JP5065215B2 - Power tool and control method thereof - Google Patents

Description

  The present invention relates to an electric tool powered by a motor and a control method thereof.

  Conventionally, electric tools such as an electric drill and an electric screwdriver that use a motor capable of rotating in the forward and reverse directions have been proposed. For example, the electric power tool disclosed in Patent Document 1 includes a direction instruction unit and a driving instruction unit, and when the operation is instructed by the driving instruction unit, the control unit is instructed to rotate by the direction instruction unit. Depending on the direction, the switching element is turned on and off to control the direction of the current supplied to the motor, thereby rotating the motor forward or backward.

First, the control unit reads a signal output from the driving instruction unit at a predetermined interval, and determines the driving instruction when the read values match a plurality of times (for example, three times). After that, the control unit reads the signal output from the direction instruction unit at a predetermined interval, and determines the driving direction when the read values match a plurality of times (for example, three times). Then, the control unit drives the motor in the determined operation direction.
JP 2005-169534 A

  However, in the method of reading and confirming the direction instruction after confirming the driving instruction, it takes time from the operation of the driving instruction unit to the start of driving the motor, and it may be felt that the operability is not good depending on the operator. . If, for example, the number of samplings is reduced in order to shorten this time, a malfunction that rotates in an unintended direction may occur.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide an electric tool having good operability and capable of rotating a motor in an intended direction and a control method thereof. It is in.

  In order to achieve the above object, an invention according to claim 1 is an electric tool powered by a motor capable of normal rotation and reverse rotation, wherein the direction indicating means for indicating the rotation direction of the motor, The operation instruction means for instructing drive / stop alternatively, the instruction of the operation instruction means and the instruction of the direction instruction means are alternately read, and when the instructions of the operation instruction means read a plurality of times coincide with each other Control means for determining the matching instruction when the instructions of the direction indicating means read a plurality of times match after determining the matching instructions, and controlling the drive of the motor in the determined direction of rotation. .

  According to this configuration, by alternately reading the instruction of the driving instruction means and the instruction of the direction instruction means, the period from the confirmation of the instruction by the driving instruction means to the confirmation of the instruction by the direction instruction means is shortened, and the operability is improved. Can be improved. Then, by confirming the instruction by the direction instructing means after the instruction by the driving instructing means is confirmed, the motor can be driven to rotate in the intended direction.

  According to a second aspect of the present invention, in the first aspect, the control unit reads an instruction from the direction instruction unit when a driving instruction is read from the driving instruction unit, and each instruction is used as a first instruction. It is determined whether the first step stored and the instruction read from the driving instruction means and the first instruction match, and if the read instruction matches the first instruction, A second step of reading the direction instruction means, determining whether the read instruction matches the first instruction, and proceeding if the read instruction matches the first instruction; And a third step of driving the motor in the direction instructed by the direction indicating means after executing the second step at least once.

According to this configuration, the instruction by the direction instruction unit can be confirmed after the instruction by the driving instruction unit is confirmed.
According to a third aspect of the present invention, in the second aspect, the control unit counts up the number of instructions when the read instruction matches a first instruction in the second step, and the third step When the number of instructions matches the predetermined value in the step, each instruction is determined.

According to this configuration, it is possible to easily determine that a plurality of instructions by the driving instruction unit match and a plurality of instructions by the direction instruction unit match by the number of instructions.
According to a fourth aspect of the present invention, in the third aspect of the present invention, in the third aspect, the control unit is configured to perform the second step when the instruction read from the driving instruction unit does not coincide with the first instruction, or from the direction instruction unit. When the read instruction does not coincide with the first instruction, the instruction count is cleared.

  According to this configuration, by clearing the number of instructions, it is possible to easily determine that a plurality of instructions by the driving instruction means are continuously matched and a plurality of instructions by the direction instruction means are continuously matched. it can.

According to a fifth aspect of the present invention, in any one of the first to fourth aspects, the control unit does not accept an instruction from the direction indicating unit after driving the motor.
According to this configuration, even if the instruction from the direction indicating unit changes due to noise or the like after driving the motor, it is possible to prevent malfunction caused by the change.

