The clearance of crossed roller bearing will affect bearings rolling fatigue life, temperature rise, noise, vibration and other properties of the bearing. For crossed roller bearings, when the bearing clearance is too small, the most likely problems are overheating, too large starting torque, or stucking. However, if the clearance is too large, excessive noise will happen and the rotation accuracy will be reduced. So it is very important to choose the proper clearance according to the use occasion.

What is bearing internal clearance?

Internal clearance is the total distance one bearing ring moves relative to the other radially (radial internal clearance) or axially (axial internal clearance). Bearing clearance is categorized as unmounted clearance, mounted clearance and operational clearance. The bearing manufacturer establishes the initial, unmounted bearing internal clearance. It is the clearance of the bearing products that leave the factory. Mounted bearing clearance is established after the bearing is fitted onto the shaft and into the housing. When the bearing reaches steadystate operating temperature, its clearance is called operational clearance.

Ideally, for optimum bearing life and machine reliability, bearing internal clearance is zero or slightly negative at operating conditions. Initial bearing clearance is chosen during machinery design and bearing selection to reach this goal.

Clearance of Crossed Roller Bearing

The clearance of crossed roller bearings is usually measured with a dial gauge. Generally speaking, the clearance is divided into: negative clearance and positive clearance. The positive clearance can be divided into small and large type. At present, there is no relevant standard for the axial clearance, and different manufacturers have different standards and representations for the radial clearance of crossed roller bearings, such as the RU/RB/RE series of crossed roller bearings produced by THK. The clearance is divided into three types: CC0/C0/C1, and CC0 is a negative one. The CRBF/CRB/CRBH series of cross-roller bearing clearances produced by IKO are divided into three types: T1/C1/C2, among which T1 is a negative clearance.

When using crossed roller bearings, the bearing clearance should be checked regularly. If it is too large or too small, it should be adjusted as soon as possible to avoid the machine malfunction and affect the equipment.