Impact tool and electric tool

Abstract

The invention provides an impact tool which can stop or decelerate a motor even if the impact tool is in position before starting striking. An electric tool 1 as an impact tool is provided with: a motor 20; an impact mechanism driven by the motor 20; a current measuring unit that measures a motor current; a rotational speed measuring unit that detects the number of revolutions of the motor; and a control unit 40 that controls the motor. The control unit (40) has an in-position determination mode configured so as to determine whether or not the screw is in position on the basis of the measured motor current and motor revolution at any point in time before and after the start of striking by the striking mechanism during a screw fastening operation under a plurality of different operation conditions, and to determine whether or not the screw is in position on the basis of the measured motor current and motor revolution at any point in time after the start of striking by the striking mechanism. After the screw is determined to be in position, the motor is stopped or decelerated.

Description

Technical Field

[0001] The invention relates to an impact tool and an electric tool. Background Art

[0002] Patent Document 1 listed below discloses that in-position determination is performed based on electric current.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent No. 6984742 Summary of the invention

[0006] Problems to be solved by the invention

[0007] In the technology of patent document 1, the motor cannot be stopped or decelerated when it is already in position before the impact mechanism starts hitting. In addition, since the position determination is performed based on the current, it is possible to over-tighten or under-tighten, resulting in poor workability.

[0008] The present invention solves at least one of the following problems 1 to 3. Problem 1: Provide an impact tool that can stop or decelerate a motor even when the tool is already in position before striking. Problem 2: Provide an electric tool with good workability. Problem 3: Provide an electric tool that can be controlled based on the amount of work.

[0009] Technical means of solving problems

[0010] A certain aspect of the present invention is an impact tool. The impact tool comprises: a motor; an impact mechanism driven by the motor; a current measuring unit measuring the current of the motor; a rotation speed measuring unit detecting the rotation speed of the motor; and a control unit controlling the motor, wherein the impact tool is characterized in that the control unit has a position determination mode, wherein the position determination mode is configured to determine whether the screw is in place based on the measured current of the motor and the rotation speed of the motor at any time point before and after the impact mechanism starts striking in a screw tightening operation under multiple different operating conditions, and stop or decelerate the motor after determining that the screw is in place.

[0011] Another aspect of the present invention is an electric tool. The electric tool includes: a motor; and a control unit that controls the motor, and the electric tool is characterized in that: the control unit has a screw tightening depth control mode, and the screw tightening depth control mode is configured to estimate the screw tightening depth relative to the object material based on the measured state quantity of the electric tool, and control the motor based on the estimated screw tightening depth and a set value set by a setting unit, and the setting unit is configured to be able to set multiple screw tightening depths including a first screw tightening depth before the screw is positioned on the object material, and a second screw tightening depth different from the first screw tightening depth as the set value.

[0012] Another aspect of the present invention is an electric tool. The electric tool includes: a motor; a current measuring unit for measuring the current of the motor; a rotation speed measuring unit for detecting the rotation speed of the motor; and a control unit for controlling the motor, wherein the electric tool is characterized in that the control unit has a processing amount estimation mode, wherein the processing amount estimation mode is configured to estimate the amount of irreversible processing on a target material, i.e., the processing amount, based on the measured current of the motor and the rotation speed of the motor, and control the motor based on the estimated processing amount.

[0013] Effects of the Invention

[0014] According to the present invention, at least one of the above-mentioned problems 1 to 3 can be solved. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] [ Figure 1 ] is a right side view of the electric tool 1 according to embodiment 1 of the present invention.

[0016] [ Figure 2 ] is a right side cross-sectional view of the electric tool 1.

[0017] [ Figure 3 ] is a circuit block diagram of the electric tool 1.

[0018] [ Figure 4 ]yes Figure 3 Functional block diagram of the control unit 40.

[0019] [ Figure 5 ] is a control flow chart of the control unit 40 in the stopped state.

[0020] [ Figure 6 ] is a control flow chart of the control unit 40 in the operating state.

[0021] [ Figure 7 ] (A) to (F) are schematic cross-sectional views showing the progress of screw tightening work on the target material. (G) Figure 7(A) to (F) are graphs showing time changes in the current of the motor 20, the number of revolutions of the motor 20, and the amount of screw head lifting during the screw tightening operation.

[0022] [ Figure 8 ] is a graph showing the correlation between the current and the number of revolutions of the motor 20 of the electric tool 1 and the amount of screw head lifting.

[0023] [ Fig. 9 ] is a conceptual diagram showing the structure of a neural network for estimating the screw head lifting amount of the electric tool 1.

[0024] [ Fig.10 ] is related to Figure 7 (G) The same graph is a graph showing that the time series data of the current and the number of revolutions of the motor 20 from time tn to time t is used as input to estimate the screw head lifting amount at time t.

