CN111835218A

CN111835218A - Inverter unit

Info

Publication number: CN111835218A
Application number: CN202010272592.8A
Authority: CN
Inventors: 岩上直记; 渡边裕
Original assignee: Nidec Elesys Corp
Current assignee: Nidec Elesys Corp
Priority date: 2019-04-19
Filing date: 2020-04-09
Publication date: 2020-10-27
Also published as: JP2020178494A

Abstract

The present invention provides an inverter unit, one mode of which converts direct current into alternating current and supplies the alternating current to a motor. The inverter unit has: a grounded housing provided with a housing chamber opened to the outside; a circuit board located in the housing chamber; and a bus bar connecting the circuit board and the housing. The circuit board has: a switching element; a connector connected to an external power supply device; an electrode connected to the bus bar; and a ground pattern connected to the switching element, the connector, and the electrode. The ground pattern is provided with a coil element having an impedance and a capacitor element having a capacitance, which make it easier for the current from the switching element to flow to the electrode than the connector.

Description

Inverter unit

Technical Field

The present invention relates to an inverter unit.

Background

An inverter unit having an inverter and a case housing the inverter for controlling a motor is known. Patent document 1 discloses an electronic device that reduces common mode noise by means of a washer and a fixing screw.

Patent document 1: japanese patent laid-open publication No. 2017-191902

However, in the conventional technology, when a large component is disposed below the circuit board, or when the distance between the inverter case as the GND (ground) and the circuit board is long, it is difficult to adopt a structure using a fixing screw.

Disclosure of Invention

The present invention has been made in view of the above points, and an object thereof is to provide an inverter unit capable of suppressing adverse effects due to common mode noise.

According to the 1 st aspect of the present invention, there is provided an inverter unit that converts a direct current into an alternating current and supplies the alternating current to a motor, the inverter unit including: a grounded housing provided with a housing chamber opened to the outside; a circuit board located in the receiving chamber; and a bus bar electrically connecting the circuit board and the housing, the circuit board having: a switching element; a connector connected to an external power supply device; an electrode connected to the bus bar; and a ground pattern connected to the switching element, the connector, and the electrode, the ground pattern being provided with a coil element having impedance and a capacitor element having capacitance, which make a current from the switching element flow to the electrode more easily than the connector.

According to one embodiment of the present invention, an inverter unit capable of easily reducing common mode noise is provided.

Drawings

Fig. 1 is a plan view of an inverter unit according to an embodiment.

Fig. 2 is a schematic cross-sectional view of an inverter unit of one embodiment along line II-II of fig. 1.

Fig. 3 is a plan view of an inverter unit according to an embodiment in which the 1 st cover and the 2 nd cover are omitted.

Fig. 4 is a simple circuit diagram showing patterns of a ground system (GND system) of the switching element 71 and the connector 72 in the control substrate 21.

Fig. 5 is a sectional view of the periphery of ground electrode 74 in control substrate 21.

Fig. 6 is a top view of the capacitor cover 26.

Fig. 7 is a partial perspective view of the capacitor cover 26 to which the 3 rd bus bar 34 is fixed.

Fig. 8 is a sectional view of the periphery of the fixing wall 26C of the capacitor cover 26.

Description of the reference symbols

1: an inverter unit; 10: a housing; 11: a 1 st housing chamber (housing chamber); 21: a control substrate (circuit board); 23: a capacitor; 26: a capacitor cover; 26A: a top wall; 26B: a side wall (1 st side wall); 26C: a fixed wall; 26D: a step portion; 26E: a side wall (2 nd side wall); 34: a 3 rd bus bar (bus bar); 35a, 35 b: a holding portion (1 st holding portion); 36: a widening section; 37: a notch portion; 38: 1 st shaft part; 39: a holding portion (2 nd holding portion); 65: an annular portion; 66: a linear portion; 71: a switching element; 72: a connector; 74: a ground electrode (electrode); 75: a coil element; 76: and a capacitor element.

