Electric power machine

Abstract

The present application provides an electric working machine with more excellent operation performance. An electric working machine of one aspect of the present disclosure includes a motor, an operation unit, and a control unit. The control unit switches between a specific mode in which the rotational speed of the motor is increased and a mode in which the specific mode is not used, when a load of the motor is detected, based on reception of a prescribed signal. The control unit changes the rotational speed corresponding to the operation amount of the same operation unit in a speed region in which the rotational speed changes in correspondence with the operation amount of the operation unit, when the specific mode is used and when the specific mode is not used.

Description

Technical Field

[0001] This disclosure relates to electric working machines. Background Technology

[0002] The power tool described in Patent Document 1 has a soft no-load function. When the soft no-load function is activated, the power tool drives the motor at a constant predetermined speed, slower than the set target speed, until the tool is under load. When the tool is under load, the power tool accelerates the motor and drives it at the target speed.

[0003] Patent Document 1: Japanese Patent Application Publication No. 2018-202568

[0004] Consider a power tool equipped with a trigger that changes the motor speed in response to the amount of trigger pull. Consider adding a soft no-load function to this power tool. In this case, when the soft no-load function is disabled, the user can adjust the motor speed via the trigger, but when the soft no-load function is enabled, the user cannot adjust the motor speed via the trigger. Therefore, the user may perceive the power tool as having insufficient operability. Summary of the Invention

[0005] One aspect of this disclosure is to provide an electric working machine with superior operating performance.

[0006] One aspect of this disclosure involves an electric working machine comprising a motor, an operating unit, and a control unit. The operating unit is operated to drive the motor. The control unit is configured to control the rotational speed of the motor in accordance with the operation of the operating unit. The control unit is configured to switch between an active and inactive specific mode that increases the motor's rotational speed when a load on the motor is detected, based on the reception of a predetermined signal. When the specific mode is active or inactive, the control unit is configured to change the rotational speed within a speed range corresponding to the operation amount of the operating unit.

[0007] Even when a specific mode is active, the aforementioned electric working machine can change its rotational speed in accordance with the amount of operation performed by the operating unit. Furthermore, the rotational speed differs for the same amount of operation when the specific mode is active and when it is inactive. Therefore, the user can distinguish between the active and inactive modes through tactile feedback. This results in an electric working machine with superior operational performance. Attached Figure Description

[0008] Figure 1 This is a diagram showing the appearance of the electric working machine according to the first embodiment.

[0009] Figure 2 This is a block diagram showing the electrical structure of the electric working machine according to the first embodiment.

[0010] Figure 3 It represents the first mapping of the rotational speed relative to the trigger pull amount and dial position when the soft no-load is active, and the second mapping of the rotational speed relative to the trigger pull amount and dial position when the soft no-load is inactive.

[0011] Figure 4 It is a coordinate graph of the rotational speed relative to the command value of the trigger pull amount when the soft no-load is active and inactive in the first embodiment.

[0012] Figure 5 This is a flowchart illustrating the processing steps of the motor drive process in the first embodiment.

[0013] Figure 6 It is a timing diagram of the microcomputer power supply, main power switch, trigger opening and closing, target value of rotation speed, trigger pull amount, soft no-load setting, and motor drive status.

[0014] Figure 7 This is a coordinate graph of the rotational speed relative to the command value of the trigger pull amount when the soft no-load is effective in the second embodiment.

[0015] Figure 8 This is a coordinate graph of the rotational speed relative to the command value of the trigger pull amount when the soft no-load is invalid in the second embodiment.

[0016] Explanation of reference numerals in the attached figures:

[0017] 10… Electric working machine; 12… Trigger; 13… Main power switch; 14… Speed ​​adjustment dial; 20… Battery pack; 30… Microcomputer; 30a… CPU; 30b… ROM; 30c… RAM. Detailed Implementation

[0018] [Summary of Implementation Methods]

[0019] In one embodiment, the electric working machine may also include a motor, an operating unit, and a control unit.

[0020] The electric working machine of one embodiment may further include a storage unit. The storage unit may also store a first correspondence between the operation amount of the operating unit and a first rotational speed, and a second correspondence between the operation amount of the operating unit and a second rotational speed. The first rotational speed and the second rotational speed corresponding to the same operation amount of the operating unit may also be different. The control unit may also be configured to detect the load on the motor. The control unit may also be configured to, when a specific mode is valid, control the rotational speed to a first rotational speed, based on the first correspondence and the operation amount of the operating unit, before detecting a load, with a predetermined speed as the upper limit. The control unit may also be configured to, when a specific mode is invalid, control the rotational speed to a second rotational speed, based on the second correspondence and the operation amount of the operating unit. The electric working machine of one embodiment may omit any of these features.

[0021] When the electric working machine in one embodiment possesses all these features, and a specific mode is active, the user can manually change the rotational speed until the rotational speed reaches a predetermined speed before a load is detected. Thus, when the specific mode is active, the user can manually adjust the rotational speed in a low-speed range for tasks such as positioning the electric working machine relative to the workpiece. Furthermore, when the specific mode is inactive, the user can manually change the rotational speed regardless of whether a load is detected.

