Electronic control device, drive device, and steering control device

Abstract

In one embodiment, an electronic control device according to the present disclosure is provided with a wiring board on which at least one switching element is mounted in a path for supplying power from a power source to a motor. The wiring board has, on the surface thereof, a land pattern to which electrodes of the switching element are joined by soldering, the electrode including a back electrode and a lead electrode integrated with each other. In the land pattern, a first portion to which the back electrode is soldered and a second portion to which the lead electrode is soldered are separated by a non-conductive resist.

Description

Electronic control device, drive device and steering control device

[0001] The present disclosure relates to an electronic control device, a drive device, and a steering control device.

[0002] An electronic control device used in an electric power steering device or the like includes, for example, a wiring board having electronic components that constitute an inverter circuit. The electronic components have, for example, electrodes in which a lead electrode and a back electrode are integrally formed. The lead electrode and the back electrode are joined by soldering to a land pattern formed on the surface of the wiring board. When soldering the lead electrode and the back electrode to the land pattern, there is a possibility that the solder in the lead electrode will be insufficient, resulting in a low joint strength. In response to this, Patent Document 1 discloses a technology for ensuring the amount of solder in the lead by preventing the wetting and lifting of molten solder.

[0003] Japanese Unexamined Patent Publication No. 19756 / 1986

[0004] The technology disclosed in Patent Document 1 has a special structure and is not very versatile, and there are cases where it is not possible to resolve the lack of solder in the lead portion.

[0005] In view of the above circumstances, the present disclosure aims to provide an electronic control device, a drive device, and a steering control device that can ensure a sufficient amount of solder when soldering lead electrodes of an electronic component to a wiring board.

[0006] One aspect of the electronic control device according to the present disclosure includes a wiring board carrying at least one switching element in a path for supplying power from a power source to a motor, the wiring board having a land pattern on the surface of the wiring board to which the electrode of the switching element, which has an electrode in which a back electrode and a lead electrode are integrated, is joined by soldering, and the land pattern is separated by a non-conductive resist into a first portion to which the back electrode is soldered and a second portion to which the lead electrode is soldered.

[0007] One aspect of the electronic control device according to the present disclosure includes a wiring board carrying at least one switching element in a path for supplying power from a power source to a motor, the wiring board having a land pattern on the surface of the wiring board to which the electrode of the switching element, which has an electrode in which a back electrode and a lead electrode are integrated, is soldered, and the land pattern is formed so that a first portion to which the back electrode is soldered and a second portion to which the lead electrode is soldered are separated.

[0008] One aspect of an electronic control device according to the present disclosure includes a wiring board carrying at least one switching element in a path for supplying power from a power source to a motor, the wiring board having a land pattern on its surface to which the electrode of the switching element, which has an electrode in which a back electrode and a lead electrode are integrated, is soldered, the land pattern having a first portion to which the back electrode is soldered, a second portion to which the lead electrode is soldered, and a bridging portion that is narrower than the second portion and connects the first portion and the second portion, the bridging portion being defined and formed by a non-conductive resist.

[0009] One aspect of an electronic control device according to the present disclosure includes a wiring board carrying at least one switching element in a path for supplying power from a power source to a motor, the wiring board having a land pattern on its surface to which the electrode of the switching element, which has an electrode in which a back electrode and a lead electrode are integrated, is soldered, the land pattern having a first portion to which the back electrode is soldered, a second portion to which the lead electrode is soldered, and a bridging portion that is narrower than the second portion and connects the first portion and the second portion.

[0010] One aspect of a drive device according to the present disclosure includes the electronic control device and a motor controlled by the electronic control device.

[0011] One aspect of a steering control device according to the present disclosure includes the drive device.

[0012] According to the present disclosure, a sufficient amount of solder can be secured when soldering lead electrodes of an electronic component to a wiring board.

