WO2016034136A1 - 电动工具的控制方法及控制系统、电动工具 - Google Patents

电动工具的控制方法及控制系统、电动工具 Download PDF

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Publication number
WO2016034136A1
WO2016034136A1 PCT/CN2015/088893 CN2015088893W WO2016034136A1 WO 2016034136 A1 WO2016034136 A1 WO 2016034136A1 CN 2015088893 W CN2015088893 W CN 2015088893W WO 2016034136 A1 WO2016034136 A1 WO 2016034136A1
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WO
WIPO (PCT)
Prior art keywords
motor
preset
parameter
time
power tool
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/CN2015/088893
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English (en)
French (fr)
Inventor
邓强
牟国良
张士松
饶越
徐静涛
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Positec Power Tools Suzhou Co Ltd
Original Assignee
Positec Power Tools Suzhou Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from CN201410709443.8A external-priority patent/CN104656551B/zh
Application filed by Positec Power Tools Suzhou Co Ltd filed Critical Positec Power Tools Suzhou Co Ltd
Publication of WO2016034136A1 publication Critical patent/WO2016034136A1/zh
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
    • B25B—TOOLS OR BENCH DEVICES NOT OTHERWISE PROVIDED FOR, FOR FASTENING, CONNECTING, DISENGAGING, OR HOLDING
    • B25B21/00—Portable power-driven screw or nut setting or loosening tools; Attachments for drilling apparatus serving the same purpose
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
    • B25B—TOOLS OR BENCH DEVICES NOT OTHERWISE PROVIDED FOR, FOR FASTENING, CONNECTING, DISENGAGING, OR HOLDING
    • B25B23/00—Details of, or accessories for, spanners, wrenches, screwdrivers
    • B25B23/14—Arrangement of torque limiters or torque indicators in wrenches or screwdrivers
    • G—PHYSICS
    • G05—CONTROLLING; REGULATING
    • G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
    • G05B19/00—Program-control systems
    • G05B19/02—Program-control systems electric
    • G05B19/04—Program control other than numerical control, i.e. in sequence controllers or logic controllers

Definitions

  • the invention relates to the field of power tools, and in particular to a method for controlling a power tool.
  • the invention also relates to a control system to which the control method is applied.
  • the invention also relates to a power tool to which the control system is applied.
  • Existing power tools such as electric impact wrenches, provide current through a loaded power source to drive the motor to rotate, thereby rotating the working head to tighten or remove the threaded fastener.
  • the present invention provides a method of controlling a power tool that can be completely released on a bolt without removing the nut.
  • the present invention provides a control method for a power tool, wherein the power tool includes a motor and an output shaft that connects the motor, and the control method includes the following steps: detecting the representation Outputting a parameter x of the axle load; determining that the output shaft load is reduced to be equal to or less than a preset load according to the parameter x meeting a preset condition, thereby changing the rotational speed of the motor.
  • the parameter x is one of a current value supplied to the motor, an output torque value of the output shaft, or an acceleration value of the power tool;
  • the preset condition includes: the parameter X is equal to or smaller than a first preset threshold .
  • the parameter x is one of a current value supplied to the motor, an output torque value of the output shaft, or an acceleration value of the power tool;
  • the preset condition includes: within a third preset time period, the parameter X The duration is equal to or less than the first preset threshold.
  • the parameter x is one of a current value supplied to the motor, an output torque value of the output shaft, or an acceleration value of the power tool;
  • the preset condition includes: the parameter is greater than or equal to a second preset threshold Decrease to less than or equal to the first preset threshold.
  • the specific manner of the step of changing the rotation speed of the motor comprises: starting the power tool motor as the starting time, acquiring the target time when the parameter x meets the preset condition; when the target time is after the preset time After the first preset period of time, the motor is turned off, or the motor is turned off after the motor is operated for a preset number of turns, or the motor speed is reduced.
  • the specific manner of the step of changing the rotation speed of the motor comprises: starting the power tool motor as the starting time, acquiring the target time when the parameter x meets the preset condition; when the target time is before the preset time , immediately shut down the motor.
  • the present invention further provides a control method for a power tool, wherein the power tool includes a motor and an output shaft that connects the motor, and the control method includes the following steps: detecting a parameter x indicating an output shaft load; Determining a preset function f(x) of the parameter x; determining that the output shaft load is reduced to be equal to or less than a preset load according to the preset function f(x) according to a preset condition, thereby changing the rotational speed of the motor.
  • the preset function f(x) is an N-th derivative of the parameter x, and the N is a positive integer; the preset condition is: the value of the preset function f(x) is equal to or smaller than a preset derivative threshold. .
  • the parameter x is a current value supplied to the motor or an output torque value of the output shaft.
  • the specific manner of the step of changing the rotational speed of the motor is: acquiring the preset function f(x) The target time when the preset condition is met, the target time starts from the start of the power tool motor; when the target time is after the preset time, the motor is turned off after the first preset time period, or the motor is preset to run. Turn off the motor after the number of turns, or reduce the motor speed.
  • the step of changing the rotation speed of the motor is: acquiring a target moment when the preset function f(x) meets the preset condition, and the target moment starts from a start of the power tool motor;
  • the present invention further provides a control method for a power tool, wherein the power tool includes a motor and an output shaft that connects the motor, and the control method includes the following steps: detecting a parameter x indicating an output shaft load; calculating a parameter x a preset function f(x); determining that the output shaft load is reduced to be equal to or less than a preset load according to the parameter x and its preset function f(x) according to a preset condition, thereby changing the rotation speed of the motor .
  • the parameter x is a current value supplied to the motor
  • the preset function f(x) is a first derivative value of the parameter x
  • the preset condition includes: the current value supplied to the motor is less than the first value The preset threshold value, the first derivative value of the current value supplied to the motor is negative.
  • the step of changing the rotation speed of the motor is: taking the power tool motor as the starting time, and acquiring the target time when the parameter x and the preset function f(x) meet the preset condition;
  • the target time is after the preset time, the motor is turned off after the first preset time period, or the motor is turned off after the motor is operated for a preset number of turns, or the motor speed is reduced.
  • the step of changing the rotation speed of the motor is: taking the power tool motor as the starting time, and acquiring the target time when the parameter x and the preset function f(x) meet the preset condition; Immediately shut down the motor when the target time is before the preset time.
  • the parameter x for indicating the output shaft load is detected.
  • control method further comprises the following steps of detecting a parameter x for indicating an output shaft load: a preset speed control demand instruction set, which includes a plurality of speed adjustment demand instructions, each speed control demand instruction corresponding to the A specific way of changing the speed of the motor; obtaining a user speed demand request; and confirming the specific manner of the step of changing the motor speed according to the user speed demand request.
  • the step of changing the motor speed is specifically: controlling the motor to periodically switch between forward rotation and reverse rotation.
  • the parameter is a current supplied to the motor
  • the first preset threshold is a current value of the power tool in an idle state.
  • the power tool is an impact wrench
  • the impact wrench is selectively forward or reverse
  • the control method performs a function according to the parameter x or the parameter x.
  • At least one of f(x) meets a preset condition to determine that the output shaft load is reduced to be equal to or less than a preset load, thereby changing the rotational speed of the motor.
  • the electric tool is an impact wrench
  • the impact wrench can selectively loosen or tighten the nut
  • the control method performs according to the parameter x or parameter x.
  • At least one of the functions f(x) meets a preset condition to determine that the output shaft load is reduced to be equal to or less than a preset load, thereby changing the rotational speed of the motor.
  • the present invention also provides another method of controlling an impact wrench, the impact wrench comprising a motor and an output shaft connecting the motor, the impact wrench selectively loosening or tightening the nut, the impact wrench loose
  • the control method comprises the steps of: detecting a parameter characterizing the output shaft load; determining whether the release condition is satisfied, the release condition characterizing that the nut is switched from the tightened state to the released state; When the release condition is satisfied, change the speed of the motor.
  • the release condition is that the parameter x, or at least one of the functions f(x) of the parameter x meets a preset condition.
  • the control method of the power tool provided by the invention can completely loosen the nut and the bolt without separating the nut and the bolt, and the user can manually separate the nut and the bolt according to the requirement, so as to satisfy the user only need to loosen the nut.
  • the special working conditions of the nut are opened.
  • the present invention provides a control system for a power tool that is fully detachable from the bolt but does not remove the nut.
  • the present invention provides a control system for a power tool, wherein the power tool includes a motor and an output shaft that connects the motor, the control system includes: a detection module that detects a parameter x indicating an output shaft load; Control module, including: parameter determination sub-module, according to The parameter x meets a preset condition to determine that the output shaft load is reduced to be equal to or less than a preset load; the first motor shift sub-module receives a signal of the parameter determination sub-module, thereby changing the rotational speed of the motor.
  • the parameter x is one of a current value supplied to the motor, an output torque value of the output shaft, or an acceleration value of the power tool;
  • the preset condition includes: the parameter X is equal to or smaller than a first preset threshold.
  • the parameter x is one of a current value supplied to the motor, an output torque value of the output shaft, or an acceleration value of the power tool;
  • the preset condition includes: within a third preset time period, the parameter X The duration is equal to or less than the first preset threshold.
  • the parameter x is one of a current value supplied to the motor, an output torque value of the output shaft, or an acceleration value of the power tool;
  • the preset condition includes: the parameter is greater than or equal to a second preset threshold Decrease to less than or equal to the first preset threshold.
  • the first motor shifting sub-module includes: a first time acquiring unit, wherein the power tool motor is started as a starting time, and the target time when the parameter x meets the preset condition is acquired; the time determining unit determines the target Whether the time is after the preset time; the motor control unit, when the target time is after the preset time, shut down the motor after the first preset time, or control the motor to run the preset number of turns, then shut down the motor, or reduce the motor speed .
  • the first motor shifting sub-module includes: a first time acquiring unit, wherein the power tool motor is started as a starting time, and the target time when the parameter x meets the preset condition is acquired; the time determining unit determines the target Whether the time is before the preset time; the motor control unit immediately shuts down the motor when the target time is before the preset time.
  • the present invention also provides a control system for another power tool, wherein the power tool includes a motor and an output shaft that connects the motor, the control system includes: a detection module that detects a parameter for indicating an output shaft load
  • the second calculation module calculates a preset function f(x) of the parameter x;
  • the second control module includes: a function determination sub-module, and determines that the preset function f(x) meets a preset condition
  • the output shaft load is reduced to be equal to or less than a preset load; the second motor shift sub-module receives a signal that determines the sub-module, thereby changing the rotational speed of the motor.
  • the preset function f(x) is an N-th derivative of the parameter x, and the N is a positive integer; the preset condition is: the value of the preset function f(x) is equal to or smaller than a preset derivative threshold. .
  • the parameter x is a current value supplied to the motor or a torque value of the output shaft.
  • the second motor shifting sub-module includes: a second time acquiring unit, wherein the power tool motor is started as a starting time, and the target time when the function f(x) meets the preset condition is acquired; the time determining unit , determining whether the target time is after the preset time; the motor control unit, after the target time is after the preset time, shutting down the motor after the first preset time period, or controlling the motor to operate the preset number of turns, then shutting down the motor, or Reduce the motor speed.
  • a second time acquiring unit wherein the power tool motor is started as a starting time, and the target time when the function f(x) meets the preset condition is acquired
  • the time determining unit determining whether the target time is after the preset time
  • the motor control unit after the target time is after the preset time, shutting down the motor after the first preset time period, or controlling the motor to operate the preset number of turns, then shutting down the motor, or Reduce the motor speed.
  • the second motor shifting sub-module includes: a second time acquiring unit, wherein the power tool motor is started as a starting time, and the target time when the function f(x) meets the preset condition is acquired; the time determining unit , to determine whether the target time is before the preset time; the motor control unit, when the target time is before the preset time, immediately shut down the motor.
  • the present invention also provides a control system for another power tool, wherein the power tool includes a motor and an output shaft that connects the motor, the control system includes: a detection module that detects a parameter for indicating an output shaft load
  • the third computing module calculates a preset function f(x) of the parameter x;
  • the third control module includes: a parameter function determining sub-module, according to the parameter x and its preset function f(x) meeting a preset condition It is determined that the output shaft load is reduced to be equal to or less than a preset load; the third motor shift sub-module receives the signal of the parameter determination sub-module, thereby changing the rotational speed of the motor.
  • the parameter x is a current value supplied to the motor
  • the preset function f(x) is a first derivative value of the parameter x
  • the preset condition includes: the current value of the supply motor is smaller than the first pre-predetermined The threshold value is set, and the first derivative value of the current value supplied to the motor is negative.
  • the third motor shifting sub-module includes: a third time acquiring unit, wherein the power tool motor is started as a starting time, and the target time when the parameter x and the function f(x) meet the preset condition are acquired; The time determination unit determines whether the target time is after the preset time; the motor control unit turns off the motor after the first preset time period after the target time is after the preset time, or controls the motor to operate after the preset number of turns Motor, or reduce motor speed.
  • the third motor shifting sub-module includes: a third time acquiring unit, wherein the power tool motor is started as a starting time, and the target time when the parameter x and the function f(x) meet the preset condition are acquired; The time determination unit determines whether the target time is before the preset time; the motor control unit immediately shuts down the motor when the target time is before the preset time.
  • the detecting module starts detecting a parameter x for indicating the output shaft load.
  • the control system further includes a preset module, where the preset module includes: an instruction preset sub-module, configured to preset a speed control demand instruction set, and includes a plurality of speed control demand instructions, each speed adjustment requirement
  • the instruction corresponds to a specific manner of the step of changing the rotation speed of the motor;
  • the instruction acquisition sub-module is configured to acquire a user speed adjustment demand instruction;
  • the instruction matching sub-module is configured to confirm the change of the motor rotation speed according to the user speed adjustment demand instruction.
  • the motor shifting sub-module controls the motor to periodically switch between forward rotation and reverse rotation.
  • the parameter is a current supplied to the motor
  • the first preset threshold is a current value of the power tool in an idle state.
  • control system of the power tool provided by the invention can completely loosen the nut and the bolt without separating the nut and the bolt, and the user can manually separate the nut and the bolt according to the requirement, so as to satisfy the user only need to loosen the nut.
  • the special working conditions of the nut are opened.
  • the present invention provides a power tool that can be fully released on a bolt without removing the nut.
  • the present invention provides a power tool including: a power source; a motor that acquires power of the power source to provide rotational power; an output shaft that acquires rotational power of the motor and outputs;
  • the system is electrically connected to the motor and the power source.
  • the power tool further comprises: a system activation component for operatively starting the control system.
  • the power tool is an impact wrench
  • the impact wrench selectively loosens or tightens a nut
  • the impact wrench performs a loosening nut action, operating the system starting component to activate the control system.
  • the power tool is an impact wrench, and the impact wrench can be selectively rotated or reversed.
  • the system activation component is operated to activate the control system when the impact wrench performs a reverse action.
  • the power tool provided by the invention can completely loosen the nut and the bolt without separating the nut and the bolt, and the user can manually separate the nut and the bolt according to the requirement, so that the user only needs to loosen the nut. Special working conditions.
  • the invention also provides a power tool, which can automatically monitor whether a slip phenomenon occurs, and take corresponding measures when the slip phenomenon occurs to reduce the damage of the slip head to the working head, the screw head, the surface of the workpiece and the like.
  • the present invention provides a power tool including: a working head; a motor that drives the working head to output power after starting; a power source to power the motor; a detecting component, a detecting and characterizing device The parameter of the working head load is output and the detection signal is output; and the control module receives the detection signal, and determines that the working head intermittently outputs power when the load of the working head is decreased according to the detection signal.
  • the present invention also provides another power tool, the power tool, driving a fastener embedded in a workpiece, the power tool comprising: a working head; a motor, driving the working head to output power after starting; Providing power to the motor; detecting a component, detecting a parameter characterizing the load of the working head and outputting a detection signal; and a control module determining whether the working head is separated from the fastener according to the detection signal, when determining As a result, the torque transmission to the working head is interrupted, and the criterion for separating the working head from the fastener is that the load of the working head is reduced.
  • control module shields reception of the detection signal within a preset time after the motor is started.
  • control module determines that the load of the working head is reduced when the amount of reduction of the parameter characterizing the working head load is not less than a first threshold within a preset time period.
  • the control module determines that the The load on the work head is reduced.
  • control module determines that the amount of decrease in the parameter characterizing the head load is less than a first threshold and greater than or equal to a second threshold.
  • the control module determines that the load of the working head is reduced. small.
  • the control module determines that the load of the working head is reduced.
  • At least one of a function of a second derivative, a function of a second derivative, a high order derivative or a high order derivative of the parameter characterizing the head load is a negative value and an absolute value thereof is not less than a fifth threshold
  • the control module determines that the load of the working head is reduced.
  • said parameter characterizing said head load is a current flowing through said motor.
  • control module intermittently outputs power to the working head by controlling a supply current of the power supply to the motor to output a pulse.
  • the power tool further includes an adjustment component operatively in different states and transmitting an adjustment signal corresponding to the state thereof, the control module adjusting the power source to the motor according to the adjustment signal The output current of the output pulse.
  • control module adjusts a supply current of a pulse output by the power source to the motor by adjusting at least one of a time width of a supply current of a single pulse or a time interval between supply currents of two adjacent pulses. .
  • the present invention also provides another power tool, the power tool comprising: a housing; a motor housed in the housing; a first working head and a second working head, the first work The head and the second working head are selectively driven by the motor; the detecting component detects a parameter characterizing the load of the power tool and outputs a detection signal; and the control module receives the detection signal and controls according to the detection signal The first working head and the second working head work; when the first working head is driven by the motor and the load of the power tool is reduced, the control module interrupts the torque output to the first working head .
  • the first working head is a screwdriver.
  • the second working head is a drill bit, and when the second working head is driven by the motor, and the load of the second working head is greater than or equal to a preset load value, the control module changes to the first The torque output of the two working heads.
  • the power tool further includes a triggering member and a sensing member, the triggering member is disposed on the first working head and/or the second working head, and the sensing member is disposed on the housing.
  • the sensing component sends an sensing signal to the control module, and the control module determines, according to the sensing signal, that the first working head or the second working is driven by the motor. head.
  • the present invention also provides a power tool control method, comprising the steps of: detecting a parameter characterizing a workload of a working head; outputting a detection signal according to the parameter characterizing the load of the working head; and receiving the detection signal And determining, when the load of the working head is reduced according to the detection signal, controlling the working head to intermittently output power.
  • the present invention also provides a power tool control method, the power tool driving the fastener embedded in the workpiece, comprising the steps of: detecting a parameter characterizing the load of the working head; determining, according to the parameter characterizing the load of the working head Whether the working head is separated from the fastener; when the judgment result is YES, the torque transmission to the working head is interrupted; the criterion for separating the working head from the fastener is that the load of the working head is reduced.
  • the power tool control method further includes the steps of: starting the motor; and shielding the receiving of the detection signal within a preset time after the motor is started.
  • the step of determining that the load of the working head is reduced according to the detection signal is specifically: when the amount of the parameter that characterizes the working head load is not less than a first threshold in a certain period of time, determining The load of the working head is reduced.
  • the specific step of determining the load reduction of the working head according to the detection signal is: when the amount of the parameter indicating the workload of the working head load is less than a first threshold and greater than or equal to a second threshold When appearing at least twice, the control module determines that the load of the working head is reduced.
  • determining that the amount of reduction of the parameter characterizing the workload of the working head is less than a first threshold and greater than A specific step of equal to or equal to the second threshold is to determine that the parameters characterizing the head load at at least three adjacent points in time are sequentially decreased.
  • the specific step of determining the load reduction of the working head according to the detection signal is: when the function of the first derivative or the first derivative of the parameter characterizing the working head load is a negative value and an absolute value thereof When not less than the second threshold, it is judged that the load of the working head is reduced.
  • the specific step of determining the load reduction of the working head according to the detection signal is: when the first derivative of the parameter characterizing the working head load is a negative value and the absolute value thereof is not less than a third threshold, And when the value of the parameter characterizing the head load is lower than the fourth threshold, it is determined that the load of the working head is reduced.
  • the specific step of determining the load reduction of the working head according to the detection signal is: when characterizing the second derivative of the parameter of the working head load, a function of the second derivative, a high order derivative, or a high When at least one of the functions of the order derivative is a negative value and the absolute value thereof is not less than the fifth threshold, it is judged that the load of the working head is decreased.
  • the parameter characterizing the head load is a current flowing through the motor.
  • the specific step of controlling the intermittent output power of the working head is to output a pulsed supply current to the motor.
  • control method further comprises the steps of: operatively adjusting the adjustment elements disposed on the power tool to be in different states; adjusting the width or adjacent of the supply current of the single pulse in response to the different states of the adjustment elements The time interval between the supply currents of the two pulses.
  • the power tool control method further includes the step of continuously outputting power when the power tool is restarted after the power tool is turned off.
  • the power tool control method further includes the step of continuously outputting power after the working head intermittently outputs the power preset time.
  • the present invention also provides another power tool control method, the power tool including a motor and a first working head and a second working head, the first working head and the second working head being alternatively Driven by the motor, the power tool control method includes the steps of: detecting a parameter characterizing a load of the power tool; confirming whether the first work head is driven by the motor; When the first working head is driven by the motor, it is confirmed whether the load of the power tool is reduced; when the load of the power tool is decreased, the motor is changed to drive the first working head.
  • the specific step of confirming whether the first working head is driven by the motor is: sensing a trigger member disposed on the first working head and/or the second working head through an inductive member disposed on the housing; receiving An inductive signal from the inductive element; confirming whether the first working head is driven by the motor based on the sensing signal.
  • the power tool and the control method thereof provided by the invention can automatically monitor whether a slip phenomenon occurs, and take corresponding measures when the slip phenomenon occurs to reduce the slip on the working head, the screw head, the surface of the workpiece, etc. Damage.
  • FIG. 1 is a schematic structural view of a power tool according to a preferred embodiment of the present invention.
  • FIG. 2 is a detailed block diagram of a first preferred embodiment of the control system of the first inventive concept.
  • Fig. 3 is a graph showing the current of the electric tool shown in Fig. 1 when the nut is loosely combined with the bolt, and the current supplied to the motor is changed with time.
  • Fig. 4 is a graph showing the relationship between the current supplied to the motor and the time when the nut is loosely coupled with the bolt when the power tool shown in Fig. 1 is loosened.
  • FIG. 5 is a detailed block diagram of a second preferred embodiment of the control system of the first inventive concept.
  • FIG. 6 is a detailed block diagram of a third preferred embodiment of the control system of the first inventive concept.
  • Fig. 7 is a flow chart showing a first preferred embodiment of the control method of the electric power tool according to the first inventive concept.
  • Fig. 8 is a flow chart showing a second preferred embodiment of the control method of the electric power tool according to the first inventive concept.
  • Fig. 9 is a flow chart showing a third preferred embodiment of the control method of the electric power tool according to the first inventive concept.
  • Figure 10 is a detailed block diagram of a first preferred embodiment of the control system of the second inventive concept.
  • FIG 11 is a detailed block diagram of a second preferred embodiment of the control system of the second inventive concept.
  • Figure 12 is a detailed block diagram of a third preferred embodiment of the control system of the second inventive concept.
  • Figure 13 is a flow chart showing a first preferred embodiment of the control method of the electric power tool according to the second inventive concept.
  • Figure 14 is a flow chart showing a second preferred embodiment of the control method of the power tool in the second inventive concept.
  • Fig. 15 is a flow chart showing a third preferred embodiment of the control method of the electric power tool according to the second invention concept.
  • Figure 16 is a detailed block diagram of a first preferred embodiment of the control system of the third inventive concept.
  • Figure 17 is a detailed block diagram of a second preferred embodiment of the control system of the third inventive concept.
  • FIG 18 is a detailed block diagram of a third preferred embodiment of the control system of the third inventive concept.
  • Fig. 19 is a flow chart showing a first preferred embodiment of the control method of the electric power tool according to the third invention concept.
  • Fig. 20 is a flow chart showing a second preferred embodiment of the control method of the electric power tool according to the third invention concept.
  • Figure 21 is a flow chart showing a third preferred embodiment of the control method of the electric power tool in the third inventive concept.
  • Fig. 22 is a block diagram showing the power tool of the first embodiment of the fifth invention concept.
  • FIG. 23 is a flowchart of a method of controlling a power tool according to a first embodiment of the fifth invention concept.
  • Control system 40 first control module, 46a
  • Preset module 41 second control module, 46b
  • control method and control system provided by the present invention can be applied to various types of power tools.
  • an electric impact wrench 10 includes a motor 12, a working head 14 and an output shaft 16 connected between the motor 12 and the working head 14; the working head 14 of the electric impact wrench 10 is in the motor 12 is driven to remove the nut 32 from the scaffolding 20, thereby loosening the nut 32 and the bolt 34 to facilitate disassembly of the scaffolding 20.
  • a control system 40 is also disposed within the electric impact wrench 10, and the control system 40 is located on the circuit board for controlling the rotational speed of the motor 12 when the electric impact wrench 10 performs the removal of the nut 32.
  • control system 40 includes a detection module 42 and a first control module 46a.
  • the detection module 42 is operative to detect a parameter x indicative of the load of the output shaft 16.
  • the nut 32 passes through the working head 14 to the output of the electric impact wrench 10 due to the presence of the thread fastening force between the nut 32 and the bolt 34.
  • the shaft 16 applies a resistive torque.
  • the working head 14 begins to tighten or remove the nut 32.
  • the resistance torque is proportional to the thread fastening force between the nut 32 and the bolt 34.
  • the thread fastening force between the nut 32 and the bolt 34 is also gradually increased, and the nut 32 and the bolt 34 are When fully tightened, the thread tightening force reaches a peak; conversely, during the removal of the nut 32 by the electric impact wrench 10, the thread tightening force is already at a peak, and the resistance of the output shaft 16 of the electric impact wrench 10 at the initial moment is The moment is the largest.
  • the motor 12 of the electric impact wrench 10 needs to output a large rotating torque to overcome the resistance torque at the peak, and the resistance of the output shaft 16 of the electric impact wrench 10 after the nut 32 and the bolt 34 are completely tightened. The moment is reduced to a gentle level, and the rotational torque output by the motor 12 is also simultaneously reduced to a gentle level.
  • the parameter x is used to indicate the load of the output shaft 16 of the electric impact wrench 10, that is, the resistance torque that the output shaft 16 of the electric impact wrench 10 is subjected to, and the resistance torque is consistent with the output torque of the motor 12 of the electric impact wrench 10,
  • the parameter related to the output torque of the motor 12 as the aforementioned parameter x
  • the magnitude of the load of the output shaft 16 can be identified by monitoring the parameter x.
  • the first control module 46a is configured to determine that the output shaft load is reduced to be equal to or less than a preset load according to the parameter x meeting a preset condition, thereby changing the rotation speed of the motor 12.
  • the first control module 46a includes a parameter determination sub-module 462a and a first motor shift sub-module 464a; the parameter determination sub-module 462a monitors the parameter x, determines whether the value of the parameter x meets a preset condition, and confirms the output shaft based on the foregoing judgment result. Whether the load on the 16 has been reduced to the preset load, and if so, the motor speed is changed by the first motor shift sub-module 464a. If not, the detecting module 42 reacquires the current parameter x, and the parameter determining sub-module 462a further determines whether the current parameter x is Meet the preset conditions.
  • FIG. 3 depicts a current curve of the current supplied to the motor 12 when the nut 32 is tightly coupled with the bolt 34, and the letter t indicates that the motor 12 starts to work.
  • the letter i represents the motor 12 provided to the electric impact wrench 10 Current value.
  • the curve in FIG. 3 includes a first portion A, a first inflection point H, a second portion B, a second inflection point I, a third portion C, a third inflection point J, a fourth portion D, a fifth portion E, and a sixth portion F.
  • the first part A is a rising curve, which indicates that the motor 12 has just started to start.
  • the nut 32 has not applied a resistance torque to the working head 14, and the first part A can be regarded as linear;
  • the first part A is the first The inflection point K and the subsequent second portion B, the first inflection point K has a downwardly inclined abrupt change with respect to the first portion A, and the second portion B is a descending curve, which indicates that the nut 32 has begun to abut against the working head 14, the nut 32 applies a resistance torque to the working head 14; after passing the second inflection point I, enters the third portion C of the basic level, at which time the working head 14 begins to overcome the resistance torque to slowly loosen the nut 32; as time passes, the third Part C undergoes a downward transition at the third inflection point J and forms a substantially descending fourth portion D, at which point the nut 32 is nearly completely released; then enters the fifth portion E, which is substantially a level
  • the straight line indicates that the
  • Fig. 4 depicts a graph of current supplied to the motor 12 over time when the electric impact wrench 10 is used to remove the loose nut 32 coupled with the bolt 34; wherein the letter t indicates that the motor 12 is operating. Time, the letter i represents the current value of the motor 12 supplied to the electric impact wrench 10.
  • the initial portion M is a rising curve indicating that the motor 12 has just started to start, at which time the nut 32 has not applied a resisting torque to the working head 14, and the initial portion M can be considered to be linear; following the subsequent intermediate portion of the initial portion F Part N, the middle portion N is a descending curve, which means that the nut 32 has begun to abut against the working head 14, and the nut 32 applies a resisting torque to the working head 14; since the nut 32 and the bolt 34 are not tightly coupled, the working head 14 is short.
