JP2020203327A - Power tool - Google Patents

Abstract

To provide a power tool capable of improving operability and workability.SOLUTION: A thread fastening machine 1 includes: a motor 3 which has a rotary shaft 31 rotating in a normal rotation direction and a reverse rotation direction; an output shaft section 6 to/from which a tip tool P can be attached/detached and which is driven by receiving driving force of the motor 3; and a control section 4 which switchably controls the rotation direction of the rotary shaft 31 between the normal rotation direction and the reverse rotation direction. The control section 4 is configured to be switchable between a plurality of modes including a first mode and a second mode by controlling the motor 3. When the control section 4 controls the rotary shaft 31 to rotate in the reverse rotation direction when an operation mode is the first mode, an operation mode of the thread fastening machine 1 is configured to be switchable from the first mode to the second mode. When the control section 4 controls the rotary shaft 31 to rotate in the normal rotation direction, the operation mode of the thread fastening machine 1 is maintained in the first mode.SELECTED DRAWING: Figure 3

Description

The present invention relates to a power tool.

Conventionally, a plate material such as gypsum board is applied to the ceiling or wall by screwing, but a screw tightening machine is widely used as an electric tool for screwing. For example, Patent Document 1 includes a motor and an output shaft that rotates by receiving a driving force from the motor, and an on-lock button for holding a switch operated by an operator in a pulled state during work is operated from the outside. Possible connecting screw drivers are disclosed. In the connecting screw driver of Patent Document 1, by providing the on-lock button, for example, when tightening a large number of screws continuously, it is possible to omit the operation of the switch by the operator.

Japanese Unexamined Patent Publication No. 2006-116626

However, the connecting screw driver of Patent Document 1 is configured to be able to maintain the on state of the switch regardless of whether the output shaft that receives the driving force of the motor rotates forward or reverse. Therefore, for example, when the on state is unintentionally held when the output shaft is reversed, the tip tool mounted on the output shaft continues to rotate, so that the tip tool is fastened to the work piece. It became difficult to engage with a tool (for example, a screw or the like), and operability and workability were deteriorated.

Further, in the connecting screw driver described in Patent Document 1, in order to maintain the on state of the switch, it is necessary to operate the on-lock button in addition to the switch, which deteriorates the operability and workability. .. In particular, since the on-lock button needs to be provided so as to protrude from the tool body so that it can be operated from the outside, it becomes an obstacle when the operator grips the handle, and the operability and workability are deteriorated. ..

Therefore, an object of the present invention is to provide a power tool capable of improving operability and workability.

In order to solve the above problems, the present invention includes a motor having a rotating shaft that rotates in the first direction and the second direction, an output shaft that can be attached to and detached from a tip tool and is driven by receiving the driving force of the motor, and the above. An electric tool having a control unit that controls the rotation direction of the rotation shaft so as to be switchable between the first direction and the second direction, and the control unit controls an operation mode by controlling the motor. Is switchable between a plurality of operation modes including the first mode and the second mode, and in the case of the first mode, the control unit controls the rotation axis to rotate in the first direction. Occasionally, it is configured to be switchable from the first mode to the second mode, and when the control unit controls the rotation axis to rotate in the second direction, the mode is maintained in the first mode. We provide electric tools to rotate.

According to the power tool having the above configuration, when the rotation shaft of the motor rotates in the first direction, the mode can be switched from the first mode to the second mode, while the rotation shaft of the motor rotates in the second direction. Maintains the first mode. As a result, for example, when the output shaft driven by receiving the driving force of the motor is reversed, it is possible to realize a configuration that does not shift to the operation mode in which the motor maintains the rotating state. For example, it can be suitably engaged with a screw or the like), and operability and workability can be improved. On the other hand, when the output shaft that is driven by receiving the driving force of the motor rotates in the normal direction, it is possible to realize a configuration that shifts to the operation mode in which the state in which the motor is driven is maintained. It is possible to omit the operation of starting the motor, and the operability and workability are improved.

The power tool having the above configuration is capable of switching between an on state and an off state, and further has an operation unit for controlling the start and stop of the motor, and the control unit is from the first mode to the first mode. When a predetermined operation for switching to the two modes is performed on the operation unit and the control unit controls the rotation axis to rotate in the first direction, the first mode to the second mode It is preferable to switch to.

According to such a configuration, the operation mode of the power tool is changed from the first mode to the second mode by performing a predetermined operation on the operation unit for starting or stopping the motor which is generally operated by the operator during work. It is possible to switch to the mode. Therefore, when switching the mode of the power tool from the first mode to the second mode, it is not necessary for the operator to change hands, and the operability and workability are improved. Further, it is not necessary to provide other members and mechanisms for switching the operation mode, and the number of parts can be reduced.

Further, it is preferable that the predetermined operation is an operation in which the on operation for switching the operation unit from the off state to the on state is performed a predetermined number of times within a predetermined time.

According to such a configuration, the operation can be shifted to the second mode by a simple operation of switching the operation unit from the off state to the on state a predetermined number of times within a predetermined time, so that the operability and workability can be improved. Can be improved.

Further, when the on operation is performed on the operation unit while the motor is being driven in the state where the operation mode is the second mode, the control unit releases the state of operating in the second mode. It is preferable to do so.

According to such a configuration, since the state in which the power tool operates in the second mode can be released by operating the operation unit, it is not necessary for the operator to change hands, and the operability and workability are improved. Further, it is not necessary to provide another member and mechanism for canceling the second mode, and the number of parts can be reduced.

Further, when the motor is driven in the state where the operation mode is the second mode, the on operation is performed on the operation unit, and the off operation for switching the operation unit from the on state to the off state is performed. In this case, it is preferable that the control unit releases the state of operating in the second mode.

According to such a configuration, since the state in which the power tool operates in the second mode can be released by operating the operation unit, it is not necessary for the operator to change hands, and the operability and workability are improved. In addition, the state in which the power tool operates in the second mode is released in response to a series of operations of shifting the operation unit from the off state to the on state (on operation) and then shifting to the off state again (off operation). Therefore, operability and workability are improved. Further, it is not necessary to provide other members and mechanisms for canceling the second mode, and the number of parts can be reduced.

Further, the control unit further includes a connection unit that is electrically connected to the external power supply, and the control unit is in the first mode when the on state is maintained and the connection unit is electrically connected to the external power supply. And it is preferable to switch between the second modes.

According to such a configuration, the power tool is operated in a specific operation mode by a combination of operations and operations normally performed by an operator during work, such as an operation of connecting the connection portion of the power tool to an external power source and an operation of the operation unit. Therefore, operability and workability are improved. Further, it is not necessary to provide other members and mechanisms for switching the operation mode of the power tool, and the number of parts can be reduced.

Further, the control unit further includes a connection unit that is electrically connected to the external power supply, and the control unit operates the predetermined operation when the on state is maintained and the connection unit is electrically connected to the external power supply. Is performed on the operation unit, and when the control unit controls the rotation axis to rotate in the first direction, a permission state capable of switching from the first mode to the second mode and the predetermined state. Operation is performed on the operation unit, and even when the control unit controls the rotation axis to rotate in the first direction, switching between the operation unit and the disallowed state for maintaining the first mode. Is preferable.

According to such a configuration, when the operator considers that it is unnecessary to switch the operation mode of the power tool from the first mode to the second mode, the operation and operation unit for connecting the connection portion of the power tool to the external power supply. Since the power tool can be operated in a specific operation mode by a combination of the work and the operation normally performed by the operator during the work, the operability and workability are improved. Further, by shifting the state of the power tool to the disallowed state, the power tool does not unintentionally operate in the second mode, and the operability and workability are improved. Further, since the state of the power tool is switched between the permitted state and the disallowed state, it is not necessary to provide other members and mechanisms, and the number of parts can be reduced.

Further, it further has a connection portion electrically connected to an external power source, and a changeover switch configured to be manually operated and capable of switching the rotation direction of the motor.
When the connection unit is electrically connected to the external power supply, the control unit preferably switches between the first mode and the second mode according to the state of the changeover switch.

According to such a configuration, the power tool is specified by the combination of the work and the operation normally performed by the operator during the work, such as the operation of connecting the power tool connection part to the external power source, the operation of the changeover switch, and the operation of the operation part. Since it can be operated in the operation mode, operability and workability are improved. Further, it is not necessary to provide other members and mechanisms for switching the operation mode of the power tool, and the number of parts can be reduced.

