Electric compressor

Abstract

Provided is an electric compressor (10) comprising an inverter (13) that controls an electric motor (12). The inverter (13) comprises a plurality of switching elements (40) mounted on a printed circuit board (50). The plurality of switching elements (40) comprise: a plurality of switching bodies (41) located between the printed circuit board (50) and a cooling wall (24); and a plurality of leads (42) extending from the plurality of switching bodies (41) and connected to the printed circuit board (50). The plurality of switching elements (40) are held by a frame (70) by the plurality of leads (42) being attached to the frame (70) with a flexible potting material (131).

Description

Electric compressor

[0001] The present invention relates to an improved technology of an electric compressor including a compression mechanism for compressing a refrigerant, 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 driving 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 that the heat generated by the switching element is cooled by 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 technology of Patent Document 1 is known.

[0005] The electric compressor known from Patent Document 1 provides a guide member between the printed circuit board and the switching element, and biases the switching element toward the housing side by a spring member disposed between the guide member and the switching element. The lead of the switching element is connected to the printed circuit board.

[0006] Japanese Patent Application Laid-Open No. 2013-026320

[0007] In the electric compressor known from Patent Document 1, the guide member is fastened to the housing (cooling member) with screws, and then the leads of the switching element are soldered to the printed circuit board. Depending on the mounting structure of the printed circuit board itself, excessive pulling or pushing forces of the leads may be applied to the connection part between the printed circuit board and the leads relative to the lead connection holes.

[0008] The present invention has been made to solve the above-mentioned problems, and aims to provide a structure that can improve the durability of the connection portion of the leads of each switching element to the printed circuit board in an inverter of an electric compressor that uses multiple switching elements.

[0009] 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.

[0010] According to the present invention, the invention 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. The electric compressor (10) comprises a plurality of switching elements (40) including a plurality of switching bodies (41) located between the printed circuit board (50) and the cooling wall (24), and a plurality of leads (42) extending from the plurality of switching bodies (41) to the printed circuit board (50) and connected thereto, wherein the electric compressor (10) comprises a frame (70) located between the printed circuit board (50) and the cooling wall (24) and attached to the printed circuit board (50), and the plurality of switching elements (40) are held in the frame (70) by the plurality of leads (42) being attached to the frame (70) by a potting material (131) having electrical insulating and flexible properties.

[0011] Preferably, the frame (70) comprises a first frame (80) located between the printed circuit board (50) and the plurality of switching elements (40) and attached to the printed circuit board (50), and a second frame (90) located between the first frame (80) and the cooling wall (24) and attached to the first frame (80), wherein the plurality of leads (42) are attached to the second frame (90) within the frame (70) by the potting material (131), and the first frame (80) biases the plurality of switching bodies (41) toward the cooling wall (24).

[0012] More preferably, the system further includes a potting material filling section (130) for filling with the potting material (131), the potting material filling section (130) being partitioned by the plurality of switching bodies (41) and the second frame (90), and the plurality of leads (42) being held by the second frame (90) via the potting material (131) filled in the potting material filling section (130).

[0013] More preferably, the printed circuit board (50) has a plurality of lead connection holes (53) through which the plurality of leads (42) of the plurality of switching elements (40) are connected, and the plurality of leads (42) have an L-shaped configuration extending from the side surface (41c) of each of the plurality of switching bodies (41) of the plurality of switching elements (40) and bending toward the plurality of lead connection holes (53), and the second frame (90) has a plurality of lead insertion holes (95) in the potting material filling portion (130) at positions corresponding to the plurality of lead connection holes (53), through which the plurality of leads (42) are inserted, and the plurality of leads (42) are inserted through the plurality of lead insertion holes (95) and supported by the potting material (131).

[0014] 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).

[0015] In another preferred example, the cooling wall (24) further has a mounting portion (24b) erected toward the first frame (80), and a single unit (60) is formed by the printed circuit board (50), the first frame (80) attached to the printed circuit board (50), the second frame (90) attached to the first frame (80), and the plurality of switching elements (40) whose plurality of leads (42) are held by the second frame (90), and the single unit (60) is fastened to the mounting portion (24b) by a fastening member (87).

[0016] In yet another preferred example, the first frame (80) has a plurality of biasing portions (140) that abut against the plurality of switching bodies (41) and bias the cooling wall (24), wherein the plurality of biasing portions (140) are formed from a part of the first frame (80) and abut against the plurality of switching bodies (41) directly without overlapping with the first frame (80) in the biasing direction (Rc).

