WO2020108569A1 - 链锯、电动工具以及电动工具的控制方法 - Google Patents

链锯、电动工具以及电动工具的控制方法 Download PDF

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Publication number
WO2020108569A1
WO2020108569A1 PCT/CN2019/121639 CN2019121639W WO2020108569A1 WO 2020108569 A1 WO2020108569 A1 WO 2020108569A1 CN 2019121639 W CN2019121639 W CN 2019121639W WO 2020108569 A1 WO2020108569 A1 WO 2020108569A1
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WO
WIPO (PCT)
Prior art keywords
brushless motor
main body
controller
braking mode
angular velocity
Prior art date
Application number
PCT/CN2019/121639
Other languages
English (en)
French (fr)
Inventor
赵金标
王宏伟
Original Assignee
南京德朔实业有限公司
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 CN201811433127.7A external-priority patent/CN111245312A/zh
Priority claimed from CN201811433129.6A external-priority patent/CN111226626B/zh
Application filed by 南京德朔实业有限公司 filed Critical 南京德朔实业有限公司
Priority to EP19890514.3A priority Critical patent/EP3872978B1/en
Publication of WO2020108569A1 publication Critical patent/WO2020108569A1/zh
Priority to US17/328,565 priority patent/US20210276217A1/en

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Classifications

    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
    • H02P3/00—Arrangements for stopping or slowing electric motors, generators, or dynamo-electric converters
    • H02P3/06—Arrangements for stopping or slowing electric motors, generators, or dynamo-electric converters for stopping or slowing an individual dynamo-electric motor or dynamo-electric converter
    • H02P3/18—Arrangements for stopping or slowing electric motors, generators, or dynamo-electric converters for stopping or slowing an individual dynamo-electric motor or dynamo-electric converter for stopping or slowing an ac motor
    • H02P3/22—Arrangements for stopping or slowing electric motors, generators, or dynamo-electric converters for stopping or slowing an individual dynamo-electric motor or dynamo-electric converter for stopping or slowing an ac motor by short-circuit or resistive braking
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23D—PLANING; SLOTTING; SHEARING; BROACHING; SAWING; FILING; SCRAPING; LIKE OPERATIONS FOR WORKING METAL BY REMOVING MATERIAL, NOT OTHERWISE PROVIDED FOR
    • B23D59/00—Accessories specially designed for sawing machines or sawing devices
    • B23D59/001—Measuring or control devices, e.g. for automatic control of work feed pressure on band saw blade
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
    • B25F—COMBINATION OR MULTI-PURPOSE TOOLS NOT OTHERWISE PROVIDED FOR; DETAILS OR COMPONENTS OF PORTABLE POWER-DRIVEN TOOLS NOT PARTICULARLY RELATED TO THE OPERATIONS PERFORMED AND NOT OTHERWISE PROVIDED FOR
    • B25F5/00—Details or components of portable power-driven tools not particularly related to the operations performed and not otherwise provided for
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B27—WORKING OR PRESERVING WOOD OR SIMILAR MATERIAL; NAILING OR STAPLING MACHINES IN GENERAL
    • B27B—SAWS FOR WOOD OR SIMILAR MATERIAL; COMPONENTS OR ACCESSORIES THEREFOR
    • B27B17/00—Chain saws; Equipment therefor
    • B27B17/02—Chain saws equipped with guide bar
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B27—WORKING OR PRESERVING WOOD OR SIMILAR MATERIAL; NAILING OR STAPLING MACHINES IN GENERAL
    • B27B—SAWS FOR WOOD OR SIMILAR MATERIAL; COMPONENTS OR ACCESSORIES THEREFOR
    • B27B17/00—Chain saws; Equipment therefor
    • B27B17/08—Drives or gearings; Devices for swivelling or tilting the chain saw
    • B27B17/083—Devices for arresting movement of the saw chain
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
    • H02P6/00—Arrangements for controlling synchronous motors or other dynamo-electric motors using electronic commutation dependent on the rotor position; Electronic commutators therefor
    • H02P6/24—Arrangements for stopping
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
    • H02P6/00—Arrangements for controlling synchronous motors or other dynamo-electric motors using electronic commutation dependent on the rotor position; Electronic commutators therefor
    • H02P6/14—Electronic commutators
    • H02P6/16—Circuit arrangements for detecting position
    • H02P6/18—Circuit arrangements for detecting position without separate position detecting elements

Definitions

  • the present application relates to the field of power tools, for example, to a chain saw, a power tool, and a control method of the power tool.
  • a chain saw is a garden tool that uses a power device to drive the lateral movement of the L-shaped blades on the saw chain to cut wood or branches.
  • Some related power tools help reduce the occurrence of backlash through improved mechanical structure.
  • the operator cannot adjust the power tool in time (for example, stop the power tool), which may cause an accident of a safety accident.
  • the present application provides a chain saw, a power tool, and a control method of a power tool, which can detect backlash and brake in time after detecting backlash.
  • the present application provides a chain saw, including: a working part including a guide plate and a saw chain; a main body part capable of mounting the working part; a brushless motor for driving the working part to work, the brushless motor has a drive Mode and braking mode; the brushless motor includes a rotor and a winding; a power supply device is used to provide electrical energy to the brushless motor; a drive circuit is connected to the power supply device and the winding to connect the power supply The electric energy of the device is loaded to the winding of the brushless motor; the controller is connected to the drive circuit to control the drive circuit; the motion detection device is connected in association with the main body or the working part for Detecting the movement change of the main body part or the working part in at least one direction; the controller is configured to: the movement change amount of the main body part or the working part in at least one direction exceeds a preset threshold At this time, the driving circuit is controlled to make the brushless motor enter the braking mode.
  • the controller is configured to: the value of the angular velocity at which the main body portion or the working member rotates in at least one direction is greater than the first preset angular velocity threshold and less than the second preset angular velocity threshold, and the When the value of the angular displacement of the main body part or the working member rotating in at least one direction is greater than a preset angular displacement threshold, the driving circuit is controlled to cause the brushless motor to enter the braking mode.
  • the controller is configured to control the drive circuit to control the brushless motor when the value of the angular velocity of the main body part or the working member rotating in at least one direction is greater than a preset angular velocity threshold Enter the braking mode.
  • the motion detection device includes: a gyro sensor for detecting at least one of the angular velocity and angular displacement of the main body portion or the working member rotating in at least one direction.
  • the brushless motor has a driving mode; the controller is configured to: in the braking mode, control the driving circuit according to the position of the rotor so that the current direction of the winding and the The current direction in drive mode is reversed.
  • the brushless motor has multiple commutation positions, and the area between each commutation position is a sector; the controller is configured to: in the braking mode, according to the rotor Each sector controls the drive circuit to reverse the current of the winding in each sector.
  • the controller is configured to: after the brushless motor enters the braking mode, after the duration of the braking mode reaches a preset duration, control the driving circuit to The winding of the brushless motor is short-circuited.
  • the controller is configured to: after the brushless motor enters the braking mode, after the speed of the rotor of the brushless motor drops to a preset speed threshold, control the drive The circuit short-circuits the windings of the brushless motor.
  • the braking mode includes a first braking process and a second braking process
  • the controller is configured to: during the first braking process, control the drive according to the position of the rotor The circuit makes the current direction of the winding of the brushless motor opposite to the current direction in the driving mode; during the second braking process, the driving circuit is controlled so that the winding of the brushless motor Short.
  • a position detection device for detecting the position of the rotor of the brushless motor.
  • the present application also provides an electric tool, including: a working part for realizing the function of the electric tool; a main body part capable of installing a working part; a brushless motor for driving the working part to work, the brushless
  • the motor has a driving mode and a braking mode;
  • the brushless motor includes a rotor and a winding;
  • a power supply device is used to provide electrical energy to the brushless motor;
  • a drive circuit is connected to the power supply device and the winding to connect the The power of the power supply device is loaded to the winding of the brushless motor;
  • the controller is connected to the drive circuit to control the drive circuit;
  • the motion detection device is connected in association with the main body or the working part For detecting the change in motion of the main body or the working member in at least one direction; the controller is configured to: the amount of change in motion of the main body or the working member in at least one direction exceeds When the threshold is preset, the driving circuit is controlled to make the brushless motor enter the braking mode.
  • the controller is configured to: when the value of the angular velocity of the main body part or the working component rotating in at least one direction is greater than the first preset angular velocity threshold and less than the second preset angular velocity threshold, and When the value of the angular displacement of the main body part or the working member rotating in at least one direction is greater than a preset angular displacement threshold, the driving circuit is controlled to cause the brushless motor to enter the braking mode.
  • the controller is configured to control the drive circuit to control the brushless motor when the value of the angular velocity of the main body part or the working member rotating in at least one direction is greater than a preset angular velocity threshold Enter braking mode.
  • the motion detection device includes: a gyro sensor for detecting at least one of the angular velocity and angular displacement of the main body portion or the working member rotating in at least one direction.
  • the controller is configured to: in the braking mode, control the drive circuit according to the position of the rotor so that the current direction of the winding of the brushless motor and the current during driving The direction is opposite.
  • the controller is configured to: after the brushless motor enters the braking mode, when the duration of the braking mode reaches a preset duration, control the driving circuit so that the The winding of the brush motor is short-circuited.
  • the controller is configured to: after the brushless motor enters the braking mode, when the rotation speed of the rotor of the brushless motor drops to a preset rotation speed threshold, control the drive The circuit short-circuits the windings of the brushless motor.
  • the present application also provides a control method of an electric tool.
