Electronic control device and electric power steering device

Abstract

An electronic control device according to the present invention includes: a wiring substrate having a first semiconductor package including an upper arm-side switching element and a first sealing member; a second semiconductor package having a lower arm-side switching element and a second sealing member; a third semiconductor package having a switching element for a motor relay and a third sealing member; and a CPU, the first semiconductor package, the second semiconductor package, and the third semiconductor package are mounted on a first surface of the wiring substrate, the upper arm-side switching element, the lower arm-side switching element, and the motor relay switching element form an inverter circuit capable of supplying current to the motor, and the upper arm-side switching element, the lower arm-side switching element, and the motor relay switching element form an inverter circuit capable of supplying current to the motor in a plan view from a thickness direction of the wiring substrate. An area of the first semiconductor package is smaller than an area of the third semiconductor package, and an area of the second semiconductor package is smaller than an area of the third semiconductor package.

Description

Technical Field

[0001] The present disclosure relates to an electronic control device and an electric power steering device. Background Art

[0002] Patent Document 1 discloses a wiring board used in an electronic control device for controlling a motor. A plurality of switching elements, control elements, etc. for supplying current to the motor are mounted on the wiring board. Prior Art Documents Patent Documents

[0003] Patent Document 1: Japanese Patent Application Laid-Open No. 2020-4887 Summary of the Invention Technical Problem to be Solved by the Invention

[0004] Since a large number of switching elements are used in the electronic control device, the installation area of the switching elements occupies a relatively large proportion of the total area of the wiring board. When the installation area of the switching elements increases, the size of the wiring board becomes larger. There is room for improvement in miniaturizing the wiring board by reducing the installation area of the switching elements.

[0005] In view of the above circumstances, an object of the present disclosure is to provide an electronic control device and an electric power steering device capable of miniaturizing the wiring board. Technical Means for Solving the Technical Problem

[0006] One aspect of the electronic control device according to the present disclosure is an electronic control device for controlling a motor, the electronic control device including: a wiring board having a first surface and a second surface on the opposite side of the first surface; a first semiconductor package having an upper-arm-side switching element and a first sealing member surrounding the upper-arm-side switching element; a second semiconductor package having a lower-arm-side switching element and a second sealing member surrounding the lower-arm-side switching element; a third semiconductor package having a motor-relay-use switching element and a third sealing member surrounding the motor-relay-use switching element; and a CPU that controls the upper-arm-side switching element, the lower-arm-side switching element, and the motor-relay-use switching element, the first semiconductor package, the second semiconductor package, and the third semiconductor package are mounted on the first surface of the wiring board, the upper-arm-side switching element, the lower-arm-side switching element, and the motor-relay-use switching element form an inverter circuit capable of supplying current to the motor, when viewed from above in the thickness direction of the wiring board, the area of the first semiconductor package is smaller than the area of the third semiconductor package, and the area of the second semiconductor package is smaller than the area of the third semiconductor package.

[0007] One aspect of the electric power steering apparatus according to the present disclosure includes the electronic control unit; and the motor controlled by the electronic control unit. Advantageous Effects of the Invention

[0008] According to the present disclosure, an electronic control unit and an electric power steering apparatus capable of miniaturizing a wiring board can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 is a circuit diagram of the electronic control unit and the electric power steering apparatus according to Embodiment 1. Figure 2 is a cross-sectional view showing the structure of the electronic control unit and the electric power steering apparatus according to Embodiment 1. Figure 3 is a top view of the wiring board according to Embodiment 1. Figure 4 is a cross-sectional view showing the heat dissipation structure of the semiconductor package according to Embodiment 1. Figure 5 is a circuit diagram of the electronic control unit and the electric power steering apparatus according to Embodiment 2. Figure 6 is a top view of the wiring board according to Embodiment 2. Figure 7 is a circuit diagram of the electronic control unit and the electric power steering apparatus according to Embodiment 3. Figure 8 is a top view of the wiring board according to Embodiment 3. Figure 9 is a top view of the wiring board according to Modification 1 of Embodiment 3. Figure 10 is a circuit diagram of the electronic control unit and the electric power steering apparatus according to Modification 2 of Embodiment 3. Figure 11 is a circuit diagram of the electronic control unit and the electric power steering apparatus according to Embodiment 4. Figure 12 is a top view of the wiring board according to Embodiment 4. Figure 13 is a top view of the wiring board according to the modification of Embodiment 4. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0010] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. The scope of the present disclosure is not limited to the following embodiments, and can be arbitrarily changed within the technical idea of the present disclosure.

[0011] Embodiment 1. Figure 1 This is the circuit diagram of the electronic control device 1 and the electric power steering device 100 in Embodiment 1. Figure 2 This is a cross-sectional view of the electronic control device 1 and the electric power steering device 100. As Figure 1 shown, the electric power steering device 100 includes an electronic control device 1 and a motor 2. The electric power steering device 100 is configured to use the torque generated by the motor 2 as an assist torque when the vehicle steers. Although detailed description is omitted, the rotating shaft 43 of the motor 2 is connected to the steering system of the vehicle via a speed reducer or the like. The electronic control device 1 controls the motor 2.

[0012] As Figure 1 shown, the electronic control device 1 includes an inverter circuit 3, a control circuit 4, a rotation sensor 14, etc. The control circuit 4 includes a CPU 10, a FET drive circuit 11, an input circuit 12, a power supply circuit 13, etc.

[0013] As Figure 2 shown, the electronic control device 1 includes a wiring board 20. The inverter circuit 3, the control circuit 4, the rotation sensor 14, etc. are mounted on the wiring board 20. The wiring board 20 has a first surface 20a and a second surface 20b. The wiring board 20 is covered by a cover portion 21.

[0014] As Figure 2 shown, the motor 2 includes a motor body 40, a frame 45, a housing 46, a terminal group 44, etc. For example, a brushless DC motor can be used as the motor 2. The motor 2 in this embodiment is a three-phase brushless motor. The three phases are the U phase, the V phase, and the W phase.

[0015] The motor body 40 includes a stator 41 and a rotor 42. The stator 41 has a three-phase winding (three-phase coil). In Figure 1 , the three-phase winding is denoted by reference numerals Ua, Va, and Wa. The windings Ua, Va, and Wa are delta-connected. The windings Ua, Va, and Wa can also be star-connected. The rotor 42 has a rotating shaft 43. The rotating shaft 43 rotates relative to the stator 41 about the motor shaft C.

