Board unit and electronic device

Abstract

This board unit (30) comprises: a first board (31) and a second board (32); a terminal block (50) fixed to the first board (31); and a busbar (60) electrically connecting the second board (32) and the first board (31) through the terminal block (50). The busbar (60) comprises: a first fixed section (61) fixed to a conductive terminal section (51) provided in the terminal block (50); and a second fixed section (62) fixed to the second board (32). This arrangement allows two boards to be connected by a wiring member (busbar) having a large current capacity, and thus even a high-voltage and high-current circuit can be divided and mounted on a plurality of boards.　

Description

Substrate unit and electronic device

[0001] The present invention relates to a board unit in which a plurality of boards are electrically connected, and to an electronic device such as a motor control device that includes a board unit in which a plurality of boards are electrically connected.

[0002] Electronic devices such as inverter devices and servo amplifiers (motor control devices) that supply drive current to motors include a driver board on which an inverter circuit is mounted. Patent Document 1 describes an electronic device including this type of driver board.

[0003] Japanese Patent Application Laid-Open No. 2007-165423

[0004] Driver boards are equipped with large electronic components such as electrolytic capacitors and IGBT transistors. When the product specifications of an electronic device dictate the use of a large number of these electronic components, mounting all of the electronic components on a single board results in an increased board size. To address this issue, a multi-layered board structure has been proposed to accommodate the increased board size.

[0005] When a substrate is divided into multiple pieces, it is necessary to electrically connect the substrates to each other. Conventionally, a structure in which the substrates are connected by lead wires has been generally adopted. However, a structure in which the substrates are connected by lead wires has the problem of low assembly workability. Furthermore, in addition to the wiring for connecting the substrates to each other, it is also necessary to connect wiring for external output and wiring for power supply, so there is a demand for reducing the burden of wiring work and improving assembly workability.

[0006] Here, the board on which the inverter circuit is mounted has portions where wiring components with large current capacities are used, and bus bars are sometimes used as wiring members. Therefore, the inventors considered using bus bars as wiring members for connecting boards together. However, when using bus bars, dedicated jigs and parts for positioning the bus bars have been required in the past. Furthermore, because bus bars do not have an insulating coating, a structure that can provide insulation protection to ensure safety is required. This results in poor assembly workability and a complex structure.

[0007] In view of the above, an object of the present invention is to improve the assembly workability and simplify the structure of a board unit in which multiple boards are connected by wiring members, and an electronic device including such a board unit.

[0008] In order to solve the above problem, one aspect of the substrate unit of the present invention comprises a first substrate and a second substrate, a terminal block fixed to the first substrate, and a bus bar electrically connecting the first substrate and the second substrate via the terminal block, wherein the bus bar comprises a first fixing portion fixed to a conductive terminal portion provided on the terminal block, and a second fixing portion fixed to the second substrate.

[0009] According to the present invention, the first and second substrates are fixed to each other via a terminal block fixed to the first substrate and a bus bar. This allows the two substrates to be connected using wiring members (bus bars) with high current capacity, enabling even high-voltage, high-current circuits to be mounted separately on multiple substrates. Furthermore, since the terminal block is used to connect the wiring to the first substrate, the degree of freedom in bus bar placement is greater and the workability of connecting the bus bar is improved compared to a wiring structure in which the bus bar is directly connected to a hole drilled in the first substrate. Furthermore, since the wiring used for connecting not only between the substrates but also to the external device can be consolidated in the terminal block, the efficiency of wiring work is improved. Furthermore, when connecting the bus bar to the terminal block, positioning jigs and parts, dedicated parts for insulation protection, etc. can be omitted. This improves assembly workability and simplifies the configuration.

[0010] In one aspect of the circuit board unit of the present invention, the first substrate and the second substrate are stacked in a first direction, the terminal block includes a terminal block housing fixed to an edge of the first substrate, and the terminal block housing holds a plurality of the terminal portions aligned in a line in a second direction along the edge. The bus bar includes a linear portion extending in the first direction, the first fixing portion being provided at one end of the linear portion and fixed to the terminal portions from the outer periphery of the first substrate, and the second fixing portion being bent from the other end of the linear portion toward the outer periphery and fixed to the second substrate from the first substrate side. By dividing the substrate into two and multi-layering it in this way, the planar size of the circuit board unit can be reduced even when a circuit including many electronic components is mounted. Furthermore, due to this component shape and arrangement, the bus bar can be fixed and the wiring to the terminal block can all be connected from the same side (the outer periphery of the substrate). This improves assembly workability.

[0011] Alternatively, in one aspect of the board unit of the present invention, the first board may receive a power supply current via the terminal block and output a drive current to the outside via the terminal block. The drive current generation circuit that generates the drive current includes an inverter circuit, the first board is an inverter board on which the inverter circuit is mounted, and the second board is a power supply board that generates a direct current from the power supply current and supplies the direct current to the inverter circuit. In this way, by connecting the inverter board and the power supply board using a bus bar, the bus bar can be used as power wiring to separate the drive current generation circuit onto two boards. Therefore, even if the drive current generation circuit includes a large number of electronic components, the planar size of the board unit can be prevented from increasing.