  • the nut 32 and the bolt 34 are loosened at this time, and directly enter the substantially horizontal portion (not labeled), which is basically a horizontal straight line, indicating that the nut 32 has been completely loosened, and the motor 12 is in an idle state; Finally, the final part O is entered, at which time the motor 12 is turned off and the current i is also reduced to zero.
  • the parameter x is the current value of the motor 12 supplied to the electric impact wrench 10
  • the preset condition is that the current value of the motor 12 supplied to the electric impact wrench 10 is equal to or less than the preset power.
  • the preset current threshold in the preset condition is set to the current value I0 when the motor 12 is idling in the fifth part E of FIG. 3, which is also the final part of FIG.
  • the current value of the current supplied to the motor 12 can be obtained by collecting the current value multiple times and obtaining an average value, thereby reducing the current value error caused by the current fluctuation, which will not be described herein.
  • the preset current threshold is not limited to the current value I0 when the motor 12 is idling, or may be slightly larger or smaller than the no-load current value I0.
  • the nut 32 and the bolt 34 are also Nearly completely loosened, the resistance torque of the nut 32 to the output shaft 16 of the electric impact wrench 10 is also close to the resistance torque at the time of no-load, and the control precision of the electric impact wrench 10 can also be ensured.
  • the first motor shift sub-module 464a further includes a first time acquisition unit 4642a, a time determination unit 4644, and a motor control unit 4646.
  • the first time acquiring unit 4642a starts counting.
  • the first time acquiring unit 4642a generates the current time.
  • the target control unit 4464 outputs a preset time T1 as the target time T2, and the motor control unit 4646 selects a different mode of changing the motor rotation speed based on the target time T2 and the preset time T1.
  • the time determining unit 4464 outputs a corresponding control command to the motor control unit 4646, and the motor control unit 4646 passes the first preset. After the length of time, the motor 12 is turned off; thereby loosening the nut 32 and the bolt 34 sufficiently, but the two are not disengaged.
  • the first preset duration may be set according to the required stroke of the nut 32 from the current position to the complete disengagement of the bolt, so that at the end of the first preset duration, the nut 32 will still not be disengaged from the bolt 34 as a reference; preferably, the first The preset duration is 10 milliseconds.
  • the target time T2 is before the preset time T1
  • the time determining unit 4464 outputs another control command to the motor control unit 4646.
  • the motor control unit 4646 then shuts down the motor 12 immediately; thereby preventing the excess nut 32 and the bolt 34 from disengaging.
  • shutdown motor includes stopping and braking the motor, and will not be described here.
  • the nut 32 can be rotated out of the bolt 34 to the maximum extent, but not separated from the bolt 34, reducing manual operation by the user. The time taken to remove the nut 32 greatly increases the user experience.
  • the control system 40 is different from the first embodiment of the first concept of the present invention in that the control system 40 is only
  • the preset module 41 further includes an instruction preset sub-module 412, an instruction acquisition sub-module 414, and an instruction matching sub-module 416.
  • the command preset sub-module 412 is configured to preset a speed control demand instruction set, and includes a plurality of speed control demand instructions, and each speed control demand instruction corresponds to a specific manner of the step of changing the rotation speed of the motor;
  • the sub-module 414 is configured to obtain a user speed adjustment demand instruction;
  • the instruction matching sub-module 416 is configured to confirm the specific manner of the step of changing the motor speed according to the user speed adjustment demand instruction.
  • the first motor shift sub-module 464a changes the motor speed in accordance with the manner confirmed by the command matching sub-module 416.
  • different shift modes are set, for example, the long stroke is set to the first shift mode, and the medium and short strokes are set to the second shift mode; the user according to the different stroke of the nut
  • the best user speed control demand command is issued to obtain the most suitable mode for changing the motor speed; then, the shifting module changes the motor speed through the shift mode.
  • the user can select the way to change the motor speed according to the working condition, and improve the adaptability of the control system to different working conditions, thereby ensuring that the nut can always be removed to the optimal position under different working conditions.
  • the mode switching button is set on the electric impact wrench and the mode icon is marked on the circumference of the button, so that the user can operate the dial button to select the corresponding shift mode before use.
  • control system 40 is different from the first embodiment under the first concept in that the control system 40 further includes
  • the clock module 43 is configured to provide a time start point and control the detection module to start the detection parameter x at the time start.
  • the time starting point is a time node after the second preset time period after the power tool is turned on.
  • the foregoing time starting point may be T0 time, the current i at time T0 is located in the second part B in FIG. 3 and the middle part N in FIG. 4; before the T0 time, the control system does not start.
  • the control system starts to start and acquires the parameter x through its detection module. It can be understood by those skilled in the art that before the T0 time, the detection module detects the startup work, but the first control module does not start receiving the signal of the detection module or does not process the signal transmitted by the detection module.
  • the second preset duration may also be 0, and the aforementioned starting point of time is 0.
  • the second preset duration By setting the second preset duration, when the control system is started, the working head has been pressed against the nut, the nut has begun to apply a resisting torque to the working head, and the nut is about to be slowly released; so that the control system can detect it faster.
  • the parameter x meets the preset condition, it is avoided that in the first part A or the initial part M, the working head is not yet in contact with the nut, resulting in inefficient work and energy waste caused by the control system having no working demand.
  • the control system is different from the first embodiment only in that the parameter x is the output torque value of the motor, and the preset conditions include: the output torque of the motor The value is equal to or less than the preset torque threshold.
  • the detection motor output torque value can be obtained by the torque sensor; and the output torque of the motor at no load is used as the preset torque threshold.
  • control system is different from the first embodiment only in that the parameter x is the rotational speed value of the motor, and the preset condition includes: the rotational speed value of the motor is equal to Or greater than the preset speed threshold.
  • the detection motor speed value can be obtained by a speed detecting component such as a Hall element or a magnetic nail; and the speed of the motor at the time of no-load is used as a preset speed threshold.
  • the control system is different from the first embodiment only in that the parameter x is the acceleration value of the power tool, and the acceleration value is caused by the vibration of the power tool.
  • Preset conditions include: the acceleration of the output shaft is equal to or less than the preset acceleration Threshold
  • the detection of the output shaft acceleration value can be obtained by setting an acceleration sensor in the tool, and the rotation speed of the motor at the time of no-load is used as the preset speed threshold.
  • the control system is compared with the foregoing embodiment, and the corresponding parameter x and the preset condition in the control system can be used in the foregoing first to sixth embodiments.
  • the method mentioned in any one of the following; the difference is that when the target time T2 at which the parameter x meets the preset condition is after the preset time T1, the first motor shifting sub-module 464a is turned off after the motor is operated by the preset number of turns. Motor.
  • the control system is different from the seventh embodiment under the first concept only in that the target time T2 at which the parameter x meets the preset condition is After the preset time T1, the first motor shifting sub-module 464a turns off the motor after reducing the motor speed.
  • the control system is different from the seventh embodiment under the first concept only in that the target time T2 at which the parameter x meets the preset condition is After the preset time T1, the first motor shifting sub-module 464a reduces the motor speed, prompting the user by the speed reduction, causing the user to manually shut down the motor.
  • the control system is different from the seventh embodiment under the first concept only in that the target time T2 is satisfied regardless of the parameter x meeting the preset condition.
  • the first motor shifting sub-module 464a can prompt the user to cause the user to manually shut down the motor by periodically switching the motor between continuous forward and reverse rotations, either before or after the preset time T1.
  • the control system is different from the first embodiment of the first concept only in that the preset condition is that the motor is supplied to the electric impact wrench 10
  • the current value of 12 continues to be equal to or less than the preset current threshold for a third predetermined duration.
  • the preset current threshold is the current value I0 when the motor 12 is idling in the fifth part E of FIG. 3, and is also the current value I0 when the motor 12 is idling in the final part 0 of FIG.
  • the control system is different from the first embodiment under the first concept only in that the preset condition is that the control module determines the current
  • the value is decreased by less than or equal to the second preset threshold to be less than or equal to the first preset threshold.
  • the second preset threshold is greater than the first preset threshold.
  • the second preset threshold is a load value
  • the first preset threshold is a no-load value.
  • the control system can loosen the nut and the bolt without separating the nut and the bolt, and the user can manually separate the nut and the bolt according to the requirement, so that the user only needs to loosen the nut. Special working conditions.
  • control method of the power tool includes the following steps:
  • step S20 a parameter x indicating the load of the output shaft 16 is detected.
  • the nut 32 passes through the working head 14 to the output of the electric impact wrench 10 due to the presence of the thread fastening force between the nut 32 and the bolt 34.
  • the shaft 16 applies a resistive torque.
  • the working head 14 begins to tighten or remove the nut 32.
  • the resistance torque is proportional to the thread fastening force between the nut 32 and the bolt 34.
  • the thread fastening force between the nut 32 and the bolt 34 is also gradually increased, and the nut 32 and the bolt 34 are When fully tightened, the thread tightening force reaches a peak; conversely, during the removal of the nut 32 by the electric impact wrench 10, the thread tightening force is already at a peak, and the resistance of the output shaft 16 of the electric impact wrench 10 at the initial moment is The moment is the largest.
  • the motor 12 of the electric impact wrench 10 needs to output a large rotating torque to overcome the resistance torque at the peak, and the resistance of the output shaft 16 of the electric impact wrench 10 after the nut 32 and the bolt 34 are completely tightened. The moment is reduced to a gentle level, and the rotational torque output by the motor 12 is also simultaneously reduced to a gentle level.
  • the parameter x is used to indicate the load of the output shaft 16 of the electric impact wrench 10, that is, the resistance torque that the output shaft 16 of the electric impact wrench 10 is subjected to, and the resistance torque is consistent with the output torque of the motor 12 of the electric impact wrench 10,
  • the parameter related to the output torque of the motor 12 as the aforementioned parameter x
  • the magnitude of the load of the output shaft 16 can be identified by monitoring the parameter x.
  • step S40 determining that the output shaft load is reduced to be equal to or less than a preset load according to the parameter x meeting the preset condition, thereby changing the rotation speed of the motor.
  • the step S40 specifically includes:
  • step S42 monitoring parameter x, determining whether the value of the parameter x meets a preset condition, based on the foregoing judgment knot To confirm whether the load on the output shaft 16 has been reduced to the preset load, and if so, execute step S44;
  • FIG. 3 depicts a current curve of the current supplied to the motor 12 when the nut 32 is tightly coupled with the bolt 34, and the letter t indicates that the motor 12 starts to work. At the time, the letter i indicates the current value of the motor 12 supplied to the electric impact wrench 10.
  • the curve in FIG. 3 includes a first portion A, a first inflection point H, a second portion B, a second inflection point I, a third portion C, a third inflection point J, a fourth portion D, a fifth portion E, and a sixth portion F.
  • the first part A is a rising curve, which indicates that the motor 12 has just started to start.
  • the nut 32 has not applied a resistance torque to the working head 14, and the first part A can be regarded as linear;
  • the first part A is the first The inflection point K and the subsequent second portion B, the first inflection point K has a downwardly inclined abrupt change with respect to the first portion A, and the second portion B is a descending curve, which indicates that the nut 32 has begun to abut against the working head 14, the nut 32 applies a resistance torque to the working head 14; after passing the second inflection point I, enters the third portion C of the basic level, at which time the working head 14 begins to overcome the resistance torque to slowly loosen the nut 32; as time passes, the third Part C undergoes a downward transition at the third inflection point J and forms a substantially descending fourth portion D, at which point the nut 32 is nearly completely released; then enters the fifth portion E, which is substantially a level
  • the straight line indicates that the
  • Fig. 4 depicts a graph of current supplied to the motor 12 over time when the electric impact wrench 10 is used to remove the loose nut 32 coupled with the bolt 34; wherein the letter t indicates that the motor 12 is operating. Time, the letter i represents the current value of the motor 12 supplied to the electric impact wrench 10.
  • the initial portion M is a rising curve indicating that the motor 12 has just started to start, at which time the nut 32 has not applied a resisting torque to the working head 14, and the initial portion M can be considered to be linear; following the subsequent intermediate portion of the initial portion F Part N, the middle portion N is a descending curve, which means that the nut 32 has begun to abut against the working head 14, and the nut 32 applies a resisting torque to the working head 14; since the nut 32 and the bolt 34 are not tightly coupled, the working head 14 is short.
  • the part is basically a horizontal straight line, indicating that the nut 32 has been completely loosened, the motor 12 is in an idle state; finally enters the final part O, this When the motor 12 is turned off, the current i is also reduced to zero.
  • the parameter x is the current value of the motor 12 supplied to the electric impact wrench 10
  • the preset condition is that the current value of the motor 12 supplied to the electric impact wrench 10 is equal to or smaller than Preset current threshold.
  • the preset current threshold in the preset condition is set to the current value I0 when the motor 12 is idling in the fifth part E of FIG. 3, which is also the final part of FIG.
  • the current value I0 when the motor 12 is idling when the current value as the parameter x falls to the current value I0 when the motor 12 is idling, it indicates that the nut 32 has been loosened with the bolt 34, thereby changing the rotational speed of the motor 12.
  • the current value of the current supplied to the motor 12 can be obtained by collecting the current value multiple times and obtaining an average value, thereby reducing the current value error caused by the current fluctuation, which will not be described herein.
  • the preset current threshold is not limited to the current value I0 when the motor 12 is idling, or may be slightly larger or smaller than the no-load current value I0.
  • the nut 32 and the bolt 34 are also Nearly completely loosened, the resistance torque of the nut 32 to the output shaft 16 of the electric impact wrench 10 is also close to the resistance torque at the time of no-load, and the control precision of the electric impact wrench 10 can also be ensured.
  • the target time T2 is after the preset time T1, after the first preset time period is passed through S446, the motor 12 is turned off; thereby fully loosening the nut 32 and the bolt 34. But the two will not leave.
  • the first preset duration may be set according to the required stroke of the nut 32 from the current position to the complete disengagement of the bolt, so that at the end of the first preset duration, the nut 32 will still not be disengaged from the bolt 34 as a reference; preferably, the first The preset duration is 10 milliseconds.
  • the target time T2 is immediately turned off by the S448 before the preset time T1; thereby preventing the nut 32 and the bolt 34 from being disengaged.
  • shutdown motor includes two steps of stopping and braking the motor, and will not be described here.
  • the nut 32 can be rotated out of the bolt 34 to the maximum extent, but not separated from the bolt 34, reducing manual operation by the user. The time taken to remove the nut 32 greatly increases the user experience.
  • control method is different from the other embodiments of the present invention only in that the control method further includes the step before step S20.
  • S10 which specifically includes:
  • a preset speed regulation demand instruction set which includes a plurality of speed regulation demand instructions, and each speed adjustment demand instruction corresponds to a specific manner of the step of changing the rotation speed of the motor;
  • step S80 changes the motor speed through the shift mode.
  • the user can select the way to change the motor speed according to the working condition, and improve the adaptability of the control method to different working conditions, thereby ensuring that the nut can always be removed to the optimal position under different working conditions.
  • the mode switching button is set on the electric impact wrench and the mode icon is marked on the circumference of the button, so that the user can operate the dial button to select the corresponding shift mode before use.
  • control The method of the method is different from the first embodiment of the control method provided by the first concept of the present invention.
  • the method further includes the step S30, the step S30 specifically includes: providing a time start point, and step S20 starts at the time start point. .
  • the time starting point is a time node after the second preset time period after the power tool is turned on.
  • the foregoing time starting point may be T0 time, the current i at time T0 is located in the second part B in FIG. 3 and the middle part N in FIG. 4; before the T0 time, the control method does not start.
  • the start of step S20 is started.
  • the second preset duration may also be 0, and the aforementioned starting point of time is 0.
  • the control method when the control method is started, the working head has been pressed against the nut, the nut has begun to apply a resistance torque to the working head, and the nut is about to be slowly released; so that the control method can detect more quickly.
  • the parameter x meets the preset condition, it is avoided that in the first part A or the initial part M, the working head is not yet in contact with the nut, resulting in inefficient work and energy waste caused by the control method having no working demand.
  • the control method is different from the first embodiment of the first concept of the present invention in that the parameter x is the output torque value of the motor,
  • the condition includes that the output torque value of the motor is equal to or less than a preset torque threshold.
  • the detection motor output torque value can be obtained by the torque sensor; and the output torque of the motor at no load is used as the preset torque threshold.
  • the control method is different from the first embodiment of the first concept of the present invention in that the parameter x is the rotational speed value of the motor, and the preset Conditions include: the motor speed value is equal to or greater than the preset speed threshold.
  • the detection motor speed value can be obtained by a speed detecting component such as a Hall element or a magnetic nail; and the speed of the motor at the time of no-load is used as a preset speed threshold.
  • the control method is different from the first embodiment of the first concept of the present invention in that the parameter x is an acceleration value of the power tool, The acceleration value is caused by the vibration of the power tool.
  • the preset conditions include: the acceleration of the output shaft is equal to or less than the preset acceleration threshold.
  • Detecting the output shaft acceleration value can be obtained by the built-in acceleration sensor in the tool.
  • the speed of the motor is used as the preset speed threshold.
  • the control method is different from the foregoing embodiment only in that the parameter x and the preset condition corresponding to the control method can adopt the first aspect of the present invention.
  • the method mentioned in any one of the foregoing first to sixth embodiments is different in that, when the target time T2 at which the parameter x meets the preset condition is after the preset time T1, the step S446 is adjusted to: Shut down the motor after the motor has been running for a preset number of turns.
  • the control method is different from the seventh embodiment of the first concept of the present invention in that the parameter x is in accordance with the preset condition.
  • the step S446 is adjusted to: turn off the motor after reducing the motor speed.
  • the control method is different from the seventh embodiment of the first concept of the present invention in that the parameter x is in accordance with the preset condition.
  • the step S446 is adjusted to: reduce the motor speed. The user is prompted by the speed reduction to cause the user to manually shut down the motor.
  • the control method is different from the seventh embodiment of the first concept of the present invention in that the parameter x is in accordance with the preset condition.
  • steps S446 and S448 can be adjusted to: the motor periodically switches between continuous forward and reverse. By prompting the user in this way, the user manually shuts down the motor.
  • the control method is different from the first embodiment of the first concept in that the preset condition is that the motor is supplied to the electric impact wrench 10
  • the current value of 12 continues to be equal to or less than the preset current threshold for a third predetermined duration.
  • the preset current threshold is the current value I0 when the motor 12 is idling in the fifth part E of FIG. 3, and is also the current value I0 when the motor 12 is idling in the final part 0 of FIG.
  • the control method is different from the first embodiment in the first concept in that the preset condition is that the control module determines that the current value is greater than Or equal to the second preset threshold, reduced to less than or equal to the first preset threshold.
  • the second preset threshold is greater than the first preset threshold.
  • the second preset threshold is a load value
  • the first preset threshold is a no-load value.
  • control system 40 includes a detection module 42, a second calculation module 44a, and a second control module 46b.
  • the detection module 42 is operative to detect a parameter x indicative of the load of the output shaft 16.
  • the nut 32 passes through the working head 14 to the output of the electric impact wrench 10 due to the presence of the thread fastening force between the nut 32 and the bolt 34.
  • the shaft 16 applies a resistive torque.
  • the working head 14 begins to tighten or remove the nut 32.
  • the resistance torque is proportional to the thread fastening force between the nut 32 and the bolt 34.
  • the thread fastening force between the nut 32 and the bolt 34 is also gradually increased, and the nut 32 and the bolt 34 are When fully tightened, the thread tightening force reaches a peak; conversely, during the removal of the nut 32 by the electric impact wrench 10, the thread tightening force is already at a peak, and the resistance of the output shaft 16 of the electric impact wrench 10 at the initial moment is The moment is the largest.
  • the motor 12 of the electric impact wrench 10 needs to output a large rotating torque to overcome the resistance torque at the peak, and the resistance of the output shaft 16 of the electric impact wrench 10 after the nut 32 and the bolt 34 are completely tightened. The moment is reduced to a gentle level, and the rotational torque output by the motor 12 is also simultaneously reduced to a gentle level.
  • the parameter x is used to indicate the load of the output shaft 16 of the electric impact wrench 10, that is, the resistance torque that the output shaft 16 of the electric impact wrench 10 is subjected to, and the resistance torque is consistent with the output torque of the motor 12 of the electric impact wrench 10,
  • the parameter related to the output torque of the motor 12 as the aforementioned parameter x
  • the magnitude of the load of the output shaft 16 can be identified by monitoring the parameter x.
  • the second calculation module 44a calculates a preset function f(x) of the parameter x.
  • the preset function f(x) is the first derivative of the parameter x.
  • the second control module 46b includes a function determining sub-module 462b and a second motor shifting sub-module 464b; the function determining sub-module 462b monitors the parameter x, and determines whether the preset function f(x) of the parameter x meets a preset condition, based on the foregoing The result of the determination is to confirm whether the load on the output shaft 16 has decreased to be equal to or less than the preset load. If so, the motor speed is changed by the second motor shift sub-module 464b.
  • the detecting module 42 reacquires the current parameter x, and then the second The calculation module 44a calculates the current preset function f(x), and the function determination sub-module 462b further determines whether the current preset function f(x) conforms to the preset. condition.
  • FIG. 3 depicts a current curve of the current supplied to the motor 12 when the nut 32 is tightly coupled with the bolt 34, and the letter t indicates that the motor 12 starts to work. At the time, the letter i indicates the current value of the motor 12 supplied to the electric impact wrench 10.
  • the curve in FIG. 3 includes a first portion A, a first inflection point H, a second portion B, a second inflection point I, a third portion C, a third inflection point J, a fourth portion D, a fifth portion E, and a sixth portion F.
  • the first part A is a rising curve, which indicates that the motor 12 has just started to start.
  • the nut 32 has not applied a resistance torque to the working head 14, and the first part A can be regarded as linear;
  • the first part A is the first The inflection point K and the subsequent second portion B, the first inflection point K has a downwardly inclined abrupt change with respect to the first portion A, and the second portion B is a descending curve, which indicates that the nut 32 has begun to abut against the working head 14, the nut 32 applies a resistance torque to the working head 14; after passing the second inflection point I, enters the third portion C of the basic level, at which time the working head 14 begins to overcome the resistance torque to slowly loosen the nut 32; as time passes, the third Part C undergoes a downward transition at the third inflection point J and forms a substantially descending fourth portion D, at which point the nut 32 is nearly completely released; then enters the fifth portion E, which is substantially a level
  • the straight line indicates that the
  • Fig. 4 depicts a graph of current supplied to the motor 12 over time when the electric impact wrench 10 is used to remove the loose nut 32 coupled with the bolt 34; wherein the letter t indicates that the motor 12 is operating. Time, the letter i represents the current value of the motor 12 supplied to the electric impact wrench 10.
  • the initial portion M is a rising curve indicating that the motor 12 has just started to start, at which time the nut 32 has not applied a resisting torque to the working head 14, and the initial portion M can be considered to be linear; following the subsequent intermediate portion of the initial portion F Part N, the middle portion N is a descending curve, which means that the nut 32 has begun to abut against the working head 14, and the nut 32 applies a resisting torque to the working head 14; since the nut 32 and the bolt 34 are not tightly coupled, the working head 14 is short.
  • the nut 32 and the bolt 34 are loosened inside, and directly enter the basic horizontal portion (not labeled), which is basically a section of water.
  • a flat straight line indicates that the nut 32 has been completely released and the motor 12 is in an unloaded state; finally, the final portion O is entered, at which time the motor 12 is shut down and the current i is also reduced to zero.
  • the parameter x is the current value of the motor 12 supplied to the electric impact wrench 10
  • the preset function f(x) is the first derivative value of the parameter x, and the aforementioned preset condition Then, the first derivative of the current value of the motor 12 supplied to the electric impact wrench 10 is equal to or smaller than the preset derivative threshold.
  • the current i will generate noise, and the current i will appear as an irregular curve or burr on the relationship of time t, thereby affecting the calculation of the first derivative value.
  • the following steps may be included in the calculation of the first derivative value, and the current may be measured at a plurality of consecutive time intervals, the current values of which are i1, i2, i3, ... in, respectively.
  • the first derivatives di1/dt1, di2/dt2, di3/dt3, ... din/dtn are obtained for the measured currents i1, i2, i3, ..., respectively, and the obtained n di/dt are obtained.
  • the average is then judged whether the value of the average is consistent with a threshold equal to or less than the preset derivative.
  • the preset derivative threshold in the preset condition is set as the first derivative value of the current value in the preset position in the fourth portion D in FIG. 3, which is also the middle portion in FIG.
  • the first derivative value of the current value smaller than the preset position in the fourth portion D of FIG. 3 or the intermediate portion N in FIG. 4 indicates that the current drops sharply, the nut 32 has been loosened with the bolt 34, and the second motor shift submodule 464b The rotational speed of the motor 12 is then varied.
  • the second motor shifting sub-module 464b includes a second timing acquisition unit 4642b, a timing determination unit 4464, and a motor control unit 4646.
  • the second time acquiring unit 4642b starts counting.
  • the second time acquiring unit 4642b Generate the current moment as the target time T2
  • the output to the time determination unit 4644 stores the preset time T1.
  • the motor control unit 4646 selects different ways of changing the motor rotation speed according to the target time T2 and before and after the preset time T1.
  • the time determining unit 4464 outputs a corresponding control command to the motor control unit 4646, and the motor control unit 4646 passes the first preset. After the length of time, the motor 12 is turned off; thereby loosening the nut 32 and the bolt 34 sufficiently, but the two are not disengaged.
  • the first preset duration may be set according to the required stroke of the nut 32 from the current position to the complete disengagement of the bolt, so that at the end of the first preset duration, the nut 32 will still not be disengaged from the bolt 34 as a reference; preferably, the first The preset duration is 10 milliseconds.
  • the target timing T2 is before the preset time T1
  • the timing determining unit 4464 outputs another control command to the motor control unit 4646, and the motor control unit 4646 immediately shuts down the motor. 12; thereby preventing the nut 32 and the bolt 34 from being disengaged.
  • shutdown motor includes stopping and braking the motor, and will not be described here.
  • the nut 32 can be rotated out of the bolt 34 to the maximum extent, but not separated from the bolt 34, reducing manual operation by the user. The time taken to remove the nut 32 greatly increases the user experience.
  • control system 40 is different from the first embodiment of the second inventive concept of the present invention, except that the control system 40 further includes
  • the preset module 41 includes an instruction preset sub-module 412, an instruction acquisition sub-module 414, and an instruction matching sub-module 416.
  • the command preset sub-module 412 is configured to preset a speed control demand instruction set, and includes a plurality of speed control demand instructions, and each speed control demand instruction corresponds to a specific manner of the step of changing the speed of the motor;
  • the acquisition sub-module 414 is configured to obtain a user speed adjustment demand instruction;
  • the instruction matching sub-module 416 is configured to confirm the specific manner of the step of changing the rotation speed of the motor according to the user speed adjustment demand instruction.
  • the second motor shifting sub-module 464b changes the motor speed in accordance with the manner confirmed by the command matching sub-module 416.
  • different shift modes are set, for example, the long stroke is set to the first shift mode, and the medium and short strokes are set to the second shift mode; the user according to the different stroke of the nut
  • the best user speed control demand command is issued to obtain the most suitable mode for changing the motor speed; then, the shifting module changes the motor speed through the shift mode.
  • the user can select the way to change the motor speed according to the working condition, and improve the adaptability of the control system to different working conditions, thereby ensuring that the nut can always be removed to the optimal position under different working conditions.
  • the mode switching button is set on the electric impact wrench and the mode icon is marked on the circumference of the button, so that the user can operate the dial button to select the corresponding shift mode before use.
  • control system 40 differs from the first embodiment of the second inventive concept of the present invention in that the control system 40 further includes a clock module. 43.
  • the clock module 43 is configured to provide a time start point and control the detection module to start the detection parameter x at the time start.
  • the time starting point is a time node after the second preset time period after the power tool is turned on.
  • the foregoing time starting point may be T0 time, the current i at time T0 is located in the second part B in FIG. 3 and the middle part N in FIG. 4; before the T0 time, the control system does not start.
  • the control system starts to start and acquires the parameter x through its detection module.
  • the second preset duration may also be 0, and the aforementioned starting point of time is 0.
  • the control system By setting the second preset duration, when the control system is started, the working head has been pressed against the nut, the nut has begun to apply a resisting torque to the working head, and the nut is about to be slowly released; so that the control system can detect it faster.
  • the preset function f(x) meets the preset condition, it is avoided that in the first part A or the initial part M, the working head is not yet in contact with the nut, resulting in the work efficiency and energy caused by the control system having no working demand. waste.
  • the control system is compared with the first embodiment of the second inventive concept of the present invention; the only difference is that the preset function f(x) is the parameter x
  • the preset condition is: the preset function f(x) is also equal to or smaller than the preset derivative threshold.
  • the preset function f(x) can also be a multi-order derivative of the parameter x, and will not be described here.
  • control system is different from the first embodiment of the second inventive concept of the present invention in that the parameter x is the output torque value of the motor 12;
  • the condition is that the first derivative of the output torque is equal to or less than the preset torque derivative threshold.
  • the motor output torque value can be obtained by the torque sensor; the method for obtaining the preset torque derivative threshold can refer to the foregoing method for obtaining the preset current derivative, and by constructing the torque curve of the motor, the first derivative value of the torque when the motor is not loaded is clarified. It is used as the preset torque derivative threshold, and will not be described here.
