Motor Couplings
Motor couplings are flexible devices that provide distance changes along a lateral axis between a motor shaft and a device, like a valve shaft that needs to be actuated. They exhibit high torsional stiffness, which prevents system resonance. Motor couplings are used in medical systems like scanners, DNA analyzers and x-ray equipment, as well as home appliances like blenders, dishwashers and washing machines. Although they vary significantly, motor couplings are always composed of an outer casing with an axis and two sides, and a carriage shaft, where a carriage moves sideways along an axis of rotation and is surrounded by ball bearings.
Components of motor couplings are mostly made out of metal like steel, stainless steel and aluminum. Certain parts, like the spider in jaw couplings, are made of polyurethane or other plastic resin-based materials. Each motor coupling has different degrees of torque, shaft misalignment, stiffness, rpm and space requirements, and these factors must be taken into account when choosing a coupling for a motor application. There are five different types of couplings that are appropriate for motor applications. Beam couplings are good general purpose choices, Oldham couplings have high parallel misalignment capabilities, jaw couplings are best for shock absorption (because of their plastic dampening component), disc couplings are torsionally rigid and therefore have high misalignment capability, while bellows couplings offer the most rigid torsional stiffness.