[0012] Next, one aspect of the electronic device of the present invention includes the above-described board unit and a case that houses the board unit, the case including a cover member with an opening in which the terminal block is disposed, the bus bar including a connection portion that connects the first fixing portion and the second fixing portion, the connection portion fitting into a positioning recess provided on the inner surface of the cover member. This facilitates external input and output to and from the board unit. Furthermore, because the bus bar can be positioned by the cover member, there is no need to provide a separate bus bar positioning structure or a dedicated positioning jig. This simplifies the configuration and improves assembly workability. Furthermore, the cover member improves the insulation of the bus bar.

[0013] Alternatively, one aspect of the electronic device of the present invention includes the above-described board unit and a case that accommodates the board unit. The case includes a cover member having an opening in which the terminal block is disposed. The cover member has a first opening edge and a second opening edge that face each other in the first direction across the opening. The terminals are aligned in a line in the second direction along the first opening edge. The linear portion includes a connecting portion that connects the first fixing portion to the second fixing portion. The connecting portion extends inside the second opening edge in the first direction. The inside of the second opening edge includes a groove-shaped positioning recess extending in the first direction, and the connecting portion fits into the positioning recess. This configuration makes it easy to see the portion (connecting portion) that fits into the positioning recess when attaching the cover member, facilitating the fitting. This improves assembly workability. Furthermore, the cover member can improve the insulation of the bus bar and prevent short circuits.

[0014] Next, another aspect of the substrate unit of the present invention may include a busbar unit in which multiple busbars are integrated into a single resin part, the busbars having connecting portions connecting the first fixing portion and the second fixing portion, and the connecting portions having retained portions retained by the resin part. This configuration improves assembly workability because multiple busbars can be handled in a pre-positioned state. Furthermore, the configuration can be simplified because there is no need to prepare a positioning structure or dedicated jig for individually positioning the busbars. Furthermore, the spacing between the busbars can be ensured, improving insulation.

[0015] In this case, the terminal block may include a terminal block housing that holds the plurality of terminal portions arranged in a row, the terminal block housing including a partition wall that insulates adjacent terminal portions, the plurality of bus bars arranged in a direction in which the terminal portions are arranged, the first fixing portion of each bus bar being disposed between adjacent partition walls, the connection portion of each bus bar including an exposed portion that protrudes from the resin part and connects the held portion and the first fixing portion, and the width of the exposed portion in the direction in which the bus bars are arranged is narrower than the width of the first fixing portion in the direction in which the bus bars are arranged. In this way, an insulation distance can be ensured by widening the spacing between adjacent bus bars in areas where insulation is not possible with the partition wall.

[0016] Another aspect of the electronic device of the present invention includes the above-described board unit, a frame to which the board unit is fixed, and a case fixed to the frame and housing the board unit, wherein the resin part includes a positioning portion that fits into the frame to position the bus bar unit relative to the frame. This allows the bus bar unit to be positioned relative to the terminal block via the frame, thereby improving assembly workability. Furthermore, there is no need to provide a separate bus bar positioning structure or prepare a dedicated positioning jig. This simplifies the configuration.

[0017] In one aspect and another aspect of the electronic device of the present invention, the electronic device can be used as a motor control device that receives a power supply current via the terminal block and outputs a drive current to a motor via the terminal block. In this case, the drive current generation circuit that generates the drive current can include an inverter circuit, the first board can be an inverter board on which the inverter circuit is mounted, and the second board can be a power supply board that generates a direct current from the power supply current and supplies the direct current to the inverter circuit. In this way, by connecting the inverter board and the power supply board using a bus bar, the drive current generation circuit can be separated into two boards, with the bus bar serving as power wiring. Therefore, even if the drive current generation circuit includes a large number of electronic components, the planar size of the board unit can be prevented from increasing.

[0018] According to the present invention, the first and second substrates are fixed to each other via a terminal block fixed to the first substrate and a bus bar. This allows the two substrates to be connected using wiring members (bus bars) with high current capacity, enabling even high-voltage, high-current circuits to be mounted separately on multiple substrates. Furthermore, since the terminal block is used to connect the wiring to the first substrate, the degree of freedom in bus bar placement is greater and the workability of connecting the bus bar is improved compared to a wiring structure in which the bus bar is directly connected to a hole drilled in the first substrate. Furthermore, since the wiring used for connecting not only between the substrates but also to the external device can be consolidated in the terminal block, the efficiency of wiring work is improved. Furthermore, when connecting the bus bar to the terminal block, positioning jigs and parts, dedicated parts for insulation protection, etc. can be omitted. This improves assembly workability and simplifies the configuration.

