Electric work machine

Abstract

To make it possible to reduce heat generation in a power supply circuit, which supplies power source power to a circuit that controls drive of a motor, in an electric work machine.SOLUTION: An electric work machine comprises a first electric conduction route, a motor, a motor drive circuit, a first power supply circuit, and a power source control circuit. AC power is inputted to the first electric conduction route from an AC power source. The motor is provided on the first electric conduction route. The motor drive circuit is operated by first electric power. The first power supply circuit generates the first electric power from the AC power in response to reception of a power supply control signal. The first power supply circuit stops generation of the first electric power in response to stop of input of the power supply control signal. The power source control circuit outputs the power supply control signal in response to establishment of drive conditions.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to an electric work machine. [Background technology]

[0002] Patent Document 1 discloses a power tool equipped with a motor that is driven by AC power from an AC power source. This power tool includes a motor control IC that controls the driving of the motor, and a power supply unit that supplies power to the motor control IC. The power supply unit receives the AC power and generates power from the AC power. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-012149 Summary of the Invention [Problem to be solved by the invention]

[0004] In the above-mentioned power tool, the power supply unit supplies power to the motor control IC both when the motor is driven and when it is not. Therefore, there is a possibility that malfunctions may occur due to heat generated by the power supply unit. Alternatively, it may become necessary to take measures to suppress heat generation by the power supply unit.

[0005] An object of one aspect of the present disclosure is to reduce heat generation in a power supply circuit that supplies power to a circuit that controls the drive of a motor in an electric work machine. [Means for solving the problem]

[0006] According to one aspect of the present disclosure, an electric operating machine includes a first current path through which AC power is input from an AC power source. The electric work machine includes a motor. The motor is provided on a first current path and is driven by AC power. The electric work machine includes a drive mechanism. A tool is removably attached to the drive mechanism. The drive mechanism transmits rotation of the motor to the tool.

[0007] The electric work machine includes a motor drive circuit that is activated by receiving a first power and controls the supply of AC power to the motor. The electric operating machine includes a first power supply circuit. The first power supply circuit receives AC power from a first current path. The first power supply circuit further receives a power supply control signal. In response to receiving the power supply control signal, the first power supply circuit generates first power from the AC power. In response to input of the power supply control signal being stopped, the first power supply circuit stops generating the first power.

[0008] The electric work machine includes a power supply control circuit. The power supply control circuit is activated by receiving second power. The power supply control circuit outputs a power supply control signal to the first power supply circuit when a drive condition is met. The power supply control circuit stops outputting the power supply control signal when the drive condition is not met.

[0009] The electric operating machine includes a second power supply circuit that generates second electric power from AC power and supplies the second electric power to the power supply control circuit. In such an electric operating machine, it is possible to reduce heat generation in the first power supply circuit.

[0010] In the power tool disclosed in the aforementioned Patent Document 1, the power supply consumes AC power supplied from an AC power source to generate power, regardless of whether the motor is driven. This power supply generates heat due to heat loss associated with the generation of power. Therefore, it is desirable to be able to efficiently dissipate the heat generated by the power supply from the power supply.

[0011] More specifically, the power supply unit described in Patent Document 1 includes a capacitor, a resistor, and a diode connected in series. When AC power is supplied to this power supply unit, the capacitor is charged. Charging the capacitor generates power supply power with a constant DC voltage. The AC voltage of the AC power supply is rectified by the diode to become a DC voltage. The resistor is provided to step down this DC voltage and apply it to the capacitor. The resistor generates heat due to the DC current flowing through it when power supply power is generated. Because a relatively large current flows through the resistor, the amount of heat generated by the resistor can be large. Therefore, it is particularly desirable to be able to efficiently dissipate the heat generated by this resistor.

[0012] Therefore, in another aspect of the present disclosure, it is desirable to be able to efficiently dissipate heat generated from the power supply circuit in the electric operating machine. More specifically, in another aspect of the present disclosure, it is desirable to be able to efficiently dissipate heat generated from electronic components (e.g., resistors) in the power supply circuit that cause heat loss.

[0013] That is, another aspect of the present disclosure includes the following items. [Item 1] a power input unit configured to receive AC power; a motor configured to be driven by the AC power input to the power input unit; a circuit board including a substrate and an electronic circuit mounted on the substrate, the electronic circuit having a function of controlling the AC power supplied to the motor, and the electronic circuit having electronic components that may generate heat loss; A heat dissipation member configured to conduct heat generated from the circuit board and dissipate the conducted heat, (i) a plate-shaped first heat sink disposed parallel to the substrate and spaced a first distance from the substrate; and (ii) a plate-shaped second heat sink arranged parallel to the substrate and spaced a second distance from the substrate, the second heat sink being thermally coupled to the first heat sink, the second distance being shorter than the first distance; a heat dissipation member having An electric work machine equipped with:

[0014] In such an electric operating machine, heat generated from the circuit board is conducted to the first and second heat sinks directly and / or via a space, and can be dissipated from the first and second heat sinks. The second distance between the second heat sink and the board is shorter than the first distance between the first heat sink and the board. By providing the first and second heat sinks, which are at different distances from the board, it is possible to efficiently dissipate heat generated from the circuit board to the outside of the circuit board.

[0015] To improve heat dissipation performance, it is possible to use a large heat sink equipped with multiple large heat dissipation fins. However, using such a heat sink would result in an increase in the size of the electric power tool. In contrast, in the electric power tool of this item 1, the heat dissipation member has two heat dissipation plates at different distances from the circuit board, which allows for efficient dissipation of heat from the circuit board while preventing the heat dissipation member from becoming too large.

[0016] The term "thermal coupling" as used herein means that the two parts are in direct physical contact with each other, or that the two parts are in direct contact (connected) with tangible members, allowing heat to be transferred between them via those tangible members. Even when the two parts are not in contact with each other but are separated by a space, heat can still be transferred between them by so-called convection or thermal radiation, but such a state does not fall under the category of thermal coupling as used herein.

[0017] [Item 2] The electric operating machine according to item 1 above, The second heat sink is provided so that the electronic components are located in an area of ​​the surface of the substrate that faces the second heat sink.

[0018] In other words, the electronic components are disposed between the second heat sink and the circuit board. In such an electric operating machine, heat generated by the electronic components can be efficiently dissipated via the second heat sink. [Item 3] The electric operating machine according to item 1 or 2 above, The second heat sink is arranged so that the second heat sink faces at least partially the first heat sink in a direction perpendicular to the substrate.

[0019] In such an electric operating machine, the heat dissipation member has a two-layer structure in which a first heat dissipation plate and a second heat dissipation plate are at least partially laminated, which makes it possible to prevent the heat dissipation member from becoming too large. [Item 4] The electric operating machine according to item 3 above, the heat dissipation member further includes a connecting portion (or a bending portion) that thermally couples the first heat dissipation plate and the second heat dissipation plate, the first heat dissipation plate, the second heat dissipation plate, and the connecting portion are integrally formed as the same component; Electric work equipment.

[0020] That is, the heat dissipation member is formed so that the cross section perpendicular to the substrate is approximately U-shaped. In other words, the heat dissipation member has a shape formed by bending a plate material approximately 180 degrees, and the bent part corresponds to the above-mentioned connecting part.

[0021] In such an electric operating machine, it is possible to easily form a heat dissipation member having a two-layer structure. [Item 5] The electric operating machine according to item 1 or 2 above, The heat dissipation member further includes a plate-shaped third heat dissipation plate thermally coupled to the second heat dissipation plate.

[0022] In this electric operating machine, as in the electric operating machines described in items 3 and 4 above, heat generated from electronic components can be efficiently dissipated via the second heat sink. Furthermore, according to item 5, heat transferred from the circuit board to the second heat sink can be dissipated from the first and third heat sinks. This further improves heat dissipation efficiency.

[0023] The second heat sink may be disposed between the third heat sink and the substrate in a direction perpendicular to the substrate. More specifically, the second heat sink may be disposed as described in the next item 6. [Item 6] The electric operating machine according to item 5 above, The third heat sink is arranged parallel to the substrate and spaced a third distance from the substrate, the third distance being longer than the second distance, and is arranged so as to at least partially face the second heat sink in a direction perpendicular to the substrate.

[0024] In such an electric operating machine, the heat dissipation member has a two-layer structure in which the second heat dissipation plate and the third heat dissipation plate are at least partially laminated, which prevents the heat dissipation member including the first to third heat dissipation plates from becoming too large.

[0025] [Item 7] The electric operating machine according to item 6 above, the heat dissipation member further includes a connecting portion that thermally couples the second heat dissipation plate and the third heat dissipation plate, the first heat dissipation plate, the second heat dissipation plate, the third heat dissipation plate, and the connecting portion are integrally formed as the same component. Electric work equipment.

[0026] That is, the heat dissipation member is formed so that the second heat dissipation plate, the connecting portion, and the third heat dissipation plate have a cross section that is approximately U-shaped. In other words, the heat dissipation member has a shape formed by bending a plate material approximately 180 degrees, and the bent portion corresponds to the connecting portion.

[0027] In such an electric operating machine, it is possible to easily form a heat dissipation member with a two-layer structure in which the second and third heat dissipation plates are stacked. Furthermore, the second heat dissipation plate is thermally coupled to both the first and third heat dissipation plates. In other words, in a configuration including the first, second, and third heat dissipation plates, the second heat dissipation plate is positioned midway among these three. This makes it possible to maintain a high degree of accuracy in the distance between the second heat dissipation plate and the circuit board.

[0028] [Item 8] The electric operating machine according to item 6 or 7 above, The electric work machine, wherein the third distance is equal to the first distance.

[0029] [Item 9] The electric operating machine according to item 8 above, The electric operating machine, wherein the first heat dissipation plate and the third heat dissipation plate are arranged spaced apart on approximately the same plane.

