Electric compressor

Abstract

This electric compressor has a cover (7) that is fixed to a housing (1) by fixtures (31a-31f). The housing (1) and the fixtures (31a-31f) are made of metal. The cover (7) is made of a laminated damping steel sheet (70). The laminated damping steel sheet (70) includes a first steel sheet (71), a second steel sheet (72), and a resin material (73). The fixtures (31a-31f) come into contact with the first steel sheet (71) by fixing the cover (7) to the housing (1). The second steel sheet (72) has a second surface (72b) facing the housing (1). The second surface (72b) has first portions (711-716) and second portions (721-726). A gap between the second portions (721-726) and the housing (1) is sealed by a gasket (33). At least one of the first portions (711-716) is in direct contact with the housing (1).

Description

Electric compressor

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

[0002] Patent Document 1 discloses a conventional electric compressor. This electric compressor includes a compression mechanism, an electric motor, an inverter, a housing, and a cover. The compression mechanism compresses a fluid. The electric motor drives the compression mechanism. The inverter controls the drive of the electric motor. The housing houses the compression mechanism and the electric motor. The cover is fixed to the housing with multiple fasteners, and a housing chamber for accommodating the inverter is formed between the cover and the housing.

[0003] The cover is made of an aluminum alloy. The cover has a first surface and a second surface. The first surface faces the outside of the cover. The second surface is located opposite the first surface and faces the inverter inside the housing chamber. The second surface is provided with a plurality of ribs that protrude toward the inverter. The cover also has a plurality of through holes. Each through hole penetrates from the first surface to the second surface in the axial direction of the fastener. A respective fastener is inserted into each through hole.

[0004] In this type of electric compressor, vibrations generated by the compression mechanism and the electric motor during operation are transmitted to the housing, causing the housing to vibrate. The vibrations of the housing are then transmitted to the cover, causing the cover to vibrate, resulting in increased noise during operation. In this regard, the electric compressor described in Patent Document 1 uses ribs to increase the rigidity of the cover, thereby suppressing vibration of the cover during operation.

[0005] JP 2013-177826 A

[0006] However, electric compressors are required to be quieter. To address this issue, it is conceivable to suppress vibration of the cover during operation by increasing the thickness of the cover and increasing the rigidity of the cover. However, this would increase the size of the cover, which would in turn lead to an increase in the size of the electric compressor.

[0007] Additionally, electric compressors require a highly airtight housing to protect the inverter from water, dust, etc. Furthermore, electric compressors also require electromagnetic countermeasures to minimize the effect of external noise on the inverter as well as minimize the effect of noise from the inverter on external devices.

[0008] The present invention has been made in consideration of the above-described conventional situation, and has an object to be achieved by providing an electric compressor that is compact, has an excellent airtightness of the accommodation chamber, and has excellent electromagnetic protection measures for the inverter.

[0009] The electric compressor of the present invention is an electric compressor comprising: a compression mechanism that compresses a fluid; an electric motor that drives the compression mechanism; an inverter that controls the drive of the electric motor; a housing that accommodates the compression mechanism and the electric motor; and a cover that is fixed to the housing by a plurality of fasteners and forms an accommodation chamber between the housing and the cover to accommodate the inverter, wherein the housing and the fasteners are made of metal, the cover is made of a vibration-damping steel plate having a first steel plate, a second steel plate that is arranged spaced apart from the first steel plate in the axial direction of the fasteners, and a resin material provided between the first steel plate and the second steel plate, the cover is formed with a plurality of insertion holes that penetrate from the first steel plate to the second steel plate in the axial direction and through which each of the fasteners is inserted, and the housing is formed with a plurality of fixing holes that face each of the insertion holes and through which each of the fasteners is inserted and fixed, and each of the fixing holes abuts against the first steel plate by fixing the cover to the housing, The second steel plate has a first surface facing the resin material and a second surface located on the opposite side of the first surface in the axial direction and facing the housing when the cover is fixed to the housing; the second surface has a plurality of first portions on the inside of which each of the insertion holes opens, and second portions located outside each of the first portions; the space between the second portion and the housing is sealed by a gasket; and at least one of the first portions is in direct contact with the housing.

[0010] In the electric compressor of the present invention, the cover is made of a vibration-damping steel plate. The vibration-damping steel plate includes a first steel plate, a second steel plate, and a resin material, and the resin material suppresses the transmission of vibration between the first steel plate and the second steel plate. Therefore, in this electric compressor, it is not necessary to make the cover excessively thick in order to suppress vibration of the cover during operation.

[0011] In this electric compressor, the second steel plate has a first surface and a second surface, and the second surface faces the housing when the cover is fixed to the housing with the fasteners. The second surface has a plurality of first portions on the inside of which the insertion holes open, and second portions located outside the first portions. The gap between the second portions and the housing is sealed with a gasket. This effectively prevents water, dust, and the like from entering the chamber through the gap between the second portions and the housing.

[0012] Furthermore, in this electric compressor, the housing and each fastener are made of metal, and when fastening the cover to the housing, each fastener is inserted into and fastened to each fastening hole in the housing. Furthermore, when fastening the cover to the housing, each fastener abuts against the first steel plate. In this electric compressor, at least one of the first portions of the second steel plate directly abuts against the housing. In other words, at the location where the first portion directly abuts against the housing, the second steel plate and the housing make metallic contact without a gasket.

