JP2015080896A - Electric tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric tool capable of easily pulling out even if a rotary blade such as a saw blade bites into a work material. A control unit 27 has a forward / reverse switchable state in which forward rotation and reverse rotation of a brushless motor 9 can be switched, and a reverse rotation prohibition state in which reverse rotation of the brushless motor 9 is not allowed. When the control unit 27 detects that the brushless motor 9 is locked, the control unit 27 stops the brushless motor 9 and is in a forward / reverse switchable state. When the main trigger switch 18 is turned on to reverse the brushless motor 9 in the reverse rotation mode, the control unit 27 reverses, for example, reverses for a short time and stops, or reverses the saw blade 8 from half a rotation to one rotation. And make it stop. [Selection diagram] FIG. 8

Description

  The present invention relates to an electric tool such as an electric circular saw for cutting a work material such as wood.

  An electric circular saw generally has a structure in which a main body with a built-in motor is connected to an upper portion of a base, and a saw blade that is rotationally driven by the motor is protruded from the bottom surface of the base by a predetermined amount. The set work material is cut with the saw blade (Patent Document 1 below).

JP 2012-213829 A

  In particular, in the case of an electric circular saw or tabletop circular saw using a saw blade 8 having a carbide tip 8a at the cutting edge, as shown in FIG. 13, the saw blade 8 bites into the work material during cutting and the motor locks. May not be able to rotate. Then, it becomes difficult to extract the saw blade 8 from the work material, and there is a possibility that the cutting surface of the work material may be damaged or the saw blade 8 may be deformed or damaged if it is forcibly extracted. It was. Further, when the bite is large, it takes time to extract the saw blade from the work material, and there is a problem that work efficiency is deteriorated.

  The present invention has been made in view of such a situation, and an object of the present invention is to provide an electric tool that can be easily extracted even when a rotary blade such as a saw blade bites into a work material.

  One embodiment of the present invention is a power tool. The electric tool includes a motor, a rotary blade that is rotated by the motor, and a control unit that controls the motor, and the control unit is capable of forward / reverse switching capable of switching between normal rotation and reverse rotation of the motor. Have

  The control unit may detect the lock of the motor as a condition necessary for the forward / reverse switchable state.

  The control unit may be in a reverse rotation prohibition state in which the motor is prohibited from reverse rotation when the motor is caused to perform a predetermined reverse rotation operation in the forward / reverse switchable state.

  The controller may perform a predetermined reverse operation when the motor is reversely rotated.

  The predetermined reversing operation may be an operation of reversing and stopping for a predetermined time.

  The predetermined reversing operation may be an operation of reversing and stopping so that the rotary blade rotates from half rotation to one rotation.

  In the predetermined reverse rotation operation, electric power may be supplied to the motor with a duty within a range of 30 to 70%.

  A manual switch for switching the motor to reverse rotation may be provided.

  You may provide the alerting | reporting means which alert | reports the direction in which the said control part rotates the said motor outside.

  Another aspect of the present invention is a power tool. The electric tool includes a motor, a rotary blade rotated by the motor, and a control unit that controls the motor, and the control unit enters a reverse rotation mode when detecting the lock of the motor.

  It should be noted that any combination of the above-described constituent elements, and those obtained by converting the expression of the present invention between methods and systems are also effective as aspects of the present invention.

  ADVANTAGE OF THE INVENTION According to this invention, even if rotary blades, such as a saw blade, bite into a work material, the electric tool which can be extracted easily can be provided.

The top view of the electric circular saw which concerns on embodiment of this invention. The same side view. The rear view. The front view. The 1st top view which made the section of the electric circular saw a part. The 2nd top view. AA sectional drawing of FIG. The functional block diagram of the electric circular saw shown in FIG. FIG. 9 is a first flowchart of control by the control unit 27 shown in FIG. 8. FIG. 9 is a second flowchart of control by the control unit 27 shown in FIG. 8. FIG. 9 is a third flowchart of control by the control unit 27 shown in FIG. 8. The exemplary timing chart of operation of the electric circular saw of an embodiment. Explanatory drawing of the state where the saw blade of the electric circular saw bites into the work material.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In addition, the same code | symbol is attached | subjected to the same or equivalent component, member, process, etc. which are shown by each drawing, and the overlapping description is abbreviate | omitted suitably. In addition, the embodiments do not limit the invention but are exemplifications, and all features and combinations thereof described in the embodiments are not necessarily essential to the invention.

