Gear hobbing, that's how gears are made

Writer： admin Time：2024-11-23 10:47:18 Browse：5℃

The tooth surface of internal and external gears or racks processed by hobbing or forming method with a hobbing cutter is called hobbing.

From the principle analysis of the gear hobbing process, the gear hobbing tool is equivalent to a pair of cylindrical gears with parallel axes meshing with each other. 

A gear hobbing cutter is essentially a gear with front and rear angles and cutting edges.

Sports:

(1) The up and down reciprocating motion of a cutting hobbing tool. (2) The correct meshing relationship should be maintained between the gear hobbing tool and the workpiece during gear splitting. 

The gear hobbing tool reciprocates once, and the workpiece is relative to the tool in terms of indexing

The arc length rotated on the circle is the circumferential feed rate during machining, so the meshing process between the tool and the workpiece is also known as the circumferential feed process. 

(3) When performing radial feed motion gear hobbing, in order to gradually cut to the full tooth depth, the gear hobbing tool should have a radial feed rate fr.

(4) When the hobbing tool moves back and forth up and down, the downward direction is the cutting stroke. In order to avoid tool scratches on the machined tooth surface and reduce tooth wear, 

when the hobbing tool moves upward,

The workbench drives the workpiece to exit the cutting area for a distance (radially). During the working stroke of the gear hobbing cutter, the worktable returns to its original position.

Gear hobbing can process both straight and helical teeth; Hobbing can also process straight and helical teeth, but the efficiency of hobbing is higher.

Compared with gear hobbing, gear hobbing has its own characteristics in terms of machining quality, productivity, and application range.

When cutting gears with large modulus, the hobbing speed is constrained by the reciprocating inertia of the hobbing tool spindle and the rigidity of the machine tool; 

The cutting process also incurs time loss due to idle travel, resulting in lower productivity compared to gear hobbing.

Only when processing gears with small module, multiple teeth, and narrow tooth width, the productivity of gear hobbing is higher than that of gear hobbing