Electronic devices, electric drive systems, and electric power steering systems

Abstract

Provided is an electronic device capable of preventing cracking in a base material that occurs from a starting point between metal wiring patterns in a flexible portion of a multilayer wiring board. An electronic component is mounted on a multilayer wiring board on which first and second component-mounting region portions are disposed with a foldable and flexible portion therebetween. Metal wires formed on the base material of the flexible portion include: a positive pole-side power supply wire and a negative pole-side power supply wire that feed power supply from a first electronic circuit formed in the first component-mounting region portion to a second electronic circuit formed in the second component-mounting region portion; a signal wire for exchanging signals between the first electronic circuit and the second electronic circuit; and a non-conductive wire that is not connected to any of the positive pole-side power supply wire, the negative pole-side power supply wire, the signal wire, and the first and second electronic circuits. The electronic device is characterized in that the non-conductive wire is disposed so as to be adjacent to at least one side of the positive pole-side power supply wire and be sandwiched by the positive pole-side power supply wire or the signal wire.

Description

[Technical Field]

[0001] The present invention relates to an electronic device in which electronic components are mounted on a flexible substrate (FLEX substrate), an electric drive system that integrally incorporates and controls this electronic device with an electric motor, and an electric power steering system that uses this electric drive system to provide steering force to a steering device. [Background technology]

[0002] Patent Document 1 describes a technique for preventing wiring breakage in an electrical system in which a panel (such as an LCD display) and a flexible circuit board are connected, by providing a reinforcing pattern (stiffener) near the outer edge of the flexible circuit board that is not electrically connected to other wiring. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] U.S. Patent Application Publication No. 2009 / 0231816 [Overview of the Initiative] [Problems that the invention aims to solve]

[0004] For example, the electronic devices incorporated into the motor unit of an electric drive system utilize a multilayer wiring board with a flexible section. This multilayer wiring board has a first and second component mounting area arranged on either side of a bendable flexible section. The first component mounting area has a power supply circuit that is supplied with power from an external source. On the other hand, the second component mounting area has a control circuit that is supplied with operating power from the first component mounting area via metal wiring formed in the flexible section, and also transmits and receives signals. The flexible section is then bent into a roughly U-shape, and the first and second component mounting areas are placed opposite each other and incorporated into the housing together with the electric motor. This allows for miniaturization of the electric drive system.

[0005] However, if power wiring is formed in the flexible section, it is necessary to ensure a predetermined spacing, for example 1 mm or more, between the positive and negative power wiring or signal wiring as a measure against migration and to prevent smoke and fire in the event of a short circuit. In areas where the wiring spacing is wide, the bending strength is reduced because only the base material is present, and cracks are more likely to occur in areas where the metal wiring pattern spacing is wide.

[0006] The present invention has been made in view of the above circumstances, and its objective is to provide an electronic device, an electric drive device, and an electric power steering device that can suppress cracks that occur in the substrate originating from between metal wiring patterns in the flexible portion of a multilayer wiring board. [Means for solving the problem]

[0007] According to one aspect of the present invention, an electronic device comprising: a multilayer wiring board in which a first component mounting area and a second component mounting area are arranged with a bendable flexible portion in between; a first electronic circuit formed in the first component mounting area and supplying power to the second component mounting area via the flexible portion; a second electronic circuit formed in the second component mounting area and operating by power supply from the first electronic circuit; metal wiring formed on the substrate of the flexible portion and electrically connecting the first electronic circuit and the second electronic circuit; and a housing that folds the multilayer wiring board at the flexible portion and houses the first and second component mounting areas facing each other, wherein the metal wiring includes a positive-side power supply wiring and a negative-side power supply wiring that supply power from the first electronic circuit to the second electronic circuit; a signal wiring that transmits and receives signals between the first electronic circuit and the second electronic circuit; and non-connected to the positive-side power supply wiring, the negative-side power supply wiring, the signal wiring, and the first and second electronic circuits. multiple The non-conductive wiring and the said multiple Non-conductive wiring is the positive side power supply wiring. Multiple non-conductive wires are provided adjacent to one side and between the positive-side power supply wiring and the signal wiring, and multiple non-conductive wires are provided adjacent to the opposite side of the positive-side power supply wiring and between the positive-side power supply wiring and the negative-side power supply wiring, and the width of each of the multiple non-conductive wires is smaller than the width of the positive-side power supply wiring. An electronic device characterized by the above is provided. [Effects of the Invention]

