CONTROL UNIT AND ELECTRIC POWER STEERING DEVICE HAVING THE CONTROL UNIT

Abstract

Control unit (1, 2) with:- a rotating electrical machine (10, 210) with: (i) a stator (12) with a winding (13, 14) wound on the stator and a shaft (16) rotating within the stator, (ii) a rotor (15) rotatable with respect to the stator, (iii) a motor housing (11), and (iv) a frame element (20) attached to the motor housing (11);- a controller holding element (20, 220) arranged above the shaft;- a controller (40) comprising:- a substrate (41) attached to the controller support member, the substrate including:(i) an upwardly facing electronic component attachment surface (43), and(ii) a downwardly facing heat-generating element attachment surface (42),- a heat-generating element (70) attached to the downwardly facing heat-generating element attachment surface (42) to enable heat dissipation from the heat-generating element to the controller support member, and- electronic components (81, 86, 87, 89) attached to the upwardly facing electronic component attachment surface (43) of the substrate, the controller being arranged above the controller support member;- a power supply connector (96) configured to electrically connect the substrate to a power source (109);and- a substrate securing screw (49) forming an electrical path from the substrate (41) to the frame member (20) such that stray capacitance (C12) between the substrate (41) and the frame member (20) is reduced or eliminated, wherein the power supply connector (96) is arranged above the controller, and wherein the power supply connector (96) is further configured to electrically connect the substrate to a ground line (500);

Description

[0001] The present invention generally relates to a drive unit and an electric power steering apparatus having the drive unit.

[0002] A conventional structure of an electric motor used in a vehicle is susceptible to noise, i.e., a gap between a motor coil and a motor housing acts as a noise-generating capacitor. Such noise can be suppressed by the following structure. For example, in JP H04-355602 A (Patent Document 1), the generated noise is removed via a common-mode path provided as a connection between the motor parts and the vehicle body, i.e., a grounding of the motor housing and a heat sink to a vehicle body.

[0003] In Patent Document 1, the noise affecting the controller is reduced by connecting the engine casing and the heat sink to the vehicle body, and the noise escaping from the engine increases, as a trade-off. Furthermore, the noise escaping from the engine casing and the heat sink of the engine is common-mode noise, and there is no knowledge of the path such noise takes outside the engine. Consequently, the noise escaping from the engine casing and the heat sink of the engine is transmitted to an antenna of a radio, a communication device, and the like, eventually causing radio noise.

[0004] Further relevant prior art is known from DE 11 2010 002 702 T5, US 2014 / 0 153 198 A1, DE 10 2011 002 027 A, DE 10 2011 056 396 A1 and DE 10 2010 017 519 A1.

[0005] It is an object of the present invention to provide a motor or a drive unit having a noise suppression capability and an electric power steering apparatus using such a drive unit.

[0006] The problem is solved by the features of claims 1 or 10.

[0007] According to one aspect of the present invention, the drive unit comprises a rotating electrical machine having a stator with a winding wound on the stator, a shaft rotating within the stator, and a rotor rotatable relative to the stator. The drive unit also comprises a controller support element arranged at one end of the rotating electrical machine and a controller.

[0008] The controller includes: a substrate fixed to the controller holding member, a heat generating element fixed to a heat generating element fixing surface that is a controller holding member-side surface of the substrate that allows heat dissipation from the heat generating element to the controller holding member, and electronic components fixed to an electronic component fixing surface of the substrate opposite to the heat generating element fixing surface.

[0009] The drive unit further includes a power supply connector connecting the substrate and a power source, and a ground line connected to a ground terminal of the power source, providing a conductive connection to the controller support member via the substrate and the power supply connector. With such a configuration, even if a stray capacitance between the controller support member and the substrate serves as a noise propagation path, that is, even if generated noise propagates through such a path, such noise returns to the power supply ground line via the power supply connector. Consequently, the noise caused by the stray capacitance is considered normal-mode noise.More specifically, the configuration of the present invention enables the noise that would otherwise cause the common-mode noise to be collected and returned to the power source as a normal-mode noise.

[0010] Consequently, by reducing common-mode noise in the manner described above, the noise suppression configuration for reducing common-mode noise is simplified. Furthermore, in a situation where a drive unit and an on-board radio are present together in a vehicle, radio noise is reduced by reducing engine noise, that is, reducing the noise escaping from the drive unit via the controller support member.

[0011] The objects, features, and advantages of the present invention will become more apparent from the following detailed description with reference to the accompanying drawings. In the drawings: Fig. 1 is a system diagram of an electric power steering apparatus according to a first embodiment of the present invention; Fig. 2 is a schematic diagram of a circuit arrangement of a drive unit in the first embodiment of the present invention; Fig. 3 is a sectional view of the drive unit in the first embodiment of the present invention; Fig. 4 is a side view of the drive unit in the first embodiment of the present invention; Fig. 5 a plan view of the control unit along the arrow V in the Fig. 4; Fig. 6 a bottom view of the control unit along the arrow VI in the Fig. 4; Fig. 7 is an exploded perspective view of the drive unit in the first embodiment of the present invention; Fig. 8 is another exploded perspective view of the drive unit in the first embodiment of the present invention; Fig. 9 is a side view of an engine control unit (ECU) in the first embodiment of the present invention; Fig. 10 a bottom view of the ECU along the arrow X in the Fig. 9; Fig. 11 a plan view of the ECU along the arrow XI in the Fig. 9; Fig. 12 is a diagram showing a noise propagation path in the drive unit of the first embodiment of the present invention; Fig. 13 is a sectional view of the drive unit according to a second embodiment of the present invention; Fig. 14 is a side view of the drive unit in the second embodiment of the present invention; Fig. 15 a plan view of the control unit along the arrow XV in the Fig. 14; and Fig. 16 a bottom view of the control unit along the arrow XVI in the Fig. 14.

[0012] The control unit and electric power steering apparatus according to the invention are described below with reference to the drawings. (First embodiment)

[0013] The drive unit of the first embodiment of the present disclosure and the electric power steering apparatus are shown in the Fig. 1 to 12. In all embodiments, identical parts are designated by the same reference numerals to avoid redundancy.

[0014] A control unit 1 is, as in Fig. 1, is applied to an electric power steering device 8 for assisting a driver's steering operation. The drive unit 1 is a single-body combination of a motor 10 serving as a rotating electric machine and an ECU 40 serving as a controller for controlling the motor 10.

[0015] Fig. 1 shows a system diagram of a steering system 100 including the electric power steering device 8. The steering system 100 includes a steering wheel 101, a steering column 102, a gear train 104, a rack 105, wheels 106, the electric power steering device 8, and the like, each serving as a component of the system.

[0016] The steering wheel 101 is connected to the steering column 102. The steering column 102 has a torque sensor 103 mounted thereon, which is used to detect a steering torque applied thereto when the driver operates the steering wheel 101. At a tip of the steering column 102, the gear train 104 is arranged, which meshes with the rack 105. A pair of wheels 106 are arranged at both ends of the rack 105 via a tie rod and the like.

[0017] Consequently, the steering column 102 connected to the steering wheel 101 rotates when the driver operates the steering wheel 101. The rotational movement of the steering column 102 is converted by the gear train 104 into a translational movement of the rack 105, and the pair of wheels 106 are steered at an angle corresponding to an amount of displacement of the rack 105.

[0018] The electric power steering device 8 includes a reduction gear 9 serving as a power transmission portion and the drive unit 1. The electric power steering device 8 outputs the assist torque from the motor 10 based on the signals from the torque sensor 103 and the vehicle speed obtained from a CAN (Control Area Network) not shown, and transmits the torque to the steering column 102 via the reduction gear 9 to assist the steering operation of the steering wheel 101. That is, the electric power steering device 8 of the present embodiment is of a "column assist" type that assists rotation of the steering column 102 with the torque generated by the motor 10. However, the device 8 can also be used as a "rack assist" type that assists the driving of the rack 105.More specifically, the steering column 102 serving as a “drive object” in the present embodiment may be replaced by other objects such as the rack 105.

