Rotary damper, particularly for vehicle suspension

A rotary damper comprising:

• a rotating input member rigidly connected to a rotating mechanical member to rotate with the rotating mechanical member about an axis of rotation;
• a first cylinder and a second cylinder coaxially arranged on opposite sides of the axis of rotation;
• a first piston slidably mounted inside the first cylinder and defining with the first cylinder a first working chamber containing a first incompressible working fluid;
• a second piston slidably mounted inside the second cylinder and defining with the second cylinder a second working chamber containing a second incompressible working fluid;
• motion conversion mechanisms arranged between the rotating input member and the first and second pistons to convert a rotary motion of the rotating input member about the axis of rotation into reciprocating motion of the first and second pistons in phase with each other, whereby as a result of the rotary motion of the rotating input member in a first direction about the axis of rotation a volume of the first working chamber is reduced and a volume of the second working chamber is increased, while as a result of the rotary motion of the rotating input member in a second direction, opposite to the first direction, about the axis of rotation the volume of the first working chamber is increased while the volume of the second working chamber is reduced;
• a third cylinder;
• a fourth cylinder;
• a third piston which is slidably arranged inside the third cylinder and separates an inner volume of the third cylinder into a first main chamber, which is in fluid communication with the first working chamber and is filled with the first incompressible working fluid, and a first auxiliary chamber, wherein the first auxiliary chamber contains a first spring member arranged to apply onto the third piston a first elastic force acting against a first pressure force applied onto the third piston by pressure of the first incompressible working fluid in the first main chamber, and wherein the third piston is a floating piston sliding inside the third cylinder depending on a resultant force between said first elastic force and first pressure force applied onto the third piston, whereby when the volume of the first working chamber decreases, as a result of rotation of the rotating input member in the first direction, the third piston is caused to move to reduce the volume of the first auxiliary chamber, compressing the first spring member contained therein and increasing the first elastic force applied by the first spring member onto the third piston;
• and
• a fourth piston which is slidably arranged inside the fourth cylinder and separates an inner volume of the fourth cylinder into a second main chamber, which is in fluid communication with the second working chamber and is filled with the second incompressible working fluid, and a second auxiliary chamber, wherein the second auxiliary chamber contains a second spring member arranged to apply onto the fourth piston a second elastic force acting against a second pressure force applied onto the fourth piston by pressure of the second incompressible working fluid in the second main chamber, and wherein the fourth piston is a floating piston sliding inside the fourth cylinder depending on a resultant force between said second elastic force and second pressure force applied onto the fourth piston, whereby when the volume of the second working chamber decreases, as a result of rotation of the rotating input member in the second direction, the fourth piston is caused to move to reduce the volume of the second auxiliary chamber, compressing the second spring member contained therein and increasing the second elastic force applied by the second spring member onto the fourth piston;
• the first working chamber and the second working chamber being fluidically separated from each other and the first auxiliary chamber and the second auxiliary chamber being fluidically separated from each other, as well as from the first working chamber and the second working chamber, whereby said first incompressible working fluid is prevented from flowing from said first working chamber to said second working chamber and to said first auxiliary chamber and second auxiliary chamber, and whereby said second incompressible working fluid is prevented from flowing from said second working chamber to said first working chamber and to said first auxiliary chamber and second auxiliary chamber.