Stacking direction decides what you gain. In a series stack, deflections add up at the same force, so you get more travel. In a parallel stack, forces add up at the same deflection, so you get more load. Combining the two in one stack lets you shape almost any load deflection curve. Every stack needs a guide element to prevent lateral movement, and inside guidance on a bolt or shaft is preferred.
A disc spring is a cone shaped washer that carries load along its axis. On its own it does something no coil spring can: it delivers a very high force in a very short installation length. Understanding how disc springs work in stacks is what turns that into a design tool, because the same part can be arranged to give you travel, load, or a curve that changes as it compresses.
Why engineers reach for disc springs
- Efficient use of space, providing high spring loads in a small space.
- A linear or progressive load deflection characteristic, depending on how the stack is built.
- Largely self damping, which matters under dynamic load.
- Long and predictable service life under dynamic load.
- Presetting means no setting under static loads, so the installed height holds.
Series stacking: more travel, same force
Stack springs facing alternately, cone against cone, and each spring deflects under the same force. The deflections are additive, so a stack of four gives roughly four times the travel of one spring at the same load. Use a series stack when you need to accommodate movement, thermal growth or wear while keeping the force roughly constant.
Parallel stacking: more force, same travel
Nest springs in the same direction and the forces are additive at the same deflection. Two in parallel give roughly double the load in almost the same length. This is the arrangement for clamping, preload and brake style applications where the space is fixed and the load has to go up. Parallel stacks also carry more internal friction, which adds damping.
Combined stacking: shaping the curve
The conical shape means the two arrangements can be mixed in a single stack, for example pairs in parallel repeated in series. That is how various characteristic curves are realised, including a progressive response where the stack gets stiffer as it compresses. If a specification asks for a soft initial take up and a hard end stop, a combined series and parallel stack is usually the answer.
Guidance: the detail that decides service life
A stack has to be held straight. Without guidance the springs shift sideways, contact wears unevenly and life falls short of the calculation. The rules for a disc spring guide element are short:
- A guide element is needed to prevent lateral movement.
- Inside guidance on a bolt or shaft is preferred, though outside guidance is acceptable.
- Guide elements and abutments should be hardened to at least 60 HRC, with a minimum case depth of 0.8 mm, where possible.
- The guide surface should be smooth and, if possible, ground.
- For static applications, guides can be left unhardened.
The standards, and what they cover
SCHNORR disc springs are manufactured to DIN EN 16983 for quality requirements and dimensions, and DIN EN 16984 for calculation. These replaced DIN 2093 and DIN 2092 respectively, so older drawings often still carry the previous numbers. Tolerances are defined for overall height, thickness, load and diameter, which is worth checking against your stack height budget before you commit the housing.
Where stacks earn their place
Disc springs support dynamic processes under extreme force and load conditions, and they are trusted across automotive, energy, heavy machinery, rail and industrial manufacturing. Real joints include turbochargers, shock absorbers, brake force amplifiers, stationary railway clamps, ski lift cable clamps, emergency brakes in elevators, sliding hubs in conveyor drives, percussion drilling machines, stamping machines, spindles, offshore drills and safety valves.
If you have a load and a space envelope but no part number yet, that is the normal starting point. Send the two numbers and the duty cycle, and the stack can be worked back from there. Standard sizes are in the Product Finder, and CAD models are available for layout work.
- In a series disc spring stack, deflections are additive at the same force.
- In a parallel stack, forces are additive at the same deflection.
- Combining series and parallel stacking allows various characteristic curves to be realised.
- Disc springs give high spring loads in a small space, are largely self damping, and do not set under static loads once preset.
- A guide element is required to prevent lateral movement. Inside guidance on a bolt or shaft is preferred.
- Guides and abutments should be hardened to a minimum of 60 HRC with a minimum case depth of 0.8 mm. Static applications can use unhardened guides.
- SCHNORR disc springs are manufactured to DIN EN 16983 (quality and dimensions) and DIN EN 16984 (calculation), formerly DIN 2093 and DIN 2092.
Frequently asked questions
What is the difference between stacking disc springs in series and in parallel?
In series, deflections are additive at the same force, so the stack gives more travel. In parallel, forces are additive at the same deflection, so the stack gives more load in the same length.
Can I get a progressive spring rate from disc springs?
Yes. Combining series and parallel stacking in one stack allows various characteristic curves, including a progressive load deflection response.
Do disc spring stacks need a guide?
Yes. A guide element prevents lateral movement. Inside guidance on a bolt or shaft is preferred, and guides should ideally be hardened to at least 60 HRC with a smooth, ground surface. Unhardened guides are acceptable for static applications.
Which standards apply to disc springs?
DIN EN 16983 covers quality requirements and dimensions, and DIN EN 16984 covers calculation. They replaced DIN 2093 and DIN 2092.
Will a disc spring stack lose height over time?
Presetting means there is no setting under static loads, and disc springs have a long and predictable service life under dynamic load.