ELECTRONIC DEVICE

An electronic device includes a housing made of metal, a circuit board on which a circuit pattern is formed, and an electronic component mounted on the circuit board. The housing has a boss that is formed in a columnar shape protruding toward the circuit board and to which the circuit board is fixed by a fastening member made of metal. The boss has a fastening hole into which the fastening member is screwed and a contact surface with which a ground pattern in the circuit pattern is in contact. The contact surface has a recessed surface that is recessed toward the fastening hole. The circuit board has a protruding surface that protrudes such that the ground pattern is in contact with the recessed surface.

BACKGROUND ART

This application claims priority to Japanese Patent Application No. 2023-059026 filed on Mar. 31, 2023, the entire disclosure of which is incorporated herein by reference.

The present disclosure relates to an electronic device.

There is known an electronic device including a circuit board, electronic components mounted on the circuit board, and a metal housing accommodating the circuit board and the electronic components, for example. A circuit pattern is formed on the circuit board. A part of the circuit pattern is grounded through the housing to serve as a ground pattern. With this configuration, noise is transmitted between the ground pattern of the circuit board and the housing.

A housing of an electronic device described in Japanese Patent Application Publication No. 2004-327784 has columnar bosses protruding toward the circuit board. The circuit board is fixed to the bosses by fastening members made of metal. Each of the bosses includes a fastening hole into which the corresponding fastening member is screwed and a contact surface with which the circuit board is in contact.

When fastening members by which the ground pattern of the circuit board is grounded through the housing are employed in the electronic device described in the Publication, contact areas between the contact surfaces of the bosses and the ground pattern of the circuit board are small. As a result, noise may not be suitably transmitted between the ground pattern of the circuit board and the housing.

SUMMARY

In accordance with an aspect of the present disclosure, there is provided an electronic device that includes a housing made of metal, a circuit board that is accommodated in the housing and on which a circuit pattern is formed, and an electronic component that is accommodated in the housing and mounted on the circuit board. The housing has a boss that is formed in a columnar shape protruding toward the circuit board and to which the circuit board is fixed by a fastening member made of metal. The boss has a fastening hole into which the fastening member is screwed and a contact surface with which a ground pattern in the circuit pattern is in contact. The ground pattern is grounded through the housing. The contact surface has a recessed surface that is recessed toward the fastening hole from an outer peripheral surface of the boss. The circuit board has a protruding surface that protrudes such that the ground pattern is in contact with the recessed surface.

Other aspects and advantages of the disclosure will become apparent from the following description, taken in conjunction with the accompanying drawings, illustrating by way of example the principles of the disclosure.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The following will describe an inverter as an embodiment of an electronic device with reference to the drawings. The inverter of the present embodiment is configured to drive a motor of an electric compressor used for a vehicle air conditioner.

As illustrated inFIG.1, a vehicle air conditioner10includes an electric compressor11and an external refrigerant circuit12. A refrigerant as fluid is supplied from the external refrigerant circuit12to the electric compressor11. The external refrigerant circuit12includes, for example, a heat exchanger and an expansion valve. The vehicle air conditioner10performs heating and cooling of a vehicle interior by the electric compressor11that compresses the refrigerant and the external refrigerant circuit12through which heat is exchanged from or to the refrigerant and the refrigerant is expanded.

The vehicle air conditioner10includes an air-conditioning ECU13. The air-conditioning ECU13controls the entire vehicle air conditioner10. The air-conditioning ECU13is configured to obtain a temperature inside a vehicle100and a setting temperature of the vehicle air conditioner10. The air-conditioning ECU13sends various commands such as ON/OFF commands to the electric compressor11, based on parameters such as the temperature inside the vehicle100and the setting temperature of the vehicle air conditioner10.

<Basic Configuration of Electric Compressor>

The electric compressor11includes a housing14. The housing14is made of a metal material with heat transfer properties, for example, aluminum. That is, the housing14is made of metal. The housing14is connected to a body of the vehicle100as a ground point.

The housing14includes a suction housing15and a discharge housing16. The suction housing15is assembled to the discharge housing16. The suction housing15has an end wall15aformed in a plate shape and a peripheral wall15bformed in a tubular shape. The peripheral wall15bis formed in the tubular shape extending from an outer peripheral edge of the end wall15a. The discharge housing16is assembled to the suction housing15while closing an opening of the suction housing15. With this assembly, an inner space is formed in the housing14.

