LIEBHERR SPRING-APPLIED MULTI-DISC DRIVE BRAKE

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The spring-applied multi-disc drive brake is an integral assembly of the final drive transmission in Liebherr tracked and wheeled machines, serving simultaneously as a parking and service brake. The brake housing is manufactured from alloy steel 42CrMo4 (heat-treated to 28–34 HRC), while the friction discs are made from case-hardened 16MnCr5 steel hardened to 58–62 HRC, with nominal working thickness of 3.5 mm and permissible wear of 0.4 mm per side. The multi-disc pack operates in an oil bath (wet brake), which mitigates fretting corrosion on clutch surfaces and abrasive wear of friction linings under nominal spring pressure of 180–220 kN. Brake release occurs hydraulically at operating pressure of 35–45 bar, with holding torque exceeding 12,000 Nm at the output shaft. Belleville springs manufactured from stainless spring steel maintain clamping force stability across the temperature range of –40 °C to +120 °C, which is critical for operation in extreme conditions. Contact fatigue of the discs manifests as pitting and edge micro-cracking—detected during penetrant inspection—and constitutes grounds for complete pack replacement without selective regeneration. Liebherr recommends replacement of the brake as an assembly without separation of spring and disc components.

Compatible machines:

• LR632-393
• LR632B-393
• PR732-350
• PR732B-350
• PR732BL-412
• PR732BM-351
• PR732L-412
• PR732M-351

Fits travel reducers / final drives:

• 500/555
• FAT 500P595D

Travel-system component for LIEBHERR construction machinery — used in travel reducers and final drives of crawler machines (excavators, crawler loaders, dozers) as well as in drive axles and wheel-hub planetary reductions of wheeled machines (wheel loaders, wheeled excavators). Industry synonyms: travel drive, final drive, drive axle, traction drive, travel reducer, planetary final drive, drive reducer, wheel-hub reduction.