Heavy-Duty Double Helical (Herringbone) Gear Shafts for Rolling Mills
Product Description
The double helical gear shaft, or herringbone pinion, is the workhorse component inside a rolling mill's main gearbox or pinion stand. It is responsible for transmitting immense torque from the motor to the mill rolls, withstanding extreme shock loads and continuous operation. The reliability of this single component is critical to the entire production line.
Yile Machinery forges and machines high-precision herringbone gear shafts engineered for maximum strength, durability, and operational life in the harshest steel mill environments.
Manufacturing Process: Forging Strength and Precision
The performance of a mill pinion is determined by the quality of its manufacturing process. We follow a rigorous, multi-stage production protocol to ensure superior mechanical properties:
High-Quality Forging: We begin with premium alloy steel ingots (e.g., 42CrMo, 34CrNiMo6, 18CrNiMo7-6). The steel is forged to create a refined internal grain structure, eliminating porosity and vastly increasing its toughness and fatigue resistance compared to standard bar stock.
Heat Treatment (Quenching & Tempering): After rough machining, the shaft undergoes a crucial heat treatment process. Quenching and tempering develops the optimal combination of high surface hardness for wear resistance and a tough, ductile core to absorb shock loads without fracturing.
Precision Machining & Gear Cutting: The final stage involves finish machining of the shaft journals and the precise cutting of the double helical gear teeth using advanced CNC gear hobbing or grinding machines. This ensures perfect tooth profile, smooth engagement, and quiet operation.
The Double Helical Advantage
The herringbone gear design is superior for high-torque applications for several key reasons:
High Torque Capacity: The opposing helix angles on the gear face allow for multiple teeth to be engaged simultaneously, distributing the load and allowing for the transfer of enormous power.
Smooth, Quiet Operation: The gradual engagement of the V-shaped teeth results in a much smoother and quieter power transmission compared to spur gears.
No Axial Thrust: Unlike single helical gears which generate axial forces, the opposing helices of a herringbone gear cancel these forces out. This eliminates the need for complex thrust bearings, simplifying the gearbox design and improving reliability.
Key Features & Technical Specifications
Material: Forged alloy steels including 42CrMo, 35CrMo, 34CrNiMo6, 18CrNiMo7-6, and other custom grades.
Manufacturing: Forged + Heat Treated (QT) + Precision CNC Machined.
Gear Type: Double Helical / Herringbone.
Application: Rolling Mill Gearboxes, Pinion Stands, Ship Propulsion, and other heavy-duty industrial drives.
Custom Manufacturing: Produced according to customer drawings and technical specifications.
Inspection: All shafts are subject to rigorous quality control, including UT (Ultrasonic Testing), MT (Magnetic Particle Testing), and dimensional checks.
Get a Quote for a Forged Pinion Shaft
Ensure the reliability of your mill drive. Send us your technical drawings and material requirements to receive a competitive quotation for a custom-manufactured herringbone gear shaft.