[0013] As a result, in this electric compressor, the cover and the housing can be suitably equipotentialized through the fixing device. Therefore, in this electric compressor, the influence of external noise on the inverter can be minimized, and the influence of noise from the inverter on external devices during operation can be minimized. Here, where the first part and the housing directly abut, the metal contact between them provides a suitable seal, even without a gasket. This also effectively prevents water, dust, and the like from entering the chamber through this area.

[0014] Therefore, the electric compressor of the present invention is miniaturized, has an excellent airtightness of the accommodation chamber, and is excellent in electromagnetic protection for the inverter.

[0015] In the electric compressor of the present invention, it is preferable that each of the first portions directly contacts the housing, which can more effectively equalize the potential between the cover and the housing and more effectively prevent water, dust, etc. from entering the chamber through the gap between the first portion and the housing.

[0016] It is preferable that the cover externally covers a portion of the housing when the cover is fixed to the housing, which makes it easier to form the cover and the housing than, for example, a configuration in which the housing externally covers a portion of the cover when the cover is fixed to the housing.

[0017] In this case, the second surface may have a third portion that is connected to the second portion and covers the outer peripheral surface of the housing from the outside. The gap between the third portion and the housing is preferably sealed with a gasket. This effectively prevents water, dust, etc. from entering the chamber through the gap between the third portion and the housing.

[0018] In the electric compressor of the present invention, the first steel plate may have a first metal plate body and a first plating layer covering the first metal plate body. The second steel plate may have a second metal plate body and a second plating layer covering the second metal plate body. The first plating layer and the second plating layer preferably have corrosion resistance. In this case, the first steel plate and the second steel plate, and thus the cover, are less susceptible to corrosion, thereby increasing the durability of the cover.

[0019] The electric compressor of the present invention is miniaturized, has an excellent airtightness of the housing chamber, and is excellent in electromagnetic protection for the inverter.

[0020] Fig. 1 is a partial cross-sectional view of an electric compressor according to an embodiment. Fig. 2 is a front view of the electric compressor according to an embodiment. Fig. 3 is an enlarged cross-sectional view of a main part of the electric compressor according to an embodiment, taken along line X1 in Fig. 1. Fig. 4 is an enlarged cross-sectional view of a main part of the electric compressor according to an embodiment, taken along line X2 in Fig. 1. Fig. 5 is a rear view of the electric compressor according to an embodiment, taken along line X2 in Fig. 1, showing a cover seen from the rear.

[0021] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An electric compressor according to an embodiment of the present invention is mounted on a vehicle (not shown) and forms a refrigeration circuit of an air conditioner for the vehicle.

[0022] 1 , the electric compressor of the embodiment includes a housing 1, an electric motor 3, a compression mechanism 5, a cover 7, and an inverter 9. The housing 1 has a first housing 11 and a second housing 13.

[0023] In this embodiment, the up-down direction and the front-rear direction of the electric compressor are defined by the arrows shown in Fig. 1. These up-down direction and front-rear direction are perpendicular to each other. In Fig. 2 and subsequent figures, the up-down direction and the front-rear direction are defined in accordance with Fig. 1. Note that these directions are merely examples for the sake of convenience, and the position of the electric compressor is changed as appropriate depending on the vehicle in which it is installed.

[0024] As shown in FIG. 1 , the first housing 11 is made of an aluminum alloy. The first housing 11 has a bottom wall 11a, a first side wall 11b, and a second side wall 11c. The bottom wall 11a is located at the front of the first housing 11 and extends radially from the electric compressor. The first side wall 11b is continuous with the bottom wall 11a and extends tubularly from the bottom wall 11a rearward in the axial direction of the electric compressor. The bottom wall 11a and the first side wall 11b form the first housing 11 into a cylindrical shape with a bottom that is open at the rear. A plurality of bolt holes 112 are formed in the first side wall 11b. Each bolt hole 112 opens at the rear end of the first side wall 11b and extends forward within the first side wall 11b. Note that FIG. 1 illustrates only one of the bolt holes 112.

[0025] A motor chamber 150 is defined within the first housing 11 by the bottom wall 11a and the first side wall 11b. Refrigerant gas is drawn into the motor chamber 150 from outside the housing 1 through an intake port (not shown) formed in the first side wall 11b. That is, in this electric compressor, the motor chamber 150 also functions as a suction chamber for the refrigerant gas. Refrigerant gas is an example of the "fluid" in the present invention. A support portion 15 is formed on the bottom wall 11a and protrudes into the motor chamber 150. A drive shaft 29 is rotatably supported on the support portion 15 via a bearing 17.

[0026] The second side wall 11c is continuous with the bottom wall 11a on the opposite side from the first side wall 11b, and extends cylindrically from the bottom wall 11a forward in the axial direction of the electric compressor. The second side wall 11c has a front end surface 110 located at its front end.

