Patent Publication Number: US-2022225497-A1

Title: Electronic control device

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     The present application is a continuation application of International Patent Application No. PCT/JP2020/035198 filed on Sep. 17, 2020, which designated the U.S. and claims the benefit of priority from Japanese Patent Application No. 2019-183116 filed on Oct. 3, 2019. The entire disclosures of all of the above applications are incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     The present disclosure relates to an electronic control device. 
     BACKGROUND 
     A drive device in which a motor and a control unit are integrally formed is known. For example, an O-ring is provided between a motor case and a frame, and a frame member and a cover member are fixed by an adhesive to prevent water droplets and the like from entering the inside. 
     SUMMARY 
     The present disclosure provides an electronic control device. The electronic control device includes a plurality of drive control components and a substrate. The plurality of drive control components are grouped into systems. Each of systems is configured to control a control target independently. The substrate is divided into areas, corresponding to the systems, on which at least a part of the drive control components is mounted by each of the systems, and has layers stacked. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       The features and advantages of the present disclosure will become more apparent from the following detailed description made with reference to the accompanying drawings. In the drawings: 
         FIG. 1  is a schematic structural diagram showing a steering system according to an embodiment; 
         FIG. 2  is a cross-sectional view showing a drive device according to the embodiment; 
         FIG. 3  is a circuit diagram showing a drive device according to the embodiment; 
         FIG. 4  is a plan view showing a counter-motor surface of a control board according to the embodiment; 
         FIG. 5  is a cross sectional view taken along a line V-V of  FIG. 4 ; 
         FIG. 6  is a schematic diagram showing a slit and a minimum pattern gap according to the embodiment; 
         FIG. 7  is a schematic diagram showing a wiring pattern of a third layer according to the embodiment; 
         FIG. 8  is a schematic diagram showing a wiring pattern of a fifth layer according to the embodiment; 
         FIG. 9  is a schematic diagram showing a wiring pattern of a sixth layer according to the embodiment; and 
         FIG. 10  is a schematic diagram showing a state in which the fifth layer and the sixth layer are overlapped according to the embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     For example, when a wiring pattern is separated and one substrate is shared by a plurality of systems, if a conductive foreign matter is entered from the separated portion, there is a possibility that the plurality of systems may fail at the same time due to a short circuit between the systems. Even if it is configured to prevent foreign matter from entering from the outside, there is a possibility that a failure may occur due to foreign matter or ion migration that has entered from the beginning at the time of manufacture. The present disclosure provides an electronic control device capable of reducing a probability of simultaneous failure of a plurality of systems. 
     An exemplary embodiment of the present disclosure provides an electronic control device. An electronic control device includes a plurality of drive control components and a substrate. The plurality of drive control components are grouped into systems. Each of systems is configured to control a control target independently. The substrate is divided into areas, corresponding to the systems, on which at least a part of the drive control components is mounted by each of the systems, and has layers stacked. Each of the layers has a wiring pattern and forms a slit that divides the substrate into the areas defined as system areas. The slit has a width greater than a minimum pattern gap in the substrate. In the exemplary embodiment of the present disclosure, it is possible to suppress the occurrence of a short circuit between systems due to a foreign matter, ion migration, or the like, and thus it is possible to reduce the probability of simultaneous failure of the plurality of systems. 
     Embodiment 
     Hereinafter, an electronic control device according to the present disclosure will be described with reference to the drawings. The electronic control device according to one embodiment is shown in  FIGS. 1 to 10 . As shown in  FIG. 1 , a drive device  1  according to a first embodiment includes a motor  80  and an ECU  10  as an electronic control device, and is applied to an electric power steering device  8 , which assists a steering operation of a vehicle.  FIG. 1  shows an overall configuration of a steering system  90  including the electric power steering device  8 . The steering system  90  includes a steering wheel  91  as a steering member, a steering shaft  92 , a pinion gear  96 , a rack shaft  97 , wheels  98 , the electric power steering device  8 , and the like. 