Further, the changeover switch further includes a connection portion electrically connected to an external power source and a changeover switch configured to be manually operated and capable of switching the rotation direction of the motor, and the changeover switch is manually operated. By doing so, the motor is configured to be switchable between a first state for making the rotation direction the first direction and a second state for making the rotation direction the second direction, and the control unit is the control unit. When the changeover switch is in the first state and the connection portion is electrically connected to the external power supply, the predetermined operation is performed on the operation unit, and the control unit connects the rotation shaft to the first. A permission state in which the first mode can be switched to the second mode when controlled to rotate in a direction, and the predetermined operation is performed on the operation unit, and the control unit controls the rotation axis. Even when controlling to rotate in the first direction, it is preferable to switch between the disallowed state for maintaining the first mode.

According to such a configuration, when the operator thinks that it is unnecessary to switch the operation mode of the power tool from the first mode to the second mode, the operation of connecting the connection part of the power tool to the external power supply, the changeover switch. Since the power tool can be operated in a specific operation mode by a combination of the work and the operation normally performed by the operator during the work, such as the operation for the operation and the operation for the operation unit, the operability and workability are improved. Further, by shifting the state of the power tool to the disallowed state, the power tool does not unintentionally operate in the second mode, and the operability and workability are improved. Further, since the state of the power tool is switched between the permitted state and the disallowed state, it is not necessary to provide other members and mechanisms, and the number of parts can be reduced.

The present invention further comprises a motor having a rotating shaft, an output shaft to which a tip tool can be attached and detached and driven by receiving the driving force of the motor, and a manually operable structure that can be switched between an on state and an off state. It is an electric tool having an operation unit for controlling the start and stop of the motor, a connection unit electrically connected to an external power source, and a control unit for controlling the motor. Is configured to be switchable between a plurality of operation modes including the first mode and the second mode by controlling the motor, the on state is maintained, and the connection portion is electrically connected to the external power supply. Then, a power tool characterized by switching between the first mode and the second mode is provided.

According to the power tool having the above configuration, the power tool is operated in a specific operation mode by a combination of operations and operations normally performed by an operator during work, such as an operation of connecting the connection portion of the power tool to an external power source and an operation of the operation unit. Therefore, operability and workability are improved. Further, it is not necessary to provide other members and mechanisms for switching the operation mode of the power tool, and the number of parts can be reduced.

The present invention further electrically connects a motor having rotating shafts rotating in the first and second directions, an output shaft to which a tip tool can be attached and detached and driven by receiving the driving force of the motor, and an external power source. A connection unit to be connected, a control unit that controls the rotation direction of the motor so as to be switchable between the first direction and the second direction, and a control unit that can be manually operated so that the rotation direction of the motor can be switched. An electric tool having a configured changeover switch, wherein the control unit is configured to be switchable between a plurality of operation modes including a first mode and a second mode by controlling the motor, and the connection is made. Provided is an electric motor characterized by switching between the first mode and the second mode according to the state of the changeover switch when the unit is electrically connected to the external power source.

According to the power tool having the above configuration, the power tool is specified by the combination of the work and operation normally performed by the operator during the work, such as the operation of connecting the power tool connection part to the external power source, the operation of the changeover switch, and the operation of the operation part. Since it can be operated in the operation mode of, operability and workability are improved. Further, it is not necessary to provide other members and mechanisms for switching the operation mode of the power tool, and the number of parts can be reduced.

According to the power tool of the present invention, it is possible to improve operability and workability.

It is sectional drawing which shows the internal structure of the screw tightening machine which concerns on 1st Embodiment of this invention. It is a circuit diagram which includes the block diagram which shows the electrical structure of the screw tightening machine which concerns on 1st Embodiment of this invention. It is a flowchart which shows the control to the motor by the control part of the screw tightening machine which concerns on 1st Embodiment of this invention. It is a flowchart which shows the 1st modification of the control with respect to the motor by the control part of the screw tightening machine which concerns on 1st Embodiment of this invention. It is a flowchart which shows the 2nd modification of the control with respect to the motor by the control part of the screw tightening machine which concerns on 1st Embodiment of this invention. It is a table which shows the mode changeover pattern according to the state of the trigger switch and the forward / reverse switch of the screw tightening machine which concerns on 2nd Embodiment of this invention. It is a flowchart which shows the control to the motor by the control part of the screw tightening machine which concerns on 2nd Embodiment of this invention. It is a flowchart which shows the modification of the control with respect to the motor by the control part of the screw tightening machine which concerns on 2nd Embodiment of this invention.

Hereinafter, the screw tightening machine 1 which is an example of the power tool according to the embodiment of the present invention will be described with reference to FIGS. 1 to 5. The screw tightening machine 1 is an electric power tool for screwing a plate material such as gypsum board to a ceiling or a wall, for example.

In the following description, "front" shown in the figure is defined as forward, "rear" is defined as backward, "up" is defined as upward, and "down" is defined as downward. Further, when the screw tightening machine 1 is viewed from the rear, "right" is defined as the right direction, and "left" is defined as the left direction. Further, regarding the rotatable member, the rotation in the clockwise direction is defined as "forward rotation" and the rotation in the counterclockwise direction is defined as "reversal" in the rear view of the screw tightening machine 1. When the dimensions, numerical values, etc. are referred to in the present specification, not only the dimensions and numerical values that completely match the dimensions and numerical values, but also the dimensions, numerical values, etc. that substantially match (for example, within the range of manufacturing error). Case) shall be included. Similarly, for "identical", "orthogonal", "parallel", "match", "plane", "same diameter", etc., "approximately identical", "approximately orthogonal", "approximately parallel", "approximately coincident", etc. It shall include "approximately flush", "approximately the same diameter", etc.

As shown in FIG. 1, the screw tightening machine 1 is centered on a housing 2, a motor 3, a control unit 4, a clutch unit 5, and an axis B to which a tip tool P can be attached and detached and extends in the front-rear direction. It mainly includes a rotatable output shaft portion 6.

The housing 2 forms the outer shell of the screw tightening machine 1, and mainly includes a motor housing 21, a handle housing 22, a gear housing 23, and a cover 24.

The motor housing 21 has a cylindrical shape extending in the front-rear direction, and houses the motor 3 and the control unit 4. A plurality of intake ports are formed at the rear portion of the motor housing 21 (not shown).

The handle housing 22 is formed in a substantially U-shape in a side view, and has a grip portion 221, a first connection portion 222, and a second connection portion 223.

The grip portion 221 is a portion gripped by the operator during work. The grip portion 221 forms the rear portion of the handle housing 22 and extends in the vertical direction. A trigger switch 22A operated by an operator is provided in the upper part of the front portion of the grip portion 221, and a start signal output unit 22B electrically connected to the control unit 4 is provided inside the grip portion 221. The start signal output unit 22B controls a tool start signal for starting the motor 3 when the trigger switch 22A is pulled, that is, started (for example, when the trigger switch 22A is pushed into the grip portion 221 by the operator's finger). When the pull operation on the trigger switch 22A is released, that is, the stop operation is performed by outputting to the unit 4 (for example, when the operator releases the pull operation by releasing the finger from the trigger switch 22A), the tool drive signal to the control unit 4 is released. Is configured to stop the output of. In the following description, the state in which the trigger switch 22A is being pulled is referred to as the "on state", and the state in which no external force is applied to the trigger switch 22A (the state in which the pulling operation is not performed). Is called the "off state". The on state is an example of the "on state" in the present invention, and the off state is an example of the "off state" in the present invention.

The second connecting portion 223 connects the lower portion of the grip portion 221 and the lower portion of the rear portion of the motor housing 21, and has a substantially cylindrical shape extending in the front-rear direction. The second connection unit 223 is provided with a changeover switch 22C operated by an operator, and inside the second connection unit 223, a forward / reverse signal output unit 22D electrically connected to the control unit 4 is provided. There is. The changeover switch 22C is a lever switch for switching the rotation direction (forward rotation and reverse rotation) of the motor 3 during work, and is provided on the right side surface of the second connection portion 223 so as to be manually operated from the outside. When the changeover switch 22C is tilted in the clockwise direction of the paper in FIG. 1, the forward / reverse signal output unit 22D outputs a forward signal for rotating the motor 3 in the forward direction to the control unit 4, and in the counterclockwise direction of the paper in FIG. When the changeover switch 22C is tilted down, it is configured to output an inversion signal that inverts the motor 3. In other words, the changeover switch 22C is configured to be switchable between a first state for making the rotation direction of the motor 3 a forward rotation direction and a second state for making a reverse rotation direction by being manually operated. ing. The changeover switch 22C is an example of the "changeover switch" in the present invention. The first state is an example of the "second state" in the present invention, and the second state is an example of the "first state" in the present invention.

