ELECTRIC WORK MACHINE

Abstract

One aspect of the present disclosure provides for an electric machine (1) comprising: a motor (20); a printed circuit board (11); a first semiconductor switch (Q1); and a first metal plate (100). The motor (20) is driven by receiving electrical power from a power supply (12). The first semiconductor switch (Q1) is located on the printed circuit board (11), has a first metal surface (46) and a first mounting surface (48), and is electrically coupled to the power supply (12) and to the motor (20). The first mounting surface (48) is located opposite the first metal surface (46) and is opposite the printed circuit board (11). The first metal plate (100) has: a first plate surface (100A) soldered to the first metal surface (46); and a second plate surface (100B) opposite the first plate surface (100A).

Description

[0001] The present disclosure relates to an electric working machine with semiconductor switches.

[0002] A power tool disclosed in Japanese patent no. 5512110 comprises a tool bit, a motor that generates a driving force for driving the tool bit, and a control circuit for driving the motor. The control circuit has six switching devices.

[0003] In recent years, the output power of electric power tools, such as power tools, has increased. Consequently, the current flowing through the motor and control circuitry of the electric power tool has also increased. This has led to an increase in heat generation within the switching devices of the control circuitry. Therefore, it is necessary to dissipate the heat generated in these devices efficiently.

[0004] It is desirable that one aspect of the present disclosure is capable of providing an electric working machine with improved heat dissipation efficiency of semiconductor switches.

[0005] In the present revelation, ordinal numbers, such as "first" and "second," are intended solely to distinguish the elements from one another and are not meant to restrict the order and / or number of elements. Thus, the first element can be called the second element, and similarly, the second element can be called the first element. Furthermore, the first element can be provided for without the second element, and similarly, the second element can be provided for without the first element.

[0006] One aspect of the present disclosure provides for an electric machine comprising a motor, a printed circuit board, a first semiconductor switch, and a first metal plate. The motor is configured to receive electrical power from a power supply, thereby driving it. The first semiconductor switch is located on the printed circuit board, has a first metal surface and a first mounting surface, and is electrically coupled to the power supply and the motor. The first mounting surface is opposite the first metal surface and faces the printed circuit board. The first metal plate has: a first plate surface that is soldered to the first metal surface; and a second plate surface opposite the first plate surface.

[0007] In such an electrical machine, the first semiconductor switch has the first metal surface, and this metal surface is soldered to the first metal plate. This means that the heat dissipation path from the first semiconductor switch to the first metal plate is made of metal, which has a higher thermal conductivity than resin or any other material. Thus, the heat generated in the first semiconductor switch is efficiently conducted via the solder material to the first metal plate and dissipated by it. This improves the heat dissipation efficiency of the first semiconductor switch.

[0008] Another aspect of the present disclosure provides a method for assembling a control unit for controlling a motor of an electric machine. This method comprises: mounting a semiconductor switch of the control unit onto a printed circuit board of the control unit, the semiconductor switch having a mounting surface and a metal surface opposite the mounting surface, which mounting surface is opposite the printed circuit board; and soldering a metal plate to the metal surface.

[0009] According to such a method, the heat dissipation efficiency of the semiconductor switch can be improved.

[0010] Examples of embodiments of the present disclosure are described below with reference to the accompanying drawings, in which: Fig. 1 is a view showing the appearance of an electric machine according to the first and second embodiments; Fig. 2 is a diagram showing an electrical configuration of the electric machine according to the first and second embodiments; Fig. 3 is a top view showing a printed circuit board on which a control circuit according to the first embodiment is mounted; Fig. Figure 4 shows a longitudinal cross-sectional view of the printed circuit board according to the first embodiment; Fig. Figure 5 shows a longitudinal cross-sectional view of the printed circuit board according to the first embodiment in a modified example; Fig. 6 is a view showing a first circuit surface of a printed circuit board on which a control circuit according to the second embodiment is mounted; Fig. 7 is a view showing a second circuit surface of the printed circuit board according to the second embodiment; Fig. 8 is a view showing the appearance of a metal component to be inserted into the printed circuit board according to the second embodiment, Fig. 9 is a view showing an electrical coupling between a source terminal of a first semiconductor switch and a drain terminal of a fourth semiconductor switch according to the second embodiment; Fig. 10 is a view showing a longitudinal cross-section of the printed circuit board according to the second embodiment; Fig. 11 is a longitudinal partial cross-sectional view of a control unit according to another embodiment. [Overview of embodiments]

[0011] One embodiment can provide an electric machine with at least one of the following: - Feature 1: a motor designed to receive electrical power from a power supply so that it is driven by it; - Feature 2: a printed circuit board; - Feature 3: a first semiconductor switch on the circuit board, which has a first metal surface and a first mounting surface and is electrically coupled to the power supply and to the motor; - Feature 4: the first mounting surface is opposite the first metal surface and faces the printed circuit board; and - Feature 5: a first metal plate with: a first plate surface that is soldered to the first metal surface; and a second plate surface opposite the first plate surface.

[0012] In the electrical machine with at least features 1 to 5, the first semiconductor switch has a metal surface, and this metal surface is soldered to the first metal plate. This means that the heat dissipation path from the first semiconductor switch to the first metal plate is made of a metal with a higher thermal conductivity than resin or any other material. Therefore, the heat generated in the first semiconductor switch is efficiently conducted to the first metal plate via the solder and dissipated by the first metal plate. This improves the heat dissipation efficiency of the first semiconductor switch.

[0013] An embodiment may, in addition to or instead of at least one of the features 1 to 5, have at least one of the following: - Feature 6: the first plate surface has a first metal foil; and - Feature 7: the first metal foil is soldered to the first metal surface.

[0014] In the electrical machine with at least features 1 to 7, the first plate surface has the first metal foil. Thus, even if the first metal plate contains metal that is difficult to solder, the first metal foil can be soldered to the first metal surface; in other words, the first metal plate can be connected to the first semiconductor switch.

[0015] An embodiment may, in addition to or instead of at least one of the features 1 to 7, have at least one of the following: - Feature 8: a second semiconductor switch on the circuit board, which is different from the first semiconductor switch, has a second metal surface and a second mounting surface, and is electrically coupled to the power supply and the motor; - Feature 9: the second mounting surface is opposite the second metal surface and faces the circuit board; and - Feature 10: the first plate surface is soldered to the first metal surface and to the second metal surface.

[0016] In the electrical machine with at least features 1 to 5 and 8 to 10, the first metal plate is soldered to the first metal surface of the first semiconductor switch and to the second metal surface of the second semiconductor switch. This allows the heat generated in the first and second semiconductor switches to be efficiently dissipated through the first metal plate.

[0017] An embodiment may, in addition to or instead of at least one of the features 1 to 10, have at least one of the following: - Feature 11: a second semiconductor switch on the circuit board, which is different from the first semiconductor switch, has a second metal surface and a second mounting surface, and is electrically coupled to the power supply and the motor; - Feature 12: the second mounting surface is opposite the second metal surface and faces the circuit board; - Feature 13: the first plate surface has a second metal foil; - Feature 14: the first plate surface has a first insulating section located between the first metal foil and the second metal foil, as well as on the first plate surface; and - Feature 15: the second metal foil is soldered to the second metal surface.

[0018] In the electrical machine with at least features 1 to 7 and 11 to 15, the first plate surface has the second metal foil. Thus, the second metal foil can be soldered to the second metal surface; in other words, the first metal plate can be connected to the second semiconductor switch. Furthermore, since the first insulating section is located between the first and second metal foils, a short circuit between the first and second semiconductor switches is prevented.

[0019] An embodiment may, in addition to or instead of at least one of the features 1 to 15, have at least one of the following: - Feature 16: a third semiconductor switch on the circuit board, which is different from the first semiconductor switch and the second semiconductor switch, has a third metal surface and a third mounting surface, and is electrically coupled to the power supply and to the motor; - Feature 17: the third mounting surface is opposite the third metal surface and faces the circuit board; - Feature 18: the first plate surface has a third metal foil; - Feature 19: the first plate surface has a second insulating section located between the second metal foil and the third metal foil, as well as on the first plate surface; and - Feature 20: the third metal foil is soldered to the third metal surface.

[0020] In the electrical machine with at least features 1 to 7 and 11 to 20, the first plate surface has the third metal foil. Thus, the third metal foil can be soldered to the third metal surface; in other words, the third semiconductor switch can be connected to the first metal surface. Furthermore, since the second insulating section is located between the second and third metal foils, a short circuit between the second and third semiconductor switches is prevented.

[0021] An embodiment may, in addition to or instead of at least one of the features 1 to 20, have at least one of the following: - Feature 21: the first semiconductor switch, the second semiconductor switch, and the third semiconductor switch are arranged in a row on the circuit board; and - Feature 22: the first metal plate covers the first metal surface, the second metal surface, and the third metal surface.

[0022] In the electric machine with at least features 1 to 7 and 11 to 22, the first to third semiconductor switches are arranged in a row on the circuit board. This allows the first to third semiconductor switches to be soldered to a single metal plate. This, in turn, makes it possible to reduce the number of components in the electric machine.

[0023] An embodiment may additionally include, or instead of, at least one of the features 1 to 22: - Feature 23: the first semiconductor switch, the second semiconductor switch and the third semiconductor switch form at least part of a control circuit for controlling the motor.