The housing14has a suction port14aand a discharge port14b. The suction port14ais formed in the peripheral wall15bof the suction housing15. The suction port14ais located closer to the end wall15athan the discharge housing16in the peripheral wall15bof the suction housing15. The refrigerant is sucked from the external refrigerant circuit12into the housing14through the suction port14a. The discharge port14bis formed in the discharge housing16. The refrigerant is discharged to the external refrigerant circuit12through the discharge port14b.

The electric compressor11includes a rotary shaft17, a compression part18, and a motor19. The rotary shaft17, the compression part18, and the motor19are accommodated in the housing14. The rotary shaft17is rotatably supported by the housing14. The rotary shaft17is disposed in the housing14with an axial direction of the rotary shaft17coinciding with an axial direction of the peripheral wall15b.

The compression part18is accommodated in the suction housing15. The compression part18is a scroll type compression part including a fixed scroll fixed in the suction housing15and an orbiting scroll disposed so as to face the fixed scroll. Illustrations of the fixed scroll and the orbiting scroll are omitted. The compression part18is located closer to the discharge port14bthan the suction port14ain the suction housing15. The compression part18is connected to the rotary shaft17. The compression part18is driven by the rotation of the rotary shaft17to compress the refrigerant.

The motor19is accommodated in the suction housing15. The motor19is disposed between the compression part18and the end wall15ain the suction housing15. The motor19includes a rotor20and a stator21. The stator21has a stator core22formed in a cylindrical shape, a u-phase coil23u, a v-phase coil23v, and a w-phase coil23w.

Each of the u-phase coil23u, the v-phase coil23v, and the w-phase coil23wis wound around the stator core22. For example, the u-phase coil23u, v-phase coil23v, and w-phase coil23ware connected in Y-connection. This aspect of the connection of the u-phase coil23u, the v-phase coil23v, and the w-phase coil23wis not limited to the Y-connection and may be selected as appropriate. For example, the three coils may be connected in a delta-connection.

The rotor20is formed in a cylindrical shape. The rotor20is fixed to the rotary shaft17. As a result, the rotary shaft17is formed so as to rotate integrally with the rotor20. The stator21is fixed to the peripheral wall15bof the suction housing15. The rotor20and the stator21face each other in a radial direction of the rotary shaft17.

The rotor20rotates when a current flows through the u-phase coil23u, the v-phase coil23v, and the w-phase coil23win a specified pattern. The rotary shaft17rotates with the rotation of the rotor20. This drives the compression part18. Thus, the motor19drives the compression part18. The refrigerant flowing through the external refrigerant circuit12is sucked into the housing14through the suction port14a. The compression part18compresses the refrigerant sucked into the housing14. The compressed refrigerant is discharged into the external refrigerant circuit12through the discharge port14b.

The electric compressor11includes an inverter30. The inverter30drives the motor19. The housing14has an inverter cover31and a cover bottom wall33. The inverter30includes the inverter cover31and the cover bottom wall33. In other words, the inverter30has a part of the housing14made of metal. The cover bottom wall33and the inverter cover31are made of a metal material such as aluminum. The cover bottom wall33is formed in a plate shape extending along the end wall15a. The inverter cover31is attached to the cover bottom wall33and the end wall15aby bolts32. The cover bottom wall33cooperates with the inverter cover31to form an inverter accommodation chamber S1.

The electric compressor11includes a connector27. The connector27is electrically connected to a power storage device28mounted on the vehicle100. The connector27is provided on the inverter cover31. The connector27protrudes from the inverter cover31. The power storage device28is a power source from which a power is supplied to any devices mounted on the vehicle100. The power storage device28is a DC power source. The power storage device28is, for example, a rechargeable battery or a capacitor.

The inverter30has a circuit board34. The circuit board34is accommodated in the inverter accommodation chamber S1. That is, the circuit board34is accommodated in the housing14. The circuit board34is spaced from the cover bottom wall33at a predetermined distance in the axial direction of the rotary shaft17and faces the cover bottom wall33. The circuit board34is accommodated in the inverter accommodation chamber S1with a thickness direction of the circuit board34coinciding with the axial direction of the rotary shaft17.