[0027] Six fixing holes 19 are formed in the second side wall 11c. The fixing holes 19 are arranged at predetermined intervals around the circumference of the second side wall 11c so as to correspond to insertion holes 75a to 75f (described later). Each fixing hole 19 opens to the front end surface 110 of the second side wall 11c and extends rearward inside the second side wall 11c. Although not shown in detail, a thread is formed on the inner circumferential surface of each fixing hole 19. The portions of the second side wall 11c where the fixing holes 19 are formed are thicker than the other portions of the second side wall 11c. Note that FIG. 1 and other figures illustrate only one of the six fixing holes 19. If there are multiple fixing holes 19, the number can be designed as needed.

[0028] The second housing 13 is also made of an aluminum alloy. The second housing 13 has a rear wall 13a and a third side wall 13b. The rear wall 13a is located at the rear end of the second housing 13 and extends in the radial direction of the electric compressor. A discharge port (not shown) is formed in the rear wall 13a.

[0029] The third side wall 13b is continuous with the rear wall 13a and extends forward from the rear wall 13a. The rear wall 13a and the third side wall 13b form the second housing 13 in a cylindrical shape with a bottom and an open front.

[0030] The second housing 13 is disposed rearward of the first housing 11, with the front end of the third side wall 13b abutting against the rear end of the first side wall 11b of the first housing 11. The first housing 11 and the second housing 13 are fastened to each other by inserting a plurality of bolts 111 into bolt holes 112 and fastening them to the bolt holes 112. This integrates the first housing 11 and the second housing 13. Although not shown in detail, a discharge chamber is formed within the second housing 13, and this discharge chamber communicates with the discharge port. The first and second housings 11 and 13 may also be formed of a metal other than an aluminum alloy. FIG. 1 also illustrates one of the plurality of bolts 111.

[0031] The electric motor 3 is housed in a motor chamber 150 of the first housing 11. The electric motor 3 has a stator 25, a rotor 27, a drive shaft 29, and a connecting portion (not shown). The stator 25 is fixed to the inner circumferential surface of the first side wall 11b within the motor chamber 150. The stator 25 has a coil (not shown). The rotor 27 is disposed inside the stator 25. The drive shaft 29 is fixed to the rotor 27 and rotates integrally with the rotor 27. The connecting portion is connected to the cluster block.

[0032] The compression mechanism 5 is housed behind the electric motor 3 within the first housing 11. A known scroll-type compression mechanism is employed as the compression mechanism 5. The compression mechanism 5 has a fixed scroll fixed to the inner circumferential surface of the first side wall 11b and a movable scroll disposed opposite the fixed scroll. The movable scroll is connected to a drive shaft 29 so as to be capable of transmitting power and is rotatable by the drive shaft 29. The fixed scroll and movable scroll mesh together to form a compression chamber therebetween. The compression chamber is in communication with a discharge chamber. The fixed scroll, movable scroll, and compression chamber are not shown in the drawings. Alternatively, a vane-type compression mechanism or the like may be employed as the compression mechanism 5.

[0033] 1 and 2 , the cover 7 is disposed in front of the housing 1, more specifically, in front of the second side wall 11c of the first housing 11. The cover 7 is formed by pressing a vibration-damping steel plate 70. In other words, the cover 7 is made of the vibration-damping steel plate 70.

[0034] 3 and 4 , the vibration-damping steel plate 70 is made up of a first steel plate 71, a second steel plate 72, and a resin plate 73. The resin plate 73 is an example of the "resin material" in the present invention. In the vibration-damping steel plate 70, the first steel plate 71 and the second steel plate 72 are arranged spaced apart in the front-rear direction. The resin plate 73 is arranged between the first steel plate 71 and the second steel plate 72.

[0035] The first steel plate 71 is composed of a first plate body 710a and a first plating layer 710b. The second steel plate 72 is composed of a second plate body 720a and a second plating layer 720b. The first plate body 710a and the second plate body 720a are made of steel. The first plate body 710a and the second plate body 720a are formed with the same plate thickness. The first plating layer 710b and the second plating layer 720b are formed of a zinc-nickel alloy. This provides the first plating layer 710b and the second plating layer 720b with corrosion resistance.

[0036] In the first steel plate 71, the first plate body 710a is entirely covered with the first plating layer 710b. Similarly, in the second steel plate 72, the second plate body 720a is entirely covered with the second plating layer 720b. This provides the first steel plate 71 and the second steel plate 72 with corrosion resistance. Note that the first plating layer 710b and the second plating layer 720b may be formed of other metals as long as they are corrosive-resistant.

[0037] The first steel plate 71 has a first surface 71a facing the outside and a second surface 71b located opposite the first surface 71a and facing the resin plate 73. The second steel plate 72 has a first surface 72a facing the resin plate 73 and a second surface 72b located opposite the first surface 72a and facing the outside. The first surface 71a forms the outer surface of the vibration-damping steel plate 70 and therefore the cover 7. The second surface 72b forms the inner surface of the cover 7. In other words, the first surface 71a faces the front of the cover 7, and the second surface 72b faces the first housing 11.

