrigerant flows toward the discharge port 20 and is discharged into the discharge pipe.

[0038] An oil reservoir 44 is formed in the rear casing 9 below the oil separator 48, and the oil separated from the refrigerant by the oil separator 48 flows into this oil reservoir 44 from the lower end of the oil separator 48. In the drawing, reference numeral 43 denotes a back pressure passage formed from the rear casing 9 to the center plate 6, and has an orifice 50. The discharge pressure reduced and adjusted by the orifice 50 of the back pressure passage 43 is supplied to the back pressure chamber 39 together with the oil in the oil reservoir 44 separated by the oil separator 48.

[0039] The pressure (back pressure) in the back pressure chamber 39 generates a back pressure load that presses the movable scroll 22 against the fixed scroll 21. This back pressure load presses the movable scroll 22 against the fixed scroll 21 against the compression reaction force from the pressure chamber 34 of the scroll compression mechanism 4, maintaining contact between the wraps 24, 32 and the end plates 31, 23, and enabling the refrigerant to be compressed in the pressure chamber 34.

[0040] On the other hand, the inverter case 8 is composed of a case body 10 which defines an inverter accommodating section 13 therein, and a cover 15 of the present invention which closes an opening on one end surface of the case body 10. The inverter 3 is accommodated in the inverter accommodating section 13, and the cover 15 is attached to the case body 10 after the inverter 3 has been accommodated in the inverter accommodating section 13.

[0041] 1, reference numeral 40 denotes a hermetic pin, and three pins are provided corresponding to the UVW phases of the three-phase electric motor 2. Each hermetic pin 40 penetrates the stator housing 7 and the case body 10, with one end connected to the coil of the stator 25 of the electric motor 2 housed in the motor chamber 12 and the other end electrically connected to a circuit board 49 of the inverter 3 housed in the inverter housing portion 13 via a connection terminal 51 called a power basket.

[0042] Here, a capacitor 52 is mounted on the stator housing 7 side of the substrate 49 of the inverter 3, and in addition to the connection terminal 51, an isolation transformer 53 and electrical components 54 that constitute the inverter 3 are also mounted on the cover 15 side. These hermetic pins 40, connection terminals 51, capacitor 52 and isolation transformer 53 are also electrical components that constitute the inverter 3, and in particular, the hermetic pins 40 and connection terminals 51 are electrical components that operate at a higher voltage than other electrical components (such as capacitor 52), while capacitor 52 is a low-voltage electrical component.

[0043] Furthermore, the dimension of the isolation transformer 53 from the substrate 49 toward the cover 15 is greater than that of the other electrical components 54. Furthermore, in this embodiment, the hermetic pins 40 and the connection terminals 51 (high-voltage electrical components) are disposed on the outer edge of the inverter accommodating section 13 (see FIG. 7).

[0044] Next, the shape of the cover 15 of this embodiment will be described with reference to Figures 2 to 8. Figure 2 is a perspective view of the cover 15 as seen from the outside, Figure 3 is a perspective view of the cover 15 as seen from the inside, Figure 4 is a plan view of the cover 15, Figure 5 is a cross-sectional view taken along line A-A in Figure 4, Figure 6 is a cross-sectional view taken along line B-B in Figure 4, Figure 7 is a cross-sectional view taken along line C-C in Figure 4, and Figure 8 is a cross-sectional view taken along line D-D in Figure 4.

[0045] The cover 15 used in the present invention is formed by pressing (without cutting) a metal sheet made of surface-treated steel plate with a predetermined thin thickness. The cover 15 is composed of an upper wall portion 41 having a shape as shown in each drawing including Fig. 1, a vertical wall portion 42 formed continuously with the outer periphery of the upper wall portion 41, and a seal flange portion 46 that projects outward continuously with the outer periphery of the vertical wall portion 42.

[0046] Numeral 47 denotes a bolt hole formed in this seal flange portion 46. Then, the cover 15 is attached to the case body 10 by placing the seal flange portion 46 against the open end face of the case body 10 as shown in Fig. 1 and inserting bolts (not shown) through the bolt holes 47 and screwing them into the case body 10.