The inverter30includes an inverter circuit35and a noise reduction section36. The inverter circuit35is configured to convert DC power to AC power. The noise reduction section36is provided on an input side of the inverter circuit35. The noise reduction section36, for example, reduces common mode noise and normal mode noise in a DC power that is to be input to the inverter circuit35. Electronic components and switching elements that constitute the inverter circuit35and the noise reduction section36are mounted on the circuit board34and accommodated in the housing14.

The u-phase switching elements Qu1, Qu2are connected in series. Anode between the u-phase switching elements Qu1, Qu2is connected to the u-phase coil23u. A series connected body of the u-phase switching elements Qu1, Qu2is electrically connected to both the connection lines EL1, EL2.

The v-phase switching elements Qv1, Qv2are connected in series. A node between the v-phase switching elements Qv1, Qv2is connected to the v-phase coil23v. A series connected body of the v-phase switching elements Qv1, Qv2is electrically connected to both the connection lines EL1, EL2.

The w-phase switching elements Qw1, Qw2are connected in series. A node between the w-phase switching elements Qw1, Qw2is connected to the w-phase coil23w. A series connected body of the w-phase switching elements Qw1, Qw2is electrically connected to both the connection lines EL1, EL2.

The inverter30includes a control unit37. The control unit37controls switching operation of each of the switching elements Qu1to Qw2. For example, the control unit37is formed of one or more processors (control circuits) that are operated according to computer programs (software) and/or one or more dedicated hardware circuits. The processor includes a CPU and a memory such as a RAM and a ROM. The memory stores the program codes or commands for causing the processor to execute various processes. The memory, that is, a computer readable medium, includes any available medium that is accessible by a general-purpose computer or a dedicated computer.

The control unit37is electrically connected to the air-conditioning ECU13through the connector27. The control unit37periodically turns each of the switching elements Qu1to Qw2on and off in response to commands from the air-conditioning ECU13. In detail, the control unit37performs pulse width modulation control (PWM control) of the switching elements Qu1to Qw2in response to the commands from air-conditioning ECU13. More specifically, the control unit37generates control signals using a carrier signal and command voltage signals (comparison signal). The control unit37performs the ON/OFF control of each of the switching element Qu1to Qw2using the generated control signals to convert DC power to AC power.

The noise reduction section36includes a common mode choke coil38, normal mode choke coils42, and smoothing capacitors39. The smoothing capacitors39cooperate with the common mode choke coil38and the normal mode choke coils42to form a low-pass filter40. The low-pass filter40is provided on the connection lines EL1and EL2. The low-pass filter40is provided between the connector27and the inverter circuit35for its circuitry. The common mode choke coil38and the normal mode choke coils42are provided on the connection lines EL1, EL2.

The smoothing capacitors39are each provided between the connector27and the common mode choke coil38and between the common mode choke coil38and the inverter circuit35for its circuitry. The smoothing capacitors39are X capacitors connected in parallel with the inverter circuit35. The smoothing capacitors39are electrically connected to both connection lines EL1and EL2.

The noise reduction section36has two Y-capacitors41. The two Y-capacitors41are connected in series. A node between the two Y-capacitors41is grounded through the housing14. The two Y-capacitors41are provided between the common mode choke coil38and the inverter circuit35for its circuitry. The two Y-capacitors41are connected in series with the common mode choke coil38and the normal mode choke coils42. The two Y-capacitors41are connected in parallel with the smoothing capacitors39. The two Y-capacitors41are provided between the smoothing capacitor39and the inverter circuit35for its circuitry.

The Y-capacitors41in this embodiment correspond to electronic components. Accordingly, the inverter30has the Y-capacitors41as the electronic components. The Y-capacitors41as the electronic components are mounted on the circuit board34. The Y-capacitors41as the electronic components are accommodated in the housing14.

The common mode choke coil38and the normal mode choke coils42suppress that high frequency noise generated on a side of the vehicle100is transmitted to the inverter circuit35of the electric compressor11. The common mode choke coil38reduces common mode noise. The normal mode choke coils42reduces normal mode noise.

