Abstract: An electric working machine in one aspect of the present disclosure includes an output shaft, a motor, a housing, an acceleration detector, a twisted motion detector, a reference level changer, and a motor controller. The acceleration detector detects an acceleration of the housing in a circumferential direction of the output shaft. The twisted motion detector detects a twisted motion of the housing based on a reference level and the acceleration detected. The reference level determines that the housing is twisted. The reference level changer changes the reference level based on a rotating motion of the output shaft.

Abstract: A rotary impact tool in one aspect of the present disclosure includes a motor, an impact mechanism, an impact detector, and a controller. The controller executes constant duty ratio control from when the motor is started until an impact is detected by the impact detector. The controller executes constant rotation speed control in response to detection of an impact by the impact detector.

Abstract: An impact fastening tool may include a motor; a hammer configured to be rotationally driven by the motor; an anvil configured to be hit in a rotational direction by the hammer; a signal obtainer configured to obtain a variable signal which varies in accordance with a hit to the anvil by the hammer; and a seating determiner configured to determine whether or not a fastener has been seated based on the variable signal obtained by the signal obtainer, wherein the seating determiner is configured to determine whether or not the fastener has been seated based on a signal component of the variable signal obtained by the signal obtainer, the signal component corresponding to a predetermined reference frequency.

Abstract: An electric power tool is configured to rotate an attachment about a Z-axis. The electric power tool includes a three-axes acceleration sensor and an acceleration detection circuit. The acceleration detection circuit calculates an angular acceleration about the Z-axis based on an input signal from the three-axes acceleration sensor. The acceleration detection circuit calculates a change in an angular velocity based on integrating the angular acceleration for a most recent period. The acceleration detection circuit determines a Z-axis angular velocity about the Z-axis, without adding a previous change in the angular velocity from before the most recent period, as equal to the change in angular velocity. The acceleration detection circuit detects a twisted-motion of the electric power tool based on the Z-axis angular velocity.

Abstract: An electric working machine in one aspect of the present disclosure includes an output shaft, a motor, a housing, an acceleration detector, a twisted motion detector, a reference level changer, and a motor controller. The acceleration detector detects an acceleration of the housing in a circumferential direction of the output shaft. The twisted motion detector detects a twisted motion of the housing based on a reference level and the acceleration detected. The reference level determines that the housing is twisted. The reference level changer changes the reference level based on a rotating motion of the output shaft.

Abstract: A rotary impact tool in one aspect of the present disclosure includes a motor, an impact mechanism, an impact detector, and a controller. The controller executes constant duty ratio control from when the motor is started until an impact is detected by the impact detector. The controller executes constant rotation speed control in response to detection of an impact by the impact detector.

Abstract: An impact fastening tool may include a motor; a hammer configured to be rotationally driven by the motor; an anvil configured to he hit in a rotational direction by the hammer; a signal obtainer configured to obtain a variable signal. which varies in accordance with a hit to the anvil by the hammer; and a seating determiner configured to determine whether or not a fastener has been seated based on the variable signal obtained by the signal obtainer, wherein the seating determiner is configured to determine whether or not the fastener has been seated based on a signal component of the variable signal obtained by the signal obtainer, the signal component corresponding to a predetermined reference frequency.

Abstract: An electric power tool includes a housing, a motor, an output shaft, an acceleration sensor, and a twisted-motion detector. The housing is configured to house the motor and the output shaft. The acceleration sensor is configured to detect acceleration of the housing. The twisted-motion detector is configured to repeatedly obtain acceleration of the housing in the circumferential direction of the output shaft, to calculate a speed by integrating, of the obtained accelerations, accelerations obtained in a certain period, and to detect twisting of the housing from the speed.

Abstract: It is an object of the invention to provide a technique for enhancing the operability of a power tool. A representative screwdriver 100 is provided which has a motor 110 and a driving mechanism 120. The driving mechanism 120 has a rotation transmitting mechanism including a driving cam 137 and a driven cam 157, and a cam engagement state is switched by movement of the spindle 150 in a longitudinal direction of the spindle. The position of the spindle 150 in the longitudinal direction is detected by a detecting mechanism 162 that is disposed on the opposite side of the rotation transmitting mechanism from a front end region in the longitudinal direction of the spindle 150. A controller 180 controls the rotation speed of the motor 110 based on the detection result of the detecting mechanism 162 and drives the motor 110.

