Washers

Spring Washers for Axial Tolerance Compensation and Compact Preloading

Spring washers are space-saving spring elements that are loaded in the axial direction. They generate a defined preload, compensate for dimensional deviations and can absorb vibrations, noise, wear or temperature-related changes in length.

Compared with many helical compression springs, spring washers require only a small axial installation height. They are therefore particularly suitable for bearings, gearboxes, electric motors and other assemblies with limited installation space.

The Febrotec range includes:

• stamped wave spring washers,

• coiled wave spring washers,

• curved spring washers,

• multi-turn wave springs,

• wave wire spring washers,

• finger spring washers.

The different versions vary mainly in terms of spring travel, spring force, installation geometry, force tolerance and manufacturing method.

Further information on selection, design and application can be found in our Spring Washer FAQ.

Which Spring Washer Is the Right Choice?

Stamped Wave Spring Washers

Stamped wave spring washers are manufactured from flat spring strip and formed with several waves. When the washer is compressed axially, these waves generate a spring force.

Versions with three waves provide several evenly distributed contact areas. This allows the force to be applied around the circumference, which is particularly beneficial when axially preloading ball bearings.

Stamped wave spring washers are used to:

• compensate for axial dimensional tolerances,

• preload ball bearings,

• reduce operating noise and vibration,

• compensate for wear and settling,

• generate a defined axial retaining force.

The spring force is normally specified at a defined test height. This test height is not the same as the fully compressed height.

Coiled Wave Spring Washers

Coiled wave spring washers are formed into a ring from flat spring strip. Depending on the design, they have either an open gap or overlapping ends.

They are particularly suitable for applications requiring a more precisely defined spring rate or spring force. Compared with stamped versions, their force values can often be produced with tighter tolerances.

Coiled wave spring washers can also be designed to fit tightly inside a bore. This allows them to centre themselves within the assembly and prevents them from falling out unintentionally.

Typical applications include:

• ball bearing preloading,

• gearboxes and electric motors,

• tolerance compensation within housings,

• axial positioning of components,

• assemblies requiring a precisely defined preload.

Curved Spring Washers

Curved spring washers have a single, uniform curved profile. When loaded axially, the washer is progressively flattened.

They are suitable for medium spring forces, short spring travel and very small installation heights. Curved spring washers are used, for example, beneath screw heads, nuts, bearings and other axially loaded components.

Although compression close to the flat position may be possible, the normal working travel should generally remain below complete flattening. This helps to reduce high stresses and permanent deformation.

Curved spring washers must not automatically be regarded as tested locking devices for threaded joints. Their main purpose is to generate an axial spring force and compensate for dimensional changes.

Multi-Turn Wave Springs

Multi-turn wave springs consist of several consecutive turns with a wave-shaped geometry. They combine the small radial width of a spring washer with greater axial spring travel.

In certain applications, they can therefore replace cylindrical helical compression springs. Compared with a single-turn spring washer, they provide a longer working stroke while maintaining a compact installation height.

Multi-turn wave springs are suitable for applications such as:

• mechanical seals,

• valves and fittings,

• pumps,

• bearing assemblies,

• electrical connectors,

• compact return mechanisms,

• assemblies with limited axial installation space.

When selecting a multi-turn wave spring, the sleeve and rod diameters, free height, test height, spring force and number of turns must all be considered.

Wave Wire Spring Washers

Wave wire spring washers are manufactured from round spring wire. Their wave-shaped geometry generates a spring force when they are compressed axially.

They fit into restricted installation spaces and can be used to compensate for manufacturing tolerances, wear or temperature-related expansion. When suitably preloaded, they can also absorb vibrations and retain components in an axial position.

The load-deflection characteristic is approximately linear over a large part of the available spring travel. Close to the fully compressed position, the required force may increase more sharply due to increasing contact and friction.

Finger Spring Washers

Finger spring washers have several radially arranged spring fingers. These fingers can deflect largely independently of one another, allowing them to compensate for local dimensional deviations or uneven loading.