<Details of Circuit Board>

As illustrated inFIG.3, the circuit board34has a first surface34acorresponding to a back surface of the circuit board34and a second surface34bcorresponding to a front surface, which is opposite to the first surface34a. The circuit board34is a glass epoxy board. A first ground pattern134dis formed on the first surface34aand serves as a ground pattern grounded through the housing14. A second ground pattern234dis formed on the second surface34band grounded through the housing14. An inner layer ground pattern334dmay be also formed in an inner layer of the circuit board34and grounded through the housing14. For example, the inner layer ground pattern334dconnects one part of the first ground pattern134dformed in portions of the circuit board34on which the Y-capacitors41are mounted and another part of the first ground pattern134dformed in a portion of the circuit board34on which the inverter circuit35is mounted.

A circuit pattern34dis formed on the circuit board34. A metal layer34cis provided on the first surface34aand forms a part of the circuit pattern34dincluding the first ground pattern134d. The metal layer34cis also provided on the second surface34band forms a part of the circuit pattern34dincluding the second ground pattern234d. The electronic components, the switching elements, and the like that constitute the inverter circuit35and the noise reduction section36are mounted on the circuit pattern34d. The first ground pattern134dis connected to a ground line of the electronic components, the switching elements, and the like that constitute the inverter circuit35and the noise reduction section36. The second ground pattern234dis connected to a ground line of the electronic components, the switching elements, and the like that constitute the inverter circuit35and the noise reduction section36.

As illustrated inFIG.3, the first ground pattern134dis partly overlapped with a part of the second ground pattern234din the thickness direction of the circuit board34. The first ground pattern134dis located near the cover bottom wall33of the housing14. The second ground pattern234dis located near the inverter cover31, that is, on an opposite side of the cover bottom wall33in an axial direction of the housing14. The first ground pattern134dand the second ground pattern234dare electrically connected through a plurality of through hole vias43.

The circuit board34has through holes34hextending in the thickness direction of the circuit board34. The through holes34hextend from the first surface34ato the second surface34b. The through holes34hare round holes in plan view, for example. The through holes34hopens in the first ground pattern134dand the second ground pattern234d. In detail, the through holes34hare located in portions of the first ground pattern134ddistanced from edges of the first ground pattern134dand portions of the second ground pattern234ddistanced from edges of the second ground pattern234d. The through holes34hopens toward the cover bottom wall33of the housing14on a side of the first surface34a. The through holes34hopens toward the inverter cover31on a side of the second surface34b.

The circuit board34has slits34sextending in the thickness direction of the circuit board34. The slits34sopen in the first surface34aand the second surface34b. The slits34sopen toward the cover bottom wall33of the housing14on the side of the first surface34a. The slits34sopen toward the inverter cover31on the side of the second surface34b.

The slits34sare formed in portions of the circuit board34except for a portion of the circuit board34between the through holes34hand the portions on which the Y-capacitors41as the electronic components are mounted. In detail, the slits34sare each formed in a semicircular shape extending along the through holes34hin plan view, for example. The slits34sare formed at positions of the circuit board34except for on the circuit pattern34d. The slits34sopen in the first surface34aat the positions of the circuit board34except for on the first ground pattern134dand the circuit pattern34dconnecting the portions on which the Y-capacitors41are mounted and the first ground pattern134d. The slits34sopen in the second surface34bat positions of the circuit board34except for on the second ground pattern234d. That is, there is a positional relationship around the through holes34hin the circuit board34between a portion in which the slits34sare not formed and the portions of the circuit board34on which the Y-capacitors41are mounted such that they are connected by an imaginary line extending along the first surface34a.

Bosses61are formed in the housing14. The bosses61protrude toward the circuit board34. More specifically, the bosses61protrude from the cover bottom wall33of the housing14toward the first surface34aof the circuit board34. The bosses61are each formed in a columnar shape. A direction in which the bosses61protrude from the cover bottom wall33of the housing14coincides with the thickness direction of the circuit board34. The bosses61are located at positions where the bosses61are not overlapped with the slits34sof the circuit board34in plan view. The bosses61are located near the respective slits34sand face the respective through hole vias43.

Each of the bosses61has a contact surface62that is in contact with the first surface34a. When an end of the boss61near the cover bottom wall33of the housing14is defined as a base end, the contact surface62is located at a tip of the boss61opposite to the base end across the boss61in the direction in which the bosses61protrude. The contact surface62is formed in a circular shape in plan view.