[0030] In the electric operating machine described in items 8 and 9, the shape of the heat dissipation member can be prevented from becoming complicated, and the heat dissipation member can be easily formed. The circuit board may be housed in a case. The case may be filled with a filler material. In this case, the heat dissipation member may be partially immersed (or embedded) in the filler material. Specifically, for example, the second heat dissipation plate may be completely immersed in the filler material, and the first and third heat dissipation plates may not be immersed at all or may be partially immersed in the filler material. When the first and third heat dissipation plates are configured as described in item 8 or item 9, it is easy to fill the filler material so that the first and third heat dissipation plates are not completely immersed in the filler material.

[0031] [Item 10] The electric operating machine according to any one of items 1 to 9 above, the electronic component includes a resistor; The heat dissipation member is disposed so as to be spaced apart from the resistor without contacting the resistor. Electric work equipment.

[0032] In such an electric operating machine, heat generated from the resistor can be efficiently released via the heat dissipation member while maintaining insulation between the resistor and the heat dissipation member. [Item 11] The electric operating machine according to any one of items 1 to 10 above, The electronic circuit a current path electrically connecting the power input unit and the motor, the current path being configured to supply the AC power input to the power input unit to the motor; a switching element provided in the current path, the switching element being configured to conduct or interrupt the current path and being thermally coupled to the heat dissipation member; An electric work machine equipped with:

[0033] In such an electric operating machine, the heat generated from the switching element can be efficiently dissipated via the heat dissipation member. [Item 12] The electric operating machine according to item 11 above, The switching element is thermally coupled to the first heat sink.

[0034] In such an electric operating machine, the switching element can be efficiently cooled via the first heat sink, and components that are lower in height from the circuit board can be efficiently cooled via the second heat sink. For example, if the electronic components are smaller than the switching element and lower in height from the circuit board, it is possible to efficiently cool both of them while preventing the heat sink from becoming too large.

[0035] At least one of the components may be omitted from each of the electric operating machines described above in items 1 to 12. For example, in the electric operating machine described in item 1, at least one of the power input unit, the motor, the circuit board, and the heat sink unit may be omitted. [Brief explanation of the drawings]

[0036] [Figure 1] 1 is a perspective view of an electric working machine according to an embodiment. [Figure 2] FIG. 2 is an explanatory diagram showing the configuration of an electrical system of the electric operating machine. [Figure 3] FIG. 4 is an explanatory diagram illustrating an example of a power supply control signal. [Figure 4] 10 is a flowchart of a power supply control process. [Figure 5] FIG. 2 is a perspective view of a controller according to an embodiment. [Figure 6] FIG. 1 is a perspective view of a controller without the case. [Figure 7] FIG. 1 is a front view of the controller with the case removed. [Figure 8] FIG. 2 is a perspective view of the heat dissipation member as viewed from the front right. [Figure 9] FIG. 2 is a perspective view of the heat dissipation member as seen from the left rear. [Figure 10] FIG. 10 is a perspective view of a modified example of the controller. DETAILED DESCRIPTION OF THE INVENTION

[0037] [1. Overview of the embodiment] In an embodiment, the electric work machine may include a first current path. The first current path may be configured to receive AC power from an AC power supply. Additionally / alternatively, the electric work machine may include a motor. The motor may be provided on the first current path. The motor may be configured to be driven by AC power. Additionally / alternatively, the electric work machine may include a drive mechanism. The drive mechanism may be configured to allow a tool to be removably attached thereto. The drive mechanism may be configured to transmit rotation of the motor to the tool.

[0038] Additionally / alternatively, the electric work machine may include a motor drive circuit. The motor drive circuit may be activated by receiving the first power. The motor drive circuit may be configured to control the supply of AC power to the motor.

[0039] Additionally / alternatively, the electric work machine may include a first power supply circuit. The first power supply circuit may be configured to receive AC power from the first current path. The first power supply circuit may further be configured to receive a power supply control signal. The first power supply circuit may be configured to generate the first power from the AC power in response to receiving the power supply control signal. The first power supply circuit may be configured to stop generating the first power in response to input of the power supply control signal being stopped.

[0040] Additionally / alternatively, the electric operating machine may include a power supply control circuit. The power supply control circuit may be configured to be activated by receiving the second power. The power supply control circuit may be configured to output a power supply control signal to the first power supply circuit in response to the drive condition being satisfied. The power supply control circuit may be configured to stop outputting the power supply control signal in response to the drive condition not being satisfied.

[0041] Additionally / alternatively, the electric work machine may include a second power supply circuit. The second power supply circuit may generate second electric power from AC power. The second power supply circuit may be configured to supply the generated second electric power to the power supply control circuit.

[0042] In one embodiment, when an electric work machine is equipped with the first current path, the motor, the drive mechanism, the motor drive circuit, the first power supply circuit, the power supply control circuit, and the second power supply circuit, such an electric work machine can reduce heat generation in the first power supply circuit.

[0043] Additionally / alternatively, the first power supply circuit may be configured to stop consuming AC power in the first power supply circuit in response to the input of the power supply control signal being stopped.When an electric operating machine in one embodiment includes a first power supply circuit having the above-mentioned features, such an electric operating machine can further reduce heat generation in the first power supply circuit.

[0044] Additionally / alternatively, the first power supply circuit may include a second current path. The second current path may be connected to the first current path. The second current path may be configured to receive AC power from the first current path.

[0045] Additionally / alternatively, the first power supply circuit may include a power supply drive switch. The power supply drive switch may be provided on the second current path. The power supply drive switch may be configured to receive a power supply control signal. The power supply drive switch may be configured to turn on the second current path in response to receiving the power supply control signal. The power supply drive switch may be configured to cut off the second current path in response to stopping the input of the power supply control signal.

[0046] When an electric operating machine in one embodiment is equipped with a first power supply circuit having the above-described characteristics, such an electric operating machine can achieve a reduction in heat generation in the first power supply circuit with a simple configuration.

[0047] Additionally / alternatively, the power supply driven switch may be configured to interrupt the second current path in response to the voltage of the AC power becoming zero or close to zero (e.g., the voltage value being less than a lower limit value) while the second current path is conducting.

[0048] More specifically, the power supply drive switch may be, for example, a bidirectional thyristor. Even if the power supply control signal causes the second current path to change from a cutoff state to a conduction state and then the power supply control signal is discontinued, such a power supply drive switch maintains the conduction state as long as a current equal to or greater than a predetermined level flows through the power supply drive switch. When the current flowing through the power supply drive switch becomes zero or close to zero (for example, the current value is less than a certain value), the power supply drive switch cuts off the second current path.

[0049] When an electric operating machine in one embodiment includes a power supply drive switch having the above-described features, such an electric operating machine can easily cut off the supply of AC power to the first power supply circuit.

[0050] Additionally / alternatively, the power supply control signal may include a pulse. When an electric working machine in an embodiment includes a power supply control circuit configured to output the above-described power supply control signal, the electric working machine can easily control the operation of the first power supply circuit, i.e., the power consumption by the first power supply circuit.

[0051] Additionally / alternatively, the electric operating machine may include a zero-crossing detection circuit. The zero-crossing detection circuit may be configured to detect zero-crossings of a voltage or a current of the AC power. The zero-crossings may include at least a zero-crossing at a rising edge of the voltage or the current of the AC power. Additionally / alternatively, the power supply control signal may include a period signal. The period signal may be output for a first time each time at least a zero-crossing at a rising edge is detected by the zero-crossing detection circuit.

[0052] In one embodiment, when an electric work machine is equipped with the above-mentioned zero-cross detection circuit and a power supply control circuit configured to output the above-mentioned power supply control signal, such an electric work machine can make the power supply drive switch, which has been cut off when the current flowing through the power supply drive switch becomes zero or less than a lower limit value, conductive again at least every time a zero cross occurs during startup.

[0053] Additionally / alternatively, the periodic signal may include a plurality of pulses at a fixed cycle. In an embodiment, when an electric operating machine includes a power supply control circuit configured to output a power supply control signal including the periodic signal, such an electric operating machine can appropriately turn on the power supply drive switch while reducing the power consumption required to output the power supply control signal.

[0054] Additionally / alternatively, the power supply control circuit may be configured to output the period signal after a second time has elapsed since the zero-cross detection circuit detected the zero-cross. At the time of zero-cross detection or shortly thereafter, the AC voltage applied to the power supply drive switch is low, and there is a possibility that the power supply drive switch will not be turned on even if a power supply control signal is input to the power supply drive switch. Therefore, by outputting the period signal after the second time has elapsed since the zero-cross detection, it is possible to reduce the power consumption required for the power supply control circuit to output the power supply control signal.

[0055] Additionally / alternatively, the electric work machine may include a manual switch. The manual switch may be provided on the first current path. The manual switch may be configured to turn on or off the first current path in response to manual operation by a user of the electric work machine. Additionally / alternatively, the zero-crossing detection circuit may be configured to receive AC power from between the manual switch and the motor in the first current path. In an embodiment, when an electric work machine includes the above-described manual switch and the zero-crossing detection circuit having the above-described features, the zero-crossing detection circuit does not detect zero crossings while the first current path is interrupted by the manual switch. In other words, no power supply control signal is output while the first current path is interrupted by the manual switch. Therefore, such an electric work machine can suppress AC power consumption by the first power supply circuit while the first current path is interrupted by the manual switch (i.e., while AC power to the motor is interrupted).

[0056] Additionally / alternatively, the first power supply circuit may be connected to a first location in the first current path between the manual switch and the motor. The first power supply circuit may be configured to receive AC power via the first location. In an embodiment, when an electric operating machine includes the manual switch and the first power supply circuit having the above-described features, AC power is not supplied to the first power supply circuit while the first current path is interrupted by the manual switch. Therefore, such an electric operating machine can more efficiently prevent AC power from being consumed by the first power supply circuit while the first current path is interrupted by the manual switch (i.e., while AC power to the motor is interrupted).

[0057] Additionally / alternatively, the second power supply circuit may be connected to a second portion of the first current path closer to the AC power supply than the manual switch. The second power supply circuit may receive AC power from the second portion and generate second power from the AC power. In one embodiment, when an electric operating machine includes a second power supply circuit having the above-described characteristics, the power supply control circuit can operate regardless of the state of the manual switch. Therefore, the power supply control circuit can properly control the first power supply circuit regardless of the state of the manual switch.

