An Overview of Belleville Washers
Belleville washers answer by many names: Belleville spring washer, cupped spring washer, coned-disc spring, conical spring washer, and disc spring. These unique conical-shaped metal discs support heavy loads with minimal deflection. They are a superb choice for applications that require high load bearing capacity, yet need resistance to vibrations and thermal expansion. In this comprehensive guide, we will delve into the design, application, advantages, disadvantages of the Belleville washer. We will also provide information on how to choose the right washer for your needs.
Belleville washers' distinct spring-like, conical shape allow them to compress and exert and equal amount of force in response to heavy loads. Unlike conventional helical springs with multiple coils, Bellevilles deflect into a flattened state when the load is applied. This secures the load better and provides resilience against vibrations and other adverse conditions. These washers are the preferred choice when working with heavy loads in confined spaces or when specific spring load requirements need to be met. Bellevilles are not a good choice for very light loads though, because they won’t deflect correctly.
Applications of Belleville Washers
These versatile washers were originally conceived from the works of Julien Belleville in 1867. Some of their first uses included landmines, artillery, and bolt action rifles.
Today, Belleville washers serve in a wide range of industries: aerospace, automotive, manufacturing, valve manufacturing, energy, and medical industries. Their use has expanded from military applications to civilian uses. Some notable applications include:
- Automotive Industry: They support pistons and cylinders in automobiles, reducing vibrations and noise while ensuring the integrity of the mechanical components.
- Construction: Stacks of these washers are used under buildings as vibration dampers, especially in areas prone to seismic activity.
- Aerospace Industry: They are employed to indicate swelling or shrinkage of wooden propellers in aircraft, enhancing safety and performance.
- Manufacturing: In manufacturing processes, these washers help maintain stability and prevent thermal expansion, ensuring machinery functions optimally.
How Belleville Washers Work
The unique conical shape of Belleville washers allows them to function as springs, compressing and providing resistance when bolts and nuts are tightened. Their convex shape ensures optimal axial loading, making them highly efficient in distributing loads evenly and absorbing shocks. When properly chosen and installed, Belleville washers can enhance the reliability of machinery and prevent bolt failures.
Belleville washers achieve different loads and deflections depending upon the ways they are stacked and used together.
- If you stack Bellevilles facing the same direction, you increase the load capacity. Two washers double the load, three washers triple it, and so forth.
- If you stack Bellevilles so they face in opposite directions, you increase deflection. Two washer double the deflection, three washers triple it, and so forth.
- If you combine the above stacking methods you increase the load capacity and the deflection. An example would be stacking two sets of parallel washers facing opposite directions.
Belleville washers can also be used with flat washers.
Design and Manufacture of Belleville Washers
Belleville washers are manufactured in compliance with DIN 2093 and DIN6796. DIN 2093 governs calculations for predictable deflection based on loads. DIN 6796 especially applies to heavy-duty Belleville washers used in static functions like bolted joint tightening.
Presetting is a critical step in the manufacturing process, where the washer is momentarily flattened to reduce its original unloaded height. Preset Belleville washers are typically used to maintain load or tension in bolted assemblies.
Advantages and Disadvantages of Belleville Washers
Belleville washers offer several advantages, including the ability to conserve space, provide a long service life, work in conjunction with coiled springs, and distribute loads evenly. They also excel in absorbing shocks, preventing bolt failures, and maintaining the positioning accuracy of ball bearings. However, it is crucial to choose the right washer for your application. Using them inappropriately can lead to disadvantages such as excessive compression for lighter loads.
How to Choose the Correct Belleville Washer
Selecting the right Belleville washer for your application involves considering factors like load, environment, and bolt size. To choose the correct washer, follow these steps:
- Determine the Load: Calculate the load the washer will bear to determine the required spring rate and deflection.
- Select the Material: Choose a material that can withstand the environmental conditions of your application, such as high temperatures or corrosive agents.
- Choose the Right Size: Ensure the washer fits snugly around the bolt, providing adequate support.
Belleville washers are essential components in numerous industries, offering reliable load bearing and shock-absorption capabilities. Their unique design, conical shape, and ability to distribute loads evenly make them a valuable choice for a wide range of applications. To harness the full potential of Belleville washers, it's crucial to select the right type, size, and material for your specific needs and to consider the appropriate stacking method. With their versatility and effectiveness, Belleville washers play a significant role in enhancing the reliability and performance of machinery and equipment across various sectors.