Electric compressor

Abstract

[Problem] To suppress generation of resonance in an inverter case during operation of an electric compressor. [Solution] An electric compressor 1 includes: an inverter 6 that drives an electric motor 4; a motor housing 20 that houses the electric motor 4; an inverter case 7 that is fixed to the motor housing 20 and houses the inverter 6; an inverter cover 32 that closes an opening of the inverter case 7; and a plurality of bolts 33a, 33b that fixes the inverter cover 32 to the inverter case 7. Each of the inverter case 7 and the inverter cover 32 extends in the first direction F1 intersecting the axial direction of the electric compressor 1, and protrudes in the first direction F1 from an outer contour of the motor housing 20. Ribs 40 are formed on the inverter cover 32. The ribs 40 extend linearly so as to connect through-holes for inserting the bolts 33a, 33b, the through-holes adjacent to each other at intervals in the first direction F1.

Description

Electric compressor

[0001] The present invention relates to an electric compressor.

[0002] Many electric compressors used to compress refrigerant in vehicle air conditioners include an electric motor that drives a compression mechanism and an inverter. The electric motor is driven by controlling the power supply to the electric motor while converting direct current (DC) power from an on-board battery or the like into alternating current (AC) power using the inverter. In this regard, Patent Document 1 discloses a method in which a motor housing that houses the electric motor and an inverter case that houses the inverter are butted together in the axial direction of the electric compressor and fixed together.

[0003] Japanese Patent Application Laid-Open No. 2022-138248

[0004] In recent years, electric vehicles have become increasingly high-voltage. Accordingly, inverters have become larger in size to ensure sufficient insulation distance at high voltages, resulting in larger inverter cases. As a result, the inverter case significantly protrudes outward from the outer contour of the motor housing when viewed in the axial direction of the electric compressor. This protruding portion of the inverter case has low bending rigidity and a low natural frequency, which could cause resonance during operation of the electric compressor. Furthermore, this resonance could potentially damage the inverter.

[0005] SUMMARY OF THE INVENTION It is therefore an object of the present invention to suppress the occurrence of resonance in an inverter case during operation of an electric compressor.

[0006] According to one aspect of the present invention, there is provided an electric compressor. The electric compressor includes an electric motor, a compression mechanism driven by the electric motor, an inverter driving the electric motor, a motor housing accommodating the electric motor, an inverter case fixed to the motor housing and accommodating the inverter, an inverter cover closing an opening of the inverter case, and a plurality of bolts for fastening the inverter cover to the inverter case. The motor housing, the inverter case, and the inverter cover are arranged in this order in the axial direction of the electric compressor. The inverter case and the inverter cover each extend in a first direction intersecting the axial direction of the electric compressor and protrude in the first direction beyond the outer contour of the motor housing. The inverter cover is formed with a plurality of through holes for inserting the plurality of bolts. The inverter cover is formed with a rib extending linearly so as to connect adjacent through holes spaced apart from each other in the first direction.

[0007] According to another aspect of the present invention, there is provided an electric compressor. The electric compressor includes an electric motor, a compression mechanism driven by the electric motor, an inverter driving the electric motor, a motor housing accommodating the electric motor, an inverter case fixed to the motor housing and accommodating the inverter, and an inverter cover closing an opening of the inverter case. The motor housing, the inverter case, and the inverter cover are arranged in this order in the axial direction of the electric compressor. The inverter case and the inverter cover each extend in a first direction intersecting the axial direction of the electric compressor and protrude in the first direction beyond the outer contour of the motor housing. The inverter cover is formed with a rib extending linearly in the first direction. When viewed in the axial direction of the electric compressor, one end of the rib is located inside the outer contour of the motor housing, and the other end of the rib is located outside the outer contour of the motor housing.

[0008] According to the present invention, it is possible to suppress the occurrence of resonance in the inverter case during operation of the electric compressor.

[0009] 1. A front view of an electric compressor according to a first embodiment of the present invention. 1. A cross-sectional view taken along line A-A in FIG. 1. 1. A partial cross-sectional view taken along line B-B in FIG. 1. 2. A front view of a motor housing according to the first embodiment. 3. A front view of an inverter cover according to the first embodiment. 4. A rear view of an inverter cover according to the first embodiment. 5. A front view of an inverter cover according to a second embodiment of the present invention. 6. A front view of an electric compressor according to a third embodiment of the present invention. 7. A partial cross-sectional view taken along line C-C in FIG. 8. 9. A front view of an inverter cover according to the third embodiment. 10. A rear view of an inverter cover according to the third embodiment. 11. A rear view of an inverter cover according to the fourth embodiment.

[0010] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

[0011] FIG. 1 is a front view of an electric compressor 1 according to a first embodiment of the present invention. FIG. 2 is a cross-sectional view taken along line A-A in FIG. 1, and is a schematic longitudinal cross-sectional view of the electric compressor 1. FIG. 3 is a partial cross-sectional view taken along line B-B in FIG. 1. FIG. 4 is a front view of a motor housing 20. FIG. 5 is a front view of an inverter cover 32. FIG. 6 is a rear view of the inverter cover 32. In the following description, the front and rear, left and right, and top and bottom of the electric compressor 1 will be defined as shown in FIGS. 1 and 2 for convenience.