[0024] In the electric machine with at least features 1 to 7, 11 to 20, and 23, the first to third semiconductor switches form at least part of the control circuit. Thus, in a case where a large current has flowed through the control circuit, the heat generated in the first to third semiconductor switches can be efficiently dissipated by the first metal plate.

[0025] An embodiment may, in addition to or instead of at least one of the features 1 to 23, have at least one of the following: - Feature 24: a second semiconductor switch on the circuit board, which is different from the first semiconductor switch, has a second metal surface and a second mounting surface, and is electrically coupled to the power supply and to the motor; - Feature 25: the second mounting surface is opposite the second metal surface and faces the circuit board; and - Feature 26: a second metal plate that is different from the first metal plate and is soldered to the second metal surface.

[0026] In the electric machine with at least features 1 to 5 and 24 to 26, the second metal plate, which differs from the first metal plate, is soldered to the second semiconductor switch. Therefore, the first and second semiconductor switches do not need to be arranged side by side. This, in turn, increases the degree of freedom for the locations where the first and second semiconductor switches are mounted.

[0027] An embodiment may additionally include, or instead of, at least one of the features 1 to 26: - Feature 27: a heat dissipation component in direct or indirect contact with the second plate surface.

[0028] In the electrical machine with at least features 1 to 5 and 27, the heat dissipation component is in direct or indirect contact with the second plate surface. Thus, the heat generated in the first semiconductor switch is conducted via the solder material and the first metal plate to the heat dissipation component and is then dissipated by the heat dissipation component. This allows for a further improvement in the heat dissipation efficiency of the first semiconductor switch.

[0029] An embodiment may, in addition to or instead of at least one of the features 1 to 27, have at least one of the following: - Feature 28: the circuit board has a rectangular shape; - Feature 29: the first metal plate has a rectangular shape; - Feature 30: the first semiconductor switch, the second semiconductor switch, and the third semiconductor switch are arranged along a longitudinal direction of the printed circuit board; and - Feature 31: a longitudinal direction of the first metal plate is aligned with the longitudinal direction of the printed circuit board.

[0030] In the electric machine with at least features 1 to 7, 11 to 22, and 28 to 31, the first to third semiconductor switches are arranged along the longitudinal directions of the circuit board and the first metal plate. This allows the motor control unit to be reduced in size.

[0031] An embodiment may additionally include, or instead of, at least one of the features 1 to 31: - Feature 32: the heat dissipation component has two or more fins.

[0032] In the electric working machine with at least features 1 to 5, 27 and 32, the heat dissipation efficiency of the first semiconductor switch can be further improved.

[0033] An embodiment may, in addition to or instead of at least one of the features 1 to 32, have at least one of the following: - Feature 33: the first metal plate has a metal base with the second plate surface; and - Feature 34: the first metal plate has an insulating layer that is connected to the metal base and to the first metal foil.

[0034] In the electric working machine with at least features 1 to 5, 33 and 34, a current flow from the first semiconductor switch to the metal base is prevented.

[0035] At least one of the first through third semiconductor switches may be in a surface-mount package, specifically a top-cooled package or a dual-sided cooled package. Examples of a top-cooled package include, but are not limited to, a TO-terminated top-cooled (TOLT) package. Examples of a dual-sided cooled package include, but are not limited to, a dual-sided cooled small outline (DSOP) package. Examples of the first through third semiconductor switches include, but are not limited to, a metal-oxide-semiconductor field-effect transistor (MOSFET), a junction field-effect transistor (JFET), an insulated-gate bipolar transistor (IGBT), a bipolar transistor, a solid-state relay (SSR), and a thyristor.

[0036] Examples of electric work machines include various electrical devices used in workplaces for DIY, manufacturing / production, horticulture, gardening, construction, etc., particularly electric power tools for masonry, metalworking, and woodworking; work machines for gardening; and devices for creating a work environment, specifically electric blowers, electric hammers, electric hammer drills, electric drills, electric screwdrivers, electric ratchet wrenches, electric grinders, electric polishers, electric circular saws, electric reciprocating saws, electric jigsaws, electric cutting devices, electric chainsaws, electric planers, electric nailers (including electric staplers), electric hedge trimmers, electric lawn mowers, electric string trimmers, electric brush cutters / grass trimmers, electric cleaning devices, and electric sprayers.Electric spreaders, electric dusters (or electric dust extractors / vacuum cleaners), electric bicycles (or e-bikes) and battery-powered wheelbarrows (or battery-powered carts).

[0037] One embodiment may provide a method for assembling a control unit for controlling a motor of an electric machine, which method has at least one of the following features: - Feature 35: Mounting a semiconductor switch of the control unit on a circuit board of the control unit; - Feature 36: the semiconductor switch has a mounting surface and a metal surface opposite the mounting surface, and the mounting surface faces the printed circuit board; and - Feature 37: Soldering a metal plate to the metal surface.

[0038] According to the method with at least features 35 to 37, the heat dissipation efficiency of the semiconductor switch can be improved.

[0039] In one embodiment, features 1 to 37 can be combined in any combination.

[0040] In one embodiment, one of features 1 to 37 may be omitted. [Specific example implementation forms]

[0041] Certain exemplary embodiments are described below. These particular exemplary embodiments provide for an electric work machine 1 in the configuration of an electric chainsaw. The electric chainsaw is a type of garden tool. However, the electric work machine 1 of this type is merely an example, and the present disclosure can be applied to electric work machines in any configuration. [1. First embodiment]<1-1. Design of the electric work machine>

[0042] As in Fig. As shown in Figure 1, the electric machine 1 has a housing 2. The housing 2 is made of synthetic resin. The housing 2 accommodates a motor 20. The housing 2 also accommodates a control unit 25. The control unit 25 comprises: a printed circuit board 11; and a control circuit 21, which is mounted on the printed circuit board 11, both of which are described below.

[0043] The terms "upper", "lower", "front", "rear", "left", and "right" in the descriptions below are used solely to facilitate a basic understanding of the structure of the electric machine 1 and its components, and are not intended to restrict the orientations of the electric machine 1 and its components. The electric machine 1 and its components can be arranged in any orientation.

[0044] The electric machine 1 has a guide rail (a blade) 9. The guide rail 9 is a plate-shaped component. The guide rail 9 projects from the housing 2 in a forward direction of the electric machine 1.

[0045] The electric machine 1 includes a saw chain 9a as a tool. The saw chain 9a has several cutting elements that are connected to one another. The saw chain 9a is detachably attached to a circumferential edge of the guide bar 9. The saw chain 9a is coupled to a rotor shaft (not shown) of the motor 20 via a power transmission mechanism (not shown). The power transmission mechanism has a sprocket (not shown) designed to accommodate the saw chain 9a.

[0046] Thus, driving the motor 20 causes the saw chain 9a to move along the circumferential edge of the guide bar 9. This movement of the saw chain 9a enables the electric machine 1 to cut a workpiece.

[0047] The electric machine 1 has a battery mounting section 5. In the present embodiment, the battery mounting section 5 projects upwards from a rear part of the housing 2. The battery mounting section 5 is located where a battery pack 12 is detachably attached. The battery pack 12 is attached to a rear end face of the battery mounting section 5. The battery pack 12 comprises a rechargeable battery. In the present embodiment, the rechargeable battery is a lithium-ion battery, but this is not limited to the above. By being attached to the battery mounting section 5, the battery pack 12 can supply direct current power to the electric machine 1.

[0048] In another embodiment, the electric machine 1 can have a power cable instead of the battery mounting section 5. The electric machine 1 can draw AC power from an AC power supply, such as mains power (or AC mains current), via the power cable. The AC power drawn from the AC power supply can be converted into DC power or AC power within the electric machine 1 using different parameters.

[0049] The electric machine 1 has a hand guard 4. The hand guard 4 projects upwards from a front part of the housing 2.

[0050] The electric work machine 1 has a side handle 3A and a top handle 3B, which is positioned behind the hand guard 4. Either the side handle 3A or the top handle 3B can be omitted. The side handle 3A and the top handle 3B are made of synthetic resin.

[0051] The side handle 3A is a tubular component. The side handle 3A projects to the left from the left side of the housing 2. This allows a user of the electric work machine 1 to grasp the side handle 3A with their left hand from the rear of the electric work machine 1.

[0052] The upper handle 3B projects upwards from an upper part of the housing 2. A rear end of the upper handle 3B is connected to the battery mounting section 5, thus creating a space between the upper handle 3B and the housing 2. This allows the user to grasp the upper handle 3B by inserting their fingers through this space.

[0053] The electric work machine 1 has a push-button switch 7 on the lower section of the upper handle 3B. The push-button switch 7 is designed to be actuated (e.g., pulled) by the user to control the motor 20. Pulling the push-button switch 7 upwards by the user causes the motor 20 to be activated. Releasing the push-button switch 7 stops the motor 20 from being activated.