     The steering wheel  91  is connected to the steering shaft  92 . The steering shaft  92  is provided with a torque sensor  94  for detecting a steering torque Trq. The torque sensor  94  is internally systematized into two systems, and the detected values of the two systems are output to the corresponding microcomputers  170  and  270 . The pinion gear  96  is provided at an axial end of the steering shaft  92 . The pinion gear  96  meshes with a rack shaft  97 . A pair of road wheels  98  is coupled at both ends of the rack shaft  97  via, for example, tie rods. When a driver of the vehicle rotates the steering wheel  91 , the steering shaft  92  connected to the steering wheel  91  rotates. A rotational movement of the steering shaft  92  is converted into a linear movement of the rack shaft  97  by the pinion gear  96 . The pair of road wheels  98  is steered to an angle corresponding to a displacement amount of the rack shaft  97 . 
     The electric power steering device  8  includes a drive device  1 , a reduction gear  89  as a power transmission unit that reduces the rotation of the motor  80  and transmits the rotation to the rack shaft  97 , and the like. The electric power steering device  8  of the present embodiment is a so-called “rack assist type”, but may be a so-called “column assist type” or the like that transmits the rotation of the motor  80  to the steering shaft  92 . 
     As shown in  FIGS. 2 and 3 , the motor  80  is a three-phase brushless motor. The motor  80  outputs part or all of a torque required for steering, and is driven by a power supplied from batteries  199  and  299  to rotate the reduction gear  89  forward and backward. 
     The motor  80  has a first motor winding  180  and a second motor winding  280 . The motor windings  180  and  280  have the same electrical characteristics and are wound about the stator  840  with electrical angles changed from each other by 30 degrees. Correspondingly, phase currents are controlled to be supplied to the motor windings  180  and  280  such that the phase currents have a phase difference φ of 30 degrees. By optimizing the current supply phase difference, the output torque can be improved. In addition, sixth-order torque ripple can be reduced, and noise and vibration can be reduced. In addition, since heat is also distributed and averaged by distributing the current, it is possible to reduce temperature-dependent system errors such as a detection value and torque of each sensor and increase the amount of current that is allowed to be supplied. The motor windings  180  and  280  do not have to be cancel-wound and may have different electrical characteristics. 
     Hereinafter, a combination of configurations relating to the energization control of the first motor winding  180  will be referred to as a first system L 1 , and a combination of configurations relating to the energization control of the second motor winding  280  will be referred to as a second system L 2 . The configuration of the first system L 1  is mainly numbered in the  100 &#39;s, the configuration of the second system L 2  is mainly numbered in the  200 &#39;s, and the configurations substantially similar to each other in the systems L 1  and L 2  are numbered so that the last two digits are the same, and a description of those configurations will be omitted as appropriate. As appropriate, an index of “1” is added to a component or a value related to the first system L 1 , and an index of “2” is added to a component or a value related to the second system L 2 . 
     As shown in  FIG. 2 , in the drive device  1 , the ECU  10  is integrally provided on one side in the axial direction of the motor  80  in a machine-electronics integrated type. The motor  80  and the ECU  10  may alternatively be provided separately. The ECU  10  is positioned coaxially with an axis Ax of the shaft  870  on the side opposite to the output shaft of the motor  80 . The ECU  10  may alternatively be provided on the output shaft side of the motor  80 . By adopting the mechanically-electrically integrated type, it may be possible to efficiently position the ECU  10  and the motor  80  in a vehicle having restriction for mounting space. 
     The motor  80  includes, in addition to the stator  840  and rotor  860 , a housing  830  that houses the stator  840  and the rotor  860 , or the like. The stator  840  is fixed to the housing  830  and the motor windings  180  and  280  are wound thereon. The rotor  860  is placed radially inside the stator  840  to be rotatable relative to the stator  840 . 