[0016] (Direction definition) In this specification, the direction along the motor shaft C is referred to as the axial direction. The axial direction also coincides with the thickness direction of the wiring board 20. As Figure 2As shown, the wiring substrate 20 and the rotor 42 are arranged side by side in the axial direction. In the axial direction, the side where the wiring substrate 20 is arranged is called the upper side, and the side where the rotor 42 is arranged is called the lower side. The wiring substrate 20 extends so as to cross (substantially orthogonally) in the axial direction. In the wiring substrate 20, the first surface 20a is the surface facing upward, and the second surface 20b is the surface facing downward. That is, the first surface 20a faces the cover portion 21 side, and the second surface 20b faces the rotor 42 side. Observation from the axial direction is called a plan view. The view observed from the axial direction is called a top view. In addition, the axial direction may not coincide with the vertical direction.

[0017] As Figure 2 shown, the frame 45 is cylindrical. The motor main body 40 is accommodated inside the frame 45. A through hole is formed at the center of the bottom of the frame 45, and the lower bearing 47b is fixed inside the through hole. The lower end portion of the rotating shaft 43 is inserted into the lower bearing 47b.

[0018] The housing 46 is provided on the upper part of the motor 2. The housing 46 is fitted inside the upper end portion of the cylindrical frame 45. The housing 46 prevents foreign matters from entering the inside of the motor 2. A through hole is formed at the center of the housing 46, and the upper bearing 47a is fixed inside the through hole. The upper end portion of the rotating shaft 43 is inserted into the upper bearing 47a.

[0019] The upper bearing 47a and the lower bearing 47b hold the rotating shaft 43 so that the rotating shaft 43 can rotate smoothly. The sensor magnet 48 is mounted at the upper end of the rotating shaft 43. The sensor magnet 48 has at least one or more N poles and S poles respectively.

[0020] As Figure 2 shown, the wiring substrate 20 is arranged above the housing 46. The stator 41 (three-phase windings Ua, Va, Wa) is arranged below the housing 46. The terminal group 44 electrically connects the wiring substrate 20 and the three-phase windings Ua, Va, Wa. Specifically, the housing 46 has a through hole extending in the axial direction. The terminal group 44 is inserted into the through hole of the housing 46. The terminal group 44 includes three terminals corresponding to the three-phase windings Ua, Va, Wa respectively.

[0021] As Figure 3 shown, three current supply holes 22 are formed in the wiring substrate 20. The three terminals included in the terminal group 44 are respectively inserted into these three current supply holes 22. Current is supplied from the inverter circuit 3 of the wiring substrate 20 to the three-phase windings Ua, Va, Wa via the current supply holes 22 and the terminal group 44. Thereby, the rotating shaft 43 rotates. In addition, the three terminals included in the terminal group 44 may be the ends of the three-phase windings Ua, Va, Wa, or relay members electrically connected to the ends of the three-phase windings Ua, Va, Wa.

[0022] The rotation sensor 14 detects the rotation angle of the rotating shaft 43. As the rotation sensor 14, an MR (magnetoresistance) sensor can be used. The rotation sensor 14 detects the rotation angle of the rotating shaft 43 by detecting the magnetic field generated by the sensor magnet 48. The rotation sensor 14 is configured to face the sensor magnet 48. More specifically, as Figure 2 shown, the rotation sensor 14 is mounted on the second surface 20b of the wiring substrate 20. Further, in a plan view, the rotation sensor 14 is arranged at a position overlapping with the sensor magnet 48. By configuring in this way, the detection accuracy of the rotation angle based on the rotation sensor 14 can be improved, and the controllability of the electronic control device 1 over the motor 2 can be improved. However, as long as the desired detection accuracy can be obtained, the rotation sensor 14 may be arranged on the first surface 20a of the wiring substrate 20. Alternatively, the rotation sensor 14 may be arranged at a position offset from the sensor magnet 48 in a plan view.

[0023] As Figure 2 shown, the connector assembly 50 is arranged above the cover portion 21. The connector assembly 50 is a component in which a connector, a metal bus bar, terminals, etc., and a holding member 51 for holding them are integrally formed. The holding member 51 is made of resin, for example. The connector assembly 50 connects the power supply line L1 and the ground line L2 required for controlling the motor 2 and driving the motor 2 to the wiring substrate 20. Further, the connector assembly 50 connects a signal transmission line for transmitting signals such as a torque sensor signal and a vehicle communication signal to the wiring substrate 20. The connector assembly 50 may electrically connect the power supply line L1, the ground line L2, the signal transmission line, etc. to the electronic control device 1 all at once. Alternatively, a connector different from the connector assembly 50 may be provided for connecting the power supply line L1, the ground line L2, etc.

[0024] The connector assembly 50 includes a plurality of connector terminals 52 extending downward from the holding member 51. The plurality of connector terminals 52 are respectively inserted into a plurality of connector through-holes 23 formed in the wiring substrate 20 (refer to Figure 3 ). Further, each connector terminal 52 is electrically connected to a circuit pattern formed on the wiring substrate 20.

[0025] The wiring substrate 20 is fixed to the housing 46 by screws or the like. The wiring substrate 20 may be fixed to the cover portion 21, or the connector assembly 50, etc.

[0026] Next, an outline of the operation of each part of the electronic control device 1 will be described. The power supply circuit 13 uses the power supplied from the battery 9 (power supply) to generate a power supply voltage for enabling each electronic component (CPU 10, FET drive circuit 11, input circuit 12, rotation sensor 14, etc.) constituting the electronic control device 1 to operate normally.

[0027] The input circuit 12 inputs various information received by the electronic control unit 1 from the sensor group 8, the rotation sensor 14, etc. into the CPU 10. Although not shown in the figure, the input circuit 12 includes a torque sensor interface circuit and a vehicle communication interface circuit. The torque sensor interface circuit is a circuit for detecting the driver's steering torque in the electric power steering device 100 and obtaining information on the steering torque. The vehicle communication interface circuit is a circuit for receiving various information from the vehicle system.

[0028] Based on the above various information input from the input circuit 12, etc., the CPU 10 calculates a control amount for supplying power to the motor 2. The FET drive circuit 11 drives the inverter circuit 3 based on the calculation result of the CPU 10.