  • the electric tool includes: a working part for realizing the function of the electric tool; a main body part capable of installing the working part; a brushless motor for driving a power tool
  • the working part works, the brushless motor has a driving mode and a braking mode, the brushless motor includes a rotor and a winding; a motion detection device, associated with the main body or the working part, is used to detect the Movement of the main body or the working member in at least one direction;
  • the control method includes: acquiring at least one of the angular velocity and angular displacement of the main body or the working member in at least one direction; Whether at least one of the angular velocity and angular displacement of the main body or the working component in at least one direction exceeds a preset threshold; in determining the angular velocity and angular displacement of the main body or the working component in at least one direction After at least one exceeds the preset threshold, the power tool is put into the braking mode
  • the drive circuit is controlled to reverse the current of the winding of the brushless motor according to the position of the rotor.
  • the winding of the brushless motor is short-circuited.
  • the winding of the brushless motor is short-circuited.
  • the technical solution provided by the present application can avoid the defects of the traditional recoil detection method that uses an accelerometer to measure acceleration, which is sensitive to vibration; the motion detection device of the present application is used to detect the angular velocity or angular displacement of the main body part or working part of the power tool,
  • the implementation method of backlash detection and later data processing are simpler, the vibration interference is small, and the detection is more accurate; the power tool of the present application can realize quick braking faster, thereby effectively avoiding the occurrence of safety accidents caused by backlash.
  • FIG. 1 is a perspective view of the overall structure of an electric tool as an embodiment
  • FIG. 2 is a partial cross-sectional view of the power tool shown in FIG. 1;
  • FIG. 3 is a schematic diagram of the power tool shown in FIG. 1 when kickback occurs;
  • FIG. 4 is a circuit diagram of a circuit system as an embodiment
  • FIG. 5 is a relationship diagram of the Hall signal, the conduction switch, the conduction winding and the sector where the rotor is located in the driving state of the circuit system shown in FIG. 4;
  • FIG. 6 is a flowchart of a control method of an electric tool as an embodiment when detecting kickback
  • FIG. 7 is a relationship diagram of the Hall signal, the on switch, the on winding, and the sector where the rotor is in the braking state of the circuit system of FIG. 4;
  • FIG. 8 is a flowchart of a control method of an electric power tool during braking as an embodiment
  • FIG. 9 is a flowchart of a control method of a power tool according to another embodiment during braking.
  • the power tools 10 of the present application include, but are not limited to, screwdrivers, electric drills, angle grinders, benders, pruning machines, chain saws, and other power tools that can backlash, as long as these power tools 10 can adopt the substance of the technical solutions disclosed below It can fall within the scope of protection of this application.
  • the power tool 10 uses a chain saw as an example.
  • the power tool 10 includes a working part 15 and a main body 20.
  • the working part includes a guide plate 151 and a saw chain 152.
  • the main body includes a housing 11, and the front end of the main body is configured. To be able to install the working member 15.
  • the power tool 10 includes a housing 11, a front handle 12 and a main handle 13 provided on the housing 11, a switch trigger 14 provided on the main handle 13, and a working part 15 for realizing a specific function ⁇ 16 ⁇ And power supply device 16.
  • the content of the present application can also be applied to other power tools, such as electric circular saws, electric drills, impact drills, high-power angle grinders, and other hand-held power tools that may cause backlash.
  • the working part 15 of the electric tool 10 includes the guide plate 151 and the saw chain 152 described above.
  • the saw chain 152 surrounds the edge of the guide plate 151 and can be cyclically guided along the guide plate 151 under the drive of a driving mechanism (not shown).
  • One end of the guide plate 151 is supported on the housing 11 and the other end extends along the longitudinal direction of the housing 11 ⁇ 11 ⁇ The housing 11.
  • the switch trigger 14 is operably triggered by the user, and the switch trigger 14 is associated with the main switch 18 which is electrically connected in the main circuit of the power tool 10.
  • the switch trigger 14 is actuated, the main switch 18 associated with the switch trigger 14 is actuated accordingly, allowing or prohibiting electrical connection of circuit components across the main switch 18.
  • the power tool 10 further includes a power supply device 16 for powering the power tool.
  • the power tool 10 is powered by a DC power source. More specifically, the power tool 10 is powered by a battery pack, and the power supply device includes a battery pack. In some other embodiments, the power tool 10 is powered by an AC power supply, and the AC power supply may be 120V or 220V AC mains power.
  • the power supply device 16 includes a power conversion circuit that cooperates with some power conversion circuits connected to AC power. (Not shown), the alternating current is converted into electrical energy that can be used by the electric tool 10 through a hardware circuit to rectify, filter, divide voltage, and reduce the alternating current signal output by the power supply.
  • the power tool 10 is powered by a battery pack, and the voltage output by the battery pack is changed by a specific power supply circuit (for example, a DC-DC conversion chip) to output a power supply voltage suitable for a controller or the like.
  • a specific power supply circuit for example, a DC-DC conversion chip
  • the battery pack as a DC power supply, it is necessary to cooperate with the corresponding power supply circuit.
  • the housing 11 also includes an automatic lubrication system (not shown).
  • an automatic lubrication system (not shown).
  • the specific structure of the front handle 12, the main handle 13, the working part 15, and the lubrication system are common knowledge and will not be detailed here. description.
  • FIG. 2 is a cross-sectional view of the power tool 10 shown in FIG. 1 with the working part 15 and the battery pack removed.
  • the housing 11 is provided with a brushless motor 17 for driving the movement of the saw chain 152, a main switch 18 controlled by a switch trigger 14, the main switch 18 is used to control the opening and closing of the power tool 10 during normal use, and a circuit board 19,
  • the circuit board 19 is provided with electronic components, circuit components, and the like.
  • a kickback or kickback event For a chain saw, when a saw chain of an athlete near the front end attachment of the guide plate 151 contacts, for example, a log or a branch, the chain saw may rapidly move upward or backward, which is often referred to as a kickback or kickback event.
  • the main body part 20 or working part 15 of the chain saw will rotate around the Z axis in the XY plane, and the guide plate 151 and the saw chain 152 will move in the direction of the operator, which may cause Operator injury may even cause serious injury or death to the operator.
  • the kickback needs to be detected promptly and accurately, and the brake can be quickly braked after the kickback is detected to avoid safety to the greatest extent possible. The accident happened.
  • the operation of the power tool 10 also needs to rely on electronic components or circuit components provided on the circuit board 19. 4, the electronic components or circuit components of the power tool 10 may specifically include the following controller 41 and drive circuit 42.
  • the power tool 10 further includes a motion detection device 43 and a rotor position detection device 44.
  • the controller 41, the drive circuit 42, the motion detection device 43, the position detection device 44, and the brushless motor 17 are all enclosed by the housing 11.
  • the controller 41, the drive circuit 42, the motion detection device 43, the rotor position detection device 44, and the brushless motor 17, the battery pack 16, and the like are electrically connected to constitute a circuit system of the power tool 10.
  • the brushless motor 17 outputs power to drive the working component 15 to work.
  • the brushless motor 17 includes a stator, a rotor 171, a motor shaft and windings.
  • the motor shaft is driven by the rotor 171 of the brushless motor 17.
  • the rotor 171 rotates relative to the stator, and the stator has an iron core and a stator winding wound around the stator core.
  • the brushless motor 17 has three-phase windings, which are a first-phase winding A, a second-phase winding B, and a third-phase winding C, respectively.
  • the driving circuit 42 is electrically connected to the brushless motor 17 to drive the rotor 171 of the brushless motor 17 to operate.
  • the drive circuit 42 is specifically electrically connected to the three-phase winding of the brushless motor 17 and drives the brushless motor 17 to operate.
  • the driving circuit 22 specifically includes a switching element.
  • the driving circuit 42 shown in FIG. 4 includes switching elements VT1, VT2, VT3, VT4, VT5, and VT6.
  • the switching elements VT1, VT2, VT3, VT4, VT5, and VT6 form a three-phase circuit.
  • Bridge in which VT1, VT3, VT5 are the upper bridge switch, VT2, VT4, VT6 are the lower bridge switch, the switching element can choose field effect tube, IGBT transistor and so on.
  • each switching element is electrically connected to the drive signal output terminal of the controller 41, and the drain or source of each switching element is electrically connected to the winding of the brushless motor 17.
  • the switching element changes the on state according to the drive signal output by the controller 41, thereby changing the voltage state of the battery pack 16 loaded on the winding of the brushless motor 17, and drives the brushless motor 17 to operate.
  • the drive circuit 42 In order to rotate the brushless motor 17, the drive circuit 42 has multiple driving states. In one driving state, the stator winding of the motor generates a magnetic field, and the controller 41 is configured to output a corresponding drive according to the rotation position of the rotor of the brushless motor 17. The signal is sent to the driving circuit 42 to switch the driving state of the driving circuit 42, thereby changing the state of the voltage applied to the winding of the brushless motor 17, generating an alternating magnetic field to drive the rotor to rotate, and thereby driving the brushless motor 17.
  • the power tool 10 further includes a position detection device 44 for detecting the position of the rotor 171 of the brushless motor 17.
  • the position detection device 44 may be sensorless or sensory.
  • the position detection device 44 includes a position sensor, for example, three Hall sensors (not shown), which are arranged along the circumferential direction of the rotor 171 of the brushless motor 17, and the Hall sensor detects the position of the rotor The information is input to the position detection device 44.
  • the position detection device 44 converts the input rotor position into rotor position information that can communicate with the controller 41 through logic processing, and inputs it to the controller 41.
  • the signal of the Hall sensor changes, and the output signal of the position detection device 44 also changes accordingly.
  • the output signal of the position detection device 44 When the rotor turns into the preset range, the output signal of the position detection device 44 is defined as 1, and when the rotor turns out of the preset range, the output signal of the position detection device 44 is defined as 0.
  • the three Hall sensors are separated from each other by a physical angle of 120°.
