WO2020008666A1

WO2020008666A1 - Power tool, method for controlling same, and control program

Info

Publication number: WO2020008666A1
Application number: PCT/JP2019/001789
Authority: WO
Inventors: 川本　竜二; 啓之伊夫伎; 充典杉浦
Original assignee: オムロン株式会社
Priority date: 2018-07-02
Filing date: 2019-01-22
Publication date: 2020-01-09
Also published as: JP2020001147A

Abstract

A power tool (10) comprises a motor (16), a trigger switch (12), a switching circuit (gate circuit (13) and FET array (14)), and a control unit (20). The trigger switch (12) sets the speed of the motor (16) in accordance with a manipulation amount. The switching circuit has a plurality of switching elements (14a) and supplies electric power to the motor (16). The control unit (20) controls the switching circuit so that the motor is rotationally driven on the basis of the speed set by the trigger switch (12), and has a trial run mode for estimating an operation mode. The operation mode is estimated on the basis of a characteristic value of the motor (16) as acquired in the trial run mode.

Description

Electric power tool, control method therefor, and control program

The present invention relates to a power tool, a control method thereof, and a control program.

Electric tools usually perform various operations such as screw tightening and drilling using the motor control parameters set at the time of factory shipment as they are. For this reason, in drilling and text screw tightening, various processing members (hard materials such as metal and keyaki, soft materials such as gypsum and cedar, heterogeneous materials such as natural solid wood, gypsum board and laminated wood, etc.) However, there was a problem that only moderate workability could be obtained with respect to homogeneous materials.

For example, in Patent Document 1, a learning operation is performed in a predetermined sample mode to learn a use condition of a motor and store it as control information (for example, a tightening time by a motor, a current limit value, a rotation speed, and the like). A power tool that can realize an optimal drive mode for each user is disclosed.

Japanese Patent Application Laid-Open No. 2015-091626

However, the above-described conventional power tool has the following problems.
That is, in the power tool disclosed in the above-mentioned publication, a user can select a desired operation mode (for example, four types of “wood mode”, “bolt mode”, “text thick plate mode”, and “text thin plate mode”). Is selected, the user has to operate a switch for selecting an optimum mode for each operation. Further, since the user needs to select one work mode determined to be optimum from the work modes prepared in advance, there is a problem that the number of selectable modes is limited to several kinds prepared in advance. .

An object of the present invention is to provide a power tool capable of automatically selecting an optimum mode for each work and performing the work without the user himself selecting a mode suitable for various works, and a control method therefor. To provide a control program.

The power tool according to the first invention includes a DC motor, a speed setting unit, a switching circuit, and a control unit. The speed setting unit sets the rotation speed of the DC motor according to the operation amount. The switching circuit has a plurality of switching elements and supplies power to the DC motor. The control unit controls the switching circuit so as to rotate the DC motor based on the rotation speed set in the speed setting unit, and has a trial mode for estimating a work mode. The work mode is estimated based on the obtained DC motor characteristic values.

Here, for example, when starting various operations using a power tool such as text screw tightening, drilling, bolt tightening, and bolt loosening, in a predetermined trial mode, the power tool is applied to a work material to be processed in the predetermined trial mode. The work used is performed, and based on the acquired characteristic values of the DC motor, a work mode optimal for the work is estimated.

Here, as the work mode to be estimated, for example, a text mode in which a work using a text screw is performed, a bolt tightening mode in which a bolt is tightened, a bolt loosening mode in which a bolt is loosened, a strong mode in which a long screw is tightened, a cosmetic material, or the like A medium mode for tightening screws, a weak mode for tightening screws to a gypsum board or the like, an iron drill mode using an iron drill, a wood drill mode using a wood drill, and the like are included.

Further, the characteristic value of the DC motor obtained by performing the work on the processing material to be processed in the state where the trial mode is set includes a current value flowing through the DC motor, a rotation pulse, and the like. It is.

Thus, before performing the work, it is possible to estimate the optimum work mode for the work by using the characteristic values acquired by performing the work in the trial mode.
Therefore, the user can automatically select an optimal mode for each operation and perform the operation without selecting the mode suitable for various operations.

A power tool according to a second invention is the power tool according to the first invention, wherein the control unit controls the DC motor according to the operation amount of the speed setting unit based on the estimated operation mode.
Here, when performing the work after the estimation of the work mode, the DC motor is controlled in accordance with the operation amount of the speed setting unit while the estimated work mode is automatically selected.
Thus, the work can be started in a state where the optimum work mode is automatically selected.
Therefore, the work can be performed under the control condition optimized for each work, so that the work efficiency can be improved.

A power tool according to a third invention is the power tool according to the first or second invention, wherein the characteristic value includes at least one of a current value of the DC motor and a rotation pulse acquired in the trial mode. .
Here, at least one of a current value flowing through the DC motor and a rotation pulse is used as the characteristic value of the DC motor used for estimating the work mode.
Thus, it is possible to estimate an optimal work mode using the current value and / or the rotation pulse of the DC motor acquired in the trial mode.

The power tool according to a fourth aspect is the power tool according to the third aspect, wherein the control unit is configured to control the first current value and the load state from a first current value after a predetermined time when the DC motor enters the load state. second current value before the predetermined time from the time of change to the no-load condition, when the total time a loaded conditions was T _all, from the third time point when loaded conditions of T _{all 1/3} elapse The work mode is estimated using at least one characteristic value of the ratio of the current value and the fourth current value at the time when T _all 2/3 has elapsed, and the total number of rotations in the loaded state.

Here, the first current value, the second current value, the ratio of the third and fourth current values are obtained from the current value of the DC motor described above, and the total number of rotations in a loaded state is obtained from the above-described rotation pulse, The work mode is estimated using these four feature amounts.

Here, these four feature amounts are set as feature amounts in which features are likely to appear in each work mode.
Thus, by estimating the work mode by combining one or more of these four feature amounts, it is possible to improve the accuracy of the work mode estimation.

The power tool according to a fifth aspect is the power tool according to any one of the first to fourth aspects, further comprising a trial switch operated by a user when the trial mode is performed.

Here, when the trial mode is performed before the work is started, for example, the trial switch provided on the outer surface of the power tool is operated by the user.
Accordingly, when the trial mode is performed to estimate the optimal work mode, the trial mode is easily implemented by providing the trial switch at a position where the user can easily operate. it can.

A power tool according to a sixth aspect is the power tool according to any one of the first to fifth aspects, wherein the work mode estimated by the control unit includes a text mode, a bolt tightening mode, and a bolt loosening mode. At least one of a mode, a strong mode, a medium mode, a weak mode, an ironwork mode, and a woodwork mode is included.

Here, the text mode, the bolt tightening mode, the bolt loosening mode, the strong mode, the medium mode, the weak mode, the ironwork mode, and the woodwork mode are given as examples of the estimated work mode.
Thus, by detecting characteristic characteristic values in various operation modes, it is possible to estimate an optimal operation mode for various operations.

A power tool according to a seventh aspect is the power tool according to any one of the first to sixth aspects, further comprising a storage unit that stores the work mode estimated by the control unit.
Here, the estimated work mode is stored in the storage unit.
Thus, by starting the work using the work mode estimated by the control unit and stored in the storage unit, the work can be performed in a state automatically set to the work mode optimal for the work. .

An electric power tool according to an eighth aspect is the electric power tool according to any one of the first to seventh aspects, wherein the control unit, when the estimated operation mode is a predetermined operation mode, A change in the current value of the DC motor is detected, and when the rate of change exceeds a predetermined threshold, the rotation of the DC motor is stopped.

Here, in the case where the estimated work mode is a specific work mode, stop control is performed to stop the rotation of the DC motor when the change in the current value of the DC motor exceeds a predetermined threshold.

Here, the specific work mode includes, for example, a text mode in which text screws are tightened, a bolt loosening mode in which bolts are loosened, and the like.
Thus, for example, in the text mode, when the text screw reaches a desired tightening state and the current value shows a change rate exceeding the threshold value, the rotation of the DC motor is prevented in order to prevent the head of the text screw from jumping or breaking. Can be stopped.

Further, for example, in the bolt loosening mode, when the rotational resistance of the bolt becomes light and the current value shows a change rate exceeding a predetermined threshold value, in order to prevent the detached bolt from dropping, The rotation of the motor can be stopped.

結果 As a result, by detecting from the change rate of the current value that there is no need for further rotation in a specific work mode, it is possible to perform optimal motor control in each work mode.

A power tool according to a ninth aspect is the power tool according to any one of the first to eighth aspects, wherein the control unit sets a work mode based on a characteristic value acquired in the trial mode. Estimate using fuzzy inference.

