Characteristics Of Fluid Couplings

A hydraulic coupler is a flexible transmission device that possesses several unique characteristics compared to conventional mechanical transmission systems: it effectively eliminates shock and vibration; the output speed is lower than the input speed, and the speed differential between the two shafts increases as the load increases; it offers excellent overload protection and starting performance-should the device stall due to excessive load, the input shaft continues to rotate, thereby preventing damage to the prime mover; furthermore, as the load decreases, the output shaft speed increases until it nearly matches the input shaft speed, causing the transmitted torque to approach zero.

The transmission efficiency of a hydraulic coupler is equal to the ratio of the output shaft speed to the input shaft speed. Generally, under normal operating conditions, a hydraulic coupler achieves high efficiency when this speed ratio exceeds 0.95. The specific characteristics of a hydraulic coupler vary depending on the geometry of its working chamber, pump impeller, and turbine runner. Typically, the device relies on natural heat dissipation through its casing and does not require an external oil-cooling system. If the oil is drained from the hydraulic coupler, the device enters a disengaged state, effectively functioning as a clutch. However, hydraulic couplers also have certain drawbacks, such as relatively lower efficiency and a narrow range of high-efficiency operation.