GB/T 301 covers thrust ball bearings, boundary dimensions. This page sets out what the standard fixes for 51100 series thrust ball bearings, what it deliberately leaves to other documents, its national equivalents, and the dimensional table supplied against it.
GB/T 301 — Scope
GB/T 301 is the Chinese national standard for the boundary dimensions of thrust ball bearings — the shaft washer bore, the housing washer outside diameter and the assembled height that fixes the shoulder spacing.
What GB/T 301 Does Not Fix
It fixes the envelope and not the rating, and it does not address the radial load these bearings must never be asked to carry: a thrust bearing has no radial capacity and has to be located radially by something else.
This division of labour is the thing to carry away from any bearing standard. A boundary dimension standard makes bearings interchangeable; it does not make them equivalent. Two bearings of the same designation from different makers mount in the same seat and are not required to have the same load rating, the same internal design, the same cage or the same speed limit.
Dimensions Supplied to GB/T 301
| Designation | Bore d (mm) | Outer diameter D (mm) | Height H (mm) | Chamfer r min (mm) |
|---|---|---|---|---|
| 51100 | 10 | 24 | 9 | 0.3 |
| 51101 | 12 | 26 | 9 | 0.3 |
| 51102 | 15 | 28 | 9 | 0.3 |
| 51103 | 17 | 30 | 9 | 0.3 |
| 51104 | 20 | 35 | 10 | 0.3 |
| 51105 | 25 | 42 | 11 | 0.6 |
| 51106 | 30 | 47 | 11 | 0.6 |
| 51107 | 35 | 52 | 12 | 0.6 |
| 51108 | 40 | 60 | 13 | 0.6 |
| 51109 | 45 | 65 | 14 | 0.6 |
| 51110 | 50 | 70 | 14 | 0.6 |
| 51111 | 55 | 78 | 16 | 0.6 |
| 51112 | 60 | 85 | 17 | 1 |
| 51113 | 65 | 90 | 18 | 1 |
| 51114 | 70 | 95 | 18 | 1 |
| 51115 | 75 | 100 | 19 | 1 |
| 51116 | 80 | 105 | 19 | 1 |
| 51117 | 85 | 110 | 19 | 1 |
| 51118 | 90 | 120 | 22 | 1 |
| 51120 | 100 | 135 | 25 | 1 |
National Equivalents
ISO 104 internationally; DIN 711 and DIN 715 for the single and double direction types.
This product is supplied against ISO 104 / DIN 711 / GB/T 301, which names the documents it is made to.
When to Cite GB/T 301
GB/T 301 is the Chinese national standard and is what a Chinese manufacturer works to, so citing it removes any ambiguity on an order placed in China. It restates the same dimensions as its ISO parent, so quoting both — the GB/T number and the ISO number — is the practice that survives a supply change.