  • the three Hall sensors will generate a position signal including six signal combinations so that the position detection device 44 outputs a position signal including one of the six signal combinations. If they are arranged in the order in which the Hall sensors are placed, six different signal combinations 100, 110, 010, 011, 001, and 101 appear. In this way, the position detection device 44 can output one of the above six position signals, and the position of the rotor 171 can be known based on the position detection signal output by the position detection device 44.
  • the brushless motor 17 With three-phase windings, it has six driving states in one energizing cycle corresponding to the output signal generated by the above scheme, so when the output signal of the position detection device 44 changes, the brushless motor 17 17 can perform a commutation.
  • the brushless motor 17 is commutated every time the rotor 171 rotates through 60°, and the interval from one commutation to the next commutation of the brushless motor 17 is defined as one sector. It can also be said that the brushless motor 17 has a plurality of commutation positions, and the area between each commutation position is a sector.
  • the driving state of the driving circuit 42 is shown below with the correspondingly connected terminals of the driving circuit.
  • the driving state is indicated by AB
  • the controller 42 controls the driving
  • the switching element of the circuit 42 connects the first-phase winding A to the negative power supply 16b and the second-phase winding B to the positive power supply 16a.
  • This driving state is indicated by BA.
  • the driving method shown in this way is also applicable to the triangular connection scheme of the windings. .
  • the switching of the driving state may also be referred to simply as the commutation operation of the brushless motor.
  • the position detection device 44 does not include a position sensor, but obtains the rotor position indirectly by performing corresponding calculations based on the back electromotive force signal or the bus current of the motor and/or the terminal voltage of the motor, which will not be repeated here.
  • Those skilled in the art can easily know based on the expertise in the field.
  • the controller 41 is electrically connected to the driving circuit 42 for outputting a driving signal to control the driving circuit 42 to work.
  • the controller 41 uses a dedicated control chip (eg, MCU, Microcontroller Unit).
  • the control chip internally includes a storage unit for storing braking programs and driver programs.
  • the controller 41 can control the circuit state of the entire power tool 10 and realize various electronic functions, such as soft start, braking, battery protection, and the like.
  • the electric power tool 10 further includes a motion detection device 43 that is associated with the main body 20 or the working part 15 of the electric power tool 10 for detecting movement changes, such as movement, of the main body 20 or the working part 15 in at least one direction Volume, moving speed, rotating angular velocity, rotating angular displacement.
  • a motion detection device 43 that is associated with the main body 20 or the working part 15 of the electric power tool 10 for detecting movement changes, such as movement, of the main body 20 or the working part 15 in at least one direction Volume, moving speed, rotating angular velocity, rotating angular displacement.
  • the output end of the motion detection device 43 is connected to the controller 41, which sends the detected result to the controller 41, when the motion detection device 43 detects the amount of change in motion of the main body 20 or the working member 15 in at least one direction
  • the controller 41 controls the drive circuit 42 to make the brushless motor 17 enter the braking mode.
  • the controller 41 uses the motion detection device 43 to detect the amount of change in movement of the main body portion 20 or the working part of the power tool 10 in at least one direction, and compares it with a preset threshold value to determine whether the power tool 10 has reacted. If the preset threshold is exceeded, it is determined that the power tool 10 has a backlash, so that the controller 41 controls the power tool 10 to enter the braking mode to perform emergency braking to avoid a safety accident.
  • the motion detection device 43 may specifically include a gyro sensor.
  • the gyro sensor is a MEMS9 (microelectromechanical system) multi-axis gyro sensor, which is used to detect the main body 20 or the working part 15 At least one of angular velocity and angular displacement of rotation in at least one direction. For example, at least one of the angular velocity and angular displacement of the main body 20 or the working member 15 rotating around the Z axis is detected.
  • MEMS gyroscope sensors are small and can be easily incorporated into existing circuits, and output voltages that the sensors can scale.
  • the gyro sensor may be installed on the main body 20 of the power tool 10.
  • the front handle is close to the center of rotation when kickback occurs.
  • the gyro The instrument sensor can be installed at various positions away from the front handle 12, such as the front end of the guide plate 151, and the main handle 13. The selection of the installation position of the gyro sensor should ensure that at least one of the angular velocity and the angular displacement of the rotation of the main body 20 or the working part 15 of the power tool 10 can be accurately detected, which is not limited herein.
  • the gyro sensor measures the angular velocity at which the power tool 10 moves, and integrates the angular velocity to obtain the angular displacement.
  • the controller 41 controls the drive circuit 42 to put the brushless motor 17 into the braking mode.
  • the gyro sensor is used to detect the angular velocity and angular displacement of the main body 20 or the working member 15 rotating in at least one direction
  • the controller 41 is configured to: the value of the angular velocity is greater than the first preset angular velocity threshold and When it is less than the second preset angular velocity threshold and the value of the angular displacement is greater than the preset angular displacement threshold, the drive circuit 42 is controlled to make the brushless motor 17 enter the braking mode.
  • the value of the angular velocity W at which the gyro sensor detects the rotation of the power tool 10 is greater than or equal to the first preset angular velocity threshold TW1 and less than or equal to the second preset angular velocity threshold TW2, and the rotational angular displacement ⁇ is greater than or equal to
  • the controller 41 controls the switching element of the drive circuit 42 to make the brushless motor 17 enter the braking mode.
  • the gyro sensor is used to detect the angular velocity of the main body 20 or the working member 15 rotating in at least one direction; the controller 41 is configured to control the driving circuit when the value of the angular velocity is greater than a preset angular velocity threshold 42 Puts the brushless motor 17 into the braking mode.
  • a preset angular velocity threshold 42 Puts the brushless motor 17 into the braking mode.
  • the controller 41 controls the switching element of the drive circuit 42 to make the brushless motor 17 enter the braking mode.
  • Step S60 power on the power tool
  • Step S61 Obtain the rotation angular velocity W collected by the gyro sensor
  • the gyro sensor detects the rotational angular velocity W of the main body 20 or the working member 15 about the Z axis.
  • Step S62 Integrate the rotation angular velocity W to obtain the angular displacement ⁇ ;
  • the controller 41 performs an integral operation on the obtained rotational angular velocity W to obtain the angular displacement ⁇ of the main body 20 or the working member 15 rotating around the Z axis.
  • Step S63 compare and determine whether the rotational angular velocity W is less than the first preset angular velocity threshold TW1, if yes, go to step S61, if not, go to step S64;
  • the controller 41 first compares the obtained angular velocity W with the first preset angular velocity threshold TW1, and if the angular velocity W is less than the first preset angular velocity threshold TW1, it proceeds to step S61, and continues to acquire the angular velocity, if not, it proceeds to step S64.
  • Step S64 compare and determine whether the rotational angular velocity W is less than the second preset angular velocity threshold TW2, if yes, go to step S65, if not go to step S66;
  • the angular velocity W is compared with the second preset angular velocity threshold TW2. If the angular velocity W is less than the second preset angular velocity threshold TW2, then go to step S65 Judging the magnitude of the displacement ⁇ , if the angular velocity W is greater than or equal to the second preset angular velocity threshold TW2, then go to step S66 and directly enter the braking mode.
  • Step S65 compare and determine whether the angular displacement ⁇ is less than the preset angular displacement T ⁇ , if yes, go to step S61; if not, go to step S66;
  • Step S66 Enter the braking mode.
  • the motion detection device 43 using the gyro sensor detects the angular velocity and angular displacement of the rotation of the main body 20 or the working part 15 of the power tool 10 to detect whether the power tool 10 has a backlash, avoiding the traditional acceleration measurement
  • the defect of the recoil detection method is sensitive to vibration.
  • the implementation of the recoil detection in this embodiment and the later data processing are simpler, the vibration interference is small, and the recoil detection is more accurate.
  • the first preset angular velocity threshold TW1, the second preset angular velocity threshold TW2, and the preset angular displacement T ⁇ are selected by the user according to actual conditions, so that the detection result can accurately identify the occurrence of impact, which is not limited herein.
  • the power tool 10 includes a driving mode and a braking mode.
  • the controller 41 executes a driving program and controls the switching element of the driving circuit 42 to operate the rotor 171 of the brushless motor 17.
  • the controller 41 executes a braking program, and controls the switching element of the drive circuit 42 to make the brushless motor 17 enter the braking mode.
  • the power tool 10 After detecting the occurrence of kickback, the power tool 10 enters the emergency braking mode to avoid a safety accident.
  • the short-circuit braking method is usually used for braking.
  • the motor windings are short-circuited, that is, all upper bridge switch elements or lower bridges of the drive circuit 42 are controlled by the controller 41
  • the switching elements are all turned on, and the ends of each phase winding connected to the neutral point are connected to each other, thereby short-circuiting each phase winding.
  • using the resistance of the winding itself consumes energy. Because the resistance of the winding is small, the energy consumption is fast, there is a certain danger, and the motor may be burned.
  • the controller 41 controls the driving circuit 42 according to the position of the rotor 171 so that the current direction of the winding is opposite to the current direction in the driving mode.
  • the controller 41 controls the switching element of the driving circuit 42 to short-circuit the windings of the brushless motor 17 .
  • the switching element of the drive circuit 42 is controlled so that the The winding is shorted.
  • the linear speed of the chain saw is greater than or equal to 15 m/s.
  • the braking mode includes a first braking process and a second braking process.
  • the controller 41 controls the switching element of the drive circuit 42 according to the position of the rotor 171, so that the current of each sector of each phase winding during braking is opposite to the current of the winding in the driving mode
  • the controller 41 controls the electric tool 10 to switch to the second braking process.
  • the second braking process uses a short-circuit braking method to brake the brushless motor 17.
  • the controller 41 controls the drive circuit 42 to short-circuit the windings of the brushless motor 17 for braking.
  • the preset condition includes: the duration of the first braking process reaches a preset duration or the rotation speed of the rotor 171 of the brushless motor 17 drops to a preset rotation speed threshold or less than a preset rotation speed threshold.
