Inverter integrated electric compressor and manufacturing method of the same

Abstract

To provide an inverter integrated electric compressor which can suppress vibration and noise caused by resonance and avoid an electric component handling high voltage without trouble while reducing the weight and manufacturing costs of a cover for closing an inverter housing part.SOLUTION: An inverter integrated electric compressor includes a cover 15 for closing an inverter housing part 13. The cover 15 is formed of a sheet plate having: an upper wall part 41; a vertical wall part 42 which is formed continuously from an outer periphery of the upper wall part; and a seal flange part 46 which is continuous with an outer periphery of the vertical wall part, protrudes to the outer side, and is attached to a housing 11. The upper wall part 41 comprises a flat surface 61 and a curved surface 63 which is continuous with the flat surface and lowers in an outer peripheral direction.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an inverter-integrated electric compressor provided with a cover for closing an inverter accommodation portion formed in a housing, and a method for manufacturing the same.

Background Art

[0002] Conventionally, in this type of inverter-integrated electric compressor, particularly an electric compressor constituting an air conditioner for a vehicle, an inverter is housed and fixed in an inverter accommodation portion (inverter case) formed in a metal housing, and this inverter accommodation portion is further closed with a cover. Here, since the cover does not need to be designed for pressure resistance, it is usually composed of a thin plate of aluminum die-cast. However, when the vibration of the compression mechanism and the motor in the housing is transmitted to the cover, the cover vibrates and generates noise.

[0003] In this case, when the frequency of the exciting force of the compression mechanism and the motor coincides with or approximates the natural vibration frequency (eigenvalue) of the cover, resonance occurs, and there is a problem that the vibration and noise increase. Therefore, an electric compressor has been proposed in which a groove is formed in the cover to shift the natural vibration frequency of the cover from resonance (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, forming a shape like that in Patent Document 1 by aluminum die casting makes it difficult to reduce the weight, and increasing the thickness will increase the height dimension, making it difficult to achieve a compact design. Furthermore, in the case of aluminum die casting, after casting (die casting) from an aluminum ingot, a number of processes are required, such as removing strain by heat treatment and performing cutting, resulting in a large amount of carbon dioxide emissions and making it difficult to achieve carbon neutrality. Moreover, in the configuration of Patent Document 1, there are problems such as being unable to shift the natural frequency in only the lower direction.

[0006] Therefore, although it is not the cover of the inverter housing, for example, it is conceivable to adopt a curved surface shape as in Patent Document 2 for the cover to increase the natural frequency and avoid resonance. However, if the entire upper wall of the cover is configured with a curved surface, the cover will be close to the electrical components that make up the inverter near the outer edge. In an electric compressor that is required to have a higher voltage recently, there is a problem that it cannot be adopted in order to ensure the insulation distance from the high-voltage electrical components.

[0007] The present invention has been made to solve such conventional technical problems, and while reducing the weight and production cost of the cover that closes the inverter housing, suppressing vibration and noise caused by resonance, and avoiding high-voltage electrical components without any problems. An object of the present invention is to provide an inverter-integrated electric compressor and a manufacturing method thereof.

Means for Solving the Problems

[0008] The inverter-integrated electric compressor of the present invention includes a metal housing with a built-in motor and a compression mechanism, an inverter for driving the motor, an inverter housing configured in the housing for accommodating the inverter, and a metal cover for closing the inverter housing. The cover is made of sheet metal having an upper wall portion, a vertical wall portion continuously formed on the outer periphery of the upper wall portion, and a seal flange portion that continuously projects outward from the outer periphery of the vertical wall portion and is attached to the housing. The upper wall portion is composed of a flat surface and a curved surface that continuously becomes lower in the outer peripheral direction from the flat surface.

[0009] The inverter-integrated electric compressor according to 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 according to 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 at a position corresponding to a high-voltage electrical component whose voltage is higher than that of other electrical components.

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

[0013] The inverter-integrated electric compressor according to the invention of claim 6 is characterized in that, in the invention of claim 1, the vicinity of the connection portion 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 higher than that of other electrical components.

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

[0015] The manufacturing method of the inverter-integrated electric compressor according to the invention of claim 8, in manufacturing an inverter-integrated electric compressor including a metal housing with a built-in motor and a compression mechanism, an inverter for driving the motor, an inverter housing portion formed in the housing for accommodating the inverter, and a metal cover for closing the inverter housing portion, the cover is composed of a sheet metal having an upper wall portion, a vertical wall portion continuously formed on the outer periphery of the upper wall portion, and a seal flange portion continuously projecting outward from the outer periphery of the vertical wall portion and 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 portion and / or the angle at which the vertical wall portion rises from the seal flange portion.