Detailed Description

Hereinafter, an inverter unit according to an embodiment of the present invention will be described with reference to the drawings. The scope of the present invention is not limited to the following embodiments, and may be arbitrarily changed within the scope of the technical idea of the present invention. In the drawings below, in order to facilitate understanding of each structure, the actual structure may be different from the scale, the number, or the like of each structure.

In the following description, the direction of gravity is defined based on the positional relationship when the inverter unit 1 is mounted on a vehicle on a horizontal road surface. In the drawings, an XYZ coordinate system is appropriately shown as a three-dimensional orthogonal coordinate system. In the XYZ coordinate system, the Z-axis direction represents the vertical direction (i.e., the vertical direction), + Z direction is the upper side (the opposite side to the direction of gravity), and-Z direction is the lower side (the direction of gravity). The X-axis direction is a direction orthogonal to the Z-axis direction, and indicates the front-rear direction of the vehicle on which the inverter unit 1 is mounted. The Y-axis direction is a direction perpendicular to both the X-axis direction and the Z-axis direction, and indicates a width direction (left-right direction) of the vehicle.

Hereinafter, an inverter unit 1 and a motor unit 3 having the inverter unit 1 according to an exemplary embodiment of the present invention will be described with reference to the drawings.

Fig. 1 is a plan view of the inverter unit 1.

The inverter unit 1 is disposed in the motor unit 3. The motor unit 3 includes an inverter unit 1, a motor 2, and a motor case 3 a. The motor unit 3 may have a reduction gear (not shown) for reducing the rotation speed of the motor 2.

The motor unit 3 of the present embodiment is mounted on a vehicle having a motor as a power source, such as a Hybrid Electric Vehicle (HEV), a plug-in hybrid electric vehicle (PHV), or an Electric Vehicle (EV), and is used as a power source for these vehicles.

The motor housing 3a has a storage space for storing the motor 2 therein. The motor 2 is housed in the housing space of the motor case 3 a. The inverter unit 1 is fixed to the outer peripheral surface of the motor case 3 a.

The motor 2 is supplied with an alternating current from the inverter unit 1. The motor 2 is controlled by the inverter unit 1. The motor 2 has: a rotor 2a that rotates about a motor axis J extending in a horizontal direction; and a stator 2b located radially outside the rotor 2 a. The coil wire of the stator 2b is connected to the inverter unit 1.

Fig. 2 is a schematic sectional view of the inverter unit 1 along line II-II of fig. 1. Fig. 3 is a plan view of the inverter unit 1 with illustration of the 1 st cover 40 and the 2 nd cover 50 omitted.

The inverter unit 1 converts a direct current into an alternating current and supplies the alternating current to the motor 2. As shown in fig. 2, the inverter unit 1 includes: a case 10, a control substrate (circuit board) 21, a power supply substrate 22, a capacitor 23, an Insulated Gate Bipolar Transistor (hereinafter, referred to as IGBT)24, a 1 st bus bar 31, a 2 nd bus bar 32, a 3 rd bus bar (bus bar) 34, a 1 st cover 40, and a 2 nd cover 50.

A housing space 13 is provided inside the housing 10. The control board 21, the power supply board 22, the capacitor 23, the IGBT 24, the 1 st bus bar 31, the 2 nd bus bar 32, the bus bar holder 33, and the 3 rd bus bar 34 are housed in the housing space 13.

The housing space 13 is divided into a 1 st housing chamber 11 and a 2 nd housing chamber 12. That is, the housing 10 is provided with a 1 st housing chamber 11 and a 2 nd housing chamber 12. The 1 st housing chamber 11 and the 2 nd housing chamber 12 are open to the outside. The openings of the 1 st housing chamber 11 and the 2 nd housing chamber 12 face upward. That is, the 1 st housing chamber 11 and the 2 nd housing chamber 12 open in the same direction. The opening directions of the 1 st housing chamber 11 and the 2 nd housing chamber 12 coincide with the vertical direction. The 1 st housing chamber 11 and the 2 nd housing chamber 12 are adjacent to each other.

