Power springs are sometimes referred to as clock springs, spiral torsion, flat spiral springs, motor springs or brush springs. They are made by tightly winding a spring material on an arbour in a circular case and attaching the free end to a metal or plastic case which is designed to store and release rotational energy in the form of torque, that makes up a power spring can offer a high force output with minimal space requirements.
There are two basic types of power spring-" Conventional Power Springs" with a shape that spirals away from the centre in the same direction as it is wound, where the advantages are lower stress, best cycle life and easiest to manufacture.
Alternatively, the Prestressed Power Spring has a portion of its shape that spirals in the reverse direction of winding. It can create higher stresses that result in higher torque output up to 25% than a conventional power spring yields a flatter torque gradient.
Both methods have their advantages. The best option varies depending on the application and requirements. These springs are often designed for customer-specific applications and are used in the automotive, aerospace & defence, medical, industrial, electronics markets and commercial goods.
When considering a Power Spring design, there are four critical factors, such as Bore/ shaft (ID/OD), Load, Working height at which the load is applied. Material desired, and the other input parameters containing the wire thickness, wire radial wall, active number of turns, work height, and load at work height are the input data shown on the left table. And calculation results with spring rate (stiffness), working load (±10%), outer diameter at solid height, Working curve and Life cycles prediction where found in the down table.
