General Notes
The accuracy of the fits and the geometrically correct design of all adjacent parts have a direct effect on the accuracy requirements and the dynamic properties of the bearing.
Please observe the construction notes in the general catalogue section.
Surface Roughness Requirements
Ra 0.8 μm - Recommended surface roughness for shaft fit surfaces
Rotating Inner Ring - AXCR-U Series
The AXCR-U series has the usual bore tolerance (0/minus).
Fit Design Principles
On rotating shafts, the bearing inner ring is to be supported across its whole surface and the shaft is to be designed with a fit according to h5. In this way, the bore tolerance of the bearing generates a transition fit with a slight tendency to a clearance fit.
Maximum Accuracy Requirements
For the maximum accuracy requirement with a rotating inner ring, a clearance fit of 0 μm must be targeted; existing clearance fits can add to the radial runout.
Higher Dynamic Characteristics
In case of high speeds (ndm > 35,000 mm/min) and longer operating durations (>10%), do not exceed an interference fit of 5 μm.
Stationary Inner Ring - AXCR-U Series
Stationary, screw-connection inner rings do not require a special fit and can also be mounted with clearance to the shaft. If the inner ring is to be centred, then design:
- For AXCR-U inner rings with the usual bore tolerance (0/minus), use g6 or similar tolerance
Press fits are to be avoided due to the risk of an increase in bearing preload.
AXCR-U Series Shaft Fit Tolerance Table
| Model | Shaft Ø di [mm] | Bearing Bore Tolerance Range [mm] | Inner Ring Stationary | Inner Ring Rotating | Rmax [mm] | ||||
|---|---|---|---|---|---|---|---|---|---|
| Shaft Tolerance g6 [mm] | T1, T2, T3 [μm] | Shaft Tolerance h5 [mm] | T1 Roundness [μm] | T2 Parallelism [μm] | T3 Perpendicularity [μm] | ||||
| AXCR 80-U | 80 | 0 / -0.009 | -0.010 / -0.029 | 5 | 0 / -0.013 | 3 | 1.5 | 3 | 0.1 |
| AXCR 90-U | 90 | 0 / -0.010 | -0.012 / -0.034 | 6 | 0 / -0.015 | 4 | 2 | 4 | 0.1 |
| AXCR 115-U | 115 | 0 / -0.010 | -0.012 / -0.034 | 6 | 0 / -0.015 | 4 | 2 | 4 | 0.1 |
| AXCR 160-U | 160 | 0 / -0.013 | -0.014 / -0.039 | 8 | 0 / -0.018 | 5 | 2.5 | 5 | 0.1 |
| AXCR 210-U | 210 | 0 / -0.015 | -0.015 / -0.044 | 10 | 0 / -0.020 | 7 | 3.5 | 7 | 0.3 |
| AXCR 270-U | 270 | 0 / -0.018 | -0.017 / -0.049 | 12 | 0 / -0.023 | 8 | 4 | 8 | 0.3 |
| AXCR 350-U | 350 | 0 / -0.023 | -0.018 / -0.054 | 13 | 0 / -0.025 | 9 | 4.5 | 9 | 0.3 |
| AXCR 360-U | 360 | 0 / -0.023 | -0.018 / -0.054 | 13 | 0 / -0.025 | 9 | 4.5 | 9 | 0.3 |
| AXCR 540-U | 540 | 0 / -0.030 | -0.022 / -0.066 | 16 | 0 / -0.032 | 11 | 5.5 | 11 | 0.3 |
Rotating Inner Ring - AXCR-S Series
The AXCR-S series has bore tolerance (0/plus).
Fit Design Principles
On rotating shafts, the bearing inner ring is to be supported across its whole surface and the shaft is to be designed with a fit according to k5. In this way, the bore tolerance of the bearing generates a transition fit with a slight tendency to a clearance fit.
In case of designs with clearance fits, see the guidelines in the Adjacent Construction chapter.
Maximum Accuracy Requirements
For the maximum accuracy requirement with a rotating inner ring, a clearance fit of 0 μm must be targeted; existing clearance fits can add to the radial runout.
Higher Dynamic Characteristics
In case of high speeds (ndm > 35,000 mm/min) and longer operating durations, do not exceed an interference fit of 5 μm.
Stationary Inner Ring - AXCR-S Series
Stationary, screw-connection inner rings do not require a special fit and can also be mounted with clearance to the shaft. If the inner ring is to be centred, then design:
- For AXCR-S inner rings with bore tolerance (0/plus), use j6 or similar tolerance
Press fits are to be avoided due to the risk of an increase in bearing preload.
AXCR-S Series Shaft Fit Tolerance Table
| Model | Shaft Ø di [mm] | Bearing Bore Tolerance Range [mm] | Inner Ring Stationary | Inner Ring Rotating | Rmax [mm] | ||||
|---|---|---|---|---|---|---|---|---|---|
| Shaft Tolerance j6 [mm] | T1, T2, T3 [μm] | Shaft Tolerance k5 [mm] | T1 Roundness [μm] | T2 Parallelism [μm] | T3 Perpendicularity [μm] | ||||
| AXCR 130-S | 130 | 0 / +0.025 | +0.014 / -0.011 | 8 | +0.021 / +0.003 | 5 | 2.5 | 5 | 0.1 |
| AXCR 150-S | 150 | 0 / +0.025 | +0.014 / -0.011 | 8 | +0.021 / +0.003 | 5 | 2.5 | 5 | 0.1 |
| AXCR 180-S | 180 | 0 / +0.025 | +0.014 / -0.011 | 8 | +0.021 / +0.003 | 5 | 2.5 | 5 | 0.1 |
| AXCR 220-S | 220 | 0 / +0.029 | +0.016 / -0.013 | 10 | +0.024 / +0.004 | 7 | 3.5 | 7 | 0.3 |
| AXCR 280-S | 280 | 0 / +0.032 | +0.016 / -0.016 | 12 | +0.027 / +0.004 | 8 | 4 | 8 | 0.3 |
| AXCR 360-S | 360 | 0 / +0.036 | +0.018 / -0.018 | 13 | +0.029 / +0.004 | 9 | 4.5 | 9 | 0.3 |
Shaft Fit Dimension Diagram
Dimension Symbol Legend
- di - Bearing bore / shaft diameter
- T1 - Roundness tolerance
- T2 - Parallelism tolerance
- T3 - Perpendicularity tolerance
- Rmax - Maximum corner radius
- g6, h5 - AXCR-U shaft tolerance ranges
- j6, k5 - AXCR-S shaft tolerance ranges
Notes
Important: Shaft Surface Quality
- Surface roughness: Ra ≤ 0.8 μm
- Roundness: According to model requirements (see table above)
- Parallelism: Should be within the tolerance range
- Perpendicularity: Perpendicularity of the shaft shoulder to the shaft journal is important
- The above data are recommended values; adjustments may be required based on specific application conditions
- High-precision applications may require tighter tolerances
- All mating surfaces should be cleaned and inspected before installation
- For clearance fit design, please refer to the guidelines in the Adjacent Construction chapter