Inline Gear Reducers

Inline gearboxes are classified as parallel or coaxial, and each uses a distinctive gear arrangement with its own set of advantages and disadvantages.

How Inline Gear Reducers Work

A motor rotates the input shaft at a set speed, and a sequence of reduction gears slows the rotational speed. Depending on the reduction ratio, the diameter and circumference of the gears vary. A gear revolves on an input shaft, which turns a larger gear. The second gear takes longer to rotate the full distance due to its larger circumference and does not turn as quickly as the little first gear. Multiple gears can be connected in series, and the output shaft connected to the final gear to achieve the desired speed reduction.

Although greater performance speed reducers are available, reduction ratios typically range from 5:1 to 200:1. A gearhead is a gear reducer that is directly mounted on a motor; a gearbox is a gear reducer that is linked with the shaft and mounted elsewhere. Units that are installed on the shaft are also available. Inline gear reducers can be used in conjunction with other reducers to satisfy specific needs, and they come in a range of styles to fit a variety of mountings and setups.

Types of Inline Gear Reducers

The types of inline gear reducers include:

Parallel Inline Gear Reducers

The input and output shafts of a parallel inline gearbox are oriented in the same direction but offset by a certain distance, resulting in shaft axes that are parallel to each other. Spur, helical, and double helical gear types are commonly used in parallel gearboxes.

Helical Gear Reducers

Helical gears contain teeth that run diagonally, which increases the meshing surface area between gear teeth and the number of teeth in contact, allowing the gearbox to handle more torque. Helical gears produce thrust forces along the shaft axis, which can put significant stress on bearings. While helical gears have far better all-around performance characteristics than spur gears, with far higher torque capability and somewhat quieter operation, they produce thrust forces along the shaft axis, which can put significant stress on bearings. Depending on the pressure, this may necessitate unique techniques to sustain the load, and their power transmission capability is reduced compared to double helical gears.

Double Helical Gear Reducers

Helical gears generate thrust, which can shorten the life of gearboxes. Double helical gears use a gear that looks like two opposing helical gears positioned side by side to deal with the thrust force created. Twice helical gear systems double the high torques of helical gears while retaining the benefits of helical gears.

Spur Gear Reducers

The simplest gear is a spur gear, which has straight teeth that protrude radially from the gear center. Despite their inexpensive cost, spur gear systems have a lot of noise, backlash, and torque transmission capabilities. In addition, because of the small surface area of the gear teeth, they are subjected to significant stresses; therefore, this gear system is designed for low-speed, low-torque applications.

Coaxial Inline (Planetary) Gear Reducers

A coaxial inline gearbox's input and output shafts are aligned along the same line with no position offset, allowing the motor, gearbox, and load to revolve around the same axis. Planetary gear systems are used in these gearboxes. A planetary gear system is a relatively sophisticated gear design that uses a collection of gears (referred to as "planet" gears) that rotate around a single gear in the center (referred to as the "sun" gear).

This gear design enables high reduction ratios in a compact dimension by transmitting great torque along a straight axis with perfect balance. Planetary gearboxes are great for improved acceleration and high precision applications because they can be coupled in stages to obtain high reduction ratios. They also have little backlash.