[0013] Fig. 1 is a cross-sectional view of an electric power steering device according to embodiment 1. Fig. 2 is a circuit diagram of the electric power steering device according to embodiment 1. Fig. 3 is a plan view of a wiring board of the electric power steering device according to embodiment 1. Fig. 4 is a plan view of a switching element in the electric power steering device according to embodiment 1. Fig. 5 is a plan view of a land pattern in the electric power steering device according to embodiment 1. Fig. 6 is a plan view of a land pattern in the electric power steering device according to embodiment 2. Fig. 7 is a plan view of a land pattern in the electric power steering device according to embodiment 3. Fig. 8 is a plan view of a land pattern in the electric power steering device according to embodiment 4.

[0014] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. Note that the scope of the present disclosure is not limited to the following embodiments and can be modified as desired within the scope of the technical concept of the present disclosure.

[0015] Embodiment 1 Fig. 1 is a cross-sectional view of an electric power steering device 100 according to embodiment 1. Fig. 2 is a circuit diagram of the electric power steering device 100.

[0016] As shown in FIG. 1 , the electric power steering device 100 includes a motor 30 and a control unit 10 that controls the motor 30 .

[0017] The electric power steering device 100 is an example of a "drive device." The electric power steering device 100 assists the driver in steering the vehicle as a drive device. The electric power steering device 100 is included in a steering control device 1000. The steering control device 1000 includes, for example, a steering wheel for the vehicle, a mechanical steering mechanism, etc. in addition to the electric power steering device 100.

[0018] The motor 30 includes a motor housing 31, a rotating shaft 32, and a motor body 33. The motor 30 is, for example, a three-phase brushless motor or a permanent magnet synchronous motor.

[0019] The motor housing 31 includes a cylindrical portion 31a and a bottom portion 31b. The motor housing 31 is made of, for example, metal (e.g., aluminum). A through-hole 31c is formed in the center of the bottom portion 31b, through which the rotary shaft 32 passes. A first bearing 41 is attached to the bottom portion 31b.

[0020] The motor body 33 is housed in the cylindrical portion 31a. The motor body 33 includes a rotor 36 and a stator 37. The rotor 36 is provided around the rotating shaft 32. A plurality of permanent magnets are provided on the outer peripheral surface of the rotor 36. The stator 37 is provided on the outer peripheral side of the rotor 36. The stator 37 includes the windings 30a.

[0021] A motor frame 40 is provided on top of the cylindrical portion 31a of the motor housing 31. The motor frame 40 is made of metal (e.g., aluminum). A through-hole 40a is formed in the center of the motor frame 40, through which the rotating shaft 32 passes. A second bearing 42 is attached to the motor frame 40. The first bearing 41 and the second bearing 42 rotatably support the rotating shaft 32.

[0022] A sensor magnet 35 is attached to the upper end of the rotating shaft 32. The sensor magnet 35 rotates together with the rotating shaft 32. The sensor magnet 35 has one or more north poles and one or more south poles. The sensor magnet 35 rotates together with the rotating shaft 32.

[0023] The control unit 10 includes a wiring board 1 and a connector assembly 4. The control unit 10 is an example of an "electronic control device." The wiring board 1 includes a substrate 11 and a control circuit 2. The substrate 11 has electrical insulation properties. The substrate 11 is formed in a flat plate shape. The wiring board 1 is, for example, a multilayer printed circuit board in which multiple insulating layers and multiple conductor layers are stacked.

[0024] The wiring board 1 is fixed to the motor housing 31 by, for example, screws. The wiring board 1 may be fixed to the cover 3. The wiring board 1 may be fixed to the connector ASSY 4. The wiring board 1 is covered by the cover 3. The cover 3 is fixed to the motor housing 31. The cover 3 has a function of protecting the wiring board 1 from electromagnetic noise and a function of suppressing leakage of electromagnetic noise from the wiring board 1. The cover 3 is made of metal (for example, aluminum).

[0025] 2, the control circuit 2 includes a CPU 21, inverter circuits 25 and 26 (see FIG. 3), an input circuit 23, a power supply circuit 24, and an FET driver circuit 22. The CPU 21 performs, for example, calculations to control the rotation of the motor 30. The CPU 21 may be provided on the switching element mounting surface 2a of the wiring board 1 or on the non-switching element mounting surface 2b. In this embodiment, the control circuit 2 includes one CPU 21.