[0038] The resin plate 73 is formed by molding a viscoelastic resin into a plate shape. The resin plate 73 is formed to be thinner than the first steel plate 71 and the second steel plate 72. The resin plate 73 is adhered to the second surface 71 b of the first steel plate 71 and also to the first surface 72 a of the second steel plate 72. In this way, the resin plate 73 is positioned between the first steel plate 71 and the second steel plate 72 and fixed to them. As a result, the vibration-damping steel plate 70 is formed by integrating the first steel plate 71, the resin plate 73, and the second steel plate 72 with the resin plate 73 sandwiched between the first steel plate 71 and the second steel plate 72. 3 and 4, for ease of explanation, the thicknesses of the first steel plate 71, the second steel plate 72, and the resin plate 73, including the thicknesses of the first plating layer 710b and the second plating layer 720b, are exaggerated. Also, the first steel plate 71, the second steel plate 72, and the resin plate 73 are not shown in FIG.

[0039] 1, 2, and 5, the cover 7 has a main body portion 7a, an edge portion 7b, and a peripheral wall portion 7c. The main body portion 7a is located inside the edge portion 7b and protrudes forward beyond the edge portion 7b. In other words, the portion of the cover 7 that protrudes forward is the main body portion 7a.

[0040] The edge portion 7b is located outside the main body portion 7a and is connected to the main body portion 7a. The edge portion 7b extends outward from the main body portion 7a in the radial direction of the cover 7 and goes around the main body portion 7a in the circumferential direction. As a result, the edge portion 7b surrounds the main body portion 7a from the outside.

[0041] As shown in Figure 5, insertion holes 75a to 75f are formed in the edge portion 7b. The insertion holes 75a to 75f are arranged at predetermined intervals around the circumferential direction of the edge portion 7b. The insertion holes 75a to 75f penetrate the edge portion 7b in the front-rear direction. In other words, the insertion holes 75a to 75f extend from the first steel plate 71, through the resin plate 73, to the second steel plate 72.

[0042] The peripheral wall portion 7c is connected to the outermost portion of the edge portion 7b, i.e., the outer edge of the edge portion 7b. The peripheral wall portion 7c extends tubularly from the edge portion 7b toward the rear, following the outer edge of the edge portion 7b. As a result, the peripheral wall portion 7c has a standing wall shape that rises from the edge portion 7b. As shown in FIG. 1 , the peripheral wall portion 7c has a larger diameter than the second side wall 11c of the first housing 11.

[0043] As shown in FIG. 5, in the cover 7, the second surface 72b of the second steel plate 72 has first portions 711 to 716, second portions 721 to 726, third portions 731 to 736, and fourth portions 741 to 746.

[0044] The first portions 711-716 are each located in a portion of the second surface 72b that will become the edge portion 7b. As indicated by the dashed lines in FIG. 5 , the first portions 711-716 are each larger than the insertion holes 75a-75f. The first portion 711 has an insertion hole 75a opening on its inner side. Similarly, the first portion 712 has an insertion hole 75b opening on its inner side, and the first portion 713 has an insertion hole 75c opening on its inner side. The first portion 714 has an insertion hole 75d opening on its inner side, the first portion 715 has an insertion hole 75e opening on its inner side, and the first portion 716 has an insertion hole 75f opening on its inner side. Thus, the first portions 711-716 form annular shapes that surround the insertion holes 75a-75f from the outside, respectively.

[0045] The second portions 721 to 726 are portions of the second surface 72b that form the edge portion 7b, and are located outside the first portions 711 to 716. Specifically, the second portion 721 is located between the first portions 711 and 712 in the circumferential direction of the edge portion 7b, the second portion 722 is located between the first portions 712 and 713 in the circumferential direction of the edge portion 7b, and the second portion 723 is located between the first portions 713 and 714 in the circumferential direction of the edge portion 7b. In addition, the second portion 724 is located between the first portion 714 and the first portion 715 in the circumferential direction of the edge portion 7b, the second portion 725 is located between the first portion 715 and the first portion 716 in the circumferential direction of the edge portion 7b, and the second portion 726 is located between the first portion 716 and the first portion 711 in the circumferential direction of the edge portion 7b.

[0046] Thus, in the portion of the second surface 72b that becomes the edge portion 7b, the first portions 711 to 716 and the second portions 721 to 726 are alternately positioned in the circumferential direction of the edge portion 7b.

[0047] The third portions 731-736 are located on the second surface 72b in a portion that becomes the peripheral wall portion 7c and are connected to the second portions 721-726. Specifically, the third portion 731 is located on the peripheral wall portion 7c at a location that is on the outer periphery of the second portion 721 and is connected to the second portion 721. The third portion 732 is located on the peripheral wall portion 7c at a location that is on the outer periphery of the second portion 722 and is connected to the second portion 722. The third portion 732 is located on the peripheral wall portion 7c at a location that is on the outer periphery of the second portion 722 and is connected to the second portion 722. The third portion 733 is located on the peripheral wall portion 7c at a location that is on the outer periphery of the second portion 723 and is connected to the second portion 723. The third portion 734 is located on the peripheral wall portion 7c at a location that is on the outer periphery of the second portion 724 and is connected to the second portion 724. The third portion 735 is located on the peripheral wall 7c at a position on the outer circumferential side of the second portion 725, and is connected to the second portion 725. The third portion 736 is located on the peripheral wall 7c at a position on the outer circumferential side of the second portion 726, and is connected to the second portion 726.