  • the position detection device 44 includes a Hall sensor, and the brushless motor is a Y-type connection.
  • the Hall sensor detects the position of the rotor 171 in real time.
  • the position detection device 44 outputs 010. In the braking mode, this At this time, the driving circuit 42 should be controlled to turn on the BA phase.
  • the controller 41 controls the switching elements VT3 and VT4 to turn on, and the remaining switching elements are turned off, so that the currents of the A-phase and B-phase windings are opposite to the current in the driving mode;
  • the position detection device 44 outputs a signal 011, which is switched to CA conduction, correspondingly, the controller 41 controls the switching elements VT4 and VT5 to turn on, the remaining switching elements are turned off, and so on until After the rotation speed of the rotor 171 drops to the preset rotation speed threshold or after the duration of the first braking process reaches the preset duration, it switches to the second braking process.
  • the current of the windings of all sectors can be reversed to the current in the driving mode to achieve rapid braking, or it can be less than the current of the windings of multiple sectors of all sectors.
  • the current direction in the driving mode is opposite.
  • the braking time can be adjusted by changing the number of sectors in the first braking process that are opposite to the current direction in the driving mode. The more the number, the shorter the braking time and the less the number. , The longer the braking time.
  • the controller 41 controls the on-off state of the switching element of the drive circuit 42 to realize the braking of the brushless motor 17, and by changing the on-off switch, the winding
  • the current in the driving process is opposite to the current in the driving mode, so that the brushless motor 17 runs in reverse order.
  • the duration of the braking process can be achieved through software.
  • the braking time can be adjusted, but it is impossible to judge when the motor stops rotating.
  • the speed of the brushless motor 17 or the speed of the rotor 171 decreases to reach the preset speed threshold or the duration of the first braking process reaches the preset duration, it switches to the second
  • the short-circuit braking during the braking process prevents the rotor 171 of the brushless motor from continuing to rotate in the opposite direction.
  • the braking time during the first braking process is adjustable, enabling rapid braking.
  • the controller 41 controls the upper bridge switching elements VT1, VT2, and VT3 to be all turned on or the lower bridge switching elements VT4, VT6, and VT2 to be all turned on, so that the three-phase windings are short-circuited, and the brushless motor 17
  • the inertial rotation will generate a reverse torque, causing the brushless motor 17 to stop quickly. Since the second braking process adopts short-circuit braking, the windings of the brushless motor 17 are all short-circuited, and the kinetic energy of the brushless motor 17 is consumed on the windings.
  • This embodiment adopts that in the first braking process, switching to the second braking process after the preset condition is reached, the brushless motor 17 can be quickly stopped and the braking process is more safe and reliable.
  • the method includes the following steps:
  • the controller 41 judges that the power tool 10 has kickback according to the rotation angular velocity W collected by the gyro sensor and the rotation angular displacement ⁇ obtained by integrating the rotation angular velocity W, it enters the braking mode.
  • the controller 41 first starts the first braking process and executes the first braking procedure
  • the position detection device 44 detects the position of the rotor in real time.
  • the position of the rotor is detected by the Hall sensor.
  • the position sensor When the rotor rotates to a preset range that can be used by the Hall sensor, the position sensor is in a signal state. The position sensor switches to another signal state when turning out of the preset range.
  • the signal of the Hall sensor is output to the position detection device 44, and the position detection device 44 converts the input rotor position into a rotor position information that can communicate with the controller 41 through logic processing, and then inputs it to the controller 41. Signal to determine the current sector position of the rotor.
  • the controller 41 controls the drive circuit 42 according to the relationship table (table 2) of the rotor sector position, the Hall signal, and the on-off switching element during the first braking process previously stored in the memory according to the current sector position of the rotor
  • the corresponding switching element of is turned on or off to reverse the current of the winding in each sector and the current in the driving mode, thereby generating a reverse torque to brake the brushless motor 17.
  • step S84 Determine whether the duration of the first braking process reaches the preset duration, if yes, go to step S85, if no, go to step S83;
  • the power tool 10 includes a timer or timer.
  • the timer or timer may be built in the controller 41 or may be external to the controller 41.
  • the timer or timer is used to determine the first braking process. duration.
  • the timer or timer starts to work, and when the duration of the first braking process reaches a preset duration, it proceeds to step S84, if not, it proceeds to step S83 , Then continue to maintain the first braking process.
  • the controller 41 When it is determined that the duration of the first braking process reaches a preset duration, the controller 41 starts the second braking process.
  • the controller 41 controls all lower bridge switching elements or all upper bridge switching elements of the drive circuit 42 to be turned on, so that the three-phase winding is short-circuited, and the kinetic energy of the brushless motor 17 is consumed on the winding. Since the resistance on the winding is relatively small, it will be generated With a large short-circuit current, the kinetic energy of the brushless motor 17 is quickly released quickly, so that the brushless motor 17 instantaneously generates a great braking torque, which can achieve the effect of rapid braking.
  • the method includes the following steps:
  • the controller 41 judges that the power tool 10 has kickback according to the rotation angular velocity W collected by the gyro sensor and the rotation angular displacement ⁇ obtained by integrating the rotation angular velocity W, it enters the braking mode.
  • the controller 41 first starts the first braking process and executes the first braking procedure
  • the position detection device 44 detects the position of the rotor in real time.
  • the position of the rotor is detected by the Hall sensor.
  • the position sensor When the rotor rotates to a preset range that can be used by the Hall sensor, the position sensor is in a signal state. The position sensor switches to another signal state when turning out of the preset range.
  • the signal of the Hall sensor is output to the position detection device 44, and the position detection device 44 converts the input rotor position into a rotor position information that can communicate with the controller 41 through logic processing, and then inputs it to the controller 41. Signal to determine the current sector position of the rotor.
  • the controller 41 controls the drive circuit 42 according to the relationship table (table 2) of the rotor sector position, the Hall signal, and the on-off switching element during the first braking process previously stored in the memory according to the current sector position of the rotor
  • the corresponding switching element of is turned on or off, so that the current of the winding in each sector is opposite to the current during driving, thereby generating a reverse torque that brakes the brushless motor 17.
  • step S94 determine whether the rotor speed has dropped to the specified value, if yes, go to step S95, if no, go to step S93;
  • the power tool 10 includes a speed detection device for detecting the rotation speed of the rotor 171 or the motor shaft speed, and sends the detected result to the controller 41.
  • the speed detection device may be built in the controller 41 or may be externally controlled 41, the controller 41 compares the rotation speed detected by the speed detection device with a preset specified value to determine whether the rotation speed of the rotor 171 has fallen to a preset rotation speed threshold value, if yes, go to step S95, if no, then go To step S93, the brake control is continued.
  • the controller 41 switches to the second braking process.
  • the controller 41 controls all the lower bridge switching elements or the upper bridge switching elements of the drive circuit 42 to be turned on, short-circuiting the three-phase winding, and the kinetic energy of the brushless motor 17 is consumed on the winding. With a large short-circuit current, the kinetic energy of the brushless motor 17 is quickly released quickly, so that the instantaneous brushless motor 17 generates a great braking torque, which can achieve the effect of rapid braking.
  • the braking time of this scheme is shorter than that of the short-circuit braking mode, which meets the safety requirements of braking time less than 0.12s, which can effectively avoid the safety accidents caused by recoil.
  • the working component 15 is directly driven by the brushless motor 17.
  • a gear transmission assembly (not shown) may also be provided connected to the brushless motor 17 .