[0054] The electric work machine 1 has a push-button locking lever 8 on the upper section of the upper handle 3B. The user pushes the push-button locking lever 8 downwards to release the lock on the push-button switch 7. <1-2. Control unit>

[0055] As in Fig. As shown in Figure 2, the electric machine 1 has a control unit 10. The control unit 10 receives the DC power from a battery 12a within the battery pack 12 and controls the motor 20 so that the saw chain 9a is driven or stopped. In the present embodiment, the motor 20 is a brushless three-phase DC motor. In another embodiment, the motor 20 can be a brushless single-phase DC motor, a brushless two-phase DC motor, a brushless DC motor with four or more phases, a brushed motor, an AC motor, or a stepper motor.

[0056] The control circuit 10 comprises: the control unit 25 with a control circuit 21; a gate circuit 22; a control circuit 23 and a regulator 24.

[0057] The control circuit 21 is configured to (i) receive a DC motor current from the battery 12a, (ii) convert the received DC motor current into three-phase AC motor currents (i.e., U-phase, V-phase, and W-phase motor currents), and (iii) supply the three-phase AC motor currents to the three-phase windings of the motor 20. In particular, the control circuit 21 is a three-phase full-bridge inverter circuit with first to sixth semiconductor switches Q1 to Q6. In another embodiment, the control circuit 21 can be a full-bridge inverter circuit with a single phase, two phases, or four or more phases, or it can be a half-bridge inverter circuit.

[0058] Specifically, the first to sixth semiconductor switches Q1 to Q6 are FETs. More precisely, the first to sixth semiconductor switches Q1 to Q6 are N-channel MOSFETs. In another embodiment, at least one of the first to sixth semiconductor switches Q1 to Q6 can be a P-channel MOSFET, a JFET, an IGBT, a bipolar transistor, an SSR, or a thyristor.

[0059] In the control circuit 21, the first to third semiconductor switches, Q1 to Q3, are high-side switches. The first to third semiconductor switches, Q1 to Q3, are connected, respectively, to terminals U, V, and W of the motor 20 and to a power line (power line) Lp. The power line Lp is connected to a positive electrode of the battery 12a. In the control circuit 21, the fourth to sixth semiconductor switches, Q4 to Q6, are low-side switches. The fourth to sixth semiconductor switches, Q4 to Q6, are connected, respectively, to terminals U, V, and W of the motor 20 and to a ground line Ln. The ground line Ln is connected to a negative electrode of the battery 12a.

[0060] The first through sixth semiconductor switches, Q1 to Q6, have gate terminals 41, 51, 61, 71, 81, and 91; drain terminals 42, 52, 62, 72, 82, and 92; and source terminals 43, 53, 63, 73, 83, and 93. The gate terminals 41, 51, 61, 71, 81, and 91 of the first through sixth semiconductor switches, Q1 to Q6, are connected to the gate circuit 22. The drain terminals 42, 52, and 62 of the first through third semiconductor switches, Q1 to Q3, are connected to the current line Lp. The source terminals 63, 83, and 93 of the fourth through sixth semiconductor switches, Q4 to Q6, are connected to the ground line Ln. The source terminal 43 of the first semiconductor switch Q1 is connected to the drain terminal 72 of the fourth semiconductor switch Q4 and to a U-phase of the motor 20. The source terminal 53 of the second semiconductor switch Q2 is connected to the drain terminal 82 of the fifth semiconductor switch Q5 and to a V-phase of the motor 20.The source terminal 63 of the third semiconductor switch Q3 is coupled to the drain terminal 92 of the sixth semiconductor switch Q6 and to a W-phase of the motor 20.

[0061] The gate circuit 22 switches the first to sixth semiconductor switches Q1 to Q6 on or off according to control signals supplied by the control circuit 23, in order to supply the three-phase AC motor currents to the three-phase windings of the motor 20. This results in rotation of the motor 20.

[0062] The control circuit 23 includes a microcomputer (or microcontroller or microprocessor) not shown. In another embodiment, the control circuit 23 may include an additional microcomputer. In yet another embodiment, the control circuit 23 may include, instead of or in addition to the microcomputer, a graphics processing unit (GPU), hardwired logic, an application-specific integrated circuit (ASIC), an application-specific standard product (ASSP), a programmable logic device (PLD) (e.g., a field-programmable gate array (FPGA)), a discrete electronic component, and / or a combination thereof.

[0063] The regulator 24 is configured to (i) receive the DC power from the battery 12a and (ii) generate a power supply voltage Vcc. The power supply voltage Vcc is supplied to internal circuits of the control unit 10, including the control circuit 23.

[0064] The control unit 10 further comprises a load switch Q7 and a bootstrap 26. The load switch Q7 is arranged between the battery 12a and the control circuit 21 on the power line Lp to protect the control circuit 21 and / or the motor 20. The load switch Q7 is a semiconductor switch. In particular, the load switch Q7 is an N-channel MOSFET. In another embodiment, the load switch Q7 can be a P-channel MOSFET, a JFET, an IGBT, a bipolar transistor, or an SSR. In yet another embodiment, the load switch Q7 can be a mechanical relay. A gate terminal of the load switch Q7 is coupled to the control circuit 23 via the bootstrap 26. The load switch Q7 is kept switched on while the motor 20 is allowed to be driven.The motor current flowing through load switch Q7 can be greater than the motor current flowing through each of the first six semiconductor switches Q1 to Q6. The voltage applied to load switch Q7 can also be greater than the voltage applied to each of the first six semiconductor switches Q1 to Q6. Therefore, the rated voltage and current of load switch Q7 are higher than those of the first six semiconductor switches Q1 to Q6.

[0065] The control circuit 21 includes first and second thermistors 27 and 29. The first thermistor 27 is located near the first to third semiconductor switches Q1 to Q3 to measure the temperature close to these switches. The first thermistor 27 supplies the control circuit 23 with a temperature sensing signal indicating the measured temperature. The second thermistor 29 is located near the fourth to sixth semiconductor switches Q4 to Q6 to measure the temperature close to these switches. The second thermistor 29 supplies the control circuit 23 with a temperature sensing signal indicating the measured temperature. <1-3. Control unit><1-3-1. Examples>

[0066] The control unit 25 is used in relation to Fig. 3 and Fig. 4 described. The control unit 25 comprises: the printed circuit board 11; the control circuit 21, which is mounted on the printed circuit board 11; four elastic components 35; two metal plates 100; two heat dissipation components 200; and four externally threaded screws 400. Fig. Figure 3 shows the two metal plates 100, the two heat dissipation components 200, and the four externally threaded screws 400 in a transparent manner. In practice, the control circuit 21 on the circuit board 11 is covered by the two metal plates 100 and the two heat dissipation components 200.

[0067] The printed circuit board 11 (PCB) is a printed circuit board. The PCB 11 has a rectangular planar shape. In another embodiment, the PCB 11 can have a non-rectangular planar shape. The PCB 11 has a first circuit surface 11A and a second circuit surface 11B. The second circuit surface 11B is arranged opposite (in opposition to) the first circuit surface 11A.

[0068] The control circuit 21 includes the first to sixth semiconductor switches Q1 to Q6, the first and second thermistors 27 and 29, the U-phase connection 45, the V-phase connection 55 and the W-phase connection 65.

[0069] The first through sixth semiconductor switches, Q1 through Q6, are of a surface-mount type. In other words, the first through sixth semiconductor switches, Q1 through Q6, each have a surface-mount package. Specifically, the first through sixth semiconductor switches, Q1 through Q6, each have a top-cooled package, more precisely a TOLT package. The first through sixth semiconductor switches, Q1 through Q6, are of the same model, but are not restricted to being of the same model. The first through sixth semiconductor switches, Q1 through Q6, are arranged on the first circuit surface 11A. The first through third semiconductor switches, Q1 through Q3, are arranged in a row along a longitudinal direction (left-right) on the front side of the first circuit surface 11A, and the fourth through sixth semiconductor switches, Q4 through Q6, are arranged in a row along a longitudinal direction (left-right) on the rear side of the first circuit surface 11A.The first and fourth semiconductor switches, Q1 and Q4, are arranged side-by-side in a lateral direction (front-to-back). The second and fifth semiconductor switches, Q2 and Q5, are arranged side-by-side in a lateral direction (front-to-back). The third and sixth semiconductor switches, Q3 and Q6, are arranged side-by-side in a lateral direction (front-to-back).

[0070] The packages of the first to sixth semiconductor switches Q1 to Q6 are plate-shaped and have (i) first ends 46A, 56A, 66A, 76A, 86A and 96A and (ii) second ends 46B, 56B, 66B, 76B, 86B and 96B opposite the respective first ends. The drain terminals 42, 52, 62, 72, 82 and 92 of the first to sixth semiconductor switches Q1 to Q6 protrude from the respective first ends 46A, 56A, 66A, 76A, 86A and 96A. The gate terminals 41, 51, 61, 71, 81, and 91 of the first to sixth semiconductor switches Q1 to Q6 extend from their respective second ends 46B, 56B, 66B, 76B, 86B, and 96B. The source terminals 43, 53, 63, 73, 83, and 93 of the first to sixth semiconductor switches Q1 to Q6 extend from their respective second ends 46B, 56B, 66B, 76B, 86B, and 96B.