     The shaft  870  is fitted in the rotor  860  to rotate integrally with the rotor  860 . The shaft  870  is rotatably supported by the housing  830  through bearings  835  and  836 . The end portion of the shaft  870  on the ECU  10  side protrudes from the housing  830  to the ECU  10  side. A magnet  875  is placed at the end of the shaft  870  on the ECU  10  side. 
     The housing  830  has a cylindrical case  834 , a rear frame end  837  provided at one end of the case  834 , and a front frame end  838  provided at the other end of the case  834 . Lead wire insertion holes  839  are formed in the rear frame end  837 . Lead wires  185  and  285  connected to each phase of the motor windings  180  and  280  are inserted through the lead wire insertion holes  839 . The lead wires  185  and  285  are taken out from the lead wire insertion holes  839  to the ECU  10 . 
     The ECU  10  includes a control substrate  31 , a power substrate  35 , a heat sink  63 , power modules  160 ,  260  and the like. The cover  465  is formed in a substantially bottomed cylindrical shape and fits radially outward of the rear frame end  837 . The cover  465  is provided so as to cover the substrates  31  and  32  and the power modules  160  and  260 . An opening  466  is provided at the bottom of the cover  465 . 
     The connector  65  has a base portion  651  and a connector portion  652 . The base portion  651  is fixed to the cover  465  by s bolt or the like. The connector portion  652  is taken out axially from the opening  466  of the cover  465 . The front end of the connector portion  652  is opened in the axial direction, and provided to enable a harness (not shown) to be inserted and removed from the side opposite to the motor  80 . The connector portion  652  of the present embodiment is divided into a first connector portion  165  and a second connector portion  265 . The first connector portion  165  is provided with a first connector terminal  166  connected to the first system L 1 , and the second connector portion  265  is provided with a second connector terminal  266  connected to the second system L 2 . The first connector terminal  166  includes a first power supply terminal, a first ground terminal, and a first signal terminal, and the second connector terminal  266  includes a second power supply terminal, a second ground terminal, and a second signal terminal. 
     The control substrate  31  is formed in a substantially rectangular shape, and is fixed to the surface of the heat sink  63  on the motor  80  side with a bolt  319 . The power substrate  35  is formed in a substantially rectangular shape, and is fixed to the surface of the heat sink  63  opposite to the motor  80  by a bolt  329 . The ground pattern of the control substrate  31  is electrically connected to the heat sink  63  via the bolt  319 . Similarly, the ground pattern of the power substrate  35  is electrically connected to the heat sink  63  via the bolt  329 . 
     The heat sink  63  is fixed to the rear frame end  837  and has the same potential as the housing  830 . The heat sink  63  and the rear frame end  837  may be integrated or separate. The heat sink  63  is made of a metal having good thermal conductivity such as aluminum, and power modules  160  and  260  are provided on the side surfaces so as to be able to dissipate heat. That is, in this embodiment, the power modules  160  and  260  are vertically arranged along the axial direction of the motor  80 . 
     The first power module  160  includes switching elements  121  to  126 , motor relays  127  to  129 , and shunt resistors  137  to  139  that constitute the first inverter  120 . The second power module  260  includes switching elements  121  to  126 , motor relays  227  to  229 , and shunt resistors  237  to  239  that constitute the second inverter  220 . Control terminals  161  and  261  connected to the control substrate  31  are respectively provided on the power modules  160  and  260  on the control substrate  31  side. On the power substrate  35  side of the power modules  160  and  260 , power terminals  162  and  262  connected to the power substrate  35  and motor terminals  163  and  263  connected to the lead wires  185  and  285  are provided. The motor terminals  163  and  263  are bent in the direction opposite to the heat sink  63  and connected to the lead wires  185  and  285 . 
       FIG. 3  shows a circuit configuration of the drive device  1 . The ECU  10  includes a first inverter  120 , first motor relays  127  to  129 , first power supply relays  131  and  132 , and a first capacitor  134  and a first coil  135 , which are provided corresponding to the first motor winding  180 . The ECU  10  includes a second inverter  220 , second motor relays  227  to  229 , second power supply relays  231  and  232 , and a second capacitor  234  and a second coil  235 , which are provided corresponding to the second motor winding  280 . 
