Matsushita Electric Works, Ltd.

Yosuke Ishida

Koichi Hashimoto

Hidenori Shimizu

Hiroshi Miyazaki

Atsumasa Kubota

Tomio Yamada

Masao Yamamoto

Ichiro Kishi

Kazuto Toyama

Akihiro Ishibashi

Toru Murakita

Natsuhara Tsutomu

A portable motor powered device capable of operating on a cordless battery pack as well as a corded power pack, yet enabling to reduce the size and weight of the corded power pack to be truly compatible with the corded battery pack in size and weight. The device has a housing accommodating therein a DC motor as a power source. The cordless battery pack is detachably connected to the housing and has a battery which supplies a low DC voltage for operating the DC motor. The corded power pack is detachably connected to the housing and supplies a high DC voltage for operating the DC motor. The corded power pack includes a power cord adapted to be connected to receive an AC source voltage and a converter for converting the AC source voltage into the high DC voltage. The DC motor has a rotor provided with first and second windings which are selectively connected to receive low and high DC voltages respectively from the cordless battery pack and the corded power pack. Thus, the corded power pack can be designed to supply the high DC voltage directly converted from the AC voltage source and therefore dispense with a step-down transformer of bulky and heavy nature.

Portable motor powered device

A motor-driven tool is provided with a grip on which a switch is placed, and the grip is coupled to the middle of a cylindrical housing which houses a motor in its rear end and a motor output decelerator in front of the motor in its front end. A deceleration rotation output shaft is provided in the front of the housing. The motor houses an axial flow fan for air intake in the rear and a centrifugal fan for exhaust in the front and has intake air openings in the rear side and an exhaust air opening in a front side surface. The cylindrical housing also has an intake opening that connects to the intake air opening in the rear side of the motor and an exhaust opening that connects to the motor exhaust air opening at the position where the front of the motor is located. The exhaust opening of the housing may be directed upwardly and away from the tool grip, and the connection between a lead wire from the switch and the motor may be positioned adjacent either the intake air opening or the exhaust opening for effective cooling of the terminal. Additionally, an end plate of the motor, formed of a good heat conducting material, can close off the end surface of the motor, and thus may also serve as a radiator plate for a switching element positioned thereon, and the number of parts can be reduced because an independent radiator plate becomes unnecessary. A cooling vent opening may be provided in the end plate, and the cooling efficiency of the motor can be improved. Further, a mounting plate for attaching the decelerator may be mounted integrally with the end plate, and a separate mounting plate becomes unnecessary.

Motor-driven tools

A planetary transmission has a plurality of axially arranged planetary gear units each including sun gears, planet gears in mesh with the sun gears, and ring gears coaxial with the sun gears and in mesh with the planet gears, the arrangement being such that one of the ring gears in each planetary gear unit is blocked from being rotated while the other ring gear is made rotatable for allowing an output to be taken out, upon which the ring gear of which rotation is blocked is made selectable for changing over the reduction ratio, and a smooth bilateral change-over of speed change can be realized by executing the change-over between rotation-blocked and rotation-free states of the ring gear by means of a one-way clutch capable of releasing the rotation blocking.

Planetary transmission with releaseable one way clutch

A planetary gear transmission gear system comprises a main planetary gear train composed of a main sun gear, a main ring gear, and main planet gears. The main sun gear is driven by an input rotary shaft to rotate. A sub planetary gear train is included to have a sub sun gear, a sub ring gear, and sub planet gears, and has a different gear ratio from the main planetary gear train. The sub sun gear is connected to rotate together with the main sun gear. A common carrier supporting the main and sub planet gears is rotatable about a common center axis and is drivingly connected to rotate an output shaft. A lock mechanism releasably fixes the main ring gear in order to allow the main planet gears to rotate about the center axis as the main sun gear rotates with the main ring gear fixed. A one-way clutch is connected to permit the sub ring gear to rotate in a first direction and to prohibit the sub ring gear from rotating in a second direction opposite to the first direction. The first direction is selected to be a direction in which the sub ring gear is permitted to rotate while the carrier rotates with the main ring gear fixed by the lock mechanism such that the sub ring gear is locked in the second direction after the main ring gear is released, thereby permitting the carrier to continue rotating at a speed reduction ratio different than when the main ring gear is fixed.

Planetary gear transmission system

Growing community of inventors

Yasu-gun, Japan

Yosuke Ishida