[0047] 4, the cover 15 as a whole is made up of a circular portion 56 on one side and a square portion 57 continuing from the circular portion 56, and the center O of the circular portion 56 coincides with the center of the circle of the cylindrical stator housing 7. Furthermore, the upper wall portion 41 of the cover 15 of this embodiment is divided into four regions by a longitudinal boundary line 58 passing through the center O and a lateral boundary line 59 at the portion where the circular portion 56 and the square portion 57 connect (FIG. 4).

[0048] 4, which are partitioned by boundary lines 58 and 59 corresponding to the hermetic pins 40 and the connection terminals 51 (high-voltage electrical components), are defined as a flat surface 61, and the lower right, upper left, and upper right regions of FIG. 4 are defined as curved surfaces 62, 63, and 64, respectively. In this case, the intersection P of boundary lines 58 and 59 is the center of curvature of each of the curved surfaces 62 to 64, and each of the curved surfaces 62 to 64 is configured to be continuous with the flat surface 61 and to be lower in the outer circumferential direction of the cover 15.

[0049] In this embodiment, the radius of curvature of each of the curved surfaces 62 to 64 is different in the longitudinal and lateral directions of the cover 15. That is, if the radius of curvature of the curved surfaces 63 and 64 in the longitudinal direction of the cover 15 is R1 ( FIG. 5 ) and the radius of curvature of each of the curved surfaces 62 to 64 in the lateral direction of the cover 15 is R2 ( FIG. 8 ), the radius of curvature R1 in the longitudinal direction is larger than the radius of curvature R2 in the lateral direction (R2<R1). Furthermore, the isolation transformer 53, whose dimension from the board 49 toward the cover 15 is greater than the other electrical components 54, is located near the connection between the flat surface 61 and the curved surface 62, where the distance from the board 49 of the cover 15 is greater, and the capacitor 52 is located corresponding to the portion of the curved surfaces 63 and 64.

[0050] Furthermore, a recess 66 that protrudes toward the stator housing 7 (housing 11) is formed at the connection between the curved surfaces 63 and 64 of the upper wall portion 41. In this embodiment, this recess 66 abuts against the capacitor 52 (actually, the terminal portion for soldering the capacitor 52 to the substrate 49) and the corresponding position on the substrate 49 via an insulating heat dissipation material 67 that has high thermal conductivity. Note that the recess 66 may be directly abutted against the terminal portion of the capacitor 52 and that portion of the substrate 49 in an insulated state without using the heat dissipation material 67.

[0051] In addition, the angle X1 at which the vertical wall 42 (hereinafter referred to as 42A) continuing from the flat surface 61 rises from the seal flange portion 46 is larger than the angle X2 at which the vertical wall 42 in other portions rises (Figures 6 to 8).

[0052] In this way, the cover 15 that closes the inverter accommodating section 13 is formed from sheet metal having an upper wall section 41, a vertical wall section 42 formed continuously from the outer periphery of the upper wall section 41, and a seal flange section 46 that protrudes outward continuously from the outer periphery of the vertical wall section 42 and is attached to the case main body 10 (housing 11), and the upper wall section 41 is composed of a flat surface 61 and curved surfaces 62 to 64 that are continuous with the flat surface 61 and become lower in the outer periphery direction.Therefore, by forming the flat surface 61 of the upper wall section 41 in a position corresponding to the hermetic pins 40 and connection terminals 51 (high-voltage electrical components) that have a higher voltage than the other electrical components of the inverter 3, as in the embodiment, it is possible to avoid the hermetic pins 40 and connection terminals 51, which are at a high voltage, and to ensure an insulation distance between the upper wall section 41 and the hermetic pins 40, etc. without any problems.

[0053] This is particularly effective when the hermetic pins 40 and connection terminals 51 are arranged on the outer edge of the inverter accommodating section 13, as in the embodiment. Furthermore, by making the angle X1 at which the vertical wall section 42A located on the flat surface 61 corresponding to the hermetic pins 40 and connection terminals 51 rises from the seal flange section 46 larger than the angle X2 at other positions (X2<X1), it is possible to ensure the insulation distance between the vertical wall section 42 and the hermetic pins 40 and connection terminals 51.