Advantages of the Invention

[0016] According to the present invention, in an inverter-integrated electric compressor including a metal housing with a built-in motor and a compression mechanism, an inverter for driving the motor, an inverter housing portion formed in the housing for accommodating the inverter, and a metal cover for closing the inverter housing portion, the cover is formed from a sheet metal having an upper wall portion, a vertical wall portion continuously formed on the outer periphery of the upper wall portion, and a seal flange portion continuously projecting outward from the outer periphery of the vertical wall portion and attached to the housing, and the upper wall portion is composed of a flat surface and a curved surface that continuously becomes lower in the outer peripheral direction from this flat surface. Therefore, for example, by forming the flat surface of the upper wall portion at a position corresponding to a high-voltage electrical component where the voltage is higher compared to other electrical components of the inverter as in the invention of claim 4, it becomes possible to avoid the high-voltage electrical component and ensure the insulation distance between the upper wall portion and the high-voltage electrical component without any problems.

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

[0018] Further, by making the vicinity of the connection portion between the flat surface and the curved surface of the upper wall portion correspond to an electrical component whose dimension in the cover direction is larger than that of other electrical components as in the invention of claim 6, 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] And, as in the inventions of claim 2 and claim 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 is increased, so that the inconvenience of the cover resonating due to the vibration of the compression mechanism or the motor can be suppressed. As a result, it is possible to significantly reduce the vibration 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 values 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, since the cover is made of sheet metal, it can be manufactured by press working of a steel plate as compared with aluminum die casting. Since the number of processes is reduced and energy is saved, the carbon dioxide emissions can be significantly reduced, contributing to environmental problems, and the production cost can also be reduced. In addition, in the present invention, a sheet metal with a substantially constant plate thickness is formed to increase the natural frequency, so that weight reduction can be achieved. When used in an air conditioner for a vehicle, it is also possible to improve the performance of the vehicle. Also, by configuring the upper wall portion of the sheet metal cover with a flat surface and a curved surface and forming a vertical wall portion on its outer periphery, there is an effect of improving the strength of the cover itself.

[0022] Also, as in the invention of claim 7, by forming a recess protruding in the housing direction on the upper wall portion of the cover and bringing this recess into contact with the electrical component directly or via a heat dissipating material, the heat generated from the electrical component can be transmitted to the cover directly or via a heat dissipating material. As a result, it is possible to cool the electrical components in the inverter housing portion using the cover.

Brief Description of the Drawings

[0023]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Embodiments for Carrying Out the Invention

[0024] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic cross-sectional view of an inverter-integrated electric compressor 1 according to an embodiment to which the present invention is applied. The electric compressor (inverter-integrated electric compressor) 1 of the embodiment is used, for example, in a refrigerant circuit constituting an air conditioner for an electric vehicle, sucks a refrigerant as a working fluid of the air conditioner, compresses it, and discharges it to a discharge pipe. It is a so-called horizontally-mounted inverter-integrated scroll type electric compressor including a three-phase electric motor 2 as a motor in the present invention, an inverter 3 for driving the electric motor 2, and a scroll compression mechanism 4 as a compression mechanism driven by the electric motor 2.

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

[0026] These stator housings 7, inverter cases 8, and rear casings 9 are all made of metal (aluminum in the embodiment, excluding the cover 15 described later), and they are integrally joined to form the housing 11 of the electric compressor 1 of the embodiment.

[0027] A motor chamber 12 for accommodating the electric motor 2 is formed inside the stator housing 7. 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. After the electric motor 2 is accommodated in the motor chamber 12 through this opening, the center plate 6 is also accommodated through the same opening. Further, a sub-bearing 16 for rotatably supporting one end portion of the drive shaft 14 of the electric motor 2 is attached to the inner surface (motor chamber 12 side) of the end wall of the stator housing 7.

[0028] The center plate 6 has an opening on the side opposite to the electric motor 2 (the other end side). 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] Further, a through hole 17 through which the other end portion of the drive shaft 14 of the electric motor 2 is inserted is formed in the center plate 6. A main bearing 18 for rotatably supporting the other end portion of the drive shaft 14 on the scroll compression mechanism 4 side is attached inside the center plate 6 on the scroll compression mechanism 4 side of this through hole 17.