[0012] The electric compressor 1 may be configured to be mounted on a vehicle to form part of a refrigerant circuit of a vehicle air conditioner, for example, and to compress and discharge a refrigerant (a gaseous refrigerant in this embodiment).

[0013] The electric compressor 1 has a housing 2, a rotating shaft 3, an electric motor 4 that rotates the rotating shaft 3, a compression mechanism 5 that is driven by the rotating shaft 3 and compresses a refrigerant, an inverter 6 that drives the electric motor 4, and an inverter case 7. The rotating shaft 3, the electric motor 4, and the compression mechanism 5 are housed in the housing 2. Here, the electric motor 4 and the compression mechanism 5 are arranged in series within the housing 2 in the axial direction of the rotating shaft 3 (i.e., the axial direction of the electric compressor 1). The inverter 6 is housed in the inverter case 7.

[0014] In this embodiment, the electric compressor 1 is an electric scroll compressor, and the compression mechanism 5 is a scroll compression mechanism. The compression mechanism 5 includes a fixed scroll 8 and an orbiting scroll (moving scroll) 9 that orbits relative to the fixed scroll 8. The fixed scroll 8 and the orbiting scroll 9 are arranged opposite to each other in the axial direction of the electric compressor 1.

[0015] The orbiting scroll 9 is driven by the rotary shaft 3 via a crank mechanism 10 and is configured to orbit relative to the fixed scroll 8 , in other words, to revolve around the axis of the fixed scroll 8 .

[0016] The crank mechanism 10 connects the rotary shaft 3 and the orbiting scroll 9, and is configured to convert the rotational motion of the rotary shaft 3 into the orbiting motion of the orbiting scroll 9. The compression mechanism 5 is configured to take in and compress low-pressure refrigerant as the orbiting scroll 9 orbits relative to the fixed scroll 8.

[0017] The housing 2 is made of, for example, metal. The housing 2 includes a motor housing 20, also referred to as a front housing, and a rear housing 21. The motor housing 20 (main body portion 24 described later) houses the rotating shaft 3 and the electric motor 4. The rear housing 21 (front tubular portion 25 described later) houses the compression mechanism 5. The housing 2 is configured by abutting the rear end surface of the motor housing 20 (rear end surface 24b described later) against the front end surface of the rear housing 21 (front end surface 25a described later) and fastening them together using fasteners (not shown) or the like.

[0018] The motor housing 20 (its main body 24) is tubular and extends in the front-to-rear direction (horizontal direction), and in this embodiment, is cylindrical. The main body 24 has a closed front end surface 24a and an open rear end surface 24b.

[0019] The rear housing 21 is cylindrical with two sections, front and rear. The rear housing 21 has a cylindrical front tubular portion 25 with an outer diameter equal to that of the main body portion 24 of the motor housing 20, and a cylindrical rear tubular portion 26 with an outer diameter smaller than that of the front tubular portion 25. A front end surface 25a of the front tubular portion 25 is open. A rear end surface 26b of the rear tubular portion 26 is closed. The front tubular portion 25 and the rear tubular portion 26 may be separate members.

[0020] The electric motor 4 is configured as, for example, a three-phase synchronous motor (brushless DC motor), and includes a stator core unit 13 and a rotor 14 .

[0021] The stator core unit 13 is fixed to the inner peripheral surface of the main body 24 of the motor housing 20. Direct current from an on-board battery (not shown) or the like is converted into three-phase alternating current by an inverter 6 and supplied to the stator core unit 13.

[0022] The rotor 14 is disposed radially inside the stator core unit 13 with a predetermined gap therebetween. A permanent magnet (not shown) is incorporated into the rotor 14. The rotor 14 is formed in a cylindrical shape, and the rotating shaft 3 is inserted into the hollow portion of the rotor 14 and fixed to the rotating shaft 3. In other words, the rotor 14 is integrated with the rotating shaft 3.

[0023] When a magnetic field is generated in the stator core unit 13 by power supply from the inverter 6 , a rotational force acts on the permanent magnet of the rotor 14 , causing the rotor 14 to rotate, thereby rotating the rotary shaft 3 .

[0024] A suction port P1 is formed adjacent to the front end surface 24a in the upper part of the main body 24 of the motor housing 20. The suction port P1 is connected to the low-pressure side of the refrigerant circuit via a connecting pipe or the like (not shown).

[0025] As shown in FIG. 1, in this embodiment, the electric compressor 1 has a suction chamber H1 into which a low-pressure refrigerant flows, a compression chamber H2 that compresses the low-pressure refrigerant, and a discharge chamber H3 from which the refrigerant compressed in the compression chamber H2 is discharged.