[0019] The electrical configuration of the electric power steering device 8 is described below with reference to Fig. 2. In the Fig. 2, some control lines and the like are omitted for the sake of readability of the figure.

[0020] The motor 10 is a brushless three-phase motor and has a first winding group 13 and a second winding group 14, each wound on the stator 12, which will be described below.

[0021] The first winding group 13 includes a U-phase coil 131, a V-phase coil 132, and a W-phase coil 133. The second winding group 14 includes a U-phase coil 141, a V-phase coil 142, and a W-phase coil 143.

[0022] According to the present embodiment, the first winding group 13 and the second winding group 14 each correspond to a “winding”.

[0023] The ECU 40 includes a first inverter section 50, a second inverter section 60, power relays 71 and 72, reverse-connected protective relays 73 and 74, a control unit 80, a rotation angle sensor 85, capacitors 86 and 87, and a reactor 89 serving as a coil element, each of which is mounted on a substrate 41, which will be described later. In the present embodiment, the electronic components constituting the ECU 40 are mounted on a substrate 41. With such a configuration, the number of components in the ECU 40 is reduced compared to a case where multiple circuit boards 41 are used, thereby reducing the volume of the ECU 40.

[0024] The first inverter part 50 has six switching elements (SW elements) 51-56 combined in the form of a bridge circuit for switching the power supply to the first winding group 13. The second inverter part 60 has six SW elements 61-66 in the form of a bridge circuit for switching the power supply to the second winding group 14.

[0025] Although the SW elements 51-56, 61-66 of the present embodiment are metal oxide semiconductor field effect transistors (MOSFETs), other elements such as insulated gate bipolar transistors (IGBTs) and the like may also be used.

[0026] As for the SW elements 51, 52 and 53 arranged on the high potential side of the first inverter part 50, the drain is connected to a positive electrode of a battery 109 serving as a power source, and the source is connected to the drain of the SW elements 54, 55 and 56 arranged on the low potential side.

[0027] The source of the SW elements 54, 55, and 56 is connected to a negative electrode of the battery 109 via current detection elements 57, 58, and 59. The nodes among the SW elements 51, 52, and 53 on the high potential side and the SW elements 54, 55, and 56 on the low potential side are connected to the U-phase coil 131, the V-phase coil 132, and the W-phase coil 133, respectively.

[0028] As for the SW elements 61, 62 and 63 arranged on the high potential side of the second inverter part 60, the drain is connected to the positive electrode of the battery 109 and the source is connected to the drain of the SW elements 64, 65 and 66 arranged on the low potential side.

[0029] The source of the SW elements 64, 65, and 66 is connected to the negative electrode of the battery 109 via current detection elements 67, 68, and 69. The nodes among the SW elements 61, 62, and 63 on the high potential side and the SW elements 64, 65, and 66 on the low potential side are connected to the U-phase coil 141, the V-phase coil 142, and the W-phase coil 143, respectively.

[0030] The current detecting elements 57, 58 and 59 are arranged on the low potential side of the SW elements 54, 55, 56 respectively corresponding to the three phases of the first winding group 13 to detect the electric current in each of the three phases of the first winding group 13.

[0031] The current detecting elements 67, 68 and 69 are arranged on the low potential side of the SW elements 64, 65 and 66 respectively corresponding to the three phases of the second winding group 14 to detect the electric current in each of the three phases of the second winding group 14.

[0032] The current detection elements 57-59, 67-69 of the present embodiment are realized as shunt resistors.

[0033] The power relay 71 is arranged at a position between the battery 109 and the first inverter part 50 and conducts and interrupts the electric current between the battery 109 and the first inverter part 50.

[0034] The power relay 72 is arranged at a position between the battery 109 and the second inverter part 60 and conducts and interrupts the electric current between the battery 109 and the second inverter part 60.

[0035] The reverse-connected protection relay 73 is arranged at a position between the power relay 71 and the first inverter part 50. The reverse-connected protection relay 74 is arranged at a position between the power relay 72 and the second inverter part 60.

[0036] The reverse-connected protective relays 73 and 74 prevent the electric current from flowing in the reverse direction, such as in a case where the battery 109 is connected upside down, by having a parasitic diode connected in the reverse direction with respect to the power relays 71 and 72, to protect the ECU 40.

[0037] In the present embodiment, the power relays 71 and 72 and the reverse-connected protective relays 73 and 74 are all MOSFETs. However, other semiconductor elements, such as IGBTs and the like, may also be used as these relays. In the present embodiment, the power relays 71 and 72 and the reverse-connected protective relays 73 and 74 each correspond to a "relay."

[0038] The control unit 80 includes a microcomputer 81 serving as an electronic component and a calculation circuit, and an application-specific integrated circuit (ASIC) 82 serving as an IC (integrated circuit) circuit, along with other parts that are IC components.

[0039] The microcomputer 81 calculates a command value regarding the power supply to the first winding group 13 and the second winding group 14 based on the signal from the torque sensor 103, the rotation angle sensor 85 and the like.

[0040] The ASIC 82 includes a preamplifier, a signal amplifier, a regulator, and the like. The preamplifier generates a drive signal based on the command value and outputs the generated drive signal to the first inverter part 50 and the second inverter part 60. More specifically, the preamplifier outputs the generated drive signal to the gate of the SW elements 51-56, 61-66. By switching the SW elements 51-56, 61-66 according to the drive signal, an alternating current in accordance with the command value is supplied from the first inverter part 50 and the second inverter part 60 to the first winding group 13 and the second winding group 14, respectively. In this way, the motor 10 is driven.

[0041] The signal amplifier amplifies the detection signal (ie, a voltage between both terminals in the present embodiment) of the current detection elements 57-59, 67-69 and the detection value of the rotation angle sensor 85 and outputs them to the microcomputer 81. Further, the regulator is a stabilizing circuit that stabilizes the voltage applied to the microcomputer 81 and the like.

[0042] The rotation angle sensor 85 has a magnetism detecting element and detects a rotation angle of a rotor 15 by detecting a rotating magnetic field from a magnet 18 provided at another end 162 of a shaft 16, which will be described later.

[0043] The capacitor 86 is connected in parallel to the first inverter part 50. The capacitor 87 is connected in parallel to the second inverter part 60. In the present embodiment, the capacitors 86 and 87 are aluminum electrolytic capacitors and are arranged on the inverter side (i.e., on a side close to the inverter parts 50, 60) of the relays 71-74. The choke coil 89 is connected at a position between the battery 109 and the positive electrodes of the capacitors 86 and 87. In the present embodiment, the choke coil 89 is arranged on the battery side (i.e., on a side close to the battery 109) of the relays 71-74.Capacitors 86 and 87 and choke coil 89 serve as a filter circuit that reduces the noise transmitted from drive unit 1 to other devices that share the power supply from battery 109 with drive unit 1, and also reduces the noise transmitted back to drive unit 1 from other devices that share the battery 109. Capacitors 86 and 87 store electrical charge and support the electrical power supply to the first inverter section 50 and the second inverter section 60.

[0044] The ground terminal of the battery 109 is connected to the ground line. Hereinafter, the ground line connected to the ground terminal of the battery 109 is referred to as a "power supply ground line 500."

[0045] In the present embodiment, the first inverter part 50, the power relay 71, the reverse-connected protective relay 73, and the capacitor 86 are grouped as a first system 201 corresponding to the first winding group 13. Furthermore, the second inverter part 60, the power relay 72, the reverse-connected protective relay 74, and the capacitor 87 are grouped as a second system 202 corresponding to the second winding group 14. That is, the motor 10 is controlled in multiple systems, ie, in two systems in the present embodiment.

