Electric compressor

Abstract

This electric compressor (10) comprises an inverter (13) that controls an electric motor. The inverter (13) is provided with a plurality of switching elements (40), and a printed circuit board (50) on which the plurality of switching elements (40) are mounted. The plurality of switching elements (40) are positioned between the printed circuit board (50) and a cooling wall (24). A first frame (80), which is positioned between the printed circuit board (50) and the plurality of switching elements (40), biases the plurality of switching elements (40) toward the cooling wall (24). A second frame (90), which is attached to the first frame (80), holds the plurality of switching elements (40).

Description

Electric compressor

[0001] The present invention relates to an improved technology for an electric compressor including a compression mechanism for compressing a fluid, an electric motor for driving the compression mechanism, and an inverter for controlling the electric motor.

[0002] In recent years, as a compressor constituting a refrigeration cycle of a vehicle air conditioner, an electric compressor in which a compression mechanism, a motor for driving the compression mechanism, and an inverter for controlling the drive of the motor are integrally configured is known. High-voltage DC power and low-voltage control signals are supplied to the inverter from the outside of the compressor. In order to convert the high-voltage DC power into three-phase AC power for driving the motor, the inverter is provided with switching elements such as IGBTs.

[0003] Since heat is generated when the switching element converts DC to AC, it is necessary to attach a heat sink or the like to dissipate the heat. In an electric compressor used in a vehicle air conditioner, it is common to use the motor housing for storing the motor as a low-pressure and low-temperature suction refrigerant passage. It is also well known to cool the heat generated by the switching element with the low-temperature suction refrigerant by pressing the switching element against a partition wall (bottom wall) separating the inverter housing and the motor housing.

[0004] Several structures have been proposed as methods for pressing the switching element against the housing partition wall or a cooling plate attached to the housing partition wall. For example, the techniques of Patent Documents 1 to 3 are known.

[0005] The electric compressor known from Patent Document 1 fastens the switching element to the housing by inserting a bolt through a through-hole provided in the switching element.

[0006] The electric compressor known from Patent Document 2 fixes a holder member provided so as to be provided in parallel with the switching element to the housing with screws. The holder member has a leaf spring portion that covers the upper surface of the switching element, and biases the switching element against the housing by the elastic force of the leaf spring portion. [[ID=二十]]

[0007] The electric compressor known from Patent Document 3 includes a guide member between the printed circuit board and the switching element, and a spring member positioned between the guide member and the switching element biases the switching element toward the housing.

[0008] Japanese Patent Publication No. 2020-198713, Japanese Patent Publication No. 2022-551235, Japanese Patent Publication No. 2013-026320

[0009] However, in the electric compressor known from Patent Document 1, the bolts screwed into the housing are conductive materials, so it is necessary to ensure a sufficient creepage distance from the part where the high voltage of the switching element is applied. Therefore, measures such as providing an insulating tube between the bolt and the insertion hole are required, which has the disadvantage of increasing the number of parts.

[0010] In the electric compressor known from Patent Document 2, the holder member requires a fastening portion to the housing at a position that does not project onto the switching element. As a result, the holder becomes larger, and the housing also requires space for fastening bolts, which is disadvantageous in terms of compactness.

[0011] In the electric compressor known from Patent Document 3, a guide member is fastened to the housing (cooling member) with screws, a printed circuit board is then attached, and then the leads of the switching element are soldered to the printed circuit board. If a malfunction is found in the IGBT during a power-on test after assembly, it is not possible to replace the IGBT because the guide member is fastened to the housing with screws under the printed circuit board, making it impossible to remove the guide member and replace the IGBT.

[0012] The present invention was made to solve the above-mentioned problems, and aims to provide an inverter for an electric compressor using multiple switching elements that has a small number of parts, is compact, and has advantages in terms of ease of assembly and disassembly.

[0013] In the following description, reference numerals in the accompanying drawings are indicated in parentheses to facilitate understanding of the present invention; however, this does not mean that the present invention is limited to the illustrated forms.

[0014] According to this disclosure, an electric compressor (10) includes a compression mechanism (11) for compressing a refrigerant, an electric motor (12) for driving the compression mechanism (11), an inverter (13) for controlling the electric motor (12), a motor housing chamber (22a) for housing the electric motor (12), an inverter housing chamber (23a) for housing the inverter (13), and a cooling wall (24) that partitions the motor housing chamber (22a) and the inverter housing chamber (23a) and is cooled by the refrigerant flowing through the motor housing chamber (22a), wherein the inverter (13) comprises a plurality of switching elements (40) for controlling the driving of the electric motor (12), and a printed circuit board (50) on which the plurality of switching elements (40) can be mounted, and the plurality of switching elements (40) are located between the printed circuit board (50) and the cooling wall (24), An electric compressor is provided, comprising: a first frame (80) positioned between the printed circuit board (50) and the plurality of switching elements (40), which biases the plurality of switching elements (40) toward the cooling wall (24); and a second frame (90) attached to the first frame (80) for holding the plurality of switching elements (40).

[0015] Preferably, the printed circuit board (50) has a plurality of lead connection holes (53) to which the plurality of leads (42) of the plurality of switching elements (40) are connected, and the second frame (90) holds the plurality of switching elements (40) such that the positions of the plurality of leads (42) correspond to the positions of the plurality of lead connection holes (53).

[0016] More preferably, the second frame (90) has a plurality of lead insertion holes (120) through which the plurality of leads (42) are inserted at positions corresponding to the plurality of lead connection holes (53), and the plurality of switching elements (40) are positioned on the second frame (90) by inserting the plurality of leads (42) through the plurality of lead insertion holes (120).

