The structure of a CNC gear hobbing machine mainly consists of a bed, CNC system, key moving parts, feed system, and auxiliary devices. These parts work together to achieve high-precision gear machining.
Bed and Support Structure: The bed is the foundation of the entire machine tool, used to support and connect all components, ensuring overall rigidity and stability. High-end models often use high-strength cast iron or artificial marble beds to improve thermal stability and vibration resistance, reduce minor deformations during machining, and ensure accuracy.
CNC System (Core Control Unit): The CNC system is the "brain" of the gear hobbing machine, responsible for receiving machining instructions and precisely controlling the movement of each axis. Common systems include FANUC, SIEMENS, and GSK, which use electronic gearbox technology to achieve gear indexing and differential compensation, replacing traditional mechanical transmission chains, making machining more flexible and precise. Some systems support parametric programming; the operator only needs to input parameters such as the number of teeth and module for automatic operation, eliminating the need for manual writing of complex code.
Key Moving Components
Hob Spindle (B-axis): Drives the hob to rotate at high speed, performing the cutting motion. Modern equipment mostly uses direct-drive motors, eliminating worm gears or gear drives to achieve higher speeds and torque while reducing transmission errors.
Workpiece Spindle (C-axis): Drives the gear blank to rotate, forming a generating motion with the hob. Models using direct-drive technology can achieve more precise indexing control.
Feed System
Includes three main linear motion axes:
Radial Feed (X-axis): Controls the depth of the hob's cut towards the workpiece center. High-rigidity guideways and fully closed-loop control are commonly used to ensure consistent and precise feeds.
Axial Feed (Z-axis): Moves the hob along the workpiece axis, completing the cutting of the entire tooth width.
Tangential Cutting (Y-axis): Used to adjust the hob's axial position, facilitating multi-tooth machining or tool wear compensation. Controlled by a servo motor.