Tolerances for cast iron and steel housings – seats for radial bearings1)
| Conditions |
Dimensional
tolerance2) |
Total radial
run-out tolerance |
Total axial
run-out tolerance |
Ra6) | Displacement
of outer ring |
|
| – | – | – | µm | – | ||
| For non-split housings only | Rotating outer ring load | |||||
| Heavy loads on bearings in thin-walled housings,
heavy peak loads (P > 0,1 C) |
P7 | IT6/2 | IT6 | 3,2 | Cannot be displaced | |
| Normal to heavy loads (P > 0,05 C) | N7 | IT6/2 | IT6 | 3,2 | Cannot be displaced | |
| Light and variable loads (P = 0,05 C) | M7 | IT6/2 | IT6 | 3,2 | Cannot be displaced | |
| Direction of load indeterminate | ||||||
| Heavy peak loads | M7 | IT6/2 | IT6 | 3,2 | Cannot be displaced | |
| Normal to heavy loads (P > 0,05 C),
axial displacement of outer ring unnecessary |
K75) | IT6/2 | IT6 | 3,2 | In most cases,
cannot be displaced |
|
| For non-split housings
and split housings |
Direction of load indeterminate | |||||
| Light to normal loads (P = 0,1 C),
axial displacement of outer ring desirable |
J7 | IT6/2 | IT6 | 3,2 | In most cases,
can be displaced |
|
| Stationary outer ring load | ||||||
| Loads of all kinds | H73) | IT6/2 | IT6 | 3,2 | Can be displaced | |
| Light to normal loads (P = 0,1 C)
with simple working conditions |
H83) | IT6/2 | IT6 | 3,2 | Can be displaced | |
| Thermal expansion of the shaft | G74) | IT6/2 | IT6 | 3,2 | Can be displaced | |
-
1)
For drawn cup, alignment and combined needle roller bearings:
- Drawn cup needle roller bearings
- Alignment needle roller bearings
- Combined needle roller bearings
- 2) The envelope requirement (symbol Ⓔ from ISO 14405-1) is not shown but applies to all tolerance classes.
- 3) For large bearings (D > 250 mm), or temperature differences between the outer ring and housing > 10 °C (18 °F), tolerance class G7Ⓔ should be used instead of tolerance class H7Ⓔ.
- 4) For large bearings (D > 500 mm), or temperature differences between the outer ring and housing > 10 °C (18 °F), tolerance class F7Ⓔ should be used instead of tolerance class G7Ⓔ.
- 5) A split housing is allowed provided housing halves are well aligned during machining of the housing, with relief chamfers at the split.
- 6) For D > 500 mm, use Ra = 6,3 µm.