[0017] In another preferred example, 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) communicating 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).

[0018] 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).

[0019] More preferably, the first frame (80) includes a positioning unit (121) that positions each of the plurality of switching bodies (41) in the direction (Rb) in which the plurality of switching elements 40 are aligned.

[0020] In the present invention, the durability of the connection portion of each lead to the printed circuit board can be improved in an inverter for an electric compressor that uses multiple switching elements.

[0021] This is a cross-sectional view of an electric compressor according to an 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 switching element and frame shown in Figure 2, viewed from the cooling wall side. This is an exploded view of the switching element and frame shown in Figure 4. Figure 6A is an exploded view of the inverter unit and cooling wall shown in Figure 2, viewed from the printed circuit board side, and Figure 6B is a side view of the fastening portion of the printed circuit board and frame shown in Figure 6A. Figure 7A is a diagram showing the relationship between the second frame and the switching element shown in Figure 4, and Figure 7B is a partially enlarged perspective view of the relationship between the second frame and the switching element shown in Figure 7A. This is a perspective view of the switching element and frame shown in Figure 4, viewed from the printed circuit board side. This is a cross-sectional view showing the relationship between multiple leads and each hole of one switching element shown in Figure 3.

[0022] 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.

[0023] <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.

[0024] 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.

[0025] 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.

[0026] 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.

[0027] 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.

[0028] 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.

[0029] 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.

[0030] 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."

[0031] 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.

[0032] 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".

[0033] Referring 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. The direction from the first row Q1 to the second row Q2 (arrow Ra) is called the "first direction Ra".

[0034] 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.

[0035] 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 into a plurality of lead connection holes 53 (see also Figure 6A) 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".

[0036] The inverter 13 configured in this way is assembled into a single inverter unit 60, as shown in Figure 2, and attached to the element mounting surface 24a of the cooling wall 24. After that, the tips 42a of each lead 42 protruding from each lead connection hole 53 are soldered to the printed circuit board 50. This inverter unit 60 is sometimes simply referred to as the unit 60. This unit 60 consists of the inverter 13 and a frame 70 that attaches the 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 consists of a first frame 80 that biases the multiple switching elements 40 to the cooling wall 24 and a second frame 90 that holds the multiple switching elements 40.

[0037] The first frame 80 is positioned between the printed circuit board 50 and the plurality of switching elements 40 by being located in close proximity to or in contact with the first substrate surface 51 of the printed circuit board 50. Referring also to Figure 5, this first frame 80 is an electrically insulating resin molded product integrally comprising a flat first substrate 81 and an edge portion 82 having a periphery of the first substrate 81. The first substrate 81 is formed in a substantially rectangular shape when viewed from the printed circuit board 50 side. The edge portion 82 extends from the periphery of the first substrate 81 all around toward the element mounting surface 24a of the cooling wall 24.

[0038] As shown in Figures 6A and 6B, the first frame 80 further integrally includes a plurality of bosses 84 extending outward from the edge 82 along the surface of the first substrate 81, a plurality of heat-sealing shafts 85 extending from the tip surfaces 84a of these bosses 84 (the surfaces 84a of the bosses 84 that face the printed circuit board 50) toward the first substrate surface 51 of the printed circuit board 50, and a plurality of mounting portions 86 extending outward from the edge 82 along the surface of the first substrate 81.

[0039] 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.

[0040] 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.

[0041] As shown in Figures 2, 4, and 5, the second frame 90 is fitted onto the inner circumferential surface 82a of the edge portion 82 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. The second frame 90 is an electrically insulating 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 a pair of first edges 92, 92 and a pair of second edges 93, 93 extending from the second substrate 91 toward the element mounting surface 24a of the cooling wall 24.

[0042] More specifically, as shown in Figures 7A and 7B, three switching elements 40 are aligned on the second frame 90 in the longitudinal direction (arrow Rb) of the rectangle of the second substrate 91. The direction in which these three switching elements 40 are aligned (arrow Rb) is called the "second direction Rb". The second direction Rb is perpendicular to the first direction Ra. The first edges 91a, 91a of the second substrate 91 are aligned along the first direction Ra. The pair of edges 91b, 91b of the second substrate 91 that are aligned along the second direction Rb are called the "second edges 91b, 91b". The second edges 91b, 91b are perpendicular to the first edges 91a, 91a. The pair of first edges 92, 92 are located on the first edges 91a, 91a of the second substrate 91. The pair of second edges 93, 93 are located on the second edges 91b, 91b of the second substrate 91.