[0058] Additionally / alternatively, the drive condition may be satisfied in response to the first current path being turned on by a manual switch after activation of the power supply control circuit. In an embodiment, when an electric operating machine includes a power supply control circuit that operates in response to a drive signal such as that described above, the electric operating machine can operate the first power supply circuit to supply first power to the motor drive circuit in response to a user's intention to drive the motor.

[0059] Additionally / alternatively, the motor drive circuit may include a motor drive switch. The motor drive switch may be provided on the first current path. The motor drive switch may be configured to receive a motor drive signal. The motor drive switch may be configured to turn on or off the first current path in accordance with the motor drive signal.

[0060] Additionally / alternatively, the motor drive circuit may include a motor control circuit configured to receive a first power source and configured to be activated by receiving the first power source to generate the motor drive signal.

[0061] When an electric working machine in one embodiment is equipped with a motor drive circuit having the above-described features, such an electric working machine can easily and efficiently control the power supply to the motor with a simple configuration.

[0062] The motor drive switch may be, for example, a bidirectional thyristor. A motor drive circuit including such a motor drive switch can efficiently control the supply of AC power to the motor.

[0063] Additionally / alternatively, the electric working machine may include a signal output circuit. The signal output circuit may be configured to output a speed signal corresponding to the rotational speed of the motor. Additionally / alternatively, the motor control circuit may be configured to execute a first process. The first process may include obtaining a target speed indicating a target rotational speed. Additionally / alternatively, the motor control circuit may be configured to execute a second process. The second process may include generating a motor drive signal based on the rotational speed indicated by the speed signal output from the signal output circuit and the target speed obtained by the first process so that the rotational speed matches the target speed.

[0064] When an electric working machine in one embodiment is equipped with the above-described signal output circuit and a motor control circuit having the above-described features, such an electric working machine can appropriately control the rotation speed of the motor.

[0065] Additionally / alternatively, the electric operating machine may include a circuit board. The circuit board includes a substrate and a first power supply circuit. The first power supply circuit is mounted on the substrate. The first power supply circuit includes electronic components that may generate heat loss. Additionally / alternatively, the electric operating machine may include a heat dissipation member. Heat generated from the circuit board is conducted to the heat dissipation member. The heat dissipation member dissipates the heat conducted from the circuit board. The heat dissipation member may include a first heat dissipation plate and / or a second heat dissipation plate. The first heat dissipation plate is a plate-shaped member arranged parallel to the substrate and spaced a first distance from the substrate. The second heat dissipation plate is a plate-shaped member arranged parallel to the substrate and spaced a second distance from the substrate. The second heat dissipation plate is thermally coupled to the first heat dissipation plate. The second distance is shorter than the first distance. In one embodiment, when an electric operating machine is equipped with the above-mentioned circuit board and heat dissipation member, such an electric operating machine can efficiently dissipate heat generated from the circuit board to the outside of the circuit board (or efficiently cool the circuit board).

[0066] Additionally / alternatively, the electronic components may include resistors. When an electric operating machine in an embodiment includes the resistor, the electric operating machine can efficiently dissipate heat generated by the resistor (or efficiently cool the resistor).

[0067] Additionally / alternatively, the second heat sink may be provided so that the electronic components are located in an area of ​​the surface of the substrate facing the second heat sink. When an electric operating machine in one embodiment includes the second heat sink, the electric operating machine can efficiently dissipate heat generated by the electronic components via the second heat sink.

[0068] Additionally / alternatively, the second heat sink may be provided so that the second heat sink at least partially faces the first heat sink in a direction perpendicular to the substrate. That is, the heat sink has a two-layer structure in which the first heat sink and the second heat sink are at least partially laminated. When an electric operating machine in one embodiment includes the heat sink described above, the electric operating machine can prevent the heat sink from becoming large.

[0069] Additionally / alternatively, the heat dissipation member may include a connecting portion. The connecting portion thermally couples the first heat dissipation plate and the second heat dissipation plate. Additionally / alternatively, the first heat dissipation plate, the second heat dissipation plate, and the connecting portion may be integrally formed as a single component. When an electric operating machine in one embodiment includes the heat dissipation member described above, it becomes possible to easily form a heat dissipation member with a two-layer structure in such an electric operating machine.

[0070] Additionally / alternatively, the heat dissipation member may include a third heat dissipation plate. The third heat dissipation plate is thermally coupled to the second heat dissipation plate. When an electric operating machine in one embodiment includes the heat dissipation member described above, the electric operating machine can efficiently dissipate heat generated by electronic components via the second heat dissipation plate. Specifically, heat transferred from the circuit board to the second heat dissipation plate can be efficiently dissipated from the first heat dissipation plate and the third heat dissipation plate.

[0071] Additionally / alternatively, the third heat sink may be disposed parallel to the substrate and spaced a third distance from the substrate. The third distance is longer than the second distance. The third heat sink may be disposed so as to at least partially face the second heat sink in a direction perpendicular to the substrate. In other words, this heat sink has a two-layer structure in which the second heat sink and the third heat sink are at least partially stacked. When an electric operating machine in one embodiment includes the heat sink described above, the electric operating machine can prevent the heat sink from becoming large.

[0072] Additionally / alternatively, the heat dissipation member may include a connecting portion. The connecting portion thermally couples the second heat dissipation plate and the third heat dissipation plate. Additionally / alternatively, the first heat dissipation plate, the second heat dissipation plate, the third heat dissipation plate, and the connecting portion may be integrally formed as the same component. Additionally / alternatively, the third distance may be equal to the first distance. Additionally / alternatively, the first heat dissipation plate and the third heat dissipation plate may be arranged spaced apart on approximately the same plane. When an electric operating machine in one embodiment includes the above-described heat dissipation plate portion, it becomes easy to form a heat dissipation member with a two-layer structure in which the second and third heat dissipation plates are stacked.

[0073] Additionally / alternatively, the heat dissipation member may be disposed so as to be spaced apart from the electronic components without contacting them. When an electric operating machine in one embodiment includes the heat dissipation member described above, the electric operating machine can efficiently dissipate heat generated from the electronic components via the heat dissipation member while maintaining insulation between the electronic components and the heat dissipation member.

[0074] Additionally / alternatively, the circuit board may include a first current path and a motor drive circuit. Additionally / alternatively, the motor drive circuit may include a motor drive switch provided on the first current path and configured to turn on or off the first current path. Additionally / alternatively, the motor drive switch may be thermally coupled to the first heat sink. When an electric operating machine in one embodiment includes the above-described circuit board and heat sink, the electric operating machine can efficiently dissipate heat generated from the motor drive switch via the heat sink.

[0075] 2. SPECIFIC ILLUSTRATIVE EMBODIMENTS (2-1) Overview of electric work equipment As shown in Fig. 1, the electric operating machine 1 of this embodiment is, for example, a grinder. Grinders are capable of grinding, cutting, etc., workpieces such as metal, concrete, and wood. The electric operating machine 1 of this embodiment receives AC power from an AC power source 100 (see Fig. 2) such as a commercial power source, and is driven by the AC power.

[0076] The electric working machine 1 includes a motor housing 2. The motor housing 2 has a cylindrical shape. A motor 15 (see FIG. 2) is housed inside the motor housing 2. The motor 15 is disposed in the motor housing 2 so that, for example, the rotation axis of the motor 15 (ie, the rotation axis of the rotor) is parallel to and substantially coincides with the central axis of the motor housing 2.

[0077] The electric working machine 1 further includes a rear housing 3. The rear housing 3 is provided at a first end (for example, the rear end) of the motor housing 2. The rear housing 3 is held by a user of the electric working machine 1.

[0078] The electric working machine 1 further includes a power cord 12. The power cord 12 extends from a first end (e.g., the rear end) of the rear housing 3. That is, the first end of the power cord 12 is connected to the rear housing 3. A power plug 14 (see FIG. 2) is provided at a second end of the power cord 12. When the power plug 14 is connected to the AC power source 100, AC power from the AC power source 100 is supplied to the electric working machine 1 via the power cord 12.

[0079] The electric working machine 1 further includes a gear housing 4. The gear housing 4 is provided at a second end (for example, the front end) of the motor housing 2. The rotation shaft of the motor 15 protrudes toward the gear housing 4.

[0080] The gear housing 4 includes a spindle 5. The spindle 5 is rotatably supported by the gear housing 4 via a bearing (not shown) inside the gear housing 4. In this embodiment, the spindle 5 is provided so as to protrude in a direction perpendicular to the rotation axis of the motor 15, for example. That is, in this embodiment, the rotation axis of the spindle 5 is perpendicular to the rotation axis of the motor 15.

[0081] An inner flange 6 is provided on the spindle 5. A tool (not shown) for grinding, cutting, etc. the workpiece is removably attached to the inner flange 6. The tool may be, for example, a disc-shaped grindstone or a cutter. A lock nut 7 is threaded onto the tip of the spindle 5. The lock nut 7 secures the tool to the inner flange 6 and prevents the tool from falling off the inner flange 6. The tool is clamped between the lock nut 7 and the inner flange 6.

[0082] A transmission mechanism (not shown) is provided inside the gear housing 4. The transmission mechanism transmits the rotation of the motor 15 to the spindle 5. The spindle 5 rotates when the rotation of the motor 15 is transmitted to the spindle 5 via the transmission mechanism. Therefore, when the rotation of the motor 15 is transmitted to the spindle 5 to which a tool is attached, the tool rotates together with the spindle 5. In other words, the spindle 5 transmits the rotation of the motor 15 to the tool.

[0083] The electric work machine 1 further includes a wheel cover 8. The wheel cover 8 protects the user from flying fragments of the workpiece and the tool that are generated when working with the tool. The wheel cover 8 of this embodiment has, for example, a substantially semicircular shape. The wheel cover 8 of this embodiment is attached to the gear housing 4 so as to cover, for example, a portion (for example, approximately half) of the tool fixed to the spindle 5 from the gear housing 4 side.

