Electric working machine

Abstract

To recognize disconnection of a signal line on a motor control part side, in an electric working machine constituted so as to output states of a plurality of sensors to the motor control part by the signal line common to the respective sensors.SOLUTION: The electric working machine includes a motor, a motor controller, an operation unit, and a position detector. The motor control unit controls driving of the motor, and the operation unit is moved to switch an operation mode of the motor. The position detection unit includes a first sensor, a first resistor, a second sensor, a second resistor, an output path, a pull-up resistor, and a pull-down resistor. One ends of the first and second resistors are connected to the first and second sensors, the other ends are connected at a connection point, and the output path outputs the detection signal from the connection point to the motor control unit via the signal line.SELECTED DRAWING: Figure 5

Description

[Technical Field]

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

[0002] Patent document 1 discloses an electric work machine that is configured to detect the operating position of an operating unit that switches operating modes using multiple Hall sensors, and to control the drive of a motor according to the operating mode that corresponds to the detected operating position.

[0003] Furthermore, Patent Document 1 describes that, on a sensor board, the output terminal of a first sensor is connected to a signal line, the signal line is connected to a power supply voltage via a first resistor, and the output terminal of a second sensor is connected to the signal line via a second resistor. In other words, by configuring the detection circuit of the sensor board in this way, the signal level of the signal line is set to a high level, a low level, or an intermediate level depending on the detection state of each sensor. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2023-125807 Summary of the Invention [Problem to be solved by the invention]

[0005] By configuring the detection circuit of the sensor board as described in Patent Document 1, the signal line that outputs the detection signal from the sensor board to the motor control unit can be made common to each sensor, thereby reducing the amount of wiring between the sensor board and the motor control unit.

[0006] However, signal lines are generally pulled down or pulled up on the motor control unit side, so if the detection circuit on the sensor board is configured as described above, when the signal line between the sensor board and the motor control unit is broken, the motor control unit may recognize the detection signal as low or high, and may not be able to recognize the break in the signal line.

[0007] One aspect of the present disclosure aims to enable the motor control unit to recognize a break in the signal line in an electric work machine configured to output the status of multiple sensors to a motor control unit via a signal line common to each sensor. [Means for solving the problem]

[0008] An electric work machine according to one aspect of the present disclosure includes a motor, a motor control unit, an operation unit, and a position detection unit. The motor control unit controls the driving of the motor. The operation unit is moved so as to switch the operation mode of the motor. The position detection unit detects the position of the operation unit and outputs a detection signal to the motor control unit via a signal line.

[0009] The position detection unit also includes a first sensor, a first resistor, a second sensor, a second resistor, an output path, a pull-up resistor, and a pull-down resistor. The first sensor detects a first position of the operating unit, and the second sensor detects a second position of the operating unit. The voltage levels of the output terminals of the first and second sensors are inverted to high or low depending on whether the position is being detected or not.

[0010] One end of the first resistor is connected to the output terminal of the first sensor, and one end of the second resistor is connected to the output terminal of the second sensor. The other end of the first resistor and the other end of the second resistor are connected at a connection point. The output path outputs a detection signal from the connection point to the motor control unit via a signal line.

[0011] The pull-up resistor has one end connected to the connection point and the other end connected to the power supply voltage. The pull-down resistor has one end connected to the connection point and the other end connected to the reference potential. The resistance values ​​of the first resistor and the second resistor are different from each other.

[0012] In the electric operating machine of the present disclosure configured as described above, when the first sensor or the second sensor detects a position, a current flows through the first resistor or the second resistor. Therefore, the potential at the connection point is a potential obtained by dividing the power supply voltage by the resistance value of the pull-up resistor and the resistance value of the parallel circuit of the pull-down resistor and the first resistor or the second resistor. Furthermore, because the resistance values ​​of the first resistor and the second resistor are different, the potential is different when the first sensor detects a position than when the second sensor detects a position. Furthermore, the potential is different from the high level corresponding to the power supply voltage or the low level corresponding to the reference potential.

[0013] Therefore, the signal level of the detection signal recognized by the motor control unit is different from the low level or high level recognized when there is a wire breakage. As a result, the motor control unit can accurately recognize not only the position of the operation unit detected by the first sensor or the second sensor, but also the breakage of the signal line, from the signal level of the detection signal. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is an explanatory diagram illustrating the appearance of an electric operating machine according to a first embodiment. [Figure 2] 1 is a cross-sectional view showing the internal configuration of an electric operating machine according to a first embodiment. [Figure 3] 1 is a block diagram showing the electrical configuration of an electric operating machine according to a first embodiment. [Figure 4] 3A and 3B are explanatory diagrams illustrating the position of an operation part detected by an operation position detection part of the first embodiment. [Figure 5] FIG. 2 is an explanatory diagram illustrating a circuit configuration of an operation position detection unit according to the first embodiment. [Figure 6]FIG. 6A is an explanatory diagram illustrating an operation of detecting an operation position in the first embodiment, and FIG. 6B is an explanatory diagram showing a speed mode determination threshold value used in the motor control circuit. [Figure 7] 4 is a flowchart showing a control process executed in the motor control circuit of the first embodiment. [Figure 8] 8 is a flowchart showing a speed mode detection process executed in S130 of FIG. 7. [Figure 9] 10 is an explanatory diagram illustrating a position of an operation part detected by an operation position detector according to the second embodiment. FIG. [Figure 10] FIG. 10 is an explanatory diagram illustrating a circuit configuration of an operation position detection unit according to a second embodiment. [Figure 11] FIG. 11A is an explanatory diagram illustrating an operation of detecting an operation position in the second embodiment, and FIG. 11B is an explanatory diagram showing a speed mode determination threshold value used in the motor control circuit. [Figure 12] 10 is a flowchart showing a speed mode detection process executed in a motor control circuit of a second embodiment. [Figure 13] FIG. 10 is an explanatory diagram illustrating a circuit configuration of an operation position detection unit according to a third embodiment. [Figure 14] FIG. 14A is an explanatory diagram illustrating an operation of detecting an operation position in the third embodiment, and FIG. 14B is an explanatory diagram showing a speed mode determination threshold value used in the motor control circuit. [Figure 15] 13 is an explanatory diagram illustrating a position of an operation part detected by an operation position detector according to a fourth embodiment. FIG. [Figure 16] FIG. 10 is an explanatory diagram illustrating a circuit configuration of an operation position detection unit according to a fourth embodiment. [Figure 17] FIG. 17A is an explanatory diagram illustrating an operation of detecting an operation position in the fourth embodiment, and FIG. 17B is an explanatory diagram showing a speed mode determination threshold value used in the motor control circuit. DETAILED DESCRIPTION OF THE INVENTION

[0015] [Summary of the embodiment] An embodiment may provide an electric power tool including at least one of the following: Feature 1: Motor. Feature 2: A motor control unit configured to control the driving of the motor. · Feature 3: An operating part that is moved to switch the motor's operating mode. Feature 4: Position detection unit that detects the position of the operating unit. Feature 5: The position detection unit outputs a detection signal to the motor control unit via a signal line. Feature 6: The position detection unit includes a first sensor that detects a first position of the operation unit. Feature 7: The position detection unit includes a first resistor having one end connected to the output terminal of the first sensor. Feature 8: The position detection unit includes a second sensor that detects a second position of the operation unit. Feature 9: The position detection unit includes a second resistor having one end connected to the output terminal of the second sensor. Feature 10: The position detection unit has a connection point that connects the other end of the first resistor and the other end of the second resistor. Feature 11: The position detection unit includes an output path that outputs a detection signal from the connection point via a signal line. Feature 12: The position detection unit includes a pull-up resistor having one end connected to the connection point and the other end connected to the power supply voltage. Feature 13: The position detection unit includes a pull-down resistor having one end connected to the connection point and the other end connected to a reference potential. Feature 14: The first sensor and the second sensor are configured such that the voltage level of the output terminal is inverted to a high level or a low level depending on whether the position is being detected or not. Feature 15: The resistance value of the first resistor and the resistance value of the second resistor are different from each other.