Here, the above-described estimation of the optimal work mode is performed using fuzzy inference.
Thereby, based on the characteristic values acquired in the above-described trial mode, the optimal work mode is estimated using fuzzy inference, so that the optimal work mode is automatically selected for the work. Can be implemented.

A control method for a power tool according to a tenth aspect is the control method for the power tool according to any one of the first to ninth aspects, wherein the DC motor is controlled in a trial mode under a preset control condition. , Rotating in a trial mode, acquiring a characteristic value of the DC motor in the trial mode, and estimating a work mode based on the characteristic value acquired in the trial mode.

Here, as the estimated work mode, for example, a text mode in which work using a text screw is performed, a bolt tightening mode in which bolts are tightened, a bolt loosening mode in which bolts are loosened, a strong mode in which long screws are tightened, a cosmetic material, or the like A medium mode for tightening screws, a weak mode for tightening screws to a gypsum board or the like, an iron drill mode using an iron drill, a wood drill mode using a wood drill, and the like are included.

An electric tool control method according to an eleventh aspect of the present invention is the electric tool control method according to the tenth aspect, wherein the direct current motor is controlled in accordance with the operation amount of the speed setting unit based on the estimated working mode. Further comprising the step of:

Here, when performing the work after the estimation of the work mode, the DC motor is controlled in accordance with the operation amount of the speed setting unit while the estimated work mode is automatically selected.
Thus, the work can be started in a state where the optimum work mode is automatically selected.
Therefore, the work can be performed under the control condition optimized for each work, so that the work efficiency can be improved.

A control method for a power tool according to a twelfth invention is the control method for a power tool according to the tenth or eleventh invention, wherein the characteristic value includes a current value and a rotation pulse of the DC motor acquired in the trial mode. At least one is included.
Here, at least one of a current value flowing through the DC motor and a rotation pulse is used as the characteristic value of the DC motor used for estimating the work mode.
Thus, it is possible to estimate an optimal work mode using the current value and / or the rotation pulse of the DC motor acquired in the trial mode.

A control method for a power tool according to a thirteenth invention is the control method for a power tool according to the twelfth invention, wherein the step of estimating the work mode includes a step after a predetermined time when the DC motor enters a loaded state. The first current value, the second current value a predetermined time before the time when the state changes from the loaded state to the no-load state, and the total time when the loaded state is set to _Tall , from the time when the loaded state is reached. T _{all 1/3} ratios of the fourth current value of the third current value and T _{all 2/3} elapse elapsed time, using at least one characteristic quantity of the total number of revolutions in loaded conditions, estimating the working mode I do.

Here, the first current value, the second current value, the ratio of the third and fourth current values are obtained from the current value of the DC motor described above, and the total number of rotations in a loaded state is obtained from the above-described rotation pulse. The work mode is estimated using the four feature amounts.

A control method for a power tool according to a fourteenth invention is the control method for a power tool according to any one of the tenth to thirteenth inventions, wherein the work mode estimated includes a text mode and a bolt fastening mode. , Bolt loosening mode, strong mode, medium mode, weak mode, ironwork mode, and woodwork mode.

A power tool control method according to a fifteenth invention is the power tool control method according to any one of the tenth to fourteenth inventions, wherein the estimated work mode is a predetermined work mode. Further comprises a step of detecting a change in the current value of the DC motor and stopping the rotation of the DC motor when a rate of the change exceeds a predetermined threshold.

A control method for a power tool according to a sixteenth invention is the control method for a power tool according to any one of the tenth to fifteenth inventions, wherein fuzzy inference is used for estimating a work mode.
Here, the above-described estimation of the optimal work mode is performed using fuzzy inference.

Thereby, based on the characteristic values acquired in the above-described trial mode, the optimal work mode is estimated using fuzzy inference, so that the optimal work mode is automatically selected for the work. Can be implemented.

A control program for a power tool according to a seventeenth invention is a control program for a power tool according to any one of the first to ninth inventions, wherein the DC motor is controlled in a trial mode in a preset control condition. A power tool control method, comprising: a step of rotating and driving; a step of acquiring a characteristic value related to a DC motor in a trial mode; and a step of estimating a work mode based on the characteristic value acquired in the trial mode. On a computer.

(The invention's effect)
ADVANTAGE OF THE INVENTION According to the electric power tool which concerns on this invention, a user can implement work in an optimal mode, without selecting a desired mode by himself.

FIG. 1 is a control block diagram illustrating a configuration of a power tool according to an embodiment of the present invention. 3A is a table showing a relationship between an operation amount of a trigger switch and a target rotation speed stored in a storage unit of the power tool in FIG. 1; (B) is a graph of the table. 2 is a flowchart illustrating a flow of a control method of the power tool in FIG. 1. 4 is a flowchart showing a flow of initial setting in FIG. 3. 3A and 3B are tables and graphs showing a relationship between an operation amount of a trigger switch of the power tool of FIG. 1 and an output duty in a default state. 4 is a flowchart showing the flow of processing in the trial mode in FIG. FIG. 4 is a flowchart showing the flow of processing for estimating a work mode in FIG. 3; FIG. (A)-(d) is a graph showing a membership function indicating a relationship between each parameter using a current value and a rotation pulse and each operation mode. 9 is a table showing a relationship between each parameter using a current value and a rotation pulse and each operation mode as a numerical value of a membership function. (A)-(d) is a graph showing a method of calculating a fitness using a membership function indicating a relationship between each parameter using a current value and a rotation pulse and each work mode. 4 is a graph showing a relationship between an operation amount of a trigger switch of the power tool and an output duty in each operation mode. (A) is a figure showing a text screw mode. (B) is a figure which shows step-by-step work in the text screw mode. (C) is a graph showing the relationship between the motor current and the motor speed in the text screw mode. (D) is a graph showing ON / OFF of the trigger switch in the text screw mode. (E) is a graph showing the normal rotation / reversal of the direction switch in the text screw mode. (A) is a figure which shows a mode of a bolting operation | work. (B) is a graph which shows the relationship between motor current and motor speed in bolt work. (C) is a graph showing ON / OFF of a trigger switch in a bolt tightening operation. (D) is a graph which shows the normal rotation / reversal of the direction switch in bolting work. (A) is a figure showing a situation of bolt loosening work. (B) is a graph showing the relationship between the motor current and the motor speed in the bolt loosening work. (C) is a graph which shows ON / OFF of a trigger switch in bolt loosening work. (D) is a graph showing the forward / reverse rotation of the direction switch in the bolt loosening operation. (A) is a figure which shows the mode of a tapping screw fastening (there is a prepared hole) operation | work. (B) is a graph showing the relationship between the motor current and the motor speed in the tapping screw fastening operation. (C) is a graph showing ON / OFF of a trigger switch in a tapping screw tightening operation. (D) is a graph which shows the normal rotation / reversal of the direction switch in the tapping screw fastening operation. (A) is a figure which shows the mode of operation | work using the drill for ironsmiths. (B) is a graph showing a relationship between a motor current and a motor speed in an operation using an iron drill. (C) is a graph which shows ON / OFF of the trigger switch in the work using the drill for ironsmiths. (D) is a graph showing the forward / reverse rotation of the direction switch in the work using the drill for ironsmith. (A) is a figure showing a situation of work using a drill for woodworking. (B) is a graph showing a relationship between a motor current and a motor speed in an operation using a woodworking drill. (C) is a graph showing ON / OFF of a trigger switch in work using a woodworking drill. (D) is a graph showing the forward / reverse rotation of the direction switch in the work using the woodworking drill. 4 is a flowchart showing the flow of processing in a trial result execution mode in FIG. 3.

A power tool according to an embodiment of the present invention will be described below with reference to FIGS.
The power tool 10 according to the present embodiment rotates a tip tool such as a driver or a drill mounted on the tip portion thereof by a brushless motor (motor 16) supplied with power from the battery 11. As shown in FIG. 1, the power tool 10 includes a battery (power supply unit) 11, a trigger switch (speed setting unit) 12, a switching circuit (gate circuit 13, an FET (Field Effect Transistor) array 14), a current detection resistor. 15, a motor 16, a magnetic pole position detection circuit 17, a trial switch 18, and a control unit 20.

The battery (power supply unit) 11 is, for example, a replaceable rechargeable battery that is mounted on a grip portion of the power tool 10, and is used as a power source of the power tool 10. Further, as shown in FIG. 1, the battery 11 is connected to the FET array 14 and the control unit 20, and supplies power to each.

Although not shown, a constant-voltage power supply for generating a constant-voltage power supply in which the voltage of the battery 11 is reduced to a predetermined constant voltage Vcc (for example, 5 V) is provided in the driving device of the electric tool 10. I have. The constant voltage power supply (Vcc) is used as a power supply for operating a predetermined circuit in the driving device including the control unit 20.

