Product Introduction

A hydraulic coupling is a mechanical device that transmits rotational speed using a liquid medium. Its driving input shaft is connected to the original drive, while its driven output shaft is connected to the load shaft. By adjusting the pressure of the liquid medium, the rotational speed of the output shaft can be changed. In an ideal state, as the pressure approaches infinity, the output speed equals the input speed, similar to a rigid coupling. As the pressure decreases, the output speed correspondingly reduces. Continuously changing the medium pressure allows for a stepless adjustment of the output speed below the input speed. The principle of power control and speed regulation for hydraulic couplings, as well as their efficiency, is based on the aforementioned characteristics. A hydraulic coupling is a power-consuming mechanical speed regulation device; the deeper the speed regulation (the lower the speed), the greater the loss. This is especially true for constant torque loads, where the unchanged input power of the original drive results in a proportional increase in loss power due to the speed loss. For loads like fans and pumps, where the load torque varies with the square of the speed, the input power of the original drive decreases with the square of the speed, resulting in relatively smaller loss power. However, the output power decreases with the cube of the speed, so the speed regulation efficiency is still very low. The speed regulation efficiency curve of hydraulic couplings has an average efficiency of around 50%. A non-rigid coupling that uses a liquid as the working medium, also known as a hydraulic coupling.

Product Real Photo

Product Features

The pump wheel and turbine of a hydraulic coupling form a sealed working chamber that allows for the cyclic flow of liquid. The pump wheel is mounted on the input shaft, while the turbine is mounted on the output shaft. As the power unit (internal combustion engine, electric motor, etc.) rotates the input shaft, the liquid is ejected by the centrifugal pump wheel. This high-speed liquid enters the turbine, causing it to rotate and transferring the energy obtained from the pump wheel to the output shaft. The liquid then returns to the pump wheel, creating a continuous flow. The hydraulic coupling transmits torque by changing the momentum moment through the interaction of the liquid with the blades of the pump wheel and turbine. Its output torque is equal to the input torque minus the friction torque, thus its output torque is always less than the input torque. The input and output shafts of the hydraulic coupling are connected by the liquid, with no rigid connections between the working components. The hydraulic coupling is characterized by its ability to eliminate shocks and vibrations; the output speed is lower than the input speed, and the speed difference between the two shafts increases with the load; it has good overload protection and starting performance; when the load is too heavy and the rotation stops, the input shaft can still rotate without causing damage to the power unit; when the load decreases, the output shaft speed increases until it approaches the input shaft speed. The transmission efficiency of the hydraulic coupling is equal to the ratio of the product of the output shaft speed and output torque (output power) to the product of the input shaft speed and input torque (input power). Generally, a hydraulic coupling can achieve higher efficiency when the normal operating speed ratio is above 0.95. The characteristics of the hydraulic coupling vary due to the different shapes of the working chamber and the pump wheel and turbine. If the oil in the hydraulic coupling is drained, the coupling is disengaged, serving as a clutch.