The Composition and Working Principle of Reduction Gearbox

internal structure of worm reduction gearbox

Figure 1: Worm reduction gear in section on stand.

Gearbox, also called reducer or gear reducer, is a widely applied reduction transmission mechanism equipment, composed of two or more gears.

1. The Composition of Reduction Gearbox

Structures of reduction gearbox are as follows:

1.1 Body and Hood

Body and hood of reduction gearbox are the support and containment parts of the transmission parts in reducer, with intricate structures. Its body is required to have the great quality of rigidity, vibration damping, and tightness.

When produced in small scales, gearbox body and hood are made of gray cast iron material, cast by manual molding, or made of carbon structural steel and welded by manual electric arch. While in mass production, they are made of gray cast iron, and cast by machine molding method.

1.2 Shaft, Gear Shaft, and Gear

Shafts, gear shafts and gears are significant transmission parts in reducer. The shaft parts of shafts and gear shafts, subject to combined action of bending short force and twist short force, are required to have better comprehensive mechanical properties.

When produced in single piece, they are made of medium carbon steel (45 steel), cast by free forging method or loose tooling forging method, and can be turned from medium carbon steel bar. While in mass production, medium carbon steel forging method is used to cast.

1.3 Rolling Bearing

The function of bearing end cover is mainly to prevent the occurrence of bearing tampering, and offer protection. When produced in single piece or small scales, it is cast by manual handing, made of gray cast iron, or turned from carbon structural steel round steel. While in mass production, it is cast by gray cast iron machine molding.

Parts including body and hood, shaft, gear shaft, gear, rolling bearing, and bolt and nut are essentially fundamental components of reduction gearbox

Figure 2: Basic components of reduction gearbox, including big and small gears, bolt, transmission shaft, end cap, bearing, upper and lower body.

1.4 Bearing and Cover

1.5 Bolt and Nut

The function of bolts and nuts is to fix the gearbox body and hood. Bolt shafts are subject to vertical (axial) tensile stress, bending stress, transverse shear stress.

2. Working Principle of Reduction Gearbox

Gear reducer aims to decrease speed by gears transmission at every level. The reducer is composed of gear pairs at every level. For example, the purpose of speed reduction can be achieved by small gears driving large gears, and multi-stages structure like this can greatly reduce the speed.

Gear reducer is generally used in transmission equipment that is low speed and high torque. Common gear reducer also has several pairs of gears meshing with same principles to achieve the ideal speed reduction effect. The ratio of the number of teeth of large and small gears is transmission ratio. With the thriving development of gear reducer, it has been used in an increasing number of enterprises.