How to choose bearings’ fit?

Before choosing bearing fit, we need to know about tolerance,

cause the machine processing can’t meet same size,

so it will set acceptable tolerance range for the processing item,

such as size tolerance, which means biggest tolerance size minuses smallest tolerance size.

Bearing fit can divided to three types

- Clearance fit

- Interference fit

- Transition fit

In generally situation, will choose transition fit to use, the following content will introduce three types of fit.

1.      Clearance fit

In this situation, the hole is larger than the shaft, there’s clearance between hole and shaft, can be install easily, the clearance can use to filling grease.

2.      Interference fit

In this situation, the hole is smaller than the shaft, there’s no clearance between hole and shaft, install process will need high pressure or temperature.

3.      Transition fit

In this situation, the hole is fractionally smaller than the shaft, install process will need mild force.

The following matters are the factors which would cause affect while choosing bearing fit 

1.      Temperature

While turning, bearing and shaft will generate high temperature, cause the clearance change, so choosing bearing fit need to take temperature into consideration.

2.      Load

Radius of Bearing inner ring will be extend after endure radial load, so the heavy load need to go with tighten load, if it’s impact load, it’ll need much tighter load.

3.      Load type

Rotating load can divided into two types

-inner ring

-outer ring

The load direction can also be divided into

-fixed

-rotating

The following form will recommend bearing fix for different situation.