[0008] According to the present invention, in the metal wiring of the flexible portion, the base material of the portion adjacent to the positive power supply wiring with widened wiring intervals by measures against migration and short circuit can be reinforced with non-conductive wiring, and the bending strength can be improved. Thereby, cracks generated in the base material starting from between the patterns of the metal wiring can be suppressed.

Brief Description of the Drawings

[0009] [Figure 1] It is a schematic configuration diagram of an electric power steering apparatus according to an embodiment of the present invention. [Figure 2] It is an external perspective view of an electric drive device used in the electric power steering apparatus shown in FIG. 1. [Figure 3] It is an exploded perspective view of the electric drive device shown in FIG. 2. [Figure 4] It is an external perspective view of an electronic device used in the electric drive device shown in FIG. 3. [Figure 5] It is a perspective view showing a state where a multilayer wiring board is bent at a flexible portion in order to house the electronic device shown in FIG. 4 inside an exterior member of the electric drive device. [Figure 6] It is a plan view of a multilayer wiring board in the electronic device shown in FIG. 4. [Figure 7A] It shows the pattern of the metal wiring in the region surrounded by the dashed-dotted line in the flexible portion of the multilayer wiring board shown in FIG. 6, and it is the metal wiring on the surface layer. [Figure 7B] It shows the pattern of the metal wiring in the region surrounded by the dashed-dotted line in the flexible portion of the multilayer wiring board shown in FIG. 6, and it is the metal wiring on the inner layer. [Figure 8] It is a view showing an enlarged pattern of the metal wiring in the region surrounded by the dashed-dotted line in the flexible portion of FIG. 7A. [Figure 9] It is a plan view for explaining a preferable first pattern example of the metal wiring in the flexible portion of the multilayer wiring board. [Figure 10A]This is a plan view illustrating a preferred second pattern example of metal wiring in the flexible portion of a multilayer wiring board, showing the surface layer metal wiring. [Figure 10B] This is a plan view illustrating a preferred second pattern example of metal wiring in the flexible portion of a multilayer wiring board, showing the inner layer metal wiring. [Figure 11] This is a plan view illustrating a preferred third pattern example of metal wiring in the flexible portion of a multilayer wiring board. [Figure 12] This is a plan view illustrating a preferred fourth pattern example of metal wiring in the flexible portion of a multilayer wiring board. [Figure 13] This is a plan view illustrating a preferred fifth pattern example of metal wiring in the flexible portion of a multilayer wiring board. [Figure 14] This is a plan view illustrating a preferred sixth pattern example of metal wiring in the flexible portion of a multilayer wiring board. [Modes for carrying out the invention]

[0010] Embodiments of the present invention will be described below with reference to the drawings. Figure 1 is a schematic diagram of an electric power steering system according to an embodiment of the present invention. This electric power steering system 111 includes a steering mechanism 112 for steering based on driver input and a steering assist mechanism 113 for assisting the driver's steering operation. An electric motor 20 in an electric drive unit (electric power pack) 10 is used to assist the steering force, and this electric motor 20 is controlled by a control unit (electronic device) 30 to assist the steering operation.

[0011] The electric drive unit 10 is mounted on a gear rack (not shown). The connector of this electric drive unit 10 is electrically connected to the battery power supply and electronic equipment for in-vehicle communication (CAN communication) via a power harness (not shown) and a signal harness, and is also electrically connected to the torque sensor 124 and the steering angle sensor 123 via a sensor harness 135.

[0012] The steering mechanism 112 includes a steering shaft 115 linked to the steering wheel 114 and a rack bar 118 linked to the tires 116 and 117. The steering shaft 115 and the rack bar 118 are linked via a rack and pinion mechanism 119.

