Motor-driven tools

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.

Abstract

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.

1. Drawings

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[0010]Sheet 10.