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Our most popular composite bearing

Polygon MRP 900x600The MRP is a highly versatile composite bearing for applications that require high load capacity, low frictional values, along with minimal wear characteristics.

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Product History

The MRP composite bearing was born from Polygon’s continuous improvement efforts. Original targets for the bearing were lower cost and lower performance. The actual result was a decrease in cost due to thorough analysis and value stream mapping of the manufacturing process and virtually identical performance compared to our legacy product. The MRP bearing has become the standard product offered for bearing customers and has supplanted the legacy product.

Product Description

MRP Composite Bearing LinerThe MRP has a unique added lubricant embedded within the surface of the liner material to decrease the initial coefficient of friction. This small change was initiated because in certain lightly loaded joints, upon initial actuation, an intermittent stick-slip or noise could be generated. The MRP addresses this issue by decreasing friction and virtually eliminating the typical break in period.

PolyLube MRP bearings are designed to minimize wear; however, the bearing wear is affected by the general operating conditions, such as speed, sliding distance and load. With intermittent rotation or oscillation, radial wear should be negligible over thousands of hours. Hard chrome plating gives excellent wear performance and protects the shaft from corrosion. Softer coatings such as cadmium or zinc may exhibit different wear characteristics but are perfectly suitable for use against the MRP surface.

Mechanical & Physical Properties

Specification Imperial Metric
Ultimate Compression Strength  70,000 PSI 483 MPa
Unit Load Limit 30,000 PSI 207 MPa
Temperature Range (Standard Formulation)* ±325°F -198 to 163°C
Coefficient of Thermal Expansion 4.8 x 10-6 in/in/°F 8.69 x 10-6 m/m/°C
Thermal Conductivity 1.8-2.3 (BTU*in(hr*ft2*°F)) .26 - .33 W/m*°K
Water Absorption (2 hours) 0.12%  
Water Absorption (24 hours) 0.16%  
Specific Gravity 1.87  
Maximum Velocity 10 SFM .05 m/s

* special resin formulation available up to 475°F (245°C)

The PolyLube MRP bearing can withstand static loads of approximately 70,000 PSI and 30,000 PSI (483 MPa and 207 MPa) under dynamic loading. For dry running applications, the maximum speed is approximately 10 surface feet per minute (0.05 m/s). The typical average design pressure for high duty cycle applications is 10,000 PSI (69 MPa).

This bearing’s operating temperature range is ±325°F (-198 to 163°C). Maximum continuous operational surface temperature for the standard formulation is 325°F (163°C), 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 bearing is approximately 4.8 x 10-6 in/in/°F (8.69 x 10-6 m/m/°C), lower than steel and most metals.

mrp cof graph

Applications

MRP composite bearings excel in highly loaded bearing joints where a life cycle of over 500,000 cycles is desired. Testing has shown this bearing has wear under 0.006" (0.15mm) after 1.6 million cycles. Applications include material handling equipment, high duty cranes, earth-moving equipment, construction equipment, agriculture equipment and food processing systems. MRP bearings have extremely low absorption rates and are well designed for wet and submerged applications.

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Disclaimer

Any ratings are typical for design purposes. Your design parameters may affect final ratings. Consult with a Polygon sales engineer for guidance. 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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