PRELOADED BEARINGS FOR ROTARY MOTION ONLY
The MR Series ball bearings are designed and manufactured for those applications where purely radial loads must be supported in a PRELOADED condition. They are ideally adapted to those applications where the necessary clearance in needle and roller bearings is not desirable. “MR” type bearings are fitted with nitrile rubber wiper seals. The retainer is held between two flat retaining rings which also back up the seals.
Type MR Engineering Data
Series “MR” bearings supporting pure radial loads must be used with an interference fit between the balls and the shaft. In such applications, the shaft must be made to the dimensions and tolerances given below. The outer races and balls are of 535 A99 steel. Shafts should be hardened to at least 60 HRC and ground to at least 0.25nm.
Metric Range
DIMENSIONS AND SPECIFICATIONS
| Bearing Ref | B Shaft Dia | D Bearing O.D. | L+.00 -.13 |
| MR 16-28 | 16 | 28 | 29.00 |
| MR 20-32 | 20 | 32 | 34.00 |
| MR 25-39 | 25 | 39 | 38.00 |
| MR 32-46 | 32 | 46 | 49.00 |
| MR 40-55 | 40 | 55 | 57.00 |
| MR 50-70 | 50 | 70 | 72.00 |
SHAFT AND HOUSING TOLERANCES AND RESULTING FITS
| Bearing Ref | Seal O.D. A | Housing Dh* | Shaft Bs | Pre Load Interference Fit ‡ | Eccentricity O.D. to Bore | Maximum R.P.M. | Basic Capacity KN | Static Capacity KN | |||
| Min | Max | ||||||||||
| MR 16-28 | 25.40 | 28.00 | +.007 -.005 | 16.00 | +.000 -.005 | .002 | .012 | .007 | 13,000 | 1.50 | 1.34 |
| MR 20-32 | 29.36 | 32.00 | +.010 -.005 | 20.00 | +.000 -.005 | .002 | .012 | .010 | 12,000 | 1.94 | 1.91 |
| MR 25-39 | 36.50 | 39.00 | +.013 -.005 | 25.00 | +.000 -.005 | .002 | .012 | .010 | 10,000 | 2.45 | 2.24 |
| MR 32-46 | 42.85 | 46.00 | +.013 -.005 | 32.00 | +.000 -.005 | .002 | .012 | .010 | 8,000 | 3.63 | 4.18 |
| MR 40-55 | 51.81 | 55.00 | +.013 -.005 | 40.00 | +.000 -.005 | .002 | .012 | .010 | 7,000 | 4.41 | 5.37 |
| MR 50-70 | 63.50 | 70.00 | +.013 -.005 | 50.00 | +.000 -.005 | .002 | .012 | .010 | 5,000 | 6.91 | 9.34 |
Inch Range
DIMENSIONS AND SPECIFICATIONS
| Bearing Ref | B Shaft Dia | D Bearing O.D. | L+.000 -.005 |
| MR 500-875 | .5000 | .8750 | .937 |
| MR 625-1000 | .6250 | 1.0000 | 1.125 |
| MR 750-1250 | .7500 | 1.2500 | 1.312 |
| MR 875-1500 | .8750 | 1.5000 | 1.500 |
| MR 1000-1625 | 1.0000 | 1.6250 | 1.750 |
| MR 1125-1750 | 1.1250 | 1.7500 | 2.000 |
| MR 1250-1875 | 1.2500 | 1.8750 | 2.250 |
| MR 1500-2125 | 1.5000 | 2.1250 | 2.500 |
| MR 1750-2625 | 1.7500 | 2.6250 | 2.875 |
| MR 2000-2875 | 2.0000 | 2.8750 | 3.187 |
SHAFT AND HOUSING TOLERANCES AND RESULTING FITS
| Bearing Ref | Seal O.D. A | Housing Dh* | Shaft Bs | Preload Interference Fit ‡ | Eccentricity O.D to Bore | Maximum RPM | Basic Capacity Lbf | Static Capacity lbf | |||
| Min | Max | ||||||||||
| MR 500-875 | .875 | .8750 | +.0003 -.0002 | .5000 | +.0000 -.0002 | .0001 | .0005 | .0003 | 14,000 | 230 | 158 |
| MR 625-1000 | 1.000 | 1.0000 | +.0003 -.0002 | .6250 | +.0000 -.0002 | .0001 | .0005 | .0003 | 13,000 | 352 | 302 |
| MR 750-1250 | 1.125 | 1.2500 | +.0004 -.0002 | .7500 | +.0000 -.0002 | .0001 | .0005 | .0004 | 12,000 | 440 | 430 |
| MR 875-1500 | 1.312 | 1.5000 | +.0004 -.0002 | .8750 | +.0000 -.0002 | .0001 | .0005 | .0004 | 11,000 | 562 | 503 |
| MR 1000-1625 | 1.437 | 1.6250 | +.0004 -.0002 | 1.0000 | +.0000 -.0002 | .0001 | .0005 | .0004 | 10,000 | 688 | 692 |
| MR 1125-1750 | 1.562 | 1.7500 | +.0004 -.0002 | 1.1250 | +.0000 -.0002 | .0001 | .0005 | .0004 | 9,000 | 814 | 907 |
| MR 1250-1875 | 1.687 | 1.8750 | +.0005 -.0002 | 1.2500 | +.0000 -.0002 | .0001 | .0005 | .0004 | 8,000 | 967 | 1195 |
| MR 1500-2125 | 1.937 | 2.1250 | +.0005 -.0002 | 1.5000 | +.0000 -.0002 | .0001 | .0005 | .0004 | 7,000 | 1147 | 1612 |
| MR 1750-2625 | 2.312 | 2.6250 | +.0005 -.0002 | 1.7500 | +.0000 -.0002 | .0001 | .0005 | .0004 | 6,000 | 2185 | 2978 |
| MR 2000-2875 | 2.562 | 2.8750 | +.0005 -.0002 | 2.0000 | +.0000 -.0002 | .0001 | .0005 | .0004 | 5,000 | 2490 | 3733 |
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Bearing reference indicates bearing type, shaft diameter and outside diameter. |
‡ Between Shaft, Balls and Outer Sleeve I.D. |
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Larger, heavy duty and special types are available. Please contact us to discuss your requirements |
*CAUTION: Excessive press fits may affect preload. If in doubt please contact us for alternative mounting methods. |
Lubrication and Temperature Requirements
All bearings are supplied in rust preventative oil and should be cleaned and lubricated before use. Good quality medium oils and light ball bearing greases have the advantage of greater surface cohesion. High grade light oil will allow a higher operating speed and greater sensitivity to movement. Working temperatures under maximum load conditions should not exceed 120°C although the bearings can operate safely at slightly higher temperatures and under decreased load conditions, with special lubricants. For continuous high temperature operation, suitable grades of silicone grease should be used.