     The first inverter  120  and the like of the first system L 1  are supplied with electric power from the first battery  199 , and the second inverter  220  and the like of the second system L 2  are supplied with electric power from the second battery  299 . In the present embodiment, the ground is also separated by the first system L 1  and the second system L 2 . The energization of the first motor winding  180  is controlled by a first microcomputer  170 , and the energization of the second motor winding  280  is controlled by a second microcomputer  270 . In other words, in the present embodiment, the first system L 1  and the second system L 2  are provided independently of each other in a completely redundant configuration. 
     The first inverter  120  is a three-phase inverter, and the first switching elements  121  to  126  are connected in a bridge manner. The switching elements  121  to  123  are connected to the high potential side, and the switching elements  124  to  126  are connected to the low potential side. A connection point of the paired U-phase switching elements  121  and  124  is connected to one end of a first U-phase coil  181 . A connection point of the paired V-phase switching elements  122  and  125  is connected to one end of a first V-phase coil  182 . A connection point of the paired W-phase switching elements  123  and  126  is connected to one end of a first W-phase coil  183 . The other ends of the coils  181  to  183  are connected to each other. Shunt resistors  137  to  139 , which are current detection elements for detecting currents flowing in the coils  181  to  183 , are provided on the low potential side of the switching elements  124  to  126 , respectively. 
     The second inverter  220  is a three-phase inverter, and the second switching elements  221  to  226  are bridge-connected. The switching elements  221  to  223  are connected to the high potential side, and the switching elements  224  to  226  are connected to the low potential side. A connection point of the paired U-phase switching elements  221  and  224  is connected to one end of a second U-phase coil  281 . A connection point of the paired V-phase switching elements  222  and  225  is connected to one end of a second V-phase coil  282 . A connection point of the paired W-phase switching elements  223  and  226  is connected to one end of a second W-phase coil  283 . The other ends of the coils  281  to  283  are connected to one another. Shunt resistors  237  to  239 , which are current detection elements for detecting currents flowing in the coils  281  to  283 , are provided on the low potential side of the switching elements  224  to  226 . 
     The first motor relays  127  to  129  are provided between the first inverter  120  and the first motor winding  180 , and are provided to be able to connect and disconnect the first inverter  120  and the first motor winding  180 . The motor relay  127  of the U-phase is provided between the connection point of switching elements  121  and  124  and the U-phase coil  181 , and the motor relay  128  of the V-phase is provided between the connection point of switching elements  122  and  125  and the V-phase coil  182 . The motor relay  129  of the W-phase is provided between the connection point of the switching elements  123  and  126  and the W-phase coil  183 . 
     The second motor relays  227  to  229  are provided between the second inverter  220  and the second motor winding  280 , and are provided to be able to connect and disconnect the second inverter  220  and the second motor winding  280 . The motor relay  227  of the U-phase is provided between the connection point of switching elements  221  and  224  and the U-phase coil  281 . The motor relay  228  of the V-phase is provided between the connection point of switching elements  222  and  225  and the V-phase coil  282 . The motor relay  229  of the W-phase is provided between the connection point of the switching elements  223  and  226  and the W-phase coil  283 . 
     The first power supply relays  131  and  132  are connected in series with each other so that orientations of parasitic diodes are opposite to each other, and are provided between the first battery  199  and the first inverter  120 . The second power supply relays  231  and  232  are connected in series with each other so that orientations of parasitic diodes are opposite to each other, and are provided between the second battery  299  and the second inverter  220 . By connecting the parasitic diodes in the reverse direction, the reverse current is prevented from flowing when the batteries  199  and  299  are mistakenly connected in the reverse direction, and the ECU  10  is protected. 
     In the present embodiment, the switching elements  121  to  126 ,  221  to  226 , the motor relays  127  to  129 ,  227  to  229 , and the power supply relays  131 ,  132 ,  231 , and  232  are all MOSFETs, but may be provided by IGBTs, thyristors, or the like. The power supply relays  131 ,  132 ,  231  and  232  may be mechanical relays. 
