Belleville Disc (Washer) Springs – An Overview
A Belleville washer, also known as a Belleville disc spring, is a conical washer. And this conical shape which gives the washer a spring characteristic. Belleville disc spring one of the best alternative over coil spring is when there is size and space constraints. Disc Springs are often stacked to enhance performance characteristics. By stacking them in parallel, load bearing characteristics are enhanced. When stacked in series, greater deflection or travel is achieved.
Applications of Belleville Disc Springs
1. Alternative to coil spring when size and space are limited
2. Applications where need very high spring constant (for very high load applications)
3. Precise preloading of bolted connection
4. Flexible bolted connections
5. Protect bolts where large thermal expansion occurs
6. Spanning alignment holes, distributing bearing loads and for generating and sustaining the tension needed to hold assemblies together.
7. Heavy Duty Bolted section such as Bus Bars, Transformers, Rectifiers, Heat Exchangers, Transmission etc.
Types
1. Without Contact Flats:- These type will not have any flat surface at the contact area and if large forces are applied there are chances of particle generation.
2. With Contact Flats:- These type of washers provided with a machined flats on contact edges.
3. Serrated Belleville Washers:- These type of washer has the unique feature of radial serrations on both the concave and convex surfaces. When final flattening of the serrated safety washer occurs with the tightening of the screw, the serrations bite into the mating faces, thus preventing loosening of the screw caused by vibration.
Major Suppliers for Belleville Disc Springs
Catalogs
3. SCHNORR Unified Belleville Catalog
Common Materials Used
Steel - 50CrV4, CK75, 51CrV4, C 60S, C 67S, C 75S
Corrosion Resistant Steel - X 10 CrNi 18-8
Heat resistant steel - X 22 CrMoV 12-1, X 39 CrMo 17-1
Copper alloys - CuSn 8, CuBe 2
Standards Governing Belleville Disc Springs
DIN 2092, DIN 2093, DIN 6796
Note of caution
Note that spring constant (k) of Belleville disc spring are may not be constant. Don’t assume spring constant to be like in coil springs. So the force generated in Belleville disc spring may not proportional with deflection. Make sure that your design can take care this spring constant variation.
Labels: Fasteners, feature, Machine Design, Machine Elements, Spring