Further, a power cord 2A connected to the external power supply Q (see FIG. 2) extends from the lower rear portion of the second connection portion 223. The power cord 2A includes a connection plug (not shown) that can be connected to an external power source, and is configured to be connectable to the external power source Q. In the present embodiment, the trigger switch 22A is pulled to supply electric power from the external power supply Q to the motor 3 via the power cord 2A. The external power supply Q may be any power supply that outputs an AC voltage, and is not limited to a commercial AC power supply. For example, the external power source Q may be a generator or the like that generates an AC voltage.

The gear housing 23 is formed in a substantially funnel shape that extends in the front-rear direction and tapers from the rear end toward the front. The rear portion of the gear housing 23 is connected to the front end portion of the motor housing 21 via a plurality of screws 2B (the point that a plurality of screws 2B are provided is not shown). The gear housing 23 accommodates the front portion (pinion 32) of the motor 3, the clutch portion 5, and the rear portion of the output shaft portion 6. Further, a plurality of exhaust ports (not shown) are formed at the rear portion of the gear housing 23.

Further, a spring clutch 25 is fixed inside the gear housing 23. The spring clutch 25 has a substantially cylindrical shape extending in the front-rear direction, and the output shaft portion 6 is inserted therethrough. The spring clutch 25 is configured so that the regulation and the permissible of the forward rotation of the output shaft portion 6 can be switched according to the position of the output shaft portion 6 in the front-rear direction.

The cover 24 is made of resin and is formed in a substantially funnel shape that tapers from the rear end toward the front. The cover 24 is fitted into the gear housing 23 so as to cover the outer peripheral surface of the front portion of the gear housing 23.

The motor 3 is a brushless motor configured so that the rotation direction (forward rotation and reverse rotation) can be switched. The motor 3 has a rotating shaft 31, a pinion 32, a rotor 33, a stator 34, a sensor substrate 35, and a fan 36. The motor 3 may be a motor with a brush. The motor 3 is an example of the "motor" in the present invention. The forward rotation direction is an example of the "second direction" in the present invention, and the reverse rotation direction is an example of the "first direction" in the present invention.

The rotation shaft 31 extends in the front-rear direction. The rear end of the rotating shaft 31 is supported by the motor housing 21 via the bearing 31B, and the front end of the rotating shaft 31 is supported by the gear housing 23 via the bearing 31A. In other words, the rotating shaft 31 is rotatably supported by the housing 2 about the axis A, and is rotated by the drive of the motor 3 to generate a rotational force. Here, the axis A is a line that extends in the front-rear direction and passes through the axis of the rotating shaft 31. The rotating shaft 31 is an example of the "rotating shaft" in the present invention.

The pinion 32 is provided at the front end of the rotating shaft 31 so as to be integrally rotatable with the rotating shaft 31. Further, behind the pinion 32, a fan 36 is provided so as to be rotatable coaxially with the rotating shaft 31. In the present embodiment, when the fan 36 rotates, outside air is taken into the housing 2 from an intake port (not shown) formed in the motor housing 21, and the gear housing 23 cools each component of the motor 3. It is configured to exhaust air from an exhaust port (not shown) formed in the housing.

The rotor 33 is a rotor having a plurality of permanent magnets 33A (see FIG. 2), and is provided on the rotating shaft 31 so as to be integrally rotatable with the rotating shaft 31. Further, a sensor magnet (not shown) is provided at the rear end of the rotor 33 so as to rotate integrally with the rotor. The stator 34 is a stator having a stator winding 34A (see FIG. 2) and is fixed to the motor housing 21. The stator winding 34A is star-shaped and is composed of a U phase, a V phase, and a W phase. Each of the upper portion and the lower portion of the outer peripheral portion of the stator 34 is fixed to the motor housing 21 by bolts (not shown).

The sensor substrate 35 is a substrate having a substantially annular shape when viewed from the front, and is provided behind the rotor 33 and the stator 34. Three magnetic sensors 35A to 35C (see FIG. 2) are provided on the side surface (front surface) of the sensor substrate 35 facing the rotor 33. The magnetic sensors 35A to 35C are, for example, Hall elements. The magnetic sensors 35A to 35C are arranged side by side on the front surface of the sensor substrate 35 at intervals of approximately 60 degrees in the circumferential direction of the rotating shaft 31. The magnetic sensors 35A to 35C are connected to the control unit 4 via the wiring 35D, and output a signal for detecting the rotational position of the sensor magnet (not shown) of the rotor 33 to the control unit 4.

As shown in FIG. 1, the control unit 4 is provided at the rear portion of the motor 3 and has a substrate case 40. The substrate case 40 has a substantially rectangular parallelepiped shape with the front open, and is arranged in the motor housing 21 so that the shortest side thereof is parallel to the front-rear direction. A circuit board (not shown) is housed in the board case 40. The circuit board is arranged in the board case 40 so that both sides thereof are orthogonal to the front-rear direction, and a microcomputer 10 or the like for controlling the motor 3 is mounted.

Further, the control unit 4 controls the rotation direction of the rotation shaft 31 of the motor 3 so as to be switchable between the normal rotation direction and the reverse rotation direction, and can switch the operation mode of the screw tightening machine 1 between a plurality of modes. It is configured. In the present embodiment, the screw tightening machine 1 has a "normal mode" and an "on-lock mode" as operation modes. In the normal mode, when power is supplied to the control unit 4, when the trigger switch 22A is in the ON state, the control unit 4 supplies power to the motor 3 and controls the drive of the motor 3, while the trigger switch 22A Is an operation mode in which the control unit 4 does not supply electric power to the motor 3 (cuts off the electric power supply) and stops driving the motor 3 when is in the off state. On the other hand, in the on-lock mode, when power is supplied to the control unit 4, the control unit 4 supplies power to the motor 3 and controls the drive of the motor 3 regardless of the state of the trigger switch 22A. The mode. The operation mode of the screw tightening machine 1 is not limited to the above-mentioned "normal mode" and "on-lock mode". For example, the mode can be switched between the "high rotation speed mode" in which the rotation speed of the rotation shaft 31 of the motor 3 is higher than the "normal mode" and the "on-lock mode" and the "low rotation speed mode" in which the rotation speed is lower. It may be configured in. Further, for example, the operation mode of the screw tightening machine 1 may include a "light-on mode" for driving a light for illuminating a work material during work and a "light-off mode" for stopping the driving of the light. The electrical configuration of the control unit 4 will be described later.

As shown in FIG. 1, the clutch portion 5 includes a clutch drum 51 and a multi-plate friction clutch 52. The clutch drum 51 has a substantially cylindrical shape extending in the front-rear direction and having an opening formed in the front portion, and is rotatably supported about the axis B via a bearing 5A and a bearing metal 5B. Here, the axis B is a line extending in the front-rear direction and passing through the axis of the output shaft portion 6. An engaging portion 51A is provided on the inner peripheral surface of the front portion of the clutch drum 51, a gear portion 51B is provided on the outer peripheral surface of the substantially central portion, and a one-way clutch 51C is provided on the inner peripheral surface of the substantially central portion. , A spring 51D is housed in the rear part.

The engaging portion 51A extends in the front-rear direction on the inner peripheral surface of the front portion of the clutch drum 51. Although not shown in detail in the figure, the engaging portion 51A has a groove that is recessed outward in the radial direction of the clutch drum 51 from the inner peripheral surface of the clutch drum 51 and extends in the front-rear direction in the entire circumferential direction of the clutch drum 51. It is formed at predetermined intervals.

The gear portion 51B has a plurality of gear teeth and meshes with the pinion 32 of the motor 3. As a result, the rotational force from the motor 3 is transmitted to the clutch drum 51 to drive the clutch drum 51 in rotation. The one-way clutch 51C has an outer ring portion fixed (press-fitted) to the inner peripheral surface of the clutch drum 51, and an inner ring portion in which normal rotation is restricted with respect to the outer ring portion and reverse rotation is permitted.