[0046] The following is a structure of the control unit 1 with reference to the Fig. 3 to 11. Hereinafter, an axial direction of the motor 10 may be simply referred to as an "axial direction" and a radial direction of the motor 10 may be simply referred to as a "radial direction." Fig. 3 shows a sectional view along the line III-III in the Fig. 5.

[0047] The control unit 1 has, as shown in the Fig. 3 to 8, the motor 10, a frame member 20 serving as a controller holding member, the ECU 40 and a power supply connector 96 together with other parts.

[0048] The motor 10 has, as shown in the Fig. 3, a motor housing 11 serving as a housing of the motor 10, a stator 12, the first winding group 13, the second winding group 14, the rotor 15, the shaft 16 and other parts.

[0049] The motor housing 11 includes, for example, a bottom portion 111 and a cylinder portion 114, is formed in the shape of a cylinder closed at one end, that is, having a bottom at one end, and is made of metal such as aluminum. The motor housing 11 of the present embodiment is made of aluminum, and the surface of the housing 11 is anodized. The bottom portion 111 of the motor housing 11 is located away from the ECU 40, that is, on an opposite side, and an opening of the motor housing 11 is located near the ECU 40, that is, on the ECU side. In the present embodiment, the cylinder portion 114 corresponds to a "cylinder portion of the rotating electrical machine," and a projection area of the cylinder portion 114 in the axial direction corresponds to a "motor portion."

[0050] A shaft hole 112, into which one end 161 of the shaft 16 is inserted, is arranged substantially in the center of the base part 111. Furthermore, a bearing 166 is fixed to the base part 111.

[0051] At or around the opening of the cylinder part 114, a mounting lug 116 is formed for rigidly mounting the frame element 20, ie, projecting outward from an outer wall of the cylinder part 114. The mounting lug 116 has a screw threaded hole 117 drilled therein. The mounting lug 116 of the present embodiment is arranged at three positions at equal intervals around the cylinder part 114.

[0052] The stator 12 includes a laminated portion, i.e., a laminated structure of a magnetizable thin metal, such as iron, and an insulator disposed radially outside the laminated portion, and is disposed within the motor housing 11. The number of thin metal sheets in the laminated portion of the stator 12 can be changed in accordance with the required output of the motor 10. Consequently, the output of the motor 10 can be changed by changing the axial length of the stator 12 without changing the radial length of the motor 10.

[0053] The first winding group 13 and the second winding group 14 are wound on the insulator of the stator 12. For each of the three phases, a first motor line 135 is led out of the first winding group 13, and for each of the three phases, a second motor line 145 is led out of the second winding group 14. The motor lines 135 and 145 are led out of the motor housing 11 toward the ECU 40, i.e., they extend from the motor housing 11 toward the ECU 40 (see Fig. 7).

[0054] The first motor line 135 includes a first U-phase motor line 136 and a first V-phase motor line 137 and a first W-phase motor line 138, and the three lines 136, 137, 138 are positioned in a numerically ascending order away from the power relays 71 and 72.

[0055] The second motor line 145 has a second U-phase motor line 146 and a second V-phase motor line 147 and a second W-phase motor line 148, and the three lines 146, 147, 148 are positioned in a numerically descending order away from the power relays 71 and 72.

[0056] The first U-phase motor line 136 and the second U-phase motor line 146, the first V-phase motor line 137 and the second V-phase motor line 147, and the first W-phase motor line 138 and the second W-phase motor line 148 are each arranged at point-symmetrical positions around a central axis O of the motor 10, which will be described later. Furthermore, the first U-phase motor line 136 and the first W-phase motor line 138 are positioned symmetrically with respect to the first V-phase motor line 137. Similarly, the second U-phase motor line 146 and the second W-phase motor line 148 are positioned symmetrically with respect to the second V-phase motor line 147.

[0057] Consequently, the leakage magnetic flux from the first motor line 135 and the leakage magnetic flux from the second motor line 145 cancel each other out. Furthermore, in such a configuration, the influence of the leakage magnetic flux on the rotation angle sensor 85, which is mounted at a position on the central axis O of the motor 10, is reduced, thereby reducing the detection error of the sensor 85.

[0058] “Symmetrical” herein describes a substantially symmetrical arrangement of these leads to cancel out magnetic flux leakage, which allows for dimensional error in the actual product.

[0059] The rotor 15 has a rotor core 151 and a permanent magnet 152. The rotor core 151 is formed, for example, in an approximately cylindrical shape and constructed from a magnetic material such as iron, and is arranged coaxially within the stator 12, ie, radially within the stator 12.

[0060] The permanent magnet 152 is arranged on a radius outside the rotor core 151, and N-poles and S-poles of the rotor core 151 alternate with each other.

[0061] The shaft 16 is constructed in a rod shape, for example, from metal, and is fitted at the central position, i.e., at a rotational axis of the rotor core 151. The shaft 16 is rotatably supported by the bearing 166 fixed to the bottom part 111 of the motor housing 11 and by a bearing 167 fixed to the frame member 20. This allows the shaft 16 to rotate with the rotor 15. Furthermore, an outer wall of the rotor 15 and an inner wall of the stator 12 are arranged with an air gap therebetween.

[0062] One end 161 of the shaft 16 is inserted into the shaft hole 112 bored in the bottom part 111 of the motor housing 11 and protrudes outside the motor housing 11. One end 161 of the shaft 16 serves as an output end 165 connected to the reduction gear 9 for outputting the torque from the motor 10 via the reduction gear 9 toward the steering column 102 (see Fig. 1), even if a connection between the output end and the reduction gear 9 is not explicitly shown.

[0063] The other end 162 of the shaft 16 has a magnet holding element part 17 which holds the magnet 18.

[0064] The frame element 20 made of a highly thermally conductive metal, such as aluminum or the like, is, for example, as shown in the Fig. 3 and Fig. 7, formed in a lid shape for closing the opening of the engine housing 11, that is, inserted into an interior of the cylinder part 114. One side of the frame member 20 near the engine 10 is referred to herein as an engine-side surface 21, and the other side of the frame member 20 remote from the engine 10 and near the ECU 40 is referred to herein as an ECU-side surface 31.

[0065] A shaft hole 23 is drilled substantially in the center of the frame member 20. The other end 162 of the shaft 16 is inserted into the shaft hole 23. Consequently, the magnet 18, which is located at the other end 162 of the shaft 16, is exposed to the ECU 40, i.e., faces the ECU 40. The bearing 167 is fixed to the frame member 20.

[0066] Furthermore, the frame member 20 has a motor wire insertion hole 24 into which the motor wire 135 is inserted, and a motor wire insertion hole 25 into which the motor wire 145 is inserted. Thus, the motor wires 135 and 145 are led out of these holes to extend toward the ECU 40.

[0067] The frame member 20 has a fastening lug 26 that protrudes radially outward at positions (i.e., three positions in the present embodiment) corresponding to the fastening lug 116 of the motor housing 11. The fastening lug 26 has a through-hole 27 drilled therein. A frame locking screw 38, which serves as a "fastening element," is inserted into the through-hole 27 and firmly screwed into the screw hole 117. In this way, the frame member 20 is fastened to the motor housing 11.

[0068] Here, one side of the mounting boss 116 near the ECU 40 is a first contact surface 118, and the other side of the mounting boss 26 near the motor 10 is a second contact surface 268. In the present embodiment, although aluminum anodizing is performed on the surface of the motor housing 11, the first contact surface 118 is flattened, i.e., smoothed, to remove such conductivity treatment. In the present embodiment, the first contact surface 118 and the second contact surface 268 each serve as a "conduction part between the housing member and the controller holding member."