[0026] The inverter circuits 25, 26 (first inverter circuit 25 and second inverter circuit 26) supply AC power to the motor 30 (see FIG. 1). The inverter circuits 25, 26 include, for example, field-effect transistors, smoothing capacitors, and choke coils. The field-effect transistors perform current switching. The smoothing capacitors suppress voltage fluctuations associated with switching. The choke coils suppress noise leakage from the control unit 10 to the outside and noise inflow from the outside to the control unit 10.

[0027] The inverter circuits 25 and 26 each include a bridge circuit that connects the windings 30a of each phase of the motor 30 to the power supply 9 (battery). Each bridge circuit supplies current to each of the three-phase (U, V, W) windings 30a of the motor 30.

[0028] The input circuit 23 receives various input signals. Specific examples of the input signals include information from the sensors 29, the voltages of various parts in the inverter circuit, the magnitude of the drive current of the motor 30 detected by the inverter circuit, and the rotation angle detected by the MR sensor 20. Specific examples of the information from the sensors 29 include the vehicle speed detected by a vehicle speed sensor and the steering torque of the steering wheel detected by a torque sensor.

[0029] The power supply circuit 24 determines the power supply voltage required for the operation of electronic circuits such as the CPU 21. At least one power supply circuit 24 is provided. The FET driver circuit 22 (FET: Field Effect Transistor) drives the field effect transistors of the inverter circuits 25 and 26. The control circuit 2 may also include a torque sensor interface circuit, a vehicle communication interface circuit, etc.

[0030] The UVW terminals of the motor 30 are electrically connected to the wiring board 1. By electrically connecting the UVW terminals to the wiring board 1, a current is supplied from the inverter circuit to the motor 30, causing the rotating shaft 32 to rotate. The UVW terminals are joined to the wiring board 1 by, for example, partial jet soldering.

[0031] As shown in Fig. 1, a magnetoresistive sensor (hereinafter referred to as "MR sensor") 20 is mounted on a wiring board 1. The MR sensor 20 is mounted, for example, on a non-switching element surface 2b (the lower surface in Fig. 1) of the wiring board 1. The MR sensor 20 detects the rotation angle of the rotating shaft 32 by detecting a magnetic field generated by a sensor magnet 35. By improving the rotation angle detection accuracy, the motor 30 can be rotated with good controllability.

[0032] The MR sensor 20 is disposed, for example, in an area overlapping with the sensor magnet 35 when viewed from the axial direction of the motor 30. By disposing the MR sensor 20 in an area overlapping with the sensor magnet 35, the accuracy of detecting the rotation angle can be improved. The MR sensor 20 may also be disposed on the switching element mounting surface 2a of the wiring board 1. The MR sensor 20 may also be disposed outside the area overlapping with the sensor magnet 35.

[0033] 1, the connector ASSY 4 connects a battery voltage line, a ground line, and the like required for controlling and driving the motor 30 to the control unit 10. The connector ASSY 4 has, for example, a plurality of connectors.

[0034] The connector ASSY 4 can combine, for example, a battery voltage line, a ground line, a torque sensor signal, a vehicle communication signal, etc. The connector ASSY 4 may also include a connector for the torque sensor signal and the vehicle communication signal, separate from the connectors for the battery voltage line and the ground line, depending on the vehicle design situation, for example.

[0035] The connector ASSY 4 has, for example, metal bus bars, terminals, etc. extending from the terminals of each connector. The connector ASSY 4 is electrically connected to the wiring board 1. The connector ASSY 4 is, for example, a component that integrally combines a connector, bus bars, terminals, etc. The connector terminals (connector terminals) and the wiring board 1 are joined by, for example, partial jet soldering. The connector ASSY 4 is provided on the cover 3.

[0036] The control unit 10 is provided integrally with the motor 30. Therefore, the electric power steering device 100 is an integrated type electric power steering device.