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Abstract

一种链锯和电动工具（10），包括：工作部件（15）、主体部（20）、无刷电机（17）、供电装置（16）、驱动电路（42）、控制器（41）、运动检测装置（43），其中，运动检测装置（43）与主体部（20）或工作部件（15）关联连接，用于检测主体部（20）或工作部件（15）在至少一个方向上的运动变化；控制器（41）被配置为：在主体部（20）或工作部件（15）在至少一个方向上的运动变化量超过预设阈值时，控制驱动电路（42）使无刷电机（17）进入制动模式。

Description

链锯、电动工具以及电动工具的控制方法
本申请要求在2018年11月28日提交中国专利局、申请号分别为201811433127.7和201811433129.6的两个中国专利申请的优先权，两个申请的全部内容通过引用结合在本申请中。
技术领域
本申请涉及电动工具领域，例如涉及一种链锯、电动工具以及电动工具的控制方法。
背景技术
目前电动工具广泛应用于家庭、园林等领域，而无刷电机由于其力矩大、功率高的特点被越来越多的应用到电动工具中，以满足使用者对高效节能的电动工具的使用需要。尤其是电动园林工具，如链锯，链锯是一种通过动力装置带动锯链上交错的L形刀片横向运动来进行切割木材或树枝的园林工具。链锯在正常操作时，当锯齿卡在被锯物体中时，电机的持续旋转会引起链锯的向上摆动，使得链锯朝向使用者面部的方向倒转即反冲，引发事故，因此需要在发生危险状况时及时制动以阻止链条进行移动。
相关的一些电动工具通过改进的机械结构帮助减少反冲的发生。但是，由于不能了解到何时发生反冲，操作者不能及时地调整电动工具(例如，停止电动工具)，可能导致安全事故的事故。
发明内容
本申请提供一种链锯、电动工具以及电动工具的控制方法，能够检测反冲并且能在检测到反冲后及时制动。
本申请提供了一种链锯，包括：工作部件，包括导板和锯链；主体部，能够安装所述工作部件；无刷电机，用于驱动所述工作部件工作，所述无刷电机具有驱动模式和制动模式；所述无刷电机包括转子和绕组；供电装置，用于为所述无刷电机提供电能；驱动电路，与所述供电装置和所述绕组连接，用于将所述供电装置的电能加载至所述无刷电机的绕组；控制器，与所述驱动电路连接，用于控制所述驱动电路；运动检测装置，与所述主体部或所述工作部件关联连接，用于检测所述主体部或所述工作部件在至少一个方向上的运动变化；所述控制器被配置为：在所述主体部或所述工作部件在至少一个方向上的运动变化量超过预设阈值时，控制所述驱动电路使所述无刷电机进入所述制动模式。
可选地，所述控制器被配置为：在所述主体部或所述工作部件在至少一个方向上旋转的角速度的值大于第一预设角速度阈值且小于第二预设角速度阈值，且所述主体部或所述工作部件在至少一个方向上旋转的角位移的值大于预设角位移阈值时，控制所述驱动电路使所述无刷电机进入所述制动模式。
可选地，所述控制器被配置为：在所述主体部或所述工作部件在至少一个方向上旋转的角速度的值大于预设角速度阈值时，控制所述驱动电路使所述无刷电机进入所述制动模式。
可选地，所述运动检测装置包括：一个陀螺仪传感器，用于检测所述主体部或所述工作部件在至少一个方向上旋转的角速度和角位移中的至少一个。
可选地，所述无刷电机具有驱动模式；所述控制器被配置为：在所述制动模式中，根据所述转子的位置控制所述驱动电路使所述绕组的电流方向与所述驱动模式中的电流方向相反。
可选地，所述无刷电机具有多个换相位置，各个换相位置之间的区域为一个扇区；所述控制器被配置为：在所述制动模式中，根据所述转子所处扇区控制所述驱动电路使所述绕组在每个扇区的电流反向。
可选地，所述控制器被配置为：在所述无刷电机进入所述制动模式后，制动模式在所述制动模式的持续时间达到预设时长后，控制所述驱动电路使所述无刷电机的所述绕组短接。
可选地，所述控制器被配置为：在所述无刷电机进入所述制动模式后，在所述无刷电机的所述转子的转速下降至预设转速阈值后，控制所述驱动电路使所述无刷电机的所述绕组短接。
可选地，所述制动模式包括第一制动过程和第二制动过程，所述控制器被配置为：在所述第一制动过程中，根据所述转子的位置控制所述驱动电路使所述无刷电机的所述绕组的电流方向与所述驱动模式中的电流方向相反；在所述第二制动过程中，控制所述驱动电路使所述无刷电机的所述绕组短接。
可选地，还包括：位置检测装置，用于检测所述无刷电机的所述转子的位置。
本申请还提供了一种电动工具，包括：工作部件，用于实现所述电动工具的功能；主体部，能够安装工作部件；无刷电机，用于驱动所述工作部件工作，所述无刷电机具有驱动模式和制动模式；所述无刷电机包括转子和绕组；供电装置，用于为所述无刷电机提供电能；驱动电路，与所述供电装置和所述绕组连接，用于将所述供电装置的电能加载至所述无刷电机的绕组；控制器，与所述驱动电路连接，用于控制所述驱动电路；运动检测装置，与所述主体部或所述工作部件关联连接，用于检测所述主体部或所述工作部件在至少一个方向上的运动变化；所述控制器被配置为：在所述主体部或所述工作部件在至少一个方向上的运动变化量超过预设阈值时，控制所述驱动电路使所述无刷电机进入所述制动模式。
可选地，所述控制器被配置为：当所述主体部或所述工作部件在至少一个方向上旋转的角速度的值大于第一预设角速度阈值且小于第二预设角速度阈值，且所述主体部或所述工作部件在至少一个方向上旋转的角位移的值大于预设角位移阈值时，控制所述驱动电路使所述无刷电机进入所述制动模式。
可选地，所述控制器被配置为：当所述主体部或所述工作部件在至少一个方向上旋转的角速度的值大于预设角速度阈值时，控制所述驱动电路使所述无刷电机进入制动模式。
可选地，所述运动检测装置包括：一个陀螺仪传感器，用于检测所述主体部或所述工作部件在至少一个方向上旋转的角速度和角位移中的至少一个。
可选地，所述控制器被配置为：在所述制动模式中，根据所述转子的位置控制所述驱动电路使所述无刷电机的所述绕组的电流方向与驱动过程中的电流方向相反。
可选地，所述控制器被配置为：在所述无刷电机进入所述制动模式后，当所述制动模式的持续时间达到预设时长后，控制所述驱动电路使所述无刷电机的所述绕组短接。
可选地，所述控制器被配置为：在所述无刷电机进入所述制动模式后，当所述无刷电机的所述转子的转速下降至预设转速阈值后，控制所述驱动电路使所述无刷电机的所述绕组短接。
本申请还提供了一种电动工具的控制方法，所述电动工具包括：工作部件，用于实现所述电动工具的功能；主体部，能够安装所述工作部件；无刷电机，用于驱动所述工作部件工作，所述无刷电机具有驱动模式和制动模式，所述无刷电机包括转子和绕组；运动检测装置，与所述主体部或所述工作部件关联连接，用于检测所述主体部或所述工作部件在至少一个方向上的运动变化；所述控制方法包括：获取所述主体部或所述工作部件在至少一个方向上的角速度和角位移中的至少一个；判断所述主体部或所述工作部件在至少一个方向上的角速度和角位移中的至少一个是否超过预设阈值；在判断所述主体部或所述工作部件在至少一个方向上的角速度和角位移中的至少一个超过所述预设阈值后，使所述电动工具进入所述制动模式。
可选地，在所述制动模式中，根据所述转子的位置控制所述驱动电路使所述无刷电机的所述绕组的电流反向。
可选地，在所述制动模式的持续时间达到预设时长后，使所述无刷电机的所述绕组的短接。
可选地，在所述转子的转速下降至预设转速阈值后，使所述无刷电机的所述绕组短接。
本申请提供的技术方案，可避免采用加速度计测加速度的传统反冲检测方法对振动敏感的缺陷；采用本申请的运动检测装置来检测电动工具的主体部或工作部件的角速度或角位移的，反冲检测实现方式和后期数据处理更简单，振动干扰小，检测更准确；本申请的电动工具能够更快地实现快速制动，从而有效避免反冲发生带来安全事故。
附图说明
图1是作为一种实施方式的电动工具的整体结构的立体图；
图2是图1所示的电动工具的局部剖视图；
图3是图1所示的电动工具发生反冲时的示意图；
图4是作为一种实施方式的电路系统的电路图；
图5是图4所示电路系统在驱动状态下霍尔信号、导通开关、导通绕组以及转子所处扇区的关系图；
图6是作为一种实施方式的电动工具在检测反冲时的控制方法的流程图；
图7是图4电路系统在制动状态下霍尔信号、导通开关、导通绕组以及转子所处扇区的关系图；
图8是作为一种实施方式的电动工具在制动时的控制方法的流程图；
图9是作为另一种实施方式的电动工具在制动时的控制方法的流程图。
具体实施方式
以下结合附图和具体实施例对本申请作具体的介绍。
本申请的电动工具10包括但不限于螺丝批、电钻、角磨、曲、修枝机、链锯等会发生反冲的电动工具，只要这些电动工具10能够采用以下披露的技术方案的实质内容即可落在本申请的保护范围 内。
作为一种实施方式，电动工具10以链锯为例，电动工具10包括工作部件15和主体部20，工作部件包括导板151和锯链152，主体部包括壳体11，主体部的前端被配置为能够安装所述工作部件15。
参照图1和图2，电动工具10包括壳体11、设置在壳体11上的前把手12及主把手13、设置在主把手13上的开关扳机14、用于实现具体功能的工作部件15以及供电装置16。可以理解的是，本申请的内容也可以应用在其他应用在电动工具中，如电圆锯、电钻、冲击钻、大功率角磨机等可能发生反冲的手持式电动工具。
电动工具10的工作部件15包括上述导板151及锯链152。锯链152环绕在导板151边缘且能够在驱动机构(图未示)的驱动下沿导板151循环地导引，导板151一端支承于壳体11上，另一端沿壳体11纵长方向延伸出壳体11。
开关扳机14可操作地被用户触发，开关扳机14与主开关18关联连接，主开关18电连接在电动工具10的主电路中。当开关扳机14被触动，与开关扳机14关联连接的主开关18相应地被触动，允许或禁止主开关18两端的电路部件电连接。