[0069] In the present embodiment, the first contact surface 118 and the second contact surface 268 are firmly connected to each other via the frame locking screw 38. This electrically connects the motor housing 11 and the frame member 20. Furthermore, using a conductive frame locking screw 38, the electrical connection between the motor housing 11 and the frame member 20 is also established by the frame locking screw 38.

[0070] On an outer periphery of the frame member 20 and around the motor-side surface 21, which is closer than the mounting boss 26 to the bottom part 111, an O-ring groove 29 is provided, into which an O-ring 39 is fitted. The O-ring 39, defined by the O-ring groove 29 and the cylindrical part 114, provides a waterproof structure. This prevents water and the like from entering the motor 10 via a position between the motor housing 11 and the frame member 20.

[0071] The ECU-side surface 31 of the frame element 20 has a substrate mounting tab 32, relay spaces 33 and 34, an ASIC space 35, a terminal receiving groove 36 and an adhesive groove 37.

[0072] The ECU 40 is, as in the Fig. 3, 7-11, arranged remotely from the engine 10 with respect to the frame member 20, ie, with the frame member 20 therebetween. The ECU 40 is positioned substantially within the engine area, ie, arranged substantially coaxially with the engine 10.

[0073] The ECU 40 has the substrate 41 to which many electronic components are attached.

[0074] The substrate 41 is formed in a shape that fits within the motor compartment. More practically, in the present embodiment, the substrate 41 is contained within the groove area, i.e., radially inside the bonding groove 37 provided on the ECU-side surface 31 of the frame member 20. Specifically, the ECU components on the substrate 41, such as the SW elements 51-56, 61-66, the current detection elements 57-59, 67-69, the capacitors 86 and 87, and the reactor 89, are positioned within the motor compartment.

[0075] Herein, one side of the substrate 41 near the motor 10 is referred to as a heat generating element mounting surface 42, and the other side, a side facing away from the motor 10, is referred to as an electronic component mounting surface 43.

[0076] The SW elements 51-56, 61-66 as well as the current measuring elements 57-59, 67-69, the power relays 71 and 72, the counter-connected protection relays 73 and 74, the ASIC 82 and the rotation angle sensor 85 are, as shown in the Fig. 8 and Fig. 10, together with other parts, is surface-mounted on the heat generating element mounting surface 42. The rotation angle sensor 85 is shown in the figure in the Fig. 10 omitted. In the Fig. 11, a dashed line shows an area in which a molded package of the ASIC 82 is arranged.

[0077] The rotation angle sensor 85 is mounted substantially at a central position on the heat generating element mounting surface 42 facing the magnet 18 exposed from the frame member 20. Herein, when the axis line of the shaft 16 and its extension are regarded as the central axis O of the motor 10, the rotation angle sensor 85 is mounted on the central axis O of the heat generating element mounting surface 42 (see Fig. 3).

[0078] A first region R1, in which the SW elements 51-56 of the first inverter part 50 are mounted, and a second region R2, in which the SW elements 61-66 and the current detection elements 67-69 of the second inverter part 60 are mounted, are arranged symmetrically on opposite sides of the central axis O of the motor 10. In the present embodiment, the SW elements 51-56 and the SW elements 61-66 are arranged axisymmetrically on both sides of a straight line passing through the central axis O of the motor 10.

[0079] The three phases U, V, W are arranged sequentially from the relay 71 side in the first inverter part 50, and the three phases W, V, U are arranged sequentially from the relay 72 side in the second inverter part 60, resulting in a point-symmetric relationship between the two inverters 50, 60 for the three phases. In the present embodiment, the phase arrangement sequence of the second system 202 has a reverse order to the phase arrangement sequence of the first system 201.

[0080] Consequently, while the impedance is reduced, the wiring length in each of the three phases on the substrate 41 is substantially equalized, and the change in impedance in each of the three phases is reduced or equalized. The above term "symmetry" describes a substantially symmetrical arrangement of the three phases, which allows for a dimensional error in the actual product.

[0081] Further, the SW elements 54-56 connected to the low potential side are arranged on the outside of the SW elements 51-53 connected to the high potential side, and the current detection elements 57-59 are arranged further outside thereof.

[0082] Similarly, the SW elements 64-66 connected to the low potential side are arranged on the outside of the SW elements 61-63 connected to the high potential side, and the current detecting elements 67-69 are arranged further outside thereof.

[0083] The SW elements 51-56, 61-66, the current sensing elements 57-59, 67-69, the power relays 71, 72, the reverse-connected protective relays 73, 74, and the ASIC 82, which are arranged on the heat-generating element mounting surface 42, each contact the ECU-side surface 31 of the frame member 20 in a heat-transfer manner via a thermal grease (not shown). In this way, heat generated by the SW elements 51-56, 61-66, the current sensing elements 57-59, 67-69, the power relays 71, 72, the reverse-connected protective relays 73, 74, and the ASIC 82 is dissipated to the frame member 20 via the thermal grease. Fig. 3 or the other figures, the ASIC 82 and the frame member 20 may appear to be arranged in a non-contact state because the thermal paste is omitted.

[0084] That is, the SW elements 51-56, 61-66, the current detection elements 57-59, 67-69, the power relays 71, 72, the reverse-connected protection relays 73, 74 and the ASIC 82 describe a heat generating element 70 in the present embodiment.

[0085] The power relays 71, 72, which are large elements compared to the SW elements 51-56, 61-66 and the counter-connected protection relays 73, 74, are housed in the relay compartments 33, 34 provided on the ECU-side surface 31 of the frame element 20.

[0086] The ASIC 82, which is a large element compared to the SW elements 51-56, 61-66 and the counter-connected protective relays 73, 74, is housed in the ASIC space 35 provided on the ECU-side surface 31 of the frame element 20.

[0087] In the present embodiment, the frame member 20, which is arranged at one end of the engine 10 in the axial direction, defines an outline of the engine 10, the frame member 20 provides support for the ECU 40, and the frame member 20 forms a heat dissipation path for dissipating heat from the heat generating element 70. In this way, compared with a case where a heat sink is separately provided, the number of components and the volume of the drive unit are reduced.

[0088] The microcomputer 81, the capacitors 86, 87 and the choke coil 89 are, as shown in the Fig. 7 and Fig. 11, together with other parts, are mounted on the electronic component mounting surface 43. In the present embodiment, the microcomputer 81, the capacitors 86, 87, and the choke coil 89 are synonymous with "electronic components" in the claims.

[0089] The microcomputer 81 is, as in Fig. 11, at a position on a back side of the substrate 41, ie partially overlapping with the ASIC 82.

[0090] The capacitor 86 is mounted on a back side of the substrate 41, i.e., partially overlapping the first region R1 in which the SW elements 51-56 of the first inverter part 50 are mounted. The capacitor 87 is mounted on a back side of the substrate 41, i.e., partially overlapping the second region R2 in which the SW elements 61-66 of the second inverter part 60 are mounted. The noise reduction effect is increased by arranging the capacitors 86, 87 on the back sides of the inverter parts 50, 60.

[0091] In the present embodiment, by mounting relatively large electronic components, such as capacitors 86, 87 and choke coil 89, on electronic component mounting surface 43, substrate 41 is positioned near frame member 20. In this way, heat generated by heat generating element 70 on heat generating element mounting surface 42 is dissipated from the "back" of these components to frame member 20.

[0092] A position radially outside the first region R1 has a motor lead insertion hole 44 drilled therethrough. The motor lead 135 is inserted into the motor lead insertion hole 44. A position radially outside the second region R2 has a motor lead insertion hole 45 drilled therethrough. The motor lead 145 is inserted into the motor lead insertion hole 45.

