Door closer unit

A door closer unit comprising:

• a cylindrical housing with a partition axially extending from one side of its inner surface and having a first liquid path and a tiered shaft receiving nest on the center of its inner bottom;
• a moving body with a movable barrier having an outer surface in a sliding contact with the partition, protruding from its one side to be in sliding contact with the inner surface of the housing, and dividing the interior of the housing into first and second chambers, and a rotational shaft having a lower end rotatably housed in the shaft receiving nest and an upper end extending upward;
• rotating body return means disposed between the shaft receiving nest and the moving body's inner groove, and, when one of the moving body's rotational shaft and housing is fixed to a doorframe and the other is fixed to the door and rotates in one direction, applying a recovering force to a rotating body in a direction opposite to said direction;
• a high-viscosity liquid filling in the housing;
• first check valve means disposed on one side of the movable barrier, opening a second liquid path allowing the first and second chambers to communicate with each other when said rotating body rotates in one direction, and closing the second liquid path when the rotating body turns in a direction opposite to said direction;
• cover means rotatably supporting the rotational shaft of the moving body and sealing the upper portion of the housing;
• and
• speed control means regulating the amount of the liquid flowing from one chamber of high pressure to the other chamber of low pressure via the first liquid path of the housing when said rotating body is turned, thus controlling the speed of said rotating body;
• the door being opened if said rotating body is turned in one way, and the door being closed if the rotating body is turned in the opposite direction by the recovering force from the return means, when opening the door, the liquid flowing through said first and second liquid paths whereby the rotating body is turned at high speed, and when closing the door, the liquid flowing through the first liquid path only whereby the rotating body is turned at low speed.