[0013] The steering shaft 115 is constructed by connecting an input shaft 120, which is a first axial member that rotates integrally with the steering wheel 114, and an output shaft 121, which is a second axial member that is linked to the rack bar 118, with a torsion bar (not shown). One end of the input shaft 120 is connected to the steering wheel 114 in the axial direction, and the other end is connected to the torsion bar. One end of the output shaft 121 is connected to the torsion bar in the axial direction, and the other end is linked to the rack bar 118.

[0014] Then, the pinion teeth 121a formed on the outer circumference of the other end of the output shaft 121 mesh with the rack teeth 118a formed on one end of the rack bar 118 in the axial direction (longitudinal direction), thereby converting the rotational motion of the output shaft 121 into the axial motion of the rack bar 118 and transmitting it.

[0015] Furthermore, on the radially outer side (outer circumference) of the steering shaft 115, a steering angle sensor 123 for detecting the steering angle, which is the rotation angle of the steering shaft 115, and a torque sensor 124 for detecting the steering torque applied to the steering shaft 115 by the driver's steering operation are integrally provided as a single unit. The steering angle sensor 123 detects the steering angle based on the difference in rotation angles of a pair of gears that rotate in conjunction with the rotation of the steering shaft 115. The torque sensor 124 detects the steering torque based on the relative rotational displacement of the input shaft 120 and the output shaft 121.

[0016] Tires 116 and 117 are attached to both axial ends of the rack bar 118 via tie rods 125 and 126 and knuckle arms (not shown). When the rack bar 118 moves axially, the knuckle arms are pushed and pulled via the tie rods 125 and 126, which changes the orientation of the tires 116 and 117.

[0017] The steering assist mechanism 113 includes an electric motor (electric actuator) 20 that generates steering assist force, a control unit 30 that drives and controls the electric motor 20, and a transmission mechanism 133 that transmits the rotation of the electric motor 20 to the rack bar 118, and assists the axial movement of the rack bar 118 with the rotational force of the electric motor 20. The control unit 30 is connected to other ECUs, such as an ESC (Electronic Stability Control) control device, via the CAN bus 134, and exchanges information via CAN communication.

[0018] The electric motor 20 is driven and controlled based on the detection results of various sensors, such as the output signal S1 of the steering angle sensor 123 and the output signal S2 of the torque sensor 124, which are input to the control unit 30 via the sensor harness 135, the output signal S3 of the vehicle speed sensor (not shown) which is input via the CAN bus 134, and the output signal of the Hall IC which detects the rotation angle of the electric motor 20.

[0019] The transmission mechanism 133 includes a reduction gear that reduces the rotation of the electric motor 20, and a conversion mechanism that converts the rotation of the reduction gear into axial motion of the rack bar 118. The reduction gear consists of, for example, an input pulley fixed to rotate integrally with the drive shaft of the electric motor 20, an output pulley fixed to rotate integrally with a nut that acts as a conversion mechanism, and a transmission member such as a belt or chain wound around these pulleys.

[0020] The conversion mechanism can use, for example, a ball screw mechanism using a cylindrical nut that surrounds the rack bar 118. A helical ball screw groove is formed on the inner circumference of the nut, and a helical ball screw groove is formed on the outer circumference of the rack bar 118. When the nut is inserted into the rack bar 118, a ball circulation groove is formed by the nut-side ball screw groove and the steering shaft-side ball screw groove.

[0021] The ball circulation groove is filled with multiple metal balls, and as the nut rotates, the balls move within the groove, causing the rack bar 118 to move axially relative to the nut. The ball screw mechanism converts the rotational motion of the electric motor 20 into linear motion, and the axial movement of the rack bar 118 pushes and pulls the knuckle arm via the tie rods 125 and 126, thereby applying steering force to the tires 116 and 117.

[0022] The reduction gear described above can be a worm gear having a worm shaft that is rotatably connected to the output shaft of the electric motor 20 and a worm wheel that rotates in mesh with the worm shaft. Alternatively, the conversion mechanism can also utilize a so-called rack and pinion mechanism, which consists of pinion teeth formed on the outer circumference of the other axial end of the output shaft that rotates integrally with the worm wheel, and rack teeth formed on the other axial end of the rack bar 118 that mesh with these pinion teeth.

