Features and Benefits: Belt Design and Wear

n  Belt is designed to transfer torque to the limits of the machine, then slip or break if the limit is exceeded— ·        Ensures that the machine will operate properly and provides protection to machine components n  Belt failure rate is monitored in the field — ·        Ensures that quality is maintained and allows changing belt type and design if necessary.

ILLUS. NO. MPO915

The function of a drive belt is to transfer rotation (torque) from the powered pulley to one or more driven pulleys.  The belt must be designed and manufactured to transfer this torque efficiently and reliably.  It should also be designed to slip or break if upper torque limits are exceeded in order to prevent possible damage to other components.

Additional Design Considerations

During the development of a new John Deere machine, engineers test various belt designs to ensure that the one selected has the specified requirements.

Illus. No. MPO914

The illustration shows the important areas of a typical V-belt cross-section.  Each area plays an important role in how the belt will perform for the function and application.  The top section of the belt is the tension section.  It is rubber and stretches as the belt forms around the sheave. The bottom section is called the compression section because it compresses when wedged into and shaped around the sheave.

The center section of the belt is the strength section.  It neither compresses nor stretches, but the cords located in this area give the belt its tensile strength.  Without these cords, a V-belt would be pulled apart.

The complete belt is covered by a cover section of tough fabric and rubber which protects the inner parts.

In addition to being able to transfer torque efficiently then slip or break to protect machine components, the factors listed below are taken into consideration when designing and selecting a drive belt:

·        Additional idlers and multiple sheaves and pulleys cause unique wear characteristics as well as altering stress points.

·        Unusual heat generated by pressure and stress forces when a belt is operating will further cure a belt to the point that it fails prematurely.

·        Lateral stress is an engineering consideration.

·        Sidewall material is selected with regard to friction coefficients, wear factors, and weather resistance.

Many belts are tested in a given application and environment before selecting the best belt for a new machine.

Belt Failure Rate Monitored

Belt failure rate is monitored in the field to determine if performance is satisfactory or if a change in type or design is required.

Same Quality as Original Equipment

To ensure that the machine continues to perform properly, it is important that replacement belts have the same high quality and design as the original equipment belts.  With John Deere replacement belts, this is assured.