[0029] The inverter circuit 3 supplies power to the three-phase windings Ua, Va, Wa of the motor 2 based on the calculation result of the CPU 10. The inverter circuit 3 has three upper arms and three lower arms corresponding to each of the U phase, V phase, and W phase. In the inverter circuit 3, the respective circuit configurations related to the U phase, V phase, and W phase are the same. Therefore, the U phase will be described below as a representative of these three phases. That is, the following description equally applies to the V phase and W phase. In addition, Figure 1 The components corresponding to the U phase in the components of the inverter circuit 3 are shown. However, in reality, the inverter circuit 3 also includes components corresponding to the V phase and W phase. In other words, in Figure 1 , the components corresponding to the V phase and W phase included in the inverter circuit 3 are omitted.

[0030] As Figure 1As shown, the inverter circuit 3 includes a smoothing capacitor 30u, an upper-arm-side switching element 31au, a lower-arm-side switching element 32au, a motor-relay switching element 33au, and a shunt resistor 34u. The upper-arm-side switching element 31au is arranged on the upper arm, and the lower-arm-side switching element 32au is arranged on the lower arm. The upper-arm-side switching element 31au is electrically connected to the positive electrode of the battery 9, and the lower-arm-side switching element 32au is electrically connected to the negative electrode of the battery 9. The upper-arm-side switching element 31au and the lower-arm-side switching element 32au are connected in series. The motor-relay switching element 33au is connected between the upper-arm-side switching element 31au and the lower-arm-side switching element 32au. The motor-relay switching element 33au has a relay function. That is, the motor-relay switching element 33au switches the opening and closing of the power supply from the part between the upper-arm-side switching element 31au and the lower-arm-side switching element 32au to the winding Ua of the motor 2. The upper-arm-side switching element 31au and the lower-arm-side switching element 32au are operated by the FET drive circuit 11 based on the operation result of the CPU 10. As an example of the upper-arm-side switching element 31au, the lower-arm-side switching element 32au, and the motor-relay switching element 33au, an FET (Field Effect Transistor) can be adopted.

[0031] The smoothing capacitor 30u is connected near the upper-arm-side switching element 31au and the lower-arm-side switching element 32au. The smoothing capacitor 30u has a function of suppressing the power supply voltage fluctuation and noise during switching. The shunt resistor 34u is connected between the lower-arm-side switching element 32au and the ground. The shunt resistor 34u is used to detect the drive current flowing through the winding Ua of the motor 2. In addition, the inverter circuit 3 may include a choke coil that suppresses the emission of noise to the outside of the electronic control device 1 and suppresses the inflow of noise into the electronic control device 1.

[0032] Next, the arrangement of each component included in the electronic control device 1 will be described. Figure 3 is a top view showing the schematic shape of the wiring board 20 and the arrangement of the components mounted on the wiring board 20. In addition, Figure 3 is a view of the wiring board 20 observed from the first surface 20a side. The components mounted on the first surface 20a are represented by solid lines, and the components mounted on the second surface 20b are represented by dashed lines. As Figure 3 shown, the CPU 10 and the power supply circuit 13 are mounted on the first surface 20a of the wiring board 20. The FET drive circuit 11 is mounted on the second surface 20b of the wiring board 20. In addition, the CPU 10 may also be mounted on the second surface 20b.

[0033] Three first semiconductor packages 31u, 31v, and 31w corresponding to each of the U-phase, V-phase, and W-phase, three second semiconductor packages 32u, 32v, and 32w, and three third semiconductor packages 33u, 33v, and 33w are mounted on the first surface 20a of the wiring substrate 20. The three first semiconductor packages 31u, 31v, and 31w have the same structure. The three second semiconductor packages 32u, 32v, and 32w have the same structure. The three third semiconductor packages 33u, 33v, and 33w have the same structure. Therefore, the U-phase will be described below to represent these three phases. That is, the following description also applies equally to the V-phase and W-phase.

[0034] The first semiconductor package 31u includes an upper arm side switching element 31au and a first sealing member 31bu surrounding the upper arm side switching element 31au. The outer shape of the first semiconductor package 31u (the first sealing member 31bu) is rectangular when viewed from above. The first sealing member 31bu is made of resin, for example. The second semiconductor package 32u includes a lower arm side switching element 32au and a second sealing member 32bu surrounding the lower arm side switching element 32au. The outer shape of the second semiconductor package 32u (the second sealing member 32bu) is rectangular when viewed from above. The second sealing member 32bu is made of resin, for example. The third semiconductor package 33u includes a motor relay switching element 33au and a third sealing member 33bu surrounding the motor relay switching element 33au. The outer shape of the third semiconductor package 33u (the third sealing member 33bu) is rectangular when viewed from above. The third sealing member 33bu is made of resin, for example.

[0035] When viewed from above, the area of the first semiconductor package 31u is smaller than the area of the third semiconductor package 33u, and the area of the second semiconductor package 32u is smaller than the area of the third semiconductor package 33u. When viewed from above, the area of the first semiconductor package 31u is the same as the area of the second semiconductor package 32u. Similarly for the V-phase, when viewed from above, the area of the first semiconductor package 31v is smaller than the area of the third semiconductor package 33v, and the area of the second semiconductor package 32v is smaller than the area of the third semiconductor package 33v. When viewed from above, the area of the first semiconductor package 31v is the same as the area of the second semiconductor package 32v. Similarly for the W-phase, when viewed from above, the area of the first semiconductor package 31w is smaller than the area of the third semiconductor package 33w, and the area of the second semiconductor package 32w is smaller than the area of the third semiconductor package 33w. When viewed from above, the area of the first semiconductor package 31w is the same as the area of the second semiconductor package 32w. According to such a structure, compared with the case where the areas of the first semiconductor packages 31u, 31v, 31w and the second semiconductor packages 32u, 32v, 32w are the same as the areas of the third semiconductor packages 33u, 33v, 33w, the mounting areas of the switching elements 31au, 31av, 31aw, 32au, 32av, 32aw, 33au, 33av, 33aw in the wiring substrate 20 can be reduced.

[0036] In addition, three shunt resistors 34u, 34v, 34w corresponding to each of the U-phase, V-phase, and W-phase are mounted on the first surface 20a of the wiring substrate 20. The three shunt resistors 34u, 34v, 34w have the same structure.