[0026] The suction chamber H1 is defined by the main body 24 of the motor housing 20. Low-pressure refrigerant from the refrigerant circuit flows into the suction chamber H1 through the suction port P1. The low-pressure refrigerant in the suction chamber H1 passes through a refrigerant passage L1 and reaches a space H4 near the compression mechanism 5.

[0027] The compression chamber H2 is formed within the compression mechanism 5, i.e., between the fixed scroll 8 and the orbiting scroll 9. The compression mechanism 5 is configured to compress the low-pressure refrigerant by taking in the low-pressure refrigerant from the space H4 when the compression chamber H2 is formed.

[0028] The discharge chamber H3 is disposed within the rear cylindrical portion 26 of the rear housing 21. A discharge hole L2 that connects the compression chamber H2 and the discharge chamber H3 is formed in the base plate 8a of the fixed scroll 8. Therefore, refrigerant compressed in the compression chamber H2 of the compression mechanism 5 is discharged through the discharge hole L2 into the discharge chamber H3. A check valve 15, such as a reed valve, is attached to the surface of the base plate 8a of the fixed scroll 8 facing the discharge chamber H3. The check valve 15 allows refrigerant to flow from the compression chamber H2 to the discharge chamber H3 but restricts refrigerant from the discharge chamber H3 to the compression chamber H2.

[0029] An oil separator 16 that separates lubricating oil contained in the refrigerant (gas refrigerant) is disposed within the discharge chamber H3. A discharge port P2 is formed in the upper portion of the rear cylindrical portion 26 of the rear housing 21 so as to communicate with the discharge chamber H3 (oil separator 16). The discharge port P2 is connected to the refrigerant circuit (high-pressure side) via a connecting pipe (not shown). Therefore, the lubricating oil is separated from the refrigerant that flows into the discharge chamber H3 by the oil separator 16, and the refrigerant is then discharged from the discharge port P2 to the high-pressure side of the refrigerant circuit.

[0030] Therefore, low-pressure refrigerant from the refrigerant circuit flows into the suction chamber H1 through the suction port P1, passes through the gap in the electric motor 4, and is then guided through the refrigerant passage L1 to the space H4 near the compression mechanism 5. The low-pressure refrigerant guided to the space H4 is taken into the compression chamber H2 of the compression mechanism 5 as the orbiting scroll 9 orbits and is compressed. The refrigerant compressed in the compression chamber H2 is discharged into the discharge chamber H3 through the discharge hole L2 (and the check valve 15), and then the lubricating oil is separated from the refrigerant in the oil separator 16. The refrigerant from which the lubricating oil has been separated in the oil separator 16 is then discharged from the discharge port P2 to the refrigerant circuit.

[0031] Here, the low-temperature, low-pressure refrigerant flowing into the suction chamber H1 through the suction port P1 can cool the front end surface 24a of the main body 24 of the motor housing 20 and the electric motor 4 (the stator core unit 13 and the rotor 14). The compression mechanism 5 driven by the electric motor 4 is configured to compress and discharge the refrigerant drawn into the main body 24 of the motor housing 20 (into the suction chamber H1) from the suction port P1.

[0032] In this embodiment, one or more protrusions 27 are provided on the upper portion of the housing 2 (at least one of the upper portion of the motor housing 20 and the upper portion of the rear housing 21). The protrusions 27 can be used to secure the housing 2 to the vehicle. The protrusions 27 protrude upward from the upper portion of the housing 2 (at least one of the upper portion of the motor housing 20 and the upper portion of the rear housing 21). The protrusions 27 can be, for example, rectangular parallelepiped (prism-shaped) or cylindrical.

[0033] The inverter case 7 is made of, for example, metal and is disposed in front of the main body 24 of the motor housing 20. The inverter case 7 is fixed in contact with the main body 24 of the motor housing 20.

[0034] The inverter case 7 has an end wall (bottom wall) 30 and a peripheral wall 31 that rises from the periphery of the end wall 30 and defines an opening facing the end wall 30. The inverter case 7 extends in a first direction F1 that intersects with the axial direction of the electric compressor 1. In this embodiment, the first direction F1 is a direction perpendicular to the axial direction of the electric compressor 1 and coincides with the up-down direction. In this embodiment, the inverter case 7 has a rectangular box shape that extends in the up-down direction, and the rear end of the inverter case 7 is defined by the end wall 30. An inverter cover 32 that closes the opening is removably attached to the front end of the inverter case 7. The inverter cover 32 is made of, for example, metal or resin.

[0035] The inverter cover 32 has a rectangular plate-shaped main body 32a and a peripheral wall 32b formed to protrude rearward from the peripheral edge of the main body 32a. The front end surface of the peripheral wall 31 of the inverter case 7 abuts against the rear end surface of the peripheral wall 32b of the inverter cover 32. In this embodiment, the rear housing 21, the motor housing 20, the inverter case 7, and the inverter cover 32 are arranged in this order in the axial direction of the electric compressor 1 (from rear to front).

