Impact tool

Abstract

The invention discloses an impact tool. The impact tool includes: a motor including a drive shaft rotating about a first axis, through which torque is output; the battery pack at least supplies power to the motor; the output shaft is used for outputting torque outwards; the impact mechanism is used for applying impact force to the output shaft; the controller is used for controlling the motor; wherein the controller is configured to determine a required torque value of the motor after the impact mechanism applies impact force to the output shaft, match a preset voltage value of the motor according to the required torque value, and adjust operation parameters of the motor according to the relation between the current voltage value of the battery pack and the preset voltage value of the motor, the difference value parameter between the motor output torque of the motor and the required torque value under different current voltage values of the battery pack is smaller than a preset difference value parameter. The invention provides an impact tool capable of maintaining output torque when power of a direct-current power source is consumed.

Description

Technical Field

[0001] The present application relates to an electric tool, in particular to an impact tool. Background Art

[0002] Impact tools refer to tools that can output rotational motion at a certain impact frequency. Common impact tools include impact wrenches, impact screwdrivers, impact drills, etc. Impact wrenches are usually used to tighten bolts and nuts, impact screwdrivers are usually used to loosen or tighten screws, and impact drills are usually used to punch holes.

[0003] In order to output a rotational motion with a certain impact frequency, the impact tool usually includes an output component for outputting a rotational force and an impact mechanism for periodically impacting the output component, and the impact tool needs to use a power source as an energy source. In related technical products, for impact tools that use a DC power source as an energy source, as the DC power source is consumed, the output torque of the impact tool will also be affected, which will affect the user experience.

[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 impact tool that can maintain output torque when the power of the DC power supply is consumed.

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

[0007] An impact tool comprising:

[0008] an electric motor including a drive shaft rotating about a first axis and outputting torque via the drive shaft;

[0009] A battery pack, for supplying power to at least the motor;

[0010] Output shaft, used for outputting torque externally;

[0011] An impact mechanism, used for applying an impact force to the output shaft;

[0012] A controller, used for controlling the motor;

[0013] Wherein, the controller is configured as:

[0014] After the impact mechanism applies an impact force to the output shaft, the required torque value of the motor is determined, the preset voltage value of the motor is matched according to the required torque value, and the motor operating parameters are adjusted according to the relationship between the current voltage value of the battery pack and the preset voltage value of the motor, so that the difference parameter between the motor output torque of the motor and the required torque value at different current voltage values ​​of the battery pack is less than the preset difference parameter.

[0015] In some embodiments, the motor operating parameter includes at least one of a duty cycle of a motor drive signal and a motor conduction angle.

[0016] In some embodiments, the controller is specifically configured to:

[0017] When the current voltage value of the battery pack is less than the preset voltage value of the motor, a signal is output to the motor to instruct the motor to increase the duty cycle of the motor drive signal and / or expand the motor conduction angle.

[0018] In some embodiments, the controller is configured to:

[0019] When the current voltage value of the battery pack is less than the preset voltage value of the motor, the required duty cycle of the motor is calculated based on the relationship between the current voltage value of the battery pack and the preset voltage value of the motor. When the required duty cycle is not greater than the preset duty cycle threshold, a signal is output to the motor to increase the duty cycle of the motor drive signal to the required duty cycle.

[0020] In some embodiments, when the required duty cycle is greater than a preset duty cycle threshold, a signal is output to the motor to increase the duty cycle of the motor drive signal to the preset duty cycle threshold, and then a signal is output to the motor to expand the motor conduction angle based on the difference between the required duty cycle and the preset duty cycle threshold.

[0021] In some embodiments, the controller is configured to:

[0022] When the current voltage value of the battery pack is less than the preset voltage value of the motor, a signal to increase the duty cycle of the motor drive signal is output to the motor until the duty cycle of the motor drive signal reaches a preset duty cycle threshold or the difference parameter between the motor output torque and the required torque value is less than a preset difference parameter.

[0023] In some embodiments, when the duty cycle of the motor drive signal reaches a preset duty cycle threshold and a difference parameter between the motor output torque and the required torque value is not less than a preset difference parameter, a signal for increasing the motor conduction angle is output to the motor.

[0024] In some embodiments, the preset motor voltage value is configured as a voltage of the motor when the battery pack provides a nominal voltage and the motor provides the required torque value.

[0025] In some embodiments, the difference parameter includes: a ratio of a difference between the motor output torque of the motor and the required torque value at a current voltage value to the required torque value, and the preset difference parameter is 20%.

[0026] An impact tool comprising:

[0027] an electric motor including a drive shaft rotating about a first axis and outputting torque via the drive shaft;

[0028] A battery pack, for supplying power to at least the motor;

[0029] Output shaft, used for outputting torque externally;

[0030] An impact mechanism, used for applying an impact force to the output shaft;

[0031] A controller, used for controlling the motor;

[0032] Wherein, the controller is configured as:

[0033] After the impact mechanism applies an impact force to the output shaft, the required torque value of the motor is determined, the preset impact cycle of the impact mechanism is matched according to the required torque value, and the motor operating parameters are adjusted according to the relationship between the current impact cycle of the impact mechanism and the preset impact cycle, so that the difference parameter between the motor output torque of the motor and the required torque value under different current voltages of the battery pack is less than the preset difference parameter.

[0034] In some embodiments, the motor operating parameter includes at least one of a duty cycle of a motor drive signal and a motor conduction angle.

[0035] In some embodiments, the controller is configured to:

[0036] When the current impact cycle of the impact mechanism is greater than the preset impact cycle, a signal is output to the motor to instruct the motor to increase the duty cycle of the motor drive signal and / or expand the motor conduction angle.

[0037] In some embodiments, the controller is configured to:

[0038] When the current impact cycle of the impact mechanism is greater than the preset impact cycle, the required duty cycle of the motor is calculated based on the relationship between the current impact cycle of the impact mechanism and the preset impact cycle; when the required duty cycle is not greater than the preset duty cycle threshold, a signal is output to the motor to increase the duty cycle of the motor drive signal to the required duty cycle.

[0039] In some embodiments, when the required duty cycle is greater than a preset duty cycle threshold, a signal is output to the motor to increase the duty cycle of the motor drive signal to the preset duty cycle threshold, and then a signal is output to the motor to expand the motor conduction angle based on the difference between the required duty cycle and the preset duty cycle threshold.