The spring 51D is arranged inside the rear portion of the clutch drum 51 so as to be expandable and contractible in the front-rear direction. The rear end of the spring 51D is in contact with the wall forming the rear end of the clutch drum 51, and the front end is in contact with the rear end of the output shaft 6 to urge the output shaft 6 forward.

The multi-plate friction clutch 52 is housed in a clutch drum 51, and is configured by alternately laminating an outer plate formed in a substantially disk shape and an inner plate formed in a substantially disk shape in the front-rear direction. Although not shown in detail in the figure, each of the plurality of outer plates has a substantially annular shape in the front view, and an engaged portion capable of engaging with the engaging portion 51A of the clutch drum 51 is formed on the outer peripheral portion of the outer plate. It is provided at predetermined intervals in the circumferential direction. Further, each of the plurality of inner plates has a substantially annular shape in the front view, and an engaged portion that projects inward in the radial direction of the inner plate is provided on the inner peripheral portion thereof. The engaged portions of the inner plate are provided at predetermined intervals in the circumferential direction of the inner plate. Further, since the outer plate and the inner plate are laminated in the front-rear direction, a through hole 52a extending in the front-rear direction is formed at a substantially central portion in the radial direction of the multi-plate friction clutch 52.

The multi-plate friction clutch 52 is configured to be able to transmit the rotational force of the clutch drum 51 that rotates by receiving the rotational force of the motor 3 to the output shaft portion 6 by being pressed in the front-rear direction. Specifically, the multi-plate friction clutch 52 is provided between the clutch drum 51 and the output shaft portion 6 in the transmission path of the driving force (rotational force) of the motor 3, and the output shaft portion 6 moves rearward. In addition to being pressed, the driving force of the motor 3 is transmitted to the output shaft portion 6 in response to the pressing force.

The output shaft portion 6 is configured so that the tip tool P can be attached and detached and can be driven by receiving the driving force of the motor 3. As shown in FIG. 1, the rear portion of the output shaft portion 6 is housed in the gear housing 23, and the front portion thereof extends forward from the front portion of the gear housing 23. The output shaft portion 6 has a spline shaft 61 and a bit mounting portion 62. The tip tool P is an example of the "tip tool" in the present invention. The output shaft portion 6 is an example of the “output shaft” in the present invention.

The bit mounting portion 62 has a substantially cylindrical shape extending in the front-rear direction, and is supported by a spring clutch 25 so as to be rotatable around the axis B as a rotation center and movable in the front-rear direction. The bit mounting portion 62 is formed with a through hole 62a extending in the front-rear direction.

The spline shaft 61 has a substantially cylindrical shape extending in the front-rear direction, and is inserted into a through hole 52a of the multi-plate friction clutch 52. The front end of the spline shaft 61 is press-fitted into the through hole 62a of the bit mounting portion 62, and the rear end of the spline shaft 61 is supported by a one-way clutch 51C provided on the clutch drum 51 so as to be rotatable and movable in the front-rear direction. Has been done.

Further, an engaging portion 61A extending in the front-rear direction is provided at a substantially central portion of the spline shaft 61 in the front-rear direction. The engaging portion 61A is formed with projecting portions extending outward in the radial direction of the spline shaft 61 from the outer peripheral surface of the spline shaft 61 and extending in the front-rear direction at predetermined intervals over the entire circumferential direction of the spline shaft 61. The engaging portion 61A is engaged with an engaging portion (not shown) provided on the plurality of inner plates, and when the plurality of inner plates rotate, the engaging portion 61A and the plurality of inner plates, the spline shaft 61, and the bit mounting portion 62 Rotates integrally.

Next, the electrical configuration of the screw tightening machine 1 and the external power supply Q will be described with reference to FIG. The screw tightening machine 1 has a power supply circuit 9 and a microcomputer 10 as shown in FIG. The power supply circuit 9 and the microcomputer 10 are mounted on a circuit board housed in a board case 40.

The power supply circuit 9 is configured to be able to supply the power of the external power supply Q to the motor 3, and includes a noise filter circuit 42, a rectifier circuit 43, a plus line 44, a minus line 46, a smoothing circuit 47, and a shunt. It has a resistor 45, an inverter circuit 48, and a constant voltage power supply circuit 49.

The noise filter circuit 42 is a circuit for reducing noise, and has a first terminal 42B, a second terminal 42C, a choke coil 42D, and a capacitor 42E. The first terminal 42B and the second terminal 42C are terminals to which the voltage of the external power supply Q is applied while the power cord 2A is connected to the external power supply Q. That is, the first terminal 42B and the second terminal 42C are electrically connected to the external power supply Q. The first terminal 42B and the second terminal 42C are examples of the "connection portion" in the present invention.

The choke coil 42D and the capacitor 42E are filter elements for reducing noise propagating from the external power supply Q to the power supply circuit 9. The choke coil 42D is connected in series between the rectifier circuit 43 and the external power supply Q, and the capacitor 42E is connected in parallel with the external power supply Q.

The rectifier circuit 43 is a diode bridge circuit having four diodes 43A (four rectifier elements), and rectifies the AC voltage output from the external power supply Q via the noise filter circuit 42 and outputs the AC voltage to the smoothing circuit 47. In other words, the rectifier circuit 43 converts the AC voltage of the external power supply Q into a DC voltage and outputs it to the smoothing circuit 47.

The plus line 44 connects the rectifier circuit 43 and the inverter circuit 48. Further, the minus line 46 is connected to a GND (not shown), and also connects the rectifier circuit 43 and the inverter circuit 48.

The smoothing circuit 47 is connected between the rectifier circuit 43 and the inverter circuit 48, smoothes the DC voltage output from the rectifier circuit 43, and outputs the DC voltage to the inverter circuit 48. The smoothing circuit 47 has a first capacitor 47A, a second capacitor 47B, and a resistor 47C.

The first capacitor 47A is a polar electrolytic capacitor and is connected between the plus line 44 and the minus line 46.

The second capacitor 47B is a non-polar film capacitor and is connected between the plus line 44 and the minus line 46.

The resistor 47C is a resistor for discharging, is connected between the plus line 44 and the minus line 46, and is connected in parallel with the second capacitor 47B.

The shunt resistor 45 is provided between the smoothing circuit 47 and the inverter circuit 48 on the minus line 46. The shunt resistor 45 is a resistor used to detect the current flowing through the motor 3, and both ends of the shunt resistor 45 are connected to the microcomputer 10.

The inverter circuit 48 has six switching elements Q1 to Q6 connected in a three-phase bridge type. In the present embodiment, the switching elements Q1 to Q6 are MOSFETs (Metal Oxide Semiconductor Field Effect Transistor), but are not limited to these, and may be switching elements such as an IGBT (Insulated Gate Bipolar Transistor).

Each gate of the switching elements Q1 to Q6 is connected to the microcomputer 10, and performs a switching operation based on a control signal input from the microcomputer 10. Further, each drain or each source of the switching elements Q1 to Q6 is connected to the stator coils U, V, and W.

As shown in FIG. 5, the constant voltage power supply circuit 49 is connected between the plus line 44 and the minus line 46. The constant voltage power supply circuit 49 has a diode 49A, a capacitor 49B, an IPD circuit 49C, a capacitor 49D, and a regulator 49E, and converts the DC voltage output from the rectifier circuit 43 to generate a stabilized reference voltage. Then, it is supplied to the microcomputer 10 and the like.

The microcomputer 10 has a calculation unit, a ROM, a RAM, and the like (not shown), and is configured to control the inverter circuit 48 to drive the motor 3. The microcomputer 10 detects the rotational position of the rotor 33 by detecting the rotational position of the sensor magnet (not shown) of the rotor 33 based on the signals output from each of the three Hall elements 35A, 35B, and 35C. A control signal for switching on / off of each of the switching elements Q1 to Q6 is formed based on the detection result. The microcomputer 10 outputs the control signal to the switching elements Q1 to Q6, sequentially switches the energized coils of the stator coils U, V, and W, and drives the rotor 33 to rotate in a predetermined rotation direction. Further, the microcomputer 10 has a timer counter function for measuring the time from the reception of the tool start signal from the start signal output unit 22B.

Various control programs, various data, various threshold values, and the like for controlling the drive of the motor 3 are stored in the ROM (not shown) of the microcomputer 10. Further, the RAM (not shown) has a storage area for temporarily storing data. In the present embodiment, the RAM is configured to temporarily store the time from when the trigger switch 22A is turned on to when it is turned off by the operation of the operator.

