Heat dissipation structure for surface-mounted heating component

Abstract

To provide a heat dissipation structure for a surface-mounted heating component capable of dissipating heat from a surface-mounted heating component in simple configuration.SOLUTION: A heat dissipation structure for a surface-mounted heating component comprises: a circuit board 31 which includes a conductor pattern 32 on a first mounting surface 31a; a surface-mounted resistor 33 which is surface-mounted on the first mounting surface 31a and connected with the conductor pattern 32; a motor housing 13 and an inverter cover 14 in which the circuit board 31 is accommodated; a bus bar 50 which is connected with the conductor pattern 32 and joined to the circuit board 31 and extends from the circuit board 31 toward the motor housing 13; and a potting material 51 which insulates the bus bar 50 and the motor housing 13 while joining the bus bar 50 to the motor housing 13.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a heat dissipation structure for a surface-mounted heat-generating component. [Background technology]

[0002] 2. Description of the Related Art Conventionally, surface-mounted heat-generating components are mounted on the mounting surface of a circuit board having a conductor pattern. 2. Description of Related Art A heat dissipation structure for a surface-mounted heat-generating component is disclosed in, for example, Patent Document 1. The chip-type heat generating component described in Patent Document 1 has functional electrodes for electrical connection and electrodes for heat dissipation.

[0003] In addition, in Patent Document 1, the printed circuit board on which the chip-type heat-generating component is mounted includes a functional electrode pad, a ground layer, and a heat-dissipation electrode pad connected to the ground layer by a through-hole. The ground layer is connected to a heat sink.

[0004] The functional electrodes of the chip-type heat-generating component are soldered to the functional electrode pads, and the heat-dissipating electrodes are soldered to the heat-dissipating electrode pads. Heat generated in the chip-type heat-generating component is transferred from the heat-dissipating electrodes to the heat-dissipating electrode pads. The heat-dissipating electrode pads are connected to the ground layer via through-holes, so the heat from the heat-dissipating electrodes is transferred to the heat sink via the ground layer. The heat transferred to the heat sink is released into the air, dissipating the heat from the chip-type heat-generating component. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 6-169189 Summary of the Invention [Problem to be solved by the invention]

[0006] In the heat dissipation structure for a chip-type heat-generating component described in Patent Document 1, it is necessary to provide a heat dissipation ground layer, through holes, and heat dissipation pads on the printed circuit board, and it is also necessary to provide heat dissipation electrodes on the chip-type heat-generating component itself. Therefore, the heat dissipation structure for a chip-type heat-generating component described in Patent Document 1 requires heat dissipation configurations for both the chip-type heat-generating component and the printed circuit board. [Means for solving the problem]

[0007] The heat dissipation structure for a surface-mounted heat-generating component that solves the above-mentioned problems comprises a circuit board having a conductor pattern on its mounting surface, a surface-mounted heat-generating component that is surface-mounted on the mounting surface and connected to the conductor pattern, a metal housing that houses the circuit board, a heat dissipation member that is connected to the conductor pattern and joined to the circuit board and extends from the circuit board toward the metal housing, and an insulating member that joins the heat dissipation member to the metal housing and insulates the heat dissipation member from the metal housing.

[0008] According to this, heat generated by the surface-mounted heat-generating component is transferred to the conductor pattern on the circuit board. The heat transferred to the conductor pattern is then transferred from the heat dissipation member to the metal housing via the insulating member, and the heat generated by the surface-mounted heat-generating component is thus released to the metal housing. Even the heat dissipation member connected to the conductor pattern is insulated from the metal housing by the insulating member. Therefore, heat can be released from the surface-mounted heat-generating component with a simple configuration that simply joins the heat dissipation member extending from the circuit board to the metal housing via the insulating member. In other words, heat can be released from the surface-mounted heat-generating component with a simple configuration, without providing a heat dissipation structure for each of the circuit board and the surface-mounted heat-generating component.

