SMALLEY Crest-to-Crest Spirawave springs, available from Circlips , are designed to handle tasks outside tolerances of conventional die stamped springs.
One example of an application of the Smalley springs is a brushless electric motor used to supply the energy to the power steering in smaller horsepower vehicles. The motor, driving a hydraulic pump located directly on the steering rack, eradicates the traditional belt drive from the crankshaft.
The conventional die-stamped wavy washer used to pre-load a standard 608 bearing on an 8mm shaft in the motor gave erratic results, leading to increased noise and excess wear.
These difficulties were caused by the limited working height available for the spring, which varied between 2.2mm and just 1.42mm when tolerance build up was taken into account. The die-stamped spring was unable to offer a controlled spring rate over these maximum and minimum conditions.
The Smalley Crest-to-Crest Spirawave spring is capable of operating consistently over these working heights. They are also able to develop similar forces to conventional round wire or helical springs while occupying a third or less space.
The Spirawave features a bespoke 4-turn spring design from narrow section 17-7 precipitation hardened stainless steel flat wire. It delivers the most effective spring rate within the space available. Because Smalley's manufacturing process uses no bespoke tooling, the lead-time and costs are reduced dramatically.
Finally, Spirawave springs are drawn from a continuous coil of single filament pre-tempered wire. This means that there are no associated tooling costs.