  The invention according to claim 6 is a method for controlling an electric tool powered by a motor capable of normal rotation and reverse rotation, wherein direction indicating means for indicating the rotation direction of the motor, and driving / stopping of the motor are performed. Alternatively, a driving instruction means for instructing, and a control means for driving and controlling the motor in accordance with an instruction from the driving instruction means and an instruction from the direction instructing means, and the control means includes instructions from the driving instruction means When the instructions of the direction instruction means are read alternately, and when the instructions of the driving instruction means read a plurality of times match, after the matching instructions are confirmed, the instructions of the direction instruction means read a plurality of times match The corresponding instruction is determined, and the motor is driven and controlled in the rotation direction of the determined instruction.

  According to this configuration, by alternately reading the instruction of the driving instruction means and the instruction of the direction instruction means, the period from the confirmation of the instruction by the driving instruction means to the confirmation of the instruction by the direction instruction means is shortened, and the operability is improved. Can be improved. Then, by confirming the instruction by the direction instructing unit after the instruction by the driving instruction unit is confirmed, the motor can be driven to rotate in the intended direction.

  ADVANTAGE OF THE INVENTION According to this invention, operability is good and it can provide the electric tool which can drive a motor to the direction which intends, and its control method.

(First embodiment)
Hereinafter, a first embodiment will be described with reference to FIGS.
As shown in FIG. 1, the electric power tool 1 of the present embodiment has a substantially bottomed cylindrical motor housing 2, and the motor 3 as a drive source has a rotating shaft 4 whose axis is the axis of the motor housing 2. It is accommodated in the motor housing 2 along the direction (left-right direction in the figure). A dome portion 5 that gradually decreases in diameter toward the front end 5a is attached to the opening end 2a of the motor housing 2, and the dome portion 5 has an axial direction (the left-right direction in the figure). An output shaft 6 is provided so as to follow. The output shaft 6 is connected to the rotating shaft 4 of the motor 3 via a torque amplifier 7 accommodated in the dome portion 5. A bit mounting portion 8 to which a tool (bit) (not shown) can be mounted is formed at the tip 6 a of the output shaft 6.

  A handle portion 9 extends in the vicinity of the opening end 2a of the motor housing 2 along a direction substantially orthogonal to the axial direction of the motor housing 2, and an operator operates and stops the electric tool 1 on the handle portion 9. An operation instruction switch (hereinafter referred to as trigger switch) 10 is provided as an operation instruction means for instructing. The trigger switch 10 has a main body portion 10a fixed in the handle portion 9, and an operation portion 10b whose tip protrudes from the front end of the handle portion 9 and is urged in the protruding direction from the main body portion 10a.

  A direction indicating switch 11 as a direction indicating means for the operator to indicate the rotation direction of the tool (bit), that is, the rotation direction of the motor 3, protrudes from the surface of the handle portion 9 slightly above the trigger switch 10. It is exposed in the form. The direction indicating switch 11 has an operation knob that penetrates the handle portion 9 in the left-right direction (front and back direction in the drawing), and indicates the rotation direction of the motor 3 by moving the operation knob in the left-right direction.

  A battery mounting portion 12 is formed at the lower end of the handle portion 9, and a battery 13 as a power source is mounted on the battery mounting portion. The handle portion 9 accommodates a control circuit 14 as control means for controlling the operation of the motor 3 that is a drive source based on the operation states of the trigger switch 10 and the direction indicating switch 11. The motor housing 2 houses a drive circuit 15 that is controlled by the control circuit 14 to generate and supply drive power to the motor 3.

  FIG. 3 is a block diagram illustrating a schematic electrical configuration of the electric power tool 1. In the electric tool 1 of the present embodiment, a brushless motor is employed as the motor 3. As the drive circuit 15, a known PWM inverter formed by connecting a plurality (six) of switching elements (FETs) 16 corresponding to the motor 3 is used.

  Specifically, the drive circuit 15 includes FETs 16a to 16f as switching elements. Each series circuit (arm) of FETs 16a, 16d, FETs 16b, 16e, and FETs 16c, 16f is connected in parallel. The lower FETs 16d, 16e, and 16f are connected to the negative terminal of the battery 13. The connection points 17u, 17v, 17w of the upper and lower stage FETs in each arm are connected to the motor coils 3u, 3v, 3w of the motor 3, respectively.