[0009] In the heat dissipation structure for a surface-mounted heat-generating component, the insulating member may be a potting material. This potting material is not only easy to handle, but also has heat dissipation properties in addition to the insulating properties of an insulating material, making it possible to easily realize a heat dissipation structure for a surface-mounted heat-generating component and efficiently dissipate heat transferred to the heat dissipation material from the insulating material.

[0010] In the heat dissipation structure for surface-mounted heat-generating components, a plurality of the surface-mounted heat-generating components may be mounted on the mounting surface of the circuit board, and the conductor pattern and the heat dissipation member connected to the conductor pattern may be positioned on the mounting surface between at least two of the surface-mounted heat-generating components.

[0011] According to this, heat generated by the multiple surface-mounted heat-generating components is released into the atmosphere from the surface of each surface-mounted heat-generating component, but heat is difficult to release and tends to build up in the area on the mounting surface sandwiched between at least two surface-mounted heat-generating components. Because the conductor pattern and heat dissipation member are located in this area where heat tends to build up, it is possible to prevent heat from building up in the area on the mounting surface sandwiched between at least two surface-mounted heat-generating components.

[0012] In the heat dissipation structure for a surface-mounted heat-generating component, a plurality of the heat dissipation members may be provided on the mounting surface of the circuit board, and the conductor pattern and the plurality of heat dissipation members may be provided on the mounting surface in positions that sandwich the surface-mounted heat-generating component.

[0013] With this, heat from the surface-mounted heat-generating components is transferred to each of the heat-dissipating members via the conductor pattern, and the heat is then dissipated from each heat-dissipating component to the metal housing, allowing for efficient heat dissipation from the surface-mounted heat-generating components.

[0014] In the heat dissipation structure for a surface-mounted heat-generating component, the metal casing may include a protrusion that protrudes toward the circuit board, and the heat dissipation member may extend from the circuit board toward the protrusion and be joined to the protrusion by the insulating member.

[0015] This reduces the distance from the circuit board to the metal housing compared to when there is no protrusion, allowing the heat dissipation components to be shorter, resulting in more stable installation of the heat dissipation components.

[0016] In the heat dissipation structure for a surface-mounted heat-generating component, the heat dissipation member may include a main body extending from the circuit board toward the metal housing, and heat dissipation fins extending from the main body.

[0017] According to this, the surface area of the heat dissipation member is increased by the heat dissipation fins, and the heat dissipation performance can be improved. [Effects of the Invention]

[0018] According to the present invention, heat can be dissipated from a surface-mounted heat-generating component with a simple configuration. [Brief explanation of the drawings]

[0019] [Figure 1] FIG. 1 is a partially cutaway cross-sectional view showing an electric compressor. [Figure 2] FIG. 2 is a diagram schematically illustrating an inverter. [Figure 3] FIG. 3 is a diagram schematically illustrating an inverter. [Figure 4] FIG. 4 is a diagram showing a heat dissipation structure for a surface-mounted heat-generating component according to a modified example. [Figure 5] FIG. 5 is a diagram showing a modified example of the heat dissipation member. DETAILED DESCRIPTION OF THE INVENTION

[0020] An embodiment of a heat dissipation structure for a surface-mounted heat-generating component will now be described with reference to Figures 1 to 3. The heat dissipation structure for a surface-mounted heat-generating component of this embodiment is used, for example, in an electric compressor of an air conditioner for a vehicle.

[0021] <Electric compressor> As shown in FIG. 1, the electric compressor 10 has a cylindrical housing 11. The housing 11 has a discharge housing 12, a motor housing 13, and an inverter cover 14. The discharge housing 12, the motor housing 13, and the inverter cover 14 are made of metal. The metal is, for example, aluminum. The discharge housing 12 has a discharge port 12h. The electric compressor 10 has a rotating shaft 15, a compression unit 16, an electric motor 17, and an inverter 30.

