Komatsu PC120-6 Swing Gearbox 2nd Planetary Carrier Spider With Sun Gear Assy For 203-26-61130 203-26-61170 203-26-61180

Komatsu PC120‑6 Swing Gearbox 2nd Planetary Carrier Spider With Sun Gear Assy For 203‑26‑61130 203‑26‑61170 203‑26‑61180

Product Overview

This complete second‑stage planetary carrier spider and sun gear assembly acts as the secondary torque reduction module housed inside the swing reducer for Komatsu PC120‑6 12‑ton midi crawler excavator. It accepts decelerated torque output delivered from the first‑stage planetary set, carries out further speed reduction and torque amplification, and outputs powerful driving force to drive upper‑structure slewing movement. This excavator model is widely applied in urban municipal reconstruction, trench digging, housing foundation earthwork, highway maintenance and medium‑sized quarry sites. Under continuous alternating slewing impact loads, deteriorated oil seals and degraded swing gear oil will permit grit, construction dust and metallic debris entering gearbox inner chamber, bringing about spline abrasion, gear tooth pitting, carrier spider distortion and pin‑hole out‑of‑round failure. Common fault performances contain harsh metallic grinding sound inside swing gearbox, choppy cabin rotation, insufficient swing output torque, excessive temperature rise of reducer housing, plus metal residues found while draining swing gear oil. Produced strictly in accordance with original forging blueprints and gear engagement parameters, this premium aftermarket assembly supports direct drop‑in installation, effectively protects other high‑cost internal gearbox components from secondary destructive damage.

Technical Specification

Core Advantages

1. Forged alloy structure resisting heavy secondary‑stage transmission shock load The carrier spider and matched sun gear are hot‑forged from high‑grade alloy steel blanks. After carburizing and quenching processing, gear tooth faces and inner splines achieve high surface hardness meanwhile maintain good core material toughness. It can bear heavy alternating impact torque generated during frequent digging‑slewing compound movements, greatly lower failure risks including tooth chipping, spline scratch and carrier deformation under harsh dusty construction environment.
2. Strictly inspected gear meshing tolerance delivers steady slewing operation Every finished assembly will implement tooth profile detection and backlash testing before ex‑warehouse. Precisely controlled meshing clearance reduces transmission vibration and friction grinding noise. When the machine executes compound actions of boom lifting, arm crowding, bucket curling together with swing, it keeps stable power transmission and prevents cabin jitter or jerky rotation triggered by poor gear matching precision.
3. OEM‑duplicated mounting dimension cuts on‑site repair man‑hour cost Key critical dimensions covering carrier outer outline, sun gear spline parameters, pin shaft hole layout and depth are fully consistent with original OEM standards. Field service mechanics can finish component replacement directly, no need for gearbox housing modification or manual fitting‑gap adjustment. For rental equipment companies and local repair workshops, it minimizes machine downtime and avoids economic losses caused by project halt resulting from swing system breakdown.
4. Stress‑relief annealing removes forging inner stress Stress‑relief annealing procedure eliminates residual internal stress produced in hot forging progress, improving long‑term structural stability under cyclic shock loads. Cooperated with high‑precision machining for pin shaft holes and bearing mounting seats, it delays premature wear of matched planetary gears and bearings, prolonging total service lifespan of the whole swing reduction unit.
5. Cost‑saving partial overhaul solution for repair shops and equipment owners Instead of purchasing the complete expensive swing reducer unit, replacing only the worn second‑stage planetary carrier & sun gear assembly helps end‑users control overhaul budget. This solution fits perfectly for machinery repair workshops, equipment operators and global Komatsu midi excavator spare‑parts wholesalers.

Manufacturing & Quality Control

Our production plant focuses on planetary transmission spare parts for Komatsu 10‑14 ton excavator swing gearboxes. Full‑flow quality management includes raw‑material composition check, forging appearance inspection, heat‑treatment hardness verification, gear tooth accuracy testing, spline dimension confirmation and sample no‑load running‑in test. Only fully qualified assemblies can enter packaging procedure. Finished goods are coated with anti‑rust protective oil, wrapped with shock‑absorbing cushion material and packed in export‑standard fumigated wooden cases, avoiding collision deformation and rust during long‑distance sea‑land multi‑modal transport. We support large‑volume wholesale, stable batch supply; small trial orders are welcomed for global buyers.

Frequently Asked Questions

Q1: What abnormal phenomena indicate inspection or replacement of 2nd planetary carrier and sun‑gear assembly? A: If your Komatsu PC120‑6 excavator generates loud grinding noise inside swing gearbox, cabin rotates intermittently and jerkily, swing output power drops significantly, reducer housing overheats, or metal particles are discovered in waste swing gear oil during oil change maintenance, you ought to disassemble swing reducer for thorough internal inspection without delay.

Q2: Will this assembly fit other excavator models? A: This spare part is specially designed for Komatsu PC120‑6 swing gearbox. Although PC100‑6 and partial PC130‑7 share similar outer appearance, inner gearbox structure may exist differences. Please double‑check OEM part numbers 203‑26‑61130, 203‑26‑61170, 203‑26‑61180 before submitting your order to prevent installation mismatch.

Q3: What essential installation notes during gearbox overhaul? A: Thoroughly clear all metal scraps and residual old gear oil inside swing gearbox housing ahead of installation. Meanwhile check wear status of planetary gears, bearings and oil seals. After finishing assembly work, refill qualified swing gear oil, perform low‑speed no‑load swing running‑in test before putting excavator into formal construction operation.

Q4: Warranty scope explanation A: Our warranty policy covers defects originating from raw‑material flaws and manufacturing errors. Damage caused by foreign‑object invasion, insufficient gear‑oil lubrication, severe overload impact and improper disassembly‑installation operation will not be included within warranty coverage. Please strictly follow Komatsu official service manual while performing swing gearbox overhaul work.