[0043] As shown in FIGS. 5 and 8, 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 a pair of first edges 92, 92 of the second frame 90 along the outer peripheral surface 82b of the edge 82 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 82b of the edge 82 of the first frame 80. When the latching claws 101a are latched to the edge of the latching recesses 102, the second frame 90 does not come off from the first frame 80 toward the cooling wall 24 side.

[0044] As shown in FIG. 5, the second frame 90 is positioned with respect to the first frame 80 by the fitting of a plurality of positioning pins 103 provided on the first frame 80 and a plurality of positioning holes 104 provided on the second frame 90. Thereby, when the second frame 90 is latched to the first frame 80 by the latching mechanism 100, it can be accurately positioned.

[0045] As shown in FIGS. 3 and 6A, 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 on the printed circuit board 50.

[0046] As shown in FIGS. 3, 7A, and 7B, the second frame 90 holds only a part 41d on the side surface 41c side of each of the plurality of switching bodies 41. The part 41d on the side surface 41c side of the plurality of switching bodies 41 is referred to as a "held portion 41d". The portion 110 of the second frame 90 that holds the plurality of held portions 41d is referred to as a "holding portion 110".

[0047] A pair of second edge portions 93, 93 have a plurality of notch openings 111 that are cut out along the inner surface 91c of the second substrate 91 and penetrate both the inside and outside. Here, the inner surface 91c of the second substrate 91 refers to the surface 91c of the second substrate 91 that faces the element installation surface 24a of the cooling wall 24. The plurality of holding portions 110 are constituted by the surfaces 112 (opening forming surfaces 112) that form each notch opening 111. These opening forming surfaces 112 have a step 113 that is one step higher in the penetration direction of each notch opening 111 from the second edge 91b. When the side surfaces 41c of each switching body 41 abut against the respective steps 113 and the held portions 41d of each switching body 41 overlap the respective opening forming surfaces 112, the held portions 41d of each switching body 41 are positioned and held by the plurality of holding portions 110 of the second frame 90.

[0048] Furthermore, the second frame 90 has a plurality of lead insertion holes 95 at positions corresponding to the plurality of lead connection holes 53 (see FIG. 3) in the second substrate 91. Each lead insertion hole 95 is a through hole provided in the second substrate 91, and a plurality of leads 42 are inserted therethrough. By inserting the plurality of leads 42 through the plurality of lead insertion holes 95, the plurality of switching elements 40 are positioned on the second frame 90.

[0049] As described above, each switching body 41 is held by the second frame 90 only by the held portion 41d. Referring also to FIG. 4, other portions 41e, 41e of each switching body 41 except for the held portion 41d are supported by the first frame 80. For example, the other portions 41e, 41e are side surfaces 41e, 41e (other side surfaces 41e, 41e) in the direction along the first edge 91a when the switching body 41 is viewed from the element installation surface 24a side (see FIG. 2).

[0050] More specifically, as shown in Figure 4, the first frame 80 is equipped with a plurality of positioning parts 121 that position each of the plurality of switching bodies 41 in the direction Rb (second direction Rb) in which the plurality of switching elements 40 are aligned. Here, the plurality of switching bodies 41 refers to each of the plurality of switching bodies 41. Each positioning part 121 consists of vertical plate-shaped ribs provided on the inner circumferential surface 82a of the edge portion 82 and on both sides of the plurality of partition plates 122. The plurality of partition plates 122 extend from the first substrate 81 toward the element mounting surface 24a of the cooling wall 24 and partition the spaces between adjacent switching bodies 41 in the second direction Rb. The other sides 41e, 41e of each switching body 41 are positioned by each positioning part 121.

[0051] As shown in Figures 2, 7A, and 7B, each switching body 41 is individually held in the second frame 90, and each lead 42 is attached to the second frame 90 by potting material 131 (see Figure 2) filled in a plurality of potting material filling sections 130. The plurality of potting material filling sections 130 are formed by a space enclosed by the second frame 90 and the plurality of switching bodies 41 held in the second frame 90. More specifically, each potting material filling section 130 is partitioned by a second substrate 91, a pair of first edges 92, 92 and a pair of second edges 93, 93, a partition plate 132 formed on the second substrate 91 and the side surfaces 41c of the plurality of switching bodies 41, and each lead 42 is individually enclosed.