[0037] FIG. 3 is a plan view of the switching element mounting surface 2a of the wiring board 1. As shown in FIG. 3, in this embodiment, the wiring board 1 controls the motor 30 using two systems (a first system and a second system). Each system includes an inverter circuit, a power supply relay, and a reverse connection protection relay in a path for supplying power from a power source to the motor 30. Specifically, the first system includes a first inverter circuit 25, a power supply relay switching element 271 (27), and a reverse connection protection relay switching element 281 (28). The second system includes a second inverter circuit 26, a power supply relay switching element 272 (27), and a reverse connection protection relay switching element 282 (28). Note that, although the wiring board 1 controls the motor 30 using two systems in this embodiment, the wiring board of the electric power steering device according to this embodiment may control the motor using a single system.

[0038] The first inverter circuit 25 supplies AC power to the motor 30 (see FIG. 1 ). The second inverter circuit 26 supplies AC power to the motor 30 (see FIG. 1 ) via a path different from that of the first inverter circuit 25. The reference symbols of the elements of the inverter circuits 25 and 26 include reference symbols (u, v, w) corresponding to the phases (U, V, W) of the motor 30.

[0039] The first inverter circuit 25 has upper arm switching elements 25uU, 25uV, 25uW, lower arm switching elements 25dU, 25dV, 25dW, motor relay switching elements 25mU, 25mV, 25mW, and shunt resistors 25rV, 25rW, 25rU.

[0040] The second inverter circuit 26 has upper arm switching elements 26uU, 26uV, 26uW, lower arm switching elements 26dU, 26dV, 26dW, motor relay switching elements 26mU, 26mV, 26mW, and shunt resistors 26rV, 26rW, 26rU.

[0041] The upper arm switching elements 25uU, 25uV, 25uW, 26uU, 26uV, and 26uW are connected to, for example, the positive electrode of the power supply 9 (see FIG. 2). The lower arm switching elements 25dU, 25dV, 25dW, 26dU, 26dV, and 26dW are connected to, for example, the negative electrode of the power supply 9 (see FIG. 2).

[0042] Motor relay switching elements 25mU, 25mV, 25mW, 26mU, 26mV, and 26mW are provided as motor relays.

[0043] The power supply relay switching elements 271 and 272 (power supply relay switching element 27 shown in FIG. 2) function as a power supply relay. The power supply relay can switch between conduction and interruption from the power supply to the motor 30.

[0044] The reverse polarity protection relay switching elements 281, 282 (reverse polarity protection relay switching element 28 shown in FIG. 2) function as reverse polarity protection relays. The reverse polarity protection relays protect the inverter circuit from reverse current flow when the power supply is reversely connected. The reverse polarity protection relays are connected so that the parasitic diodes are oriented in the opposite direction to the power supply relay.

[0045] The wiring board 1 may or may not include a motor relay, a power supply relay, and a reverse polarity protection relay.

[0046] FIG. 4 is a plan view of the switching element 60. In FIG. 4, an X direction and a Y direction are defined. The X direction and the Y direction are directions along the back surface 61a of the element body 61. The X direction is the left-right direction in FIG. 4. The Y direction is the up-down direction in FIG. 4. The Y direction is orthogonal to the X direction. The upside in FIG. 4 is the +Y side. The -Y side is the direction opposite to the +Y side.

[0047] At least one switching element 60 is mounted on the wiring board 1. Examples of the switching element 60 include upper arm switching elements 25uU, 25uV, 25uW, 26uU, 26uV, and 26uW, lower arm switching elements 25dU, 25dV, 25dW, 26dU, 26dV, and 26dW, power supply relay switching elements 27, 271, and 272, and reverse connection protection relay switching elements 28, 281, and 282 (see FIG. 3 ).

[0048] 4, the switching element 60 includes an element body 61 and an electrode 62. A back surface 61a of the element body 61 is rectangular and has two edges 61b parallel to the X direction and two edges 61c parallel to the Y direction.

