Calculation
TK = μ·FA·rm·z
Use the static or dynamic friction coefficient matching the operating state.
Roloff/Matek Kap. 13.2.6
Disc friction-clutch torque
Use the static or dynamic friction coefficient matching the operating state.
MINTSI
02
Result
Select a target and calculate.
Understand the inputs
- Clutch torque TK — Transmissible torque in the selected friction state.
- Friction coefficient μ — Static coefficient for holding or dynamic coefficient during slip.
- Clamp force FA — Total axial force on the friction pack.
- Mean friction radius rm — Effective radius of the annular friction surface.
- Number of interfaces z — Number of friction interfaces transmitting torque.
Example
μ=0.3, FA=4 kN, rm=100 mm and z=3 give 360 N·m.
Assumptions and limits
Uniform effective friction, known clamp force and mean radius; check heat and wear separately.
Understand Disc friction-clutch torque
Disc friction-clutch torque is a focused preliminary calculation based on Roloff/Matek. The calculator rearranges the closed-form relationship for every included quantity and deliberately separates this result from a complete component verification.
What does this quantity describe?
Each active friction interface contributes μFA rm; for z interfaces TK=μFA rm z.
Formula and variables
TK = μ·FA·rm·z
TK = μ FA rm z
| Symbol / input | Meaning |
|---|---|
| Clutch torque TK | Transmissible torque in the selected friction state. |
| Friction coefficient μ | Static coefficient for holding or dynamic coefficient during slip. |
| Clamp force FA | Total axial force on the friction pack. |
| Mean friction radius rm | Effective radius of the annular friction surface. |
| Number of interfaces z | Number of friction interfaces transmitting torque. |
Choose the inputs correctly
Choose μ as static friction for no-slip holding or dynamic friction during engagement. FA is total axial force, rm effective mean radius and z the interface count.
How to use the calculator
Select the target, enter all remaining quantities for the actual component, and verify the units. Then compare the result with the stated model limits and with the required strength, safety and operating checks.
Worked example
μ=0.3, FA=4 kN, rm=100 mm and z=3 give 360 N·m.
Understand the result and units
Static transferable and dynamic engagement torque differ with their friction coefficients; manufacturer ratings include further constraints.
The calculator converts internally to coherent SI units. Length, force, torque, stress and angle may therefore use the offered units; dimensionless factors are entered as decimals.
What is taken from Roloff/Matek
Only the closed-form relationship from Kapitel 13.2.6, Auslegung schaltbarer Reibkupplungen is used. Tabulated data, material limits and detailed design checks are not silently added; they remain explicit inputs or are expressly outside the model.
Typical applications
Disc friction-clutch torque supports option comparison, plausibility checks and early sizing within its machine-element cluster. Releasing a design requires the additional checks described in the cited chapter.
Assumptions, limits and common mistakes
Uniform effective friction and known mean radius; separately design pressure, engagement energy, heating, wear and actuation.
Common mistake: Typical errors are misreading the effective length or force, entering percentages instead of decimals, and treating a preliminary result as a complete verification. In particular: Uniform effective friction and known mean radius; separately design pressure, engagement energy, heating, wear and actuation.
Frequently asked questions
Is Disc friction-clutch torque a complete strength verification?
No. Uniform effective friction and known mean radius; separately design pressure, engagement energy, heating, wear and actuation.
Where do the equation and validity limits come from?
Roloff/Matek, Machine Elements, Kapitel 13.2.6, Auslegung schaltbarer Reibkupplungen; the local 21st edition was cross-checked against the available 24th edition.
Can I order the calculated value directly as a nominal size?
Only after matching it to available standard or manufacturer series and completing the additional safety, material and operating checks.