[0030] The electric motor 2 is composed of a stator 25 around which a coil is wound and fixed inside the peripheral wall of the stator housing 7, and a rotor 35 that rotates inside it. Then, for example, a direct current from a vehicle battery (not shown) is converted into a three-phase alternating current by the inverter 3 and supplied to the coil of the stator 25 of the electric motor 2, so that the rotor 35 is configured to be rotationally driven. And the drive shaft 14 is fixed to this rotor 35.

[0031] In addition, an intake port 30 is formed in the stator housing 7. The refrigerant inhaled from the intake port 30 passes through the motor chamber 12 of the stator housing 7 and then flows into the center plate 6, where it is inhaled into the intake portion 37 outside the scroll compression mechanism 4. As a result, the electric motor 2 is cooled by the inhaled refrigerant. Further, the refrigerant compressed by the scroll compression mechanism 4 is configured to be discharged from the discharge port 20 formed in the rear casing 9 from the discharge chamber 27 described later to the 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 the movable scroll 22 described above. The fixed scroll 21 integrally includes a disk-shaped mirror plate 23 and a spiral-shaped wrap 24 formed of an involute shape or a curve approximate thereto that stands on the surface (one surface) of the mirror plate 23. The surface of the mirror plate 23 on which the wrap 24 stands is fixed to the rear casing 9 with the center plate 6 side facing it. A discharge hole 26 is formed at the center of the mirror plate 23 of the fixed scroll 21, and this discharge hole 26 communicates with the discharge chamber 27 in the rear casing 9. In the figure, 28 is a discharge valve provided at the opening on the back (the other surface) side of the mirror plate 23 of the discharge hole 26.

[0033] The movable scroll 22 is a scroll that revolves and orbits with respect to the fixed scroll 21, and integrally includes a disk-shaped mirror plate 31, a spiral-shaped wrap 32 formed of an involute shape or a curve approximate thereto that stands on the surface (one surface) of the mirror plate 31, and a boss 33 protruding from the center of the back (the other surface) of the mirror plate 31. The movable scroll 22 is arranged such that the protruding direction of the wrap 32 faces the fixed scroll 21 side, the wrap 32 faces the wrap 24 of the fixed scroll 21, and they mesh with each other facing each other, forming a pressure chamber 34 between the wraps 24 and 32.

[0034] That is, the wrap 32 of the movable scroll 22 faces the wrap 24 of the fixed scroll 21, the tip of the wrap 32 contacts the surface of the mirror plate 23, the tip of the wrap 24 contacts the surface of the mirror plate 31, and they are engaged with each other. Further, an eccentric portion 36 provided eccentrically from the axis at the other end of the drive shaft 14 is fitted into the boss 33 of the movable scroll 22. 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 itself.

[0035] Since the movable scroll 22 revolves eccentrically around the fixed scroll 21, the eccentric direction and the contact position of each of the wraps 24 and 32 move while rotating. The pressure chamber 34 that has inhaled the refrigerant from the outer suction portion 37 described above gradually shrinks while moving inward. As a result, the refrigerant is compressed and finally discharged into the discharge chamber 27 through the discharge valve 28 from the central discharge hole 26.

[0036] In FIG. 1, reference numeral 38 denotes an annular thrust plate. This thrust plate 38 is for partitioning the back pressure chamber 39 formed between the back surface of the mirror plate 31 of the movable scroll 22 and the center plate 6 and the suction portion 37 outside the scroll compression mechanism 4, and is located outside the boss 33 and interposed between the center plate 6 and the movable scroll 22.

[0037] Reference numeral 48 denotes a centrifugal oil separator installed in the discharge chamber 27 of the rear casing 9 (housing 11). By this oil separator 48, the lubricating oil mixed in the refrigerant discharged from the scroll compression mechanism 4 into the discharge chamber 27 is separated, and the refrigerant goes toward the discharge port 20 and is discharged into the discharge pipe.

[0038] A storage oil chamber 44 is formed in a rear casing 9 below an oil separator 48, and oil separated from the refrigerant by the oil separator 48 flows into this storage oil chamber 44 from the lower end of the oil separator 48. In the figure, 43 is 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 configured to be supplied to the back pressure chamber 39 together with the oil in the storage oil chamber 44 separated by the oil separator 48.