[0025] [ Fig.11 ] is in Fig.10 The graph is a graph obtained by adding the estimated value of the screw head floating amount to the graph.

[0026] [ Fig.12 ] is a functional block diagram of the control unit 140 of the electric tool according to embodiment 2 of the present invention.

[0027] [ Fig.13 ] is a control flow chart of the control unit 140 in the operating state.

[0028] [ Fig.14 ] is a flow chart of the processing volume calculation of the control unit 140.

[0029] [ Fig.15 ] is a conceptual diagram showing an example of a table used in estimating the processing amount before the start of striking.

[0030] [ Fig.16 ] is a conceptual diagram showing an example of a table used in estimating the processing amount after the start of striking.

[0031] [ Fig.17 ] is a graph showing the relationship between the product of the current and the number of revolutions of the motor 20 and the amount of screw head lifting for two types of screws.

[0032] [ Fig.18 ] is to indicate Fig.17 A graph of the average curve of the data for the two screws. DETAILED DESCRIPTION

[0033] (Implementation Method 1) Figures 1 to 11 The present invention relates to an electric tool 1 according to a first embodiment of the present invention. The electric tool 1 is a working machine, specifically, an impact tool (impact screwdriver). Figure 1and Figure 2 As shown in FIG. 1 , mutually orthogonal front-rear directions and up-down directions of the electric power tool 1 are defined. The front-rear direction is a direction parallel to the motor shaft 21 .

[0034] like Figure 1 and Figure 2 As shown, the electric tool 1 has a housing 10. The housing 10 is, for example, a resin molded body having a left-right two-part structure. The housing 10 includes a motor housing portion 11, a handle portion 12, and a battery pack mounting portion 13.

[0035] The motor housing portion 11 is a cylindrical portion whose central axis is substantially parallel to the front-to-back direction. The upper end of the handle portion 12 is connected to the middle portion of the motor housing portion 11 in the front-to-back direction and extends downward from the middle portion. The battery pack installation portion 13 is provided at the lower end of the handle portion 12 and can be detachably installed with a battery pack 17. The power tool 1 operates using the power of the battery pack 17.

[0036] The electric tool 1 includes a tail cover 14 connected to and covering the opening at the rear side of the motor housing portion 11. The tail cover 14 is fixed to the motor housing portion 11 by screws or the like.

[0037] The electric tool 1 includes a hammer case 18 connected to the front portion of the motor housing portion 11. The hammer case 18 is made of metal, for example, and is held by the motor housing portion 11 and extends forward from the motor housing portion 11.

[0038] The power tool 1 has a trigger switch 15 at the upper end of the handle 12 for the user to switch the motor 20 between driving and stopping. The power tool 1 has a forward / reverse switch 16 near the boundary between the motor housing 11 and the handle 12 for the user to switch the motor 20 between forward and reverse rotation.

[0039] The electric tool 1 includes a first control board 35 in the battery pack installation portion 13. The first control board 35 is equipped with a control unit 40 (eg, a microcomputer) for controlling the driving of the motor 20. Figure 3 The electric tool 1 has an operation panel 19 on the front upper surface of the battery pack installation portion 13. The operation panel 19 has Figure 3 The display unit 46, the control mode switching switch 47, and the threshold setting device 48 are shown.

[0040] The working machine 1 includes a motor 20 , a speed reduction mechanism 28 , a main shaft 29 , a rotary striking mechanism 30 as an impact mechanism, and a fan 34 inside the motor housing portion 11 and the hammer case 18 .

[0041] The motor 20 is an inner rotor type brushless motor, and has a motor shaft 21 parallel to the front-rear direction. The motor 20 includes a rotor 22 , a stator core 23 , a stator coil 24 , a front insulator 25 , and a rear insulator 26 .

[0042] The rotor 22 is provided around the motor shaft 21, and rotates integrally with the motor shaft 21. The stator core 23, the stator coil 24, the front insulator 25, and the rear insulator 26 constitute a stator of the electric tool 1.

[0043] The stator core 23 is provided on the radially outer side of the rotor 22. The stator coil 24 is provided on the stator core 23. The front insulator 25 is provided on the front part of the stator core 23. The rear insulator 26 is provided on the rear part of the stator core 23. The front insulator 25 and the rear insulator 26 are, for example, resin molded bodies, and insulate the stator core 23 from the stator coil 24.

[0044] A second control board 36 is mounted on the front portion of the front insulator 25. The second control board 36 carries a magnetic sensor 50 (eg, Hall integrated circuit (IC)) for detecting the rotation position of the motor 20. Figure 3 ), or an inverter circuit 38 ( Figure 3 ).

[0045] The speed reduction mechanism 28 reduces the speed of the rotation of the motor 20 and transmits the speed reduction to the main shaft 29. The main shaft 29 drives the rotary striking mechanism 30. The rotary striking mechanism 30 is an output part of the electric tool 1 and is driven by the motor 20.