[0040] In some embodiments, the controller is configured to:

[0041] When the current impact cycle of the impact mechanism is greater than the preset impact cycle, a signal for increasing the duty cycle of the motor drive signal is output to the motor until the duty cycle of the motor drive signal reaches a preset duty cycle threshold or the difference parameter between the motor output torque and the required torque value is less than a preset difference parameter.

[0042] In some embodiments, when the duty cycle of the motor drive signal reaches a preset duty cycle threshold and a difference parameter between the motor output torque and the required torque value is not less than a preset difference parameter, a signal for increasing the motor conduction angle is output to the motor.

[0043] An impact tool comprising:

[0044] an electric motor including a drive shaft rotating about a first axis and outputting torque via the drive shaft;

[0045] A battery pack, for supplying power to at least the motor;

[0046] Output shaft, used for outputting torque externally;

[0047] An impact mechanism, used for applying an impact force to the output shaft;

[0048] A controller, used for controlling the motor;

[0049] Wherein, the controller is configured as:

[0050] After the impact mechanism applies an impact force to the output shaft, the ratio of the difference between the motor output torque and the required torque value to the required torque value is less than 20% under different current voltages of the battery pack.

[0051] An impact tool comprising:

[0052] an electric motor including a drive shaft rotating about a first axis and outputting torque via the drive shaft;

[0053] A battery pack, for supplying power to at least the motor;

[0054] Output shaft, used for outputting torque externally;

[0055] An impact mechanism, used for applying an impact force to the output shaft;

[0056] A controller, used for controlling the motor;

[0057] Wherein, the controller is configured as:

[0058] After the impact mechanism applies an impact force to the output shaft, the required torque value of the motor is determined, and the preset value of the first parameter value and the preset value of the second parameter value of the impact mechanism are matched according to the required torque value; the motor operating parameters are adjusted according to the relationship between the current first parameter value and the preset value of the first parameter value; the motor operating parameters adjusted by the first parameter value are corrected according to the relationship between the current second parameter value and the preset value of the second parameter value, so that the difference parameter between the motor output torque of the motor and the required torque value under different current voltages of the battery pack is less than the preset difference parameter.

[0059] In some embodiments, the controller is specifically configured as follows: the first parameter value is the voltage of the motor, and the second parameter value is the impact period of the impact mechanism.

[0060] The benefit of the present application is that: the controller is configured to: determine the required torque value of the motor after the impact mechanism applies impact force to the output shaft, match the motor preset voltage value according to the required torque value, and adjust the motor operating parameters according to the relationship between the current voltage value of the battery pack and the preset voltage value of the motor, so that the difference parameter between the motor output torque of the motor and the required torque value under different current voltage values ​​of the battery pack is less than the preset difference parameter. Therefore, when the voltage of the battery pack changes, the motor output torque will not change with the battery pack voltage, and the torque output can be stabilized, which provides a better user experience. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] Figure 1 is a schematic structural diagram of an impact tool according to an embodiment of the present application;

[0062] Figure 2 yes Figure 1 A cross-sectional view of the impact tool;

[0063] Figure 3 is a circuit diagram of an impact tool according to an embodiment of the present application;

[0064] Figure 4A control flow chart of an impact tool according to an embodiment of the present application;

[0065] Figure 5 A control flow chart of an impact tool according to another embodiment of the present application;

[0066] Figure 6 A control flow chart of an impact tool according to another embodiment of the present application;

[0067] Figure 7 A control flow chart of an impact tool according to another embodiment of the present application;

[0068] Figure 8 A control flow chart of an impact tool according to another embodiment of the present application;

[0069] Fig. 9 A control flow chart of an impact tool according to another embodiment of the present application;

[0070] Fig.10 This is a control flow chart of an impact tool according to another embodiment of the present application. DETAILED DESCRIPTION

[0071] 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.

[0072] 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.

[0073] 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.

[0074] 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 intermediary, and indirect connection refers to two parts or components being connected to at least one intermediary respectively, and the two parts or components being connected via the intermediary. In addition, "connect" and "couple" are not limited to physical or mechanical connections or couplings, and may include electrical connections or couplings.

[0075] 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).

[0076] 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.

[0077] 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.

[0078] 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.

[0079] In the present application, the terms “device”, “module” or “unit” may be implemented in the form of hardware or software to achieve specific functions.

[0080] 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.).

[0081] 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.

[0082] like Figure 1 and Figure 2 An impact tool of one embodiment of the present application is shown. The impact tool is an impact wrench 100. It can be understood that in other alternative embodiments, the impact tool can be equipped with different working accessories, and through these different working accessories, the impact tool can be, for example, an impact drill, an impact screwdriver, etc.

[0083] The impact wrench 100 includes a power supply. In the present embodiment, the power supply is a DC power supply 30. The DC power supply 30 is used to provide electrical energy to the impact wrench 100. The DC power supply 30 is a battery pack, and the battery pack cooperates with the corresponding power supply circuit to power the impact wrench 100. Those skilled in the art should understand that the power supply 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 achieve power supply to the corresponding components in the machine. In the present embodiment, the DC power supply is a battery pack, and the battery pack can specifically be a battery pack. The battery pack 30 will be used to replace the DC power supply below, but it cannot be used as a limitation of the present invention.

[0084] like Figure 1 to Figure 2 As shown, the impact wrench 100 includes a housing 11, a motor 12, an output mechanism 13, a transmission mechanism 14 and an impact mechanism 15. 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.

[0085] The output mechanism 13 includes an output shaft 131 for connecting a working accessory and driving the working accessory to rotate. A clamping assembly 132 is provided at the front end of the output shaft 131, which can clamp corresponding working accessories, such as screwdrivers, drill bits, sleeves, etc., when implementing different functions.

[0086] The output shaft 131 is used to output torque to operate the fastener, and the output shaft 131 rotates around the output axis. In this embodiment, the output axis is the second axis 102. In this embodiment, the first axis 101 coincides with the second axis 102. In other alternative embodiments, the second axis 102 is set at a certain angle to the first axis 101. In other alternative embodiments, the first axis 101 and the second axis 102 are parallel to each other but do not coincide.

[0087] The impact mechanism 15 is used to apply an impact force to the output shaft 131. The impact mechanism 15 includes a main shaft 151, an impact block 152 sleeved on the outer periphery of the main shaft 151, an anvil 153 and an elastic element 154 arranged at the front end of the impact block 152. Among them, the anvil 153 is connected to the output shaft 131. In this embodiment, the anvil 153 includes an anvil seat, and the output shaft 131 is formed at the front end of the anvil seat. It can be understood that the anvil seat and the output shaft 131 can be integrally formed or separately formed as independent parts.

