Types of Speed Gear Boxes

The layout of a gearbox machine tool is influenced by the dimensions and the physical layout of machine tool. The layout depends to a considerable extent on the purpose of the machine tool and its type and size.

The layout of the gearbox can be classified in two ways

1. Gearboxes build in the headstock and

2. Gear boxes in a separate headstock.

1. Gearboxes build in the headstock:

This type of gearboxes are employed in most medium size and heavy machine tool.

The Advantages are:

a. A compact spindle size.

b. Space economy.

c. Fewer housing type parts.

d. Cost economy.

e. Higher concentration.

f. Less assembly work.

The Disadvantages are:

a. The possibilty of transmission of the vibration from the gearbox to the spindle.

b. The spindle head is heated by the heat generated in the gearbox.

c. Difficulty of employing a flexible transmission to the spindle.

2. Gear boxes in a separate headstock:

The headstock and the gearbox may be designed as separate units connected by a belt transmission.

Advantages:

a. Headstock is not heated by the heat of gearbox.

b. Headstock is not directly affected by the vibration in the gearbox. And the if the spindle is relived of the belt tension.

c. The spindle runs smoothly at high speeds which is important to attain high grade of surface finish and longer tool life in finishing operations.

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