[0022] The electric working machine in one embodiment may further include a setting unit. The setting unit can also be operated to set a target value for the rotational speed. The specified speed may also be the lower of the target value set via the setting unit and a preset no-load speed. The second correspondence may also include multiple third correspondences different for each target value. The second rotational speed may also be capped at the target value and based on one of the multiple third correspondences corresponding to the target value set via the setting unit and the operation amount of the operating unit.

[0023] In one embodiment of the electric working machine, when a specific mode is invalid, the second rotational speed is based on one of a plurality of third correspondences corresponding to a set target value. Thus, when a specific mode is invalid, the user can manually adjust the rotational speed for each target value.

[0024] The first correspondence can also be constant regardless of the target value. And / or, the control unit can also be configured to, when a specific mode is effective, control the rotation speed to a third rotation speed obtained after detecting a load, with the target value as the upper limit, based on the first correspondence and the operation amount of the operation unit.

[0025] The first correspondence is constant regardless of the target value, and the control unit is configured such that, when a specific mode is active, after detecting a load, the rotational speed is controlled to a third rotational speed, which is an upper limit of the target value and is based on the first correspondence and the operation amount of the operation unit. In this case, after detecting a load, the motor's rotational speed is controlled based on the first correspondence, which is constant regardless of the target value. Therefore, when the specific mode is active, the user can manually change the rotational speed at the same rate of change, regardless of the target value. That is, when the specific mode is active, the burden on the user to adjust the rotational speed can be reduced, thereby improving work performance.

[0026] The control unit can also be configured to control the rotation speed to a target value set by the setting unit after detecting a load, when a specific mode is effective.

[0027] When a specific mode is active, the motor of this electric workpiece automatically rotates at the target speed regardless of the amount of operation by the operating unit after a load is detected. Therefore, when the specific mode is active, the user can work with the electric workpiece without adjusting the rotation speed.

[0028] The control unit can also be configured to continue controlling the rotation speed to a third rotation speed when a specific mode is active and no load is detected after the load has been detected.

[0029] Even after a temporary load is detected and then no longer detected, this electric machine can control its rotational speed to a third rotational speed. Therefore, it can suppress a decrease in rotational speed when the load is temporarily reduced during operation.

[0030] The control unit can also be configured to continue controlling the rotation speed to the target value when a specific mode is active, even after the load has been detected and no further load is detected.

[0031] Even after a temporary load is detected and then no longer detected, this type of electric motor can maintain its rotational speed at the target value. Therefore, it can suppress a decrease in motor rotational speed when the load is temporarily reduced during operation.

[0032] In one embodiment, the above features can be combined in any way. Additionally, in one embodiment, any of the above features may be omitted.

[0033] [Specific exemplary implementation methods]

[0034] Hereinafter, exemplary embodiments of the present disclosure will be described with reference to the accompanying drawings.

[0035] (1. First Implementation Method)

[0036] <1-1. Structure>

[0037] Reference Figure 1 The structure of the electric working machine 10 of the first embodiment will be described. The electric working machine 10 of this embodiment is a wire saw.

[0038] The electric working machine 10 includes a housing 11. The housing 11 supports a tool 15. The tool 15 is a saw blade (i.e., a wire saw blade) and is supported so that it can reciprocate relative to the housing 11. Additionally, the housing 11 houses a motor 50 (described later) and various circuits. The motor 50 is mechanically connected to the tool 15. The speed of the reciprocating motion of the tool 15 varies correspondingly to the rotational speed of the motor 50, and increases correspondingly to an increase in the speed of the motor 50.

[0039] Additionally, the outer casing 11 has a connecting portion 18. The connecting portion 18 is connected to the battery pack 20. The battery pack 20 has a rechargeable battery. The battery is, for example, a lithium-ion battery comprising multiple battery cells.

[0040] Additionally, a main power switch 13 is provided on the housing 11. The main power switch 13 is configured as a touch switch that can be operated by the user (specifically, pressed). Each time the main power switch 13 is operated, it switches between turning the power on and off of various circuits.

[0041] Additionally, a trigger 12 is provided on the housing 11. The trigger 12 is configured for user operation. Specifically, the trigger 12 is configured for the user to pull. The trigger 12 is configured to move from a first position to a second position. When the power to various circuits is turned on, if the user pulls the trigger 12, the motor 50 is driven. Moreover, in a predetermined driving mode, the rotational speed of the motor 50 changes corresponding to the amount of pull of the trigger 12. In this embodiment, the amount of pull of the trigger 12 is displayed in 12 trigger levels: 0, 1, 3, 5, 7, 9, 11, 13, 15, 17, 19, and 20. The amount of pull of the trigger 12 is not limited to 12 levels; it can also be displayed in multiple trigger levels. For example, the amount of pull of the trigger 12 can also be displayed in 10 or 20 trigger levels. The trigger level increases corresponding to the increase in the amount of pull of the trigger 12. In addition, in this embodiment, the trigger 12 corresponds to an example of the operating part of this disclosure.