[0088] The elastic element 154 provides a force for the impact block 152 to approach the anvil 153. In this embodiment, the elastic element 154 is a coil spring. A pair of first ball grooves with openings facing forward and extending backward in the front-to-back direction are also provided on the front end surface of the impact block 152. A pair of second ball grooves are also formed on the outer surface of the main shaft 151. The impact mechanism 15 also includes a rolling ball. The rolling ball spans the first ball groove and the second ball groove, thereby connecting the impact block 152 to the main shaft 151. In this embodiment, the rolling ball is a steel ball.

[0089] The housing 11 includes a motor housing 111 for accommodating the motor 12 and an output housing 112 for accommodating at least part of the output assembly 13, and the output housing 112 is connected to the front end of the motor housing 111. The housing 11 is also formed or connected with a grip portion 113 for user operation. The grip portion 113 and the motor housing 112 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 the power supply device 30.

[0090] The transmission mechanism 14 is disposed between the motor 12 and the impact mechanism 15, and is used to realize the transmission of power between the motor shaft 121 and the main shaft 151. In this embodiment, the transmission mechanism 14 adopts a planetary gear reduction. Because the working principle of the planetary gear reduction and the reduction generated by this transmission mechanism have been fully disclosed to professionals in this field, a detailed description is omitted here for the purpose of brevity of the specification.

[0091] During operation, when the impact wrench 100 is unloaded, the impact mechanism 15 does not impact, and the impact mechanism 15 plays a transmission role, transmitting the rotation of the motor 12 to the output shaft 131. When a load is applied to the impact tool 100, the rotation of the output shaft 131 is blocked. Due to the different load sizes, the output shaft 131 may reduce the speed or completely stop rotating. When the output shaft 131 completely stops rotating, the anvil 153 also stops rotating. Due to the circumferential limiting effect of the anvil 153 on the impact block 152, the impact block 152 also stops rotating, but the main shaft 151 continues to rotate, which causes the rolling ball to be squeezed and move along the ball track, thereby driving the impact block 152 to produce a backward displacement along the main shaft axis. At the same time, the elastic element 154 is squeezed until the anvil 153 is completely disengaged from the impact block 152. At this time, the main shaft 151 drives the impact block 152 to rotate at a certain speed, and the elastic element 154 rebounds axially. When the impact block 152 rotates to contact the anvil 153, an impact force is applied to the anvil 153. Under the action of this impact force, the output shaft 131 continues to rotate a certain angle to overcome the load, and then the output shaft 131 stops again, and the above process is repeated. Since the impact frequency is large enough, a relatively continuous impact force is generated on the output shaft 131, so that the working accessory continues to work.

[0092] like Figure 3 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.

[0093] like Figure 1-Figure 3As shown, the impact wrench 100 includes a control mechanism. The control mechanism includes a drive circuit 171 and a controller 17. The drive 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 battery pack 30 to the stator windings U, V, and W to drive the motor 12 to rotate. In one embodiment, the drive 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 the control signal from the controller 17 to change their respective conduction states, thereby changing the current loaded by the battery pack 30 on the stator windings U, V, and W of the motor 12. In one embodiment, the drive circuit 171 may be a three-phase bridge driver circuit including six controllable semiconductor power devices (e.g., field effect transistors (FET), bipolar junction transistors (BJT), insulated gate bipolar transistors (IGBT), etc.). It is understood that the above-mentioned switching elements may also be any other type of solid-state switches, such as insulated gate bipolar transistors (IGBT), bipolar junction transistors (BJT), etc.

[0094] 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 printed circuit board (PCB) and a flexible printed circuit (FPC). The controller 17 uses a dedicated control chip, for example, a single chip microcomputer, a microcontroller unit (MCU). The controller 17 specifically controls the on or off state of the switch element in the drive 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 it 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.

[0095] The impact wrench 100 further includes a power switch 16 and a switching portion 163. The power switch 16 is disposed on the grip portion 113 for user operation. The power switch 16 is used to control the power-on state of the motor 12. The switching portion 163 is disposed on the upper side of the main switch 16, and the switching portion 163 is configured to be operated to set the rotation direction of the motor 12 to a forward direction for tightening or screwing in a fastener or a reverse direction for loosening or screwing out a fastener. In this embodiment, the switching portion 163 is a switching switch.

[0096] In this embodiment, the power switch 16 is a travel switch, wherein the travel switch includes a speed adjustment portion 161 and a sliding rheostat 162 for operation. Therefore, the power switch 16 can also adjust the rotation speed of the motor 12. The rotation speed of the motor 12 is adjusted according to the trigger stroke of the speed adjustment portion 161. The signal output by the sliding rheostat 162 is different when the trigger stroke of the speed adjustment portion 161 is different.

[0097] The trigger stroke of the speed adjustment unit 161 is positively correlated with the duty cycle of the PWM signal of the motor 12, and the duty cycle of the PWM signal is positively correlated with the rotation speed of the motor 12. When the trigger stroke of the trigger switch is small, the duty cycle of the PWM signal is also small, and at this time, the rotation speed of the motor 12 is also small.

[0098] In some embodiments, the impact wrench 100 stores a mapping relationship between the trigger stroke of the speed adjustment unit 161 and the PWM signal. The mapping relationship may be linear or non-linear, which is not limited in the embodiments of the present application.

[0099] In some embodiments, the impact wrench 100 further includes a detection unit 18, and the detection unit 100 is used to detect motor parameters, and the motor parameters include at least one of the voltage of the motor and the current of the motor. The input end of the detection unit 100 is electrically connected to the motor 12, and the output end of the detection unit 100 is electrically connected to the controller 17, so that the controller 17 can obtain the motor parameters detected by the detection unit 18. In some embodiments, the detection unit 100 is used to detect the current of the motor, and the detection unit 100 includes a current sensing resistor, a Hall current sensor, or a mosfet (metal oxide semiconductor field effect transistor) on-resistance. In some embodiments, the detection unit 100 is used to detect the voltage of the motor, and the detection unit 100 includes one or more of an electromagnetic voltage transformer, a Hall voltage sensor, a voltage divider voltage sensor, an optical fiber voltage sensor, and a resistor divider.