电动工具10还包括供装置16，用于为电动工具提供动力。在一些实施例中，电动工具10使用直流电源供电，更具体地，电动工具10使用电池包供电，供电装置包括电池包。在另一些实施例中，电动工具10使用交流电源供电，所述的交流电源可以为120V或220V的交流市电，供电装置16包括电源转换电路，该交流电源配合一些连接于交流电的电源转换电路(未示出)，所述交流电通过硬件电路对电源输出的交流信号进行整流、滤波、分压、降压等处理转换成可供所述电动工具10使用的电能。在本实施例中，电动工具10使用电池包供电，电池包输出的电压通过具体的电源电路(例如，DC-DC转换芯片)进行电压变化，输出适合控制器等的供电电压。对于作为直流电源的电池包而言，需要进行配合相应的电源电路。
壳体11内还包括自动润滑系统(图未示)，对本领域普通技术人员来说，前把手12、主把手13、工作部件15、以及润滑系统等具体结构都属于公知常识，这里不再详细描述。
图2为图1所示的电动工具10去掉工作部件15和电池包的电动工具10的剖视图。壳体11内设置有用于驱动锯链152运动的无刷电机17、由开关扳机14控制的主开关18，主开关18用于控制电动工具10正常使用时的开启与关闭，以及电路板19，电路板19上设置有电子元器件或电路部件等。
对链锯而言，当靠近导板151的前端附件的运动者的锯链接触到诸如原木或树枝时可能出现链锯快速向上或向后运动，也就是常说的反冲或回踢事件。参照图3，当链锯发生反冲时，链锯的主体部20或工作部件15在XY平面内会绕Z轴转动，导板151和锯链152会朝向操作者的方向移动，这样可能会导致操作者受伤，甚至会造成导致操作者重伤或死亡，为了防止反冲事件发生，需要及时且准确地检测到反冲，并且在检测到反冲发生后能迅速制动，以最大程度的避免安全事故的发生。
上述电动工具10的运行还需要依靠设置于电路板19上的电子元器件或电路部件。参照图4，上 述电动工具10的电子元器件或电路部件具体可包括如下控制器41、驱动电路42。在本实施例中，电动工具10还包括运动检测装置43、转子位置检测装置44。上述控制器41、驱动电路42、运动检测装置43、位置检测装置44，以及无刷电机17均由壳体11封闭。上述控制器41、驱动电路42、运动检测装置43、转子位置检测装置44，以及无刷电机17、电池包16等电性连接构成电动工具10的电路系统。
无刷电机17输出动力驱动所述工作部件15工作。所述无刷电机17包括定子、转子171、电机轴和绕组，电机轴由无刷电机17的转子171驱动。转子171相对定子旋转，定子具有铁芯及绕设定与定子铁心上的定子绕组。本实施例中，所述无刷电机17具有三相绕组，分别为第一相绕组A、第二相绕组B、第三相绕组C。
驱动电路42电连接至所述无刷电机17，用以驱动所述无刷电机17的转子171运转。驱动电路42具体与无刷电机17的三相绕组电连接，驱动无刷电机17运转。驱动电路22具体包括有开关元件，如图4所示的驱动电路42包括开关元件VT1、VT2、VT3、VT4、VT5、VT6，开关元件VT1、VT2、VT3、VT4、VT5、VT6组成三相电桥，其中VT1、VT3、VT5为上桥开关，VT2、VT4、VT6为下桥开关，开关元件可选用场效应管、IGBT晶体管等。各开关元件的栅极端分别与控制器41的驱动信号输出端电性连接，各个开关元件的漏极或源极与无刷电机17的绕组电连接。开关元件依据控制器41输出的驱动信号改变接通状态，从而改变电池包16加载在无刷电机17的绕组上的电压状态，驱动无刷电机17运转。
为了使无刷电机17转动，驱动电路42具有多个驱动状态，在一个驱动状态下电机的定子绕组会产生一个磁场，控制器41被配置为依据无刷电机17的转子转动位置输出相应的驱动信号至驱动电路42以使驱动电路42切换驱动状态，从而改变加载在无刷电机17的绕组上的电压的状态，产生交变的磁场驱动转子转动，进而实现对无刷电机17的驱动。
电动工具10还包括位置检测装置44，用于检测无刷电机17的转子171的位置。位置检测装置44可以是无传感器检测，也可以是有传感器检测。
作为一种实施方式，位置检测装置44包括位置传感器，位置传感器例如是3个霍尔传感器(未示出)，沿无刷电机17的转子171的圆周方向设置，霍尔传感器检测的转子的位置信息输入至位置检测装置44。位置检测装置44将输入的转子的位置经逻辑处理转换为可与控制器41进行通讯的转子位置信息输入至控制器41。当转子转入和转出预设范围时，霍尔传感器的信号发生改变，位置检测装置44的输出信号也随之改变。
转子转入预设范围时，位置检测装置44的输出信号定义为1，而转子转出预设范围时，位置检测装置44的输出信号定义为0。将三个霍尔传感器彼此相距物理角度120°。
参照图5，当转子171转动时，三个霍尔传感器将会产生包括六种信号组合的位置信号使得位置检测装置44输出包括六种信号组合之一的位置信号。如果按霍尔传感器放置的顺序排列则出现六个不同的信号组合100、110、010、011、001、101。这样一来位置检测装置44就可输出上述六个位置 信号之一，依据位置检测装置44输出的位置检测信号即可得知转子171所处的位置。对于具有三相绕组的无刷电机17而言，其在一个通电周期内具有六个驱动状态与上述方案产生的输出信号相对应，因此在位置检测装置44的输出信号发生变化时，无刷电机17即可执行一次换相。显然，转子171每转过60°无刷电机17换相一次，在此定义无刷电机17的一次换相至下一次换相的间隔为一个扇区。也可以说，无刷电机17具有多个换相位置，各个换相位置之间的区域为一个扇区。
为了方便说明，以下以驱动电路对应接通的接线端表示驱动电路42的驱动状态。例如，如果控制器41控制驱动电路42的开关元件使第一相绕组A连接至电源正极16a和第二相绕组B连接至电源负极16b，则该驱动状态用AB表示，如果控制器42控制驱动电路42的开关元件使第一相绕组A连接至电源负极16b和第二相绕组B连接至电源正极16a，则该驱动状态用BA表示，这样表示的驱动方式同样适用于绕组的三角型连接方案。另外，驱动状态的切换也可简称为无刷电机的换相动作。
按照上述定义，参照图4和图5，无刷电机17的转子171转动时，驱动电路42的各个开关元件、霍尔传感器的信号以及转子所处扇区位置对应如下表1所示：
Figure PCTCN2019121639-appb-000001
表1
在其他一些实施例中，位置检测装置44不包括位置传感器，而是通过反电动势信号或电机的母线电流和/或电机的端电压进行相应的计算获得间接获得转子位置，此处不予赘述，本领域技术人员可以很容易地根据本领域的专业知识获知。
控制器41电连接至驱动电路42，用以输出驱动信号控制驱动电路42工作。在一些实施例中，控制器41采用专用的控制芯片(例如，MCU，微控制单元，Microcontroller Unit)。控制芯片内部包括存储单元，用于存储制动程序和驱动程序。控制器41能够控制整个电动工具10的电路状态，实现各种电子功能，如软启动、制动、电池保护等。
电动工具10还包括运动检测装置43，运动检测装置43与电动工具10的主体部20或工作部件15关联连接，用于检测主体部20或工作部件15在至少一个方向上的运动变化，例如移动量、移动速度、旋转角速度、旋转角位移。
运动检测装置43的输出端连接至控制器41，其将检测到的结果发送给控制器41，当运动检测装置43检测到所述主体部20或工作部件15在至少一个方向上的运动变化量超过预设阈值时，控制器41控制驱动电路42的使所述无刷电机17进入制动模式。
控制器41通过运动检测装置43检测到的电动工具10的所述主体部20或所述工作部件在至少一 个方向上运动变化量，将其与预设阈值进行比较来判断电动工具10是否发生反冲，如果超过预设阈值，则判断电动工具10发生反冲，从而控制器41控制电动工具10进入制动模式，进行紧急制动，以避免发生安全事故。
作为一种实施方式，运动检测装置43具体可以包括一个陀螺仪传感器，更具体地，所述的陀螺仪传感器为MEMS9(微机电系统)多轴陀螺仪传感器，用于检测主体部20或工作部件15在至少一个方向上的旋转的角速度和角位移中的至少一个。例如，检测主体部20或工作部件15绕Z轴转动的角速度和角位移中的至少一个。MEMS陀螺仪传感器较小且可以轻易地结合到现有电路中，并输出传感器可以缩放的电压。
在一些实施方式中，陀螺仪传感器可以安装在电动工具10的主体部20，对于链锯而言，在发生反冲时，前手柄靠近旋转中心，为了测得较大的角速度或者移动量，陀螺仪传感器可以安装在远离前把手12的各种位置上，例如导板151的前端、主把手13上。陀螺仪传感器的安装位置的选择，应尽量保证能够准确检测到电动工具10的主体部20或工作部件15的旋转的角速度和角位移中的至少一个，在此并不做限制。在一些实施方式中，陀螺仪传感器测量电动工具10移动的角速度，通过角速度进行积分运算得到角位移。当陀螺仪传感器检测到的角速度和角位移中的至少一个超过预设阈值时，控制器41控制驱动电路42使无刷电机17进入制动模式。
作为一种实施方式，陀螺仪传感器用于检测主体部20或工作部件15在至少一个方向上旋转的角速度和角位移，控制器41被配置为：在角速度的值大于第一预设角速度阈值且小于第二预设角速度阈值，且角位移的值大于预设角位移阈值时，控制驱动电路42使无刷电机17进入制动模式。
可选地，在陀螺仪传感器检测到电动工具10旋转的角速度W的值大于或等于第一预设角速度阈值TW1且小于或等于第二预设角速度阈值TW2，且旋转角位移θ大于或等于预设角位移阈值Tθ时，控制器41控制驱动电路42的开关元件使无刷电机17进入制动模式。
作为另一种实施方式，陀螺仪传感器用于检测主体部20或工作部件15在至少一个方向上旋转的角速度；控制器41被配置为：在角速度的值大于预设角速度阈值时，控制驱动电路42使无刷电机17进入制动模式。当电动工具10转动的旋转角速度W很大，例如，大于第二预设角速度阈值TW2时，则不需要再判断角位移θ，就能确定发生反冲。因此，在陀螺仪传感器检测到电动工具10移动的角速度W大于第二预设角速度TW2时，控制器41控制驱动电路42的开关元件使所述无刷电机17进入制动模式。