[0022] The motor housing 13 has a plate-shaped end wall 13a, a cylindrical peripheral wall 13b, and a cylindrical extension wall 13c. The peripheral wall 13b extends cylindrically from the outer periphery of the end wall 13a. The extension wall 13c extends cylindrically from the outer periphery of the end wall 13a toward the opposite side of the peripheral wall 13b. The motor housing 13 has an intake port 13h. The intake port 13h is formed in the peripheral wall 13b of the motor housing 13. The intake port 13h is formed in a portion of the peripheral wall 13b that is located closer to the end wall 13a. The end wall 13a is provided with a protrusion 52 and a boss 53. Each of the protrusion 52 and the boss 53 extends cylindrically from the end wall 13a toward the opposite side of the peripheral wall 13b. There may be one or more bosses 53; however, in this embodiment, there are three bosses 53.

[0023] The rotating shaft 15 is disposed inside the peripheral wall 13b of the motor housing 13. The rotating shaft 15 is rotatably supported by the housing 11. The rotating shaft 15 is accommodated in the housing 11 with the axial direction, which is the direction in which the rotation axis of the rotating shaft 15 extends, coinciding with the axial direction of the peripheral wall 13b of the motor housing 13. Therefore, the axial direction of the rotating shaft 15 coincides with the axial direction of the housing 11.

[0024] The compression section 16 compresses the refrigerant as a fluid. The compression section 16 is disposed inside the peripheral wall 13b of the motor housing 13. The compression section 16 is driven by the rotation of the rotary shaft 15. The compression section 16 is, for example, a scroll type configured with a fixed scroll and an orbiting scroll (not shown). The fixed scroll is fixed to the inner peripheral surface of the peripheral wall 13b of the motor housing 13. The orbiting scroll revolves relative to the fixed scroll as the rotary shaft 15 rotates.

[0025] The electric motor 17 is disposed inside the peripheral wall 13b of the motor housing 13. The compression unit 16 and the electric motor 17 are disposed side by side in the axial direction of the rotary shaft 15. The electric motor 17 is disposed closer to the end wall 13a of the motor housing 13 than the compression unit 16. Therefore, the space inside the peripheral wall 13b of the motor housing 13 between the compression unit 16 and the end wall 13a forms a motor chamber 18 that accommodates the electric motor 17. Thus, the housing 11 has the motor chamber 18. The motor chamber 18 is in communication with the intake port 13h.

[0026] The electric motor 17 drives the compression unit 16 by rotating the rotary shaft 15. The electric motor 17 has a cylindrical stator 20 and a cylindrical rotor 21. The rotor 21 is disposed inside the stator 20. The rotor 21 rotates integrally with the rotary shaft 15. The rotor 21 has a rotor core 21a fixed to the rotary shaft 15 and a plurality of permanent magnets (not shown) provided on the rotor core 21a. The stator 20 surrounds the rotor 21. The stator 20 has a cylindrical stator core 20a and a motor coil 22 wound around the stator core 20a.

[0027] A first end of the external refrigerant circuit 23 is connected to the suction port 13h. A second end of the external refrigerant circuit 23 is connected to the discharge port 12h. The refrigerant flowing through the external refrigerant circuit 23 is drawn into the motor chamber 18 through the suction port 13h. The refrigerant drawn into the motor chamber 18 is compressed in the compression section 16 as the compression section 16 is driven. The refrigerant compressed in the compression section 16 is discharged into the external refrigerant circuit 23 through the discharge port 12h. The refrigerant discharged from the discharge port 12h to the external refrigerant circuit 23 passes through a heat exchanger and an expansion valve of the external refrigerant circuit 23 and returns to the motor chamber 18 through the suction port 13h. The electric compressor 10 and the external refrigerant circuit 23 constitute a vehicle air conditioning system 24.

[0028] The inverter cover 14 is plate-shaped. The inverter cover 14 is fixed to the extension wall 13c of the motor housing 13 while closing the opening of the extension wall 13c. The end wall 13a and extension wall 13c of the motor housing 13, together with the inverter cover 14, define an inverter chamber 19. Therefore, the housing 11 has the inverter chamber 19. The end wall 13a of the motor housing 13 is a partition wall that separates the motor chamber 18 from the inverter chamber 19. The compression unit 16, the electric motor 17, and the inverter 30 are arranged in this order in the axial direction of the rotating shaft 15.

