MRP Composite Bearings
A robust bearing for agricultural and construction equipment
A composite bearing for applications that require high load capacity, low frictional values, along with minimal wear characteristics.
Product History
Polygon’s MRP are our most versatile bearings. Through analysis and value stream mapping Polygon has produced an industry leader in performance and cost.
What causes bearing squeak?
MRP bearings have proved to be squeak-less after extensive testing.
Bearing squeak is more than just an annoyance, it is also an indicator of a slip-stick condition with increased friction and higher wear rates. Slip-stick conditions create vibration. If the vibration frequency is harmonic with the shaft/bearing/housing system, then squeaking will result if it is at an audible frequency. Lightly loaded joints are especially prone to these conditions.
Low friction liner
MRP bearings use highly available PTFE and other solid lubricants in the wear layer. This eliminates or dramatically reduces squeak by reducing friction and the resulting vibration. This also shortens the typical break-in period where squeaking is more likely to occur.
Testing also showed excellent wear characteristics in all conditions. MRP is recommended for applications that require high load capacity, lowered frictional values, and more.
Mechanical & Physical Properties
| Ultimate Compression Strength PSI | 70,000 |
|---|---|
| Unit Load Limit PSI | 30,000 |
| Temperature Range (Standard Formulation)* | ±325°F |
| Coefficient of Thermal Expansion in/in/°F | 7 x 10-6 |
| Thermal Conductivity BTU * in/(hr * ft2 * °F) | 1.8-2.3 |
| Water Absorption as % weight produced (2 hours) | 0.12 |
| Water Absorption as % weight produced (24 hours) | 0.16 |
| Specific Gravity | 1.87 |
| Maximum Velocity | 10 SFM |
* special resin formulation available up to 500°F
Need parts?
Download a Design guide with parts list or Compare parts online.Mechanical and Physical Properties
The PolyLube MRP bearings can withstand static loads of approximately 70,000 PSI and 30,000 PSI** under dynamic loading. At these loading levels, minimum distortion will occur. For dry running applications, the maximum speed is approximately 10 surface feet per minute.
Loading Guidelines
**Polygon's proprietary process of fiberglass filament winding results in exceptionally strong structures to support the PolyLube wear surface. Loading in excess of 30,000 PSI can be tolerated in specific applications. A more general design approach for applications with oscillating pins and angular force vector change less than 45 degrees should be designed to an average working pressure of 8,000 psi. Polygon MRP and Fiber bearings will allow pressure spikes as high as 12,000 PSI during approximately 5% of the operational life.
Applications running with a stationary pin and a a fully rotational bearing should be designed to an average working pressure of 6,000 psi. In these applications, Polygon's MRP and Fiber bearings will allow pressure spikes as high as 10,000 PSI during approximately 5% of operational life.
Please consult with a Polygon Application Engineer for any questions regarding loading conditions and bearing performance.
Temperature
This bearing’s operating temperature range is ±325°F. Maximum continuous operational surface temperature for the standard formulation is 325°F, depending upon load characteristics. The bearing has been heat stabilized at these temperatures, so that little dimensional change will occur in the bearing during operation. In a free state, the coefficient of expansion of the PolyLube MRP bearings are approximately 7 x 10-6 in/in/°F, similar to the coefficient of expansion for steel, and actually less than some metals.
Applications
PolyLube MRP bearings are the bearing of choice in highly loaded bearing joints with a life of over 500,000 cycles. Testing has shown this bearing has wear under 0.006" after 1.6 million cycles. Applications include material handling equipment, high duty cranes, earth-moving equipment, construction equipment, agriculture equipment and food processing systems.
Disclaimer
Any ratings are typical for design purposes. Final testing and approval is the customer's responsibility for their application. This information is derived from our testing and published data. There is no assurance of these properties, or warranty provided that these products are suitable for any particular purpose or operational situation.
Polygon certifies that their product will be free from material defect. Polygon will not accept any liability for loss, damages, or costs from use or misuse of our products.
Specifications are subject to change, and may be affected by our continual process of improvement. Changes may be made without prior announcement.
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