Rotor Clip answers common questions on wave springs

Wave springs are frequently beneficial as an alternative to coil springs, but what types are available, and what design benefits do they bring? We asked the experts at Rotor Clip.

How can I benefit by using wave springs in place of coil springs?

Any application that uses a coil spring can also use a wave spring with added engineering advantages. They use minimal axial space when compared to coil springs. In comparing a wave and a coil spring that have the same force, the coil spring would require twice the working height. Wave springs provide a more consistent force due to their deflection curves having a wider and flatter linear force region.

The characteristics of wave springs are easily adjustable, as well as their dimensions during running series without any tooling modifications. There is no tooling cost for custom designs and the wave springs can also provide lower spring rates.

What types of wave springs are available?

Wave springs come in two forms: single-turn and multi-turn. Single-turn wave springs are suited for applications that include bearing pre-load, connector and fluid power seals, and noise and vibration attenuation. They are able to self-locate in holes, which helps ease assembly. Single-turn wave springs typically replace stamped wave washers.

Multi-turn wave springs are for applications such as mechanical seals and a variety of power transmissions and fluid power systems. Examples are in equipment used in automotive, medical and industrial automation. Designs that use coiled springs or entire stacks of disc springs can be replaced by multi-turn wave springs, eliminating an assembly step as well.

What materials do wave springs come in?

Wave springs come in a variety of materials, based on the applications. Such materials available are carbon spring steel (SAE 1070-1090) as well as stainless steel (17-7PH Cond.CH900, AISI 302 & 316). Wave springs can be made using exotic alloys such as Inconel, Elgiloy, Hastelloy, beryllium-copper, and phosphor-bronze to withstand a high corrosive environment and/or high operating temperatures.

What design benefits do wave springs offer that will help maximise the efficiency of the engineering design?

The use of wave springs provides engineering benefits that help the overall design of your part. Wave springs typically need just 50% of the work height of a coil spring to deliver an equivalent force in static applications and 30% in dynamic applications. For dynamic applications, design the axial space accordingly to help minimise bending stress by providing more space due to the more turns required.

Another design factor is the wave spring force requirements. Wave springs have a lower and more linear spring force compared to coil springs (about 30% to 70% deflections). This helps wave springs be more predictable, which results in tighter control of specific spring-force requirements. This allows mechanical seals to be appropriately designed to balance excess wear due to high pre-loads versus leaks that occur from having too low a preload.

This force provided by wave springs is consistent across a range of deflection meaning spring cavities and shafts can be loosened, which aids in lowering tooling cost during the manufacture of the part.

Another benefit of wave springs is that they experience torsional load. The forces produced by a wave spring are only transmitted in the intended axial direction. This helps prevent rotational wear within the part. In terms of travel, multi-turn wave springs offer far more and can replace assemblies of multiple-disc springs. Using a single wave spring will help reduce the cost as well as prevent mistakes by minimising the number of required parts for assembly.

Which industries can benefit by implementing wave springs?

Wave springs are designed to be used in several parts that cover a variety of industry. They are suited to handle different environments that include uses in the automotive and petrochemical industry – both of which experience hazardous and corrosive environments such as salt fog. Typical mechanical equipment that uses wave springs range from pumps and compressors to seals, filters, and connectors.

What is the life-cycle, or what are the maintenance benefits of wave springs?

Wave springs can increase the life-time of the whole product because they provide a more equal force during the product’s lifetime compared to alternative spring elements. Since they do not suffer from torsional loading or twisting, they are more effective than coil springs, adding to the overall efficiency of the part. Wave springs also help reduce wear (for example, rotational wear or pre-load wear). This adds to the longevity of the part.