  1 is a plan view of an electric circular saw according to an embodiment of the present invention, FIG. 2 is a side view thereof, FIG. 3 is a rear view thereof, and FIG. 4 is a front view thereof. FIG. 5 is a first plan view, partly in section, of the electric circular saw of FIG. FIG. 6 is a second plan view of the same. 7 is a cross-sectional view taken along the line AA in FIG.

  The electric circular saw (cordless circular saw) of this embodiment includes a base 1 and a main body 2. The base 1 is a substantially rectangular plate made of metal such as aluminum. The longitudinal direction of the base 1 coincides with the cutting direction. The bottom surface of the base 1 is a sliding surface with the work material. As will be described later, the main body 2 is connected to the base 1 at two places in the front and rear, and is rotatable with respect to the base 1 and tilted to the left and right. The main body 2 includes a motor housing 3, a handle portion 4, a gear cover 5, a saw cover 6, a protective cover 7, and a saw blade 8 (rotating tool). The motor housing 3 is made of resin, for example, and incorporates a brushless motor 9 (FIGS. 5 and 6). The brushless motor 9 rotates the saw blade 8. The handle portion 4 is made of the same material as the motor housing 3 and extends in the front-rear direction above the motor housing 3. The handle portion 4 is provided with a main trigger switch 18 (main switch) as an operation portion for switching the driving and stopping of the brushless motor 9 by the user. As shown in FIGS. 3 and 4, the handle portion 4 is composed of a left part integrally provided with the motor housing 3 and a right part sandwiched between the motor housing 3 and the gear cover 5. A battery pack mounting portion 4a, which will be described later, is configured by a combination of the component and the right-side component, and a control circuit board storage portion 4b, which will be described later, is provided on the right-side component of the handle portion 4 located on the saw blade 8 side. Note that the boundary between the left part and the right part of the handle part 4 is a line appearing at the center of the handle part 4 in FIGS. 1, 3, 4, and the like.

  A battery pack attachment portion 4a (battery attachment portion) and a control circuit board storage portion 4b are integrally provided at the lower rear end of the handle portion 4. The battery pack 20 (storage battery) is detachably mounted on the battery pack mounting portion 4a by sliding it from the rear. A forward / reverse selector switch 16 (for example, a tact switch) and a forward / reverse display LED 29 are provided below the handle portion 4 and on the upper surface of the battery pack mounting portion 4a. The user can switch the brushless motor 9 to reverse rotation when the lock of the brushless motor 9 is detected by the forward / reverse selector switch 16. When the brushless motor 9 is switched to reverse rotation, the forward / reverse display LED 29 is lit, for example, to notify the outside. The battery pack 20 supplies driving power to the brushless motor 9. As shown in FIG. 1, the left side surface of the battery pack 20 attached to the battery pack mounting portion 4 a and the left side surface of the motor housing 3 are on substantially the same plane. That is, the distance from the saw blade 8 to the left side surface of the motor housing 3 and the distance from the saw blade 8 to the left side surface of the battery pack 20 are substantially the same, with the left side surface of the battery pack 20 and the left side surface of the motor housing 3 facing down. Thus, the electric circular saw can be placed, and the saw blade 8 can be easily replaced. The control circuit board storage portion 4 b is provided on the right side of the battery pack 20. The control circuit board 21 is housed and held in the control circuit board housing portion 4b. The control circuit board 21 is equipped with a control unit (controller) that controls the operation of the brushless motor 9. The control circuit board 21 is substantially perpendicular to the rotation axis of the brushless motor 9 (rotation axis of the saw blade 8). The left side of the control circuit board 21, that is, the control circuit board 21 and the battery pack 20, is partitioned by a controller cover 22 made of, for example, resin.