[0084] The electric working machine 1 further includes a handle 10. In this embodiment, the handle 10 is detachably attached to, for example, the gear housing 4. More specifically, in this embodiment, the handle 10 protrudes, for example, from the side surface of the gear housing 4 in a direction perpendicular to both the rotation axis of the motor 15 and the rotation axis of the spindle 5.

[0085] The handle 10 is held by a user. The user can use the electric working machine 1, for example, by holding the rear housing 3 with one hand (for example, the right hand) and the handle 10 with the other hand (for example, the left hand). The user can adjust the position of the tool relative to the workpiece via the handle 10.

[0086] The electric work machine 1 further includes a main switch 11. In this embodiment, the main switch 11 is provided, for example, on the rear housing 3. The main switch 11 is manually operated by the user. Specifically, the main switch 11 is turned on or off by manual operation by the user. The main switch 11 in this embodiment is configured to perform, for example, momentary operation. That is, the main switch 11 is turned on when manually operated (for example, pulled) by the user, and is turned off when not manually operated by the user. The motor 15 is stopped when the main switch 11 is turned off, and rotates in response to the main switch 11 being turned on. However, in this embodiment, there are cases in which the motor 15 does not rotate even when the main switch 11 is turned on.

[0087] The main switch 11 may be provided in a location other than the rear housing 3. The main switch 11 may be provided in, for example, the motor housing 2. The main switch 11 may be a switch that operates differently from a momentary operation. Specifically, the main switch 11 may be a switch that operates in an alternate manner. The main switch 11 may be a switch that operates differently from the trigger type described above. Specifically, the main switch 11 may be, for example, a push button switch or a slide switch.

[0088] (2-2) Electrical configuration of electric work machine As shown in Fig. 2, the electric work machine 1 receives AC power from an AC power supply 100. Specifically, the electric work machine 1 of this embodiment is equipped with the aforementioned power plug 14. The power plug 14 has a first input terminal 14a and a second input terminal 14b. When the power plug 14 is connected to the AC power supply 100, AC power is input from the AC power supply 100 to the inside of the electric work machine 1 via the first input terminal 14a and the second input terminal 14b.

[0089] The electric working machine 1 includes a first current path 21 and the aforementioned motor 15. The motor 15 is provided on the first current path 21. In this embodiment, the motor 15 is, for example, an AC motor with brushes. AC power input to the electric working machine 1 from the power plug 14 is supplied to the motor 15 through the first current path 21. The motor 15 is driven by this AC power. Note that the motor 15 may be any type of motor configured to rotate upon receiving AC power.

[0090] A first end of the first current path 21 is connected to a first input terminal 14a of the power plug 14. A second end of the first current path 21 is connected to a second input terminal 14b of the power plug 14. AC power is input to the first current path 21 from the AC power supply 100 via the power plug 14.

[0091] The motor 15 is provided on a first current path 21 extending from the first input terminal 14a to the second input terminal 14b. The motor 15 has a first terminal 15a and a second terminal 15b. The motor 15 receives AC power via the first terminal 15a and the second terminal 15b.

[0092] More specifically, the first current path 21 includes a first path 21a and a second path 21b. A first end of the first path 21a corresponds to a first end of the first current path 21. That is, the first end of the first path 21a is connected to the first input terminal 14a. A second end of the first path 21a is connected to the first terminal 15a of the motor 15.

[0093] A first end of the second path 21b corresponds to a second end of the first current path 21. That is, the first end of the second path 21b is connected to the second input terminal 14b. The second end of the second path 21b is connected to the second terminal 15b of the motor 15.

[0094] 2, the main switch 11 is electrically provided on the first current path 21. More specifically, in this embodiment, the main switch 11 is provided on the second path 21b. That is, a first end of the main switch 11 is connected to the second input terminal 14b, and a second end of the main switch 11 is connected to the second terminal 15b of the motor 15. The main switch 11 may also be provided on the first path 21a.

[0095] The main switch 11 conducts or cuts off the first current path 21 in response to manual operation of the main switch 11 by a user. Specifically, when the main switch 11 is turned on by manual operation by the user, the main switch 11 conducts the first current path 21. When the manual operation by the user is released and the main switch 11 is turned off, the main switch 11 cuts off the first current path 21.

[0096] The electric work machine 1 further includes a motor drive circuit 30. The motor drive circuit 30 has a function of supplying AC power to the motor 15. The motor drive circuit 30 further has a function of controlling the AC power supplied to the motor 15.

[0097] The motor drive circuit 30 is activated by receiving the first power and operates using the first power. In other words, the first power is the power supply power of the motor drive circuit 30 (more specifically, the power supply power of the motor control circuit 31, which will be described later). The first power is supplied from a first power supply circuit 32, which will be described later.

[0098] The motor drive circuit 30 includes a motor drive switch 25 and the aforementioned motor control circuit 31. The motor drive switch 25 is provided on the first current path 21. More specifically, in this embodiment, the motor drive switch 25 is provided on the first path 21a. The motor drive switch 25 may also be provided on the second path 21b.

[0099] The motor drive switch 25 receives a motor drive signal from the motor control circuit 31. The motor drive switch 25 turns on or off the first current path 21 in accordance with the motor drive signal.

[0100] In this embodiment, the motor drive switch 25 is a triac (i.e., a bidirectional thyristor). In this embodiment, a first end of the triac is connected to the first input terminal 14a. A second end of the triac is connected to the first terminal 15a of the motor 15. A second terminal 15b of the motor 15 is connected to the second input terminal 14b via another part of the first current path 21. A motor drive signal is input to the gate (i.e., control terminal) of the triac.

[0101] When a motor drive signal is input to the triac with a predetermined bias applied between the first and second terminals of the triac, the triac turns on (i.e., conducts or ignites), and first current path 21 becomes conductive. As a result, AC power from AC power supply 100 is supplied to motor 15 via the triac.

[0102] When the value of the current flowing through the turned-on triac falls below a first lower limit value that is the minimum value required to maintain the turned-on state, the triac is turned off (i.e., cut off or extinguished), and the first current path 21 is cut off. This cuts off the supply of AC power from the AC power supply 100 to the motor 15.

[0103] The motor control circuit 31 is activated by receiving a first power and operates using the first power. The motor control circuit 31 controls the supply of AC power to the motor 15. Specifically, the motor control circuit 31 generates the motor drive signal described above. The motor control circuit 31 may include, for example, a logic circuit including multiple electronic components, an IC, or the like, an application specific integrated circuit such as an ASIC and / or ASSP, a programmable logic device such as an FPGA that can configure any logic circuit, or a microcomputer.

[0104] The electric work machine 1 further includes a zero-cross detection circuit 41. The zero-cross detection circuit 41 detects zero crossings of the voltage or current of AC power input from the AC power supply 100. In this embodiment, the zero-cross detection circuit 41 detects zero crossings of the AC voltage. Specifically, the zero-cross detection circuit 41 in this embodiment is connected to the first connection point 23 in the first current path 21. The first connection point 23 is located in the second path 21b, between the main switch 11 and the second terminal 15b of the motor 15. The zero-cross detection circuit 41 detects zero crossings of the voltage at the first connection point 23.

[0105] The zero-crossing detection circuit 41 outputs a zero-crossing detection signal ZC. In this embodiment, the zero-crossing detection signal ZC is a binary signal. That is, the signal level of the zero-crossing detection signal ZC changes each time a zero crossing occurs. As illustrated in FIG. 3, the zero-crossing detection signal ZC changes to an H level when a zero crossing (a falling zero crossing) occurs when the AC voltage Va changes from a positive half cycle to a negative half cycle. The zero-crossing detection signal ZC changes to an L level when a zero crossing (a rising zero crossing) occurs when the AC voltage Va changes from a negative half cycle to a positive half cycle. The AC voltage Va refers to the voltage of the first path 21a, more specifically, the voltage of the first input terminal 14a.

[0106] Although the voltage input to the zero-crossing detection circuit 41 is the voltage of the second path 21b, the timing at which zero crossings occur on the first path 21a and the second path 21b are the same. In other words, the positive half-cycle of the AC voltage Va corresponds to the negative half-cycle of the AC voltage on the second path 21b, and the negative half-cycle of the AC voltage Va corresponds to the positive half-cycle of the AC voltage on the second path 21b. Therefore, for ease of explanation, FIG. 3 illustrates the relationship between the zero-crossing timings of the AC voltage Va and the zero-crossing detection signal ZC.

[0107] The zero-cross detection signal ZC is input to the motor control circuit 31 and a power supply control circuit 40, which will be described later. The zero-cross detection circuit 41 may detect zero-crossings of AC current in AC power. The zero-cross detection circuit 41 may detect both rising zero-crossings and falling zero-crossings in the AC voltage or AC current to be detected, or may detect only one of them.

[0108] The electric operating machine 1 further includes a first power supply circuit 32. The first power supply circuit 32 generates the above-mentioned first electric power. The first electric power operates the motor drive circuit 30 (more specifically, the motor control circuit 31). The first power supply circuit 32 is connected to the first current path 21 and receives AC power from the first current path 21.

[0109] The first power supply circuit 32 further receives a power supply control signal SD from the power supply control circuit 40. In response to receiving the power supply control signal SD, the first power supply circuit 32 generates a first power from AC power. The first power supply circuit 32 stops generating the first power in response to input of the power supply control signal SD being stopped. More specifically, the first power supply circuit 32 of this embodiment stops consumption of AC power in the first power supply circuit 32 in response to input of the power supply control signal SD being stopped. The first power is DC power. The first power has a DC first voltage Vc1. Although the first voltage Vc1 may pulsate in the strict sense, it can be treated as a DC voltage.