[0019] 1 is a perspective view of a motor control device including a board unit according to a first embodiment; FIG. 2 is a perspective view of the motor control device with the opening / closing cover removed; FIG. 3 is an exploded perspective view of the motor control device as viewed from the front side (Z1 direction); FIG. 4 is an exploded perspective view of the motor control device as viewed from the rear side (Z2 direction); FIG. 5 is a front view of the board unit and frame according to the first embodiment; FIG. 6 is an exploded perspective view of the board unit and frame according to the first embodiment; FIG. 7 is an exploded perspective view of a first board, a second board, and a bus bar; FIG. 8 is a perspective view of the board unit and frame according to a second embodiment; FIG. 9 is a perspective view of a bus bar unit; FIG. 10 is a front view of a bus bar unit according to a modified example;

[0020] A board unit to which the present invention is applied and an electronic device including the board unit will be described below with reference to the drawings. One aspect of the electronic device described below is a motor control device 1. The motor control device 1 is a servo amplifier used to control a servo motor.

[0021] (Embodiment 1) Fig. 1 is a perspective view of a motor control device 1 including a board unit 30 of embodiment 1. Fig. 2 is a perspective view of the motor control device 1 with the terminal block 50 exposed. Fig. 3 is an exploded perspective view of the motor control device 1 as viewed from the front side (Z1 direction). Fig. 4 is an exploded perspective view of the motor control device 1 as viewed from the rear side (Z2 direction). Fig. 5 is a front view of the board unit 30 and frame 10 of embodiment 1. Fig. 6 is an exploded perspective view of the board unit 30 and frame 10 of embodiment 1. Fig. 7 is an exploded perspective view of a first board 31, a second board 32, and a bus bar 60.

[0022] In this specification, the three directions X, Y, and Z are perpendicular to each other. One side of the X direction is designated X1, and the other side of the X direction is designated X2. One side of the Y direction is designated Y1, and the other side of the Y direction is designated Y2. One side of the Z direction is designated Z1, and the other side is designated Z2. The X direction is the first direction. The X1 direction is one side of the first direction. The X2 direction is the other side of the first direction. The Y direction is the second direction.

[0023] The motor control device 1 is used in an installation position in which, for example, the X direction is the width direction of the motor control device 1, the Y direction is the up-down direction of the motor control device 1, and the Z direction is the front-to-back direction of the motor control device 1. Note that the motor control device 1 is not limited to being used in the above installation position. For example, the drawings in this specification show a state in which the motor control device 1 is installed with the X direction as the up-down direction. The Z1 direction is the front side of the motor control device 1, and the Z2 direction is the back side of the motor control device 1.

[0024] As shown in Figures 1 and 2, the motor control device 1 has an overall rectangular parallelepiped shape. As shown in Figure 3, the motor control device 1 includes a frame 10, a resin case 20 fixed to the frame 10, and a board unit 30 and a control board 40 (see Figures 3 and 5) fixed to the frame 10 and housed inside the case 20. As shown in Figure 6, the board unit 30 is a unit in which a first board 31 and a second board 32 are electrically connected.

[0025] The case 20 includes a first case 21 that covers the frame 10 from the X1 direction, a second case 22 that covers the frame 10 from the X2 direction, and a cover member 23 that covers the frame 10 from the Z1 direction. As shown in FIGS. 1 and 2 , the cover member 23 is the front panel of the motor control device 1. Hooks 27 that protrude in the Z2 direction are provided on the X1-direction edge and the X2-direction edge of the cover member 23. The cover member 23 is fixed to the first case 21 and the second case 22 by engaging the hooks 27 with protrusions provided on the Z1-direction edges of the first case 21 and the second case 22.

[0026] A connector unit 24 is provided in the X1 direction portion of the cover member 23. Connector components (not shown) mounted on the Z1 direction edge of the control board 40 (see FIG. 3) are placed in multiple holes provided in the connector unit 24. In addition, an opening / closing lid 25 (see FIG. 1) is provided in the X2 direction portion of the cover member 23. The opening / closing lid 25 opens and closes an opening 26 provided in the cover member 23. When the opening / closing lid 25 is opened, an input / output terminal block 50 is exposed on the front surface of the motor control device 1, as shown in FIG. 2. As shown in FIG. 3, the terminal block 50 is located at the Z1 direction end of the board unit 30.

[0027] As shown in FIG. 6 , the frame 10 includes a plate-shaped frame body 11 extending along the YZ plane and a back panel 12 attached to the rear end (the end in the Z2 direction) of the frame body 11. The frame 10 is made of a metal with good thermal conductivity, such as aluminum. Plate-shaped heat dissipation fins 13 extending in the X1 direction are integrally formed with the frame body 11. A board unit 30 fixed to the frame body 11 is equipped with an inverter circuit that generates a large amount of heat, and the heat generated by the inverter circuit is transferred from the frame body 11 to the heat dissipation fins 13. A regenerative resistor (not shown) connected to the inverter circuit is also fixed to the heat dissipation fins 13. The regenerative resistor converts regenerative energy generated during deceleration of a servo motor connected to the motor control device 1 into heat. A cooling fan (not shown) is located inside the case 20 to blow air onto the heat dissipation fins 13.