The start signal output unit 22B is electrically connected to the microcomputer 10, detects a pulling operation on the trigger switch 22A, and outputs a tool start signal to the microcomputer 10. The forward / reverse signal output unit 22D is electrically connected to the microcomputer 10, detects an operation on the changeover switch 22C, and outputs a forward rotation signal and a reverse rotation signal to the microcomputer 10.

Next, with reference to FIG. 1, the screw tightening work and the operation of the screw tightening machine 1 during the tightening work using the screw tightening machine 1 to a work material (plate material or the like) (not shown) will be described. In the following description, unless otherwise specified, it is assumed that the direction in which the tip tool P is pressed against the screw (that is, the direction in which the screw tightening machine 1 is pushed toward the screw) and the forward direction are the same.

When tightening the screw, the operator first attaches the tip tool P to the through hole 62a of the bit mounting portion 62 of the output shaft portion 6, tilts the changeover switch 22C counterclockwise on the paper surface, and triggers the switch 22A. Perform a pull operation on. Then, electric power is supplied to the motor 3 from an external power source (not shown) via the power cord 2A, and the motor 3 starts driving. When the motor 3 starts driving, the rotating shaft 31 and the pinion 32 reverse around the axis A as the center of rotation. As the pinion 32 is reversed, the clutch drum 51 rotates forward about the axis B via the gear portion 51B that meshes with the pinion 32. Along with the normal rotation of the clutch drum 51, the plurality of outer plates engaged (engaged) with the engaging portion 51A of the clutch drum 51 rotate forward with the axis B as the rotation axis.

In this state, the operator engages the tip of the tip tool P with a groove (for example, a cross groove) formed in the screw head of the screw. After that, the operator pushes the main body of the screw tightening machine 1 toward the screw and pushes the tip tool P against the screw. At this time, the output shaft portion 6 (spline shaft 61 and bit mounting portion 62) moves rearward against the urging force of the spring 51D. When the output shaft portion 6 moves rearward, the rear end of the bit mounting portion 62 and the inner plate located at the foremost end of the multi-plate friction clutch 52 come into contact with each other. At this time, the adjacent outer plates and inner plates of the multi-plate friction clutch 52 come into contact with each other.

In this state, when the output shaft portion 6 moves further rearward as the main body of the screw tightening machine 1 is further pushed into the screw, the surface pressure on the contact surface between the outer plate and the inner plate adjacent to each other in the front-rear direction increases. To rise. At this time, due to the frictional force generated between the outer plate and the inner plate due to the normal rotation of the outer plate, the rotational force of the motor 3 transmitted to the outer plate is transmitted to the inner plate, and the output rotates integrally with the inner plate. The shaft portion 6 rotates. Then, the rotational force from the motor 3 is transmitted to the tip tool P via the bit mounting portion 62 of the output shaft portion 6, and the screw can be tightened to the work piece (not shown).

Further, when the screw tightening work is completed and the operator separates the tip tool P from the screw head of the screw, the output shaft portion 6 moves forward by the urging force of the spring 51D. As a result, the pressure on the multi-plate friction clutch 52 in the front-rear direction is eliminated, and the surface pressure on the contact surfaces of the adjacent outer plates and inner plates in the front-rear direction is reduced, so that the pressure is generated between the adjacent outer plates and the inner plates. Friction is reduced.

On the other hand, when loosening the screw, the changeover switch 22C is tilted clockwise on the paper to pull the trigger switch 22A. At this time, if the operator can sufficiently press the tip tool P against the screw, the output shaft portion 6 moves backward by pressing the tip tool P against the screw. Then, as the rear end portion of the bit mounting portion 62 of the output shaft portion 6 presses the multi-plate friction clutch 52 rearward, the surface pressure between the outer plate and the inner plate adjacent to each other in the front-rear direction increases. Friction occurs between the adjacent outer plate and inner plate as the outer plate is inverted. Due to this friction, the inner plate is inverted, and the output shaft portion 6 is also inverted due to the engagement between the engaged portion (not shown) of the inner plate and the engaging portion 61A of the spline shaft 61. Therefore, the rotational force from the motor 3 is transmitted to the tip tool P via the bit mounting portion 62 of the output shaft portion 6, and the screw can be loosened.

When loosening a screw, the screw head of the screw does not protrude from the work material (for example, when the screw is buried in the work material), and the operator sufficiently attaches the tip tool P to the screw. If it cannot be pressed, the bit mounting portion 62 cannot be sufficiently moved rearward, and sufficient friction does not occur between the outer plate and the inner plate. In this case, the rotational force of the motor 3 cannot be transmitted from the clutch drum 51 to the output shaft portion 6 via the outer plate and the inner plate, but the clutch drum 51 is inverted, so that the clutch drum 51 is inverted, so that the clutch drum 51 is reversed via the one-way clutch 51C. The rotational force is transmitted from the clutch drum 51 to the spline shaft 61, and the screws can be loosened.

Next, with reference to FIG. 3, a specific process of operation mode switching control of the screw tightening machine 1 by the control unit 4 during work will be described. FIG. 3 is a flowchart showing control of the motor 3 by the control unit 4. Unless otherwise specified, the operation mode of the screw tightening machine 1 is assumed to be a normal mode.

When the operator inserts a plug (not shown) of the power cord 2A into the external commercial power supply Q, the screw tightening machine 1 and the external commercial power supply Q are electrically connected via the first terminal 42B and the second terminal 42C (see FIG. 2). Connected to. As a result, electric power is supplied to the microcomputer 10 (control unit 4), and the process shown in the flowchart of FIG. 3 is started with this as an opportunity.

In step S101, the microcomputer 10 determines the state of the changeover switch 22C. Specifically, it is determined whether or not the changeover switch 22C is tilted counterclockwise on the paper surface of FIG. 1 to be in the second state. The determination is made based on whether or not an inverted signal is output from the forward / reverse signal output unit 22D.

When it is determined in step S101 that the changeover switch 22C is not in the second state (step 101: No), that is, when it is determined that the changeover switch 22C is in the first state, the microcomputer 10 refers to the trigger switch 22A in step S102. To determine whether the pull operation is being performed. Specifically, it is determined whether or not the trigger switch 22A is currently in the ON state. In other words, the microcomputer 10 determines whether or not an on operation for switching the trigger switch 22A from the off state to the on state has been performed. The determination is made based on whether or not the tool start signal is output from the start signal output unit 22B.

If it is determined in step S102 that the trigger switch 22A is not in the ON state (step S102: No), that is, if it is determined that the trigger switch 22A is in the OFF state, the microcomputer 10 repeats the determination process in step S102. That is, in step S102, the microcomputer 10 continuously monitors the state of the trigger switch 22A. On the other hand, when it is determined in step S102 that the trigger switch 22A is in the ON state (step S102: Yes), the microcomputer 10 starts the drive control of the motor 3 in step S103.

In step S104, the microcomputer 10 determines whether or not the pulling operation on the trigger switch 22A has been released. Specifically, it is determined whether or not the trigger switch 22A is currently in the off state. In other words, the microcomputer 10 determines whether or not an off operation for switching the trigger switch 22A from the on state to the off state has been performed. When the output of the start signal from the start signal output unit 22B is stopped, the microcomputer 10 determines that the trigger switch 22A is in the off state.

If it is determined in step S104 that the trigger switch 22A is not in the off state (step S104: No), the microcomputer 10 repeats the process of step S104. That is, in step S104, the microcomputer 10 continuously monitors the state of the trigger switch 22A. On the other hand, when it is determined in step S104 that the trigger switch 22A is in the off state (step S104: Yes), the microcomputer 10 stops driving the motor 3 in step S105. After that, unless the changeover switch 22C is switched to the second state, the microcomputer 10 repeats the processes from step S101 to step S105.

On the other hand, when it is determined in step S101 that the changeover switch 22C is in the second state (step S101: Yes), the microcomputer 10 determines in step S106 whether or not the trigger switch 22A is currently in the ON state. ..

If it is determined in step S106 that the trigger switch 22A is not in the ON state (step S106: No), the microcomputer 10 repeats the process of step S106. That is, in step S106, the microcomputer 10 continuously monitors the state of the trigger switch 22A. On the other hand, when it is determined in step S106 that the trigger switch 22A is in the ON state (step S106: Yes), the microcomputer 10 starts the drive control of the motor 3 in step S107.