[0046] The rotary striking mechanism 30 includes a spring 31, a hammer 32, and an anvil 33. A top tool such as a drill bit (not shown) is held on the anvil 33. The hammer 32 is engaged with the main shaft 29 in a cam manner and is urged forward by the spring 31. The hammer 32 driven by the main shaft 29 rotates and strikes the anvil 33. The structure and operation of the rotary striking mechanism 30 are well known, so further detailed description is omitted.

[0047] The fan 34 is attached to the motor shaft 21 at the rear of the rotor 22 , rotates integrally with the motor shaft 21 , and generates cooling air for cooling the motor 20 and the like.

[0048] Figure 3 1 is a circuit block diagram of the electric tool 1. The electric tool 1 includes an inverter circuit 38, a resistor 39, a control unit 40, a current detection circuit 41, a battery voltage detection circuit 42, a control power supply circuit 43, a control power voltage detection circuit 44, a rotor position detection circuit 45, a display unit 46, a control mode switching switch 47, a threshold setting device 48, a drive signal output circuit 49, and a magnetic sensor 50.

[0049] The inverter circuit 38 includes six switching elements Q1 to Q6 such as field-effect transistors (FET) connected in a three-phase bridge connection. The resistor 39 is provided on the path of the current (hereinafter referred to as "motor current") flowing through the motor 20.

[0050] The control unit 40 is, for example, a microcomputer (microcontroller), and controls the overall operation of the electric tool 1. The current detection circuit 41 detects the motor current using the voltage of the resistor 39 and sends the result to the control unit 40. The current detection circuit 41 and the resistor 39 constitute a current measuring unit.

[0051] The battery voltage detection circuit 42 detects the output voltage of the battery pack 17 (hereinafter referred to as “battery voltage”), and sends it to the control unit 40. The control power supply circuit 43 converts the battery voltage into a power supply voltage for the control unit 40, etc., and supplies it to the control unit 40, etc. The control power supply voltage detection circuit 44 detects the output voltage of the control power supply circuit 43, and sends it to the control unit 40.

[0052] The rotor position detection circuit 45 detects the rotation position (rotor rotation position) of the motor 20 using the output signal of the magnetic sensor 50, and sends it to the control unit 40. The control unit 40 detects the rotation speed (hereinafter referred to as "motor rotation speed") of the motor 20 using the output signal of the rotor position detection circuit 45. The rotor position detection circuit 45, the magnetic sensor 50 and the control unit 40 constitute a rotation speed measurement unit.

[0053] The display unit 46 displays the current threshold value (set value) or control mode. The control mode switching switch 47 is, for example, a tactile switch, and is an operating unit for the user to switch between the validity and invalidity of the processing volume control mode described later. The threshold setting device 48 is a device (setting unit) for setting the threshold value (set value) described later in the processing volume control mode. The threshold setting device 48 is, for example, a switch (button) provided on the operation panel 19. As another example, the threshold setting device 48 may be a dial provided separately from the operation panel 19, or may be a wireless communication device for receiving a threshold value through wireless communication with an external device such as a smartphone.

[0054] The drive signal output circuit 49 applies a drive signal, such as a pulse-width modulation (PWM) signal, to each gate of the switching element Q1 to the switching element Q6 of the inverter circuit 38 according to the control of the control unit 40. The magnetic sensor 50 outputs a signal corresponding to the rotation position of the motor 20 to the rotor position detection circuit 45.

[0055] The control unit 40 controls the on and off of the switching elements Q1 to Q6 via the drive signal output circuit 49 according to the operation of the trigger switch 15, the state of the forward and reverse switching switch 16, the validity or invalidity of the processing amount control mode, and the threshold value in the processing amount control mode, thereby controlling the drive of the motor 20.

[0056] Figure 4 yes Figure 3 Functional block diagram of the control unit 40. Figure 4 Each block shown is a function of the control unit 40 and does not mean that there is a hardware entity. In addition, "NN" in the figure means a neural network.

[0057] The control unit 40 includes: a rotation speed calculation unit 51, a data storage unit 52, a learning completion model 53, a motor output setting unit 54, an output stability determination unit 55, a neural network operation unit 56 (hereinafter referred to as "NN operation unit 56"), a threshold setting unit 57, a comparator 58, a control mode setting unit 59, an AND gate 60, and a motor control unit 61.

[0058] The rotation number calculation unit 51 calculates the motor rotation speed using the reception signal from the rotor position detection circuit 45. In addition, the "rotation number" in the drawings refers to the number of rotations of the motor 20 per unit time (hereinafter "motor rotation number"), that is, the motor rotation speed.

