Fluid couplings consist of a housing containing an impeller on the input or driving shaft and a runner on the output shaft. Both of these contain a fluid which is usually oil that is added to the coupling through a filling plug on the housing. The impeller, which acts as a pump, and the runner, which acts as a turbine, are both bladed rotors. Read More…

Leading Manufacturers
DieQua Corporation
Bloomingdale, IL | 630-980-1133Our shaft couplings are the best around! Not only do we provide you with exceptional levels of customer service but we also provide you with manufacturing and a repair service that you can count on. We are also capable of providing you with special designs. That’s right! Our design team will work closely with you in order to ensure that you are getting the product that will fit your specific requirements perfectly! Call or email us today for more information!

Ruland Manufacturing Company, Inc.
Marlborough, MA | 800-225-4234Ruland’s carefully made shaft collars, rigid shaft couplings & zero backlash motion control flexible shaft couplings, including beam, Oldham & bellows couplings, are available in both inch & full-metric dimensions. Our line has expanded to include metric shaft collars, metric rigid couplings & step bore rigid couplings. For 70 years, we have supplied custom-made products to meet special needs.

Hersey Clutch Company
Orleans, MA | 508-525-2533Hersey Clutch has been in business since 1963. With that kind of background and experience we have becomes leaders in application engineering. We specialize in finding solutions to our customer's problems regarding industrial power transmissions, brakes, clutches, couplings, universal joints, gearboxes, speed drives, friction material, crane electrification and more. Let us help you today!

US Digital
Vancouver, WA | 800-736-0194US Digital designs and manufactures flexible shaft couplings for motion control, automation and robotics. We ship standard products directly to domestic and international customers. We also offer optical encoders, inclinometers and switching power supplies plus other products.

Ringfeder Power Transmission
Westwood, NJ | 888-746-4333Ringfeder is a component and system provider with a global presence. Serving all industries including packaging, automation, energy, mining and transportation and defense. Ringfeder offers premium products including locking devices, shaft couplings and dampening technologies. Included in the coupling line are torsionally rigid disk, elastomeric and backlash-free servo-insert and metal bellows couplings.

The components of fluid couplings are generally made out of metallic materials-aluminum, steel or stainless steel. Fluid couplings are used in the automotive, railroad, aerospace, marine and mining industries. They are used in the transmissions of automobiles as an alternative to mechanical clutches. Forklifts, cranes, pumps of all kinds, mining machinery, diesel trains, aircrafts and rotationally-powered industrial machinery all use fluid coupling when an application requires variable speed operation and a startup without shock loading the system. Manufacturers utilize these couplings to connect rotary equipment such as drive shafts, line shafts, generators, wheels, pumps and turbines in a variety of automotive, oil and gas, aerospace, water and waste treatment and construction industries.
In a fluid coupling, the impeller and rotor are both bowl-shaped and have many radial vanes. They face each other but unlike gear couplings have no mechanical interconnection and never touch. Fluid is directed by the pump into the impeller. The driving turbine or pump is rotated by an internal combustion engine or electric motor imparting both linear and rotational motion to the fluid.
The velocity and energy is transferred to the fluid when the impeller rotates. It is then converted into mechanical energy in the rotor. Every fluid coupling has differing stall speeds, which is the highest speed that the pump can turn when the runner is locked and maximum input power is applied. Slipping always occurs because the input and output angular velocities are identical, and therefore the coupling cannot reach full power efficiency-some of it will always be lost in the fluid friction and turbulence.
Flexible shaft couplings such as fluid couplings are necessary because during operation, some types of shafts tend to shift, causing misalignment. Flexible couplings provide efficient accommodation for moderate shaft misalignment that occurs when the shafts' axes of rotation become skewed. Shaft movement is caused by bumps or vibration and it results in parallel, angular or skewed shaft misalignment.