The trigger switch (speed setting unit) 12 is an operation part for rotating the motor 16 of the electric tool 10 at a rotation speed according to the operation amount (retraction amount), and as shown in FIG. Including vessel. The variable resistor has one end connected to the constant voltage Vcc and the other end connected to the ground line. The trigger switch 12 is configured as a so-called potentiometer, and inputs a voltage (trigger operation amount signal) corresponding to the operation amount of the trigger switch 12 to the trigger operation amount signal input port of the control unit 20 using the constant voltage Vcc as a power supply. I do.

The gate circuit 13 constitutes a switching circuit together with the FET array 14, and is provided for individually turning on / off each switching element 14a in the FET array 14, as shown in FIG. The six gate drivers 13a included in the gate circuit 13 are controlled by the control unit 20.

As shown in FIG. 1, the FET array 14 connects a terminal of each phase of the motor 16 to the positive terminal of the battery 11 and a terminal of each phase of the motor 16 and the negative terminal of the battery 11. It is configured as a half-bridge circuit including six switching elements 14a including a low-side switch to be connected.

{Circle around (1)} The switching element 14a configuring the FET array 14 is configured by an n-channel FET. Each switching element 14a is connected to a gate circuit 13 that turns on each switching element 14a by applying a drive voltage equal to or greater than a threshold value between the gate and the source.

The current detection resistor 15 is provided for detecting a current flowing through the motor 16, and is connected to a current calculation unit 25 described later, as shown in FIG.
As shown in FIG. 1, the motor 16 is configured by a three-phase (U-phase, V-phase, W-phase) brushless motor, and a terminal of each phase is connected to a battery 11 as a DC power supply via an FET array 14. It is connected to the. The motor 16 has three coils 16a, three Hall ICs (or Hall elements) 16b, and a rotor 16c.

The coil 16a is provided for each of three phases (U-phase, V-phase, and W-phase), and is located at a position close to the rotor 16c on the rotor side and on the stator side.

The Hall IC (or Hall element) 16b outputs a pulse signal to the control unit 20 via the magnetic pole position detection circuit 17 according to the rotational position of the motor 16 (ie, every time the motor 16 rotates a predetermined amount). .

The rotor 16c is equipped with a tip tool such as a drill, and as shown in FIG. 1, is configured by embedding a permanent magnet including a pair of N poles and a pair of S poles. And are arranged facing each other.

As shown in FIG. 1, the magnetic pole position detection circuit 17 detects the positional relationship between the three-phase (U-phase, V-phase, and W-phase) coils 16a and the rotor 16c based on the output signals of the three Hall ICs 16b. I do. Then, the magnetic pole position detection circuit 17 transmits the detection result to the control unit 20 (the rotation counter 23).

The trial switch 18 is, for example, a button-type switch provided on the outer surface of the power tool 10. The trial switch 18 is connected to the work mode estimating unit 24 as shown in FIG. 1, and when operated by the user, the trial switch 18 performs a trial for estimating the work mode. Send the signal to execute the mode.

The control unit 20 controls the rotational driving of the motor 16 according to the control conditions when the motor 16 of the electric tool 10 is rotationally driven.
In the power tool 10 of the present embodiment, the control unit 20 calculates the rotation position and the current speed of the motor 16 based on a pulse signal from the magnetic pole position detection circuit 17 that detects the rotation position of the motor 16. Then, the control unit 20 performs PWM (Pulse Width Modulation) control on the motor 16 so that the current rotation speed matches a target rotation speed determined by the operation amount of the trigger switch 12.

Here, when the trigger switch 12 is turned on by operating the trigger switch 12, the control unit 20 controls each switching element 14a in the FET array 14 via the gate circuit 13 based on the detection signal from the Hall IC 16b included in the motor 16. Is turned ON / OFF. Thus, the control unit 20 controls the current supplied to the coil 16a of each phase of the motor 16 to rotate the motor 16 in a predetermined direction at a predetermined rotation speed. Then, the control unit 20 inputs a control signal for driving each switching element 14a to the gate circuit 13.

The trigger operation amount signal taken into the control unit 20 is input to the table reference unit 21 and is converted into an output duty by referring to a table of each work mode stored in the storage unit 26.

FIG. 2A shows an example of a target rotation speed table indicating the relationship between the operation amount of the trigger switch 12 and the target rotation speed. As shown in the graph of FIG. 2B, the target rotation speed of the motor 16 with respect to the operation amount of the trigger switch 12 is set to increase (partially unchanged) as the operation amount increases.

In the power tool 10 of the present embodiment, when the user operates the trigger switch 12 (for example, when the user pulls a small amount), the output Duty is set according to the trigger operation amount signal from the variable resistor, and the motor 16 is driven. PWM control is started. That is, the drive duty ratio of the FET array 14 is adjusted such that the larger the operation amount of the trigger switch 12 is, the higher the speed of the motor 16 is rotated, that is, the higher the drive duty ratio is.

In addition, in the power tool 10 of the present embodiment, the control unit 20 controls the commutation of the motor 16 based on the pulse signal from the Hall IC 16b and counts the number of pulses. Further, the control unit 20 performs PWM control of the motor 16 based on the operation amount of the trigger switch 12, the “trigger switch operation amount-output duty table”, and various operation modes stored in the storage unit 26 in advance.

More specifically, as illustrated in FIG. 1, the control unit 20 includes a table reference unit 21, an operation amount calculation unit 22, a rotation counter 23, a work mode estimation unit 24, a current calculation unit 25, a storage unit 26, and a PWM. The signal generator 27 is provided.

The table reference unit 21 corresponds to the current operation amount of the trigger switch 12 with reference to the target rotation speed table (graph) stored in the storage unit 26 (see FIGS. 2A and 2B). Find the target rotation speed. Then, the table reference unit 21 transmits the target rotation speed to the operation amount calculation unit 22.

Further, the table reference unit 21 receives a table designation signal from a work mode estimating unit 24, which will be described later, and sets a target rotation speed table (for example, a gradient of a graph or the like) corresponding to the work mode estimated by the work mode estimating unit 24. Is specified. The work mode estimation performed by the work mode estimating unit 24 will be described later in detail.

The operation amount calculation unit 22 receives the target rotation speed of the motor 16 corresponding to the operation amount of the trigger switch 12 received from the table reference unit 21, and causes the PWM signal generation unit to rotate the motor 16 at the target rotation speed. The duty ratio is transmitted to 27. When the operation mode estimated by the operation mode estimating unit 24 is a specific operation mode and satisfies a predetermined stop condition, the operation amount estimating unit 24 controls the rotation of the motor 16 from the operation mode estimating unit 24. Receiving a stop control signal for stopping the operation. The stop control will be described later in detail.

The rotation counter 23 is connected to the magnetic pole position detection circuit 17 and calculates the current actual rotation speed of the motor 16 based on the detection result received from the magnetic pole position detection circuit 17. Then, the rotation counter 23 transmits the calculated actual rotation speed to the storage unit 26.

When receiving the signal for executing the trial mode received from the trial switch 18, the work mode estimating unit 24 reads the current value and the rotation pulse of the motor 16 acquired in the trial mode from the storage unit 26, and estimates the work mode. I do.

Here, in the present embodiment, the work mode estimated by the work mode estimating unit 24 includes, for example, a tex mode, a bolt tightening mode, a bolt loosening mode, a strong mode, a medium mode, a weak mode, an iron work mode, and a woodwork mode. included.

The text mode is a mode for performing an operation using the text screw (see FIG. 12A), and is controlled so as to reduce a load on the screw head of the text screw due to excessive tightening.

The bolt tightening mode is a mode for performing a bolt tightening operation (see FIG. 13A), and it is assumed that the load torque is small from the beginning of the work, and the load torque increases when the tightening is completed. Control is performed.

The bolt loosening mode is a mode for performing the work of loosening the fastened bolt (see FIG. 14A), and the load torque is large at the beginning of the work, and the load torque decreases at a stretch when the bolt is loosened. The control is performed on the assumption that this is the case.

The strong mode is, for example, a mode for performing an operation using a long screw or the like, and is controlled so as to rotate faster than a default setting from the start of the operation.
The medium mode is, for example, a mode for performing an operation such as attaching a gypsum board or fastening a screw to a decorative material (see FIG. 15A), and rotates at a lower speed than the default setting. Controlled.

The weak mode is, for example, a mode for performing an operation such as fastening a screw to finish the gypsum board, and is controlled so as to rotate at a lower speed than the setting of the middle mode.
The ironsmith mode is a mode for performing an operation using an ironsmith drill (see FIG. 16A), and is controlled so as to start tightening slowly at the beginning of the operation and gradually increase the rotation speed. You.

