Electric compressor

Abstract

The present invention improves heat radiation performance of a noise filter circuit part and improves sticking workability of a heat radiation sheet to the noise filter circuit part in an inverter-integrated electric compressor. An electric compressor 1 includes: an inverter 6 including a noise filter circuit part 30 in which a plurality of electrolytic capacitors 51 are mounted in an upright state; a housing 5; an inverter housing part 7 for housing the inverter 6; and a cover member 8 for closing an opening part 75 thereof. The noise filter circuit part 30 includes a first case member 37 covering the electrolytic capacitor 51. One surface of a first case member 37 viewed from a mounting direction of the electrolytic capacitor 51 with respect to a circuit board 31 is formed in a polygonal shape connecting a contour of the electrolytic capacitor 51 by a straight line. A first heat radiation sheet 18 following the shape of one surface of the first case member 37 is arranged between the first case member 37 and the cover member 8.

Description

Electric compressor

[0001] The present invention relates to an electric compressor that compresses a refrigerant.

[0002] In an inverter-integrated electric compressor, a noise filter circuit including at least a plurality of electrolytic capacitors is attached to counter electromagnetic noise superimposed on the AC current supplied from the inverter to the electric motor. As described in Japanese Patent Laid-Open Publication No. 2013-36394 (Patent Document 1), in the noise filter circuit, the electrolytic capacitors are covered with a resin cover for seismic reinforcement, and a heat dissipation sheet is disposed between the resin cover and the housing to improve heat dissipation.

[0003] JP 2013-36394 A

[0004] The electric compressor described in Patent Document 1 uses a heat dissipation sheet that is larger than the top surface of the resin cover covering the electrolytic capacitor, resulting in portions that do not contribute to heat transfer from the noise filter circuit to the housing. To address this issue, a heat dissipation sheet that conforms to the shape of the top surface of the noise filter circuit could be considered. However, depending on the layout of the electrolytic capacitor, the shape of the heat dissipation sheet can become complex, making it difficult to determine the correct placement of the heat dissipation sheet relative to the top surface of the noise filter circuit, potentially resulting in misalignment or twisting. Such problems can reduce the efficiency of heat transfer from the noise filter circuit to the housing, potentially making it impossible to achieve the required heat dissipation performance.

[0005] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide an electric compressor in which the heat dissipation performance of a noise filter circuit is improved and the workability of attaching a heat dissipation sheet to the noise filter circuit is improved.

[0006] The electric compressor includes an electric motor, a rotating shaft rotated by the electric motor, a compression mechanism driven by the rotating shaft, an inverter including an inverter circuit for driving the electric motor and a noise filter circuit in which multiple electrolytic capacitors for reducing electromagnetic noise are mounted upright on a first circuit board, and a housing that accommodates the electric motor, the rotating shaft, and the compression mechanism. The electric compressor further includes an inverter accommodating section integral with the housing and having an opening for accommodating the inverter, and a cover member that closes the opening of the inverter accommodating section. The noise filter circuit section includes a first resin cover that covers the multiple electrolytic capacitors mounted on the first circuit board, and one surface of the first resin cover, as viewed from the mounting direction of the multiple electrolytic capacitors on the first circuit board, is formed into a polygon with straight lines connecting the contours of the multiple electrolytic capacitors. Furthermore, a first heat dissipation sheet conforming to the shape of the one surface of the first resin cover is disposed between the one surface of the first resin cover and one of the inner surfaces of the cover member and the bottom wall of the inverter accommodating section.

[0007] According to the present invention, in an inverter-integrated electric compressor, the heat dissipation performance of a noise filter circuit can be improved, and the workability of attaching a heat dissipation sheet to the noise filter circuit can be improved.

[0008] FIG. 1 is a longitudinal sectional view showing an example of an inverter-integrated electric compressor. FIG. 2 is a perspective view showing an example of an inverter and an inverter accommodating section. FIG. 3 is an exploded perspective view showing an example of a noise filter circuit section. FIG. 4 is a perspective view showing an example of a resin member. FIG. 5 is an enlarged sectional view of the periphery of a bus bar of the resin member. FIG. 6 is a longitudinal sectional view showing an example of an engaging member. FIG. 7 is a perspective view showing another example of an engaging member. FIG. 8 is a longitudinal sectional view showing another example of an engaging member. FIG. 9 is an explanatory diagram of a mold for integrally molding an engaging member. FIG. 10 is a plan view showing an example of a layout of a plurality of electrolytic capacitors. FIG. 11 is a perspective view showing an example of a noise filter circuit section and a heat dissipation sheet. FIG. 12 is a plan view showing a first modified example of the layout of a plurality of electrolytic capacitors. FIG. 13 is a plan view showing a second modified example of the layout of a plurality of electrolytic capacitors. FIG. 14 is a sectional view showing a modified example of a noise filter circuit section.

[0009] Hereinafter, with reference to the accompanying drawings, an embodiment for carrying out the present invention will be described in detail. Note that terms such as "first" and "second" used in the following description are used merely to distinguish between similar elements and do not limit the elements to which they are attached. Furthermore, the embodiment described below is merely an example and should not be construed as being limited to the configuration.

[0010] 1 shows an example of an inverter-integrated electric compressor 1 to which the present invention can be applied. The electric compressor 1 is incorporated in a refrigerant circuit (not shown) of an air conditioning device mounted on a vehicle, for example, and is configured to compress and discharge a refrigerant.

[0011] The electric compressor 1 has an electric motor 2, a rotating shaft 3 rotated by the electric motor 2, a compression mechanism 4 driven by the rotating shaft 3, a housing 5 that accommodates the electric motor 2, the rotating shaft 3, and the compression mechanism 4, an inverter 6 that drives and controls the electric motor 2, an inverter accommodating section 7, and a cover member 8.

[0012] The electric motor 2 is, for example, a three-phase synchronous motor such as a brushless DC motor, and is driven by power supplied from an inverter 6. The rotating shaft 3 is rotatably supported in a housing 5 by bearings (not shown), and is rotated by the electric motor 2. The housing 5 has a cylindrical cross section and houses the electric motor 2, the rotating shaft 3, and the compression mechanism 4. The electric motor 2, the rotating shaft 3, and the compression mechanism 4 are arranged concentrically inside the housing 5.