[0028] The frame main body 11 includes a boss portion for fixing the first board 31 of the board unit 30 and a boss portion for fixing the second board 32. The frame main body 11 includes a first side plate 14 extending in the X direction along the Y1-direction end and a second side plate 15 extending in the X direction along the Y2-direction end. As shown in FIGS. 1 and 2 , the first side plate 14 is provided with a protrusion that engages with a hook 28 provided on the first case 21 and a hook 29 provided on the second case 22. The second side plate 15 is also provided with a protrusion that forms a similar hook mechanism. Therefore, the first case 21 and the second case 22 are fixed to the frame 10 by the hook mechanism.

[0029] 3, the control board 40 is disposed along the inner surface of the first case 21. The control board 40 is fixed to the frame 10 by being screwed onto a support (not shown) extending from the frame main body 11 in the X1 direction. A control circuit for supplying a drive signal to the board unit 30 is mounted on the control board 40.

[0030] The control circuit includes electronic elements such as an MCU (Micro Controller Unit) and a gate drive IC. External control commands are input to the MCU via the connector 24. The MCU also receives an encoder signal via the connector 24 from an encoder mounted on the servo motor, as well as current detection signals for two of the three-phase motor drive currents generated in the board unit 30. The MCU supplies a PWM signal to the gate drive IC based on the encoder signal and the current detection signal. The gate drive IC supplies a gate drive signal to the inverter circuit of the board unit 30 based on the PWM signal.

[0031] (Board Unit) A drive current generation circuit that generates a three-phase motor drive current is mounted on the board unit 30. The drive current generation circuit includes a rectifier circuit that rectifies the power supply current supplied from the AC power supply, an electrolytic capacitor (main circuit capacitor) connected to the rectifier circuit, and an inverter circuit that generates a three-phase motor drive current based on the DC current supplied from the main circuit capacitor.

[0032] The board unit 30 has a drive current generation circuit mounted on two boards, a first board 31 and a second board 32. The first board 31 is an inverter board. Specifically, the first electronic element E1 (see FIG. 6 ) mounted on the first board 31 includes, for example, an IGBT transistor constituting an inverter circuit. In this case, the IGBT transistors on the first board 31 are switched based on gate drive signals supplied from the control board 40, generating U-phase, V-phase, and W-phase motor drive currents. Alternatively, an IPM (intelligent power module) module, which modularizes an inverter circuit, may be used as the first electronic element E1. The second board 32 is a power supply board that generates DC current from a power supply current and supplies it to the inverter circuit on the first board 31. The second electronic element E2 mounted on the second board 32 includes an electrolytic capacitor (main circuit capacitor) (see FIG. 6 ).

[0033] As shown in FIG. 3 , the board unit 30 is a unit in which a first board 31 disposed inside the second case 22 and a second board 32 disposed parallel to the first board 31 in the X1 direction of the first board 31 are electrically connected via a terminal block 50 and bus bars 60. The bus bars 60 are wiring members made of a conductive metal. The bus bars 60 are wiring members with a large current capacity and are used as power wiring. In this embodiment, five bus bars 60 are connected to the terminal block 50 and the second board 32.

[0034] The terminal block 50 is disposed on the first board 31, which is an inverter board. Power supply current from an external AC power supply is input to three of the multiple terminals 51 provided on the terminal block 50 and supplied to the second board 32 via the bus bar 60. Direct current is supplied from the second board 32 to the first board 31 via the bus bar 60. A three-phase motor drive current generated by the inverter circuit on the first board 31 is output to the servo motor from the three terminals 51 on the terminal block 50 to which the bus bar 60 is not connected. In this embodiment, since the terminal block 50 is provided on the first board 31, the motor drive current generated on the first board 31 is output to the servo motor directly from the terminal block 50 on the first board 31 without passing through another board.

[0035] As shown in Figures 6 and 7, the terminal block 50 includes a resin terminal block housing 52 that is fixed to the edge 33 of the first substrate 31 in the Z1 direction. The terminal block housing 52 extends linearly in the Y direction along the edge 33. The terminal block housing 52 holds a plurality of terminals 51 that are aligned in the Y direction. Each terminal 51 is a conductive metal part that has a screw hole that opens in the Z1 direction. The terminal block housing 52 includes a plurality of partition walls 53 that protrude in the Z1 direction. The terminals 51 and the partition walls 53 are aligned alternately in a row in the Y direction along the edge 33 of the first substrate 31.

[0036] As shown in FIG. 7 , the bus bar 60 is a plate-like metal member bent into an L-shape. The bus bar 60 includes a first fixing portion 61 fixed to the terminal portion 51, a second fixing portion 62 fixed to the second substrate 32, and a connecting portion 63 connecting the first fixing portion 61 and the second fixing portion. The first fixing portion 61 and the second fixing portion 62 each have a through-hole for fixing. The first fixing portion 61 and the connecting portion 63 form a linear portion 64 extending linearly in the X direction. The first fixing portion 61 is provided at the end of the linear portion 64 in the X2 direction. The second fixing portion 62 bends at a substantially right angle from the end of the linear portion 64 in the X1 direction and extends in the Z1 direction. The second fixing portion 62 has the same width as the connecting portion 63 and the first fixing portion 61.