  • the control system is compared with the foregoing embodiment of the second inventive concept of the present invention, the corresponding parameter x and the preset condition in the control system can adopt the present invention.
  • the mode mentioned in any one of the foregoing first to fifth embodiments under the second inventive concept, the difference is that the target time T2 at which the preset function f(x) meets the preset condition is at the preset time T1 Thereafter, the second motor shifting sub-module 464b shuts down the motor after the motor has been operated for a predetermined number of turns.
  • control system is different from the sixth embodiment of the second inventive concept of the present invention only in that the preset function f(x) meets the preset condition.
  • the target time T2 is at a preset time T1
  • the second motor shifting sub-module 464b lowers the motor speed and then shuts down the motor.
  • the control system is different from the sixth embodiment of the second inventive concept of the present invention only in that the preset function f(x) meets the preset condition.
  • the target time T2 is at a preset time T1
  • the second motor shifting sub-module 464b lowers the motor speed, prompting the user by the speed reduction, so that the user manually shuts down the motor.
  • the control system is different from the sixth embodiment of the second inventive concept of the present invention only in that the preset function f(x) conforms to the preset condition.
  • the second motor shifting sub-module 464b can prompt the user to make the user manually shut down by periodically switching the motor between continuous forward and reverse rotations. Motor.
  • the control system can loosen the nut and the bolt without separating the nut and the bolt, and the user can manually separate the nut and the bolt according to the requirement, and the utility model can be used. The user only needs to loosen the special working condition of the nut.
  • control method of the power tool includes the following steps:
  • step S20 a parameter x indicating the load of the output shaft 16 is detected.
  • the nut 32 passes through the working head 14 to the output of the electric impact wrench 10 due to the presence of the thread fastening force between the nut 32 and the bolt 34.
  • the shaft 16 applies a resistive torque.
  • the working head 14 begins to tighten or remove the nut 32.
  • the resistance torque is proportional to the thread fastening force between the nut 32 and the bolt 34.
  • the thread fastening force between the nut 32 and the bolt 34 is also gradually increased, and the nut 32 and the bolt 34 are When fully tightened, the thread tightening force reaches a peak; conversely, during the removal of the nut 32 by the electric impact wrench 10, the thread tightening force is already at a peak, and the resistance of the output shaft 16 of the electric impact wrench 10 at the initial moment is The moment is the largest.
  • the motor 12 of the electric impact wrench 10 needs to output a large rotating torque to overcome the resistance torque at the peak, and the resistance of the output shaft 16 of the electric impact wrench 10 after the nut 32 and the bolt 34 are completely tightened. The moment is reduced to a gentle level, and the rotational torque output by the motor 12 is also simultaneously reduced to a gentle level.
  • the parameter x is used to indicate the load of the output shaft 16 of the electric impact wrench 10, that is, the resistance torque that the output shaft 16 of the electric impact wrench 10 is subjected to, and the resistance torque is consistent with the output torque of the motor 12 of the electric impact wrench 10,
  • the parameter related to the output torque of the motor 12 as the aforementioned parameter x
  • the magnitude of the load of the output shaft 16 can be identified by monitoring the parameter x.
  • step S40 the preset function f(x) of the parameter x is calculated.
  • step S60 which specifically includes:
  • step S62 Determine whether the preset function f(x) of the parameter x meets the preset condition, and confirm whether the load on the output shaft 16 has decreased to be equal to or less than the preset load based on the foregoing determination result, and if yes, execute step S64; if not, Returning to step S20;
  • FIG. 3 depicts a current curve of the current supplied to the motor 12 when the nut 32 is tightly coupled to the bolt 34 by the electric impact wrench 10; Indicates the time at which the motor 12 starts operating, and the letter i indicates the current value of the motor 12 supplied to the electric impact wrench 10.
  • the curve in FIG. 3 includes a first portion A, a first inflection point H, a second portion B, a second inflection point I, a third portion C, a third inflection point J, a fourth portion D, a fifth portion E, and a sixth portion F.
  • the first part A is a rising curve, which indicates that the motor 12 has just started to start.
  • the nut 32 has not applied a resistance torque to the working head 14, and the first part A can be regarded as linear;
  • the first part A is the first The inflection point K and the subsequent second portion B, the first inflection point K has a downwardly inclined abrupt change with respect to the first portion A, and the second portion B is a descending curve, which indicates that the nut 32 has begun to abut against the working head 14, the nut 32 applies a resistance torque to the working head 14; after passing the second inflection point I, enters the third portion C of the basic level, at which time the working head 14 begins to overcome the resistance torque to slowly loosen the nut 32; as time passes, the third Part C undergoes a downward transition at the third inflection point J and forms a substantially descending fourth portion D, at which point the nut 32 is nearly completely released; then enters the fifth portion E, which is substantially a level
  • the straight line indicates that the
  • Fig. 4 depicts a graph of current supplied to the motor 12 over time when the electric impact wrench 10 is used to remove the loose nut 32 coupled with the bolt 34; wherein the letter t indicates that the motor 12 is operating. Time, the letter i represents the current value of the motor 12 supplied to the electric impact wrench 10.
  • the initial portion M is a rising curve indicating that the motor 12 has just started to start, at which time the nut 32 has not applied a resisting torque to the working head 14, and the initial portion M can be considered to be linear; following the subsequent intermediate portion of the initial portion F Part N, the middle portion N is a descending curve, which means that the nut 32 has begun to abut against the working head 14, and the nut 32 applies a resisting torque to the working head 14; since the nut 32 and the bolt 34 are not tightly coupled, the working head 14 is short.
  • the nut 32 and the bolt 34 are loosened at this time, and directly enter the substantially horizontal portion (not labeled), which is basically a horizontal straight line, indicating that the nut 32 has been completely loosened, and the motor 12 is in an idle state; Finally, the final part O is entered, at which time the motor 12 is turned off and the current i is also reduced to zero.
  • the parameter x is an electric impact wrench
  • the current value of the motor 12 in the 10th, the preset function f(x) is the first derivative value of the parameter x, and the preset condition is: the first derivative value of the current value of the motor 12 supplied to the electric impact wrench 10 is equal to or smaller than Preset derivative threshold.
  • the current i will generate noise, and the current i will appear as an irregular curve or burr on the relationship of time t, thereby affecting the calculation of the first derivative value.
  • the following steps may be included in the calculation of the first derivative value, and the current may be measured at a plurality of consecutive time intervals, the current values of which are i1, i2, i3, ... in, respectively.
  • the first derivatives di1/dt1, di2/dt2, di3/dt3, ... din/dtn are obtained for the measured currents i1, i2, i3, ..., respectively, and the obtained n di/dt are obtained.
  • the average is then judged whether the value of the average is consistent with a threshold less than the preset derivative.
  • the preset current in the preset condition is set as the first derivative value of the current value in the preset position in the fourth portion D in FIG. 3, which is also the middle portion N in FIG.
  • the first derivative value of the current value in the preset position obviously, the fourth portion D is steeper than the waveform in the second portion B, so that the preset position can be accurately recognized, and the preset function f(x) is reduced to be equal to or smaller than
  • the first derivative value of the current value in the fourth portion D in FIG. 3 or in the intermediate portion N in FIG. 4 indicates that the current drops sharply, the nut 32 has been loosened with the bolt 34, and the motor 12 is changed by step S64. Rotating speed.
  • the target time T2 is after the preset time T1, after the first preset time period is passed through S646, the motor 12 is turned off; thereby fully loosening the nut 32 and the bolt 34. But the two will not leave.
  • the first preset duration may be set according to the required stroke of the nut 32 from the current position to the complete disengagement of the bolt, so that at the end of the first preset duration, the nut 32 will still not be disengaged from the bolt 34 as a reference; preferably, the first The preset duration is 10 milliseconds.
  • the target time T2 is immediately turned off by the S648 before the preset time T1; thereby preventing the nut 32 and the bolt 34 from being disengaged.
  • shutdown motor includes two steps of stopping and braking the motor, and will not be described here.
  • the nut 32 can be rotated out of the bolt 34 to the maximum extent, but not separated from the bolt 34, reducing manual operation by the user. The time taken to remove the nut 32 greatly increases the user experience.
  • control method is different from the other embodiments in that the control method further includes the step S10 before the step S20, which specifically includes:
  • the preset speed regulation demand instruction set includes a plurality of speed regulation demand instructions, and each speed adjustment demand instruction corresponds to a specific manner of the step of changing the speed of the motor;
  • step S80 changes the motor speed through the shift mode.
  • the user can select the way to change the motor speed according to the working condition, and improve the control method.
  • the adaptability of different working conditions ensures that the nut can always be removed to the optimal position under different working conditions.
  • the mode switching button is set on the electric impact wrench and the mode icon is marked on the circumference of the button, so that the user can operate the dial button to select the corresponding shift mode before use.
  • control method is different from the first embodiment of the second inventive concept of the present invention in that the control method further includes step S30, Step S30 specifically includes: providing a time start point, and step S20 is started at the time start point.
  • the time starting point is a time node after the second preset time period after the power tool is turned on.
  • the foregoing time starting point may be T0 time, the current i at time T0 is located in the second part B in FIG. 3 and the middle part N in FIG. 4; before the T0 time, the control method does not start.
  • the start of step S20 is started.
  • the second preset duration may also be 0, and the aforementioned starting point of time is 0.
  • the control method By setting the second preset duration, when the control method is started, the working head has been pressed against the nut, the nut has begun to apply a resistance torque to the working head, and the nut is about to be slowly released; so that the control method can detect more quickly.
  • the preset function f(x) meets the preset condition, it is avoided that in the first part A or the initial part M, the working head is not yet in contact with the nut, resulting in the work efficiency and energy caused by the control method having no working demand. waste.
  • the control method is compared with the first embodiment of the second inventive concept of the present invention; the only difference is that the preset function f(x) is the parameter x
  • the preset condition is: the preset function f(x) is also equal to or smaller than the preset derivative threshold.
  • the preset function f(x) can also be a multi-order derivative of the parameter x, and will not be described here.
  • control method is different from the first embodiment of the second inventive concept of the present invention, except that the parameter x is the output torque value of the motor 12;
  • the condition is that the first derivative of the output torque is equal to or less than the preset torque derivative threshold.
  • the motor output torque value can be obtained by the torque sensor; the method for obtaining the preset torque derivative threshold can refer to the foregoing method for obtaining the preset current derivative, and by constructing the torque curve of the motor, the first derivative value of the torque when the motor is not loaded is clarified. It is used as the preset torque derivative threshold, and will not be described here.
  • control method and the second aspect of the present invention may adopt the method mentioned in any one of the foregoing first to fifth embodiments of the second inventive concept of the present invention, as compared with the foregoing embodiment under the concept of the present invention.
  • the difference is that when the target time T2 at which the preset function f(x) meets the preset condition is after the preset time T1, the step S646 is adjusted to: shut down the motor after the motor runs the preset number of turns.
  • control method is different from the sixth embodiment of the second inventive concept of the present invention only in that the preset function f(x) meets the preset condition.
  • step S646 is adjusted to: turn off the motor after reducing the motor speed.
  • step S646 is adjusted to: reduce the motor speed, prompt the user by the speed reduction, so that the user manually shuts down the motor.
  • the control method is different from the sixth embodiment of the second inventive concept of the present invention in that the preset function f(x) meets the preset condition.
  • steps S646 and S648 can be adjusted to periodically switch between the continuous forward and reverse rotations of the motor. To prompt the user to manually shut down the motor.
  • control system 40 includes a detection module 42, a third calculation module 44c, and a control module 46.
  • the detection module 42 is operative to detect a parameter x indicative of the load of the output shaft 16.
  • the nut 32 passes through the working head 14 to the output of the electric impact wrench 10 due to the presence of the thread fastening force between the nut 32 and the bolt 34.
  • the shaft 16 applies a resistive torque.
  • the working head 14 begins to tighten or remove the nut 32.
  • the resistance torque is proportional to the thread fastening force between the nut 32 and the bolt 34.
  • the thread fastening force between the nut 32 and the bolt 34 is also gradually increased, and the nut 32 and the bolt 34 are When fully tightened, the thread tightening force reaches a peak; on the contrary, during the process of removing the nut 32 from the electric impact wrench 10, the thread tightening force is already at the peak, the initial moment, the electric impact wrench
  • the output shaft 16 of 10 is subjected to the maximum resistance torque.
  • the motor 12 of the electric impact wrench 10 needs to output a large rotating torque to overcome the resistance torque at the peak.
  • the electric impact wrench The resistance torque of the output shaft 16 of 10 is reduced to a gentle level, and the rotational torque output by the motor 12 is also reduced to a gentle level.
  • the parameter x is used to indicate the load of the output shaft 16 of the electric impact wrench 10, that is, the resistance torque that the output shaft 16 of the electric impact wrench 10 is subjected to, and the resistance torque is consistent with the output torque of the motor 12 of the electric impact wrench 10,
  • the parameter related to the output torque of the motor 12 as the aforementioned parameter x
  • the magnitude of the load of the output shaft 16 can be identified by monitoring the parameter x.
  • the third calculation module 44c calculates a preset function f(x) of the parameter x, which is the first derivative of the parameter x.
  • the control module 46 determines that the output shaft load is reduced to be equal to or less than a preset load according to the parameter x and its preset function f(x) according to a preset condition, thereby changing the rotational speed of the motor.
  • the control module 46 includes a parameter function determining sub-module 462c and a third motor shifting sub-module 464c.
  • the parameter determination sub-module 462c monitors the parameter x, determines whether the parameter x and its preset function f(x) meet the preset condition, and determines that the load on the output shaft 16 has been reduced to the preset load when both are met, and if so, The motor speed is changed by the third motor shift sub-module 464c. If not, the detecting module 42 reacquires the current parameter x, and the third calculating module 44c calculates the current preset function f(x), and the parameter determining sub-module 462c further determines Whether the current preset function f(x) meets the preset condition.
  • FIG. 3 depicts a current curve of the current supplied to the motor 12 when the nut 32 is tightly coupled with the bolt 34, and the letter t indicates that the motor 12 starts to work. At the time, the letter i indicates the current value of the motor 12 supplied to the electric impact wrench 10.
  • the curve in FIG. 3 includes a first portion A, a first inflection point H, a second portion B, a second inflection point I, a third portion C, a third inflection point J, a fourth portion D, a fifth portion E, and a sixth portion F.
  • the first part A is a rising curve, which indicates that the motor 12 has just started to start.
  • the nut 32 has not applied a resistance torque to the working head 14, and the first part A can be regarded as linear; the first part A is the first Inflection point K and subsequent second part B, the first inflection point K is relative to
  • the first portion A has a downwardly sloping abrupt change
  • the second portion B is a descending curve, which indicates that the nut 32 has begun to abut against the working head 14, and the nut 32 applies a resisting torque to the working head 14; after passing the second inflection point I Entering the third level C of the basic level, the working head 14 begins to overcome the resistance torque to slowly loosen the nut 32; as time passes, the third portion C undergoes a downward jump at the third inflection point J, and Forming a fourth portion D that is significantly lowered, at which point the nut 32 is nearly completely released; then entering the fifth portion E, which is substantially a horizontal straight line, indicating that the
  • Fig. 4 depicts a graph of current supplied to the motor 12 over time when the electric impact wrench 10 is used to remove the loose nut 32 coupled with the bolt 34; wherein the letter t indicates that the motor 12 is operating. Time, the letter i represents the current value of the motor 12 supplied to the electric impact wrench 10.
  • the initial portion M is a rising curve indicating that the motor 12 has just started to start, at which time the nut 32 has not applied a resisting torque to the working head 14, and the initial portion M can be considered to be linear; following the subsequent intermediate portion of the initial portion F Part N, the middle portion N is a descending curve, which means that the nut 32 has begun to abut against the working head 14, and the nut 32 applies a resisting torque to the working head 14; since the nut 32 and the bolt 34 are not tightly coupled, the working head 14 is short.
  • the nut 32 and the bolt 34 are loosened at this time, and directly enter the substantially horizontal portion (not labeled), which is basically a horizontal straight line, indicating that the nut 32 has been completely loosened, and the motor 12 is in an idle state; Finally, the final part O is entered, at which time the motor 12 is turned off and the current i is also reduced to zero.
  • the parameter x is the current value of the motor 12 supplied to the electric impact wrench 10
  • the preset function f(x) is the first derivative value of the parameter x
  • the aforementioned preset condition is Therefore, the current value of the motor 12 supplied to the electric impact wrench 10 is less than the preset current threshold, and the first derivative of the current value is equal to or smaller than the preset derivative threshold.
  • the current i will generate noise, and the current i will appear as an irregular curve or burr on the relationship of time t, thereby affecting the calculation of the first derivative value.
  • the following steps may be included in the calculation of the first derivative value, and the current may be measured at a plurality of consecutive time intervals, the current values of which are i1, i2, i3, ... in, respectively. And respectively Calculate the first derivative di1/dt1, di2/dt2, di3/dt3...din/dtn for the measured currents i1, i2, i3, ... in for time, and obtain the average of the obtained n di/dt Then, the value of the average is judged whether it meets the threshold smaller than the preset derivative.
  • the current value of the current supplied to the motor 12 can be obtained by collecting the current value multiple times and obtaining an average value, thereby reducing the current value error caused by the current fluctuation, which will not be described herein.
  • the preset current threshold in the preset condition is set as the current value of the preset position in the fourth part D in FIG. 3, and the preset derivative threshold is the first derivative value of the current.
  • the preset derivative threshold is the first derivative value of the current; in the fourth function D or the graph in the preset function f(x)
  • the first derivative value of the current value of the preset position in the middle portion N of 4 indicates that the current drops sharply, the nut 32 has been loosened with the bolt 34, and the third motor shifting sub-module 464c further changes the rotational speed of the motor 12.
  • the third motor shifting sub-module 464c includes a third timing acquisition unit 4642c, a timing determination unit 4464, and a motor control unit 4646.
  • the third time acquiring unit 4642c starts counting.
  • the third time acquiring unit 4642c generates the current time.
  • the target control unit 4464 outputs a preset time T1 as the target time T2, and the motor control unit 4646 selects a different mode of changing the motor rotation speed based on the target time T2 and the preset time T1.
  • the time determining unit 4464 outputs a corresponding control command to the motor control unit 4646, and the motor control unit 4646 passes the first preset. After the length of time, the motor 12 is turned off; thereby loosening the nut 32 and the bolt 34 sufficiently, but the two are not disengaged.
  • the first preset duration can be based on the required stroke of the nut 32 from the current position to the complete detachment of the bolt.
  • the row is set so that at the end of the first preset duration, the nut 32 is still not deviated from the bolt 34; preferably, the first predetermined duration is 10 milliseconds.
  • the target timing T2 is before the preset time T1
  • the timing determining unit 4464 outputs another control command to the motor control unit 4646, and the motor control unit 4646 immediately shuts down the motor. 12; thereby preventing the nut 32 and the bolt 34 from being disengaged.
  • shutdown motor includes stopping and braking the motor, and will not be described here.
  • the nut 32 can be rotated out of the bolt 34 to the maximum extent, but not separated from the bolt 34, reducing manual operation by the user. The time taken to remove the nut 32 greatly increases the user experience.
  • control system 40 is different from the other embodiments only in that the control system 40 further includes a preset module 41, and the preset module 41 includes The instruction preset sub-module 412, the instruction acquisition sub-module 414, and the instruction matching sub-module 416.
  • the command preset sub-module 412 is configured to preset a speed control demand instruction set, and includes a plurality of speed control demand instructions, and each speed control demand instruction corresponds to a specific manner of the step of changing the rotation speed of the motor;
  • the sub-module 414 is configured to obtain a user speed adjustment demand instruction;
  • the instruction matching sub-module 416 is configured to confirm the specific manner of the step of changing the motor speed according to the user speed adjustment demand instruction.
  • the third motor shift sub-module 464c changes the motor speed in accordance with the manner confirmed by the command matching sub-module 416.
  • different shift modes are set, for example, the long stroke is set to the first shift mode, and the medium and short strokes are set to the second shift mode; the user according to the different stroke of the nut
  • the optimal user speed control demand command is issued to obtain the most suitable mode for changing the motor speed; then, the third motor speed shift sub-module 464c changes the motor speed through the shift mode.
  • the user can select the way to change the motor speed according to the working conditions, and improve the control system.
  • the adaptability of different working conditions ensures that the nut can always be removed to the optimal position under different working conditions.
  • the mode switching button is set on the electric impact wrench and the mode icon is marked on the circumference of the button, so that the user can operate the dial button to select the corresponding shift mode before use.
  • control system 40 is different from the first embodiment of the third inventive concept in that the control system 40 further includes a clock module 43, the clock module. 43 is used to provide a time start point, and the control module starts the detection parameter x at the time start.
  • the time starting point is a time node after the second preset time period after the power tool is turned on.
  • the foregoing time starting point may be T0 time, the current i at time T0 is located in the second part B in FIG. 3 and the middle part N in FIG. 4; before the T0 time, the control system does not start.
  • the control system starts to start and acquires the parameter x through its detection module.
  • the second preset duration may also be 0, and the aforementioned starting point of time is 0.
  • the control system By setting the second preset duration, when the control system is started, the working head has been pressed against the nut, the nut has begun to apply a resisting torque to the working head, and the nut is about to be slowly released; so that the control system can detect it faster.
  • the preset function f(x) meets the preset condition, it is avoided that in the first part A or the initial part M, the working head is not yet in contact with the nut, resulting in the work efficiency and energy caused by the control system having no working demand. waste.
  • control system is compared with the first embodiment of the third inventive concept of the present invention; the only difference is that the preset function f(x) is the second derivative of the parameter x
  • the preset condition is that the preset function f(x) is also equal to or smaller than the preset derivative threshold.
  • the preset function f(x) can also be a multi-order derivative of the parameter x, and will not be described here.
  • the control system is different from the first embodiment of the third inventive concept of the present invention only in that the parameter x and the preset function f(x) are both in compliance with each other.
  • the third motor shift sub-module 464c turns off the motor after the motor runs the preset number of turns.
  • control system is different from the fifth embodiment of the third inventive concept of the present invention only in that the parameter x and the preset function f(x) are both in compliance with each other.
  • the third motor shifting sub-module 464c turns off the motor after lowering the motor speed.
  • the control system is different from the fifth embodiment of the third inventive concept of the present invention only in that the parameter x and the preset function f(x) are both in compliance with each other.
  • the third motor shifting sub-module 464c lowers the motor speed, prompting the user by the speed reduction, so that the user manually shuts down the motor.
  • the control system is different from the fifth embodiment of the third inventive concept of the present invention only in that the parameter x and the preset function f(x) are in compliance with each other. Whether the target time T2 at which the condition is located is after or after the preset time T1, the third motor shifting sub-module 464c can prompt the user to make the user manually close by periodically switching the motor between continuous forward and reverse rotations. Stop the motor.
  • the control system can loosen the nut and the bolt without separating the nut and the bolt, and the user can manually separate the nut and the bolt according to the requirement, so that the user only needs to loosen the nut. Special working conditions.
  • control method of the power tool includes the following steps:
  • step S20 a parameter x indicating the load of the output shaft 16 is detected.
  • the nut 32 passes through the working head 14 to the output of the electric impact wrench 10 due to the presence of the thread fastening force between the nut 32 and the bolt 34.
  • the shaft 16 applies a resistive torque.
  • the working head 14 begins to tighten or remove the nut 32.
  • the resistance torque is proportional to the thread fastening force between the nut 32 and the bolt 34.
  • the thread fastening force between the nut 32 and the bolt 34 is also gradually increased, and the nut 32 and the bolt 34 are When fully tightened, the thread tightening force reaches a peak; conversely, during the removal of the nut 32 by the electric impact wrench 10, the thread tightening force is already at a peak, and the resistance of the output shaft 16 of the electric impact wrench 10 at the initial moment is The moment is the largest.
  • the motor 12 of the electric impact wrench 10 needs to output a large rotating torque to overcome the resistance torque at the peak, and the resistance of the output shaft 16 of the electric impact wrench 10 after the nut 32 and the bolt 34 are completely tightened. Moment reduced to gentle, motor The rotational torque of the 12 outputs is also reduced to a gentle level.
  • the parameter x is used to indicate the load of the output shaft 16 of the electric impact wrench 10, that is, the resistance torque that the output shaft 16 of the electric impact wrench 10 is subjected to, and the resistance torque is consistent with the output torque of the motor 12 of the electric impact wrench 10,
  • the parameter related to the output torque of the motor 12 as the aforementioned parameter x
  • the magnitude of the load of the output shaft 16 can be identified by monitoring the parameter x.
  • step S40 the preset function f(x) of the parameter x is calculated.
  • step S60 it is determined that the output shaft load is reduced to be equal to or less than a preset load according to the parameter x and its preset function f(x) according to a preset condition, thereby changing the rotational speed of the motor.
  • Step S60 specifically includes:
  • step S622 determining whether the parameter x meets the preset condition, if yes, executing step S624; if not, returning to step S20;
  • step S624 determining whether the preset function f(x) of the parameter x meets the preset condition, and if so, executing step S64; if not, returning to step S20;
  • FIG. 3 depicts a current curve of the current supplied to the motor 12 when the nut 32 is tightly coupled with the bolt 34, and the letter t indicates that the motor 12 starts to work. At the time, the letter i indicates the current value of the motor 12 supplied to the electric impact wrench 10.
  • the curve in FIG. 3 includes a first portion A, a first inflection point H, a second portion B, a second inflection point I, a third portion C, a third inflection point J, a fourth portion D, a fifth portion E, and a sixth portion F.
  • the first part A is a rising curve, which indicates that the motor 12 has just started to start.
  • the nut 32 has not applied a resistance torque to the working head 14, and the first part A can be regarded as linear;
  • the first part A is the first The inflection point K and the subsequent second portion B, the first inflection point K has a downwardly inclined abrupt change with respect to the first portion A, and the second portion B is a descending curve, which indicates that the nut 32 has begun to abut against the working head 14, the nut 32 applies a resistance torque to the working head 14; after passing the second inflection point I, enters the third portion C of the basic level, at which time the working head 14 begins to overcome the resistance torque to slowly loosen the nut 32; as time passes, the third Part C undergoes a downward transition at the third inflection point J and forms a fourth portion D that is significantly lowered, at which point the nut 32 is nearly completely released;
  • the part is basically a horizontal straight line, indicating that the
  • Fig. 4 depicts a graph of current supplied to the motor 12 over time when the electric impact wrench 10 is used to remove the loose nut 32 coupled with the bolt 34; wherein the letter t indicates that the motor 12 is operating. Time, the letter i represents the current value of the motor 12 supplied to the electric impact wrench 10.
  • the initial portion M is a rising curve indicating that the motor 12 has just started to start, at which time the nut 32 has not applied a resisting torque to the working head 14, and the initial portion M can be considered to be linear; following the subsequent intermediate portion of the initial portion F Part N, the middle portion N is a descending curve, which means that the nut 32 has begun to abut against the working head 14, and the nut 32 applies a resisting torque to the working head 14; since the nut 32 and the bolt 34 are not tightly coupled, the working head 14 is short.
  • the nut 32 and the bolt 34 are loosened at this time, and directly enter the substantially horizontal portion (not labeled), which is basically a horizontal straight line, indicating that the nut 32 has been completely loosened, and the motor 12 is in an idle state; Finally, the final part O is entered, at which time the motor 12 is turned off and the current i is also reduced to zero.
  • the parameter x is the current value of the motor 12 supplied to the electric impact wrench 10
  • the preset function f(x) is the first derivative value of the parameter x
  • the aforementioned preset condition is Therefore, the current value of the motor 12 supplied to the electric impact wrench 10 is less than the preset current threshold, and the first derivative of the current value is equal to or smaller than the preset derivative threshold.
  • the current i will generate noise, and the current i will appear as an irregular curve or burr on the relationship of time t, thereby affecting the calculation of the first derivative value.
  • the following steps may be included in the calculation of the first derivative value, and the current may be measured at a plurality of consecutive time intervals, the current values of which are i1, i2, i3, ... in, respectively.
  • the first derivatives di1/dt1, di2/dt2, di3/dt3, ... din/dtn are obtained for the measured currents i1, i2, i3, ..., respectively, and the obtained n di/dt are obtained.
  • the average is then judged whether the value of the average is consistent with a threshold less than the preset derivative.
  • the current value of the current supplied to the motor 12 can be obtained by collecting the current value multiple times and obtaining an average value, thereby reducing the current value error caused by the current fluctuation, which will not be described herein.
  • the preset current threshold in the preset condition is set as the first derivative value of the current value in the preset position in the fourth portion D in FIG. 3, which is also the middle portion in FIG.
  • the first derivative value of the current value of the preset position in N; the first derivative of the current value at the preset position in the fourth portion D of FIG. 3 or the intermediate portion N of FIG. 4 in the preset function f(x) The value indicates a sharp drop in current, the nut 32 has been loosened with the bolt 34, and the third motor shift sub-module 464c in turn changes the speed of the motor 12.
  • the target time T2 is after the preset time T1, after the first preset time period is passed through S646, the motor 12 is turned off; thereby fully loosening the nut 32 and the bolt 34. But the two will not leave.
  • the first preset duration may be set according to the required stroke of the nut 32 from the current position to the complete disengagement of the bolt, so that at the end of the first preset duration, the nut 32 will still not be disengaged from the bolt 34 as a reference; preferably, the first The preset duration is 10 milliseconds.
