Types of Mechanical Power Transmission Systems: A Comprehensive Overview

Mechanical power transmission involves using different types of systems to transfer energy from one component to another without changing its nature.

When motion coming from a driving mechanical component is transferred to another without being changed, there is power transmission. In a mechanical power transmission system, the moving component transfers the energy to the receiving component. These two components can be in direct contact, but power can also be transmitted via an intermediary component.

Find out about the main types of mechanical power transmission systems in this article.

Gears

A gear system is composed of two or more toothed wheels that connect and interact with each other. It transmits a rotating motion.

This type of system is used to transmit a rotating motion between closely-spaced parts. The teeth of the gears interlock and move in concert.

Characteristics of gear systems

• There are many different types of gears (herringbone gears, helical gears, bevel gears, straight-cut gears, etc.)
• The gears’ position and teeth determine the orientation and precision of the motion transmitted by the system
• Gear systems are reversible and can be driven by any gear
• The direction of rotation changes from one gear to the next
• Using gears makes it possible to vary rotational speed
• Gears can be custom manufactured

Advantages and disadvantages of gear systems

Advantages

• Constant energy transmission, no slipping
• Compact systems that can transmit motion in small spaces
• Ideal systems for very high rotational speeds

Disadvantages

• Can generate noise and vibrations
• Require lubrication
• Manufacturing gears requires precision machining, which makes them a little more expensive
• Require precise adjustment
• Sensitive to impurities

Chain drive systems

In a chain drive system, a rotating motion is transmitted from one sprocket to another some distance away by way of a chain.

The system is driven by the links of the chain interlocking with the teeth of the sprocket. The two sprockets are the moving component and the receiving component, while the chain is the intermediary component.

Characteristics of chain drive systems

• Both sprockets rotate the same way
• The motion of the chain drive system is reversible
• The rotational speed of the system can be changed by adjusting the parameters of the sprockets, such as the diameter and the number of teeth

Advantages and disadvantages of chain drive systems

Advantages

• Low risk of slipping
• Can withstand high driving force

Disadvantages

• Can be a source of noise and vibrations
• The chain must always be kept well lubricated
• The chain tension must be readjusted often
• The rotational speed of the sprockets must be limited to avoid derailing the chain
• The axes of the sprockets must be perfectly parallel

Friction wheels

As their name suggests, friction wheel systems are made up of two or more wheels that are in contact with each other and transmit a rotating motion through friction.

In this type of drive system, the high friction generated by the rough surfaces of the wheels is harnessed to transmit the rotating motion.

Characteristics of friction wheel systems

• The direction of rotation changes from one wheel to the next
• The motion of the system is reversible
• The rotational axis of the wheels can be changed, from vertical to horizontal, etc.
• The rotational speed can be adjusted if needed

Advantages and disadvantages of friction wheel systems

Advantages

• Relatively quiet
• Generally low manufacturing cost

Disadvantages

• Friction wheels can slip
• Susceptible to degradation due to dirt and debris
• Assembling the system requires great precision

Worm drives

A worm drive system is composed of a worm screw with a helical thread and a worm wheel with teeth.

The helical thread of the screw interlocks with the teeth of the wheel to transmit motion. The term “endless screw” is sometimes used, because it can turn the wheel indefinitely.

Characteristics of worm drive systems

• A full rotation of the worm screw turns the wheel by one tooth
• The motion is not reversible because the worm wheel cannot drive it
• Since the worm wheel rotates perpendicularly to the worm screw, the system can change the rotational axis of the motion being transmitted
• This system can reduce the motion speed or increase the force within an object

Advantages and disadvantages of worm drive systems

Advantages

• Low risk of slipping
• The system remains in place and does not come loose when let go
• Provide very precise adjustment

Disadvantages

• The teeth of the wheel need to be adjusted precisely to fit the screw thread
• Difficult to build
• Sensitive to wear

Belt and pulley systems

Unsurprisingly, a belt and pulley system is composed of a pulley that rotates and pulls the belt, which in turn transmits the motion to a second pulley.

The system relies heavily on adhesion and friction between the components to transmit the rotating motion.

Characteristics of belt and pulley systems

• The adhesion of the belt to the pulleys is essential for the drive system
• Generally, the motion of the pulleys is reversible
• Open belt drives keep the same direction of rotation, while cross belt drives transmit a rotating motion in the opposite direction
• Using pulleys of different diameters can modify the rotational speed

Advantages and disadvantages of belt and pulley systems

Advantages

• Generally quiet
• No need for lubrication
• Effective at transmitting rapid motion
• With looser belts, this type of system can connect pulleys with axes that are not parallel

Disadvantages

• The belt may tend to slip off the pulleys
• The contact between the belt and pulleys must always be clean
• The life span of certain types of belts is limited

Braidwood Industries Ltd.: mechanical transmission system maintenance specialists

All of these mechanical systems can transmit motion and are often used in industrial equipment. Choosing the right system must be based on criteria such as the budget, available space, motion to be transmitted, desired speed, force required, etc.

It’s also important to remember that all of these mechanical transmission systems must be inspected frequently and maintained periodically in order to function properly. We are the leading gearbox maintenance specialists in Quebec!

Contact us to discuss your needs with our team.