[0059] The data storage unit 52 stores the motor rotation speed calculated by the rotation speed calculation unit 51 and the motor current received from the current detection circuit 41 , that is, the measured values ​​of the motor rotation speed and the motor current.

[0060] The learned model 53 is a function block storing parameters of a neural network (hereinafter referred to as "NN parameters") for estimating the processing amount, such as the screw tightening depth, based on the time series data of the motor rotation speed and the motor current. The NN parameters include weights and biases. The NN parameters are generated in advance by machine learning. The method of machine learning will be described later.

[0061] The motor output setting unit 54 detects the conduction of the trigger switch 15 and sends the result to the output stability determination unit 55. In addition, the motor output setting unit 54 sends an output setting signal corresponding to the amount of the trigger switch 15 pulled to the motor control unit 61.

[0062] When a predetermined time has passed since the trigger switch 15 was turned on, the output stability determination unit 55 determines that the output of the motor 20 is stable, and changes the neural network calculation valid signal (hereinafter referred to as "NN calculation valid signal") from low level (invalid) to high level (valid).

[0063] When the NN calculation valid signal is at a high level, the NN calculation unit 56 calculates a machining amount estimation value based on the time series data of the motor rotation speed and the motor current measurement values ​​stored in the data storage unit 52 and the NN parameters stored in the learned model 53 .

[0064] The threshold setting unit 57 receives the threshold setting input value from the threshold setting device 48 and outputs the threshold. The comparator 58 compares the machining amount estimation value with the threshold, and outputs a low level signal if the machining amount estimation value is below the threshold, and outputs a high level signal if the machining amount estimation value exceeds the threshold.

[0065] The control mode setting unit 59 detects the operation of the control mode switching switch 47 and outputs a machining amount control mode valid / invalid signal. The machining amount control mode valid / invalid signal is high level when the machining amount control mode is valid, and is low level when it is invalid. The display unit 46 displays the validity or invalidity of the machining amount control mode.

[0066] The AND gate 60 outputs a signal of the logical product of the machining amount control mode valid / invalid signal and the output signal of the comparator 58. In other words, the AND gate 60 reports the output signal of the comparator 58 to the motor control unit 61 when the machining amount control mode valid / invalid signal is at a high level (when the machining amount control mode is valid).

[0067] The output signal of the AND gate 60 is at a high level, which means that the machining amount control mode is effective and the machining amount estimated value exceeds the threshold value, and the stop / low speed control request signal is output to the motor control unit 61. The output signal of the AND gate 60 is at a low level, which means that the machining amount control mode is invalid and / or the machining amount estimated value is below the threshold value, and the stop / low speed control request signal is not output to the motor control unit 61.

[0068] The motor control unit 61 outputs a motor control signal corresponding to the output setting signal from the motor output setting unit 54 to the drive signal output circuit 49 ( Figure 3 When the motor control unit 61 receives the stop / low speed control request signal, i.e., when the stop / low speed control request signal is at a high level, the motor control unit 61 outputs the motor control signal for stopping / low speed controlling the motor 20 to the drive signal output circuit 49 ( Figure 3 ).

[0069] The stop / low speed control is a control to stop the motor 20, or a control to decelerate the motor 20 and rotate it at a low speed. Regarding the control to stop the motor 20, the motor 20 may be braked, or the motor 20 may be naturally decelerated without applying the brake. Thus, the processing amount control mode is a mode in which the motor 20 is stopped / low speed controlled when the processing amount estimation value exceeds the threshold value. The processing amount control mode corresponds to the screw tightening depth control mode and the processing amount estimation mode.

[0070] Figure 5 is a control flow chart of the control unit 40 in the stopped state. When the trigger switch 15 is turned on (S1 is (YES)), the control unit 40 enters Figure 6 The flowchart in the operation state shown in FIG. 1 ( S3 ) When the trigger switch 15 is turned off (NO in S1 ), the control unit 40 stops the motor 20 ( S5 ).

[0071] When the control mode switching switch 47 is turned on (Yes in S7), the control unit 40 sets the machining amount control mode valid / invalid signal to a high level (valid) (S9). When the control mode switching switch 47 is turned off (No in S7), the control unit 40 sets the machining amount control mode valid / invalid signal to a low level (invalid) (S11).

[0072] The control unit 40 checks the threshold setting input value from the threshold setting device 48 (S13). If the threshold setting input value does not match the current threshold value (Yes in S15), the control unit 40 updates the threshold value (substitutes the threshold setting input value into the threshold value) (S17), and returns to S1. If the threshold setting input value matches the current threshold value (No in S15), the control unit 40 returns to S1.

[0073] Figure 6 4 is a control flow chart of the control unit 40 in the operating state. The control unit 40 obtains the motor current and the motor speed as the tool state data (S21). When the machining amount control mode is valid (Yes in S23), and when the NN calculation valid signal is at a high level (Yes in S25), the control unit 40 performs a neural network operation (hereinafter referred to as "NN operation") and derives a machining amount estimation value based on the learning completed model 53 (S27).