  The gear cover 5 is provided on the right side of the handle portion 4. The gear cover 5 is made of metal, for example, and incorporates a rotation transmission mechanism between the brushless motor 9 and the saw blade 8. The rotation transmission mechanism includes a known speed reduction mechanism. The saw cover 6 is attached to the gear cover 5 and covers the upper half of the saw blade 8 together with the gear cover 5. The saw cover 6 may be formed of the same material as the gear cover 5 and integrally. The front end portions of the gear cover 5 and the saw cover 6 are rotatably connected by a rotation support portion 14. The protective cover 7 is made of resin, for example, and is provided on the rear side of the gear cover 5 so as to be rotatable along the outer edges of the gear cover 5 and the saw cover 6. A spring (not shown) is interposed between the gear cover 5 and the protective cover 7. This spring urges the protective cover 7 against the gear cover 5 in the circumferential direction of the gear cover 5 and the saw cover 6 and in the direction covering the lower half of the saw blade 8 (counterclockwise in FIG. 2). Therefore, in a state where the cutting operation is not performed, the protective cover 7 covers the lower half of the saw blade 8 (the portion protruding downward from the bottom surface of the base 1) except for the front part.

  A bevel plate 12 is erected in front of the base 1. The bevel plate 12 stands upright in a short direction substantially orthogonal to the cutting direction. The bevel plate 12 is provided with a long hole 13. The long hole 13 has an arc shape centered on the first tilting shaft portion 15a extending in the cutting direction and orthogonal to the first tilting shaft portion 15a. The rotation support portion 14 is supported so as to be tiltable to the left and right with respect to the base 1 with the first tilt shaft portion 15a as a center. The tilting position of the rotation support unit 14 is adjusted with the tilt angle adjustment lever 11 loosened, and is fixed by tightening the tilt angle adjustment lever 11. The rotation support unit 14 rotatably supports the front end portion of the saw cover 6 with an axis parallel to the rotation axis of the brushless motor 9 (the rotation axis of the saw blade 8). Adjustment and fixing of the rotational position of the saw cover 6 will be described later.

  A link 10 is provided behind the base 1 so as to be rotatable about a tilting shaft portion 15b coaxial with the first tilting shaft portion 15a, and extends along the left side surface of the gear cover 5. The link 10 is made of a metal such as aluminum. In a state where the cutting depth adjusting lever 19 is loosened, the link 10 and the gear cover 5 can slide relative to each other, and the rotational position of the saw cover 6 relative to the base 1, that is, the cutting depth can be adjusted. And the rotation position of the gear cover 5 can be fixed by tightening the cutting depth adjusting lever 19.

  As shown in FIG. 6, the brushless motor 9 has a rotor core 9b around the output shaft 9a. The output shaft 9 a is parallel to the rotation axis of the saw blade 8. The rotor core 9b rotates integrally with the output shaft 9a. A rotor magnet 9c is inserted and supported in the rotor core 9b. The stator core 9d is provided so as to surround the outer peripheral surface of the rotor core 9b. The stator core 9d is provided with a stator coil 9f with an insulator 9e interposed therebetween. A switching substrate 23 is fixed to the left end side of the stator core 9d. The switching substrate 23 is substantially perpendicular to the output shaft 9a. As shown in FIG. 7, six switching elements 23 a (such as FETs) are mounted on the switching substrate 23 in a state where the main body portion is tilted. The switching element 23 a switches the supply voltage from the battery pack 20. As shown in FIG. 5, the terminal portion 20 a of the battery pack 20 and the switching substrate 23 are electrically connected to each other by a wiring 24. The wiring 25 electrically connects the terminal portion 20a of the battery pack 20 and the control circuit board 21 to each other. The wiring 26 electrically connects the control circuit board 21 and the switching board 23 to each other. A control signal from the controller of the control circuit board 21 is applied to the control terminal (gate) of the switching element 23a on the switching board 23 through the wiring 26, and the on / off of the switching element 23a is controlled. A cooling fan 33 is attached to the output shaft 9a of the brushless motor 9 and rotates together with the output shaft 9a. The brushless motor 9 and the switching element 23a are cooled by the airflow generated by the cooling fan 33.

