320 Swing Gearbox 1St Planetary Carrier Spider With Sun Gear Assy For Excavator parts

320 Swing Gearbox 1St Planetary Carrier Spider With Sun Gear Assy For Excavator parts

Product Overview

This complete first‑stage planetary carrier spider and sun gear assembly functions as the primary reduction core component fitted inside the swing reducer of 320 series medium crawler excavator. It directly receives torque input from the swing motor output end, executes initial speed reduction and torque amplification, and transmits driving power to the secondary planetary group to actuate upper‑structure slewing movement. The 320 series is one of the most widely operated 20‑ton excavator families across global construction, extensively deployed in earthmoving, quarry exploitation, road construction, building demolition and large‑site development projects. Under frequent forward‑reverse slewing cyclic impact loads, ageing oil seals and deteriorated gear lubricant permit metal wear particles and construction dust to penetrate the gearbox cavity, which causes spline galling, gear tooth pitting, carrier spider deformation and pin‑hole ovalization. Typical failure manifestations include harsh metallic grinding noise within swing gearbox, jerky and discontinuous cab rotation, insufficient initial swing torque, abnormal high temperature on reducer housing, and metallic sediment detected during swing gear oil replacement. Produced strictly in accordance with original forging drawings and gear engagement parameters, this aftermarket assembly supports direct drop‑in replacement and effectively avoids cascading damage to other expensive internal gearbox components.

Technical Specification

Core Advantages

1. Forged alloy construction adapted for 20‑ton excavator high‑impact swing load Carrier spider and matched sun gear are hot forged from premium alloy steel blanks. After carburizing quenching heat treatment, gear tooth surfaces and internal splines obtain high surface hardness while maintaining sufficient core toughness. The assembly can withstand sharp instant impact torque generated during swing startup, emergency stop and compound digging‑slew operations on mining and earthmoving sites, lowering risks of tooth chipping, spline abrasion and carrier spider distortion.
2. Pre‑tested gear meshing tolerance delivers stable initial slewing performance Every finished assembly undergoes tooth profile inspection and backlash measurement prior to shipment. Tightly controlled meshing clearance reduces transmission vibration and frictional grinding noise. When the excavator performs coordinated boom‑arm‑bucket plus swing compound movements, it maintains steady primary power transfer and prevents cabin stutter or jerky rotation triggered by poor gear fitting accuracy.
3. OEM‑duplicated mounting structure cuts overhaul downtime for 320 fleets Critical dimensions including carrier outer contour, sun‑gear spline specification, pin‑shaft hole layout and depth fully conform to original specifications. On‑site maintenance technicians can complete component swap directly without modifying gearbox housing or adjusting internal fitting gaps. For equipment rental fleets and local repair workshops supporting the large global 320 installed base, it shortens machine stand‑still hours and mitigates economic loss from swing system breakdown.
4. Stress‑relief annealing eliminates residual stress from hot forging Stress‑relief annealing removes internal residual stress generated in hot‑forging procedures, enhancing long‑term structural stability under repeated cyclic shock loads. Combined with high‑precision machining for pin shaft holes and bearing seats, it retards premature wear of mating planetary gears and bearings, extending the overall service life of the complete swing reduction unit.
5. Cost‑effective partial overhaul alternative for medium excavators Instead of purchasing a full expensive swing reducer unit, individually replacing the worn first‑stage planetary carrier and sun‑gear assembly helps end‑users control overhaul expenditure. It is highly suitable for machinery repair shops, equipment operators and global spare‑parts wholesalers serving the widespread 320 series installed base.

Manufacturing & Quality Control

Our production workshop focuses on planetary transmission spare parts for medium excavator swing gearboxes. Full‑process quality supervision covers raw‑material composition verification, forging appearance inspection, heat‑treatment hardness testing, gear‑tooth precision detection, spline dimension validation and sample no‑load running‑in test. Only fully inspected‑qualified products enter the packaging workflow. Finished assemblies are coated with anti‑rust preservation oil, wrapped with shock‑absorbing cushion materials and packed in export‑compliant fumigated wooden cases to avoid collision deformation and rust corrosion in long‑distance sea‑land logistics. We support bulk wholesale and stable batch supply; small trial orders are acceptable for worldwide purchasers.

Frequently Asked Questions

Q1: What abnormal phenomena indicate inspection or replacement of 1st planetary carrier and sun‑gear assembly? A: If your 320 excavator produces loud grinding noise inside swing gearbox, cabin rotates jerkily and intermittently, initial swing power drops obviously, reducer housing overheats, or metal particles are found in swing gear oil during oil‑drain maintenance, you should disassemble swing reducer for internal inspection promptly.

Q2: Will this assembly fit other excavator models? A: This component is engineered for the 320 series swing gearbox. Even if other models show partial similarities in outward appearance, internal gearbox configurations may differ greatly. Please double‑verify relevant OEM part numbers before placing order to prevent installation mismatch.

Q3: What essential installation notes during gearbox overhaul? A: Completely clear all metal debris and aged gear‑oil residue inside swing gearbox housing before installation. Meanwhile check wear condition of planetary gears, bearings and oil seals. After assembly completion, refill qualified swing gear oil, carry out low‑speed no‑load swing running‑in test before putting machine into formal construction work.

Q4: Warranty scope explanation A: Our warranty covers defects caused by raw‑material flaws and manufacturing errors. Damage resulting from foreign‑object intrusion, insufficient gear‑oil lubrication, severe overload impact and improper disassembly‑installation will not fall under warranty coverage. Please strictly comply with official service manual for swing gearbox overhaul procedures.