     The first switching elements  121  to  126 , the first motor relays  127  to  129 , and the first power supply relays  131  and  132  are turned on and off by a drive signal output from a predriver  176  based on a control signal from the first microcomputer  170 . The second switching elements  221  to  226 , the second motor relays  227  to  229 , and the second power supply relays  231  and  232  are turned on and off by the drive signal output from a predriver  276  based on a control signal from the second microcomputer  270 . As a result, the drive of the motor  80  is controlled by the microcomputers  170  and  270 . In addition, in order to avoid complication, some control lines are omitted in  FIG. 3 . 
     The first capacitor  134  is connected in parallel with the first inverter  120 , and the second capacitor  234  is connected in parallel with the second inverter  220 . The capacitors  134  and  234  are formed of, for example, aluminum electrolytic capacitors. The first coil  135  is provided between the first battery  199  and the first power supply relay  131 , and the second coil  235  is provided between the second battery  299  and the second power supply relay  231 . 
     The first capacitor  134  and the first coil  135 , as well as the second capacitor  234  and the second coil  235 , which form a filter circuit, reduce noise transmitted from other devices sharing the batteries  199  and  299 , and noise transmitted from the drive device  1  to the other devices sharing the batteries  199  and  299 . In addition, the capacitors  134  and  234  store electric charges, thereby assisting a power supply to the inverters  120  and  220 . The power relays  131 ,  132 ,  231  and  232 , the capacitors  134  and  234 , and the coils  135  and  235  are mounted on the power substrate  35 . The power relays  131 ,  132 ,  231  and  232  may be provided in the power modules  160  and  260 . 
     Inter-system ground connection capacitors  41  and  42  connect a first system ground G 1  and a second system ground G 2 . A first electromechanical connection capacitor  142  connects the first system ground G 1  and the housing  830  of the motor  80 . A second electromechanical connection capacitor  242  connects the second system ground G 2  and the housing  830 . The capacitors  41 ,  42 ,  142 , and  242  are, for example, chip capacitors and are mounted on the control substrate  31 . By providing the inter-system ground connection capacitors  41  and  42  and the electromechanical connection capacitors  142  and  242 , a path for feeding back the noise propagated to the motor side to the ECU  10  side is formed, so that the propagation of noise to the outside can be reduced. 
     The microcomputers  170  and  270 , the first integrated circuit unit  175  including the first predriver  176 , the second integrated circuit unit  275  including the second predriver  276 , and the rotation angle sensor  29  (see  FIG. 2 ) are mounted on the control substrate  31 . In this embodiment, the microcomputers  170  and  270  and the rotation angle sensor  29  are mounted on the motor surface  311  which is a surface of the control substrate  31  on the motor  80  side, and the integrated circuit units  175  and  275  are mounted on the anti-motor surface  312  which is a surface of the control substrate  31  on the opposite side of the motor  80 . Further, the microcomputers  170  and  270  perform inter-microcomputer communication via a communication line  45 . 
     Details of the control substrate  31  are shown in  FIGS. 4 to 10 . Hereinafter, the control substrate  31  is simply referred to as a “substrate” as appropriate. In  FIG. 4 , the anti-motor surface  312  of the substrate  31  is shown, and a wiring pattern  321  of the outermost layer on the anti-motor surface  312  side is shown by a broken line. The wiring pattern is mainly described by simplifying the ground pattern. In addition, wiring patterns, vias, resists, mounting parts, etc. are omitted as appropriate. As shown in  FIG. 5 , the control substrate  31  of the present embodiment is a printed circuit board, having a six-layer, on which wiring patterns  321  to  326  are stacked. Further, insulating layers  331  to  335  are formed between the wiring patterns  321  to  326 . 