[0036] In this embodiment, a plurality of bolts 33 a, 33 b are used to fix the inverter cover 32 to the inverter case 7. In this embodiment, three bolts 33 a and seven bolts 33 b are used. However, the number of bolts 33 a, 33 b is not limited to this and can be any number.

[0037] The bolt 33a is longer than the bolt 33b. The bolt 33a secures the inverter cover 32, the inverter case 7, and the main body 24 of the motor housing 20 together. For this purpose, the main body 32a and the peripheral wall 32b of the inverter cover 32 are formed with a plurality of (three in this embodiment) through holes 32c for inserting the male threads of the bolts 33a. The end wall 30 and the peripheral wall 31 of the inverter case 7 are formed with a plurality of (three in this embodiment) through holes 38a for inserting the male threads of the bolts 33a. Furthermore, the main body 24 (front end surface 24a) of the motor housing 20 is formed with a plurality of (three in this embodiment) female threads 24c for threading onto the male threads of the bolts 33a.

[0038] The bolts 33b secure the inverter cover 32 to the inverter case 7. To this end, a plurality of (seven in this embodiment) through holes 32d for inserting the male threads of the bolts 33b are formed in the main body 32a and the peripheral wall 32b of the inverter cover 32. In addition, a plurality of (seven in this embodiment) female threads 38b are formed in the peripheral wall 31 of the inverter case 7, into which the male threads of the bolts 33b are screwed.

[0039] The outer surface 30a of the end wall 30 of the inverter case 7 is made up of a contact portion 30a1 that contacts the front end surface 24a of the main body 24 of the motor housing 20, and an exposed portion 30a2 that is exposed to the outside.

[0040] The inverter 6 housed in the inverter case 7 has a plurality of (six in this embodiment) switching elements (power switching elements) 35 and a control board 36 on which a control circuit for controlling the switching elements 35 is mounted. The control board 36 is disposed within the inverter case 7 at a position away from the end wall 30 toward the opening. The control board 36 is attached to the inverter case 7 by an attachment member (not shown). The switching elements 35 are provided on a portion of the inner surface 30b of the end wall 30 of the inverter case 7 adjacent to the abutment portion 30a1 (in other words, adjacent to the front end surface 24a of the main body 24).

[0041] In addition to the bolt 33a, multiple (five in this embodiment) bolts 34 are used to secure the inverter case 7 to the main body 24 of the motor housing 20. Therefore, multiple (five in this embodiment) through-holes 38c are formed in the end wall 30 of the inverter case 7 for inserting the male threads of the bolts 34. Furthermore, multiple (five in this embodiment) female threads 24d are formed in the main body 24 (front end surface 24a) of the motor housing 20, into which the male threads of the bolts 34 are threaded. Therefore, the bolts 34 are screwed in from the inside of the inverter case 7. The bolts 33a, 33b and the bolt 34 are both screwed in from the front to the rear (i.e., in the same direction). In this embodiment, the multiple bolts 33a, 34 are arranged at intervals from each other along the circumferential direction of the main body 24 of the motor housing 20. In this embodiment, the plurality of bolts 33 a, 33 b are arranged at intervals from one another in the circumferential direction along the peripheral wall 31 of the inverter case 7. In other words, the plurality of bolts 33 a, 33 b are arranged at intervals from one another in the circumferential direction along the peripheral wall 32 b of the inverter cover 32.

[0042] In this embodiment, one or more protrusions 39 are provided on the upper part of the inverter case 7. The protrusions 39 can be used to fix the inverter case 7 to the vehicle. The protrusions 39 protrude upward from the upper part of the inverter case 7. The protrusions 39 can be, for example, rectangular or cylindrical.

[0043] In this embodiment, when viewed in the axial direction of the electric compressor 1 (in other words, when viewed from the front as shown in FIG. 1 ), the inverter case 7 and the inverter cover 32 extend significantly downward from the contour of the main body 24 of the motor housing 20 (i.e., the outer contour of the motor housing 20), forming a so-called cantilevered state. The natural frequency f of the bending deformation of this extending portion is expressed by the following equation (1):

[0044]

[0045] In this formula (1), f: natural frequency [Hz], k: equivalent stiffness [N / m], and m: equivalent mass [kg].

[0046] Here, the equivalent stiffness k indicates the stiffness of a system including the inverter 6, the inverter case 7, and the inverter cover 32. The equivalent mass m indicates the mass of a system including the inverter 6, the inverter case 7, and the inverter cover 32.

[0047] In this embodiment, in order to increase the natural frequency f, a pair of left and right ribs 40, 40 are formed on the outer surface (front surface) 32a1 of the inverter cover 32. The pair of left and right ribs 40, 40 extend parallel to each other in the vertical direction and spaced apart from each other in the horizontal direction.

[0048] The rib 40 protrudes forward from the outer surface 32a1 of the inverter cover and extends linearly in the vertical direction so as to connect the adjacent through holes 32c, 32d spaced apart from each other in the vertical direction.