The bosses61each have a fastening hole61h. The fastening hole61hopens in the contact surface62. More specifically, the fastening hole61his open in a center of the contact surface62in plan view. The fastening hole61hextends from contact surface62toward the housing14, more specifically, to the cover bottom wall33of the housing14. The fastening hole61his defined by a cylindrical peripheral surface having an internal thread inside the boss61. The fastening hole61hdoes not face the through hole vias43.

The contact surface62has an outer peripheral portion62aon an outer peripheral side of an opening of the fastening hole61h. The outer peripheral portion62ahas a recessed surface64that is recessed toward the fastening hole61hfrom an outer peripheral side of the boss61. In other words, the contact surface62has the recessed surface64. The contact surface62has an inner peripheral portion62bbetween the opening of the fastening hole61hand the outer peripheral portion62a. The inner peripheral portion62bis located on an inner peripheral side of the outer peripheral portion62ain the contact surface62. The inner peripheral portion62bis located closer to the cover bottom wall33of the housing14than the outer peripheral portion62ain the thickness direction of the circuit board34. The outer peripheral portion62ais concave so as to approach the cover bottom wall33of the housing14as the outer peripheral portion62aextends toward the inner peripheral portion62b. As a result, the recessed surface64is concave toward the fastening hole61hfrom the outer peripheral side of the boss61. In plan view, the outer peripheral portion62ais formed in a ring shape. In side view, an edge63of the outer peripheral portion62aprojects toward the first surface34aof the circuit board34. In plan view, the edge63of the outer peripheral portion62ais formed in a ring shape.

The inner peripheral portion62bis formed flat so as to extend in a direction perpendicular to the direction in which the bosses61protrude. The inner peripheral portion62bis formed in a ring shape in plan view. The inner peripheral portion62bis formed flat in side view. The inner peripheral portion62bis formed flat such that the inner peripheral portion62bextends toward the fastening hole61h.

The inverter30includes fastening members70made of metal. The circuit board34is fixed to the housing14by the fastening members70. The fastening members70bring the first ground pattern134dinto contact with the contact surface62to ground the first ground pattern134dthrough the housing14. In other words, the first ground pattern134din the circuit pattern34d, which is the ground pattern to be grounded through the housing14, is brought into contact with the contact surface62. The fastening members70do not bring the second ground pattern234dinto contact with the contact surface62, but the second ground pattern234dis grounded through the housing14by the fastening members70. That is, the second ground pattern234dis electrically connected to the housing14through the through hole vias43. The fastening members70each have a head71and a threaded portion72extending from the head71. The head71is, for example, formed in a circular flat plate shape. The threaded portion72is, for example, formed in a columnar shape. An external thread is formed on an outer peripheral surface of the threaded portion72. The threaded portion72is inserted into the corresponding through hole34hfrom an opening of the through hole34hin the second surface34b. Thus, the fastening members70are inserted into the respective through holes34h. The head71is in contact with the second ground pattern234d. A direction in which the threaded portion72extends from the head71coincides with the thickness direction of the circuit board34. The threaded portion72is screwed into the corresponding fastening hole61h. That is, the fastening members70are screwed into the respective fastening holes61h. Thus, the fastening members70are fixed to the respective bosses61. The circuit board34is fixed to the bosses61by the fastening members70. When the fastening members70are fixed to the bosses61, the circuit board34is fastened to the housing14. Accordingly, the circuit board34is fixed to the housing14by the fastening members70. The fastening members70bring the first ground pattern134dinto contact with the contact surface62to ground the first ground pattern134dthrough the housing14. The fastening members70do not bring the second ground pattern234dinto contact with the contact surface62, but the second ground pattern234dis grounded through the housing14by the fastening members70. In other words, the second ground pattern234dis connected to the housing14through the fastening members70.

The inner peripheral portion62bis overlapped with the head71of the corresponding fastening member70through the circuit board34in plan view. The inner peripheral portion62bextends in parallel with the head71. In other words, the head71is overlapped with a surface of the circuit board34that extends flat. In plan view, the head71is overlapped with the entire inner peripheral portion62b. In plan view, the head71may be overlapped with only a part of the inner peripheral portion62b.