[0042] Additionally, a speed adjustment dial 14 is provided on the housing 11. The speed adjustment dial 14 is configured for user operation to set a target value for the rotational speed of the motor 50. The speed adjustment dial 14 is a rotating component, and numbers "1" to "5" are marked along its circumference. Five target values ​​can be set via the speed adjustment dial 14. The number marked on the speed adjustment dial 14 is not limited to five; two or more are acceptable. The target values ​​set via the speed adjustment dial 14 are not limited to five; two or more are acceptable, for example, ten or twenty. The speed adjustment dial 14 outputs the dial position relative to a specified position on the housing 11 to the microcomputer 30. Figure 1 The target value is indicated by the triangle marking the position. The speed adjustment dial 14 is configured to rotate between a first limit position and a second limit position. At the first limit position, "1" is located at a designated position on the housing 11. At the second limit position, "5" is located at a designated position. In this embodiment, the speed adjustment dial 14 corresponds to an example of the setting unit of this disclosure. Furthermore, the speed adjustment dial 14 may also be, for example, a sliding speed adjustment dial.

[0043] Additionally, the speed adjustment dial 14 is operated by the user to switch between a first drive mode and a second drive mode. The drive mode switching operation involves reciprocating the speed adjustment dial 14 between a first extreme position and a second extreme position. That is, the drive mode switching operation is an operation where the speed adjustment dial 14 moves from the first extreme position to the second extreme position and then returns to the first extreme position, or vice versa. This reciprocating operation is not typically intended for setting a target value. Therefore, switching to an unwanted drive mode is prevented.

[0044] The first drive mode is a drive mode where soft no-load is effective. The second drive mode is a drive mode where soft no-load is ineffective. Soft no-load is a function of the electric work machine 10, which drives the motor 50 at a predetermined speed up to the maximum until a load is applied to the motor 50 (i.e., until a load is detected on the motor 50), and increases the rotational speed of the motor 50 when a load is applied to the motor 50 (i.e., when a load is detected on the motor 50). The predetermined speed is the lower of a set target rotational speed and the soft no-load speed. The soft no-load speed is a preset speed, and is a lower speed. That is, when soft no-load is effective, the increase in the rotational speed of the motor 50 is suppressed until a load is applied to the motor 50. Therefore, when the user positions the electric work machine 10 relative to a work object (e.g., wood), vibration of the electric work machine 10 or reaction force from the work object is suppressed. Thus, positioning of the electric work machine 10 becomes easier. In this embodiment, soft no-load corresponds to an example of a specific mode, and soft no-load speed corresponds to an example of no-load speed of this disclosure.

[0045] Next, refer to Figure 2 The electrical structure of the electric working machine 10 will be described. The electric working machine 10 includes a motor 50. The motor 50 is a brushless motor with three-phase coils having U-phase, V-phase, and W-phase.

[0046] In addition, the electric working machine 10 includes a position sensor 51. The position sensor 51 includes three Hall effect integrated circuits arranged corresponding to the stator of each phase of the motor 50. Whenever the rotor of the motor 50 rotates by a predetermined angle, the Hall effect integrated circuits output a rotation detection signal to the position detection circuit 52, which will be described later.

[0047] Additionally, the electric drive machine 10 includes a switch unit 130. The switch unit 130 includes a main power setting unit 13a. Corresponding to the operation of the main power switch 13, the main power setting unit 13a outputs a first power-on signal or a first power-off signal to the power circuit 41 and the switch input determination unit 320, described later. Whenever the main power switch 13 is operated, the signal output from the main power setting unit 13a switches between the first power-on signal and the first power-off signal.

[0048] The switching unit 130 includes a first speed setting unit 14a. The first speed setting unit 14a includes a sliding resistor and outputs a first resistance value signal, which represents a first resistance value corresponding to the dial position of the speed adjustment dial 14, to the speed command calculation unit 310, which will be described later.

[0049] The switch unit 130 includes a second speed setting unit 12a. When the trigger 12's actuation amount is greater than or equal to a predetermined actuation amount, the second speed setting unit 12a outputs a second power-on signal to the switch input determination unit 320. Conversely, when the trigger 12's actuation amount is less than a predetermined actuation amount, the second speed setting unit 12a outputs a second power-off signal to the switch input determination unit 320. Furthermore, the second speed setting unit 12a includes a sliding resistor and outputs a second resistance value signal, representing a second resistance value corresponding to the trigger 12's actuation amount, to the speed command calculation unit 310.

[0050] Additionally, the electric working machine 10 includes a working machine circuit 100. The working machine circuit 100 includes a power supply circuit 41. The power supply circuit 41 is connected to the battery pack 20. When a first turn-on signal is input to the power supply circuit 41, a predetermined power supply voltage Vcc is generated from the input power, thereby supplying the power supply voltage Vcc to various circuits within the working machine circuit 100, such as the microcomputer 30.