[0093] On the electronic component mounting surface 43, a motor lead connector 46 made of a conductive metal or the like is provided at a position where the motor lead insertion holes 44 and 45 are drilled. The motor lead connector 46 has a press-fit portion, and the press-fit portion, which receives the motor leads 135 and 145, establishes an electrical connection between the substrate 41 and the motor leads 135, 145.

[0094] A hole 48 is drilled at a position corresponding to the substrate fixing tab 32 of the substrate 41. A substrate securing screw 49 (see Fig. 7 and Fig. 8), which is formed of a conductive material that conducts electrical current, is inserted into the hole 48 and firmly screwed to the substrate securing tab 32 of the frame member 20. The substrate 41 is firmly attached to the frame member 20 by the axial force of the substrate securing screw 49, while simultaneously establishing an electrical connection between the two. Similar to the frame securing screw 38, if the securing screw 49 is formed of the conductive material, the electrical connection is also established via the substrate securing screw 49.

[0095] Hole 48 is drilled into a region of substrate 41 where a ground pattern is formed. The ground pattern on substrate 41 is electrically connected to power supply ground line 500 via power supply connector 96.

[0096] As described above, the motor housing 11 and the frame member 20 are electrically connected via the frame securing screw 38. Consequently, the motor housing 11 and the frame member 20 are electrically connected to the power supply ground line 500 via the substrate securing screw 49, the substrate 41, and the power supply connector 96.

[0097] A cover element 90 has, as shown in the Fig. 3-5, 7 and 8, a cover body 91, the power supply connector 96 and a signal connector 97 and covers the electronic component mounting surface 43 side of the substrate 41.

[0098] An insertion portion 921 is provided at one end of a peripheral wall 92 of the cover body 91. The insertion portion 921 is inserted into the adhesive groove 37 of the frame member 20 and secured by the adhesive. This prevents water or the like from entering the motor 10 via a connecting portion between the frame member 20 and the cover member 90.

[0099] A capacitor chamber 93 is formed substantially in the center of the cover body 91. The capacitor chamber 93 protrudes from the cover body 91, i.e., away from the motor 10, to accommodate the capacitors 86 and 87. An air hole 94 is drilled into the capacitor chamber 93. The air hole 94 has a filter element 95 attached thereto. The filter element 95 is constructed of a material that is permeable to air but not to water. The filter element 95 in the air hole 94 maintains a constant internal pressure of the control unit 1 even during temperature changes.

[0100] The power supply connector 96 and the signal connector 97 (hereinafter referred to as "connectors 96 and 97") each protrude from the cover body 91, ie, from the motor 10. In the present embodiment, the connectors 96 and 97 are formed integrally with the cover body 91.

[0101] The power connector 96 has an opening 961 located at one end extending away from the motor 10 for connection to a wiring harness (not shown) extending from the battery 109. Furthermore, the power connector 96 has a power connector terminal 962 connected to the substrate 41. The power connector terminal 962 is inserted into a terminal insertion hole 965 drilled in the substrate 41 and is connected to the substrate 41 by solder or the like. In this way, the ECU 40 is connected to the battery 109.

[0102] The signal connector 97 has an opening 971 located at one end extending from the engine 10 for connection to a wiring harness (not shown). In the present embodiment, two signal connectors 97 are provided, one of which connects to a wiring harness extending from the torque sensor 103, and the other of which connects to a wiring harness extending from the CAN. Further, the signal connector 97 has a signal connector terminal 972 connected to the substrate 41. The signal connector terminal 972 is inserted into a terminal insertion hole 975 provided on the substrate 41 and connected to the substrate 41 by solder or the like. In this way, information from the torque sensor 103 and information from the CAN are supplied to the ECU 40.

[0103] The tip of each of the power supply connector terminal 962 and the signal connector terminal 972 (hereinafter, the “terminals 962 and 972”) is inserted into the terminal receiving groove 36 formed on the ECU-side surface 31 of the frame member 20 so that the terminals 962, 972 and the frame member 20 are not short-circuited to each other.

[0104] The connectors 96, 97 extend away from the motor 10 on the cover body 91, with their heights projecting beyond the capacitor spaces 93 (i.e., the capacitor space 93 remains substantially "hidden" below the connector height). Furthermore, in the axial view of the motor 10, the connectors 96 and 97 are positioned within the motor area, at positions radially outside the capacitors 86, 87, i.e., farther than the capacitors 86, 87 from the central axis O of the motor 10. More specifically, a connector arrangement area and a capacitor arrangement area do not overlap in the axial view of the motor 10.

[0105] Consequently, compared with a conventional configuration in which the connector arrangement portion and the capacitor arrangement portion overlap each other, the size along the axis (ie, the height) of the drive unit 1 is smaller in the present invention, while at the same time preventing the increase in the diameter / radius of the drive unit 1.

[0106] Below is a noise propagation path in the drive unit 1 with reference to Fig. 12 described.

[0107] Fig. Fig. 12 shows a combined diagram, ie a combination of a schematic diagram and a sectional view, with respect to the control unit 1, from which the second inverter part 60, the current detection elements 57-59, the power relays 71 and 72 and the reverse-connected protection relays 73 and 74 are omitted. Furthermore, in the Fig. 12, the electronic components are attached to the substrate 41 within a rectangle that describes the substrate 41. In this assumption, the dashed line shows a noise propagation path formed by the stray capacitances C11 and C12, the motor housing 11, the frame member 20, the frame securing screw 38, and the substrate securing screw 49.

[0108] The rotor 15 and the shaft 16 are, for the sake of understanding, as in Fig. 12, are combined as a "motor section," and the motor housing 11 and the stator 12 are combined as a "casing." The air gap between the ground section and the casing creates the stray capacitance C12.

[0109] When the stray capacitances C11 and C12 are caused in the air gap, the noise generated by the driving of the motor section, the switching of the SW elements 51-56, 61-66, and the like propagates to the motor case 11 via the stray capacitances C11 and C12. Once the noise propagates to the motor case 11, it turns into common-mode noise, and may further propagate to the battery 109 via the vehicle body ground and the like. Furthermore, if the noise propagates to the outside of the drive unit 1 (such as the vehicle body and the like) via the motor case 11, it may further propagate to the antenna of the on-vehicle radio (not shown), causing radio noise.

[0110] Therefore, in the present embodiment, the motor housing 11 and the frame member 20 are each electrically connected to the power supply ground line 500 to electrically connect the stray capacitances C11 and C12 to the power supply ground line 500.

[0111] In this way, the noise caused by the stray capacitances C11 and C12 is considered the normal-mode noise. Therefore, a filter circuit composed of the choke coil 89, which is a normal-mode coil, and the capacitors 87 and 88 is applicable to reduce the noise induced by the stray capacitances caused by C11 and C12. Furthermore, a configuration for reducing common-mode noise and the like can be omitted. Furthermore, by reducing the common-mode noise and reducing the noise leakage to the outside of the drive unit 1 via the motor housing 11 and the frame member 20, radio noise is also reduced.

[0112] Specifically, in the present embodiment, the aluminum anodizing for insulation covers the entire motor housing 11, except for the conductive portion between the housing member and the controller support member (i.e., the frame member 20). Consequently, a path from the motor housing 11 to the power supply ground line 500 via the frame member 20, the substrate 41, and the power supply connector 96 has a lower impedance compared to a path from the motor housing 11 to a vehicle body ground. Accordingly, the common-mode noise leaking to the outside of the drive unit 1 via the motor housing 11 and the frame member 20 is further reduced.

[0113] Furthermore, in order to minimize the impedance of the path from the motor housing 11 to the power supply ground line 500, the frame securing screw 38 and the substrate securing screw 49 for the noise propagation path are preferably positioned to have the shortest distance.