     Hereinafter, from the anti-motor surface  312  side, the wiring pattern  321  is defined as a first layer, the wiring pattern  322  is defined as a second layer, the wiring pattern  323  is defined as a third layer, the wiring pattern  324  is defined as a fourth layer, the wiring pattern  325  is defined as a fifth layer, and the wiring pattern  326  is defined as a sixth layer. In  FIGS. 6 to 10 , the wiring pattern is shown as a solid line and the outer line of the substrate  31  is shown as a two-dot chain line. Further, in  FIGS. 6 and 9  showing the sixth layer which is the outermost layer on the motor surface  311  side, various electronic components mounted on the motor surface  311  are arranged on the back side of the paper surface, but in order to avoid complication, they are shown by solid lines. 
     As shown in  FIGS. 4 and 5 , the wiring patterns  321  to  326  of each layer are formed a slit  315  that separate a first system area R 1  and a second system area R 2 . The electronic components constituting the first system L 1  are mounted in the first system area R 1 , and the electronic components constituting the second system L 2  are mounted in the second system area R 2 . Specifically, the first microcomputer  170  and the first integrated circuit unit  175  are mounted in the first system area R 1 , and the second microcomputer  270  and the second integrated circuit unit  275  are mounted in the second system area R 2 . Further, the rotation angle sensor  29  is located at a position facing the magnet  875  of the motor surface  311  and is arranged so as to cover the first system area R 1  and the second system area R 2 . In this embodiment, the rotation angle sensor  29  is mounted on the center point of the substrate  31 . The rotation angle sensor  29  is systematized in two systems inside the package. 
       FIG. 6  is an enlarged view of the sixth layer. As shown in  FIG. 6 , a gap GA, which is the width of the slit  315 , is formed to be larger than the minimum pattern gap GB (for example, 0.2 mm) in the control substrate  31 , for example, 1 mm or more. Further, the gap GA is formed larger than the minimum foreign matter size that can be removed in the manufacturing process. This makes it possible to prevent the occurrence of a short circuit between systems due to the entry of conductive foreign matter into the gap GA. Even when some of the wiring other than the slit  315  is short-circuited due to a conductive foreign matter or the like, if the other system is normal, the control in the other system can be continued and the simultaneous failure of the two systems can be avoided. 
     As shown in  FIG. 5 , the slit  315  is formed at the same position when projected from one of the motor surface  311  and the anti-motor surface  312  to the other, and, in the gap projection area, a planar pattern such as a ground pattern is not formed. For example, when the wiring pattern is continuously cut out in the slit  315 , the wiring pattern of another layer may be formed in the cutout portion. 
       FIG. 7  shows the wiring pattern  323  in the third layer,  FIG. 8  shows the wiring pattern  325  in the fifth layer, and  FIG. 9  shows the wiring pattern  326  in the sixth layer. The first microcomputer  170  mounted in the first system area R 1  and the second microcomputer  270  mounted in the second system area R 2  perform inter-microcomputer communication on the communication line  45 . The communication line  45  between the microcomputers is composed of patterns P 16 , P 26 , and P 36  formed in the wiring pattern  326 , patterns P 25  and P 35  formed in the wiring pattern  325 , and a pattern P 23  formed in the wiring pattern  323 . The information from the first microcomputer  170  is output to the second microcomputer  270  via the patterns P 16 , P 35 , P 23 , P 25 , and P 26 . The information of the second microcomputer  270  is output to the first microcomputer  170  in the reverse order. Further, the microcomputers  170  and  270  can communicate with each other via the pattern P 36  and other elements. 
       FIG. 10  is a superposed view in which the wiring patterns  325  and  326  are overlapped, is a view seen from the motor surface  311  side, and is inverted for the sake of explanation. As shown in  FIG. 10 , in the present embodiment, the pattern P 35  formed on the fifth layer and the pattern P 36  formed on the sixth layer cover the slit  315 , and connects the first system area R 1  and the second system area R 2 . Further, the pattern P 35  and the pattern P 36  intersect on the slit  315 . In other words, the pattern P 36  connects the systems at a location overlapping the pattern P 35  when projected from one of the motor surface  311  and the anti-motor surface  312  onto the other. 