<Contact of the Circuit Board into Contact Surface>

The circuit board34fixed to the housing14by the fastening members70is deformed and extends along the contact surface62. In detail, the circuit board34is in contact with the outer peripheral portion62awhile being convex along the outer peripheral portion62a. That is, the circuit board34has a protruding surface75that protrudes such that the first ground pattern134dis in contact with the recessed surface64. The protruding surface75is deformed between each of the slits34sand the corresponding through hole34hand extends through the contact surface62. In addition, the circuit board34is in contact with the inner peripheral portion62bwhile extending in the flat plate shape along the inner peripheral portion62b. Thus, the circuit board34is fixed to the housing14while being in contact with the contact surface62of each of the bosses61. A portion of the circuit board34in contact with the contact surface62of the boss61is the first ground pattern134dformed on the first surface34aof the circuit board34. A portion of the circuit board34in contact with the head71is the second ground pattern234dformed on the second surface34bof the circuit board34. A size of the first ground pattern134dis designed such that the contact surface62is entirely in contact with the first ground pattern134d. A size of the second ground pattern234dis designed such that the second ground pattern234dis entirely in contact with the head71.

The slits34sare each located on an outer peripheral side of the corresponding through hole34hof the circuit board34. The slit34sis located on an outer peripheral side of a portion of the circuit board34in contact with the contact surface62. That is, the slit34sis located on an outer peripheral side of the protruding surface75. The protruding surface75extends from the slit34sto the through hole34h. The slit34sis closer to the corresponding through hole34sthan the Y-capacitors. The slit34sis formed on the opposite side of the portions on which the Y-capacitors41are mounted across the through hole34hin plan view.

Thus, when the fastening members70are fastened to the respective bosses61, the circuit board34is deformed to be brought into contact with the contact surface62and fixed to the housing14. Thus, the first ground pattern134dis deformed to be grounded through the housing14. The second ground pattern234dis also deformed and electrically connected to the housing14through the fastening members70. Noise is transmitted from the first ground pattern134dto the housing14, and then, transmitted from the housing14to the body of the vehicle100. Noise is transmitted from the second ground pattern234dto the housing14through the fastening members70, and then, transmitted from the housing14to the body of the vehicle100.

Operation in the Embodiment

The following will describe an operation of the embodiment together with a method of fastening the fastening members70to the respective bosses61.

As illustrated inFIG.4, the threaded portion72inserted into the through hole34his screwed into the fastening hole61hof each of the bosses61. Here, the circuit board34is not deformed along the contact surface62during a process in which the threaded portion72is screwed into the fastening hole61h. Accordingly, the circuit board34extends in the flat plate shape on the bosses61. The first surface34aof the circuit board34is in contact with the edge63of the outer peripheral portion62aof each of the bosses61, for example.

As illustrated inFIG.3, as the threaded portion72is screwed into the corresponding fastening hole61h, the circuit board34is pushed toward the contact surface62by the head71, which deforms the circuit board34along the contact surface62. The circuit board34is convex along the outer peripheral portion62ato be brought into contact with the outer peripheral portion62a. A portion of the circuit board34around the through hole34his held between the head71and the inner peripheral portion62bof the corresponding boss61. This makes the portion of the circuit board34around the through hole34hin the flat plate shape along the inner peripheral portion62band the portion is brought into contact with the inner peripheral portion62b. Thus, the circuit board34is brought into contact with the contact surface62of each of the bosses61.

Advantageous Effects of the Embodiment

The following will describe advantageous effects of the present embodiment.

(1) The contact surface62has the recessed surface64that is recessed toward the fastening hole61hfrom the outer peripheral side of the boss61. In the contact surface62, the inner peripheral portion62bis located closer to the cover bottom wall33of the housing14than the outer peripheral portion62ain the thickness direction of the circuit board34. The outer peripheral portion62ais concave so as to approach the cover bottom wall33of the housing14as the outer peripheral portion62aextends toward the inner peripheral portion62b. The inner peripheral portion62bis formed flat so as to extend in the direction perpendicular to the direction in which the bosses61protrude. On the other hand, the circuit board34fixed to the housing14by the fastening members70extends along the contact surface62. The circuit board34has the protruding surface75that protrudes such that the first ground pattern134dis in contact with the recessed surface64. The first ground pattern134dof the circuit board34is in contact with the outer peripheral portion62awhile being convex along the outer peripheral portion62a. The first ground pattern134dof the circuit board34is in contact with the inner peripheral portion62bwhile extending in a flat plate shape along the inner peripheral portion62b. Accordingly, as compared with a case where the contact surface62entirely extends flat, a contact area between the contact surface62of each of the bosses61and the first ground pattern134dof the circuit board34is increased without increasing a width of the boss61in a radial direction thereof.

