HK5025 Drawn Cup Needle Roller Bearing
HK5025 is a drawn cup needle roller bearing, open ends series, with a 50 mm needle complement diameter, a 58 mm outside diameter and a 25 mm width. Those three numbers are ISO 3245 standard values, identical for every manufacturer.
Dimensions
All HK Series designations- Designation
- HK5025
- Type
- Drawn cup needle roller bearing — radial
- Series
- HK Series (open ends)
- Size digits
- 5025 — Fw 50 mm and C 25 mm
- needle complement diameter Fw
- 50 mm (1.9685 in)
- outside diameter D
- 58 mm
- width C
- 25 mm — the assembled width
- Radial section
- 4 mm = (D − Fw) / 2
Nominal values in millimetres as published in ISO 3245, the boundary dimension plan this type is tabulated in. This type is not tabulated with a chamfer here: ISO 3245 does tabulate a chamfer minimum r alongside the boundary dimensions, but the catalogue tables consulted for this type print Fw, D and C only, so no second source exists for the cell — so no chamfer figure meets this library’s rule of a checkable second source, and none is printed. That is an absence, not a zero. 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 designationtwo fields, and neither of them a bore
This one is not assembled the way the rest of this library assembles a designation — HK5025 is written HK followed by two boundary dimensions, and there is no bore code and no dimension series in it. The first pair of digits is Fw, the diameter of the needle complement and so the shaft this one has to be ground to; the second pair is C, the width of the cup. Both are already in millimetres and neither is multiplied by five. The outside diameter is in neither of them — HK5025 is 58 mm across, and that figure comes from the ISO 3245 boundary table for its diameter series, never from the part number.
Position in the series61 of 62 in HK Series
No radial clearance table on this pagedrawn cup needle roller bearing
ISO 5753-1 does not cover this type at all: it leaves drawn cup needle roller bearings out of its scope in as many words, so the absence here is the standard’s own and not this library’s — there is no drawn cup table in it to reproduce. That is a third case, and it is not either of the two above: a tapered roller bearing is given a different quantity and a thrust ball bearing has no radial clearance to state, while a drawn cup needle roller bearing is simply outside the document’s scope.
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, ISO 3245) 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.