The woodworking mode is a mode for performing work using a woodworking drill (see FIG. 17 (a)), and starts tightening slowly at the beginning of the work, and gradually rotates at a lower rotation speed than the ironworking mode. It is controlled to increase the speed.

In the power tool 10 of the present embodiment, as a result of performing the work in the trial mode set by operating the trial switch 18, the work mode estimation is performed using the characteristic values (current value and rotation pulse) of the motor 16 acquired. The unit 24 estimates an optimal operation mode for the operation. The work mode estimation process will be described later in detail.

The current calculator 25 is connected between the FET array 14 and the current detection resistor 15 and calculates the current flowing through the motor 16 as shown in FIG. Then, the current calculation unit 25 transmits the calculation result (current value) to the storage unit 26.

The storage unit 26 stores the table indicating the relationship between the operation amount of the trigger switch 12 and the target rotation speed of the motor 16 shown in FIG. 2A, and the operation amount and the output Duty of the trigger switch 12 shown in FIG. Save a table showing the relationship. Further, in the present embodiment, the storage unit 26 stores the rotation pulse of the motor 16 received from the rotation counter 23, the current value of the motor 16 received from the current calculation unit 25, and a control method of the power tool 10 described later. Save the control program.

The PWM signal generation unit 27 refers to the table of each work mode stored in the storage unit 26 based on the trigger operation amount signal of the trigger switch 12 received from the table reference unit 21 and converts the table into the output duty. .
Further, after the work mode is estimated by the work mode estimation unit 24, the PWM signal generation unit 27 outputs an output Duty according to the estimated work mode.

<Estimation of work mode>
In the power tool 10 according to the present embodiment, the work mode optimal for the work is estimated by using the current value and the rotation pulse acquired during the work performed in the trial mode, according to the flowchart shown in FIG. I do. Then, the work is performed in the work mode automatically set based on the estimation result.

That is, in step S1, the initialization is performed when the charged battery 11 is connected to the power tool 10.
The initial setting is performed according to the flowchart shown in FIG.

Specifically, in step S11, the trial result data is reset.
In step S12, a process of clearing the rotation counter 23 is performed. Thereby, various initialization processes necessary for the operation of the control unit 20 are performed.

When the initial setting is completed, the process returns to the flowchart shown in FIG.
In step S2, the control unit 20 waits until the trigger switch 12 is operated by the user and turned on. Here, when the trigger switch 12 is operated by the user, the process proceeds to step S3.

In step S3, it is determined whether or not the trial switch 18 has been operated to be in the ON state. Here, when the trial switch 18 is ON, the process proceeds to step S9, and the trial mode is executed. On the other hand, if the trial switch 18 is not ON, the process proceeds to step S4.

In step S4, since the trial switch 18 is in the OFF state, it is confirmed whether trial result data is held. Here, when the trial result data is held, the process proceeds to step S10, and the trial result execution mode is executed. On the other hand, if the trial result data is not held, the process proceeds to step S5.

In step S5, the operation amount of the trigger switch 12 is read. Specifically, the potential divided by the resistance of the trigger switch 12 is taken into the control unit 20 via the A / D converter.

In step S6, an output duty proportional to the read operation amount of the trigger switch 12 is output (see FIGS. 5A and 5B).
In step S7, the processing from step S5 to step S7 is repeated until the trigger switch 12 is no longer operated.

Then, in step S7, when the trigger switch 12 is opened (OFF state), an output Duty = 0 is output.
In step S8, after the rotation of the motor 16 is stopped, the process returns to step S2, and the processing after step S2 is repeated.

Next, the process in the case where the trial switch 18 is operated in the step S3 to be in the ON state and the trial mode of the step S9 is executed will be described with reference to the flowchart shown in FIG.

In step S21, the control unit 20 resets the output pulse counter of the magnetic pole position detection circuit 17.
In step S22, the control unit 20 reads the operation amount of the trigger switch 12. That is, the control unit 20 takes in the potential divided by the resistance by the trigger switch 12 via an A / D converter (not shown).

In step S23, the control unit 20 outputs an output Duty proportional to the read operation amount of the trigger switch 12.
In step S24, the control unit 20 causes the storage unit 26 to store the current value of the motor 16 calculated by the current calculation unit 25 and the number of rotations obtained by the rotation counter 23 as time-series data.

In step S25, when the state in which the trigger switch 12 is operated (ON state) is continued, the process returns to step S22, and the subsequent operations are repeated. On the other hand, when the trigger switch 12 is open (OFF state), the control unit 20 outputs the output Duty = 0 and stops the rotation of the motor 16.

Subsequently, when the trial switch 18 is operated in step S3 to be turned on and trial result data is present in step S4, the process of executing the trial result execution mode in step S10 will be described with reference to the flowchart shown in FIG. Will be explained.

First, in the trial result execution mode, in step S9, after the trial mode is executed, time series data of the current value of the motor 16 acquired in the trial mode and the rotation pulse acquired from the rotation counter 23 is used. , And the following five values are extracted.
(1) Current value i _on 0.5 second after the load state (first current value)
The presence or absence of a load is determined by setting a threshold value for the current value (for example, 1.0 A).
(2) The current value 0.5 seconds before the point when the load state changes to the no-load state is i _off (second current value)
(3) Assuming that the total load time is T _all , the current value at the time when T _all 1/3 has elapsed from the point of the load state is i ₁ (third current value)
(4) Assuming that the total load time is T _all , the current value at the time when T _all 2/3 has elapsed from the time when the load state is reached is i ₂ (fourth current value)
(5) Total number of rotations N under load (rotation pulse is counted)
Specifically, in step S31, the control unit 20, the motor 16 is to extract a current value _{i on} the 0.5 second after a loaded conditions.

In step S32, the control unit 20 extracts the current value i _off 0.5 seconds before the time when the motor 16 changes from the loaded state to the unloaded state.
In step S33, the control unit 20, when the organic load total time of the motor 16 and the _{T all,} from the time when a loaded _conditions to extract the current _{i 1} of the _T all 1/3 elapsed time.

In step S34, the control unit 20, when the organic load total time of the motor 16 and the _{T all,} from the time when a loaded _conditions to extract the current value _{i 2} of the _T all 2/3 elapsed time.
In step S35, the control unit 20 counts the number of rotation pulses of the motor 16 in the loaded state, and extracts the total number of rotations N.

At step S36, the control unit 20 executes a fuzzy inference, obtained is extracted from the characteristic values of the motor 16 was the above five values in trial mode _{_{_{(i on, i off, i}}} 1, i 2, N) a To estimate the optimal work mode for the work.
In step S37, the control unit 20 stores the result (estimated work mode) of executing the trial mode in the storage unit 26, and ends the process.

<Fuzzy reasoning>
As described above, the power tool 10 of the present embodiment uses fuzzy inference when estimating the work mode.

In estimating the work mode using fuzzy inference, first, the following four feature amounts i _on , i _off , i ₁ / i ₂ , N calculated from the five values obtained earlier are shown in FIG. It is defined as a membership function corresponding to each of the operation modes shown in FIGS.

Note that the membership functions shown in FIGS. 8A to 8D indicate the degree of conformity of each work mode by a degree (0 to 1.0).
By using the membership function of fuzzy inference as described above, the fitness of each work mode can be linked to the characteristic values (current value, rotation pulse) acquired during the actual work.

As described above, the following eight work modes are assumed as the work modes estimated in the present embodiment.
(A) Text mode (screw screw)
(B) Bolt tightening mode (c) Bolt loosening mode (d) Strong mode (long screw, coach screw)
(E) Medium mode (plaster board, decorative material applied)
(F) Weak mode (small diameter machine screw)
(G) Iron work mode (drill for iron work)
(H) Woodworking mode (woodworking drill)
In the membership functions shown in FIGS. 8 (a) to 8 (d), a portion where each work mode is described above and below means that lines indicating these work modes are overlapped.

では In fuzzy inference, four feature values are applied to a membership function to find a matching point for each work mode. Next, the four matching points are summed for each work mode. Then, the work mode in which the sum of the matching points becomes the maximum is stored as the trial result.

Note that the current value _ion and the eight working modes are represented in the membership function as shown in FIG.
That is, in FIG. 8A, when the current value _ion is as small as 5 A or less, the matching point of (b) the bolt tightening mode or (f) the weak mode is added. Then, when the current value _{i on} is in the range of 2 ~ 10A is, (a) tex mode, (d) strong mode, (e) Medium mode, (h) Woodworking mode, (g) fit points Tekko mode Is added. Then, when the current value i _on is as large as more than 18A is subject to adaptation point (c) bolt loosening mode.