[0110] As will be described later, the first power supply circuit 32 of this embodiment includes a triac coupler. Due to the function (or electrical properties) of this triac coupler, in this embodiment, the first power supply circuit 32 does not immediately stop generating the first power even when the input of the power supply control signal SD is stopped. In this embodiment, the first power supply circuit 32 that is generating the first power stops generating the first power in accordance with the phase of the input AC current.

[0111] The first power supply circuit 32 includes a second current path 22. The second current path 22 is connected to the first current path 21. AC power is input to the first power supply circuit 32 from the first current path 21 via the second current path 22.

[0112] Specifically, a first end of the second current path 22 is connected to the first path 21a. A second end of the second current path 22 is connected to the second path 21b. More specifically, the second end of the second current path 22 is connected to the second path 21b, between the main switch 11 and the second terminal 15b of the motor 15. Therefore, AC power is input to the first power supply circuit 32 while the main switch 11 is turned on. No AC power is input to the first power supply circuit 32 while the main switch 11 is turned off.

[0113] The first power supply circuit 32 further includes a first Zener diode ZD1, a power drive switch 35, and a first diode D1. The first Zener diode ZD1, the power drive switch 35, and the first diode D1 are provided on the second current path 22.

[0114] The cathode of the first Zener diode ZD1 is connected to the first path 21a and receives AC voltage from the AC power supply 100. The anode of the first Zener diode ZD1 is connected to a first terminal of the power supply drive switch 35. The second terminal of the power supply drive switch 35 is connected to the anode of the first diode D1. In this embodiment, a resistor R1 is connected between the power supply drive switch 35 and the first diode D1. The second terminal of the power supply drive switch 35 is connected to the anode of the first diode D1 via the resistor R1. The cathode of the first diode D1 is connected to the second path 21b.

[0115] The first power supply circuit 32 further includes a first capacitor C1. A first end of the first capacitor C1 is connected to the cathode of the first Zener diode ZD1. A second end of the first capacitor C1 is connected to the anode of the first Zener diode ZD1. A first power is generated mainly by the first Zener diode ZD1 and the first capacitor C1.

[0116] The power drive switch 35 of this embodiment indirectly receives the power control signal SD. That is, the first power circuit 32 includes a first drive circuit 36. In this embodiment, the power control signal SD is directly input to the first drive circuit 36. In response to receiving the power control signal SD, the first drive circuit 36 ​​outputs a power drive signal corresponding to the power control signal SD. This power drive signal is input to the power drive switch 35.

[0117] The power supply drive switch 35 turns on in response to receiving a power supply drive signal from the first drive circuit 36 ​​(i.e., indirectly receiving the power supply control signal SD), and conducts the second current path 22. The power supply drive switch 35 cuts off the second current path 22 in response to the input of the power supply drive signal being stopped.

[0118] However, in this embodiment, the power drive switch 35 is a so-called triac coupler. Therefore, in this embodiment, the power control signal SD is generated taking into account the characteristics of the triac coupler. Also, due to the characteristics of the triac coupler, the triac coupler does not immediately turn off even when the input of the power control signal SD is stopped. The timing at which the triac coupler turns off (i.e., the timing at which the second current path 22 is interrupted) depends on the phase of the AC current flowing through the triac coupler.

[0119] The power switch 35 of this embodiment will be specifically described. The power switch 35 includes a phototriac 35a and an LED 35b. The phototriac 35a basically has the function of controlling bidirectional current, similar to a typical triac. However, the phototriac 35a is turned on (i.e., conductive or ignited) by light from the LED 35b. That is, the phototriac 35a has a light-receiving surface (e.g., a PN junction) that receives light from the LED 35b. This light-receiving surface and the LED 35b function as a photocoupler.

[0120] The phototriac 35a is provided in the second current path 22 and turns on or off the second current path 22. The first terminal of the power supply switch 35 described above corresponds to the first terminal of the phototriac 35a. The second terminal of the power supply switch 35 described above corresponds to the second terminal of the phototriac 35a.

[0121] When a bias of a certain level or higher is applied between the first and second terminals of the phototriac 35a and the light-receiving surface of the phototriac 35a receives light from the LED 35b, the phototriac 35a turns on (i.e., conducts or ignites), and the second current path 22 becomes conductive. This causes an AC current to be input from the AC power supply 100 to the first power supply circuit 32 through the second current path 22. Then, a first power is generated by the first Zener diode ZD1 and the first capacitor C1.

[0122] While the first power is being generated, i.e., while the phototriac 35a is on, if the value of the current flowing through the phototriac 35a falls below a second lower limit value that is the minimum value required to maintain the on state, the phototriac 35a turns off (i.e., cuts off or extinguishes), cutting off the second current path 22. As a result, no AC current is input to the first power supply circuit 32 from the AC power supply 100, and power consumption by the first power supply circuit 32 becomes zero or almost zero.

[0123] The power drive signal input from the first drive circuit 36 ​​to the power drive switch 35 has the same phase as the power control signal SD and has a current sufficient to light the LED 35b. The first drive circuit 36 ​​includes an NPN-type first transistor Tr1. The base of the first transistor Tr1 is connected to a resistor R5. A power control signal SD from the power supply control circuit 40 is input to the base of the first transistor Tr1 via the resistor R5. The base of the first transistor Tr1 is connected to the emitter of the first transistor Tr1 via a resistor R6. The emitter of the first transistor Tr1 is connected to the first ground line. The collector of the first transistor Tr1 is connected to a first terminal of a resistor R7. The second terminal of the resistor R7 is connected to the cathode of the LED 35b. The second terminal of the resistor R7 is further connected to a first terminal of a resistor R8. A second voltage Vc2 generated by a second power supply circuit 42 (described later) is input to the second terminal of the resistor R8. The second terminal of the resistor R8 is further connected to the anode of the LED 35b. A third diode D3 is connected in parallel to the resistor R8. The anode of the third diode D3 is connected to the first end of the resistor R8, and the cathode of the third diode D3 is connected to the second end of the resistor R8.

[0124] In the first drive circuit 36 ​​configured in this manner, the first transistor Tr1 is off while the power supply control signal SD is not input. As a result, no current is supplied from the first drive circuit 36 ​​to the LED 35b, and the power drive switch 35 is off. On the other hand, when the power supply control signal SD is input, the first transistor Tr1 is turned on. As a result, current flows from the first drive circuit 36 ​​to the LED 35b, causing the LED 35b to emit light. When the LED 35b emits light while a bias of a certain level or higher is applied to the phototriac 35a, the phototriac 35a is turned on (i.e., the power drive switch 35 is turned on).

[0125] As illustrated in FIG. 3, the power supply control signal SD of this embodiment includes a period signal SDo. The period signal SDo is output every half cycle of the AC voltage Va. Specifically, the period signal SDo is output every time a zero cross is detected by the zero-cross detection circuit 41. In more detail, in this embodiment, the power supply control circuit 40 outputs the period signal SDo after a waiting time Ta has elapsed since the zero-cross timing. The zero-cross timing is the timing at which the zero-cross is detected by the zero-cross detection circuit 41. The power supply control circuit 40 of this embodiment outputs the period signal SDo in response to the detection of a rising zero cross, and outputs the period signal SDo in response to the detection of a falling zero cross.

[0126] The waiting time Ta is determined in advance, taking into consideration the time required from the time when the zero crossing is detected until a bias of a certain level or more is applied to the phototriac 35a. For example, the waiting time Ta may be determined within a range of a time equal to or greater than the required time and shorter than a half cycle of the AC voltage.

[0127] 3, the period signal SDo includes multiple pulses at a fixed cycle. The pulse width of each pulse is Tp. The output cycle of the multiple pulses is Tb. Each pulse can illuminate the LED 35b of the power drive switch 35. In other words, even if only one pulse is input to the first drive circuit 36, a power drive signal corresponding to that pulse is supplied from the first drive circuit 36 ​​to the LED 35b, causing the LED 35b to illuminate.

[0128] Therefore, the period signal SDo does not necessarily have to have multiple pulses. The period signal SDo may have at least one pulse. However, in this embodiment, the period signal SDo includes multiple pulses to ensure that the power drive switch 35 is turned on at the correct timing.

[0129] The first power supply circuit 32 further includes a PNP-type second transistor Tr2. The emitter of the second transistor Tr2 is connected to the cathode of the first Zener diode ZD1. The collector of the second transistor Tr2 is connected to the anode of the first Zener diode ZD1. A drive signal is input from the second drive circuit 44 to the base of the second transistor Tr2.

[0130] The second drive circuit 44 outputs a drive signal in response to receiving a short-circuit command from the power supply control circuit 40. When the drive signal is input to the base of the second transistor Tr2, the second transistor Tr2 turns on. When the second transistor Tr2 turns on, the anode and cathode of the first Zener diode ZD1 are short-circuited by the second transistor Tr2, and the generation of the first power (i.e., the generation of the first voltage Vc1) is stopped. When the generation of the first power is stopped, the operation of the motor control circuit 31 stops and the motor drive switch 25 is maintained off. This stops the motor 15. In other words, the power supply control circuit 40 can forcibly stop the motor 15 by outputting a short-circuit command.

[0131] The electric work machine 1 further includes a switch detection circuit 33. The switch detection circuit 33 detects the state of the main switch 11. The switch detection circuit 33 outputs a switch detection signal TR that indicates the detected state of the main switch 11. The switch detection signal TR is input to the power supply control circuit 40 and the motor control circuit 31.

[0132] The electric operating machine 1 further includes the aforementioned power supply control circuit 40. The power supply control circuit 40 is activated upon receiving the second power and operates using the second power. The power supply control circuit 40 outputs a power supply control signal SD to the first power supply circuit 32 when the drive condition is met. The power supply control circuit 40 stops outputting the power supply control signal SD when the drive condition is not met. The power supply control circuit 40 of this embodiment includes, for example, a CPU and a memory. The memory may include, for example, semiconductor memory such as ROM, RAM, NVRAM, or flash memory. That is, the power supply control circuit 40 of this embodiment includes a microcomputer. The power supply control circuit 40 realizes various functions by executing programs stored in a non-transitory tangible recording medium. In this embodiment, the memory corresponds to the non-transitory tangible recording medium storing the programs. In this embodiment, the memory stores a program for the power supply control process (see FIG. 4), which will be described later. Some or all of the various functions realized by the power supply control circuit 40 may be achieved by executing a program (i.e., by software processing) or by one or more pieces of hardware. For example, instead of or in addition to a microcomputer, the power supply control circuit 40 may include a logic circuit including multiple electronic components, an application specific integrated circuit such as an ASIC and / or ASSP, or a programmable logic device such as an FPGA that can configure any logic circuit.

