Taper Roller Bearings

Alt text

The inner and outer ring raceways are segments of cones and the rollers are also made with a taper so that the conical surfaces of the raceways and the roller axes if projected, would all meet at a common point on the main axis of the bearing.

This conical geometry is used as it gives a larger contact patch, which permits greater loads to be carried than with spherical (ball) bearings, while the geometry means that the tangential speeds of the surfaces of each of the rollers are the same as their raceways along the whole length of the contact patch and no differential scrubbing occurs. When a roller slides rather than rolls, it can generate wear at the roller-to-race interface, i.e. the differences in surface speeds creates a scrubbing action. Wear will degenerate the close tolerances normally held in the bearing and can lead to other problems. Much closer to pure rolling can be achieved in a tapered roller bearing and this avoids rapid wear.

The rollers are guided by a flange on the inner ring. This stops the rollers from sliding out at high speed due to their momentum.

The larger the half angles of these cones the larger the axial force that the bearing can sustain.

Tapered roller bearings are separable and have the following components: outer ring, inner ring, and roller assembly (containing the rollers and a cage). The non-separable inner ring and roller assembly is called the cone, and the outer ring is called the cup. Internal clearance is established during mounting by the axial position of the cone relative to the cup.

Specifications

Bearings Symbol d D B C T r
(min)
r1
(min)
a Load Rating (daN) Max
Speed RPM
Dynamic (C) Static (Co)
30203 17 40 12 11 13.25 1 1 3.5 2080 1900 9800
30204 20 47 14 12 15.25 1 1 4 3100 3150 8400
30205 25 52 15 13 16.25

1

1 3.5 3600 3950 7500
30206 30 62 16 14 17.25 1 1 3.5 4600 4900 6300
30207 35 72 17 15 18.25 1.5 1.5 3 5800 6200 5300
30208 40 80 18 16 19.75 1.5 1.5 3 6000 6400 4800
30209 45 85 19 16 20.75 1.6 1.6 3 6700 7400 4300
30210 50 90 23 19 24.75 1.5 3 3.75 82500 100000 4300
30214 70 125 24 21 26.25 1.5 2 1 12000 14000 2800
30215 75 130 25 22 27.25 1.5 2 0.5 13600 16600 2700
                       
30302 15 42 13 11 14.25 1.0 1.5 4.57 2330 2070 9000
30305 25 62 17 15 18.25 1.5 1.5 5.5 4600 4300 6700
30306 30 72 19 16 20.75 1.5 1.5 4.5 5500 5200 5600
30308 40 90 23 20 25.25 1.5 2 5.45 8900 9600 4300
30312 60 130 31 26 33.5 2.5 3 7.5 15000 16000 2900
                       
31312 59.985 34.983 30.925 21.948 33.449 3.5 3.5 7 152000 172000 3200
                       
32207 35 72 23 19 24.25 1.5 1.5 6 7000 8000 5300
32208 40 80 23 19 24.75 1.5 1.5 5 7800 8800 4800
32210 50 90 23 19 24.75 1.5 1.5 4 9300 11300 4000
32211 55 100 25 21 26.75 1.5 2 3 10650 13140 3600
32212 60 110 28 24 29.75 1.5 2 5.75 12720 16030 3400
32213 65 120 31 27 32.75 0.8 3.5 5 15550 19550 3200
32214 70 125 31 27 33.25 1.5 2 5.25 15770 20760 3800
32216 80 140 33 28 35.25 2 2.5 4.5 17700 21900 2500
32217 85 150 36 30 38.5 2 2.5 3.5 21500 28500 2400
32307 35 80 31 25 32.75 1.5 2 12.5 10000 10800 5000
32308 40 90 33 27 35.25 1.5 2 11.7 11500 13300 4300
32309 45 100 36 30 38.25 1.5 2 10.5 14200 17700 3900
32312 60 130 46 37 48.5 2.5 3 16 22300 27000 2900