Electric tool and control method thereof

Abstract

The invention discloses an electric tool and a control method thereof. The electric tool comprises a motor, and the motor comprises a driving shaft rotating around a first axis; the output mechanism comprises an output shaft which moves back and forth in the direction of an output axis; a controller for controlling the motor; the controller is configured to obtain a first characteristic parameter when the motor receives a shutdown operation instruction; determining a compensation parameter of the motor according to the first characteristic parameter, and controlling the motor to execute the compensation parameter; and after the motor operates in place according to the compensation parameters, controlling the motor to stop or limiting the torque output of the motor. According to the technical scheme, when the motor receives the shutdown instruction, the shutdown time or the number of turns of rotation of the motor in the shutdown process are consistent, so that the screwing depth of the rotary fastener is consistent in each shutdown process of the electric tool, and the output of the electric tool is easily controlled to enable the fastener to be flush with the workpiece.

Description

Technical Field

[0001] The present application relates to the technical field of tool equipment, and in particular to an electric tool and a method for preparing the same. Background Art

[0002] During dry construction, it is often necessary to use power tools to drive fasteners to install workpieces such as gypsum board or light panels to the wall or ceiling, and the fasteners must be flush with the workpiece.

[0003] A power tool in the related art brakes with a fixed braking force when receiving a stop command. However, when the power tool is operated under different working conditions, the speed of the motor is also different. Therefore, during the shutdown process of the power tool, the depth of the rotating fastener is not consistent, making it difficult to control the power tool output so that the fastener is flush with the workpiece.

[0004] This section provides background information related to the present application which is not necessarily prior art. Summary of the invention

[0005] One object of the present application is to solve or at least alleviate part or all of the above problems. To this end, one object of the present application is to provide an electric tool and a control method thereof in which a rotating fastener is screwed into a consistent depth during a shutdown process.

[0006] In order to achieve the above objectives, this application adopts the following technical solutions:

[0007] In one aspect, the present invention provides a power tool for drywall construction, comprising:

[0008] case;

[0009] a motor disposed at least partially within the housing, the motor including a drive shaft rotatable about a first axis;

[0010] A power supply, used to supply power to the motor;

[0011] An output mechanism, for outputting torque; the output mechanism comprises an output shaft rotating about an output axis;

[0012] A power switch, used to receive an operation instruction from a user and control the current between the motor and the power supply according to the operation instruction;

[0013] A controller for controlling the motor;

[0014] The controller is configured to: obtain a first characteristic parameter when the motor receives a shutdown operation instruction; determine a compensation parameter of the motor based on the first characteristic parameter, and control the motor to execute the compensation parameter; and control the motor to shut down or limit the torque output of the motor after the motor runs into place according to the compensation parameter.

[0015] In some embodiments, the power switch includes a first switch and a control switch; the signals of the first switch and the control switch are connected in series; the first switch is used to respond to the movement state of the output shaft, and the output shaft moves back and forth along the output axis direction; the control switch is used to respond to the user's manual operation; the controller is also configured to: when at least one of the first switch and the control switch is in an inactivated state, send a shutdown operation instruction to the motor.

[0016] In some embodiments, the controller is specifically configured to: determine the load state of the motor according to the first characteristic parameter; and determine the compensation parameters of the motor according to the load state of the motor.

[0017] In some embodiments, the first characteristic parameter includes: at least one parameter value of a motor speed-related parameter and a motor current-related parameter.

[0018] In some embodiments, the first characteristic parameter includes at least one parameter value of the output shaft's rotational speed, the output shaft's rotational angle, and the output shaft's rotational acceleration.

[0019] In some embodiments, the load state of the motor includes at least a light load state and a heavy load state; the controller is specifically configured as follows: when the parameter value satisfies a first preset parameter value, the load state of the motor is determined to be a light load state; when the parameter value does not satisfy the first preset parameter value, the load state of the motor is determined to be a heavy load state; wherein the load value of the light load state is less than the load value of the heavy load state.

[0020] In some embodiments, the compensation parameters include at least one of: the number of compensated rotations, the compensation rotation time, and the compensation rotation angle.

[0021] In some embodiments, the electric tool further includes: a detection component for detecting the first characteristic parameter.

[0022] In some embodiments, the compensation parameter is determined by the difference between the preset operating parameter and the real-time operating parameter; wherein the preset operating parameter is determined by querying a first calibration table based on the first characteristic parameter; the real-time operating parameter is determined by fitting based on the first characteristic parameter; or, the real-time operating parameter is determined by querying a second calibration table based on the first characteristic parameter.

[0023] In a second aspect, the present invention further provides a method for controlling an electric tool, comprising:

[0024] When the motor receives a shutdown operation instruction, a first characteristic parameter is obtained;

[0025] Determining a compensation parameter of the motor according to the first characteristic parameter;

[0026] Control the motor to execute compensation parameters;

[0027] When the motor runs into place according to the compensation parameters, the motor is controlled to stop or the torque output of the motor is limited.

[0028] In some embodiments, determining the compensation parameter of the motor according to the first characteristic parameter includes: determining the load state of the motor according to the first characteristic parameter; and determining the compensation parameter of the motor according to the load state of the motor.

[0029] The benefits of the present application lie in that: when the motor receives a shutdown operation instruction, a first characteristic parameter is obtained, thereby determining the compensation parameter of the motor based on the first characteristic parameter, and controlling the motor to execute the compensation parameter; when the motor operates in place according to the compensation parameter, the motor is controlled to shut down or the torque output of the motor is limited, so that after the motor receives the shutdown operation instruction, the shutdown time or the number of motor rotations during the shutdown process is consistent, so that the depth of the rotating fastener is consistent during each shutdown process of the power tool, thereby ensuring that the power tool is not affected by external factors (such as power changes, load changes) during operation, and ensuring consistency throughout the entire operation process. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 A schematic diagram of the structure of an electric tool provided by an embodiment of the present invention;

[0031] Figure 2 A cross-sectional view of an electric tool provided by an embodiment of the present invention;

[0032] Figure 3 A partial cross-sectional view of an electric tool provided by an embodiment of the present invention;

[0033] Figure 4 for Figure 2 A magnified image of area A;

[0034] Figure 5 A control circuit diagram of an electric tool provided by an embodiment of the present invention;

[0035] Figure 6 A flow chart of a control method for an electric tool provided by an embodiment of the present invention;

[0036] Figure 7 A flowchart of another method for controlling an electric tool provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0037] Before any embodiments of the application are explained in detail, it is to be understood that the application is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the above drawings.

[0038] In this application, the terms "comprises", "includes", "has" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device that includes a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of more restrictions, an element defined by the sentence "comprises a ..." does not exclude the presence of other identical elements in the process, method, article or device that includes the element.

[0039] In this application, the term "and / or" is a description of the association relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this application generally indicates that the related objects before and after are in an "and / or" relationship.

[0040] In the present application, the terms "connect", "combine", "couple", and "install" may refer to direct connection, combination, coupling, or installation, or indirect connection, combination, coupling, or installation. For example, direct connection refers to two parts or components being connected together without the need for an intermediate piece, and indirect connection refers to two parts or components being connected to at least one intermediate piece respectively, and the two parts or components being connected via the intermediate piece. In addition, "connect" and "couple" are not limited to physical or mechanical connections or couplings, and may include electrical connections or couplings.

[0041] In the present application, it will be understood by those of ordinary skill in the art that relative terms (e.g., "about," "approximately," "substantially," etc.) used in conjunction with quantities or conditions include the values ​​and have the meaning indicated by the context. For example, the relative terms include at least the degree of error associated with the measurement of a specific value, the tolerances caused by manufacturing, assembly, and use associated with a specific value, and the like. Such terms should also be considered to disclose a range defined by the absolute values ​​of the two endpoints. Relative terms may refer to plus or minus a certain percentage (e.g., 1%, 5%, 10% or more) of the indicated value. Numerical values ​​that do not use relative terms should also be disclosed as specific values ​​with tolerances. In addition, "substantially" may refer to plus or minus a certain degree (e.g., 1 degree, 5 degrees, 10 degrees or more) on the basis of the indicated angle when expressing a relative angular position relationship (e.g., substantially parallel, substantially perpendicular).

[0042] In this application, it will be understood by those skilled in the art that the function performed by a component can be performed by one component, multiple components, one part, or multiple parts. Similarly, the function performed by a part can also be performed by one part, one component, or a combination of multiple parts.

[0043] In the present application, the terms "upper", "lower", "left", "right", "front", "back" and other directional words are described based on the orientation and positional relationship shown in the accompanying drawings, and should not be understood as limiting the embodiments of the present application. In addition, in the context, it is also necessary to understand that when it is mentioned that an element is connected to another element "upper" or "lower", it can not only be directly connected to another element "upper" or "lower", but also indirectly connected to another element "upper" or "lower" through an intermediate element. It should also be understood that directional words such as upper side, lower side, left side, right side, front side, back side, etc. not only represent the positive orientation, but can also be understood as the lateral orientation. For example, the bottom can include directly below, lower left, lower right, lower front, and lower back, etc.

[0044] In this application, the terms "controller", "processor", "central processing unit", "CPU", and "MCU" are interchangeable. When a unit "controller", "processor", "central processing unit", "CPU", or "MCU" is used to perform a specific function, unless otherwise specified, these functions can be performed by a single unit or multiple units.

[0045] In the present application, the terms “device”, “module” or “unit” may be implemented in the form of hardware or software to achieve specific functions.

[0046] In this application, the terms "calculate", "judge", "control", "determine", "identify", etc. refer to the operations and processes of a computer system or similar electronic computing device (e.g., controller, processor, etc.).

[0047] In order to clearly illustrate the technical solution of the present application, an upper side, a lower side, a left side, a right side, a front side and a rear side are defined in the drawings of the specification.

[0048] like Figure 1 and Figure 2 The electric tool of one embodiment of the present application is shown. The electric tool is an electric screwdriver 100. The electric screwdriver 100 is a dry construction electric tool used to drive fasteners such as screws into gypsum drywall.

[0049] like Figures 1 to 4 As shown, the electric screwdriver 100 includes a power supply 30. In this embodiment, the power supply 30 is a DC power supply. The DC power supply is used to provide electrical energy to the electric screwdriver 100. The DC power supply is a battery pack, and the battery pack cooperates with the corresponding power supply circuit to power the electric screwdriver 100. Those skilled in the art should understand that the power supply 30 is not limited to the scenario of using a DC power supply, and can also be powered by AC power, AC power, and corresponding rectification, filtering and voltage regulation circuits to realize power supply to the corresponding components in the machine.

[0050] The electric screwdriver 100 includes a housing 11, a motor 12, a transmission mechanism 13, and an output mechanism 14. The motor 12 includes a drive shaft 121 that rotates about the first axis 101. In this embodiment, the motor 12 is specifically configured as an electric motor, and the motor 12 will be used to replace the motor, and the motor shaft 121 will be used to replace the drive shaft, but this cannot be used as a limitation to the present application.

[0051] The output mechanism 14 is used to drive a working accessory (not shown in the figure) to rotate and output torque. The output mechanism 14 includes an output shaft 141. A clamping assembly 142 is provided at the front end of the output shaft 141, which can clamp corresponding working accessories (not shown in the figure) when implementing different functions, such as screwdriver bits, drill bits, sleeves, etc., so as to drive fasteners such as screws into cement and wood. In this embodiment, the working accessory can be a screwdriver bit.

[0052] The output shaft 141 can rotate with the output axis as the axis, so as to move forward and backward along the direction of the output axis to output power. In this embodiment, the output axis is the second axis 102. In this embodiment, the first axis 101 and the second axis 102 are parallel to each other but do not overlap. In this embodiment, the output shaft 141 is roughly arranged on the upper side of the motor shaft 121. In other alternative embodiments, the second axis 102 is arranged at a certain angle with the first axis 101. In other alternative embodiments, the first axis 101 and the second axis 102 overlap.

[0053] The output shaft 141 can be moved along the front-to-rear direction of the second axis 102 under the force, and can return to the original position when the external force is removed.

[0054] The housing 11 includes a main body shell 111 and a grip portion 113. The main body shell 111 is configured as a long hollow body, and the motor 12 and part of the output mechanism 14 are accommodated in the main body shell 111. The main body shell 111 is also formed or connected with a grip portion 113 for user operation. The grip portion 113 and the main body shell 111 form a T-shaped or L-shaped structure, which is convenient for the user to hold and operate. One end of the grip portion 113 is connected to a power supply 30.

[0055] The transmission mechanism 13 is used to transmit the power output by the motor shaft 121 to the output shaft 141. The transmission mechanism 13 includes a first transmission member 131 and a second transmission member 132. The first transmission member 131 is fixedly connected to the motor shaft or integrally formed, and the second transmission member 132 rotates synchronously with the output shaft 141. The first transmission member 131 and the second transmission member 132 are always in meshing connection. The second transmission member 132 always maintains at least partial contact during the process in which the output shaft 141 is forced to move along the second axis 102. A slide groove (not shown in the figure) is formed on the second transmission member 132 for reciprocating motion of the output shaft 141, and a sliding portion (not shown in the figure) is fixedly connected or integrally formed on the output shaft 141. The sliding portion and the slide groove are always matched to ensure that the second transmission member 132 and the output shaft 141 rotate synchronously.

[0056] The electric screwdriver 100 also includes an elastic member 15. When the input end 411 of the output shaft is forced to move along the second axis 102, so that the output end 412 of the output shaft moves backward along the second axis 102, the elastic member 15 is used to apply a force to the output shaft 141 to restore it to its original position, and the elastic member 15 is sleeved on the output shaft 141. One end of the elastic member 15 abuts on the protrusion formed on the output shaft 141, and the other end abuts on the second transmission member 132. The output shaft 141 is forced to move backward, so that the elastic member 15 is elastically deformed and generates a deformation force. When the external force is removed, the output shaft 141 returns to its original position due to the deformation force. In fact, we can easily find that the original position of the output shaft 141 is often not fixed due to installation or operation reasons. We don’t care here. As long as the position of the output shaft 141 is not affected by any external force, it can be understood as the original position.

[0057] Figure 5 A control circuit diagram of an electric tool provided by an embodiment of the present invention. Figure 5 As shown, the motor 12 includes a stator winding and a rotor. In some embodiments, the motor 12 is a three-phase brushless motor, including a rotor with permanent magnets and three-phase stator windings U, V, and W that are electronically commutated. In some embodiments, the three-phase stator windings U, V, and W are connected in a star connection, and in other embodiments, the three-phase stator windings U, V, and W are connected in an angle connection. However, it must be understood that other types of brushless motors are also within the scope of the present disclosure. The brushless motor may include less than or more than three phases.

[0058] The electric screwdriver 100 includes a control component. The control component includes a switch circuit 171 and a controller 17. The switch circuit 171 is electrically connected to the stator windings U, V, and W of the motor 12, and is used to transfer the current from the power supply 30 to the stator windings U, V, and W to drive the motor 12 to rotate. In one embodiment, the switch circuit 171 includes a plurality of switch elements Q1, Q2, Q3, Q4, Q5, and Q6. The gate terminal of each switch element is electrically connected to the controller 17 for receiving a control signal from the controller 17. The drain or source of each switch element is connected to the stator windings U, V, and W of the motor 12. The switch elements Q1-Q6 receive control signals from the controller 17 to change their respective conduction states, thereby changing the current loaded by the power supply 30 on the stator windings U, V, and W of the motor 12. In one embodiment, the switch circuit 171 can be a three-phase bridge driver circuit including six controllable semiconductor power devices (such as FET, BJT, IGBT, etc.). It can be understood that the above-mentioned switching element can also be any other type of solid-state switch, such as an insulated gate bipolar transistor (IGBT), a bipolar junction transistor (BJT), etc.

[0059] In this embodiment, the controller 17 is used to control the motor 12. The controller 17 is arranged on a control circuit board, and the control circuit board includes: a PCB circuit board (Printed Circuit Board) and an FPC circuit board (Flexible Printed Circuitboard). The controller 17 uses a dedicated control chip, for example, a single chip microcomputer, a microcontroller unit MCU (Microcontroller Unit). The controller 17 specifically controls the on or off state of the switch element in the switch circuit 171 through the control chip. In some embodiments, the controller 17 controls the ratio between the on time and the off time of the drive switch based on a pulse width modulation (PWM) signal. It should be noted that the control chip can be integrated into the controller 17, or can also be set independently of the controller 17. As for the structural relationship between the drive chip and the controller 17, this embodiment does not limit it.

[0060] The electric screwdriver 100 further includes a power switch 16, which is used for a user to operate to control the power-on state of the motor 12. The power switch 16 includes a control switch 161 and a first switch 162, wherein the control switch 161 is arranged near the grip 113, and is used to send start and stop signals to the motor when manually operated by the user. The first switch 162 is arranged in the housing 111, and the signal of the first switch 162 responds to the motion state of the output shaft 141. In this embodiment, the control switch 161 and the signal of the first switch 162 are arranged in series.

[0061] The control switch 161 includes an operating member 1611 and a switch element 1612 connected to the operating member 1611. The operating member 1611 is used to receive an operation instruction from a user. Generally speaking, when the operating member 1611 is activated, the switch element 1612 is turned on, and when the operating member 1611 is not activated, the switch element 1612 is turned off. In this embodiment, the user inputs an operation instruction by pressing and releasing the operating member 1611. In some alternative embodiments, the user inputs an operation instruction to the operating member 1611 by operating actions such as rotating, toggling, or touching.

[0062] The first switch 162 includes a detection element 1621 and an activation element 1622. The detection element 1621 is coupled to the motor 12, and the activation element 1622 is used to activate the detection element 1621. In this embodiment, the activation element 1622 activates the detection element 1621 in response to the movement of the output shaft 141. The process of the movement of the detection element 1621 includes an activation state in which the activation element 1622 is activated and generates an activation signal and a sleep state in which the activation element is not activated. In this embodiment, when the detection element 1621 is in an activated state and the control switch 161 is in a conducting state, the motor 12 is started. That is, when the detection element 1621 is in a sleep state or the control switch 161 is in a closed state, the motor 12 cannot be started. It should be noted that the output shaft 141 driving the detection element 1621 to move can be understood as the output shaft 141 directly driving the detection element 1621 to translate, rotate, slide, etc., or the output shaft 141 can indirectly drive the detection element 1621 to translate, rotate, slide, etc. In this embodiment, the output shaft 141 drives the detection element 1621 to rotate around the first rotation axis 103 , and can be activated by the activation element 1622 during the rotation process, so that the detection element 1621 is in an activated state.

[0063] In this embodiment, the output shaft 141 drives the detection element 1621 to rotate. For example, when the input end 411 is forced to move along the second axis 102 so that the output end 412 moves backward along the second axis 102, the output end 412 can drive the detection element 1621 to rotate around the first rotation axis 103.

[0064] In this embodiment, the first switch 162 further includes: a rotating member 1623, a biasing member 1624 and a connecting member 1625. The rotating member 1623 is rotatably connected to the transmission housing 21 through the connecting member 1624. The rotating member 1623 is used to install the detection element 1621. It can also be understood that the output shaft 141 drives the rotating member 1623 to rotate around the first rotation axis 103, thereby driving the detection element 1621 to rotate. The biasing member 1624 is installed on the rotating member 1623. For example, when installed, the biasing member 1624 has a biasing force, which can keep the rotating member 1623 in the initial position when there is no external force. In this embodiment, the rotating member 1623 includes a connecting portion 1626 and a mounting portion 1627, wherein the mounting portion 1627 is formed with a receiving groove, and the detection element 1621 is installed in the receiving groove and rotates synchronously with the rotating member 1623. The connecting portion 1626 is fixedly connected or integrally formed with the mounting portion 1627, for example, the connecting portion 1626 is integrally formed with the mounting portion 1627. The biasing member 1624 can provide a biasing force that keeps the detection element 1621 in the initial position without external force driving, that is, when there is no external force driving the output shaft 141, the biasing member 1624 keeps the detection element 1621 in the initial position. Under the premise that the control switch 161 is in a state of being always on, when the input end 411 is forced to move along the first axis 101 in a direction close to the motor shaft 121, the output end 412 can drive the detection element 1621 to switch from a sleep state to an active state, wherein when the detection element 1621 is in the sleep state, the output end 412 is at least partially in contact with the connecting portion 1626. That is to say, when the detection element 1621 is in the active state, the detection element 1621 is at least partially in contact with the activation element 1622. The output shaft 141 has a driving member 1411. The driving member 1411 can drive the connecting portion 1626 to rotate the detecting element 1621. The driving member 1411 can be a rolling ball. The above arrangement can avoid damage to the connecting portion 1626 when the motor 12 drives the output shaft 141 to run at a high speed, thereby extending the service life. In this embodiment, the detecting element 1621 adopts a Hall sensor, and the activating element 1622 adopts a permanent magnet. It should be noted that the output end 412 described above can also be formed by the driving member 1411.

[0065] In the present embodiment, the electric screwdriver 100 further includes a switching switch 18, which is used for the user to operate to switch the working mode of the electric screwdriver. The working mode of the electric screwdriver includes at least a pulse working mode. In the present embodiment, the electric screwdriver also includes a continuous working mode. In the pulse working mode, the motor drives the output shaft to rotate and output intermittently. For example, when the power switch controls the motor to be powered on, the motor runs at a certain on-off ratio. When the motor rotates, the output shaft is driven to output power. It should be explained that the on-off ratio is the ratio of the motor downtime or the motor running time to the total running time in the pulse working mode, so as to ensure that the motor drives the output shaft to rotate and output intermittently in a certain pattern. In the continuous working mode, the motor drives the output shaft to rotate and output continuously. For example, when the power switch controls the motor to be powered on, the motor runs continuously to drive the output shaft to continuously output power.

[0066] The switch 18 is disposed above the housing for manual operation by the user. In the present embodiment, the switch 18 is located above the output axis. In the present embodiment, the user inputs the operation instruction of switching the working mode by pressing the switch 18. In some alternative embodiments, the user inputs the operation instruction of switching the working mode by operating actions such as rotation, toggling or touching.

[0067] In this embodiment, the controller is configured to: obtain a first characteristic parameter when the motor receives a shutdown operation instruction; determine the compensation parameter of the motor based on the first characteristic parameter, and control the motor to execute the compensation parameter; when the motor operates in place according to the compensation parameter, control the motor to shut down or limit the torque output of the motor.

[0068] The first characteristic parameter may be a parameter related to the motor 12 or a parameter related to the output shaft 141. The compensation parameter of the motor 12 may be a parameter for the motor 12 to continue to run from the time when the motor 12 receives the shutdown operation instruction to the time when the motor 12 stops. Optionally, the compensation parameter includes at least one of the number of compensated rotations, the compensation rotation time, and the compensation rotation angle. Limiting the torque output of the motor 12 may be controlling the torque output of the motor 12 so that the output shaft 141 cannot drive the fastener to rotate under the current working condition.

[0069] In an optional embodiment, the controller is further configured to send a shutdown operation instruction to the motor when at least one of the first switch 162 and the control switch 161 is in an inactive state.

[0070] Specifically, when the user operates the control switch 161 to disconnect the control switch 161, or when the first switch 162 responds to the movement state of the output shaft 141 to disconnect the first switch 162, the controller sends a shutdown operation instruction to the motor 12. When the motor 12 receives the shutdown operation instruction, the controller obtains the first characteristic parameter, thereby determining the compensation parameter of the motor 12 according to the first characteristic parameter, and controls the motor 12 to execute the compensation parameter. When the motor 12 runs into place according to the compensation parameter, the controller controls the motor 12 to stop, or limits the torque output of the motor 12, so that the output shaft 141 cannot drive the fastener to rotate under the current working condition. That is to say, when the motor 12 runs into place according to the compensation parameter, the motor enters the braking operation process, and the power tool will stop driving the fastener.

[0071] In this embodiment, when the motor 12 receives the shutdown operation instruction, the first characteristic parameter is obtained, so that the compensation parameter of the motor 12 is determined according to the first characteristic parameter, and the motor 12 is controlled to execute the compensation parameter; when the motor 12 is in place according to the compensation parameter, the motor 12 is controlled to shut down or the torque output of the motor 12 is limited, so that after the motor 12 receives the shutdown operation instruction, the number of rotations of the motor 12 during the shutdown process is consistent, so that the depth of the rotating fastener is consistent during each shutdown process of the power tool, so that it is easy to control the power tool output to control the consistency of the fastener screwing. Since the electric screwdriver used in drywall construction is attached with a depth regulator, the consistency of the screwing of the fastener is guaranteed, and the flushness of the fastener and the workpiece can be guaranteed. Avoid the influence of external factors (such as power changes, load changes, etc.) on the motor braking operation, so that the screwing depth of the fastener is different.

[0072] Optionally, the controller is specifically configured to: determine the load state of the motor according to the first characteristic parameter; and determine the compensation parameter of the motor according to the load state of the motor.

[0073] The load state of the motor 12 includes at least a light load state and a heavy load state. It is understandable that when the application scenario of the power tool is different, the load range of the motor 12 is also different. Therefore, the light load state and the heavy load state are the relative light load and the relative heavy load of the power tool in the current application scenario.

[0074] In this embodiment, the first characteristic parameter includes at least one parameter value of a current-related parameter of the motor 12, a speed-related parameter of the motor 12, and a rotation parameter of the output shaft 141. In this embodiment, the power tool further includes a detection component for detecting the first characteristic parameter.

[0075] It should be explained that the current-related parameters of the motor 12 include the current of the motor 12 and the parameters obtained by calculating the current of the motor 12. The detection component includes a first detection component. The current of the motor 12 is obtained by the first detection component. The first detection component includes a current sensing resistor, a Hall current sensor or a MOSFET (metal oxide semiconductor field effect transistor) on-resistance, etc.

[0076] It should be explained that the speed-related parameters of the motor 12 include the speed of the motor 12 and the parameters obtained by calculating the speed of the motor 12, such as the torque of the motor 12. When the output shaft 141 is loaded with a large load, the speed of the output shaft 141 decreases, and the speed of the motor 12 also decreases. When the output shaft 141 is loaded with a small load, the speed of the output shaft 141 increases, and the speed of the motor 12 also increases. The speed of the motor 12 is detected by a magnetic ring, a magnetic steel or a photoelectric encoder, through an inductor, a Hall sensor or a photoelectric sensor.

[0077] The rotation parameter of the output shaft 141 includes at least one parameter value of the rotation speed of the output shaft 141, the rotation angle of the output shaft 141, and the rotation acceleration of the output shaft 141. The detection component includes a second detection component. The second detection component is used to detect the rotation parameter of the output shaft 141. The second detection component includes a position sensor, which can be a photodiode sensor, a magnetic sensor or a potentiometer. The second detection component can also be a rotation sensor, specifically a gyroscope sensor. The gyroscope sensor can be a single-axis, two-axis or three-axis micro-electromechanical system (MEMS) sensor or a rotation sensor.

[0078] Optionally, the controller is specifically configured as follows: when the parameter value satisfies a first preset parameter value, the load state of the motor is determined to be a light load state; when the parameter value does not satisfy the first preset parameter value, the load state of the motor is determined to be a heavy load state; wherein the load value of the light load state is smaller than the load value of the heavy load state.

[0079] In an exemplary embodiment, when the parameter value is the rotational speed of the output shaft 141, if the rotational speed of the output shaft 141 is greater than the first preset parameter, the load state of the motor 12 is determined to be a light load state; if the rotational speed of the output shaft 141 is less than or equal to the first preset parameter, the load state of the motor 12 is determined to be a heavy load state, so that when the load state of the motor 12 is a light load state, the compensation parameter of the motor 12 is determined to be the first compensation parameter; when the load state of the motor 12 is a heavy load state, the compensation parameter of the motor 12 is determined to be the second compensation parameter.

[0080] In another exemplary embodiment, when the parameter value is the current of the motor 12, if the current of the motor 12 is less than the first preset parameter, the load state of the motor 12 is determined to be a light load state; if the current of the motor 12 is greater than or equal to the first preset parameter, the load state of the motor 12 is determined to be a heavy load state, so that when the load state of the motor 12 is a light load state, the compensation parameter of the motor 12 is determined to be a first compensation parameter; when the load state of the motor 12 is a heavy load state, the compensation parameter of the motor 12 is determined to be a second compensation parameter.

[0081] In this embodiment, the compensation parameter is determined by the difference between the preset operating parameter and the real-time operating parameter. The preset operating parameter is determined by querying the first calibration table according to the first characteristic parameter. The first calibration table is a calibration table pre-calibrated and stored in the controller. The real-time operating parameter is determined by fitting or querying the second calibration table according to the first characteristic parameter.

[0082] In an optional embodiment, when the compensating operating parameters of the motor 12 include the number of compensated rotations, when the load state of the output shaft 141 is a light load state, the first compensating parameter = the first preset operating parameter - the first real-time operating parameter. Among them, the "first preset operating parameter" is the number of brake laps at the highest speed under the light load state. It can be understood that within the load range of the light load condition, when the motor load is the smallest, the battery pack power is the highest, and the motor speed is the fastest, the number of laps the motor rotates from the time the motor receives the shutdown signal to the time the shutdown is completed. The "first real-time operating parameter" is the number of brake laps of the motor at the current speed = (K1*motor speed before braking), where K1 is the fitting coefficient of the speed and the number of brake laps. In some embodiments, the number of brake laps of the motor at the current speed = (K1*motor speed before braking - B1), where B1 is a correction constant. K1 and B1 are both obtained by using laboratory test data. For example, the same fasteners are controlled to conduct tightening experiments on the same workpiece, the motor speeds are changed, the number of motor brake circles is detected, and the discrete points are fitted according to the obtained values ​​to obtain the values ​​of K1 and B1.

[0083] In the same way, when the load state of the output shaft 141 is a heavy load state, the second compensation parameter = the second preset operating parameter - the second real-time operating parameter. The "second preset operating parameter" is the number of brake laps at the highest speed under heavy load conditions. It can be understood that within the load range of the heavy load condition, when the motor load is the smallest, the battery pack power is the highest, and the motor speed is the fastest, the number of laps the motor rotates from the time the motor receives the shutdown signal to the time the shutdown is completed. The "second real-time operating parameter" is the number of brake laps of the motor at the current speed = (K2*motor speed before braking), where K2 is the fitting coefficient of the speed and the number of brake laps. In some embodiments, the number of brake laps of the motor at the current speed = (K2*motor speed before braking - B2), where B2 is a correction constant.

[0084] Based on the same inventive concept, this embodiment also provides a control method for an electric tool. Figure 6 A flowchart of a control method of an electric tool provided by an embodiment of the present invention, referring to Figure 6 As shown, the control method of the electric tool includes:

[0085] S110. When the motor receives a shutdown operation instruction, a first characteristic parameter is obtained.

[0086] S120. Determine compensation parameters of the motor according to the first characteristic parameter.

[0087] S130, controlling the motor to execute compensation parameters.

[0088] S140, determining whether the motor is running in place according to the compensation parameters; if so, executing S150.

[0089] S150: Control the motor to stop or limit the torque output of the motor.

[0090] Specifically, when the user operates the control switch 161 to disconnect the control switch 161, or when the first switch 162 responds to the movement state of the output shaft 141 to disconnect the first switch 162, the controller sends a shutdown operation instruction to the motor 12. When the motor 12 receives the shutdown operation instruction, the controller obtains the first characteristic parameter, thereby determining the compensation parameter of the motor 12 according to the first characteristic parameter, and controls the motor 12 to execute the compensation parameter. When the motor 12 runs into place according to the compensation parameter, the controller controls the motor 12 to stop, or limits the torque output of the motor 12, so that the output shaft 141 cannot drive the fastener to rotate under the current working condition. That is to say, when the motor 12 runs into place according to the compensation parameter, the motor enters the braking operation process, and the power tool will stop driving the fastener.

[0091] Optional, Figure 7 This is a flow chart of another control method of an electric tool provided by an embodiment of the present invention. Based on the above embodiment, this embodiment further adds a step of determining the compensation parameter of the motor according to the first characteristic parameter, referring to Figure 7 As shown, the control method specifically includes:

[0092] S210: When the motor receives a shutdown operation instruction, a first characteristic parameter is obtained.

[0093] S220: Determine the load state of the motor according to the first characteristic parameter.

[0094] Optionally, the first characteristic parameter includes: at least one parameter value of the motor speed, the motor current, the motor commutation parameter and the motor freewheeling time; determining the load state of the motor according to the first characteristic parameter includes: when the parameter value satisfies the first preset parameter value, determining that the load state of the motor is a light load state; when the parameter value does not satisfy the first preset parameter value, determining that the load state of the motor is a heavy load state.

[0095] S230: Determine compensation parameters of the motor according to the load state of the motor.

[0096] The load state of the motor includes at least a light load state and a heavy load state.

[0097] S240, controlling the motor to execute compensation parameters.

[0098] S250, determining whether the motor is running in place according to the compensation parameters; if so, executing S260.

[0099] S260: Control the motor to stop or limit the torque output of the motor.

[0100] In this embodiment, when the motor receives the shutdown operation instruction, the first characteristic parameter is obtained, so that the compensation parameter of the motor is determined according to the first characteristic parameter, and the motor is controlled to execute the compensation parameter; when the motor runs in place according to the compensation parameter, the motor is controlled to stop or the torque output of the motor is limited, so that after the motor receives the shutdown operation instruction, the shutdown time or the number of motor rotations during the shutdown process is consistent, so that the depth of the rotating fastener is consistent during each shutdown process of the electric tool, so that it is easy to control the output of the electric tool to make the fastener flush with the workpiece. In addition, by determining the load state of the motor according to the first characteristic parameter, when the parameter value meets the first preset parameter value, the load state of the motor is determined to be a light load state; when the parameter value does not meet the first preset parameter value, the load state of the motor is determined to be a heavy load state, so that when the load state of the motor is a light load state, the compensation parameter of the motor is determined to be a first compensation parameter, and when the load state of the motor is a heavy load state, the compensation parameter of the motor is determined to be a second compensation parameter, without having to determine a compensation parameter of the motor for each load value, so that the electric tool can save resources while meeting the working condition requirements.

[0101] The above shows and describes the basic principles, main features and advantages of the present application. Those skilled in the art should understand that the above embodiments do not limit the present application in any form, and any technical solution obtained by equivalent replacement or equivalent transformation falls within the protection scope of the present application.

Claims

1. An electric tool for dry wall construction, characterized in that: include: case; a motor disposed at least partially within the housing, the motor including a drive shaft rotatable about a first axis; A power supply, used to supply power to the motor; An output mechanism, for outputting torque; the output mechanism comprises an output shaft rotating about an output axis; A power switch, used to receive an operation instruction from a user and control the current between the motor and the power supply according to the operation instruction; A controller, used for controlling the motor; The controller is configured to: obtain a first characteristic parameter when the motor receives a shutdown operation instruction; determine a compensation parameter of the motor based on the first characteristic parameter, and control the motor to execute the compensation parameter; and control the motor to shut down or limit the torque output of the motor after the motor runs into position according to the compensation parameter.

2. The electric tool according to claim 1, characterized in that: The power switch includes a first switch and a control switch; The signals of the first switch and the control switch are connected in series; the first switch is used to respond to the motion state of the output shaft, and the output shaft moves forward and backward along the output axis direction; the control switch is used to respond to the manual operation of the user; The controller is further configured to send a shutdown operation instruction to the motor when at least one of the first switch and the control switch is in an inactive state.

3. The electric tool according to claim 1, characterized in that: The controller is specifically configured to: determine the load state of the motor according to the first characteristic parameter; and determine the compensation parameter of the motor according to the load state of the motor.

4. The electric tool according to claim 3, characterized in that: The first characteristic parameter includes: at least one parameter value of a speed-related parameter of the motor and a current-related parameter of the motor.

5. The electric tool according to claim 3, characterized in that: The first characteristic parameter includes at least one parameter value of a rotation speed of the output shaft, a rotation angle of the output shaft, and a rotation acceleration of the output shaft.

6. The electric tool according to claim 4 or 5, characterized in that: The load state of the motor includes at least a light load state and a heavy load state; The controller is specifically configured as follows: when the parameter value satisfies a first preset parameter value, the load state of the motor is determined to be a light load state; when the parameter value does not satisfy the first preset parameter value, the load state of the motor is determined to be a heavy load state; wherein the load value of the light load state is smaller than the load value of the heavy load state.

7. The electric tool according to claim 1, characterized in that: The compensation parameters include: at least one of the compensation rotation number, the compensation rotation time, and the compensation rotation angle.

8. The electric tool according to claim 1, characterized in that: Also includes: A detection component is used to detect the first characteristic parameter.

9. The electric tool according to claim 1, characterized in that: The compensation parameter is determined by the difference between the preset operating parameter and the real-time operating parameter; wherein, the preset operating parameter is determined by querying a first calibration table according to the first characteristic parameter; the real-time operating parameter is determined by fitting according to the first characteristic parameter; or, the real-time operating parameter is determined by querying a second calibration table according to the first characteristic parameter.

10. A method for controlling an electric tool, characterized in that: include: When the motor receives a shutdown operation instruction, a first characteristic parameter is obtained; determining a compensation parameter of the motor according to the first characteristic parameter; controlling the motor to execute the compensation parameter; When the motor is in place according to the compensation parameter, the motor is controlled to stop or the torque output of the motor is limited.

11. The control method of the electric tool according to claim 10, characterized in that: Determining a compensation parameter of the motor according to the first characteristic parameter includes: determining a load state of the motor according to the first characteristic parameter; A compensation parameter of the motor is determined according to a load state of the motor.

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