Control board 21, power supply board 22, capacitor 23, IGBT 24, and 3 rd bus bar 34 are housed in 1 st housing chamber 11. As shown in fig. 3, the 1 st bus bar 31 and the 2 nd bus bar 32 are housed across the 1 st housing chamber 11 and the 2 nd housing chamber 12.

The case 10 is made of, for example, an aluminum alloy having conductivity. The housing 10 is grounded. The case 10 has a 1 st bottom wall 10a, a 2 nd bottom wall 10b, a side wall 10c, and a partition wall 10 d. The housing space 13 is a space surrounded by the 1 st bottom wall 10a, the 2 nd bottom wall 10b, and the side wall 10 c.

The side wall portion 10c has a substantially rectangular ring shape when viewed in the vertical direction. The side wall portion 10c surrounds the housing space 13 from the horizontal direction. A 1 st cover 40 and a 2 nd cover 50 are fixed to an upper end surface 10ca of the side wall portion 10 c.

The 1 st and 2 nd

bottom wall portions

10a and 10b are located at the lower end of the side wall portion 10 c. The 1 st bottom wall 10a and the 2 nd bottom wall 10b are located below the housing space 13. The 1 st bottom wall portion 10a is located below the 1 st accommodation chamber 11. The 2 nd bottom wall portion 10b is located below the 2 nd accommodation chamber 12.

The 2 nd bottom wall portion 10b is located above the 1 st bottom wall portion 10 a. Therefore, the vertical dimension (dimension along the opening direction) of the 2 nd housing chamber 12 is smaller than the vertical dimension of the 1 st housing chamber 11. The volume of the 2 nd housing chamber 12 is smaller than the volume of the 1 st housing chamber 11. A part of the 1 st bus bar 31 and a part of the 2 nd bus bar 32 are mainly received in the 2 nd receiving chamber 12. In the 2 nd housing chamber 12, the plate thickness direction of the 1 st bus bar 31 and the 2 nd bus bar 32 coincides with the vertical direction. According to the present embodiment, the size of the 2 nd housing chamber 12 in the vertical direction is made smaller than the 1 st housing chamber 11, and the entire inverter unit 1 can be made smaller.

The partition wall 10d divides the storage space 13 into a 1 st storage chamber 11 and a 2 nd storage chamber 12. The partition wall 10d is provided with a partition wall opening 10da that allows the 1 st housing chamber 11 and the 2 nd housing chamber 12 to communicate with each other. The 1 st bus bar 31 and the 2 nd bus bar 32 pass through the partition wall opening 10 da.

As shown in fig. 2, the control board 21 is located in the 1 st accommodation chamber 11. The control board 21 is connected to the motor 2 to control the motor 2. For example, when the motor unit 3 includes an encoder such as a resolver, the control board 21 performs feedback control of the rotation speed of the motor 2 based on the rotation speed of the motor 2 measured by the encoder.

The power supply substrate 22, the capacitor 23, and the IGBT 24 are located in the 1 st housing chamber 11. The capacitor 23 and the IGBT 24 are connected to the power supply substrate 22. The power supply substrate 22, the capacitor 23, and the IGBT 24 constitute an inverter 25. The inverter 25 is connected to the external power supply device 9 via the 1 st bus bar 31 and the 2 nd bus bar 32. The external power supply device 9 is, for example, a secondary battery mounted on a vehicle. The inverter 25 converts a direct current supplied from the external power supply device 9 into an alternating current.

As shown in fig. 2, the 1 st cover 40 covers the opening of the 1 st housing chamber 11. The 1 st cover 40 has a plate shape. The 1 st cover 40 is formed by press working. The thickness direction of the 1 st cover 40 coincides with the opening direction (vertical direction in the present embodiment) of the 1 st accommodation chamber 11.

The No. 1 cover 40 has an upper surface 40a and a lower surface 40 b. The lower surface 40b constitutes a part of the inner surface of the 1 st accommodation chamber 11. The lower surface 40b is in contact with the upper end surface 10ca of the housing 10. The upper surface 40a is a surface facing the opposite side of the lower surface 40 b. The upper surface 40a is a surface facing the opening direction of the 1 st housing chamber 11.