[0039] Due to the pressure (back pressure) in this back pressure chamber 39, a back pressure load is generated that presses the movable scroll 22 against the fixed scroll 21. Due to this back pressure load, the movable scroll 22 is pressed against the fixed scroll 21 against the compression reaction force from the pressure chamber 34 of the scroll compression mechanism 4, and the contact between the laps 24, 32 and the end plates 31, 23 is maintained, 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 that constitutes an inverter housing portion 13 inside and a cover 15 of the present invention that closes the opening on one end face of the case body 10. The inverter 3 is housed in the inverter housing portion 13, and after the cover 15 houses the inverter 3 in the inverter housing portion 13, it is attached to the case body 10.

[0041] In FIG. 1, 40 are hermetic pins, and three are provided corresponding to each of the UVW phases of the three-phase electric motor 2. Each hermetic pin 40 is provided through the stator housing 7 and the case body 10. One end is connected to the coil of the stator 25 of the electric motor 2 housed in the motor chamber 12, and the other end is electrically connected to the substrate 49 of the inverter 3 housed in the inverter housing portion 13 via a connection terminal 51 called a power basket.

[0042] Here, on the substrate 49 of the inverter 3, a capacitor 52 is mounted on the side of the stator housing 7, and on the side of the cover 15, in addition to the connection terminal 51, an insulation transformer 53 and electrical components 54 constituting the inverter 3 are also mounted. These hermetic pins 40, connection terminals 51, capacitors 52, and insulation transformers 53 are also electrical components constituting the inverter 3. In particular, the hermetic pins 40 and connection terminals 51 are electrical components that have a higher voltage compared to other electrical components (such as the capacitor 52), and the capacitor 2 is an electrical component with a low voltage.

[0043] Also, the insulation transformer 53 has a dimension in the direction from the substrate 49 to the cover 15 that is higher than that of other electrical components 54. Furthermore, the hermetic pins 40 and connection terminals 51 (high-voltage electrical components) are arranged at the outer edge of the inverter housing portion 13 in the case of this embodiment (see FIG. 7).

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

[0045] The cover 15 used in the present invention is formed by press-working (cutting-less) a sheet metal having a predetermined thin thickness dimension made of a surface-treated steel plate. The cover 15 includes an upper wall portion 41 having a shape as shown in each figure including FIG. 1, a vertical wall portion 42 continuously formed on the outer periphery of the upper wall portion 41, and a seal flange portion 46 continuously projecting outward from the outer periphery of the vertical wall portion 42.

[0046] Note that 47 is a bolt hole formed in the seal flange portion 46. Then, by applying the seal flange portion 46 to the opening end surface of the case body 10 as shown in FIG. 1, inserting a bolt (not shown) through the bolt hole 47, and screwing it into the case body 10, the cover 15 is attached to the case body 10.

[0047] As shown in the plan view of FIG. 4 as a whole, the cover 15 is composed of a circular portion 56 on one side and a rectangular portion 57 continuous therewith, and the center O of the circular portion 56 coincides with the center of the circle of the cylindrical stator housing 7. Further, the upper wall portion 41 of the cover 15 in the embodiment is divided into four regions by a longitudinal boundary line 58 passing through the center O and a transverse boundary line 59 at the connecting portion between the circular portion 56 and the rectangular portion 57 (FIG. 4).

[0048] Then, the lower left region of FIG. 4 partitioned by the boundary line 58 and the boundary line 59 corresponding to the hermetic pin 40 and the connection terminal 51 (high-voltage electrical component) is a flat surface 61, and the lower right, upper left, and upper right regions of FIG. 4 are curved surfaces 62, 63, and 64, respectively. In this case, the intersection point P of the boundary line 58 and the boundary line 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 from the flat surface 61 and become lower in the outer peripheral direction of the cover 15.

[0049] Also, in the case of the embodiment, the radii of curvature of the curved surfaces 62 to 64 are different values in the longitudinal direction and the transverse direction of the cover 15. That is, when the radii of curvature of the curved surfaces 63 and 64 in the longitudinal direction of the cover 15 are R1 (FIG. 5) and the radii of curvature of the curved surfaces 62 to 64 in the transverse direction of the cover 15 are R2 (FIG. 8), the radius of curvature R1 in the longitudinal direction is larger than the radius of curvature R2 in the transverse direction (R2 < R1). Further, the insulating transformer 53, whose dimension in the direction from the substrate 49 to the cover 15 is higher than that of the other electrical component 54, is located corresponding to the vicinity of the connecting portion between the flat surface 61 and the curved surface 62 where the distance from the substrate 49 of the cover 15 is large, and the capacitor 52 is located corresponding to the portions of the curved surfaces 63 and 64.

