A rotary damper is a minor maintenance-free mechanical component, which is commonly used in our daily life and work. For example, when you push a toilet lid, the toilet lid will be softly closed. Here an important role plays the rotary damper. So, you may be interested in how the rotary dampers work? Following is a brief explanation:
Rotary Dampers belong to minor maintenance-free oil fluid viscous dampers. From the basic structure, generally, a rotational damper is made of its main body, a rotor (rotating shaft), a cover, and viscous oil inside its sealed main body. As shown in the following drawing 1, when the rotor works, the viscosity of the sealed oil in the body will create resistance to the movement of the rotor. This resistance (or called viscous friction）will slow down the movement speed of the object. When the damper moves, its torque is generally influenced by the viscosity of the viscous grease. The damping torque is inversely proportional to the surrounding temperature and directly proportional to the rotation speed.
Picture: Basic Structure of Rotary Damper
The basic working principle of most rotary dampers is the same one. Only the vane damper has its unique characteristics in its operation. The vane damper is basically the same as the general structural principle of the rotary damper. When the blade damper moves, the rotating shaft drives the blades inside the sealing body to move. Due to the viscosity of the grease inside the sealing body, the difference in the size of the gap between the blade and the body produces different torque. Similarly, the torque of the blade damper is inversely proportional to the temperature, and proportionate to the speed when the rotor (rotating shaft) rotates.
Picture:Structure of Vane Damper
There are also extra dampers for their structure and movement methods. We can generally see for those common types of linear dampers, gas spring damper, etc. These types of damper are used together with springs. Because it is not involved in the scope this article, we will not explain them in this article.