As shown in fig. 1, the 1 st cover 40 is fixed to the housing 10 at its peripheral edge by a plurality of fixing screws 18. A plurality of through holes (not shown) penetrating the 1 st cover 40 in the plate thickness direction are provided in the peripheral edge portion of the 1 st cover 40. The fixing screw 18 is inserted into the through hole of the 1 st cover 40 and screwed to the housing 10. Thereby, the 1 st cover 40 is fixed to the housing 10.

A plurality of positioning holes 49 are provided in the peripheral edge portion of the 1 st cover 40. In the present embodiment, the 1 st cover 40 is provided with two positioning holes 49. The positioning hole 49 penetrates the 1 st cover 40 in the plate thickness direction. In the assembly process of the inverter unit 1, a positioning pin provided in an assembly device (not shown) is inserted into the positioning hole 49. Thereby, the 1 st cover 40 and the assembly device are mutually positioned.

As shown in fig. 2, the 2 nd cover 50 has a plate shape. The 2 nd cover 50 is formed by press working. The 2 nd cover 50 includes a cover main body portion 51, a protruding portion 52, and a pressing portion 53.

The cover main body 51 has a plate shape in which the thickness direction coincides with the vertical direction. The thickness direction of the cover main body portion 51 coincides with the opening direction (vertical direction in the present embodiment) of the 2 nd housing chamber 12. The cover main body 51 covers the opening of the 2 nd storage chamber 12. That is, the 2 nd cover 50 covers the opening of the 2 nd housing chamber 12.

The cover main body portion 51 has an upper surface 51a and a lower surface 51 b. The lower surface 51b constitutes a part of the inner surface of the 2 nd accommodation chamber 12. The lower surface 51b is in contact with the upper end surface 10ca of the housing 10. The upper surface 51a is a surface facing the opposite side of the lower surface 51 b. The upper surface 51a is a surface facing the opening direction of the 2 nd accommodation chamber 12.

As shown in fig. 1, the cover main body 51 is fixed to the housing 10 at its peripheral edge by a plurality of fixing screws 18. A plurality of through holes (not shown) penetrating the hood main body 51 in the plate thickness direction are provided in the peripheral edge portion of the hood main body 51. The fixing screw 18 is inserted into the through hole of the cover main body 51 and screwed to the housing 10. Thereby, the 2 nd cover 50 is fixed to the housing 10. As shown in fig. 2, the 1 st cover 40 and the 2 nd cover 50 are fixed to one continuous surface (upper end surface 10ca) of the housing 10.

As shown in fig. 1, a plurality of positioning holes 59 are provided in the peripheral edge portion of the cover main body portion 51. In the present embodiment, two positioning holes 59 are provided in the cover main body portion 51. The positioning hole 59 penetrates the cover main body 51 in the plate thickness direction. In the assembly process of the inverter unit 1, a positioning pin provided in an assembly device (not shown) is inserted into the positioning hole 59. Thereby, the 2 nd cover 50 and the assembly device are positioned to each other.

When performing the connection step of connecting the connection portion 32a of the wiring portion 30 and the connection terminal 9b of the external power supply apparatus 9, the worker opens the opening of the 2 nd housing chamber 12. The inverter unit 1 of the present embodiment is provided with a 1 st cover 40 covering an opening of the 1 st housing chamber 11 and a 2 nd cover 50 covering an opening of the 2 nd housing chamber 12, respectively. According to the present embodiment, the worker can perform the connecting step in a state where the opening of the 1 st housing chamber 11 is closed. Therefore, the control board 21 and the inverter 25 in the 1 st housing chamber 11 can be prevented from being contaminated with dust and the like in the connection step.

As shown in fig. 3, the control board 21 has a switching element 71 and a connector 72. The power for the control unit is supplied to the connector 72 via the power supply wiring 73 for the control unit. The control portion power is supplied to the switching element 71.