[0048] The fourth portions 741 to 746 are located on the second surface 72b in a portion that becomes the circumferential wall portion 7c, and are located on the outer periphery of the first portions 711 to 716. Specifically, the fourth portion 741 is located on the circumferential wall portion 7c in a portion that becomes the outer periphery of the first portion 711, the fourth portion 742 is located on the circumferential wall portion 7c in a portion that becomes the outer periphery of the first portion 712, and the fourth portion 743 is located on the circumferential wall portion 7c in a portion that becomes the outer periphery of the first portion 713. The fourth portion 744 is located on the circumferential wall portion 7c in a portion that becomes the outer periphery of the first portion 714, the fourth portion 745 is located on the circumferential wall portion 7c in a portion that becomes the outer periphery of the first portion 715, and the fourth portion 746 is located on the circumferential wall portion 7c in a portion that becomes the outer periphery of the first portion 716.

[0049] Thus, in the portion of the second surface 72b that becomes the peripheral wall portion 7c, the third portions 731 to 736 and the fourth portions 741 to 746 are alternately positioned in the circumferential direction of the peripheral wall portion 7c.

[0050] 1, the cover 7 is disposed in front of the second side wall 11c of the first housing 11 with the second surface 72b facing the second side wall 11c. The edge 7b of the cover 7 is fastened to the second side wall 11c by fixing bolts 31a to 31f shown in FIG. 2. In this way, the cover 7 is fixed to the housing 1. Details regarding the fixing of the cover 7 to the housing 1 will be described later.

[0051] The fixing bolts 31a to 31f are an example of the "fixing device" of the present invention. The fixing bolts 31a to 31f all have the same configuration. The following description will be given using the fixing bolt 31a shown in FIG. 4 as an example. The fixing bolt 31a is made of metal, and extends axially in the front-to-rear direction. In other words, the axial direction of the fixing bolt 31a is parallel to the axial direction of the electric compressor.

[0052] The fixing bolt 31a has a head 310 and a threaded portion 311. The head 310 is located at the front end of the fixing bolt 31a. The head 310 is formed with a diameter larger than the insertion holes 75a to 75f. The threaded portion 311 is integral with the head 310 and extends rearward in the axial direction from the head 310. The threaded portion 311 is formed with a diameter smaller than the insertion holes 75a to 75f.

[0053] 1, the edge portion 7b of the cover 7 is fixed to the second side wall 11c, so that the peripheral wall portion 7c is positioned outside the second side wall 11c. The peripheral wall portion 7c covers a part of the second side wall 11c from the outside.

[0054] A storage chamber 8 is formed between the cover 7 and the bottom wall 11a of the first housing 11. The storage chamber 8 is surrounded by a second side wall 11c, and is closed at the front by the main body 7a of the cover 7.

[0055] 1 and 3, the gap between the cover 7 and the second side wall 11c, more specifically, the gap between the second portions 721 to 726 of the second surface 72b and the front end surface 110 of the second side wall 11c, and the gap between the third portions 731 to 736 of the second surface 72b and the outer peripheral surface of the second side wall 11c are sealed by gaskets 33. The gaskets 33 are formed by solidifying a liquid gasket 33a applied to the second surface 72b.

[0056] On the other hand, as shown in FIG. 4, no gasket 33 is present between the first portions 711 to 716 of the second surface 72b and the front end surface 110 of the second side wall 11c, and between the fourth portions 741 to 746 of the second surface 72b and the outer peripheral surface of the second side wall 11c.

[0057] The inverter 9 has a circuit board 9a and a plurality of semiconductors 9b provided on the circuit board 9a. The inverter 9 is accommodated in the accommodation chamber 8 with the circuit board 9a fixed to the bottom wall 11a. Lead wires (not shown) connected to the circuit board 9a of the inverter 9 are connected to the stator 25 through the cluster block and a connecting portion. This electrically connects the inverter 9 and the electric motor 3. The inverter 9 is also electrically connected to the vehicle battery (not shown).

[0058] In the electric compressor configured as described above, DC power is supplied from a battery to the inverter 9. The inverter 9 converts the DC power into AC power and supplies the AC power to the electric motor 3, thereby controlling the drive of the electric motor 3. The electric motor 3 supplied with AC power rotates the rotor 27 and the drive shaft 29, thereby driving the compression mechanism 5. The compression mechanism 5 compresses the refrigerant gas drawn through the suction port and discharges the compressed refrigerant gas from the discharge port.

[0059] In this electric compressor, the cover 7 is fixed to the housing 1 as follows. First, in a preparation step, the cover 7 is prepared. Next, in an application step, the liquid gasket 33a is applied to the portion of the second surface 72b of the second steel plate 72 that will become the edge portion 7b.