[0013] The inverter 6 includes an inverter circuit section 20 that drives the electric motor 2 and a noise filter circuit section 30 that reduces electromagnetic noise. The inverter accommodating section 7 is integrally formed with the housing 5 and accommodates the inverter 6 therein. Specifically, the inverter accommodating section 7 is provided on the electric motor 2 side of the housing 5. The inverter accommodating section 7 has a larger projected area than the housing 5. The inverter accommodating section 7 is formed by a bottom wall 71 and a peripheral wall 73 that rises from the periphery of the bottom wall 71, and has an opening 75 facing the bottom wall 71. When the inverter circuit section 20 and the noise filter circuit section 30 that constitute the inverter 6 are accommodated in the inverter accommodating section 7, the opening 75 of the inverter accommodating section 7 is closed by a cover member 8. The cover member 8 is fixed to the peripheral wall of the inverter accommodating section 7 (which is also part of the housing 5) with bolts (not shown).

[0014] An HV connector (high voltage connector) 9 is attached to the bottom wall 71 of the inverter accommodating portion 7 to supply DC power from an on-board battery (not shown) to the inverter circuit portion 20 of the inverter 6. A part of the bottom wall 71 of the inverter accommodating portion 7 forms a partition wall 77 that separates the interior of the housing 5 from the interior of the inverter accommodating portion 7.

[0015] The housing 5 is formed with an inlet 5a for allowing the refrigerant to flow into the housing 5 and an outlet 5b for allowing the refrigerant to flow out of the housing 5. The inlet 5a is configured to allow the refrigerant to flow into a space between the partition wall 77 inside the housing 5 and the electric motor 2. The refrigerant that flows into the housing 5 from the inlet 5a passes through the electric motor 2 and reaches the compression mechanism 4, where it is compressed by the compression mechanism 4. The refrigerant compressed by the compression mechanism 4 then flows out from the outlet 5b.

[0016] The refrigerant flowing into the housing 5 from the inlet 5 a is a low-temperature gas refrigerant that has passed through an expansion valve and an evaporator in a refrigerant circuit of an air conditioning device mounted on a vehicle. Therefore, the partition wall 77 and the electric motor 2 can be cooled by the refrigerant flowing into the housing 5 from the inlet 5 a.

[0017] The inverter 6 will be further described with reference to Figures 1 and 2. Figure 2 is a perspective view showing the inverter 6 and the inverter accommodating section 7. As described above, the inverter 6 includes the inverter circuit section 20 that drives the electric motor 2 and the noise filter circuit section 30 that reduces electromagnetic noise.

[0018] The inverter circuit unit 20 is configured to convert DC power supplied from the vehicle battery via the HV connector 9 into three-phase AC power and supply the power to the stator coil 2 a of the electric motor 2 via a power supply line 10 extending through the partition wall 77. To this end, the inverter circuit unit 20 includes six power switching elements 21 and an inverter control board 25 on which a control circuit 23 for controlling the six power switching elements 21 is mounted.

[0019] The six power switching elements 21 are placed on a sheet-like first heat dissipation member 11 that is installed on the surface of the partition wall 77 that faces the inverter accommodating section 7. Each of the six power switching elements 21 is fixed in a state in which it is pressed against the first heat dissipation member 11 by an arm member 12 (see FIG. 1 ). The arm member 12 is attached with a bolt 13 to an arm attachment portion 14 that is provided inside the inverter accommodating section 7.

[0020] The inverter control board 25 has a plurality of (seven in this example) mounting holes 25a. The inverter control board 25 is attached to a plurality of board mounting portions 15 provided inside the inverter accommodating portion 7 with a plurality of bolts (not shown). The inverter control board 25 is disposed near the cover member 8, i.e., spaced apart from the six power switching elements 21 (see FIG. 1 ). Therefore, each of the six power switching elements 21 has a lead wire extending toward the inverter control board 25, or more specifically, a lead wire extending through the inverter control board 25. These lead wires are soldered to the inverter control board 25, thereby electrically connecting the six power switching elements 21 and the inverter control board 25.

[0021] The noise filter circuit section 30 is disposed between the inverter circuit section 20 and the HV connector 9. FIG.

[0022] 1 and 3, the noise filter circuit unit 30 includes a first filter circuit board 31 and a second filter circuit board 33. The first filter circuit board 31 is an example of a first circuit board, and the second filter circuit board 33 is an example of a second circuit board.

[0023] To combat electromagnetic noise, a plurality of (here, nine) relatively large, cylindrical electrolytic capacitors 51 are mounted upright on one surface of the first filter circuit board 31. Note that this one surface of the first filter circuit board 31 is the top surface in Figures 1 and 3, and is the surface that faces the cover member 8 when the first filter circuit board 31 is housed in the inverter housing section 7.

[0024] Although not clearly shown in the drawings, the first filter circuit board 31 also has mounted thereon a plurality of electronic components that are smaller than the plurality of electrolytic capacitors 51. At least some of these small electronic components are mounted on the other surface of the first filter circuit board 31, more specifically, on the other surface of the first filter circuit board 31 in positions that avoid the area below the plurality of electrolytic capacitors 51. The other surface of the first filter circuit board 31 is the lower surface in FIGS. 1 and 3 , and is the surface that faces the bottom of the inverter accommodating section 7 when the first filter circuit board 31 is accommodated in the inverter accommodating section 7.

[0025] For electromagnetic noise countermeasures, a relatively large normal mode choke coil 53, a common mode choke coil 55, an X capacitor, and a Y capacitor (not shown) are mounted on one surface of the second filter circuit board 33. Note that this one surface of the second filter circuit board 33 is the bottom surface in Figures 1 and 3, and is the surface that faces the bottom of the inverter accommodating section 7 when the second filter circuit board 33 is accommodated in the inverter accommodating section 7. Here, the normal mode choke coil 53 and the common mode choke coil 55 are given as examples of coils.