Fig. 4 is a simple circuit diagram showing patterns of a ground system (GND system) of the switching element 71 and the connector 72 in the control substrate 21. As shown in fig. 4, the control substrate 21 has the 1 st pattern P1 and the 2 nd pattern P2. Pattern 1P 1 is connected to switching element 71, branches off, and is connected to connector 72. The 2 nd pattern is connected to the switching element 71, branched, and connected to the ground electrode (electrode) 74.

Coil elements 75 are provided in the 1 st pattern P1. The capacitor element 76 is provided in the 2 nd pattern P2. The control board 21 determines the impedance of the coil element 75 and the capacitance of the capacitor element 76 so that the current from the switching element 71 flows to the ground electrode 74 (2 nd pattern P2) more easily than the connector 72 (1 st pattern P1). Specifically, the control board 21 increases the impedance of the coil element 75 and increases the capacitance of the capacitor element 76, for example, so that the current from the switching element 71 flows more easily to the ground electrode 74 than to the connector 72.

Therefore, the common mode noise generated by the switching operation of the switching element 71 flows more easily to the ground electrode 74 than the connector 72. Therefore, in the inverter unit 1 of the present embodiment, it is possible to suppress the emission/conduction of the common mode noise generated by the switching operation to the outside through the power supply for the control unit.

As shown in fig. 5, the ground electrode 74 is provided on the lower surface of the control substrate 21. The ground electrode 74 is connected to the 3 rd bus bar 34 located above the resin capacitor cover 26 of the capacitor 23. Bus bar 3 34 is positioned on the upper surface of a support portion 61 provided on a top wall 26A (details will be described later) of cover 26.

The support portion 61 has a cylindrical shape extending in the vertical direction. The support portion 61 has a through hole 61a penetrating in the vertical direction. The metal cylindrical member 62 is positioned in the through hole 61 a. The cylindrical member 62 is fixed to the support portion 61. The cylindrical member 62 has a female screw portion extending in the vertical direction. The capacitor cover 26 and the cylindrical member 62 are integrated by, for example, two-color molding. The control board 21 is screwed to the female screw portion of the cylindrical member 62 from above by the male screw portion of the fixing member 27, and is fixed together with the 3 rd bus bar 34 in a state of being supported from below by the upper surface of the support portion 61. By screwing the fixing member 27 and the cylindrical member 62, the 3 rd bus bar 34 and the ground electrode 74 can be firmly connected.

Fig. 6 is a top view of the capacitor cover 26. As shown in fig. 2 and 6, the capacitor cover 26 has a top wall 26A, a side wall (1 st side wall) 26B, and a fixing wall 26C. The top wall 26A is located on the upper side and faces the control board 21. The side wall 26B extends downward from the edge of the ceiling wall 26A. The fixing wall 26C protrudes outward from the side wall 26B.

A plurality of support portions 61 (9 in fig. 6) are provided in the ceiling wall portion 26A. The control substrate 21 can be fixed in a state of being supported from below by the upper surface of the support portion 61 by screwing the fixing member 27 and the cylindrical member 62 in the same manner as described above without fixing the 3 rd bus bar 34 to the other support portions 61 except the support portion 61 to which the 3 rd bus bar 34 is fixed.

Fig. 7 is a partial perspective view of the capacitor cover 26 to which the 3 rd bus bar 34 is fixed. The capacitor cover 26 is provided with a step portion 26D at the lower end of the side wall 26B with respect to the location where the 3 rd bus bar 34 and the fixing wall 26C are located. The step portion 26D protrudes toward the + Y side toward the inner surface of the housing 10. A side wall (2 nd side wall) 26E extending downward is provided at an edge portion of the stepped portion 26. The fixed wall 26C extends from the lower end of the side wall 26E to the + Y side.

The 3 rd bus bar 34 has a 1 st portion 34a, a 2 nd portion 34b, a 3 rd portion 34c, a 4 th portion 34d, a 5 th portion 34e, a 6 th portion 34f, and a 7 th portion 34 g. The 1 st portion 34a is fixed between the support portion 61 and the control substrate 21. The 1 st portion 34a has an annular portion provided with a through hole penetrating in the Z direction. The 2 nd portion 34b extends downward from the + Y side end of the 1 st portion 34a toward the ceiling wall 26A.