[0049] In this embodiment, when viewed in the axial direction of the electric compressor 1, the through hole 32c located at the upper end (one end) of the rib 40 is located radially inward from the contour of the main body 24 of the motor housing 20 (the outer contour of the motor housing 20). Here, a bolt 33a is inserted into the through hole 32c located at the upper end of the rib 40.

[0050] In this embodiment, when viewed in the axial direction of the electric compressor 1, the through-hole 32d located at the lower end (the other end) of the rib 40 is located radially outward from the contour of the main body 24 of the motor housing 20 (the outer contour of the motor housing 20). Here, the bolt 33b is inserted into the through-hole 32d located at the lower end of the rib 40.

[0051] The rib 40 has recesses 41 formed at its upper and lower ends, each capable of accommodating the heads of the bolts 33a and 33b.

[0052] In this embodiment, the upper end (one end) of the rib 40 is located radially inward from the contour of the main body 24 of the motor housing 20 (the outer contour of the motor housing 20) when viewed in the axial direction of the electric compressor 1. Also, in this embodiment, the lower end (the other end) of the rib 40 is located radially outward from the contour of the main body 24 of the motor housing 20 (the outer contour of the motor housing 20) when viewed in the axial direction of the electric compressor 1.

[0053] The inverter cover 32 and the rib 40 are preferably formed as a single unit.

[0054] By forming a pair of left and right ribs 40, 40 on the outer surface 32a1 of the inverter cover 32 in this manner, the following effects (A) and (B) can be obtained with respect to the above-mentioned formula (1). (A) The root portion of the bending deformation can be reinforced with the rib 40, so the equivalent stiffness k can be increased. This contributes to increasing the above-mentioned natural frequency f. (B) The tip portion of the bending deformation (the lower end portion of the inverter case 7 and inverter cover 32) is not reinforced with the rib 40, so an increase in mass at this tip portion can be suppressed accordingly. This contributes to suppressing an increase in the above-mentioned equivalent mass m, and ultimately to suppressing a decrease in the above-mentioned natural frequency f.

[0055] According to this embodiment, the electric compressor 1 includes an electric motor 4, a compression mechanism 5 driven by the electric motor 4, an inverter 6 that drives the electric motor 4, a motor housing 20 that houses the electric motor 4, an inverter case 7 that is fixed to the motor housing 20 and houses the inverter 6, an inverter cover 32 that closes an opening of the inverter case 7, and a plurality of bolts 33a, 33b for fixing the inverter cover 32 to the inverter case 7. The motor housing 20, the inverter case 7, and the inverter cover 32 are arranged in this order in the axial direction of the electric compressor 1. The inverter case 7 and the inverter cover 32 each extend in a first direction F1 that intersects the axial direction of the electric compressor 1 and protrude in the first direction F1 beyond the outer contour of the motor housing 20. The inverter cover 32 has a plurality of through holes 32c, 32d formed therein for inserting the plurality of bolts 33a, 33b. The inverter cover 32 is formed with a rib 40 extending linearly in the first direction F1 to connect the adjacent through holes 32c, 32d spaced apart from each other, thereby suppressing the occurrence of resonance in the inverter case 7 during operation of the electric compressor 1.

[0056] Furthermore, according to this embodiment, a bolt 33a that secures the inverter cover 32, the inverter case 7, and the motor housing 20 together is inserted into the through hole 32c located at one end (upper end) of the rib 40, and a bolt 33b that secures the inverter cover 32 to the inverter case 7 is inserted into the through hole 32d located at the other end (lower end) of the rib 40. This allows the rib 40 to be connected to the motor housing 20, which does not vibrate easily, via the bolt 33a, thereby suppressing vibration of the rib 40 itself.

[0057] Furthermore, according to this embodiment, when viewed in the axial direction of the electric compressor 1, the through-hole 32c located at one end (upper end) of the rib 40 is located inside the outer contour of the motor housing 20, and the through-hole 32d located at the other end (lower end) of the rib 40 is located outside the outer contour of the motor housing 20. This allows the rib 40 to reinforce the root of the bending deformation described above, and ultimately makes it possible to increase the natural frequency f described above.

[0058] Furthermore, according to this embodiment, the inverter cover 32 is formed with a rib 40 that extends linearly in the first direction F1. When viewed in the axial direction of the electric compressor 1, one end (upper end) of the rib 40 is located inside the outer contour of the motor housing 20, and the other end (lower end) of the rib 40 is located outside the outer contour of the motor housing 20. This allows the rib 40 to reinforce the root of the bending deformation described above, and ultimately increases the natural frequency f described above.

[0059] Furthermore, according to this embodiment, the ribs 40 are formed on the outer surface 32a1 of the inverter cover 32. This allows the ribs 40 to be easily formed by integral molding with the inverter cover 32, for example.

[0060] According to this embodiment, the electric compressor 1 is mounted on a vehicle. The motor housing 20 extends horizontally. The first direction F1 is the up-down direction. The inverter case 7 has a protrusion 39 on the top for fixing to the vehicle. The inverter case 7 protrudes downward beyond the outer contour of the motor housing 20. Even in an electric compressor 1 having an inverter case 7 configured in this manner, it is possible to suppress the occurrence of resonance in the inverter case 7 during operation.

