Understanding V-belt Construction Terms

V-belt construction features can be described by a variety of terms, which can cause confusion.  Here are some of the most common terms you may encounter:

• Banded:
• A fabric layer surrounds the belt
• Also referred to as wrapped or covered
• Bareback:
• A type of banded V-belt where the fabric is not impregnated with rubber
• Also referred to as low friction, dry cover, or clutching cover
• Bandless:
• No fabric surrounding the belt
• Also referred to as cut edge, raw edge, or machined edge
• Notched:
• The bottom of the belt is notched (not flat)
• Also referred to as cogged, molded notch, or cut notch
• PowerBand®:
• Multiple V-belt strands joined with a common backing
• Also referred to as joined

Interchanging OEM Original Equipment V-belts With Standard Aftermarket V-belts

V-belts are commonly used in many light duty type applications including outdoor power equipment (lawn mowers, rotor tillers, snow blowers, etc.), light duty ventilation fans, power tools (table saws, drill presses, wood lathes, etc.) and much more.  V-belts eventually need to be replaced, and obtaining appropriate replacements can be challenging.

OEM Originals

Replacement belts can nearly always be obtained from the original equipment manufacturers, and this is usually the best practice.  OEM Manufacturers often use belts that have been custom manufactured for them in special constructions or in custom lengths that function best in their equipment.  These special constructions are proprietary, so the special features may not be easily determined.

Truflex and PowerRated Replacements

If original OEM V-belts cannot be obtained, replacement belts can sometimes be identified dimensionally although performance and functionality may not be the same as the OEM originals.  When considering replacement belts from our Truflex and PowerRated light duty V-belt product lines, there are additional considerations.

Clutching Applications

Some applications use belts to provide a clutching function to engage and disengage the equipment.  Only PowerRated type V-belts should be used in these applications as they have been designed with a bareback type cover that allows graceful slippage and aramid tensile cords that will not shrink like Truflex V-belts when hot from slippage.  Using conventional Truflex V-belts could cause unsafe machinery engagement and belt shrinkage could prevent disengagement, resulting in potentially hazardous circumstances.

V-belt Length Variations

Standard Truflex and PowerRated V-belts may not fit applications like OEM originals.  Standard V-belts may be too short to easily install or too long, resulting in adjustment pulleys moving to the end of their travel and not able to apply sufficient belt installation tension.  The position of spring loaded tensioning pulleys may also change, resulting in an increase of decrease in the proper belt tension.

PowerRated For Increased Robustness

Identically sized PowerRated V-belts can sometimes be used in place of Truflex V-belts for added load capacity and robustness.  This can sometimes improve belt service life when Truflex V-belt performance is less than desired.  Truflex V-belts should generally not be substituted for PowerRated V-belts, though.

Interchanging with Industrial V-belts

Identically sized Industrial A-Section and B-Section V-belts can sometimes be used in place of Truflex V-belts for added load capacity and durability.  Note, however, that small sheave diameters often used in these applications may be too small for solid banded A-Section and B-Section V-belts.  AX-Section and BX-Section (notched) V-belts are more flexible and tolerant of small sheave diameters, so may perform better.

Summary
Identifying correct replacement belts for equipment can be challenging.  We recommend that you consult original equipment manufacturers first for the best replacement.  Then consider the functionality needed by the belt in selecting V-belts from our standard product lines.  Contact Gates Product Application Engineering for further information at 303.744.5800 or ptpasupport@gates.com.

Will It Fit - GT2 Sprockets

What belt will fit into what industry standard sprocket is a question we regularly receive here in Product Application Engineering.  Below is information regarding what Gates belts will fit into standard PowerGrip GT2 sprockets.  

For any additional questions feel free to look through our other blog topics or contact us at ptpasupport@gates.com or 303-744-5800.

Minimizing V-belt Drive Noise

To minimize the noise level of your V-belt drive, pay close attention to tension and alignment.

Improper V-belt tension can cause the belt to slip and squeal. Misalignment creates interference at the belt’s entry point into the sheave, resulting in a louder drive.

Information on proper belt installation tension and alignment is detailed in the V-belt manual:

HEAVY-DUTY V-BELT DRIVE DESIGN MANUAL

Hose Cleanliness

Hose Cleanliness

When the customer becomes more dependent on ISO standards, your

strategy needs to reflect a dedication to system cleanliness.

What is Hydraulic System Cleanliness?

 

“Cleanliness” is a term used to describe the level of solid and
liquid contamination found in hydraulic systems. “Contamination”

is defined as any substance that is not part of the hydraulic system’s

working fluid.

Why is cleanliness important to your customers?

There are several reasons:

 

   Efficient production - clean systems provide for maximum productivity.

   Improved control  -  spare parts use can be controlled through preventive maintenance and monitoring  contamination.

   Reduce equipment downtime  - through scheduled inspections

   Safety hazards minimized - through preventing contamination related

failure for increased life expectancy of components on equipment.

Reduced repair cost  - due to fewer breakdowns.

 

Several reputable sources have claimed that 70 to 80 percent of

hydraulic system failures are due to contamination. By establishing

a contamination control program, costly repairs and downtime may

be minimized. A contamination  control program can be as simple

as establishing an allowable level of contamination within a hydraulic

system, supplying cleaned components for the system, and monitoring

levels of contamination as part of a preventive maintenance

program.

 

 

Metric V-belt Lengths

Depending on the belt type and the manufacturer, metric V-Belt part number may specify different length measurements. The different belt lengths, abbreviations, and their relative positions in the belt are:



Gates classical Metric Power™ V-belts (e.g 10X, 13X, 17X) specify inside length in millimeters followed by”Li”. Narrow Gates Metric Power V-belts (e.g. SPZ, SPA, SPB, SPC) specify the datum/pitch length in millimeters.

Converting one length type into another may be required to identify if a proper replacement belt exists. The following table converts between any of the four length measurements. To find the correct equation, read the column headings across the top and choose the appropriate belt cross section. Read down the rows at the left and select the belt length type to calculate. Reading down the selected column and across the selected row, the box at the intersection lists the equations to convert from any of the other three length types.

Using Extra Wide Driven Sprockets and Sheaves to Increase Bore Ranges

Hardware component selections for normal belt drives use the same widths for both the driver and driven sprockets or sheaves.   This looks normal and works well most of the time.

But what if the driven shaft diameter is unusually large and exceeds the bore range of the selected driven sprocket or sheave?  One option is to re-design and select hardware components with larger bore ranges.  Another option is to consider using a driven component in the same diameter, but in a wider width than necessary.

For example, an 8MX-140S-12 sprocket uses a 2012 bushing with a maximum bore of 2.125”.  An 8MX-140S-21 sprocket uses a 2517 bushing with a maximum bore of 2.688”.  In this case, just using a sprocket with a 21mm face width instead of a 12mm face width will increase the sprocket bore range from 2.125” to 2.688”, which is considerable.  This principle can apply to other sprocket, pulley and sheave types as well.

With synchronous belt drives there is no harm in using wider driven sprockets so long as the driver sprocket is double flanged so the belt is constrained appropriately on both sides.  A wider driven sprocket may look unusual, but will function just fine.  And the parallel sprocket alignment isn’t as critical with the wider sprocket face width.

With V-belt drives there is no harm in using wider driven sheaves.  There may be some empty sheave grooves in the wider driven sheave, but this will not pose any problems.  Just be sure to accurately align the driver sheave grooves with the driven sheave grooves that will contain V-belts.

For questions or further information, contact Gates Product Application Engineering at 303-744-5800 or at ptpasupport@gates.com