[0071] The first semiconductor switch Q1 has (i) a first metal surface 46 and (ii) a first mounting surface 48 opposite the first metal surface 46. The second semiconductor switch Q2 has (i) a second metal surface 56 and (ii) a second mounting surface 58 opposite the second metal surface 56. The third semiconductor switch Q3 has (i) a third metal surface 66 and (ii) a third mounting surface 68 opposite the third metal surface 66. The fourth semiconductor switch Q4 has (i) a fourth metal surface 76 and (ii) a fourth mounting surface 78 (in Fig. 3 and Fig. 4 not shown) opposite the fourth metal surface 76. The fifth semiconductor switch Q5 has (i) a fifth metal surface 86 and (ii) a fifth mounting surface 88 (in Fig. 3 and Fig. 4 not shown) opposite the fifth metal surface 86. The sixth semiconductor switch Q6 has (i) a sixth metal surface 96 and (ii) a sixth mounting surface 98 (in Fig. 3 and Fig. 4 not shown) opposite the sixth metal surface 96.

[0072] The first through sixth metal surfaces 46, 56, 66, 76, 86, and 96 each have metal plates (metallic contact points) that are connected to the respective surfaces of the housings of the first through sixth semiconductor switches Q1 through Q6. The metal plates contain or are made of aluminum, copper, silver, or gold. The first through sixth semiconductor switches Q1 through Q6 are arranged on the first circuit surface 11A such that the first through sixth mounting surfaces 48, 58, 68, 78, 88, and 98 face the first circuit surface 11A. The first through sixth mounting surfaces 48, 58, 68, 78, 88, and 98 are soldered to the first circuit surface 11A.

[0073] The first through sixth semiconductor switches, Q1 to Q6, are arranged on the first circuit surface 11A such that their first ends (46A, 56A, 66A, 76A, 86A, and 96A) are on the front side, and their second ends (46B, 56B, 66B, 76B, 86B, and 96B) are on the back side. Thus, the source terminal (43) of the first semiconductor switch, Q1, is opposite the drain terminal (72) of the fourth semiconductor switch, Q4. The source terminal (53) of the second semiconductor switch, Q2, is opposite the drain terminal (82) of the fifth semiconductor switch, Q5. The source terminal (63) of the third semiconductor switch, Q3, is opposite the drain terminal (92) of the sixth semiconductor switch, Q6. The source terminals 43, 53 and 63 are respectively electrically coupled to the drain terminals 72, 82 and 92 by printed wiring (or conductor tracks or traces) and / or vias (not shown) on the first circuit surface 11A.The printed circuit boards are made of metal foils with relatively high electrical conductivity. More precisely, the metal foils contain copper, silver, or gold. The vias are filled or plated with metal. This metal also contains copper, silver, or gold.

[0074] The first thermistor 27 is located on the first circuit surface 11A between the first semiconductor switch Q1 and the second semiconductor switch Q2. The second thermistor 29 is located on the first circuit surface 11A between the fourth semiconductor switch Q4 and the fifth semiconductor switch Q5. In this example, the first through sixth semiconductor switches Q1 to Q6 each have a first height H1. The first and second thermistors 27 and 29 each have a second height H2. The first height H1 and the second height H2 each correspond to a length in a vertical direction (top-bottom), and the second height H2 is greater than the first height H1.

[0075] The U-phase terminal 45 is located on the first circuit surface 11A between the first semiconductor switch Q1 and the fourth semiconductor switch Q4. The source terminal 43 of the first semiconductor switch Q1, the drain terminal 72 of the fourth semiconductor switch Q4, and the U-phase terminal 45 are electrically coupled. The drain terminal 42 of the first semiconductor switch Q1 is electrically coupled to the power line Lp via printed wiring and / or a via (not shown) on the first circuit surface 11A. The source terminal 73 of the fourth semiconductor switch Q4 is electrically coupled to the ground line Ln via printed wiring and / or a via (not shown) on the first circuit surface 11A.

[0076] The V-phase terminal 55 is located on the first circuit surface 11A between the second semiconductor switch Q2 and the fifth semiconductor switch Q5. The source terminal 53 of the second semiconductor switch Q2, the drain terminal 82 of the fifth semiconductor switch Q5, and the V-phase terminal 55 are electrically coupled. The drain terminal 52 of the second semiconductor switch Q2 is electrically coupled to the power line Lp via printed wiring and / or a via (not shown) on the first circuit surface 11A. The source terminal 83 of the fifth semiconductor switch Q5 is electrically coupled to the ground line Ln via printed wiring and / or a via (not shown) on the first circuit surface 11A.

[0077] The W-phase terminal 65 is located on the first circuit surface 11A between the third semiconductor switch Q3 and the sixth semiconductor switch Q6. The source terminal 63 of the third semiconductor switch Q3, the drain terminal 92 of the sixth semiconductor switch Q6, and the W-phase terminal 65 are electrically coupled. The drain terminal 62 of the third semiconductor switch Q3 is electrically coupled to the power line Lp on the first circuit surface 11A via printed wiring and / or a via (not shown). The source terminal 93 of the sixth semiconductor switch Q6 is electrically coupled to the ground line Ln on the first circuit surface 11A via printed wiring and / or a via (not shown).

[0078] Each elastic component 35 is conductive. In particular, the elastic component 35 is a formed (shaped) spring made of metal, such as copper or aluminum. More precisely, the elastic component 35 has a vertical cross-section that is Z-shaped, but the vertical cross-sectional shape is not limited to a Z-shape. In another embodiment, the elastic component 35 can be a helical spring made of metal. Alternatively, the elastic component 35 can be a foam, the surface of which is coated with a conductive material.

[0079] The respective elastic components 35 are arranged on the first circuit surface 11A to the right of the first semiconductor switch Q1, to the left of the third semiconductor switch Q3, to the right of the fourth semiconductor switch Q4, and to the left of the sixth semiconductor switch Q6. Each elastic component 35 has (i) a first component surface 35A and (ii) a second component surface 35B opposite the first component surface 35A. The first component surface 35A is connected to the first circuit surface 11A by solder (solder metal) or the like.

[0080] Each metal plate 100 is a plate component with a rectangular shape. These metal plates 100 are arranged over the first circuit surface 11A such that their longitudinal directions are along the longitudinal direction (left-right) of the printed circuit board 11. One of the metal plates 100 is arranged to cover the upper surfaces of the three high-side switches (i.e., the first to third semiconductor switches Q1 to Q3). The upper surfaces of the three high-side switches comprise the first to third metal surfaces 46, 56, and 66. The other of the metal plates 100 is arranged to cover the upper surfaces of the three low-side switches (i.e., the fourth to sixth semiconductor switches Q4 to Q6). The upper surfaces of the three low-side switches comprise the fourth to sixth metal surfaces 76, 86, and 96. The metal plates 100 do not cover any of the four elastic components 35.The metal plates 100 are components for improving the dissipation of heat generated in the first to sixth semiconductor switches Q1 to Q6. Although... Fig. Since Figure 4 shows a longitudinal cross-section through the high-side switches, the structure around the low-side switches is similar to that around the high-side switches. Therefore, the structure around the high-side switches is described below, and a description of the structure around the low-side switches is omitted.

[0081] The metal plate 100 has (i) a first plate surface 100A and (ii) a second plate surface 100B opposite the first plate surface 100A. The first plate surface 100A is connected to the first to third metal surfaces 46, 56, and 66 via solder. In another embodiment, the first plate surface 100A can be connected to the first to third metal surfaces 46, 56, and 66 via an adhesive with relatively high thermal conductivity. Examples of such an adhesive include silicone (silicon) and epoxy resin.

[0082] The metal plate 100 comprises a metal base 140, an insulating layer 130, first to third metal foils 111 to 113, a right insulating section 121, first and second insulating sections 122 and 123, and a left insulating section 124. The metal base 140 is a metal plate made of aluminum. That is, the metal base 140 is a metal plate with relatively high thermal conductivity and excellent heat dissipation. In another embodiment, the metal base 140 can be a metal plate made of a different metal, such as copper. The metal base 140 can be any metal plate with excellent heat dissipation. One upper surface of the metal base 140 corresponds to the second plate surface 100B.

[0083] The insulating layer 130 is bonded to a lower surface of the metal base 140. Specifically, an upper surface of the insulating layer 130 is bonded to the lower surface of the metal base 140 by an adhesive or the like. The insulating layer 130 contains, or is made of, a material with excellent electrical insulation and heat dissipation properties. Examples of such materials include silicone and epoxy resin.

[0084] The first to third metal foils 111 to 113, the right insulating section 121, the first and second insulating sections 122 and 123, and the left insulating section 124 are connected to a lower surface of the insulating layer 130. The first to third metal foils 111 to 113, the right insulating section 121, the first and second insulating sections 122 and 123, and the left insulating section 124 form the first plate surface 100A. In other words, the first to third metal foils 111 to 113, the right insulating section 121, the first and second insulating sections 122 and 123, and the left insulating section 124 are contained within the first plate surface 100A.

[0085] The first to third metal foils 111 to 113 are square-shaped metal foils (metal patches) and are, in particular, copper foils. The first to third metal foils 111 to 113 are approximately the same size as the first to third metal surfaces 46, 56, and 66, respectively. In another embodiment, the first to third metal foils 111 to 113 can be other metal foils, such as silver or gold foils.

[0086] The first metal foil 111 is arranged on the first plate surface 100A such that it faces the first metal surface 46. The second metal foil 112 is arranged on the first plate surface 100A such that it faces the second metal surface 56. The third metal foil 113 is arranged on the first plate surface 100A such that it faces the third metal surface 66. That is, the first to third metal foils 111 to 113 are arranged side by side along the longitudinal direction (left-right) of the printed circuit board 11 at the same intervals as those of the first to third semiconductor switches Q1 to Q3.