  • the target time T2 is immediately turned off by the S648 before the preset time T1; thereby preventing the nut 32 and the bolt 34 from being disengaged.
  • shutdown motor includes two steps of stopping and braking the motor, and will not be described here.
  • the nut 32 can be rotated out of the bolt 34 to the maximum extent, but not separated from the bolt 34, reducing manual operation by the user. The time taken to remove the nut 32 greatly increases the user experience.
  • control method is different from the other embodiments in that the control method further includes the step S10 before the step S20, which specifically includes:
  • a preset speed regulation demand instruction set which includes a plurality of speed regulation demand instructions, and each speed adjustment demand instruction corresponds to a specific manner of the step of changing the rotation speed of the motor;
  • step S80 changes the motor speed through the shift mode.
  • the user can select the way to change the motor speed according to the working condition, and improve the adaptability of the control method to different working conditions, thereby ensuring that the nut can always be removed to the optimal position under different working conditions.
  • the mode switching button is set on the electric impact wrench and the mode icon is marked on the circumference of the button, so that the user can operate the dial button to select the corresponding shift mode before use.
  • control method method is different from the first embodiment of the third inventive concept of the present invention in that the control method further includes step S30, which is S30 specifically includes: providing a time start point, and step S20 is started at the time start point.
  • the time starting point is a time node after the second preset time period after the power tool is turned on.
  • the foregoing time starting point may be T0 time, the current i at time T0 is located in the second part B in FIG. 3 and the middle part N in FIG. 4; before the T0 time, the control method does not start.
  • the start of step S20 is started.
  • the second preset duration may also be 0, and the aforementioned starting point of time is 0.
  • the control method By setting the second preset duration, when the control method is started, the working head has been pressed against the nut, the nut has begun to apply a resistance torque to the working head, and the nut is about to be slowly released; so that the control method can detect more quickly.
  • the preset function f(x) meets the preset condition, it is avoided that in the first part A or the initial part M, the working head is not yet in contact with the nut, resulting in the work efficiency and energy caused by the control method having no working demand. waste.
  • control method is compared with the first embodiment of the third inventive concept of the present invention; the only difference is that the preset function f(x) is the second derivative of the parameter x
  • the preset condition is that the preset function f(x) is also equal to or smaller than the preset derivative threshold.
  • the preset function f(x) can also be a multi-order derivative of the parameter x, and will not be described here.
  • the control method is different from the first embodiment of the third inventive concept of the present invention only in that the parameter x and the preset function f(x) are both in compliance with each other.
  • the step S646 is adjusted to: shut down the motor after the motor runs the preset number of turns.
  • control system is different from the fifth embodiment of the third inventive concept of the present invention only in that the parameter x and the preset function f(x) are both in compliance with each other.
  • the step S646 is adjusted to: turn off the motor after reducing the motor speed.
  • the control system is different from the fifth embodiment of the third inventive concept of the present invention only in that the parameter x and the preset function f(x) are both in compliance with each other.
  • the step S646 is adjusted to: reduce the motor speed, and prompt the user by the speed decrease, so that the user manually shuts down the motor.
  • the control system is different from the fifth embodiment of the third inventive concept of the present invention only in that the parameter x and the preset function f(x) are in compliance with each other. It is determined whether the target time T2 at which the condition is located is after or after the preset time T1, and both of steps S646 and S648 can be adjusted such that the motor periodically switches between continuous forward and reverse. By prompting the user in this way, the user manually shuts down the motor.
  • the present invention also provides a first embodiment under the fourth inventive concept.
  • the power tool is Impact wrench.
  • the impact wrench can optionally loosen or tighten the nut. In the process of loosening the nut by the impact wrench, any one of the control methods of the first invention concept, the second invention concept, and the third invention concept described above is executed.
  • the present invention also provides a second embodiment of the fourth inventive concept.
  • the power tool is an impact wrench.
  • the impact wrench can optionally be rotated forward or reverse. In the process of inverting the impact wrench, any of the control methods according to the first inventive concept, the second inventive concept, and the third inventive concept described above is executed.
  • the power tool is an impact wrench.
  • the impact wrench includes a motor and an output shaft that connects the motor.
  • the impact wrench can optionally loosen or tighten the nut.
  • the control method of the embodiment comprises the steps of: detecting a parameter characterizing the output shaft load; determining whether the release condition is satisfied, the release condition indicating that the nut is converted from the tightened state to the loosened state. State; when the release condition is satisfied, the rotation speed of the motor is changed.
  • the release condition is that the parameter x, or at least one of the functions f(x) of the parameter x, meets a preset condition.
  • the power tool further includes a system starting component, a system startup component operable start control system, and the control system is the first inventive concept and the second invention. Any of the control systems provided under the concept and the third inventive concept.
  • the power tool is an impact wrench that selectively loosens or tightens the nut, and when the impact wrench performs a loosening nut action, the operating system activation component activates the aforementioned control system.
  • the power tool is an impact wrench, and the impact wrench is selectively forward or reverse. When the impact wrench performs a reverse action, the operating system activation component activates the aforementioned control system.
  • the control method can loosen the nut and the bolt without separating the nut and the bolt, and the user can manually separate the nut and the bolt according to the requirement, so that the user only needs to loosen the nut. Special working conditions.
  • Fig. 22 shows a power tool according to a preferred embodiment of the fifth invention for mounting a screw, the electric tool comprising a motor, a working head, a power source, a detecting element 10' and a control module 20'.
  • the working head After the motor is started, the working head outputs power, and the power source is used to power the motor.
  • the detecting element 10' is for detecting a parameter characterizing the head load and outputting a detection signal.
  • Control module 20' is used to connect When the detection signal output from the detecting element 10' is judged based on the detection signal to judge that the load of the working head is reduced, the control module 20' controls the head to intermittently output power, thereby changing the output mode.
  • the way to change the output mode also includes reducing the speed, stopping, intermittently outputting power, etc., and changing the output mode of the motor to the working head.
  • the above power tool is provided with a detecting element 10' for detecting parameters indicative of the head load in real time.
  • the detecting component 10' can detect that the parameter characterizing the working head load occurs due to the change of the mounting state of the screw.
  • the control module 20' intermittently outputs power according to the detection sent by the detecting component 10', thereby achieving monitoring of the screw slip or the working head jumping out of the screw head groove, changing the power tool The working condition and the purpose of improving the working efficiency of the screw installation.
  • the control module 20' shields the detection and reception of the detection signal within a preset time after the motor is started. In other embodiments, shielding may also be performed by means of the detection element 10' being turned off within a preset time after the motor is started.
  • the parameter indicative of the head load detected by the detecting element 10' is the current flowing through the motor.
  • the control module 20' can determine the load of the working head based on the change in the current value.
  • the control module 20' determines that the load of the head is decreased.
  • the difference between the maximum value and the minimum value of the parameter is positive during a certain period of time and is not less than the first threshold. More preferably, the difference between the parameter value at the first time point and the parameter value at the last time point in a certain period of time is positive and not less than the first threshold.
  • the embodiment is directed to the case where the working head is completely slipped relative to the screw cap, and the load of the electric tool is sharply reduced after the slipping, thereby appearing in the The amount of decrease in the load parameter over a certain period of time is not less than the first threshold.
  • the working head frequently slips relative to the screw cap, that is, after the working head and the screw cap slip, the working head and the screw cap are immediately engaged, and then the working head and the screw cap are again slipped, and then the working head is The screw cap is then engaged immediately, so that it is cycled multiple times. Since each working head and the screw cap slip for a short time and then immediately engage, the load will appear a short, small decrease and then increase, so the load parameter is reduced less than the first threshold for a period of time. But greater than or equal to the second threshold, the first threshold is greater than the second threshold. In response to this situation, the present invention proposes the following two preferred embodiments.
  • control module 20' determines that the load on the head is reduced when the parameter characterizing the head load occurs at least twice during a certain period of time and the two decreases are intermittent. In another embodiment, the control module 20' determines the working head when the state in which the decreasing amount of the parameter indicating the working head load is less than the first threshold and the value greater than or equal to the second threshold occurs at least twice in the preset time period. The load is reduced.
  • control module 20' determines that the parameter characterizing the head load is decreased once when the parameters characterizing the head load are sequentially decreased at at least three adjacent points in time. In one embodiment, when the parameters characterizing the head load at at least three adjacent points in time are sequentially decreased, the control module 20' determines that the amount of decrease in the parameter characterizing the head load is less than the first threshold and is greater than or A state equal to the second threshold occurs once.
  • control module 20' determines the load reduction of the working head based at least in part on the first derivative, the second derivative, or the higher derivative of the parameter characterizing the head load.
  • the load reduction of the working head is determined based at least in part on the first derivative, including but not limited to the following cases: 1) the first derivative is negative, and the absolute value is greater than or equal to the preset value, 2) consecutive N first derivative values are Negative, and the absolute value is greater than or equal to the preset value, 3) consecutive N first-order derivative values are negative, and part of the absolute value is greater than or equal to the preset value, part is less than the preset value, 4) consecutive N ones
  • the order derivatives are all negative, and the absolute value of the latter first derivative is not less than the absolute value of the previous first derivative, that is, the continuous N first derivatives are negative and their absolute values are gradually increased, 5) consecutive N ones
  • the order derivatives are all negative and their absolute values are parabolic, that is, the continuous N first-order derivatives are negative and their absolute values increase
  • the function of the first-order derivative is greater than or equal to the preset value, and the function is Any possible function that exists in mathematics.
  • the case where the load reduction of the working head is judged based in part on the second derivative or the higher order derivative, including but not limited to, is similar to the case where the load reduction of the working head is determined based at least in part on the first derivative, including but not limited to, and is no longer List one by one.
  • control module 20' determines that the load of the head is reduced when the function of the first derivative or the first derivative of the parameter characterizing the head load is negative and its absolute value is not less than the second threshold.
  • the control module 20 'Determine the load on the work head is reduced.
  • At least one of the functions of the second derivative, the second derivative function, the higher derivative, the higher derivative of the parameter characterizing the head load is a negative value and the absolute value thereof is not less than the fifth threshold.
  • the control module 20' determines that the load of the working head is reduced, the control module 20' outputs a discontinuous supply current to the motor by controlling the power source to intermittently output power to the working head.
  • the intermittent supply current corresponds to the supply current of the interrupted pulses. That is, the control module 20' corresponds to a supply current that outputs a pulse to the motor by controlling the power source to intermittently output power to the head.
  • the working head In the normal output state, the working head continuously outputs power to complete the screw installation. In the state where the working head intermittently outputs power, it can adapt to the working condition of large torque, better control the process of installing the screw, effectively reduce the screw slip or the working head jumps out of the screw head groove, etc., so that the working head load is reduced. The occurrence of the state improves the success rate and working efficiency of the mounting screws.