The current value i _off and the eight working modes are expressed in the membership function as shown in FIG. 8B.
That is, in FIG. 8B, when the current value i _off is as small as 10 A or less, the matching points of (c) the bolt loosening mode and (h) the woodworking mode are added. When the current value i _off is equal to or less than 20 A, the matching points of (f) weak mode and (g) iron work mode are added. Further, when the current value i _off is in the range of 10 to 30 A, the (e) medium mode matching point is added. If the current value i _off is in the range of 10 to 40 A, the (a) text mode matching point is added. Further, when the current value i _off is equal to or more than 20 A, the matching points of (b) the bolt tightening mode and (d) the strong mode are added.

The current value ratio (i ₁ / i ₂ ) and the eight working modes are expressed in the membership function as shown in FIG. 8C.
That is, in FIG. 8C, when i ₁ / i ₂ is smaller than 0.8, the matching points of (d) strong mode and (g) ironwork mode are added. When i ₁ / i ₂ is in the range of 0.7 to 0.9, the matching points of (e) medium mode and (h) woodworking mode are added. Further, when i ₁ / i ₂ is in the range of 0.85 to 1.0, the (f) weak mode adaptation point is added. Further, when i ₁ / i ₂ is in the range of 0.9 to 1.1, the matching points of (b) bolt tightening mode and (c) bolt loosening mode are added. If i ₁ / i ₂ is equal to or greater than 1.0, the (a) text mode matching point is added.

The total number of revolutions N and the eight working modes are expressed in the membership function as shown in FIG.
That is, in FIG. 8D, when the total number of revolutions N is smaller than 6, the adaptation point of (c) the bolt loosening mode is added. If the total number of revolutions N is smaller than 9, the (f) weak mode matching point is added. Further, when the total number of revolutions N is in the range of 4 to 11, (a) the text mode matching point is added. When the total number of revolutions N is in the range of 7 to 15, the matching points of (e) medium mode and (h) woodworking mode are added. Further, when the total number of revolutions N is larger than 11, the matching points of (d) strong mode and (g) ironing mode are added. Further, when the total number of rotations N is larger than 12, an adaptation point in the (b) bolt tightening mode is added.

Here, in the fuzzy inference, the calculation of the fitness of each work mode will be specifically described as follows.
Here, as shown in FIG. 9, four feature amounts _{_{_{(i on, i off, i}}} 1 / i 2, N) for each, 3A, 12A, 9/4 = 2.3,8 If the description I do.

Four feature values, the result of calculating the fitness of each work mode, as shown in FIG. 9, for i _on, (a) fit the vertex mode 0.2, (b) bolted mode, ( e) Medium mode, (h) Woodworking mode had a suitability of 0.3, (f) Low mode had a suitability of 0.6, and other work modes had a suitability of 0.

These fitness levels can be obtained from the membership functions shown in FIGS. 10 (a) to 10 (d).
Of the four feature amounts, for the current value _{i on,} as shown in FIG. 10 (a), (a) the vertex mode fitness is 0.2, (b) bolted mode, (e) Medium mode, (H) The fitness of the woodworking mode was 0.3, the fitness of the weak mode was 0.6, and the fitness of the other work modes was 0.

Next, as for the current value i _off , as shown in FIG. 10B, (e) the fitness of the medium mode is 0.1, (a) the fitness of the tex mode is 0.2, and (f) is weak. The suitability of the mode and (g) iron work mode was 0.6, and the suitability of the other work modes was 0.

Next, as for i ₁ / i ₂ , as shown in FIG. 10C, (a) the suitability of the tex mode was 1.0, and the suitability of the other work modes was 0.
Next, regarding the total number of revolutions N, as shown in FIG. 10 (d), the conformity of (e) medium mode, (f) weak mode, (h) woodworking mode is 0.3, and (a) text mode. Of the other work modes was 0.

The fitness of each work mode calculated using the above four feature amounts is as shown in FIG.
(A) Tex mode = 2.3
(B) Bolt tightening mode = 0.3
(C) Bolt loosening mode = 0
(D) Strong mode = 0
(E) Medium mode = 0.7
(F) Weak mode = 1.5
(G) Iron work mode = 0.6
(H) Woodworking mode = 0.6
Met.

In the power tool 10 of the present embodiment, as described above, by determining the fitness of each work mode as a numerical value, the work mode with the largest numerical value has the highest possibility and is used as the estimation result. Therefore, in the above example, the (a) tex mode having the highest fitness of 2.3 is estimated.

Therefore, in the trial result execution mode of step S10 shown in FIG. 3, a graph showing the relationship between the operation amount of the trigger switch 12 and the output duty corresponding to the (a) tex mode estimated in the trial mode of FIG. Is selected, and the motor 16 can be controlled according to the optimum control conditions.

That is, as shown in FIG. 11, in the estimated (a) tex mode, the output Duty is adjusted so that the rotation speed becomes low immediately after the start of the work as compared with the default graph, and the operation amount of the trigger switch 12 is reduced. When the duty is increased, the output Duty is gradually increased after a period in which the output Duty is constant. When the output Duty reaches 70%, the output is controlled so as not to exceed it.

(4) With this, when performing the work using the text screw, it is possible to solve an operation problem such as skipping the screw head by overtightening the text screw and performing an appropriate work. In addition, by controlling the motor 16 according to a table or a graph (see FIG. 11) corresponding to the work mode estimated using the current value and the rotation pulse acquired during the trial mode, the workability of each work is improved. Can be done.

In addition, in the graph shown in FIG. 11, in addition to the graph for default, (a) tex mode, (b) bolt tightening mode, (c) bolt loosening mode, (d) strong mode, (e) medium mode, (e) The graphs for f) weak mode, (g) ironwork mode, and (h) woodwork mode are shown.
In FIG. 11, it is assumed that the graph for the bolt tightening mode (b) and the graph for the bolt loosening mode (c) are displayed in an overlapping manner.

<Characteristics of each work>
In the power tool 10 of the present embodiment, the work mode is estimated according to the following fuzzy rules using the current value and the rotation pulse acquired in the trial mode.

Rule (1) When the rotation speed of the motor 16 is high, the current value is small, and the current value suddenly rises at the end, it is estimated that the work is “bolting”.
Rule (2) If the rotational load of the motor 16 is extremely large from the beginning of the work and then drops at once, and there is no current peak until the trigger switch 12 is turned off, it is estimated that the work is "bolt loosening".

When the rotation load of the motor 16 is small at the beginning of the operation of the rule (3), gradually increases after that, and then suddenly increases (short end), it is estimated that the operation is “screw tightening”.
When the rotation load of the motor 16 is large at the beginning of the operation of the rule (4), and then gradually decreased, and then suddenly decreased (exit), it is assumed that the operation is "loosening (unscrewing)".

When the rotation load of the motor 16 is small at the beginning of the operation of the rule (5) and then gradually increases, it is assumed that the operation is “drilling a hole in a thick plate”.
If the rotation load of the motor 16 is small at the beginning of the operation of the rule (6), then gradually increases, and finally decreases suddenly (exit), it is assumed that the operation is “drilling a thin plate”.

In the present embodiment, the work mode is estimated based on the fuzzy rules (1) to (6) using the following characteristic values (current value, rotation speed, etc. of the motor 16) acquired during each work. Done.
In the following description, the case where the (d) strong mode and the (f) weak mode are estimated is almost the same as that of the (e) medium mode, and thus the description thereof is omitted.

(A) Text mode The text mode is a mode in which a driver is mounted as a tip tool and a work (see) using a text screw is performed as shown in FIG. The load is controlled so as to reduce the load on the screw head of the tex screw due to the overshoot.

As shown in FIG. 12 (b), the operation using the texture screw is performed in four stages of contact with the surface of the work material, drilling a pilot hole, tapping, and tightening.
At this time, as shown in FIG. 12 (c), the current value of the motor 16 rises after the tex screw comes into contact with the surface of the work material, and when the process proceeds to the preparation of the pilot hole, the rate of rise becomes gentle. Then, when the current value of the motor 16 shifts to tapping, the current value sharply decreases and then gradually increases, and then, in the tightening operation, the current value rapidly increases and then becomes constant.

Also, as shown in FIG. 12 (c), the rotation speed of the motor 16 starts to increase from the state where the tex screw is in contact with the surface of the work material, and then gradually decreases when the process proceeds to the preparation of the pilot hole. When the operation shifts to tapping, the current value suddenly drops, then gradually rises, and then rapidly rises again in the tightening operation.

Further, as shown in FIG. 12 (d), the trigger switch 12 during the operation shifts to the ON state at the same time as the start of the operation, and when the tightening operation is completed, in order to prevent the screw head of the tex screw from jumping. Automatically transition to the OFF state by the stop control.