[0037] As shown in FIGS. 6 and 7 , when connecting the bus bar 60 to the terminal portion 51, the first fixing portion 61 is inserted between adjacent partition walls 53 and fixed to the terminal portion 51 from the Z1 direction with conductive screws 54. The second substrate 32 has holes for fixing the bus bar. The holes for fixing the bus bar are aligned in the Y direction along the edge portion 34 of the second substrate 32 in the Z1 direction. When connecting the bus bar 60 to the second substrate 32, the second fixing portion 62 is fixed to the second substrate 32 from the X direction. At this time, the hole in the second fixing portion 62 is aligned with the hole in the second substrate 32 and fixed with the conductive screws 54. This electrically connects the bus bar 60 to the circuit pattern on the second substrate 32.

[0038] (Busbar Positioning Structure) As shown in Figures 3 and 4, the opening 26 of the cover member 23 is rectangular with the longitudinal direction in the Y direction. The cover member 23 has a first opening edge 261 and a second opening edge 262 that face each other in the X direction across the opening 26. The first opening edge 261 is located in the X2 direction of the opening 26, and the second opening edge 262 is located in the X1 direction of the opening 26. As shown in Figure 2, in the terminal block 50, the partition walls 53 aligned in the Y direction protrude in the Z direction from the opening 26. The terminal portions 51 are aligned in a row along the first opening edge 261 of the opening 26.

[0039] When assembling the motor control device 1, the board unit 30 is fixed to the frame 10. Then, the first case 21 and the second case 22 are fixed to the frame 10. As a result, as shown in FIG. 3 , the terminal block 50 and the bus bar 60 are positioned at the end of the board unit 30 in the Z1 direction. Thereafter, the cover member 23 is placed over the board unit 30 from the Z1 direction and fixed to the first case 21 and the second case 22 by the hook mechanism described above, and the terminal block 50 is positioned in the opening 26 (see FIG. 2 ). At this time, the bus bar 60 is fitted into the positioning recess 230 provided on the inner surface of the cover member 23.

[0040] As shown in Fig. 4, the positioning recesses 230 are provided on the inside of the second opening edge 262. The positioning recesses 230 are grooves extending in the X direction. The positioning recesses 230 are aligned in the Y direction along the second opening edge 262. The positioning recesses 230 are provided in five locations in accordance with the arrangement of the bus bars 60. As shown in the partially enlarged view of Fig. 4, the connection portions 63 of the bus bars 60 extend in the X direction inside the second opening edge 262 (Z2 direction) and fit into the positioning recesses 230.

[0041] (Operation and Effect of First Embodiment) As described above, the board unit 30 of the first embodiment includes the first board 31, the second board 32, the terminal block 50 fixed to the first board 31, and the bus bar 60 that electrically connects the first board 31 and the second board 32 via the terminal block 50. The bus bar 60 includes a first fixing portion 61 fixed to the conductive terminal portion 51 provided on the terminal block 50, and a second fixing portion 62 fixed to the second board 32.

[0042] As described above, in the board unit 30 of the first embodiment, the first board 31 and the second board 32 are connected by the bus bar 60, allowing various circuits to be mounted separately on the first board 31 and the second board 32. Furthermore, since the bus bar 60 is used as the wiring member instead of a lead wire, the wiring member is easily positioned, facilitating the work of connecting the wiring. Furthermore, since the terminal block 50 is fixed to the first board 31 and the bus bar 60 is connected to the terminal block 50, the degree of freedom in the placement of the bus bar 60 is greater and the workability of connecting the bus bar 60 is improved compared to a wiring structure in which a hole is drilled in the first board 31 and the bus bar 60 is directly connected. Furthermore, since the bus bar 60 is easily positioned, positioning jigs and parts, dedicated parts for insulation protection, etc. can be omitted. This improves assembly workability and simplifies the configuration. Furthermore, not only the bus bar 60 but also other input / output wiring can be consolidated on the terminal block 50. This saves space on the board and improves the efficiency of wiring work.

[0043] In the board unit 30 of the first embodiment, the first board 31 and the second board 32 are stacked in the X direction (first direction). By dividing the board into two boards and stacking them in this manner, the planar size of the board unit 30 can be reduced even when a circuit including many electronic components is mounted. The terminal block 50 also includes a terminal block housing 52 fixed to the edge portion 33 of the first board 31. The terminal block housing 52 holds a plurality of terminal portions 51 aligned in a row in the Y direction (second direction) along the edge portion 33. The bus bar 60 includes a linear portion 64 extending in the X direction (first direction). The first fixing portion 61 is provided at the end of the linear portion 64 in the X1 direction and is fixed to the terminal portions 51 from the Z1 direction (i.e., from the outer periphery of the first board 31). The second fixing portion 62 is bent in the Z1 direction from the X1-direction end of the straight portion 64 and is fixed to the second board 32 from the X2 direction (i.e., from the side of the first board 31). With this configuration, the connection of the bus bar 60 and the connection of other wiring to the terminal block 50 can all be performed from the outer periphery side (Z1 direction) of the first board 31. This improves assembly workability.

