PURPOSE: To lower vibration by interposing a spring member which restricts twist between both flanges to a specified value, and a vane pump with an orifice which causes the difference in revolution speed between both shafts, between an input shaft side flange and an output shaft side flange in a power transmission with a shock absorbing mechanism for an automobile and the like.

CONSTITUTION: A compression coil spring 4 is interposed between an input shaft side flange 3 and an output shaft side flange 6. A vane pump 3 is also interposed between an output shaft 5 on which the output shaft side flange 6 is fitted via a coupling 94 in such a way as to be capable of being monolithically rotated, and the input shaft side flange 3. Both the flanges 2 and 6 are connected to each other with the compression spring 4, and twist between both the flanges 2 and 6 is concurrently restricted to a specified value. In addition, each vane 34 of the vane pump 3 is moved in response to the difference in revolution speed between the input shaft 1 and the output shaft 5, oil is allowed to be moved through an orifice 34a provided for the vanes 34, and hydraulic pressure is built up in response to the difference in revolution speed, so that torque is thereby transmitted between both shafts 1 and 5.