[0051] The working circuit 100 includes a motor driver 42. The motor driver 42 is a three-phase full-bridge circuit comprising three switching elements on the high-level side and three switching elements on the low-level side. The motor driver 42 is connected between the battery pack 20 and the motor 50, receiving power from the battery pack 20 and allowing current to flow in the windings of each phase of the motor 50. Corresponding to control commands output from the microcomputer 30 (described later), each switching element of the motor driver 42 is turned on or off.

[0052] The working machine circuit 100 includes a current detection circuit 43. The current detection circuit 43 detects the value of the current flowing into the motor 50 and outputs a detection signal corresponding to the detected current value to the current change detection unit 370, which will be described later.

[0053] The working machine circuit 100 includes a position detection circuit 52. The position detection circuit 52 detects the rotational position of the rotor of the motor 50 based on a rotational detection signal input from the position sensor 51. The position detection circuit 52 outputs a position signal corresponding to the detected rotational position to the microcomputer 30.

[0054] The working circuit 100 includes a microcomputer 30. The microcomputer 30 includes a CPU 30a, a ROM 30b, a RAM 30c, and I / O, etc. Various functions of the microcomputer 30 are implemented by the CPU 30a executing programs stored in a non-transitional physical recording medium. In this embodiment, the ROM 30b corresponds to the non-transitional physical recording medium. By executing the program, a method corresponding to the program is executed. Furthermore, one or more hardware components such as ICs may constitute part or all of the functions executed by the CPU 30a. Additionally, the microcomputer 30 may be composed of a single microcomputer or multiple microcomputers. The ROM 30b stores a first mapping and a second mapping, described later. Furthermore, the ROM 30b stores a setting indicating whether a soft idle is enabled or disabled. In this embodiment, the ROM 30b corresponds to an example of the storage unit of this disclosure.

[0055] As various functions, the microcomputer 30 includes a speed command calculation unit 310, a switch input determination unit 320, a soft no-load valid / invalid determination unit 330, a pulse width modulation generation unit (hereinafter, PWM generation unit) 340, a drive control unit 350, a soft no-load detection unit 360, a current change detection unit 370, a rotation speed calculation unit 390, and a display control unit 380. In this embodiment, the microcomputer 30 has all of the above-mentioned functions, but in other embodiments, one or more of the above-mentioned functions may be omitted.

[0056] The speed command calculation unit 310 calculates the rotational speed command value based on the input first resistance value signal and second resistance value signal, and the first mapping or the second mapping. That is, the speed command calculation unit 310 calculates the rotational speed command value based on the dial position of the speed adjustment dial 14 and the amount of trigger 12, and the first mapping or the second mapping.

[0057] The first mapping represents a first correspondence between the commanded trigger pull amount and the commanded rotational speed. The second mapping represents a second correspondence between the commanded trigger pull amount and the commanded rotational speed.

[0058] The first mapping is used when the soft idle load is valid. Figure 3 An example of the first mapping is shown. In the first mapping, the command value increases in response to an increase in the trigger pull amount. If the command value reaches the target value, the command value remains constant even if the trigger pull amount increases. Moreover, in the first mapping, the correspondence between the trigger pull amount and the command value of the rotation speed is equal even if the target values ​​are different. That is, even if the target values ​​are different, the same command value is calculated for the same pull amount until the command value reaches the target value.

[0059] For example, with the dial position "2", a target value of 1300 rpm is set, and with the dial position "4", a target value of 2500 rpm is set. Furthermore, even with either dial position "2" or "4", the command value increases at the same rate of increase corresponding to the increase in trigger pull amount within the trigger level range of 0 to 7. Moreover, with the dial position "2", if the trigger level changes to 9, the command value reaches the target value, and within the trigger level range of 9 to 20, the command value is fixed at the target value. Conversely, with the dial position "4", the command value increases corresponding to the increase in trigger pull amount until the trigger level changes to 15. Furthermore, if the trigger level changes to 17, the command value reaches the target value, and within the trigger level range of 17 to 20, the command value is fixed at the target value.

[0060] When soft no-load is active and during soft no-load execution (i.e., before load is detected), the speed command calculation unit 310 calculates a command value using a first mapping with a predetermined speed as the upper limit. The predetermined speed is the smaller of a target value and the soft no-load speed. The soft no-load speed is preset, and in this embodiment, it is 1400 rpm. Therefore, when the dial position is "1" or "2", the speed command calculation unit 310 calculates a command value using the first mapping with the target value as the upper limit. Furthermore, when the dial position is "3", "4", or "5", the speed command calculation unit 310 calculates a command value using the first mapping with the soft no-load speed as the upper limit.

[0061] In addition, during the process of soft idle being effective and soft idle being deactivated (i.e., after load is detected), the speed command calculation unit 310 calculates the command value using the first mapping with the target value as the upper limit.

