Oscillation damper

An oscillation damper comprising at least two damper units movable with respect to each other, means defining at least two working chambers with at least one damping valve unit therebetween, a damping fluid within said working chambers said damping fluid being urged through said at least one damping valve unit in response to relative movement of said damper units with respect to each other, at least one by-pass channel system having at least one by-pass valve unit, said by-pass valve unit having a by-pass cross-sectional area, a, variable between an open value A.sub.o and a closed value A.sub.c, the respective value of said by-pass cross-sectional area, a, having an influence on the damping behaviour of said oscillation damper, said by-pass cross-sectional area, a, being variable by an actuating device moving through movement transmission means at least two valve members of said by-pass valve unit with respect to each other at a relative movement speed v, said valve members confining said by-pass cross-sectional area, a, a transition time period .DELTA.T corresponding to the relative movement of said valve members between an open value relative position P.sub.o providing said open value A.sub. o of said by-pass cross-sectional area, a, and a closed value relative position P.sub.c providing said closed value A.sub.c of said by-pass cross-sectional area, a, the relative movement speed v of said actuating unit, the transmission ratio of said movement transmission means and shaped parts of said valve members defining a cross-sectional area change function da/dt dependent on a transition time progress t during said transition time period .DELTA.T, the respective value of said cross-sectional area change function being variable in dependence of time progress t and being--when said valve members are close to said closed value relative position P.sub.c --considerably smaller than the quotient (A.sub.o -A.sub.c)/.DELTA.T, wherein A.sub.o is the open value cross-sectional area, A.sub.c is the closed value cross-sectional area and .DELTA.T is the transition time period, and the value of said cross-sectional area change function da/dt being--within a time interval adjacent the closed value relative position P.sub.c, which time interval is smaller than 20% of said transition time period .DELTA.T--smaller than 50% of the value of said function da/dt adjacent the open value relative position P.sub.o of said valve members.

An oscillation damper comprising at least two damper units movable with respect to each other, means defining at least two working chambers with at least one damping valve unit therebetween, a damping fluid within said working chambers said damping fluid being urged through said at least one damping valve unit in response to relative movement of said damper units with respect to each other, at least one by-pass channel system having at least one by-pass valve unit, said by-pass valve unit having a by-pass cross-sectional area, a, variable between an open value A.sub.o and a closed value A.sub.c, the respective value of said by-pass cross-sectional area, a, having an influence on the damping behaviour of said oscillation damper, said by-pass cross-sectional area, a, being variable by an actuating device moving through movement transmission means at least two valve members of said by-pass valve unit with respect to each other at a relative movement speed v, said valve members confining said by-pass cross-sectional area, a, a transition time period .DELTA.T corresponding to the relative movement of said valve members between an open value relative position P.sub.o providing said open value A.sub. o of said by-pass cross-sectional area, a, and a closed value relative position P.sub.c providing said closed value A.sub.c of said by-pass cross-sectional area, a, the relative movement speed v of said actuating unit, the transmission ratio of said movement transmission means and shaped parts of said valve members defining a cross-sectional area change function da/dt dependent on a transition time progress t during said transition time period .DELTA.T, the respective value of said cross-sectional area change function being variable in dependence of time progress t and being--when said valve members are close to said closed value relative position P.sub.c --considerably smaller than the quotient (A.sub.o -A.sub.c)/.DELTA.T, wherein A.sub.o is the open value cross-sectional area, A.sub.c is the closed value cross-sectional area and .DELTA.T is the transition time period, and the value of said cross-sectional area change function da/dt being--within a time interval adjacent the closed value relative position P.sub.c, which time interval is smaller than 10% of said transition time period .DELTA.T--smaller than 30% of the value of said function da/dt adjacent the open value relative position P.sub.o of said valve members.

An oscillation damper comprising at least two damper units movable with respect to each other, means defining at least two working chambers with at least one damping valve unit therebetween, a damping fluid within said working chambers said damping fluid being urged through said at least one damping valve unit in response to relative movement of said damper units with respect to each other, at least one by-pass channel system having at least one by-pass valve unit, said by-pass valve unit having a by-pass cross-sectional area, a, variable between an open value A.sub.o and a closed value A.sub.c, the respective value of said by-pass cross-sectional area, a, having an influence on the damping behaviour of said oscillation damper, said by-pass cross-sectional area, a, being variable by an actuating device moving through movement transmission means at least two valve members of said by-pass valve unit with respect to each other at a relative movement speed v, said valve members confining said by-pass cross-sectional area, a, said valve members having respective contact surfaces in surface contact with each other, each of said valve members being provided with at least one respective opening therethrough, said valve members being movable with respect to each other in a direction along a line s of relative movement following said contact surfaces, said openings overlapping each other in said open value relative position P.sub.o of said valve members and being free of overlapping in said closed value relative position P.sub.c of said valve members, said by-pass cross-sectional surface area, a, being in an overlapping condition of said openings confined by at least two edge lines, including a first edge line of an opening of a first one of said valve members and a second edge line of an opening of a second one of said valve members, said first and second edge lines being movable with respect to each other along said line s of relative movement, one of said first and second edge lines being a substantially straight line substantially perpendicular to said line s of relative movement and the other one comprising at least one stepped line section, a transition time period .DELTA.T corresponding to the relative movement of said valve members between an open value relative position P.sub.o providing said open value A.sub.o of said by-pass cross-sectional area, a, and a closed value relative position P.sub.c providing said closed value A.sub.c of said by-pass cross-sectional area, a, the relative movement speed v of said actuating unit, the transmission ratio of said movement transmission means and shaped parts of said valve members defining a cross-sectional area change function da/dt dependent on a transition time progress t during said transition time period .DELTA.T, the respective value of said cross-sectional area change function being variable in dependence of time progress t and being, when said valve members are close to said closed value relative position P.sub.c, considerably smaller than the quotient (A.sub.o -A.sub.c)/.DELTA.T, wherein A.sub.o is the open value cross-sectional area, A.sub.c is the closed value cross-sectional area and .DELTA.T is the transition time period.