Generally, washers used for construction purposes tend to distribute the load or force between two fastening components, but these tiny spacers can provide more specific functionality. They have what is referred to as axial flexibility or deformation resistance, thus preventing loosening usually caused by vibration and other forces. There are many subtypes of washers that perform in this way and one of the most common is spring washers.
When these washers are subjected to load, the irregularities in its structure squeeze-in, responding to a structural balance that causes them to return to a predetermined shape. They are typically used when the assemblies must avoid rattling, maintain tension, counteract expansion and contraction post-assembly, and provide a controlled reaction when subjected to varying loads.
The spring washers have further subtypes, some of these are:
- Belleville – These washers support high loads with minimal deflection and are used for thermal expansion applications or in a shock absorbing capacity.
- Crescent – These washers support smaller loads and allow small deflection. They are used for load cycling applications.
- Finger – These washers combine the benefits of crescent and wave washers and are used for noise and vibration dampening.
- Wave – These washers offer moderate load and deflection capacity, used for cushioning or spacing. The number of waves in their surface affects their deflection capabilities.
Among the most widely used of these are Belleville washers. Their conical shape lends a great deal of axial force. Wave washers are also among the most frequently used in the category of spring washers. They get their name from the wave-like shape in the axial direction, which imparts the washer with a spring pressure when subjected to load.
Now let’s look at some factors that are integral to spring washer performance.
Spring washers have to cope with either static or dynamic load. In the case of static loads, the washer’s function is to maintain the load, which might come at the cost of exceeding its elastic load rating. But for dynamic load, it works as a flexing spring. It’s important to note the yield limit of a spring washer as a permanent disfiguration can occur if this limit is exceeded.
Spring washers are very important in the category of small machines. They can symmetrically deflect the load around their axis by linear accelerating or decelerating means. They may be used in stacks to create a set or series, allowing the load and deflection capacity to fluctuate without disturbing the forces involved in terms of material.
Spring washers sustain elastic (reversible) deformation due to load application, and the degree of this deformation depends on construction material. However, if a washer is stressed beyond its capacity or nears completion of its lifecycle, it may go through deformation, resulting in partially irreversible deflection.
Some of the spring washers may go through a permissible degree of slight deformation after the first compression. In such cases, they are not capable of retaining their original form, even though the washer is totally fine in terms of mechanics.
This concept is known as setting and might be chosen by the manufacturer preset in what is referred to as a scragging process. Some other possibilities for the production procedure include shot peening and corrosion resistant coating to increase the washer’s longevity.
Spring washers are sometimes used as a type of lock washer, meant to remove rattling or vibration to avoid a possible turning or unscrewing of the bolt. They are sometimes used in cases where coil springs are either not feasible or too large.
These tiny devices can be employed in different types of pumps and valves, aerial cable cars, machine presses, certain types of couplings, electrical transformers—particularly the overload protection parts—and boiler suspension systems.
As different spring washers provide different capabilities, you’ll want to carefully consider their performance parameters and the unique needs of your application. Spring washers of all types can be easily sourced from a standard and metric Belleville washer manufacturer like Superior Washer.
With all washers and spacing components, there are many options and factors to account for but they can make a great difference in the success of a structure, piece of equipment, or hardware assembly.