[0049] The electrode 62 has a back surface electrode 63 and a plurality of lead electrodes 64. The electrode 62 is formed on the back surface 61 a of the element body 61. The electrode 62 is a conductive layer (metal layer) made of metal. The back surface electrode 63 has a rectangular shape with two edges 63 a parallel to the X direction and two edges 63 b parallel to the Y direction.

[0050] The lead electrodes 64 extend outward (toward the -Y side) from the -Y side edge 63a of the back surface electrode 63. The lead electrodes 64 are formed in a strip shape extending toward the -Y side. The multiple lead electrodes 64 may have the same length. The multiple lead electrodes 64 are formed at intervals in the X direction. The multiple lead electrodes 64 are formed, for example, at equal intervals. The lead electrodes 64 are formed integrally with the back surface electrode 63. A portion including the tip of the lead electrode 64 protrudes toward the -Y side from the -Y side edge 61b of the back surface 61a in a plan view. The width (dimension in the X direction) of the lead electrodes 64 is smaller than the width of the back surface electrode 63. In this embodiment, the number of lead electrodes 64 is four. The number of lead electrodes is not limited to multiple, and may be one.

[0051] 5 is a plan view of a land pattern 70 in the first embodiment. In FIG. 5, the X and Y directions are defined in the same manner as in FIG. 4. As shown in FIG. 5, the land pattern 70 is formed on the surface (switching element mounting surface 2a) of the wiring board 1 (see FIG. 3). The land pattern 70 is a conductive layer (metal layer) made of metal. The land pattern 70 is provided for surface mounting the switching element 60 on the wiring board 1. The electrodes 62 (see FIG. 4) of the switching element 60 are joined to the land pattern 70 by soldering.

[0052] The land pattern 70 has a first portion 71 and a plurality of second portions 72. The first portion 71 and the second portion 72 are exposed surfaces of the conductive layer (metal layer). The first portion 71 is a portion to which the back electrode 63 of the switching element 60 (see FIG. 4) is soldered. The second portion 72 is a portion to which the lead electrode 64 is soldered.

[0053] The first portion 71 has a rectangular shape having two edges 71a parallel to the X direction and two edges 71b parallel to the Y direction.

[0054] The second portion 72 is separated from the first portion 71 by the non-conductive resist portion 73. Specifically, the second portion 72 is located on the -Y side away from the -Y side edge 71a of the first portion 71. The second portion 72 has a rectangular shape. For example, the second portion 72 has a rectangular shape with long sides along the Y direction. The width (dimension in the X direction) of the second portion 72 is smaller than the width of the first portion 71.

[0055] The second portions 72 may have the same length. The second portions 72 are formed at intervals in the X direction. The second portions 72 are formed, for example, at equal intervals. The pitch P1 of the second portions 72 in the X direction (the distance between the center lines of adjacent second portions 72) is desirably equal to the pitch P2 of the lead electrodes 64 (see FIG. 4). In this embodiment, the number of second portions 72 is the same as the number of lead electrodes 64.

[0056] When the first portions 71 are positioned to overlap the back surface electrodes 63 (see FIG. 4 ), the second portions 72 each overlap the lead electrodes 64. The first portions 71 are placed over the back surface electrodes 63 and soldered to be electrically connected to the back surface electrodes 63. The second portions 72 are placed over the lead electrodes 64 and soldered to be electrically connected to the lead electrodes 64.

[0057] The non-conductive resist portion 73 is formed between the second portion 72 and the first portion 71. The non-conductive resist portion 73 separates the first portion 71 from the second portion 72. The non-conductive resist portion 73 has, for example, a rectangular shape with the same width as the second portion 72.

[0058] The non-conductive resist portion 73 is made of, for example, solder resist. Examples of solder resist that can be used include alkaline development type solder resist, thermosetting type solder resist, and ultraviolet curing type solder resist. The non-conductive resist portion is an example of a non-conductive coating portion (non-conductive portion). The non-conductive coating portion may be made of a material other than solder resist (for example, resin) as long as it is non-conductive and can regulate the flow of solder.