[0017] More preferably, the first frame (80) has a plurality of lead straightening holes (151) through which the plurality of leads (42) are inserted, at positions corresponding to the plurality of lead connection holes (53), and the positions of the plurality of leads (42) are straightened to match the plurality of lead connection holes (53) by inserting the plurality of leads (42) through the plurality of lead straightening holes (151).

[0018] In another preferred example, the first frame (80) is attached to the printed circuit board (50).

[0019] In yet another preferred example, the electric compressor (10) further has a mounting portion (24b) erected from the cooling wall (24) toward the first frame (80), the first frame (80) having a mounting portion (86) sandwiched between the printed circuit board (50) and the mounting portion (24b), the printed circuit board (50) and the mounting portion (86) being fastened to the mounting portion (24b) by a common fastening member (87).

[0020] In another preferred example, the first frame (80) has a plurality of biasing portions (140) that contact the plurality of switching elements (40) and bias the cooling wall (24), and the plurality of biasing portions (140) are formed from a part of the first frame (80).

[0021] Preferably, the second frame (90) is located between the first frame (80) and the cooling wall (24), and has a frame portion (110) surrounding the plurality of switching elements (40), the frame portion (110) having an opening (144) through which the plurality of biasing portions (140) of the first frame (80) can be inserted and contact the plurality of switching elements (40).

[0022] Preferably, the plurality of leads (42) extend from the side surface (41c) of each switching body (41) of the plurality of switching elements (40) and have an L-shaped configuration, bent toward the plurality of lead insertion holes (120) of the second frame (90), and are held in place by the second frame (90) by an electrically insulating and flexible potting material (131).

[0023] More preferably, the first frame (80) has a plurality of recesses (152) into which the plurality of leads (42) are individually inserted, the plurality of recesses (152) communicate with the plurality of lead straightening holes (151), and the plurality of inner wall surfaces (152a) forming the plurality of recesses (152) increase the creepage distance (L2) between adjacent leads (42) relative to the spatial distance (L1) between adjacent leads (42).

[0024] More preferably, the inner wall surface (152a) that forms the recess (152) is tapered from the switching element (40) side toward the lead straightening hole (151).

[0025] In this invention, an inverter for an electric compressor using multiple switching elements can be provided with a small number of parts, a compact structure, and a structure that is advantageous in terms of ease of assembly and disassembly.

[0026] This is a cross-sectional view of the electric compressor according to the embodiment, taken along the motor shaft of the electric motor. This is an enlarged view of part 2 of Figure 1. This is an enlarged view of part 3 of Figure 2. This is a perspective view of the inverter unit shown in Figure 2, viewed from the cooling wall side, with some switching elements separated. This is an enlarged view of part 5 of Figure 4. This is an exploded view of the inverter unit and cooling wall shown in Figure 2, viewed from the printed circuit board side. This is an enlarged view of the inverter unit shown in Figure 6. This is a cross-sectional view along line 8-8 in Figure 3.

[0027] Embodiments of the present invention will be described below with reference to the attached drawings. Note that the embodiments shown in the attached drawings are examples of the present invention, and the present invention is not limited to these embodiments.

[0028] <Example> As shown in Figure 1, the electric compressor 10 is configured as a so-called horizontal electric compressor that can be installed horizontally, for example. This electric compressor 10 includes a compression mechanism 11 for compressing a fluid (refrigerant gas), an electric motor 12 for driving the compression mechanism 11, and an inverter 13 for controlling the electric motor 12. Furthermore, the electric compressor 10 includes a compression housing 21 having a compressor housing chamber 21a in which the compression mechanism 11 is housed, a motor housing 22 having a motor housing chamber 22a in which the electric motor 12 is housed, and an inverter housing 23 having an inverter housing chamber 23a in which the inverter 13 is housed.

[0029] The compression housing 21, motor housing 22, and inverter housing 23 are arranged in this order in the axial direction of the output shaft 12a of the electric motor 12 (along the centerline CL of the output shaft 12a). These three housings 21, 22, and 23 are made of a metal material such as aluminum (including aluminum alloy), and may be all a single unit, all separate units, or any two of them integrated. The motor housing chamber 22a and the inverter housing chamber 23a are separated by a partition wall 24. This partition wall 24 is configured to be cooled by the coolant flowing through the motor housing chamber 22a, and its form is arbitrary. The partition wall 24 may be referred to as a "cooling wall 24" as appropriate.

[0030] For example, the partition wall 24 (cooling wall 24) can have one of the following configurations. In the first example configuration, as shown in Figure 1, the motor housing 22 does not have a bottom wall (it is an open end), and the partition wall 24 is formed only by the bottom wall of the inverter housing 23. In the second example configuration, the bottom wall of the motor housing 22 and the bottom wall of the inverter housing 23 are in contact, and the partition wall 24 is formed by both bottom walls. In the third example configuration, the motor housing 22, the inverter housing 23, and the partition wall 24 are integrally formed. In the fourth example configuration, the inverter housing 23 does not have a bottom wall (it is an open end), and the partition wall 24 is formed only by the bottom wall of the motor housing 22.

[0031] The open end 23b of the inverter housing 23 (the end 23b opposite to the partition wall 24) is closed by an openable and closable cover 25. The inverter housing 23 and the cover 25 constitute the inverter housing chamber 23a. Furthermore, the inverter housing 23 is equipped with a connector 26 for supplying control signals and power to the inverter 13. The side 24a of the cooling wall 24 facing the inverter housing chamber 23a is sometimes called the "element mounting surface 24a". This element mounting surface 24a is formed as a flat surface.

[0032] The compression mechanism 11 compresses the refrigerant gas drawn into the compression housing 21 from an air conditioning cycle (not shown) via the motor housing 22, and is configured, for example, by a scroll compression mechanism. This compression mechanism 11 compresses the refrigerant by combining a fixed scroll 11a, which is positioned in the compressor housing chamber 21a with its relative rotation restricted, and an orbiting scroll 11b, which can swing circumferentially relative to the fixed scroll 11a.