  • the power tool also includes an adjustment member 30' that is steerable and transmits an adjustment signal that the operator can operatively control.
  • the control module 20' acquires the adjustment signal and adjusts the intermittent supply current of the power supply to the motor based on the adjustment signal.
  • the power tool can work in a mode with adjustable pulse frequency, adjustable pulse duty cycle, and adjustable pulse frequency and pulse duty cycle. Therefore, according to the actual situation, the appropriate output frequency and the capacity ratio are selected to meet the requirements of different working conditions.
  • control module 20' adjusts the intermittent supply current of the power supply to the motor by adjusting at least one of the time width of the single supply current or the time interval between the two adjacent supply currents. It is equivalent to adjusting the supply current of the pulse output from the power source to the motor by adjusting at least one of the time width of the supply current of the single pulse or the time interval between the supply currents of the adjacent two pulses.
  • the above-mentioned electric tool can detect the change of the current flowing through the motor during the process of installing the screw through the detecting component 10', thereby detecting the change of the load of the working head, and thereby intermittently outputting the power through the control module 20', thereby effectively reducing the power.
  • the occurrence of the slip state improves the efficiency of screw installation.
  • the working head includes a first working head and a second working head mounted to the rotating head.
  • the first working head and the second working head are switchably connected to the motor by rotation of the rotating head, and are alternatively driven by the motor.
  • the control module 20' determines, based on the detection signal, that the amount of decrease in the load of the first working head is not less than the first threshold value for a certain period of time, and the control head intermittently outputs power.
  • the control module 20' controls the second working head to continuously output power.
  • the operator can select the first working head or the second working head to output torque as needed.
  • the first working head is a screwdriver and the second working head is used to realize a drill having a constant output torque.
  • the second working head can also be a working head of an electric wrench, a hammer or an impact drill.
  • the power tool also includes a trigger member and a sensing member.
  • the trigger member is disposed on the first working head and/or the second working head.
  • the sensing component is disposed on the main body of the power tool and rotates relative to the triggering member for sensing the triggering component, and sends a sensing signal to the control module 20' according to the sensing result, and the control module 20' determines the first working head of the motor driving according to the sensing signal.
  • Two work heads Specifically, during the switching between the first working head and the second working head, when the sensing component senses the triggering component, the triggering component is rotated to the position corresponding to the sensing component with the first working head and/or the second working head.
  • the sensing element outputs an electrical signal to the sensing element 10'.
  • the first working head When the first working head is rotated to a predetermined position corresponding to the sensing member, the first working head is in an operating state, and the detecting member 10' detects a parameter characterizing the first working head load. When the second working head is in the working state, the detecting element 10' does not need to detect the parameters characterizing the first working head and the second working head load.
  • the power tool can detect and automatically load the corresponding output mode after switching to the first working head, complete the automatic switching of the output mode, and improve the working efficiency of the power tool.
  • FIG. 23 is a schematic diagram of a power tool control method according to a fifth invention, which is used for mounting a screw, and includes the following steps:
  • S120 Output a detection signal according to a parameter characterizing the workload of the working head.
  • the reception of the detection signal is masked within a preset time after startup.
  • the step of detecting the operating parameters of the power tool may further include the step of: shielding the detection of the parameter characterizing the working head load within a preset time after the startup, thereby improving the accuracy of the detection.
  • the parameter characterizing the head load is the current flowing through the motor.
  • the step of determining the load reduction of the working head according to the detection signal is specifically: determining the load of the working head when the parameter indicating the load of the working head load is not less than the first threshold in a certain period of time Reduced.
  • the specific step of determining the load reduction of the working head according to the detection signal is: when the parameter characterizing the head load occurs at least twice in a certain period of time, and when the two times decrease occurs, The control module 20' determines that the load of the work head is reduced.
  • the specific step of determining the load reduction of the working head according to the detection signal is: determining parameters for characterizing the head load when the parameters characterizing the head load at at least three adjacent time points are sequentially decreased. Decrease once.
  • the specific step of determining the load reduction of the working head according to the detection signal is: when the function of the first derivative or the first derivative of the parameter characterizing the head load is a negative value and the absolute value thereof is not When less than the second threshold, the control module 20' determines that the load of the head is decreasing.
  • the specific step of determining the load reduction of the working head according to the detection signal is: when the first derivative of the parameter characterizing the head load is a negative value and the absolute value thereof is not less than the third threshold, and the working head is characterized When the value of the parameter of the load is lower than the fourth threshold, the control module 20' determines that the load of the working head is reduced.
  • the specific step of determining the load reduction of the working head according to the detection signal is: in the function of characterizing the second derivative, the function of the second derivative, the high derivative or the high derivative of the parameter of the working head load
  • the control module 20' determines that the load of the working head is reduced.
  • the working head is in the normal output state of continuous output power.
  • control module 20 adjusts the working state of the working head to output the power state, so that the working head intermittently outputs power, thereby changing the mounting manner, avoiding the screw slipping and the working head jumping out of the groove of the screw head.
  • the step of controlling the intermittent output power of the working head is specifically: adjusting the intermittent supply current output to the motor by adjusting at least one of the time width of the single supply current or the time interval between the adjacent two supply currents.
  • the supply current of the pulse output by the power source to the motor is adjusted by adjusting at least one of a time width of a supply current of a single pulse or a time interval between supply currents of two adjacent pulses.
  • the above electric power tool control method further includes the following steps: when the working head intermittently outputs power, the power tool is restarted after the power tool is turned off, and the working head continuously outputs power.
  • the working head continuously outputs power when the working head intermittently outputs the power preset time.
  • the preset time can be adjusted according to the operator's needs to automatically return to the normal output mode for quick screw tightening.
  • the power tool includes a switchable first working head and a second working head.
  • the first working head and the second working head are switchably connected to the motor by rotation of the rotating head.
  • the operator can select the first working head or the second working head to output power as needed.
  • the first working head is used to implement the screwdriver function
  • the second working head is used to realize the drilling function with constant output torque.
  • the step of detecting the operating parameters of the power tool further includes the steps of: determining whether the first working head is working, and if so, performing the step of detecting the working parameter to characterize the working head load.
  • the specific step of determining whether it is the first working head is: sensing the triggering component, and sending the sensing signal to the control module 20' according to the sensing result, and the control module 20' determines that the first working head or the second working head is driven by the motor according to the sensing signal.
  • the power tool can automatically load different output modes according to the first working head, and automatically switch the output mode according to different working heads to improve work efficiency.
  • the screw slip by detecting the parameters characterizing the load of the working head, the screw slip can be obtained, and the load of the working head is reduced, thereby automatically adjusting the working mode of the power tool, thereby changing the working state of the power tool working head.
  • the occurrence of the screw slip state is reduced.
  • different working modes can be automatically loaded to meet the requirements of different installation conditions, and the installation efficiency and success rate of the screw are improved.

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Abstract

一种电动工具的控制方法，包括如下步骤：检测用于表示电机输出轴负载的参数x；根据参数x符合预设条件来判定输出轴负载降低至等于或小于预设负载，进而改变电机的转速。还公开了一种控制系统和应用该控制系统的电动工具。利用该电动工具的控制方法和控制系统，能够将螺母与螺栓松开却不会使二者分离，用户能够根据需求手动分离螺母和螺栓，满足用户仅需松开螺母的特殊工况需求。

Description

电动工具的控制方法及控制系统、电动工具 技术领域
本发明涉及电动工具领域，尤其涉及一种电动工具的控制方法。
本发明还涉及一种应用该控制方法的控制系统。
本发明还涉及一种应用该控制系统的电动工具。
背景技术
现有的电动工具，如电动冲击扳手，通过加载的电源提供电流，来驱动电机转动，从而使工作头旋转以将螺纹紧固件旋紧或卸除。
然而，在某些特殊工况下，比如用户在松脚手架的扣件时，由于电动冲击扳手的电机始终是高速旋转的，在极短时间内，扣件上的螺母和螺栓就被完全分离，造成扣件掉落和脚手架散架，用户难有充足的反应时间来躲闪，极易被脚手架砸伤。
现有利用电动冲击扳手对扣件进行卸除时，通常依靠用户的经验来提前关停电动充电扳手，防止扣件上的螺母和螺栓被完全分离而引发脚手架散架；由于螺母的长度较短，通过经验难以保证关停电动冲击扳手的精确性，用户经常需高频率的重复多次开启和关停电动冲击扳手的动作，才能达到施工目的，极大的降低了扣件卸除的效率，甚至不如手动螺丝刀来的效率高，极大的影响了类似电动冲击扳手的电动工具的市场前景。
此外，在使工作头旋转以将螺纹紧固件旋紧或卸除的过程中，在没有对螺钉头部施加足够的下压力的情况下或电动工具的输出扭力突然增大的情况下，会导致工作头从螺钉头部滑出，从而引起工作头相对螺钉头部打滑，造成螺钉头、工作头、或工件表面的损坏。
发明内容
本发明提供一种电动工具的控制方法，能够在螺栓上完全松开但不卸除螺母。
为达到上述发明目的，本发明提供一种电动工具的控制方法，其中电动工具包括电机及连接电机的输出轴，所述控制方法包括如下步骤：检测表示 输出轴负载的参数x；根据所述参数x符合预设条件来判定所述输出轴负载降低至等于或小于预设负载，进而改变所述电机的转速。
优选的，所述参数x为供给电机的电流值、输出轴的输出扭矩值、或电动工具的加速度值中的一个；所述预设条件包括：所述参数X等于或小于第一预设阈值。
优选的，所述参数x为供给电机的电流值、输出轴的输出扭矩值、或电动工具的加速度值中的一个；所述预设条件包括：在第三预设时长内，所述参数X持续等于或小于第一预设阈值。
优选的，所述参数x为供给电机的电流值、输出轴的输出扭矩值、或电动工具的加速度值中的一个；所述预设条件包括：所述参数由大于或等于第二预设阈值降低为小于或等于第一预设阈值。
优选的，所述改变电机的转速的步骤的具体方式包括：以电动工具电机启动为起算时刻，获取所述参数x符合所述预设条件时的目标时刻；当目标时刻在预设时刻之后时，经过第一预设时长后关停电机、或在电机运转预设圈数后关停电机、或降低电机转速。
优选的，所述改变电机的转速的步骤的具体方式包括：以电动工具电机启动为起算时刻，获取所述参数x符合所述预设条件时的目标时刻；当目标时刻在预设时刻之前时，即时关停电机。
为实现上述发明目的，本发明还提供另外一种电动工具的控制方法，其中电动工具包括电机及连接电机的输出轴，所述控制方法包括如下步骤：检测表示输出轴负载的参数x；计算所述参数x的预设函数f(x)；根据所述预设函数f(x)符合预设条件来判定所述输出轴负载降低至等于或小于预设负载，进而改变所述电机的转速。
优选的，所述预设函数f(x)为参数x的N阶导数，所述N为正整数；所述预设条件为：预设函数f(x)的值等于或小于预设导数阈值。
优选的，所述参数x为供给电机的电流值或输出轴的输出扭矩值。
优选的，所述改变电机转速的步骤的具体方式为：获取所述预设函数f(x) 符合所述预设条件时的目标时刻，该目标时刻自电动工具电机启动后起算；当目标时刻在预设时刻之后时，在经过第一预设时长后关停电机、或在电机运转预设圈数后关停电机、或降低电机转速。
优选的，所述改变电机转速的步骤的具体方式为：获取所述预设函数f(x)符合所述预设条件时的目标时刻，该目标时刻自电动工具电机启动后起算；
当目标时刻在预设时刻之前时，即时关停电机。
为实现上述发明目的本发明还提供另外一种电动工具的控制方法，其中电动工具包括电机及连接电机的输出轴，所述控制方法包括如下步骤：检测表示输出轴负载的参数x；计算参数x的预设函数f(x)；根据所述参数x及其预设函数f(x)符合预设条件来判定所述输出轴负载降低至等于或小于预设负载，进而改变所述电机的转速。
优选的，所述参数x为供给电机的电流值，所述预设函数f(x)为参数x的一阶导数值；所述预设条件包括：给电机所述供的电流值小于第一预设阈值，所述供给电机的电流值的一阶导数值为负。
优选的，所述改变电机的转速的步骤的具体方式为：以电动工具电机启动为起算时刻，获取所述参数x及其预设函数f(x)符合所述预设条件时的目标时刻；在目标时刻在预设时刻之后时，在经过第一预设时长后关停电机、或在电机运转预设圈数后关停电机、或降低电机转速。
优选的，所述改变电机的转速的步骤的具体方式为：以电动工具电机启动为起算时刻，获取所述参数x及其预设函数f(x)符合所述预设条件时的目标时刻；在目标时刻在预设时刻之前时，即时关停电机。
优选的，在所述电动工具中电机启动并经过第二预设时长后，开始检测用于表示输出轴负载的参数x。
优选的，所述控制方法还包括检测用于表示输出轴负载的参数x之前的如下步骤：预设调速需求指令集，其包括多个调速需求指令，每个调速需求指令对应所述改变电机的转速的步骤的一种具体方式；获取用户调速需求指令；根据用户调速需求指令确认所述改变电机转速的步骤的具体方式。
优选的，所述改变电机转速的步骤具体为：控制电机在正转和反转之间周期性切换。
优选的，所述参数为供给电机的电流，所述第一预设阈值为所述电动工具在空载状态时的电流值。
优选的，所述电动工具为冲击扳手，所述冲击扳手可选择地正转或反转，当所述冲击扳手执行反转动作时，所述控制方法执行根据所述参数x或参数x的函数f(x)中的至少一个符合预设条件来判定所述输出轴负载降低至等于或小于预设负载，进而改变所述电机的转速的步骤。
优选的，所述电动工具为冲击扳手，所述冲击扳手可选择地松开或拧紧螺母，当所述冲击扳手执行松开螺母的动作时，所述控制方法执行根据所述参数x或参数x的函数f(x)中的至少一个符合预设条件来判定所述输出轴负载降低至等于或小于预设负载，进而改变所述电机的转速的步骤。
为实现上述发明目的，本发明还提供另外一种冲击扳手的控制方法，所述冲击扳手包括电机及连接电机的输出轴，所述冲击扳手可选择地松开或拧紧螺母，所述冲击扳手松开螺母的过程中，所述控制方法包括以下步骤：检测表征输出轴负载的参数；判断松开条件是否满足，所述松开条件表征所述螺母由拧紧状态转换为松开状态；当所述松开条件满足时，改变电机的转速。
优选的，所述松开条件为所述参数x、或参数x的函数f(x)中的至少一个符合预设条件。
与现有技术相比，本发明所提供的电动工具的控制方法，能够将螺母与螺栓完全松开却不会使螺母和螺栓分离，用户能够根据需求手动分离螺母和螺栓，满足用户仅需松开螺母的特殊工况需求。
本发明提供一种电动工具的控制系统，能够在螺栓上完全松开但不卸除螺母。
为达到上述发明目的，本发明提供一种电动工具的控制系统，其中，电动工具包括电机及连接电机的输出轴，所述控制系统包括：检测模块，检测表示输出轴负载的参数x；第一控制模块，包括：参数判断子模块，根据所 述参数x符合预设条件来判定所述输出轴负载降低至等于或小于预设负载；第一电机变速子模块，接收参数判断子模块的信号，进而改变所述电机的转速。
优选的，所述参数x为供给电机的电流值、输出轴的输出扭矩值、或电动工具的加速度值的一个；所述预设条件包括：所述参数X等于或小于第一预设阈值。
优选的，所述参数x为供给电机的电流值、输出轴的输出扭矩值、或电动工具的加速度值中的一个；所述预设条件包括：在第三预设时长内，所述参数X持续等于或小于第一预设阈值。
优选的，所述参数x为供给电机的电流值、输出轴的输出扭矩值、或电动工具的加速度值中的一个；所述预设条件包括：所述参数由大于或等于第二预设阈值降低为小于或等于第一预设阈值。
优选的，所述第一电机变速子模块包括：第一时刻获取单元，以电动工具电机启动为起算时刻，获取所述参数x符合所述预设条件时的目标时刻；时刻判断单元，判断目标时刻是否在预设时刻之后；电机控制单元，当目标时刻在预设时刻之后时，经过第一预设时长后关停电机、或控制电机运转预设圈数后关停电机、或降低电机转速。
优选的，所述第一电机变速子模块包括：第一时刻获取单元，以电动工具电机启动为起算时刻，获取所述参数x符合所述预设条件时的目标时刻；时刻判断单元，判断目标时刻是否在预设时刻之前；电机控制单元，当目标时刻在预设时刻之前时，即时关停电机。
为实现上述发明目的，本发明还提供另外一种电动工具的控制系统，其中，电动工具包括电机及连接电机的输出轴，所述控制系统包括：检测模块，检测用于表示输出轴负载的参数x；第二计算模块，计算所述参数x的预设函数f(x)；第二控制模块，包括：函数判断子模块，根据所述预设函数f(x)符合预设条件来判定所述输出轴负载降低至等于或小于预设负载；第二电机变速子模块，接收函数判断子模块的信号，进而改变所述电机的转速。
优选的，所述预设函数f(x)为参数x的N阶导数，所述N为正整数；所述预设条件为：预设函数f(x)的值等于或小于预设导数阈值。
优选的，所述参数x为供给电机的电流值或输出轴的扭矩值。
优选的，所述第二电机变速子模块包括：第二时刻获取单元，以电动工具电机启动为起算时刻，获取所述函数f(x)符合所述预设条件时的目标时刻；时刻判断单元，判断目标时刻是否在预设时刻之后；电机控制单元，当目标时刻在预设时刻之后时，经过第一预设时长后关停电机、或控制电机运转预设圈数后关停电机、或降低电机转速。
优选的，所述第二电机变速子模块包括：第二时刻获取单元，以电动工具电机启动为起算时刻，获取所述函数f(x)符合所述预设条件时的目标时刻；时刻判断单元，判断目标时刻是否在预设时刻之前；电机控制单元，当目标时刻在预设时刻之前时，即时关停电机。
为实现上述发明目的，本发明还提供另外一种电动工具的控制系统，其中，电动工具包括电机及连接电机的输出轴，所述控制系统包括：检测模块，检测用于表示输出轴负载的参数x；第三计算模块，计算参数x的预设函数f(x)；第三控制模块，包括：参函数判断子模块，根据所述参数x及其预设函数f(x)符合预设条件来判定所述输出轴负载降低至等于或小于预设负载；第三电机变速子模块，接收参函数判断子模块的信号，进而改变所述电机的转速。
优选的，所述参数x为供给电机的电流值，所述预设函数f(x)为参数x的一阶导数值；所述预设条件包括：所述供给电机的电流值小于第一预设阈值，所述供给电机的电流值的一阶导数值为负。
优选的，所述第三电机变速子模块包括：第三时刻获取单元，以电动工具电机启动为起算时刻，获取所述参数x和函数f(x)符合所述预设条件时的目标时刻；时刻判断单元，判断目标时刻是否在预设时刻之后；电机控制单元，当目标时刻在预设时刻之后时，经过第一预设时长后关停电机、或控制电机运转预设圈数后关停电机、或降低电机转速。
优选的，所述第三电机变速子模块包括：第三时刻获取单元，以电动工具电机启动为起算时刻，获取所述参数x和函数f(x)符合所述预设条件时的目标时刻；时刻判断单元，判断目标时刻是否在预设时刻之前；电机控制单元，当目标时刻在预设时刻之前时，即时关停电机。
优选的，在所述电动工具中电机启动并经过第二预设时长后，检测模块开始检测用于表示输出轴负载的参数x。
优选的，所述控制系统还包括预设模块，所述预设模块包括：指令预设子模块，用于预设调速需求指令集，其包括多个调速需求指令，每个调速需求指令对应所述改变电机的转速的步骤的一种具体方式；指令获取子模块，用于获取用户调速需求指令；指令匹配子模块，用于根据用户调速需求指令确认所述改变电机转速的步骤的具体方式。