[0133] The power supply control circuit 40 receives a zero-cross detection signal ZC from a zero-cross detection circuit 41. The power supply control circuit 40 also receives a switch detection signal TR from a switch detection circuit 33. The power supply control circuit 40 can detect zero crosses of the AC voltage based on the zero-cross detection signal ZC. The power supply control circuit 40 can detect whether the main switch 11 is turned on based on the switch detection signal TR.

[0134] The driving condition includes, for example, that the main switch 11 is turned on. That is, while the main switch 11 is turned on, the power supply control circuit 40 outputs a power supply control signal SD as shown in Fig. 3 based on the zero-crossing detection signal ZC. Note that the power supply control signal SD shown in Fig. 3 is just an example, and the power supply driving switch 35 may be turned on by a power supply control signal different from the power supply control signal SD shown in Fig. 3.

[0135] Here, a first half cycle and a second half cycle are defined for one cycle of the AC current input from the AC power supply 100. The first half cycle is a period during which the voltage at the first input terminal 14a is higher than that at the second input terminal 14b. The second half cycle is a period during which the voltage at the second input terminal 14b is higher than that at the first input terminal 14a.

[0136] In the first half cycle, when the power drive switch 35 is turned on, an AC current is input to the first power supply circuit 32. On the other hand, the first power supply circuit 32 of this embodiment includes a first diode D1. Therefore, in the second half cycle, even if the power drive switch 35 is turned on, no AC current is input to the first power supply circuit 32. That is, in this embodiment, an AC current can be input to the first power supply circuit 32 only in the first half cycle of the AC current. In other words, the diode D1 rectifies (e.g., half-wave rectifies) the AC current input to the first power supply circuit 32 to convert it into a DC voltage. The DC voltage is stepped down by the resistor R1. The voltage stepped down by the resistor R1 is applied to the first capacitor C1.

[0137] Therefore, when a zero crossing is detected and the zero crossing corresponds to the start of the second half cycle, the power supply control circuit 40 does not need to output the period signal SDo. In other words, the power supply control circuit 40 may output the period signal SDo and turn on the power drive switch 35 only when a zero crossing corresponding to the start of the first half cycle is detected. In this case, the power consumption of the power supply control circuit 40 for generating and outputting the power supply control signal SD is reduced.

[0138] The electric operating machine 1 further includes a second power supply circuit 42. The second power supply circuit 42 receives AC power from the AC power supply 100 and generates second power from the AC power. The second power supply circuit 42 supplies the generated second power to the power supply control circuit 40. The second power is DC power. The second power has a DC second voltage Vc2. Although the second voltage Vc2 may pulsate in the strict sense, it can be treated as a DC voltage.

[0139] In this embodiment, the second power supply circuit 42 is connected to the first current path 21. Specifically, the second power supply circuit 42 is connected to the first path 21a. The second power supply circuit 42 is further connected to the second path 21b between the main switch 11 and the second input terminal 14b. Therefore, regardless of whether the main switch 11 is turned on or off, AC power is input to the second power supply circuit 42.

[0140] The second power supply circuit 42 includes a second Zener diode ZD2, a second capacitor C2, and a second diode D2. The cathode of the second Zener diode ZD2 is connected to the first path 21a and receives AC voltage from the AC power supply 100. The anode of the second Zener diode ZD2 is connected to the anode of the second diode D2 via a resistor R2. The cathode of the second diode D2 is connected to the second path 21b. The first end of the second capacitor C2 is connected to the cathode of the second Zener diode ZD2. The second end of the second capacitor C2 is connected to the anode of the second Zener diode ZD2. A second power having a second voltage Vc2 is generated mainly by the second Zener diode ZD2 and the second capacitor C2.

[0141] The electric work machine 1 further includes a rotation sensor 16. The rotation sensor 16 outputs a signal (hereinafter referred to as a speed signal) corresponding to the actual rotation speed of the rotor of the motor 15 (hereinafter referred to as the actual rotation speed). The speed signal is input to a motor control circuit 31.

[0142] The electric work machine 1 further includes a speed setting switch 13 and a set speed detection circuit 34. The speed setting switch 13 is provided, for example, on the motor housing 2 so that it can be operated by a user. The speed setting switch 13 is used to set a target speed of the motor 15. In this embodiment, the motor 15 is controlled to a constant rotation speed by a motor control circuit 31. Specifically, the motor control circuit 31 controls the rotation speed of the motor 15 so that the actual rotation speed of the motor 15 matches the target speed set by the speed setting switch 13.

[0143] In this embodiment, the speed setting switch 13 is configured to be able to change the target speed in stages, for example. That is, in this embodiment, the speed setting switch 13 is provided with, for example, a dial (not shown). The target speed changes depending on the position of this dial. By turning the dial, the user can set one of a plurality of set speeds (for example, five types) as the target speed. Note that the electric work machine 1 may also be configured to be able to set the target speed continuously. Furthermore, the speed setting switch 13 may be a type of switch other than a dial type.

[0144] The set speed detection circuit 34 outputs a target speed signal indicating the target speed set by the speed setting switch 13 to the motor control circuit 31. The motor control circuit 31 sets the target speed based on the target speed signal input from the set speed detection circuit 34.

[0145] The speed setting switch 13 includes a variable resistor (volume). A first terminal and a second terminal of the variable resistor are connected to the set speed detection circuit 34. The first terminal of the variable resistor is connected to the collector of a PNP-type third transistor Tr3 in the set speed detection circuit 34. A second voltage Vc2 is input to the emitter of the third transistor Tr3. The base of the third transistor Tr3 is connected to the power supply control circuit 40 via a resistor R4. The base and emitter of the third transistor Tr3 are connected via the resistor R3. The second terminal of the variable resistor is connected to a second ground line in the set speed detection circuit 34.

[0146] A setting disable signal SS may be input to the base of the third transistor Tr3 from the power supply control circuit 40. Normally, when the setting disable signal SS is not input, the third transistor Tr3 is turned on. Therefore, the second voltage Vc2 is divided into a value according to the state of the speed setting switch 13, and the divided value is input to the motor control circuit 31 as a target speed signal.

[0147] On the other hand, when the setting disable signal SS is input, the third transistor Tr3 is turned off. Therefore, the target speed signal becomes a zero signal having the potential of the second ground line, regardless of the state of the speed setting switch 13. This zero signal means that the target speed is set to zero. Therefore, when a zero signal is input from the set speed detection circuit 34, the motor control circuit 31 stops the motor 15. In other words, the power supply control circuit 40 can forcibly stop the motor 15 by outputting the setting disable signal SS.

[0148] The motor control circuit 31 executes motor control processing while the main switch 11 is on. The motor control circuit 31 can determine whether the main switch 11 is on or not based on the switch detection signal TR. The motor control processing is performed based on the zero-cross detection signal ZC, the speed setting signal, and the speed signal. The motor control processing includes a first processing and a second processing.

[0149] The first process includes obtaining a target speed based on the speed setting signal, and the second process includes generating a motor drive signal based on the actual rotation speed of motor 15 indicated by the speed signal input from rotation sensor 16 and the target speed obtained by the first process, so that the actual rotation speed coincides with the target speed.

[0150] More specifically, the second process executes so-called phase control. That is, since the motor drive switch 25 in this embodiment is a triac, it turns off when a zero cross occurs after it is turned on. Therefore, every time the motor control circuit 31 detects a zero cross timing using the zero cross detection signal ZC, it outputs a motor drive signal to the motor drive switch 25 at a drive timing (so-called conduction angle) based on the zero cross timing, thereby turning on the motor drive switch 25. The rotation speed of the motor 15 is determined according to the conduction angle.

[0151] (2-3) Power control processing by the power control circuit The power supply control process executed by the power supply control circuit 40 will be described with reference to Fig. 4. The power supply control circuit 40 (more specifically, the aforementioned CPU, for example) executes the power supply control process when started up by receiving the second power.

[0152] When the power supply control process starts, the power supply control circuit 40 determines in S110 whether the main switch 11 is on. This determination can be made based on the switch detection signal TR. If the main switch 11 is off, the process proceeds to S120.

[0153] If the main switch 11 is on, the power supply control circuit 40 executes the process of S160. If the main switch 11 is on when the power supply control circuit 40 is started, it is assumed that, for example, a user has connected the power plug 14 to the AC power supply 100 with the main switch 11 on. In such a case, the power supply control circuit 40 proceeds to S160 to prevent the motor 15 from rotating immediately.

[0154] In S160, the power supply control circuit 40 activates the restart suppression function. That is, in order to maintain the motor 15 in a stopped state, the second transistor Tr2 is turned on by outputting a short-circuit command. This stops the generation of the first power by the first power supply circuit 32. Furthermore, the setting disable signal SS is output, forcibly setting the target speed to zero.

[0155] In S170, the power supply control circuit 40 turns off the power supply control signal SD (i.e., keeps it at the L level), that is, stops outputting the power supply control signal SD, thereby keeping the power supply drive switch 35 off.

[0156] Although the generation of the first power is stopped when the second transistor Tr2 is simply turned on, the consumption of AC power by the first power supply circuit 32 can continue. That is, AC current can continue to be supplied to the second current path 22 from the AC power supply 100. In contrast, when the power supply drive switch 35 is turned off, the supply of AC current to the second current path 22 is stopped. This makes it possible to suppress heat generation caused by AC current flowing through the second current path 22.