[0029] The inverter 30 drives the electric motor 17. The inverter 30 is housed in the inverter chamber 19. <Conductive pin> 3, the electric compressor 10 has three conductive pins 46. The three conductive pins 46 penetrate the end wall 13a and electrically connect the electric motor 17 and the circuit board 31. The end wall 13a has through holes 47 through which the conductive pins 46 pass.

[0030] <Circuit board> 1 and 2, the inverter 30 has a circuit board 31. The circuit board 31 is supported by three bosses 53. A fixing member 54 that passes through the circuit board 31 is screwed into each boss 53. The circuit board 31 is fixed to the motor housing 13 by screwing the fixing members 54 into each boss 53.

[0031] The circuit board 31 has a first mounting surface 31a and a second mounting surface 31b that are opposite to each other in the thickness direction. The circuit board 31 is housed in the inverter chamber 19 with the first mounting surface 31a facing the inverter cover 14 and the second mounting surface 31b facing the end wall 13a of the motor housing 13. Therefore, the circuit board 31 is supported by the boss 53 with the second mounting surface 31b in contact with the boss 53. The thickness direction of the circuit board 31 coincides with the axial direction of the rotating shaft 15. Therefore, the thickness direction of the circuit board 31 coincides with the axial direction of the housing 11. The circuit board 31 is housed in the inverter chamber 19 as part of the inverter 30. The inverter chamber 19 is formed by the motor housing 13 and the inverter cover 14, and the motor housing 13 and the inverter cover 14 form a metal housing that houses the circuit board 31. Further, the end wall 13 a of the motor housing 13 as a metal casing includes a protrusion 52 that protrudes toward the second mounting surface 31 b of the circuit board 31 .

[0032] <Circuit boards and mounted components> 2 and 3, a conductor pattern 32, a switching element 34, a capacitor 35, and a surface-mount resistor 33 serving as a surface-mount heat-generating component are mounted on the circuit board 31. Note that the conductor pattern 32 is not shown in detail, and only a portion of it is illustrated. The conductor pattern 32 is provided on the first mounting surface 31a. Therefore, the circuit board 31 has the conductor pattern 32 on the first mounting surface 31a.

[0033] A plurality of switching elements 34 are mounted on the circuit board 31. Specifically, a power module 36, in which a plurality of switching elements 34 are modularized, is mounted on the circuit board 31. The power module 36 is disposed between the second mounting surface 31b of the circuit board 31 and the end wall 13a of the motor housing 13.

[0034] The power module 36 has a module body 37 and a plurality of lead portions 38. A plurality of switching elements 34 are embedded inside the module body 37. The module body 37 is fixed to the end wall 13a of the motor housing 13. Each switching element 34 performs a switching operation to convert DC voltage from an external power source into AC voltage. The AC voltage converted by the switching operation of each switching element 34 is then supplied to the electric motor 17 as a drive voltage.

[0035] The capacitor 35 is disposed between the second mounting surface 31b of the circuit board 31 and the end wall 13a of the motor housing 13. The capacitor 35 is a filter element that reduces noise contained in the input current from the outside.

[0036] The surface-mounted resistor 33 is provided on the first mounting surface 31a. The capacitor 35 and the surface-mounted resistor 33 are connected in parallel by a conductor pattern 32, which is not shown in detail.

[0037] As shown in FIG. 3, eight surface-mount resistors 33 are surface-mounted on the first mounting surface 31a. All of the surface-mount resistors 33 are electrically connected by conductor patterns 32, only a portion of which is shown. The number of surface-mount resistors 33 mounted on the circuit board 31 may be changed as appropriate. The eight surface-mount resistors 33 are arranged so that two rows R of four surface-mount resistors 33 are connected in series by the conductor patterns 32. The rows R of four series-connected surface-mount resistors 33 are connected in parallel by conductor patterns 32, not shown in detail. The surface-mount resistors 33 are connected in parallel to a capacitor 35, and are used for self-discharge of the circuit. The surface-mount resistors 33 are heat-generating components that generate heat when current flows through them.