[0033] The electric motor 12 is configured as, for example, a three-phase AC brushless motor. This electric motor 12 comprises an output shaft 12a (motor shaft 12a), a rotor 12b fixed to the output shaft 12a, and a cylindrical stator 12c surrounding the rotor 12b.

[0034] As the output shaft 12a of the electric motor 12 rotates, the oscillating scroll 11b revolves. The refrigerant drawn in from the intake port 31 of the motor housing 22 flows along the partition wall 24 (cooling wall 24), cooling the partition wall 24, and passing through the gap of the electric motor 12 in the motor housing chamber 22a, removing the heat generated by the electric motor 12 before being taken into the compression chamber 11c of the compression mechanism 11. As the oscillating scroll 11b revolves, the compression chamber 11c gradually moves toward the center while its internal volume decreases. As a result, the refrigerant in the compression chamber 11c is compressed. When the pressure in the compression chamber 11c rises to exceed the pressure required to open the discharge valve 11d, the discharge valve 11d opens due to the pressure difference. The refrigerant in the compression chamber 11c flows into the discharge chamber 32 through the discharge hole 11e. The refrigerant in the discharge chamber 32 is discharged outward from the discharge port 34 via the oil separator 33.

[0035] Next, the inverter 13 will be described in detail. As shown in Figures 2 and 3, the inverter 13 includes a plurality (for example, six) of switching elements 40 that control the drive of the electric motor 12 (see Figure 1), and a printed circuit board 50 on which these switching elements 40 can be mounted. Of the two sides 51 and 52 of this printed circuit board 50, the side 51 facing the element mounting surface 24a of the cooling wall 24 is called the "first board surface 51," and the opposite side 52 is called the "second board surface 52."

[0036] The power control method of the inverter 13 preferably employs the PWM method. The multiple switching elements 40 are configured as so-called molded power semiconductor elements, in which semiconductor chips are housed in a resin package. These switching elements 40 (power semiconductor elements 40) are provided in each phase of the three-phase inverter circuit and in this embodiment include IGBTs (Insulated Gate Bipolar Transistors). The multiple switching elements 40 are located between the printed circuit board 50 and the cooling wall 24.

[0037] Each switching element 40 comprises a switching body 41 in which a semiconductor chip is housed in a resin package, and a plurality (for example, three) of leads 42 extending from the switching body 41 to the outside. Each switching body 41 is located between the printed circuit board 50 and the cooling wall 24. The switching body 41 has a rectangular, flattened structure and has a first body surface 41a facing the printed circuit board 50 and a second body surface 41b facing the element mounting surface 24a. Of the switching body 41, the surface 41c that intersects the first body surface 41a and the second body surface 41b is called the "side surface 41c".

[0038] Referring also to Figure 4, these switching elements 40 are arranged in two rows, for example, with three elements in one row on the element mounting surface 24a of the cooling wall 24. The leads 42 of the switching elements 40 in the first row Q1 and the leads 42 of the switching elements 40 in the second row Q2 face each other.

[0039] The switching element 40 generates a large amount of heat because a large current flows through it. It is preferable to improve the heat dissipation of the heat generated by the switching element 40 to the outside. To address this, the second main body surface 41b of the switching element 40 is superimposed on the element mounting surface 24a of the cooling wall 24. It is preferable to improve thermal conductivity by ensuring close contact between the second main body surface 41b and the element mounting surface 24a. It is also preferable to improve the electrical insulation between the switching element 40 and the cooling wall 24. For this reason, it is preferable to interpose a thermally conductive gap filler 43 and an insulating sheet 44 between the second main body surface 41b and the element mounting surface 24a, as shown in Figure 3.

[0040] As shown in Figure 3, each lead 42 extends from the side surface 41c of the switching body 41 in a direction along the first substrate surface 51 of the printed circuit board 50, and then bends toward the printed circuit board 50, forming a so-called L-shape. The tip 42a of each lead 42 is inserted through a plurality of lead connection holes 53 (see also Figure 6) formed in the printed circuit board 50. The side surface 41c of the switching body 41 is where the base end 42b of the lead 42 is located, and is therefore sometimes referred to as the "side surface 41c on the lead base end side".

[0041] The inverter 13 configured as described above is integrated into a single inverter unit 60 as shown in FIG. 2, attached to the element installation surface 24a of the cooling wall 24, and then the tip portions 42a of the leads 42 protruding from the respective lead connection holes 53 are soldered to the printed circuit board 50. This inverter unit 60 may be simply referred to as unit 60. This unit 60 is composed of the inverter 13 and a frame 70 for attaching this inverter 13 to the cooling wall 24. This frame 70 is located between the printed circuit board 50 and the cooling wall 24 and is attached to the printed circuit board 50. This frame 70 is composed of a first frame 80 that biases the plurality of switching elements 40 toward the cooling wall 24 and a second frame 90 that holds the plurality of switching elements 40.

[0042] The first frame 80 is positioned close to or in contact with the first substrate surface 51 of the printed circuit board 50, and thus is located between the printed circuit board 50 and the plurality of switching elements 40. This first frame 80 is a resin molded product integrally provided with a flat first substrate 81, a first edge portion 82 and a second edge portion 83 provided on the periphery of this first substrate 81.

[0043] As shown in FIGS. 5 to 7, the first substrate 81 is formed in a substantially rectangular shape when viewed from the printed circuit board 50 side. The first edge portion 82 extends from the periphery of the first substrate 81 over the entire circumference toward the first substrate surface 51 of the printed circuit board 50. The second edge portion 83 extends from the periphery of the first substrate 81 over the entire circumference toward the element installation surface 24a of the cooling wall 24.