[0037] Here, the upper-arm side switching elements 31au, 31av, 31aw, the lower-arm side switching elements 32au, 32av, 32aw, the motor relay switching elements 33au, 33av, 33aw, and the smoothing capacitors 30u, 30v, 30w, etc. are heating elements that generate heat when a large current is applied. The heat generated by these heating elements is preferably released to the outside of the electric power steering device 100.

[0038] Hereinafter, the first semiconductor packages 31u, 31v, 31w, the second semiconductor packages 32u, 32v, 32w, and the third semiconductor packages 33u, 33v, 33w are also collectively referred to as "semiconductor packages P". As Figure 4 shown, the electric power steering device 100 according to the first embodiment has a heat dissipation structure that dissipates the heat generated by each semiconductor package P to the housing 46. More specifically, the housing 46 is arranged to face the second surface 20b of the wiring substrate 20. An axial gap is formed between the wiring substrate 20 and the housing 46, and a thermal connection member 24 is provided in this gap. The thermal connection member 24 thermally connects the wiring substrate 20 and the housing 46. The thermal connection member 24 has insulation and high thermal conductivity. The thermal connection member 24 is, for example, thermal grease. By providing the thermal connection member 24, the heat generated from each semiconductor package P can be effectively transferred to the housing 46 via the thermal connection member 24.

[0039] In addition, a metal thermal conduction member 25 is provided on the wiring substrate 20 and is arranged to penetrate from the first surface 20a to the second surface 20b. In Figure 4In the example, the heat conduction member 25 is a thermal via. The heat conduction member 25 can be a copper inlay. The upper heat dissipation pattern 26a is formed on the first surface 20a of the wiring substrate 20. The lower heat dissipation pattern 26b is formed on the second surface 20b of the wiring substrate 20. The upper end of the heat conduction member 25 is connected to the upper heat dissipation pattern 26a, and the lower end is connected to the lower heat dissipation pattern 26b. The heat conduction member 25 is thermally connected to the semiconductor package P via the upper heat dissipation pattern 26a. The heat conduction member 25 is thermally connected to the heat connection member 24 via the lower heat dissipation pattern 26b. According to such a structure, the heat of the semiconductor package P can be transferred to the lower heat dissipation pattern 26b via the upper heat dissipation pattern 26a and the heat conduction member 25. In addition, the heat can be transferred from the lower heat dissipation pattern 26b to the housing 46 via the heat connection member 24.

[0040] As described above, in a plan view, the areas of the first semiconductor packages 31u, 31v, 31w are smaller than the areas of the third semiconductor packages 33u, 33v, 33w, and the areas of the second semiconductor packages 32u, 32v, 32w are smaller than the areas of the third semiconductor packages 33u, 33v, 33w. Therefore, the heat dissipation performance of the first semiconductor packages 31u, 31v, 31w and the second semiconductor packages 32u, 32v, 32w is lower than that of the third semiconductor packages 33u, 33v, 33w. Here, the heat generation amounts of the upper-arm side switching elements 31au, 31av, 31aw, the lower-arm side switching elements 32au, 32av, 32aw, and the motor relay switching elements 33au, 33av, 33aw will be described taking the U phase as an example. The following description also applies to the V phase and the W phase. Regarding the operation of the PWM drive of the motor 2, when the upper-arm side switching element 31au is turned on, current flows in the path from the power supply line L1 to the upper-arm side switching element 31au, the motor relay switching element 33au, the motor 2, and the arms of other phases. When the lower-arm side switching element 32au is turned on, current flows in the path from the ground line L2 to the shunt resistor 34u, the lower-arm side switching element 32au, the motor relay switching element 33au, the motor 2, and the arms of other phases. That is, for the time during which current flows through each switching element in each cycle of the PWM drive of the motor 2, the time of the upper-arm side switching element 31au and the lower-arm side switching element 32au is shorter than that of the motor relay switching element 33au. Therefore, for the heat generation amount of each switching element, the heat generation amounts of the upper-arm side switching element 31au and the lower-arm side switching element 32au are smaller than that of the motor relay switching element 33au. Based on the above, the areas of the first semiconductor packages 31u, 31v, 31w and the second semiconductor packages 32u, 32v, 32w are smaller than the areas of the third semiconductor packages 33u, 33v, 33w. Thus, by maintaining the balance between the heat generation amount and the heat dissipation performance in each semiconductor package, it is possible to uniformly suppress the temperature rise in the first semiconductor packages 31u, 31v, 31w, the second semiconductor packages 32u, 32v, 32w, and the third semiconductor packages 33u, 33v, 33w. That is, it is possible to prevent heat from locally concentrating in the electronic control device 1 and uniformly suppress the temperature rise of each component of the electronic control device 1. Therefore, it is possible to suppress the performance degradation of the electric power steering device 100 caused by the heat generation of the components, thereby improving the driving ability of the electric power steering device 100.

[0041] As described above, the electronic control device 1 of the present embodiment includes a wiring substrate 20, first semiconductor packages 31u, 31v, 31w, second semiconductor packages 32u, 32v, 32w, third semiconductor packages 33u, 33v, 33w, and a CPU 10. The first semiconductor packages 31u, 31v, 31w include upper arm side switching elements 31au, 31av, 31aw, and first sealing members 31bu, 31bv, 31bw surrounding the upper arm side switching elements 31au, 31av, 31aw. The second semiconductor packages 32u, 32v, 32w include lower arm side switching elements 32au, 32av, 32aw, and second sealing members 32bu, 32bv, 32bw surrounding the lower arm side switching elements 32au, 32av, 32aw. The third semiconductor packages 33u, 33v, 33w include motor relay switching elements 33au, 33av, 33aw, and third sealing members 33bu, 33bv, 33bw surrounding the motor relay switching elements 33au, 33av, 33aw. The CPU 10 controls the upper arm side switching elements 31au, 31av, 31aw, the lower arm side switching elements 32au, 32av, 32aw, and the motor relay switching elements 33au, 33av, 33aw. The first semiconductor packages 31u, 31v, 31w, the second semiconductor packages 32u, 32v, 32w, and the third semiconductor packages 33u, 33v, 33w are mounted on the first surface 20a of the wiring substrate 20. The upper arm side switching elements 31au, 31av, 31aw, the lower arm side switching elements 32au, 32av, 32aw, and the motor relay switching elements 33au, 33av, 33aw form an inverter circuit 3 capable of supplying power to the motor 2. When viewed from above in the thickness direction of the wiring substrate 20, the area of the first semiconductor packages 31u, 31v, 31w is smaller than the area of the third semiconductor packages 33u, 33v, 33w, and the area of the second semiconductor packages 32u, 32v, 32w is smaller than the area of the third semiconductor packages 33u, 33v, 33w. In addition, the electric power steering device 100 of the present embodiment includes the electronic control device 1 and a motor 2 controlled by the electronic control device 1. With such a structure, the mounting area of the switching elements 31au, 31av, 31aw, 32au, 32av, 32aw, 33au, 33av, 33aw in the wiring substrate 20 can be reduced, thereby achieving miniaturization of the wiring substrate 20.