[0060] Next, the assembly process is performed. In this assembly process, the cover 7 is placed in front of the second side wall 11c of the first housing 11 with the second surface 72b facing the second side wall 11c. Then, the edge portion 7b, together with the liquid gasket 33a, is brought into contact with the front end surface 110 of the second side wall 11c. At this time, the insertion holes 75a to 75f of the cover 7 are aligned with the fixing holes 19 of the first housing 11 while facing each other in the front-rear direction. This completes the assembly process. Note that the circuit board 9a of the inverter 9 is fixed to the bottom wall 11a of the first housing 11 before the assembly process is completed.

[0061] Next, the fixing process is performed. In the fixing process, as shown in FIG. 2, the threaded portions 311 of the fixing bolts 31a to 31f are inserted into the insertion holes 75a from the front side of the cover 7, i.e., from the first steel plate 71 side. Then, each threaded portion 311 is screwed into the fixing hole 19. To explain this in more detail using the fixing bolt 31a as an example, as shown in FIG. 4, the threaded portion 311 of the fixing bolt 31a is inserted from the insertion hole 75a into the fixing hole 19 of the first housing 11. Then, the threaded portion 311 is screwed into the fixing hole 19. Furthermore, by screwing the threaded portion 311 into the fixing hole 19 in this manner, the head 310 of the fixing bolt 31a abuts against the first steel plate 71 around the insertion hole 75a.

[0062] In this way, the fixing process is completed by fixing the fixing bolts 31a to 31f in the respective fixing holes 19. As a result, as shown in Fig. 1, the edge portion 7b of the cover 7 is fastened and fixed to the second side wall 11c while being pressed against the front end surface 110 of the second side wall 11c from the front. Then, by fixing the edge portion 7b to the second side wall 11c in this way, the peripheral wall portion 7c of the cover 7 comes into a state in which it covers part of the outer peripheral surface of the second side wall 11c from the outside.

[0063] In this electric compressor, the assembly and fixing processes are completed before the liquid gasket 33a applied to the second surface 72b in the application process solidifies. As a result, taking the area around the insertion hole 75a on the second surface 72b as an example, as shown in FIG. 4 , the liquid gasket 33a applied around the insertion hole 75a on the second surface 72b is drawn into the fixing hole 19 along with the threaded portion 311 of the fixing bolt 31a as the threaded portion 311 threads into the fixing hole 19. As a result, in this electric compressor, the area around the insertion hole 75a on the second surface 72b, i.e., the first portion 711, is almost completely free of the liquid gasket 33a. Furthermore, the fourth portion 741 connected to the first portion 711 is also almost completely free of the liquid gasket 33a. The same applies to the first portions 712 to 716 and the fourth portions 742 to 746.

[0064] On the other hand, as shown in FIG. 3 , on the second surface 72b, the liquid gasket 33a is present between the second portions 721-726 and the front end surface 110 of the second side wall 11c. Here, as described above, during the fixing process, the edge portion 7b is fixed to the second side wall 11c while being pressed from the front against the front end surface 110 of the second side wall 11c. Therefore, a portion of the liquid gasket 33a present between the second portions 721-726 and the front end surface 110 of the second side wall 11c protrudes into the third portions 731-736 connected to the second portions 721-726. Therefore, the liquid gasket 33a is also present between the third portions 731-736 of the second surface 72b and the outer peripheral surface of the second side wall 11c. Furthermore, a portion of the liquid gasket 33a applied to the second surface 72b protrudes inside the second side wall 11c, i.e., into the accommodation chamber 8.

[0065] Then, the liquid gasket 33a solidifies to form the gasket 33, and in this electric compressor, the gap between the second portions 721 to 726 of the second surface 72b and the front end surface 110 of the second side wall 11c, and the gap between the third portions 731 to 736 of the second surface 72b and the outer peripheral surface of the second side wall 11c are sealed by the gasket 33. On the other hand, the gasket 33 is not present between the first portions 711 to 716 and the front end surface 110 of the second side wall 11c, and between the fourth portions 741 to 746 and the outer peripheral surface of the second side wall 11c.

[0066] 3 and 4, in this electric compressor, the cover 7 is made of a vibration-damping steel plate 70. In the vibration-damping steel plate 70, the resin plate 73 absorbs vibration energy between the first steel plate 71 and the second steel plate 72. Therefore, in this electric compressor, although the housing 1 inevitably vibrates during operation, the cover 7 suppresses the transmission of vibration between the first steel plate 71 and the second steel plate 72. Therefore, in this electric compressor, even if vibration is transmitted from the housing 1 to the cover 7 during operation, the cover 7 is less likely to vibrate. As a result, in this electric compressor, there is no need to make the plate thickness of the cover 7 excessively thick in order to suppress vibration of the cover 7 during operation.

[0067] Furthermore, in this electric compressor, the gap between the second portions 721 to 726 of the second surface 72b and the front end surface 110 of the second side wall 11c is sealed by a gasket 33. Furthermore, the gap between the third portions 731 to 736 of the second surface 72b and the outer peripheral surface of the second side wall 11c is also sealed by a gasket 33. As a result, in this electric compressor, water, dust, and the like can be suitably prevented from entering the accommodation chamber 8 from between the second portions 721 to 726 and the front end surface 110 of the second side wall 11c, and between the third portions 731 to 736 and the outer peripheral surface of the second side wall 11c.