[0026] Although not clearly shown in the drawings, a plurality of electronic components that are smaller than the normal mode choke coil 53, the common mode choke coil 55, the X capacitor, and the Y capacitor are also mounted on the second filter circuit board 33. At least some of these small electronic components are mounted on the other surface of the second filter circuit board 33, more specifically, in positions on the other surface of the second filter circuit board 33 that avoid the area below the normal mode choke coil 53, the common mode choke coil 55, the X capacitor, and the Y capacitor. The other surface of the second filter circuit board 33 is the top surface in FIGS. 1 and 3 , and is the surface that faces the cover member 8 when the second filter circuit board 33 is housed in the inverter accommodating section 7.

[0027] In the following, for the sake of simplicity, the normal mode choke coil 53, the common mode choke coil 55, the X capacitor, and the Y capacitor will be abbreviated as simply "the normal mode choke coil 53 and the common mode choke coil 55."

[0028] The first filter circuit board 31 and the second filter circuit board 33 are electrically connected to each other and are accommodated in the inverter accommodating section 7 in a state where the first filter circuit board 31 and the second filter circuit board 33 are stacked with the plate-shaped resin member 35 sandwiched between them. Specifically, the first filter circuit board 31 and the second filter circuit board 33 are electrically connected to each other and are accommodated in the inverter accommodating section 7 in a state where the other surface of the first filter circuit board 31 and the other surface of the second filter circuit board 33 are arranged back to back with the plate-shaped resin member 35 interposed between them. This will be described in detail below.

[0029] First, an example of the resin member 35 will be described with reference to Fig. 4. The resin member 35 includes a pair of bus bars 351 that electrically connect the first filter circuit board 31 and the second filter circuit board 33, a resin main body 352 that holds the pair of bus bars 351, and a metal shielding plate 41 that is disposed inside the main body 352 and blocks electromagnetic noise. In other words, the resin member 35 has the pair of bus bars 351 and incorporates the shielding plate 41. Specifically, the resin member 35 is formed as a plate-shaped resin molded body into which the pair of bus bars 351 and the shielding plate 41 are inserted. Furthermore, the resin member 35 is formed in a shape that follows (substantially matches) the outer shape of the first filter circuit board 31.

[0030] The main body 352 of the resin member 35 has peripheral edges 352a having a predetermined width, which are formed in a shape that protrudes on both sides in the thickness direction relative to an inner portion 352b. In other words, both sides of the main body 352, i.e., both surfaces of the resin member 35, are formed in a shape in which the inner portions 352b are recessed relative to the peripheral edges 352a.

[0031] The pair of bus bars 351 are arranged at a predetermined interval on the peripheral edge 352a of the main body 352. Each of the pair of bus bars 351 penetrates the peripheral edge 352a of the main body 352 in the thickness direction, and has a first protrusion 351a protruding from the peripheral edge 352a to one side in the thickness direction (upper side in FIGS. 1, 3, and 4) and a second protrusion 351b protruding from the peripheral edge 352a of the main body 352 to the other side in the thickness direction (lower side in FIGS. 1, 3, and 4).

[0032] 5 is a partially enlarged cross-sectional view of the resin member 35, showing the bus bar 351 and its surrounding area. The bus bar 351 is formed as a cross-shaped terminal. The bus bar 351 has a conductive portion 3511 for electrically connecting the first filter circuit board 31 and the second filter circuit board 33. The conductive portion 3511 extends through the peripheral edge portion 352a of the main body portion 352 in the thickness direction, and a held portion 3513 extends intersecting the conductive portion 3511 and is held by the main body portion 352. One end of the conductive portion 3511 forms a first protrusion 351a, and the other end of the conductive portion 3511 forms a second protrusion 351b.

[0033] Specifically, a through hole 353 penetrating the thickness direction is formed in a peripheral edge portion 352a of the main body portion 352, and the bus bar 351 is disposed in this through hole 353. The conductive portion 3511 of the bus bar 351 extends axially within the through hole 353, with one end protruding from one side of the through hole 353 (upper side in FIG. 5 ) as a first protrusion 351a and the other end protruding from the other side of the through hole 353 (lower side in FIG. 5 ) as a second protrusion 351b. The held portion 3513 extends in a direction perpendicular to the axial direction of the through hole 353, and both ends are embedded in the peripheral wall of the through hole 353, i.e., in the main body portion 352, thereby holding the held portion 3513, and therefore the bus bar 351, by the main body portion 352.

[0034] That is, only both ends of the held portion 3513 of the bus bar 351 are embedded in the main body portion 352 (i.e., the resin portion), and the other portions are exposed from the main body portion 352. Furthermore, the conductive portion 3511 of the bus bar 351 does not contact the peripheral wall of the through hole 353, i.e., the main body portion 352.

[0035] Although not particularly limited, the shielding plate 41 is formed in a shape that generally follows the shape of the inner portion 352b of the main body portion 352, as shown by the dashed lines in FIGS.

[0036] The first filter circuit board 31 is attached to the resin member 35 in a state where the other surface on which the plurality of electrolytic capacitors 51 are not mounted is placed and received on one surface (the upper surface in FIGS. 1, 3, and 4) of the resin member 35. Specifically, the first filter circuit board 31 is attached to the resin member 35 in a state where the other surface on which the plurality of electrolytic capacitors 51 are not mounted is placed on a peripheral portion 352a on one surface side of the main body 352 of the resin member 35.

[0037] A plurality of elastically deformable first engaging members 355 are integrated onto one surface of the resin member 35, protruding perpendicularly from this surface toward the first filter circuit board 31 and engaging by snap fit with a plurality (four in this case) of first engaging holes 311 (details of which will be described later) formed in the first filter circuit board 31. Specifically, the plurality of first engaging members 355 are erected on one surface of the main body portion 352 of the resin member 35 at intervals from one another in the circumferential direction of the peripheral edge portion 352 a thereof.

[0038] Further, a plurality of first engaging holes 311 are formed near the periphery of the first filter circuit board 31 at locations corresponding to the plurality of first engaging members 355 of the resin member 35 so as to receive these first engaging members 355. Each of the first engaging members 355 of the resin member 35 is inserted into and engaged with the first engaging holes 311 of the first filter circuit board 31, thereby fixing the first filter circuit board 31 to the resin member 35. Details of the first engaging members 355 will be described later.