[0044] The motor control device 1 of the first embodiment receives a power supply current via a terminal block 50 on the board unit 30 and outputs a drive current to the servo motor via the terminal block 50. The drive current generation circuit that generates the drive current includes an inverter circuit, and the first board 31 is an inverter board on which the inverter circuit is mounted. The second board 32 is a power supply board that generates a DC current from the power supply current and supplies it to the inverter circuit. By connecting the inverter board (first board 31) and the power supply board (second board 32) using a bus bar 60, the drive current generation circuit can be divided into two boards, with the bus bar 60 serving as power wiring. Therefore, even if the drive current generation circuit includes a large number of electronic components, the planar size of the board unit 30 can be kept small. Furthermore, because the terminal block 50 is provided on the inverter board (first board 31), the motor drive current generated on the first board 31 can be output directly to the servo motor from the terminal block 50 on the first board 31 without passing through another board. Therefore, there is no need to provide unnecessary relay wiring, which saves space on the board and simplifies the wiring structure.

[0045] The motor control device 1 of the first embodiment includes a board unit 30 and a case 20 that houses the board unit 30. The case 20 includes a cover member 23 that has an opening 26 in which a terminal block 50 is disposed. The bus bar 60 includes a connection portion 63 that connects a first fixing portion 61 and a second fixing portion 62. The connection portion 63 fits into a positioning recess 230 provided on the inner surface of the cover member 23. This allows wiring for connection to the external device to be directly connected to the terminal block 50 of the board unit 30. Therefore, input from the external device and output to the external device can be performed without unnecessary relay wiring. This simplifies the wiring structure. Furthermore, because the bus bar 60 can be positioned using the cover member 23, there is no need to provide a separate positioning structure for the bus bar 60, and there is no need to prepare a dedicated jig for positioning the bus bar 60. This simplifies the configuration and improves assembly workability. Furthermore, the cover member 23 can cover the exposed portion of the bus bar 60 (i.e., the connection portion 63), thereby improving insulation and preventing short circuits of the bus bar 60.

[0046] More specifically, in the motor control device 1 of the first embodiment, the cover member 23 includes a first opening edge 261 and a second opening edge 262 that face each other in the X direction (first direction) across the opening 26. The terminals 51 are aligned in a row in the Y direction (second direction) along the first opening edge 261. The connection portions 63 of the bus bars 60 extend in the X direction (first direction) inside the second opening edge 262. A groove-shaped positioning recess 230 extending in the X direction (first direction) is provided inside the second opening edge 262, and the connection portions 63 fit into the positioning recess 230. In this manner, when attaching the cover member 23, the connection portions 63 extending in the X direction between the first board 31 and the second board 32 are exposed on the cover member 23 side, making the fitting portions easily visible and easy to fit. This improves assembly workability.

[0047] (Embodiment 2) Hereinafter, the same components as those in embodiment 1 will be assigned the same reference numerals and their descriptions will be omitted, and only the differences will be described. Fig. 8 is a perspective view of a board unit 30A and a frame 10 in embodiment 2. Fig. 9 is a perspective view of a bus bar unit 70. A motor control device (not shown) in embodiment 2 includes a frame 10, a board unit 30A fixed to the frame 10, and a case (not shown) fixed to the frame 10 and accommodating the board unit 30A. As in embodiment 1, the case in embodiment 2 includes a cover member (not shown) that covers the frame 10 and the board unit 30A from the Z1 direction, but the inner surface of the cover member does not have a shape for fitting and positioning the bus bar 60 of the board unit 30A.

[0048] 8 and 9 , the board unit 30A of the second embodiment includes a first board 31, a second board 32, a terminal block 50 fixed to the first board 31, and a bus bar unit 70. As in the first embodiment, the terminal block 50 is disposed in an opening in a cover member (not shown) of the motor control device. The bus bar unit 70 includes a plurality of bus bars 60 and a resin part 65. The bus bars 60 are integrated with the resin part 65 by insert molding.

[0049] The resin part 65 is a resin block that is long in the Y direction. As shown in Fig. 8 , the resin part 65 includes a busbar holding portion 651 that extends linearly in the Y direction in the X1 direction of the terminal block 50, and a pair of protrusions 652 that protrude in the X2 direction from both Y direction ends of the busbar holding portion 651. The multiple busbars 60 are held by the busbar holding portion 651 in an arrangement that corresponds to the arrangement of the mating terminal portions 51 of the terminal block 50. As shown in Fig. 8 , the terminal block housing 52 is fitted between the pair of protrusions 652. As a result, the multiple busbars 60 are each positioned in the Y direction relative to the mating terminal portions 51.