They are particularly suitable for the axial preloading of ball bearings. The elastic fingers can reduce vibrations and operating noise while helping to maintain an even bearing load.

Finger spring washers are suitable for applications such as:

• electric motors,

• gearboxes,

• fans and blowers,

• household appliances,

• precision mechanical assemblies,

• bearing arrangements with axial dimensional deviations.

When selecting a finger spring washer, the outside and inside diameters, bearing arrangement, free height, test height and minimum and maximum forces at the test point must be considered.

How to Select the Right Spring Washer

Proceed in the following order:

1. Determine the installation space: Define the available outside or sleeve diameter, inside or rod diameter and axial installation height.

2. Define the required spring force: Determine the force required at the intended operating point.

3. Determine the spring travel: Calculate the difference between the free height and the installed working height.

4. Consider the operating conditions: Distinguish between static, occasionally cycled and dynamic loading.

5. Check component tolerances: Consider manufacturing deviations, wear, settling and temperature-related changes.

6. Select the appropriate design: Choose between stamped, coiled, curved or multi-turn versions according to the required travel, force, installation geometry and precision.

7. Select the material: Consider corrosion, temperature, humidity and contact with surrounding media.

The specified test force always applies at the corresponding test height. Both values must therefore be considered together when selecting a spring washer.

Materials for Spring Washers

Depending on the design and dimensions, spring washers are available in a range of spring materials.

Spring Steel

Spring steels such as 1.1200, 1.1231, 1.1248 and 1.1274 provide high strength and are suitable for many standard industrial applications. Without a suitable coating or protective treatment, however, these materials are not permanently corrosion-resistant.

Stainless Spring Steels

Stainless spring steels such as 1.4310 and 1.4568 are suitable for humid environments and applications with increased corrosion-resistance requirements.

Material 1.4310 may become slightly magnetic as a result of cold forming during manufacture. Its suitability for permanent contact with seawater or media containing high chloride concentrations must be assessed separately.

Typical Applications of Spring Washers

Spring washers are commonly used in:

• ball and roller bearing arrangements,

• electric motors and generators,

• gearboxes,

• pumps and compressors,

• valves and fittings,

• machinery and fixtures,

• automotive components,

• electrical connectors,

• measuring and control equipment,

• precision mechanical devices.

Within an assembly, they can maintain a defined preload while compensating for manufacturing tolerances, wear or thermal expansion.

Custom Spring Washers

In addition to the standard versions available from stock, spring washers can be manufactured according to individual requirements.

Customisable characteristics include:

• outside, inside, sleeve and rod diameters,

• material or wire thickness,

• free height and working height,

• spring travel,

• spring rate and spring force,

• number of waves or turns,

• material and surface finish.

For a technical enquiry, please provide information about the available installation space, required spring force, intended spring travel, type of loading and operating conditions.

Frequently Asked Questions About Spring Washers

What is the difference between a spring washer and a disc spring?

Depending on the design, spring washers may be waved, curved or equipped with individual spring fingers. They are often used for low to medium forces and axial tolerance compensation. Disc springs, by comparison, can generate very high forces over short spring travel.

Which spring washer is suitable for bearing preload?

Stamped wave spring washers, coiled wave spring washers and finger spring washers are particularly suitable for preloading ball bearings. The correct choice depends on the required force, spring travel, installation space and permissible force tolerances.

What do test height and test force mean?

The test height is the defined height to which a spring washer is compressed. The test force is the axial spring force generated at this height. Both values must be considered together when selecting a spring washer.

Can spring washers be compressed completely flat?

This depends on the design. Curved spring washers can generally be loaded close to the flat position. For stamped, coiled and multi-turn wave spring versions, the specified test values and load limits must be observed.

Do spring washers prevent threaded joints from loosening?

The spring washers offered here are primarily intended as axial spring elements and for tolerance compensation. Whether they can reliably prevent a threaded joint from loosening must be assessed separately for the specific application.