[0050] Furthermore, a concave portion 66 protruding in the direction of the stator housing 7 (housing 11) is formed at the connecting portion between the curved surface 63 and the curved surface 64 of the upper wall portion 41. And, in the embodiment, this concave portion 66 is in contact with the capacitor 52 (actually, the terminal portion for soldering the capacitor 52 to the substrate 49) and the substrate 49 at the corresponding position via a heat dissipation material 67 having high heat conductivity and being insulating. Incidentally, the concave portion 66 may be directly brought into contact with the terminal portion of the capacitor 52 and the substrate 49 of that portion in an insulating state without using such a heat dissipation material 67.

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

[0052] Thus, the cover 15 for closing the inverter accommodation portion 13 is formed of sheet metal having an upper wall portion 41, a vertical wall portion 42 continuously formed on the outer periphery of the upper wall portion 41, and a seal flange portion 46 that continuously projects outward from the outer periphery of the vertical wall portion 42 and is attached to the case body 10 (housing 11). Since the upper wall portion 41 is composed of a flat surface 61 and curved surfaces 62 to 64 that continuously become lower in the outer peripheral direction from this flat surface 61, the flat surface 61 of the upper wall portion 41 as in the embodiment is formed at a position corresponding to the hermetic pin 40 or the connection terminal 51 (high-voltage electrical component) where the voltage is higher compared to other electrical components of the inverter 3. By doing so, it is possible to avoid the hermetic pin 40 and the connection terminal 51 that become high voltage and ensure the insulation distance between the upper wall portion 41 and the hermetic pin 40 etc. without any trouble.

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

[0054] Also, by making the vicinity of the connection portion between the flat surface 61 and the curved surface 62 of the upper wall portion 41 as in the embodiment correspond to the insulation transformer 53 where the dimension in the direction of the cover 15 is higher compared to other electrical components, it becomes possible to minimize the dimension by which the cover 15 projects from the housing 11 while avoiding interference between the cover 15 and the insulation transformer 53.

[0055] Here, if the radii of curvature of the curved surfaces 62 to 64 of the upper wall portion 41 are increased, the natural frequency of the cover 15 will decrease, and if the radii of curvature are decreased, the natural frequency will increase. Further, if the rising angles X1 and X2 of the vertical wall portion 42 are decreased, the connection with the upper wall portion 41 will become smoother, so the natural frequency of the cover 15 will increase, and if the rising angles X1 and X2 are increased, the natural frequency will decrease.

[0056] Therefore, in the embodiment, the radii of curvature of the curved surfaces 62 to 63 of the upper wall portion 41 of the cover 15 and the angles at which the vertical wall portion 42 rises from the seal flange portion 46 are adjusted to increase the natural frequency (mainly the first-order natural frequency) of the cover 15, and it is designed to deviate from the frequencies of the exciting forces of the scroll compression mechanism 4 and the electric motor 2 that are the vibration sources of the electric compressor 1. That is, the natural frequency of the cover 15 is shifted in a direction higher than the resonance point with the exciting forces of the scroll compression mechanism 4 and the electric motor 2.

[0057] Incidentally, the frequencies of the exciting forces of the scroll compression mechanism 4 and the electric motor 2 change depending on the operating state and are ambiguous, but basically they are low frequencies. Therefore, in the present invention, the natural frequency of the cover 15 is set to be higher than the range of the frequencies of these exciting forces (the frequency range of the exciting forces generated in the operating states from low speed to high speed). This is because a higher frequency sounds smaller even at the same sound volume. For example, assuming that the frequency range of the exciting forces 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 to 63 and the rising angles X1 and X2 of the vertical wall portions 42A and 42 are adjusted so that the natural frequency of the cover 15 becomes 2100 Hz.

[0058] As a result, it becomes possible to suppress the inconvenience that the cover 15 resonates due to the vibrations of the scroll compression mechanism 4 or the electric motor 2, and it becomes possible to significantly reduce the vibrations and noise caused by the resonance of the cover 15.