[0100] Taking into account that the output torque of the impact tool is easily affected by the consumption of the DC power supply, in some embodiments, the controller 17 is configured as follows: after the impact mechanism 15 applies an impact force to the output shaft 131, the required torque value of the motor 12 is determined, the preset voltage value of the motor is matched according to the required torque value, and the motor operating parameters are adjusted according to the relationship between the current voltage value of the battery pack 30 and the preset voltage value of the motor, so that the difference parameter between the motor output torque and the required torque value of the motor 12 under different current voltage values ​​of the battery pack 30 is less than the preset difference parameter.

[0101] Among them, the required torque value of the motor 12 refers to the torque value that the motor 12 needs to reach when the impact tool is currently working normally. In this embodiment, the preset voltage value of the motor is configured as the voltage of the motor 12 when the battery pack 30 provides the nominal voltage and the motor 12 provides the required torque value. According to the output power formula: P = UI, P is the output power, U is the voltage value of the motor 12, and I is the current of the motor 12. When an impact occurs, the current magnitude is almost unchanged, so the voltage applied to the motor 12 is unchanged, and the output power of the motor 12 is basically unchanged, and the output torque is related to the output power, so the torque generated by the power is almost unchanged. Therefore, there is a correlation between the torque value and the voltage value of the motor 12, and the preset voltage value of the motor can be matched according to the required torque value.

[0102] The voltage of the motor 12 is provided by the battery pack 30, and the voltage of the motor 12 can be obtained by detecting the mother voltage at both ends of the motor 12. Optionally, the voltage of the motor 12 can also be obtained by detecting the phase voltage and then converting the mother voltage. There is a correlation between the current voltage of the battery pack 30 and the voltage of the motor 12. Therefore, in order to ensure that the voltage of the motor 12 can be a preset voltage value, the motor operating parameters can be adjusted according to the relationship between the current voltage value of the battery pack 30 and the preset voltage value of the motor. The motor operating parameters are parameters that can adjust the voltage of the motor 12. In this embodiment, the motor operating parameters include at least one of the duty cycle of the motor drive signal and the motor conduction angle. The voltage of the battery pack 30 is defined as Ua, and the voltage of the motor 12 is U=Ua*duty cycle of the motor drive signal. Therefore, in order to ensure that U remains unchanged, the duty cycle of the motor drive signal can be adjusted according to the change of Ua.

[0103] The preset difference parameter reflects the closeness between the motor output torque of the motor 12 and the required torque value. When the difference parameter between the motor output torque and the required torque value is less than the preset difference parameter, it means that the motor output torque is substantially the same as the required torque value. The type of the preset difference parameter can also be set according to the requirements, and the size of the preset difference parameter can be set according to different accuracy requirements, which is not specifically limited here. In some embodiments, the difference parameter includes: the ratio of the difference between the motor output torque of the motor and the required torque value at the current voltage value to the required torque value. In this embodiment, the preset difference parameter is 20%. In some embodiments, the preset difference parameter is 15%. In some embodiments, the preset difference parameter is 10%. In some other embodiments, the preset difference parameter includes a preset difference.

[0104] In some embodiments, the controller 17 is specifically configured to: when the current voltage value of the battery pack 30 is less than the preset voltage value of the motor, output a signal to the motor 12 instructing the motor 12 to increase the duty cycle of the motor drive signal and / or expand the motor conduction angle.

[0105] In the related art, the three-phase brushless BLDC motor is controlled by a 6-step commutation method, and optionally, it is a "two-phase conduction, three-phase, six-state" operation mode. In each working state, only two-phase windings are turned on. In the related art, the conduction angle of the three-phase brushless motor is fixed at 120 degrees. The way to increase the conduction angle is usually to increase the stator winding conduction phase within a 360° commutation cycle. For a three-phase motor, increasing the stator winding conduction phase means changing from two-phase winding commutation conduction to three-phase winding commutation conduction, that is, switching from two-two conduction to three-three conduction. Within a 360° commutation cycle, the longer the three-three conduction time, the greater the motor input power. When the current voltage value of the battery pack 30 is less than the preset voltage value of the motor, by increasing the duty cycle of the motor drive signal and / or expanding the motor conduction angle, the difference parameter between the motor output torque of the motor 12 and the required torque value is less than the preset difference parameter.

[0106] In some embodiments, the controller 17 is configured as follows: when the current voltage value of the battery pack 30 is less than the preset voltage value of the motor, the required duty cycle of the motor 12 is calculated according to the relationship between the current voltage value of the battery pack 30 and the preset voltage value of the motor, and when the required duty cycle is not greater than the preset duty cycle threshold, a signal is output to the motor 12 to increase the duty cycle of the motor drive signal to the required duty cycle. The required duty cycle refers to the duty cycle of the drive signal when the voltage of the motor 12 reaches the preset voltage value of the motor under the current voltage value of the battery pack 30, and the preset duty cycle threshold refers to the maximum value that the duty cycle of the drive signal of the motor 12 can reach. When the required duty cycle is not greater than the preset duty cycle threshold, increasing the duty cycle of the motor drive signal at this time can make the motor 12 the required duty cycle, thereby making the difference parameter between the motor output torque of the motor 12 and the required torque value less than the preset difference parameter.

[0107] In some embodiments, when the required duty cycle is greater than the preset duty cycle threshold, a signal is output to the motor 12 to increase the duty cycle of the motor drive signal to the preset duty cycle threshold, and then a signal is output to the motor 12 to expand the motor conduction angle based on the difference between the required duty cycle and the preset duty cycle threshold. Among them, when the required duty cycle is greater than the preset duty cycle threshold, it means that only increasing the duty cycle of the drive signal at this time cannot make the voltage of the motor 12 reach the preset voltage value, so at this time, the power of the motor 12 can be further increased to reach the preset voltage value by expanding the motor conduction angle. The larger the difference, the larger the conduction angle. The specific correspondence between the difference between the required duty cycle and the preset duty cycle threshold and the conduction angle can be set in advance. For example, the size of the conduction angle when the motor 12 is the preset voltage value under different differences can be tested, and then the specific correspondence between the two can be obtained by associating the two. Since the specific correspondence may vary according to different impact tools, the specific correspondence between the two is not specifically limited here.

