Product Introduction

A hydraulic coupler is a mechanical device that transmits rotational speed using a liquid medium. It connects the driven input shaft end to the original driving mechanism and the driven output shaft end to the load shaft end. By adjusting the pressure of the liquid medium, the speed of the output shaft can be changed. In an ideal state, as the pressure approaches infinity, the output speed equals the input speed, akin 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 coupler is an energy-consuming mechanical speed regulating device; the deeper the speed regulation (the lower the speed), the greater the loss, especially for constant torque loads. Since the original driving input power remains constant, the loss power increases proportionally with the speed loss. For loads like fans and pumps, where the load torque varies with the square of the speed, the original driving input power decreases at a rate proportional to the square of the speed, resulting in relatively lower loss power. However, the output power decreases at a cubic rate of the speed, and 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 is also known as a hydraulic coupling.

Product Actual Photos

Product Features

The impeller and turbine of a hydraulic coupling form a sealed working chamber that allows for the circulation of liquid. The impeller is mounted on the input shaft, while the turbine is mounted on the output shaft. As the power source (internal combustion engine, electric motor, etc.) rotates the input shaft, the liquid is ejected by the centrifugal impeller. This high-speed liquid, upon entering the turbine, drives it to rotate, transferring the energy obtained from the impeller to the output shaft. The liquid then returns to the impeller, creating a continuous flow. The hydraulic coupling transmits torque by changing momentum due to the interaction between the liquid and the blades of the impeller and turbine. Its output torque is equal to the input torque minus the friction torque, hence it 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's features include: the ability to eliminate shock and vibration; output speed lower than input speed, with the speed difference between the two shafts increasing with load; good overload protection and starting performance, allowing the input shaft to continue rotating even when the load is too high to prevent engine damage; and 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 product of the output shaft speed and output torque (output power) divided by the product of the input shaft speed and input torque (input power). Generally, a hydraulic coupling can achieve high efficiency when the speed ratio under normal operating conditions is 0.95 or higher. The characteristics of the hydraulic coupling vary due to differences in the shape of the working chamber and the impeller and turbine. If the oil in the hydraulic coupling is drained, the coupling is disengaged, acting as a clutch.