[0157] In S180, the power supply control circuit 40 determines whether the main switch 11 is still on. If the main switch 11 is still on, the power supply control circuit 40 proceeds to the process of S160. If the main switch 11 is off, the power supply control circuit 40 executes the process of S190.

[0158] In S190, the power supply control circuit 40 cancels the restart suppression function. That is, the second transistor Tr2 is turned off by stopping the output of the short-circuit command. Furthermore, the output of the setting invalid signal SS is stopped. After processing S190, the power supply control circuit 40 proceeds to S120.

[0159] In S120, the power supply control circuit 40 turns off the power supply control signal SD, as in S170. In S130, the power supply control circuit 40 determines whether the main switch 11 is on. If the main switch 11 is off, the process proceeds to S120. If the main switch 11 is on, the process proceeds to S140.

[0160] In S140, the power supply control circuit 40 turns on the power supply control signal SD. That is, it outputs the power supply control signal SD as shown in Fig. 3. More specifically, it outputs the period signal SDo every time a zero cross is detected.

[0161] In S150, the power supply control circuit 40 determines whether the main switch 11 is on. If the main switch 11 is on, the process proceeds to S140. If the main switch 11 is off, the process proceeds to S120.

[0162] (2-4) Controller The controller 50 of this embodiment will be described with reference to FIGS. 5 to 9. The controller 50 is provided with most of the electrical system shown in FIG. 2. The controller 50 is disposed, for example, behind the motor 15 in the motor housing 2. A fan (not shown) rotated by the motor 15 is provided, for example, in front of the motor 15. Cooling air generated in the motor housing 2 by the rotation of the fan also hits the controller 50. The controller 50 can be cooled by this cooling air.

[0163] 5, the controller 50 includes a printed circuit board 51, a heat dissipation member 52, and a case 53. The case 53 is hollow and has a substantially rectangular parallelepiped shape. The case 53 houses the printed circuit board 51 and the heat dissipation member 52. The case 53 has an opening. The printed circuit board 51 and the heat dissipation member 52 are housed in the case 53 through the opening.

[0164] 6 and 7, the printed circuit board 51 includes an insulating substrate 55 and an electronic circuit 56. The insulating substrate 55 includes an insulator such as resin. The electronic circuit 56 includes various electronic components and various wirings. The various wirings include printed wirings formed on the insulating substrate 55.

[0165] The electronic circuit 56 includes at least a part of the electrical system shown in Fig. 2. The electronic circuit 56 may include any circuit in the electrical system shown in Fig. 2. In this embodiment, the electronic circuit 56 includes, for example, the motor drive circuit 30, the power supply control circuit 40, the first power supply circuit 32, the second power supply circuit 42, the switch detection circuit 33, the zero-cross detection circuit 41, the set speed detection circuit 34, the rotation sensor 16, and the second drive circuit 44.

[0166] The heat dissipation member 52 includes a first heat dissipation plate 61, a second heat dissipation plate 62, a third heat dissipation plate 63, a step portion 64, and a connecting portion (or bent portion) 65. The heat dissipation member 52 further includes a first leg 61a, a second leg 61b, a third leg 62a, and a fourth leg 62b. FIGS. 5 to 9 show some or all of these. In this embodiment, the first heat dissipation plate 61, the second heat dissipation plate 62, the third heat dissipation plate 63, the step portion 64, the connecting portion 65, the first leg 61a, the second leg 61b, the third leg 62a, and the fourth leg 62b are integrally formed. The heat dissipation member 52 is fixed to the insulating substrate 55 by the first leg 61a, the second leg 61b, the third leg 62a, and the fourth leg 62b.

[0167] The heat dissipation member 52 may be made of any material. The heat dissipation member 52 may be made of a metal including, for example, aluminum or copper. The heat dissipation member 52 may be made by any method. For example, the heat dissipation member 52 may be integrally formed by sheet metal processing a single metal plate. The heat dissipation member 52 may be integrally formed by a molding method such as casting or forging. The heat dissipation member 52 does not necessarily have to be integrally formed.

[0168] 6 and 7 exemplarily show a motor drive switch 25 and multiple electronic components including a resistor R1 and wiring. The resistor R1 is provided on a surface 55a of an insulating substrate 55 (hereinafter referred to as "substrate surface 55a"). In this embodiment, the resistor R1 is, for example, a so-called surface-mount chip resistor. The motor drive switch 25 is provided so as to be in direct contact with the heat dissipation member 52. More specifically, the motor drive switch 25 is fixed to the first heat dissipation plate 61, for example, by screws.

[0169] 6 and 7, the first heat dissipation plate 61 has a plate-like shape. In this embodiment, the plate surface (e.g., the surface facing the substrate surface 55a) of the first heat dissipation plate 61 is parallel to the substrate surface 55a. As shown in Fig. 7, the first heat dissipation plate 61 is disposed at a first distance h1 from the substrate surface 55a.

[0170] The second heat sink 62 has a plate-like shape. In this embodiment, the plate surface of the second heat sink 62 (e.g., the surface facing the substrate surface 55a) is parallel to the substrate surface 55a. As shown in Fig. 7, the second heat sink 62 is disposed at a second distance h2 from the substrate surface 55a. The second distance h2 is shorter than the first distance h1.

[0171] The third heat sink 63 has a plate-like shape. In this embodiment, the plate surface of the third heat sink 63 (e.g., the surface facing the substrate surface 55a) is parallel to the substrate surface 55a. As shown in FIG. 7, the third heat sink 63 is disposed at a third distance h3 from the substrate surface 55a. The third distance h3 is longer than the second distance h2. The third distance h3 may be the same as or different from the first distance h1. In this embodiment, the third distance h3 is equal to the first distance h1.

[0172] The step portion 64 integrally connects the first heat sink 61 and the second heat sink 62, which are at different distances from the substrate surface 55a. The second heat sink 62 is thermally coupled to the first heat sink 61 by the step portion 64. That is, heat can be conducted between the first heat sink 61 and the second heat sink 62 via the step portion 64.

[0173] The connecting portion 65 integrally connects the second heat sink 62 and the third heat sink 63 so that they are parallel to each other. In other words, the structure consisting of the second heat sink 62, the connecting portion 65, and the third heat sink 63 has a shape similar to a structure formed by folding (or bending) a single plate into a U-shape. The third heat sink 63 is thermally coupled to the second heat sink 62 by the connecting portion 65. In other words, heat can be conducted between the second heat sink 62 and the third heat sink 63 via the connecting portion 65.

[0174] As described above, the first power supply circuit 32 generates the first power from AC power supplied from the AC power supply 100. When the first power supply circuit 32 generates the first power, a DC current rectified by the diode D1 flows through the resistor R1. This DC current causes the resistor R1 to generate heat. Therefore, it is desirable to be able to efficiently dissipate the heat generated by the resistor R1 to the outside of the controller 50.

[0175] Even if the heat dissipation member 52 does not include the second heat dissipation plate 62 and the first heat dissipation plate 61 and the third heat dissipation plate 63 are thermally coupled, the heat generated from the resistor R1 can be conducted to the heat dissipation member 52 and dissipated from the heat dissipation member 52. Therefore, the heat dissipation member 52 does not need to include the second heat dissipation plate 62. However, in order to increase the efficiency of heat dissipation from the resistor R1, it is preferable that the distance between the resistor R1 and the heat dissipation member 52 is short.

[0176] Therefore, the heat dissipation member 52 of this embodiment includes, in addition to the first heat dissipation plate 61, a second heat dissipation plate 62 that is closer to the substrate surface 55a than the first heat dissipation plate 61. As a result, the distance between the resistor R1 and the heat dissipation member 52 (i.e., the distance from the second heat dissipation plate 62) is shorter than the distance when the second heat dissipation plate 62 is not included. Therefore, heat generated from the resistor R1 is more easily conducted to the heat dissipation member 52, and the efficiency of heat dissipation from the resistor R1 is improved.

[0177] Although not shown, the case 53 is filled with a filler material for waterproofing, moisture-proofing, and insulating the printed circuit board 51. The filler material may include, for example, epoxy resin or urethane resin. In this embodiment, the second heat sink 62 is immersed in the filler material. On the other hand, the first heat sink 61 and the third heat sink 63 are not immersed in the filler material and are exposed from the filler material. Therefore, heat generated from the resistor R1 is conducted to the second heat sink 62 via the filler material, and then further conducted from the second heat sink 62 to the first heat sink 61 and the third heat sink 63, and then released into the air.

[0178] Case 53 does not have to be filled with filler. Any amount of filler may be filled in case 53. For example, second heat sink 62 may not be immersed in the filler but may be exposed from the filler. Alternatively, for example, a part or all of first heat sink 61 and / or third heat sink 63 may be immersed in the filler.

[0179] (2-5) Correspondence between the embodiments and the present disclosure In this embodiment, the spindle 5 corresponds to an example of a drive mechanism in the present disclosure. The waiting time Ta in FIG. 3 corresponds to an example of a second time in the present disclosure. The period in FIG. 3 during which the period signal SDo is output corresponds to an example of a first time in the present disclosure. The main switch 11 corresponds to an example of a manual switch in the present disclosure. The rotation sensor 16 corresponds to an example of a signal output circuit in the present disclosure. The power plug 14 corresponds to an example of a power input unit in the present disclosure. The printed circuit board 51 corresponds to an example of a circuit board in the present disclosure. The insulating substrate 55 corresponds to an example of a substrate in the present disclosure.

[0180] 3. Other Embodiments Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the above-described embodiments and can be implemented in various modified forms.

[0181] (3-1) The power supply driving switch 35 may be a switch of a type other than a triac coupler. When the power supply driving switch 35 is a switch of a type other than a triac coupler, the power supply driving switch 35 may be turned on while the power supply control signal SD is input to the first power supply circuit 32, and may be turned off while the power supply control signal SD is not input to the first power supply circuit 32. In other words, both the on and off states of the power supply driving switch 35 may be controlled by the power supply control signal SD.