[0016] In an electric operating machine having at least Features 1 to 15, when the first sensor or the second sensor detects a position, a current flows through the first resistor or the second resistor. Therefore, the potential at the connection point is a potential obtained by dividing the power supply voltage by the resistance value of the pull-up resistor and the resistance value of the parallel circuit of the pull-down resistor and the first resistor or the second resistor.

[0017] Because the resistance values ​​of the first resistor and the second resistor are different, the potential at the connection point is different when the first sensor detects the position and when the second sensor detects the position, and the potential is also different from the high level corresponding to the power supply voltage or the low level corresponding to the reference potential.

[0018] Therefore, the signal level of the detection signal recognized by the motor control unit is different from the low level or high level recognized when a wire breaks, and therefore the motor control unit can accurately recognize not only the position of the operation unit detected by the first sensor or the second sensor, but also the break in the signal line, from the signal level of the detection signal.

[0019] Some embodiments may include the following in addition to or instead of at least one of features 1-15. Feature 16: At least one of the pull-up resistor and the pull-down resistor is disposed on the motor control unit side.

[0020] In the above configuration, for example, if the pull-up resistor is located on the motor control unit side and the pull-down resistor is located on the position detection unit side, the detection signal obtained on the motor control unit side will be high level when the signal line is broken. Conversely, if the pull-up resistor is located on the position detection unit side and the pull-down resistor is located on the motor control unit side, the detection signal obtained on the motor control unit side will be low level when the signal line is broken. Therefore, in either case, the motor control unit side can accurately detect a break in the signal line.

[0021] Some embodiments may include the following in addition to or instead of at least one of features 1-16. Feature 17: The pull-up resistor is located on the motor control unit side, and the pull-down resistor is located on the position detection unit.

[0022] In the above configuration, when a signal line is broken, the detection signal obtained on the motor control unit side goes high, allowing the motor control unit to accurately detect the break in the signal line. In addition, the presence of a pull-up resistor on the control side stabilizes the input to the motor control unit, preventing malfunction of the motor control unit due to external noise.

[0023] Some embodiments may include the following in addition to or instead of at least one of features 1-17. Feature 18: The resistance value of either the first resistor or the second resistor is 0Ω.

[0024] In the above configuration, the impedance on the position detection unit side is reduced when viewed from the motor control unit side, so that malfunction of the motor control unit due to external noise can be suppressed. Some embodiments may include the following in addition to or instead of at least one of features 1-18. Feature 19: The other end of the pull-down resistor is connected to the reference potential via a switching element. Feature 20: The switching element is configured to be conductive when a power supply voltage is supplied to the first sensor and the second sensor.

[0025] According to the above configuration, when the power line supplying the power supply voltage is broken, the detection signal obtained on the motor control unit side goes high, and therefore the motor control unit can detect the break in the power line from the signal level.

[0026] Some embodiments may include the following in addition to or instead of at least one of features 1-20. Feature 21: The pull-down resistor is located on the motor control unit side, and the pull-up resistor is located on the position detection unit. Feature 22: In the motor control unit, when a signal line is broken, the detection signal goes low corresponding to the reference potential, and when the signal line is not broken and normal, the detection signal goes high corresponding to the power supply voltage in a specific operating mode.

[0027] In the above configuration, the pull-down resistor is located on the motor control unit side, which stabilizes the input to the motor control unit and prevents malfunction of the motor control unit due to external noise. Furthermore, when a signal line is broken, the detection signal in the motor control unit goes low, allowing the motor control unit to accurately detect the break in the signal line.

[0028] Some embodiments may include the following in addition to or instead of at least one of features 1-22. Feature 23: The pull-up resistor and the pull-down resistor are both located on the motor control unit side. Feature 24: In the motor control unit, when a signal line is broken, the detection signal goes high, corresponding to the power supply voltage.

[0029] With the above configuration, the number of parts on the position detection unit side can be reduced, which prevents the position detection unit from becoming larger. Furthermore, when a signal line is broken, the detection signal goes high in the motor control unit, allowing the motor control unit to accurately detect the break in the signal line.

[0030] Some embodiments may include the following in addition to or instead of at least one of features 1-24. Feature 25: The resistance values ​​of the first resistor and the second resistor are not both 0 Ω.

[0031] In the above configuration, since the resistance values ​​of the first resistor and the second resistor are not 0 Ω, the signal level of the detection signal does not become low under normal circumstances when no disconnection occurs. Therefore, the low-level detection signal can be used for purposes other than position detection, such as determining whether a disconnection has occurred.

[0032] Some embodiments may include the following in addition to or instead of at least one of features 1-25. Feature 26: The other end of the pull-up resistor is directly connected to the power supply voltage, and the other end of the pull-down resistor is directly connected to the reference potential.

[0033] In the above configuration, the number of parts connected to the pull-up resistor or pull-down resistor can be reduced, and disconnections in signal lines or the like can be detected on the motor control unit side. Some embodiments may include the following in addition to or instead of at least one of features 1-26. Feature 27: The pull-down resistor has a resistance value that is one or more orders of magnitude higher than the first resistor, the second resistor, and the pull-up resistor. Feature 28: The ratio of the resistance values ​​of the first resistor, the second resistor, and the pull-up resistor is 1:4:2.

[0034] With this configuration, the signal level of the detection signal when a wire breaks can be set to low or high without affecting the signal level of the detection signal when the position detector detects the position, thereby preventing erroneous control in the motor controller due to external noise.

[0035] Furthermore, by setting the resistance ratio to 1:4:2, the signal level intervals of the detection signal when the position detector detects the position can be made uniform, which allows the position detector to more accurately detect the position of the operation unit, in other words, the motor controller to more accurately detect the operating mode.

[0036] Some embodiments may include the following in addition to or instead of at least one of features 1-28. Feature 29: The position detection unit includes a third sensor configured to detect a third position of the operation unit and to invert the voltage level of the output terminal to a high level or a low level depending on whether the third position is detected or not. Feature 30: The position detection unit includes a third resistor having one end connected to the output terminal of the third sensor and the other end connected to the connection point of the output path, the third resistor having a resistance value different from the resistance values ​​of the first resistor and the second resistor.

[0037] In an electric work machine having Features 29 and 30, when the third sensor detects that the operating part is in the third position, the potential of the connection point becomes a potential different from that when the position is detected by the first sensor or the second sensor. Therefore, the motor control part can recognize, from the signal level of the detection signal, not only the position of the operating part detected by the first sensor or the second sensor and a break in the signal line, but also the position of the operating part detected by the third sensor.

[0038] Examples of the above-mentioned power work machines include equipment configured to be used at work sites such as construction, manufacturing, gardening, and civil engineering, specifically, power tools for masonry, metalworking, and woodworking, power tools for gardening, and battery-powered wheelbarrows. Examples of the above-mentioned power tools include electric blowers, electric hammers, electric hammer drills, electric drills, electric screwdrivers, electric wrenches, electric grinders, electric circular saws, electric reciprocating saws, electric jigsaws, electric cutters, electric chainsaws, electric planers, electric nail guns (including tackers), electric hedge trimmers, electric lawn mowers, electric lawn clippers, electric grass cutters, electric cleaners, electric sprayers, electric spreaders, electric dust collectors, electric trowels, electric vibrators, electric rammers, electric compactors, electric pumps, electric pile drivers, electric concrete saws, electric screeds, and electric cut-off saws.

[0039] In some embodiments, the above features 1 to 28 may be combined in any manner. In some embodiments, any of the above features 1-28 may be omitted. Specific Exemplary Embodiments Certain exemplary embodiments are described below.

[0040] This particular exemplary embodiment provides an electric power tool 10 in the form of a driver drill. A driver drill is a type of power drill or power driver. However, this electric power tool 10 is merely an example, and the present disclosure may be applied to all types of electric power tools.