[0054] Furthermore, by arranging the vicinity of the connection between the flat surface 61 and the curved surface 62 of the upper wall portion 41 to correspond to the isolation transformer 53, which has a larger dimension in the direction of the cover 15 than other electrical components, as in the embodiment, it is possible to minimize the dimension by which the cover 15 protrudes from the housing 11 while avoiding interference between the cover 15 and the isolation transformer 53.

[0055] Here, increasing the radius of curvature of the curved surfaces 62 to 64 of the upper wall portion 41 decreases the natural frequency of the cover 15, and decreasing the radius of curvature increases the natural frequency. Furthermore, decreasing the rise angles X1 and X2 of the vertical wall portion 42 smooths the connection with the upper wall portion 41, thereby increasing the natural frequency of the cover 15, and increasing the rise angles X1 and X2 decreases the natural frequency.

[0056] Therefore, in this embodiment, the radius of curvature of the curved surfaces 62 and 63 of the upper wall portion 41 of the cover 15 and the angle at which the vertical wall portion 42 rises from the seal flange portion 46 are adjusted to increase the natural frequency (mainly the primary natural frequency) of the cover 15 and to design it so as to deviate from the frequency of the vibratory forces of the scroll compression mechanism 4 and the electric motor 2, which are the vibration sources of the electric compressor 1. In other words, the natural frequency of the cover 15 is shifted in a direction higher than the resonance point with the vibratory forces of the scroll compression mechanism 4 and the electric motor 2.

[0057] The frequency of the vibratory force of the scroll compression mechanism 4 and the electric motor 2 varies depending on the operating state and is unclear, but is generally low. Therefore, in the present invention, the natural frequency of the cover 15 is set to be higher than the frequency range of this vibratory force (the frequency range of the vibratory force generated in operating states from low to high speeds). This is because a higher frequency makes the sound quieter even if the sound volume is the same. For example, if the frequency range of the vibratory force of the scroll compression mechanism 4 and the electric motor 2 is 1100 Hz to 2000 Hz, the radii of curvature of the curved surfaces 62 and 63 and the rising angles X1 and X2 of the vertical wall portions 42A and 42B are adjusted so that the natural frequency of the cover 15 is 2100 Hz.

[0058] This makes it possible to suppress the problem of the cover 15 resonating due to vibrations of the scroll compression mechanism 4 and the electric motor 2, and makes it possible to significantly reduce vibrations and noise caused by resonance of the cover 15.

[0059] In this case, by setting the radius of curvature of the curved surfaces 62 to 64 of the upper wall portion 41 to different values ​​in the longitudinal and lateral directions of the cover 15 as in the embodiment, it is possible to expand the adjustment range of the natural frequency of the cover 15.

[0060] Furthermore, because the cover 15 is made of sheet metal, it can be manufactured by pressing steel plate compared to aluminum die casting. This reduces the number of processes and saves energy, significantly reducing carbon dioxide emissions, contributing to environmental issues and reducing production costs. Furthermore, the present invention makes it possible to form sheet metal with a substantially uniform thickness to increase the natural frequency, thereby reducing weight and, when used in a vehicle air conditioning system, improving the performance of the vehicle. Furthermore, by forming the upper wall portion 41 of the sheet metal cover 15 with a flat surface 61 and curved surfaces 62-64 and forming the vertical wall portion 42 and further sealing flange portion 46 on its outer periphery, the strength of the cover 15 itself is also improved.

[0061] In addition, in this embodiment, a recess 66 that protrudes toward the stator housing 7 is formed in the upper wall portion 41 of the cover 15, and this recess 66 abuts against the capacitor 52 directly or via a heat dissipation material 67, so that heat generated from the capacitor 52 can be transferred to the cover 15 directly or via the substrate 49 and the heat dissipation material 67. This makes it possible to cool the capacitor 52 inside the inverter accommodating portion 13 using the cover 15.

[0062] It should be noted that the high-voltage electrical components in the present invention are not limited to the hermetic pin 40 shown in the embodiment, etc. Furthermore, it goes without saying that the electrical components that increase in size in the direction of the cover 15 are not limited to the isolation transformer 53 shown in the embodiment.

