TechArchive

Original article date: April 2000

Are you getting the best performance and lifespan out of your belt drive? We offer a few installation tips

Although comparatively old in principle, today’s belt drive is an extremely efficient method of transferring power between prime mover and machinery. Ongoing refinements of materials and processes have meant ever higher performance standards.

Of course the maximum benefit from these advances can only be obtained if the belts are correctly installed. Following a few standard installation steps will ensure optimum performance is combined with a long and trouble-free life.

Before assembling the drive, check the pulley grooves are free from scores or sharp edges, and all dimensions conform to the relevant standard.

The taper lock bush is your starting point when it comes to assembly and installation. Drive installation is a straight forward job with the taper lock.

Good alignment of pulleys prior to belt installation is important to avoid belt flank wear. Common alignment faults include shafts not being parallel (Figure 1b), shafts not being in correct alignment although they appear parallel when seen from above, and shafts being in parallel alignment whilst the pulleys themselves are not (Figure 1c). In short, both shafts and pulleys must be parallel in alignment (Figure 1a).

When the pulleys have been correctly positioned on the shafts, the belts can be installed to complete the drive. The drive centre distance should be reduced prior to installation of the belts so that they may be fitted without the use of force. Under no circumstances must belts be prised into the grooves. Belts and pulley grooves can easily be damaged by using sharp tools to stretch the belts over the pulley rim. In addition, correct guidelines should be followed for installation allowance and take-up allowance.

Where guards are necessary it is desirable to use the mesh type to permit adequate ventilation.

If tensioning pulleys are to be used on wedge-belt drives, they must be fitted with a grooved pulley bearing on the inside of the drive, preferably on the slack side. The pulley should be positioned as close as possible to the large pulley. Flat tensioning pulleys, bearing on the outside of the drive are permissible only with ‘V’ type belts.They should be positioned within one third of the centre distance from the small pulley.

The tensioning pulley must be at least the same diameter as the small pulley of the drive.

Tensioning pulley movement can only be determined by laying out the drive to scale. It must allow for passing the belts over the outside diameter of one of the pulleys on installation, and should also allow for belt stretch.

Fuelling growth in the belts market

Anew study by Frost & Sullivan forecasts that the European belt and chain drive components market will continue to show positive growth in demand, with revenue values by 2004 expected to be some 40% higher than in 1997.

Rising interest in many end-user sectors – especially for belt drive components – is anticipated to sustain total revenue growth. Improved customer service, design enhancements and more competitive prices are also projected to generate further demand in the market.

“The need to replace or supplement obsolete equipment, or that which no longer conforms to new safety and environmental protection regulations, coupled with heightened interest across a number of end-user sectors, are expected to be major divers for growth,” says Mik Sabiers, industry manager at Frost & Sullivan.

In general, growth for chains is expected to fall as demand is affected by the rising interest in alternative drive solutions. Growth in belts is expected to be stronger.

• Fenner

April 2000