Controllable vibration damper for motor vehicles

A variable dashpot for motor vehicles, comprising:

• a fluid-filled shock-absorbing cylinder;
• a piston rod with an end sliding back and forth inside said cylinder;
• a first piston mounted on said end of said piston rod, said first piston dividing said cylinder into two displacement sections;
• said first piston having valves sensitive to pressure variations during compression and suction phases, said first piston having also an exterior system of regulable attenuating valves determining the dashpot's attenuating force, said attenuating valves and said pressure-sensitive valves generating together four performance curves in each phase;
• each valve in said system of attenuating valves comprising further two valves mounted on a single body and a second piston for each said two valves displaced back and forth axially for opening and closing at least one part, one of said two valves being sensitive to pressure during a suction phase and the other of said two valves being sensitive to pressure during a compression phase, one said second piston opening and closing one port and the other second piston opening and closing another port;
• said attenuating valves being positioned oppositely and coaxially in a cylindrical valve housing comprising at least one of said sections;
• the second pistons establishing communications between said attenuating valves and one of two fluid-line connections by the second pistons so that at least one of said two pressure-sensitive valves will participate in attenuation and neither of said two pressure-sensitive valves will participate in attenuation;
• and electromagnetic means for displacing the second pistons;
• said second pistons being axially displaced by said electromagnetic means and being located axially outside, said pressure-sensitive valves being axially inside said valve housing;
• at least one channel in said system of attenuating valves to convey fluid between said ports opened and closed by said second pistons;
• said channel comprising a pipe surrounding said valve housing demarcating an interior valve receiving means;
• said fluid-line connections extending radially out of said valve housing;
• one of said fluid-line connections opening into said channel and another one of said fluid-line connections between said pressure-sensitive valves opening into an interior valve receiving means;
• said electromagnetically displaced second pistons opening and closing at least one port being located axially inside and said pressure-sensitive valves being located axially outside in said valve housing;
• said system of attenuating valves including at least one channel conveying fluid between said ports that are opened and closed by said second pistons;
• said channel being in a space between an inner surface of said valve housing and an outer surface of a pipe located therein;
• said system of attenuating valves varying the width of a bypass between said displacement sections of said cylinder.