The gate terminals of the FETs 16 a to 16 f are connected to the control circuit 14. The control circuit 14 is connected to the trigger switch 10 and the direction indication switch 11.
As shown in FIG. 2A, the main body 10a (see FIG. 1) of the trigger switch 10 has fixed terminal plates 21a and 21b and a slider 22 that is moved by the operation unit 10b. Yes. When the slider 22 does not electrically connect the terminal plates 21a and 21b as indicated by a solid line, the main body 10a outputs a driving instruction signal of a predetermined level (for example, L level). By electrically connecting 21a and 21b, an operation instruction signal of a predetermined level (for example, H level) is output.

  As shown in FIG. 2B, the direction indicating switch 11 has a common terminal 23, switching terminals 24a and 24b arranged on both sides thereof, and a slider 25 that is moved by an operation knob. The direction indication switch 11 outputs a direction indication signal of a predetermined level (for example, H level) when the slider 25 electrically connects the common terminal 23 and one switching terminal 24a, and the slider 25 is common. When the terminal 23 and the other switching terminal 24b are electrically connected, a direction instruction signal of a predetermined level (for example, L level) is output.

  As shown in FIG. 3, the control circuit 14 samples the signals output from the switches 10 and 11, and determines the driving instruction and the rotation direction based on the signal levels. The control circuit 14 outputs a motor control signal (gate on / off signal) for controlling the operation and rotation direction of the motor 3 to the gate terminals of the FETs 16a to 16f in accordance with the determined instructions. Then, the FETs 16 a to 16 f are turned on / off in response to the motor control signal, whereby the DC voltage of the battery 13 is converted into three-phase driving power and supplied to the motor 3.

  That is, as shown in FIG. 1, the electric power tool 1 of this embodiment attaches an arbitrary bit (not shown) to the bit attachment portion 8 and grips the handle portion 9. Then, after setting the rotation direction of the bit by operating the direction indicating switch 11, the bit mounted on the bit mounting portion 8 is driven in the desired rotation direction by driving the motor 3 by operating the trigger switch 10. It can be rotated with an arbitrary torque.

  As shown in FIG. 3, a notification unit 18 is connected to the control circuit 14. The notification unit 18 includes light emitting means such as one or a plurality of LEDs. The control circuit 14 notifies the operator of the operating state of the electric power tool 1 via the notification unit 18.

Next, the operation of the control circuit 14 will be described according to the flowchart shown in FIG.
First, the control circuit 14 reads a driving instruction (step 31), and determines whether or not the driving instruction is driving (step 32). That is, the control circuit 14 reads a signal output from the trigger switch 10 and determines whether the driving instruction is driven or stopped based on the signal level. Then, the control circuit 14 proceeds to the next step when the driving instruction is driving, returns to step 31 when the driving instruction is not driving, and reads the driving instruction again. That is, the control circuit 14 waits until the driving instruction is driven.

  Next, the control circuit 14 reads the direction instruction (step 33), and determines the first driving / direction instruction (step 34). That is, the control circuit 14 reads a signal output from the direction indication switch 11 and determines a direction indication based on the signal level. In the present embodiment, the control circuit 14 determines that the rotation direction is normal rotation in response to the H level signal, and determines that the rotation direction is reverse rotation in response to the L level signal. The control circuit 14 stores each instruction determined at this time as the first instruction. Then, the control circuit 14 counts the number of times the driving instruction and the direction instruction are input, that is, the control circuit 14 sets “1” to the driving instruction number and the direction instruction number.

  Next, the control circuit 14 reads the driving instruction (step 35), and determines whether or not the driving instruction matches the first instruction (step 36). That is, the control circuit 14 determines whether or not the same operation instruction is continuously input. Then, the control circuit 14 proceeds to step 37 if they do not match. In step 37, each instruction count is cleared, that is, “0” is set in the operation instruction count and the direction instruction count, and the process returns to step 31.