[0041] [First embodiment] <Configuration> As shown in Figures 1 and 2, the electric work machine 10 includes a housing 11. Various components are housed inside the housing 11. The housing 11 includes a motor housing section 14. The motor housing section 14 is provided at the rear of the housing 11 (on the left side in the figure).

[0042] The motor accommodating section 14 accommodates the motor 50. The motor 50 is a three-phase brushless motor. The housing 11 accommodates a gear case 31 in front of the motor accommodating section 14. The gear case 31 accommodates a reduction mechanism 30. The reduction mechanism 30 has an output shaft 7. Details of the reduction mechanism 30 will be described later.

[0043] The electric work machine 10 includes a chuck portion 16. The chuck portion 16 is provided to protrude from the tip (right side in the drawing) of the housing 11. The chuck portion 16 mounts a tool bit on the output shaft 7.

[0044] The electric operating machine 10 includes a torque selection unit 29. The torque selection unit 29 is provided on the rear side of the chuck unit 16. The torque selection unit 29 is a rotatable annular member that is rotated by the user to set the magnitude of torque (i.e., clamping force) in the clutch mode, which will be described later.

[0045] The electric work machine 10 includes an operation mode selection unit 27. The operation mode selection unit 27 is installed behind the torque selection unit 29. The operation mode selection unit 27 is a rotatable annular member that is rotated by the user to set the operation mode. In this embodiment, the operation modes include a drill mode and a clutch mode.

[0046] The drill mode is an operation mode for drilling holes in a workpiece. The clutch mode is an operation mode for tightening screws. When the clutch mode is selected, when the output torque reaches the torque magnitude selected via the torque selection unit 29, the clutch is disengaged and no torque greater than the selected torque magnitude is output.

[0047] The electric work machine 10 includes a grip 12 that is held by a user's hand. The grip 12 protrudes downward from the housing 11. The grip 12 includes a trigger 21. The trigger 21 includes a trigger operating portion 21a that is pulled by a user holding the grip 12. The trigger 21 also includes a speed setting portion 21b that includes a sliding resistor.

[0048] The electric work machine 10 is equipped with a forward / reverse selector switch 22. The forward / reverse selector switch 22 is provided above the trigger 21 and at the lower end of the housing 11. The forward / reverse selector switch 22 is a switch for switching the rotation direction of the motor 50 between forward and reverse. The above-mentioned operating modes may include a forward rotation mode and a reverse rotation mode. In the forward rotation mode, the motor 50 rotates in the forward direction, and in the reverse rotation mode, the motor 50 rotates in the reverse direction.

[0049] The electric work machine 10 is equipped with an illuminator 23. The illuminator 23 is provided above the trigger 21 and in front of the lower end of the housing 11. The illuminator 23 includes one or more light-emitting diodes (hereinafter referred to as LEDs), and illuminates the area in front of the electric work machine 10 when the trigger operating part 21a is pulled.

[0050] The electric operating machine 10 also includes a connection part 28 provided on the lower surface of the bottom of the grip 12. The connection part 28 is a sliding connection part, and the battery pack 160 is slid and connected to it.

[0051] The battery pack 160 includes a battery 162 with a predetermined voltage. The battery 162 is a rechargeable secondary battery, such as a lithium-ion battery. Furthermore, a remaining capacity display unit 24 is provided on the upper surface of the bottom of the grip 12. The remaining capacity display unit 24 includes one or more LEDs, and displays the remaining capacity of the battery 162.

[0052] <Deceleration mechanism> Next, the reduction mechanism 30 will be described in detail. 2, the reduction gear mechanism 30 includes internal gears 32A, 32B, and 32C, a plurality of planetary gears 33A, a plurality of planetary gears 33B, and a plurality of planetary gears 33C. The internal gears 32A, 32B, and 32C are fixed to the inner circumferential surface of the gear case 31. The plurality of planetary gears 33A revolve within the internal gear 32A. The plurality of planetary gears 33B revolve within the internal gear 32B. The plurality of planetary gears 33C revolve within the internal gear 32C.

[0053] The internal gears 32A, 32B, and 32C are arranged in this order from the motor 50 to the tip of the housing 11 along the direction of the rotational axis of the motor 50. Similarly, the plurality of planetary gears 33A, the plurality of planetary gears 33B, and the plurality of planetary gears 33C are arranged in this order from the motor 50 to the tip of the housing 11 along the direction of the rotational axis of the motor 50. The plurality of planetary gears 33A, the plurality of planetary gears 33B, and the plurality of planetary gears 33C are each arranged at predetermined angular intervals around the rotational axis of the motor 50.

[0054] The reduction gear mechanism 30 includes carriers 34A, 34B, and 34C. The carriers 34A, 34B, and 34C are arranged in this order along the rotational axis of the motor 50 and are rotatable around the rotational axis of the motor 50. The carrier 34A is arranged between the plurality of planetary gears 33A and the plurality of planetary gears 33B, rotatably supports the plurality of planetary gears 33A, and is engaged with the plurality of planetary gears 33B. The carrier 34B is arranged between the plurality of planetary gears 33B and the plurality of planetary gears 33C, rotatably supports the plurality of planetary gears 33B, and is engaged with the plurality of planetary gears 33C. The carrier 34C is arranged on the tip side of the plurality of planetary gears 33C, and rotatably supports the plurality of planetary gears 33C.

[0055] The planetary gears 33A are engaged with a pinion gear 50A fixed to the rotary shaft of a motor 50. An output shaft 7 is fixed to the carrier 34C. Since the electric operating machine 10 is provided with the reduction gear mechanism 30, the rotation of the motor 50 is reduced in three stages by the plurality of planetary gears 33A to 33C and carriers 34A to 34C before being transmitted to the output shaft 7.

[0056] The reduction gear mechanism 30 also includes a slide ring 35. The slide ring 35 is movable along the direction of the rotation axis of the motor 50 within the gear case 31. The internal gear 32B is fixed to the slide ring 35.

[0057] The slide ring 35 is physically connected to the gear operating unit 25. The gear operating unit 25 is provided on the upper surface of the housing 11. When the user moves the gear operating unit 25 in the forward / backward direction, the slide ring 35 moves along the rotation axis direction of the motor 50.

[0058] When the user operates the gear operating unit 25 to move the slide ring 35 from the front end position to the rear end position, the multiple planetary gears 33B and the carrier 34A are connected by the internal gear 32B. This causes the carrier 34A and the carrier 34B to rotate together. As a result, the speed reduction mechanism 30 reduces the rotation of the motor 50 in two stages using the multiple planetary gears 33A and 33C and the carriers 34A and 34C, and transmits the rotation to the output shaft 7.

[0059] Therefore, when the gear operating unit 25 is moved backward, the rotation of the motor 50 is decelerated by a first reduction ratio (i.e., two stages), and the output shaft 7 rotates at a high speed. Conversely, when the gear operating unit 25 is moved forward, the rotation of the motor 50 is decelerated by a second reduction ratio (i.e., three stages), and the output shaft 7 rotates at a low speed. The second reduction ratio is greater than the first reduction ratio.

[0060] Hereinafter, the operation mode set by the position of the gear operating unit 25 will be referred to as a speed mode, the speed mode in which the first reduction ratio is selected will be referred to as a high-speed gear mode, and the speed mode in which the second reduction ratio is selected will be referred to as a low-speed gear mode. Note that in this embodiment, the gear operating unit 25 is an example of an operating unit of the present disclosure.

[0061] Such switching of the reduction ratio is suitably performed by the user by operating the gear operating unit 25. When the rotation of the motor 50 is slowed down in three stages, the torque corresponding to the drive current is greater than when the rotation of the motor 50 is fastened down in two stages.

[0062] <Electrical configuration> Next, the electrical configuration of the electric operating machine 10 will be described with reference to FIG. The electric work machine 10 is equipped with a position sensor 52. The position sensor 52 has three Hall ICs arranged corresponding to the stators of each phase of the motor 50. The Hall ICs output a rotation detection signal to a position detection circuit 66 each time the rotor of the motor 50 rotates a predetermined angle. The position detection circuit 66 detects the rotational position of the motor 50 based on the rotation detection signal output from the position sensor 52. This position detection circuit 66 is mounted on the controller board 100.