[0062] The second mapping is used when the soft idle load is invalid. Figure 3 An example of the second mapping is shown. In the second mapping, the command value increases in response to an increase in the trigger pull amount, and if the command value reaches the target value, the command value becomes constant even if the trigger pull amount increases. Moreover, the second mapping includes multiple third mappings that differ for each target value. In the multiple third mappings, the command value increases in response to an increase in the target value for the same trigger pull amount.

[0063] exist Figure 4 The diagram shows a coordinate graph based on the first and second mappings and relative to the command value of the trigger pull. (See diagram for example.) Figure 4As shown, in this embodiment, the correspondences of the second mappings when the dial positions are "1" to "4" are different from the correspondences of the first mappings. Furthermore, in this embodiment, the correspondence of the second mapping when the dial position is "5" is equal to the correspondence of the first mapping.

[0064] return Figure 2 The speed command calculation unit 310 outputs the calculated rotational speed command value to the PWM generation unit 340. Additionally, the speed command calculation unit 310 outputs the first resistance value to the soft no-load effective / ineffective determination unit 330.

[0065] When a first power-on signal and a second power-on signal are input, the switch input determination unit 320 outputs a drive-on signal to the PWM generation unit 340, the soft no-load valid / invalid determination unit 330, and the display control unit 380. Conversely, when at least one of a first power-off signal and a second power-off signal is input, the switch input determination unit 320 outputs a drive-off signal to the PWM generation unit 340, the soft no-load valid / invalid determination unit 330, and the display control unit 380.

[0066] When a drive off signal is input, if the first resistance value signal shows a change equivalent to one cycle of the speed adjustment dial 14, the soft idle effective / ineffective determination unit 330 determines whether to switch from soft idle effective to ineffective, or from ineffective to effective. In this embodiment, the first resistance value signal showing a change equivalent to one cycle of the speed adjustment dial 14 is an example of a predetermined signal.

[0067] When the soft idle load valid / invalid determination unit 330 determines a switch from valid to invalid, it outputs an invalid signal to the PWM generation unit 340 and the display control unit 380. Conversely, when the soft idle load valid / invalid determination unit 330 determines a switch from invalid to valid, it outputs a valid signal to the PWM generation unit 340 and the display control unit 380.

[0068] The current change detection unit 370 detects the amount of change in current and the number of times the current increases based on the input detection signal.

[0069] When the change in current and the number of times the current increases exceed their respective thresholds, the soft no-load detection unit 360 detects the load acting on the motor 50. If the soft no-load detection unit 360 detects a load, it outputs a soft no-load release signal to the PWM generation unit 340.

[0070] The rotation speed calculation unit 390 calculates the rotation speed of the motor 50 based on the position signal input from the position detection circuit 52, and outputs the calculation result to the PWM generation unit 340.

[0071] The PWM generation unit 340 generates a PWM signal to drive the motor 50, so that the rotational speed of the motor 50 becomes the commanded value of the rotational speed. Specifically, the PWM generation unit 340 generates the PWM signal based on the input commanded value of the rotational speed, the calculated result of the input rotational speed, the input drive-on signal or drive-off signal, the input valid signal or invalid signal, and whether there is a soft no-load release signal. The PWM generation unit 340 outputs the generated PWM signal to the drive control unit 350.

[0072] The drive control unit 350 generates control commands based on the PWM signal output from the PWM generation unit 340. The control commands are to turn on or off the switches included in the motor driver 42. The drive control unit 350 outputs the generated control commands to the motor driver 42.

[0073] Additionally, the electric working machine 10 includes a reporting unit 60. The reporting unit 60 is an illuminator including at least one light-emitting diode (LED). Furthermore, the working machine circuit 100 includes a display circuit 61. The display control unit 380 controls the reporting of the reporting unit 60 via the display circuit 61 based on an input valid or invalid signal, an input drive-on signal, or a drive-off signal. When a valid signal and a drive-on signal are input, the display control unit 380 reports a soft idle being active via the reporting unit 60. For example, the display control unit 380 reports a soft idle being active by causing the reporting unit 60 to flash.

[0074] <1-2. Processing>

[0075] Next, refer to Figure 5 The flowchart illustrates the processing steps of the motor drive process executed by the microcomputer 30. When power is supplied to the microcomputer 30 and the power supply to the microcomputer is turned on, the microcomputer 30 begins this process.

[0076] First, in S10, the current setting of whether the soft idle is valid or invalid is read from ROM30b.

[0077] Next, in S20, the elapsed time is counted. Here, the time that the trigger 12 is kept in the closed state is measured by counting the elapsed time.

[0078] Next, in S30, it is determined whether a soft idle load handover operation has been performed. If it is determined that a soft idle load handover operation has been performed, the process proceeds to S40. If it is determined that a soft idle load handover operation has not been performed, the process proceeds to S50.

[0079] In S40, the soft idle setting is switched. That is, if the current soft idle setting is enabled, the soft idle setting is disabled, and the disabled setting is stored in ROM30b. Conversely, if the current soft idle setting is disabled, the soft idle setting is enabled, and the enabled setting is stored in ROM30b. Then, the process proceeds to S50.

