Centrifugal clutch with radially movable magnetic member

Abstract

An actuator with a positive centrifugal clutch has a clutch drum loosely rotated relative to a rotary drive shaft and is provided with large inner diameter portions and engaging protuberances inwardly projecting from the large inner diameter portions; a clutch body loosely fitted within the clutch drum and driven by the rotary drive shaft, and provided with a retaining hole opening radially from the center thereof toward the inner wall of the clutch drum; and an engaging permanent magnet loosely movably retained in the retaining hole of the clutch body. When the clutch body is in a standstill state, the engaging permanent magnet provides a magnetic attraction between itself and the rotary drive shaft and thereby is accommodated within the retaining hole. When the clutch body continues its rotation, centrifugal force is generated. The centrifugal force causes the engaging permanent magnet to protrude from the retaining hole, come into contact with and slide on the inner wall of the clutch drum and engage with one of the engaging protuberances of the clutch drum. The actuator has an outer casing having a cover plate. The clutch drum has a bevel gear and an axial projection formed integrally at a rear wall of the clutch drum. The axial projection is supported by the cover plate. A lid member is also provided at one end of the drum which is loosely rotatably mounted around the rotary drive shaft and which tightly seals the one end of the drum so as to block entrance of water and dust into the clutch.