[0059] The non-conductive resist portion 73 desirably has a thickness that is higher than the surface of the second portion 72. This makes it difficult for the solder to move from the second portion 72 to the first portion 71.

[0060] The operation of the control circuit 2 shown in Fig. 2 will be described. The CPU 21 calculates the magnitude of the drive current to be supplied to each winding 30a of the motor 30 based on an input signal acquired via the input circuit 23. Based on the calculation result, the CPU 21 issues control instructions to the inverter circuits 25, 26. Control by the inverter circuits 25, 26 is performed for each phase (U, V, W) of the motor 30. The inverter circuits 25, 26 cause a predetermined current to flow through the winding 30a of each phase (U, V, W).

[0061] The lower end of the rotating shaft 32 of the motor 30 is used as an output end (see FIG. 1). A driven object (e.g., a steering system of a vehicle) is connected to the lower end of the rotating shaft 32. A reducer or the like may be interposed between the rotating shaft 32 and the driven object. The output of the motor 30 is transmitted to the driven object via the rotating shaft 32.

[0062] According to the first embodiment, in the land pattern 70, the first portion 71 to which the back surface electrode 63 is soldered and the second portion 72 to which the lead electrode 64 is soldered are separated by the non-conductive resist portion 73. This prevents the solder from moving between the first portion 71 and the second portion 72. This prevents the solder in the second portion 72 from flowing into the first portion 71. Therefore, when soldering the lead electrode 64 to the second portion 72, a sufficient amount of solder can be secured for joining the lead electrode 64, facilitating the formation of a solder fillet. This improves the connection reliability of the lead electrode 64.

[0063] Second Embodiment. Figure 6 is a plan view of a land pattern 170 in a second embodiment. Components common to the other embodiments are assigned the same reference numerals and will not be described further. As shown in Figure 6, the land pattern 170 is formed on the surface (switching element mounting surface 2a) of the wiring substrate 1 (see Figure 3). Electrodes 62 (see Figure 4) of the switching elements 60 are joined to the land pattern 170 by soldering. The control unit (electronic control device) can use the land pattern 170 in place of the land pattern 70 (see Figure 5).

[0064] The land pattern 170 has a first portion 71 and a plurality of second portions 172. The first portion 71 is a portion to which the back surface electrode 63 of the switching element 60 (see FIG. 4) is soldered. The second portions 172 are portions to which the lead portion electrodes 64 are soldered.

[0065] The second portion 172 is formed separately from the first portion 71. More specifically, the second portion 172 is located on the -Y side away from the -Y side edge 71a of the first portion 71. The second portion 172 has a rectangular shape. For example, the second portion 172 has a rectangular shape with long sides along the Y direction. The width (dimension in the X direction) of the second portion 172 is smaller than the width of the first portion 71.

[0066] When the first portions 71 are positioned to overlap the back surface electrodes 63 (see FIG. 4 ), the second portions 172 each overlap the lead electrode 64. The first portions 71 are placed over the back surface electrodes 63 and soldered to be electrically connected to the back surface electrodes 63. The second portions 172 are placed over the lead electrodes 64 and soldered to be electrically connected to the lead electrodes 64.

[0067] According to the second embodiment, in the land pattern 170, the first portion 71 to which the back surface electrode 63 is soldered and the second portion 172 to which the lead electrode 64 is soldered are formed separately, which makes it possible to prevent the solder in the second portion 172 from flowing into the first portion 71. Therefore, when soldering the lead electrode 64 to the second portion 172, a sufficient amount of solder can be secured for joining the lead electrode 64, making it easy to form a solder fillet. This improves the connection reliability of the lead electrode 64.

[0068] Embodiment 3. Figure 7 is a plan view of a land pattern 270 in embodiment 3. Components common to other embodiments are assigned the same reference numerals and will not be described further. As shown in Figure 7, the land pattern 270 is formed on the surface (switching element mounting surface 2a) of the wiring substrate 1 (see Figure 3). The electrodes 62 of the switching elements 60 (see Figure 4) are joined to the land pattern 270 by soldering. The control unit (electronic control device) can use the land pattern 270 in place of the land pattern 70 (see Figure 5).