  FIG. 8 is a functional block diagram of the electric circular saw according to the embodiment of the present invention. The control unit 27 is mounted on the control circuit board 21 shown in FIG. The control unit 27 performs various controls such as drive control of the inverter unit 28 and lighting control of the forward / reverse display LED 29. The inverter unit 28 is a circuit in which the switching elements 23a (six in this case) shown in FIGS. 6 and 7 are bridge-connected. The forward / reverse display LED 29 notifies the user of the rotation mode (forward rotation mode or reverse rotation mode) of the control unit 27, that is, the direction (forward rotation or reverse rotation) in which the brushless motor 9 rotates when the main trigger switch 18 is turned on. For example, the lighting means indicates a reverse rotation mode, and the extinction indicates a normal rotation mode. Further, the forward / reverse display LED 29 may blink in a forward / reverse switching enabled state (light emission in a mode different from forward rotation and reverse rotation). The detection resistor 32 is provided in the drive current path of the brushless motor 9. The control circuit voltage supply circuit 41 converts the voltage of the battery pack 20 into a voltage suitable for the operation of the control unit 27 and supplies the converted voltage to the control unit 27. The magnetic sensor 42 is a Hall element, for example, and outputs a signal corresponding to the rotational position of the brushless motor 9.

  In the control unit 27, the motor current detection circuit 37 detects the drive current of the brushless motor 9 based on the terminal voltage of the detection resistor 32. The switch operation detection circuit 38 detects the operation of the main trigger switch 18 by the user. The applied voltage setting circuit 39 sets the duty of the PWM signal (hereinafter also simply referred to as “duty”) to be applied to each switching element 23 a of the inverter unit 28 according to the operation amount of the main trigger switch 18. The rotor position detection circuit 35 detects the rotation position of the brushless motor 9 based on a signal from the magnetic sensor 42. The motor rotation speed detection circuit 36 detects the rotation speed of the brushless motor 9 based on the signal from the rotor position detection circuit 35. The calculation unit 34 drives the control signal output circuit 40 according to the duty set by the applied voltage setting circuit 39 and the rotational position of the brushless motor 9 detected by the rotor position detection circuit 35, and each of the inverter units 28. Switching control of the switching element 23a is performed. Further, the calculation unit 34 calculates the rotation speed of the brushless motor 9 based on the detection result of the rotor position detection circuit 35. Further, the rotational speed of the saw blade 8 can be detected from the detection result of the rotor position detection circuit 35 based on the set reduction ratio of the brushless motor 9 and the saw blade 8.

  The control unit 27 has a forward / reverse switchable state in which the brushless motor 9 can be switched between forward rotation and reverse rotation, and a reverse rotation prohibition state in which the brushless motor 9 is not allowed to reverse. In other words, in the forward / reverse switching enabled state, the control unit 27 effectively accepts the operation of the forward / reverse selector switch 16 by the user, for example, every time the user operates the forward / reverse selector switch 16, the forward rotation mode and the reverse rotation mode are set. Switch between. On the other hand, in the reverse rotation prohibition state, the control unit 27 maintains the rotation direction of the brushless motor 9 in the normal rotation (not switched to the reverse rotation) even if the user operates the forward / reverse switch 16. The control unit 27 is in the reverse rotation prohibited state in the initial state and the normal state, and when the lock of the brushless motor 9 is detected, the forward / reverse switching state is enabled.