[0063] The controller board 100 is disposed in the hollow portion at the bottom of the grip 12, between the remaining capacity display unit 24 on the top surface and the connection unit 28 on the bottom surface. In addition to the position detection circuit 66, the controller board 100 is also equipped with a motor drive circuit 62, a current detection circuit 64, a display circuit 68, a motor control circuit 70, and a power supply circuit 72.

[0064] The motor drive circuit 62 is a three-phase full-bridge circuit including three switching elements provided on the high side and three switching elements provided on the low side. The motor drive circuit 62 is connected between the battery pack 160 and the motor 50, receives power from the battery 162, and passes current through the windings of each phase of the motor 50. Each switching element of the motor drive circuit 62 is turned on or off in response to a control command output from a motor control circuit 70, which will be described later.

[0065] The current detection circuit 64 is a circuit that detects the current flowing through the windings of each phase of the motor 50 via the motor drive circuit 62. The current detection circuit 64 includes a resistor 64A that is provided in a current path that runs from the motor drive circuit 62 to the ground at the reference potential. The current detection circuit 64 detects the motor current from the voltage across the resistor 64A and the resistance value of the resistor 64A.

[0066] The motor control circuit 70 is an example of a motor control unit of the present disclosure, and is configured by a microcontroller (MCU) including a CPU, ROM, RAM, etc. Detection signals are input to the motor control circuit 70 from the current detection circuit 64 and the position detection circuit 66. The motor control circuit 70 is also connected to the speed setting unit 21b of the trigger 21, the operation mode selection unit 27, the torque selection unit 29, and an operation position detection unit 80, which will be described later.

[0067] The motor control circuit 70 sets a target rotation speed of the motor 50 based on input signals from these components, and outputs a control command to the motor drive circuit 62 so that the rotation speed of the motor 50 reaches the target rotation speed.

[0068] That is, the motor control circuit 70 drives the motor 50 by turning on and off the switching elements of the motor drive circuit 62. The motor control circuit 70 also controls the timing of turning on and off the switching elements of the motor drive circuit 62 in accordance with the rotational position of the motor 50 detected by the position detection circuit 66.

[0069] As a result, the motor control circuit 70 controls the motor current detected by the current detection circuit 64 to be a current corresponding to the target rotation speed, and the motor 50 is driven at the target rotation speed. The motor control circuit 70 also displays the remaining capacity of the battery 162 on the remaining capacity display 24 via the display circuit 68, and turns on the illuminator 23.

[0070] The power supply circuit 72 is a so-called regulator that generates a constant DC voltage (for example, 5 V) as a power supply voltage Vcc for operating the motor control circuit 70 using power supplied from the battery pack 160. This power supply voltage Vcc is also supplied to the internal circuits of the controller board 100 including the motor control circuit 70, and to peripheral circuits such as the speed setting unit 21b, the operation mode selection unit 27, the torque selection unit 29, and the operation position detection unit 80.

[0071] <Operation position detection unit> 4, the operation position detection unit 80 includes a sensor board 90 on which two Hall ICs, HS1 and HS2, are mounted. The sensor board 90 is fixed inside the housing 11 so as to face the back surface of the gear operation unit 25, which is opposite to the operation surface.

[0072] A permanent magnet 25A is provided on the back surface of the gear operating unit 25 at the center position in the movement direction of the gear operating unit 25. The permanent magnet 25A is arranged so that the operating surface side of the gear operating unit 25 is the south pole and the back surface side is the north pole.

[0073] On the other hand, on the sensor board 90, of the two Hall ICs HS1 and HS2, one Hall IC (hereinafter referred to as the first sensor) HS1 is disposed in a position facing the permanent magnet 25A when the gear operating unit 25 is in the forward low-speed position P1, and the other Hall IC (hereinafter referred to as the second sensor) HS2 is disposed in a position facing the permanent magnet 25A when the gear operating unit 25 is in the rear high-speed position P3.

[0074] As shown in FIG. 5, the sensor board 90 is connected to the controller board 100 via a power line L1, a signal line L2, a ground line L3, and a connector 102. The power supply line L1 is used to supply a power supply voltage Vcc from the controller board 100 to the power supply terminal T1 of the sensor board 90. The signal line L2 is used to transmit an operation position detection signal from the output terminal T2 of the sensor board 90 to the motor control circuit 70 of the controller board 100. The ground line L3 is used to connect the ground terminal T3, which serves as the reference potential of the sensor board 90, to the ground of the controller board 100, so as to match the reference potentials of the boards 90, 100.

[0075] The first sensor HS1 and the second sensor HS2 are operated by receiving a power supply voltage Vcc from a power supply terminal T1 and a ground terminal T3. 6A, when the gear operating unit 25 is at the low speed position P1, the first sensor HS1 detects the N pole of the permanent magnet 25A and turns on, causing the output to be at a low level (L) corresponding to the ground potential. Also, when the gear operating unit 25 is at the high speed position P3, the second sensor HS2 detects the N pole of the permanent magnet 25A and turns on, causing the output to be at a low level (L) corresponding to the ground potential.

[0076] On the other hand, when the gear operating unit 25 is not at the low speed position P1, the first sensor HS1 cannot detect the N pole of the permanent magnet 25A, so it is turned off and its output is at a high level (H) corresponding to the power supply voltage. Also, when the gear operating unit 25 is not at the high speed position P3, the second sensor HS2 cannot detect the N pole of the permanent magnet 25A, so it is turned off and its output is at a high level (H) corresponding to the power supply voltage.

[0077] 5, the signal line L2 between the sensor board 90 and the controller board 100 is connected to the power supply voltage Vcc via a pull-up resistor R1 on the controller board 100 side. Also, the signal line L2 is connected to the reference potential, which is the ground potential, via a pull-down resistor R4 on the controller board 100 side.

[0078] Furthermore, on the sensor board 90, one end of a first resistor R2 is connected to the output terminal for the detection signal of the first sensor HS1. Furthermore, one end of a second resistor R3 is connected to the output terminal for the detection signal of the second sensor HS2. Furthermore, the other ends of the first resistor R2 and the second resistor R3 are connected to a common connection point, and this connection point is connected to the output terminal T2 of the sensor board 90 via the output path for the detection signal.

[0079] Of the four resistors, the resistance value of the pull-up resistor R1 is set to, for example, 10 Ω, the resistance value of the first resistor R2 is set to, for example, 5.1 kΩ, and the resistance value of the second resistor R3 is set to, for example, 20 kΩ. In other words, the ratio of the resistance values ​​of the first resistor R2, the second resistor R3, and the pull-up resistor R1 is set to approximately 2:1:4. In contrast, the resistance value of the pull-down resistor R4 is set to, for example, 1 MΩ, which is one order of magnitude larger than the resistance values ​​of the three resistors R1, R2, and R3.

[0080] Therefore, as shown in FIG. 6B, when the gear operating unit 25 is in the low speed position P1, the signal level of the detection signal input to the motor control circuit 70 via the signal line L2 becomes a voltage level that is 1 / 3 of the power supply voltage Vcc (1 / 3H: 1.67V).

[0081] Furthermore, when the gear operating unit 25 is at the high speed position P3, the signal level of the detection signal input to the motor control circuit 70 via the signal line L2 becomes a voltage level of 2 / 3 of the power supply voltage Vcc (2 / 3H: 3.3V).

[0082] Furthermore, when at least one of the power line L1, the signal line L2, and the ground line L3 is disconnected, the signal level of the detection signal input to the motor control circuit 70 becomes high level (H: 5V).

[0083] Therefore, on the motor control circuit 70 side, it is possible to determine, from the signal level of the detection signal input from the operation position detection unit 80 via the signal line L2, whether the gear operation unit 25 is in the low speed position P1 or the high speed position P3, and whether wiring such as the signal line L2 is broken.