[0023] Figure 2 is an external perspective view of the electric drive unit 10 used in the electric power steering system 111 shown in Figure 1, and Figure 3 is an exploded perspective view of the electric drive unit 10 shown in Figure 2. As shown in Figures 2 and 3, the electric drive unit 10 integrates an electronic device (control unit 30) with the electric motor 20 for control. The motor body 2, housed in an exterior member (cover) 1, has mounting components 3 for controlling the drive of the motor body 2, a multilayer wiring board (PCB, also called a printed circuit board) 4 on which various electronic components are mounted, a connector block 5, etc. attached to it, and is covered by an exterior member (cover) 6.

[0024] Exterior member 1 and exterior member 6 form a pair and are joined together via a sealing material (not shown), forming a housing that accommodates the motor body 2, mounted components 3, a multilayer wiring board 4 on which various electronic components are mounted, and a connector block 5. The motor shaft and the gear 2a attached to this motor shaft protrude from one side of exterior member 1, and an opening 6a is formed on the opposing side of exterior member 6, from which a connection opening 5c ​​provided on the front 5a side of the connector block 5 protrudes.

[0025] The connector block 5 shown in Figures 2 and 3 is a molded body in which a portion of the terminal member is sealed. The front surface 5a of the connector block 5 has a connection opening 5c ​​on which the terminal member is connected to the terminal member of the mating connector. Thickened collars are formed at the four corners of the connector block 5 to increase its durability. Screws 7-1 to 7-4 are inserted through these collars and screwed into the screw receiving portions 8-1 to 8-4 of the outer casing member 1, thereby fixing the multilayer wiring board 4 and the connector block 5 together with the mounted components 3.

[0026] As shown in Figure 4, the multilayer wiring board 4 has a configuration in which a first component mounting area 4a and a second component mounting area 4b, corresponding to the planar shape of the back surface 5b of the connector block 5, are arranged and joined together with a bendable flexible section 4c in between. Connector sections 13-1 to 13-4, to which power and signals are supplied from the outside, are provided in the first component mounting area 4a. A power supply circuit (first electronic circuit) 11 is formed in the first component mounting area 4a, and a control system circuit (second electronic circuit) 12 is formed in the second component mounting area 4b. The power supply circuit 11 supplies power to the control system circuit 12 in the second component mounting area 4b via metal wiring formed in the flexible section 4c, and the control system circuit 12 operates by the power supply from the first component mounting area 4a.

[0027] In the flexible section 4c, an intermediate rigid section 14 remains in its six-layer structure in the center to ensure a printing surface for barcodes, etc. A pair of grooves 15-1, 15-2 form thin-walled sections on both sides of this intermediate rigid section 14. This intermediate rigid section 14 is not essential, and the entire flexible section 4c may be made thinner. Here, the entire area between the first component mounting area 4a and the second component mounting area 4b, including the intermediate rigid section 14, is referred to as the flexible section 4c.

[0028] Then, as shown in Figure 5, the multilayer wiring board 4 is bent at the flexible portion 4c, and the first and second component mounting areas 4a and 4b are placed facing each other and housed in the exterior member 6 which serves as the housing. That is, as shown in Figure 3, first the second component mounting area 4b is placed on the back surface 5b, the first component mounting area 4a is placed on top of the second component mounting area 4b, the multilayer wiring board 4 is mounted on the back surface 5b of the connector block 5, and then covered and housed with the exterior member 6.

[0029] Figure 6 is a plan view of the multilayer wiring board 4 in the electronic device shown in Figure 4. The multilayer wiring board 4 has a first component mounting area 4a and a second component mounting area 4b, separated by a bendable flexible section 4c, and power is supplied from the power supply circuit 11 to the control circuit 12 as indicated by arrow AA. The flexible section 4c uses a thin, flexible substrate as an insulating substrate, and metal wiring is formed in the surface layer and inner layer, respectively.

