Disc springs for automotive applications have to do three difficult things at once: deliver high force in almost no space, survive millions of cycles, and hold that force while the surrounding metal heats and cools. SCHNORR disc springs are used in turbochargers, shock absorbers and brake force amplifiers, and are trusted across automotive, energy, heavy machinery, rail and industrial manufacturing.
Automotive is one of the toughest briefs in mechanical design, not because the loads are the highest, but because everything is constrained at once. The space is fixed by the package. The life is fixed by the warranty. The temperature is whatever the neighbouring component decides.
Three reference applications show how a disc spring earns its place in that environment.
Turbochargers: force that survives heat
A turbocharger disc spring works next to exhaust gas. Standard carbon spring steel loses force long before it shows visible damage, so the material choice moves up: X22 CrMoV 12-1 is effective to 500 degrees C, and Inconel X718 and X750 are suitable up to 600 degrees C with excellent corrosion resistance.
The behaviour to design around is creep. A combination of temperature, time and tension can cause a gradual loss of installation height or spring force, so a joint that relies on a fixed preload for the life of the vehicle needs that allowed for in the calculation rather than discovered in the field.
Shock absorbers: millions of cycles, predictably
A shock absorber spring is a fatigue problem. Two disc spring properties matter here. They are largely self damping, which suppresses the internal resonance that kills coil springs in high frequency duty, and they have a long and predictable service life under dynamic load, which is what lets a designer put a number on it.
Presetting also means there is no setting under static loads, so the assembled height does not drift while the vehicle sits on a dealer forecourt for six months.
Brake force amplifiers: high load, short stroke
The brake force amplifier is the clearest case for the geometry itself. A conical washer gives high spring loads from an efficient use of space, and stacking sets the curve. Parallel stacks add force at the same deflection. Series stacks add deflection at the same force. Combining both realises a progressive characteristic, which is exactly the pedal feel a braking system is often specified to produce.
And every one of those joints is bolted
Behind the spring is the fastener holding the assembly together, usually in a location that vibrates constantly. This is where an automotive vibration washer does its work. Original SCHNORR serrated safety washers secure joints through friction and mechanical locking together, and in Junker testing they maintained pretension force after 2,000 cycles, with performance superior to split lock, detent edged, ribbed and spring washers, and equivalent to a wedge-locking washer.
They can also be reused two or more times without losing securing effect, which matters on assemblies that get opened during rework or service.
A practical specification order
- Temperature at the joint, which sets the material before anything else.
- Load and available installation height, which sets the stack.
- Cycle count and duty, which decides how much margin to hold.
- Corrosion exposure and finish.
- The fastener and its locking element, specified rather than assumed.
SCHNORR products sit in turbochargers, shock absorbers and brake force amplifiers today, alongside stationary railway clamps, ski lift cable clamps, elevator emergency brakes, conveyor sliding hubs, stamping machines, spindles, offshore drills and safety valves. If a joint on your programme is fighting one of these constraints, the standard range is the place to start and special sizes are available where it does not reach.
- SCHNORR disc springs are used in turbochargers, shock absorbers and brake force amplifiers.
- They are applied across automotive, energy, heavy machinery, rail and industrial manufacturing.
- X22 CrMoV 12-1 is effective to 500 degrees C. Inconel X718 and X750 are suitable to 600 degrees C.
- Creep from temperature, time and tension can cause loss of installation height or spring force.
- Disc springs are largely self damping and have a long, predictable service life under dynamic load.
- Presetting means no setting under static loads.
- In Junker testing, SCHNORR safety washers maintained pretension force after 2,000 cycles and can be reused two or more times.
Frequently asked questions
Why use a disc spring instead of a coil spring in an automotive assembly?
A disc spring delivers high spring loads from a very short installation length, is largely self damping, and gives a long and predictable service life under dynamic load. Stacking also lets the load deflection curve be shaped to the application.
What material suits a disc spring near an exhaust or turbocharger?
X22 CrMoV 12-1 is effective to 500 degrees C, though it is not corrosion resistant. Inconel X718 and X750 handle up to 600 degrees C with excellent corrosion resistance.
Do disc springs lose force at high temperature?
They can creep. A combination of temperature, time and tension may cause a gradual loss of installation height or spring force, so it should be allowed for in the calculation.
How do you stop fasteners loosening on a vibrating automotive assembly?
Use a locking element that works through friction and mechanical locking together. SCHNORR serrated safety washers maintained pretension force after 2,000 cycles in Junker testing, outperforming split lock, detent edged, ribbed and spring washers.
Can a disc spring stack give a progressive spring rate?
Yes. Combining series and parallel stacking in one stack realises various characteristic curves, including a progressive response.