To prevent lowering of torque due to leak of oil, to prevent the occurrence of malfunction due to choking with contaminants, and to provide the function of a torque limiter.
A hydraulic type power transmission coupling comprises a containing hole 61 formed outside the delivery port 14 of a rotary valve 11; a weight member 62 movably contained in the containing hole 61 through a centrifugal force; a drain hole 66 to intercommunicate the containing hole 61 and the delivery port 14; and a ball 67 arranged below the weight member 62 and closing the drain hole 66 and opening the drain hole 66 when the weight member 62 is moved by a centrifugal force. This constitution prevents lowering of torque due to leak of oil and prevents the occurrence of defective operation due to choking with contaminants.
SHIMADA KAZUHISA
NAKANO HIROYUKI