Further, the direction switch for switching the rotation direction of the motor 16 during the operation is on the normal rotation side as shown in FIG.
As described above, in the text mode, the current value and the rotation speed of the motor 16 change as shown in FIG. Therefore, in the trial mode, the current value i _on (first current value) 0.5 seconds after the above-described loaded state, and 0.5 seconds before the change from the loaded state to the no-load state. _Is the current value of i _off (the second current value), and the total load time is T _all, and the current value at the time when T _all 1/3 elapses from the load state is i ₁ (the third current value). Value), when the total load time is T _all , the current value at the elapse of T _all 2/3 from the point of the load state is i ₂ (the fourth current value), and By calculating four characteristic amounts i _on , i _off , i ₁ / i ₂ , and N from five values of the total number of rotations N (integrated count of rotation pulses), these four characteristic amounts are used for text work. If the characteristics are met, this work is determined to be work using a text screw, and The tex mode can be estimated to be optimal for the industry.

Then, when the actual work is performed, the work is performed in a state where the “graph indicating the relationship between the operation amount of the trigger switch 12 and the output duty” corresponding to the text mode shown in FIG. 11 is selected. Thus, it is possible to perform the motor control optimal for the operation using the text screw.

(B) Bolt tightening mode The bolt tightening mode is a mode for mounting a socket as a tool bit and tightening a bolt and a nut as shown in FIG. The control is performed on the assumption that the load torque is small and the load torque increases when the tightening is completed.

Specifically, as shown in FIG. 13B, the current value of the motor 16 during the bolting operation changes at a low current value from the start of the operation, and rises sharply when the operation shifts to the tightening operation. Is shown.

Further, as shown in FIG. 13 (b), the rotation speed of the motor 16 rises rapidly from the beginning of the work, remains almost constant at a high value until the tightening work, and rapidly decreases when the work shifts to the tightening work. It shows the characteristic of doing.

Further, as shown in FIG. 13C, the trigger switch 12 during the operation shifts to the ON state simultaneously with the start of the operation, and shifts to the OFF state when the tightening operation is completed.
Further, the direction switch for switching the rotation direction of the motor 16 during the operation is on the normal rotation side as shown in FIG.

As described above, in the bolting operation, the current value and the rotation speed of the motor 16 change as shown in FIG. Therefore, in the trial mode, the current value i _on (first current value) 0.5 seconds after the above-described loaded state, and 0.5 seconds before the change from the loaded state to the no-load state. _Is the current value of i _off (the second current value), and the total load time is T _all, and the current value at the time when T _all 1/3 elapses from the load state is i ₁ (the third current value). Value), when the total load time is T _all , the current value at the elapse of T _all 2/3 from the point of the load state is i ₂ (the fourth current value), and By calculating four characteristic amounts i _on , i _off , i ₁ / i ₂ , and N from five values of the total number of rotations N (counting the number of rotation pulses), these four characteristic amounts are bolted. If these characteristics are met, this work is determined to be bolting work, and It can be estimated that the bolting mode is optimal.

When the actual work is performed, the work is performed in a state in which the “graph indicating the relationship between the operation amount of the trigger switch 12 and the output duty” corresponding to the bolt tightening mode shown in FIG. 11 is selected. By doing so, it is possible to perform optimal motor control for bolting work.

(C) Bolt loosening mode The bolt loosening mode is a mode for mounting a socket as a tip tool and performing a work of loosening the fastened bolts and nuts as shown in FIG. Initially, control is performed on the assumption that the load torque is large, and that the load torque drops at once if the bolt is loosened.

Specifically, as shown in FIG. 14B, the current value of the motor 16 during the bolt loosening operation changes at a high current value from the start of the operation to loosen the bolt in the fastened state, and the bolt is loosened. It shows a characteristic that when it shifts to the state where it has been moved, it drops sharply.

Also, as shown in FIG. 14B, the rotation speed of the motor 16 gradually increases from 0 at the beginning of the work, and when the bolt shifts to a loosened state, the rotation load suddenly decreases. Shows the characteristic of rising.

Further, as shown in FIG. 14 (c), the trigger switch 12 during the operation shifts to the ON state simultaneously with the start of the operation, and when the bolt shifts to the loosened state, the loosened bolt (or nut) is dropped. In order to prevent this, the state automatically shifts to the OFF state by the stop control described later.

Further, the direction switch for switching the rotation direction of the motor 16 during the operation is on the reverse rotation side as shown in FIG.
As described above, in the bolt loosening operation, the current value and the rotation speed of the motor 16 change as shown in FIG. Therefore, in the trial mode, the current value i _on (first current value) 0.5 seconds after the above-described loaded state, and 0.5 seconds before the change from the loaded state to the no-load state. _Is the current value of i _off (the second current value), and the total load time is T _all, and the current value at the time when T _all 1/3 elapses from the load state is i ₁ (the third current value). Value), when the total load time is T _all , the current value at the elapse of T _all 2/3 from the point of the load state is i ₂ (the fourth current value), and By calculating four characteristic amounts i _on , i _off , i ₁ / i ₂ , and N from five values of the total number of rotations N (integrated count of rotation pulses), these four characteristic amounts can be used to loosen bolts. If the above characteristics are met, this work is determined to be bolt loosening work, and It can be estimated that the bolt loosening mode is optimal.

When the actual work is performed, the work is performed in a state in which the “graph indicating the relationship between the operation amount of the trigger switch 12 and the output duty” corresponding to the bolt loosening mode shown in FIG. 11 is selected. By doing so, it is possible to carry out optimal motor control for bolt loosening work.

(E) Medium mode In the medium mode, a driver is mounted as a tip tool, and as shown in FIG. 15 (a), for example, using a tapping screw or the like to paste a plaster board or a decorative material on which a pilot hole has been formed. This is a mode for performing work such as screw tightening, and is controlled to rotate at a slightly lower speed than the default setting.

Specifically, as shown in FIG. 15B, the current value of the motor 16 during the screw tightening operation changes at a low current value due to a small rotation load at the start of the operation, and the screw moves into the prepared hole. It shows the characteristic that the current value gradually rises as it enters, and rises sharply when it shifts to the tightening operation.

Further, as shown in FIG. 15B, the rotation speed of the motor 16 rapidly increases at the beginning of the work due to a small rotation load, and gradually decreases as the screw enters the pilot hole. When the operation shifts to the tightening operation, it shows a characteristic of rapidly increasing.

Further, as shown in FIG. 15C, the trigger switch 12 during the operation shifts to the ON state at the same time as the start of the operation, and shifts to the OFF state when the screw tightening operation is completed.
Further, the direction switch for switching the rotation direction of the motor 16 during the operation is on the normal rotation side as shown in FIG.

As described above, in the screw tightening operation, the current value and the rotation speed of the motor 16 change as shown in FIG. Therefore, in the trial mode, the current value i _on (first current value) 0.5 seconds after the above-described loaded state, and 0.5 seconds before the change from the loaded state to the no-load state. _Is the current value of i _off (the second current value), and the total load time is T _all, and the current value at the time when T _all 1/3 elapses from the load state is i ₁ (the third current value). Value), when the total load time is T _all , the current value at the elapse of T _all 2/3 from the point of the load state is i ₂ (the fourth current value), and By calculating four characteristic amounts i _on , i _off , i ₁ / i ₂ , and N from five values of the total number of rotations N (counting the number of rotation pulses), these four characteristic amounts can be screwed down. If these characteristics are met, this work is determined to be screw tightening work, and The mode can be estimated to be optimal.

Then, when the actual work is performed, the work is performed in a state where the “graph indicating the relationship between the operation amount of the trigger switch 12 and the output duty” corresponding to the middle mode shown in FIG. 11 is selected. Thus, it is possible to perform the optimal motor control for the screw tightening operation.

(G) Iron work mode The iron work mode is a mode for performing a work of processing iron or the like using a drill for iron work as a tip tool as shown in FIG. At first, the rotation speed is controlled to be gradually increased.

Specifically, the current value of the motor 16 during the work using the iron drill is gradually increased from the start of the work as shown in FIG. As the current progresses, the current value gradually increases, and when it penetrates through the work material, the rotating load sharply decreases, so that the current value sharply decreases.

Further, as shown in FIG. 16 (b), the rotation speed of the motor 16 rises to a constant rotation speed from the beginning of the work and then remains almost constant. It shows the characteristic that it suddenly rises because of the decrease.

Further, as shown in FIG. 16C, the trigger switch 12 during the operation shifts to the ON state at the same time as the start of the operation, and shifts to the OFF state when the iron drill passes through the work material.
Further, the direction switch for switching the rotation direction of the motor 16 during the operation is on the normal rotation side as shown in FIG.

