The MRP 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.
The 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 AND PHYSICAL PROPERTIES
The PolyLube® MRP bearing can withstand static loads of approximately 70,000 PSI and 30,000 PSI under dynamic loading. For dry running applications, the maximum speed is approximately 10 surface feet per minute. The typical average design pressure for high duty cycle applications is 10,000 PSI. 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 thermal expansion of the PolyLube MRP bearing is 4.8 x 10-6 in/in/°F, very close to steel and much lower than most bronze alloys.
PolyLube MRP bearings are the bearing of choice 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″ 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.
|Ultimate Compression Strength (PSI)||70,000|
|Unit Load Limit (PSI)||30,000|
|Temperature Range (°F)||± 325|
|Coefficient of Thermal Expansion (in/in/°F)||4.8 x 10-6|
|Thermal Conductivity (BTU*in(hr*ft2*°F))||1.8-2.3|
|Water Absorption (2 Hours)||0.12%|
|Water Absorption (24 Hours)||0.16%|
|Maximum Velocity (SFM)||10|