[0044] Referring also to FIG. 2, the first frame 80 further integrally includes a plurality of bosses 84 extending from the first substrate 81 toward the first substrate surface 51 of the printed circuit board 50, a plurality of heat sink shaft portions 85 extending from the tip end surfaces 84a of these bosses 84 (the surfaces 84a of the bosses 84 facing the printed circuit board 50) toward the first substrate surface 51, and a plurality of attachment portions 86 extending outward along the plate surface of the first substrate 81 from the first edge portion 82.

[0045] Each mounting portion 86 has a first mounting surface 86a facing the first substrate surface 51 of the printed circuit board 50, a second mounting surface 86b facing the element mounting surface 24a of the cooling wall 24, and a through hole 86c that penetrates from the first mounting surface 86a to the second mounting surface 86b. The first frame 80 can be attached to the printed circuit board 50 by overlapping the tip surface 84a of the boss 84 and the first mounting surface 86a of the mounting portion 86 with the first substrate surface 51 of the printed circuit board 50 and connecting a plurality of heat crimping shaft portions 85 to the printed circuit board 50. For example, the heat crimping shaft portion 85 is inserted through an insertion hole 54 formed in the printed circuit board 50 and heat crimped.

[0046] The cooling wall 24 has a plurality of mounting portions 24b that are erected toward the first frame 80. The second mounting surface 86b of the mounting portion 86 is superimposed on the mounting portions 24b. The printed circuit board 50 and the first frame 80 are fastened to the cooling wall 24 by fastening fastening members 87, such as screws, which are inserted through through holes 55 formed in the printed circuit board 50 and through holes 86c in the mounting portion 86, to the mounting portions 24b.

[0047] As shown in Figures 2 and 4, the second frame 90 is fitted onto the inner circumferential surface 83a of the second edge portion 83 of the first frame 80. The second frame 90 is positioned closer to the cooling wall 24 side relative to the first substrate 81 of the first frame 80, and is therefore located between the first frame 80 and the cooling wall 24. More specifically, the second frame 90 is a resin molded product integrally comprising a flat plate-shaped second substrate 91 formed in a substantially rectangular shape when viewed from the printed circuit board 50 side, and an edge portion 92 extending from the periphery of the second substrate 91 toward the element mounting surface 24a of the cooling wall 24.

[0048] As shown in FIGS. 3 and 7, the second frame 90 is attached to the first frame 80. For example, the second frame 90 is detachably attached to the first frame 80 by a plurality of latching mechanisms 100. These latching mechanisms 100 are composed of a plurality of elastic pieces 101 having elasticity and a plurality of latching recesses 102. The plurality of elastic pieces 101 extend from the edge 92 of the second frame 90 along the outer peripheral surface 83b of the second edge 83 of the first frame 80 and have latching claws 101a at their tips. The plurality of latching recesses 102 are formed on the outer peripheral surface 83b of the second edge 83 of the first frame 80. By latching the latching claws 101a to the edge 102a of the latching recesses 102, the second frame 90 does not come off from the first frame 80 toward the cooling wall 24 side.

[0049] As shown in FIGS. 3 to 5, further, the second frame 90 holds a plurality of switching elements 40 such that the positions of the tip portions 42a of the plurality of leads 42 correspond to the positions of the plurality of lead connection holes 53 provided in the printed circuit board 50. More specifically, the second frame 90 has a plurality of frame portions 110 and a plurality of lead insertion holes 120.

[0050] The plurality of frame portions 110 surround these switching elements 40 so as to individually hold the plurality of switching elements 40. The number of these frame portions 110 corresponds to the number of the plurality of switching elements 40. For example, the plurality of frame portions 110 are arranged in two rows with three in one row with respect to the second frame 90 and are partitioned by partition plates 111 from each other. The end face 112 (open end face 112) on the element installation surface 24a side of each frame portion 110 is open. Each frame portion 110 is composed of a second substrate 91, an edge 92, and a partition plate 111. A space 113 (holding space 113) surrounded by the second substrate 91, the edge 92, and the partition plate 111 is formed in each frame portion 110. Each switching element 40 is individually arranged in each holding space 113.

[0051] The side 91a of the second substrate 91 facing the holding space 113 is referred to as the "inner surface 91a of the second substrate 91". A first support projection 114 and a second support projection 115 are formed on this inner surface 91a, bulging toward the holding space 113. The first support projection 114 and the second support projection 115 support the first main surface 41a of the switching body 41 (the surface 41a facing the printed circuit board 50). The second main surface 41b of the switching body 41 protrudes toward the element mounting surface 24a than the open end surface 112 of the frame portion 110.

[0052] The multiple lead insertion holes 120 are through holes provided in the second substrate 91 of the second frame 90 at positions corresponding to the multiple lead connection holes 53, through which the multiple leads 42 are inserted. By inserting the multiple leads 42 into the multiple lead insertion holes 120, the multiple switching elements 40 are positioned on the second frame 90.

[0053] Furthermore, each of the multiple frame sections 110 has an empty space 130 on the lead insertion hole 120 side, with each switching body 41 individually housed within it. This empty space 130 is sometimes referred to as the "potting material filling section 130". The side surface 41c on the lead base end side of each switching body 41 faces the potting material filling section 130. This potting material filling section 130 is partitioned by the side surface 41c on the lead base end side of the switching body 41, the second substrate 91, and the frame section 110. In other words, the multiple potting material filling sections 130 are partitioned by the multiple switching bodies 41 and the second frame 90.