[0074] When the estimated processing amount exceeds the threshold value (Yes in S29), the control unit 40 stops / low-speed controls the motor 20 (S31). When the estimated processing amount does not exceed the threshold value (No in S29), the control unit 40 performs normal control on the motor 20, that is, the rotation speed control corresponding to the amount of trigger switch 15 being pulled (S33).

[0075] In the case of a screw-tightening machine such as the electric tool 1, the processing amount is determined by the screw-tightening depth (the length of the screw tip penetrating into the workpiece), or Figure 7 The screw head lifting amount shown in (A) (the distance from the surface of the target material to the screw head and the distance until the top of the screw head becomes flush with the surface of the target material) is represented. In the case where the processing amount is the screw head lifting amount, the smaller the processing amount, the more processing is carried out, so the direction of the inequality sign in the judgment of S29 becomes opposite. That is, the control unit 40 stops / low-speed controls the motor 20 when the processing amount estimate value (estimated value of the screw head lifting amount) is less than the threshold value, and normally controls the motor 20 when the processing amount estimate value (estimated value of the screw head lifting amount) is greater than the threshold value. In addition, the current estimated value of the screw head lifting amount can be subtracted from the estimated value of the screw head lifting amount initially derived to set it as the estimated value of the screw tightening depth.

[0076] In the case of a screw such as a wood screw, since the screw is accompanied by drilling processing on the target material, the screw tightening depth or the screw head floating amount is an example of the amount of irreversible processing on the target material. On the other hand, for example, the tightening of a bolt and a nut is not accompanied by drilling processing and is therefore a reversible processing.

[0077] When the machining amount control mode is not effective (No in S23) or when the NN calculation effective signal is at a low level (No in S25), the control unit 40 performs normal control (S33) on the motor 20. When the NN calculation effective signal is at a low level, the output of the motor 20 is unstable before a predetermined time has passed since the trigger switch 15 was turned on, and there is a risk of misjudgment due to the starting current, etc., so the NN calculation (S27) is not advanced.

[0078] Figure 7 (A) to (F) are schematic cross-sectional views showing how a screw-tightening operation on a target material is performed. Figure 7 (A) is a state at the start of screw tightening, showing a state in which the drill bit 37 of the electric tool 1 is engaged with the screw 63 and the screw 63 is erected on the surface of the gypsum board 64 . Figure 7 (B) to (E) show the state in which the screws are being tightened. Figure 7 (B) shows a state before the tip of the screw 63 reaches the base 65 . Figure 7 (C) shows a state where the tip of the screw 63 reaches the base 65 . Figure 7 (D) shows a state where the tip of the screw 63 advances in the base 65 . Figure 7 (E) is a state in which the screw 63 is already in place, and shows a state in which the lower end of the head portion (lower end of the tapered portion) of the screw 63 comes into contact with the surface of the gypsum board 64 and begins to penetrate. Figure 7(F) shows a state where the head of the screw 63 is flush with the surface of the gypsum board 64, that is, a state where the screw head floating amount is zero.

[0079] Figure 7 (G) means Figure 7 (A) to (F) are graphs showing the time changes of motor current, motor rotation speed, and screw head lift amount during screw tightening work. A to F in the graph represent Figure 7 The time portion or time range corresponding to each state (A) to (F). Figure 7 The measured values ​​of the motor current and the motor speed as shown in the graph of (G) and the time series data of the screw head lifting amount obtained by the external distance measuring sensor are used to generate Figure 4 The learning model 53 shown is used in the machine learning of the NN parameters. In the design stage of the electric tool 1, various types of screws are tightened into various types of target materials, and the control unit 40 performs the operation based on Figure 7 By performing machine learning on the time series data as shown in the graph of (G), NN parameters that can cope with various types of screws, various types of target materials, and the presence or absence of impact are generated.

[0080] Figure 8 2 is a graph showing the correlation between the current and the number of revolutions of the motor 20 of the electric tool 1 and the amount of screw head lift. Figure 8 As shown, the motor speed is positively correlated with the screw head floating amount, while the motor current is negatively correlated with the screw head floating amount. That is, the following correlation can be confirmed: when the motor current is small and the motor speed is large, the screw head floating amount is large, and when the motor current is large and the motor speed is small, the screw head floating amount is small.

[0081] Fig. 9 : is a conceptual diagram showing the structure of a neural network for estimating the screw head lift amount of the electric tool 1. Figure 8 As shown in FIG. 1 , there is a correlation between the screw head lift amount and the motor current and motor speed. Using the correlation, as Fig. 9 As shown, the screw head lift amount can be estimated by using a neural network that takes the motor current and motor rotation speed time series data of a specified number of samples as input and the screw head lift amount as output. Fig. 9 The learned model 53 in which the neural network having the structure shown has been machine-learned performs an estimation calculation of the actual screw head lifting amount.

