What is a viscous coupling, and how does it function?
Viscous or fluid couplings are used to transfer power. They are widely used in industry and can be found in motor vehicle automatic transmissions. A fluid coupling has two main parts: the input member (impeller) and the output member (runner). Both the impeller and runner have vanes, which are used to direct the fluid flow. There is no mechanical connection between the two shafts, since all power is transmitted by an operating fluid, usually oil. As the impeller rotates, its vanes direct the fluid towards the runner, which is caused to rotate. A major advantage of fluid couplings is that the input shaft cannot be stalled if the output shaft is stopped. In addition, the motor driving the impeller can be operated at its most efficient operating point, regardless of the amount of torque delivered to the runner shaft. Oil is widely used in industry for power transmission applications, not only with the fluid couplings described here, but also with actuators and motors. Oil has several adva
The viscous coupling is often found in all-wheel-drive vehicles. It is commonly used to link the back wheels to the front wheels so that when one set of wheels starts to slip, torque will be transferred to the other set. The viscous coupling has two sets of plates inside a sealed housing that is filled with a thick fluid, as shown in below. One set of plates is connected to each output shaft. Under normal conditions, both sets of plates and the viscous fluid spin at the same speed. When one set of wheels tries to spin faster, perhaps because it is slipping, the set of plates corresponding to those wheels spins faster than the other. The viscous fluid, stuck between the plates, tries to catch up with the faster disks, dragging the slower disks along. This transfers more torque to the slower moving wheels — the wheels that are not slipping. When a car is turning, the difference in speed between the wheels is not as large as when one wheel is slipping. The faster the plates are spinning
The viscous coupling is often found surrounded by all-wheel-drive vehicles. It is commonly used to correlation the back wheel to the front wheels so that when one set of wheel starts to slip, torque will be transferred to the other set. The viscous coupling has two sets of plates inside a hermetic housing that is occupied with a tacky fluid, as shown in below. One set of plates is connected to respectively output shaft. Under normal conditions, both sets of plates and the viscous fluid spin at duplicate speed. When one set of wheels tries to spin faster, probably because it is slipping, the set of plates corresponding to those wheels spins faster than the other. The viscous fluid, stuck between the plates, tries to take into custody up with the faster disks, dragging the slower disks along. This transfers more torque to the slower moving wheel — the wheels that are not slipping. When a vehicle is turning, the difference in speed between the wheel is not as large as when one reins is s