[0030] Figures 7A and 7B show the metal wiring patterns in the region enclosed by the dashed line BL1 in the flexible portion 4c of the multilayer wiring board 4 shown in Figure 6, respectively. Figure 7A shows the metal wiring of the surface layer, and Figure 7B shows the metal wiring of the inner layer. Figure 8 shows a magnified view of the metal wiring pattern in the region enclosed by the dashed line BL2 in the flexible portion of Figure 7A.

[0031] As shown in Figure 7A, metal wiring is provided in a parallel linear pattern along the width direction of the surface of the flexible portion 4c (in the direction perpendicular to the direction in which the first and second component mounting areas 4a and 4b are arranged), electrically connecting the power supply circuit (first electronic circuit) 11 and the control circuit (second electronic circuit) 12. Positive-side power supply wiring 161 and 162, which supply power from the power supply circuit 11 to the control circuit 12, is arranged near both edges of the flexible portion 4c. Signal wiring 171, 172, ... (or negative-side power supply wiring) is arranged in the center for the exchange of signals between the power supply circuit 11 and the control circuit 12.

[0032] Non-conductive wires 191 and 192 are positioned adjacent to one side of the positive-side power supply wire 161, sandwiched between the signal wire 171. Also, non-conductive wires 193 and 194 are positioned adjacent to the opposite side of the positive-side power supply wire 161, sandwiched between the negative-side power supply wire 181. The wiring widths of non-conductive wires 191, 192 and 193, 194 are each narrower than the wiring width of the positive-side power supply wire 161. These non-conductive wires 191, 192, 193, and 194 are not connected to the positive-side power supply wires 161, 162, the signal wires 171, 172, ..., the negative-side power supply wire 181, the power supply circuit 11, and the control circuit 12, and are electrically floating.

[0033] Similarly, non-conductive wires 195, 196 and 197, 198 are arranged adjacent to both sides of the positive-side power supply wire 162. The wiring width of these non-conductive wires 195, 196, 197, 198 is narrower than the wiring width of the positive-side power supply wire 162. These non-conductive wires 195, 196, 197, 198 are not connected to the positive-side power supply wires 161, 162, signal wires 171, 172, ..., negative-side power supply wire 182, power supply circuit 11, and control circuit 12, and are electrically floating. Furthermore, it is preferable to form multiple non-conductive wires on at least one side of the positive-side power supply wires 161 and 162. In this example, non-conductive wires 19 are also formed on both edges in the width direction of the surface layer, acting as reinforcing materials at both ends of the flexible portion 4c. i ,19 j A system is in place.

[0034] As shown in Figure 7B, metal wiring is provided in the width direction of the inner layer of the flexible section 4c, similar to the surface layer, formed in a parallel linear pattern, to electrically connect the power supply circuit 11 and the control circuit 12. Positive-side power supply wiring 163 and 164, which supply power from the power supply circuit 11 to the control circuit 12, are positioned near both edges of the flexible section 4c, corresponding to the positive-side power supply wiring 161 and 162 of the surface layer. Signal wiring 173 and negative-side power supply wiring 184 are located in the center.

[0035] Then, adjacent to one side of the positive electrode side power supply wiring 163, non-conductive wirings 199, 19 are arranged so as to be sandwiched by the signal wiring 173. Also, adjacent to the opposite side of the positive electrode side power supply wiring 163, non-conductive wirings 19 10 , 19 11 , 19 12 are arranged so as to be sandwiched by the negative electrode side power supply wiring 185. The wiring widths of the non-conductive wirings 199, 19 10 and the non-conductive wirings 19 11 , 19 12 are each narrower than the wiring width of the positive electrode side power supply wiring 163. These non-conductive wirings 199, 19 10 , 19 11 , 19 12 are not connected to the positive electrode side power supply wiring 163, the signal wiring 173, the negative electrode side power supply wiring 184, the power supply system circuit 11, and the control system circuit 12, and are in an electrically floating state.