[0069] The land pattern 270 has a first portion 71, a plurality of second portions 273, and a plurality of bridging portions 274. The first portion 71 is a portion to which the back surface electrode 63 of the switching element 60 (see FIG. 4) is soldered. The second portion 273 is a portion to which the lead portion electrode 64 is soldered.

[0070] The second portion 273 is located on the -Y side of the -Y side edge of the first portion 71. The second portion 273 has a rectangular shape. For example, the second portion 273 has a rectangular shape with long sides along the Y direction. The width (dimension in the X direction) of the second portion 273 is smaller than the width of the first portion 71.

[0071] The bridging portion 274 connects the first portion 71 and the second portion 273. More specifically, the bridging portion 274 connects the −Y side edge of the first portion 71 and the +Y side edge of the second portion 273. The first portion 71, the second portion 273, and the bridging portion 274 are integrally formed.

[0072] The bridging portion 274 is defined by a plurality of non-conductive resist portions 275. The plurality of non-conductive resist portions 275 are formed at intervals in the X direction. The non-conductive resist portions 275 are formed in a rectangular shape. The bridging portion 274 is a conductive layer (metal layer) exposed between adjacent non-conductive resist portions 275. The bridging portion 274 is defined by the non-conductive resist portions 275 so that its width (dimension in the X direction) is narrower than that of the second portion 273.

[0073] When the first portions 71 are positioned to overlap the back surface electrodes 63 (see FIG. 4 ), the second portions 273 each overlap the lead electrodes 64. The first portions 71 are placed over the back surface electrodes 63 and soldered to be electrically connected to the back surface electrodes 63. The second portions 273 are placed over the lead electrodes 64 and soldered to be electrically connected to the lead electrodes 64.

[0074] According to the third embodiment, the width of the bridge portion 274 connecting the first portion 71 and the second portion 273 of the land pattern 270 is narrow, which prevents the solder in the second portion 273 from flowing into the first portion 71. Therefore, when soldering the lead electrode 64 to the second portion 273, a sufficient amount of solder can be secured for joining the lead electrode 64, making it easier to form a solder fillet. This improves the connection reliability of the lead electrode 64.

[0075] Fourth Embodiment. Figure 8 is a plan view of a land pattern 370 in a fourth embodiment. Components common to the other embodiments are assigned the same reference numerals and will not be described further. As shown in Figure 8, the land pattern 370 is formed on the surface (switching element mounting surface 2a) of the wiring substrate 1 (see Figure 3). The electrodes 62 of the switching elements 60 (see Figure 4) are joined to the land pattern 370 by soldering. The control unit (electronic control device) can use the land pattern 370 in place of the land pattern 70 (see Figure 5).

[0076] The land pattern 370 has a first portion 71, a plurality of second portions 372, and a plurality of bridging portions 373. The first portion 71 is a portion to which the back surface electrode 63 of the switching element 60 (see FIG. 4) is soldered. The second portion 372 is a portion to which the lead portion electrode 64 is soldered.

[0077] The second portion 372 is located on the -Y side of the -Y side edge of the first portion 71. The second portion 372 has a rectangular shape. For example, the second portion 372 has a rectangular shape with long sides along the Y direction. The width (dimension in the X direction) of the second portion 372 is smaller than the width of the first portion 71.

[0078] The bridging portion 373 connects the first portion 71 and the second portion 372. More specifically, the bridging portion 373 connects the −Y side edge of the first portion 71 and the +Y side edge of the second portion 372. The width (dimension in the X direction) of the bridging portion 373 is smaller than the width of the second portion 372. The first portion 71, the second portion 372, and the bridging portion 373 are integrally formed.

[0079] When the first portions 71 are positioned to overlap the back surface electrodes 63 (see FIG. 4 ), the second portions 372 each overlap the lead electrode 64. The first portions 71 are placed over the back surface electrodes 63 and soldered to be electrically connected to the back surface electrodes 63. The second portions 372 are placed over the lead electrodes 64 and soldered to be electrically connected to the lead electrodes 64.