[0038] As shown in FIGS. 2 and 3, the heat dissipation structure of the surface mount resistor 33 includes a bus bar 50 as a heat dissipation member and a potting material 51 as an insulating member. <Busbar> The busbar 50 is joined to the circuit board 31 and extends from the circuit board 31 toward the protrusion 52 of the metal housing. The busbar 50 is, for example, a rectangular copper plate with high thermal conductivity. The longitudinal direction of the busbar 50 extends between the circuit board 31 and the end wall 13a. The longitudinal direction Z of the busbar 50 coincides with the axial direction of the rotation shaft 15. The length L1 of the busbar 50 in the longitudinal direction Z, i.e., the length L1 of the busbar 50 in the axial direction, is longer than the shortest distance between the first mounting surface 31a and the protrusion 52. The thickness direction Y of the busbar 50 coincides with the direction in which the rows R of the surface-mount resistors 33 are arranged. The length L2 of the busbar 50 in the thickness direction Y is shorter than the shortest distance between the two rows R of the surface-mount resistors 33.

[0039] The direction perpendicular to the longitudinal direction Z and the thickness direction Y of the bus bar 50 is defined as the lateral direction X. The length L3 of the bus bar 50 in the lateral direction X is longer than the length of the surface mount resistor 33 in the lateral direction X. A first end 50a of the busbar 50 in the longitudinal direction Z penetrates the conductor pattern 32 of the circuit board 31. The first end 50a of the busbar 50 protrudes further toward the first mounting surface 31a than the conductor pattern 32, and the first end 50a is joined to the conductor pattern 32 by solder 55. The busbar 50 is electrically connected to the conductor pattern 32 by the solder 55 and is joined to the circuit board 31.

[0040] Busbar 50 penetrates circuit board 31 from the first mounting surface 31a side and extends from second mounting surface 31b toward protrusion 52. Therefore, busbar 50 extends from second mounting surface 31b, which is the surface opposite first mounting surface 31a, toward protrusion 52. Second end 50b of busbar 50 in longitudinal direction Z is joined to protrusion 52 by potting material 51 provided on protrusion 52.

[0041] <Potting material> Here, the potting material 51 will be described. The potting material 51 is made of, for example, urethane resin, epoxy resin, or silicone resin. The potting material 51 has insulating properties as well as heat dissipation properties. The potting material 51 is used by applying a liquid material and then hardening it. Specifically, the potting material 51 is formed by applying a liquid potting material to the end surface of the protrusion 52 on the second mounting surface 31b side and then hardening it. The potting material 51 connects the second end 50b of the busbar 50 to the protrusion 52 on the motor housing 13 while insulating the busbar 50 from the protrusion 52 of the motor housing 13. The heat dissipation structure of the surface-mount resistor 33 includes a circuit board 31, the surface-mount resistor 33, the motor housing 13, the busbar 50, and the potting material 51.

[0042] 3, the bus bar 50 and a portion of the conductor pattern 32 connected to the bus bar 50 are located in the center of the area where multiple surface-mounted resistors 33 are mounted, more specifically, between rows R of the surface-mounted resistors 33 and at the center in the direction in which the rows R extend. Therefore, the bus bar 50 and a portion of the conductor pattern 32 are provided in an area surrounded by eight surface-mounted resistors 33. More specifically, the conductor pattern 32 and the bus bar 50 connected to the conductor pattern 32 are provided on the first mounting surface 31a at a position sandwiched between the four surface-mounted resistors 33 on both sides in the plate thickness direction Y.

[0043] Furthermore, bus bar 50 is disposed slightly closer to the edge of circuit board 31 than the center of circuit board 31. An imaginary line L is set to connect two bosses 53 that face each other in the thickness direction Y. Imaginary line L passes through the center of circuit board 31. Bus bar 50 is disposed at a position away from imaginary line L in the short direction X.

[0044] [Operation of the embodiment] Heat generated in the surface-mounted resistor 33 is transferred to the conductive pattern 32 of the circuit board 31. The heat transferred to the conductive pattern 32 is transferred from the bus bar 50 through the potting material 51 to the motor housing 13, including the protrusion 52. Therefore, the heat generated in the surface-mounted resistor 33 is released to the motor housing 13. Even the bus bar 50 connected to the conductive pattern 32 is insulated from the motor housing 13 by the potting material 51.