[0039] The first filter circuit board 31 is formed with a pair of first busbar insertion holes 313 that receive the pair of busbars 351 of the resin member 35. The first protrusions 351 a of the pair of busbars 351 of the resin member 35 are inserted into the pair of first busbar insertion holes 313 of the first filter circuit board 31, and the first protrusions 351 a of the busbars 351 that protrude from the first busbar insertion holes 313 are solder-joined to the first filter circuit board 31. This electrically connects the pair of busbars 351 of the resin member 35 and the first filter circuit board 31.

[0040] As described above, the first protrusion 351a of the bus bar 351 is part of the conductive portion 3511 of the bus bar 351, and most of the conductive portion 3511 of the bus bar 351 is located inside the through hole 353 and is not in contact with the main body portion 352. Furthermore, in the bus bar 351, only both ends of the held portion 3513, which are located away from the first protrusion 351a, are embedded in the main body portion 352. This prevents the diffusion of heat generated when the first protrusion 351a is soldered to the first filter circuit board 31, resulting in stable solder quality. Furthermore, this also prevents the main body portion 352 from, for example, melting or deforming due to the heat generated when the first protrusion 351a is soldered to the first filter circuit board 31.

[0041] The pair of bus bars 351 of the resin member 35 may be provided with spring members (not shown) so that they are electrically connected by being press-fitted into the first bus bar insertion holes 313 of the first filter circuit board 31. In this way, soldering to establish the electrical connection between the bus bars 351 and the first filter circuit board 31 can be eliminated.

[0042] The second filter circuit board 33 is attached to the resin member 35 in a state where the other surface thereof, on which the normal mode choke coil 53 and the common mode choke coil 55 are not mounted, is placed on and supported by the other surface (the lower surface in FIGS. 1, 3, and 4) of the resin member 35. Specifically, the second filter circuit board 33 is attached to the resin member 35 in a state where the other surface thereof, on which the normal mode choke coil 53 and the common mode choke coil 55 are not mounted, is placed on a peripheral portion 352 a on the other surface side of the main body 352 of the resin member 35.

[0043] Similar to one surface of the resin member 35, the other surface of the resin member 35 is integrally formed with a plurality of elastically deformable second engaging members 356 that protrude perpendicularly from the other surface toward the second filter circuit board 33 and engage with a plurality (four in this example) of second engaging holes 331 (details of which will be described later) formed in the second filter circuit board 33 by snap-fitting. However, only two of the second engaging members 356 are shown in FIG. 4 . Specifically, the second engaging members 356 are erected on the other surface of the main body portion 352 of the resin member 35, spaced apart from one another in the circumferential direction of the peripheral edge portion 352 a. Here, the second engaging members 356 are disposed coaxially with the first engaging member 355 relative to the plate surface of the main body portion 352 of the resin member 35. In other words, the first engaging member 355 and the second engaging member 356 are disposed coaxially with the plate surface of the main body portion 352 of the resin member 35.

[0044] Further, a plurality of second engagement holes 331 are formed near the periphery of the second filter circuit board 33 at locations corresponding to the plurality of second engagement members 356 of the resin member 35 so as to receive these second engagement members 356. Each of the second engagement members 356 of the resin member 35 is inserted into and engages with the second engagement holes 331 of the second filter circuit board 33, thereby fixing the second filter circuit board 33 to the resin member 35. Details of the second engagement members 356 will be described later.

[0045] The second filter circuit board 33 is formed with a pair of second busbar insertion holes 333 that receive the pair of busbars 351 of the resin member 35. The second protrusions 351b of the pair of busbars 351 of the resin member 35 are inserted into the pair of second busbar insertion holes 333 of the second filter circuit board 33, and the second protrusions 351b of the busbars 351 that protrude from the second busbar insertion holes 333 are solder-joined to the second filter circuit board 33. This electrically connects the pair of busbars 351 of the resin member 35 and the second filter circuit board 33.

[0046] As described above, the second protrusion 351b of the bus bar 351 is part of the conductive portion 3511 of the bus bar 351, and most of the conductive portion 3511 of the bus bar 351 is located inside the through hole 353 and is not in contact with the main body portion 352. Furthermore, in the bus bar 351, only both ends of the held portion 3513, which are located away from the second protrusion 351b, are embedded in the main body portion 352. This prevents the diffusion of heat generated when the second protrusion 351b is soldered to the second filter circuit board 33, resulting in stable solder quality. Furthermore, this also prevents the main body portion 352 from, for example, melting or deforming due to the heat generated when the second protrusion 351b is soldered to the second filter circuit board 33.

[0047] 6 and 7 , the first engagement member 355 has two engagement claws 355a arranged axially symmetrically and extending perpendicular to the plate surface of the main body 352 of the resin member 35. Each of the two engagement claws 355a has a rectangular cross-sectional portion that rises perpendicularly from the plate surface of the main body 352 of the resin member 35 and a triangular tip portion TE1 that bulges outward from this portion. In a free state, the outer peripheral surfaces of the tip portions TE1 of the two engagement claws 355a are formed in a shape that follows the inner surface of the first engagement hole 311 of the first filter circuit board 31, that is, in an arc shape that follows the inner surface of the first engagement hole 311. Here, the free state refers to a state in which no external force other than gravity is acting on the first engagement member 355.

[0048] Therefore, in the process of the first engaging member 355 engaging with the first engaging hole 311, the entire surfaces of the tip ends TE1 of the two engaging claws 355a come into contact with the inner surface of the first engaging hole 311, and the force pressing the first engaging member 355 into the first engaging hole 311 elastically deforms the tip ends TE1 of the two engaging claws 355a so that they approach each other. Therefore, the force pressing the first engaging member 355 into the first engaging hole 311 can be efficiently used to easily and effortlessly engage the first engaging member 355 with the first engaging hole 311 of the first filter circuit board 31. Note that when the first engaging member 355 is completely engaged with the first engaging hole 311, the tip ends TE1 of the two engaging claws 355a penetrate the first engaging hole 311 and the two engaging claws 355a elastically return to their natural state, so the engagement between the two is not easily released. Here, when disengaging the first engagement member 355 from the first engagement hole 311 of the first filter circuit board 31, for example, an external force can be used to deform the tip ends TE1 of the two engagement claws 355a so that they approach each other, and in that state, the first engagement member 355 can be pulled out of the first engagement hole 311.