[0114] The drive unit 1 comprises, as described in more detail above, the motor 10, the frame member 20, the ECU 40, and the power supply connector 96. The motor 10 comprises the stator 12, the rotor 15, and the shaft 16. The stator 12 has the first and second winding groups 13, 14 wound thereon. The rotor 15 is rotatably arranged within the stator 12. The shaft 16 rotates together with the rotor 15. The frame member 20 is arranged at one end of the motor 10.

[0115] The ECU 40 includes the substrate 41, the heat generating element 70 and the electronic components.

[0116] The substrate 41 is attached to the frame member 20. The heat-generating element 70 is attached to the heat-generating element attachment surface 42, which is located on a side of the substrate 41 facing the frame member 20, and is configured to dissipate heat to the frame member 20. The electronic components, including the microcomputer 81, the capacitors 86, 87, and the choke coil 89, are mounted on the electronic component attachment surface 43, which is another side of the substrate 41 facing away from the frame member 20.

[0117] The power supply connector 96 connects the substrate 41 and the battery 109. Furthermore, the power supply ground line 500 connected to the ground terminal of the battery 109 and the frame member 20 are conductively connected via the substrate 41 and the power supply connector 96.

[0118] In the present embodiment, the frame member 20 is connected to the power supply ground line 500 via the substrate 41 and the power supply connector 96. Consequently, the noise caused on the path provided by the stray capacitance C12 between the frame member 20 and the substrate 41 is collected by the power supply ground line 500 via the power supply connector 96, and the noise caused by the stray capacitance C12 is considered normal-mode noise. Specifically, the noise that would otherwise induce common-mode noise is "trapped" as normal-mode noise to the battery 109 in the present embodiment.

[0119] Consequently, based on the reduction in common-mode noise, the common-mode noise reduction scheme or configuration is simplified or omitted. Furthermore, the radio noise that would otherwise propagate from the control unit 1 via the frame element 20 to the on-board radio is reduced.

[0120] The electronic components mounted on the electronic component mounting surface 43 include capacitors 86 and 87 and choke coil 89, which form a filter circuit. Choke coil 89 is a normal-mode coil for reducing normal-mode noise. Consequently, normal-mode noise in the drive unit 1 is appropriately reduced.

[0121] The motor 10 further comprises a housing element with the cylinder part 114, which is arranged radially outside the stator 12, ie radially further away than from the central axis O of the motor 10 to the stator 12.

[0122] The cylinder part 114 and the power supply ground line 500 are connected via the frame member 20, the substrate 41 and the power supply connector 96 for electrical conductivity therebetween.

[0123] Through such a connection, the stray capacitance C11 caused in the air gap between the motor section and the housing is electrically connected to the power supply ground line 500, and the noise resulting from the stray capacitance C11 is considered normal-mode noise. Specifically, the noise due to the stray capacitance C11, which would otherwise be considered common-mode noise, is collected by the battery 109 as normal-mode noise. This further reduces the common-mode noise.

[0124] In the present embodiment, the motor housing 11 and the frame element 20 comprise separate bodies. The first contact surface 118, which is a surface in the motor housing 11 for contacting the frame element 20, and the second contact surface 268, which is a surface in the frame element 20 that contacts the motor housing 11, are conductively connected to each other via a surface contact.

[0125] When the motor housing 11 and the frame member 20 are provided as separate bodies, the frame member 20 can easily undergo a heat dissipation process or treatment for easier heat dissipation from the heat generating element 70. Furthermore, by providing the surface contact for connection between the motor housing 11 and the frame member 20, a "safe" electrical connection can be established between the two, whereby the noise caused by C11, C12 can be safely collected as the normal mode noise, which would otherwise be regarded as the common mode noise, and whereby the noise leakage to the outside of the drive unit 1 can be further reduced.Furthermore, the motor housing 11, which provides a housing for the drive unit 1, and the frame member 20 are configured to be conductively connected to each other, and the noise caused by C11 and C12 is collected by the battery 109, thereby reducing the wiring for connecting the stray capacitances C11 and C12 to the battery 109. That is, the number of components in the drive unit 1 is reduced.

[0126] The motor housing 11 and the frame member 20 are rigidly fastened in an electrically conductive manner by the frame locking screw 38. By fastening or fixing the motor housing 11 and the frame member 20 via the frame locking screw 38, conduction is securely established between the motor housing 11 and the frame member 20 via the axial force exerted by the frame locking screw 38. Furthermore, the frame locking screw 38 constructed of a conductive material further facilitates the electrical connection between the two, that is, the frame locking screw 38 constructed of the conductive material thickens the noise collecting path to the battery 109 for collecting the noise from the stray capacitances C11 and C12, whereby the noise leaking from the drive unit 1 can be further reduced.

[0127] In addition, a plurality of frame securing screws 38 are provided at equal intervals so as to uniformly reduce the impedance between the motor housing 11 and the frame member 20.

[0128] In the motor housing 11, the insulation process or insulation treatment is performed for a portion other than the conduction part between the housing 11 and the frame member 20. In such a configuration, the path carrying the common-mode noise has a high impedance so as to reduce the noise, ie, the common-mode noise leaking from the drive unit 1.

[0129] The electronic components, such as the heat-generating element, the microcomputer, and the like, are arranged in the projection area that describes a silhouette of the cylindrical part 114 of the motor 10, ie, the motor housing 11, in the axial direction. This appropriately reduces the volume of the drive unit 1 in the radial direction.

[0130] The drive unit 1 of the present embodiment is applied to the electric power steering device 8. More specifically, the electric power steering device 8 is equipped with the drive unit 1 and the reduction gear 9 for transmitting the torque output from the motor 10 to the steering column 102, driving the steering column 102 with the torque of the motor 10, and assisting a steering operation of the steering wheel 101 by the driver.

[0131] The drive unit 1 of the present embodiment includes the motor 10 and the ECU 40 coaxially arranged along the axis of the drive unit 1 to reduce the volume / size, and is configured to have a slim shape, that is, to have the entire device substantially in the engine section, which is a projection / silhouette of the cylinder part 114 in the axial direction. Thus, the drive unit 1 is practical, that is, easy to install in a small space under the hood. Furthermore, the leakage of noise from the drive unit 1 is reduced, thereby reducing radio noise affecting an on-vehicle radio unit.

[0132] Furthermore, the drive unit 1 of the present embodiment includes the O-ring 39 provided at a position between the motor housing 11 and the frame member 20, and the frame member 20 and the cover member 90 combined using an adhesive to realize a waterproof structure. Thus, the drive unit 1 can be installed in, for example, an engine compartment and suitably used in a rack-assist type electric power steering apparatus. (Second embodiment)

[0133] The control unit according to a second embodiment of the present invention is shown in the Fig. 13 to 16 shown. Fig. 13 shows a sectional view along the line XIII-XIII in the Fig. 15.

[0134] As for the drive unit 2 of the present embodiment, a motor 210 as a rotating electric machine and the ECU 40 as a controller are arranged in one body. The motor 210 includes a motor housing 211 and a frame member 230, which are different from those in the above-described embodiment.

[0135] The motor housing 211 includes, for example, a bottom portion 220 and a cylinder portion 214, and has a cylindrical shape with a closed bottom made of metal, such as aluminum, for thermal conductivity. In the present embodiment, the bottom portion 220 faces the ECU 40, and the other end, or an opposite side, is an opening of the cylinder portion 214.

[0136] A mounting lug 216 for mounting the frame element 230 is arranged around the opening of the cylinder part 214, i.e., projecting outward in the radial direction. Furthermore, a screw hole 217 is drilled into the mounting lug 216. The mounting lug 216 is arranged at three positions at equal intervals.

