NACHI DJ 30300 series, 25 x 62 x 18.25
Available
D in the designation means a nominal contact angle over 24° and under 32°. DJ is that larger-angle design with the same ISO sub-unit dimensions (J). The DJ sizes have a constant e of 0.81 to 0.83, against 0.30 to 0.35 for the J bearings of the same numbers, and the same bearing number with J has a higher radial rating and speed limit (see Selecting the right option).
A tapered roller bearing carries combined radial and axial load. The cone (inner ring and roller assembly) and the cup (outer ring) are separable, and the internal clearance is set at mounting by the axial position of the cone relative to the cup. A single row bearing takes axial load in one direction, so for axial load both ways fit a pair, face-to-face or back-to-back.
Where this product is used
- Industrial gearboxes and speed reducers
- Wheel hubs, axles and vehicle drive trains
- Transmissions and differentials
- Conveyor drives and general industrial machinery
- Equipment with combined radial and axial loads on one shaft
Features
- Single row tapered roller bearings with a D contact angle (nominal over 24° and under 32°) and ISO sub-unit dimensions (J)
- Combined radial and axial load, a pair mounted face-to-face or back-to-back carries axial load in both directions
- Separable cone and cup: the clearance is set at mounting by the axial position of the cone against the cup, and the bearing can be preloaded for higher rigidity and running accuracy
- Constant e, axial load factors, load centre, mass and shoulder dimensions for each size in the Model Details
Key specifications
| Specification | Detail |
|---|---|
| Brand | NACHI |
| Series | 30300 |
| Bearing numbers | 14 |
| Bore d | 20 to 90mm |
| Outer diameter D | 52 to 190mm |
| Overall width T | 16.25 to 46.5mm |
| Contact angle | Nominal over 24° and under 32° (D) |
| Dimension standard | ISO sub-unit dimensions (J) |
| Basic dynamic load rating Cr | 39.8 to 282 kN |
| Basic static load rating Cor | 42.5 to 336 kN |
| Limiting speed, grease | 1,700 to 5,700rpm |
| Limiting speed, oil | 2,400 to 8,000rpm |
| Mass | 0.269 to 5.6kg |
Available sizes
| Model | Size d x D x T (mm) | Cr (kN) | Cor (kN) | Limiting speed, grease (rpm) | Limiting speed, oil (rpm) | Mass (kg) |
|---|---|---|---|---|---|---|
| 30304DJ | 20 x 52 x 16.25 | - | - | - | - | - |
| 30305DJ | 25 x 62 x 18.25 | 39.8 | 42.5 | 5,700 | 8,000 | 0.269 |
| 30306DJ | 30 x 72 x 20.75 | 50.9 | 54.9 | 4,900 | 6,800 | 0.4 |
| 30307DJ | 35 x 80 x 22.75 | 63.1 | 69.1 | 4,300 | 6,000 | 0.536 |
| 30308DJ | 40 x 90 x 25.25 | 80.5 | 90.2 | 3,800 | 5,300 | 0.757 |
| 30309DJ | 45 x 100 x 27.25 | 95.1 | 107 | 3,400 | 4,700 | 0.973 |
| 30310DJ | 50 x 110 x 29.25 | 115 | 133 | 3,100 | 4,300 | 1.25 |
| 30311DJ | 55 x 120 x 31.5 | 129 | 148 | 2,900 | 4,000 | 1.59 |
| 30312DJ | 60 x 130 x 33.5 | 153 | 179 | 2,600 | 3,700 | 2.01 |
| 30313DJ | 65 x 140 x 36 | 176 | 209 | 2,400 | 3,400 | 2.44 |
| 30314DJ | 70 x 150 x 38 | 197 | 235 | 2,300 | 3,200 | 2.97 |
| 30315DJ | 75 x 160 x 40 | 222 | 266 | 2,100 | 2,900 | 3.47 |
| 30316DJ | 80 x 170 x 42.5 | 236 | 282 | 2,000 | 2,800 | 4.12 |
| 30318DJ | 90 x 190 x 46.5 | 282 | 336 | 1,700 | 2,400 | 5.6 |
Fitting and use
A radial load on a single row tapered roller bearing creates an induced axial load, Fa' = Fr / (2 x Y1), which tries to separate the cone and cup. It is normally balanced by mounting two bearings as a pair or as a multi-row set, so work out the axial load on each bearing, not just the one that carries the thrust.
The internal clearance is set when you mount the bearing, by the axial position of the cone against the cup.
Limiting speeds are given for grease and for oil lubrication.
Choosing the right option
DJ or J? The DJ bearing has the same bore, outside diameter, cone width B and overall width T as the J bearing of the same number, but a larger contact angle and a narrower cup (for example C 17mm on the 30308DJ against 20mm on the 30308J). It a lower radial rating and a lower speed limit: the 30308DJ is Cr 80.5 kN with a 3,800rpm grease limit, against Cr 90.6 kN and 4,500rpm for the 30308J.
To work out the equivalent dynamic load Pr for a single bearing: where Fa/Fr is at or below e, Pr = Fr; above e, Pr = 0.4 x Fr + Y1 x Fa. For the DJ sizes e is 0.81 to 0.83 and Y1 is 0.73 to 0.74, and the values for each size are in the Model Details.
The load centre a is negative for these sizes (-12.6 to -2.2mm): the minus sign means the load centre lies outside the cone back face, which matters when you work out shaft and housing loads.
Check the full designation, including the DJ, when you order.
The standard-angle J bearings of the same numbers are on the: NACHI metric J tapered roller bearings page.
Inch series sizes are on the pages for the: NACHI LM48548/10, NACHI LM11949/10.
Other NACHI bearing types: NACHI single row angular contact ball bearings, NACHI spherical roller bearings, NACHI cylindrical roller bearings.
| Option | Part number | SKU |
|---|---|---|
| 20 x 52 x 16.25 | A0106224 | |
| 25 x 62 x 18.25 | A0106225 | |
| 30 x 72 x 20.75 | A0104991 | |
| 35 x 80 x 22.75 | A0104993 | |
| 40 x 90 x 25.25 | A0104995 | |
| 45 x 100 x 27.25 | A0106226 | |
| 50 x 110 x 29.25 | A0104997 | |
| 55 x 120 x 31.5 | A0106228 | |
| 60 x 130 x 33.5 | A0105000 | |
| 65 x 140 x 36 | A0105002 | |
| 70 x 150 x 38 | A0105004 | |
| 75 x 160 x 40 | A0105006 | |
| 80 x 170 x 42.5 | A0105008 | |
| 90 x 190 x 46.5 | A0106229 |
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NACHI DJ Tapered Roller Bearings, 30300 Series, 24° to 32° Contact Angle, 20 to 90 mm Bore: 25 x 62 x 18.25
SKU: A0106225 | Model: 30305DJ/NACHI
NACHI 30305DJ single row tapered roller bearing, 25 x 62 x 18.25mm, 24° to 32° contact angle, Cr 39.8 kN, Cor 42.5 kN.