The dimensional and running accuracy of rolling bearings has been standardized internationally (Bearing tolerance). The tolerance symbols and their definitions are provided in table as blow:
|
Tolerance symbol |
Definition |
| Radial bearings inner ring - cylindrical and tapered bore | |
| d |
|
| Δdmp |
|
| Δds | Deviation of a two-point size of bore diameter of a cylindrical bore from its nominal size |
| Vdsp | Range of two-point sizes of bore diameter in any cross section of a cylindrical or tapered bore |
| Vdmp | Range of mid-range sizes (out of two-point sizes) of bore diameter obtained from any cross section of a cylindrical bore |
| B | Nominal inner ring width |
|
ΔBs Normal, Modified1) |
|
| VBs |
|
| Kia | Circular radial run-out of inner ring bore surface of assembled bearing with respect to datum, i.e. axis, established from the outer ring outside surface |
| Sd | Circular axial run-out of inner ring face with respect to datum, i.e. axis, established from the inner ring bore surface |
| Sia | Circular axial run-out of inner ring face of assembled bearing with respect to datum, i.e. axis, established from the outer ring outside surface |
| Radial bearings inner ring - tapered bore only | |
| d1 | Nominal bore diameter at the theoretical large end of a tapered bore |
| Δd1mp | Deviation of a mid-range size (out of two-point sizes) of bore diameter at the theoretical large end from its nominal size |
| SL | Taper slope, the difference between nominal diameters at the theoretical large end and small end of a tapered bore (d1 - d) |
| ΔSL | Deviation of taper slope of a tapered inner ring bore from its nominal size |
| Radial bearings outer ring | |
| D | Nominal outside diameter |
| ΔDmp | Deviation of a mid-range size (out of two-point sizes) of outside diameter in any cross section from its nominal size |
| ΔDs | Deviation of a two-point size of outside diameter from its nominal size |
| VDsp | Range of two-point sizes of outside diameter in any cross section |
| VDmp | Range of mid-range sizes (out of two-point sizes) of outside diameter obtained from any cross section |
| C | Nominal outer ring width |
|
ΔCs Normal, Modified1) |
|
| VCs |
|
| Kea | Circular radial run-out of outer ring outside surface of assembled bearing with respect to datum, i.e. axis, established from the inner ring bore surface |
| SD | Perpendicularity of outer ring outside surface axis with respect to datum established from the outer ring face |
| Sea | Circular axial run-out of outer ring face of assembled bearing with respect to datum, i.e. axis, established from the inner ring bore surface |
| Chamfer limits | |
| rs | Single chamfer dimension |
| rs min | Smallest single chamfer dimension of rs, r1, r2, r3, r4 … |
| r1, r3 | Radial direction chamfer dimensions |
| r2, r4 | Axial direction chamfer dimensions |
| Tapered roller bearings | |
| T | Nominal assembled bearing width |
| ΔTs | Deviation of minimum circumscribed size of assembled bearing width from its nominal size |
| T1 | Nominal effective width of cone (inner ring, with roller and cage assembly) assembled with a master cup (outer ring) |
| T2 | Nominal effective width of cup assembled with a master cone |
| ΔT1s | Deviation of minimum circumscribed size of effective width (cone assembled with a master cup) from its nominal size |
| ΔT2s | Deviation of minimum circumscribed size of effective width (cup assembled with a master cone) from its nominal size |
| Thrust bearings shaft washer | |
| d | Nominal bore diameter of shaft washer, single direction bearing |
| Δds | Deviation of a two-point size of shaft washer bore diameter from its nominal size |
| Δdmp | Deviation of a mid-range size (out of two-point sizes) of shaft washer bore diameter in any cross section from its nominal size |
| Vdsp | Range of two-point sizes of shaft washer bore diameter in any cross section |
| d2 | Nominal bore diameter of central shaft washer, double direction bearing |
| Δd2mp | Deviation of a mid-range size (out of two-point sizes) of central shaft washer bore diameter in any cross section from its nominal size |
| Vd2sp | Range of two-point sizes of central shaft washer bore diameter in any cross section |
| Si |
|
| Thrust bearings housing washer | |
| D | Nominal outside diameter of housing washer |
| ΔDs | Deviation of a two-point size of housing washer outside diameter from its nominal size |
| ΔDmp | Deviation of a mid-range size (out of two-point sizes) of housing washer outside diameter in any cross section from its nominal size |
| VDsp | Range of two-point sizes of housing washer outside diameter in any cross section |
| Se |
|
| Thrust bearings assembled bearing height | |
| T | Nominal assembled bearing height, single direction thrust bearing (except spherical roller thrust bearing → T4) |
| ΔTs | Deviation of minimum circumscribed size of assembled bearing height from its nominal size, single direction thrust bearing (except spherical roller thrust bearing → ΔT4s) |
| T1 |
|
| ΔT1s |
|
| T32) | Nominal assembled bearing height, double direction thrust bearing with seat washers |
| ΔT3s2) | Deviation of minimum circumscribed size of assembled bearing height from its nominal size, double direction thrust bearing with seat washers |
| T43) | Nominal assembled bearing height, spherical roller thrust bearing |
| ΔT4s3) | Deviation of minimum circumscribed size of assembled bearing height from its nominal size, spherical roller thrust bearing |
- 1) Modified applies to inner rings and outer rings of bearings of matched bearing sets consisting of two or more bearings. Does not apply to universally matchable angular contact ball bearings.
- 2) Not included in ISO 199:2014.
- 3) In ISO 199:2014, the symbol T is used.