As described above, in the operation using the iron drill, the current value and the rotation speed of the motor 16 change as shown in FIG. Therefore, in the trial mode, the current value i _on (first current value) 0.5 seconds after the above-described loaded state, and 0.5 seconds before the change from the loaded state to the no-load state. _Is the current value of i _off (the second current value), and the total load time is T _all, and the current value at the time when T _all 1/3 elapses from the load state is i ₁ (the third current value). Value), when the total load time is T _all , the current value at the elapse of T _all 2/3 from the point of the load state is i ₂ (the fourth current value), and By calculating four characteristic amounts i _on , i _off , i ₁ / i ₂ , and N from five values of the total number of rotations N (counting the number of rotation pulses), these four characteristic amounts are converted into iron drills. If the characteristics of the work using the drill are met, this work is performed using the drill for ironsmith. It can be determined that the iron work mode is optimal for the work.

Then, when the actual work is performed, the work is performed in a state in which the “graph indicating the relationship between the operation amount of the trigger switch 12 and the output duty” corresponding to the ironwork mode shown in FIG. 11 is selected. Thus, it is possible to perform the motor control optimal for the operation using the iron drill.

(H) Woodworking mode The woodworking mode is a mode for performing woodworking work using a woodworking drill as a tool bit as shown in FIG. 17 (a). Control is performed so that the rotation speed is gradually increased at a rotation speed lower than the ironwork mode.

Specifically, the current value of the motor 16 during the work using the woodworking drill gradually increases from the start of the work, as shown in FIG. Even if it advances, it keeps almost constant, and when it penetrates the work material, it shows the characteristic that the rotational load drops sharply and drops sharply.

Also, as shown in FIG. 17 (b), the rotation speed of the motor 16 rises to a constant rotation speed from the beginning of the operation and then remains almost constant. It shows the characteristic that it goes up because it goes down.

Also, the trigger switch 12 during the operation shifts to the ON state at the same time as the start of the operation as shown in FIG. 17C, and shifts to the OFF state when the woodworking drill penetrates the work material.
Further, the direction switch for switching the rotation direction of the motor 16 during the operation is on the normal rotation side as shown in FIG.

Here, when comparing the (g) iron work mode with the (h) wood work mode, as shown in FIG. 16 (b) and FIG. 17 (b), the hardness of the processed materials (iron and wood) is different. The current using the motor 16 during processing is larger and the rotation speed is lower in the operation using the drill for ironsmithing than in the operation using the drill for woodworking.

As described above, in the operation using the woodworking drill, the current value and the rotation speed of the motor 16 change as shown in FIG. Therefore, in the trial mode, the current value i _on (first current value) 0.5 seconds after the above-described loaded state, and 0.5 seconds before the change from the loaded state to the no-load state. _Is the current value of i _off (the second current value), and the total load time is T _all, and the current value at the time when T _all 1/3 elapses from the load state is i ₁ (the third current value). Value), when the total load time is T _all , the current value at the elapse of T _all 2/3 from the point of the load state is i ₂ (the fourth current value), and By calculating four characteristic amounts i _on , i _off , i ₁ / i ₂ , and N from five values of the total number of rotations N (integrated count of rotation pulses), these four characteristic amounts are converted into a woodworking drill. If the characteristics match the characteristics of the work using It can be estimated that the woodworking mode is optimal for the work.

Then, when the actual work is performed, the work is performed in a state where the “graph indicating the relationship between the operation amount of the trigger switch 12 and the output duty” corresponding to the woodworking mode shown in FIG. 11 is selected. Thereby, it is possible to perform the motor control optimal for the operation using the woodworking drill.

<Execution of estimated work mode and stop control of motor 16>
The processing in the trial result execution mode of step S10 in FIG. 3 among the control methods performed by the power tool 10 of the present embodiment will be described with reference to the flowchart shown in FIG.

That is, in step S41, the control unit 20 determines whether or not the work mode estimated in the trial mode is one of the (a) text mode and (c) the bolt loosening mode. Here, if the estimated work mode is (a) or (c), the process proceeds to step S45. On the other hand, when the estimated work mode is not (a) or (c), the process proceeds to step S42.

In step S42, since it is determined that the work mode estimated in step S41 is not (a) or (c), the determination of the condition for stopping the motor 16 is not performed. Read the manipulated variable. Specifically, the potential divided by the resistance of the trigger switch 12 is taken into the control unit 20 via the A / D converter.

In step S43, the control unit 20 refers to the “operation amount of trigger switch 12—output duty table” (see FIG. 11) corresponding to each work mode stored in the storage unit 26, and outputs the operation amount.

Thus, by performing the optimal motor control for each of the estimated work modes, the user can always set the optimum work mode without any special operation such as setting the optimum work mode by himself / herself when repeating the same work. It is possible to work comfortably under the motor control setting.

In step S44, when the trigger switch 12 is open (OFF state), the control unit 20 outputs an output Duty = 0 to stop the rotation of the motor 16. On the other hand, when the state in which the trigger switch 12 is operated (ON state) continues, the control unit 20 returns to step S42 and repeats the processing from step S42 to step S44.

On the other hand, if it is determined in step S41 that the work mode estimated is not (a) or (c), the process proceeds to step S45 in order to determine whether a condition for stopping the motor 16 is satisfied. The amount of change in current of the motor 16 per unit time (current change rate) is calculated.

In step S46, it is determined whether or not the amount of change in the current calculated in step S45 satisfies the condition for stopping the rotation of the motor 16 for each estimated working mode.
For example, if (a) the text mode is estimated in step S41, the condition that the current change per unit time (current change rate) becomes 5 A / sec or more is determined as a condition for stopping the rotation of the motor 16. I do.

Therefore, in the estimated (a) text mode, when the stop condition that the current change rate is 5 A / sec or more is satisfied, the control unit 20 outputs the output Duty = 0, and stops the rotation of the motor 16. .

That is, when the work is performed in the estimated (a) text mode, the rotation of the motor 16 is automatically stopped when the current change rate satisfies the stop condition of 5 A / sec or more.
Thereby, when the estimated work mode is the (a) text mode, the control unit 20 determines that a sudden load is applied to the motor 16 (the condition that the current change rate is 5 A / sec or more is satisfied). In this case, the rotation of the motor 16 is stopped regardless of the operation amount of the trigger switch 12. As a result, it is possible to prevent excessive tightening of the tex screw at the time of completion of the operation using the tex screw, and to effectively prevent problems such as screw head jump and breakage.

On the other hand, if (c) the bolt loosening mode is estimated in step S41, the rotation of the motor 16 is stopped until the amount of change in current per unit time (current change rate) becomes -1 A / sec or more. Condition.

Therefore, in the estimated (c) volt loosening mode, if the stop condition that the current change rate is −1 A / sec or more satisfies the condition, the control unit 20 outputs the output Duty = 0 to stop the rotation of the motor 16. Stop.

In other words, when the operation is performed in the estimated (c) bolt loosening mode, the rotation of the motor 16 is automatically stopped when the current change rate satisfies the stop condition of -1 A / sec or more.

As a result, when the estimated work mode is (c) the bolt loosening mode, the control unit 20 causes the load on the motor 16 to drop sharply (satisfies the condition that the current change rate is -1 A / sec or more). When the determination is made, the rotation of the motor 16 is stopped regardless of the operation amount of the trigger switch 12. As a result, it is possible to effectively prevent the bolt (or nut) from dropping off when the bolt loosening operation is completed.

On the other hand, in step S47, since it is determined that the predetermined stop condition is not satisfied in step S46, the condition for stopping the motor 16 is not determined, and the control unit 20 reads the operation amount of the trigger switch 12. Specifically, the potential divided by the resistance of the trigger switch 12 is taken into the control unit 20 via the A / D converter.

In step S48, the control unit 20 refers to the “operation amount of the trigger switch 12—output duty table” (see FIG. 11) corresponding to each work mode stored in the storage unit 26, and outputs the operation amount.

Thereby, by performing the optimal motor control for each of the estimated work modes, the user can always set the optimum work mode without any special operation such as setting the optimum work mode by himself when repeating the same work. It is possible to work comfortably under the motor control setting.

In step S49, when the trigger switch 12 is open (OFF state), the control unit 20 outputs the output Duty = 0 to stop the rotation of the motor 16. On the other hand, when the state in which the trigger switch 12 is operated (ON state) is continued, the control unit 20 returns to step S45 and repeats the processing from step S45 to step S49.

In the power tool 10 according to the present embodiment, as described above, when the same type of work is repeatedly performed, the control unit 20 sets the trial mode to the trial mode in order to automatically set the optimal work mode for the work. The work mode is estimated based on the characteristic values (current value, rotation pulse, and the like) of the motor 16 acquired in the state where the operation is performed.