[0068] In this electric compressor, the first housing 11 and the fixing bolts 31a to 31f are made of metal. When fixing the edge portion 7b of the cover 7 to the second side wall 11c, the fixing bolts 31a to 31f are fixed to the fixing holes 19 in the second side wall 11c by threading their threaded portions 311 into the fixing holes 19. In other words, by fixing the edge portion 7b to the second side wall 11c, the threaded portions 311 of the fixing bolts 31a to 31f come into contact with the second side wall 11c. Furthermore, the heads 310 of the fixing bolts 31a to 31f abut against the first steel plate 71 around the insertion holes 75a to 75f.

[0069] As described above, in this electric compressor, no gasket 33 is present between the first portions 711-716 and the front end surface of the second side wall 11c. Therefore, by fixing the edge portion 7b to the second side wall 11c, all of the first portions 711-716 are in direct contact with the front end surface 110 of the second side wall 11c. In other words, in the first portions 711-716, the second steel plate 72 and the second side wall 11c are in metal contact with each other without the gasket 33 interposed therebetween.

[0070] As a result, in this electric compressor, the cover 7 and the first housing 11 can be suitably equipotentialized through the fixing bolts 31a to 31f. Therefore, in this electric compressor, the influence of external noise on the inverter 9 can be minimized, and the influence of noise from the inverter 9 on external devices during operation can be minimized. The gap between the first portions 711 to 716 and the front end surface 110 of the second side wall 11c is suitably sealed by metal contact between the first portions 711 to 716 and the front end surface 110 of the second side wall 11c, even without the gasket 33. This effectively prevents water, dust, and the like from entering the accommodation chamber 8 through this area.

[0071] Therefore, the electric compressor of the embodiment is miniaturized, has excellent airtightness of the accommodation chamber 8, and is excellent in electromagnetic protection for the inverter 9.

[0072] In particular, in this electric compressor, when fixing the cover 7 to the housing 1, the assembly process and the fixing process are completed before the liquid gasket 33a applied to the second surface 72b in the application process solidifies. Therefore, by utilizing the engagement of the threaded portions 311 of the fixing bolts 31a to 31f with the fixing holes 19 and the fluidity of the liquid gasket 33a before solidification, it is possible to ensure that the liquid gasket 33a is almost completely absent from the first portions 711 to 716. As a result, in this electric compressor, it is not necessary to mask the first portions 711 to 716 during the application process to prevent the liquid gasket 33a from being applied to the first portions 711 to 716. Therefore, in this electric compressor, the application process can be easily performed.

[0073] Furthermore, by completing the assembly and fixing processes before the liquid gasket 33a solidifies, the liquid gasket 33a that protrudes from the second portions 721 to 726 allows the gasket 33 to effectively seal the gap between the third portions 731 to 736 and the outer peripheral surface of the second side wall 11c.

[0074] Furthermore, in this electric compressor, the edge portion 7b of the cover 7 is fixed to the second side wall 11c, so that the peripheral wall portion 7c of the cover 7 covers a portion of the outer circumferential surface of the second side wall 11c from the outside. This makes it easier to form the cover 7 and the second side wall 11c in this electric compressor than in a configuration in which, for example, the peripheral wall portion 7c enters the inside of the second side wall 11c while the cover 7 is fixed to the second side wall 11c, thereby covering the peripheral wall portion 7c from the outside by the second side wall 11c. Furthermore, because the peripheral wall portion 7c covers a portion of the outer circumferential surface of the second side wall 11c from the outside, in this electric compressor, it is easier to provide a gasket 33 between the peripheral wall portion 7c and the second side wall 11c.

[0075] In this electric compressor, the first steel plate 71 and the second steel plate 72 of the vibration-damping steel plate 70 have first and second plating layers 710b and 720b, respectively. This makes the first steel plate 71 and the second steel plate 72, and therefore the cover 7, corrosion-resistant, and therefore the durability of this electric compressor is also high. In addition, the first and second plating layers 710b and 720b make the first steel plate 71 and the second steel plate 72 smooth, respectively, and therefore the first steel plate 71 and the second steel plate 72 can be firmly fixed to the resin plate 73.

[0076] Although the present invention has been described above with reference to the examples, it goes without saying that the present invention is not limited to the above examples and can be modified and applied as appropriate within the scope of the invention.

[0077] For example, in the electric compressor of the embodiment, all of the first portions 711 to 716 are in direct contact with the front end surface 110 of the second side wall 11c. However, the present invention is not limited to this, and at least one of the first portions 711 to 716 may be in direct contact with the front end surface 110 of the second side wall 11c.

[0078] In the electric compressor of the embodiment, the gasket 33 between the peripheral wall portion 7c and the second side wall 11c may be omitted.

[0079] In the electric compressor of the embodiment, the fixing bolts 31a to 31f are the "fixing devices" of the present invention. However, the "fixing devices" of the present invention are not limited to these, and may be metal rivets or the like.

[0080] In the electric compressor of the embodiment, the first steel plate 71 has a first plate body 710a and a first plating layer 710b, and the second steel plate 72 has a second plate body 720a and a second plating layer 720b. However, without being limited to this, the first steel plate 71 and the second steel plate 72 may be formed only from the first plate body 710a and the second plate body 720a, respectively, which are made of an alloy of zinc and aluminum.

