In production engineering, gear hobbing is a _____.

Question

Question

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RRB JE CBT 2 (Mechanical Engineering) ReExam Official Paper (Held On: 04 Jun, 2025)

Answer 1

Explanation:

Gear Hobbing

Gear hobbing is a machining process used for cutting gears, splines, and sprockets. It is one of the most widely used methods in gear manufacturing and is especially suitable for producing high-quality gears with precision. The process involves the use of a specialized cutting tool called a hob, which is a cylindrical cutting tool with helical teeth. The hob and the workpiece (gear blank) rotate in a synchronized manner, allowing the hob to cut teeth into the blank progressively. The process is efficient, versatile, and suitable for mass production of gears.

Working Principle:

In gear hobbing, the hob rotates at a high speed while the gear blank is mounted on a spindle and rotates at a specific speed ratio relative to the hob. The hob's teeth cut into the blank as the two rotate together, shaping the gear teeth. The synchronization between the hob and the blank ensures the correct tooth profile and spacing.
The cutting operation in gear hobbing is continuous, which makes it faster and more economical compared to other gear manufacturing processes, such as gear shaping. The hob's design and rotational speed determine the gear's characteristics, such as the number of teeth, module, and pressure angle.

Applications of Gear Hobbing:

Manufacturing spur gears, helical gears, and worm gears.
Production of splines and sprockets.
Used in the automotive, aerospace, and industrial machinery sectors for producing precision gears.
Ideal for high-volume production due to its efficiency and speed.