RNA4856 Single-row Needle Roller Bearing Without Inner Ring, With Machined Rings
RNA4856 is a single-row needle roller bearing without inner ring, with machined rings, extra-light series, with a 305 mm needle complement diameter, a 350 mm outside diameter and a 69 mm width. Those numbers — the needle complement diameter, outside diameter, width and the 2 mm minimum chamfer — are ISO 1206 standard values, identical for every manufacturer.
Dimensions
All RNA 48 Series designations- Designation
- RNA4856
- Type
- Single-row needle roller bearing without inner ring, with machined rings — radial
- Bore code
- 56 — the complete bearing’s bore code
- needle complement diameter Fw
- 305 mm (12.0079 in)
- outside diameter D
- 350 mm
- width C
- 69 mm — the assembled width
- Chamfer, r s min
- 2 mm — minimum, not nominal
- Radial section
- 22.5 mm = (D − Fw) / 2
Nominal values in millimetres as published in ISO 1206, the boundary dimension plan this type is tabulated in. The chamfer figure is the minimum single chamfer dimension the plan gives (r s min); the matching maximum is in ISO 582 — which is why the row says “min” and not an equality. A bearing that has been fitted with shields or seals carries the same dimensions, because none of the suffixes touches the boundary dimension plan.
Reading the designationand why the code does not name the shaft
The designation is three fields: type, the series and the bore code. For codes 04 and above the bore is the code multiplied by five. That makes 56 read as 280 mm — but that is the complete bearing’s bore, and this one has none: it runs directly on a hardened and ground 305 mm shaft, and the code does not name that diameter. The four exceptions are 00, 01, 02 and 03 at 10, 12, 15 and 17 mm, and they belong to the complete bearing in the same way.
Position in the series14 of 15 in RNA 48 Series
No radial clearance table on this pagesingle-row needle roller bearing without inner ring, with machined rings
ISO 5753-1 does give needle roller bearings a radial clearance table of their own, and the rows for these designations are the rows of the complete bearings they share a boundary table with. Two things stop a table appearing here. The first is the same one the complete NA pages give: the catalogue versions consulted contradict each other in every clearance group, so none can be confirmed as the standard’s own. The second is particular to this type — the table is indexed by bore, and this bearing has none. Its pages state the needle complement diameter and the shaft instead, which is why the row it would need is the row of the complete bearing of the same size and not a row of its own.
What is deliberately not publishedwhy there is no load rating here
No load rating, no limiting speed and no mass appears on this page. Those are catalogue values rather than standard values: ISO 281 defines how a dynamic rating is calculated, not what it comes out as, and the result depends on internal geometry — ball or roller diameter, the complement, raceway conformity — that none of the boundary dimension plans (ISO 15, ISO 355, ISO 104, ISO 1206) fixes. Published catalogue figures for one and the same designation differ between makes by several percent at these sizes, and limiting speed additionally depends on lubrication and on whether the bearing is open, shielded or sealed. Publishing any single figure here would dress a catalogue entry up as a property of the designation. Take the rating from the catalogue of the bearing you actually buy.
The dimensions above are a different matter, and they are the reason a designation is worth anything: the boundary dimensions — bore, outside diameter and the section dimensions of the plan this type is tabulated in, plus the chamfer minimum where that plan gives one — are fixed by the standard, so every maker's bearing of this designation fits the same shaft and the same housing.