[0082] like Fig.10As shown, in estimating the screw head lift at time t, the time series data of the motor current and the motor rotation number from time tn to time t are used as input. The length of time from time tn to time t and the amount of time series data can be arbitrarily set according to the specifications of the electric tool 1.

[0083] Fig.11 is Fig.10 The graph is a graph in which the estimated value of the screw head lift is added to the graph. The estimated value of the screw head lift is a value obtained by calculating the time series data of the motor current and the motor speed that is actually input to the learned neural network. The estimated value of the screw head lift roughly follows the measured value of the screw head lift. When the estimated value of the screw head lift is lower than the set threshold value ("motor stop threshold value" in the figure) (when the estimated value of the screw tightening depth exceeds the set threshold value), the motor 20 is stopped or driven at a low speed, thereby automatically stopping when in position, automatically stopping when the screw head lift is zero, or stopping at a specified screw head lift (specified screw tightening depth), etc.

[0084] This embodiment exerts the following effects.

[0085] (1) The control unit 40 can estimate the screw head floating amount based on the measured motor current and motor rotation speed at any time point before and after the rotary striking mechanism 30 starts striking in screw tightening operations under various operating conditions. Therefore, by presetting a threshold value corresponding to the in-position, even if the screw is in-position before the rotary striking mechanism 30 starts striking, it is possible to determine whether the screw is in-position and stop or decelerate the motor 20. The processing amount control mode in the case of the threshold value corresponding to the in-position corresponds to the in-position determination mode.

[0086] (2) The control unit 40 determines whether the screw is in place based on the measured motor current and motor rotation speed. Therefore, compared with the case where the position determination is performed only based on the motor current, over-tightening or under-tightening can be suppressed, and the workability is improved.

[0087] (3) The control unit 40 is configured to have a learning model (learned model 53) that estimates the screw tightening depth (screw head lifting amount) based on the measured motor current and motor rotation speed, and stops or decelerates the motor 20 based on the estimated screw tightening depth and the set value (threshold value). Therefore, it is possible to achieve high-precision estimation of the screw tightening depth (screw head lifting amount) using a neural network.

[0088] (4) The control unit 40 can estimate the screw tightening depth (screw head floating amount) before the screw is in place. Correspondingly, the threshold setting device 48 is configured to be able to set multiple screw tightening depths including the first screw tightening depth (first screw head floating amount) before the screw is in place on the target material, and the second screw tightening depth different from the first screw tightening depth as thresholds (set values). Therefore, the motor 20 can be stopped or decelerated at the stage before the screw is in place, and the situation where the screw tightening depth needs to be manually adjusted before and after the screw is in place can be appropriately dealt with, and the workability is good. As the second screw tightening depth, the screw settlement amount (negative screw head floating amount) when the screw head is in place on the target material and further sinks into the target material can also be set, which can appropriately deal with various work requirements.

[0089] (Implementation Method 2) Figure 12 to Figure 17 The present invention relates to an electric tool according to a second embodiment of the present invention. The electric tool is the same as the first embodiment except for a method of estimating (calculating) a machining amount.

[0090] Fig.12 FIG. 1 is a functional block diagram of a control unit 140 of an electric tool according to a second embodiment of the present invention. Figure 4 The learning model 53 and the NN operation unit 56 of the control unit 40 are replaced with the machining amount calculation program 62. Figure 4 The NN calculates the effective signal in Fig.12 The signal is replaced by the machining amount calculation valid signal, but its function is the same as the signal. Fig.14 And will be described later.

[0091] Fig.13 is a control flow chart of the control unit 140 in the running state. Figure 5 The control unit 140 obtains the motor current and motor speed as tool status data (S41). When the machining amount control mode is valid (Yes in S43) and the machining amount calculation valid signal is at a high level (Yes in S45), the control unit 140 executes Fig.14 The processing amount calculation flow chart shown in FIG. 1 is used to derive a processing amount calculation value ( S47 ).

[0092] When the machining amount calculation value exceeds the threshold value (Yes in S49), the control unit 140 stops / low-speed controls the motor 20 (S51). When the machining amount calculation value does not exceed the threshold value (No in S49), the control unit 140 performs normal control on the motor 20, that is, the rotation speed control corresponding to the amount of trigger switch 15 being pulled (S53). When the machining amount control mode is not effective (No in S43) or when the machining amount calculation effective signal is at a low level (No in S45), the control unit 140 performs normal control on the motor 20 (S53).