[0137] A shaft hole 221, into which the other end 162 of the shaft 16 is inserted, is located substantially in the center of the bottom part 220. The other end 162 of the shaft 16 is inserted into the shaft hole 221. This exposes the magnet 18 provided at the other end 162 of the shaft 16 to face the ECU 40. Furthermore, the bearing 167 is fitted into the bottom part 220.

[0138] Furthermore, a motor wire insertion hole into which the motor wires 135 and 145 are inserted (not shown) is drilled in the bottom part 220. Through this, the motor wires 135 and 145 are led out to extend toward the ECU 40.

[0139] A substrate fixing boss (not shown) is formed on a bottom surface 225 of the bottom part 220, and the substrate 41 is fixed to the surface 225 via the substrate fixing screw 49. The ground pattern on the substrate 41 and the motor housing 211 are firmly connected by the axial force of the substrate fixing screw 49, thereby electrically connecting each other.

[0140] As a result, the motor housing 211 is electrically connected to the power supply ground line 500 via the substrate securing screw 49, the substrate 41 and the power supply connector 96.

[0141] Furthermore, the heat generating element 70 mounted on the heat generating element mounting surface 42 of the substrate 41 can dissipate heat from a back surface toward the bottom surface 225 of the bottom part 220 via the thermal grease.

[0142] An adhesive groove 226 is provided radially outside, ie, at an edge, of the bottom surface 225, which corresponds to an outer side of the substrate 41. The cover member 90 is fixed to the motor housing 211 by the insertion portion 921 of the cover member 90, which is inserted into the adhesive groove 226 and secured with the adhesive. The cover member 90 is formed integrally with the connectors 96 and 97, similar to the embodiment described above.

[0143] Further, on the bottom surface, a receiving groove (not shown) is provided, the groove receiving a tip of the power supply connector terminal 962 and a tip of the signal connector terminal 972 which are inserted therein to prevent a short circuit between the terminals 962 and 972 and the motor housing 211.

[0144] A frame member 230 is constructed of metal, such as aluminum, and inserted into the cylinder part 214 to close the opening of the motor housing 211.

[0145] A shaft hole 231, into which one end 161 of the shaft 16 is inserted, is drilled substantially in the center of the frame member 230. Furthermore, the bearing 166 is fitted into the frame member 230.

[0146] The frame member 230 has a mounting lug 233 projecting radially outward at positions (i.e., three positions in the present embodiment) corresponding to the mounting lug 216. The mounting lug 233 has a through hole 234 drilled therein. A frame locking screw 238 is inserted into the through hole 234 and screwed into the screw hole 217. This secures the frame member 230 to the motor housing 211.

[0147] On an outer periphery of the frame member 230 closer to the bottom part 220 than the mounting lug 233, an O-ring groove 235 is provided, in which an O-ring 39 is arranged. The O-ring 39 is enclosed by the frame member 230 and the cylinder part 214. Such a structure prevents water and the like from penetrating into the inside of the motor 210.

[0148] In the present embodiment, the bottom part 220 of the motor housing 211 is arranged to face the ECU 40, and the substrate 41 is fixed on the bottom part 220 so that the heat-generating element 70 can dissipate heat from the back side. Specifically, according to the present embodiment, the bottom part 220 corresponds to the "controller holding member," and the bottom part 220 provides the following functions: an outline defining function for defining an outline of the motor 210, a holding function for holding the ECU 40, and a heat sink function for dissipating heat, i.e., serving as a heat sink, from the heat-generating element 70. This reduces the number of components and the volume of the drive unit 2 compared to a case where a heat sink is separately provided.

[0149] Furthermore, when heat of the heat generating element 70 is dissipated to the bottom part 220 formed integrally with the cylinder part 214, the dissipated heat is more easily conducted from the bottom part 220 to the cylinder part 214, compared with heat dissipation to the frame member 20 provided as a separate component from the motor housing 11, which causes resistance in heat conduction, that is, the size of a heat dissipation area is larger in the present embodiment, thereby dissipating heat highly efficiently.

[0150] The motor housing 211 is connected to the power supply ground line 500 via the substrate securing screw 49, the substrate 41, and the power supply connector 96. Consequently, the stray capacitance C21 between the motor section and the cylinder part 214 of the motor housing 211 and the stray capacitance C22 between the bottom part 220 of the motor housing 211 and the substrate 41 are connected to the power supply ground line 500 via the substrate 41. In this way, the noise caused by the stray capacitances C21 and C22 is considered normal mode noise, thereby achieving the same effect as in the above-described embodiment.

[0151] The stray capacitances C21 and C22 correspond to the stray capacitances C11 and C12 in the Fig. 12 and are not shown in the drawings.

[0152] In the present embodiment, the cylinder part 214 of the motor housing 211 and the bottom part 220 connected to the substrate 41 are integrally formed. Consequently, compared with the case where the cylinder part 214 and the bottom part 220 are provided separately, the impedance of the path from the cylinder part 214 to the power supply ground line 500 is reduced, thereby reducing noise leaking to the outside of the drive unit 2.

[0153] Furthermore, by subjecting the frame member 230 to the aluminum anodizing treatment, a path from the motor housing 211 via the substrate 41 and the power connector 96 to the power ground line 500 has a lower impedance compared to a path from the motor housing 211 to the vehicle body ground. Consequently, the common-mode noise leaking outside the drive unit 2 is further reduced.

[0154] In the present embodiment, the bottom part 220 serving as the controller holding member is formed integrally with the cylinder part 214.

[0155] As a result, the impedance between the cylinder part 214 and the bottom part 220 and the noise leaking outside the drive unit 2 are reduced. Furthermore, the thermal conductivity resistance between the bottom part 220 and the cylinder part 214 is reduced, and the heat dissipation area for heat dissipation from the heat-generating element 70 is increased, thereby efficiently dissipating heat from the heat-generating element 70. Furthermore, the same effects as in the above-described embodiment can also be achieved. (Other embodiments)

[0156] Although the present invention has been described above in connection with the preferred embodiments thereof with reference to the accompanying drawings, it should be appreciated that various changes and modifications will be apparent to those skilled in the art. (a) Controller holder

[0157] According to the first embodiment described above, the frame member is fixed to the motor housing by the frame locking or frame fixing screw.

[0158] According to the further embodiments, as long as the frame element and the motor housing are conductively connected, the connection can be made not only via the screw, but also by another element.

[0159] Furthermore, the number of fastening lugs is not limited to three, but can be more or fewer than three, whereby a symmetrical arrangement is not absolutely necessary.

[0160] Furthermore, in other embodiments, the frame member may be press-fitted to the motor housing. In such a case, the inner peripheral wall of the motor housing and the outer peripheral wall of the frame member may be matingly connected, and the conductivity between the motor housing and the frame member may be established as a surface contact between the two. In such a case, the inner peripheral surface of the motor housing is synonymous with the "first contact surface," and the outer peripheral surface of the frame member is synonymous with the "second contact surface." Press-fitting the frame member contributes to reducing the number of components and the product size along a diameter thereof.

[0161] Furthermore, if the bottom of the motor housing forms the "controller support member," as described in the second embodiment, it is not necessary to establish conduction between the motor housing and the frame member. Rather, the combination and attachment between the motor housing and the frame member can be implemented in any desired manner.

[0162] Furthermore, in the embodiment described above, the control unit comprises the motor housing, which has a cylinder part.

[0163] However, in other embodiments, the motor housing may be omitted. Specifically, a front frame end provided on one side of the motor and a rear frame end provided on the other side of the motor to hold the stator may be fixed to each other via a through-bolt. In such a case, the rear frame end corresponds to the "controller holding member," and the stator corresponds to the "cylindrical part of the rotating electrical machine." If the motor housing is omitted, the stator may be considered a "cylindrical part of the rotating electrical machine," and a projection along the stator axis may be considered a "motor portion." Specifically, the cylindrical part of the rotating electrical machine may be the cylindrical part of the motor housing or the stator. (b) Attaching the substrate

[0164] According to the embodiment described above, the substrate is fixed to the bottom of the frame member or to the motor housing by the substrate securing screw.