[0084] <Control processing> Next, the control process executed in the motor control circuit 70 will be described with reference to the flowcharts of FIGS.

[0085] The control process shown in FIG. 7 is repeatedly executed while the power supply voltage Vcc is supplied from the power supply circuit 72 to the motor control circuit 70 and the motor control circuit 70 is activated. When this control process is started, the motor control circuit 70 goes into a standby state in S110, waiting for the control process to be performed. Then, while in the standby state, the motor control circuit 70 determines in S120 whether the trigger operation unit 21a has been operated and the trigger 21 (more specifically, the speed setting unit 21b) has been turned on.

[0086] If it is determined in S120 that the trigger 21 is in the ON state, the process proceeds to S130, where the speed mode set by the gear operating unit 25 is detected based on the signal level of the detection signal input from the operating position detecting unit 80.

[0087] In this embodiment, the speed mode is set to either the high-speed gear mode or the low-speed gear mode depending on the position of the gear operating unit 25, so in S120 it is determined whether the speed mode is the high-speed gear mode or the low-speed gear mode. Also in S120, a disconnection determination is made for the signal line L2 or the like based on the detection signal input from the gear operating unit 25.

[0088] Then, in S120, based on the speed mode determination result or the disconnection determination result, it is set whether the motor 20 is driven in the high speed gear mode or the low speed gear mode, and the process proceeds to S140.

[0089] In S140, the control characteristics of motor 50 are set based on the speed mode setting in S130, the mode setting selected by operation mode selection unit 27, the torque setting selected by torque selection unit 29, etc. Then, based on the control characteristics and the drive command from speed setting unit 21b, a target rotation speed of motor 50 is set, and drive control is started to drive motor 50 so that the rotation speed of motor 50 becomes the target rotation speed.

[0090] Furthermore, when drive control of the motor 20 is started in S140, the process proceeds to S150, where it is determined whether or not the operation of the trigger operation unit 21a has stopped and the trigger 21 (more specifically, the speed setting unit 21b) has turned off. If it is determined in S150 that the trigger 21 has turned off, the process proceeds to S160, where a motor drive stop process is executed to stop the rotation of the motor 50, and the process proceeds to S110.

[0091] Next, the speed mode detection process in S130 is executed according to the procedure shown in FIG. As shown in FIG. 8, in the speed mode detection process, first, in S210, the signal level of the detection signal input from the operation position detection unit 80 (hereinafter, detection voltage V) is acquired.

[0092] Then, in S220, it is determined whether the detected voltage V acquired in S210 is less than the first threshold value: 3 / 6H (2.5V) shown in Fig. 6B. If it is determined in S220 that the detected voltage is less than the first threshold value: 3 / 6H (2.5V), the gear operating unit 25 is at the low speed position P1, so the process proceeds to S230, the speed mode is set to the low speed gear mode (low speed), and the speed mode detection process ends.

[0093] On the other hand, if it is determined in S220 that the detected voltage is equal to or greater than the first threshold value 3 / 6H (2.5V), the process proceeds to S240, where it is determined whether the detected voltage V acquired in S210 is less than the second threshold value 5 / 6H (4.16V). If it is determined in S240 that the detected voltage is less than the second threshold value 5 / 6H (4.16V), the gear operating unit 25 is at the high speed position P3, so the process proceeds to S250, the speed mode is set to the high speed gear mode (high speed), and the speed mode detection process ends.

[0094] Furthermore, if it is determined in S240 that the detected voltage is equal to or greater than the second threshold value: 5 / 6H (4.16V), the process proceeds to S260. In S260, it is determined that any of the wiring between the sensor board 90 and the controller board 100, such as the signal line L2, is broken, and the speed mode detection process ends.

[0095] Furthermore, in S260, because a detection signal cannot be normally acquired from the operation position detection unit 80 due to a disconnection of the signal line L2 or the like, the speed mode is set to the low-speed gear mode (low speed). This is to prevent the motor 50 from being driven in the high-speed gear mode when the reduction ratio of the reduction mechanism 30 is the second reduction ratio and is erroneously determined to be the first reduction ratio due to external noise or the like.

[0096] In other words, if the reduction ratio of the reduction mechanism 30 is erroneously determined due to external noise or the like and the motor 50 is driven in high-speed gear mode, the rotation speed of the output shaft 7 may increase abnormally. Therefore, in S260, the speed mode is set to low-speed gear mode (low speed). Therefore, according to this embodiment, it is possible to prevent the motor 50 from being erroneously controlled due to a break in the signal line L2 or the like, thereby preventing a decrease in safety.

[0097] <Effects> As described above, the electric operating machine 10 of this embodiment is provided with an operation position detection unit 80 that detects the operation position of the gear operation unit 25 that switches the reduction ratio of the reduction mechanism 30. The operation position detection unit 80 is provided with a first sensor HS1 and a second sensor HS2 for position detection. The detection results of each sensor are output from the operation position detection unit 80 to the motor control circuit 70 via the signal line L2 that is common to each sensor.

[0098] The detection results are input to the motor control circuit 70 as detection signals of a predetermined voltage level, but the signal level of the detection signal from each sensor is set to a different voltage level for each sensor. That is, the detection signal from each sensor has a different voltage level because it is determined by the resistance values ​​of the first and second resistors R2 and R3, which are provided between the output terminal of each sensor and the signal line L2, and the resistance values ​​of the pull-up resistor R1 and pull-down resistor R4.

[0099] Therefore, on the motor control circuit 70 side, the operating position of the gear operating unit 25, and ultimately the speed mode of the reduction mechanism 30, which is one of the operating modes of the electric work machine 10, can be detected from the signal level of the detection signal input via the signal line L2.

[0100] Furthermore, since the signal level of the detection signal is set by dividing the power supply voltage Vcc using each of the resistors, it will never be at a high level corresponding to the power supply voltage Vcc or a low level corresponding to the reference potential (ground potential).

[0101] In this embodiment, although both the pull-up resistor R1 and the pull-down resistor R4 are provided on the motor control circuit 70 side, the resistance value of the pull-down resistor R4 is greater than the resistance values ​​of the other resistors by at least one order of magnitude. Therefore, when a line such as the signal line L2 is broken, the signal level of the detection signal input to the motor control circuit 70 becomes high.

[0102] Therefore, the motor control circuit 70 can accurately recognize not only the operating position of the gear operating unit 25 but also breaks in the power line L1, signal line L2, ground line L3, etc. from the signal level of the detection signal input via the signal line L2.

[0103] Furthermore, since the ratio of the resistance values ​​of the first resistor R2, the second resistor R3, and the pull-up resistor R1 is 1:4:2, the signal level of the detection signal output from the operation position detector 80 can be set evenly between the reference potential and the power supply voltage. Therefore, on the motor control circuit 70 side, by setting a threshold value for determining the speed mode between each signal level, the operation position of the gear operation unit 25 can be determined with higher accuracy.

[0104] Furthermore, since the pull-up resistor R1 and the pull-down resistor R4 are provided on the motor control circuit 70 side, the number of parts provided in the operation position detection unit 80 can be reduced, and the operation position detection unit 80 can be made smaller.

[0105] [Second embodiment] In the above embodiment, the speed reduction mechanism 30 is configured to be able to switch the speed reduction ratio between two stages, and therefore the gear operating unit 25 is also able to move between a low-speed position and a high-speed position. For this reason, the operating position detection unit 80 has been described as detecting the low-speed position and the high-speed position of the gear operating unit 25. However, the speed reduction mechanism 30 may also be configured to be able to switch the speed reduction ratio between three stages or more.

[0106] Therefore, in this embodiment, the configuration of the operation position detection unit 80 and the speed mode detection process executed in the motor control circuit 70 when the speed reduction mechanism 30 is configured to be able to switch the reduction ratio between three stages will be described.