[0080] According to the fourth embodiment, the width of the bridge portion 373 connecting the first portion 71 and the second portion 372 of the land pattern 370 is narrow, which prevents the solder in the second portion 372 from flowing into the first portion 71. Therefore, when soldering the lead electrode 64 to the second portion 372, a sufficient amount of solder can be secured for joining the lead electrode 64, making it easier to form a solder fillet. This improves the connection reliability of the lead electrode 64.

[0081] The technical scope of the present disclosure is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present disclosure. In Fig. 2, the motor line connected to the winding 30a of the motor 30 is one system, but the motor line may be two or more systems. In Fig. 2, the battery line and ground line connected to the power source 9 are each one system, but these may be two or more systems. The number of CPUs 21 included in the control circuit 2 is not limited to one, and may be multiple.

[0082] In the above-described embodiment, the steering control device 1000 including the electric power steering device 100 as a drive device has been given as an example of the steering control device, but the steering control device may be any device involved in changing the direction of travel of the vehicle. The drive device is not limited to an electric power steering device. For example, the drive device may be a steer-by-wire system in which the steering mechanism on the steering wheel side and the steering mechanism on the wheel side are mechanically separated.

[0083] 1... wiring board, 2a... switching element mounting surface, 10... control unit (electronic control device), 25uU, 25uV, 25uW, 26uU, 26uV, 26uW... upper arm side switching elements (switching elements), 25dU, 25dV, 25dW, 26dU, 26dV, 26dW... lower arm side switching elements (switching elements), 27, 271, 272... power supply relay switching elements (switching elements), 28, 281 , 282...Reverse connection protection relay switching element (switching element), 30...Motor, 60...Switching element, 62...Electrode, 63...Back surface electrode, 64...Lead portion electrode, 70, 170, 270, 370...Land pattern, 71...First portion, 72, 172, 273, 372...Second portion, 274, 373...Bridge portion, 73, 275...Non-conductive resist portion, 100...Electric power steering device (drive device), 1000...Steering control device

Claims

1. An electronic control device comprising a wiring board carrying at least one switching element in a path for supplying power from a power source to a motor, the wiring board having a land pattern on the surface of the wiring board to which the electrode of the switching element, which has an electrode in which a back electrode and a lead electrode are integrated, is soldered, and the land pattern has a first portion to which the back electrode is soldered and a second portion to which the lead electrode is soldered, separated by a non-conductive resist.

2. An electronic control device comprising a wiring board carrying at least one switching element in a path for supplying power from a power source to a motor, the wiring board having a land pattern on the surface of the wiring board to which the electrode of the switching element, which has an electrode in which a back electrode and a lead electrode are integrated, is soldered, and the land pattern is formed by separating a first portion to which the back electrode is soldered and a second portion to which the lead electrode is soldered.

3. An electronic control device comprising: a wiring board carrying at least one switching element in a path for supplying power from a power source to a motor; the wiring board having a land pattern on a surface of the wiring board to which an electrode of the switching element, the electrode having a back electrode and a lead electrode integrated together, is soldered; the land pattern having: a first portion to which the back electrode is soldered; a second portion to which the lead electrode is soldered; and a bridging portion narrower than the second portion and connecting the first portion and the second portion; the bridging portion being defined and formed by a non-conductive resist.

4. An electronic control device comprising: a wiring board carrying at least one switching element in a path for supplying power from a power source to a motor; the wiring board having a land pattern on a surface of the wiring board to which an electrode of the switching element, the electrode having a back electrode and a lead electrode integrated together, is soldered; and the land pattern having: a first portion to which the back electrode is soldered; a second portion to which the lead electrode is soldered; and a bridging portion narrower than the second portion and connecting the first portion and the second portion.

5. A drive device comprising: an electronic control device according to any one of claims 1 to 4; and a motor controlled by said electronic control device.

6. A steering control device comprising the drive device according to claim 5.

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