[0165] According to the further embodiments, as long as the fastening element can fix the ground pattern of the substrate to the frame element or the motor housing in a conductive manner, the fastening element does not necessarily have to be a screw, but any other element is conceivable. (c) ECU

[0166] According to the embodiment described above, the ECU has the two pairs of inverters and relays.

[0167] According to other embodiments, the inverter and the power relay may be provided as three or more sets. Furthermore, the power relay and the reverse-connected protective relay, which are constructed of the semiconductor device in the above-described embodiment, may be replaced with the mechanical power relay. In such a case, the reverse-connected protective relay may be omitted. Furthermore, when the power relay is provided as the mechanical relay, this relay may preferably be mounted on the electronic component mounting surface of the substrate.

[0168] According to the further embodiments, the arrangement of the electronic components on the substrate can be realized in any form different from that in the embodiment described above.

[0169] According to the embodiment described above, the metal piece is fixed on the substrate for connection to the motor lead, and the substrate and the motor lead are connected by press-fitting.

[0170] According to the further embodiments, soldering or any other method other than press-fitting may be used for the connection between the substrate and the motor lead. (d) Connector part

[0171] In the embodiment described above, the connector part has a power supply connector and two signal connectors.

[0172] According to further embodiments, one or both of the power supply connector and the signal connector may be provided in multiples. These connectors may be provided in separate bodies or in a single-body combination.

[0173] The connector may be structured such that its opening is aligned with the axis of the drive unit, or may be structured such that its opening is aligned with the radial direction. Furthermore, the connector, which in the above embodiment is arranged on the side of the substrate facing away from the motor, may also be arranged on the motor side of the substrate in the other embodiments.

[0174] Furthermore, the connector, which is formed integrally with the cover member in the above-described embodiment, may also be formed separately from the cover member. (e) Cover element

[0175] According to the embodiment described above, the cover element is attached to the frame element by means of adhesive.

[0176] According to the further embodiments, the control unit can be attached to the frame element in any other way, such as using a screw or the like. (f) Housing element

[0177] According to the above-described embodiment, the housing member undergoes the treatment for anodizing aluminum at a portion different from the capacitor for contacting the frame member.

[0178] According to the further embodiments, the insulation of the housing element can be realized in any manner different from the above or can be omitted.

[0179] Furthermore, the frame element may have undergone an insulation treatment for a portion different from the contact surface for contacting the housing element. (g) Control unit

[0180] According to the embodiment described above, the rotating electrical machine is a brushless three-phase motor.

[0181] According to the further embodiments, the rotating electric machine may be any motor other than the brushless three-phase motor.

[0182] Furthermore, the rotating electrical machine may be not only a motor (i.e., an electric motor), but also a dynamo / generator or a motor-generator that serves as both a motor and a generator. Furthermore, the winding may be provided not only in two systems, but also in three or more than three systems.

[0183] According to the above-described embodiment, the drive unit is applied to the electric power steering apparatus.

[0184] According to the further embodiments, the drive unit can be applied to devices other than the electric power steering device.

[0185] Such changes, modifications and summary schemes are to be understood as being included within the scope of the present invention as set forth in the appended claims.

Claims

[1] Control unit (1, 2) with: - a rotating electrical machine (10, 210) comprising: (i) a stator (12) having a winding (13, 14) wound on the stator and a shaft (16) rotating within the stator, (ii) a rotor (15) rotatable relative to the stator, (iii) a motor housing (11), and (iv) a frame member (20) attached to the motor housing (11); - a controller holding element (20, 220) arranged above the shaft; - a controller (40) comprising: - a substrate (41) attached to the controller support member, the substrate including: (i) an upwardly facing electronic component mounting surface (43), and (ii) a downwardly facing heat generating element mounting surface (42), - a heat generating element (70) attached to the downwardly facing heat generating element attachment surface (42) to enable heat dissipation from the heat generating element to the controller holding element, and - electronic components (81, 86, 87, 89) mounted on the upwardly facing electronic component mounting surface (43) of the substrate, wherein the controller is arranged above the controller holding member; - a power supply connector (96) configured to electrically connect the substrate to a power source (109); and - a substrate securing screw (49) forming an electrical path from the substrate (41) to the frame element (20) so that a stray capacitance (C12) between the substrate (41) and the frame element (20) is reduced or eliminated, wherein the power supply connector (96) is arranged above the controller, and wherein the power supply connector (96) is further configured to electrically connect the substrate to a ground line (500). [2] Control unit according to claim 1, characterized by , that - the electronic components comprise a capacitor (86, 87) serving as a filter circuit and a coil element (89); and - the coil element has a normal-mode coil that reduces normal-mode noise. [3] Control unit according to claim 1 or 2, characterized by , that - the rotating electrical machine further comprises a housing element (11, 211) with a cylinder part (114, 214) arranged radially outside the stator; and - the cylinder part and the ground line are conductively connected via the controller holding element, the substrate and the power supply connector. [4] Control unit according to claim 3, characterized by , that - the housing element (11) and the controller holding element (20) are provided as separate bodies; and - the housing element has a surface contact with the controller holding element, wherein it establishes the conductivity between the housing element and the controller holding element by the surface contact between a contact surface (118) of the housing element and a contact surface (268) of the controller holding element. [5] Control unit according to claim 4, characterized by that the housing element and the controller holding element are conductively fastened to one another by a fastening element (38). [6] Control unit according to claim 5, characterized by that the fastening element is provided in several parts at several positions at the same interval. [7] Control unit according to claim 3, characterized by that the controller holding element (220) is formed integrally with the cylinder part (214). [8] Control unit according to one of claims 3 to 7, characterized by that the housing element and / or the controller holding element have undergone an insulation treatment at positions other than a conduction part (118, 218) between the housing element and the controller holding element. [9] Control unit according to one of claims 1 to 8, characterized by that the heat generating element and the electronic components are arranged within a projection area of the cylinder part (114, 214) of the rotating electrical machine in an axial direction. [10] Electric power steering device (8) with: - a control unit with: - a rotating electrical machine (10, 210) comprising: (i) a stator (12) having a winding (13, 14) wound on the stator and a shaft (16) rotating within the stator, (ii) a rotor (15) rotatable relative to the stator, (iii) a motor housing (11), and (iv) a frame member (20) attached to the motor housing (11); - a controller holding element (20, 220) arranged above the shaft; - a controller (40) comprising: - a substrate (41) attached to the controller support member, the substrate including: (i) an upwardly facing electronic component mounting surface (43), and (ii) a downwardly facing heat generating element mounting surface (42), - a heat generating element (70) attached to the downwardly facing heat generating element attachment surface (42) to enable heat dissipation from the heat generating element to the controller holding element, and - electronic components (81, 86, 87, 89) mounted on the upwardly facing electronic component mounting surface (43) of the substrate, wherein the controller is arranged above the controller holding member; - a power supply connector (96) configured to electrically connect the substrate to a power source (109); and - a substrate securing screw (49) forming an electrical path from the substrate (41) to the frame element (20) so that a stray capacitance (C12) between the substrate (41) and the frame element (20) is reduced or eliminated, wherein the power supply connector (96) is arranged above the controller, wherein the power connector (96) is further configured to electrically connect the substrate to a ground line (500); and - wherein a power transmission section (9) transmits a torque from the rotating electric machine to a control object (102) so that the torque from the rotating electric machine drives the control object to assist a steering operation of a steering wheel (101) by a driver.

Images