[0049] Furthermore, a base 355b that supports the first filter circuit board 31 is integrated with the base end of the first engaging member 355. The base 355b is not limited to a cylindrical shape as shown in Fig. 6, and can have any shape, such as a triangular prism or a square prism.

[0050] Like the first engaging member 355, the second engaging member 356 has two engaging claws 356a arranged axially symmetrically and extending perpendicular to the plate surface of the main body 352 of the resin member 35. Each of the two engaging claws 356a has a rectangular cross-sectional portion that rises perpendicularly from the plate surface of the main body 352 of the resin member 35 and a triangular tip portion TE2 that bulges outward from the rectangular cross-sectional portion. In a free state, the outer peripheral surfaces of the tip portions TE2 of the two engaging claws 356a are formed in a shape that conforms to the inner surface of the second engaging hole 331 of the second filter circuit board 33, that is, in an arc shape that conforms to the inner surface of the second engaging hole 331. In addition, a base 356b that supports the second filter circuit board 33 is integrated with the base end of the second engaging member 356. The base 356b is not limited to a cylindrical shape as shown in FIG. 6 and can have any shape, such as a triangular prism or a square prism. The action and effect of the second engaging member 356 are similar to those of the first engaging member 355, and therefore detailed description thereof will be omitted. Please refer to the action and effect of the first engaging member 355 if necessary.

[0051] The two engaging claws 355 a of the first engaging member 355 and the two engaging claws 356 a of the second engaging member 356 are arranged with a phase difference of 90° around an axis perpendicular to the plate surface of the main body 352 of the resin member 35. Therefore, when the first engaging member 355 engages with the first engaging hole 311 of the first filter circuit board 31 and the second engaging member 356 engages with the second engaging hole 331 of the second filter circuit board 33, the resin member 35 is positioned relative to the first filter circuit board 31 and the second filter circuit board 33.

[0052] Furthermore, when the first engaging member 355 and the second engaging member 356 are not arranged coaxially or when the noise filter circuit unit 30 includes only one circuit board, the first engaging member 355 (or the second engaging member 356) may be configured as follows. That is, as shown in FIG. 8 , the first engaging member 355 includes four engaging claws 355a arranged axially symmetrically and extending perpendicular to the plate surface of the main body 352 of the resin member 35. Other configurations of the first engaging member 355 are similar to those described above, and therefore detailed description thereof will be omitted. Here, the number of engaging claws 355a of the first engaging member 355 is not limited to four, but may be three, five, or more. In this way, when the first engaging member 355 engages with the first engaging hole 311 of the first filter circuit board 31 by snap-fitting, the first filter circuit board 31 and the resin member 35 can be positioned by the three or more engaging claws 355a of the first engaging member 355. The second engaging member 356 has a similar configuration to the first engaging member 355, and therefore a detailed description thereof will be omitted.

[0053] In the first engaging member 355 (similarly to the second engaging member 356) shown in FIG. 8 , no other engaging members are arranged coaxially across the resin member 35. Therefore, a die-cut hole 355c may be formed in the base 355b at a position overlapping the tip end TE1 of the engaging claw 355a when viewed from the direction perpendicular to the plate surface of the main body 352 of the resin member 35. As shown in FIG. 9 , the die-cut hole 355c penetrates from one surface to the other of the main body 352 of the resin member 35. In this way, when the first engaging member 355 is integrally molded using separable first and second molds MLD1 and MLD2, as shown in FIG. 10 , the first and second molds MLD1 and MLD2 can be released in one direction, in the direction in which the engaging claw 355a of the first engaging member 355 extends. This eliminates the need for a slide mold, which complicates the mold, and reduces mold costs.

[0054] In this way, the first filter circuit board 31 and the second filter circuit board 33 are integrated by the resin member 35, and the first filter circuit board 31 and the second filter circuit board 33 are electrically connected. Therefore, thermal caulking is not required when attaching the first filter circuit board 31 and the second filter circuit board 33 to the resin member 35, thereby preventing thermal effects on the first filter circuit board 31 and the second filter circuit board 33. Furthermore, as described above, by devising the shapes of the tip portions of the first engaging member 355 and the second engaging member 356, engagement with the first engaging hole 311 of the first filter circuit board 31 and the second engaging hole 331 of the second filter circuit board 33 can be easily and effortlessly performed. For these reasons, the first filter circuit board 31 and the second filter circuit board 33 can be prevented from being damaged when they are positioned and fixed to the resin member 35.

[0055] The noise filter circuit unit 30 further includes a first case member 37 and a second case member 39. Here, the first case member 37 is an example of a first resin cover, and the second case member 39 is an example of a second resin cover.

[0056] The first case member 37 is formed of, for example, a hard resin. The first case member 37 is attached to one surface of the first filter circuit board 31, and is configured to house and cover the nine electrolytic capacitors 51 mounted on one surface of the first filter circuit board 31. The first case member 37 is attached to one surface of the first filter circuit board 31 in the following manner.

[0057] First, a predetermined amount of resin R in a softened or molten state is filled into the first case member 37. Next, while the first filter circuit board 31 and the first case member 37 are aligned, the first case member 37 is pressed against one surface of the first filter circuit board 31. The first filter circuit board 31 and the first case member 37 are aligned by inserting two pins (not shown) provided on the first case member 37 into the pin insertion holes 315a and the elongated pin insertion holes 315b formed in the first filter circuit board 31. The resin R filled into the first case member 37 is then hardened. In this manner, the first case member 37 is fixed to one surface of the first filter circuit board 31. Furthermore, gaps within the first case member 37, i.e., gaps between the multiple electrolytic capacitors 51 and gaps between the electrolytic capacitors 51 and the first case member 37, are filled with the resin R. Note that the resin R is preferably a heat-resistant thermoplastic resin or a thermosetting resin.