  When the driving instruction coincides with the first instruction in step 36, the control circuit 14 counts up (+1) the number of driving instructions, reads the direction instruction (step 38), and the direction instruction becomes the first instruction. It is determined whether or not they match (step 39). That is, the control circuit 14 determines whether or not the same direction instruction is continuously input. Then, the control circuit 14 proceeds to step 37 if they do not match. In step 37, the fixed number is cleared, that is, "0" is set in the fixed number, and the process returns to step 31.

  When the direction instruction coincides with the first instruction in step 39, the control circuit 14 counts up (+1) the direction instruction number, and then determines whether or not the driving instruction has been matched four times. It is determined whether or not “4” (step 40). If they do not match four times, that is, if the number of driving instructions is less than “4”, the control circuit 14 returns to step 35.

  If the driving of the driving instruction matches four times in step 40, the control circuit 14 determines in step 41 whether the forward rotation of the direction instruction matches four times (step 41). When the forward rotation of the direction instruction coincides four times, the control circuit 14 performs on / off control of the FETs 16a to 16f to drive the motor 3 in the forward direction (step 42).

  If it is determined in step 41 that the forward rotation of the driving instruction does not match four times, the control circuit 14 determines whether the reverse rotation of the direction instruction matches four times (step 43). When the reverse of the direction instruction coincides four times, the control circuit 14 controls the FETs 16a to 16f to turn on and off to drive the motor 3 in the reverse direction (step 44).

  After starting the driving of the motor 3, the control circuit 14 reads the operation instruction and determines whether or not the operation instruction is stopped (step 45). When the operation instruction is stopped, the operation instruction number and the direction instruction number are determined. And the FETs 16 to 16 f shown in FIG. 3 are controlled to stop the motor 3.

  That is, when the driving instruction of the motor 3 is instructed by the driving instruction, the control circuit 14 alternately reads the driving instruction and the direction instruction and counts the number of instructions. Then, the control circuit 14 determines the operation instruction and the direction instruction when driving is continued four times and the same rotation direction instruction is continued four times, and drives the motor 3 in the determined rotation direction. On the other hand, when the instruction different from the first instruction is read during counting of the number of instructions, the control circuit 14 clears the number of instructions.

  Further, after driving the motor 3, the control circuit 14 masks the direction instruction, that is, does not accept the direction instruction until the operation instruction indicating the stop is indicated. As a result, as shown in FIG. 5, even if the direction indicating switch is operated (time t3) while the motor 3 is driven in the forward rotation (period t1-t1 ′), the control circuit 14 does not accept the instruction. The forward rotation drive for the motor 3 is continued. Similarly, even if the direction indicating switch is operated (time t4) while the motor 3 is being driven in reverse rotation (period t2-t2 ′), the control circuit 14 does not accept the instruction and continues the reverse rotation driving with respect to the motor 3. .

The operation of the control circuit 14 configured as described above will be described with reference to FIGS. In the figure, “◯” indicates the timing read by the control circuit 14.
As a first example, as shown in FIG. 6, after the direction instruction is switched from normal rotation to reverse rotation by the direction instruction switch 11, the driving instruction is driven by the trigger switch 10. The control circuit 14 determines that the direction instruction is reversed based on the L level signal after determining that the driving instruction is driven based on the H level signal. Then, the control circuit 14 stores these determination results as the first instruction. Then, the control circuit 14 alternately repeats the reading of the driving instruction and the reading of the direction instruction. Then, at time t11, the control circuit 14 drives the motor 3 in reverse since the second to fourth driving instructions coincide with the first instruction and the second to fourth direction instructions coincide with the first instruction. To do.

  As a second example, as shown in FIG. 7, the direction instruction is switched from forward rotation to reverse rotation by the direction instruction switch 11, and at the same time, the operation instruction is driven by the trigger switch 10. The control circuit 14 determines that the direction instruction is reversed based on the L level signal after determining that the driving instruction is driven based on the H level signal. Then, the control circuit 14 stores these determination results as the first instruction. Then, the control circuit 14 alternately repeats the reading of the driving instruction and the reading of the direction instruction. Then, at time t12, the control circuit 14 drives the motor 3 in reverse since the second to fourth driving instructions coincide with the first instruction and the second to fourth direction instructions coincide with the first instruction. To do.