参照图6，作为一种实施方式的电动工具10的控制方法，包括以下步骤：
步骤S60：电动工具上电；
步骤S61：获取陀螺仪传感器采集的旋转角速度W；
可选地，陀螺仪传感器检测主体部20或工作部件15绕Z轴转动的旋转角速度W。
步骤S62：对旋转角速度W进行积分运算，获取角位移θ；
控制器41对获得的旋转角速度W进行积分运算，以获得主体部20或工作部件15绕Z轴转动的角位移θ。
步骤S63：比较并判断旋转角速度W是否小于第一预设角速度阈值TW1，如果是则转至步骤S61，如果否则进入步骤S64；
控制器41将获得的角速度W首先与第一预设角速度阈值TW1进行大小比较，如果角速度W小于第一预设角速度阈值TW1则转至步骤S61，继续获取角速度，如果否则转至步骤S64。
步骤S64：比较并判断旋转角速度W是否小于第二预设角速度阈值TW2，如果是则转至步骤S65，如果否则转至步骤S66；
当判断角速度W大于或等于第一预设角速度阈值TW1，则再将角速度W与第二预设角速度阈值TW2进行大小比较，如果角速度W小于第二预设角速度阈值TW2则转至步骤S65进行角位移θ大小判断，如果角速度W大于或等于第二预设角速度阈值TW2，则转至步骤S66，直接进入制动模式。
步骤S65：比较并判断角位移θ是否小于预设角位移Tθ，如果是则转至步骤S61如果否则转至步骤S66；
步骤S66：进入制动模式。
上述实施方式，采用陀螺仪传感器的运动检测装置43检测电动工具10的主体部20或工作部件15旋转的角速度和角位移来检测电动工具10是否发生反冲，避免了传统的采用加速度计测加速度的反冲检测方法对振动敏感的缺陷，本实施方式反冲检测实现方式和后期数据处理更简单，振动干扰小，且反冲检测更准确。上述第一预设角速度阈值TW1、第二预设角速度阈值TW2、预设角位移Tθ由用户根据实际情况选择，以使得检测结果能够精确识别到冲击发生，在此并不做限制。
电动工具10包括驱动模式和制动模式。在驱动模式中，控制器41执行驱动程序，控制驱动电路42的开关元件使无刷电机17的转子171运转。在制动模式中，控制器41执行制动程序，控制驱动电路42的开关元件使无刷电机17进入制动模式。
在检测到发生反冲后，电动工具10进入紧急制动模式，以避免安全事故发生。对于具有三相电机的链锯而言，通常采用短接制动方法进行制动，制动时将电机的绕组短接，即通过控制器41控制驱动电路42的所有上桥开关元或下桥开关元件全部导通，使各相绕组的连接于中性点的一端相互连接，从而使各相绕组短接。通过这样的方式，利用绕组自身的电阻消耗能量，由于绕组的电阻较小，耗能很快，有一定的危险性，可能烧毁电机。并且随着链锯线速度越来越高，短接制动需要时间也会变长，在电动工具10出现反冲时，短接制动不能实现快速制动，不满足反冲情况下的安全要求。
本申请制动模式中，控制器41根据转子171的位置控制驱动电路42使绕组的电流方向与驱动模式中的电流方向相反。
作为一种实施方式，在无刷电机17进制动模式后，在制动模式的持续时间达到预设时长后，控制器41控制驱动电路42的开关元件使无刷电机17的绕组的短接。
作为另一种实施方式，在所述无刷电机17进入制动模式后，在无刷电机17的转子171的转速下降到预设阈值后，控制驱动电路42的开关元件使无刷电机17的绕组短接。
可选地，在链锯进入制动模式时，链锯的线速度大于等于15m/s。
在本实施例中，所述的制动模式包括第一制动过程和第二制动过程。在第一制动过程中，控制器41根据转子171的位置，控制驱动电路42的开关元件，使各相绕组在制动时的每一扇区的电流与驱动模式中的绕组的电流方向相反，以产生制动无刷电机17的反向力矩，直至满足预设条件后，控制器41控制电动工具10切换到第二制动过程。在本实施方式中，第二制动过程采用短接制动方式对无刷电机17进行制动，具体地，控制器41通过控制驱动电路42使无刷电机17的绕组短接进行制动。
所述的预设条件包括：第一制动过程的持续时间达到预设时长或无刷电机17的转子171转速下降到预设转速阈值或小于预设转速阈值。
参照图4和图7，作为一种具体实施方式，位置检测装置44包括霍尔传感器，无刷电机为Y型连接方式。在第一制动过程中，当在检测到反冲后，霍尔传感器实时检测转子171的位置，当转子转动到扇区1时，位置检测装置44输出010时，在制动模式下，此时应控制驱动电路42使BA相导通，对应地控制器41控制开关元件VT3和VT4导通，其余开关元件关断，这样A相和B相绕组的电流与驱动模式下的电流方向相反；当转子转动到扇区2时，位置检测装置44输出信号011，此时切换成CA导通，对应地控制器41控制开关元件VT4和VT5导通，其余开关元件关断，以此类推，直至转子171的转速下降到预设转速阈值后或第一制动过程的持续时间达到预设时长后切换到第二制动过程。当然，第一制动过程中，可以使所有扇区的绕组的电流与驱动模式下的电流方向相反以实现快速制动，也可以是少于所有扇区的多个扇区的绕组的电流与驱动模式下的电流方向相反，通过改变第一制动过程中与驱动模式下的电流方向相反的扇区的数量，来实现制动时间调节，数量越多，制动时间越短，数量越少，制动时间越长。
也即是说，第一制动过程中，通过控制器41控制驱动电路42的开关元件的通断状态以实现无刷电机17的制动，通过改变导通的开关，使绕组在第一制动过程中的电流与驱动模式时的电流方向相反，从而使无刷电机17反相序运转，该制动过程维持时长可以通过软件方式实现，通过输出一定的或变化的占空比，当无刷电机17的转速或转子171的转速下降到预设转速阈值或第一制动过程的持续时间达到预设时长后再切换到第二制动过程，使得制动时间可调，可以设置较短的制动时间，制动效果更优。
第一制动过程中，转子扇区位置、霍尔信号、导通开关元件以及导通绕组的关系如下表2所示，该表可以存储在存储器中，控制器41可以按照该表执行第一制动过程：
Figure PCTCN2019121639-appb-000002
Figure PCTCN2019121639-appb-000003
表2
第一制动过程的制动方式，其制动时间可调节，但无法判断电机何时停止转动。本实施方式中，在进入第一制动过程后，在无刷电机17的转速或转子171的转速下降达到预设转速阈值或第一制动过程持续时间达到预设时长后，切换成第二制动过程的短接制动，防止无刷电机的转子171朝着相反的方向继续旋转，第一制动过程制动时间可调，能够实现快速制动。
在第二制动过程中，控制器41控制上桥开关元件VT1、VT2和VT3全部导通或下桥开关元件VT4、VT6和VT2全部导通，使三相绕组短接，无刷电机17的惯性转动将产生反向的力矩，使无刷电机17迅速停止。由于第二制动过程采用短接制动方式，无刷电机17的绕组全部被短接，无刷电机17的动能消耗在绕组上，由于绕组上的电阻比较小，会产生很大的短路电流，无刷电机17的动能很快被快速释放掉，使无刷电机17瞬时产生极大的制动力矩，能够达到快速刹车的效果。
本实施方式采用在第一制动过程中，在达到预设条件后切换到第二制动过程，可使无刷电机17快速停止且制动过程更加安全可靠。
参照图8，作为一种实施方式的电动工具10的制动方法，包括如下步骤：
S80：进入制动模式；
当控制器41根据陀螺仪传感器采集到的旋转角速度W以及根据旋转角速度W积分得到的旋转角位移θ，判断电动工具10发生反冲后，进入制动模式。
S81：启动第一制动过程；
在制动模式中，控制器41首先启动第一制动过程，执行第一制动程序；
S82：获取转子实时位置；
位置检测装置44实时检测转子的位置，作为一种实施方式，通过霍尔传感器检测转子的位置，当转子转动至能被霍尔传感器的预设范围时，位置传感器处于一种信号状态，当转子转出预设范围时位置传感器切换至另一信号状态。霍尔传感器的信号输出至位置检测装置44，位置检测装置44将输入的转子的位置经逻辑处理转换为可与控制器41通讯的转子位置信息输入至控制器41，控制器41根据霍尔传感器的信号判断转子当前所处扇区位置。
S83：根据转子位置控制驱动电路使绕组在每个扇区的电流反向；
控制器41根据转子当前所处扇区位置，通过预先存储在存储器中的第一制动过程中转子扇区位置、霍尔信号、导通开关元件的关系表(表2)，控制驱动电路42的对应的开关元件导通或关断，以使绕组在每个扇区的电流与驱动模式下的电流反向，从而产生制动无刷电机17的反向力矩。
S84：判断第一制动过程的持续时间是否达到预设时长，如果是，则转至步骤S85，如果否，则转至步骤S83；
可选地，电动工具10包含定时器或计时器，定时器或计时器可以是内置于控制器41，也可以是外置于控制器41，定时器或计时器用于确定第一制动过程的持续时间。在一些具体的实施方式中，当进入制动模式时，定时器或计时器开始工作，当第一制动过程的持续时间达到预设时长后转至步骤S84，如果否，则转至步骤S83，则继续维持第一制动过程。
S85：启动第二过程；
当判断第一制动过程的持续时间达到预设时长后，控制器41启动第二制动过程。
S86：控制驱动电路的开关元件使绕组短接；
控制器41控制驱动电路42的全部下桥开关元件或全部上桥开关元件导通，使三相绕组短接，无刷电机17的动能消耗在绕组上，由于绕组上的电阻比较小，会产生很大的短路电流，无刷电机17的动能很快被快速释放掉，使无刷电机17瞬时产生极大的制动力矩，能够达到快速刹车的效果。
S87：结束制动模式。
参照图9，作为另一种实施方式的电动工具10的制动方法，包括如下步骤：
S90：启动制动模式；
当控制器41根据陀螺仪传感器采集到的旋转角速度W以及根据旋转角速度W积分得到的旋转角位移θ，判断电动工具10发生反冲后，进入制动模式。
S91：启动第一制动过程；
在制动模式中，控制器41首先启动第一制动过程，执行第一制动程序；