[0093] Fig.14 This is a flowchart of the processing amount calculation of the control unit 140. When the time elapsed from the processing amount calculation valid signal becoming a high level (from proceeding to S45's Yes) does not exceed a predetermined time (S61's No), the control unit 140 integrates the motor current × motor rotation number (S63). The integrated value is used for calculating the reference output in S65 described later.

[0094] When the time elapsed since the machining amount calculation valid signal becomes high level (from the progress to S45's Yes) exceeds the prescribed time (S61's Yes), the control unit 140 calculates the value obtained by dividing the integral value calculated in S63 by the prescribed time as a reference output (S65). The reference output is used as a judgment reference value for changing the control according to the combination of the target material and the screw, that is, for selecting the table used in S71 or S73 described later.

[0095] The control unit 140 performs a high-speed Fourier transform (FFT) process on the measurement data of the motor current. In the spectrum obtained by FFT, if the amplitude value of the specified frequency exceeds the specified value (Yes in S69), the control unit 140 determines that the rotating striking mechanism 30 has struck and proceeds to S71. If not (No in S69), the control unit 140 determines that no striking has been performed and proceeds to S73. The specified frequency at this time is set to the hammer 32 ( Figure 2 ) divided by the rotation frequency of the hammer 32 and the anvil 33 ( Figure 2 ) is a value obtained by calculating the number of meshing teeth.

[0096] After the control unit 140 makes a striking judgment (S69), it derives a calculated value of the screw tightening depth (screw head floating amount) based on a pre-prepared table and based on the reference output value, current value, and number of revolutions. Regarding the table at this time, different tables are used when striking and when not striking. That is, when the control unit 140 determines that the rotary striking mechanism 30 has struck (Yes in S69), it derives a calculated value (estimated value) of the screw tightening depth (screw head floating amount) based on the table used before striking and based on the reference output, motor current, and motor number of revolutions (S71). When the control unit 140 determines that the rotary striking mechanism 30 has struck (No in S69), it derives a calculated value (estimated value) of the screw tightening depth (screw head floating amount) based on the table used after striking and based on the reference output, motor current, and motor number of revolutions (S73).

[0097] Fig.15 This is a conceptual diagram showing an example of a table used for estimating the amount of machining before the start of striking. Fig.16 1 and 2 are conceptual diagrams showing an example of a table used for estimating the machining amount after the start of the hammering. As shown in these figures, the table is constructed as a three-dimensional table that determines the estimated value of the screw head lifting amount based on the reference output, the motor current, and the motor rotation speed.

[0098] Fig.17 This is a graph showing the relationship between the product of the motor current and the motor rotation speed and the screw head lift for two types of screws. The two screws are of different lengths, with screw 2 being longer than screw 1. Fig.17 In the graph, the relationship between the product of the measured values ​​of the motor current and the motor speed when the screw tightening operation is performed 20 times on each of the two types of screws and the measured value of the screw head floating amount is plotted. Fig.18 Yes means Fig.17 A graph of the average curve of the data for the two screws.

[0099] In this embodiment, if Fig.17 As shown in FIG. 1 , a table used in estimating the machining amount is generated and stored in advance based on the previously acquired actual measurement data of the motor current, motor rotation speed, and screw head lifting amount. Fig.18 As shown in FIG. 1 , the table is generated in the form of an average curve of the data of the screw head floating amount relative to the product of the motor current and the motor rotation number. According to this embodiment, when the types of screws or target materials are different, the output ( Fig.14 In the case where the reference output calculated in S65 is slightly different, a table that can cope with various types of screws and various types of target materials is generated in advance. This embodiment also exerts the same or corresponding effects as the first embodiment.

[0100] The present invention has been described above by taking the embodiments as examples, but it should be understood by those skilled in the art that various modifications can be made to the structural elements or processing procedures of the embodiments within the scope of the claims.

[0101] The amount of irreversible processing of the present invention is not limited to the screw tightening depth or the screw head floating amount, and may be, for example, the drilling depth. The power tool of the present invention is not limited to an impact tool, and may be other types of tools such as a drill driver or an oil pulse tool that can perform screw tightening or drilling. Furthermore, the present invention can be applied to all power tools in which the state quantity such as the motor current or the motor speed or its time series data has a correlation with the processing amount.

[0102] The time, motor current, motor rotation speed, screw head lifting amount, reference output, etc. exemplified as specific numerical values ​​in the embodiments or drawings do not limit the scope of the invention at all, and vary depending on the specifications of the product.