[0042] In addition, the electric motor 2 includes a motor main body 40, a cylindrical frame 45 that houses the motor main body 40, and a housing 46 that fits onto the frame 45. The housing 46 is configured to face the second surface 20b of the wiring substrate 20. A thermal connection member 24 for thermally connecting the housing 46 and the wiring substrate 20 is provided between the housing 46 and the wiring substrate 20. A heat conduction member 25 is disposed on the wiring substrate 20 and is configured to penetrate from the first surface 20a to the second surface 20b and is thermally connected to the thermal connection member 24. Accordingly, heat generated by the first semiconductor packages 31u, 31v, 31w, the second semiconductor packages 32u, 32v, 32w, and the third semiconductor packages 33u, 33v, 33w mounted on the first surface 20a of the wiring substrate 20 can be dissipated to the housing 46 via the heat conduction member 25 and the thermal connection member 24.

[0043] Embodiment 2. Next, an electric power steering apparatus according to Embodiment 2 will be described. The basic structure of the electric power steering apparatus according to this embodiment is the same as that of the electric power steering apparatus of Embodiment 1, and thus the description will focus on the differences.

[0044] As Figure 5 shown, in this embodiment, the electric motor 2 has two sets of three-phase windings (three-phase coils). Specifically, in addition to the first three-phase windings Ua, Va, Wa, the electric motor 2 further includes second three-phase windings Ub, Vb, Wb. The windings Ub, Vb, Wb are connected in a delta configuration. The windings Ub, Vb, Wb may also be connected in a star configuration. In addition, the electronic control unit 1 further includes a second inverter circuit 5 that supplies power to the second three-phase windings Ub, Vb, Wb, and a second FET drive circuit 15 that drives the second inverter circuit 5. Additionally, in Figure 5 the example, the inverter circuit 3 and the second inverter circuit 5 are connected to a common battery 9 and ground. However, the second inverter circuit 5 may be connected to a battery and ground of another system.

[0045] The terminal group 44 of the electric motor 2 includes, in addition to three terminals respectively corresponding to the first three-phase windings Ua, Va, Wa, three second terminals respectively corresponding to the second three-phase windings Ub, Vb, Wb. As Figure 6 shown, in the wiring substrate 20, in addition to the three current supply holes 22, three second current supply holes 28 are formed. The three second terminals included in the terminal group 44 are respectively inserted into the three current supply holes 28. Current is supplied from the inverter circuit 3 to the three-phase windings Ua, Va, Wa via the current supply holes 22 and the terminal group 44, and current is supplied from the second inverter circuit 5 to the second three-phase windings Ub, Vb, Wb via the second current supply holes 28 and the terminal group 44.

[0046] The circuit structure of the second inverter circuit 5 is the same as that of the inverter circuit 3. That is, the second inverter circuit 5 has three upper arms and three lower arms corresponding to each of the U-phase, V-phase, and W-phase. In the second inverter circuit 5, the respective circuit structures related to the U-phase, V-phase, and W-phase are the same. Taking the three phases as representatives, the U-phase will be described. The second inverter circuit 5 has a second smoothing capacitor 35u, a second upper-arm side switching element 36au, a second lower-arm side switching element 37au, a second motor relay switching element 38au, and a second shunt resistor 39u. The second upper-arm side switching element 36au is provided on the upper arm, and the second lower-arm side switching element 37au is provided on the lower arm. The second upper-arm side switching element 36au is electrically connected to the positive electrode of the battery 9, and the second lower-arm side switching element 37au is electrically connected to the negative electrode of the battery 9. The second upper-arm side switching element 36au and the second lower-arm side switching element 37au are connected in series. The second motor relay switching element 38au is connected between the second upper-arm side switching element 36au and the second lower-arm side switching element 37au. The second motor relay switching element 38au has a relay function. That is, the second motor relay switching element 38au switches the on and off of the power supply to the winding Ub of the motor 2 from the portion between the second upper-arm side switching element 36au and the second lower-arm side switching element 37au. The second upper-arm side switching element 36au and the second lower-arm side switching element 37au are operated by the second FET drive circuit 15 based on the operation result of the CPU 10. As an example of the second upper-arm side switching element 36au, the second lower-arm side switching element 37au, and the second motor relay switching element 38au, a FET (Field Effect Transistor) can be adopted.

[0047] The second smoothing capacitor 35u is connected near the second upper-arm side switching element 36au and the second lower-arm side switching element 37au. The second smoothing capacitor 35u has the function of suppressing the power supply voltage fluctuation and noise during switching. The second shunt resistor 39u is directly connected between the second lower-arm side switching element 37au and the ground. The second shunt resistor 39u is used to detect the drive current flowing through the winding Ub of the motor 2. In addition, the second inverter circuit 5 may include a choke coil that suppresses the release of noise to the outside of the electronic control device 1 and suppresses the inflow of noise into the electronic control device 1.

[0048] As Figure 6As shown, three fourth semiconductor packages 36u, 36v, 36w corresponding to each of the U-phase, V-phase, and W-phase, three fifth semiconductor packages 37u, 37v, 37w, and three sixth semiconductor packages 38u, 38v, 38w are mounted on the first surface 20a of the wiring substrate 20. Three second shunt resistors 39u, 39v, 39w corresponding to each of the U-phase, V-phase, and W-phase are mounted on the first surface 20a of the wiring substrate 20.