[0087] The first metal foil 111 is connected to the first metal surface 46 via a solder layer 101. The second metal foil 112 is connected to the second metal surface 56 via a solder layer 102. The third metal foil 113 is connected to the third metal surface 66 via a solder layer 103. However, no electric current flows between the first to third metal foils 111 to 113 and the first to third metal surfaces 46, 56, and 66, respectively. The first to third metal foils 111 to 113 are located on the first plate surface 100A for soldering the metal plate 100 to the first to third semiconductor switches Q1 to Q3. Soldering the first to third metal surfaces 46, 56, and 66 to the metal plate 100 can be difficult depending on the type of metal contained in the metal plate 100. In particular, if the metal contained in the metal plate 100 is aluminum, it is difficult to achieve a solder joint.An integration of the first to third metal foil 111 to 113 in the first plate surface 100A enables the first to third metal surfaces 46, 56 and 66 to be soldered to the first plate surface 100A.

[0088] The solder layers 101 to 103 are each made of an alloy containing lead and / or tin and exhibit higher thermal conductivity than resin or other materials. The first to third semiconductor switches Q1 to Q3 are connected to the metal plate 100 via these solder layers 101 to 103, which have high thermal conductivity. This improves heat dissipation efficiency in the heat dissipation paths from the first to third semiconductor switches Q1 to Q3 to the metal plate 100 compared to a case where the first to third semiconductor switches Q1 to Q3 are connected to the metal plate 100 with resin or another material.

[0089] In another embodiment, the first to third semiconductor switches Q1 to Q3 can be connected to the metal plate 100 via a thermal interface material (TIM), and the first to third metal foils 111 to 113 can be excluded from the metal plate 100. Examples of the TIM include thermal grease (or thermal paste), thermal adhesive, a thermal sheet, a thermal compound, and thermal putty.

[0090] The first and second insulating sections 122 and 123, the right insulating section 121, and the left insulating section 124 are solder resists (or solder masks) applied to the insulating layer 130. In another embodiment, the first and second insulating sections 122 and 123, the right insulating section 121, and the left insulating section 124 may be made of or contain an insulating material. Examples of insulating materials include silicone and epoxy resin.

[0091] The first insulating section 122 is arranged between the first metal foil 111 and the second metal foil 112. The second insulating section 123 is arranged between the second metal foil 112 and the third metal foil 113. The right insulating section 121 is arranged on the right side of the first metal foil 111. The left insulating section 124 is arranged on the left side of the third metal foil 113.

[0092] The metal plate 100 has a through-hole 160 that passes through the first insulating section 122, the insulating layer 130, and the metal base 140 located above the first insulating section 122. The through-hole 160 is aligned with the first thermistor 27, which is mounted on the first circuit surface 11A. Since the second height H2 is greater than the first height H1, the first thermistor 27 does not fit in the space between the first circuit surface 11A and the first insulating section 122. Thus, the through-hole 160 is provided in the metal plate 100. The first thermistor 27 is partially enclosed within the through-hole 160.

[0093] The metal plate 100 has two internal threads 150 formed therein. Each internal thread 150 has a helical thread groove. One of the internal threads 150 is formed on an inner surface of a corresponding through-hole that passes through the right insulating section 121 and through the insulating layer 130 and the metal base 140 located above the right insulating section 121. The other internal thread 150 is formed on an inner surface of a corresponding through-hole that passes through the left insulating section 124 and through the insulating layer 130 and the metal base 140 located above the left insulating section 124. In the present embodiment, the internal threads 150 are each formed on the inner surfaces of the respective through-holes in the metal base 140.In another embodiment, one of the internal threads 150 can be formed on the inner surface of the corresponding through hole in the metal base 140.

[0094] The second plate surface 100B is bonded to an adhesive layer 300. One of the heat dissipation components 200 is in indirect contact with the second plate surface 100B via the adhesive layer 300. The adhesive layer 300 is formed by applying a material with (i) adhesive properties and (ii) a thermal conductivity higher than that of air to the second plate surface 100B or by applying a sheet made of such a material to the second plate surface 100B. In particular, the adhesive layer 300 is formed from the TIM, more precisely from thermal paste. Typically, the second plate surface 100B exhibits fine irregularities. A lower surface of the heat dissipation component 200 also exhibits fine irregularities.The adhesive layer 300 fills a gap between the second plate surface 100B and the lower surface of the heat dissipation component 200, thereby improving heat dissipation efficiency in a heat dissipation path from the metal plate 100 to the heat dissipation component 200. In another embodiment, the adhesive layer 300 and the heat dissipation component 200 can be omitted from the control unit 25. In a case where sufficient heat dissipation can be achieved by the metal plate 100 alone, the heat dissipation component 200 does not need to be connected to the metal plate 100.

[0095] In another embodiment, the adhesive layer 300 can be excluded from the control unit 25 and the heat dissipation component 200 can be directly connected to the second plate surface 100B (see Fig. 11) In yet another embodiment, the metal plate 100 and the adhesive layer 300 can be omitted from the control unit 25. The lower surface of the heat dissipation component 200 can have an insulating layer formed on it, and three metal foils can be provided on the insulating layer. The three metal foils can then be soldered to the first to third metal surfaces 46, 56 and 66 of the first to third semiconductor switches Q1 to Q3.

[0096] The heat dissipation component 200 has a right end and a left end, each of which is in contact with the second component surface 35B of one of the two corresponding elastic components 35. The heat dissipation component 200 is not fixed to the second component surfaces 35B and is supported by the elastic force of the elastic components 35. Thus, assembly tolerances of the first to third semiconductor switches Q1 to Q3, the metal plate 100, the adhesive layer 300, and the heat dissipation component 200 are absorbed by the elastic components 35.

[0097] Since the elastic components 35 are conductive, they electrically couple the circuit board 11 to the heat dissipation component 200. This prevents static electricity from building up on the circuit board 11, thus preventing a local voltage increase on the circuit board 11 caused by static electricity and ultimately preventing damage to the electronic components on the circuit board 11 due to electrostatic discharge.

[0098] In another embodiment, the control unit 25 can have a single heat dissipation component instead of the two heat dissipation components 200, which covers the upper surfaces of the first to sixth semiconductor switches Q1 to Q6. The single heat dissipation component can be supported by a single elastic component or by three or more elastic components. The single elastic component or each of the three elastic components can have a design similar to that of the elastic component 35.

[0099] The heat dissipation component 200 is a heat sink made of metal, such as aluminum or copper. As in Fig. 4 and Fig. As shown in Figure 11, the heat dissipation component 200 has a base 210, several fins 220, and a mounting section 230. The base 210 is plate-shaped and is connected to the adhesive layer 300 such that it is substantially parallel to the printed circuit board 11 and the metal plate 100. The base 210 has two insertion holes 250 extending through it. The insertion holes 250 are each configured to be opposite (or aligned with) a corresponding internal thread 150. The respective inner surfaces of the insertion holes 250 have no threaded grooves and are smooth.

[0100] The lamellae 220 are each plate-shaped. The lamellae 220 are coupled to the base 210 such that their longitudinal directions run along the lateral direction (front-back) of the circuit board 11. The lamellae 220 are arranged parallel to each other in the longitudinal direction (left-right) of the circuit board 11. In another embodiment, the lamellae 220 can be arranged parallel to each other on the base 210 in the lateral direction (front-back) of the circuit board 11 such that their longitudinal directions run along the longitudinal direction (left-right) of the circuit board 11. In yet another embodiment, the lamellae 220 can have a shape other than a plate shape, such as a corrugated or pointed shape.

[0101] The mounting section 230 is plate-shaped and thicker than any of the lamellae 220. The mounting section 230 is connected to a right end part of the base 210 such that its longitudinal direction is along the lateral direction (front-back) of the printed circuit board 11. In another embodiment, the mounting section 230 can be connected to a left end part of the base 210. Alternatively, in another embodiment, the mounting section 230 can be connected to a front end part or a rear end part of the base 210 such that its longitudinal direction is along the longitudinal direction (left-right) of the printed circuit board 11.

[0102] The heat dissipation component 200 has a first contact surface 200a on the underside of the base 210. The first contact surface 200a is in indirect contact with the first to third semiconductor switches Q1 to Q3 via the metal plate 100, etc.

[0103] The heat dissipation component 200 has a second contact surface 200b on the right end face of the mounting section 230, which is different from the first contact surface 200a. The second contact surface 200b extends in a direction that intersects the first contact surface 200a. In the present embodiment, the second contact surface 200b extends perpendicular to the first contact surface 200a.

[0104] Referring again to Fig. 3 and Fig. 4 The second contact surface 200b is in contact with the load switch Q7. The load switch Q7 is a through-hole type. In other words, the load switch Q7 has a through-hole housing (through-hole mounting housing). More precisely, the load switch Q7 is a radial-terminated type (radially wired type). In general, a semiconductor switch with a through-hole housing can have a higher voltage and current rating than a semiconductor switch with a surface-mount housing. In the present embodiment, to ensure high reliability and / or a long service life, the load switch Q7 has a higher voltage and current rating than each of the first through sixth semiconductor switches Q1 through Q6.

