What is ODR?

ODR stands for Over-Design Ratio. In Design Flex you specify an input load and service factor which determines a Design Power by multiplying those values together. Design Flex then searches for drives that meet or exceed that design power. The over-design ratio is the belt’s Rated Load divided by that design power. If the ODR equals 1.00 then you have found a belt drive that is rated at your design power. If the ODR is less than 1 then the drive may be under-designed for the application. If it's over 1 then the drive is suitable for the application. Be careful though. If a drive is too over-designed it will reduce efficiency and can potentially damage other drive components.

NAHBS 2015 and Shimano STEPS

NAHBS (North American Handmade Bicycle Show) was held last weekend in Louisville, KY.  The show was excellent as usual, with the additional of a very interesting new E-bike motor from Shimano.  The show included several bikes with the new STEPS E-bike motor made by Shimano, also featuring their internally geared hubs, and of course a Gates Carbon Drive belt drive.

Kentucky in special to Gates, as our Poly Chain plant (the belt used in Gates Carbon Drive) is located in Elizabethtown, just a little south of Louisville.

Check out the Carbon Drive Blog for photos of some amazing bikes from the show: http://blog.gatescarbondrive.com/ 

What Are Cogs Anyway?

When communicating with end users of our belt products that are looking for replacement belts, the term “cog” is often used in describing belt features.  Because the term “cog” can be used to refer to many different shapes and features, we do not generally find it to be helpful in identifying appropriate replacements.  Incorrect belt identifications can be easily made unless industry standard and correct terminology is used.  Here are some suggested industry standard terminology to aid in describing belt features:

Longitudinal – Refers to features that lead around belt circumference, or along belt length.

Transverse – Refers to features that lead across belt width, or are perpendicular to belt circumference.  Synchronous belt teeth have a transverse direction.

Notch – V-belts and multi-speed belts are sometimes notched to improve bending flexibility.  Notches can be confused with teeth but the type of hardware used with the belts helps to distinguish.  Notched V-belts run in grooved sheaves and synchronous belt teeth operate in pulleys or sprockets with transverse grooves.

Notched V-Belt

Notched Multi-Speed Belt

Rib – Belt ribs are generally longitudinal in nature, as with Micro-V belts or with multiple strand PowerBand type V-Belts.  Poly Chain and Polyflex type belts have small transverse ribs on their backs.

Longitudinal Ribbed Micro-V Belt

Back Ribs On Poly Chain Belts

Grooves – May be longitudinal if referring to V-belt sheaves, or transverse if referring to synchronous pulleys or sprockets.

Sheave Grooves - Longitudinal

Sprocket Grooves - Transverse

Teeth – Generally refer to transverse features, such as teeth on synchronous belts. Synchronous belt teeth may be described as trapezoidal, curvilinear or gear shaped depending on the belt type.

Trapezoidal Timing Belt Teeth

Curvilinear Synchronous Belt Teeth

These useful belt related terms can be used instead of “cog” when describing belt features.  Feel free to contact us at ptpasupport@gates.com or on our HelpLine at 303-744-5800.

Identifying Issues in Hydraulic Systems: Hose Cracks

Problem:

Hose cover or tube has cracks and appears hardened.

This is typically caused by exposure to excessive heat and/or ozone.  Excessive heat can be created by:

• Routing near a heat source such as an exhaust manifold.
• Using an undersized hose or reservoir.

An increase of 18 degrees F above the maximum temperature may decrease hose life by half.  Cracks can also be caused by flexing, expecially at excessively low temperatures.  Never exceed the temperature rating of the hose.

Solution:  

Select a hose that meets the temperature and flow requirements of the application.  Also, identify the heat source and consider re-routing the hose away from the source to minimize the heat's effects.  Examine reservoir size if necessary.

Safe Hose Selection: Delivery

An effective way to remember hose selection criteria is to

remember the word STAMPED.

S T A M P E D

S = Size

T = Temperature

A = Application

M = Material to be Conveyed

P = Pressure

E = Ends or couplings

D = Delivery (volume)

D

Delivery – (Volume and Velocity)

Determined the hose I.D. needed to transport required fluid a volume by using a Nomographic Chart for finding the correct Hose Inside Diameter with known Flow Rate and Fluid Velocity in the Gates Hydraulic Catalog or Pressure Drop program found on the Gates Web site. 

How much fluid must go through the hose? This will determine the size of hose that must be used. Under-sizing a hose leads to increased pressure loss. Over-sizing the hose adds unnecessary cost, weight and bulk.