[0108] In some embodiments, the controller 17 is configured to: when the current voltage value of the battery pack 30 is less than the preset voltage value of the motor, output a signal to the motor 12 to increase the duty cycle of the motor drive signal until the duty cycle of the motor drive signal reaches the preset duty cycle threshold or the difference parameter between the motor output torque and the required torque value is less than the preset difference parameter. Among them, when the current voltage value of the battery pack 30 is less than the preset voltage value of the motor, it means that the voltage of the motor 12 needs to be increased. At this time, the motor 12 is controlled to increase the duty cycle of the drive signal. When the difference parameter between the motor output torque and the required torque value is less than the preset difference parameter, it means that only the duty cycle of the drive signal needs to be increased to make the motor output torque and the required torque value basically the same. When the duty cycle of the motor drive signal reaches the preset duty cycle threshold, it means that the duty cycle of the motor drive signal can no longer be increased at this time, so the duty cycle of the motor drive signal is no longer increased.

[0109] In some embodiments, when the duty cycle of the motor drive signal reaches a preset duty cycle threshold and the difference parameter between the motor output torque and the required torque value is not less than the preset difference parameter, it means that the maximum power is output at this time, but the output torque still cannot reach the preset torque, that is, only increasing the duty cycle of the drive signal cannot make the motor output torque basically the same as the required torque value. Therefore, at this time, a signal to expand the motor conduction angle is output to the motor 12. By expanding the motor conduction angle, the voltage of the motor 12 is further increased to reach the preset voltage value, so that the motor output torque is basically the same as the required torque value.

[0110] In some embodiments, the controller 17 is configured to: determine the required torque value of the motor 12 after the impact mechanism 15 applies an impact force to the output shaft 131, match the preset impact cycle of the impact mechanism 15 according to the required torque value, and adjust the motor operating parameters according to the relationship between the current impact cycle of the impact mechanism 15 and the preset impact cycle, so that the difference parameter between the motor output torque and the required torque value of the motor 12 under different current voltages of the battery pack 30 is less than the preset difference parameter.

[0111] Among them, the impact cycle is the time interval between two consecutive impacts. The shorter the time between two impacts, the greater the torque provided. The faster the speed of the motor 12, the shorter the impact cycle. When the impact cycle remains basically unchanged, the output torque remains basically unchanged. The current impact cycle refers to the actual impact cycle of the impact mechanism 15 at present, and the preset impact cycle refers to the impact cycle that the impact mechanism 15 needs to reach. In this embodiment, the preset impact cycle is configured as the impact cycle required by the impact mechanism 15 when the battery pack 30 provides the nominal voltage and the motor 12 provides the required torque value. The motor operating parameters are parameters that can adjust the voltage of the motor 12. In this embodiment, the motor operating parameters include at least one of the duty cycle of the motor drive signal and the motor conduction angle.

[0112] Since the impact cycle and the torque of the motor 12 are correlated, the motor operating parameters can be adjusted according to the relationship between the current impact cycle of the impact mechanism 15 and the preset impact cycle, so that the difference parameter between the motor output torque and the required torque value of the motor 12 under the current voltage of different battery packs 30 is less than the preset difference parameter. Therefore, the motor output torque will not change with the voltage of the battery pack 30, the torque output is stable, and the user experience is better when using it.

[0113] In some embodiments, the impact cycles corresponding to different torques are measured in advance when the battery pack 30 is fully charged. The specific correspondence between the torque value and the impact cycle is obtained. The impact cycle here is a preset impact cycle corresponding to the motor output torque. When the required torque, that is, the required torque value, is set or detected according to the user, the corresponding preset impact cycle is called, and the motor operating parameters are adjusted so that the current impact cycle is basically the same as the preset impact cycle, so that the motor output torque of the motor 12 can be basically the same as the required torque value.

[0114] When the duty cycle of the motor drive signal is fixed, the greater the load of the output shaft 131, the smaller the rotation angle of the output shaft 131. The number of rotations of the drive shaft 121 of the motor 12 is related to the rotation angle of the output shaft 131. The commutation information of the motor 12 is related to the number of rotations of the drive shaft 121 of the motor 12. When an impact occurs, the load of the output shaft 131 changes, so the commutation information of the motor 12 changes. Among them, the commutation information of the motor 12 includes: at least one of the commutation starting point, the commutation end point, or the time required to complete each commutation. Therefore, in some embodiments, the current impact cycle of the impact mechanism 15 is obtained by detecting the change in the commutation time of the motor 12.

[0115] In some embodiments, the impact state of the impact mechanism 15 is determined by the current of the motor 12, and the current impact cycle of the impact mechanism 15 can be obtained by detecting the change in current. Whether an impact occurs is determined by the change in current during the impact, and the current impact cycle is obtained by the time interval between two consecutive impacts. Specifically, the current can be detected by any one of a current-sensing resistor, a Hall current sensor, or a mosfet (metal oxide semiconductor field effect transistor) on-resistance. In other alternative embodiments, by detecting various physical signals when the impact is generated, such as electrical signals, audio signals, etc., it is determined and collected, and then fed back to the controller 17 to determine that the impact mechanism 15 starts to impact the output shaft 131. In some embodiments, the detection unit 18 determines the demagnetization time by detecting the bus voltage, and determines that the impact mechanism 15 starts to impact the output shaft 131 by the demagnetization time. For professional and technical personnel in this field, it has been fully disclosed that the impact mechanism 15 enters the impact by the above method, that is, the impact mechanism 15 starts to apply impact force to the output shaft 131. Therefore, the above does not limit the substantive content of the present invention.

[0116] In some embodiments, the controller 17 is configured to: when the current impact cycle of the impact mechanism 15 is greater than the preset impact cycle, output a signal to the motor 12 to instruct the motor 12 to increase the duty cycle of the motor drive signal and / or expand the motor conduction angle. Among them, increasing the duty cycle of the motor drive signal and expanding the motor conduction angle can both increase the motor output torque. When the current impact cycle of the impact mechanism 15 is greater than the preset impact cycle, it means that the motor output torque is less than the required torque value. At this time, increasing the duty cycle of the motor drive signal and / or expanding the motor conduction angle can increase the motor output torque, thereby making the motor output torque substantially the same as the required torque value, thereby stabilizing the torque of the motor 12.

[0117] In some embodiments, the controller 17 is configured to: when the current impact cycle of the impact mechanism 15 is greater than the preset impact cycle, calculate the required duty cycle of the motor 12 according to the relationship between the current impact cycle of the impact mechanism 15 and the preset impact cycle, and when the required duty cycle is not greater than the preset duty cycle threshold, output a signal to the motor 12 to increase the duty cycle of the motor drive signal to the required duty cycle. The required duty cycle refers to the duty cycle of the drive signal of the motor 12 when the impact mechanism 15 reaches the preset impact cycle under the current voltage value of the battery pack 30, and the preset duty cycle threshold refers to the maximum value that the duty cycle of the drive signal of the motor 12 can reach. When the required duty cycle is not greater than the preset duty cycle threshold, increasing the duty cycle of the motor drive signal at this time can make the motor 12 the required duty cycle, thereby making the difference parameter between the motor output torque of the motor 12 and the required torque value less than the preset difference parameter.