[0054] Multiple lead insertion holes 120 are connected to these potting material filling sections 130. Multiple leads 42 are located in the potting material filling section 130, extending from the side surface 41c on the lead base end side of the switching body 41 to each lead insertion hole 120. As is clear from the above description, the second frame 90 is positioned in a location corresponding to the multiple lead connection holes 53 and has multiple lead insertion holes 120 in the potting material filling section 130 through which the multiple leads 42 are inserted.

[0055] Multiple potting material filling sections 130 are filled with potting material 131 (see Figures 2 and 3). The potting material 131 has electrical insulating properties and flexibility. Multiple leads 42 are attached (held) to the second frame 90 by the flexible potting material 131. Therefore, each lead 42 is allowed to be slightly displaced relative to the second frame 90. Multiple switching elements 40 are held to the frame 70 by the attachment of multiple leads 42 to the frame 70 by the electrically insulating and flexible potting material 131.

[0056] As shown in Figures 2, 4, and 5, the frame 70 has a plurality of biasing parts 140 provided on the first frame 80 and a plurality of openings 144 provided on the second frame 90 to allow the biasing operation of these biasing parts 140.

[0057] Multiple biasing portions 140 contact the multiple switching elements 40 and bias the multiple switching elements 40 toward the cooling wall 24. The arrangement of each biasing portion 140 corresponds to the arrangement of the multiple switching elements 40. Since each biasing portion 140 is made up of a part of the first frame 80 (first substrate 81), a separate biasing member is not required. More specifically, each biasing portion 140 comprises multiple cantilevered or double-sided elastic pieces 141 formed on a flat first substrate 81, and multiple pressing protrusions 142 that project from these elastic pieces 141 toward each switching body 41. The elastic pieces 141 are sometimes referred to as "biasing pieces 141". The multiple biasing pieces 141 extend in the direction (arrow Ra) from the switching elements 40 of the first row Q1 toward the switching elements 40 of the second row Q2.

[0058] As shown in Figure 7, slits 143, 143 are provided on both sides of the multiple biasing pieces 141 of the first substrate 81. This allows the multiple biasing pieces 141 to be elastically deformed in the front-to-back direction of the first substrate 81. The multiple pressing protrusions 142 directly contact the first body surface 41a of the corresponding multiple switching bodies 41. In this example, as shown in Figure 3, a thermally conductive gap filler 43 and an insulating sheet 44 are provided between the multiple switching bodies 41 and the element mounting surface 24a of the cooling wall 24.

[0059] As shown in Figures 2 and 5, the multiple openings 144 are formed in the multiple frame portions 110 of the second frame 90. More specifically, the multiple openings 144 are through holes that penetrate the second substrate 91, which forms part of each frame portion 110. The multiple pressing protrusions 142 of the multiple biasing portions 140 can pass through the multiple openings 144 and come into contact with the multiple switching elements 40.

[0060] In Figure 2, the biasing portion 140 and switching element 40 shown on the right represent a state in which the switching body 41 of the switching element 40 has been virtually removed, and the biasing piece 141 of the biasing portion 140 is flat and not elastically deformed. On the other hand, the biasing portion 140 and switching element 40 shown on the left represent a state in which the pressing projection 142 is in contact with the switching element 40, and the elastic piece 141 is elastically deformed, biasing the switching element 40 against the cooling wall 24.

[0061] As shown in Figures 3 and 8, the first frame 80 further has a plurality of lead correction holes 151 for correcting the position of each lead 42 of a plurality of switching elements 40 held by the second frame 90, and a plurality of recesses 152 (tapered recesses 152) that communicate individually with these lead correction holes 151. The plurality of lead correction holes 151 and the plurality of recesses 152 are formed inside a flat first substrate 81 and a plurality of bulging portions 153 (cylindrical portions 153) that bulge out from the first substrate 81 toward the printed circuit board 50. The plurality of lead correction holes 151 and the plurality of recesses 152 are located on the first substrate 81 corresponding to a plurality of lead connection holes 53. These lead correction holes 151 are located on the tip side of each bulging portion 153. The plurality of recesses 152 are located on the base end side of each bulging portion 153 and communicate with each lead correction hole 151.

[0062] Multiple leads 42 are inserted into multiple recesses 152 from the second substrate 91 side of the second frame 90, and further into multiple lead straightening holes 151. By inserting the multiple leads 42 into the multiple lead straightening holes 151, the positions of the multiple leads 42 are straightened to align with the multiple lead connection holes 53.

[0063] The multiple inner wall surfaces 152a that form the multiple recesses 152 are tapered from the side of the multiple switching elements 40 toward the multiple lead straightening holes 151. When the second frame 90 is assembled to the first frame 80, the tapered inner wall surfaces 152a guide each lead 42 of each switching element 40 held in the second frame 90 toward the multiple lead straightening holes 151.

[0064] As shown in Figure 8, the spatial distance between adjacent leads 42, 42 is L1. Now, let's consider adjacent lead straightening holes 151. Let P1 be the boundary (first boundary point) between the inner wall surface 151a forming one lead straightening hole 151 and the inner wall surface 152a forming the recess 152. Let P2 be the boundary (second boundary point) between the inner wall surface 151a forming the other lead straightening hole 151 and the inner wall surface 152a forming the recess 152. The distance L2 from the first boundary point P1 to the second boundary point P2 along the two inner wall surfaces 151a, 152a and the second substrate 91 is called the "creepage distance L2 between leads 42, 42". The creepage distance L2 is longer than the spatial distance L1. In this way, the inner wall surfaces 152a, 152a of the adjacent recesses 152, 152 increase the creepage distance L2 between adjacent leads 42, 42 compared to the spatial distance L1 between adjacent leads 42, 42, thereby improving the electrical insulation between adjacent leads 42, 42.

[0065] Next, an example of how to assemble the inverter unit 60 will be described with reference to Figures 3 and 6.