  As a third example, as shown in FIG. 8, the direction indication is switched from normal rotation to reverse rotation by the direction indication switch 11, and at the same time, the driving indication is driven by the trigger switch 10 and then input from the direction indication switch 11. Change the signal. The change in the signal level occurs due to mechanical chattering of the switch 11, mixing of noise, intentional operation of the switch 11, and the like.

  The control circuit 14 determines that the direction instruction is reversed based on the L level signal after determining that the driving instruction is driven based on the H level signal. Then, the control circuit 14 stores these determination results as the first instruction. Next, the control circuit 14 determines that the driving instruction is driven based on the H level signal. Since this instruction matches the first driving instruction, the direction instruction is read. At this time, the control circuit 14 determines that the direction instruction is normal rotation based on the L level signal. Since this instruction does not coincide with the first instruction, the operation instruction number and the direction instruction number are cleared. Next, the control circuit 14 determines that the driving instruction is driven based on the H level signal, and then determines that the direction instruction is reverse rotation based on the L level signal. Then, the control circuit 14 stores these determination results as the first instruction. Then, at time t13, the control circuit 14 drives the motor 3 in reverse since the second to fourth driving instructions coincide with the first instruction and the second to fourth direction instructions coincide with the first instruction. To do.

  As a fourth example, as shown in FIG. 9, the direction indication is switched from normal rotation to reverse rotation by the direction indication switch 11, and at the same time, the operation instruction is driven by the trigger switch 10 and then input from the trigger switch 10. The signal changes. The change in the signal level occurs due to mechanical chattering of the switch 11, mixing of noise, intentional operation of the switch 11, and the like.

  The control circuit 14 determines that the direction instruction is reversed based on the L level signal after determining that the driving instruction is driven based on the H level signal. Then, the control circuit 14 stores these determination results as the first instruction. Next, the control circuit 14 determines that the driving instruction is stopped by an L level signal, and since this instruction does not coincide with the first driving instruction, the driving instruction number and the direction instruction number are cleared. Next, the control circuit 14 determines that the driving instruction is driven based on the H level signal, determines that the direction instruction is reverse based on the L level signal, and stores these determination results as the first instruction. At time t14, the control circuit 14 drives the motor 3 in reverse since the second to fourth driving instructions match the first instruction and the second to fourth direction instructions match the first instruction. To do.

As described above, according to the present embodiment, the following effects can be obtained.
(1) At the start of driving of the electric power tool 1, the control circuit 14 alternately reads an operation instruction by a signal output from the trigger switch 10 and a direction instruction by a signal output from the direction instruction switch 11, 2-4 When the first driving instruction matches the first instruction, the driving instruction is confirmed, and when the second to fourth direction instructions coincide with the first instruction, the driving instruction is confirmed, and the motor 3 moves in the determined direction. To drive. That is, the control circuit 14 determines the direction instruction after determining the driving instruction. Accordingly, the tool can be rotated by driving the motor 3 in the direction intended by the operator by the direction indicating switch 11.

  (2) After the driving instruction by the signal output from the trigger switch 10 is driven, the control circuit 14 counts the number of instructions read in the instruction, and when the read instruction is different from the first instruction The instruction count was cleared. Therefore, even after the driving instruction becomes driving, even if the direction instruction by the direction indicating switch 11 changes until the instruction is determined, each instruction is determined after the same instruction continues four times after the change. Therefore, it is possible to prevent the tool from being rotated by driving the motor 3 in the direction intended by the operator by the direction indicating switch 11 and driving the motor 3 in the direction not intended by the operator.

  (3) The control circuit 14 alternately reads the operation instruction based on the signal output from the trigger switch 10 and the direction instruction based on the signal output from the direction instruction switch 11. When the trigger switch 10 is operated after the direction indicating switch 11 is operated, the driving instruction indicating driving is continuously read four times, the driving instruction is determined by the trigger switch 10, and is read next to the driving instruction read for the fourth time. The direction instruction is determined by the direction instruction read after the timing when the driving instruction is read by the direction instruction. Therefore, the driving method according to the present embodiment has a longer time from when the trigger switch 10 is operated to when the motor 3 is driven than when the direction is determined by reading a plurality of direction instructions after the driving instruction is determined. The operating feeling of the electric power tool 1 can be made short and good.

