Disk Clutch / Brake Friction Torque

Shigley Ch. 16: uniform WEAR (the design standard) T = F mu N (ro + ri)/2 with the pressure peaking at the inner radius, p_max = F/(2 pi ri (ro - ri)); uniform PRESSURE T = (2/3) F mu N (ro^3 - ri^3)/(ro^2 - ri^2) for a fresh facing. F is the axial clamp force, mu the facing friction, ro/ri the outer/inner radii, N the number of friction interfaces (a single-plate clutch clamps both faces, N = 2). 1,000 lbf, mu 0.3, ro 3, ri 2, N 1 gives 750 in-lbf (wear) vs 760 (pressure) and 79.6 psi at the inner edge; a real single-plate clutch (N 2) doubles it to 1,500 in-lbf. Sizes a clutch or disk brake from its actuating force. Heat of engagement, wear life, and band/cone brakes are separate. A design aid; Shigley and the facing maker govern.

Uniform wear: T = F mu N (ro + ri)/2. Uniform pressure: T = (2/3) F mu N (ro^3 - ri^3)/(ro^2 - ri^2). Max pressure (uniform wear): p_max = F/(2 pi ri (ro - ri)). N = friction interfaces (single plate = 2).

The disk-clutch friction torque under the uniform-wear and uniform-pressure assumptions (Shigley, Mechanical Engineering Design, Ch. 16 -- clutches and brakes), by name.

The clutch-torque equations are standard published machine-design results; the clamp force, friction coefficient, radii, and surface count are the user's inputs.

Estimate. AHJ and licensed professional govern.

Field names used by the API: clamp_force_lbf, friction_coefficient, outer_radius_in, inner_radius_in, friction_surfaces, uniform_wear_torque_in_lbf, uniform_pressure_torque_in_lbf, max_pressure_psi

• Uniform wear T = F mu N (ro + ri)/2, the conservative design value; p max at riShigley Ch. 16
• Uniform pressure T = (2/3) F mu N (ro^3 - ri^3)/(ro^2 - ri^2), fresh rigid facingShigley Ch. 16
• Scope static torque from F; heat, wear life, band/cone brakes are separatescope of this tile