The 3 rd portion 34c extends from the lower end of the 2 nd portion 34b along the top wall 26A in the Y direction. The 3 rd portion 34c has a widened portion 36 that is wider than the widths (lengths in the X direction) of the 2 nd and 4

th portions

34b, 34 d. The widened portion 36 has notches 37 on both sides in the width direction (X direction). The notch 37 has a V-shape that expands outward in the width direction in plan view.

The 4 th portion 34d extends downward from the + Y side end of the 3 rd portion 34c along the side wall 26B. The 5 th portion 34e extends from the lower end of the 4 th portion 34D along the step portion 26D in the Y direction. The 6 th portion 34f extends downward from the + Y side end of the 5 th portion 34E along the 2 nd side wall 26E. The 7 th portion 34g extends from the lower end of the 6 th portion 34f to the + Y side along the fixed wall 26C. The 7 th part 34g has: an annular portion 65 provided with a through hole penetrating in the Z direction; and a linear portion 66 extending from the annular portion 65 toward the-X side.

As shown in fig. 5, the distal end of the portion 1a on the-Y side is bent toward the-Z side from the annular portion. The front end of the 1 st portion 34a bent to the-Z side is inserted into a recessed portion 61b that opens on the upper surface of the support portion 61 and extends in the Z direction. The leading end of the 1 st part 34a is inserted into the recess 61b, whereby the 1 st part 34a can be prevented from being positionally displaced in the direction along the XY plane. When the fixing member 27 is screwed to the cylindrical member 62 by rotating about an axis parallel to the Z axis, the 1 st segment 34a can be prevented from rotating about an axis parallel to the Z axis by inserting the tip of the 1 st segment 34a into the recessed portion 61 b.

As shown in fig. 6 and 7, the top wall 26A has a pair of holding portions (1 st holding portion) 35a, 35b and a 1 st shaft portion 38.

The pair of holding

portions

35a and 35b protrude toward the + Z side. The pair of holding

portions

35a, 35b are provided on both sides of the 3 rd portion 34c in the width direction. The pair of holding

portions

35a and 35b are spaced apart from each other at a position of the widened portion 36 in the Y direction of the 3 rd portion 34 c. The pair of holding

portions

35a, 35b are positioned on both sides of the 3 rd portion 34c in the width direction, whereby the 3 rd portion 34c can be held in the X direction.

Of the pair of holding portions 35a and 35B, the holding portion 35B distant from the + X-side edge portion of the ceiling wall 26A extends to the side wall 26B, whereas the holding portion 35a close to the + X-side edge portion of the ceiling wall 26A extends to a position spaced apart from the side wall 26B in the Y direction. That is, the holding portion 35a is shorter than the holding portion 35 b.

Since the holding portion 35a extends to a position apart from the side wall 26B and is shorter than the holding portion 35B, the 4 th to 7 th portions 34d to 34g of the 3 rd bus bar 34 can be drawn out to the + X side from the gap between the + Y side end of the holding portion 35a and the side wall 26B.

The 1 st shaft portion 38 protrudes from the top wall 26A to the + Z side. The 1 st shaft portion 38 has a cylindrical shape. The 1 st shaft portion 38 protruding to the + Z side is press-fitted into the notch portion 37 of the 3 rd bus bar 34. The 1 st shaft portion 38 is press-fitted into the notch portion 37, whereby the 3 rd portion 34c of the 3 rd bus bar 34 can be prevented from coming off or being displaced.

As shown in fig. 6, the side wall 26E has a pair of holding portions (2 nd holding portion) 39. The holding portion 39 extends in the Z direction. The holding portions 39 are located on both sides in the width direction of the 4 th portion 34d in the 3 rd bus bar 34, and hold the 4 th portion 34d in the width direction. By holding the 4 th part 34d in the width direction by the pair of holding portions 39, the positional displacement of the 4 th part 34d in the X direction can be suppressed.

