KEVOS® MAKEOS · Mechanics
Shoe Brake Stop Check (Stopping Torque, Lever Force, Lining Pressure, Heat)
What braking torque stops this rotating load in the time I want, what lever force does my shoe brake need, and are the lining pressure and drum temperature rise acceptable?
Check of a single-shoe drum brake stopping a rotating load: the torque to decelerate the inertia in the stopping time less any drag that helps (as the torque to accelerate a rotating load tool), the normal and friction forces on the shoe and the lever force for the pivot geometry, self-energising or not, with the self-locking check (as the shoe brake tool), shoe pressure, kinetic energy per stop, revolutions to stop and the drum temperature rise, checked against the force available, your pressure limit and temperature limit.
Open the calculatorRuns in your browser. No account needed.
How this tool works
Inputs, units and where to find them
| Input | Unit | Typical source |
|---|---|---|
| Inertia of the load at the brake shaft | kg·m² | Moment of inertia of everything being stopped, referred to the brake shaft. |
| Speed | rpm | Speed of the brake shaft when the brake is applied. |
| Stopping time wanted | s | Time in which the load must stop. |
| Drag torque helping to stop | N·m | Friction or load torque that also slows the load (0 to ignore). |
| Brake geometry | ||
| Drum diameter | mm | Diameter of the brake drum. |
| Coefficient of friction | Friction coefficient of the lining on the drum. | |
| Pivot to applied force | mm | Distance from the shoe pivot to the applied lever force. |
| Pivot to shoe normal force line | mm | Distance from the pivot to the line of the shoe normal force. |
| Offset of friction force line from pivot | mm | Offset of the friction force line from the pivot. |
| Rotation relative to the pivot | choice | Whether drum rotation helps or opposes the shoe application. |
| Shoe contact area | mm² | Contact area of the lining. |
| Limits | ||
| Lever force available | N | Force the operator, spring or actuator can apply to the lever. |
| Allowable lining pressure | MPa | Allowable pressure for the lining. |
| Drum mass | kg | Mass of the drum that absorbs the heat. |
| Drum specific heat | kJ/kg·K | Specific heat of the drum (cast iron or steel about 0.46 kJ/kg·K). |
| Largest drum temperature rise per stop | K | Largest temperature rise per stop you accept. |
Method and formulas
- Brake torque = J ω ÷ t − drag (as the torque to accelerate a rotating load tool, with deceleration).
- Friction force = torque ÷ r; normal force = friction ÷ μ; lever force = N (b ∓ μc) ÷ a, self-locking if b ≤ μc when self-energising (as the shoe brake tool); pressure = N ÷ area.
- Energy per stop = ½ J ω²; revolutions = n t ÷ 120; drum temperature rise = energy ÷ (m c).
- Example: stopping in 3 s needs 167.55 N·m and 1,187.2 N on the lever; each stop puts 15.791 kJ into the drum, 2.2886 K.
Limitations
- Short shoe with uniform pressure; long shoes need the pressure distribution.
- All energy assumed to go into the drum in one stop; repeated stops accumulate heat.
- Example values are illustrations. Replace them with values for your actual task.
Typical uses
- Size a hand or spring-applied drum brake
- Check a brake for a new stopping time
- Estimate drum heating per stop
Who it is for
- Machine designers
- Maintenance engineers
- Design engineers
What you get
- Stopping torque, energy and revolutions
- Shoe forces, lever force and pressure
- Drum temperature rise
Interpreting the result
- A self-energising shoe needs less lever force but its torque is very sensitive to the friction coefficient.
References
- Machinery’s Handbook, 29th edition (Industrial Press, 2012), printed pp. 2455–2459, 176–181. Topic reference; no source tables or recommended settings are reproduced.
WORKOS tools are screening and decision-support utilities. Verify important financial, engineering, safety, legal or operational decisions using appropriate professional standards and your organisation’s approved data.
Open the Shoe Brake Stop Check (Stopping Torque, Lever Force, Lining Pressure, Heat) calculator