[0063] In addition, in the embodiment, both the radius of curvature of the curved surfaces 62 to 64 of the upper wall portion 41 of the cover 15 and the rising angles X1 and X2 of the vertical wall portions 42A and 42B are adjusted, but the natural frequency of the cover 15 may be increased by adjusting only one of them.

[0064] Furthermore, in the embodiment, the natural frequency of the cover 15 is set to be higher than the frequency range of the vibratory force of the scroll compression mechanism 4 and the electric motor 2, but it is not limited to this and may be set to be lower. Even in this case, although temporary resonance occurs during start-up and shutdown, it is possible to suppress the occurrence of resonance overall.

[0065] Furthermore, although the embodiments have been described using a scroll-type electric compressor as an example, the present invention can also be applied to inverter-integrated electric compressors of other compression types. Furthermore, the shapes shown in the embodiments are not limited to those shown therein, and it goes without saying that various modifications can be made without departing from the spirit of the present invention.

[0066] REFERENCE SIGNS LIST 1 Inverter-integrated electric compressor 2 Electric motor (motor) 3 Inverter 4 Scroll compression mechanism (compression mechanism) 7 Stator housing 8 Inverter case 10 Case body 11 Housing 13 Inverter accommodating section 15 Cover 40 Hermetic pin (high-voltage electrical component) 41 Upper wall section 42, 42A Vertical wall section 46 Seal flange section 51 Connection terminal (high-voltage electrical component) 52 Capacitor 53 Isolation transformer (electrical component whose dimension increases in the cover direction) 61 Flat surface 62 to 64 Curved surfaces 66 Recessed section 67 Heat dissipation material

Claims

1. An inverter-integrated electric compressor comprising a metal housing in which a motor and a compression mechanism are built, an inverter for driving the motor, an inverter accommodating section configured in the housing and accommodating the inverter, and a metal cover closing the inverter accommodating section, wherein the cover is made of sheet metal having an upper wall section, a vertical wall section formed continuous with the outer periphery of the upper wall section, and a seal flange section that protrudes outwardly continuous with the outer periphery of the vertical wall section and is attached to the housing, and the upper wall section is composed of a flat surface and a curved surface that is continuous with the flat surface and descends toward the outer periphery.

2. An inverter-integrated electric compressor as described in claim 1, characterized in that the natural frequency of the cover is increased by adjusting the radius of curvature of the curved surface of the upper wall portion and / or the angle at which the vertical wall portion rises from the seal flange portion.

3. The inverter-integrated electric compressor according to claim 2, wherein the radius of curvature of the curved surface of the upper wall portion is different in the longitudinal direction and the lateral direction of the cover.

4. An inverter-integrated electric compressor as described in claim 1, characterized in that the inverter has a plurality of electrical components, and the flat surface of the upper wall portion is formed in a position corresponding to the high-voltage electrical components which have a higher voltage than the other electrical components.

5. The inverter-integrated electric compressor according to claim 4, characterized in that the high-voltage electrical components are arranged on the outer edge of the inverter accommodating section, and the angle at which the vertical wall portion rises from the seal flange portion at the position corresponding to the high-voltage electrical components is larger than the angle at other positions.

6. An inverter-integrated electric compressor as described in claim 1, characterized in that the vicinity of the connection between the flat surface and the curved surface of the upper wall portion corresponds to an electrical component whose dimension in the cover direction is larger than the other electrical components.

7. An inverter-integrated electric compressor as described in any one of claims 4 to 6, characterized in that the cover has a recess formed in the upper wall portion and protruding towards the housing, and the recess abuts against the electrical components directly or via a heat dissipation material.

8. A manufacturing method for an inverter-integrated electric compressor comprising a metal housing incorporating a motor and a compression mechanism, an inverter for driving the motor, an inverter accommodating section configured in the housing and accommodating the inverter, and a metal cover closing the inverter accommodating section, wherein the cover is made of sheet metal having an upper wall section, a vertical wall section formed continuous with the outer periphery of the upper wall section, and a seal flange section that protrudes outwardly continuous with the outer periphery of the vertical wall section and is attached to the housing, and the natural frequency of the cover is increased by adjusting the radius of curvature of the curved surface of the upper wall section and / or the angle at which the vertical wall section rises from the seal flange section.

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