[0050] 9 , each bus bar 60 includes a first fixing portion 61 and a connecting portion 63 extending in the X direction, and a second fixing portion 62 that bends at a substantially right angle from the X1-direction end of the connecting portion 63 and extends in the Z1 direction. The connecting portion 63 includes a held portion 66 that is held by a bus bar holding portion 651 of a resin part 65. The X1-direction portion and the X2-direction portion of the held portion 66 of the connecting portion 63 protrude from the bus bar holding portion 651 in the X1 and X2 directions and are connected to the second fixing portion 62 and the first fixing portion 61.

[0051] 9 , the resin part 65 has positioning portions 650 that fit into the Z1-direction ends of the frame main body 11. The positioning portions 650 are recesses provided in a pair of protrusions 652 of the resin part 65. More specifically, the positioning portions 650 are grooves that extend in the Y direction and are recessed in the Z1 direction. By fitting the Z1-direction ends of the frame main body 11 into the positioning portions 650, the resin part 65 is positioned in the X and Z directions. As a result, the multiple bus bars 60 are each positioned in the X and Z directions with respect to the terminal portions 51 of their connection partners.

[0052] (Effects of Second Embodiment) As described above, the board unit 30 of the second embodiment includes a busbar unit 70 in which multiple busbars 60 are integrated into a single resin part 65. The busbars 60 include connecting portions 63 that connect the first fixing portions 61 and the second fixing portions 62. The connecting portions 63 include held portions 66 that are held by the resin part 65. This allows the multiple busbars 60 to be handled in a state where they are pre-positioned to correspond to the positions of the terminal portions 51 of the mating connections. This improves assembly workability. Furthermore, there is no need to individually position the busbars 60, and therefore no need to prepare a positioning structure or dedicated jig for this purpose. This simplifies the configuration. Furthermore, there is little risk of the busbars 60 coming into contact with each other, reducing the risk of the busbars 60 shorting out.

[0053] As described above, a motor control device (not shown) including the board unit 30A of the second embodiment includes a frame 10 to which the board unit 30A is fixed and a case (not shown) fixed to the frame 10 and housing the board unit 30A. The resin part 65 includes a positioning portion 650 that fits into the frame 10. Specifically, the positioning portion 650 includes a groove-shaped recess that fits into the frame. Therefore, the resin part 65 can be positioned relative to the frame 10, and the bus bars 60 held by the resin part 65 can be positioned relative to the terminal block 50 in the X and Z directions via the frame 10. In addition, the resin part 65 includes a pair of protrusions 652 that can position the terminal block housing 52 in the Y direction. Therefore, the first fixing portion 61 can be positioned relative to the terminal block 51 in the X, Y, and Z directions, improving assembly workability. Furthermore, there is no need to provide a separate positioning structure for individually positioning each of the multiple bus bars 60, and there is no need to prepare a dedicated positioning jig. This simplifies the configuration.

[0054] Similar to the first embodiment, the board unit 30A of the second embodiment is used in a motor control device that receives a power supply current via the terminal block 50 of the board unit 30A and outputs a drive current to a servo motor via the terminal block 50. Therefore, similar to the first embodiment, even if a large number of electronic components are included in the drive current generating circuit, the planar size of the board unit 30A can be prevented from increasing. Furthermore, since the terminal block 50 is provided on the inverter board (first board 31), the motor drive current generated on the first board 31 can be output directly to the servo motor from the terminal block 50 of the first board 31 without passing through another board. Therefore, there is no need to provide unnecessary relay wiring, which saves board space and simplifies the wiring structure.

[0055] (Modification of Second Embodiment) Fig. 10 is a front view of a busbar unit 70A according to a modification. The busbar unit 70A includes a plurality of busbars 60A aligned in a line in the Y direction and a resin part 65 integrated with the busbars 60A by insert molding. The shape of the resin part 65 is the same as in the second embodiment. The terminal block 50 to which each busbar 60A is connected has the same configuration as in the first and second embodiments, and includes a terminal block housing 52 that holds a plurality of terminal portions 51 aligned in a line in the Y direction. The terminal block housing 52 includes a partition wall 53 that insulates adjacent terminal portions 51.

[0056] The busbar 60A of the modified example differs from the busbar 60 of the above-described embodiments in the shape of a connecting portion 63A connecting the first fixing portion 61 and the second fixing portion 62. The connecting portion 63A includes a held portion 66 held by a resin part 65 and an exposed portion 67 protruding from the resin part 65 in the X2 direction and connecting the held portion 66 and the first fixing portion 61. The first fixing portion 61 is disposed between adjacent partition walls 53, and insulation is ensured by the partition walls 53. On the other hand, no partition wall 53 is disposed between adjacent exposed portions 67. However, the width of the exposed portion 67 in the Y direction (i.e., the width in the arrangement direction in which the terminal portions 51 and the busbar 60A are arranged) is smaller than the width of the first fixing portion 61 in the Y direction. Therefore, the busbar unit 70A of the modified example has a wide gap between adjacent exposed portions 67, ensuring an insulation distance. Therefore, in the areas where insulation cannot be achieved by the partition wall 53 of the terminal block 50, an insulation distance can be ensured between adjacent bus bars 60.