[0052] Multiple lead insertion holes 95 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 95. As is clear from the above description, the second frame 90 is located in a position corresponding to the multiple lead connection holes 53 (see Figure 2), and has multiple lead insertion holes 95 in the potting material filling section 130 through which the multiple leads 42 are inserted.

[0053] Multiple potting material filling sections 130 are filled with potting material 131 (see Figure 2). 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.

[0054] As shown in Figures 2 and 8, the first frame 80 has a plurality of biasing portions 140. The plurality of biasing portions 140 contact the plurality of switching elements 40 and bias the cooling wall 24. The arrangement of each biasing portion 140 corresponds to the arrangement of the plurality of 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 a plurality of cantilevered or double-sided elastic pieces 141 formed on the flat first substrate 81, and a plurality of pressing protrusions 142 that project from these elastic pieces 141 toward each switching body 41. The elastic pieces 141 are sometimes called "biasing pieces 141". The plurality of biasing pieces 141 extend in the first direction Ra.

[0055] As shown in Figures 2 and 8, slits 143, 143 are provided on both sides of the multiple biasing pieces 141 of the first substrate 81, respectively. 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 way, the multiple biasing parts 140 directly contact the multiple switching bodies 41 without overlapping with the first frame 80 in the biasing direction Rc. 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.

[0056] As shown in Figure 9, 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.

[0057] 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.

[0058] 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.

[0059] 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.

[0060] Next, an example of how to assemble the inverter unit 60 will be described with reference to Figures 3, 6A, and 6B.

[0061] (First frame subassembly process) First, the first frame 80 is placed on top of 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 aligned with the first substrate surface 51 (see Figure 3) 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 subassembly 161 (see Figure 3) is formed by the printed circuit board 50 and the first frame 80.

[0062] (Second frame subassembly process) Next, the leads 42 of the multiple switching elements 40 are inserted through the lead insertion holes 95 of the second frame 90, and the switching body 41 is held in the holding portion 110 of the second frame 90. 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).

[0063] (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, as shown in Figure 4, 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 amount of 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.

[0064] (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.

[0065] (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 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 thermal 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 (see Figure 3). 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 part 140 until the second mounting surface 86b of the mounting portion 86 contacts the mounting portion 24b. This pushing causes the elastically deformed biasing part 140 to press the switching element 40 against the cooling wall 24 with an appropriate biasing force. This completes the assembly of the inverter unit 60.

[0066] 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.

[0067] To summarize the electric compressor 10 described above, it is as follows:

[0068] 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 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. 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 the plurality of switching elements 40 can be mounted. The plurality of switching elements 40 include a plurality of switching bodies 41 located between the printed circuit board 50 and the cooling wall 24, and a plurality of leads 42 extending from the plurality of switching bodies 41 to the printed circuit board 50 and connected thereto.

[0069] Furthermore, the electric compressor 10 includes a frame 70 that is positioned between the printed circuit board 50 and the cooling wall 24 and is attached to the printed circuit board 50. Multiple switching elements 40 are held in place by the frame 70, with multiple leads 42 attached to the frame 70 by a potting material 131 that has electrical insulating and flexible properties.

[0070] Each lead 42 of the multiple switching elements 40 is held to the frame 70 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. For example, when pulling or pushing forces are applied to the connection portion (soldering portion) between the printed circuit board 50 and the lead 42 relative to the lead connection hole 53, the lead 42 can move slightly in the direction of these forces. This increases the durability of the connection portion (soldering portion) of each lead 42 to the printed circuit board 50.

[0071] Refer to Figure 2. The frame 70 consists of a first frame 80 located between the printed circuit board 50 and the plurality of switching elements 40 and attached to the printed circuit board 50, and a second frame 90 located between the first frame 80 and the cooling wall 24 and attached to the first frame 80. The plurality of leads 42 are attached to the second frame 90 within the frame 70 by potting material 131. The first frame 80 biases the plurality of switching bodies 41 toward the cooling wall 24.