[0107] The configuration of the speed reduction mechanism 30 capable of switching the speed reduction ratio between three stages is described in Patent Document 1 and the like, and is a known technique, so a description of the configuration of the speed reduction mechanism 30 will be omitted. <Operation position detection unit> In the electric working machine 10 of this embodiment, the reduction mechanism 30 can switch the reduction ratio between three stages, so the gear operating unit 25 is moved to any one of a low-speed position P1, a high-speed position P3, and a medium-speed position P2 intermediate therebetween, as shown in Figure 9.

[0108] For this reason, as in the first embodiment, a permanent magnet 25A is provided on the back surface of the gear operating unit 25 at the center position in the movement direction of the gear operating unit 25. As in the first embodiment, the operation position detection unit 80 also includes a sensor board 90 on which a first sensor HS1 and a second sensor HS2 are mounted. The sensor board 90 is fixed inside the housing 11 so as to face the back surface of the gear operating unit 25, which is on the side opposite to the operation surface.

[0109] Furthermore, on the sensor board 90, the first sensor HS1 is positioned opposite the permanent magnet 25A when the gear operating unit 25 is in the low-speed position P1, and the second sensor HS2 is positioned opposite the permanent magnet 25A when the gear operating unit 25 is in the rear high-speed position P3.

[0110] 11A, when the gear operating unit 25 is in the low speed position P1, the first sensor HS1 is in the ON state and the second sensor HS2 is in the OFF state. Therefore, in this case, the output of the first sensor HS1 is at a low level and the output of the second sensor HS2 is at a high level.

[0111] When the gear operating unit 25 is at the high speed position P3, the first sensor HS1 is in the OFF state and the second sensor HS2 is in the ON state. Therefore, in this case, the output of the first sensor HS1 is at a high level and the output of the second sensor HS2 is at a low level.

[0112] When the gear operating unit 25 is in the medium speed position P2, the first sensor HS1 and the second sensor HS2 are both in the OFF state, so in this case, the outputs of the first sensor HS1 and the second sensor HS2 are both at a high level.

[0113] 10, similarly to the first embodiment, the sensor board 90 is connected to the controller board 100 via a power line L1, a signal line L2, a ground line L3, and a connector 102. In this embodiment, a first resistor R2, a second resistor R3, and a pull-down resistor R4 are mounted on the sensor board 90, and only the pull-up resistor R1 is provided on the controller board 100.

[0114] In the sensor substrate 90, one end of the first resistor R2 and one end of the second resistor R3 are connected to the output terminals of the first sensor HS1 and the second sensor HS2, respectively, and the other ends of the first resistor R2 and the second resistor R3 are connected to a common connection point. This connection point is then connected to the output terminal T2 of the sensor substrate 90 via an output path for the detection signal. Therefore, these configurations are the same as those in the first embodiment.

[0115] On the other hand, in the sensor substrate 90, one end of the pull-down resistor R4 is connected to an output path from a connection point where the other ends of the first resistor R2 and the second resistor R3 are connected, in other words, to an output terminal T2 that outputs a detection signal to a signal line L2, and the other end of the pull-down resistor R4 is connected to the switching element TR1.

[0116] The switching element TR1 is, for example, an NPN bipolar transistor, and the other end of the pull-down resistor R4 is connected to the collector of the switching element TR1. The emitter of the switching element TR1 is connected to a ground terminal T3, which serves as a reference potential. The base of the switching element TR1 is connected to the emitter via a resistor and also to the power supply terminal T1 via a resistor.

[0117] For this reason, the switching element TR1 is in the ON state when the power supply voltage Vcc is supplied from the controller board 100. Therefore, the other end of the pull-down resistor R4 is connected to the reference potential via the switching element TR1 only when the power supply voltage Vcc is supplied from the controller board 100.

[0118] The switching element TR1 does not necessarily have to be a bipolar transistor, but may be another transistor such as a FET, etc. In other words, the switching element TR1 may be any switching element that is turned on when receiving a power supply voltage.

[0119] The sensor substrate 90 is also provided with Zener diodes ZD1 and ZD2 and a capacitor C1. Of these, the Zener diode ZD1 has an anode connected to the ground terminal T3 and a cathode connected to the power supply terminal T1. The Zener diode ZD2 has an anode connected to the output terminal T2 of the sensor substrate 90 and a cathode connected to the power supply terminal T1.

[0120] The breakdown voltages of these two Zener diodes ZD1 and ZD2 are set to a constant voltage higher than the power supply voltage Vcc, for example, 7.5 V. Therefore, the voltages at the power supply terminal T1 and the output terminal T2 are limited to 7.5 V or less.

[0121] One end of the capacitor C1 is connected to the power supply terminal T1, and the other end is connected to the ground terminal T3. The capacitor C1, together with the Zener diodes ZD1 and ZD2, is used to absorb noise superimposed on the power supply line L1 and the signal line L2, and is set to have a capacitance of 0.1 μF and a breakdown voltage of 50 V, for example.

[0122] Therefore, in this embodiment, noise is absorbed by the capacitor C1 and the Zener diodes ZD1 and ZD2, and it is possible to prevent noise from entering the controller board 100 via the power line L1 and the signal line L2.

[0123] Next, the resistance value of the pull-up resistor R1 is set to, for example, 10 Ω, the resistance value of the first resistor R2 is set to, for example, 6.8 kΩ, the resistance value of the second resistor R3 is set to, for example, 0 Ω, and the resistance value of the pull-down resistor R4 is set to, for example, 20 kΩ.

[0124] This is because, as shown in FIG. 11A, the resistance value of the operation position detection unit 80 as seen from the motor control circuit 70 is 5.1 kΩ when the gear operation unit 25 is in the low speed position P1, 20 kΩ when the gear operation unit 25 is in the medium speed position P2, and 0 Ω when the gear operation unit 25 is in the high speed position P3.

[0125] 11A and 11B, when the gear operating unit 25 is in the low-speed position P1, the signal level of the detection signal input to the motor control circuit 70 becomes 1 / 3 of the voltage level of the power supply voltage Vcc (1 / 3H: 1.67V). When the gear operating unit 25 is in the medium-speed position P2, the signal level of the detection signal becomes 2 / 3 of the voltage level of the power supply voltage Vcc (2 / 3H: 3.3V). When the gear operating unit 25 is in the high-speed position P3, the signal level of the detection signal becomes a low level corresponding to the reference potential.

[0126] Furthermore, if at least one of the power line L1, signal line L2, and ground line L3 is broken, the resistance value of the operation position detection unit 80 as seen from the motor control circuit 70 becomes high impedance (Hi-Z). Since the pull-up resistor R1 is provided on the controller board 100, the signal level of the detection signal input to the motor control circuit 70 at the time of this break becomes a high level (H: 5V) corresponding to the power supply voltage Vcc.

[0127] Therefore, on the motor control circuit 70 side, it is possible to determine from the signal level of the detection signal input via the signal line L2 whether the gear operating unit 25 is in the low speed position P1, the medium speed position P2, or the high speed position P3, and whether wiring such as the signal line L2 is broken.

[0128] <Speed ​​mode detection process> Next, the speed mode detection process executed in the motor control circuit 70 will be described with reference to the flowchart of Fig. 12. Note that this speed mode detection process is the process executed in S130 of the control process shown in Fig. 7, similar to the first embodiment.

[0129] In the speed mode detection process of this embodiment shown in Fig. 12, first, in S310, the detected voltage V of the detection signal input from the operation position detection unit 80 is acquired. Then, in S320, it is determined whether the detected voltage V acquired in S310 is less than the first threshold value: 1 / 6H (0.83V) shown in Fig. 11B. If it is determined in S320 that the detected voltage is less than the first threshold value: 1 / 6H (0.83V), the gear operation unit 25 is at the high speed position P3, so the process proceeds to S330, the speed mode is set to the high speed gear mode (high speed), and the speed mode detection process ends.

[0130] On the other hand, if it is determined in S320 that the detected voltage is equal to or greater than the first threshold value 1 / 6H (0.83V), the process proceeds to S340, where it is determined whether the detected voltage V acquired in S310 is less than the second threshold value 3 / 6H (2.5V). If it is determined in S340 that the detected voltage is less than the second threshold value 3 / 6H (2.5V), the gear operating unit 25 is in the low speed position P1, so the process proceeds to S350, the speed mode is set to the low speed gear mode (low speed), and the speed mode detection process ends.