优选的，所述电机变速子模块控制电机在正转和反转之间周期性切换。
优选的，所述参数为供给电机的电流，所述第一预设阈值为所述电动工具在空载状态时的电流值。
与现有技术相比，本发明所提供的电动工具的控制系统，能够将螺母与螺栓完全松开却不会使螺母和螺栓分离，用户能够根据需求手动分离螺母和螺栓，满足用户仅需松开螺母的特殊工况需求。
本发明提供一种电动工具，能够在螺栓上完全松开但不卸除螺母。
为达到上述发明目的，本发明提供一种电动工具，所述电动工具包括：电源；电机，获取电源的电力以提供旋转动力；输出轴，获取电机的旋转动力并输出；如前所述的控制系统，所述控制系统与电机和电源电性连接。
优选的，所述电动工具还包括：系统启动部件，其用于可操作的启动所述控制系统。
优选的，所述电动工具为冲击扳手，所述冲击扳手可选择地松开或拧紧螺母，当所述冲击扳手执行松开螺母动作时，操作所述系统启动部件启动所述控制系统。
优选的，所述电动工具为冲击扳手，所述冲击扳手可选择地正转或反转， 当所述冲击扳手执行反转动作时，操作所述系统启动部件启动所述控制系统。
与现有技术相比，本发明所提供的电动工具，能够将螺母与螺栓完全松开却不会使螺母和螺栓分离，用户能够根据需求手动分离螺母和螺栓，满足用户仅需松开螺母的特殊工况需求。
本发明还提供一种电动工具，可自动监控是否出现打滑现象，并在出现打滑现象时采取相应的措施，以减小打滑对工作头、螺钉头、工件表面等的损坏。
为达到上述发明目的，本发明提供一种电动工具，所述电动工具包括：工作头；电机，启动后驱动所述工作头输出动力；电源，为所述电机提供动力；检测元件，检测表征所述工作头负载的参数并输出检测信号；及控制模块，接收所述检测信号，并根据所述检测信号判断所述工作头的负载减小时，控制所述工作头间断地输出动力。
为达到上述发明目的，本发明还提供另外一种电动工具，所述电动工具，驱动紧固件嵌入工件，所述电动工具包括：工作头；电机，启动后驱动所述工作头输出动力；电源，为所述电机提供动力；检测元件，检测表征所述工作头负载的参数并输出检测信号；及控制模块，根据所述检测信号判断所述工作头与所述紧固件是否分离，当判断结果为是时，中断电机向工作头的扭矩传递，所述工作头与所述紧固件相互分离的判断标准为所述工作头的负载减小。
优选的，启动所述电机后的预设时间内，所述控制模块屏蔽对所述检测信号的接收。
优选的，预设时间段内，当表征所述工作头负载的所述参数的减小量不小于第一阈值时，所述控制模块判断所述工作头的负载减小。
优选的，预设时间段内，当表征所述工作头负载的所述参数的减小量小于第一阈值且大于或等于第二阈值的状态出现至少两次时，所述控制模块判断所述工作头的负载减小。
优选的，当至少三个相邻的时间点上的表征所述工作头负载的所述参数 依次减小时，所述控制模块判断表征所述工作头负载的参数的减小量小于第一阈值且大于或等于第二阈值。
优选的，当表征所述工作头负载的所述参数的一阶导数或一阶导数的函数为负值且其绝对值不小于第二阈值时，所述控制模块判断所述工作头的负载减小。
优选的，当表征所述工作头负载的所述参数的一阶导数为负值且其绝对值不小于第三阈值，且表征所述工作头负载的所述参数的数值小于第四阈值时，所述控制模块判断所述工作头的负载减小。
优选的，当表征所述工作头负载的所述参数的二阶导数、二阶导数的函数、高阶导数或高阶导数的函数中的至少一个为负值且其绝对值不小于第五阈值时，所述控制模块判断所述工作头的负载减小。
优选的，表征所述工作头负载的所述参数为流经所述电机的电流。
优选的，所述控制模块通过控制所述电源向所述电机输出脉冲的供电电流使所述工作头间断地输出动力。
优选的，所述电动工具还包括调节元件，所述调节元件可操作地处于不同的状态，并发送与其状态对应的调节信号，所述控制模块根据所述调节信号调整所述电源向所述电机输出的脉冲的供电电流。
优选的，所述控制模块通过调整单个脉冲的供电电流的时间宽度或相邻两个脉冲的供电电流之间的时间间隔中的至少一个来调整所述电源向所述电机输出的脉冲的供电电流。
为实现上述发明目的，本发明还提供另外一种电动工具，所述电动工具包括：壳体；电机，收容在所述壳体中；第一工作头及第二工作头，所述第一工作头与所述第二工作头可择一地由所述电机驱动；检测元件，检测表征电动工具负载的参数并输出检测信号；及控制模块，接收所述检测信号，并根据所述检测信号控制所述第一工作头及第二工作头的工作；当所述第一工作头由所述电机驱动，且电动工具的负载减小时，所述控制模块中断向所述第一工作头的扭矩输出。
优选的，所述第一工作头为螺丝批。
优选的，所述第二工作头为钻头，当所述第二工作头由所述电机驱动，且第二工作头的负载大于或等于预设负载值时，所述控制模块改变向所述第二工作头的扭矩输出。
优选的，所述电动工具还包括触发件及感应件，所述触发件设置在所述第一工作头和/或第二工作头上，所述感应件设置在所述壳体上，当所述触发件靠近所述感应件时，感应件发送感应信号给所述控制模块，所述控制模块根据所述感应信号判断由所述电机驱动的是所述第一工作头或所述第二工作头。
为达到上述发明目的，本发明还提供一种电动工具控制方法，包括如下步骤：检测表征工作头负载的参数；根据表征所述工作头负载的所述参数，输出检测信号；接收所述检测信号；根据所述检测信号判断所述工作头的负载减小时，控制所述工作头间断地输出动力。
为达到上述发明目的，本发明还提供一种电动工具控制方法，电动工具驱动紧固件嵌入工件，包括如下步骤：检测表征工作头负载的参数；根据所述表征工作头负载的参数判断所述工作头与所述紧固件是否分离；当判断结果为是时，中断向工作头的扭矩传递；所述工作头与所述紧固件相互分离的判断标准为所述工作头的负载减小。
优选的，所述电动工具控制方法还进一步包括步骤：启动电机；启动所述电机后的预设时间内，屏蔽对所述检测信号的接收。
优选的，根据所述检测信号判断所述工作头的负载减小的步骤具体为：当表征所述工作头负载的所述参数在一定时间段内的减小量不小于第一阈值时，判断所述工作头的负载减小。
优选的，根据所述检测信号判断所述工作头的负载减小的具体步骤为：当表征所述工作头负载的所述参数的减小量小于第一阈值且大于或等于第二阈值的状态出现至少两次时，所述控制模块判断所述工作头的负载减小。
优选的，判断表征所述工作头负载的参数的减小量小于第一阈值且大于 或等于第二阈值的具体步骤为：判断至少三个相邻的时间点上的表征所述工作头负载的所述参数依次减小。
优选的，根据所述检测信号判断所述工作头的负载减小的具体步骤为：当表征所述工作头负载的所述参数的一阶导数或一阶导数的函数为负值且其绝对值不小于第二阈值时，判断所述工作头的负载减小。
优选的，根据所述检测信号判断所述工作头的负载减小的具体步骤为：当表征所述工作头负载的所述参数的一阶导数为负值且其绝对值不小于第三阈值，且表征所述工作头负载的所述参数的数值低于第四阈值时，判断所述工作头的负载减小。
优选的，根据所述检测信号判断所述工作头的负载减小的具体步骤为：当表征所述工作头负载的所述参数的二阶导数、二阶导数的函数、高阶导数、或高阶导数的函数中的至少一个为负值且其绝对值不小于第五阈值时，判断所述工作头的负载减小。
优选的，所述表征工作头负载的参数为流经所述电机的电流。
优选的，控制所述工作头间断地输出动力的具体步骤为：向所述电机输出脉冲的供电电流。
优选的，所述控制方法还包括以下步骤：可操作地调节设置在电动工具上的调节元件使其处于不同的状态；响应于调节元件的不同状态，调节单个脉冲的供电电流的宽度或相邻两个脉冲的供电电流之间的时间间隔。
优选的，所述电动工具控制方法还包括以下步骤：关闭所述电动工具后重启所述电动工具时，所述工作头持续输出动力。
优选的，所述电动工具控制方法还包括以下步骤：当所述工作头间断地输出动力预设时间后，所述工作头持续输出动力。
为实现上述发明目的，本发明还提供另一种电动工具控制方法，所述电动工具包括电机以及第一工作头和第二工作头，所述第一工作头和第二工作头可择一地由所述电机驱动，所述电动工具控制方法包括以下步骤：检测表征电动工具负载的参数；确认所述第一工作头是否由所述电机驱动；当所述 第一工作头由所述电机驱动时，确认电动工具的负载是否减小；当电动工具的负载减小时，改变所述电机对所述第一工作头驱动。
优选的，确认所述第一工作头是否由所述电机驱动的具体步骤为：通过设置在壳体上的感应件感应设置在第一工作头和/或第二工作头上的触发件；接收来自感应元件的感应信号；根据所述感应信号确认所述第一工作头是否由所述电机驱动。
与现有技术相比，本发明提供的电动工具及其控制方法可自动监控是否出现打滑现象，并在出现打滑现象时采取相应的措施，以减小打滑对工作头、螺钉头、工件表面等的损坏。
附图说明
以上所述的本发明的目的、技术方案以及有益效果可以通过下面的能够实现本发明的具体实施例的详细描述，同时结合附图描述而清楚地获得。
图1为本发明一较佳实施例中电动工具的结构示意图。
图2为第一发明构思下的控制系统的第一较佳实施例的具体模块图。
图3为图1所示的电动工具在松螺母时，螺母与螺栓结合紧密，供给其电机的电流随时间的变化曲线图。
图4为图1所示的电动工具在松螺母时，螺母与螺栓结合松散，供给其电机的电流随时间的变化曲线图。
图5为第一发明构思下的控制系统的第二较佳实施例的具体模块图。
图6为第一发明构思下的控制系统的第三较佳实施例的具体模块图。
图7为第一发明构思下的电动工具的控制方法的第一较佳实施例的流程图。
图8为第一发明构思下的电动工具的控制方法的第二较佳实施例的流程图。
图9为为第一发明构思下的电动工具的控制方法的第三较佳实施例的流程图。
图10为第二发明构思下的控制系统的第一较佳实施例的具体模块图。
图11为第二发明构思下的控制系统的第二较佳实施例的具体模块图。
图12为第二发明构思下的控制系统的第三较佳实施例的具体模块图。
图13为第二发明构思下的电动工具的控制方法的第一较佳实施例的流程图。
图14为第二发明构思下的电动工具的控制方法的第二较佳实施例的流程图。
图15为第二发明构思下的电动工具的控制方法的第三较佳实施例的流程图。
图16为第三发明构思下的控制系统的第一较佳实施例的具体模块图。
图17为第三发明构思下的控制系统的第二较佳实施例的具体模块图。
图18为第三发明构思下的控制系统的第三较佳实施例的具体模块图。
图19为第三发明构思下的电动工具的控制方法的第一较佳实施例的流程图。
图20为第三发明构思下的电动工具的控制方法的第二较佳实施例的流程图。
图21为第三发明构思下的电动工具的控制方法的第三较佳实施例的流程图。
图22为第五发明构思下的第一实施方式的电动工具的模块示意图。
图23为第五发明构思下的第一实施方式的电动工具控制方法的流程图。
图示中的相关元件对应编号如下：
电动工具，10                  指令预设子模块，412
电机，12                      指令获取子模块，414
工作头，14                    指令匹配子模块，416
输出轴，16                    检测模块，42
脚手架，20                    时钟模块，43
螺母，32                      第二计算模块，44a
螺栓，34                      第三计算模块，44b
控制系统，40                  第一控制模块，46a
预设模块，41                  第二控制模块，46b
第三控制模块，46c               第二部分，B
参数判断子模块，462a            第二拐点，I
函数判断子模块，462b            第三部分，C
参函数判断子模块，462c          第三拐点，J
第一电机变速子模块，464a        第四部分，D
第二电机变速子模块，464b        第五部分，E
第三电机变速子模块，464c        第六部分，F
第一时刻获取单元，4642a         初始部分，M
第二时刻获取单元，4642b         中间部分，N
第三时刻获取单元，4642c         最终部分，O
时刻判断单元，4644              电机空载电流值，I0
电机控制单元，4646              检测元件，10’
第一部分，A                     控制模块，20’
第一拐点，H                     调节元件，30’
具体实施方式
以下将结合附图所示的具体实施方式对本发明进行详细描述。但这些实施方式并不限制本发明，本领域的普通技术人员根据这些实施方式所做出的结构、方法、或功能上的变换均包含在本发明的保护范围内。
本发明所提供的控制方法和控制系统可应用于多种类型的电动工具，以下主要以电动冲击扳手10为具体实施例进行说明。
参图1所示，本发明一实施例中，电动冲击扳手10包括电机12、工作头14以及连接于电机12和工作头14之间的输出轴16；电动冲击扳手10的工作头14在电机12驱动下来卸除脚手架20上螺母32，从而将使得螺母32和螺栓34松开，便于对脚手架20进行拆卸。
电动冲击扳手10内还设置有控制系统40，控制系统40位于电路板上，用于在电动冲击扳手10进行螺母32卸除时，控制电机12的转速。
参图2所示，本发明的第一构思下所提供控制系统40的第一实施例中，控制系统40包括检测模块42以及第一控制模块46a。
检测模块42用于检测表示输出轴16负载的参数x。
电动冲击扳手10在扭转螺母32对其进行紧固或卸除的过程中，由于螺母32与螺栓34之间的螺纹紧固力的存在，螺母32会通过工作头14对电动冲击扳手10的输出轴16施加一个阻力矩，在电动冲击扳手10中电机12所输出的转动扭矩克服该阻力矩时，工作头14开始紧固或卸除螺母32。
阻力矩与螺母32和螺栓34之间的螺纹紧固力成正比，在螺母32拧入螺栓34的过程中，螺母32和螺栓34之间螺纹紧固力也逐渐增加，在螺母32和螺栓34被完全拧紧时，螺纹紧固力达到峰值；反之，在电动冲击扳手10卸除螺母32的过程中，螺纹紧固力已经处在峰值，初始时刻，电动冲击扳手10的输出轴16所承受的阻力矩最大，此时需要电动冲击扳手10中电机12输出较大的转动扭矩来克服位于峰值的阻力矩，在螺母32和螺栓34脱离完全拧紧后，电动冲击扳手10的输出轴16所承受的阻力矩降低至平缓，电机12所输出的转动扭矩也同步降低至平缓。
参数x用于表示电动冲击扳手10输出轴16的负载，即用于表示电动冲击扳手10输出轴16所承受的阻力矩，由于阻力矩与电动冲击扳手10电机12的输出扭矩始终保持一致，通过调用与电机12输出扭矩相关的参数作为前述参数x，则可实现通过监控参数x来识别输出轴16的负载的大小。
第一控制模块46a用于根据所述参数x符合预设条件来判定所述输出轴负载降低至等于或小于预设负载，进而改变所述电机12的转速。
其中，第一控制模块46a包括参数判断子模块462a和第一电机变速子模块464a；参数判断子模块462a监控参数x，判断参数x的值是否符合预设条件，基于前述判断结果来确认输出轴16上负载是否已降低至预设负载，若是，通过第一电机变速子模块464a改变电机转速，若否，检测模块42重新获取当前的参数x，参数判断子模块462a进而判断当前的参数x是否符合预设条件。
参图3所示，图3描述了采用电动冲击扳手10在卸除与螺栓34结合较紧密的螺母32时，供给其电机12的电流随时间的变化曲线；其中，字母t表示电机12开始工作的时间，字母i表示提供给电动冲击扳手10的电机12 的电流值。
图3中的曲线包括第一部分A、第一拐点H、第二部分B、第二拐点I、第三部分C、第三拐点J、第四部分D、第五部分E以及第六部分F。
其中第一部分A是一段上升曲线，其表示电机12刚开始启动，此时螺母32尚未给工作头14施加阻力矩，第一部分A基本可以认为是线性的；紧随着第一部分A的是第一拐点K以及后续的第二部分B，第一拐点K相对于第一部分A有一个向下倾斜的突变，第二部分B为一个下降曲线，这表示螺母32已经开始与工作头14抵紧，螺母32对工作头14施加阻力矩；在经过第二拐点I后进入基本水平的第三部分C，此时工作头14开始克服阻力矩来慢慢松开螺母32；随着时间的推移，第三部分C在第三拐点J处发生向下的跃变，并形成明显下降的第四部分D，此时螺母32已经接近被完全松开；随后进入第五部分E，该部分基本上是一段水平的直线，表明螺母32已经被完全松开，电机12处于空载状态，最后进入第六部分F，此时电机12被关停，电流i也降为0。
参图4所示，图4描述了采用电动冲击扳手10在卸除与螺栓34结合松散的螺母32时，供给其电机12的电流随时间的变化曲线；其中，字母t表示电机12开始工作的时间，字母i表示提供给电动冲击扳手10的电机12的电流值。
其中初始部分M是一段上升曲线，其表示电机12刚开始启动，此时螺母32尚未给工作头14施加阻力矩，初始部分M基本可以认为是线性的；紧随着初始部分F的后续的中间部分N，中间部分N为一个下降曲线，这表示螺母32已经开始与工作头14抵紧，螺母32对工作头14施加阻力矩；由于螺母32和螺栓34结合不紧密，工作头14很短时间内便使得螺母32和螺栓34松开，此时直接进入基本水平的部分(未标号)，该部分基本上是一段水平的直线，表明螺母32已经被完全松开，电机12处于空载状态；最后进入最终部分O，此时电机12被关停，电流i也降为0。
本实施例中，参数x为供给电动冲击扳手10中电机12的电流值，前述预设条件则为：供给电动冲击扳手10中电机12的电流值等于或小于预设电 流阈值。
结合图3和图4中的电流曲线，设定预设条件中的预设电流阈值为图3中第五部分E中电机12空载时的电流值I0，同样也是图4中最终部分0中电机12空载时的电流值I0；在作为参数x的电流值下降至电机12空载时的电流值时I0，表明螺母32已经和螺栓34松开，第一电机变速子模块464a进而改变电机12的转速。
值得注意的是：获取供给电机12的电流值可通过多次采集电流值并获得平均值的方式，从而降低电流波动导致的电流值误差，在此不做赘述。
当然，本发明的其他实施例中，预设电流阈值并不局限于前述电机12空载时的电流值I0，也可略大于或小于该空载电流值I0，此时螺母32和螺栓34也接近完全松开，螺母32对电动冲击扳手10中输出轴16的阻力矩也接近空载时的阻力矩，同样能够保证对电动冲击扳手10的控制精度。
本发明的第一构思下的第一实施例中，第一电机变速子模块464a还包括第一时刻获取单元4642a、时刻判断单元4644以及电机控制单元4646。
以电动工具电机启动时作为起算时刻，第一时刻获取单元4642a开始计时，在供给电动冲击扳手10中电机12的电流值等于或小于预设电流阈值时，第一时刻获取单元4642a生成当前的时刻并作为目标时刻T2输出至时刻判断单元4644，时刻判断单元4644内存储有预设时刻T1，根据目标时刻T2与预设时刻T1的前后，电机控制单元4646选择不同的改变电机转速的方式。
根据图3所示，由于螺母32与螺栓34结合较紧密，目标时刻T2在预设时刻T1之后，时刻判断单元4644输出对应控制指令至电机控制单元4646，进而电机控制单元4646经过第一预设时长后关停电机12；从而充分松开螺母32和螺栓34，但二者又不会脱离。
该第一预设时长可根据螺母32从当前位置至完全脱离螺栓所需行程进行设置，以在第一预设时长结束时，螺母32也仍然不会脱离螺栓34为基准；优选的，第一预设时长为10毫秒。
根据图4所示，由于螺母32与螺栓34结合较松散，目标时刻T2在预设时刻T1之前，时刻判断单元4644输出另一控制指令至电机控制单元4646， 进而电机控制单元4646即时关停电机12；从而防止过度螺母32和螺栓34而使得二者脱离。
值得注意的是：前文所述“关停电机”包括对电机的停止和刹车，在此不做赘述。
通过根据针对不同的目标时刻T2来选择不同的改变电机12转速的方式，在螺母32，使得螺母32能够最大限度的自螺栓34中转出，但又不会与螺栓34分离，降低了用户手动卸除螺母32所耗费时间，大幅提高了用户体验。
参图5所示，本发明的第一构思下所提供控制系统的第二实施例中，控制系统40与本发明的第一构思下的第一实施例相比，区别仅在于：控制系统40还包括预设模块41，该预设模块41包括指令预设子模块412、指令获取子模块414以及指令匹配子模块416。
其中，指令预设子模块412用于预设调速需求指令集，其包括多个调速需求指令，每个调速需求指令对应所述改变电机的转速的步骤的一种具体方式；指令获取子模块414用于获取用户调速需求指令；指令匹配子模块416用于根据用户调速需求指令确认所述改变电机转速的步骤的具体方式。
后续，第一电机变速子模块464a根据指令匹配子模块416所确认的方式来改变电机转速。
依据螺母自螺栓上完全卸除的行程来设定不同的变速模式，例如，将长行程设定为第一变速模式，将中、短行程设定为第二变速模式；用户根据螺母的不同行程，发出最佳的用户调速需求指令，进而获取最合适的改变电机转速的模式；随后，变速模块通过该变速方式来改变电机转速。
使得用户能够根据工况来选择改变电机转速的方式，提高了控制系统对不同工况的适应能力，从而保证了在不同工况下，螺母总能卸除到最佳位置。
优选的，可通过在电动冲击扳手上设置模式切换拨钮并在拨钮周侧标注模式图示，便于用户在使用前预先操作拨钮来选择对应的变速模式。
参图6所示，本发明在第一构思下所提供控制系统的第三实施例中，控制系统40相对于第一构思下的第一实施例，区别在于：控制系统40还包括 时钟模块43，该时钟模块43用于提供时间起点，并控制检测模块在该时间起点启动检测参数x。
其中，时间起点为电动工具开机后经过第二预设时长后的时间节点。
结合图3和图4中的电流曲线，前述时间起点可为T0时刻，T0时刻的电流i位于图3中第二部分B及图4中中间部分N；在T0时间之前，控制系统并不启动，在T0时刻，控制系统开始启动，并通过其检测模块来获取参数x。本领域技术人员可以理解的是，在T0时间之前，检测模块检测启动工作，但第一控制模块不启动接收检测模块的信号或不对检测模块传递的信号进行处理同样可以达到上述技术效果。
当然，第二预设时长也可为0，前述时间起点即为0时刻。
通过设定第二预设时长，使得控制系统启动时，工作头已经与螺母抵紧，螺母已经开始对工作头施加阻力矩，螺母即将被慢慢松开；使得控制系统能够更快的检测到参数x符合预设条件的时刻，避免了在第一部分A或初始部分M中，工作头还未与螺母抵紧，导致控制系统并无工作需求所导致的工作效率低下和能量浪费。
本发明的第一构思下所提供控制系统的第四实施例中，控制系统与第一实施例相比，区别仅在于：参数x为电机的输出扭矩值，预设条件包括：电机的输出扭矩值等于或小于预设扭矩阈值。
检测电机输出扭矩值可通过扭矩传感器来获取；并将空载时电机的输出扭矩作为预设扭矩阈值。
本发明的第一构思下所提供控制系统的第五实施例中，控制系统与第一实施例相比，区别仅在于：参数x为电机的转速值，预设条件包括：电机的转速值等于或大于预设转速阈值。
检测电机转速值可通过霍尔元件、磁钉等转速检测元件来获取；并将空载时电机的转速作为预设转速阈值。
本发明的第一构思下所提供控制系统的第六实施例中，控制系统与第一实施例相比，区别仅在于：参数x为电动工具的加速度值，该加速度值为电动工具震动所引起，预设条件包括：输出轴的加速度等于或小于预设加速度 阈值
检测输出轴加速度值可通过在工具内设置加速度传感器来获取，将空载时电机的转速作为预设转速阈值。
本发明的第一构思下所提供控制系统的第七实施例中，控制系统与前述实施例相比，控制系统中所对应的参数x和预设条件可采用前述第一至第六实施例中任一项所提及的方式；区别在于：在参数x符合预设条件所处的目标时刻T2在预设时刻T1之后时，第一电机变速子模块464a在电机运转预设圈数后关停电机。
本发明的第一构思下所提供控制系统的第八实施例中，控制系统与第一构思下的第七实施例相比，区别仅在于：在参数x符合预设条件所处的目标时刻T2在预设时刻T1之后时，第一电机变速子模块464a降低电机转速后关停电机。
本发明的第一构思下所提供控制系统的第九实施例中，控制系统与第一构思下的第七实施例相比，区别仅在于：在参数x符合预设条件所处的目标时刻T2在预设时刻T1之后时，第一电机变速子模块464a降低电机转速，通过转速降低提示用户，使得用户手动关停电机。
本发明的第一构思下所提供控制系统的第十实施例中，控制系统与第一构思下的第七实施例相比，区别仅在于：无论参数x符合预设条件所处的目标时刻T2在预设时刻T1之后还是之前，第一电机变速子模块464a均可通过使电机在连续正转和反转之间周期性切换，来提示用户，使得用户手动关停电机。
本发明的第一构思下所提供控制系统的第十一实施例中，控制系统与第一构思下的第一实施例相比，区别仅在于：预设条件为，供给电动冲击扳手10中电机12的电流值在第三预设时长内持续等于或小于预设电流阈值。预设电流阈值为图3中第五部分E中电机12空载时的电流值I0，同样也是图4中最终部分0中电机12空载时的电流值I0
本发明的第一构思下所提供控制系统的第十二实施例中，控制系统与第一构思下的第一实施例相比，区别仅在于：预设条件为，控制模块判断电流 值由大于或等于第二预设阈值，降低为小于或等于第一预设阈值。第二预设阈值大于第一预设阈值。第二预设阈值为负载值，第一预设阈值为空载值。
与现有技术相比，本发明的实施例中，控制系统能够将螺母与螺栓松开却不会使螺母和螺栓分离，用户能够根据需求手动分离螺母和螺栓，满足用户仅需松开螺母的特殊工况需求。
参图7所示，本发明的第一构思下的第一实施例中，电动工具的控制方法包括如下步骤：
步骤S20，检测表示输出轴16负载的参数x。
电动冲击扳手10在扭转螺母32对其进行紧固或卸除的过程中，由于螺母32与螺栓34之间的螺纹紧固力的存在，螺母32会通过工作头14对电动冲击扳手10的输出轴16施加一个阻力矩，在电动冲击扳手10中电机12所输出的转动扭矩克服该阻力矩时，工作头14开始紧固或卸除螺母32。
阻力矩与螺母32和螺栓34之间的螺纹紧固力成正比，在螺母32拧入螺栓34的过程中，螺母32和螺栓34之间螺纹紧固力也逐渐增加，在螺母32和螺栓34被完全拧紧时，螺纹紧固力达到峰值；反之，在电动冲击扳手10卸除螺母32的过程中，螺纹紧固力已经处在峰值，初始时刻，电动冲击扳手10的输出轴16所承受的阻力矩最大，此时需要电动冲击扳手10中电机12输出较大的转动扭矩来克服位于峰值的阻力矩，在螺母32和螺栓34脱离完全拧紧后，电动冲击扳手10的输出轴16所承受的阻力矩降低至平缓，电机12所输出的转动扭矩也同步降低至平缓。
参数x用于表示电动冲击扳手10输出轴16的负载，即用于表示电动冲击扳手10输出轴16所承受的阻力矩，由于阻力矩与电动冲击扳手10电机12的输出扭矩始终保持一致，通过调用与电机12输出扭矩相关的参数作为前述参数x，则可实现通过监控参数x来识别输出轴16的负载的大小。
随后进入步骤S40，根据所述参数x符合预设条件来判定所述输出轴负载降低至等于或小于预设负载，进而改变所述电机的转速
其中，步骤S40具体包括：
S42、监控参数x，判断参数x的值是否符合预设条件，基于前述判断结 果来确认输出轴16上负载是否已降低至预设负载，若是，执行S44步骤；
S44、改变所述电机的转速。
参图3所示，图3描述了采用电动冲击扳手10在卸除与螺栓34结合较紧密的螺母32时，供给其电机12的电流随时间的变化曲线；其中，字母t表示电机12开始工作的时间，字母i表示提供给电动冲击扳手10的电机12的电流值。
图3中的曲线包括第一部分A、第一拐点H、第二部分B、第二拐点I、第三部分C、第三拐点J、第四部分D、第五部分E以及第六部分F。
其中第一部分A是一段上升曲线，其表示电机12刚开始启动，此时螺母32尚未给工作头14施加阻力矩，第一部分A基本可以认为是线性的；紧随着第一部分A的是第一拐点K以及后续的第二部分B，第一拐点K相对于第一部分A有一个向下倾斜的突变，第二部分B为一个下降曲线，这表示螺母32已经开始与工作头14抵紧，螺母32对工作头14施加阻力矩；在经过第二拐点I后进入基本水平的第三部分C，此时工作头14开始克服阻力矩来慢慢松开螺母32；随着时间的推移，第三部分C在第三拐点J处发生向下的跃变，并形成明显下降的第四部分D，此时螺母32已经接近被完全松开；随后进入第五部分E，该部分基本上是一段水平的直线，表明螺母32已经被完全松开，电机12处于空载状态，最后进入第六部分F，此时电机12被关停，电流i也降为0。
参图4所示，图4描述了采用电动冲击扳手10在卸除与螺栓34结合松散的螺母32时，供给其电机12的电流随时间的变化曲线；其中，字母t表示电机12开始工作的时间，字母i表示提供给电动冲击扳手10的电机12的电流值。
其中初始部分M是一段上升曲线，其表示电机12刚开始启动，此时螺母32尚未给工作头14施加阻力矩，初始部分M基本可以认为是线性的；紧随着初始部分F的后续的中间部分N，中间部分N为一个下降曲线，这表示螺母32已经开始与工作头14抵紧，螺母32对工作头14施加阻力矩；由于螺母32和螺栓34结合不紧密，工作头14很短时间内便使得螺母32和螺栓 34松开，此时直接进入基本水平的部分(未标号)，该部分基本上是一段水平的直线，表明螺母32已经被完全松开，电机12处于空载状态；最后进入最终部分O，此时电机12被关停，电流i也降为0。
本发明的第一构思下的第一实施例中，参数x为供给电动冲击扳手10中电机12的电流值，前述预设条件则为：供给电动冲击扳手10中电机12的电流值等于或小于预设电流阈值。
结合图3和图4中的电流曲线，设定预设条件中的预设电流阈值为图3中第五部分E中电机12空载时的电流值I0，同样也是图4中最终部分0中电机12空载时的电流值I0；在作为参数x的电流值下降至电机12空载时的电流值I0时，表明螺母32已经和螺栓34松开，进而改变电机12的转速。
值得注意的是：获取供给电机12的电流值可通过多次采集电流值并获得平均值的方式，从而降低电流波动导致的电流值误差，在此不做赘述。
当然，本发明的其他实施例中，预设电流阈值并不局限于前述电机12空载时的电流值I0，也可略大于或小于该空载电流值I0，此时螺母32和螺栓34也接近完全松开，螺母32对电动冲击扳手10中输出轴16的阻力矩也接近空载时的阻力矩，同样能够保证对电动冲击扳手10的控制精度。
本发明的第一构思下所提供控制方法的第一实施例中，前述S44具体包括如下步骤：
S442、以电动工具电机启动时作为起算时刻，在供给电动冲击扳手10中电机12的电流值等于或小于预设电流阈值时，获取当前的时刻并作为目标时刻T2；
S444、判断目标时刻T2在预设时刻T1的之前还是之后，若在其之后，执行S446，若在其之前，执行S448；
S446、经过第一预设时长后关停电机12；
S448、即时关停电机12。
根据图3所示，由于螺母32与螺栓34结合较紧密，目标时刻T2在预设时刻T1之后，通过S446来经过第一预设时长后关停电机12；从而充分松开螺母32和螺栓34，但二者又不会脱离。
该第一预设时长可根据螺母32从当前位置至完全脱离螺栓所需行程进行设置，以在第一预设时长结束时，螺母32也仍然不会脱离螺栓34为基准；优选的，第一预设时长为10毫秒。
根据图4所示，由于螺母32与螺栓34结合较松散，目标时刻T2在预设时刻T1之前，通过S448来即时关停电机12；从而防止过度螺母32和螺栓34而使得二者脱离。
值得注意的是：前文所述“关停电机”包括对电机的停止和刹车两个步骤，在此不做赘述。
通过根据针对不同的目标时刻T2来选择不同的改变电机12转速的方式，在螺母32，使得螺母32能够最大限度的自螺栓34中转出，但又不会与螺栓34分离，降低了用户手动卸除螺母32所耗费时间，大幅提高了用户体验。
参图8所示，本发明的第一构思下所提供控制方法的第二实施例中，控制方法与本发明的其他实施例相比，区别仅在于：控制方法还包括位于步骤S20之前的步骤S10，其具体包括：
S12、预设调速需求指令集，其包括多个调速需求指令，每个调速需求指令对应所述改变电机的转速的步骤的一种具体方式；
S14、获取用户调速需求指令；
S16、根据用户调速需求指令确认所述改变电机转速的步骤的具体方式。
依据螺母自螺栓上完全卸除的行程来设定不同的变速模式，例如，将长行程设定为第一变速模式，将中、短行程设定为第二变速模式；用户根据螺母的不同行程，发出最佳的用户调速需求指令，进而获取最合适的改变电机转速的模式；随后步骤S80通过该变速方式来改变电机转速。
使得用户能够根据工况来选择改变电机转速的方式，提高了控制方法对不同工况的适应能力，从而保证了在不同工况下，螺母总能卸除到最佳位置。
优选的，可通过在电动冲击扳手上设置模式切换拨钮并在拨钮周侧标注模式图示，便于用户在使用前预先操作拨钮来选择对应的变速模式。
参图9所示，本发明的第一构思下所提供控制方法的第三实施例中，控 制方法方法相对于本发明的第一构思下所提供控制方法的第一实施例，区别在于：控制方法还包括步骤S30，该步骤S30具体包括：提供时间起点，并步骤S20在该时间起点启动。
其中，时间起点为电动工具开机后经过第二预设时长后的时间节点。
结合图3和图4中的电流曲线，前述时间起点可为T0时刻，T0时刻的电流i位于图3中第二部分B及图4中中间部分N；在T0时间之前，控制方法并不启动，在T0时刻，开始启动其步骤S20。
当然，第二预设时长也可为0，前述时间起点即为0时刻。
通过设定第二预设时长，使得控制方法启动时，工作头已经与螺母抵紧，螺母已经开始对工作头施加阻力矩，螺母即将被慢慢松开；使得控制方法能够更快的检测到参数x符合预设条件的时刻，避免了在第一部分A或初始部分M中，工作头还未与螺母抵紧，导致控制方法并无工作需求所导致的工作效率低下和能量浪费。
本发明的第一构思下所提供控制方法的第四实施例中，控制方法与本发明的第一构思下的第一实施例相比，区别仅在于：参数x为电机的输出扭矩值，预设条件包括：电机的输出扭矩值等于或小于预设扭矩阈值。
检测电机输出扭矩值可通过扭矩传感器来获取；并将空载时电机的输出扭矩作为预设扭矩阈值。
本发明的第一构思下所提供控制方法的第五实施例中，控制方法与本发明的第一构思下的第一实施例相比，区别仅在于：参数x为电机的转速值，预设条件包括：电机的转速值等于或大于预设转速阈值。
检测电机转速值可通过霍尔元件、磁钉等转速检测元件来获取；并将空载时电机的转速作为预设转速阈值。
本发明的第一构思下所提供控制方法的第六实施例中，控制方法与本发明的第一构思下的第一实施例相比，区别仅在于：参数x为电动工具的加速度值，该加速度值为电动工具震动所引起，预设条件包括：输出轴的加速度等于或小于预设加速度阈值。
检测输出轴加速度值可通过在工具内置加速度传感器来获取，将空载时 电机的转速作为预设转速阈值。
本发明的第一构思下所提供控制方法的第七实施例中，控制方法与前述实施例相比，区别仅在于：控制方法中所对应的参数x和预设条件可采用本发明的第一构思下的前述第一至第六实施例中任一项所提及的方式，区别在于：在参数x符合预设条件所处的目标时刻T2在预设时刻T1之后时，步骤S446调整为：在电机运转预设圈数后关停电机。
本发明的第一构思下所提供控制方法的第八实施例中，控制方法与本发明的第一构思下的第七实施例相比，区别仅在于：在参数x符合预设条件所处的目标时刻T2在预设时刻T1之前时，S446步骤调整为：降低电机转速后关停电机。
本发明的第一构思下所提供控制方法的第九实施例中，控制方法与本发明的第一构思下的第七实施例相比，区别仅在于：在参数x符合预设条件所处的目标时刻T2在预设时刻T1之后时，步骤S446调整为：降低电机转速。通过转速降低提示用户，使得用户手动关停电机。
本发明的第一构思下所提供控制方法的第十实施例中，控制方法与本发明的第一构思下的第七实施例相比，区别仅在于：无论参数x符合预设条件所处的目标时刻T2在预设时刻T1之后还是之前时，步骤S446和S448均可调整为：电机在连续正转和反转之间周期性切换。通过这样来提示用户，使得用户手动关停电机。
本发明的第一构思下所提供控制方法的第十一实施例中，控制方法与第一构思下的第一实施例相比，区别仅在于：预设条件为，供给电动冲击扳手10中电机12的电流值在第三预设时长内持续等于或小于预设电流阈值。预设电流阈值为图3中第五部分E中电机12空载时的电流值I0，同样也是图4中最终部分0中电机12空载时的电流值I0
本发明的第一构思下所提供控制方法的第十二实施例中，控制方法与第一构思下的第一实施例相比，区别仅在于：预设条件为，控制模块判断电流值由大于或等于第二预设阈值，降低为小于或等于第一预设阈值。第二预设阈值大于第一预设阈值。第二预设阈值为负载值，第一预设阈值为空载值。