[0072] Multiple switches 40 are held by the second frame 90 by attaching multiple leads 42 to the second frame 90 with an electrically insulating and flexible potting material 131. The first frame 80 biases multiple switching bodies 41 toward the cooling wall 24. Multiple switches 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 switches 40 toward the cooling wall 24. Therefore, the holding function of holding multiple switches 40 and the biasing function of biasing multiple switches 40 can be stably separated. Moreover, the configuration that holds multiple switches 40 and biases them toward the cooling wall 24 can be compactly unitized (integrated) with a small number of parts by simply 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 is simply to attach the second frame 90 to the first frame 80, it is advantageous in terms of the ease of assembling and disassembling the multiple switching elements 40 to the cooling wall 24.

[0073] Refer to Figure 2. The electric compressor 10 has a potting material filling section 130 for filling with potting material 131. This potting material filling section 130 is partitioned by a plurality of switching bodies 41 and a second frame 90. A plurality of leads 42 are held by the second frame 90 via the potting material 131 filled in the potting material filling section 130.

[0074] Each lead 42 of the multiple switching elements 40 is attached to the second frame 90 by potting material 131 filled in the potting material filling section 130. The potting material filling section 130 is partitioned by each switching body 41 of the multiple switching elements 40 and the second frame 90. Since each switching body 41 itself is effectively utilized to partition a part of the potting material filling section 130, the configuration of the potting material filling section 130 can be simplified and miniaturized.

[0075] Refer to Figure 2. The printed circuit board 50 has a plurality of lead connection holes 53 to which a plurality of leads 42 of a plurality of switching elements 40 are connected. The plurality of leads 42 extend from the side surface 41c of each of the plurality of switching bodies 41 of the plurality of switching elements 40 and have an L-shaped configuration that is bent toward the plurality of lead connection holes 53. The second frame 90 has a plurality of lead insertion holes 95 in the potting material filling section 130 at positions corresponding to the plurality of lead connection holes 53, through which the plurality of leads 42 are inserted. The plurality of leads 42 are inserted through the plurality of lead insertion holes 95 and supported by the potting material 131.

[0076] Since the lead 42 inserted through the lead insertion hole 95 is covered and supported by the potting material 131, the lead 42 can be protected and electrically insulated.

[0077] Refer to Figure 9. The first frame 80 has multiple lead straightening holes 151 through which multiple leads 42 are inserted, at positions corresponding to multiple lead connection holes 53. By inserting the multiple leads 42 into the multiple lead straightening holes 151, the positions of the multiple leads 42 are straightened to match the multiple lead connection holes 53.

[0078] The multiple lead insertion holes 95 in the second frame 90 allow the positions of the leads 42 of the multiple switching elements 40 to be aligned, and the multiple lead straightening holes 151 in the first frame 80 correct any deformation such as bending of each lead 42, allowing them to be easily guided into the multiple lead connection holes 53.

[0079] Refer to Figures 6A and 6B. The electric compressor 10 has a mounting portion 24b that is erected from the cooling wall 24 toward the first frame 80. A single unit 60 is composed of a printed circuit board 50, a first frame 80 attached to the printed circuit board 50, a second frame 90 attached to the first frame 80, and a plurality of switching elements 40 that hold a plurality of leads 42 on the second frame 90. The single unit 60 is fastened to the mounting portion 24b by fastening members 87.

[0080] A single unit 60 is formed by integrating the printed circuit board 50, the first frame 80, the second frame 90, and a plurality of switching elements 40. By simply fastening this unit 60 to the mounting portion 24b with fastening members 87, the unit 60 can be assembled to the cooling wall 24, thereby improving ease of assembly.

[0081] Refer to Figure 2. The first frame 80 has a plurality of biasing portions 140 that contact a plurality of switching bodies 41 and bias the cooling wall 24. The plurality of biasing portions 140 are made up of a part 81 (first substrate 81) of the first frame 80 and are in direct contact with the plurality of switching bodies 41 without overlapping with the first frame 80 in the biasing direction Rc.

[0082] The biasing unit 140 that biases the switching element 40 to the cooling wall 24 is made up of a part 81 (first substrate 81) 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.

[0083] Refer to Figure 9. 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).

[0084] The electrical insulation between each lead 42 can be improved by a simple configuration that increases the creepage distance L2 between adjacent leads 42, using multiple inner wall surfaces 152a that form multiple recesses 152 into which multiple leads 42 are individually inserted.

[0085] Refer to Figure 9. 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.