[0131] Furthermore, if it is determined in S340 that the detected voltage is equal to or greater than the second threshold value of 3 / 6H (2.5V), the process proceeds to S360, where it is determined whether the detected voltage V acquired in S310 is equal to or greater than the second threshold value of 3 / 6H (2.5V) and less than the third threshold value of 5 / 6 (4.16V). If it is determined in S360 that the detected voltage is equal to or greater than the second threshold value of 3 / 6H (2.5V) and less than the third threshold value of 5 / 6 (4.16V), the process proceeds to S370. In S370, it is determined that the gear operating unit 25 is at the medium speed position P2, the process proceeds to S370, the speed mode is set to the medium gear mode (medium speed), and the speed mode detection process ends.

[0132] Furthermore, if it is determined in S360 that the detected voltage is equal to or greater than the third threshold 5 / 6 (4.16V), the process proceeds to S380. Then, in S380, it is determined that any of the wiring between the sensor board 90 and the controller board 100, such as the signal line L2, is broken, and the speed mode detection process ends. Note that in S380, the speed mode is set to the low gear mode (low speed), similar to the process of S260 in the first embodiment.

[0133] <Effects> In this embodiment, the speed reduction mechanism 30 is configured to be able to switch the speed reduction ratio between three stages, and therefore the operation position of the gear operation unit 25 can also be switched between three stages: low speed position, medium speed position, and high speed position. In contrast, the operation position detection unit 80 is provided with two sensors, a first sensor HS1 and a second sensor HS2, as in the first embodiment, and detects the operation position of the gear operation unit 25 from the state of each sensor.

[0134] As in the first embodiment, the sensor board 90 of the operation position detection unit 80 is provided with a first sensor HS1, a first resistor R2, a second sensor HS2, and a second resistor R3, as well as a pull-down resistor R4. Therefore, the controller board 100 is provided with only the pull-up resistor R1 as a circuit component for position detection. Furthermore, the pull-down resistor R4 is connected to the reference potential via the switching element TR1 only when power is being supplied to the operation position detection unit 80.

[0135] Therefore, the operation position detector 80 outputs a detection signal of a voltage level (1 / 3H, 2 / 3H, L) corresponding to the operation position of the gear operation unit 25. Furthermore, when the power supply line L1, the signal line L2, or the ground line L3 is disconnected, the input from the signal line L2 to the motor control circuit 70 becomes high level (H).

[0136] Therefore, the motor control circuit 70 can detect the operating position of the gear operating unit 25, in other words, the speed mode, from the signal level of the detection signal input via the signal line L2. It can also detect breaks in the power line L1, signal line L2, ground line L3, etc.

[0137] In this embodiment, the resistance value of the first resistor R2 is set to 6.8 kΩ and the resistance value of the second resistor R3 is set to 0 Ω, but the same effect as above can be obtained even if the resistance value of the first resistor R2 is set to 0 Ω and the resistance value of the second resistor R3 is set to 6.8 kΩ. In other words, by setting the resistance value of either the first or second resistor R2, R3 to 0 Ω, the signal level of the detection signal at the low-speed position or the high-speed position becomes low, and the operating position of the gear operating unit 25 can be detected at three voltage levels different from the high level (high level) when the wire is broken.

[0138] [Third embodiment] In this embodiment, similar to the second embodiment, another configuration example of the operation position detection unit 80 when the reduction mechanism 30 is configured to be able to switch the reduction ratio between three stages will be described using Figures 13 and 14.

[0139] The operation position detection unit 80 includes a sensor board 90 on which a first sensor HS1 and a second sensor HS2 are mounted, and which is disposed opposite the rear surface of the gear operation unit 25, as in the second embodiment. 13, the circuit configuration of the sensor board 90 is basically the same as that of the first embodiment, but differs from the first embodiment in that the pull-up resistor R1 is mounted on the sensor board 90 of the operation position detector 80, rather than on the motor control circuit 70 side. The resistance values ​​of the pull-up resistor R1, the first resistor R2, the second resistor R3, and the pull-down resistor R4 are also the same as those of the first embodiment.

[0140] In this manner, in this embodiment, since only the pull-down resistor R4 is mounted on the controller board 100, when the power supply line L1 or the signal line L2 is broken, the signal level of the detection signal input to the motor control circuit 70 becomes low, as shown in Figures 14A and 14B.

[0141] When the gear operating unit 25 is in the low-speed position P1, the signal level of the detection signal becomes 1 / 3 of the power supply voltage Vcc (1 / 3H: 1.67V). When the gear operating unit 25 is in the high-speed position P3, the signal level of the detection signal becomes 2 / 3 of the power supply voltage Vcc (2 / 3H: 3.3V). When the gear operating unit 25 is in the medium-speed position P3, the signal level of the detection signal becomes a high level (H: 5V) corresponding to the power supply voltage.

[0142] 14B, the motor control circuit 70 can determine whether the gear operating unit 25 is in the low-speed position P1, the medium-speed position P2, or the high-speed position P3 from the signal level of the detection signal input via the signal line L2. It can also accurately determine whether wiring such as the signal line L2 is broken.

[0143] Therefore, the electric operating machine 10 of this embodiment can also achieve the same effects as those of the first and second embodiments. [Fourth embodiment] In the above-described first to third embodiments, the gear operating unit 25 has been described as having an operating position that can be switched between two or three stages, but the gear operating unit 25 has been described as having an operating position that can be switched between two or three stages.

[0144] However, even if the gear operating unit 25 can switch between four or more operating positions, the same effect as in each of the above embodiments can be obtained by increasing the number of sensors mounted on the sensor board 90 in the operating position detection unit 80.

[0145] Therefore, in this embodiment, the configuration of the operation position detector 80 when the speed reduction mechanism 30 is configured to be able to switch the speed reduction ratio between four stages will be described. In the electric operating machine 10 of this embodiment, the reduction gear mechanism 30 can switch the reduction ratio in four stages, so the gear operating unit 25 can be moved from the front to the rear to any one of a first position P01, a second position P02, a third position P03, and a fourth position P04, as shown in Fig. 15. For this reason, three sensors, a first sensor HS1, a second sensor HS2, and a third sensor HS3, are mounted on a sensor board 90 disposed opposite the rear surface of the gear operating unit 25.

[0146] Of these, the first sensor HS1 is disposed in a position facing the permanent magnet 25A of the gear operating unit 25 when the gear operating unit 25 is in the first position P01. The second sensor HS2 is disposed in a position facing the permanent magnet 25A when the gear operating unit 25 is in the second position P02. The third sensor HS3 is disposed in a position facing the permanent magnet 25A of the gear operating unit 25 when the gear operating unit 25 is in the third position P03.

[0147] 17A, when the gear operating unit 25 is in the first position P01, the first sensor HS1 is in the ON state, and the second and third sensors HS2 and HS3 are in the OFF state. When the gear operating unit 25 is in the second position P02, the second sensor HS2 is in the ON state, and the first and third sensors HS1 and HS3 are in the OFF state. When the gear operating unit 25 is in the third position P01, the third sensor HS3 is in the ON state, and the second and third sensors HS2 and HS3 are in the OFF state. When the gear operating unit 25 is in the fourth position P04, the first, second, and third sensors HS1, HS2, and HS3 are all in the OFF state.

[0148] As shown in FIG. 18, the sensor board 90 is connected to the controller board 100 via a power line L1, a signal line L2, a ground line L3, and a connector 102, similar to the above-described embodiments.

[0149] As shown in FIG. 16, the circuit configuration of the sensor board 90 is basically the same as that of the sensor board 90 of the second embodiment, and differs from the second embodiment in that a third sensor HS3 and a third resistor R4 are provided, and the pull-down resistor has the symbol R5.

