LIEBHERR RING GEAR FOR FINAL DRIVE PLANETARY STAGE

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The ring gear for final drive planetary stage is a hollow-tooth annular element of the planetary final reduction stage in the driving axle of L-series wheel loaders, manufactured from case-hardened alloy steel 18CrNiMo7-6 with surface hardness HRC 58–62 on tooth flanks and a ductile core maintained at HRC 35–40 to resist impact loading. The teeth are precision-ground to AGMA Q11 accuracy class, ensuring consistent backlash control and low operating vibration. The ring gear meshes with planetary satellites, absorbing and reducing torque supplied via the drive shaft through the differential mechanism—typical planetary stage reduction is 15:1 to 25:1, delivering hub torques in the range of tens of kilonewtons-meters under nominal loader operating load. Dominant wear mechanisms are contact fatigue (case-depth spalling from the cemented surface layer) and abrasion from iron-particle contamination in the lubricant, leading to tooth-tip rounding and progressive backlash increase. Service indicators requiring replacement include whistling or whining from the axle at higher travel speeds, presence of ferromagnetic fines on the oil drain magnetic plug, and measurable excessive play at the wheel hub. Ring gear replacement must be performed as a matched set with the planetary satellites and sun gear of that stage—replacing only one element causes rapid fatigue damage to the new teeth bedding onto the worn profile. Post-installation procedure requires a minimum one-hour break-in period under partial load before full machine operation.

Compatible machines:

• L524-438
• L534-434
• L538-432