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

[0060] Furthermore, since the cover 15 is made of sheet metal, it can be manufactured by press working of a steel plate as compared with aluminum die casting, and the number of processes is reduced, resulting in energy saving. Therefore, the carbon dioxide emissions can be significantly reduced, contributing to environmental issues, and the production cost can also be reduced. In addition, in the present invention, it is possible to increase the natural frequency by forming a sheet metal with a substantially constant plate thickness, so that weight reduction can be achieved. When used in the air conditioner of a vehicle, it is also possible to improve the performance of the vehicle. Further, by forming the upper wall portion 41 of the sheet metal cover 15 with a flat surface 61 and curved surfaces 62 to 64 and forming a vertical wall portion 42 and a seal flange portion 46 on the outer periphery thereof, the strength of the cover 15 itself is also improved.

[0061] In addition, in the embodiment, a concave portion 66 protruding in the direction of the stator housing 7 is formed in the upper wall portion 41 of the cover 15, and this concave portion 66 is brought into contact with the capacitor 52 directly or via a heat radiating material 67. Therefore, the heat generated from the capacitor 52 can be transmitted to the cover 15 directly or via the substrate 49 and the heat radiating material 67. As a result, it becomes possible to cool the capacitor 52 in the inverter housing portion 13 using the cover 15.

[0062] Note that the high-voltage electrical components in the present invention are not limited to the hermetic pins 40 shown in the embodiment. Needless to say, the electrical components whose dimensions in the direction of the cover 15 are increased are not limited to the insulation transformer 53 shown in the embodiment.

[0063] In addition, in the embodiment, both the radii 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 42 are adjusted. However, 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 exciting force of the scroll compression mechanism 4 and the electric motor 2. However, it is not limited thereto, and it may be set to be lower. Even in that case, although temporary resonance occurs at startup / stop, it is possible to suppress the occurrence of resonance as a whole.

[0065] Furthermore, in the embodiment, the scroll type electric compressor has been described as an example, but the present invention is also applicable to inverter integrated electric compressors of other compression types. Needless to say, the shapes shown in the embodiments are not limited thereto, and various modifications can be made without departing from the spirit of the present invention.

Explanation of Reference Numerals

[0066] 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 accommodation part 15 Cover 40 Hermetic pin (high voltage electrical component) 41 Upper wall part 42, 42A Vertical wall parts 46 Seal flange part 51 Connection terminal (high voltage electrical component) 52 Capacitor 53 Insulation transformer (electrical component with increasing dimension in the cover direction) 61 Flat surface 62 - 64 Curved surfaces 66 Concave part 67 Heat dissipation material

Claims

1. An inverter-integrated electric compressor comprising a metal housing incorporating a motor and a compression mechanism, an inverter for driving the motor, an inverter housing portion formed in the housing for accommodating the inverter, and a metal cover for closing the inverter housing portion, wherein: the cover is made of sheet metal having an upper wall portion, a vertical wall portion continuously formed on the outer periphery of the upper wall portion, and a seal flange portion continuously projecting outward from the outer periphery of the vertical wall portion and attached to the housing; the upper wall portion is composed of a flat surface and a curved surface continuously extending from the flat surface and becoming lower in the outer peripheral direction, and the inverter-integrated electric compressor is characterized by this.

2. The inverter-integrated electric compressor according to claim 1, wherein 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 short transverse direction of the cover.

4. The inverter has a plurality of electrical components, and the flat surface of the upper wall portion is formed at a position corresponding to the high-voltage electrical component having a higher voltage compared to the other electrical components. The inverter-integrated electric compressor according to claim 1 is characterized by this.

5. The high-voltage electrical component is disposed at the outer edge portion of the inverter housing portion, and at the position corresponding to the high-voltage electrical component, the angle at which the vertical wall portion rises from the seal flange portion is larger than the angle at other positions. The inverter-integrated electric compressor according to claim 4 is characterized by this.

6. Near the connection portion between the flat surface and the curved surface of the upper wall portion, it corresponds to the electrical component having a larger dimension in the cover direction compared to the other electrical components. The inverter-integrated electric compressor according to claim 1 is characterized by this.

7. The cover is provided with a recess formed in the upper wall portion and projecting in the direction of the housing, and the recess abuts directly or via a heat dissipation material against the electrical component. The inverter-integrated electric compressor according to any one of claims 4 to 6 is characterized by this.

8. A method for 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 housing portion formed in the housing and accommodating the inverter, and a metal cover for closing the inverter housing portion, wherein the cover is composed of a sheet metal having an upper wall portion, a vertical wall portion continuously formed on the outer periphery of the upper wall portion, and a seal flange portion continuously projecting outward from the outer periphery of the vertical wall portion and attached to the housing, 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.

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