Driving power transmission device.

摘要

A driving power transmission device having a clutch provided between a first shaft (15) and a second shaft (16) relatively rotatable to each other for transmitting a driving power is provided, wherein a housing (21) to which the first shaft (15) is connected and a piston (24) provided in the housing (21) for actuating the clutch define a cylindrical space (40) in order to receive a plurality of blades (42) rotatable with the second shaft (16). High viscous fluid is filled within the cylindrical space (40) defined by the housing (21) and the piston (24). Each of the blades (42) has a convexly curved side surface (42a) and a concavely curved side surface (42b) located at opposite sides in rotational direction. When the first shaft (15) rotates faster than the second shaft, the convexly curved side surfaces (42a) of the blades (42) compulsorily displacs the high viscous fluid within the space in order to generate a pressure actuating the clutch (25) through the piston (24). In this forward torque transmission, the transmissive torque becomes relatively large. When the first shaft (15) rotates slower than the second shaft (16), the concavely curved side surfaces (42b) of the blades (42) compulsorily displace the high viscous fluid in order to generate a pressure for actuating the clutch (25). In this reverse torque transmission, the transmissive torque becomes smaller than that in the forward torque transmission.