[0058] Here, the top surface of the first case member 37, i.e., the surface located distal from the first filter circuit board 31, is formed in a shape corresponding to the layout of the nine electrolytic capacitors 51 mounted on one surface of the first filter circuit board 31. As shown in Fig. 11 , the nine electrolytic capacitors 51 are divided into three rows of three groups, and the groups on either side of the middle group are arranged at positions offset by half the spacing between two adjacent electrolytic capacitors 51 in the middle group. In this case, one surface of the first case member 37, as viewed from the mounting direction of the plurality of electrolytic capacitors 51 on the first filter circuit board 31, is formed into a pentagon in which the outlines of the plurality of electrolytic capacitors 51 are connected by straight lines.

[0059] In short, the layout of the nine electrolytic capacitors 51 should be devised so that one surface of the first case member 37, as viewed from the mounting direction of the electrolytic capacitors 51 on the first filter circuit board 31, is formed into a pentagon with straight lines connecting the outlines of the electrolytic capacitors 51. The same applies to other layouts of the nine electrolytic capacitors 51 (details of which will be described later).

[0060] The second case member 39 is formed of, for example, hard resin, similar to the first case member 37. The second case member 39 is attached to the other surface of the second filter circuit board 33, and is configured to house and cover the normal mode choke coil 53 and the common mode choke coil 55 mounted on one surface of the second filter circuit board 33. Similarly to the first case member 37, the second case member 39 is attached to one surface of the second filter circuit board 33 in the following manner.

[0061] First, a predetermined amount of resin R in a softened or molten state is filled into the second case member 39. Next, while the second filter circuit board 33 and the second case member 39 are aligned, the second case member 39 is pressed against one surface of the second filter circuit board 33. The second filter circuit board 33 and the second case member 39 are aligned by inserting two pins 391 provided on the second case member 39 into the pin insertion holes 335a and the elongated pin insertion holes 335b formed in the second filter circuit board 33. The resin R filled into the second case member 39 is then hardened. In this manner, the second case member 39 is fixed to one surface of the second filter circuit board 33. Furthermore, gaps within the second case member 39, i.e., gaps between components such as the normal mode choke coil 53 and the common mode choke coil 55 and gaps between these components and the second case member 39, are filled with the resin R.

[0062] In this way, the first filter circuit board 31 and the second filter circuit board 33 are integrated via the resin member 35, and the first case member 37 and the second case member 39 are also integrated. That is, the noise filter circuit section 30 includes the first filter circuit board 31, the second filter circuit board 33, the resin member 35, the first case member 37, and the second case member 39, and these are integrated to form a module.

[0063] The noise filter circuit section 30 is fixed to a filter mounting section 17 provided inside the inverter accommodating section 7 by a plurality of bolts 16 (only one of which is shown in FIG. 1).

[0064] Specifically, a plurality of (here, four) corresponding mounting holes are formed in each of the first filter circuit board 31, the second filter circuit board 33, the resin member 35, the first case member 37, and the second case member 39. That is, four first mounting holes 317 are formed in the first filter circuit board 31, and four second mounting holes 337 are formed in the second filter circuit board 33. Furthermore, four third mounting holes 357 are formed in the resin member 35, four fourth mounting holes 371 are formed in the first case member 37, and four fifth mounting holes 393 are formed in the second case member 39. Here, the third mounting holes 357, the fourth mounting holes 371, and the fifth mounting holes 393 may be formed by metallic cylindrical sleeves inserted during molding.

[0065] The noise filter circuit unit 30 is accommodated in the inverter accommodating unit 7 with the second case member 39 facing the bottom of the inverter accommodating unit 7. Then, bolts 16 are inserted through the fourth mounting hole 371 of the first case member 37, the first mounting hole 317 of the first filter circuit board 31, the third mounting hole 357 of the resin member 35, the second mounting hole 337 of the second filter circuit board 33, and the fifth mounting hole 393 of the second case member 39, in this order, and then screwed into threaded holes formed in the filter mounting portion 17. In this way, the first filter circuit board 31, the second filter circuit board 33, the resin member 35, the first case member 37, and the second case member 39 are fixed integrally within the inverter accommodating unit 7.

[0066] After the installation of the inverter circuit section 20 and the noise filter circuit section 30 in the inverter accommodating section 7 is completed, the cover member 8 is attached to the peripheral wall 73 of the inverter accommodating section 7 .

[0067] As shown in FIG. 12 , a first heat dissipation sheet 18 is attached to one surface of the first case member 37 of the noise filter circuit unit 30 to increase the amount of heat transferred from the noise filter circuit unit 30 to the cover member 8, thereby improving heat dissipation. If one surface of the first case member 37 is pentagonal as shown in FIG. 11 , the first heat dissipation sheet 18 attached thereto can also be pentagonal. That is, the shape of the first heat dissipation sheet 18 can be modeled after the shape of the one surface of the first case member 37. This simplifies the shape of the first heat dissipation sheet 18, thereby reducing the amount of waste when cutting multiple first heat dissipation sheets 18 from a large heat dissipation sheet. Furthermore, because the two corners of the pentagon are at 90° angles, the reference position for attaching the first heat dissipation sheet 18 to the first case member 37 is clear, making the attachment work easier for workers and enabling automation of the attachment work using robots, etc.

[0068] A second heat dissipation sheet 19 is attached to one surface of the second case member 39 of the noise filter circuit unit 30, i.e., the surface facing the bottom of the inverter accommodating unit 7, to improve heat dissipation by increasing the amount of heat transferred from the noise filter circuit unit 30 to the bottom of the inverter accommodating unit 7. The second heat dissipation sheet 19 can be shaped to match the shape of one surface of the second case member 39.