  FIG. 9 is a first flowchart of control by the control unit 27 shown in FIG. When the user turns on the main trigger switch 18 (S1, YES), the control unit 27 checks the lock flag (S2). The lock flag is “0” in the initial state and normal time, and is “1” when the lock of the brushless motor 9 is detected. If the lock flag is “0” (S2, YES), the control unit 27 checks whether the rotation mode is the forward rotation mode or the reverse rotation mode (S3). The forward rotation mode is a mode in which the brushless motor 9 is rotated forward when the main trigger switch 18 is turned on, and the reverse rotation mode is a mode in which the brushless motor 9 is reversed when the main trigger switch 18 is turned on. The control unit 27 is in the normal rotation mode in the initial state and normal time, and enters the reverse rotation mode when the forward / reverse switching switch 16 is operated in the forward / reverse switchable state.

  If the forward rotation mode is selected (S3, YES), the control unit 27 enters the reverse rotation prohibited state or maintains the reverse rotation prohibited state (S4), and causes the brushless motor 9 to rotate forward (S5). If the brushless motor 9 is not locked (S6, NO), the control unit 27 continues the forward rotation of the brushless motor 9 until the main trigger switch 18 is turned off. When detecting the lock of the brushless motor 9 (S6, YES), the control unit 27 stops the brushless motor 9 (S7), sets the lock flag to “1” (S8), and enters the forward / reverse switchable state (S8). S9). The lock of the brushless motor 9 can be detected, for example, by monitoring the drive current or the rotational speed of the brushless motor 9.

  If the lock flag is “1”, the controller 27 does not drive the brushless motor 9 even if the main trigger switch 18 is on (S2, NO). When the main trigger switch 18 is turned off (S1, NO), the control unit 27 stops the brushless motor 9 or maintains the stop of the brushless motor 9 (S10), and sets the lock flag to “0” (S11). . If it is reverse rotation mode in step S3 (S3, NO), the control part 27 will reverse the brushless motor 9 (S12). The control unit 27 continues the reverse rotation of the brushless motor 9 until the main trigger switch 18 is turned off.

  Note that the control unit 27 may perform a predetermined reverse operation as described later with reference to FIG. 10 or FIG. 11 when the main trigger switch 18 is turned on and the brushless motor 9 is reversely rotated in the reverse rotation mode. The predetermined reversing operation is, for example, an operation of reversing and stopping for a predetermined time (short time) or an operation of reversing and stopping so that the saw blade 8 is rotated from half rotation to one rotation.

  FIG. 10 is a second flowchart of the control by the control unit 27 shown in FIG. In this flowchart, when the brushless motor 9 is reversely rotated, the control unit 27 reverses the brushless motor 9 for a short time (for example, 30 milliseconds) (S13) and then stops (S14). The reverse rotation time of the brushless motor 9 does not depend on the operation time of the main trigger switch 18. Moreover, it is preferable to set the duty at the time of reverse rotation to a low duty within a range of 30 to 70%, and particularly within a range of 30 to 50%. Other points in the flowchart of FIG. 10 are the same as those shown in FIG.

  FIG. 11 is a third flowchart of the control by the control unit 27 shown in FIG. In the flowchart of FIG. 10, the reverse rotation of the brushless motor 9 is controlled by time, whereas in the flowchart of FIG. 11, the reverse rotation of the brushless motor 9 is controlled by angle. That is, in this flowchart, when the brushless motor 9 is reversely rotated, the control unit 27 reverses the brushless motor 9 by a predetermined angle (for example, 720 °) (S13 ′) and then stops (S14). The predetermined angle is set in advance in consideration of the reduction ratio so that the saw blade 8 rotates from half rotation to one rotation. The reverse rotation time of the brushless motor 9 does not depend on the operation time of the main trigger switch 18. Moreover, it is preferable to set the duty at the time of reverse rotation to a low duty within a range of 30 to 70%, and particularly within a range of 30 to 50%. Other points in the flowchart of FIG. 11 are the same as those shown in FIG. At the time of reverse rotation, if the duty is too high, the saw blade 8 starts to rotate rapidly at the moment when the saw blade 8 comes off the work material, the reaction is large and the workability is not good, and if the duty is too low, the saw blade Since there is a possibility that the torque at the time of reverse rotation 8 is insufficient and the saw blade 8 cannot be pulled out from the work material, as described above, the duty at the time of reverse rotation is, for example, in the range of 30 to 70%, particularly 30. It is preferable to set a low duty in the range of ˜50%. Further, in step 13 ′ in FIG. 11, the brushless motor 9 is reversed by a predetermined angle, but the rotation angle of the saw blade 8 is calculated from the detection result of the rotor position detection circuit 35, and the set saw blade 8 It can be reversed by a rotation angle (for example, an angle within one rotation).