[0045] [Effects of the embodiment] The effects of this embodiment will be described. (1) Heat can be dissipated from the surface-mount resistor 33 with a simple configuration in which the bus bar 50 extending from the circuit board 31 is joined to the motor housing 13 with the potting material 51. In other words, heat can be dissipated from the surface-mount resistor 33 with a simple configuration without providing a complex heat dissipation configuration to each of the circuit board 31 and the surface-mount resistor 33.

[0046] (2) Because the bus bar 50 is connected to the conductor pattern 32, the bus bar 50 is joined to the circuit board 31 without ensuring an insulation distance between the bus bar 50 and the surface-mount resistor 33. Therefore, the circuit board 31 can be made smaller than when, for example, the bus bar 50 is joined to the circuit board 31 by separating the bus bar 50 from the surface-mount resistor 33 along the surface direction of the circuit board 31 in order to ensure an insulation distance between the surface-mount resistor 33 and the bus bar 50.

[0047] (3) On the first mounting surface 31a of the circuit board 31, in the area surrounded by the eight surface-mounted resistors 33, specifically in the position sandwiched between the rows R of the surface-mounted resistors 33, heat is difficult to dissipate between adjacent surface-mounted resistors 33, and heat tends to build up. Because the bus bar 50 and the conductor pattern 32 are located in this position where heat tends to build up, heat can be prevented from building up in the area surrounded by the eight surface-mounted resistors 33 on the first mounting surface 31a.

[0048] Furthermore, there is an insertion type resistor that is used by inserting leads into the circuit board 31, but the insertion type resistor is less costly than the surface mount resistor 33. The surface mount resistor 33, which is less expensive than the insertion type resistor, has poorer heat dissipation properties than the insertion type resistor. However, by employing the heat dissipation structure of the embodiment, the surface mount resistor 33 can dissipate heat while keeping costs down.

[0049] Additionally, in order to promote heat dissipation from the surfaces of the surface-mount resistors 33, it is also possible to apply a coolant to each of the surface-mount resistors 33 and bring the coolant into contact with the inverter cover 14. However, this method requires applying the coolant to all of the surface-mount resistors 33, which makes the application process very complicated. In contrast, with the heat dissipation structure of the embodiment, the only application process that is required is to apply the potting material 51 to the protrusions 52, which simplifies the application process.

[0050] (4) The potting material 51 is not only easy to handle, but also has insulating and heat dissipation properties. Therefore, the potting material 51 can easily realize a heat dissipation structure for the surface-mount resistor 33, and can efficiently dissipate heat transferred to the bus bar 50 from the potting material 51.

[0051] (5) The circuit board 31 is supported at three points on the periphery by three bosses 53, and the power module 36 is mounted on the second mounting surface 31b of the circuit board 31. For this reason, a certain degree of vibration occurs in the circuit board 31. The bus bar 50 is disposed near the center of the circuit board 31. The bus bar 50 connects the circuit board 31 to the end wall 13a of the motor housing 13. For this reason, the bus bar 50 can easily suppress vibration of the circuit board 31.

[0052] (6) The motor housing 13 is formed with a protrusion 52 that protrudes toward the second mounting surface 31b of the circuit board 31. The bus bar 50 extending from the circuit board 31 is joined to the protrusion 52 by a potting material 51. Compared to when the protrusion 52 is not formed, the distance from the second mounting surface 31b of the bus bar 50 to the protrusion 52 is shorter, and therefore the length L1 of the bus bar 50 in the longitudinal direction Z is shorter. This allows for stable installation of the bus bar 50. Furthermore, considering the same amount of material, the thickness of the bus bar 50 can be made thicker than when the protrusion 52 is not formed, thereby improving the vibration suppression effect of the bus bar 50.

[0053] (7) Heat from the surface-mounted resistors 33 is collected in the conductor patterns 32 and the bus bars 50, but is also released to the end walls 13a of the motor housing 13. In other words, the heat from the surface-mounted resistors 33 is transferred to the motor housing 13, which has a large heat dissipation area, and therefore the heat can be efficiently released from the surface-mounted resistors 33.