[0118] In some embodiments, when the battery pack 30 is fully charged, the duty cycle of the motor drive signal corresponding to different impact cycles is measured in advance. A specific correspondence between the impact cycle and the duty cycle of the motor drive signal is obtained. The duty cycle of the motor drive signal here is the required duty cycle corresponding to the preset impact cycle. Therefore, when the relationship between the current impact cycle and the preset impact cycle of the impact mechanism 15 is obtained, the required duty cycle of the motor 12 can be calculated according to the corresponding relationship. By adjusting the duty cycle of the motor drive signal so that the current impact cycle is basically the same as the preset impact cycle, the motor output torque of the motor 12 can be made basically the same as the required torque value.

[0119] In some embodiments, when the required duty cycle is greater than the preset duty cycle threshold, a signal for increasing the duty cycle of the motor drive signal to the preset duty cycle threshold is output to the motor 12, and then a signal for increasing the motor conduction angle is output to the motor 12 based on the difference between the required duty cycle and the preset duty cycle threshold. When the required duty cycle is greater than the preset duty cycle threshold, it means that only increasing the duty cycle of the drive signal cannot make the voltage of the motor 12 reach the preset voltage value, so at this time, the voltage of the motor 12 can be further increased by increasing the motor conduction angle to reach the preset voltage value.

[0120] In some embodiments, the controller 17 is configured to: when the current impact cycle of the impact mechanism 15 is greater than the preset impact cycle, output a signal to the motor 12 to increase the duty cycle of the motor drive signal until the duty cycle of the motor drive signal reaches the preset duty cycle threshold or the difference parameter between the motor output torque and the required torque value is less than the preset difference parameter. Wherein, when the current impact cycle of the impact mechanism 15 is greater than the preset impact cycle, it means that the torque of the motor 12 needs to be increased. At this time, the motor 12 is controlled to increase the duty cycle of the motor drive signal. When the difference parameter between the motor output torque and the required torque value is less than the preset difference parameter, it means that the output torque has been stabilized. At the same time, it is only necessary to increase the duty cycle of the motor drive signal to make the motor output torque and the required torque value basically the same, and there is no need to continue to increase the duty cycle of the motor drive signal. When the duty cycle of the motor drive signal reaches the preset duty cycle threshold, it means that the duty cycle of the motor drive signal can no longer be increased, so the duty cycle of the motor drive signal is no longer increased.

[0121] In some embodiments, when the duty cycle of the motor drive signal reaches a preset duty cycle threshold and the difference parameter between the motor output torque and the required torque value is not less than the preset difference parameter, it means that only increasing the duty cycle of the motor drive signal cannot make the motor output torque basically the same as the required torque value. Therefore, at this time, a signal to expand the motor conduction angle is output to the motor 12. By expanding the motor conduction angle, the voltage of the motor 12 is further increased to reach the preset voltage value, so that the motor output torque is basically the same as the required torque value.

[0122] In some embodiments, the controller 17 is configured to: determine the required torque value of the motor 12 after the impact mechanism 15 applies an impact force to the output shaft 131, match the preset value of the first parameter value and the preset value of the second parameter value of the impact mechanism 15 according to the required torque value, adjust the motor operating parameters according to the relationship between the current first parameter value and the preset value of the first parameter value, and correct the motor operating parameters adjusted by the first parameter value according to the relationship between the current second parameter value and the preset value of the second parameter value, so that the difference parameter between the motor output torque and the required torque value of the motor 12 under different current voltages of the battery pack 30 is less than the preset difference parameter.

[0123] Among them, the first parameter value and the second parameter value are parameters related to the torque value of the motor 12, and the preset value of the first parameter value is the first parameter value of the impact mechanism 15 when the motor 12 outputs the required torque value. The preset value of the second parameter value is the second parameter value of the impact mechanism 15 when the motor 12 outputs the required torque value. Therefore, the motor operating parameters are first adjusted according to the relationship between the current first parameter value and the preset value of the first parameter value, and then the motor operating parameters adjusted by the first parameter value are corrected according to the relationship between the current second parameter value and the preset value of the second parameter value, so that the motor output torque can be basically the same as the required torque value, so that the motor output torque of the motor 12 is basically the same under different current voltages of the battery pack 30, and the torque output can be stabilized.

[0124] In some embodiments, the controller 17 is specifically configured as follows: the first parameter value is the voltage of the motor 12, and the second parameter value is the impact cycle of the impact mechanism 15. Since the voltage can be detected in real time, but the impact cycle needs to last for a period of time before it can be detected, by first adjusting the output torque of the motor 12 to near the required torque value according to the relationship between the current value of the voltage of the motor 12 and the preset value, and then making the difference parameter between the output torque of the motor 12 and the required torque value less than the preset difference parameter according to the relationship between the current value of the impact cycle and the preset value, the motor output torque can be quickly adjusted to near the required torque value, and then the motor output torque can be stabilized to be basically the same as the required torque value, so that the motor output torque will not change with the voltage of the battery pack 30, and the torque output can be stabilized, and the user experience is better.

[0125] refer to Figure 4 The control flow chart for the impact tool in the above embodiment shown specifically includes the following steps:

[0126] S101 : Determine a required torque value of a motor.

[0127] S102, matching a preset voltage value of the motor according to the required torque value.

[0128] S103, adjusting the motor operating parameters according to the relationship between the current voltage value of the battery pack and the preset voltage value of the motor, so that the difference parameter between the motor output torque and the required torque value of the motor under different current voltage values ​​of the battery pack is less than the preset difference parameter.

[0129] In some embodiments, Figure 5 As shown, the control flow chart of the impact tool in the above embodiment specifically includes the following steps:

[0130] S111. Determine the required torque value of the motor.

[0131] S112, matching the preset voltage value of the motor according to the required torque value.

[0132] S113, determining whether the current voltage value of the battery pack is less than the preset voltage value of the motor. If yes, proceed to step S114, if no, continue to execute step S113.