[0036] Similarly, on both sides of the positive electrode side power supply wiring 164, non-conductive wirings 19 12 , 19 13 and non-conductive wirings 19 14 , 19 15 are arranged adjacent to each other. The wiring widths of these non-conductive wirings 19 12 , 19 13 , 19 14 , 19 15 are narrower than the wiring width of the positive electrode side power supply wiring 164. These non-conductive wirings 19 12 , 19 13 , 19 14 , 19 15 are not connected to the positive electrode side power supply wiring 164, the signal wiring, the negative electrode side power supply wiring 186, the power supply system circuit 11, and the control system circuit 12, and are in an electrically floating state. Note that it is preferable to form a plurality of non-conductive wirings on at least one side of the positive electrode side power supply wirings 161, 162. Also, in this example, non-conductive wirings 19 i , 19 j corresponding to positions at both edges in the width direction of the inner layer serve as reinforcing members at both ends of the flexible portion 4c, and non-conductive wirings 19 k , 19 l are provided.

[0037] Figure 9 is a plan view illustrating a preferred first pattern example of metal wiring in the flexible portion 4c of the multilayer wiring board 4. In this example, the spacing ΔD1 between the positive-side power wiring 16 and the negative-side power wiring 18 is greater than the spacing ΔD2 between the signal wirings 17, 17.

[0038] Figures 10A and 10B are plan views illustrating a preferred second pattern example of metal wiring in the flexible portion 4c of the multilayer wiring board 4. In this example, a positive-side power supply wiring 16 (or a non-conductive wiring) of the same potential as shown in Figure 10B is formed in the inner layer directly beneath the positive-side power supply wiring 16 of the surface layer of the flexible portion 4c shown in Figure 10A.

[0039] Figure 11 is a plan view illustrating a preferred third pattern example of metal wiring in the flexible portion 4c of the multilayer wiring board 4. In this example, the wiring width ΔW1 of the non-conductive wiring 19 is wider (wiring width ΔW2) near the first and second component mounting areas 4a and 4b. Figure 11 typically shows the vicinity of the first component mounting area 4a.

[0040] Figure 12 is a plan view illustrating a preferred fourth pattern example of metal wiring in the flexible portion 4c of the multilayer wiring board 4. In this example, the positive-side power supply wiring 16 is located near the center of the flexible portion 4c. Non-conductive wirings 19, 19, ... are arranged adjacent to both sides of this positive-side power supply wiring 16, sandwiched between signal wirings 17. In the embodiment described above, an example was explained in which the positive-side power supply wiring 161, 162, 163, and 164 are provided near both edges of the flexible portion 4c, but they can also be provided near the center.

[0041] Figure 13 is a plan view illustrating a preferred fifth pattern example of metal wiring in the flexible portion 4c of the multilayer wiring board 4. In this example, the distance ΔD1 between the positive-side power wiring 16 and the negative-side power wiring 18, and the distance ΔD3 between the positive-side power wiring 16 and the signal wiring 17 are set to satisfy the relationship "ΔD1 ≥ ΔD3". By setting the intervals ΔD1 and ΔD3 to satisfy the above relationship, migration can be suppressed.

[0042] Figure 14 is a plan view illustrating a preferred fifth pattern example of metal wiring in the flexible portion 4c of the multilayer wiring board 4. In this example, three signal wires 17 are placed between the positive-side power supply wire 16 and the signal wire 17, and two signal wires are placed between the positive-side power supply wire 16 and the negative-side power supply wire 18, so that the distance ΔD4 between the positive-side power supply wire 16 and the negative-side power supply wire 18 and the distance ΔD5 between the positive-side power supply wire 16 and the signal wire 17 satisfy the relationship "ΔD4 < ΔD5". By setting the intervals ΔD4 and ΔD5 to satisfy the above relationship, noise can be suppressed.

[0043] Therefore, with the above configuration, the base material adjacent to the positive-side power supply wiring, where the spacing between wires has been widened to prevent migration and short circuits in the flexible part of the multilayer wiring board, can be reinforced with non-conductive wiring to improve bending strength, thereby suppressing cracks that originate in the base material between the metal wiring patterns.

[0044] The configurations and methods described in the embodiments described above are merely schematic representations to the extent that the present invention can be understood and implemented. Therefore, the present invention is not limited to the embodiments described, and can be modified in various forms as long as it does not deviate from the scope of the technical idea set forth in the claims.

