Working principle of door closer

The basic components of the hydraulic door closer include support guides, transmission gears, return springs, one-way valves, rack plungers, throttle valve cores and housings, end covers, sealing rings and connecting rods. The shell and connecting rod play the role of fixing the door closer and connecting the door leaf and the door frame.

The working principle of the door closer is: when the door is opened, the door body drives the connecting rod to move, and makes the transmission gear rotate, driving the rack plunger to move to the right. When the plunger moves to the right, the spring is compressed, and the hydraulic oil in the right chamber is also compressed. The one-way valve ball on the left side of the plunger is opened under the effect of oil pressure, and the hydraulic oil in the right cavity flows into the left cavity through the one-way valve. When the door opening process is completed, because the spring is compressed during the opening process, the accumulated elastic potential energy is released, and the plunger is pushed to the left, driving the transmission gear and the door closer connecting rod to rotate, and the door is closed.

During the release of the spring, due to the compression of the hydraulic oil in the left chamber of the door closer, the check valve is closed, and the hydraulic oil can only flow out through the gap between the housing and the plunger, and through the small hole on the plunger and the 2 The flow path equipped with a throttle spool returns to the right chamber. Therefore, the hydraulic oil constitutes resistance to the release of the spring, that is, the effect of buffering is achieved through throttling, and the closing speed of the door is controlled. The throttle valve on the valve body can be adjusted to control the variable closing speed of different stroke sections. Although the structure and size of door closers produced by different manufacturers are different, the principle is the same.