[0054] [Example of change] The above-described embodiments can be modified as follows: The above-described embodiments and the following modifications can be combined with each other within the scope of technical compatibility.

[0055] The protrusion 52 does not have to be formed on the motor housing 13. A plurality of bus bars 50 may be provided on the first mounting surface 31a of the circuit board 31, and the conductor patterns 32 and the plurality of bus bars 50 may be disposed on the first mounting surface 31a at positions that sandwich the surface-mounted heat-generating component. For example, as shown in FIG. 4 , if the surface-mounted heat-generating component is a power module 36, the conductor patterns 32 may be disposed so as to sandwich the power module 36, and a pair of bus bars 50 may be connected to the conductor patterns 32 and joined to the circuit board 31. In this manner, heat from the power module 36 is transferred to each of the plurality of bus bars 50 via the conductor patterns 32. Heat is then released from each bus bar 50 to the motor housing 13, allowing efficient heat dissipation from the power module 36.

[0056] The number of surface mount resistors 33 mounted on the first mounting surface 31a may be one. The bus bar 50 does not have to be surrounded by a plurality of surface-mount resistors 33. For example, the bus bar 50 may be arranged outside the row R of the surface-mount resistors 33.

[0057] The surface-mounted heat-generating component does not have to be the surface-mounted resistor 33 as long as it is connected to the conductor pattern 32 and generates heat. The insulating member does not have to be the potting material 51. Any material that can insulate the bus bar 50 from the metal housing may be used. For example, the insulating member may be a ceramic material or a thermosetting resin.

[0058] The busbar 50 does not have to be rectangular. For example, as shown in FIG. 5 , the busbar 50 may include a main body 501 extending straight from the second mounting surface 31b of the circuit board 31 toward the end wall 13a of the metal housing, and heat dissipation fins 502 extending from the main body 501. The heat dissipation fins 502 extend in a direction intersecting both surfaces of the main body 501 in the thickness direction Y, but the direction in which the heat dissipation fins 502 extend from the main body 501 can be changed as appropriate. The heat dissipation fins 502 may be provided at the second end 50b of the busbar 50 and midway along the longitudinal direction of the main body 501. The heat dissipation fins 502 provided at the second end 50b of the busbar 50 may be embedded in the potting material 51. In this configuration, the surface area of the busbar 50 is larger than when the heat dissipation fins 502 are not provided. The heat dissipation fins 502 embedded in the potting material 51 improve the heat dissipation performance to the potting material 51, and the heat dissipation fins 502 located midway along the longitudinal direction improve the heat dissipation performance to the atmosphere, thereby improving the heat dissipation performance.

[0059] The bus bar 50 may extend from the circuit board 31 toward the end wall 13a, bend toward the extending wall 13c, and be joined to the extending wall 13c. In this case, the motor housing 13 including the extending wall 13c serves as the metal casing to which the bus bar 50 is joined. Alternatively, the bus bar 50 may extend from the circuit board 31 toward the inverter cover 14 and be joined to the inverter cover 14. In this case, the inverter cover 14 serves as the metal casing to which the bus bar 50 is joined.

[0060] The surface-mounted heat-generating component may be mounted on the second mounting surface 31b of the circuit board 31. In the embodiment, the electric compressor 10 is used in the vehicle air conditioner 24, but the present invention is not limited to this. For example, the electric compressor 10 may be mounted on a fuel cell vehicle and compress air as a fluid to be supplied to the fuel cell.

[0061] The application of the heat dissipation structure for a surface-mounted heat-generating component is not limited to electric compressors. For example, the heat dissipation structure for a surface-mounted heat-generating component may be applied to an inverter device for an electric motor. In this case, the metal housing serves as a case for housing the inverter device.

[0062] The heat dissipation member does not have to be a rectangular plate like the bus bar 50, and may be, for example, a long bolt. The bus bar 50 does not have to be electrically connected to the conductive pattern 32.

