3109158 GEAR;SUN HITACHI for ZX75US-5A/4TNV98

The Central Drive of Your Planetary System – Precision‑Engineered to Distribute Torque and Enable Speed Reduction.
The sun gear is the central drive gear within every planetary reduction system of your Hitachi excavator—whether in the final drive, swing device, or travel motor. As the primary input component, it transmits rotational force from the motor or drive shaft directly to the surrounding planetary pinions. This genuine Hitachi sun gear is manufactured to exact OEM specifications, ensuring the precise tooth profile, helix angle, and dimensional accuracy required for your specific planetary gearbox application. Trust this gear to deliver smooth, balanced load distribution across multiple planetary gears, enabling efficient power transmission and reliable speed reduction under the most demanding operating conditions.

Premium Metallurgy and Precision Manufacturing – Built to Withstand Extreme Torque and Continuous Operation.
Manufactured from high‑strength, case‑hardened alloy steel and precisely heat‑treated, this genuine sun gear achieves a hard, wear‑resistant surface that resists pitting, spalling, and abrasive wear, combined with a ductile core that absorbs shock loads and resists tooth fracture. Precision‑ground tooth flanks and accurately cut splines ensure perfect meshing with mating planetary pinions and drive shafts. Every sun gear is produced to meet Hitachi’s stringent quality standards for tooth geometry, hardness depth, and dimensional accuracy, ensuring consistent performance and extended service life in the most demanding excavation, demolition, and material handling applications.