[0057] (Other embodiments) (1) In each of the above embodiments, the present invention is applied to a motor control device 1 that receives a power supply current via a terminal block 50 and outputs a drive current to a motor via the terminal block 50. However, the present invention can be applied to various electronic devices other than the motor control device 1.

[0058] (2) In the above embodiments, the present invention is applied to the board unit 30 in which the terminal block 50 of the inverter board and the power supply board are connected via the bus bar 60. However, the present invention can also be applied to a board unit in which boards for other purposes are connected via the terminal block 50 and the bus bar 60. That is, the first board 31 does not have to be an inverter board. Also, the second board 32 does not have to be a power supply board.

[0059] (3) In the above embodiments, the bus bar 60 is L-shaped. However, the shape of the bus bar 60 is not limited to the L-shape. For example, the terminal block 50 may be configured to fix the bus bar 60 from a direction different from the Z1 direction. In this case, the first fixing portion 61 may be bent to match the fixing direction with respect to the terminal portion 51.

Claims

1. A board unit comprising: a first board and a second board; a terminal block fixed to the first board; and a bus bar electrically connecting the first board and the second board via the terminal block, wherein the bus bar has a first fixing portion fixed to a conductive terminal portion provided on the terminal block, and a second fixing portion fixed to the second board.

2. The board unit described in claim 1, characterized in that the first board and the second board are stacked in a first direction, the terminal block has a terminal block housing fixed to an edge of the first board, and the terminal block housing holds a plurality of the terminal portions arranged in a row in a second direction along the edge, the bus bar has a straight portion extending in the first direction, the first fixing portion is provided at one end of the straight portion and is fixed to the terminal portions from the outer periphery side of the first board, and the second fixing portion is bent from the other end of the straight portion toward the outer periphery and is fixed to the second board from the side of the first board.

3. The board unit described in claim 1, characterized in that the first board receives a power supply current via the terminal block and outputs a drive current to the outside via the terminal block, a drive current generating circuit that generates the drive current includes an inverter circuit, the first board is an inverter board on which the inverter circuit is mounted, and the second board is a power supply board that generates a direct current from the power supply current and supplies it to the inverter circuit.

4. An electronic device comprising: a board unit as described in claim 1; and a case for housing the board unit, wherein the case has a cover member having an opening in which the terminal block is disposed, and the bus bar has a connection portion connecting the first fixed portion and the second fixed portion, the connection portion fitting into a positioning recess provided on the inner surface of the cover member.

5. An electronic device comprising: a board unit as described in claim 2; and a case for accommodating the board unit, wherein the case has a cover member with an opening in which the terminal block is disposed, the cover member has a first opening edge and a second opening edge facing each other in the first direction across the opening, the multiple terminal portions are aligned in a row in a second direction along the first opening edge, the straight portion has a connection portion connecting the first fixed portion and the second fixed portion, the connection portion extending in the first direction along the inside of the second opening edge, and a groove-shaped positioning recess extending in the first direction is provided on the inside of the second opening edge, and the connection portion fits into the positioning recess.

6. The electronic device described in claim 4, which is used as a motor control device that receives a power supply current via the terminal block and outputs a drive current to a motor via the terminal block, wherein a drive current generating circuit that generates the drive current includes an inverter circuit, the first board is an inverter board on which the inverter circuit is mounted, and the second board is a power supply board that generates a DC current from the power supply current and supplies it to the inverter circuit.

7. A board unit as described in claim 1, comprising a busbar unit in which a plurality of the busbars are integrated into a single resin part, the busbar having a connection portion that connects the first fixed portion and the second fixed portion, the connection portion having a held portion that is held by the resin part.

8. The board unit described in claim 7, characterized in that the terminal block comprises a terminal block housing that holds a plurality of the terminal portions arranged in a row, the terminal block housing comprising a partition wall that insulates adjacent terminal portions, the plurality of bus bars are arranged in the arrangement direction of the terminal portions, the first fixed portion of each bus bar is disposed between adjacent partition walls, the connection portion of each bus bar comprises an exposed portion that protrudes from the resin part and connects the held portion and the first fixed portion, and the width of the exposed portion in the arrangement direction is narrower than the width of the first fixed portion in the arrangement direction.

9. An electronic device comprising: a board unit as described in claim 7; a frame to which the board unit is fixed; and a case fixed to the frame and housing the board unit, wherein the resin part is provided with a positioning portion that positions the busbar unit relative to the frame by fitting into the frame.

10. The electronic device described in claim 9, which is used as a motor control device that receives a power supply current via the terminal block and outputs a drive current to a motor via the terminal block, wherein a drive current generating circuit that generates the drive current includes an inverter circuit, the first board is an inverter board on which the inverter circuit is mounted, and the second board is a power supply board that generates a DC current from the power supply current and supplies it to the inverter circuit.

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