[0063] [Note] The technical ideas that can be understood from the above-described embodiment and modified examples will be described. <Aspect 1> a circuit board having a conductor pattern on a mounting surface; a surface-mounted heat-generating component surface-mounted on the mounting surface and connected to the conductor pattern; a metal housing that houses the circuit board; a heat dissipation member connected to the conductor pattern and joined to the circuit board and extending from the circuit board toward the metal housing; and an insulating member that joins the heat dissipation member to the metal housing and insulates the heat dissipation member from the metal housing.

[0064] <Aspect 2> 2. The heat dissipation structure for a surface-mounted heat-generating component according to claim 1, wherein the insulating member is a potting material.

[0065] <Aspect 3> A heat dissipation structure for a surface-mounted heat-generating component according to aspect 1 or aspect 2, characterized in that a plurality of the surface-mounted heat-generating components are mounted on the mounting surface of the circuit board, and the conductor pattern and the heat dissipation member connected to the conductor pattern are positioned on the mounting surface between at least two of the surface-mounted heat-generating components.

[0066] <Aspect 4> A heat dissipation structure for a surface-mounted heat-generating component according to aspect 1 or aspect 2, characterized in that a plurality of the heat dissipation components are provided on the mounting surface of the circuit board, and the conductor pattern and the plurality of heat dissipation components are positioned on the mounting surface to sandwich the surface-mounted heat-generating component.

[0067] <Aspect 5> The heat dissipation structure for a surface-mounted heat-generating component according to any one of Aspects 1 to 4, characterized in that the metal casing includes a protrusion protruding toward the circuit board, and the heat dissipation member extends from the circuit board toward the protrusion and is joined to the protrusion by the insulating member.

[0068] <Aspect 6> A heat dissipation structure for a surface-mounted heat-generating component according to any one of aspects 1 to 5, characterized in that the heat dissipation member comprises a main body extending from the circuit board toward the metal casing, and heat dissipation fins extending from the main body. [Explanation of symbols]

[0069] 13...motor housing forming a metal casing, 14...inverter cover forming a metal casing, 31...circuit board, 31a...first mounting surface as a mounting surface, 31b...second mounting surface, 32...conductor pattern, 33...surface-mounted resistor as a surface-mounted heat-generating component, 50...bus bar as heat dissipation member, 51...potting material as an insulating member, 52...protrusion, 501...main body, 502...heat dissipation fin.

Claims

1. a circuit board having a conductor pattern on a mounting surface; a surface-mounted heat-generating component that is surface-mounted on the mounting surface and connected to the conductor pattern; a metal housing that houses the circuit board; a heat dissipation member connected to the conductor pattern and joined to the circuit board, and extending from the circuit board toward the metal housing; a heat dissipation structure for a surface-mounted heat-generating component, comprising: an insulating member that joins the heat dissipation member to the metal case and insulates the heat dissipation member from the metal case;

2. 2. The heat dissipation structure for a surface-mounted heat-generating component according to claim 1, wherein the insulating member is a potting material.

3. 3. The heat dissipation structure for a surface-mounted heat-generating component according to claim 1, wherein a plurality of the surface-mounted heat-generating components are mounted on the mounting surface of the circuit board, and the conductor pattern and the heat dissipation member connected to the conductor pattern are positioned on the mounting surface so as to be sandwiched between at least two of the surface-mounted heat-generating components.

4. 3. The heat dissipation structure for a surface-mounted heat-generating component according to claim 1, wherein a plurality of the heat dissipation members are provided on the mounting surface of the circuit board, and the conductor pattern and the plurality of heat dissipation members are positioned on the mounting surface to sandwich the surface-mounted heat-generating component.

5. 3. The heat dissipation structure for a surface-mounted heat-generating component according to claim 1, wherein the metal housing includes a protrusion that protrudes toward the circuit board, and the heat dissipation member extends from the circuit board toward the protrusion and is joined to the protrusion by the insulating member.

6. 3. The heat dissipation structure for a surface-mounted heat-generating component according to claim 1, wherein the heat dissipation member comprises a main body extending from the circuit board toward the metal housing, and heat dissipation fins extending from the main body.

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