Sumtiomo SH200 Swing Gearbox 2nd Planetary Carrier Spider With Sun Gear Assy For Excavator Parts

Sumitomo SH200 Swing Gearbox 2nd Planetary Carrier Spider With Sun Gear Assy For Excavator Parts

Inside the Sumitomo SH200 swing reducer, the second‑stage planetary carrier spider and sun gear assembly is where the final multiplication of torque happens before power reaches the ring gear and drives the upper structure around. It takes the already‑reduced output from the first stage and steps it down again, which means it routinely operates under the highest torque in the entire swing drive chain — and under the greatest stress when the machine digs, lifts and swings in quick succession. On a 20‑ton class unit working in infrastructure and rental fleets, that constant alternating load gradually takes its toll: pin bores ovalize, the carrier web distorts, and sun gear teeth pit or chip once oil contamination sets in. Operators typically notice it as a deep grinding note during rotation, a lag when starting a swing, and a progressive loss of turning power that worsens as the gearbox warms up. This aftermarket assembly is manufactured to the original drawings so the worn second stage can be renewed on its own — a targeted repair that protects the ring gear and avoids the expense of a complete reducer.

Technical Specification

Core Advantages

1. Built for the highest‑torque position in the drive chain Because the second stage multiplies torque a final time, its parts see the peak loads of the whole swing system. The carburized, case‑hardened sun gear and forged carrier are engineered for exactly this duty, resisting tooth chipping and spline wear where lighter‑grade parts fail early.
2. Distortion resistance that protects the ring gear above all A bent carrier spider throws the planet set out of line and grinds against the ring gear — an expensive failure that can cost a full reducer. Stress‑relieved forging and stable pin‑hole geometry keep the spider true, so the ring gear meshes evenly and stays within service life.
3. Quiet final drive with controlled gear clearance The sun gear and planet profiles are ground and backlash‑checked, keeping the final stage running with a clean, even note. That removes the deep growl and knock that worn second‑stage gears produce, which matters on machines working close to crews and buildings.
4. A measured, documented fit for confident installation Key dimensions are verified against the OEM drawing and recorded before dispatch, so the workshop can install with confidence. Direct interchangeability means no machining, no custom shims and no extended downtime during the changeover.
5. Flexible supply that fits both one‑off repairs and fleet programmes Whether you need a single unit for one machine or a stock batch for a workshop servicing several SH200s, we can match the quantity — with samples available first for shops testing a new supplier.

Manufacturing & Quality Control

Steel is verified by composition check before forging, and each stage of processing — forging, annealing, machining, carburizing and grinding — is recorded against the batch. Final acceptance includes spline gauging, pin‑hole measurement, tooth profile and hardness checks, with sample running‑in to confirm quiet operation. Finished units are rust‑protected, cushioned and shipped in fumigated export crates. Trial orders, repeat batches and scheduled wholesale supply are all supported.

Frequently Asked Questions

Q1: How do I confirm my machine needs the second‑stage assembly rather than the first?

A: The symptoms overlap, so the reliable way is to open the reducer during inspection and compare the worn parts against both drawings. If the damage is in the final planet set and its sun gear, this is the assembly you need.

Q2: Can the carrier and sun gear be ordered separately?

A: Yes, on request. If only one of the two is worn, we can supply the single part — but many customers prefer the matched pair to guarantee fresh mating surfaces.

Q3: Is the spline compatible with the swing motor on early‑build SH200 machines? A: Our standard unit follows the mainstream SH200 configuration. Early‑build machines can differ, so please provide your machine serial number and, if possible, the old part number so we can confirm compatibility.

Q4: What is your lead time for a bulk order?

A: Stock items can ship within days; production batches depend on quantity and are confirmed at order time. We will give you a clear dispatch date before you commit.