[0133] S114. Calculate the required duty cycle of the motor according to the relationship between the current voltage value of the battery pack and the preset voltage value of the motor.

[0134] S115: Determine whether the required duty cycle is greater than a preset duty cycle threshold. If not, execute step S116; if so, execute step S117.

[0135] S116, outputting a signal to the motor to increase the duty cycle of the motor drive signal to the required duty cycle, so that the difference parameter between the motor output torque of the motor and the required torque value at different current voltage values ​​of the battery pack is less than a preset difference parameter.

[0136] S117, output a signal to the motor to increase the duty cycle of the motor drive signal to a preset duty cycle threshold, and then output a signal to the motor to expand the motor conduction angle based on the difference between the required duty cycle and the preset duty cycle threshold, so that the difference parameter between the motor output torque of the motor and the required torque value at different current voltage values ​​of the battery pack is less than the preset difference parameter.

[0137] In some embodiments, Figure 6 As shown, the control flow chart of the impact tool in the above embodiment specifically includes the following steps:

[0138] S121. Determine the required torque value of the motor.

[0139] S122, matching the preset voltage value of the motor according to the required torque value.

[0140] S123, determine whether the current voltage value of the battery pack is less than the preset voltage value of the motor. If yes, proceed to step S124, if not, continue to execute step S123.

[0141] S124. Output a signal for increasing the duty cycle of the motor drive signal to the motor.

[0142] S1251. Determine whether the duty cycle of the motor drive signal reaches a preset duty cycle threshold.

[0143] S1252, determining whether a difference parameter between the motor output torque of the motor and the required torque value is less than a preset difference parameter.

[0144] If the duty cycle of the motor drive signal reaches the preset duty cycle threshold and the difference parameter between the motor output torque and the required torque value is not less than the preset difference parameter, execute step S126; if the difference parameter between the motor output torque and the required torque value is less than the preset difference parameter, end the process.

[0145] S126. Output a signal to the motor to enlarge the motor conduction angle so that the difference parameter between the motor output torque and the required torque value of the motor under different current voltage values ​​of the battery pack is less than a preset difference parameter.

[0146] In some embodiments, Figure 7 As shown, the control flow chart of the impact tool in the above embodiment specifically includes the following steps:

[0147] S201, determining a required torque value of a motor.

[0148] S202: Matching a preset impact cycle of the impact mechanism according to the required torque value.

[0149] S203, adjusting the motor operating parameters according to the relationship between the current impact cycle of the impact mechanism and the preset impact cycle, so that the difference parameter between the motor output torque of the motor and the required torque value under different current voltages of the battery pack is less than the preset difference parameter.

[0150] In some embodiments, Figure 8 As shown, the control flow chart of the impact tool in the above embodiment specifically includes the following steps:

[0151] S211. Determine the required torque value of the motor.

[0152] S212: Matching a preset impact cycle of the impact mechanism according to the required torque value.

[0153] S213, determining whether the current impact cycle of the impact mechanism is greater than the preset impact cycle. If yes, proceed to step S214, if no, continue to execute step S213.

[0154] S214: Calculate the required duty cycle of the motor according to the relationship between the current impact cycle of the impact mechanism and the preset impact cycle.

[0155] S215: Determine whether the required duty cycle is greater than a preset duty cycle threshold. If not, execute step S216; if so, execute step S217.

[0156] S216, outputting a signal to the motor to increase the duty cycle of the motor drive signal to the required duty cycle, so that the difference parameter between the motor output torque of the motor and the required torque value at different current voltage values ​​of the battery pack is less than a preset difference parameter.

[0157] S217, output a signal to the motor to increase the duty cycle of the motor drive signal to a preset duty cycle threshold, and then output a signal to the motor to expand the motor conduction angle based on the difference between the required duty cycle and the preset duty cycle threshold, so that the difference parameter between the motor output torque of the motor and the required torque value under different current voltage values ​​of the battery pack is less than the preset difference parameter.

[0158] In some embodiments, Fig. 9 As shown, the control flow chart of the impact tool in the above embodiment specifically includes the following steps:

[0159] S221. Determine the required torque value of the motor.

[0160] S222: Matching a preset impact cycle of the impact mechanism according to the required torque value.

[0161] S223, determining whether the current impact cycle of the impact mechanism is greater than the preset impact cycle. If yes, proceed to step S224, if no, continue to execute step S223.

[0162] S224. Output a signal for increasing the duty cycle of the motor drive signal to the motor.

[0163] S2251. Determine whether the duty cycle of the motor drive signal reaches a preset duty cycle threshold.

[0164] S2252: Determine whether a difference parameter between the motor output torque of the motor and the required torque value is less than a preset difference parameter.

[0165] If the duty cycle of the motor drive signal reaches the preset duty cycle threshold and the difference parameter between the motor output torque and the required torque value is not less than the preset difference parameter, execute step S226; if the difference parameter between the motor output torque and the required torque value is less than the preset difference parameter, end the process; if the duty cycle of the motor drive signal does not reach the preset duty cycle threshold and the difference parameter between the motor output torque and the required torque value is not less than the preset difference parameter, continue to execute step S224.

[0166] S226, outputting a signal to the motor to expand the motor conduction angle so that the difference parameter between the motor output torque and the required torque value at different current voltage values ​​of the battery pack is less than a preset difference parameter.

[0167] refer to Fig.10 The control flow chart for the impact tool in the above embodiment shown specifically includes the following steps:

[0168] S301 , determining a required torque value of a motor.

[0169] S302 , matching a preset value of a first parameter value and a preset value of a second parameter value of the impact mechanism according to the required torque value.

[0170] S303: Adjust the motor operating parameters according to the relationship between the current first parameter value and the preset value of the first parameter value.

[0171] S304. Correct the motor operating parameters adjusted by the first parameter value according to the relationship between the current second parameter value and the preset value of the second parameter value, so that the difference parameter between the motor output torque of the motor and the required torque value under different current voltages of the battery pack is less than the preset difference parameter.

[0172] 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 impact tool, characterized in that: include: an electric motor including a drive shaft rotating about a first axis and outputting torque via the drive shaft; A battery pack, for supplying power to at least the motor; Output shaft, used for outputting torque externally; An impact mechanism, used for applying an impact force to the output shaft; A controller, used for controlling the motor; Wherein, the controller is configured as: After the impact mechanism applies an impact force to the output shaft, the required torque value of the motor is determined, the preset voltage value of the motor is matched according to the required torque value, and the motor operating parameters are adjusted according to the relationship between the current voltage value of the battery pack and the preset voltage value of the motor, so that the difference parameter between the motor output torque of the motor and the required torque value at different current voltage values ​​of the battery pack is less than the preset difference parameter.

