Panasonic Corporation

Panasonic Intellectual Property Management Co., Ltd.

Matsushita Electric Works, Ltd.

Masatoshi Atsumi

Yutaka Yamada

Tadashi Arimura

Hiroyuki Kaizo

Kenichiro Inagaki

Kenichirou Inagaki

Hiroshi Matsumoto

Hidenori Shimizu

Toshio Kudo

Fumiaki Sawano

An automatic gearshift device for a power tool includes a speed reduction mechanism that decelerates and transmits a rotary power of a motor, a ring gear that slides and moves to switch a speed reduction ratio, a cam member that moves the ring gear, a rotation body rotated in cooperation with the cam member, a position detector that detects the position of the ring gear, and a controller that controls the driving of the gearshift motor based on the value generated by the position detector. An adjustment gear forming the rotation body includes a slot used as a positioning mark at a predetermined location in the rotating direction. When the slot of the adjustment gear is aligned with a predetermined device side positioning reference, the rotation body is positioned in an initial position in a relative positional relationship with the ring gear.

Automatic transmission for power tools

An electric power tool includes a motor; a speed reducer for transferring a rotational power of the motor at a reduced speed; and a reduction ratio changing unit for changing a reduction ratio of the speed reducer. The speed reduction mechanism includes an axially slidable changeover member and a gear member, the changeover member being engaged with or disengaged from the gear member depending on an axial slide position thereof. The reduction ratio changing unit includes a shift actuator for axially sliding the changeover member, a driving state detector for detecting a driving state of the motor, a slide position detector for detecting a slide position of the changeover member and a controller for driving the shift actuator and for changing a drive control of the shift actuator depending on detection results of the slide position detector unit and the driving state detector unit, respectively.

Electric power tool

An electric power tool includes a motor; a speed reducer for transferring a rotational power of the motor at a reduced speed; and a reduction ratio changing unit for changing a reduction ratio of the speed reducer. The speed reduction mechanism includes an axially slidable changeover member and a gear member, the changeover member being engaged with or disengaged from the gear member depending on an axial slide position thereof. The reduction ratio changing unit includes a shift actuator for axially sliding the changeover member, a driving state detector for detecting a driving state of the motor, a slide position detector for detecting a slide position of the changeover member and a controller for driving the shift actuator and for temporarily decreasing or increasing a rotational power of the motor depending on detection results of the driving state detector and the slide position detector, respectively.

A speed-changing device includes a motor, a reduction gear train that reduces a rotation speed of the motor in accordance with a speed reduction ratio and transmits the rotation at the reduced speed, and a speed reduction ratio switching unit that switches the speed reduction ratio. The speed reduction ratio switching unit includes an actuator that switches the speed reduction ratio, a controller that controls the actuator, and a drive state detector that detects an index value representing load torque applied to the motor. The controller activates the actuator when the index value exceeds a first threshold value and activates the actuator when the index value fluctuates between the first threshold and a second threshold thereby forming an undulated pattern that satisfies a predetermined condition.

Speed-changing device

An electric power tool includes a cylindrical reducer case accommodating the speed reduction mechanism. The speed reduction mechanism includes a planetary gear train and a movable member which is axially slidable to be engaged with or disengaged from the planetary gear train. The electric power tool includes the reducer case including a slide hole formed through a sidewall of the reducer case and axially extended and a rotary plate which is rotatable around a periphery of the reducer case about the axis, the rotary plate including an operation slot formed axially obliquely and overlapped with the slide hole; a supporting member radially outwardly protruded from the movable member and extended through the slide hole and the operation slot; and a biasing unit for applying a pressing force to the supporting member in a moving direction of the supporting member when the rotary plate is rotated to a position.

A power tool includes a power tool and a battery pack detachably attached to the power tool, the battery pack having two engaging portions to be mechanically coupled to the power tool and the power tool having engaged portions respectively corresponding to two engaging portions of the battery pack respectively. Each of engaging portions of the battery pack includes an insertion restricting portion and an attachment securing portion for allowing its corresponding engaged portion to be inserted only in a direction of pressing the attaching portion of the battery pack against the attached portion of the power tool, each of the attachment securing portions being coupled to its corresponding engaged portion. At least one of said at least two engaging portions further has a hook engaging portion which is selectively secured with an engaged portion moved from its corresponding insertion restricting portion to its corresponding attachment securing portion.

Growing community of inventors

Shiga, Japan

Masatoshi Atsumi