[0045] For example, the explanation used the case where an electronic device is used as a control unit for an electric drive system, but it can also be applied to other devices and equipment. Furthermore, although this electric drive system was applied to a vehicle's electric power steering system and used to control the drive of the electric motor that assists steering force, it can also be used to generate steering force for an electric steering system, and is certainly not limited to application to a vehicle's steering system. Furthermore, although the above-described embodiment explained the case where non-conductive wiring is provided adjacent to both sides of the positive terminal power supply wiring, it may also be provided on only one side. [Explanation of Symbols]

[0046] 1...Exterior component (housing), 2...Motor body, 3...Mounted components, 4...Multilayer wiring board, 4a...First component mounting area, 4b...Second component mounting area, 4c...Flexible part, 5...Connector block, 5...Connector block, 6...Exterior component (housing), 10...Electric drive device (electric power pack), 11...Power supply circuit (first electronic circuit), 12...Control circuit (second electronic circuit), 16...Positive side power supply wiring, 17...Signal wiring, 18...Negative side power supply wiring, 19...Non-conductive wiring, 20...Electric motor, 30...Control unit (electronic device), 111...Electric power steering device

Claims

1. A multilayer wiring board in which a first component mounting area and a second component mounting area are arranged with a bendable flexible portion in between, A first electronic circuit formed in the first component mounting area and supplying power to the second component mounting area via the flexible portion, A second electronic circuit is formed in the second component mounting area and operates by power supply from the first electronic circuit, A metal wiring is formed on the substrate of the flexible part, which electrically connects the first electronic circuit and the second electronic circuit. An electronic device comprising: a housing that folds the multilayer wiring board at the flexible portion and houses it with the first and second component mounting areas facing each other, The aforementioned metal wiring is A positive-side power supply wiring and a negative-side power supply wiring that supply power from the first electronic circuit to the second electronic circuit, A signal wiring that transmits and receives signals between the first electronic circuit and the second electronic circuit, The positive terminal power supply wiring, the negative terminal power supply wiring, the signal wiring, and a plurality of non-conductive wirings that are not connected to the first and second electronic circuits, The plurality of non-conductive wirings are provided adjacent to one side of the positive-side power supply wiring and between the positive-side power supply wiring and the signal wiring, and also adjacent to the opposite side of the positive-side power supply wiring and between the positive-side power supply wiring and the negative-side power supply wiring. An electronic device characterized in that the width of each of the plurality of non-conductive wirings is smaller than the width of the positive electrode side power supply wiring.

2. The electronic device according to claim 1, characterized in that the signal wiring is provided on the central side in the width direction perpendicular to the direction in which the first and second component mounting areas in the flexible portion are arranged, and the positive side power wiring and the negative side power wiring are provided on the edge side than the signal wiring.

3. The electronic device according to claim 1, characterized in that the distance between the positive electrode power supply wiring and the negative electrode power supply wiring is greater than the distance between the signal wirings.

4. The electronic device according to claim 1, characterized in that a further positive electrode power supply wiring or non-conductive wiring is provided in the inner layer directly beneath the positive electrode power supply wiring in the flexible portion.

5. The electronic device according to claim 1, characterized in that the non-conductive wiring has a large wiring width in the vicinity of the first and second component mounting areas.

6. The electronic device according to claim 1, further comprising a connector portion provided in the first component mounting area and supplied with power from an external source, wherein the first electronic circuit is a power supply system circuit supplied with power from the connector portion, and the second electronic circuit is a control system circuit that operates based on the power supply voltage supplied from the power supply system circuit.

7. An electric drive device characterized in that the electronic device and electric motor described in claim 1 are integrated coaxially with the motor output shaft and housed in the housing, the electronic device is positioned on the opposite side from the output side of the electric motor, the electronic device is electrically connected to the outside via a harness, and power is supplied from this harness and control signals are input to control the electric motor.

8. An electric power steering device, characterized in that it is configured to apply steering force to a steering device using the electric motor in the electric drive device described in claim 7.

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