Abstract: The present application discloses an apparatus including: a motor model that reflects a characteristic of a motor and includes at least inputs pertaining to a first quantity of state and a second quantity of state and an output pertaining to a third quantity of state; a comparator that calculates a difference between the third quantity of state in an actual motor and the third quantity of state output from the motor model; and an amplifier that amplifies an output of the comparator at a predetermined gain. The first quantity of state in the actual motor is input into the motor model as the first quantity of state, and an output of the amplifier is input into the motor model as the second quantity of state. The apparatus then uses the output of the amplifier as an estimated value of the second quantity of state in the actual motor.

Abstract: A reciprocating electric power tool in one aspect of the present invention includes an attachment unit, a motor, a power transmission unit, and a controller. The controller is configured to operate the motor at a first speed when activated; to operate the motor at a second speed that is higher than the first speed when a first condition is satisfied after activation; and, to operate the motor at a third speed that is higher than the second speed when a second condition is satisfied after the first condition is satisfied.

Abstract: A power tool comprises a motor, an output torque calculation unit configured to calculate an output torque of the motor based on a current flowing through the motor, a friction torque calculation unit configured to calculate a friction torque of the motor based on a rotation speed of the motor, a load torque estimation unit configured to estimate a load torque acting on the motor, an inertia torque calculation unit configured to calculate an inertia torque based on the output torque, the friction torque and the load torque, and a motor deceleration unit configured to stop or decelerate the motor when the inertia torque is greater than an inertia torque reference value.

Abstract: It is an object of the invention to provide a technique for enhancing the operability of a power tool. A representative screwdriver 100 is provided which has a motor 110 and a driving mechanism 120. The driving mechanism 120 has a rotation transmitting mechanism including a driving cam 137 and a driven cam 157, and a cam engagement state is switched by movement of the spindle 150 in a longitudinal direction of the spindle. The position of the spindle 150 in the longitudinal direction is detected by a detecting mechanism 162 that is disposed on the opposite side of the rotation transmitting mechanism from a front end region in the longitudinal direction of the spindle 150. A controller 180 controls the rotation speed of the motor 110 based on the detection result of the detecting mechanism 162 and drives the motor 110.

Abstract: An improved hand-held power tool is provided which can effectively reduce whirling vibration caused by imbalance of a rotating element. The power tool has a grip that is connected to a tool body and designed to be held by a user and a self-synchronous mechanism that reduces whirling vibration caused in the tool body or the grip when the tool bit is driven. The self-synchronous mechanism is of a phase variable type, having a rotating body which serves as a vibrator and is rotationally driven by a driving source different from a driving source for the tool bit. The self-synchronous mechanism is disposed in the tool body or the grip in which whirling vibration is caused, and arranged such that a phase of vibration of the rotating body is automatically tuned to a phase of the whirling vibration, thereby reducing the whirling vibration.

Abstract: The present application discloses an apparatus including: a motor model that reflects a characteristic of a motor and includes at least inputs pertaining to a first quantity of state and a second quantity of state and an output pertaining to a third quantity of state; a comparator that calculates a difference between the third quantity of state in an actual motor and the third quantity of state output from the motor model; and an amplifier that amplifies an output of the comparator at a predetermined gain. The first quantity of state in the actual motor is input into the motor model as the first quantity of state, and an output of the amplifier is input into the motor model as the second quantity of state. The apparatus then uses the output of the amplifier as an estimated value of the second quantity of state in the actual motor.

Abstract: An improved hand-held power tool is provided which can effectively reduce whirling vibration caused by imbalance of a rotating element. The power tool has a grip that is connected to a tool body and designed to be held by a user and a self-synchronous mechanism that reduces whirling vibration caused in the tool body or the grip when the tool bit is driven. The self-synchronous mechanism is of a phase variable type, having a rotating body which serves as a vibrator and is rotationally driven by a driving source different from a driving source for the tool bit. The self-synchronous mechanism is disposed in the tool body or the grip in which whirling vibration is caused, and arranged such that a phase of vibration of the rotating body is automatically tuned to a phase of the whirling vibration, thereby reducing the whirling vibration.