How tight should a bearing fit be?
tight. For a tight fit, the wheel hub inside diameter (ID) should be smaller than the outer race OD by the fit values shown on the tables. For inner race fits, the spindle OD should be smaller than the inner race bore within the loose fit range.
How do you choose a bearing fit?
When selecting fits, you should consider the following topics.
- Conditions of rotation.
- Magnitude of load.
- Temperature differences.
- Precision requirements.
- Design and material of the shaft and housing.
- Ease of mounting and dismounting.
- Axial displacement of the bearing in the non-locating position.
How tight is an interference fit?
The tightness of fit is controlled by amount of interference; the allowance (planned difference from nominal size). An example: The allowance per inch of diameter usually ranges from 0.001 to 0.0025 inches (0.0254 to 0.0635 mm) (0.1–0.25%), 0.0015 inches (0.0381 mm) (0.15%) being a fair average.
Is an example of transition fit?
Transition fit: It may sometimes provide clearance and sometimes interference. Here the tolerance zones of the hole and shaft will overlap each other. Examples: Tight fit and push-fit, wringing fit, press fit. Examples: Slide fit, easy sliding fit, running fit, slack running fit, and loose running fit.
What is the difference between a clearance fit and an interference fit?
The types of fits have been given names. They range from an interference fit, where the parts are purposely made to be forced together. This fit can be further described as heavy through to light interference. Whereas a clearance fit is for parts made to have a space between them.
What do you need to know about bearing installation?
Bearing installation guides and machinist’s handbooks will list the various types of fits and the exact dimensional tolerance for both the bearing rings, shafts and housings. If they are not within the suggested specifications, a diminished bearing life will occur.
Which is the best fit for a SKF bearing?
Where this cannot be tolerated, either protect the bearing seat surface or select a bearing that accommodates the axial displacement within itself (cylindrical roller, needle roller or CARB bearing). These bearings can be mounted with an interference fit for both rings. The ring of a SKF bearing deforms proportionately to the load.
Can a bearing be mounted with an interference fit?
These bearings can be mounted with an interference fit for both rings. The ring of a bearing deforms proportionately to the load. For rotating inner ring loads, this deformation can loosen the interference fit between the inner ring and shaft, causing the ring to creep on its shaft seat.
What are the different types of bearing fits?
Remember, measure prior to mounting. The three general types of fits are: interference or tight, line-to-line, and clearance or loose. The fit is determined by the nature of the application, load, size, type of bearing and which ring is rotating.
Why do you need a good bearing fit?
Bearing fits are critical to the reliability of rotating equipment. Application conditions including the type of driven load, the connection to that load (direct coupled or belted), and the proper bearing for the application are all factors to be considered in achieving the correct fit.
Where this cannot be tolerated, either protect the bearing seat surface or select a bearing that accommodates the axial displacement within itself (cylindrical roller, needle roller or CARB bearing). These bearings can be mounted with an interference fit for both rings. The ring of a SKF bearing deforms proportionately to the load.
How is the force required to mount a bearing determined?
The level of force required to properly mount a bearing is determined by the type and degree of press fit. In most applications, whichever ring is rotating will have the press fit. For example, an electric motor’s shaft rotates with the rotor.
Why do bearing rings need to be tightened?
Where sudden load peaks or vibration occurs, a tighter fit can be required. In operation, bearing rings normally reach a temperature that is higher than that of the components to which they are fitted. This can loosen the fit on the shaft seat, while outer ring expansion can prevent the desired axial displacement in the housing.