[0105] The load switch Q7 has a body 30. The body 30 has a substantially rectangular parallelepiped shape. The load switch Q7 is screwed to the mounting section 230 with an outer surface of the body 30 in contact with the second contact surface 200b of the mounting section 230. In another embodiment, the load switch Q7 can be fixed to the mounting section 230 by clamping it with a clamp or the like, with the outer surface of the body 30 in contact with the second contact surface 200b. Alternatively, in another embodiment, the outer surface of the body 30 can be adhered (glued) to the second contact surface 200b via an interposed component 700, such as a thin adhesive sheet.

[0106] Heat generated in the first to third semiconductor switches Q1 to Q3 is conducted via the metal plate 100 to the heat dissipation component 200 and is then dissipated (emitted / radiated) by the heat dissipation component 200. Heat generated in the load switch Q7 is conducted directly to the heat dissipation component 200 and is then dissipated by the heat dissipation component 200.

[0107] The load switch Q7 has a first terminal 31, a second terminal 32, and a third terminal 33. The first terminal 31 is connected to a gate terminal of the load switch Q7. The second terminal 32 is connected to a drain terminal of the load switch Q7. The third terminal 33 is connected to a source terminal of the load switch Q7. The printed circuit board 11 has vias 131 to 133 formed on it. The vias 131 to 133 extend along their thickness through the printed circuit board 11. The first to third terminals 31 to 33 extend downwards (or protrude) from the body 30. The first to third connections 31 to 33 are (i) inserted into the vias 131 to 131 and (ii) electrically coupled to printed wiring not shown on the first circuit surface 11A through the vias 131 to 133.

[0108] Each externally threaded screw 400 has a threaded section 410. The threaded section 410 is a helical thread groove formed on a cylindrical side face of the externally threaded screw 400. The threaded section 410 is formed at a location on the externally threaded screw 400, which is inserted through the corresponding insertion hole 250, corresponding to the corresponding internal thread 150. The externally threaded screws 400 are each inserted through the corresponding insertion hole 250, and the corresponding threaded section 410 engages with the corresponding internal thread 150. As a result of the threaded sections 410 engaging with the internal threads 150, the heat dissipation component 200 is firmly fixed to the metal plate 100.Furthermore, the degree of adhesion between the heat dissipation component 200 and the adhesive layer 300 and between the adhesive layer 300 and the metal plate 100 increases, thus improving the heat dissipation efficiency from the metal plate 100 to the heat dissipation component 200.

[0109] In another embodiment, instead of the internal threads 150 being formed in the metal plate 100, the control unit 25 can have two nuts (or internally threaded screws) (i.e., the control unit 25 can have a total of four nuts). The two externally threaded screws 400 can each be threaded into a corresponding nut at a corresponding location under the right insulating section 121 or under the left insulating section 124.

[0110] The first to sixth semiconductor switches Q1 to Q6, the two metal plates 100, and the two heat dissipation components 200 are mounted on the circuit board 11, and then the control unit 25 is cast in resin. The resin-cast control unit 25 is housed in the enclosure 2. In another embodiment, after the first to sixth semiconductor switches Q1 to Q6, the two metal plates 100, and the two heat dissipation components 200 have been mounted on the circuit board 11, the control unit 25 can be housed in a casing. The casing is then housed in the enclosure 2. <1-3-2. Modified example>

[0111] A modified example for the control unit 25 is given in relation to Fig. 5 described. The modified example differs from the examples described above in that the first thermistor 27 has a third height H3 instead of a second height H2. Furthermore, the modified example differs from the examples described above in that the metal plate 100 does not have the through-hole 160. The third height H3 is smaller than the first height H1. Therefore, according to the modified example, the first thermistor 27 fits into the space between the first circuit surface 11A and the first insulating section 122; thus, the through-hole 160 is not provided in the metal plate 100 according to the modified example. <1-3-3. Effects>

[0112] The first embodiment, described in detail above, can achieve the following effects: (1) The first semiconductor switch Q1 has a first metal surface 46, and the first metal surface 46 is soldered to the metal plate 100. That is, the heat dissipation path from the first semiconductor switch Q1 to the metal plate 100 is made of metal, which has a higher thermal conductivity than resin or any other material. Thus, the heat generated in the first semiconductor switch Q1 is efficiently conducted via the solder material to the metal plate 100 and dissipated through the metal plate 100. This improves the heat dissipation efficiency of the first semiconductor switch Q1. (2) Since the first plate surface 100A has the first metal foil 111, the first metal foil 111 can be soldered to the first metal surface 46, in other words, the metal plate 100 can be connected to the first semiconductor switch Q1. (3) The metal plate 100 is soldered to the first metal surface 46 of the first semiconductor switch Q1 and to the second metal surface 56 of the second semiconductor switch Q2. This allows the heat generated in the first and second semiconductor switches Q1 and Q2 to be efficiently dissipated through the metal plate 100. (4) Since the first plate surface 100A has the second metal foil 112, the second metal foil 112 can be soldered to the second metal surface 56; in other words, the metal plate 100 can be connected to the second semiconductor switch Q2. Furthermore, since the first insulating section 122 is arranged between the first metal foil 111 and the second metal foil 112, it is prevented that the first semiconductor switch Q1 short-circuits with the second semiconductor switch Q2. (5) Since the first plate surface 100A has the third metal foil 113, the third metal foil 113 can be soldered to the third metal surface 66; in other words, the metal plate 100 can be connected to the third semiconductor switch Q3. Furthermore, since the second insulating section 123 is arranged between the second metal foil 112 and the third metal foil 113, it is prevented that the second semiconductor switch Q2 short-circuits with the third semiconductor switch Q3. (6) Since the first to third semiconductor switches Q1 to Q3 are aligned on the first circuit surface 11A, the first to third semiconductor switches Q1 to Q3 can be connected to the single metal plate 100. This in turn makes it possible to reduce the number of components of the control unit. (7) The control circuit 21 includes the first to sixth semiconductor switches Q1 to Q6. Thus, in a case where a large current has flowed through the control circuit 21, the heat generated in the first to sixth semiconductor switches Q1 to Q6 can be efficiently dissipated through the two metal plates 100. (8) The heat dissipation component 200 is in contact with the second plate surface 100B via the adhesive layer 300. Thus, the heat generated in the first to third semiconductor switches Q1 to Q3 and the heat generated in the fourth to sixth semiconductor switches Q4 to Q6 are conducted via the solder materials 101, 102 and 103 and the metal plate 100 to the heat dissipation component 200 and are then dissipated by the heat dissipation component 200. This makes it possible to further improve the heat dissipation efficiency of the first to third semiconductor switches Q1 to Q3 and the fourth to sixth semiconductor switches Q4 to Q6. [2. Second embodiment]<2-1. Differences from the first embodiment>

[0113] Since a basic design of the second embodiment is similar to that of the first embodiment, differences from the first embodiment are described below. The reference numerals, which are the same as those in the first embodiment, indicate the same components, and reference is made to the preceding descriptions.

[0114] In the control unit 25 of the first embodiment described above, the first to sixth semiconductor switches Q1 to Q6 are mounted on the first circuit surface 11A. In contrast, the control unit 25 according to the second embodiment differs from the control unit 25 according to the first embodiment in that the lower-side switches (i.e., the fourth to sixth semiconductor switches Q4 to Q6) are mounted on the second circuit surface 11B. In other words, in the second embodiment, the electronic components of the control circuit 21 are mounted on the two surfaces of the printed circuit board 11. Thus, the printed circuit board 11 according to the second embodiment is smaller than the printed circuit board 11 according to the first embodiment.

[0115] Furthermore, the control unit 25 of the second embodiment differs from that of the first embodiment (i) in that it has three metal components 600, first to third printed wiring assemblies 511 to 513 and fourth to sixth printed wiring assemblies 521 to 523, and (ii) in that it has one of the heat dissipation components 200 and an additional heat dissipation component 500 instead of the two heat dissipation components 200. <2-2. Control unit>

[0116] An example of the control unit 25 according to the second embodiment is given in relation to Fig. 6, Fig. 7, Fig. 8, Fig. 9 to Fig. 10 described. As in Fig. As shown in Figure 6, the first to third semiconductor switches Q1 to Q3 are arranged in a row along the longitudinal direction (left-right) on the first circuit surface 11A. The first to third semiconductor switches Q1 to Q3 are arranged such that their first ends 46A, 56A and 66A are on the front side, and their second ends 46B, 56B and 66B are on the back side.

[0117] As in Fig. As shown in Figure 7, the fourth to sixth semiconductor switches Q4 to Q6 are arranged in a row along the longitudinal direction (left-right) on the second circuit surface 11B. The fourth to sixth semiconductor switches Q4 to Q6 are positioned across the circuit board 11 relative to the first to third semiconductor switches Q1 to Q6. The fourth to sixth semiconductor switches Q4 to Q6 are arranged such that their second ends 76B, 86B and 96B are on the front side, and their first ends 76A, 86A and 96A are on the rear side.

