Patent ID: 6834877
Filing Date: 2004-12-28
Classification: B62K

Abstract:
Rear suspension of a vehicle, comprising:an underframe (1), a swing arm (15) integral with the underframe and bearing a hub axle of a drive wheel (19) and a shock absorber (24) whose ends are respectively integral with underframe (1) and swing arm (15), the torque drive being transmitted to the drive wheel (19) via a chain (21) extending between an engaging sprocket (13) integral with the underframe (1) and an engaged sprocket (20) integral with the hub axle of the drive wheel (19), said chain (21) between the engaging sprocket (13) and the engaged sprocket (20) forming two strands, one tensioned upper strand (22) transmitting the torque drive to the drive wheel (19) and a lower strand (23) the underframe (1) being formed of a vertical seat tube (2), of a top tube (4) and a down tube (3), the top tube (4) and the down tube (3) being integral with a head tube (5) bearing a fork (6), the axle of the engaging sprocket (13) being positioned at the intersection between the seat tube (2) and the down tube (3) and/or the swing arm (15), and comprising means so that the upper strand (22) of the transmission chain (21) or the straight line extending the same, passes through the instantaneous center of rotation C of the swing arm (15) when the vehicle is in a position of static equilibrium, and so that said upper strand (22) of the chain (21) is positioned below the instantaneous center of rotation C of the swing arm (15) when the hub of the drive wheel (19) is positioned above its reference position Pr corresponding to the position of the hub axle of the drive wheel (19) when the vehicle is in a position of static equilibrium, characterized in that the swing arm (15) is made integral via at least two articulation means (17, 18) with the underframe (1) whose intersection of straight lines D1, D2 passing through rotation axles (17a, 17b, 18a, 18b) of each articulation means (17, 18) is positioned in the upper posterior quadrant of a point defined by a horizontal axis H and a vertical axis V converging towards the axle of the engaging sprocket (13), and in that the ends of the shock absorber (24) are respectively integral with the swing arm (15) or the articulation means (17) joining the swing arm (15) to the down tube (3) and with a hanger (25) of the down tube (3), said hanger (25) extending along the plane containing the tubes (2 to 5) of the underframe (1), said shock absorber (24) extending in front of the down tube (3) between the down tube (3) and the fork (6) bearing the front wheel (8), parallel to the latter or between the tubes (2 to 5) forming the underframe (1) along the plane containing the latter.