[0061] Next, a second embodiment of the present invention will be described with reference to Fig. 7. Fig. 7 is a front view of an inverter cover 32 in this embodiment. Differences from the first embodiment will be described.

[0062] In this embodiment, a pair of upper and lower ribs 44, 45 are formed on the outer surface (front surface) 32a1 of the inverter cover 32. The pair of upper and lower ribs 44, 45 extend in the left-right direction and are parallel to each other with a gap between them in the up-down direction.

[0063] The upper rib 44 protrudes forward from the outer surface 32a1 of the inverter cover and extends linearly in the left-right direction so as to connect adjacent through-holes 32c, 32c spaced apart from each other in the left-right direction. The left and right ends of the upper rib 44 overlap the upper ends of the pair of left and right ribs 40, 40, respectively.

[0064] In this embodiment, when viewed in the axial direction of the electric compressor 1, the through holes 32c, 32c located at both left and right ends of the upper rib 44 are located radially inward from the contour of the main body 24 of the motor housing 20 (the outer contour of the motor housing 20). Here, bolts 33a are inserted into the through holes 32c, 32c located at both left and right ends of the upper rib 44, respectively.

[0065] The lower rib 45 protrudes forward from the outer surface 32a1 of the inverter cover and extends linearly in the left-right direction. The lower rib 45 extends linearly so as to connect adjacent through-holes 32d, 32d spaced apart from each other in the left-right direction. The left and right ends of the lower rib 45 overlap the lower ends of the pair of left and right ribs 40, 40 described above.

[0066] In this embodiment, when viewed in the axial direction of the electric compressor 1, the through holes 32d, 32d located at both left and right ends of the lower rib 45 are located radially outward from the contour of the main body 24 of the motor housing 20 (the outer contour of the motor housing 20). Here, bolts 33b are inserted into the through holes 32d, 32d located at both left and right ends of the lower rib 45, respectively.

[0067] The pair of upper and lower ribs 44, 45 are also preferably formed integrally with the inverter cover 32 and the rib 40 by molding.

[0068] In particular, according to this embodiment, a pair of upper and lower ribs 44, 45 are formed on the outer surface 32a1 of the inverter cover 32. This makes it possible to suppress deformation and vibration of the inverter cover 32 itself.

[0069] In this embodiment, a pair of upper and lower ribs 44, 45 are formed, but one of these may be omitted.

[0070] Next, a third embodiment of the present invention will be described with reference to Figures 8 to 11. Figure 8 is a front view of the electric compressor 1 in this embodiment. Figure 9 is a partial cross-sectional view taken along the line CC in Figure 8. Figure 10 is a front view of the inverter cover 32. Figure 11 is a rear view of the inverter cover 32. Differences from the first embodiment will be described.

[0071] In the first embodiment described above, a pair of left and right ribs 40, 40 are formed on the outer surface (front surface) 32a1 of the inverter cover 32, but in this embodiment, a pair of left and right ribs 40', 40' are formed on the inner surface (rear surface) 32a2 of the inverter cover 32. The pair of left and right ribs 40', 40' are formed by widening a portion of the peripheral wall 32b of the inverter cover 32.

[0072] The relationship and role of the pair of left and right ribs 40', 40' and the through holes 32c, 32d in this embodiment is similar to that of the pair of left and right ribs 40, 40 described above, and therefore will not be described again.

[0073] In particular, according to this embodiment, the rib 40' is formed on the inner surface 32a2 of the inverter cover 32. This allows the rib 40' to be easily formed by integral molding with the inverter cover 32, for example.

[0074] Next, a fourth embodiment of the present invention will be described with reference to Fig. 12. Fig. 7 is a rear view of the inverter cover 32 in this embodiment. Differences from the third embodiment will be described.

[0075] In this embodiment, a pair of upper and lower ribs 44', 45' are formed on the inner surface (rear surface) 32a2 of the inverter cover 32. The pair of upper and lower ribs 44', 45' extend parallel to each other in the left-right direction and spaced apart from each other in the up-down direction.

[0076] The upper rib 44' protrudes rearward from the inner surface 32a2 of the inverter cover and extends linearly in the left-right direction. The upper rib 44' extends linearly so as to connect adjacent through-holes 32c, 32c spaced apart from each other in the left-right direction. Here, both left and right ends of the upper rib 44' overlap the upper ends of the pair of left and right ribs 40', 40' described above.

[0077] In this embodiment, when viewed in the axial direction of the electric compressor 1, the through holes 32c, 32c located at both left and right ends of the upper rib 44' are located radially inward from the contour of the main body 24 of the motor housing 20 (the outer contour of the motor housing 20). Here, bolts 33a are inserted into the through holes 32c, 32c located at both left and right ends of the upper rib 44', respectively.