[0066] (First frame sub-assembly process) First, the first frame 80 is superimposed on the printed circuit board 50 so that the heat-sealing shaft portion 85 of the first frame 80 is inserted into the insertion hole 54 formed in the printed circuit board 50. As a result, the tip surface 84a of the boss 84 of the first frame 80 is superimposed on the first substrate surface 51 of the printed circuit board 50, while corresponding to the insertion hole 54 of the printed circuit board 50. Furthermore, the first frame 80 is temporarily assembled to the printed circuit board 50 by heat-sealing the heat-sealing shaft portion 85 inserted into the insertion hole 54. As a result, the first frame sub-assembly 161 (see Figure 3) is formed by the printed circuit board 50 and the first frame 80.

[0067] (Second frame subassembly process) Next, the leads 42 of the multiple switching elements 40 are inserted through the lead insertion holes 120 of the second frame 90, and the switching body 41 is placed in the holding space 113 of the second frame 90 and held in the frame portion 110. Furthermore, the potting material 131 is filled into the potting material filling portion 130 and hardened to form the second frame subassembly 162 (see Figure 3).

[0068] (Printed circuit board assembly process) Next, the leads 42 of each switching element 40 protruding from the second frame subassembly 162 are inserted into the lead straightening holes 151 of the first frame 80 of the first frame subassembly 161 and the lead connection holes 53 of the printed circuit board 50. Also, the retaining claws 101a of the elastic piece 101 extending from the second frame 90 are retained in the retaining recesses 102 of the first frame 80. As a result, a printed circuit board assembly 163 (inverter unit 60) is formed in which the printed circuit board 50, the first frame 80, the second frame 90, and the switching elements 40 are temporarily assembled. At this time, the pressing protrusions 142 of the first frame 80 are in contact with the switching elements 40, but because the deformation of the biasing piece 141 is small, the biasing force that the switching elements 40 receive from the biasing piece 140 is also small.

[0069] (Preparation process for mounting printed circuit board assembly) Next, an insulating sheet 44 is placed on the element mounting surface 24a of the cooling wall 24. Furthermore, a thermal conductive gap filler 43 is applied to the portion of the insulating sheet 44 that comes into contact with the switching element 40.

[0070] (Printed Circuit Board Assembly Mounting Process) Next, the printed circuit board assembly 163 is placed so that the mounting portion 86 of the first frame 80, which is superimposed on the printed circuit board 50, corresponds to the mounting portion 24b erected on the cooling wall 24. At this time, the switching element 40 is in contact with the insulating sheet 44 and the thermally conductive gap filler 43 installed on the element mounting surface 24a, but the second mounting surface 86b of the mounting portion 86 of the first frame 80 and the mounting portion 24b are slightly separated by the biasing force of the biasing portion 140. Next, the fastening member 87 is inserted through the through hole 55 of the printed circuit board 50 and the through hole 86c of the mounting portion 86 of the first frame 80 and fastened to the mounting portion 24b. By tightening the fastening member 87, the entire printed circuit board assembly 163 is pushed against the biasing force of the biasing portion 140 until the second mounting surface 86b of the mounting portion 86 contacts the mounting portion 24b. This pressing action causes the elastically deformed biasing portion 140 to press the switching element 40 against the cooling wall 24 with appropriate biasing force. This completes the assembly of the inverter unit 60.

[0071] The assembly method for the inverter unit 60 is not limited to the procedure described above. For example, it is possible to first combine the first frame 80 and the second frame 90 without constructing the first frame subassembly 161 in the first frame subassembly step, and then assemble the printed circuit board 50.

[0072] To summarize the electric compressor 10 described above, it is as follows:

[0073] Refer to Figures 1 and 2. The electric compressor 10 includes a compression mechanism 11 for compressing a refrigerant, an electric motor 12 for driving the compression mechanism 11, an inverter 13 for controlling the electric motor 12, a motor housing chamber 22a in which the electric motor 12 is housed, an inverter housing chamber 23a in which the inverter 13 is housed, and a cooling wall 24 that separates the motor housing chamber 22a and the inverter housing chamber 23a and is cooled by the refrigerant flowing through the motor housing chamber 22a. The inverter 13 includes a plurality of switching elements 40 for controlling the driving of the electric motor 12, and a printed circuit board 50 on which these plurality of switching elements 40 can be mounted. The plurality of switching elements 40 are located between the printed circuit board 50 and the cooling wall 24.

[0074] Furthermore, the electric compressor 10 is located between the printed circuit board 50 and the plurality of switching elements 40, and includes a first frame 80 that biases the plurality of switching elements 40 to the cooling wall 24, and a second frame 90 that is attached to the first frame 80 and holds the plurality of switching elements 40.

[0075] In this configuration, multiple switching elements 40 are held by a single second frame 90, this second frame 90 is attached to a single first frame 80, and this first frame 80 biases the switching elements 40 against the cooling wall 24. Therefore, the holding function of holding the multiple switching elements 40 and the biasing function of biasing the multiple switching elements 40 can be stably separated. Moreover, the configuration for holding multiple switching elements 40 and biasing them against the cooling wall 24 can be compactly unitized (integrated) with a small number of parts, simply by combining a single first frame 80 and a single second frame 90. In addition, since the configuration for holding multiple switching elements 40 and biasing them against the cooling wall 24 only requires attaching the second frame 90 to the first frame 80, it is advantageous in terms of the ease of assembly and disassembly of the multiple switching elements 40 to the cooling wall 24.

[0076] Refer to Figures 2 and 3. The printed circuit board 50 has multiple lead connection holes 53 to which multiple leads 42 of multiple switching elements 40 are connected. The second frame 90 holds the multiple switching elements 40 such that the positions of the multiple leads 42 correspond to the positions of the multiple lead connection holes 53.

