Damping unit

Claim 1

A damping unit comprising a cylinder (1) having an axis and two cylinder ends, a cavity (4,5) being confined within said cylinder (1) between said two cylinder ends, a piston rod (3) sealingly guided through at least one of said two cylinder ends and axially movably extending inwards and outwards of said cavity (4,5), said piston rod (3) being provided with a piston unit (2) within said cavity (4,5), said piston unit (2) separating two working chambers (4,5) from each other within said cavity (4,5), said working chambers (4,5) containing a damping fluid, said piston unit (2) comprising a carrier member (16) fixed with respect to said piston rod (3), said carrier member (16) being provided with a plurality of axial bores (6), said axial bores (6) having two respective bore ends opening into respective valve seat faces (17c) of said carrier member (16), said valve seat faces (17c) being substantially perpendicular to said axis and adjacent respective working chambers (4,5), two respective annular valve members (9,10) being allocated to the respective valve seat faces (17c), said valve members (9,10) having respective radially outer and radially inner peripheral faces (20,9b) and a respective valve face (21) opposite to a respective valve seat face (17c), said valve members (9,10) being axially movable relative to the respective valve seat faces (17c) between a respective damping position closer to the respective valve seat face (17c) and a respective opening position more remote from the respective valve seat face (17c), said valve members (9,10) being axially bridged by at least one substantially axially extending gap (15) adjacent at least one of the respective radially outer and radially inner peripheral faces (20,9b), a plurality of respective compression springs (11) being provided within at least part of said axial bores (6) and extending therethrough, said compression springs (11) having respective opposite ends engaging both valve members (9,10) and urging them towards the respective opening position, said valve members (9,10) approaching the respective damping positions in response to increased pressure of damping fluid in the respective working chamber (4,5) resulting from increased axial speed of movement of said piston unit (2) in a respective axial direction with respect to said cylinder (1), characterized in that at least one face (21) of a pair of a valve seat face (17c) and a valve face (21) allocated to each other is provided with axial projection means (30) and recess means (23,13), said projection means (30) engaging the other face (17c) of said pair in the respective damping position, said recess means (23,13) and said at least one gap (15) providing in said respective damping position a restricted flow communication for said damping fluid from the respective bore ends to the respective working chamber (4,5).