Belleville washers, also known as conical washers or disc springs, are conical-shaped metal discs that function as a spring to provide high clamping force in tight spaces.
Unlike standard flat washers, they deflect when a load is applied, which helps maintain tension in a bolted connection even if it undergoes thermal expansion or vibration.
How They Work
- Spring Action: Their slightly cupped shape flattens as a nut or bolt is tightened, exerting a constant "push-back" force.
- Load Distribution: They distribute load evenly across a continuous arc rather than at a single point, like a split-lock washer.
- Versatility: They can be used individually or stacked in various patterns to change their mechanical properties.
Stacking Configurations
One of the most unique features of Belleville washers is that they can be stacked to achieve specific load or deflection (movement) goals:
- Parallel Stacking (Facing the same way): Increases the load capacity. For example, two washers stacked nested together will double the load capacity but provide the same deflection as one washer.
- Series Stacking (Facing opposite directions): Increases the deflection. Stacking them back-to-back creates more "travel" or springiness without increasing the total load they can support.
- Combination Stacking: Combines both methods to increase both load and deflection simultaneously for heavy-duty industrial needs.
Common Applications
- High-Vibration Environments: Used in heavy machinery and automotive engines to prevent bolts from vibrating loose.
- Thermal Cycling: Essential for electrical connections or steam flanges where metals expand and contract, which would otherwise cause a standard joint to lose its torque.
- Space-Constrained Joints: Frequently used in aerospace and medical devices where a traditional coil spring would be too bulky.