     The inter-system ground connection capacitor  41  is arranged adjacent to the pattern P 36 . Further, the inter-system ground connection capacitor  42  is arranged adjacent to the inter-system ground connection capacitor  41 . In other words, one inter-system ground connection capacitor  41  is arranged between the pattern P 36  and the other inter-system ground connection capacitor  42 . Here, “arranged adjacent to” means that they are arranged in a state where no other electronic component is provided therebetween. In the present embodiment, the capacitor  42  has a larger capacity than the capacitor  41 , but the capacities may be the same, and can be arbitrarily designed according to the mounting space, the required capacity, and the like. 
     Further, the inter-system ground connection capacitors  41  and  42  are arranged at locations overlapping the pattern P 35  when projected from one of the motor surface  311  and the anti-motor surface  312  to the other. In the present embodiment, among the wiring patterns constituting the communication line  45 , the pattern P 35  and the pattern P 36  connecting between the systems are arranged so as to overlap with each other by the slit  315 , and the inter-system ground connection capacitors  41  and  42  are arranged at a part at which the pattern P 35  and the pattern P 36  intersect with each other. This configuration makes it possible to reduce communication noise. 
     As described above, the ECU  10  includes a plurality of systems of drive control components and the substrate  31 . The drive control component can independently control the motor  80  as a control target for each system. In the present embodiment, the drive control component includes the microcomputers  170  and  270  and the integrated circuit units  175  and  275 . Here, “the control target can be controlled independently for each system” is not limited to the case where each system is configured in the same manner. As long as the motor  80  can be driven by one system, specification and the like of each system may be different, for example, when one of the systems is normally used and the other system is used for backup, the system for backup is simplified compared to the system normally sued. 
     The drive control components are mounted on the substrate  31  by dividing the area for each system, and the slit  315  for separating the system areas R 1  and R 2  is formed in each of the wiring patterns  321  to  326  of the plurality of layers. The gap GA, which is the width of the slit  315 , is formed larger than the minimum pattern gap GB in the substrate  31 . 
     Further, the slit  315  is formed at the same position in all layers when projected from one side to the other side of the motor surface  311  and the anti-motor surface  312 , which are the two main surfaces of the substrate  31 . Here, the term “same position” means that a manufacturing error is allowed, and when a notch or the like continuous with the slit  315  is formed in the pattern, the notch or the like may be different between the layers. As a result, it is possible to suppress the occurrence of a short circuit between systems due to conductive foreign matter, ion migration, or the like, and thus it is possible to reduce the probability of simultaneous failure of a plurality of systems. 
     The microcomputers  170  and  270  can communicate with each other between the systems, and the wiring pattern constituting the communication line  45  between the microcomputers used for the inter-microcomputer communication crosses the slit  315  and connects the system areas R 1  and R 2 . As a result, the microcomputers  170  and  270  can appropriately perform the inter-microcomputer communication. 
     The cross pattern, which is a wiring pattern that crosses the slit  315 , is separated in the outermost layer and the inner layer of the substrate  31 . Further, the pattern P 36  which is the cross pattern of the outermost layer and the pattern P 35  which is the cross pattern of the inner layer intersect with each other at a position where the slit  315  is formed when projected from one side to the other side of the motor surface  311  and the anti-motor surface  312  which are the two main surfaces of the substrate  31 . As a result, the mounting area of the substrate  31  can be used with high efficiency as compared with the case where all the cross patterns are provided in the outermost layer, for example. 
     The ECU  10  includes the inter-system ground connection capacitors  41  and  42  that connects the ground patterns each corresponding to one of the systems and separated with each other. The inter-system ground connection capacitors  41  and  42  are mounted adjacently to the cross portion where the pattern P 35  and the pattern P 36  cross with each other. Since the inter-system ground connection capacitors  41  and  42  are mounted at adjacently to the crossing portion, communication noise can be reduced. 