In step S108, the microcomputer 10 determines whether or not the trigger switch 22A is currently in the off state. If it is determined in step S108 that the trigger switch 22A is not in the off state (step S108: No), the microcomputer 10 repeats the process of step S108. That is, in step S108, the microcomputer 10 continuously monitors the state of the trigger switch 22A. On the other hand, when it is determined in step S108 that the trigger switch 22A is in the off state (step S108: Yes), the microcomputer 10 stops driving the motor 3 (step S109).

After that, in step S110, the microcomputer 10 determines whether or not the period from the time when the trigger switch 22A is turned on in step S106 to the time when the trigger switch 22A is turned off in step S108 exceeds 400 ms. To do. Specifically, in the present embodiment, the microcomputer 10 measures the elapsed time from the time when the tool start signal from the start signal output unit 22B is received in step S106 by its timer counter function. In the following description, the elapsed time at the time of determination in step S110 is referred to as TA. Then, by comparing the TA with the threshold value stored in the ROM in advance, it is determined whether or not the TA exceeds 400 ms. In the present embodiment, 400 ms is used as the threshold value, but a longer period or a shorter period may be used as the threshold value.

When it is determined in step S110 that the TA exceeds the threshold value of 400 ms (step S110: No), the microcomputer 10 performs the processes of step S101 and steps S106 to S110 unless the changeover switch 22C is switched to the first state. Repeat.

When it is determined in step S110 that the TA does not exceed the threshold value of 400 ms (step S110: Yes), the microcomputer 10 determines in step S111 whether or not the trigger switch 22A is in the ON state.

If it is determined in step S111 that the trigger switch 22A is not in the ON state (step S111: No), the microcomputer 10 repeats the processes of step S110 and step S111. That is, the microcomputer 10 continuously monitors the state of the trigger switch 22A until the TA exceeds the threshold value of 400 ms.

When it is determined in step S111 that the trigger switch 22A is not in the ON state (step S111: Yes), the microcomputer 10 determines that the trigger switch 22A is not in the ON state in step S112 from the time when the trigger switch 22A is turned on in step S106. It is determined whether or not the period until the time when is turned on again exceeds the threshold value of 400 ms. Specifically, it is determined whether or not the TB exceeds 400 ms by comparing the elapsed time TB at the time of determination in step S112 with the threshold value stored in advance in the ROM. The operation of turning on the trigger switch in steps S106 and S112 is an example of the "predetermined operation" in the present invention.

If it is determined in step S112 that TB exceeds the threshold value of 400 ms (step S112: No), the microcomputer 10 performs the processes of step S101 and steps S106 to S112 unless the changeover switch 22C is switched to the first state. Repeat.

When it is determined in step S112 that TB does not exceed the threshold value 400 ms (step S112: Yes), the microcomputer 10 shifts the operation mode of the screw tightening machine 1 to the “on-lock mode” in step S113. In this state, even if the operator releases the trigger switch 22A and the trigger switch 22A shifts to the off state, the control unit 4 continues the drive control of the motor 3.

In step S114, the microcomputer 10 determines whether or not the trigger switch 22A is in the off state. When it is determined in step S114 that the trigger switch 22A is not in the off state (step S114: No), the microcomputer 10 continuously monitors the state of the trigger switch 22A. On the other hand, when it is determined in step S114 that the trigger switch 22A is in the off state (step S114: Yes), the microcomputer 10 determines in step S115 whether or not the trigger switch 22A is in the on state.

When it is determined in step S115 that the trigger switch 22A is not in the ON state (step S115: No), the microcomputer 10 continuously monitors the state of the trigger switch 22A. On the other hand, when it is determined in step S115 that the trigger switch 22A is in the ON state (step S115: Yes), the microcomputer 10 releases the on-lock mode. Specifically, the microcomputer 10 shifts the operation mode of the screw tightening machine 1 from the on-lock mode to the normal mode, and stops the driving of the motor 3. After that, unless the changeover switch 22C is switched to the first state, the microcomputer 10 repeats the processes of step S101 and steps S106 to S116.

As described above, in the present embodiment, when the operation mode of the screw tightening machine 1 is the normal mode, when the microcomputer 10 controls the rotation shaft 31 of the motor 3 to rotate in the reverse direction (that is,). (When the output shaft portion 6 rotates in the normal direction), the microcomputer 10 is configured to be able to switch the operation mode of the screw tightening machine 1 from the normal mode to the on-lock mode. Therefore, it is possible to omit the operation of starting the motor 3 for each work by the operator, and the operability and workability are improved. The microcomputer 10 is an example of the "control unit" in the present invention.

Further, when the microcomputer 10 controls the rotation shaft 31 of the motor 3 to rotate in the forward rotation direction (that is, when the output shaft portion 6 is inverted), the microcomputer 10 normally sets the operation mode of the screw tightening machine 1. It is configured to stay in mode. According to such a configuration, as in the present embodiment, by using the one-way clutch 51C, the pressing force of the tip tool P against the fastener is mediated when the output shaft portion 6 is reversed (when the motor 3 is rotated forward). In the configuration in which the driving force of the motor 3 is transmitted to the output shaft portion 6 without it, the on-lock mode is not unintentionally shifted. As a result, the tip tool P can be suitably engaged with a fastener (for example, a screw or the like), and operability and workability can be improved.

Further, in the present embodiment, when the forward / reverse signal output unit 22D outputs an inverted signal, the operator performs an on operation for switching the trigger switch 22A from the off state to the on state twice in 400 ms. It is possible to switch the operation mode of the screw tightening machine 1 from the normal mode to the on-lock mode. Since it is possible to shift to the on-lock mode by such a simple operation, operability and workability can be improved. Further, when switching the mode of the screw tightening machine 1 from the normal mode to the on-lock mode, it is not necessary for the operator to change hands, and the operability and workability are improved. Further, it is not necessary to provide other members and mechanisms for switching the operation mode, and the number of parts can be reduced. In the present embodiment, the mode is switched by performing the ON operation on the trigger switch 22A twice in 400 ms, but the configuration is not necessarily limited to such a configuration. For example, the number of on operations may be 3 or more.

Further, when the trigger switch 22A is turned on while the screw tightening machine 1 is operating in the on-lock mode, the microcomputer 10 can release the state in which the screw tightening machine 1 is operating in the on-lock mode. Is. Therefore, it is not necessary for the operator to change hands, and the operability and workability are improved. Further, since the on-lock mode can be released by a simple operation, operability and workability are improved. Further, it is not necessary to provide other members and mechanisms to release the on-lock mode, and the number of parts can be reduced.

In the present embodiment, the on-lock mode is released when the operator performs the on operation, but the configuration is not necessarily limited to such a configuration. For example, the on-lock mode may be released when the trigger switch 22A is turned on and off. According to such a configuration, the screw tightening machine 1 responds to a series of operations of shifting the trigger switch 22A from the off state to the on state (on operation) and then shifting to the off state again (off operation). Since the state of operating in the on-lock mode can be released, operability and workability are improved.

Next, a first modification of the above-described embodiment will be described. In the above embodiment, the mode is switched according to the operation of the trigger switch 22A a plurality of times within a predetermined time, whereas in this modification, the trigger switch 22A is kept on for a predetermined time or longer. The mode is switched depending on whether or not the operation has been performed. Since the processes from steps S101 to S107 are the same as those in the above embodiment, the description thereof will be omitted.

In step S208, the microcomputer 10 determines whether or not the trigger switch 22A is currently in the off state. If it is determined in step S208 that the trigger switch 22A is not in the off state (step S208: No), the microcomputer 10 repeats the process of step S208. That is, the microcomputer 10 continuously monitors the state of the trigger switch 22A in step S208. On the other hand, when it is determined in step S208 that the trigger switch 22A is in the off state (step S208: Yes), the microcomputer 10 triggers in step S209 from the time when the trigger switch 22A is turned on in step S106. It is determined whether or not the period until the time when the switch 22A is turned off exceeds 500 ms. Specifically, it is determined whether or not T exceeds 500 ms by comparing the elapsed time T at the time of determination in step S209 with the threshold value stored in advance in the ROM. In this modification, 500 ms is used as the threshold value, but a longer time or a shorter time may be used as the threshold value.