Fig. 8 is a sectional view of the periphery of the fixed wall 26C in the capacitor cover 26.

As shown in fig. 8, the fixed wall 26C is supported by the housing 10 from the lower side. The fixed wall 26C has a through hole 81 penetrating in the vertical direction. The through hole 81 is coaxial with the through hole of the 7 th portion 34g in the 3 rd bus bar 34. The housing 10 is provided with a female screw portion that is coaxial with the through hole 81 of the fixed wall 26C and opens upward. A metal cylindrical member 82 is positioned in the through hole 81. The cylindrical member 82 is fixed to the fixed wall 26C. The cylindrical member 82 has a through hole penetrating in the vertical direction. The fixing wall 26C and the cylindrical member 82 are integrated by, for example, two-color molding.

The 7 th part 34g of the 3 rd bus bar 34 and the fixing wall 26C are fixed to the housing 10 by a fixing member 28 made of metal having conductivity. The 7 th portion 34g is fixed to the housing 10 in a state of being in contact with the fixing member 28 and the cylindrical member 82. The fixing member 28 rotates about a central axis extending in the vertical direction, and the 7 th portion 34g and the fixing wall 26C are fixed to the housing 10 by screwing the male screw portions inserted into the through hole of the 7 th portion 34g and the through hole of the cylindrical member 82 to the female screw portion of the housing 10.

The 7 th portion 34g fixed to the case 10 by the fixing member 28 is electrically connected to the case 10 via the fixing member 28 and the cylindrical member 82. Therefore, the ground electrode 74 connected to the 1 st portion 34a in the 3 rd bus bar 34 and the housing 10 electrically connected to the 7 th portion 34g in the 3 rd bus bar 34 can be electrically connected through the 3 rd bus bar 34. By electrically connecting the grounded case 10 and the ground electrode 74, the common mode noise generated by the switching operation of the switching element 71 can flow to the case 10 through the 2 nd pattern P2, the ground electrode 74, and the 3 rd bus bar 34.

As shown in fig. 7, the leading end of the linear portion 66 of the 7 th portion 34g is bent to the-Z side as shown in fig. 8. The front end of the 7 th portion 34g bent to the-Z side is inserted into a recess 83 which is opened in the upper surface of the fixing wall 26C and extends in the Z direction. The leading end of the 7 th portion 34g is inserted into the recess 83, whereby the 7 th portion 34g can be prevented from being positionally displaced in the direction along the XY plane. When the fixing member 28 is screwed to the housing 10 by rotating about an axis parallel to the Z axis, the tip of the 7 th portion 34g is inserted into the recessed portion 83, whereby the 7 th portion 34g can be inhibited from rotating about an axis parallel to the Z axis.

The fixed wall 26C has a pair of 2 nd shaft portions 68. The 2 nd shaft portion 68 protrudes to the + Z side. The 2 nd shaft portion 68 has a cylindrical shape. The 2 nd shaft portion 68 holds the linear portion 66 on both sides of the linear portion 66 in the width direction. The 2 nd shaft portions 68 are disposed on both sides in the circumferential direction around the center axis line of rotation of the fixing member 28 when the screw fastening is performed with respect to the linear portion 66.

The linear portion 66 of the 7 th portion 34g has an arc-shaped notch 69 centered on the axial center of the 2 nd shaft portion 68. The linear portion 66 is held by the 2 nd shaft portion 68 at the notch portion 69.

Since the 2 nd shaft portions 68 are positioned on both sides in the circumferential direction around the center axis of rotation of the fixing member 28 and hold the linear portions 66, when the fixing member 28 is rotated and screwed to the housing 10, the linear portions 66 can be prevented from rotating around the center axis.

As described above, in the inverter unit 1 according to the present embodiment, even if common mode noise is generated by switching operation, the common mode noise is released to the case 10 through the 2 nd pattern P2, the ground electrode 74, and the 3 rd bus bar 34, and thus radiation/conduction to the outside by the power supply for the control unit through the connector 72 can be suppressed.