  (4) The control circuit 14 is configured not to accept the direction instruction from the direction instruction switch 11 after the driving of the motor 3 is started. For this reason, it is possible to prevent the rotation direction of the motor 3 from being changed by mixing noise or unintentional operation of the direction indicating switch 11 after the motor 3 is driven.

(Second Embodiment)
Hereinafter, the second embodiment will be described with reference to FIGS.
The electric power tool of this embodiment can control the rotation speed of the motor 3 shown in FIG. For this control, the trigger switch 10 has a speed setting unit 10c as speed setting means shown in FIG. The speed setting unit 10c is provided in the main body 10a shown in FIG. The speed setting unit 10 c includes a fixed terminal 51, a variable terminal 52, and a slider 53. The fixed terminal 51 is made of a metal such as copper, and the variable terminal 52 has a resistor 52a and a terminal portion 52b. The slider 53 is moved by the operation unit 10b, and the contact position between the slider 53 and the variable terminal 52 changes according to the movement. The slider 53 electrically connects the resistor 52 a or the terminal portion 52 b and the fixed terminal 51. With this configuration, the speed setting unit 10 c changes the resistance value between the fixed terminal 51 and the terminal unit 52 b according to the contact position of the slider 53. That is, the speed setting unit 10c constitutes a variable resistor, and a voltage dividing circuit in which the variable resistor and a fixed resistor (not shown) are connected in series is configured, and the speed setting unit 10c corresponds to the operation position of the operation unit 10b of the trigger switch 10. The voltage is input to the control circuit 14 shown in FIG.

  The control circuit 14 samples the voltage input from the speed setting unit 10c at a predetermined timing, and calculates an average value of a plurality of (for example, four) sampling values. Then, the control circuit 14 supplies a pulse signal having a duty proportional to the average value to the gate terminals of the FETs 16a to 16f, and performs PWM control on the FETs 16a to 16f. The number of sampling values for calculating the average value may be changed as appropriate. Moreover, you may make it calculate an average value except a predetermined value like a maximum value or a minimum value among several sampling values.

  As shown in FIG. 11, the control circuit 14 determines that the rotation direction is reversed based on the signal level input according to the operation of the direction indicating switch 11, and when the driving instruction is driven by the operation of the trigger switch 10, the speed setting is performed. When the voltage (average value) input from the unit 10c exceeds a predetermined threshold voltage Vth, the motor 3 is driven at a rotational speed corresponding to the voltage (average value).

  Further, after driving the motor 3, the control circuit 14 masks the direction instruction, that is, does not accept the direction instruction until the operation instruction indicating the stop is indicated. As a result, as shown in FIG. 5, even if the direction indicating switch is operated (time t3) while the motor 3 is driven in the forward rotation (period t1-t1 ′), the control circuit 14 does not accept the instruction. The forward rotation drive for the motor 3 is continued. Similarly, even if the direction indicating switch is operated (time t4) while the motor 3 is being driven in reverse rotation (period t2-t2 ′), the control circuit 14 does not accept the instruction and continues the reverse rotation driving with respect to the motor 3. .

  As shown in FIG. 5, even in the electric tool that can change the rotation speed of the motor 3, that is, the rotation speed of the tool, as in the first embodiment, the same instruction (drive) is repeated a plurality of times. After the operation instruction is confirmed, when the same instruction continues for a plurality of directions, the direction instruction is confirmed and the motor 3 is driven to prevent the motor 3, that is, the tool from rotating in an unintended direction. To do.

As described above, according to the present embodiment, the following effects can be obtained.
(1) As described above, even in the electric tool capable of changing the rotation speed of the motor 3, that is, the rotation speed of the tool, the same effect as that of the first embodiment can be obtained.

  (2) The trigger switch 10 is configured to output an operation instruction by the slider 22 shown in FIG. 2A, a law shown in FIG. 10, and a rotation speed instruction by the setting unit 10c. Therefore, as shown in FIG. 11, even when one of the two instructions (signals) fluctuates due to noise or the like, malfunction due to the fluctuation can be prevented.