2. The impact tool according to claim 1, characterized in that The motor operation parameter includes at least one of a duty cycle of a motor drive signal and a motor conduction angle.

3. The impact tool according to claim 2, characterized in that The controller is specifically configured as follows: When the current voltage value of the battery pack is less than the preset voltage value of the motor, a signal is output to the motor to instruct the motor to increase the duty cycle of the motor drive signal and / or expand the motor conduction angle.

4. The impact tool according to claim 3, characterized in that The controller is configured to: When the current voltage value of the battery pack is less than the preset voltage value of the motor, the required duty cycle of the motor is calculated based on the relationship between the current voltage value of the battery pack and the preset voltage value of the motor. When the required duty cycle is not greater than the preset duty cycle threshold, a signal is output to the motor to increase the duty cycle of the motor drive signal to the required duty cycle.

5. The impact tool according to claim 3, characterized in that: When the required duty cycle is greater than a preset duty cycle threshold, a signal is output to the motor to increase the duty cycle of the motor drive signal to the preset duty cycle threshold, and then a signal is output to the motor to expand the motor conduction angle based on the difference between the required duty cycle and the preset duty cycle threshold.

6. The impact tool according to claim 3, characterized in that The controller is configured to: When the current voltage value of the battery pack is less than the preset voltage value of the motor, a signal to increase the duty cycle of the motor drive signal is output to the motor until the duty cycle of the motor drive signal reaches a preset duty cycle threshold or the difference parameter between the motor output torque and the required torque value is less than a preset difference parameter.

7. The impact tool according to claim 3, characterized in that When the duty cycle of the motor drive signal reaches a preset duty cycle threshold and a difference parameter between the motor output torque and the required torque value is not less than a preset difference parameter, a signal for increasing the motor conduction angle is output to the motor.

8. The impact tool according to any one of claims 1 to 7, characterized in that The preset motor voltage value is configured as a voltage of the motor when the battery pack provides a nominal voltage and the motor provides the required torque value.

9. The impact tool according to any one of claims 1 to 7, characterized in that: The difference parameter includes: a ratio of a difference between the motor output torque of the motor and the required torque value at a current voltage value to the required torque value, and the preset difference parameter is 20%.

10. An impact tool, characterized in that: include: an electric motor including a drive shaft rotating about a first axis and outputting torque via the drive shaft; A battery pack, for supplying power to at least the motor; Output shaft, used for outputting torque externally; An impact mechanism, used for applying an impact force to the output shaft; A controller, used for controlling the motor; Wherein, the controller is configured as: After the impact mechanism applies an impact force to the output shaft, the required torque value of the motor is determined, the preset impact cycle of the impact mechanism is matched according to the required torque value, and the motor operating parameters are adjusted according to the relationship between the current impact cycle of the impact mechanism and the preset impact cycle, so that the difference parameter between the motor output torque of the motor and the required torque value under different current voltages of the battery pack is less than the preset difference parameter.

11. The impact tool according to claim 10, characterized in that The motor operation parameter includes at least one of a duty cycle of a motor drive signal and a motor conduction angle.

12. The impact tool according to claim 11, characterized in that The controller is configured to: When the current impact cycle of the impact mechanism is greater than the preset impact cycle, a signal is output to the motor to instruct the motor to increase the duty cycle of the motor drive signal and / or expand the motor conduction angle.

13. The impact tool according to claim 12, characterized in that The controller is configured to: When the current impact cycle of the impact mechanism is greater than the preset impact cycle, the required duty cycle of the motor is calculated based on the relationship between the current impact cycle of the impact mechanism and the preset impact cycle; when the required duty cycle is not greater than the preset duty cycle threshold, a signal is output to the motor to increase the duty cycle of the motor drive signal to the required duty cycle.

14. The impact tool according to claim 12, characterized in that When the required duty cycle is greater than a preset duty cycle threshold, a signal is output to the motor to increase the duty cycle of the motor drive signal to the preset duty cycle threshold, and then a signal is output to the motor to expand the motor conduction angle based on the difference between the required duty cycle and the preset duty cycle threshold.

15. The impact tool according to claim 12, characterized in that The controller is configured to: When the current impact cycle of the impact mechanism is greater than the preset impact cycle, a signal for increasing the duty cycle of the motor drive signal is output to the motor until the duty cycle of the motor drive signal reaches a preset duty cycle threshold or the difference parameter between the motor output torque and the required torque value is less than a preset difference parameter.

16. The impact tool according to claim 12, characterized in that When the duty cycle of the motor drive signal reaches a preset duty cycle threshold and a difference parameter between the motor output torque and the required torque value is not less than a preset difference parameter, a signal for increasing the motor conduction angle is output to the motor.

17. An impact tool, characterized in that: include: an electric motor including a drive shaft rotating about a first axis and outputting torque via the drive shaft; A battery pack, for supplying power to at least the motor; Output shaft, used for outputting torque externally; An impact mechanism, used for applying an impact force to the output shaft; A controller, used for controlling the motor; Wherein, the controller is configured as: After the impact mechanism applies an impact force to the output shaft, the ratio of the difference between the motor output torque and the required torque value to the required torque value is less than 20% under different current voltages of the battery pack.

18. An impact tool, characterized in that: include: an electric motor including a drive shaft rotating about a first axis and outputting torque via the drive shaft; A battery pack, for supplying power to at least the motor; Output shaft, used for outputting torque externally; An impact mechanism, used for applying an impact force to the output shaft; A controller, used for controlling the motor; Wherein, the controller is configured as: After the impact mechanism applies an impact force to the output shaft, the required torque value of the motor is determined, and the preset value of the first parameter value and the preset value of the second parameter value of the impact mechanism are matched according to the required torque value; the motor operating parameters are adjusted according to the relationship between the current first parameter value and the preset value of the first parameter value; the motor operating parameters adjusted by the first parameter value are corrected according to the relationship between the current second parameter value and the preset value of the second parameter value, so that the difference parameter between the motor output torque of the motor and the required torque value under different current voltages of the battery pack is less than the preset difference parameter.

19. The impact tool according to claim 18, characterized in that The controller is specifically configured as follows: the first parameter value is the voltage of the motor, and the second parameter value is the impact period of the impact mechanism.

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