Base valve mechanism for shock absorber

摘要

A base valve mechanism (1, 20) of a shock absorber (D) allows oil to flow between an oil chamber (41) in the cylinder and a reservoir (44) outside the cylinder (41). By providing the base valve mechanism (1, 20) with a damping valve (4) which resists the oil flow from the oil chamber (41) to the reservoir (44) and a pressure-responsive throttle (6) which narrows a flow path from the oil chamber (41) to the damping valve (4) when a differential pressure between the cylinder (41) and the reservoir (44) exceeds a predetermined value, and a bypass valve (8) which allows the oil to flow from the oil chamber (41) to the reservoir (44) bypassing the pressure-responsive throttle (6) when the differential pressure increases further after exceeding the predetermined value, the shock absorber (D) can have different damping force characteristics depending on the speed regions of piston displacement.