  In the flowcharts of FIGS. 10 and 11, the control unit 27 may automatically enter the normal rotation mode and enter the reverse rotation prohibition state after the brushless motor 9 is rotated in the reverse direction and stopped (after S <b> 14).

  FIG. 12 is an exemplary timing chart of the operation of the electric circular saw according to the embodiment. This timing chart is an example when the lock of the brushless motor 9 is detected during the cutting of the wood, the wood is cut again after the brushless motor 9 is reversed. In the initial state, the main trigger switch 18 is off, the control unit 27 is in the forward rotation mode and the reverse rotation prohibited state, the forward / reverse selector switch 16 is off, and the lock flag is “0”. When the user turns on the main trigger switch 18 at time t1, the control unit 27 starts driving the brushless motor 9. When the driving current of the brushless motor 9 reaches a predetermined value at time t2, the control unit 27 detects the lock of the brushless motor 9, stops the brushless motor 9, sets the lock flag to “1”, and switches between forward and reverse. It becomes possible. When the user turns off the main trigger switch 18 at time t3, the control unit 27 sets the lock flag to “0”. When the user presses the forward / reverse selector switch 16 at time t4, the control unit 27 enters the reverse rotation mode. When the user turns on the main trigger switch 18 at time t5, the control unit 27 reverses the brushless motor 9, and stops the brushless motor 9 at time t6 when a predetermined time has elapsed or rotated by a predetermined angle. When the user presses the forward / reverse selector switch 16 at time t7, the control unit 27 returns to the forward rotation mode. When the user turns on the main trigger switch 18 at time t8, the control unit 27 starts driving the brushless motor 9, and when the user turns off the main trigger switch 18 at time t9, the control unit 27 stops the brushless motor 9.

  According to the present embodiment, the following effects can be achieved.

(1) Since the brushless motor 9 can be reversed, even if the saw blade 8 bites into the work material, the saw blade 8 can be easily extracted by reversing the brushless motor 9. For this reason, it is possible to reduce the risk of the saw blade 8 being forcibly extracted from the work material, the cut surface of the work material being scratched, or the saw blade 8 being deformed or damaged. Further, it is possible to solve the problem that it takes a long time to extract the saw blade 8 from the work material and the working efficiency is deteriorated.

(2) According to the control explained in FIG. 10 and FIG. 11, automatic reverse rotation operation (preferable reverse rotation time or reverse rotation angle and reverse rotation operation by duty) suitable for extracting the saw blade 8 that has bitten into the work material is automatically performed. The saw blade 8 can be removed more easily.

(3) Since the control unit 27 sets the detection of the lock of the brushless motor 9 as a necessary condition for the forward / reverse switchable state, the control unit 27 can prevent the brushless motor 9 from rotating inadvertently at normal times, and is easy to use. .

(4) Since the forward / reverse display LED 29 informs the rotation direction of the brushless motor 9 to the outside, it is convenient for the user to know the rotation direction of the brushless motor 9 before turning on the main trigger switch 18.

  The present invention has been described above by taking the embodiment as an example. However, it is understood by those skilled in the art that various modifications can be made to each component and each processing process of the embodiment within the scope of the claims. By the way. Hereinafter, modifications will be described.