[0080] In S50, it is determined whether the trigger 12 is in the open state. That is, it is determined whether a second power-on signal has been output from the second speed setting unit 12a. If it is determined that the trigger 12 is in the closed state, the process proceeds to S60.

[0081] In S60, it is determined whether the elapsed time counted in S20 is greater than the time threshold Tth. If the elapsed time is determined to be less than the time threshold Tth, the process returns to the step in S20. If the elapsed time is determined to be greater than the time threshold Tth, the process proceeds to the step in S70.

[0082] In S70, the power to the microcomputer is turned off, and the process ends.

[0083] Furthermore, in S50, if it is determined that trigger 12 is in the open state, the process proceeds to S80. In S80, corresponding to trigger 12 being in the open state, the elapsed time count is cleared, and the process proceeds to S90.

[0084] In S90, it is determined whether the current soft no-load is set to be valid. If it is determined that the soft no-load is set to be valid, the process proceeds to S100.

[0085] In S100, the command value of the rotational speed of the motor 50 is calculated based on the first mapping, the first resistance value signal, and the second resistance value signal.

[0086] Next, in S110, it is determined whether the soft no-load has been completely released. That is, it is determined whether a load on the motor 50 has been detected. The load on the motor 50 is the load acting on the motor 50 from the workpiece. If it is determined that the soft no-load has been completely released, the process proceeds to S150. If it is determined that the soft no-load has not been released, the process proceeds to S120.

[0087] In S120, it is determined whether the command value calculated in S100 is insufficient for the soft idle speed. If the command value is insufficient for the soft idle speed, the process proceeds to S150. If the command value is sufficient for the soft idle speed, the process proceeds to S130.

[0088] In S130, a soft no-load speed is set in the command value. As a result, during soft no-load execution, the rotational speed of motor 50 is suppressed below the soft no-load speed.

[0089] In addition, in S90, if it is determined that the soft idle is set to invalid, the process proceeds to S140.

[0090] In S140, the command value of the rotational speed of the motor 50 is calculated based on the second mapping, the first resistance value signal, and the second resistance value signal.

[0091] Next, in S150, a PWM signal is generated based on the instruction value calculated in any of S110, S130, and S140. Then, a control instruction is generated based on the generated PWM signal and output to the motor driver 42.

[0092] Next, in S160, it is determined whether the process is in the process of soft idle execution. If it is determined to be in the process of soft idle execution, the process proceeds to S170. If it is determined to be in the process of soft idle release, the process returns to S50.

[0093] In S170, it is determined whether to release the soft no-load. That is, if a load acting on motor 50 is detected based on the change in current and the number of times the current increases, it is determined that the soft no-load should be released. If the soft no-load is determined to be released, it is released. That is, the upper limit of the command value is used as the target value. If no load acting on motor 50 is detected, the soft no-load is maintained. Here, if the soft no-load is temporarily released, it will remain released even if no load acting on motor 50 is detected thereafter. That is, if the soft no-load is temporarily released, the command value will be calculated based on the first mapping with the target value as the upper limit, even if no load acting on motor 50 is detected thereafter. After processing in S170, the process returns to processing in S50.

[0094] exist Figure 6 The text shows that after execution Figure 5 The timing diagram shows the power supply of the microcomputer 30, the main power switch 13, the on / off state of the trigger 12, the target value of the rotation speed, the trigger pull amount, the soft no-load setting, and the motor drive state under the motor drive processing conditions.

[0095] At time t1, if the main power switch 13 is pressed, the first power-on signal is output, and the power supply to the microcomputer 30 is turned on. Then, the soft idle setting (which is valid here) is read. The dial position of the speed adjustment dial 14 is set to "5".

[0096] At time t2, if trigger 12 is pulled, a second power-on signal is output, and motor 50 begins to drive. From time t2 to time t4, the trigger pull amount increases, and from time t4 to time t6, the trigger pull amount is maintained at its maximum. From time t2 to time t3, the rotational speed of motor 50 increases, and at time t3, the rotational speed reaches its no-load speed (low speed). From time t3 to time t5, the rotational speed is maintained at its no-load speed.

[0097] Then, at time t5, a load is detected, and the soft no-load is released. With the release of the soft no-load, the rotational speed of motor 50 increases from the soft no-load speed to high speed. During the period from time t6 to time t7, the trigger pull amount decreases, and with the decrease in trigger pull amount, the rotational speed of motor 50 decreases. At time t7, trigger 12 is switched off, and a second power-off signal is output.

[0098] Then, at time t8, if the main power switch 13 is pressed and the first power off signal is output, the power supply of the microcomputer 30 will be turned off.

[0099] Next, at time t9, if the main power switch 13 is pressed, the first power-on signal is output, and the power of the microcomputer 30 is turned on.

[0100] Next, during the period from time t10 to time t11, trigger 12 is in the closed state, and speed adjustment dial 14 is reciprocated once. Simultaneously, at time t11, soft idle is set from active to inactive.