[0049] The fourth semiconductor packages 36u, 36v, 36w have the same structure as the first semiconductor packages 31u, 31v, 31w. The fourth semiconductor package 36u (36v, 36w) includes a second upper arm side switching element 36au (36av, 36aw) and a fourth sealing member 36bu (36bv, 36bw) surrounding the second upper arm side switching element 36au (36av, 36aw). The fifth semiconductor packages 37u, 37v, 37w have the same structure as the second semiconductor packages 32u, 32v, 32w. The fifth semiconductor package 37u (37v, 37w) includes a second lower arm side switching element 37au (37av, 37aw) and a fifth sealing member 37bu (37bv, 37bw) surrounding the second lower arm side switching element 37au (37av, 37aw). The sixth semiconductor packages 38u, 38v, 38w have the same structure as the second semiconductor packages 33u, 33v, 33w. The sixth semiconductor package 38u (38v, 38w) includes a second motor relay switching element 38au (38av, 38aw) and a sixth sealing member 38bu (38bv, 38bw) surrounding the second motor relay switching element 38au (38av, 38aw).

[0050] In a top view, the area of the fourth semiconductor package 36u (36v, 36w) is smaller than the area of the sixth semiconductor package 38u (38v, 38w), and the area of the fifth semiconductor package 37u (37v, 37w) is smaller than the area of the sixth semiconductor package 38u (38v, 38w). In a top view, the area of the fourth semiconductor package 36u (36v, 36w) is the same as the area of the fifth semiconductor package 37u (37v, 37w). According to such a structure, compared with the case where the areas of the fourth semiconductor packages 36u, 36v, 36w and the fifth semiconductor packages 37u, 37v, 37w are the same as the areas of the sixth semiconductor packages 38u, 38v, 38w, the mounting area of the switching elements 36au, 36av, 36aw, 37au, 37av, 37aw, 38au, 38av, 38aw in the wiring substrate 20 can be reduced.

[0051] In addition, in this case, the heat dissipation of the fourth semiconductor packages 36u, 36v, 36w and the fifth semiconductor packages 37u, 37v, 37w is lower than that of the sixth semiconductor packages 38u, 38v, 38w. On the other hand, regarding the time during which current flows through each switching element in each cycle of the PWM drive of the electric motor 2, the time of the second upper arm side switching elements 36au (36av, 36aw) and the second lower arm side switching elements 37au (37av, 37aw) is shorter than that of the second motor relay switching elements 38au (38av, 38aw). Therefore, regarding the heat generation amount of each switching element, the heat generation amounts of the second upper arm side switching elements 36au (36av, 36aw) and the second lower arm side switching elements 37au (37av, 37aw) are smaller than those of the second motor relay switching elements 38au (38av, 38aw). Based on the above, the areas of the fourth semiconductor packages 36u, 36v, 36w and the fifth semiconductor packages 37u, 37v, 37w are smaller than those of the sixth semiconductor packages 38u, 38v, 38w, thereby maintaining the balance between the heat generation amount and the heat dissipation in each semiconductor package, and uniformly suppressing the temperature rise in the fourth semiconductor packages 36u, 36v, 36w, the fifth semiconductor packages 37u, 37v, 37w, and the sixth semiconductor packages 38u, 38v, 38w.

[0052] As described above, in the present embodiment, the electronic control device 1 further includes fourth semiconductor packages 36u, 36v, 36w, fifth semiconductor packages 37u, 37v, 37w, and sixth semiconductor packages 38u, 38v, 38w. The fourth semiconductor packages 36u, 36v, 36w include second upper arm side switching elements 36au, 36av, 36aw and fourth sealing members 36bu, 36bv, 36bw surrounding the second upper arm side switching elements 36au, 36av, 36aw. The fifth semiconductor packages 37u, 37v, 37w include second lower arm side switching elements 37au, 37av, 37aw and fifth sealing members 37bu, 37bv, 37bw surrounding the second lower arm side switching elements 37au, 37av, 37aw. The sixth semiconductor packages 38u, 38v, 38w include second motor relay switching elements 38au, 38av, 38aw and sixth sealing members 38bu, 38bv, 38bw surrounding the second motor relay switching elements 38au, 38av, 38aw. The fourth semiconductor packages 36u, 36v, 36w, the fifth semiconductor packages 37u, 37v, 37w, and the sixth semiconductor packages 38u, 38v, 38w are mounted on the first surface 20a of the wiring substrate 20. The second upper arm side switching elements 36au, 36av, 36aw, the second lower arm side switching elements 37au, 37av, 37aw, and the second motor relay switching elements 38au, 38av, 38aw form a second inverter circuit 5 that can supply current to the motor 2 through a path different from that of the inverter circuit 3. When viewed from above, the area of the fourth semiconductor packages 36u, 36v, 36w is smaller than the area of the sixth semiconductor packages 38u, 38v, 38w, and the area of the fifth semiconductor packages 37u, 37v, 37w is smaller than the area of the sixth semiconductor packages 38u, 38v, 38w. The inverter circuit 3 and the second inverter circuit 5 are configured to supply current to the motor 2 independently of each other, thereby ensuring redundancy. In addition, by reducing the mounting area of the switching elements 36au, 36av, 36aw, 37au, 37av, 37aw, 38au, 38av, 38aw in the wiring substrate 20, miniaturization of the wiring substrate 20 can be achieved.

[0053] Embodiment 3. Next, the electric power steering device according to Embodiment 3 will be described. The basic structure of the electric power steering device according to the present embodiment is the same as that of the electric power steering device of Embodiment 1, and thus the description will be centered on the differences.

[0054] As Figure 7 shown, in the present embodiment, the electronic control device 1 further includes a power relay switching element 61a and a reverse connection protection relay switching element 62a. The switching element 61a for the power relay switches the supply and cut-off of the current from the battery 9 to the inverter circuit 3. The switching element 62a for the reverse connection protection relay protects the inverter circuit 3 from the reverse flow of the current when the battery 9 is reversely connected. The switching element 61a for the power relay and the switching element 62a for the reverse connection protection relay are provided on the power supply line L1 connecting the battery 9 and the inverter circuit 3. The switching element 61a for the power relay and the switching element 62a for the reverse connection protection relay are connected in series. The parasitic diode of the switching element 62a for the reverse connection protection relay is connected in the opposite direction to the parasitic diode of the switching element 61a for the power relay. As an example of the switching element 61a for the power relay and the switching element 62a for the reverse connection protection relay, an FET (Field Effect Transistor) can be adopted.