  The electric circular saw is not limited to the cordless type described in the embodiment, and may be a type connected to an external AC power source. The motor serving as the drive source is not limited to the brushless motor illustrated in the embodiment, and may be a motor with a brush. The notification means is not limited to light (light emitting means) that performs notification by light (lighting, blinking, extinguishing, etc.) like the forward / reverse display LED 29, and may be, for example, a speaker (sound generation means) that performs sound notification. Good. After detecting that the brushless motor 9 is locked, the control unit 27 may wait for the main trigger switch 18 to turn off before entering the forward / reverse switchable state. When the controller 27 detects the lock of the brushless motor 9, the controller 27 may automatically enter the reverse rotation mode. In addition, after the brushless motor 9 performs a predetermined reverse rotation operation in the reverse rotation mode, the control unit 27 automatically returns to the normal rotation mode. May be. The controller 27 may be configured to enter the reverse rotation mode without detecting the lock of the brushless motor 9. The electric power tool is not limited to the electric circular saw described in the embodiment, and may be a tabletop circular saw, a planer, or a grounder as long as it uses a rotary blade with a limited rotation direction during work. It is effective for an electric circular saw or a table-top circular saw using a saw blade having a cemented carbide tip at the cutting edge.

DESCRIPTION OF SYMBOLS 1 Base, 2 Main body, 3 Motor housing, 4 Handle part, 4a Battery pack mounting part, 4b Control circuit board storage part, 5 Gear cover, 6 Saw cover, 7 Protective cover, 8 Saw blade, 9 Brushless motor, 9a Output shaft, 9b Rotor core, 9c Rotor magnet, 9d Stator core, 9e Insulator, 9f Stator coil, 10 link, 11 Inclination angle adjustment lever, 12 Bevel plate, 13 Long hole, 14 Rotation support part, 15a Tilt shaft part, 15b Tilt shaft part, 16 Forward / reverse selector switch, 18 main trigger switch, 19 cutting depth adjustment lever, 20 battery pack, 20a terminal, 21 control circuit board, 22 controller cover, 23 switching board, 23a switching element, 24-26 wiring, 27 control section , 28 in 29, forward / reverse display LED, 32 detection resistor, 33 cooling fan, 34 arithmetic unit, 35 rotor position detection circuit, 36 motor rotation speed detection circuit, 37 motor current detection circuit, 38 switch operation detection circuit, 39 application Voltage setting circuit, 40 control signal output circuit, 41 control circuit voltage supply circuit, 42 magnetic sensor

Claims (10)

  An electric tool comprising a motor, a rotary blade rotated by the motor, and a control unit for controlling the motor, wherein the control unit has a forward / reverse switchable state capable of switching between normal rotation and reverse rotation of the motor. .   The electric power tool according to claim 1, wherein the control unit sets the detection of the lock of the motor as a condition necessary for entering the forward / reverse switchable state.   The electric tool according to claim 2, wherein the control unit is in a reverse rotation prohibiting state in which the motor is prevented from rotating in reverse when the motor performs a predetermined reverse rotation operation in the forward / reverse switching enabled state.   The electric power tool according to any one of claims 1 to 3, wherein the controller performs a predetermined reverse operation when the motor is reversely rotated.   The electric power tool according to claim 3 or 4, wherein the predetermined reverse rotation operation is an operation of reverse rotation for a predetermined time and stopping.   5. The electric tool according to claim 3, wherein the predetermined reverse rotation operation is an operation in which the rotary blade is reversely rotated and stopped so as to rotate from half rotation to one rotation.   The power tool according to any one of claims 3 to 6, wherein in the predetermined reverse rotation operation, electric power is supplied to the motor with a duty within a range of 30 to 70%.   The power tool according to any one of claims 1 to 7, further comprising a manual switch for switching the motor to reverse rotation.   The power tool according to any one of claims 1 to 8, further comprising a notification unit that notifies the outside of a direction in which the control unit rotates the motor.   An electric tool comprising a motor, a rotary blade rotated by the motor, and a control unit that controls the motor, wherein the control unit enters a reverse rotation mode when detecting the lock of the motor.