In addition, you may implement each said embodiment in the following aspects.
In addition, you may change this embodiment as follows.
In the above embodiment, a brushless motor is adopted as the motor 3, but the motor 3 may be embodied in a configuration using a brushed motor. Even with such a configuration, the same effects as in the present embodiment can be obtained except for those related to the adoption of the brushless motor.

  In the above embodiment, a three-phase plusless motor is used as the motor 3, but other brushless motors may be used. For example, a DC motor may be used as shown in FIG. In this case, the four FETs 16 and the motor 3 constituting the drive circuit 15 constitute a so-called H bridge circuit.

In the above embodiment, the driving instruction is determined when the driving of the driving instruction is continued four times. However, the driving instruction may be fixed when the driving instruction is continued three times or less or five times or more.
In the above embodiment, the direction instruction is determined when the same direction instruction is continued four times. However, the direction instruction may be determined when the direction instruction is continued three times or less, or five times or more.

The fragmentary sectional view of an electric tool. (A) (b) is a schematic block diagram of a switch. The block diagram which shows the electric constitution of an electric tool. The flowchart which shows operation | movement of a control part. The wave form diagram which shows operation | movement of an electric tool. The wave form diagram which shows operation | movement of an electric tool. The wave form diagram which shows operation | movement of an electric tool. The wave form diagram which shows operation | movement of an electric tool. The wave form diagram which shows operation | movement of an electric tool. The schematic block diagram of another switch. The wave form diagram which shows operation | movement of an electric tool. The wave form diagram which shows operation | movement of an electric tool. The block diagram which shows another electric constitution.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 3 ... Motor, 10 ... Operation instruction switch, 11 ... Direction instruction switch, 14 ... Control circuit.

Claims (6)

An electric tool powered by a motor capable of normal rotation and reverse rotation,
Direction indicating means for indicating the rotation direction of the motor;
Driving instruction means for alternatively instructing driving / stopping of the motor;
When the instructions of the driving instruction means and the instructions of the direction instructing means are alternately read and the instructions of the driving instruction means read a plurality of times match, the matching instructions are fixed, and then the direction instructions read a plurality of times Control means for determining the matching instruction when the instructions of the means match, and driving the motor in the rotation direction of the determined instruction;
A power tool characterized by comprising: The control means includes
A first step of reading instructions of the direction indicating means when a driving instruction is read from the driving instruction means, and storing each instruction as a first instruction;
Next, it is determined whether or not the instruction read from the driving instruction means matches the first instruction, and when the read instruction matches the first instruction, the instruction of the direction instruction means is read. Determining whether or not the read instruction matches the first instruction, and when the read instruction matches the first instruction, a second step proceeds;
Have
A third step of driving the motor in the direction instructed by the direction indicating means after performing the second step at least once;
The power tool according to claim 1, comprising:   The control means counts up the number of instructions when the read instruction matches the first instruction in the second step, and when the instruction number matches a predetermined value in the third step. The power tool according to claim 2, wherein each instruction is confirmed.   In the second step, when the instruction read from the driving instruction means does not coincide with the first instruction, or when the instruction read from the direction instruction means does not coincide with the first instruction, The power tool according to claim 3, wherein the number of instructions is cleared.   The power tool according to claim 1, wherein the control unit does not receive an instruction from the direction instruction unit after driving the motor. A method for controlling an electric tool powered by a motor capable of normal rotation and reverse rotation,
Direction indicating means for indicating the rotation direction of the motor;
Driving instruction means for alternatively instructing driving / stopping of the motor;
Control means for driving and controlling the motor according to an instruction from the driving instruction means and an instruction from the direction instruction means;
Have
The control means includes
When the instructions of the driving instruction means and the instructions of the direction instructing means are alternately read and the instructions of the driving instruction means read a plurality of times match, the matching instructions are fixed, and then the direction instructions read a plurality of times If the instructions of the means match, confirm the matching instructions and drive control the motor in the direction of rotation of the confirmed instructions;
A control method for an electric tool characterized by the above.

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