参图10所示，本发明的第二发明构思下的第一实施例中，控制系统40包括检测模块42、第二计算模块44a以及第二控制模块46b。
检测模块42用于检测表示输出轴16负载的参数x。
电动冲击扳手10在扭转螺母32对其进行紧固或卸除的过程中，由于螺母32与螺栓34之间的螺纹紧固力的存在，螺母32会通过工作头14对电动冲击扳手10的输出轴16施加一个阻力矩，在电动冲击扳手10中电机12所输出的转动扭矩克服该阻力矩时，工作头14开始紧固或卸除螺母32。
阻力矩与螺母32和螺栓34之间的螺纹紧固力成正比，在螺母32拧入螺栓34的过程中，螺母32和螺栓34之间螺纹紧固力也逐渐增加，在螺母32和螺栓34被完全拧紧时，螺纹紧固力达到峰值；反之，在电动冲击扳手10卸除螺母32的过程中，螺纹紧固力已经处在峰值，初始时刻，电动冲击扳手10的输出轴16所承受的阻力矩最大，此时需要电动冲击扳手10中电机12输出较大的转动扭矩来克服位于峰值的阻力矩，在螺母32和螺栓34脱离完全拧紧后，电动冲击扳手10的输出轴16所承受的阻力矩降低至平缓，电机12所输出的转动扭矩也同步降低至平缓。
参数x用于表示电动冲击扳手10输出轴16的负载，即用于表示电动冲击扳手10输出轴16所承受的阻力矩，由于阻力矩与电动冲击扳手10电机12的输出扭矩始终保持一致，通过调用与电机12输出扭矩相关的参数作为前述参数x，则可实现通过监控参数x来识别输出轴16的负载的大小。
第二计算模块44a计算参数x的预设函数f(x)。
本发明的第二发明构思下的第一实施例中，该预设函数f(x)为参数x的一阶导数。
其中，第二控制模块46b包括函数判断子模块462b和第二电机变速子模块464b；函数判断子模块462b监控参数x，判断参数x的预设函数f(x)是否符合预设条件，基于前述判断结果来确认输出轴16上负载是否已降低至等于或小于预设负载，若是，通过第二电机变速子模块464b改变电机转速，若否，检测模块42重新获取当前的参数x，进而第二计算模块44a计算当前的预设函数f(x)，函数判断子模块462b进而判断当前的预设函数f(x)是否符合预设 条件。
参图3所示，图3描述了采用电动冲击扳手10在卸除与螺栓34结合较紧密的螺母32时，供给其电机12的电流随时间的变化曲线；其中，字母t表示电机12开始工作的时间，字母i表示提供给电动冲击扳手10的电机12的电流值。
图3中的曲线包括第一部分A、第一拐点H、第二部分B、第二拐点I、第三部分C、第三拐点J、第四部分D、第五部分E以及第六部分F。
其中第一部分A是一段上升曲线，其表示电机12刚开始启动，此时螺母32尚未给工作头14施加阻力矩，第一部分A基本可以认为是线性的；紧随着第一部分A的是第一拐点K以及后续的第二部分B，第一拐点K相对于第一部分A有一个向下倾斜的突变，第二部分B为一个下降曲线，这表示螺母32已经开始与工作头14抵紧，螺母32对工作头14施加阻力矩；在经过第二拐点I后进入基本水平的第三部分C，此时工作头14开始克服阻力矩来慢慢松开螺母32；随着时间的推移，第三部分C在第三拐点J处发生向下的跃变，并形成明显下降的第四部分D，此时螺母32已经接近被完全松开；随后进入第五部分E，该部分基本上是一段水平的直线，表明螺母32已经被完全松开，电机12处于空载状态，最后进入第六部分F，此时电机12被关停，电流i也降为0。
参图4所示，图4描述了采用电动冲击扳手10在卸除与螺栓34结合松散的螺母32时，供给其电机12的电流随时间的变化曲线；其中，字母t表示电机12开始工作的时间，字母i表示提供给电动冲击扳手10的电机12的电流值。
其中初始部分M是一段上升曲线，其表示电机12刚开始启动，此时螺母32尚未给工作头14施加阻力矩，初始部分M基本可以认为是线性的；紧随着初始部分F的后续的中间部分N，中间部分N为一个下降曲线，这表示螺母32已经开始与工作头14抵紧，螺母32对工作头14施加阻力矩；由于螺母32和螺栓34结合不紧密，工作头14很短时间内便使得螺母32和螺栓34松开，此时直接进入基本水平的部分(未标号)，该部分基本上是一段水 平的直线，表明螺母32已经被完全松开，电机12处于空载状态；最后进入最终部分O，此时电机12被关停，电流i也降为0。
本发明的第二发明构思下的第一实施例中，参数x为供给电动冲击扳手10中电机12的电流值，预设函数f(x)为参数x的一阶导数值，前述预设条件则为：供给电动冲击扳手10中电机12的电流值的一阶导数等于或小于预设导数阈值。
在电动工具工作的过程中，电流i会产生噪声，在电流i随时间t的关系曲线上会表现为不规则的曲线或毛刺，从而影响其一阶导数值的计算。为了避免电流i的噪声的影响，在计算一阶导数值时可以包括以下步骤，可以在多个连续时间间隔测量电流，其电流值分别为i1、i2、i3、……in。并且分别对测量得到的电流i1、i2、i3、……in对时间求一阶导数di1/dt1、di2/dt2、di3/dt3……din/dtn，并将所得的n个di/dt求得平均数；然后对其平均数的数值进行是否符合等于或小于预设导数阈值的判断。
当然，对于电流i随时间t的关系曲线上表现为不规则的曲线或毛刺，还可采用例如线性回归等多种修正方法，此为本领域普通技术人员所熟知的技术，在此不做赘述。
结合图3和图4中的电流曲线，设定预设条件中的预设导数阈值为图3中第四部分D中预设位置的电流值的一阶导数值，同样也是图4中中间部分N中预设位置的电流值的一阶导数值；显然第四部分D会比第二部分B中波形陡峭，从而能够准确识别出预设位置，在预设函数f(x)下降至等于或小于图3中第四部分D中或图4中中间部分N中预设位置的电流值的一阶导数值，表明电流急剧下降，螺母32已经和螺栓34松开，第二电机变速子模块464b进而改变电机12的转速。
本发明的第二发明构思下的第一实施例中，第二电机变速子模块464b包括第二时刻获取单元4642b、时刻判断单元4644以及电机控制单元4646。
以电动工具电机启动时作为起算时刻，第二时刻获取单元4642b开始计时，在供给电动冲击扳手10中电机12的电流值的一阶导数等于或小于预设导数阈值时，第二时刻获取单元4642b生成当前的时刻并作为目标时刻T2 输出至时刻判断单元4644，时刻判断单元4644内存储有预设时刻T1，根据目标时刻T2与预设时刻T1的前后，电机控制单元4646选择不同的改变电机转速的方式。
根据图3所示，由于螺母32与螺栓34结合较紧密，目标时刻T2在预设时刻T1之后，时刻判断单元4644输出对应控制指令至电机控制单元4646，进而电机控制单元4646经过第一预设时长后关停电机12；从而充分松开螺母32和螺栓34，但二者又不会脱离。
该第一预设时长可根据螺母32从当前位置至完全脱离螺栓所需行程进行设置，以在第一预设时长结束时，螺母32也仍然不会脱离螺栓34为基准；优选的，第一预设时长为10毫秒。
根据图4所示，由于螺母32与螺栓34结合较松散，目标时刻T2在预设时刻T1之前，时刻判断单元4644输出另一控制指令至电机控制单元4646，进而电机控制单元4646即时关停电机12；从而防止过度螺母32和螺栓34而使得二者脱离。
值得注意的是：前文所述“关停电机”包括对电机的停止和刹车，在此不做赘述。
通过根据针对不同的目标时刻T2来选择不同的改变电机12转速的方式，在螺母32，使得螺母32能够最大限度的自螺栓34中转出，但又不会与螺栓34分离，降低了用户手动卸除螺母32所耗费时间，大幅提高了用户体验。
参图11所示，本发明的第二发明构思下的第二实施例中，控制系统40与本发明的第二发明构思下的第一实施例相比，区别仅在于：控制系统40还包括预设模块41，该预设模块41包括指令预设子模块412、指令获取子模块414以及指令匹配子模块416。
其中，指令预设子模块412用于预设调速需求指令集，其包括多个调速需求指令，每个调速需求指令对应一种所述改变电机的转速步骤的一种具体方式；指令获取子模块414用于获取用户调速需求指令；指令匹配子模块416用于根据用户调速需求指令确认所述改变电机的转速的步骤的具体方式。
后续，第二电机变速子模块464b根据指令匹配子模块416所确认的方式来改变电机转速。
依据螺母自螺栓上完全卸除的行程来设定不同的变速模式，例如，将长行程设定为第一变速模式，将中、短行程设定为第二变速模式；用户根据螺母的不同行程，发出最佳的用户调速需求指令，进而获取最合适的改变电机转速的模式；随后，变速模块通过该变速方式来改变电机转速。
使得用户能够根据工况来选择改变电机转速的方式，提高了控制系统对不同工况的适应能力，从而保证了在不同工况下，螺母总能卸除到最佳位置。
优选的，可通过在电动冲击扳手上设置模式切换拨钮并在拨钮周侧标注模式图示，便于用户在使用前预先操作拨钮来选择对应的变速模式。
参图12所示，本发明的第二发明构思下的第三实施例中，控制系统40相对于本发明的第二发明构思下的第一实施例，区别在于：控制系统40还包括时钟模块43，该时钟模块43用于提供时间起点，并控制检测模块在该时间起点启动检测参数x。
其中，时间起点为电动工具开机后经过第二预设时长后的时间节点。
结合图3和图4中的电流曲线，前述时间起点可为T0时刻，T0时刻的电流i位于图3中第二部分B及图4中中间部分N；在T0时间之前，控制系统并不启动，在T0时刻，控制系统开始启动，并通过其检测模块来获取参数x。
当然，第二预设时长也可为0，前述时间起点即为0时刻。
通过设定第二预设时长，使得控制系统启动时，工作头已经与螺母抵紧，螺母已经开始对工作头施加阻力矩，螺母即将被慢慢松开；使得控制系统能够更快的检测到预设函数f(x)符合预设条件的时刻，避免了在第一部分A或初始部分M中，工作头还未与螺母抵紧，导致控制系统并无工作需求所导致的工作效率低下和能量浪费。
本发明的第二发明构思下的第四实施例中，控制系统与本发明的第二发明构思下的第一实施例相比；区别仅在于：预设函数f(x)为参数x的二阶导数，预设条件为：预设函数f(x)同样等于或小于预设导数阈值。
当然，预设函数f(x)同样可为参数x的多阶导数，在此不做赘述。
本发明的第二发明构思下的第五实施例中，控制系统与本发明的第二发明构思下的第一实施例相比，区别仅在于：参数x为电机12的输出扭矩值；预设条件为：输出扭矩的一阶导数值等于或小于预设扭矩导数阈值。
检测电机输出扭矩值可通过扭矩传感器来获取；获取预设扭矩导数阈值的方法可参考前述获取预设电流导数的方式，通过构建电机的扭矩曲线，明确电机空载时扭矩的一阶导数值，进而将其作为预设扭矩导数阈值，在此不做赘述。
本发明的第二发明构思下的第六实施例中，控制系统与本发明的第二发明构思下的前述实施例相比，控制系统中所对应的参数x和预设条件可采用本发明的第二发明构思下的前述第一至第五实施例中任一项所提及的方式，区别在于：在预设函数f(x)符合预设条件所处的目标时刻T2在预设时刻T1之后时，第二电机变速子模块464b在电机运转预设圈数后关停电机。
本发明的第二发明构思下的第七实施例中，控制系统与本发明的第二发明构思下的第六实施例相比，区别仅在于：在预设函数f(x)符合预设条件所处的目标时刻T2在预设时刻T1之后时，第二电机变速子模块464b降低电机转速后关停电机。
本发明的第二发明构思下的第八实施例中，控制系统与本发明的第二发明构思下的第六实施例相比，区别仅在于：在预设函数f(x)符合预设条件所处的目标时刻T2在预设时刻T1之后时，第二电机变速子模块464b降低电机转速，通过转速降低提示用户，使得用户手动关停电机。
本发明的第二发明构思下的第九实施例中，控制系统与本发明的第二发明构思下的第六实施例相比，区别仅在于：无论预设函数f(x)符合预设条件所处的目标时刻T2在预设时刻T1之后还是之前时，第二电机变速子模块464b均可通过使电机在连续正转和反转之间周期性切换，来提示用户，使得用户手动关停电机。
与现有技术相比，本发明的实施例中，控制系统能够将螺母与螺栓松开却不会使螺母和螺栓分离，用户能够根据需求手动分离螺母和螺栓，满足用 户仅需松开螺母的特殊工况需求。
参图13所示，本发明的第二发明构思下的第一实施例中，电动工具的控制方法包括如下步骤：
步骤S20，检测表示输出轴16负载的参数x。
电动冲击扳手10在扭转螺母32对其进行紧固或卸除的过程中，由于螺母32与螺栓34之间的螺纹紧固力的存在，螺母32会通过工作头14对电动冲击扳手10的输出轴16施加一个阻力矩，在电动冲击扳手10中电机12所输出的转动扭矩克服该阻力矩时，工作头14开始紧固或卸除螺母32。
阻力矩与螺母32和螺栓34之间的螺纹紧固力成正比，在螺母32拧入螺栓34的过程中，螺母32和螺栓34之间螺纹紧固力也逐渐增加，在螺母32和螺栓34被完全拧紧时，螺纹紧固力达到峰值；反之，在电动冲击扳手10卸除螺母32的过程中，螺纹紧固力已经处在峰值，初始时刻，电动冲击扳手10的输出轴16所承受的阻力矩最大，此时需要电动冲击扳手10中电机12输出较大的转动扭矩来克服位于峰值的阻力矩，在螺母32和螺栓34脱离完全拧紧后，电动冲击扳手10的输出轴16所承受的阻力矩降低至平缓，电机12所输出的转动扭矩也同步降低至平缓。
参数x用于表示电动冲击扳手10输出轴16的负载，即用于表示电动冲击扳手10输出轴16所承受的阻力矩，由于阻力矩与电动冲击扳手10电机12的输出扭矩始终保持一致，通过调用与电机12输出扭矩相关的参数作为前述参数x，则可实现通过监控参数x来识别输出轴16的负载的大小。
随后进入步骤S40，计算参数x的预设函数f(x)。
随后进入步骤S60，其具体包括：
S62、判断参数x的预设函数f(x)是否符合预设条件，基于前述判断结果来确认输出轴16上负载是否已降低至等于或小于预设负载，若是，执行步骤S64；若否，返回步骤S20；
S64、改变所述电机的转速。
参图3所示，图3描述了采用电动冲击扳手10在卸除与螺栓34结合较紧密的螺母32时，供给其电机12的电流随时间的变化曲线；其中，字母t 表示电机12开始工作的时间，字母i表示提供给电动冲击扳手10的电机12的电流值。
图3中的曲线包括第一部分A、第一拐点H、第二部分B、第二拐点I、第三部分C、第三拐点J、第四部分D、第五部分E以及第六部分F。
其中第一部分A是一段上升曲线，其表示电机12刚开始启动，此时螺母32尚未给工作头14施加阻力矩，第一部分A基本可以认为是线性的；紧随着第一部分A的是第一拐点K以及后续的第二部分B，第一拐点K相对于第一部分A有一个向下倾斜的突变，第二部分B为一个下降曲线，这表示螺母32已经开始与工作头14抵紧，螺母32对工作头14施加阻力矩；在经过第二拐点I后进入基本水平的第三部分C，此时工作头14开始克服阻力矩来慢慢松开螺母32；随着时间的推移，第三部分C在第三拐点J处发生向下的跃变，并形成明显下降的第四部分D，此时螺母32已经接近被完全松开；随后进入第五部分E，该部分基本上是一段水平的直线，表明螺母32已经被完全松开，电机12处于空载状态，最后进入第六部分F，此时电机12被关停，电流i也降为0。
参图4所示，图4描述了采用电动冲击扳手10在卸除与螺栓34结合松散的螺母32时，供给其电机12的电流随时间的变化曲线；其中，字母t表示电机12开始工作的时间，字母i表示提供给电动冲击扳手10的电机12的电流值。
其中初始部分M是一段上升曲线，其表示电机12刚开始启动，此时螺母32尚未给工作头14施加阻力矩，初始部分M基本可以认为是线性的；紧随着初始部分F的后续的中间部分N，中间部分N为一个下降曲线，这表示螺母32已经开始与工作头14抵紧，螺母32对工作头14施加阻力矩；由于螺母32和螺栓34结合不紧密，工作头14很短时间内便使得螺母32和螺栓34松开，此时直接进入基本水平的部分(未标号)，该部分基本上是一段水平的直线，表明螺母32已经被完全松开，电机12处于空载状态；最后进入最终部分O，此时电机12被关停，电流i也降为0。
本发明的第二发明构思下的第一实施例中，参数x为供给电动冲击扳手 10中电机12的电流值，预设函数f(x)为参数x的一阶导数值，前述预设条件则为：供给电动冲击扳手10中电机12的电流值的一阶导数值等于或小于预设导数阈值。
在电动工具工作的过程中，电流i会产生噪声，在电流i随时间t的关系曲线上会表现为不规则的曲线或毛刺，从而影响其一阶导数值的计算。为了避免电流i的噪声的影响，在计算一阶导数值时可以包括以下步骤，可以在多个连续时间间隔测量电流，其电流值分别为i1、i2、i3、……in。并且分别对测量得到的电流i1、i2、i3、……in对时间求一阶导数di1/dt1、di2/dt2、di3/dt3……din/dtn，并将所得的n个di/dt求得平均数；然后对其平均数的数值进行是否符合小于预设导数阈值的判断。
当然，对于电流i随时间t的关系曲线上表现为不规则的曲线或毛刺，还可采用例如线性回归等多种修正方法，此为本领域普通技术人员所熟知的技术，在此不做赘述。
结合图3和图4中的电流曲线，设定预设条件中的预设电流为图3中第四部分D中预设位置的电流值的一阶导数值，同样也是图4中中间部分N中预设位置的电流值的一阶导数值；显然第四部分D会比第二部分B中波形陡峭，从而能够准确识别出预设位置，便于预设函数f(x)下降至等于或小于图3中第四部分D中或图4中中间部分N中预设位置的电流值的一阶导数值，表明电流急剧下降，螺母32已经和螺栓34松开，通过步骤S64来改变电机12的转速。
本发明的第二发明构思下的第一实施例中，前述S64具体包括如下步骤：
S642、以电动工具电机启动时作为起算时刻，在供给电动冲击扳手10中电机12的电流值的一阶导数等于或小于预设导数阈值时，获取当前的时刻并作为目标时刻T2；
S644、判断目标时刻T2在预设时刻T1的之前还是之后，若在其之后，执行S646，若在其之前，执行S648；
S646、经过第一预设时长后关停电机12；
S648、即时关停电机12。
根据图3所示，由于螺母32与螺栓34结合较紧密，目标时刻T2在预设时刻T1之后，通过S646来经过第一预设时长后关停电机12；从而充分松开螺母32和螺栓34，但二者又不会脱离。
该第一预设时长可根据螺母32从当前位置至完全脱离螺栓所需行程进行设置，以在第一预设时长结束时，螺母32也仍然不会脱离螺栓34为基准；优选的，第一预设时长为10毫秒。
根据图4所示，由于螺母32与螺栓34结合较松散，目标时刻T2在预设时刻T1之前，通过S648来即时关停电机12；从而防止过度螺母32和螺栓34而使得二者脱离。
值得注意的是：前文所述“关停电机”包括对电机的停止和刹车两个步骤，在此不做赘述。
通过根据针对不同的目标时刻T2来选择不同的改变电机12转速的方式，在螺母32，使得螺母32能够最大限度的自螺栓34中转出，但又不会与螺栓34分离，降低了用户手动卸除螺母32所耗费时间，大幅提高了用户体验。
参图14所示，本发明的第二发明构思下的第二实施例中，控制方法与其他实施例相比，区别仅在于：控制方法还包括位于步骤S20之前的步骤S10，其具体包括：
S12、预设调速需求指令集，其包括多个调速需求指令，每个调速需求指令对应一种所述改变电机的转速步骤的一种具体方式；
S14、获取用户调速需求指令；
S16、根据用户调速需求指令确认所述改变电机的转速的步骤的具体方式。
依据螺母自螺栓上完全卸除的行程来设定不同的变速模式，例如，将长行程设定为第一变速模式，将中、短行程设定为第二变速模式；用户根据螺母的不同行程，发出最佳的用户调速需求指令，进而获取最合适的改变电机转速的模式；随后步骤S80通过该变速方式来改变电机转速。
使得用户能够根据工况来选择改变电机转速的方式，提高了控制方法对 不同工况的适应能力，从而保证了在不同工况下，螺母总能卸除到最佳位置。
优选的，可通过在电动冲击扳手上设置模式切换拨钮并在拨钮周侧标注模式图示，便于用户在使用前预先操作拨钮来选择对应的变速模式。
参图15所示，本发明的第二发明构思下的第三实施例中，控制方法相对于本发明的第二发明构思下的第一实施例，区别在于：控制方法还包括步骤S30，该步骤S30具体包括：提供时间起点，并步骤S20在该时间起点启动。
其中，时间起点为电动工具开机后经过第二预设时长后的时间节点。
结合图3和图4中的电流曲线，前述时间起点可为T0时刻，T0时刻的电流i位于图3中第二部分B及图4中中间部分N；在T0时间之前，控制方法并不启动，在T0时刻，开始启动其步骤S20。
当然，第二预设时长也可为0，前述时间起点即为0时刻。
通过设定第二预设时长，使得控制方法启动时，工作头已经与螺母抵紧，螺母已经开始对工作头施加阻力矩，螺母即将被慢慢松开；使得控制方法能够更快的检测到预设函数f(x)符合预设条件的时刻，避免了在第一部分A或初始部分M中，工作头还未与螺母抵紧，导致控制方法并无工作需求所导致的工作效率低下和能量浪费。
本发明的第二发明构思下的第四实施例中，控制方法与本发明的第二发明构思下的第一实施例相比；区别仅在于：预设函数f(x)为参数x的二阶导数，预设条件为：预设函数f(x)同样等于或小于预设导数阈值。
当然，预设函数f(x)同样可为参数x的多阶导数，在此不做赘述。
本发明的第二发明构思下的第五实施例中，控制方法与本发明的第二发明构思下的第一实施例相比，区别仅在于：参数x为电机12的输出扭矩值；预设条件为：输出扭矩的一阶导数值等于或小于预设扭矩导数阈值。
检测电机输出扭矩值可通过扭矩传感器来获取；获取预设扭矩导数阈值的方法可参考前述获取预设电流导数的方式，通过构建电机的扭矩曲线，明确电机空载时扭矩的一阶导数值，进而将其作为预设扭矩导数阈值，在此不做赘述。
本发明的第二发明构思下的第六实施例中，控制方法与本发明的第二发 明构思下的前述实施例相比，控制方法中所对应的参数x和预设条件可采用本发明的第二发明构思下的前述第一至第五实施例中任一项所提及的方式，区别在于：在预设函数f(x)符合预设条件所处的目标时刻T2在预设时刻T1之后时，步骤S646调整为：在电机运转预设圈数后关停电机。
本发明的第二发明构思下的第七实施例中，控制方法与本发明的第二发明构思下的第六实施例相比，区别仅在于：在预设函数f(x)符合预设条件所处的目标时刻T2在预设时刻T1之后时，步骤S646调整为：降低电机转速后关停电机。
本发明的第二发明构思下的第八实施例中，控制方法与本发明的第二发明构思下的第六实施例相比，区别仅在于：在预设函数f(x)符合预设条件所处的目标时刻T2在预设时刻T1之后时，步骤S646调整为：降低电机转速，通过转速降低提示用户，使得用户手动关停电机。
本发明的第二发明构思下的第九实施例中，控制方法与本发明的第二发明构思下的第六实施例相比，区别仅在于：在预设函数f(x)符合预设条件所处的目标时刻T2在预设时刻T1之后时，步骤S646和S648均可调整为：通过使电机在连续正转和反转之间周期性切换。来提示用户，使得用户手动关停电机。
参图16所示，本发明的第三发明构思的第一实施例中，控制系统40包括检测模块42、第三计算模块44c以及控制模块46。
检测模块42用于检测表示输出轴16负载的参数x。
电动冲击扳手10在扭转螺母32对其进行紧固或卸除的过程中，由于螺母32与螺栓34之间的螺纹紧固力的存在，螺母32会通过工作头14对电动冲击扳手10的输出轴16施加一个阻力矩，在电动冲击扳手10中电机12所输出的转动扭矩克服该阻力矩时，工作头14开始紧固或卸除螺母32。
阻力矩与螺母32和螺栓34之间的螺纹紧固力成正比，在螺母32拧入螺栓34的过程中，螺母32和螺栓34之间螺纹紧固力也逐渐增加，在螺母32和螺栓34被完全拧紧时，螺纹紧固力达到峰值；反之，在电动冲击扳手10卸除螺母32的过程中，螺纹紧固力已经处在峰值，初始时刻，电动冲击扳手 10的输出轴16所承受的阻力矩最大，此时需要电动冲击扳手10中电机12输出较大的转动扭矩来克服位于峰值的阻力矩，在螺母32和螺栓34脱离完全拧紧后，电动冲击扳手10的输出轴16所承受的阻力矩降低至平缓，电机12所输出的转动扭矩也同步降低至平缓。
参数x用于表示电动冲击扳手10输出轴16的负载，即用于表示电动冲击扳手10输出轴16所承受的阻力矩，由于阻力矩与电动冲击扳手10电机12的输出扭矩始终保持一致，通过调用与电机12输出扭矩相关的参数作为前述参数x，则可实现通过监控参数x来识别输出轴16的负载的大小。
第三计算模块44c计算参数x的预设函数f(x)，该预设函数f(x)为参数x的一阶导数。
控制模块46根据所述参数x及其预设函数f(x)符合预设条件来判定所述输出轴负载降低至等于或小于预设负载，进而改变所述电机的转速。
其中，控制模块46包括参函数判断子模块462c和第三电机变速子模块464c。
参函数判断子模块462c监控参数x，判断参数x及其预设函数f(x)是否符合预设条件，在二者均符合时，确定输出轴16上负载已降低至预设负载，若是，通过第三电机变速子模块464c改变电机转速，若否，检测模块42重新获取当前的参数x，进而第三计算模块44c计算当前的预设函数f(x)，参函数判断子模块462c进而判断当前的预设函数f(x)是否符合预设条件。
参图3所示，图3描述了采用电动冲击扳手10在卸除与螺栓34结合较紧密的螺母32时，供给其电机12的电流随时间的变化曲线；其中，字母t表示电机12开始工作的时间，字母i表示提供给电动冲击扳手10的电机12的电流值。
图3中的曲线包括第一部分A、第一拐点H、第二部分B、第二拐点I、第三部分C、第三拐点J、第四部分D、第五部分E以及第六部分F。
其中第一部分A是一段上升曲线，其表示电机12刚开始启动，此时螺母32尚未给工作头14施加阻力矩，第一部分A基本可以认为是线性的；紧随着第一部分A的是第一拐点K以及后续的第二部分B，第一拐点K相对于 第一部分A有一个向下倾斜的突变，第二部分B为一个下降曲线，这表示螺母32已经开始与工作头14抵紧，螺母32对工作头14施加阻力矩；在经过第二拐点I后进入基本水平的第三部分C，此时工作头14开始克服阻力矩来慢慢松开螺母32；随着时间的推移，第三部分C在第三拐点J处发生向下的跃变，并形成明显下降的第四部分D，此时螺母32已经接近被完全松开；随后进入第五部分E，该部分基本上是一段水平的直线，表明螺母32已经被完全松开，电机12处于空载状态，最后进入第六部分F，此时电机12被关停，电流i也降为0。
参图4所示，图4描述了采用电动冲击扳手10在卸除与螺栓34结合松散的螺母32时，供给其电机12的电流随时间的变化曲线；其中，字母t表示电机12开始工作的时间，字母i表示提供给电动冲击扳手10的电机12的电流值。
其中初始部分M是一段上升曲线，其表示电机12刚开始启动，此时螺母32尚未给工作头14施加阻力矩，初始部分M基本可以认为是线性的；紧随着初始部分F的后续的中间部分N，中间部分N为一个下降曲线，这表示螺母32已经开始与工作头14抵紧，螺母32对工作头14施加阻力矩；由于螺母32和螺栓34结合不紧密，工作头14很短时间内便使得螺母32和螺栓34松开，此时直接进入基本水平的部分(未标号)，该部分基本上是一段水平的直线，表明螺母32已经被完全松开，电机12处于空载状态；最后进入最终部分O，此时电机12被关停，电流i也降为0。
本发明的第三发明构思的第一实施例中，参数x为供给电动冲击扳手10中电机12的电流值，预设函数f(x)为参数x的一阶导数值，前述预设条件则为：供给电动冲击扳手10中电机12的电流值小于预设电流阈值，电流值的一阶导数等于或小于预设导数阈值。
在电动工具工作的过程中，电流i会产生噪声，在电流i随时间t的关系曲线上会表现为不规则的曲线或毛刺，从而影响其一阶导数值的计算。为了避免电流i的噪声的影响，在计算一阶导数值时可以包括以下步骤，可以在多个连续时间间隔测量电流，其电流值分别为i1、i2、i3、……in。并且分别 对测量得到的电流i1、i2、i3、……in对时间求一阶导数di1/dt1、di2/dt2、di3/dt3……din/dtn，并将所得的n个di/dt求得平均数；然后对其平均数的数值进行是否符合小于预设导数阈值的判断。
当然，对于电流i随时间t的关系曲线上表现为不规则的曲线或毛刺，还可采用例如线性回归等多种修正方法，此为本领域普通技术人员所熟知的技术，在此不做赘述。
值得注意的是：获取供给电机12的电流值可通过多次采集电流值并获得平均值的方式，从而降低电流波动导致的电流值误差，在此不做赘述。
结合图3和图4中的电流曲线，设定预设条件中的预设电流阈值为图3中第四部分D中预设位置的电流值，预设导数阈值为该电流的一阶导数值，同样也是图4中中间部分N中预设位置的电流值，预设导数阈值为该电流的一阶导数值；在预设函数f(x)下降至图3中第四部分D中或图4中中间部分N中预设位置的电流值的一阶导数值，表明电流急剧下降，螺母32已经和螺栓34松开，第三电机变速子模块464c进而改变电机12的转速。
通过判断参数x及其预设函数f(x)同时符合预设条件，避免了电流波动导致的误判断，提高判断的精确性。
本发明的第三发明构思的第一实施例中，第三电机变速子模块464c包括第三时刻获取单元4642c、时刻判断单元4644以及电机控制单元4646。
以电动工具电机启动作为起算时刻，第三时刻获取单元4642c开始计时，在供给电动冲击扳手10中电机12的电流及其一阶导数符合预设条件时，第三时刻获取单元4642c生成当前的时刻并作为目标时刻T2输出至时刻判断单元4644，时刻判断单元4644内存储有预设时刻T1，根据目标时刻T2与预设时刻T1的前后，电机控制单元4646选择不同的改变电机转速的方式。
根据图3所示，由于螺母32与螺栓34结合较紧密，目标时刻T2在预设时刻T1之后，时刻判断单元4644输出对应控制指令至电机控制单元4646，进而电机控制单元4646经过第一预设时长后关停电机12；从而充分松开螺母32和螺栓34，但二者又不会脱离。
该第一预设时长可根据螺母32从当前位置至完全脱离螺栓所需行程进 行设置，以在第一预设时长结束时，螺母32也仍然不会脱离螺栓34为基准；优选的，第一预设时长为10毫秒。
根据图4所示，由于螺母32与螺栓34结合较松散，目标时刻T2在预设时刻T1之前，时刻判断单元4644输出另一控制指令至电机控制单元4646，进而电机控制单元4646即时关停电机12；从而防止过度螺母32和螺栓34而使得二者脱离。
值得注意的是：前文所述“关停电机”包括对电机的停止和刹车，在此不做赘述。
通过根据针对不同的目标时刻T2来选择不同的改变电机12转速的方式，在螺母32，使得螺母32能够最大限度的自螺栓34中转出，但又不会与螺栓34分离，降低了用户手动卸除螺母32所耗费时间，大幅提高了用户体验。
参图17所示，本发明的第三发明构思的第二实施例中，控制系统40与其他实施例相比，区别仅在于：控制系统40还包括预设模块41，该预设模块41包括指令预设子模块412、指令获取子模块414以及指令匹配子模块416。
其中，指令预设子模块412用于预设调速需求指令集，其包括多个调速需求指令，每个调速需求指令对应所述改变电机的转速的步骤的一种具体方式；指令获取子模块414用于获取用户调速需求指令；指令匹配子模块416用于根据用户调速需求指令确认所述改变电机转速的步骤的具体方式。
后续，第三电机变速子模块464c根据指令匹配子模块416所确认的方式来改变电机转速。
依据螺母自螺栓上完全卸除的行程来设定不同的变速模式，例如，将长行程设定为第一变速模式，将中、短行程设定为第二变速模式；用户根据螺母的不同行程，发出最佳的用户调速需求指令，进而获取最合适的改变电机转速的模式；随后，第三电机变速子模块464c通过该变速方式来改变电机转速。
使得用户能够根据工况来选择改变电机转速的方式，提高了控制系统对 不同工况的适应能力，从而保证了在不同工况下，螺母总能卸除到最佳位置。
优选的，可通过在电动冲击扳手上设置模式切换拨钮并在拨钮周侧标注模式图示，便于用户在使用前预先操作拨钮来选择对应的变速模式。
参图18所示，本发明的第三发明构思的第三实施例中，控制系统40相对于第三发明构思的第一实施例，区别在于：控制系统40还包括时钟模块43，该时钟模块43用于提供时间起点，并控制检测模块在该时间起点启动检测参数x。
其中，时间起点为电动工具开机后经过第二预设时长后的时间节点。
结合图3和图4中的电流曲线，前述时间起点可为T0时刻，T0时刻的电流i位于图3中第二部分B及图4中中间部分N；在T0时间之前，控制系统并不启动，在T0时刻，控制系统开始启动，并通过其检测模块来获取参数x。
当然，第二预设时长也可为0，前述时间起点即为0时刻。
通过设定第二预设时长，使得控制系统启动时，工作头已经与螺母抵紧，螺母已经开始对工作头施加阻力矩，螺母即将被慢慢松开；使得控制系统能够更快的检测到预设函数f(x)符合预设条件的时刻，避免了在第一部分A或初始部分M中，工作头还未与螺母抵紧，导致控制系统并无工作需求所导致的工作效率低下和能量浪费。
本发明的第三发明构思的第四实施例中，控制系统与本发明的第三发明构思的第一实施例相比；区别仅在于：预设函数f(x)为参数x的二阶导数，预设条件为：预设函数f(x)同样等于或小于预设导数阈值。
当然，预设函数f(x)同样可为参数x的多阶导数，在此不做赘述。
本发明的第三发明构思的第五实施例中，控制系统与本发明的第三发明构思的第一实施例相比，区别仅在于：在参数x和预设函数f(x)均符合预设条件所处的目标时刻T2在预设时刻T1之后时，第三电机变速子模块464c在电机运转预设圈数后关停电机。
本发明的第三发明构思的第六实施例中，控制系统与本发明的第三发明构思的第五实施例相比，区别仅在于：在参数x和预设函数f(x)均符合预设 条件所处的目标时刻T2在预设时刻T1之后时，第三电机变速子模块464c降低电机转速后关停电机。
本发明的第三发明构思的第七实施例中，控制系统与本发明的第三发明构思的第五实施例相比，区别仅在于：在参数x和预设函数f(x)均符合预设条件所处的目标时刻T2在预设时刻T1之后时，第三电机变速子模块464c降低电机转速，通过转速降低提示用户，使得用户手动关停电机。
本发明的第三发明构思的第八实施例中，控制系统与本发明的第三发明构思的第五实施例相比，区别仅在于：无论参数x和预设函数f(x)均符合预设条件所处的目标时刻T2在预设时刻T1之后还是之前，第三电机变速子模块464c均可通过使电机在连续正转和反转之间周期性切换，来提示用户，使得用户手动关停电机。
与现有技术相比，本发明的实施例中，控制系统能够将螺母与螺栓松开却不会使螺母和螺栓分离，用户能够根据需求手动分离螺母和螺栓，满足用户仅需松开螺母的特殊工况需求。
参图19所示，本发明的第三发明构思的第一实施例中，电动工具的控制方法包括如下步骤：
步骤S20，检测表示输出轴16负载的参数x。
电动冲击扳手10在扭转螺母32对其进行紧固或卸除的过程中，由于螺母32与螺栓34之间的螺纹紧固力的存在，螺母32会通过工作头14对电动冲击扳手10的输出轴16施加一个阻力矩，在电动冲击扳手10中电机12所输出的转动扭矩克服该阻力矩时，工作头14开始紧固或卸除螺母32。
阻力矩与螺母32和螺栓34之间的螺纹紧固力成正比，在螺母32拧入螺栓34的过程中，螺母32和螺栓34之间螺纹紧固力也逐渐增加，在螺母32和螺栓34被完全拧紧时，螺纹紧固力达到峰值；反之，在电动冲击扳手10卸除螺母32的过程中，螺纹紧固力已经处在峰值，初始时刻，电动冲击扳手10的输出轴16所承受的阻力矩最大，此时需要电动冲击扳手10中电机12输出较大的转动扭矩来克服位于峰值的阻力矩，在螺母32和螺栓34脱离完全拧紧后，电动冲击扳手10的输出轴16所承受的阻力矩降低至平缓，电机 12所输出的转动扭矩也同步降低至平缓。
参数x用于表示电动冲击扳手10输出轴16的负载，即用于表示电动冲击扳手10输出轴16所承受的阻力矩，由于阻力矩与电动冲击扳手10电机12的输出扭矩始终保持一致，通过调用与电机12输出扭矩相关的参数作为前述参数x，则可实现通过监控参数x来识别输出轴16的负载的大小。
随后进入步骤S40，计算参数x的预设函数f(x)。
随后进入步骤S60，根据所述参数x及其预设函数f(x)符合预设条件来判定所述输出轴负载降低至等于或小于预设负载，进而改变所述电机的转速。
其中步骤S60具体包括：
S622、判断参数x是否符合预设条件，若是，执行步骤S624；若否，返回步骤S20；
S624、判断参数x的预设函数f(x)是否符合预设条件，若是，执行步骤S64；若否，返回步骤S20；
S64、改变所述电机的转速。
参图3所示，图3描述了采用电动冲击扳手10在卸除与螺栓34结合较紧密的螺母32时，供给其电机12的电流随时间的变化曲线；其中，字母t表示电机12开始工作的时间，字母i表示提供给电动冲击扳手10的电机12的电流值。
图3中的曲线包括第一部分A、第一拐点H、第二部分B、第二拐点I、第三部分C、第三拐点J、第四部分D、第五部分E以及第六部分F。