When it is determined in step S209 that T does not exceed the threshold value of 500 ms (step S209: No), the microcomputer 10 stops driving the motor 3 (step S105). On the other hand, when it is determined in step S209 that T exceeds 500 ms (step S209: Yes), the microcomputer 10 shifts the mode of the screw tightening machine 1 to the on-lock mode in step S210. Even with such a configuration, the same effect as that of the above-described embodiment can be obtained. Since steps S211 and S212 are steps for releasing the on-lock mode, which are the same as steps S115 and S116 in the above-described embodiment, the description thereof will be omitted.

Next, a second modification of the above-described embodiment will be described. In the above embodiment, the mode is switched according to the operation of the trigger switch 22A a plurality of times within a predetermined time, whereas in this modification, the trigger switch 22A is kept on for a predetermined time or longer. The mode is switched depending on whether or not the operation has been performed. Since the processes from steps S101 to S107 are the same as those in the above embodiment, the description thereof will be omitted.

In step S308, the microcomputer 10 determines whether or not the trigger switch 22A is currently in the off state. If it is determined in step S308 that the trigger switch 22A is not in the off state (step S308: No), the microcomputer 10 repeats the process of step S308. That is, the microcomputer 10 continuously monitors the state of the trigger switch 22A in step S308. On the other hand, when it is determined in step S308 that the trigger switch 22A is in the off state (step S308: Yes), the microcomputer 10 triggers in step S309 from the time when the trigger switch 22A is turned on in step S106. It is determined whether or not the elapsed time T until the time when the switch 22A is turned off exceeds 500 ms. In this modification, 500 ms is used as the threshold value, but a longer time or a shorter time may be used.

If it is determined in step S309 that T does not exceed the threshold value of 500 ms (step S309: No), the microcomputer 10 stops driving the motor 3 (step S105). On the other hand, when it is determined in step S309 that T exceeds 500 ms (step S309: Yes), the microcomputer 10 performs the trigger switch in step S310 from the time when the trigger switch 22A is turned on in step S106. It is determined whether or not the elapsed time T until the time when 22A is turned off exceeds 3s. In this modification, if the threshold value is longer than 500 ms, a time longer or shorter than 3 s may be used.

When it is determined in step S310 that T exceeds 3 s (step S310: No), the microcomputer 10 stops driving the motor 3. On the other hand, when it is determined in step S310 that T does not exceed 3s (step S310: Yes), the microcomputer 10 shifts the mode of the screw tightening machine 1 to the on-lock mode in step S311. Even with such a configuration, the same effect as that of the above-described embodiment can be obtained. Further, by setting the double threshold value of 500 ms and 3 s, it is possible to preferably shift to the on-lock mode according to the intention of the operator. Since step S312 and step S313 are steps for releasing the on-lock mode, which are the same as steps S115 and S116 in the above-described embodiment, the description thereof will be omitted.

Next, the control of the screw tightening machine according to the second embodiment of the present invention will be described with reference to FIGS. 6 to 8. The screw tightening machine according to the second embodiment has the same configuration as the screw tightening machine 1 according to the first embodiment, and only the control by the control unit 4 is different from the screw tightening machine 1. Further, in the present embodiment, the ROM or RAM of the microcomputer 10 is configured to store the operation mode of the screw tightening machine at the time of the previous power off in the storage area thereof.

Further, in the operation mode of the screw tightening machine according to the second embodiment, as shown in FIG. 6, the first terminal 42B and the second terminal 42C (see FIG. 2) are electrically connected to the commercial AC power supply. It is configured to switch according to the state of various switches (trigger switch 22A, changeover switch 22C) and their combinations when power is supplied to the control unit 4. Specifically, pattern 1 (No. 1 in the figure) is configured to be switchable between predetermined modes when power is supplied to the control unit 4 while the trigger switch 22A is maintained in the ON state. Has been done. Hereinafter, it will be described assuming that pattern 1 is adopted as the mode switching pattern of the present embodiment with reference to FIG. 7.

When the operator inserts a plug (not shown) of the power cord 2A into the external power supply Q, the screw tightening machine 1 and the external power supply Q are electrically connected via the first terminal 42B and the second terminal 42C (see FIG. 2). Be connected. As a result, electric power is supplied to the microcomputer 10 (control unit 4), and the process shown in the flowchart of FIG. 7 is started with this as an opportunity.

When the power is supplied, the microcomputer 10 immediately determines in step S401 whether or not the trigger switch 22A is in the ON state. In other words, the microcomputer 10 determines whether or not the on state of the trigger switch 22A is maintained and the first terminal 42B and the second terminal 42C are connected to the external power supply Q. When it is determined in step S401 that the trigger switch 22A is not in the ON state (step S401: No), the microcomputer 10 holds the mode at the time of the previous power off in step S402, and the trigger switch 22A is in the ON state in step S403. Continue to monitor if it is in.

When it is determined in step S403 that the trigger switch 22A is in the ON state (step S403: Yes), the microcomputer 10 drives the motor 3 in the mode of the previous power off stored in the RAM or ROM in step S404. ..

In step S405, the microcomputer 10 determines whether or not the trigger switch 22A is currently in the off state. If it is determined in step S405 that the trigger switch 22A is not in the off state (step S405: No), the microcomputer 10 continues to drive the motor 3. On the other hand, when it is determined in step S405 that the trigger switch 22A is in the off state (step S405: Yes), the microcomputer 10 stops driving the motor 3. At this time, the microcomputer 10 holds the state in which the mode at the time of the previous power off is stored (step S406).

On the other hand, when it is determined in step S401 that the trigger switch 22A is in the ON state (step S401: Yes), the microcomputer 10 does not drive the motor 3 in the ON operation of the trigger switch 22A in step S401 in step S407. stand by. At the same time, the microcomputer 10 switches the operation mode of the screw tightening machine in step S408. Further, the ROM or RAM of the microcomputer 10 stores the changed operation mode of the screw tightening machine in the storage area.

In step S409, the microcomputer 10 determines whether or not the trigger switch 22A is currently in the off state. If it is determined in step S409 that the trigger switch 22A is not in the off state (step S409: No), the microcomputer 10 repeats the process of step S409. On the other hand, when it is determined in step S409 that the trigger switch 22A is in the off state (step S410: Yes), the microcomputer 10 determines in step S410 whether or not the trigger switch 22A is in the on state at the present time.

When it is determined in step S410 that the trigger switch 22A is in the ON state (step S410: Yes), the microcomputer 10 drives the motor in the operation mode after the mode change (step S411).

In step S412, the microcomputer 10 determines whether or not the trigger switch 22A is currently in the off state. If it is determined in step S412 that the trigger switch 22A is not in the off state (step S412: No), the microcomputer 10 continues to drive the motor 3. On the other hand, when it is determined in step S412 that the trigger switch 22A is in the off state (step S412: Yes), the microcomputer 10 stops driving the motor 3. At this time, the microcomputer 10 holds the state in which the changed mode is stored (step S413).

As described above, in the present embodiment, the microcomputer 10 operates the screw tightening machine when the trigger switch 22A is maintained in the ON state and the first terminal 42B and the second terminal 42C are connected to the external power supply Q. To switch. That is, the screw tightening machine can be operated in a specific operation mode by a combination of the operation of connecting the connection portion of the screw tightening machine to the external power supply Q and the operation of the trigger switch 22A, which are normally performed by the operator during the work. Therefore, operability and workability are improved. Further, it is not necessary to provide other members and mechanisms for switching the operation mode of the screw tightening machine, and the number of parts can be reduced.

Further, in the second embodiment, the control unit 4 is predetermined when the on operation of the trigger switch 22A is maintained and the first terminal 42B and the second terminal 42C are connected to the external power supply Q (see step S401 above). The operation mode of the screw tightening machine can be switched to the on-lock mode when the operation of the above is performed on the trigger switch 22A and the control unit 4 controls the rotating shaft 31 of the motor 3 to rotate in the reverse direction. A permitted state and a disallowed state in which the operation mode of the screw tightening machine is maintained in the normal mode even when a predetermined operation is performed on the operation unit and the control unit 4 controls the rotation shaft 31 to rotate in the reverse direction. It may be configured to be switchable between. According to such a configuration, when the operator thinks that it is unnecessary to switch the operation mode of the screw tightening machine from the normal mode to the on-lock mode, the first terminal 42B and the second terminal 42C of the screw tightening machine are externally connected. Operability and workability are improved because the screw tightener can be operated in a specific operation mode by a combination of operations and operations normally performed by an operator during work, such as an operation of connecting to the power supply Q and an operation of the trigger switch 22A. To do.