[0055] As Figure 8 shown, the semiconductor package 61 for the power relay and the semiconductor package 62 for the reverse connection protection relay are mounted on the first surface 20a of the wiring substrate 20. The semiconductor package 61 for the power relay includes the switching element 61a for the power relay and the seventh sealing member 61b surrounding the switching element 61a for the power relay. The outer shape of the semiconductor package 61 for the power relay (the seventh sealing member 61b) is rectangular in a top view. The seventh sealing member 61b is made of resin, for example. The semiconductor package 62 for the reverse connection protection relay includes the switching element 62a for the reverse connection protection relay and the eighth sealing member 62b surrounding the switching element 62a for the reverse connection protection relay. The outer shape of the semiconductor package 62 for the reverse connection protection relay (the eighth sealing member 62b) is rectangular in a top view. The eighth sealing member 62b is made of resin, for example.

[0056] In a top view, the area of the semiconductor package 61 for the power relay is smaller than the area of the third semiconductor package 33u (33v, 33w), and the area of the semiconductor package 62 for the reverse connection protection relay is smaller than the area of the third semiconductor package 33u (33v, 33w). According to such a structure, compared with the case where the areas of the semiconductor package 61 for the power relay and the semiconductor package 62 for the reverse connection protection relay are the same as the area of the third semiconductor package 33u (33v, 33w), the mounting areas of the semiconductor package 61 for the power relay and the semiconductor package 62 for the reverse connection protection relay on the wiring substrate 20 can be reduced, and miniaturization of the wiring substrate 20 can be achieved.

[0057] Figure 9 is a top view of the wiring substrate 20 according to Modification 1 of Embodiment 3. As Figure 9As shown in the figure, in this modification example, when viewed from above, the area of the semiconductor package 61 for the power relay is equal to the area of the third semiconductor package 33u (33v, 33w), and the area of the semiconductor package 62 for the reverse connection protection relay is equal to the area of the third semiconductor package 33u (33v, 33w). In this case, the semiconductor package 61 for the power relay and the semiconductor package 62 for the reverse connection protection relay can be manufactured on the same production line as the third semiconductor package 33u (33v, 33w).

[0058] Figure 10 It is a circuit diagram of the electronic control device 1 and the electric power steering device 100 according to the modification example 2 of the embodiment 3. As Figure 10 shown, the switching element 61a for the power relay and the switching element 62a for the reverse connection protection relay can be provided on the ground wire L2 that connects the ground and the inverter circuit 3.

[0059] Embodiment 4. Next, the electric power steering device according to the embodiment 4 will be described. The basic structure of the electric power steering device according to this embodiment is the same as that of the electric power steering device of the embodiment 1, so the description will focus on the differences.

[0060] As Figure 11 shown, in this embodiment, the electronic control device 1 further includes a switching element 62a for the reverse connection protection relay. The switching element 62a for the reverse connection protection relay protects the inverter circuit 3 from the reverse flow of current when the battery 9 is reversely connected. The switching element 62a for the reverse connection protection relay is provided on the ground wire L2 that connects the ground and the inverter circuit 3.

[0061] As Figure 12 shown, the semiconductor package 62 for the reverse connection protection relay is mounted on the first surface 20a of the wiring board 20. The semiconductor package 62 for the reverse connection protection relay includes a switching element 62a for the reverse connection protection relay and an eighth sealing member 62b that surrounds the switching element 62a for the reverse connection protection relay. When viewed from above, the area of the semiconductor package 62 for the reverse connection protection relay is smaller than the area of the third semiconductor package 33u (33v, 33w). According to such a structure, compared with the case where the area of the semiconductor package 62 for the reverse connection protection relay is the same as the area of the third semiconductor package 33u (33v, 33w), the mounting area of the semiconductor package 62 for the reverse connection protection relay on the wiring board 20 can be reduced, and miniaturization of the wiring board 20 can be achieved.

[0062] Figure 13 It is a top view of the wiring board 20 according to the modification example of the embodiment 4. AsFigure 13 As shown, in this modification, when viewed from above, the area of the semiconductor package 62 for reverse connection protection relay is equal to the area of the third semiconductor package 33u (33v, 33w). In this case, the semiconductor package 62 for reverse connection protection relay can be manufactured on the same production line as the third semiconductor package 33u (33v, 33w).

[0063] In addition, the technical scope of the present disclosure is not limited to the above-described embodiments, and various modifications can be made without departing from the gist of the present disclosure.

[0064] For example, in Embodiment 3, the motor 2 may include two sets of three-phase windings (three-phase coils), and the electronic control device 1 may include an inverter circuit 3 that supplies power to the first three-phase windings Ua, Va, Wa and a second inverter circuit 5 that supplies power to the second three-phase windings Ub, Vb, Wb. In this case, the inverter circuit 3 and the second inverter circuit 5 may use the common power relay switch element 61a and the reverse connection protection relay switch element 62a, or may use two sets of power relay switch elements 61a and reverse connection protection relay switch elements 62a.

[0065] In Embodiment 4, the motor 2 may include two sets of three-phase windings (three-phase coils), and the electronic control device 1 may include an inverter circuit 3 that supplies power to the first three-phase windings Ua, Va, Wa and a second inverter circuit 5 that supplies power to the second three-phase windings Ub, Vb, Wb. In this case, the inverter circuit 3 and the second inverter circuit 5 may use the common reverse connection protection relay switch element 62a, or may use two sets of reverse connection protection relay switch elements 62a.

[0066] For example, the electronic control device 1 can be used for applications other than the electric power steering device 100. In addition, the above-described embodiments or modification examples can be appropriately combined. Reference Numeral Explanation

[0067] 1... Electronic control device, 2... Electric motor, 3... Inverter circuit, 4... Control circuit, 5... Second inverter circuit, 9... Battery, 20... Wiring board, 20a... First surface, 20b... Second surface, 24... Thermal connection member, 25... Heat conduction member, 31u, 31v, 31w... First semiconductor package, 31au, 31av, 31aw... Upper arm side switching element, 31bu, 31bv, 31bw... First sealing member, 32u, 32v, 32w... Second semiconductor package, 32au, 32av, 32aw... Lower arm side switching element, 32bu, 32bv, 32bw... Second sealing member, 33u, 33v, 33w... Third semiconductor package, 33au, 33av, 33aw... Motor relay switching element, 33bu, 33bv, 33bw... Third sealing member, 36u, 36v, 36w... Fourth semiconductor package, 36au, 36av, 36aw... Second upper arm side switching element, 36bu, 36bv, 36bw... Fourth sealing member, 37u, 37v, 37w... Fifth semiconductor package, 37au, 37av, 37aw... Second lower arm side switching element, 37bu, 37bv, 37bw... Fifth sealing member, 38u, 38v, 38w... Sixth semiconductor package, 38au, 38av, 38aw... Second motor relay switching element, 38bu, 38bv, 38bw... Sixth sealing member, 40... Electric motor main body, 45... Frame, 46... Housing, 61... Semiconductor package for power relay, 61a... Power relay switching element, 61b... Seventh sealing member, 62... Semiconductor package for reverse connection protection relay, 62a... Reverse connection protection relay switching element, 62b... Eighth sealing member, 100... Electric power steering device, L1... Power supply line, L2... Ground line.