[0081] In the electric compressor of the embodiment, the first portions 711 to 716 may be masked during the coating process.

[0082] In the electric compressor of the embodiment, the refrigerant gas is the "fluid" in the present invention, but the present invention is not limited to this and air, oxygen, etc. may also be the "fluid" in the present invention.

[0083] The present specification also includes the following inventions: (Note 1) An electric compressor comprising: a compression mechanism that compresses fluid; an electric motor that drives the compression mechanism; an inverter that controls the drive of the electric motor; a housing that accommodates the compression mechanism and the electric motor; and a cover that is fixed to the housing by a plurality of fasteners and forms an accommodation chamber between the housing and the cover to accommodate the inverter, wherein the housing and the fasteners are made of metal, the cover is made of a vibration-damping steel plate having a first steel plate, a second steel plate that is arranged spaced apart from the first steel plate in the axial direction of the fasteners, and a resin material provided between the first steel plate and the second steel plate, the cover is formed with a plurality of insertion holes that penetrate from the first steel plate to the second steel plate in the axial direction and through which each of the fasteners is inserted, and the housing is formed with a plurality of fixing holes that face each of the insertion holes and through which each of the fasteners is inserted and fixed, and each of the fixing holes abuts against the first steel plate by fixing the cover to the housing, The electric compressor is characterized in that the second steel plate has a first surface facing the resin material and a second surface located on the opposite side of the first surface in the axial direction and facing the housing when the cover is fixed to the housing, the second surface having a plurality of first portions into which the insertion holes respectively open and second portions located outside the first portions, the gap between the second portions and the housing is sealed by a gasket, and at least one of the first portions is in direct contact with the housing. (Appendix 2) The electric compressor according to Appendix 1, in which all of the first portions are in direct contact with the housing. (Appendix 3) The electric compressor according to Appendix 1 or 2, in which the cover covers a part of the housing from the outside when fixed to the housing. (Appendix 4) The electric compressor according to Appendix 3, in which the second surface has a third portion connecting to the second portion and covering the outer peripheral surface of the housing from the outside, and the gap between the third portion and the housing is sealed by the gasket.(Appendix 5) The electric compressor according to any one of Appendices 1 to 4, wherein the first steel plate has a first plate body made of metal and a first plating layer covering the first plate body, the second steel plate has a second plate body made of metal and a second plating layer covering the second plate body, and the first plating layer and the second plating layer are corrosion-resistant.

[0084] The present invention can be used in vehicle air conditioning systems and the like.

[0085] REFERENCE SIGNS LIST 1 Housing 3 Electric motor 5 Compression mechanism 7 Cover 8 Storage chamber 9 Inverter 31a to 31f Fixing bolts (fixing devices) 33 Gasket 70 Vibration-damping steel plate 71 First steel plate 72 Second steel plate 72a First surface 72b Second surface 73 Resin plate (resin material) 75a to 75f Insertion holes 710a First plate body 710b First plating layer 711 to 716 First portion 720a Second plate body 720b Second plating layer 721 to 726 Second portion 731 to 736 Third portion

Claims

1. An electric compressor comprising: a compression mechanism for compressing a fluid; an electric motor for driving the compression mechanism; an inverter for controlling the drive of the electric motor; a housing for accommodating the compression mechanism and the electric motor; and a cover fixed to the housing by a plurality of fasteners and forming an accommodation chamber for accommodating the inverter between the housing and a cover, wherein the housing and the fasteners are made of metal; the cover is made of a vibration-damping steel plate having a first steel plate, a second steel plate arranged spaced apart from the first steel plate in the axial direction of the fasteners, and a resin material provided between the first steel plate and the second steel plate; the cover is formed with a plurality of insertion holes that penetrate from the first steel plate to the second steel plate in the axial direction and through which each of the fasteners is inserted; the housing is formed with a plurality of fixing holes that face each of the insertion holes and through which each of the fasteners is inserted and fixed; and each of the fasteners abuts against the first steel plate by fixing the cover to the housing, the second steel plate has a first surface facing the resin material and a second surface located opposite the first surface in the axial direction and facing the housing when the cover is fixed to the housing; the second surface has a plurality of first portions into which the insertion holes each open and a second portion located outside each of the first portions; the space between the second portion and the housing is sealed by a gasket; and at least one of the first portions is in direct contact with the housing.

2. The electric compressor according to claim 1, wherein each of said first portions directly contacts said housing.

3. The electric compressor according to claim 1 or 2, wherein said cover is fixed to said housing and covers a part of said housing from the outside.

4. An electric compressor as set forth in claim 3, wherein said second surface has a third portion which is connected to said second portion and covers the outer peripheral surface of said housing from the outside, and the gap between said third portion and said housing is sealed by said gasket.

5. An electric compressor as claimed in claim 1 or 2, wherein the first steel plate has a first plate body made of metal and a first plating layer covering the first plate body, the second steel plate has a second plate body made of metal and a second plating layer covering the second plate body, and the first plating layer and the second plating layer are corrosion resistant.

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