(2) The inner peripheral portion62bis overlapped with the head71of each of the fastening members70through the circuit board34in plan view. In addition, the outer peripheral portion62ais not overlapped with the head71through the circuit board34in plan view. With this configuration, when the circuit board34is held between the inner peripheral portion62band the head71, the circuit board34is convex along the outer peripheral portion62a. Accordingly, the first ground pattern134dof the circuit board34is suitably brought into contact with the contact surface62.

(3) The circuit board34has the slits34sextending in the thickness direction of the circuit board34. The slits34sare each provided near the outer peripheral portion62a. With this configuration, when the circuit board34is convex along the contact surface62, openings of the slits34sare widened, thereby causing the circuit board34to be deformed suitably. The slits34sopen in the first surface34aat the positions of the circuit board34except for on the first ground pattern134dand the circuit pattern34dconnecting the portions on which the Y-capacitors41are mounted and the first ground pattern134d. The slits34sopen in the second surface34bat the positions of the circuit board34except for on the second ground pattern234d. This configuration suppresses interference with the transmission of the noise and other components.

(4) The edge63of the outer peripheral portion62aprojects toward the first surface34aof the circuit board34, and thus, when the circuit board34is convex along the contact surface62, the circuit board34is deformed using the edge63of the outer peripheral portion62aas a starting point, so that the circuit board34is suitably deformed.

The above-described embodiment may be modified as follows. The above-described embodiment and the following modifications may be combined with each other as long as they do not technically contradict each other.

As illustrated inFIG.5, the outer peripheral portion62aneed not be concave in side view, but may be inclined in side view, that is, formed in a taper shape. In short, the recessed surface64may be inclined toward the fastening hole61hfrom the outer peripheral side of the boss61. In this case, the outer peripheral portion62ais formed in a ring shape in plan view.

The edge63of the outer peripheral portion62aneed not project over an entire periphery of the edge63, but the edge63of the outer peripheral portion62amay partly project toward the first surface34a. In this case, a portion of the edge63of the outer peripheral portion62athat does not project may be formed flat, for example, such that the portion extends in the direction perpendicular to the direction in which the bosses61protrude.

The edge63of the outer peripheral portion62aneed not project over the entire periphery of the edge63, but the edge63of the outer peripheral portion62amay be chamfered over the entire periphery of the edge63.

The slits34sneed not extend through the circuit board34. In short, the slits34sonly need be open in one of the first surface34aand the second surface34bof the circuit board34.

The slits34sneed not be formed in the circuit board34.

The circuit board34may be a metal-based board instead of the glass epoxy board.

The inner peripheral portion62bmay be concave such that the inner peripheral portion62bis continuous with the outer peripheral portion62a. In addition, the inner peripheral portion62bmay be inclined such that the inner peripheral portion62bis continuous with the outer peripheral portion62a. In this case, the contact surface62is recessed toward the cover bottom wall33of the housing14as the contact surface62extends toward an opening edge of the fastening hole61h.

In the housing14, the portion that accommodates the circuit board34is formed integrally with the portion that accommodates the compression part18and the motor19; however, they may be separately provided by increasing the number of housings.

Static electricity other than the noise may be transmitted by bringing the circuit board34into contact with the contact surface62of the boss61.

The peripheral surface by which the through hole34hof the circuit board34is defined may have a metal film that electrically connects the first surface34aand the second surface34b.

The first ground pattern134dof the circuit board34may be in contact with the outer peripheral portion62aand need not be in contact with the inner peripheral portion62b. In this case, an area of the outer peripheral portion62ais larger than that of the inner peripheral portion62b. In addition, a contact area between the first ground pattern134dof the circuit board34and the outer peripheral portion62ais larger than a contact area between the first ground pattern134dof the circuit board34and the contact surface62when the contact surface62entirely extends flat.

The compression part18need not be of a scroll type. For example, the compression part18may be of a piston type or a vane type.

The electronic device is used in the vehicle air conditioner10; however, the present disclosure is not limited thereto. For example, the electronic device may be mounted on a fuel cell vehicle. The electric compressor11including the electronic device may compress air as fluid supplied to a fuel cell by the compression part18.