Girth Gear/Bull Gear/ Gear Ring

A girth gear, also known as a bull gear or gear ring, is a large-diameter gear mounted on the outer circumference of heavy-duty rotating equipment such as ball mills, rotary kilns, and dryers. It serves as a critical component in transmitting torque and rotational motion from a driving system (e.g., pinion gear or motor) to the main drum or shell of the machinery.

Materials Used for Girth Gears

Cast Steel: Provides excellent strength and wear resistance.

Commonly used for heavy-duty applications.

Forged Steel: Offers superior toughness and resistance to fatigue.

Ductile Iron: Combines strength with cost-effectiveness, suitable for moderate-duty applications.

Alloy Steel: Enhanced wear resistance and mechanical properties for demanding environments.

Ni-Hard and White Cast Iron: Used in highly abrasive conditions.

Girth Gear/Bull Gear/ Gear Ring Application Range

A gear ring is widely applied in various industries, including cement manufacturing, mining, heavy-duty lifting equipment, light industry machinery, chemical processing, transportation systems, construction machinery, and other mechanical deceleration systems.

Advantage of Gear

1.Great load-bearing capacity,and extended durability.

2.High precision,large diameter and significant module. . 

3.Steady transmission,Minimal impact

4. forging or casting according to the customer’s requirements

5.Ultrasonic inspection will be conducted to ensure that the materials are free from pores, holes, and cracks.

Specification as Below

Manufacturing Process for Girth Gears

Casting: Large gears are typically made using sand casting to achieve the required size and shape.

Forging: Smaller, high-strength gears may be forged for better structural integrity.

Machining: Precision machining ensures accurate tooth profiles and surface finishes.

Heat Treatment: Enhances mechanical properties such as hardness, toughness, and wear resistance.

Inspection: Non-destructive testing (NDT) methods like ultrasonic or magnetic particle testing ensure defect-free products.

Maintenance of Girth Gears

Regular Inspection: Check for cracks, wear, and misalignment using visual and non-destructive testing methods.

Lubrication: Proper lubrication reduces friction, wear, and operational noise.

Alignment Checks: Ensure proper alignment between the girth gear and pinion to prevent uneven wear.

Surface Cleaning: Remove debris and contaminants that may accelerate wear.

Timely Repairs: Address minor issues promptly to avoid costly failures.