     In this embodiment, the ECU  10  corresponds to an “electronic control device”, the motor  80  corresponds to a “control target”, the areas R 1  and R 2  correspond to “system areas”, the control substrate  31  corresponds to a “substrate”, and the motor surface  311  and the anti-motor surface  312  corresponds to “main surfaces”. Further, the patterns P 35  and P 36  correspond to a “cross pattern”, the sixth layer on which the pattern P 36  is formed corresponds to an “outermost layer”, and the fifth layer on which the pattern P 35  is formed corresponds to an “inner layer”. 
     Other Embodiments 
     In the above embodiment, the control substrate  31  has been mainly described. In other embodiments, electronic components such as electrolytic capacitors mounted on the power substrate  35  may be regarded as “drive control components”, and the power substrate  35  may have a slit that separates system areas similarly to the control substrate  31 . In the above embodiment, the switching element, the motor relay, and the shunt resistor are vertically arranged as power modules. In other embodiments, at least a part of the switching element, the motor relay and the shunt resistor may be mounted on the substrate. Further, these electronic components surface-mounted on the substrate may be regarded as “drive control components” and mounted by dividing the area for each system. 
     In the above embodiment, the power substrate and the control substrate are provided. In other embodiments, the number of substrates may be one or three or more. In the above embodiment, the substrate is a 6-layer substrate. In other embodiments, the number of layers of the substrate may be other than 6 layers, for example, 4 layers. Further, the substrate of the above embodiment is substantially rectangular. In other embodiments, the shape of the substrate may be other than rectangular, such as, such as a circular substrate. 
     In the above embodiment, the wiring pattern constituting the communication line between microcomputers crosses the slit. In other embodiments, when it is necessary to perform transmission and reception of information between systems other than the inter-microcomputer communication, a wiring pattern other than the communication line for microcomputers may cross the slit. In the above embodiment, the communication lines between the microcomputers are separately provided in the outermost layer and the inner layer. In other embodiments, the communication line between microcomputers may be provided in one layer. In the above embodiment, the cross pattern is provided on the outermost layer, the sixth layer, and the inner layer, the fifth layer. In other embodiments, the outermost layer may be the first layer, and the inner layer may be any of the second layer to the fourth layer. 
     In the above embodiment, the two inter-system ground connection capacitors are provided. In other embodiments, the number of inter-system ground connection capacitors may be one or three or more. In the above embodiment, the inter-system ground connection capacitor is provided adjacently to the crossing position of the cross pattern. In other embodiments, the inter-system ground connection capacitor may be provided at a position other than adjacent to the cross position of the cross pattern. 
     In the above embodiment, two sets of motor windings are provided, and the number of systems is two. In other embodiments, the number of systems may be three or more. Further, for example, one control circuit may be provided for a plurality of motor windings and a plurality of inverter circuits. A plurality of inverter circuits and a plurality of motor windings may be provided for one control circuit. That is, the numbers of the motor windings, inverter circuits and control circuits may be different. Further, the number of motor windings and power supplies may be one. 
     In the above-described embodiments, the motor is a three-phase brushless motor. In other embodiments, the motor is not limited to the three-phase brushless motor, and any motor may be used. Further, the motor may also be a generator, or may be a motor-generator having both of a motor function and a generator function, i.e., not necessarily be limited to the rotating electric machine. Further, in the above embodiment, the control target is a motor. In other embodiments, the control target may be other than the motor. 
     In the above embodiments, the electronic control unit is applied to the electric power steering device. In other embodiments, the electronic control unit may be applied to other apparatuses different from the electric power steering device. As described above, the present disclosure is not limited to the embodiments described above, and can be implemented in various forms without departing from the spirit of the present disclosure. 
     The present disclosure has been described in accordance with the embodiments. However, the present disclosure is not limited to such embodiments and structures. The present disclosure also encompasses various modifications and variations within the scope of equivalents. Furthermore, various combination and formation, and other combination and formation including one, more than one or less than one element may be made in the present disclosure.