Patent ID: 7866227

Claim:
A vehicular power transmission system comprising: a transmission, the transmission having a first shifting part and a second shifting part which shift a power of an engine; a first shift clutch transmitting and interrupting the power to the first shifting part; and a second shift clutch transmitting and interrupting the power to the second shifting part, in which the first shift clutch and the second shift clutch shift gear steps of the first shifting part and gear steps of the second shifting part, the vehicular power transmission system further comprising: a start clutch transmitting and interrupting the power to the first shift clutch and the second shift clutch, the start clutch being a centrifugal clutch having a centrifugal weight controlling an intermittent state by a centrifugal force in accordance with an engine rotational speed, wherein a driven gear of the transmission mechanism transmitting the power from the centrifugal clutch to the first shift clutch and the second shift clutch is arranged between the first shift clutch and the second shift clutch in an axial direction, wherein the first shift clutch and the second shift clutch are constructed of hydraulic clutches having hydraulic chambers and are arranged back to back so that the hydraulic chamber of the first shift clutch and the hydraulic chamber of the second shift clutch are close to each other in the axial direction, and wherein the first shift clutch is disposed in a position that is directly adjacent to the centrifugal clutch.