Common belt failures

The belt, in the context of power tools, plays a crucial role in ensuring the efficient transmission of motion and power between different parts of a machine. This allows for a variety of tasks, from cutting to sanding to drilling. Its operation is based on a simple but ingenious principle: it connects two pulleys, one driving (which supplies the energy) and the other receiving (which receives the energy). In this article, we will explore common belt failures in detail.

The operation of the belt

To ensure the proper functioning of the belt, it is important to maintain the correct tension from the start of its use. This initial tension ensures optimum adhesion between the drive belt and the pulleys, which contributes to the efficient transmission of motion through the machine. It is often necessary to add a mid-range system or an additional tensioner to adjust the initial tension of the belt and compensate for its elongation over time.

When the machine is running, the belt slips on the surface of the pulley, which may cause a slight fluctuation in the transmission ratio of the movement. This situation is common for most types of belts, with the exception of timing belts which work with a precision coupling mechanism.

The characteristics of the belt

Compared to other transmission modes, such as chains or gears, the belt offers obvious advantages that greatly improve the use of power tools:

• It's flexible so you can place the motor and receivers wherever you want
• It is quiet even at high speeds
• Effectively dampens transmission jerks, shocks and vibrations
• It is economical because the belt replaces gears, countershafts, bearings and rigid gears

Types of belts at ITAFRAN

V-belts

Belt functionstrapezoidal most commonly used:

• Predominance in use due to their low cost
• Cost-effective solution for power transmission
• Price and performance optimization
• Excellent ratio between price and transmitted power
• Suitable for optimal speeds, ranging from medium to highs
• Wide range of use for different powers
• Generally quiet, however raw edge belts can generate noise
• Used very frequently and are the most common choice for power transmission

Advantages of V-belts:

• Effective hold of the strap in its groove
• Higher power transfer for the same applied voltage
• Ability to operate at speeds up to 33 m/s
• More compact size compared to flat belts

Toothed belts 

Main functions of timing belts:

• Transmission of power from a motor shaft to a driven shaft
• Precise meshing with pulley or gear teeth to transfer torque and rotational speed efficiently
• Precise synchronization between motor and driven shafts for perfect coordination in various systems such as combustion engines, machine tools and automation
• Reduction of noise and vibrations thanks to the smooth meshing of the teeth of the toothed belt
• Lightweight and simple compared to other transmission methods

Advantages of timing belts:

• No need for lubrication
• High yield
• Shock absorbing capacity due to elasticity
• Fewer maintenance requirements
• Affordable cost

Courroies POLY-V

Functions of specific belts in very large series:

• Very quiet operation
• Small footprint with minimal spacing between elements

Advantages of specific belts in very large series:

• Long life expectancy
• Superior durability compared to V-belts
• Excellent soundproofing during use
• Possibility of obtaining high reduction ratios
• Primarily used in mass-produced applications such as appliances, automotive, conveyors and power tools
• Some variants are elastic and install easily

When should belts be serviced?

When it comes to power tools, belts wear out quickly. It is very important to regularly check:

• Loss of elasticity : If the belt is installed incorrectly on the pulley, it may lose its elasticity and slip
• Lack of tension : a badly tensioned belt can produce a hissing sound, which means less grip
• Natural wear : Age and heavy use cause belt wear, which can lead to breakage and engine damage.

 Belt maintenance should be done regularly, with a quick visual and sound inspection once a month and a thorough inspection of the unit with a complete driveline shutdown once or twice a year.