[0182] (3-2) In the power supply control process of Fig. 4, if it is determined in S180 that the main switch 11 is turned off, the process may proceed to S120. Then, after the process of S120 is executed, the process of S190 may be executed at any timing before the process of S140 is executed.

[0183] (3-3) The power supply control circuit 40 may output a power supply control signal SD having enough power to light up the LED 35b of the power drive switch 35. In this case, the power supply control signal SD may be supplied directly to the LED 35b without passing through the first drive circuit 36. In other words, the power supply control circuit 40 may directly drive the LED 35b.

[0184] (3-4) The heat dissipation member 52 provided in the controller 50 may have any shape. For example, a heat dissipation member 70 shown in FIG. 10 may be used instead of the heat dissipation member 52. The heat dissipation member 70 includes a first heat dissipation plate 71, a second heat dissipation plate 72, and a connecting portion 73. This heat dissipation member 70 can be considered to be a modified version of the heat dissipation member 52 of the above embodiment, for example, as follows. That is, the step portion 64 is removed from the heat dissipation member 52 of the above embodiment. Then, the first heat dissipation plate 61 and the third heat dissipation plate 63 are connected to integrate them.

[0185] Such a heat dissipation member 70 can be formed, for example, by folding (or bending) a portion of a single plate-like member having portions corresponding to the first heat dissipation plate 71 and the second heat dissipation plate 72 into a U-shape at the connecting portion 73. Such a heat dissipation member 70 also achieves the same effects as the heat dissipation member 52 of the above embodiment.

[0186] (3-5) The present disclosure is not limited to application to grinders, but can be applied to any electric work machine equipped with a motor driven by AC power. (3-6) Multiple functions possessed by one component in the above embodiments may be realized by multiple components, or one function possessed by one component may be realized by multiple components. Also, multiple functions possessed by multiple components may be realized by one component, or one function realized by multiple components may be realized by one component. Also, part of the configuration of the above embodiments may be omitted. Also, at least part of the configuration of the above embodiments may be added to or substituted for the configuration of another of the above embodiments. [Explanation of symbols]

[0187] 1...electric work machine, 5...spindle, 11...main switch, 12...power cord, 13...speed setting switch, 14...power plug, 15...motor, 16...rotation sensor, 21...first current path, 22...second current path, 25...motor drive switch, 30...motor drive circuit, 31...motor control circuit, 32...first power supply circuit, 33...switch detection circuit, 34...set speed detection circuit, 35...power drive switch, 35a...phototriac, 35b...LED, 40...power supply control circuit, 41...zero-cross detection circuit, 42...second power supply circuit, 50...controller, 51...printed circuit board, 52...heat dissipation member, 55...insulating substrate, 61,71...first heat sink, 62,72...second heat sink, 63...third heat sink, 64...step portion, 65,73...connecting portion, 100...AC power supply.

Claims

1. An electric work machine, a manual switch configured to be manually operated by a user of the electric working machine; a motor configured to be driven by AC power; a first current path configured to connect the motor to an AC power source and supply the AC power from the AC power source to the motor; a drive mechanism configured to removably mount a tool and to transmit rotation of the motor to the tool; a motor drive circuit configured to receive a first power to activate and control the supply of the AC power to the motor; a first power supply circuit, a second current path connected to the first current path and configured to receive the AC power from the first current path; a power generating circuit connected to the second current path and configured to receive the AC power from the first current path via the second current path and generate the first power from the AC power; a power supply drive switch that is provided on the second current path, configured to receive a power supply control signal, and configured to turn on the second current path when the power supply control signal is input, and to cut off the second current path when the power supply control signal is not input; a first power supply circuit comprising: a power supply control circuit configured to be activated by receiving a second power different from the first power, to output the power supply control signal to the first power supply circuit when a drive condition is satisfied, and to stop outputting the power supply control signal when the drive condition is not satisfied; a second power supply circuit provided separately from the first power supply circuit, connected to the first current path, configured to receive the AC power from the first current path, and configured to generate the second power from the AC power and supply the second power to the power supply control circuit; Equipped with the drive condition is satisfied when the manual switch is manually operated, and is not satisfied when the manual switch is not manually operated; Electric work equipment.

2. The electric operating machine according to claim 1, The first power supply circuit is configured to stop consumption of the AC power in response to input of the power supply control signal being stopped.

3. An electric work machine according to claim 1 or claim 2, The power supply drive switch is configured to interrupt the second current path in response to a voltage of the AC power becoming zero while the second current path is conducting.

4. An electric work machine as described in claim 3, The power switch is a bidirectional thyristor.

5. An electric work machine according to claim 3 or claim 4, The power supply control signal includes a pulse.

6. An electric work machine according to any one of claims 3 to 5, moreover, a zero-crossing detection circuit configured to detect zero-crossings of the voltage or current, including at least zero-crossings at rising edges of the voltage or current of the AC power; Equipped with The electric operating machine, wherein the power supply control signal includes a period signal that is output for a first period of time each time the zero crossing detection circuit detects at least the zero crossing during the rising edge.

7. An electric work machine as described in claim 6, The periodic signal includes a plurality of pulses at a fixed period.

8. An electric work machine according to claim 6 or claim 7, The power supply control circuit is configured to output the period signal after a second time has elapsed from the timing at which the zero-crossing is detected by the zero-crossing detection circuit.

9. An electric work machine according to any one of claims 6 to 8, the manual switch is provided on the first current path and is configured to conduct or interrupt the first current path in response to a manual operation by the user; the zero-crossing detection circuit is configured to receive the AC power from a portion of the first current path between the manual switch and the motor. Electric work equipment.

10. An electric work machine according to any one of claims 1 to 8, the manual switch is provided on the first current path and is configured to conduct or interrupt the first current path in response to a manual operation by the user; the first power supply circuit is connected to a first portion of the first current path between the manual switch and the motor and is configured to receive the AC power via the first portion. Electric work equipment.

11. An electric work machine as described in claim 10, the second power supply circuit is connected to a second portion in the first current path that is closer to the AC power supply than the manual switch, receives the AC power from the second portion, and generates the second power from the AC power.

12. An electric work machine according to any one of claims 9 to 11, The electric operating machine, wherein the drive condition is established when the first current path is made conductive by the manual switch after the power supply control circuit is started.

13. An electric work machine according to any one of claims 1 to 12, The motor drive circuit a motor drive switch that is provided on the first current path, configured to receive a motor drive signal, and configured to turn on or off the first current path in accordance with the motor drive signal; a motor control circuit configured to receive the first power and configured to be activated by receiving the first power to generate the motor drive signal; An electric work machine equipped with:

14. An electric work machine as described in claim 13, moreover, a signal output circuit configured to output a speed signal corresponding to the rotation speed of the motor; Equipped with The motor control circuit a first process of acquiring a target speed indicating a target of the rotation speed; a second process for generating the motor drive signal based on the rotation speed indicated by the speed signal output from the signal output circuit and the target speed obtained by the first process so that the rotation speed coincides with the target speed; The electric work machine is configured to perform the following:

15. An electric work machine according to any one of claims 1 to 14, moreover, a circuit board including a substrate and the first power supply circuit mounted on the substrate, the first power supply circuit including an electronic component that may generate heat loss; A heat dissipation member configured to conduct heat generated from the circuit board and dissipate the conducted heat, (i) a plate-shaped first heat sink arranged parallel to the substrate and spaced a first distance from the substrate in a substrate-orthogonal direction, the substrate-orthogonal direction being perpendicular to the substrate; and (ii) a plate-shaped second heat sink arranged parallel to the substrate and spaced a second distance from the substrate in a direction perpendicular to the substrate, the second heat sink being thermally coupled to the first heat sink, the second distance being shorter than the first distance; a heat dissipation member having An electric work machine equipped with:

16. An electric work machine as described in claim 15, The electric work machine, wherein the electronic component includes a resistor.

17. An electric work machine according to claim 15 or claim 16, The second heat sink is provided so that the electronic components are located in an area of ​​the surface of the substrate that faces the second heat sink.

18. An electric work machine according to any one of claims 15 to 17, At least a portion of the second heat sink faces the first heat sink along the direction orthogonal to the board.

19. An electric work machine as described in claim 18, the heat dissipation member further includes a connecting portion that thermally couples the first heat dissipation plate and the second heat dissipation plate, the first heat dissipation plate, the second heat dissipation plate, and the connecting portion are integrally formed as the same component; Electric work equipment.

20. An electric work machine according to any one of claims 15 to 17, the heat dissipation member further includes a plate-shaped third heat dissipation plate, The third heat sink is in direct contact with the second heat sink or is connected to the second heat sink via a first tangible member, thereby enabling thermal conduction between the third heat sink and the second heat sink. Electric work equipment.

21. An electric work machine as described in claim 20, the third heat sink is disposed parallel to the substrate and spaced a third distance from the substrate in a direction perpendicular to the substrate, the third distance is greater than the second distance; At least a portion of the third heat sink faces the second heat sink along the direction perpendicular to the board.

22. An electric work machine as described in claim 21, the heat dissipation member further includes a connecting portion that thermally couples the second heat dissipation plate and the third heat dissipation plate, the first heat dissipation plate, the second heat dissipation plate, the third heat dissipation plate, and the connecting portion are integrally formed as a single component. Electric work equipment.

23. An electric work machine according to claim 21 or claim 22, The electric work machine, wherein the third distance is equal to the first distance.

24. An electric work machine as described in claim 23, The electric operating machine, wherein the first heat dissipation plate and the third heat dissipation plate are arranged spaced apart on substantially the same plane.

25. An electric work machine according to any one of claims 15 to 24, The heat dissipation member is disposed so as to be spaced apart from the electronic components and not in contact with the electronic components.

26. An electric work machine according to any one of claims 15 to 25, the circuit board includes the first current path and the motor drive circuit; the motor drive circuit includes a motor drive switch provided on the first current path and configured to conduct or interrupt the first current path; The motor drive switch is in direct contact with the first heat sink or is connected to the first heat sink via a second tangible member, thereby enabling thermal conduction between the motor drive switch and the first heat sink. Electric work equipment.

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