[0077] In this way, by positioning and holding multiple switching elements 40 on the second frame 90, the positions of the multiple leads 42 can be easily and reliably associated with the positions of the multiple lead connection holes 53.

[0078] Refer to Figure 3. The second frame 90 has multiple lead insertion holes 120 through which multiple leads 42 are inserted, at positions corresponding to the multiple lead connection holes 53. By inserting the multiple leads 42 through the multiple lead insertion holes 120, the multiple switching elements 40 are positioned on the second frame 90.

[0079] Therefore, by simply inserting multiple leads 42 into multiple lead insertion holes 120 of the second frame 90, the positioning of multiple switching elements 40 relative to the second frame 90 can be easily and reliably performed.

[0080] Refer to Figure 2. The first frame 80 has a plurality of lead straightening holes 151 through which a plurality of leads 42 are inserted, at positions corresponding to a plurality of lead connection holes 53. By inserting the plurality of leads 42 through the plurality of lead straightening holes 151, the positions of the plurality of leads 42 are straightened to match the plurality of lead connection holes 53.

[0081] Therefore, the second frame 90 aligns the positions of the leads 42 of the multiple switching elements 40, and the multiple lead correction holes 151 of the first frame 80 correct any deformation such as tilting of each lead 42, allowing them to be easily guided into the multiple lead connection holes 53.

[0082] Refer to Figure 2. The first frame 80 is attached to the printed circuit board 50. Since the first frame 80 is attached to the printed circuit board 50 and not to the inverter housing 23, the assembly and removal of the multiple switching elements 40 to and from the inverter housing 23 becomes easier.

[0083] Refer to Figures 2 and 6. The electric compressor 10 further has a mounting portion 24b that is erected from the cooling wall 24 toward the first frame 80. The first frame 80 has a mounting portion 86 that is sandwiched between the printed circuit board 50 and the mounting portion 24b. The printed circuit board 50 and the mounting portion 86 are fastened to the mounting portion 24b by a common fastening member 87.

[0084] The mounting portion 86 of the first frame 80 is sandwiched between the mounting portion 24b and the printed circuit board 50, and is attached to the mounting portion 24b by a fastening member 87 common to the printed circuit board 50. By fastening the fastening member 87 to the mounting portion 24b, the first frame 80 is pressed against the cooling wall 24. As a result, the multiple switching elements 40 held by the second frame 90 are biased by the first frame 80 and pressed against the cooling wall 24. Therefore, by simply attaching the printed circuit board 50 and the first frame 80 to the mounting portion 24b using a common fastening member 87, the printed circuit board 50 and the first frame 80 can be easily attached, and the multiple switching elements 40 can be pressed against the cooling wall 24 and brought into close contact. Moreover, by simply removing the common fastening member 87 from the cooling wall 24, the unit 60 consisting of the first frame 80, the second frame 90 and the multiple switching elements 40 can be easily removed from the cooling wall 24.

[0085] Refer to Figures 2 and 6. The first frame 80 has a plurality of biasing portions 140 that contact a plurality of switching elements 40 and bias the cooling wall 24. The plurality of biasing portions 140 are made up of a part of the first frame 80 (first substrate 81).

[0086] The biasing section 140 that biases the switching element 40 to the cooling wall 24 is formed from a part of the first frame 80. There is no need to arrange a separate biasing member for biasing the switching element 40. The number of parts can be reduced in the inverter 13 of an electric compressor 10 that uses multiple switching elements 40.

[0087] Refer to Figures 2 and 5. The second frame 90 is located between the first frame 80 and the cooling wall 24 and has a frame portion 110 that surrounds the plurality of switching elements 40. The frame portion 110 has openings 144 through which the plurality of biasing portions 140 of the first frame 80 can be inserted and contact the plurality of switching elements 40.

[0088] Multiple biasing parts 140 on the first frame 80 can be inserted through openings 144 in the frame portion 110 of the second frame 90, thereby biasing the multiple switching elements 40 toward the cooling wall 24. Despite the frame portion 110 of the second frame 90 being interposed between the multiple biasing parts 140 and the multiple switching elements 40, the multiple biasing parts 140 can easily and reliably bias the multiple switching elements 40 toward the cooling wall 24.

[0089] Refer to Figures 2 and 3. The multiple leads 42 extend from the side surfaces 41c of each switching body 41 of the multiple switching elements 40 and are bent toward the multiple lead insertion holes 120 of the second frame 90, having an L-shaped configuration and are held to the second frame 90 by an electrically insulating and flexible potting material 131.

[0090] Each lead 42 of the multiple switching elements 40 is held to the second frame 90 by a flexible potting material 131, allowing for slight movement in the insertion and removal directions relative to the lead connection holes 53 of the printed circuit board 50. This increases the durability of the connection portion of each lead 42 to the printed circuit board 50.

[0091] Refer to Figure 8. The first frame 80 has a plurality of recesses 152 into which a plurality of leads 42 are individually inserted. The plurality of recesses 152 communicate with a plurality of lead straightening holes 151. The plurality of inner wall surfaces 152a that form the plurality of recesses 152 increase the creepage distance L2 between adjacent leads 42 (between two adjacent leads 42, 42 of the plurality of leads 42) relative to the spatial distance L1 between adjacent leads 42 (between two adjacent leads 42, 42 of the plurality of leads 42).

[0092] The electrical insulation between each lead 42 can be improved by a simple configuration that increases the creepage distance L2 between adjacent leads 42, through multiple inner wall surfaces 152a that form multiple recesses 152 into which multiple leads 42 are individually inserted.

[0093] Refer to Figure 8. The inner wall surface 152a that forms the recess 152 (tapered recess 152) is formed in a tapered shape that narrows from the switching element 40 side toward the lead straightening hole 151. The lead 42 of the switching element 40 can be smoothly guided toward the lead straightening hole 151 by the tapered inner wall surface 152a.

