Determining Allowable Belt Working Tension Values

We often receive requests for allowable belt working tensions for synchronous belts from users designing linear type belt drive systems that pull carriages or masses back and forth.  These types of applications are very different than traditional power transmission systems operating at high speeds, but yet all belt drive systems share the same basic principles of power transmission physics.

Belt Working Tensions vs. Power Ratings

Synchronous belt drive systems function by transmitting a “pull” exerted by driver pulleys/sprockets into belts.  This belt “pull” may be applied to driven pulleys/sprockets, or may be applied directly to carriages or masses in linear reciprocating type systems.  All synchronous belts have rated “pull” values assigned based on pulley/sprocket diameters and operating speed.  The vast majority of belt drive applications are sized based on horsepower or torque loads, so rated belt working tension values are presented as rated power in table form for ease of use.

Calculating Belt Working Tension Values

One can easily obtain belt working tension values by starting with drive horsepower ratings.  Follow these three steps to determine belt working tension values:

1)  Determine the drive horsepower rating based on pulley/sprocket size and operating speed from published power rating tables or Gates drive design software.

2)  Convert horsepower to torque with the following equation:  Torque (lb-in) = (HP x 63025) / rpm.

3)  Convert torque (lb-in) to belt working tension by dividing the torque in step 2 by pulley/sprocket radius (in).  Radius can be calculated by dividing pulley/sprocket pitch diameter (in) by 2.

Belt working tension values should be applied with appropriate drive service factors, like drive power ratings.  Multiply target pull loads for linear applications by appropriate service factors to obtain “design pull values”.  Then make sure belt working tension values are greater than or equal to “design pull values”.  Increasing belt widths and sprocket diameters both increase belt working tension values.

Summary

Belt working tension values are ultimately based on belt fatigue characteristics, and built into belt power ratings for all types of synchronous belts.  Use the three simple steps above to convert drive power ratings to belt working tensions for easy use in linear belt drive system designs. 

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

Taper LockTorque Specs

Taper Lock bushings, are a common bushing used for synchronous sprockets.  These bushings use standard fasteners that should be torqued to a specified value.  Not using a torque wrench to verify installation torque could create a safety issue.  Use the below chart to find the proper torque value that should be used for installation of your QD bushing:

Hose Construction

A hose is generally made up of three components:

1. Tube: The tube’s function is to contain the material conveyed. To investigate chemical compatibility, please refer to the chemical resistance charts and characteristics of hose stock types in Gates hydraulic catalog to identify material for a specific fluid.

2. Reinforcement: The reinforcement of a hose is the hose’s muscle. The hoses reinforcement will provide the necessary strength to resist internal pressure (suction/vacuum) or external pressure.

3. Cover: The cover protects the reinforcement and tube from environmental conditions

Why Use Hose?

There are two commons types of fluid connection — rigid tubing and hose assemblies. Rigid tubing offers the following advantages:

• Better heat dissipation.
• Tighter bend radius.
• Lighter weight.
• Ability to handle pressures exceeding 6,000 psi.

Hose assemblies, however, have the following advantages:

• Less susceptible to damage from vibration or movement.
• No brazing or specialized bending required.
• Easier to obtain in the aftermarket.
• Easier to route around obstacles.
• Sound absorption.
• Dampens pressure surges.

Today’s hydraulic hose is much lighter and provides improved bend radius compared to earlier products. With the introduction of these hoses (such as Gates MegaSys® products), the weight advantage of bent tubing has been minimized, while the bend advantage has been reduced by half. Given the availability and routing advantages of hose, maintenance personnel often prefer it over metal tubing. It is not uncommon to replace a hard-to-reach failed bent tube with a hose assembly

Cover Blisters

Hose Twist

Useful Gates.com Links

Do you ever have moments when you need to navigate to a specific webpage quickly but cant seem to find the link in a timely manner?  If this has happened to you, then below are a few helpful links to some popular industrial belting pages available on the Gates website.  

For the industrial distributor locator page please click HERE.

For 2D dimensional sheets and 3D models please visit our PartView page HERE.

For a list of downloadable catalogs please click HERE.

For the Gates Product Application Engineering YouTube page click HERE.

To download our free 2-point drive design software (DesignFlex Pro) click HERE.

To download our free multi-point drive design software (DesignIQ) click HERE.

For a list of our available mobile apps please click HERE.

To visit our Product Application Engineering page with useful links and manuals click HERE.

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

Quick Disconnect (QD) Torque Specs

Quick Disconnect, or QD bushings, are a common bushing used for V-belt sheaves.  QD bushings use standard fasteners that should be torqued to a specified value.  Not using a torque wrench to verify installation torque could create a safety issue.  Use the below chart to find the proper torque value that should be used for installation of your QD bushing: