ناقل الحركة النهائي RD118-61290 لـ حفارة صغيرة Kubota KX121-3

TECHNICAL DATA SHEET: KUBOTA KX121-3 FINAL DRIVE
1. GENERAL IDENTIFICATION

Machine Model: Kubota KX121-3 (including ST/Super Tight versions)

Kubota Part Number: RD118-61290

OEM Manufacturer: Nachi-Fujikoshi

Components: Integrated Hydraulic Axial Piston Motor + Planetary Gearbox

2. PERFORMANCE SPECIFICATIONS

Motor Type: 2-Speed Variable Displacement Piston Motor

Reduction Ratio: High-ratio planetary reduction (typically around 1:40 to 1:50)

Max Operating Pressure: 24.5 MPa (3,553 PSI)

Torque Output: Engineered for high breakout and climbing force

Travel Speeds: * Low Speed: Max torque for trenching/climbing

High Speed: Faster tracking across level job sites

3. MECHANICAL INTERFACE (INSTALLATION DATA)

Sprocket Mounting: 9-Bolt or 12-Bolt pattern (Verify the bolt circle diameter on your existing sprocket).

Frame Mounting: Circular flange with standardized bolt holes for the KX121-3 undercarriage.

Hydraulic Ports:

A & B Ports: Main flow for Forward/Reverse travel.

P Port (Pilot): 2-speed shifting signal.

D Port (Drain): Case drain return to the hydraulic tank.

4. INTERNAL REPAIR COMPONENTS
If you are performing a rebuild, these are the critical sub-assemblies to inspect:

Rotary Group: Cylinder block, 9 pistons, set plate, and valve plate.

Planetary Gear Set: 1st, 2nd, and 3rd stage sun gears and planet gears.

Floating Seal (Duo-Cone): Prevents gear oil from leaking out and dirt from entering.

Main Bearings: Large angular contact bearings that support the weight of the machine and the tension of the tracks.

5. MAINTENANCE & INSTALLATION PROTOCOL

Gear Oil Type: SAE 90 or 80W-90 Gear Oil (API GL-4 or GL-5).

Gear Oil Change Interval: Initial change at 250 hours, then every 1,000 hours thereafter.

Case Drain Safety: CRITICAL. Ensure the case drain line is not restricted. A blocked drain line will cause the internal motor pressure to spike, blowing out the shaft seal or damaging the motor housing.

Installation: Ensure the mounting surfaces are perfectly clean and bolts are torqued to Kubota factory specifications.