其中第一部分A是一段上升曲线，其表示电机12刚开始启动，此时螺母32尚未给工作头14施加阻力矩，第一部分A基本可以认为是线性的；紧随着第一部分A的是第一拐点K以及后续的第二部分B，第一拐点K相对于第一部分A有一个向下倾斜的突变，第二部分B为一个下降曲线，这表示螺母32已经开始与工作头14抵紧，螺母32对工作头14施加阻力矩；在经过第二拐点I后进入基本水平的第三部分C，此时工作头14开始克服阻力矩来慢慢松开螺母32；随着时间的推移，第三部分C在第三拐点J处发生向下的跃变，并形成明显下降的第四部分D，此时螺母32已经接近被完全松开；随 后进入第五部分E，该部分基本上是一段水平的直线，表明螺母32已经被完全松开，电机12处于空载状态，最后进入第六部分F，此时电机12被关停，电流i也降为0。
参图4所示，图4描述了采用电动冲击扳手10在卸除与螺栓34结合松散的螺母32时，供给其电机12的电流随时间的变化曲线；其中，字母t表示电机12开始工作的时间，字母i表示提供给电动冲击扳手10的电机12的电流值。
其中初始部分M是一段上升曲线，其表示电机12刚开始启动，此时螺母32尚未给工作头14施加阻力矩，初始部分M基本可以认为是线性的；紧随着初始部分F的后续的中间部分N，中间部分N为一个下降曲线，这表示螺母32已经开始与工作头14抵紧，螺母32对工作头14施加阻力矩；由于螺母32和螺栓34结合不紧密，工作头14很短时间内便使得螺母32和螺栓34松开，此时直接进入基本水平的部分(未标号)，该部分基本上是一段水平的直线，表明螺母32已经被完全松开，电机12处于空载状态；最后进入最终部分O，此时电机12被关停，电流i也降为0。
本发明的第三发明构思的第一实施例中，参数x为供给电动冲击扳手10中电机12的电流值，预设函数f(x)为参数x的一阶导数值，前述预设条件则为：供给电动冲击扳手10中电机12的电流值小于预设电流阈值，电流值的一阶导数等于或小于预设导数阈值。
在电动工具工作的过程中，电流i会产生噪声，在电流i随时间t的关系曲线上会表现为不规则的曲线或毛刺，从而影响其一阶导数值的计算。为了避免电流i的噪声的影响，在计算一阶导数值时可以包括以下步骤，可以在多个连续时间间隔测量电流，其电流值分别为i1、i2、i3、……in。并且分别对测量得到的电流i1、i2、i3、……in对时间求一阶导数di1/dt1、di2/dt2、di3/dt3……din/dtn，并将所得的n个di/dt求得平均数；然后对其平均数的数值进行是否符合小于预设导数阈值的判断。
当然，对于电流i随时间t的关系曲线上表现为不规则的曲线或毛刺，还可采用例如线性回归等多种修正方法，此为本领域普通技术人员所熟知的 技术，在此不做赘述。
值得注意的是：获取供给电机12的电流值可通过多次采集电流值并获得平均值的方式，从而降低电流波动导致的电流值误差，在此不做赘述。
结合图3和图4中的电流曲线，设定预设条件中的预设电流阈值为图3中第四部分D中预设位置的电流值的一阶导数值，同样也是图4中中间部分N中预设位置的电流值的一阶导数值；在预设函数f(x)下降至图3中第四部分D中或图4中中间部分N中预设位置的电流值的一阶导数值，表明电流急剧下降，螺母32已经和螺栓34松开，第三电机变速子模块464c进而改变电机12的转速。
通过判断参数x及其预设函数f(x)同时符合预设条件，避免了电流波动导致的误判断，提高判断的精确性。
本发明的第三发明构思的第一实施例中，前述S64具体包括如下步骤：
S642、以电动工具电机启动作为起算时刻，在供给电动冲击扳手10中电机12的电流值及其一阶导数符合预设条件时，获取当前的时刻并作为目标时刻T2；
S644、判断目标时刻T2在预设时刻T1的之前还是之后，若在其之前，执行S646，若在其之后，执行S648；
S646、经过第一预设时长后关停电机12；
S648、即时关停电机12。
根据图3所示，由于螺母32与螺栓34结合较紧密，目标时刻T2在预设时刻T1之后，通过S646来经过第一预设时长后关停电机12；从而充分松开螺母32和螺栓34，但二者又不会脱离。
该第一预设时长可根据螺母32从当前位置至完全脱离螺栓所需行程进行设置，以在第一预设时长结束时，螺母32也仍然不会脱离螺栓34为基准；优选的，第一预设时长为10毫秒。
根据图4所示，由于螺母32与螺栓34结合较松散，目标时刻T2在预设时刻T1之前，通过S648来即时关停电机12；从而防止过度螺母32和螺栓34而使得二者脱离。
值得注意的是：前文所述“关停电机”包括对电机的停止和刹车两个步骤，在此不做赘述。
通过根据针对不同的目标时刻T2来选择不同的改变电机12转速的方式，在螺母32，使得螺母32能够最大限度的自螺栓34中转出，但又不会与螺栓34分离，降低了用户手动卸除螺母32所耗费时间，大幅提高了用户体验。
参图20所示，本发明的第三发明构思的第二实施例中，控制方法与其他实施例相比，区别仅在于：控制方法还包括位于步骤S20之前的步骤S10，其具体包括：
S12、预设调速需求指令集，其包括多个调速需求指令，每个调速需求指令对应所述改变电机的转速的步骤的一种具体方式；
S14、获取用户调速需求指令；
S16、根据用户调速需求指令确认所述改变电机转速的步骤的具体方式。
依据螺母自螺栓上完全卸除的行程来设定不同的变速模式，例如，将长行程设定为第一变速模式，将中、短行程设定为第二变速模式；用户根据螺母的不同行程，发出最佳的用户调速需求指令，进而获取最合适的改变电机转速的模式；随后步骤S80通过该变速方式来改变电机转速。
使得用户能够根据工况来选择改变电机转速的方式，提高了控制方法对不同工况的适应能力，从而保证了在不同工况下，螺母总能卸除到最佳位置。
优选的，可通过在电动冲击扳手上设置模式切换拨钮并在拨钮周侧标注模式图示，便于用户在使用前预先操作拨钮来选择对应的变速模式。
参图21所示，本发明的第三发明构思的第三实施例中，控制方法方法相对于本发明的第三发明构思的第一实施例，区别在于：控制方法还包括步骤S30，该步骤S30具体包括：提供时间起点，并步骤S20在该时间起点启动。
其中，时间起点为电动工具开机后经过第二预设时长后的时间节点。
结合图3和图4中的电流曲线，前述时间起点可为T0时刻，T0时刻的电流i位于图3中第二部分B及图4中中间部分N；在T0时间之前，控制方法并不启动，在T0时刻，开始启动其步骤S20。
当然，第二预设时长也可为0，前述时间起点即为0时刻。
通过设定第二预设时长，使得控制方法启动时，工作头已经与螺母抵紧，螺母已经开始对工作头施加阻力矩，螺母即将被慢慢松开；使得控制方法能够更快的检测到预设函数f(x)符合预设条件的时刻，避免了在第一部分A或初始部分M中，工作头还未与螺母抵紧，导致控制方法并无工作需求所导致的工作效率低下和能量浪费。
本发明的第三发明构思的第四实施例中，控制方法与本发明的第三发明构思的第一实施例相比；区别仅在于：预设函数f(x)为参数x的二阶导数，预设条件为：预设函数f(x)同样等于或小于预设导数阈值。
当然，预设函数f(x)同样可为参数x的多阶导数，在此不做赘述。
本发明的第三发明构思的第五实施例中，控制方法与本发明的第三发明构思的第一实施例相比，区别仅在于：在参数x和预设函数f(x)均符合预设条件所处的目标时刻T2在预设时刻T1之前时，步骤S646调整为：在电机运转预设圈数后关停电机。
本发明的第三发明构思的第六实施例中，控制系统与本发明的第三发明构思的第五实施例相比，区别仅在于：在参数x和预设函数f(x)均符合预设条件所处的目标时刻T2在预设时刻T1之前时，步骤S646调整为：降低电机转速后关停电机。
本发明的第三发明构思的第七实施例中，控制系统与本发明的第三发明构思的第五实施例相比，区别仅在于：在参数x和预设函数f(x)均符合预设条件所处的目标时刻T2在预设时刻T1之前时，步骤S646调整为：降低电机转速，通过转速降低提示用户，使得用户手动关停电机。
本发明的第三发明构思的第八实施例中，控制系统与本发明的第三发明构思的第五实施例相比，区别仅在于：无论参数x和预设函数f(x)均符合预设条件所处的目标时刻T2在预设时刻T1之后还是之前，步骤S646和S648均可调整为：电机在连续正转和反转之间周期性切换。通过这样来提示用户，使得用户手动关停电机。
本发明还提供第四发明构思下的第一实施例，本实施例中，电动工具为 冲击扳手。冲击扳手可选择地松开或拧紧螺母。冲击扳手松开螺母的过程中，执行前述第一发明构思、第二发明构思、第三发明构思下的任意一种控制方法。
本发明还提供第四发明构思下的第二实施例，本实施例中，电动工具为冲击扳手。冲击扳手可选择地正转或反转。冲击扳手反转过程中，执行前述第一发明构思、第二发明构思、第三发明构思下的任意一种控制方法。
本发明还提供第四发明构思下的第三实施例，本实施例中，电动工具为一种冲击扳手。冲击扳手包括电机及连接电机的输出轴。冲击扳手可选择地松开或拧紧螺母。冲击扳手松开螺母的过程中，本实施例的控制方法包括以下步骤：检测表征输出轴负载的参数；判断松开条件是否满足，所述松开条件表征所述螺母由拧紧状态转换为松开状态；当所述松开条件满足时，改变电机的转速。松开条件为参数x、或参数x的函数f(x)中的至少一个符合预设条件。
本发明还提供第四发明构思下的第四实施例，本实施例中，电动工具还包括系统启动部件，系统启动部件可操作的启动控制系统，控制系统为前述第一发明构思、第二发明构思、第三发明构思下提供的任意一种控制系统。在一种情况下，电动工具为冲击扳手，冲击扳手可选择地松开或拧紧螺母，当冲击扳手执行松开螺母动作时，操作系统启动部件启动前述控制系统。在另一种情况下，电动工具为冲击扳手，冲击扳手可选择地正转或反转，当冲击扳手执行反转动作时，操作系统启动部件启动前述控制系统。
与现有技术相比，本发明的实施例中，控制方法能够将螺母与螺栓松开却不会使螺母和螺栓分离，用户能够根据需求手动分离螺母和螺栓，满足用户仅需松开螺母的特殊工况需求。
本发明还提供第五发明构思下的多种实施例。如图22所示为第五发明构思下的较佳实施例的一种电动工具，用于安装螺钉，该电动工具包括电机、工作头、电源、检测元件10’及控制模块20’。
电机启动后驱动工作头输出动力，电源用于为电机提供动力。检测元件10’用于检测表征工作头负载的参数，并输出检测信号。控制模块20’用于接 收检测元件10’输出的检测信号，根据该检测信号判断工作头的负载减小时，控制模块20’控制工作头间断地输出动力，从而改变输出模式。改变输出模式的方式还包括降低转速，停机，间断地输出动力等多种改变电机对工作头的输出方式的情况。
上述电动工具，设有检测元件10’以实时检测表征工作头负载的参数。当安装过程中出现螺钉打滑或工作头跳出螺钉头部的凹槽等使工作头负载减小的情况时，检测元件10’即可检测到表征工作头负载的参数因螺钉的安装状态改变而发生变化，进而输出检测信号至控制模块20’，控制模块20’根据检测元件10’发送的检测控制工作头间断地输出动力，从而达到监控螺钉打滑或工作头跳出螺钉头部凹槽、改变电动工具工作状态、提高螺钉安装的工作效率的目的。
由于电动工具刚开启后会产生工作参数的较大波动，而在之后趋于平稳，因此在本实施例中，启动电机后的预设时间内，控制模块20’屏蔽对检测信号的检测接收。在其他实施例中，也可采用启动电机后预设时间内检测元件10’关闭的方法进行屏蔽。
在其中一个实施例中，具体地，检测元件10’检测的表征工作头负载的参数为流经电机的电流。
螺钉处于正常安装过程中时，流经电机的电流值大致呈线性变化并处于一定范围内，而当螺钉打滑或工作头跳出螺钉头部的凹槽等负载减小的情况发生时，电流值会发生变化，控制模块20’可根据电流值的变化判断工作头的负载。
具体地，在一实施例中，当表征工作头负载的参数在一定时间段内的减小量不小于第一阈值时，控制模块20’判断工作头的负载减小。优选的，在一定时间段内参数的最大值与最小值之间的差值为正，且不小于第一阈值。更为优选的，在一定时间段内第一个时间点上的参数值与最后一个时间点上的参数值之间的差值为正，且不小于第一阈值。本实施例针对的情况是，工作头相对螺钉帽完全打滑，打滑后电动工具的负载会急剧减小，从而出现在 一定时间段内的负载参数的减小量不小于第一阈值。
当在某些场景下，工作头相对螺钉帽频繁打滑，即工作头与螺钉帽之间打滑后，工作头与螺钉帽又即刻啮合，随后工作头与螺钉帽之间再次打滑，随后工作头与螺钉帽又即刻啮合，如此循环多次。由于每次工作头与螺钉帽打滑的时间很短，随后又即刻啮合，负载会出现一个短暂的、小幅度的下降后又增加，因此负载参数在一段时间内的减小量小于第一阈值，但大于或等于第二阈值，第一阈值大于第二阈值。针对此情况，本发明提出以下两种较佳的实施例。一种较佳的实施例中，当表征工作头负载的参数在一定时间段内出现至少两次减小，且两次减小是间断出现时，控制模块20’判断工作头的负载减小。另一种实施例中，预设时间段内，当表征工作头负载的参数的减小量小于第一阈值且大于或等于第二阈值的状态出现至少两次时，控制模块20’判断工作头的负载减小。
在其中一实施例中，当至少三个相邻的时间点上的表征工作头负载的参数依次减小时，控制模块20’判断表征工作头负载的参数减小一次。在其中一实施例中，当至少三个相邻的时间点上的表征工作头负载的参数依次减小时，控制模块20’判断表征工作头负载的参数的减小量小于第一阈值且大于或等于第二阈值的状态出现一次。
在其中一实施例中，控制模块20’至少部分基于表征工作头负载的参数的一阶导数、二阶导数、或高阶导数判断工作头的负载减小。至少部分基于一阶导数判断工作头的负载减小包括但不限于以下几种情形，1)一阶导数为负，且绝对值大于或等于预设值，2)连续N个一阶导数值均为负，且绝对值大于或等于预设值，3)连续N个一阶导数值为负，且其绝对值中部分大于或等于预设值，部分小于预设值，4)连续N个一阶导数均为负，且后一个一阶导数的绝对值不小于前一个一阶导数的绝对值，即连续N个一阶导数均为负且其绝对值逐步增大，5)连续N个一阶导数均为负且其绝对值呈抛物线变化，即连续N个一阶导数均为负且其绝对值先增大后减小，6)一阶导数的函数大于或等于预设值，函数为数学学科中存在的任何可能的函数。 部分基于二阶导数或高阶导数判断工作头的负载减小的情况包括但不限于的情形同至少部分基于一阶导数判断工作头的负载减小包括但不限于的情形类似，在此不再一一列举。
在其中一实施例中，当表征工作头负载的参数的一阶导数或一阶导数的函数为负值且其绝对值不小于第二阈值时，控制模块20’判断工作头的负载减小。
在其中一实施例中，当表征工作头负载的参数的一阶导数为负值且其绝对值不小于第三阈值，且表征工作头负载的参数的数值低于第四阈值时，控制模块20’判断工作头的负载减小。
在其中一实施例中，当表征工作头负载的参数的二阶导数、二阶导数的函数、高阶导数、高阶导数的函数中的至少一个为负值且其绝对值不小于第五阈值时，控制模块20’判断工作头的负载减小。
进一步地，当控制模块20’判断工作头的负载减小时，控制模块20’通过控制电源向电机输出间断的供电电流，以使工作头间断地输出动力。间断的供电电流相当于相互间断的脉冲的供电电流。也就是说，控制模块20’相当于通过控制电源向电机输出脉冲的供电电流使工作头间断地输出动力。
在正常输出状态下，工作头持续输出动力，从而完成螺钉的安装。而在工作头间断地输出动力的状态下，可适应大扭矩的工况，较好地控制安装螺钉过程，有效的减小螺钉打滑或工作头跳出螺钉头凹槽等使工作头负载减小的状态的发生，提高安装螺钉的成功率及工作效率。
进一步地，工作头持续输出动力时，可输出两种或两种以上的扭矩，从而应对不同的工况要求。
电动工具还包括由可操控并发送调节信号的调节元件30’，操作者可对该调节元件30’进行操作控制。控制模块20’获取调节信号，并根据调节信号调整电源向电机输出的间断的供电电流。电动工具可分别以脉冲频率可调、脉冲占空比可调以及脉冲频率和脉冲占空比均可调的模式工作。从而根据实际情况选择合适的输出频率及占容比，适应不同工况的要求。
进一步地，在本实施例中，控制模块20’通过调整单次供电电流的时间宽度或相邻两次供电电流之间的时间间隔中的至少一个来调整电源向电机输出的间断的供电电流，相当于通过调整单个脉冲的供电电流的时间宽度或相邻两个脉冲的供电电流之间的时间间隔中的至少一个来调整电源向电机输出的脉冲的供电电流。
上述电动工具，可通过检测元件10’检测安装螺钉过程中流经电机的电流的变化，从而检测到工作头负载的变化，进而通过控制模块20’使工作头间断地输出动力，从而有效减小了打滑状态的发生，提高了螺钉安装的效率。
工作头包括安装于旋转头的第一工作头与第二工作头。第一工作头与第二工作头通过旋转头的旋转即可切换地连接电机，从而择一地由电机驱动。当第一工作头由电机驱动时，控制模块20’根据检测信号判断在一定时间段内第一工作头的负载的减小量不小于第一阈值时，控制工作头间断地输出动力。当第二工作头由电机驱动时，控制模块20’控制第二工作头连续输出动力。
操作者可根据需要选择第一工作头或第二工作头输出扭矩。在本实施例中，第一工作头为螺丝批，第二工作头用于实现输出扭矩恒定的钻头。在其他实施例中，第二工作头也可为电动扳手、电锤或冲击电钻的工作头。
电动工具还包括触发件及感应件。触发件设置在第一工作头和/或第二工作头上。感应件设置于电动工具主体，与触发件相对转动，用于感应触发件，并根据感应结果发送感应信号给控制模块20’，控制模块20’根据感应信号判断电机驱动的第一工作头或第二工作头。具体地，在第一工作头与第二工作头切换过程中，当感应件感应到触发件时，说明触发件随第一工作头和/或第二工作头转动至与感应件相应的位置，感应件输出电信号至检测元件10’。当第一工作头转动至与感应件相应的预定位置时，第一工作头处于工作状态，检测元件10’对表征第一工作头负载的参数进行检测。而当第二工作头处于工作状态时，检测元件10’无需对表征第一工作头及第二工作头负载的参数进行检测。
如此，该电动工具可在切换至第一工作头后，检测并自动加载对应的输出模式，完成输出模式的自动切换，提高电动工具的工作效率。
如图23所示为第五发明构思下的一种电动工具控制方法，用于螺钉的安装，包括如下步骤：
S110：检测表征工作头负载的参数。
S120：根据表征工作头负载的参数，输出检测信号。
S130：接收检测信号。
S140：根据检测信号判断工作头的负载减小时，控制工作头间断地输出动力。
检测表征工作头负载的参数的步骤之前还包括步骤：
启动电机；
启动后的预设时间内屏蔽对检测信号的接收。
在其他实施例中，检测电动工具的工作参数的步骤之间还可包括步骤：启动后的预设时间内屏蔽对表征工作头负载的参数的检测，从而提高检测的准确性。
其中，在本实施例中，表征工作头负载的参数为流经电机的电流。
在其中一实施例中，根据检测信号判断工作头的负载减小的步骤具体为：当表征工作头负载的参数在一定时间段内的减小量不小于第一阈值时，判断工作头的负载减小。
在其中一实施例中，根据检测信号判断工作头的负载减小的具体步骤为：当表征工作头负载的参数在一定时间段内出现至少两次减小，且两次减小间断出现时，控制模块20’判断所述工作头的负载减小。
在其中一实施例中，根据检测信号判断工作头的负载减小的具体步骤为：当至少三个相邻的时间点上的表征工作头负载的参数依次减小时，判断表征工作头负载的参数减小一次。
在其中一实施例中，根据检测信号判断工作头的负载减小的具体步骤为：当表征工作头负载的参数的一阶导数或一阶导数的函数为负值且其绝对值不 小于第二阈值时，控制模块20’判断工作头的负载减小。
在其中一实施例中，根据检测信号判断工作头的负载减小的具体步骤为：当表征工作头负载的参数的一阶导数为负值且其绝对值不小于第三阈值，且表征工作头负载的参数的数值低于第四阈值时，控制模块20’判断工作头的负载减小。
在其中一实施例中，根据检测信号判断工作头的负载减小的具体步骤为：当表征工作头负载的参数的二阶导数、二阶导数的函数、高阶导数或高阶导数的函数中的至少一个为负值且绝对值不小于第五阈值时，控制模块20’判断工作头的负载减小。
在螺钉的正常安装过程中，工作头为持续输出动力的正常输出状态。
当螺钉开始打滑时，控制模块20’将工作头的工作状态调整间隔输出动力的状态，从而使工作头间断地输出动力，从而改变安装方式，避免螺钉打滑及工作头跳出螺钉头部的凹槽。
控制工作头间断地输出动力的步骤具体为：通过调整单次供电电流的时间宽度或相邻两次供电电流之间的时间间隔中的至少一个来调整向电机输出的间断的供电电流。相当于通过调整单个脉冲的供电电流的时间宽度或相邻两个脉冲的供电电流之间的时间间隔中的至少一个来调整所述电源向所述电机输出的脉冲的供电电流。
上述电动工具控制方法还包括以下步骤：当工作头间断地输出动力时，关闭电动工具后重启电动工具，工作头持续输出动力。
在其他实施例中，当工作头间断地输出动力预设时间后，工作头持续输出动力。预设时间可根据操作者需要调整，以便自动恢复成正常输出模式，便于快速拧紧螺钉。
进一步地，电动工具包括可切换的第一工作头及第二工作头。第一工作头与第二工作头通过旋转头的旋转可切换地连接电机。操作者可根据需要选择第一工作头或第二工作头输出动力。在本实施例中，第一工作头用于实现螺丝批功能，第二工作头用于实现输出扭矩恒定的钻进功能。
检测电动工具的工作参数步骤之前还包括步骤：判断是否为第一工作头工作，如果是，则进行下一步检测工作参数表征工作头负载的参数的步骤。
判断是否为第一工作头的具体步骤为：感应触发件，根据感应结果发送感应信号给控制模块20’，控制模块20’根据感应信号判断由电机驱动第一工作头或第二工作头。
如此，该电动工具可根据第一工作头，自动加载不同的输出模式，根据不同的工作头完成输出模式的自动切换，提高工作效率。
上述电动工具控制方法，通过检测表征所述工作头负载的参数，即可获得螺钉打滑而导致工作头负载减小的情况，进而自动调整电动工具的工作模式，从而改变电动工具工作头的工作状态，通过间断地输出动力而减小了螺钉打滑状态的发生。进一步地，当电动工具切换至第一工作头工作时，可自动加载不同的工作模式，满足不同安装条件的要求，提高螺钉的安装效率和成功率。
应当理解，虽然本说明书按照实施方式加以描述，但并非每个实施方式仅包含一个独立的技术方案，说明书的这种叙述方式仅仅是为清楚起见，本领域技术人员应当将说明书作为一个整体，各实施方式中的技术方案也可以经适当组合，形成本领域技术人员可以理解的其他实施方式。
上文所列出的一系列的详细说明仅仅是针对本发明的可行性实施方式的具体说明，它们并非用以限制本发明的保护范围，凡未脱离本发明技艺精神所作的等效实施方式或变更均应包含在本发明的保护范围之内。

Claims (46)

  1. 一种电动工具的控制方法，其中电动工具包括电机及连接电机的输出轴，其特征在于，所述控制方法包括如下步骤：
    检测表示输出轴负载的参数x；
    根据所述参数x符合预设条件来判定所述输出轴负载降低至等于或小于预设负载，进而改变所述电机的转速。
  2. 根据权利要求1所述的控制方法，其特征在于，所述参数x为供给电机的电流值、输出轴的输出扭矩值、或电动工具的加速度值中的一个；所述预设条件包括：所述参数X等于或小于第一预设阈值。
  3. 根据权利要求1所述的控制方法，其特征在于，所述参数x为供给电机的电流值、输出轴的输出扭矩值、或电动工具的加速度值中的一个；所述预设条件包括：在第三预设时长内，所述参数X持续等于或小于第一预设阈值。
  4. 根据权利要求1所述的控制方法，其特征在于，所述参数x为供给电机的电流值、输出轴的输出扭矩值、或电动工具的加速度值中的一个；所述预设条件包括：所述参数由大于或等于第二预设阈值降低为小于或等于第一预设阈值。
  5. 根据权利要求1所述的控制方法，其特征在于，所述改变电机的转速的步骤的具体方式包括：
    以电动工具电机启动为起算时刻，获取所述参数x符合所述预设条件时的目标时刻；
    当目标时刻在预设时刻之后时，经过第一预设时长后关停电机、或在电机运转预设圈数后关停电机、或降低电机转速。
  6. 根据权利要求1所述的控制方法，其特征在于，所述改变电机的转速的步骤的具体方式包括：
    以电动工具电机启动为起算时刻，获取所述参数x符合所述预设条件时的目标时刻；
    当目标时刻在预设时刻之前时，即时关停电机。
  7. 一种电动工具的控制方法，其中电动工具包括电机及连接电机的输出轴，其特征在于，所述控制方法包括如下步骤：
    检测表示输出轴负载的参数x；
    计算所述参数x的预设函数f(x)；
    根据所述预设函数f(x)符合预设条件来判定所述输出轴负载降低至等于或小于预设负载，进而改变所述电机的转速。
  8. 根据权利要求7所述的控制方法，其特征在于，所述预设函数f(x)为参数x的N阶导数，所述N为正整数；所述预设条件为：预设函数f(x)的值等于或小于预设导数阈值。
  9. 根据权利要求7所述的控制方法，其特征在于，所述参数x为供给电机的电流值或输出轴的输出扭矩值。
  10. 根据权利要求7所述的控制方法，其特征在于，所述改变电机转速的步骤的具体方式为：
    获取所述预设函数f(x)符合所述预设条件时的目标时刻，该目标时刻自电动工具电机启动后起算；
    当目标时刻在预设时刻之后时，在经过第一预设时长后关停电机、或在电机运转预设圈数后关停电机、或降低电机转速。
  11. 根据权利要求7所述的控制方法，其特征在于，所述改变电机转速的步骤的具体方式为：
    获取所述预设函数f(x)符合所述预设条件时的目标时刻，该目标时刻自电动工具电机启动后起算；
    当目标时刻在预设时刻之前时，即时关停电机。
  12. 一种电动工具的控制方法，其中电动工具包括电机及连接电机的输出轴，其特征在于，所述控制方法包括如下步骤：
    检测表示输出轴负载的参数x；
    计算参数x的预设函数f(x)；
    根据所述参数x及其预设函数f(x)符合预设条件来判定所述输出轴负载降低至等于或小于预设负载，进而改变所述电机的转速。
  13. 根据权利要求12所述的控制方法，其特征在于，所述参数x为供给电机的电流值，所述预设函数f(x)为参数x的一阶导数值；所述预设条件包括：给电机所述供的电流值小于第一预设阈值，所述供给电机的电流值的一阶导数值为负。
  14. 根据权利要求12所述的控制方法，其特征在于，所述改变电机的转速的步骤的具体方式为：
    以电动工具电机启动为起算时刻，获取所述参数x及其预设函数f(x)符合所述预设条件时的目标时刻；
    在目标时刻在预设时刻之后时，在经过第一预设时长后关停电机、或在电机运转预设圈数后关停电机、或降低电机转速。
  15. 根据权利要求12所述的控制方法，其特征在于，所述改变电机的转速的步骤的具体方式为：
    以电动工具电机启动为起算时刻，获取所述参数x及其预设函数f(x)符合所述预设条件时的目标时刻；
    在目标时刻在预设时刻之前时，即时关停电机。
  16. 根据权利要求1、7、12中任意一项权利要求所述的控制方法，其特征在于，在所述电动工具中电机启动并经过第二预设时长后，开始检测用于表示输出轴负载的参数x。
  17. 根据权利要求1、7、12中任意一项权利要求所述的控制方法，其特征在于，所述控制方法还包括检测用于表示输出轴负载的参数x之前的如下步骤：
    预设调速需求指令集，其包括多个调速需求指令，每个调速需求指令对应所述改变电机的转速的步骤的一种具体方式；
    获取用户调速需求指令；
    根据用户调速需求指令确认所述改变电机转速的步骤的具体方式。
  18. 根据权利要求1、7、12中任意一项权利要求所述的控制方法，其特征在于，所述改变电机转速的步骤具体为：控制电机在正转和反转之间周期性切换。
  19. 根据权利要求2-4、13任意一项所述的控制方法，其特征在于，所述参数为供给电机的电流，所述第一预设阈值为所述电动工具在空载状态时的电流值。
  20. 根据权利要求1、7、12任意一项所述的控制方法，其特征在于，所述电动工具为冲击扳手，所述冲击扳手可选择地正转或反转，当所述冲击扳手执行反转动作时，所述控制方法执行根据所述参数x或参数x的函数f(x)中的至少一个符合预设条件来判定所述输出轴负载降低至等于或小于预设负载，进而改变所述电机的转速的步骤。
  21. 根据权利要求1、7、12任意一项所述的控制方法，其特征在于，所述电动工具为冲击扳手，所述冲击扳手可选择地松开或拧紧螺母，当所述冲击扳手执行松开螺母的动作时，所述控制方法执行根据所述参数x或参数x的函数f(x)中的至少一个符合预设条件来判定所述输出轴负载降低至等于或小于预设负载，进而改变所述电机的转速的步骤。
  22. 一种冲击扳手的控制方法，其特征在于，所述冲击扳手包括电机及连接电机的输出轴，所述冲击扳手可选择地松开或拧紧螺母，所述冲击扳手松开螺母的过程中，所述控制方法包括以下步骤：
    检测表征输出轴负载的参数；
    判断松开条件是否满足，所述松开条件表征所述螺母由拧紧状态转换为松开状态；
    当所述松开条件满足时，改变电机的转速。
  23. 根据权利要求22所述的控制方法，其特征在于，所述松开条件为所述参数x、或参数x的函数f(x)中的至少一个符合预设条件。
  24. 一种电动工具的控制系统，其中，电动工具包括电机及连接电机的输出轴，其特征在于，所述控制系统包括：
    检测模块，检测表示输出轴负载的参数x；
    第一控制模块，包括：
    参数判断子模块，根据所述参数x符合预设条件来判定所述输出轴负载降低至等于或小于预设负载；
    第一电机变速子模块，接收参数判断子模块的信号，进而改变所述电机的转速。
  25. 根据权利要求24所述的控制系统，其特征在于，所述参数x为供给电机的电流值、输出轴的输出扭矩值、或电动工具的加速度值的一个；所述预设条件包括：所述参数X等于或小于第一预设阈值。
  26. 根据权利要求24所述的控制系统，其特征在于，所述参数x为供给电机的电流值、输出轴的输出扭矩值、或电动工具的加速度值中的一个；所述预设条件包括：在第三预设时长内，所述参数X持续等于或小于第一预设阈值。
  27. 根据权利要求24所述的控制系统，其特征在于，所述参数x为供给电机的电流值、输出轴的输出扭矩值、或电动工具的加速度值中的一个；所述预设条件包括：所述参数由大于或等于第二预设阈值降低为小于或等于第一预设阈值。
  28. 根据权利要求24所述的控制系统，其特征在于，所述第一电机变速子模块包括：
    第一时刻获取单元，以电动工具电机启动为起算时刻，获取所述参数x符合所述预设条件时的目标时刻；
    时刻判断单元，判断目标时刻是否在预设时刻之后；
    电机控制单元，当目标时刻在预设时刻之后时，经过第一预设时长后关停电机、或控制电机运转预设圈数后关停电机、或降低电机转速。
  29. 根据权利要求24所述的控制系统，其特征在于，所述第一电机变速子模块包括：
    第一时刻获取单元，以电动工具电机启动为起算时刻，获取所述参数x 符合所述预设条件时的目标时刻；
    时刻判断单元，判断目标时刻是否在预设时刻之前；
    电机控制单元，当目标时刻在预设时刻之前时，即时关停电机。
  30. 一种电动工具的控制系统，其中，电动工具包括电机及连接电机的输出轴，其特征在于，所述控制系统包括：
    检测模块，检测用于表示输出轴负载的参数x；
    第二计算模块，计算所述参数x的预设函数f(x)；
    第二控制模块，包括：
    函数判断子模块，根据所述预设函数f(x)符合预设条件来判定所述输出轴负载降低至等于或小于预设负载；
    第二电机变速子模块，接收函数判断子模块的信号，进而改变所述电机的转速。
  31. 根据权利要求30所述的控制系统，其特征在于，所述预设函数f(x)为参数x的N阶导数，所述N为正整数；所述预设条件为：预设函数f(x)的值等于或小于预设导数阈值。
  32. 根据权利要求30所述的控制系统，其特征在于，所述参数x为供给电机的电流值或输出轴的扭矩值。
  33. 根据权利要求30所述的控制系统，其特征在于，所述第二电机变速子模块包括：
    第二时刻获取单元，以电动工具电机启动为起算时刻，获取所述函数f(x)符合所述预设条件时的目标时刻；
    时刻判断单元，判断目标时刻是否在预设时刻之后；
    电机控制单元，当目标时刻在预设时刻之后时，经过第一预设时长后关停电机、或控制电机运转预设圈数后关停电机、或降低电机转速。
  34. 根据权利要求30所述的控制系统，其特征在于，所述第二电机变速子模块包括：
    第二时刻获取单元，以电动工具电机启动为起算时刻，获取所述函数f(x) 符合所述预设条件时的目标时刻；
    时刻判断单元，判断目标时刻是否在预设时刻之前；
    电机控制单元，当目标时刻在预设时刻之前时，即时关停电机。
  35. 一种电动工具的控制系统，其中，电动工具包括电机及连接电机的输出轴，其特征在于，所述控制系统包括：
    检测模块，检测用于表示输出轴负载的参数x；
    第三计算模块，计算参数x的预设函数f(x)；
    第三控制模块，包括：
    参函数判断子模块，根据所述参数x及其预设函数f(x)符合预设条件来判定所述输出轴负载降低至等于或小于预设负载；
    第三电机变速子模块，接收参函数判断子模块的信号，进而改变所述电机的转速。
  36. 根据权利要求35所述的控制系统，其特征在于，所述参数x为供给电机的电流值，所述预设函数f(x)为参数x的一阶导数值；所述预设条件包括：所述供给电机的电流值小于第一预设阈值，所述供给电机的电流值的一阶导数值为负。
  37. 根据权利要求35所述的控制系统，其特征在于，所述第三电机变速子模块包括：
    第三时刻获取单元，以电动工具电机启动为起算时刻，获取所述参数x和函数f(x)符合所述预设条件时的目标时刻；
    时刻判断单元，判断目标时刻是否在预设时刻之后；
    电机控制单元，当目标时刻在预设时刻之后时，经过第一预设时长后关停电机、或控制电机运转预设圈数后关停电机、或降低电机转速。
  38. 根据权利要求35所述的控制系统，其特征在于，所述第三电机变速子模块包括：
    第三时刻获取单元，以电动工具电机启动为起算时刻，获取所述参数x和函数f(x)符合所述预设条件时的目标时刻；
    时刻判断单元，判断目标时刻是否在预设时刻之前；
    电机控制单元，当目标时刻在预设时刻之前时，即时关停电机。
  39. 根据权利要求24、30、35中任意一项权利要求所述的控制系统，其特征在于，在所述电动工具中电机启动并经过第二预设时长后，检测模块开始检测用于表示输出轴负载的参数x。
  40. 根据权利要求24、30、35中任意一项权利要求所述的控制系统，其特征在于，所述控制系统还包括预设模块，所述预设模块包括：
    指令预设子模块，用于预设调速需求指令集，其包括多个调速需求指令，每个调速需求指令对应所述改变电机的转速的步骤的一种具体方式；
    指令获取子模块，用于获取用户调速需求指令；
    指令匹配子模块，用于根据用户调速需求指令确认所述改变电机转速的步骤的具体方式。
  41. 根据权利要求24、30、35中任意一项权利要求所述的控制系统，其特征在于，所述电机变速子模块控制电机在正转和反转之间周期性切换。
  42. 根据权利要求25-27、36任意一项所述的控制系统，其特征在于，所述参数为供给电机的电流，所述第一预设阈值为所述电动工具在空载状态时的电流值。
  43. 一种电动工具，其特征在于，所述电动工具包括：
    电源；
    电机，获取电源的电力以提供旋转动力；
    输出轴，获取电机的旋转动力并输出；
    根据权利要求24、30、35中任一项所述的控制系统，所述控制系统与电机和电源电性连接。
  44. 根据权利要求43所述电动工具，其特征在于，所述电动工具还包括：系统启动部件，其用于可操作的启动所述控制系统。
  45. 根据权利要求43所述电动工具，其特征在于，所述电动工具为冲击扳手，所述冲击扳手可选择地松开或拧紧螺母，当所述冲击扳手执行松开螺 母动作时，操作所述系统启动部件启动所述控制系统。
  46. 根据权利要求43所述电动工具，其特征在于，所述电动工具为冲击扳手，所述冲击扳手可选择地正转或反转，当所述冲击扳手执行反转动作时，操作所述系统启动部件启动所述控制系统。
PCT/CN2015/088893 2014-09-02 2015-09-02 电动工具的控制方法及控制系统、电动工具 Ceased WO2016034136A1 (zh)

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