In the present embodiment, the screw tightening machine is configured to operate by being electrically connected to the external power supply Q, but is configured to operate by being electrically connected to the battery pack. It may have been done. Even when the battery pack is used, when the operator attaches the battery pack to the screw tightening machine while pulling the trigger switch 22A (when the connection part of the screw tightening machine and the connection part of the battery pack are electrically connected). ), It is possible to obtain the same effect as described above by changing the operation mode of the screw tightening machine.

Next, a modified example of the above-mentioned second embodiment will be described. This modification corresponds to pattern 3 in FIG. 6, and when power is supplied to the control unit 4 when the trigger switch 22A is maintained in the ON state and the changeover switch 22C is in the second state, between predetermined modes. It is configured to be switchable with.

First, since the processes from step S501 to step S507 are the same as steps S401 to S407 in the above-described embodiment, the description thereof will be omitted.

In step S508, the microcomputer 10 determines whether or not the state of the changeover switch 22C is the second state. When it is determined in step S508 that the changeover switch 22C is not in the second state (step S508: No), the microcomputer 10 performs the processes of steps S502 to S506. On the other hand, when it is determined in step S508 that the changeover switch 22C is in the second state (step S508: Yes), the microcomputer 10 switches the operation mode of the screw tightener in step S509. Further, the ROM or RAM of the microcomputer 10 stores the changed operation mode of the screw tightening machine in the storage area. Since the processes from step S510 to step S514 are the same as steps S409 to S413 in the above-described embodiment, the description thereof will be omitted.

As described above, in this modification, the operator of connecting the first terminal 42B and the second terminal 42C of the screw tightening machine to the external power supply Q, operating the changeover switch 22C, and operating the trigger switch 22A is usually performed during work. Since the screw tightening machine can be operated in a specific operation mode depending on the combination of the work to be performed and the operation, the operability and workability are improved. Further, it is not necessary to provide other members and mechanisms for switching the operation mode of the screw tightening machine, and the number of parts can be reduced. Further, since the mode is switched under the two conditions of the pull operation to the trigger switch 22A and the state of the changeover switch 22C, the mode change unintentional by the operator is suppressed and the operability is suppressed as compared with the case where only one condition is provided. And workability is improved.

The mode switching pattern is not limited to the above-mentioned switching pattern. For example, as shown in pattern 2 of FIG. 6, when power is supplied to the control unit 4 when the trigger switch 22A is maintained in the ON state and the changeover switch 22C is in the first state, between predetermined modes. It may be configured to be switchable to. Further, for example, as shown in pattern 4, when power is supplied to the control unit 4 when the trigger switch 22A is maintained in the ON state and the changeover switch 22C is in the first state, the screw tightening machine is predetermined. It may be configured so that the state of operating in mode A is forcibly realized. That is, in pattern 4, if the operation mode at the time of the previous power off was not mode A, the operation mode is forcibly switched to the state in which the mode A can be operated, and the operation mode at the time of the previous power off is mode A. If so, the state in which the mode A can be operated is maintained. Further, for example, as shown in pattern 5, when the trigger switch 22A is maintained in the ON state and the changeover switch 22C is in the second state, when power is supplied to the control unit, the screw tightening machine is set to a predetermined mode. It may be configured so that the state of operating in B is forcibly realized.

In the present embodiment, the screw tightening machine 1 has been described as an example of the electric tool, but the present invention describes an electric tool driven by a motor other than the screw tightening machine, for example, a drilling work machine such as a hammer or a hammer drill. It can also be applied to cutting tools such as jigsaws and saver saws, and power tools such as hammers. For example, when the present invention is applied to a nailing machine, it is possible to improve operability and workability in switching between a single-shot mode and a continuous-shot mode. Further, the operation mode of the power tool is not limited to the operation mode shown above, and the present invention can improve the operability and workability in switching the mode related to the lighting of the light. Specifically, the lighting mode of the light (mode of blinking continuously for a predetermined time, mode of blinking in synchronization with the rotation of the output shaft, etc.) may be switched.

1 ... Screw tightening machine 2 ... Housing 3 ... Motor 4 ... Control unit 5 ... Clutch unit 6 ... Output shaft unit

Claims (11)

A motor having a rotating shaft that rotates in the first and second directions,
The output shaft, which is removable from the tip tool and is driven by the driving force of the motor,
An electric tool having a control unit that controls the rotation direction of the rotation shaft so as to be switchable between the first direction and the second direction.
The control unit
By controlling the motor, the operation mode can be switched between a plurality of operation modes including the first mode and the second mode.
In the case of the first mode, when the control unit controls the rotation axis to rotate in the first direction, the first mode can be switched to the second mode.
A power tool characterized in that when the control unit controls the rotation axis to rotate in the second direction, the control unit maintains the first mode. It can be switched between an on state and an off state, and further has an operation unit for controlling the start and stop of the motor.
The control unit
When a predetermined operation for switching from the first mode to the second mode is performed on the operation unit and the control unit controls the rotation axis to rotate in the first direction, the first operation is performed. The power tool according to claim 1, wherein the mode is switched from the first mode to the second mode. The power tool according to claim 2, wherein the predetermined operation is an operation of performing an on operation for switching the operation unit from an off state to an on state a predetermined number of times within a predetermined time. When the on operation is performed on the operation unit while the motor is being driven while the operation mode is the second mode, the control unit releases the state of operating in the second mode. The power tool according to claim 3. When the on operation is performed on the operation unit and the off operation for switching the operation unit from the on state to the off state is performed while the motor is being driven in the state where the operation mode is the second mode. The power tool according to claim 3, wherein the control unit releases the state of operating in the second mode. It also has a connection that is electrically connected to an external power source
A third to fifth aspect of the present invention, wherein the control unit switches between the first mode and the second mode when the on state is maintained and the connection unit is electrically connected to the external power source. The power tool according to any one of the above. It also has a connection that is electrically connected to an external power source
When the control unit is maintained in the ON state and the connection unit is electrically connected to the external power supply, the predetermined operation is performed on the operation unit, and the control unit connects the rotation shaft to the first. A permission state in which the first mode can be switched to the second mode when controlled to rotate in one direction, and the predetermined operation is performed on the operation unit, and the control unit controls the rotation axis. The electric motor according to any one of claims 3 to 5, wherein the electric power is switched between the disallowed state for maintaining the first mode even when the control is performed so as to rotate in the first direction. tool. Connections that are electrically connected to an external power source
Further, it has a changeover switch configured to be able to change the rotation direction of the motor.
3. The control unit is characterized in that when the connection unit is electrically connected to the external power supply, the control unit switches between the first mode and the second mode according to the state of the changeover switch. The power tool according to any one of 5 to 5. Connections that are electrically connected to an external power source
Further, it has a changeover switch configured to be able to change the rotation direction of the motor.
The changeover switch is configured to be switchable between a first state for making the rotation direction of the motor the first direction and a second state for making the rotation direction the second direction.
In the control unit, when the changeover switch is in the first state and the connection unit is electrically connected to the external power supply, the predetermined operation is performed on the operation unit and the control unit performs the control unit. A permission state in which the first mode can be switched to the second mode when the rotation axis is controlled to rotate in the first direction, and the predetermined operation is performed on the operation unit and the control unit Any one of claims 3 to 5, wherein even when the rotation axis is controlled to rotate in the first direction, the rotation axis is switched between the disallowed state for maintaining the first mode. Power tools described in the section. A motor with a rotating shaft and
The output shaft, which is removable from the tip tool and is driven by the driving force of the motor,
An operation unit that can be switched between an on state and an off state and controls the start and stop of the motor,
Connections that are electrically connected to an external power source
An electric tool having a control unit for controlling the motor.
The control unit
By controlling the motor, it is possible to switch between a plurality of operation modes including the first mode and the second mode.
A power tool characterized by switching between the first mode and the second mode when the on state is maintained and the connection portion is electrically connected to the external power source. A motor having a rotating shaft that rotates in the first and second directions,
The output shaft, which is removable from the tip tool and is driven by the driving force of the motor,
Connections that are electrically connected to an external power source
A control unit that controls the rotation direction of the motor so as to be switchable between the first direction and the second direction.
An electric tool having a changeover switch configured to switch the rotation direction of the motor.
The control unit
By controlling the motor, it is possible to switch between a plurality of operation modes including the first mode and the second mode.
A power tool characterized in that when the connection portion is electrically connected to the external power source, it is switched between the first mode and the second mode according to the state of the changeover switch.

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