[0086] Refer to Figure 4. The first frame 80 is equipped with a positioning unit 121 that positions each of the multiple switching bodies 41 in the direction Rb (second direction Rb) in which the multiple switching elements 40 are aligned. The positioning unit 121 of the first frame 80 positions the multiple switching bodies 41 in the direction Rb (second direction Rb) in which the multiple switching elements 40 are aligned. The flexible potting material 131 (see Figure 2) allows the multiple switching elements 40, which are simply made by attaching multiple leads 42 to the second frame 90, to be stably positioned in the direction Rb (second direction Rb) in which the multiple switching elements 40 are aligned.

[0087] Furthermore, the present invention is not limited to each embodiment, 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.

[0088] The electric compressor 10 of the present invention is suitable for use in a refrigeration cycle.

[0089] 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, 50...Printed circuit board, 53...Lead connection hole, 60...Unit (inverter unit), 80...First frame, 86...Mounting part, 87...Fastening member, 90...Second frame, 95...Lead insertion hole, 121...Potting part, 130...Potting material filling part, 131...Potting material, 140...Biasing part, 151...Lead straightening hole, 152...Recess (tapered recess), 152a...Inner wall surface forming a recess, 153...Cylindrical portion (bulging portion), L1...Spatial distance, L2...Creepage distance, Rb...Direction in which multiple switching elements are aligned.

Claims

1. The device 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 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), 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. The electric compressor (10) comprises a plurality of switching elements (40) including a plurality of switching bodies (41) located between the printed circuit board (50) and the cooling wall (24), and a plurality of leads (42) extending from the plurality of switching bodies (41) to the printed circuit board (50) and connected thereto, wherein the electric compressor also comprises a frame (70) located between the printed circuit board (50) and the cooling wall (24) and attached to the printed circuit board (50), and the plurality of switching elements (40) are held in the frame (70) by the plurality of leads (42) being attached to the frame (70) by a potting material (131) having electrical insulating and flexible properties.

2. The electric compressor according to claim 1, wherein the frame (70) comprises a first frame (80) located between the printed circuit board (50) and the plurality of switching elements (40) and attached to the printed circuit board (50), and a second frame (90) located between the first frame (80) and the cooling wall (24) and attached to the first frame (80), the plurality of leads (42) being attached to the second frame (90) within the frame (70) by the potting material (131), and the first frame (80) biasing the plurality of switching bodies (41) toward the cooling wall (24).

3. The electric compressor according to claim 2, further comprising a potting material filling section (130) for filling with the potting material (131), wherein the potting material filling section (130) is partitioned by the plurality of switching bodies (41) and the second frame (90), and the plurality of leads (42) are held by the second frame (90) via the potting material (131) filled in the potting material filling section (130).

4. 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, the plurality of leads (42) extend from the side surface (41c) of each of the plurality of switching bodies (41) of the plurality of switching elements (40) and have an L-shaped configuration that is bent toward the plurality of lead connection holes (53), the second frame (90) has a plurality of lead insertion holes (95) in the potting material filling section (130) at positions corresponding to the plurality of lead connection holes (53), the plurality of leads (42) are inserted through the plurality of lead insertion holes (95) and supported by the potting material (131), the electric compressor according to claim 3.

5. The electric compressor according to claim 4, 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).

6. The electric compressor according to claim 2, further comprising a mounting portion (24b) erected from the cooling wall (24) toward the first frame (80), wherein a single unit (60) is formed by the printed circuit board (50), the first frame (80) attached to the printed circuit board (50), the second frame (90) attached to the first frame (80), and the plurality of switching elements (40) whose plurality of leads (42) are held by the second frame (90), and the single unit (60) is fastened to the mounting portion (24b) by a fastening member (87).

7. The electric compressor according to claim 2, wherein the first frame (80) has a plurality of biasing portions (140) that abut against the plurality of switching bodies (41) and bias the cooling wall (24), and the plurality of biasing portions (140) are formed from a part of the first frame (80) and are in direct contact with the plurality of switching bodies (41) without overlapping with the first frame (80) in the biasing direction (Rc).

8. The electric compressor according to claim 5, 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).

9. The electric compressor according to claim 8, wherein the inner wall surface (152a) forming the recess (152) is tapered from the switching element (40) side toward the lead straightening hole (151).

10. The electric compressor according to claim 2, wherein the first frame (80) is provided with a positioning unit (121) for positioning each of the plurality of switching bodies (41) in the direction (Rb) in which the plurality of switching elements (40) are aligned.

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