Claims

1. An electronic control device for controlling an electric motor, characterized in that, Comprising: A wiring substrate having a first surface and a second surface on the opposite side of the first surface; A first semiconductor package having an upper-arm side switching element and a first sealing member surrounding the upper-arm side switching element; A second semiconductor package having a lower-arm side switching element and a second sealing member surrounding the lower-arm side switching element; A third semiconductor package having a motor relay switching element and a third sealing member surrounding the motor relay switching element; And A CPU that controls the upper-arm side switching element, the lower-arm side switching element, and the motor relay switching element, The first semiconductor package, the second semiconductor package, and the third semiconductor package are mounted on the first surface of the wiring substrate, The upper-arm side switching element, the lower-arm side switching element, and the motor relay switching element form an inverter circuit capable of supplying current to the motor, When viewed from above in the thickness direction of the wiring substrate, the area of the first semiconductor package is smaller than the area of the third semiconductor package, and the area of the second semiconductor package is smaller than the area of the third semiconductor package.

2. The electronic control device according to claim 1, wherein Further comprising: A fourth semiconductor package having a second upper-arm side switching element and a fourth sealing member surrounding the second upper-arm side switching element; A fifth semiconductor package having a second lower-arm side switching element and a fifth sealing member surrounding the second lower-arm side switching element; And A sixth semiconductor package having a second motor relay switching element and a sixth sealing member surrounding the second motor relay switching element, The fourth semiconductor package, the fifth semiconductor package, and the sixth semiconductor package are mounted on the first surface of the wiring substrate, The second upper-arm side switching element, the second lower-arm side switching element, and the second motor relay switching element form a second inverter circuit capable of supplying current to the motor through a path different from the inverter circuit, When viewed from above in the thickness direction of the wiring substrate, the area of the fourth semiconductor package is smaller than the area of the sixth semiconductor package, and the area of the fifth semiconductor package is smaller than the area of the sixth semiconductor package.

3. The electronic control device according to claim 1 or 2, characterized in that, Further comprising: A semiconductor package for a power relay having a power relay switching element for switching the supply and stop of current from a power source to the motor, and a seventh sealing member surrounding the power relay switching element; And A semiconductor package for an anti-reverse protection relay having an anti-reverse protection relay switching element for protecting the inverter circuit from the influence of reverse current flow, and an eighth sealing member surrounding the anti-reverse protection relay switching element, The semiconductor package for a power relay and the semiconductor package for an anti-reverse protection relay are mounted on the first surface of the wiring substrate, When viewed from above in the thickness direction of the wiring substrate, the area of the semiconductor package for the power relay is smaller than the area of the third semiconductor package, and the area of the semiconductor package for the reverse connection protection relay is smaller than the area of the third semiconductor package.

4. The electronic control device according to claim 1 or 2, characterized in that, Further included are: A semiconductor package for a power relay, which has a power relay switching element for switching the supply and stop of current from a power source to the motor, and a seventh sealing member surrounding the power relay switching element; And A semiconductor package for a reverse connection protection relay, which has a reverse connection protection relay switching element for protecting the inverter circuit from the influence of reverse current flow, and an eighth sealing member surrounding the reverse connection protection relay switching element, The semiconductor package for the power relay and the semiconductor package for the reverse connection protection relay are mounted on the first surface of the wiring substrate, When viewed from above in the thickness direction of the wiring substrate, the area of the semiconductor package for the power relay is equal to the area of the third semiconductor package, and the area of the semiconductor package for the reverse connection protection relay is equal to the area of the third semiconductor package.

5. The electronic control device according to claim 3 or 4, characterized in that, Further included are: The semiconductor package for the power relay and the semiconductor package for the reverse connection protection relay are provided on the power line connecting the power source and the inverter circuit.

6. The electronic control device according to claim 3 or 4, characterized in that, Further included are: The semiconductor package for the power relay and the semiconductor package for the reverse connection protection relay are provided on the ground wire connecting the ground and the inverter circuit.

7. The electronic control device according to claim 1 or 2, characterized in that Further included are: A semiconductor package for a reverse connection protection relay, which has a reverse connection protection relay switching element for protecting the inverter circuit from the influence of reverse current flow, and an eighth sealing member surrounding the reverse connection protection relay switching element, The semiconductor package for the reverse connection protection relay is mounted on the first surface of the wiring substrate and is provided on the ground wire connecting the ground and the inverter circuit, When viewed from above in the thickness direction of the wiring substrate, the area of the semiconductor package for the reverse connection protection relay is smaller than the area of the third semiconductor package.

8. The electronic control device according to claim 1 or 2, characterized in that, Further included are: A semiconductor package for a reverse connection protection relay, which has a reverse connection protection relay switching element for protecting the inverter circuit from the influence of reverse current flow, and an eighth sealing member surrounding the reverse connection protection relay switching element, The semiconductor package for the reverse connection protection relay is mounted on the first surface of the wiring substrate and is provided on the ground wire connecting the ground and the inverter circuit, When viewed from above in the thickness direction of the wiring substrate, the area of the semiconductor package for the reverse connection protection relay is equal to the area of the third semiconductor package.

9. An electric power steering device, characterized in that, Included are: The electronic control device according to any one of claims 1 to 8; And The motor controlled by the electronic control device.

10. The electric power steering device according to claim 9, characterized in that The motor includes a motor main body, a cylindrical frame housing the motor main body, and a housing fitted to the frame, The housing is configured to face the second surface of the wiring substrate, A thermal connection member for thermally connecting the housing and the wiring substrate is provided between the housing and the wiring substrate, A heat conduction member is provided on the wiring substrate, and the heat conduction member is arranged to penetrate from the first surface to the second surface and is thermally connected to the thermal connection member.

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