[0078] The lower rib 45' protrudes rearward from the inner surface 32a2 of the inverter cover and extends linearly in the left-right direction. The lower rib 45' extends linearly so as to connect adjacent through-holes 32d, 32d spaced apart from each other in the left-right direction. Here, both left and right ends of the lower rib 45' overlap the lower ends of the pair of left and right ribs 40', 40' described above.

[0079] In this embodiment, when viewed in the axial direction of the electric compressor 1, the through holes 32d, 32d located at both left and right ends of the lower rib 45′ are located radially outward from the contour of the main body 24 of the motor housing 20 (the outer contour of the motor housing 20). Here, bolts 33b are inserted into the through holes 32d, 32d located at both left and right ends of the lower rib 45′, respectively.

[0080] The pair of upper and lower ribs 44', 45' are also preferably formed integrally with the inverter cover 32 and the rib 40'.

[0081] In particular, according to this embodiment, a pair of upper and lower ribs 44', 45' are formed on the inner surface 32a2 of the inverter cover 32. This makes it possible to suppress deformation and vibration of the inverter cover 32 itself.

[0082] In this embodiment, a pair of upper and lower ribs 44', 45' are formed, but either one of these may be omitted.

[0083] At least one of the pair of upper and lower ribs 44', 45' in the fourth embodiment may be formed on the inverter cover 32 in the first and second embodiments. Also, at least one of the pair of upper and lower ribs 44, 45 in the second embodiment may be formed on the inverter cover 32 in the third and fourth embodiments.

[0084] In the first to fourth embodiments described above, for the sake of convenience, the front-rear, left-right, and top-bottom directions of the electric compressor 1 are defined as described above. However, this is not intended to limit the orientation of the electric compressor 1. In other words, in the first to fourth embodiments described above, the electric compressor 1 is a horizontally-mounted electric compressor in which the electric motor 4 and the compression mechanism 5 are arranged in series in the horizontal direction within the housing 2, but it may also be a vertically-mounted electric compressor in which the electric motor 4 and the compression mechanism 5 are arranged in series in the vertical direction within the housing 2.

[0085] In the first to fourth embodiments described above, the electric compressor 1 is a scroll compressor, but the electric compressor 1 is not limited to a scroll compressor. For example, the electric compressor 1 may be a so-called swash plate compressor.

[0086] Examples of clauses that can be understood from the first to fourth embodiments are listed below.

[0087] [Clause 1] An electric compressor comprising: an electric motor; a compression mechanism driven by the electric motor; an inverter driving the electric motor; a motor housing accommodating the electric motor; an inverter case fixed to the motor housing and accommodating the inverter; an inverter cover closing an opening of the inverter case; and a plurality of bolts for fixing the inverter cover to the inverter case, wherein the motor housing, the inverter case, and the inverter cover are arranged in this order in an axial direction of the electric compressor, the inverter case and the inverter cover each extend in a first direction intersecting the axial direction of the electric compressor and protrude in the first direction beyond an outer contour of the motor housing, a plurality of through holes for inserting the plurality of bolts are formed in the inverter cover, and a rib is formed in the inverter cover extending linearly so as to connect adjacent through holes spaced apart from each other in the first direction.

[0088] [Clause 2] The electric compressor according to Clause 1, wherein a bolt for fixing the inverter cover, the inverter case, and the motor housing together is inserted into the through hole located at one end of the rib, and a bolt for fixing the inverter cover to the inverter case is inserted into the through hole located at the other end of the rib.

[0089] [Clause 3] The electric compressor according to Clause 1 or 2, wherein, when viewed in the axial direction of the electric compressor, the through hole located at one end of the rib is located inside an outer contour of the motor housing, and the through hole located at the other end of the rib is located outside the outer contour of the motor housing.

[0090] [Clause 4] An electric compressor comprising: an electric motor; a compression mechanism driven by the electric motor; an inverter driving the electric motor; a motor housing accommodating the electric motor; an inverter case fixed to the motor housing and accommodating the inverter; and an inverter cover closing an opening of the inverter case, wherein the motor housing, the inverter case, and the inverter cover are arranged in that order in an axial direction of the electric compressor, the inverter case and the inverter cover each extend in a first direction intersecting the axial direction of the electric compressor and protrude in the first direction beyond an outer contour of the motor housing, a rib is formed on the inverter cover and extends linearly in the first direction, and one end of the rib is located inside the outer contour of the motor housing as viewed in the axial direction of the electric compressor, and the other end of the rib is located outside the outer contour of the motor housing.

[0091] [Clause 5] The electric compressor according to any one of clauses 1 to 4, wherein the rib is formed on an outer surface of the inverter cover.

[0092] [Clause 6] The electric compressor according to any one of clauses 1 to 4, wherein the rib is formed on an inner surface of the inverter cover.

[0093] [Clause 7] The electric compressor according to any one of clauses 1 to 6, wherein the electric compressor is mounted on a vehicle, the motor housing extends in a horizontal direction, the first direction is a vertical direction, a protrusion for fixing the inverter case to the vehicle is provided on an upper portion of the inverter case, and the inverter case protrudes downward below an outer contour of the motor housing.