The preferred embodiments of the present invention have been described above with reference to the drawings, but the present invention is not limited to these examples. The shapes, combinations, and the like of the respective components shown in the above examples are merely examples, and various modifications can be made in accordance with design requirements and the like within a scope not departing from the gist of the present invention. The present invention is not limited to the embodiments. For example, in the above-described embodiment, the motor unit 3 is used as a power source of a vehicle, but the use of the motor unit is not limited to this.

In the above embodiment, the coil element 75 is provided in the 1 st pattern P1 and the capacitor element 76 is provided in the 2 nd pattern P2, but the present invention is not limited to this configuration, and other configurations are possible as long as the current from the switching element easily flows to the ground electrode 74.

Claims

1. An inverter unit for converting a direct current into an alternating current to supply the alternating current to a motor,

the inverter unit includes:

a grounded housing provided with a housing chamber opened to the outside;

a circuit board located in the receiving chamber; and

a bus bar electrically connecting the circuit board and the case,

the circuit board has:

a switching element;

a connector connected to an external power supply device;

an electrode connected to the bus bar; and

a ground pattern connected to the switching element, the connector, and the electrode,

the ground pattern is provided with a coil element having an impedance and a capacitor element having a capacitance, which make it easier for the current from the switching element to flow to the electrode than the connector.

2. The inverter unit according to claim 1,

a capacitor having a capacitor cover is located in the storage chamber closer to the bottom wall portion side of the case than the circuit board,

the capacitor cover has:

a top wall opposing the circuit board;

a 1 st side wall extending from an edge portion of the top wall toward the bottom wall portion side;

a step portion protruding from the bottom wall portion side end portion of the 1 st side wall toward the inner side surface of the case;

a 2 nd side wall extending from an edge of the stepped portion to the bottom wall portion side; and

a fixing wall that protrudes from the end portion of the 2 nd side wall on the bottom wall portion side toward the inner side surface of the case and is fixed to the case,

the top wall has:

a support portion that protrudes toward the circuit board and supports the circuit board from the bottom wall portion side; and

a pair of 1 st holding portions that hold the bus bar by protruding toward the circuit board on both sides in a width direction of the bus bar,

the 2 nd side wall has a pair of 2 nd holding portions that hold the bus bar by protruding toward an inner side surface of the housing on both sides in a width direction of the bus bar,

the bus bar includes:

a 1 st part fixed between the support part and the circuit board;

a 2 nd portion extending from an end of the 1 st portion toward the top wall;

a 3 rd portion extending from an end of the 2 nd portion along the top wall, held by the 1 st holding portion;

a 4 th portion extending from an end of the 3 rd portion along the 1 st sidewall;

a 5 th part extending from an end of the 4 th part along the stepped part;

a 6 th portion extending from an end of the 5 th portion along the 2 nd side wall, held by the 2 nd holding portion; and

and a 7 th portion extending from an end of the 6 th portion along the fixing wall, and fixed to the housing in an electrically connected state via a conductive fixing member that fixes the fixing wall to the housing.

3. The inverter unit according to claim 2,

said 3 rd portion having a wider width than a width of said 2 nd portion and a width of said 4 th portion,

the widened portion has notch portions on both sides in the width direction,

the capacitor cover has a 1 st shaft portion, and the 1 st shaft portion is inserted in a state of being pressed into the notch portion, respectively, by projecting from the top wall.

4. The inverter unit according to claim 2 or 3, wherein,

the 1 st holding portion of the pair of 1 st holding portions that is close to the edge portion of the top wall in the width direction is shorter than the other 1 st holding portion.

5. The inverter unit according to any one of claims 2 to 4, wherein,

the fixing member is provided so as to be rotatable about a center axis along a normal direction of the fixing wall,

the 7 th part has:

an annular portion having a through hole coaxial with the central axis; and

a linear portion extending linearly from the annular portion along the fixing wall,

the capacitor cover has a 2 nd shaft portion projecting from the fixed wall and holding the linear portion on both sides in the width direction,

the 2 nd shaft portions are located on both sides of the linear portion in the circumferential direction around the central axis.