The fluid coupling hydraulic coupling hydraulic retarder liquid as the working medium of a non-rigid coupling, also known as hydraulic coupling. Of the pump and turbine wheel of the hydraulic coupler (see figure) to a closed working chamber enables a liquid circulating pump wheel is mounted on the input shaft, a turbine is mounted on the output shaft. The power machine (an internal combustion engine, a motor, etc.) is driven by the input shaft rotates, the liquid is a centrifugal pump wheel thrown. Such high-speed liquid after driving the turbine into the turbine rotation is transmitted to the output shaft, the energy obtained from the pump wheel. Finally, the liquid return pump wheel to form a cycle of liquidity. Hydraulic coupler by the liquid and the pump wheel, the interaction between the turbine blades to produce momentum moment changes to transmit torque. Its output torque is equal to the input torque minus the friction torque, so its output torque is always smaller than the input torque. The hydraulic coupling between the input shaft and the output shaft by liquid contact, the operating member does not exist between the rigid coupling. The characteristics of the hydraulic coupler is: can eliminate the shock and vibration; the output rotational speed is lower than the input rotation speed, and the two axes of rotation speed difference increases with load increase; overload performance and good starting performance, the load is too large when stalled input shaft can still be rotated without causing damage to the power machine; When the load is reduced, the increase in output shaft rotational speed until close to the rotational speed of the input shaft. The transmission efficiency of the hydraulic coupler is equal to the output shaft speed multiplied by the output torque (power output) the ratio multiplied by the input torque and rotational speed of the input shaft (input power). Usually the rotational speed of the normal condition of hydraulic coupler than in the 0.95 or more, a higher efficiency can be obtained. The characteristics of the fluid coupling device due to the working chamber and the pump wheel, the shape of the turbine differ. Such as venting of the oil of the hydraulic coupler, the coupler is in the disengaged condition, can play the role of the clutch. Hydraulic the Reducer performance parameters model applicable speed / r? Min braking torque N? The m moment coefficient / min? YZQ-2000S 450 1520 2000 53.1 × 10 Z510 920 2000 (kW)