[0069] In this way, the noise filter circuit unit 30 is sandwiched between the bottom of the inverter accommodating unit 7 and the cover member 8, with the first heat dissipation sheet 18 interposed between the first case member 37 and the cover member 8 and the second heat dissipation sheet 19 interposed between the second case member 39 and the bottom of the inverter accommodating unit 7. Therefore, heat generated in the noise filter circuit unit 30 is efficiently transferred via the first heat dissipation sheet 18 and the second heat dissipation sheet 19 to the cover member 8 and the bottom of the inverter accommodating unit 7 and dissipated from the outer surfaces thereof, thereby improving the heat dissipation performance of the noise filter circuit unit 30. At this time, the bottom wall 71 is cooled by the refrigerant flowing into the housing 5 from the inlet 5a, thereby further improving the heat dissipation performance of the noise filter circuit unit 30.

[0070] One surface of the first case member 37 of the noise filter circuit unit 30 is not limited to a pentagon, and may be a polygon as shown in Figures 13 and 14. In short, the layout of the nine electrolytic capacitors 51 may be devised so that one surface of the first case member 37, as viewed from the mounting direction of the electrolytic capacitors 51 on the first filter circuit board 31, is formed into a polygon in which the outlines of the electrolytic capacitors 51 are connected by straight lines.

[0071] As shown in FIG. 13 , if the nine electrolytic capacitors 51 mounted on one surface of the first filter circuit board 31 are arranged within the range of a trapezoid, one surface of the first case member 37 can be formed into a trapezoidal shape that imitates this. Furthermore, as shown in FIG. 14 , if the nine electrolytic capacitors 51 arranged on one surface of the first filter circuit board 31 are arranged within the range of a parallelogram, one surface of the first case member 37 can be formed into a parallelogram that imitates this. However, in the case of a parallelogram shape as shown in FIG. 14 , it is desirable that, for example, two acute corners have a 90° angle to clearly indicate the reference for attaching the first heat dissipation sheet 18 to the first case member 37. Although not shown, if the nine electrolytic capacitors 51 mounted on one surface of the first filter circuit board 31 are arranged within the range of a square, one surface of the first case member 37 can be formed into a square that imitates this.

[0072] In other words, by devising a layout of the multiple electrolytic capacitors 51, one surface of the first case member 37 can be made into a polygon having at least two 90° corners. When one surface of the first case member 37 is formed into a polygon having at least two 90° corners, the first heat dissipation sheet 18 attached thereto can be shaped to resemble that polygon.

[0073] In addition to the above-described advantages, the electric compressor 1 according to this embodiment can also achieve the following advantages.

[0074] In the electric compressor 1, the noise filter circuit section 30 includes a first filter circuit board 31 on which a plurality of electrolytic capacitors 51 are mounted, and a second filter circuit board 33 on which a normal mode choke coil 53 and a common mode choke coil 55 are mounted. The first filter circuit board 31 and the second filter circuit board 33 are electrically connected to each other and are housed in the inverter housing section 7 in a state where they are stacked back to back with a plate-shaped resin member 35 sandwiched between them.

[0075] That is, a plurality of electrolytic capacitors 51, normal mode choke coils 53, and common mode choke coils 55 for electromagnetic noise countermeasures are mounted in a distributed manner on the first filter circuit board 31 and the second filter circuit board 33, and the first filter circuit board 31 and the second filter circuit board 33 are arranged above and below each other with the resin member 35 sandwiched therebetween. Therefore, even if the noise filter circuit unit 30 is increased in size or the number of components is increased, an increase in the projected area of ​​the filter circuit boards constituting the noise filter circuit unit 30, in other words, an increase in the projected area of ​​the inverter accommodating section 7, is suppressed. This also suppresses restrictions on the installation location of the electric compressor 1 and an increase in noise caused by vibration of the cover member 8. Furthermore, because the plurality of electrolytic capacitors 51, the normal mode choke coil 53, and the common mode choke coil 55 are mounted on separate circuit boards, thermal interference therebetween is suppressed.

[0076] In particular, a plurality of electrolytic capacitors 51 are mounted on one surface of the first filter circuit board 31, and a normal mode choke coil 53 and a common mode choke coil 55 are mounted on one surface of the second filter circuit board 33. The first filter circuit board 31 and the second filter circuit board 33 are housed in the inverter housing section 7 with the other surface of each board facing each other with the resin member 35 in between. Therefore, the first filter circuit board 31 and the second filter circuit board 33 are each reinforced by the plate-shaped resin member 35, which improves the earthquake resistance of the filter circuit boards, in other words, the noise filter circuit section 30.

[0077] Furthermore, the resin member 35 has a pair of metal bus bars 351 that electrically connect the first filter circuit board 31 and the second filter circuit board 33, and also incorporates a shielding plate 41 that blocks electromagnetic noise. This eliminates the need to separately provide components that electrically connect the first filter circuit board 31 and the second filter circuit board 33, and enables a compact and stable connection between the first filter circuit board 31 and the second filter circuit board 33. As a result, malfunctions due to interference from radiated noise between the first filter circuit board 31 and the second filter circuit board 33 are prevented.

[0078] Furthermore, the resin member 35 has a shape that follows the outer shape of the first filter circuit board 31. Therefore, the resin member 35 functions as an insulating wall between the first filter circuit board 31 and the second filter circuit board 33, and an insulating distance between the first filter circuit board 31 and the second filter circuit board 33 can be ensured.

[0079] The first filter circuit board 31 is fixed to one surface of the resin member 35 by a first engaging member 355, and the second filter circuit board 33 is fixed to the other surface of the resin member 35 by a second engaging member 356. Therefore, the first filter circuit board 31 and the second filter circuit board 33 can be integrated into a module, and deterioration in the ease of attaching the noise filter circuit unit 30 to the inverter accommodating unit 7 due to multiple filter components being distributed and mounted on two circuit boards is suppressed.

[0080] Furthermore, mounting space for small electronic components mounted on the other surface of the first filter circuit board 31 is secured by the first filter circuit board 31 being received by the seats 355b of the first engaging member 355. Mounting space for small electronic components mounted on the other surface of the second filter circuit board 33 is secured by the second filter circuit board 33 being received by the seats 356b of the second engaging member 356. Therefore, by appropriately setting the heights of the seats 355b of the first engaging member 355 and the seats 356b of the second engaging member 356 in accordance with the small electronic components, the noise filter circuit unit 30 can be miniaturized while securing mounting space for the small electronic components.