[0118] Accordingly, the source terminal 43 of the first semiconductor switch Q1 is connected via circuit board 11 to the drain terminal 72 of the fourth semiconductor switch Q4. The source terminal 53 of the second semiconductor switch Q2 is connected via circuit board 11 to the drain terminal 82 of the fifth semiconductor switch Q5. The source terminal 63 of the third semiconductor switch Q3 is connected via circuit board 11 to the drain terminal 92 of the sixth semiconductor switch Q6.

[0119] The printed circuit board 11 has first to third through-holes 501 to 503 extending through the board. These first to third through-holes 501 to 503 are slots extending longitudinally (left-right). They are located in the immediate vicinity of the respective source terminals 43, 53, and 63 and the respective gate terminals 41, 51, and 61 (e.g., within 10 mm of the terminals) along the respective second ends 46B, 56B, and 66B of the first to third semiconductor switches Q1 to Q3. Accordingly, the first to third plate through-holes 501 to 503 are arranged in the immediate vicinity of the drain terminals 72, 82 and 92 along the respective first ends 46A, 86A and 96A of the fourth to sixth semiconductor switches Q4 to Q6.

[0120] The length of each of the first to third plate through-holes 501 to 503 in the longitudinal direction (left-right) is essentially equal to the width of at least one corresponding of the first to sixth semiconductor switches Q1 to Q6 in the longitudinal direction (left-right). In another embodiment, the respective planar shapes of the first to third plate through-holes 501 to 503 can be elliptical, circular, or polygonal.

[0121] The metal components 600 are each inserted into a corresponding hole in the first to third plate through-hole 501 to 503. Fig. 6 and Fig. For simplicity, the first and second plate through-holes 501 and 502 show the respective metal components 600 inserted therein, and the other metal component 600 is removed from the third plate through-hole 503. In practice, all of the first to third plate through-holes 501 to 503 are filled with the respective metal components 600.

[0122] The metal components 600 contain or are formed from a metal with relatively high electrical conductivity. Examples of such metals include copper, silver, gold, and aluminum. The metal components 600 are solid components that are prefabricated. In another embodiment, at least one of the three metal components 600 can be formed from conductive paste, which is filled into one of the first to third through-holes 501 to 503 of the plate and then hardened or sintered. The conductive paste can be a metal paste, more specifically a gold paste, silver paste, copper paste, or aluminum paste. In yet another embodiment, at least one of the three metal components 600 can be formed from solder material, which is filled into one of the first to third through-holes 501 to 503 of the plate and then solidified.

[0123] As in Fig. As shown in Figure 8, the metal components 600 each have a first part 610 and a second part 620. The first part 610 has a substantially rectangular parallelepiped shape. In a horizontal planar view, the size of the first part 610 in its longitudinal direction is larger than that of each of the first to third through-holes 501 to 503 in the longitudinal (left-right) direction of the printed circuit board 11. In a horizontal planar view, the size of the first part 610 in its lateral direction is slightly smaller than that of each of the first to third through-holes 501 to 503 in the lateral (front-back) direction of the printed circuit board 11, but may be the same size or larger. The second part 620 has a shape similar to a rectangular parallelepiped.The second part 620 is connected to a lower surface of the first part 610 such that the longitudinal direction of the second part 620 is aligned with the longitudinal direction of the first part 610. The size of the second part 620 in its longitudinal direction is slightly smaller than that of each of the first to third through-holes 501 to 503 in the longitudinal direction (left-right) of the printed circuit board 11. The size of the second part 620 in its lateral direction is slightly smaller than that of each of the first to third through-holes 501 to 503 in the lateral direction (front-back) of the printed circuit board 11. The height of the second part 620 is essentially equal to the thickness of the printed circuit board 11. The metal components 600 each have a T-shaped vertical cross-section, but may have a vertical cross-section of a different shape.

[0124] The metal components 600 are each inserted into a corresponding through-hole 501 to 503 of the first to third circuit board surface 11A in the direction of the second circuit board surface 11B. The first components 610 are engaged with the first circuit board surface 11A, thus preventing the corresponding metal component 600 from detaching from the circuit board 11. The second components 620 are each received in a corresponding through-hole 501 to 503 of the first to third circuit board surface 11B.

[0125] As in Fig. 6 and Fig. As shown in Figure 9, each of the first to third printed wires 511 to 513 is arranged between a corresponding source terminal 43, 53 and 63 of the first to third semiconductor switches Q1 to Q3 and a corresponding through-hole of the first to third disk 501 to 503. Furthermore, each of the first to third printed wires 511 to 513 is arranged on the rear side of a corresponding through-hole of the first to third disk 501 to 503.

[0126] The first to third printed wires 511 to 513 are electrically coupled to the source terminals 43, 53, and 63, respectively. Specifically, the first to third printed wires 511 to 513 are soldered to the source terminals 43, 53, and 63, respectively. Furthermore, the first to third printed wires 511 to 513 are each electrically coupled to a corresponding metal component 600. Specifically, the first to third printed wires 511 to 513 are each soldered to the first part 610 of the corresponding metal component 600. The metal components 600 are each electrically coupled to a corresponding U-phase terminal 45, a V-phase terminal 55, and a W-phase terminal 56 via a corresponding connection of the first to third printed wires 511 to 513.

[0127] In the areas between source terminal 43 and the corresponding metal component 600, between source terminal 53 and the corresponding metal component 600, and between source terminal 63 and the corresponding metal component 600, solder mask 15 is applied to the first to third printed wires 511 to 513. Additionally, in areas on the rear faces of the three metal components 600, solder mask 15 is applied to the first to third printed wires 511 to 513. The solder mask 15 is not applied under the first to third mounting surfaces 48, 58, and 68. The respective lower ends of the gate terminals 41, 51, and 61, the drain terminals 42, 52, and 62, and the source terminals 43, 53, and 63 are slightly raised above a corresponding area on the first to third mounting surfaces 48, 58, and 68.If the solder mask 15 were applied under the first to third mounting surfaces 48, 58 and 68, soldering the gate terminals 41, 51 and 61, the drain terminals 42, 52 and 62 and the source terminals 43, 53 and 63 would be difficult.

[0128] As in Fig. 7 and Fig. As shown in Figure 9, each of the fourth to sixth printed wires 521 to 523 is arranged between a corresponding drain terminal 72, 82, 92 of the fourth to sixth semiconductor switches Q4 to Q6 and a corresponding first to third through-hole 501 to 503. Furthermore, each of the fourth to sixth printed wires 521 to 523 is arranged on the rear side of a corresponding first to third through-hole 501 to 503.

[0129] The fourth to sixth printed wires 521 to 523 are electrically connected to the drain terminals 72, 82, and 92, respectively. Specifically, the fourth to sixth printed wires 521 to 523 are soldered to the drain terminals 72, 82, and 92, respectively. Furthermore, the fourth to sixth printed wires 521, 522, and 523 are each electrically connected to a corresponding metal component 600. Specifically, the fourth to sixth printed wires 521 to 522 are each soldered to the second part 620 of the corresponding metal component 600. The metal components 600 are each electrically connected to a corresponding U-phase terminal 45, a V-phase terminal 55, and a W-phase terminal 56 via a corresponding printed wire 521 to 523.

[0130] In areas between drain terminal 72 and the corresponding metal component 600, between drain terminal 82 and the corresponding metal component 600, and between drain terminal 92 and the corresponding metal component 600, the solder mask 15 is applied to the fourth to sixth printed wires 521 to 523. Additionally, in areas on the rear faces of the three metal components 600, the solder mask 15 is applied to the fourth to sixth printed wires 521 to 523. The solder mask 15 is not applied under the fourth to sixth mounting surfaces 78, 88, and 98.

[0131] Each of the source terminals 43, 53, 63 of the first to third semiconductor switches Q1 to Q3 is electrically coupled to a corresponding drain terminal 72, 82, 92 of the fourth to sixth semiconductor switches Q4 to Q6 via a corresponding metal component 600. This minimizes the lengths of the printed wires from the source terminals 43, 53, and 63 to the respective drain terminals 72, 82, and 92. This results in a reduction of the inductive component of the control circuit 21. Consequently, the surge voltages associated with the switching operations of the first to sixth semiconductor switches Q1 to Q6 are suppressed, thus allowing for lower nominal voltages in these switches. This also reduces the heat generated in the first to sixth semiconductor switches Q1 to Q6.Consequently, at least one of the metal plates 100, the heat dissipation components 200 and 500 can be omitted or made smaller, and the electronic components on the circuit board 11 can be reduced in size. This, in turn, allows for a reduction in the size and cost of the control unit 25.

[0132] It is also possible to couple the source terminals 43, 53, and 63 electrically to the drain terminals 72, 82, and 92 via the printed circuit boards and vias, respectively, without using the metal components 600. However, in the case of coupling these terminals via the printed circuit boards and vias, the printed circuit boards must be longer, and the inductive component of the printed circuit boards can be increased. This, in turn, increases the surge voltages associated with the switching operations of the first through sixth semiconductor switches Q1 to Q6.

[0133] As in Fig. As shown in Figure 10, similar to the first embodiment, one of the metal plates 100 and the heat dissipation component 200 are connected to the upper-side switches. Conversely, the other metal plate 100 and the heat dissipation component 500 are connected to the lower-side switches. The heat dissipation component 500 is fundamentally the same as the heat dissipation component 200. The differences between the heat dissipation component 500 and the heat dissipation component 200 are described below.