[0101] Next, at time t12, if trigger 12 is pulled, a second power-on signal is output, and motor 50 begins to drive. During the period from time t12 to time t13, the trigger pull amount increases, and the rotational speed of motor 50 increases accordingly. During the period from time t13 to time t14, the trigger pull amount is maintained at its maximum, and the rotational speed of motor 50 is maintained at its maximum speed. During the period from time t14 to time t15, the trigger pull amount decreases, and the rotational speed of motor 50 decreases accordingly. At time t15, trigger 12 becomes closed, and a second power-off signal is output.

[0102] <1-3. Effects>

[0103] According to the first embodiment described above, the following effects are achieved.

[0104] (1) Before the soft no-load is active and a load is detected, the rotational speed can be manually changed in the first mapping until the rotational speed reaches the specified speed. Furthermore, during the soft no-load active and soft no-load execution, the user can manually adjust the rotational speed in the low-speed range to perform tasks such as positioning the electric machine relative to the workpiece. Additionally, when the soft no-load is inactive, the rotational speed can be manually changed based on the second mapping regardless of whether a load is detected. Moreover, the correspondences of the second mappings when the dial positions are "1" to "4" are different from those of the first mapping, allowing the user to distinguish between active and inactive soft no-loads through tactile feedback.

[0105] (2) When the soft idle load is invalid, the command value is calculated based on the correspondence between the second mapping and the set target value. Thus, when the soft idle load is invalid, the rotation speed can be manually adjusted for each target value.

[0106] (3) When soft no-load is active and a load is detected, the command value is calculated based on the same correspondence, regardless of the set target value. Therefore, when soft no-load is active, the user can manually change the rotation speed at the same rate of change, regardless of the set target value. That is, when soft no-load is active, the burden on the user to adjust the rotation speed can be reduced, thereby improving working performance.

[0107] (4) Even if the load is no longer detected after a temporary load is detected, the motor 50 can still be rotated based on the command value calculated using the first mapping. Thus, when the load is temporarily reduced during operation, the reduction in rotational speed can be suppressed.

[0108] (2. Second Implementation)

[0109] <2-1. Differences from the first embodiment>

[0110] The basic structure of the second embodiment is the same as that of the first embodiment, therefore the differences will be described below. Furthermore, the same reference numerals as in the first embodiment denote the same structures, therefore reference will be made to the prior description.

[0111] In the first embodiment described above, during both the activation and deactivation of the soft idle load, the speed command calculation unit 310 uses a first mapping to calculate a command value for the rotational speed corresponding to the amount of pull of the trigger 12. In contrast, in the second embodiment, the speed command calculation unit 310 sets the target value of the rotational speed set via the speed adjustment dial 14 as the command value during both the activation and deactivation of the soft idle load, which differs from the first embodiment.

[0112] exist Figure 7The diagram shows a coordinate graph of the commanded rotational speed relative to the trigger pull amount when the soft no-load is active in this embodiment. Additionally, in Figure 8 The diagram shows a coordinate graph of the commanded rotational speed relative to the trigger pull amount when the soft no-load is invalid in this embodiment.

[0113] The soft idle speed is set to a value between the target value corresponding to dial position "1" and the target value corresponding to dial position "2". For example... Figure 7 As shown, when soft no-load is active, with the dial position "1", the command value increases to the target value corresponding to the trigger pull amount. Additionally, when soft no-load is active, with the dial positions "2" to "5", the command value increases to the soft no-load speed corresponding to the trigger pull amount. If soft no-load is released, each target value is set to the command value. Furthermore, even after soft no-load is released and no load is detected acting on motor 50, the target value is still set to the command value.

[0114] Therefore, when soft no-load is active, with the dial position between "2" and "5", the shifting range corresponding to the trigger pull amount corresponds to the low-speed range up to the soft no-load speed. On the other hand, as Figure 8 As shown, when the soft no-load is ineffective, the speed change region corresponding to the trigger pull amount is equivalent to the entire speed range up to each target value.

[0115] <2-2. Effects>

[0116] According to the second embodiment detailed above, the effects of the first embodiment described above (1) and (2) are achieved, and the following effects are obtained.

[0117] (5) When a soft no-load is active and a load is detected, the target speed is automatically set to the command value, regardless of the trigger pull amount. Thus, when a soft no-load is active and a load is detected, the user can operate the electric work machine 10 without adjusting the rotation speed.

[0118] (6) Even if the load is temporarily detected and then no longer detected, the motor can still rotate at the target value. Thus, when the load is temporarily reduced during operation, the reduction in rotational speed can be suppressed.

[0119] (3. Other implementation methods)

[0120] The embodiments of this disclosure have been described above, but this disclosure is not limited to the above embodiments and can be implemented in various modifications.

[0121] (a) In the above embodiments, the first mapping and the second mapping may also be stored in a memory other than ROM 30b built into the microcomputer 30. For example, the first mapping and the second mapping may also be stored in an external hard disk or removable medium configured to be connected to the microcomputer 30.