[0081] 15 , in the noise filter circuit section 30, a third heat dissipation sheet 43 may be disposed between the first filter circuit board 31 and the resin member 35, and a fourth heat dissipation sheet 45 may be further disposed between the second filter circuit board 33 and the resin member 35. In this case, the third heat dissipation sheet 43 and the fourth heat dissipation sheet 45 may each be shaped to cover at least the area of ​​the heat-generating electronic components. In this way, heat generated in the multiple electrolytic capacitors 51, the normal mode choke coil 53, and the common mode choke coil 55 can be efficiently dissipated.

[0082] In the above embodiment, the housing 5 and the inverter accommodating portion 7 are integrally molded, but it is sufficient that the inverter accommodating portion 7 is provided integrally with the housing 5. For example, the housing 5 and the inverter accommodating portion 7 may be formed separately and then combined into an integrated body.

[0083] In the above embodiment, a plurality of electrolytic capacitors 51 are mounted on one surface of the first filter circuit board 31, and a normal mode choke coil 53 and a common mode choke coil 55 are mounted on one surface of the second filter circuit board 33. However, this configuration is not limited to this. The normal mode choke coil 53 and the common mode choke coil 55 may be mounted on one surface of the first filter circuit board 31, and a plurality of electrolytic capacitors 51 may be mounted on one surface of the second filter circuit board 33. However, if this configuration is adopted, the other surface of the second case member 39 of the noise filter circuit unit 30, i.e., the surface facing the bottom of the inverter accommodating portion 7, must be formed in a polygonal shape corresponding to the arrangement of the plurality of electrolytic capacitors 51. In addition, the first heat dissipation sheet 18 is disposed between the first case member 37 and the bottom of the inverter accommodating portion 7, and the second heat dissipation sheet 19 is disposed between the second case member 39 and the cover member 8.

[0084] Furthermore, in the above embodiment, the resin member 35 has a pair of metal bus bars 351 that electrically connect the first filter circuit board 31 and the second filter circuit board 33, and also has a built-in metal shielding plate 41 that blocks electromagnetic noise. However, the present invention is not limited to this configuration, and the first filter circuit board 31 and the second filter circuit board 33 may be electrically connected by a component other than the bus bars 351, and the shielding plate 41 may be omitted if the level of electromagnetic noise is relatively low.

[0085] Furthermore, in the above embodiment, the resin member 35 is formed in a shape that follows the outer shape of the first filter circuit board 31. However, the present invention is not limited to this configuration, and the resin member 35 may be formed in a shape that follows the outer shape of at least one of the first filter circuit board 31 and the second filter circuit board 33. Preferably, the first filter circuit board 31, the second filter circuit board 33, and the resin member 35 are formed so that their outer shapes approximately match.

[0086] Additionally, in the above embodiment, nine electrolytic capacitors 51 are mounted on the first filter circuit board 31 of the noise filter circuit section 30, but the number of electrolytic capacitors 51 is not limited to nine and may be any plural number. However, the plurality of electrolytic capacitors 51 must be accommodated within a polygon whose outline is connected by straight lines, specifically, a polygon with at least two corners at 90°.

[0087] Those skilled in the art will readily understand that new embodiments can be created by omitting parts of the technical ideas of the various above-described embodiments, combining parts of the ideas appropriately, or replacing parts of the ideas with well-known technology.

[0088] DESCRIPTION OF SYMBOLS 1...electric compressor, 2...electric motor, 3...rotating shaft, 4...compression mechanism, 5...housing, 6...inverter, 7...inverter accommodating section, 8...cover member, 18...first heat dissipation sheet, 19...second heat dissipation sheet, 20...inverter circuit section, 30...noise filter circuit section, 31...first filter circuit board (first circuit board), 33...second filter circuit board (second circuit board), 35...resin member, 37...first case member (first resin cover), 39...second case member (second resin cover), 51...electrolytic capacitor, 53...normal mode choke coil (coil), 55...common mode choke coil (coil), 75...opening, 351...bus bar

Claims

1. An electric compressor having: an electric motor; a rotating shaft rotated by the electric motor; a compression mechanism driven by the rotating shaft; an inverter including an inverter circuit section that drives the electric motor, and a noise filter circuit section in which a plurality of electrolytic capacitors for reducing electromagnetic noise are mounted in an upright state on a first circuit board; a housing that accommodates the electric motor, the rotating shaft, and the compression mechanism; an inverter accommodating section that is formed integrally with the housing and has an opening for accommodating the inverter; and a cover member that closes the opening of the inverter accommodating section, wherein the noise filter circuit section includes a first resin cover that covers the plurality of electrolytic capacitors mounted on the first circuit board, one side of the first resin cover as viewed from the mounting direction of the plurality of electrolytic capacitors on the first circuit board is formed into a polygon formed by connecting outlines of the plurality of electrolytic capacitors with straight lines, and a first heat dissipation sheet following the shape of one side of the first resin cover is arranged between the one side of the first resin cover, an inner surface of the cover member, and one side of a bottom wall of the inverter accommodating section.

2. The electric compressor according to claim 1, wherein the polygon formed on one surface of the first resin cover has at least two corners each having an angle of 90°.

3. The electric compressor according to claim 1, wherein the first heat dissipation sheet is attached to one surface of the first resin cover.

4. The electric compressor as claimed in claim 1, wherein the noise filter circuit section further includes: a second circuit board on which at least one coil is mounted; a second resin cover covering the at least one coil mounted on the second circuit board; a resin member arranged between the first circuit board and the second circuit board with the multiple electrolytic capacitors and the at least one coil facing in opposite directions; and a second heat dissipation sheet arranged between one side of the second resin cover as viewed from the mounting direction of the at least one coil on the second circuit board and an inner surface of the cover member and the other side of the bottom wall of the inverter accommodating section.

5. The electric compressor according to claim 4, wherein the resin member includes a bus bar that electrically connects the first circuit board and the second circuit board.

6. The electric compressor according to claim 1, wherein the first heat dissipation sheet is disposed between one surface of the first resin cover and an inner surface of the cover member.

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