[0094] Furthermore, the present invention is not limited to the embodiments, provided that it achieves the function and effects of the present invention. For example, the cooling wall 24 only needs to be capable of cooling the switching element 40 and may be located on either the motor housing 22 or the inverter housing 23. The switching element 40 is not limited to a configuration including an IGBT, but may be other switching elements such as a MOSFET, or an IPM (Intelligent Power Module) including a switching element. In addition, instead of providing a thermally conductive gap filler 43 and an insulating sheet 44 between the switching element 40 and the element mounting surface 24a, only a thermal paste having both thermal conductivity and electrical insulation properties may be provided.

[0095] The electric compressor 10 of the present invention is suitable for use in a refrigeration cycle.

[0096] 10...Electric compressor, 11...Compression mechanism, 12...Electric motor, 13...Inverter, 22...Motor housing, 22a...Motor housing chamber, 23...Inverter housing, 23a...Inverter housing chamber, 24...Cooling wall (partition wall 24), 24a...Element mounting surface, 24b...Mounting part, 40...Switching element, 41...Switching body, 41c...Side view, 42...Lead, 42a...Tip of lead 42, 50...Printed circuit board, 53...Lead connection hole, 60...Unit (inverter unit), 80...First frame, 81...First circuit board, 86...Mounting part, 87...Fastening member, 90...Securing mechanism, 110...Frame part, 120...Lead insertion hole, 130...Potting material filling part, 131...Potting material, 140... biasing portion, 144... opening, 151... lead straightening hole, 152... recess (tapered recess), 152a... inner wall surface forming the recess, 153... cylindrical portion (bulging portion), L1... space distance, L2... creepage distance.

Claims

1. An electric compressor (10) comprising: a compression mechanism (11) for compressing a refrigerant; an electric motor (12) for driving the compression mechanism (11); an inverter (13) for controlling the electric motor (12); a motor housing chamber (22a) for housing the electric motor (12); an inverter housing chamber (23a) for housing the inverter (13); and a cooling wall (24) that partitions the motor housing chamber (22a) and the inverter housing chamber (23a) and is cooled by the refrigerant flowing through the motor housing chamber (22a); wherein the inverter (13) comprises a plurality of switching elements (40) for controlling the driving of the electric motor (12); and a printed circuit board (50) on which the plurality of switching elements (40) can be mounted; wherein the plurality of switching elements (40) are located between the printed circuit board (50) and the cooling wall (24), An electric compressor comprising: a first frame (80) positioned between the printed circuit board (50) and the plurality of switching elements (40) and biasing the plurality of switching elements (40) toward the cooling wall (24); and a second frame (90) attached to the first frame (80) and holding the plurality of switching elements (40).

2. The electric compressor according to claim 1, wherein the printed circuit board (50) has a plurality of lead connection holes (53) to which the plurality of leads (42) of the plurality of switching elements (40) are connected, and the second frame (90) holds the plurality of switching elements (40) such that the positions of the plurality of leads (42) correspond to the positions of the plurality of lead connection holes (53).

3. The electric compressor according to claim 2, wherein the second frame (90) has a plurality of lead insertion holes (120) through which the plurality of leads (42) are inserted at positions corresponding to the plurality of lead connection holes (53), and the plurality of switching elements (40) are positioned on the second frame (90) by inserting the plurality of leads (42) through the plurality of lead insertion holes (120).

4. The electric compressor according to claim 2, wherein the first frame (80) has a plurality of lead straightening holes (151) through which the plurality of leads (42) are inserted at positions corresponding to the plurality of lead connection holes (53), and the positions of the plurality of leads (42) are straightened to match the plurality of lead connection holes (53) by inserting the plurality of leads (42) into the plurality of lead straightening holes (151).

5. The electric compressor according to claim 1, wherein the first frame (80) is attached to the printed circuit board (50).

6. The electric compressor according to claim 1, further comprising a mounting portion (24b) erected from the cooling wall (24) toward the first frame (80), wherein the first frame (80) has a mounting portion (86) sandwiched between the printed circuit board (50) and the mounting portion (24b), and the printed circuit board (50) and the mounting portion (86) are fastened to the mounting portion (24b) by a common fastening member (87).

7. The electric compressor according to claim 1, wherein the first frame (80) has a plurality of biasing portions (140) that contact the plurality of switching elements (40) and bias the cooling wall (24), and the plurality of biasing portions (140) are formed by a part of the first frame (80).

8. The electric compressor according to claim 7, wherein the second frame (90) is located between the first frame (80) and the cooling wall (24), and has a frame portion (110) surrounding the plurality of switching elements (40), and the frame portion (110) has an opening (144) through which the plurality of biasing portions (140) of the first frame (80) can be inserted and contact the plurality of switching elements (40).

9. The electric compressor according to claim 3, wherein the plurality of leads (42) extend from the side surface (41c) of each switching body (41) of the plurality of switching elements (40) and are bent toward the plurality of lead insertion holes (120) of the second frame (90), and are held in place by an electrically insulating and flexible potting material (131).

10. The electric compressor according to claim 4, wherein the first frame (80) has a plurality of recesses (152) into which the plurality of leads (42) are individually inserted, the plurality of recesses (152) communicate with the plurality of lead straightening holes (151), and the plurality of inner wall surfaces (152a) forming the plurality of recesses (152) increase the creepage distance (L2) between adjacent leads (42) with respect to the spatial distance (L1) between adjacent leads (42).

11. The electric compressor according to claim 10, wherein the inner wall surface (152a) forming the recess (152) is formed in a tapered shape that narrows from the switching element (40) side toward the lead straightening hole (151).

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