S92：获取转子实时位置；
位置检测装置44实时检测转子的位置，在本实施方式中，通过霍尔传感器检测转子的位置，当转子转动至能被霍尔传感器的预设范围时，位置传感器处于一种信号状态，当转子转出预设范围时位置传感器切换至另一信号状态。霍尔传感器的信号输出至位置检测装置44，位置检测装置44将输入的转子的位置经逻辑处理转换为可与控制器41通讯的转子位置信息输入至控制器41，控制器41根据霍尔传感器的信号判断转子当前所处扇区位置。
S93：根据转子位置控制驱动电路的开关元件使绕组在每个扇区的电流反向；
控制器41根据转子当前所处扇区位置，通过预先存储在存储器中的第一制动过程中转子扇区位置、霍尔信号、导通开关元件的关系表(表2)，控制驱动电路42的对应的开关元件导通或关断，以使绕组在每个扇区的电流与驱动时的电流方向相反，从而产生制动所述无刷电机17的反向力矩。
S94：判断转子转速是否下降至规定值，如果是，则转至步骤S95，如果否，则转至步骤S93；
电动工具10包含速度检测装置，用于检测转子171的转速或电机轴转速，并将检测到的结果发送到控制器41，速度检测装置可以是内置于控制器41，也可以是外置于控制器41，控制器41将速度 检测装置检测到的转速与预设的规定值进行比较来判断转子171的转速是否下降到预设转速阈值，如果是，则转至步骤S95，如果否，则转至步骤S93，继续进行制动控制。
S95：启动第二过程；
当判断判断转子171的转速下降至预设转速阈值后，控制器41切换到第二制动过程。
S96：控制驱动电路使绕组短接；
控制器41控制驱动电路42的全部下桥开关元件或上桥开关元件导通，使三相绕组短接，无刷电机17的动能消耗在绕组上，由于绕组上的电阻较小，会产生较大的短路电流，无刷电机17的动能很快被快速释放掉，使无刷电机17的瞬时产生极大的制动力矩，能够达到快速刹车的效果。
S97：结束制动模式。
经过实验，以链锯为例，当锯链的线速度为18.973m/s，采用原短接制动时的制动时间为153.4ms，而本方案的制动时间为93.4ms，与原制动方式相比，本方案的制动时间要小于短接制动方式的制动时间，满足制动时间小于0.12s的安规要求，可有效避免反冲带来的安全事故。
在本申请实施方式中，工作部件15是通过无刷电机17直接驱动的，考虑到设计需要，在其他实施方式中，也可以设置一个与无刷电机17连接的齿轮传动组件(图未示)。

Claims (21)

  1. 一种链锯，包括：
    工作部件，包括导板和锯链；
    主体部，能够安装所述工作部件；
    无刷电机，用于驱动所述工作部件工作，所述无刷电机具有驱动模式和制动模式；所述无刷电机包括转子和绕组；
    供电装置，用于为所述无刷电机提供电能；
    驱动电路，与所述供电装置和所述绕组连接，用于将所述供电装置的电能加载至所述无刷电机的绕组；
    控制器，与所述驱动电路连接，用于控制所述驱动电路；
    运动检测装置，与所述主体部或所述工作部件关联连接，用于检测所述主体部或所述工作部件在至少一个方向上的运动变化；
    所述控制器被配置为：
    在所述主体部或所述工作部件在至少一个方向上的运动变化量超过预设阈值时，控制所述驱动电路使所述无刷电机进入所述制动模式。
  2. 根据权利要求1所述的链锯，其中，
    所述控制器被配置为：
    在所述主体部或所述工作部件在至少一个方向上旋转的角速度的值大于第一预设角速度阈值且小于第二预设角速度阈值，且所述主体部或所述工作部件在至少一个方向上旋转的角位移的值大于预设角位移阈值时，控制所述驱动电路使所述无刷电机进入所述制动模式。
  3. 根据权利要求1所述的链锯，其中，
    所述控制器被配置为：
    在所述主体部或所述工作部件在至少一个方向上旋转的角速度的值大于预设角速度阈值时，控制所述驱动电路使所述无刷电机进入所述制动模式。
  4. 根据权利要求1所述的链锯，其中，
    所述运动检测装置包括：
    一个陀螺仪传感器，用于检测所述主体部或所述工作部件在至少一个方向上旋转的角速度和角位移中的至少一个。
  5. 根据权利要求1所述的链锯，其中，
    所述无刷电机具有驱动模式；
    所述控制器被配置为：
    在所述制动模式中，根据所述转子的位置控制所述驱动电路使所述绕组的电流方向与所述驱动模式中的电流方向相反。
  6. 根据权利要求5所述的链锯，其中，
    所述无刷电机具有多个换相位置，各个换相位置之间的区域为一个扇区；
    所述控制器被配置为：
    在所述制动模式中，根据所述转子所处扇区控制所述驱动电路使所述绕组在每个扇区的电流反向。
  7. 根据权利要求5所述的链锯，其中，
    所述控制器被配置为：
    在所述无刷电机进入所述制动模式后，制动模式在所述制动模式的持续时间达到预设时长后，控制所述驱动电路使所述无刷电机的所述绕组短接。
  8. 根据权利要求5所述的链锯，其中，
    所述控制器被配置为：
    在所述无刷电机进入所述制动模式后，在所述无刷电机的所述转子的转速下降至预设转速阈值后，控制所述驱动电路使所述无刷电机的所述绕组短接。
  9. 根据权利要求1所述的链锯，其中，
    所述制动模式包括第一制动过程和第二制动过程，
    所述控制器被配置为：
    在所述第一制动过程中，根据所述转子的位置控制所述驱动电路使所述无刷电机的所述绕组的电流方向与所述驱动模式中的电流方向相反；
    在所述第二制动过程中，控制所述驱动电路使所述无刷电机的所述绕组短接。
  10. 根据权利要求1所述的链锯，还包括：
    位置检测装置，用于检测所述无刷电机的所述转子的位置。
  11. 一种电动工具，包括：
    工作部件，用于实现所述电动工具的功能；
    主体部，能够安装工作部件；
    无刷电机，用于驱动所述工作部件工作，所述无刷电机具有驱动模式和制动模式；所述无刷电机包括转子和绕组；
    供电装置，用于为所述无刷电机提供电能；
    驱动电路，与所述供电装置和所述绕组连接，用于将所述供电装置的电能加载至所述无刷电机的绕组；
    控制器，与所述驱动电路连接，用于控制所述驱动电路；
    运动检测装置，与所述主体部或所述工作部件关联连接，用于检测所述主体部或所述工作部件在至少一个方向上的运动变化；
    所述控制器被配置为：
    在所述主体部或所述工作部件在至少一个方向上的运动变化量超过预设阈值时，控制所述驱动电路使所述无刷电机进入所述制动模式。
  12. 根据权利要求11所述的电动工具，其中，
    所述控制器被配置为：
    当所述主体部或所述工作部件在至少一个方向上旋转的角速度的值大于第一预设角速度阈值且小于第二预设角速度阈值，且所述主体部或所述工作部件在至少一个方向上旋转的角位移的值大于预 设角位移阈值时，控制所述驱动电路使所述无刷电机进入所述制动模式。
  13. 根据权利要求11所述的电动工具，其中，
    所述控制器被配置为：
    当所述主体部或所述工作部件在至少一个方向上旋转的角速度的值大于预设角速度阈值时，控制所述驱动电路使所述无刷电机进入制动模式。
  14. 根据权利要求11所述的电动工具，其中，
    所述运动检测装置包括：
    一个陀螺仪传感器，用于检测所述主体部或所述工作部件在至少一个方向上旋转的角速度和角位移中的至少一个。
  15. 根据权利要求11所述的电动工具，其中，
    所述控制器被配置为：
    在所述制动模式中，根据所述转子的位置控制所述驱动电路使所述无刷电机的所述绕组的电流方向与驱动过程中的电流方向相反。
  16. 根据权利要求15所述的电动工具，其中，
    所述控制器被配置为：
    在所述无刷电机进入所述制动模式后，当所述制动模式的持续时间达到预设时长后，控制所述驱动电路使所述无刷电机的所述绕组短接。
  17. 根据权利要求15所述的电动工具，其中，
    所述控制器被配置为：
    在所述无刷电机进入所述制动模式后，当所述无刷电机的所述转子的转速下降至预设转速阈值后，控制所述驱动电路使所述无刷电机的所述绕组短接。
  18. 一种电动工具的控制方法，其中，所述电动工具包括：
    工作部件，用于实现所述电动工具的功能；
    主体部，能够安装所述工作部件；
    无刷电机，用于驱动所述工作部件工作，所述无刷电机具有驱动模式和制动模式，所述无刷电机包括转子和绕组；
    运动检测装置，与所述主体部或所述工作部件关联连接，用于检测所述主体部或所述工作部件在至少一个方向上的运动变化；
    所述控制方法包括：
    获取所述主体部或所述工作部件在至少一个方向上的角速度和角位移中的至少一个；
    判断所述主体部或所述工作部件在至少一个方向上的角速度和角位移中的至少一个是否超过预设阈值；
    在判断所述主体部或所述工作部件在至少一个方向上的角速度和角位移中的至少一个超过所述预设阈值后，使所述电动工具进入所述制动模式。
  19. 根据权利要求18所述的电动工具的控制方法，其中，
    在所述制动模式中，根据所述转子的位置控制所述驱动电路使所述无刷电机的所述绕组的电流反向。
  20. 根据权利要求19所述的电动工具的控制方法，其中，
    在所述制动模式的持续时间达到预设时长后，使所述无刷电机的所述绕组的短接。
  21. 根据权利要求19所述的电动工具的控制方法，其中，
    在所述转子的转速下降至预设转速阈值后，使所述无刷电机的所述绕组短接。
PCT/CN2019/121639 2018-11-28 2019-11-28 链锯、电动工具以及电动工具的控制方法 WO2020108569A1 (zh)

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