[0122] (b) The power working machine 10 is not limited to a wire saw. The power working machine 10 can be any power working machine equipped with a trigger. For example, the power working machine 10 can be a reciprocating saw, a hammer drill, a chainsaw, or other power tools, or a lawnmower or other gardening tools.

[0123] (c) Alternatively, multiple functions of one structural element in the above embodiments may be implemented by multiple structural elements, or one function of one structural element may be implemented by multiple structural elements. Alternatively, multiple functions of multiple structural elements may be implemented by one structural element, or one function implemented by multiple structural elements may be implemented by one structural element. Additionally, parts of the structure in the above embodiments may be omitted. Furthermore, at least parts of the structure in the above embodiments may be added to or replaced relative to the structures of other above embodiments.

[0124] (d) In addition to the electric working machine described above, this disclosure can also be implemented by various means such as a system with the electric working machine as a structural element, a program for enabling the microcomputer 30 to function, a non-transitional physical recording medium such as a semiconductor memory containing the program, and a motor driving method.

Claims

1. An electric working machine, wherein, have: motor; An operating unit, which is operable by the user, is used to drive the motor; A setting unit, used to set a target value for the rotational speed of the motor; and The control unit is configured to control the rotational speed of the motor in accordance with the operation of the operation unit, and to detect the load on the motor. The control unit is configured to switch between an active and inactive specific mode that increases the rotational speed of the motor when a load on the motor is detected, based on the reception of a predetermined signal. When the specific mode is active or inactive, the control unit changes the rotational speed within a speed range corresponding to the operation amount of the operation unit, specifically the rotational speed corresponding to the operation amount of the operation unit. The control unit is configured such that, (i) Where the specific mode is valid, (ia) Before the load is detected, the rotational speed is controlled at a predetermined speed as an upper limit, based on a first correspondence and the operation amount of the operating unit. The specified speed is equivalent to the lower of the target value set by the setting unit and the preset no-load speed. The first correspondence represents the relationship between the operation amount of the operating unit and the rotation speed, and the first correspondence is equal to the target value regardless of its value. (ib) After detecting the load, the rotation speed is controlled with the target value as the upper limit, and based on the first correspondence and the operation amount of the operation unit. The control unit is configured such that, (ii) In the event that the specific mode is invalid, Based on one of the third correspondences in the second correspondence relationship corresponding to the set target value, and the operation amount of the operation unit, the rotation speed is controlled with the target value as the upper limit. The second correspondence relationship includes the plurality of third correspondences that are different for each target value. The plurality of third correspondences respectively represent the correspondence between the operation amount of the operation unit and the rotation speed. Furthermore, the rotation speed for the same operation amount of the operation unit is different from the first correspondence relationship.

2. An electric working machine, wherein, have: motor; An operating unit, which is operable by the user, is used to drive the motor; A setting unit, which is used to set a target value for the rotational speed of the motor; and The control unit is configured to control the rotational speed of the motor in accordance with the operation of the operation unit, and to detect the load on the motor. The control unit is configured to switch between an active and inactive specific mode that increases the rotational speed of the motor when a load on the motor is detected, based on the reception of a predetermined signal. When the specific mode is active or inactive, the control unit changes the rotational speed within a speed range corresponding to the operation amount of the operation unit, specifically the rotational speed corresponding to the operation amount of the operation unit. The control unit is configured such that, (i) Where the specific mode is valid, (ia) Before the load is detected, the rotational speed is controlled at a predetermined speed as an upper limit, based on a first correspondence and the operation amount of the operating unit. The specified speed is equivalent to the lower of the target value set by the setting unit and the preset no-load speed. The first correspondence represents the relationship between the operation amount of the operating unit and the rotation speed, and the first correspondence is equal to the target value regardless of its value. (ib) After detecting the load, the rotational speed is controlled to the target value set via the setting unit. The control unit is configured such that, (ii) In the event that the specific mode is invalid, Based on one of the third correspondences in the second correspondence relationship that corresponds to the set target value, and the operation amount of the operation unit, the rotation speed is controlled with the target value as the upper limit. The second correspondence relationship includes the plurality of third correspondences that are different for each target value. The plurality of third correspondences respectively represent the correspondence between the operation amount of the operation unit and the rotation speed, and the rotation speed for the same operation amount of the operation unit is different from the first correspondence.

3. The electric working machine according to claim 1 or 2, wherein, The electric working machine also includes a storage unit, which stores the first correspondence and the plurality of third correspondences included in the second correspondence.

4. The electric working machine according to claim 1, wherein, The control unit is configured to continue controlling the rotation speed based on the first correspondence and the operation amount of the operation unit when the specific mode is active and the load is no longer detected after the load has been detected.

5. The electric working machine according to claim 2, wherein, The control unit is configured to continue controlling the rotation speed to the target value when the specific mode is active, even if the load is no longer detected after the load has been detected.

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