[0094] [Clause 8] The electric compressor according to any one of clauses 1 to 7, wherein the motor housing is cylindrical.

[0095] [Clause 9] The electric compressor according to any one of clauses 1 to 8, wherein the first direction is a direction perpendicular to an axial direction of the electric compressor.

[0096] [Clause 10] The electric compressor according to any one of Clauses 1 to 9, wherein the inverter case has an end wall, and the outer surface of the end wall includes a contact portion that contacts one end surface of the motor housing and an exposed portion that is exposed to the outside.

[0097] [Clause 11] The electric compressor according to Clause 10, wherein a suction port is formed in the motor housing adjacent to the end face, the compression mechanism is configured to compress and discharge refrigerant drawn into the motor housing from the suction port, and a switching element constituting the inverter is provided in a portion of the inner surface of the end wall adjacent to the abutting portion.

[0098] Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and it goes without saying that further modifications are possible based on the technical concept of the present invention.

[0099] DESCRIPTION OF SYMBOLS 1...electric compressor, 2...housing, 3...rotating shaft, 4...electric motor, 5...compression mechanism, 6...inverter, 7...inverter case, 8...fixed scroll, 8a...base plate, 9...orbiting scroll, 10...crank mechanism, 13...stator core unit, 14...rotor, 15...check valve, 16...oil separator, 20...motor housing, 21...rear housing, 24...main body portion, 24a...front end surface, 24b...rear end surface, 24c, 24d...female thread portion, 25...front cylindrical portion, 25a...front end surface, 26...rear cylindrical portion, 26b...rear end surface, 27...projection portion, 30...end wall, 30a...outer surface, 30a1...abutment part, 30a2...exposed part, 30b...inner surface, 31...circumferential wall, 32...inverter cover, 32a...main body, 32a1...outer surface, 32a2...inner surface, 32b...circumferential wall, 32c, 32d...through hole, 33a, 33b, 34...bolt, 35...switching element, 36...control board, 38a...through hole, 38b...female threaded portion, 38c...through hole, 39...projection portion, 40, 40'...rib, 41...recess, 44, 44', 45, 45'...rib, F1...first direction, H1...suction chamber, H2...compression chamber, H3...discharge chamber, H4...space, L1...refrigerant passage, L2...discharge hole, P1...suction port, P2...discharge port

Claims

1. An electric compressor comprising: an electric motor; a compression mechanism driven by the electric motor; an inverter driving the electric motor; a motor housing accommodating the electric motor; an inverter case fixed to the motor housing and accommodating the inverter; an inverter cover closing an opening of the inverter case; and a plurality of bolts for fixing the inverter cover to the inverter case, wherein the motor housing, the inverter case, and the inverter cover are arranged in that order in the axial direction of the electric compressor, the inverter case and the inverter cover each extend in a first direction intersecting the axial direction of the electric compressor and protrude in the first direction beyond an outer contour of the motor housing, a plurality of through holes for inserting the plurality of bolts are formed in the inverter cover, and a rib is formed on the inverter cover extending linearly so as to connect adjacent through holes at intervals in the first direction.

2. The electric compressor as described in claim 1, wherein a bolt for fixing the inverter cover, the inverter case and the motor housing together is inserted into the through hole located at one end of the rib, and a bolt for fixing the inverter cover to the inverter case is inserted into the through hole located at the other end of the rib.

3. The electric compressor according to claim 1, wherein, when viewed in the axial direction of the electric compressor, the through hole located at one end of the rib is located inside the outer contour of the motor housing, and the through hole located at the other end of the rib is located outside the outer contour of the motor housing.

4. An electric compressor comprising: an electric motor; a compression mechanism driven by the electric motor; an inverter driving the electric motor; a motor housing accommodating the electric motor; an inverter case fixed to the motor housing and accommodating the inverter; and an inverter cover closing an opening of the inverter case, wherein the motor housing, inverter case, and inverter cover are arranged in that order in the axial direction of the electric compressor, the inverter case and the inverter cover each extend in a first direction intersecting the axial direction of the electric compressor and protrude in the first direction beyond an outer contour of the motor housing, a rib is formed on the inverter cover extending linearly in the first direction, and when viewed in the axial direction of the electric compressor, one end of the rib is located inside the outer contour of the motor housing, and the other end of the rib is located outside the outer contour of the motor housing.

5. The electric compressor according to claim 1, wherein said ribs are formed on an outer surface of said inverter cover.

6. The electric compressor according to claim 1, wherein the rib is formed on the inner surface of the inverter cover.

7. The electric compressor according to claim 1, wherein the electric compressor is mounted on a vehicle, the motor housing extends in a horizontal direction, the first direction is an up-down direction, a protrusion for fixing the inverter case to the vehicle is provided on an upper portion of the inverter case, and the inverter case protrudes downwardly beyond an outer contour of the motor housing.

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