SBD-A is the upgraded variant of the original SBD safety brake family. The fail-safe caliper mounts on the drum shaft, clamps the brake disc through friction pads, and is held in the "braked" state by a disc-spring pack; pressurised oil from the HPU retracts the piston and releases the brake. It is the standard low-speed-shaft safety brake on Chinese-made cranes, complying with JB/T 10917-2008 (disc/caliper brakes).
| Code | Meaning | Value for this unit |
|---|---|---|
| SBD | Safety Brake, Disc type (spring-applied) | SBD family |
| 125 | Rated total clamping force | 125 kN (≈ 90 kN effective braking force) |
| A | Mounting / structural version | A-type (dimensions A, C, d1, d2 per table) |
| -D×t | Disc diameter × thickness (order suffix) | e.g. -1600×30 → Ø1600 / 30 mm |
| I / II | Mounting-version suffix | I-version or II-version installation |
| R / L | Release / wear limit switch option | Optional open-position & pad-wear limit switches |
Order-mark example (from manufacturer standard):
SBD250-A-1600×30 IRL = rated clamping force 250 kN · A-type · I-version mount · release limit switch · disc Ø1600 mm · disc thickness 30 mm.
For SBD125-A, substitute 125 and the actual disc size: SBD125-A-D×t [I/II] [R/L].
Technical Data
| Parameter | SBD125-A | Note |
|---|---|---|
| Total clamping force | 125 kN | Rated; set by adjusting-nut + piston-rod protrusion L |
| Braking (effective) force | 90 kN | Force available at friction diameter |
| Cylinder working pressure | 9 MPa (≈90 bar) | HPU must deliver ≥ this to release |
| Oil volume to release | 90 mL | Per opening; size the HPU accordingly |
| Released (open) clearance | 0.75 – 1.5 mm | Uniform both sides; auto-compensated as pads wear |
| Brake disc diameter D | Ø800 – Ø1800 mm | d1 = D − 135 (mm); d2max = D − 270 |
| Friction coefficient μ | 0.35 (calculation) / 0.36 (nominal) | Non-asbestos hard lining |
| Braking torque M | M = μ × d1 × F (N·m) | See §4 calculation |
| Weight | 195 kg | Caliper assembly |
| Duty / response | Fast closing, short engage time | Emergency / parking duty; not continuous friction service |
| Mounting bolts | Foundation bolts (see dims A, C) | Torque to specification |
Working conditions
Ambient temperature: −20 ℃ to +40 ℃ (some sources −25 ℃; confirm per supplier / tropical option)
Relative humidity ≤ 90%, no condensation; altitude ≤ 2000 m
No strong corrosion, no flammable/explosive atmosphere at the brake - standard SBD is NOT explosion-protected; use BYWZ5 / DYW / Ed.Ex series for hazardous zones