[0150] Of these, the third sensor HS3 is connected in parallel to the first sensor HS1 and the second sensor HS2 so as to operate when a power supply voltage Vcc is supplied from the power supply terminal T1 and the ground terminal T3. One end of the third resistor R4 is connected to the output terminal of the third sensor HS3, and the other end is connected to the same connection point (in other words, the output path) as the first and second resistors R2 and R3.

[0151] In the operation position detection unit 80 of this embodiment configured as described above, similarly to the above embodiments, the signal level of the detection signal output to the motor control circuit 70 via the signal line L2 changes depending on the operation position of the gear operation unit 25. In other words, the voltage of the detection signal output to the motor control circuit 70 is a voltage obtained by dividing the power supply voltage Vcc (H) between the pull-up resistor R1 on the controller board 100 side and the combined resistance connected in parallel on the sensor board 90 side, as shown in Fig. 17A.

[0152] In this embodiment, as shown in FIG. 17B, the resistance value of the first resistor R2 is set to 0Ω, so that when the gear operating unit 25 is in the first position P01, the signal level of the detection signal becomes low.

[0153] In addition, the resistance values ​​of the other resistors R1, R3 to R5 are set so that when the gear operating unit 25 is in the second position P02 to the fourth position P04, the signal level of the detection signal is equal to a voltage obtained by dividing the power supply voltage Vcc into four equal parts.

[0154] That is, in this embodiment, when the gear operating unit 25 is in the second position P02, the signal level is ¼ voltage (¼H) of the power supply voltage Vcc. When the gear operating unit 25 is in the third position P03, the signal level is 2 / 4 voltage (2 / 4H) of the power supply voltage Vcc. When the gear operating unit 25 is in the fourth position P04, the signal level is ¾ voltage (¾H) of the power supply voltage Vcc.

[0155] In addition, since the pull-up resistor R1 is provided on the controller board 100, when the power supply line L1 or the signal line L2 is broken, the signal level of the detection signal becomes high level (H) corresponding to the power supply voltage Vcc.

[0156] 17B, ​​the motor control circuit 70 can determine whether the gear operating unit 25 is in the first position P01 to the fourth position P04 from the signal level of the detection signal input via the signal line L2. It can also accurately determine whether wiring such as the signal line L2 is broken.

[0157] Therefore, the electric operating machine 10 of this embodiment can also achieve the same effects as those of the first to third embodiments. Furthermore, even if the gear operating unit 25 can switch between five or more operating positions, it is possible to detect the operating position of the gear operating unit 25 in the same manner as in each of the above embodiments by increasing the number of sensors mounted on the sensor board 90 in the operating position detection unit 80.

[0158] In the fourth embodiment, a third sensor HS3 and a third resistor R4 are added to the sensor board 90 of the second embodiment shown in FIG. 10, so that the operating position of the gear operating unit 25, which can be switched between four stages, can be detected.

[0159] In contrast to this, even if a third sensor HS3 and a third resistor R4 are added to the sensor board 90 of the third embodiment shown in FIG. 13, the operating position of the gear operating unit 25, which can be switched between four stages, can be detected, as in the fourth embodiment.

[0160] [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.

[0161] For example, in the above embodiments, the sensors (first sensor HS1, second sensor HS2, and third sensor HS3) that detect the position of the operating unit are described as being configured with Hall ICs. However, these sensors do not necessarily need to be Hall ICs, and may be other sensors that can detect the position of the operating unit without contact, such as proximity sensors. Furthermore, these sensors may also be contact switches, such as microswitches, that switch between on and off states when the operating unit is in a predetermined position.

[0162] In the second and fourth embodiments, the capacitor C1 and the Zener diodes ZD1 and ZD2 are mounted on the sensor board 90 to absorb noise and prevent the noise from entering the controller board 100.

[0163] However, these electronic components for noise suppression do not necessarily need to be mounted on the sensor substrate 90. This allows for a reduction in the size of the operation position detection unit 80. Furthermore, these electronic components for noise suppression may be mounted on the sensor substrate 90 of the first and third embodiments.

[0164] In the above embodiments, multiple functions of one component may be realized by multiple components, or one function of one component may be realized by multiple components. Furthermore, multiple functions of multiple components may be realized by one component, or one function realized by multiple components may be realized by one component. Furthermore, part of the configuration of the above embodiments may be omitted. Furthermore, 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]

[0165] 25... gear operation unit, 50... motor, 70... motor control circuit, 80... operation position detection unit, HS1... first sensor, HS2... second sensor, L2... signal line, R1... pull-up resistor, R2... first resistor, R3... second resistor, R4... pull-down resistor, T2... output terminal.

Claims

1. A motor; a motor control unit configured to control the driving of the motor; an operating unit that is moved to switch the operation mode of the motor; a position detection unit configured to detect a position of the operation unit and output a detection signal to the motor control unit via a signal line; Equipped with The position detection unit a first sensor that detects a first position of the operation unit; a first resistor having one end connected to the output terminal of the first sensor; a second sensor that detects a second position of the operation unit; a second resistor having one end connected to the output terminal of the second sensor; an output path having a connection point connecting the other end of the first resistor and the other end of the second resistor, the output path outputting the detection signal from the connection point via the signal line; a pull-up resistor having one end connected to the connection point and the other end connected to a power supply voltage; a pull-down resistor having one end connected to the connection point and the other end connected to a reference potential; Equipped with the first sensor and the second sensor are configured such that the voltage levels of the output terminals are inverted to a high level or a low level depending on whether a position is being detected or not; The electric operating machine, wherein the resistance value of the first resistor and the resistance value of the second resistor are different from each other.

2. The electric operating machine according to claim 1, At least one of the pull-up resistor and the pull-down resistor is disposed on the motor control unit side.

3. The electric operating machine according to claim 2, The pull-up resistor is disposed on the motor control unit side, and the pull-down resistor is disposed on the position detection unit side.

4. The electric operating machine according to claim 3, The electric operating machine, wherein a resistance value of either the first resistor or the second resistor is 0Ω.

5. The electric operating machine according to claim 3 or 4, The other end of the pull-down resistor is connected to the reference potential via a switching element.

6. The electric operating machine according to claim 5, The switching element is configured to be conductive when the power supply voltage is supplied to the first sensor and the second sensor.

7. The electric operating machine according to claim 2, The pull-down resistor is disposed on the motor control unit side, and the pull-up resistor is disposed on the position detection unit side.

8. The electric operating machine according to claim 7, In the motor control unit, when the signal line is broken, the detection signal becomes a low level corresponding to the reference potential, and when the signal line is not broken and is in a normal state, the detection signal becomes a high level corresponding to the power supply voltage in a specific operating mode.

9. The electric operating machine according to claim 2, The pull-up resistor and the pull-down resistor are both disposed on the motor control unit side.

10. The electric operating machine according to claim 9, In the motor control unit, when the signal line is broken, the detection signal goes to a high level corresponding to the power supply voltage.

11. The electric operating machine according to any one of claims 7 to 10, The electric operating machine, wherein the resistance values ​​of the first resistor and the second resistor are not both 0 Ω.

12. An electric operating machine according to any one of claims 7 to 11, The other end of the pull-up resistor is directly connected to the power supply voltage, and the other end of the pull-down resistor is directly connected to the reference potential.

13. An electric operating machine according to any one of claims 7 to 12, The pull-down resistor has a resistance value that is one order of magnitude higher than the first resistor, the second resistor, and the pull-up resistor.

14. The electric operating machine according to claim 13, an electric operating machine, wherein a ratio of resistance values ​​of the first resistor, the second resistor, and the pull-up resistor is 1:4:2;

15. An electric operating machine according to any one of claims 1 to 13, The position detection unit further a third sensor configured to detect a third position of the operation unit, and to invert a voltage level of an output terminal to a high level or a low level depending on whether the third position is detected or not; a third resistor having one end connected to the output terminal of the third sensor and the other end connected to the connection point of the output path, the third resistor having a resistance value different from the resistance values ​​of the first resistor and the second resistor; An electric work machine equipped with:

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