Normally, a single power tool has a plurality of functions (for example, in the case of a drill driver, screw tightening, nut tightening, hole drilling, etc.). Conventionally, it has been necessary for a user to select an optimal work mode by himself assuming work contents and to manually switch the work mode.

According to the power tool 10 of the present embodiment, by estimating the optimal work mode for the work by using the characteristic values obtained by performing the actual work in the trial mode, the user himself / herself can perform various works. An operation can be performed by automatically selecting an optimal mode for each operation without selecting an appropriate mode.

Therefore, the power consumption of the battery 11 can be reduced by improving the usability of the user and the work efficiency.
Further, by performing the work by selecting the work mode most suitable for the work, work mistakes (failures) are reduced, so that the work yield can be improved and the loss of the work material can be reduced.

In addition, the estimation of the work mode is performed after the trigger switch 12 is turned on in the trial mode, after the trigger switch 12 is turned off, and before the next work is started (the trigger switch 12 is turned on). Is done. For this reason, the load related to the work mode estimation processing of the control unit 20 is small, and it can be realized at low cost.

When the work is switched, by operating a reset button (not shown), the learning contents so far can be erased and returned to the initial state.
[Other embodiments]
As mentioned above, although one Embodiment of this invention was described, this invention is not limited to the said Embodiment, A various change is possible within the range which does not deviate from the summary of this invention.

(A)
In the above embodiment, four feature values i _on , i _off , i ₁ / i ₂ , and N are calculated from the five values i _on , i _off , i ₁ , i ₂ , and N obtained in the trial mode. In the above, the example of estimating the optimal operation mode has been described. However, the present invention is not limited to this.

For example, the optimum work mode may be estimated by combining two, three, four, or six or more of the above five values.
That is, in the present invention, the values acquired in the trial mode are not limited to the above five values, and may be smaller values or larger values.
The values acquired in the trial mode are not limited to the above five types, and other types of values may be used.

(B)
In the above-described embodiment, of the four feature amounts used for estimating the work mode, the current value 0.5 seconds after the load state is reached for i _on and i _off , and the current value for the _on state and the _off state from the load state The description has been given by taking an example in which the current value 0.5 seconds before the time point when the state changes to the no-load state is set to i _off . However, the present invention is not limited to this.

For example, 0.1 second after become loaded conditions or current value after 1.0 seconds may be i _on. Further, a current value 0.1 seconds before or 0.8 seconds after the point of time when the state changes from the loaded state to the unloaded state may be set as i _off .
In other words, the feature amounts i _on and i _off need only be set so that the current value at the time when a change is easily detected for each work mode is used.

(C)
In the above-described embodiment, examples have been described in which the work modes to be estimated include the tex mode, the bolt tightening mode, the bolt loosening mode, the strong mode, the medium mode, the weak mode, the ironwork mode, and the woodwork mode. However, the present invention is not limited to this.
For example, the estimated operation mode is not limited to the above operation mode, and may be an operation mode other than the above operation modes.

(D)
In the above embodiment, an example has been described in which a current value and a rotation pulse are used as the characteristic values of the motor 16 used for estimating the work mode. However, the present invention is not limited to this.
For example, as the characteristic value used for estimating the work mode in the present invention, a characteristic value other than the current value and the rotation pulse may be used.

(E)
In the above embodiment, an example using fuzzy inference when estimating the work mode has been described. However, the present invention is not limited to this.
In the method of controlling a motor of a power tool according to the present invention, the use of fuzzy inference is not essential, and may be implemented by other methods.

(F)
In the above embodiment, an example in which a brushless motor is used as the motor 16 has been described. However, the present invention is not limited to this.
For example, a DC motor other than the brushless motor that is driven to rotate in accordance with the operation amount of the trigger switch may be used.

(G)
In the above-described embodiment, an example has been described in which the present invention is implemented as the power tool 10 and the control method of the power tool 10. However, the present invention is not limited to this.
For example, the present invention may be realized as a control program that causes a computer to execute the control method of the power tool 10 described in the above embodiment.
This control program only needs to be stored in the storage unit 26 shown in FIG. 1, and can be read by the CPU so that the computer can execute the control method described above.

The power tool according to the present invention has an effect that the user can automatically select an optimal mode for each work and perform the work without the user himself selecting a mode suitable for various works. It is widely applicable to electric tools used in various operations.

10 Power tool 11 Battery (power supply)
12 Trigger switch (speed setting section)
13 Gate circuit (switching circuit)
13a Gate driver 14 FET array (switching circuit)
14a Switching element 15 Current detection resistor 16 Motor (DC motor)
16a Coil 16b Hall IC
16c Rotor 17 Magnetic pole position detection circuit 18 Trial switch 20 Control unit 21 Table reference unit 22 Operation amount calculation unit 23 Rotation counter 24 Work mode estimation unit 25 Current calculation unit 26 Storage unit 27 PWM signal generation unit

Claims

A DC motor,
A speed setting unit that sets the rotation speed of the DC motor according to an operation amount;
A switching circuit having a plurality of switching elements and supplying power to the DC motor,
The switching circuit is controlled so as to rotate the DC motor based on the rotation speed set in the speed setting unit, and a trial mode for estimating a work mode is provided. A control unit that estimates the work mode based on the characteristic value of the DC motor,
A power tool equipped with.
The control unit controls the DC motor according to the operation amount of the speed setting unit based on the estimated work mode,
The power tool according to claim 1.
The characteristic value includes at least one of a current value and a rotation pulse of the DC motor obtained in the trial mode,
The power tool according to claim 1.
The control unit includes: a first current value after a predetermined time after the DC motor enters the loaded state; a second current value a predetermined time before the change from the loaded state to the no-load state; when the total time a load state was T all, the ratio of the third current value and T all 2/3 fourth current value of the elapsed time of T all 1/3 elapsed time from the time when the became loaded conditions Estimating the work mode using at least one characteristic amount of the total number of rotations in the loaded state;
The power tool according to claim 3.
A trial switch operated by a user when the trial mode is performed, further comprising:
The power tool according to any one of claims 1 to 4.
The work mode estimated by the control unit includes at least one of a text mode, a bolt tightening mode, a bolt loosening mode, a strong mode, a medium mode, a weak mode, an ironwork mode, and a woodwork mode.
The power tool according to any one of claims 1 to 5.
A storage unit that stores the work mode estimated by the control unit,
The power tool according to any one of claims 1 to 6.
The control unit detects a change in the current value of the DC motor when the estimated work mode is the predetermined work mode, and detects a change in the current value of the DC motor when the rate of the change exceeds a predetermined threshold. Stop rotation,
The power tool according to any one of claims 1 to 7.
The control unit estimates the work mode using fuzzy inference based on the characteristic value acquired in the trial mode.
The power tool according to any one of claims 1 to 8.
It is a control method of the electric tool as described in any one of Claim 1 to 9, Comprising:
In the trial mode, rotating the DC motor under the previously set control conditions,
In the trial mode, obtaining the characteristic value of the DC motor;
Estimating the work mode based on the characteristic value obtained in the trial mode,
The control method of the electric tool provided with.
Controlling the DC motor in accordance with the operation amount of the speed setting unit based on the estimated working mode, further comprising:
A control method for a power tool according to claim 10.
The characteristic value includes at least one of a current value and a rotation pulse of the DC motor obtained in the trial mode,
A method for controlling a power tool according to claim 10.
In the step of estimating the work mode, the first current value after a predetermined time after the DC motor enters the loaded state, and the second current value a predetermined time before the time when the load state changes from the loaded state to the no-load state. value, wherein when the total time a loaded conditions was T all, fourth third current value and T all 2/3 elapse of T all 1/3 elapsed time from the time when the became loaded conditions Estimating the work mode using at least one characteristic amount of a ratio of current values and a total rotation speed in the loaded state;
A method for controlling a power tool according to claim 12.
The estimated work mode includes at least one of a text mode, a bolt tightening mode, a bolt loosening mode, a strong mode, a medium mode, a weak mode, an ironwork mode, and a woodwork mode.
The method for controlling a power tool according to claim 10.
Detecting the change in the current value of the DC motor when the estimated work mode is the predetermined work mode, and stopping the rotation of the DC motor when the rate of the change exceeds a predetermined threshold value; , Further equipped,
The method for controlling a power tool according to claim 10.
The work mode is estimated using fuzzy inference.
A control method for a power tool according to any one of claims 10 to 15.
It is a control program of the electric tool according to any one of claims 1 to 9,
In the trial mode, rotating the DC motor under the previously set control conditions,
In the trial mode, obtaining the characteristic value of the DC motor;
Estimating the work mode based on the characteristic value obtained in the trial mode,
A control program for causing a computer to execute a control method of a power tool having a program.