[0103] Explanation of symbols

[0104] 1: Power tools

[0105] 10: Casing

[0106] 11: Motor housing

[0107] 12: Handle part

[0108] 13: Battery assembly equipment

[0109] 14: Tail hood

[0110] 15: Trigger switch

[0111] 16: Forward and reverse switch

[0112] 17: Battery Pack

[0113] 18: Hammer Shell

[0114] 19: Operation panel

[0115] 20: Motor

[0116] 21: Motor shaft

[0117] 22: Rotor

[0118] 23: Stator core

[0119] 24: Stator coil

[0120] 25: Front insulator

[0121] 26: Rear insulator

[0122] 28: Speed ​​reduction mechanism

[0123] 29: Spindle

[0124] 30: Rotating striking mechanism

[0125] 31: Spring

[0126] 32: Hammer

[0127] 33: Anvil

[0128] 34: Fan

[0129] 35: First control substrate

[0130] 36: Second control substrate

[0131] 37: Drill

[0132] 38: Inverter circuit

[0133] 39: Resistance

[0134] 40: Control Department

[0135] 41: Current detection circuit

[0136] 42: Battery voltage detection circuit

[0137] 43: Control power supply circuit

[0138] 44: Control power supply voltage detection circuit

[0139] 45: Rotor position detection circuit

[0140] 46: Display unit

[0141] 47: Control mode switch

[0142] 48: Threshold value setting device (setting unit)

[0143] 49: Drive signal output circuit

[0144] 50: Magnetic sensor

[0145] 51: Rotation calculation unit

[0146] 52: Data storage department

[0147] 53: Learning the model

[0148] 54: Motor output setting unit

[0149] 55: Output stability determination unit

[0150] 56: NN operation unit

[0151] 57: Threshold setting unit

[0152] 58: Comparator

[0153] 59: Control mode setting unit

[0154] 60: AND gate

[0155] 61: Motor control unit

[0156] 62: Processing volume calculation program

[0157] 63: Screw

[0158] 64: Gypsum board

[0159] 65: Base

Claims

1. An impact tool comprising: motor; an impact mechanism driven by the motor; a current measuring unit for measuring the current of the motor; a rotation speed measuring unit to detect the rotation speed of the motor; and a control unit, controlling the motor, The impact tool is characterized in that: The control unit has a position determination mode, which is configured to determine whether the screw is in place based on the measured current of the motor and the rotation speed of the motor at any time point before and after the impact mechanism starts to strike during screw tightening operations under multiple different operating conditions, and stop or slow down the motor after it is determined that the screw is in place.

2. The impact tool according to claim 1, characterized in that: The control unit is configured so that in the in-position determination mode, In the screw tightening operation under the first operation condition, when the current of the motor and the rotation speed of the motor reach the first value and the second value respectively before the striking starts, it is determined that the screw is in place, and In the screw tightening operation under a second operation condition different from the first operation condition, when the current of the motor and the rotation speed of the motor reach third and fourth values ​​respectively different from the first and second values ​​after the start of striking, it is determined that the screw is seated.

3. The impact tool according to claim 2, characterized in that: The control unit is configured to include a learning model for estimating a screw tightening depth based on the measured current of the motor and the rotation speed of the motor, and to stop or decelerate the motor based on the estimated screw tightening depth and a set value.

4. An electric tool comprising: motor; as well as a control unit, controlling the motor, The electric tool is characterized in that: The control unit has a screw tightening depth control mode, wherein the screw tightening depth control mode is configured to estimate the screw tightening depth relative to the target material based on the measured state quantity of the electric tool, and control the motor based on the estimated screw tightening depth and a setting value set by the setting unit. The setting unit is configured to be able to set a plurality of screw tightening depths including a first screw tightening depth before the screw is seated on the target material and a second screw tightening depth different from the first screw tightening depth as setting values.

5. The electric tool according to claim 4, characterized in that: The screw tightening depth is the distance between the screw head and the target material, that is, the screw floating amount, or the screw sinking amount when the screw head is located on the target material and further sinks into the target material.

6. The electric tool according to claim 4, characterized in that: The second screw tightening depth is the screw tightening depth after the screw is positioned on the target material.

7. The electric tool according to any one of claims 4 to 6, characterized in that: The control unit includes a learning model for estimating a screw tightening depth relative to a workpiece based on the measured state quantity of the electric tool, and stops or decelerates the motor based on the estimated screw tightening depth and a setting value set by the setting unit.

8. An electric tool comprising: motor; a current measuring unit for measuring the current of the motor; A rotation speed measuring unit, for detecting the rotation speed of the motor; as well as a control unit, controlling the motor, The electric tool is characterized in that: The control unit has a processing amount estimation mode configured to estimate the amount of irreversible processing on the target material, namely, the processing amount, based on the measured current of the motor and the rotation speed of the motor, and control the motor based on the estimated processing amount.

9. The electric tool according to claim 8, characterized in that: The processing amount is the screw tightening depth or the drilling depth.

10. The electric tool according to claim 8 or 9, characterized in that: The control unit includes a learning model configured to estimate a machining amount for a workpiece based on the measured current of the motor and the rotation speed of the motor, and controls the motor based on the estimated machining amount and a setting value set by the setting unit.

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