[0134] The heat dissipation component 500 has a base 510, several fins 520, and an outer circumferential wall 540. The base 510 is a plate-shaped component that is longer than the base 210 in the longitudinal direction (left-right) of the printed circuit board 11. The fins 520 have the same shape as the fins 220. The heat dissipation component 500 does not have a section corresponding to the mounting section 230. The fins 520 are connected to the base 510 such that their longitudinal directions run along the lateral direction (front-back) of the printed circuit board 11. The fins 520 are arranged parallel to each other in the longitudinal direction (left-right) of the printed circuit board 11.In another embodiment, the lamellae 520 can be arranged parallel to each other in the lateral direction (front-back) of the circuit board 11 on the base 510 such that their longitudinal directions are along the longitudinal direction (left-right) of the circuit board 11. In yet another embodiment, the lamellae 520 can have a shape other than a plate shape, such as a corrugated shape or a pointed shape.

[0135] The outer perimeter wall 540 is connected to an upper surface of the base 510. The outer perimeter wall 540 has a height that is essentially the same as the length from the upper surface of the base 510 to an upper end of the heat dissipation component 200. The outer perimeter wall 540 surrounds the circuit board 11, the two metal plates 100, and the heat dissipation component 200 on its left, right, front, and rear sides.

[0136] The first to sixth semiconductor switches Q1 to Q6, the two metal plates 100, and the heat dissipation components 200 and 500 are mounted on the circuit board 11, and then resin is injected into the interior of the outer circumferential wall 540, thus casting the control unit 25 with the resin. The resin-cast control unit 25 is housed in the enclosure 2.

[0137] In another embodiment, the outer perimeter wall 540 can be omitted from the heat dissipation component 500. In this case, the control unit 25 is held in a mold and cast (molded) with resin. The resin-cast control unit 25 is then housed in the casing 2. Alternatively, in the case where the outer perimeter wall 540 is omitted, the control unit 25 can be housed in a sleeve. The control unit 25 housed in the sleeve is then housed in the casing 2. <2-3. Modified Example>

[0138] In Fig. 10. The first and second thermistors 27 and 29 each have the second height H2, and the metal plates 100 each have the plate through-hole 160. However, this can be modified as in the modified example of the first embodiment, which is shown in Fig. Figure 5 can be modified. In particular, an embodiment can be used in which the first and second thermistors 27 and 29 each have the third height H3 and in which the metal plates 100 each do not have the plate through-hole 160. <2-4. Effects>

[0139] The second embodiment, which has been described in detail above, can achieve the effects (1) to (8) of the first embodiment described above. [3. Other embodiments] (a) In each of the embodiments described above, the single metal plate 100 is connected to the three high-sided switches, and the other single metal plate 100 is connected to the three low-sided switches. However, the present disclosure is not limited thereto. As in Fig. 3, Fig. 6 and Fig.As shown in Figure 7 with dotted lines, a single metal plate 100 can be connected to a single semiconductor switch. In such a case, where separate metal plates 100 are connected to the corresponding semiconductor switches, the degree of freedom in the arrangement of the semiconductor switches increases. In other words, the three high-side switches and / or the three low-side switches do not necessarily have to be arranged in a row. That is, the six semiconductor switches can be arranged arbitrarily on the first circuit surface 11A, or on the first circuit surface 11A and the second circuit surface 11B. Alternatively, a single metal plate 100 can be connected to two of the semiconductor switches. Furthermore, a single heat dissipation component 200 or another single heat dissipation component can be attached to a single metal plate 100 using the externally threaded screws 400.Alternatively, a single heat dissipation component 200 or another single heat dissipation component can be attached to two or more metal plates 100 using the external threaded screws 400. (b) In each of the embodiments described above, the first and second thermistors 27 and 29, which have the second height H2, are mounted on the circuit board 11. However, other circuit components having the second height H2 can be mounted in place of the first and second thermistors 27 and 29. Furthermore, although in each modified example of the embodiments described above the first and second thermistors 27 and 29, which have the third height H3, are mounted on the circuit board 11, other circuit components having the third height H3 can be mounted in place of the first and second thermistors 27 and 29.

[0140] It is explicitly emphasized that all features disclosed in the description and / or the claims are to be considered separate and independent of one another for the purposes of the original disclosure as well as for the purpose of limiting the claimed invention, irrespective of the combinations of features in the embodiments and / or the claims. It is explicitly stated that all range specifications or specifications of groups of units disclose every possible intermediate value or subgroup of units for the purposes of the original disclosure as well as for the purpose of limiting the claimed invention, in particular also as a boundary of a range specification. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] JP 5512110

[0002]

Claims

[1] Electric working machine (1) with: a motor (20) designed to receive electrical power from a power supply (12) so that it is driven by it; a printed circuit board (11); a first semiconductor switch (Q1) on the circuit board (11), which has a first metal surface (46) and a first mounting surface (48) and is electrically coupled to the power supply (12) and to the motor (20), which first mounting surface (48) is opposite the first metal surface (46) and is opposite the circuit board (11); and a first metal plate (100) with: a first plate surface (100A) soldered to the first metal surface (46); and a second plate surface (100B) opposite the first plate surface (100A). [2] Electric working machine (1) according to claim 1, wherein: the first plate surface (100A) has a first metal foil (111); and the first metal foil (111) is soldered to the first metal surface (46). [3] Electric working machine (1) according to claim 1 or 2, further comprising a second semiconductor switch (Q2) on the circuit board (11), which is different from the first semiconductor switch (Q1), has a second metal surface (56) and a second mounting surface (58) and is electrically coupled to the power supply (12) and to the motor (20), which second mounting surface (58) is opposite the second metal surface (56) and is opposite the circuit board (11), where the first plate surface (100A) is soldered to the first metal surface (46) and to the second metal surface (56). [4] Electric machine according to claim 2, further comprising a second semiconductor switch (Q2) on the circuit board (11), which is different from the first semiconductor switch (Q1), has a second metal surface (56) and a second mounting surface (58) and is electrically coupled to the power supply (12) and to the motor (20), which second mounting surface (58) is opposite the second metal surface (56) and is opposite the circuit board (11), wherein: the first plate surface (100A) has: a second metal foil (112); and a first insulating section (122) located between the first metal foil (111) and the second metal foil (112) and on the first plate surface (100A); and the second metal foil (112) is soldered to the second metal surface (56). [5] Electric machine (1) according to claim 4, further comprising a third semiconductor switch (Q3) on the circuit board (11), which is different from the first semiconductor switch (Q1) and the second semiconductor switch (Q2), has a third metal surface (66) and a third mounting surface (68) and is electrically coupled to the power supply (12) and to the motor (20), which third mounting surface (68) is opposite the third metal surface (66) and is opposite the circuit board (11), wherein: the first plate surface (100A) has: a third metal foil (113); and a second insulating section (123) located between the second metal foil (112) and the third metal foil (113) and on the first plate surface (100A); and the third metal foil (113) is soldered to the third metal surface (66). [6] Electric working machine (1) according to claim 5, wherein: the first semiconductor switch (Q1), the second semiconductor switch (Q2) and the third semiconductor switch (Q3) are arranged in a row on the circuit board (11), and the first metal plate (100) covers the first metal surface (46), the second metal surface (56) and the third metal surface (66). [7] Electric working machine (1) according to claim 5 or 6, wherein the first semiconductor switch (Q1), the second semiconductor switch (Q2) and the third semiconductor switch (Q3) form at least part of a control circuit (21) for controlling the motor (20). [8] Electric working machine (1) according to claim 1 or 2, further comprising: a second semiconductor switch (Q2) on the circuit board (11), which is different from the first semiconductor switch (Q1), has a second metal surface (56) and a second mounting surface (58) and is electrically coupled to the power supply (12) and to the motor (20), which second mounting surface (58) is opposite the second metal surface (56) and is opposite the circuit board (11); and a second metal plate (100) which is different from the first metal plate (100) and is soldered to the second metal surface (56). [9] Electric working machine (1) according to one of claims 1 to 8, further comprising a heat dissipation component (200) in direct or indirect contact with the second plate surface (100B). [10] Electric working machine (1) according to any one of claims 6 to 9, wherein: the circuit board (11) and the first metal plate (100) each have a rectangular shape; the first semiconductor switch (Q1), the second semiconductor switch (Q2) and the third semiconductor switch (Q3) are arranged along a longitudinal direction of the printed circuit board (11); and a longitudinal direction of the first metal plate (100) is aligned with the longitudinal direction of the circuit board (11). [11] Electric working machine (1) according to claim 9 or 10, wherein the heat dissipation component (200; 500) has two or more fins (220; 520). [12] Electric working machine (1) according to any one of claims 1 to 11, wherein the first metal plate (100) comprises: a metal base (140) with the second plate surface (100B); and an insulating layer (130) which is connected to the metal base (140) and to the first metal foil (111). [13] Method for assembling a control unit (25) for controlling a motor (20) of an electric working machine (1), comprising: Mounting a semiconductor switch (Q1) of the control unit (25) on a printed circuit board (11) of the control unit (25), the semiconductor switch (Q1) having a mounting surface (48) and a metal surface (46) opposite the mounting surface (48), which mounting surface (48) is opposite the printed circuit board (11); and Soldering a metal plate (100) to the metal surface (46).

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