There are many kinds of rolling bearings used in agricultural machinery. Only taking single row radial ball bearing and single row tapered roller bearing as examples, the paper explains the identification standard of rolling bearing.

(1) Appearance inspection.

It can be inspected directly or inspected carefully with a magnifying glass. If the following damage is found, it should be replaced generally. The outer surface and inner raceway of the bearing outer ring, the inner surface and outer raceway of the inner ring, and the rolling element are worn. Generally, the outer ring and inner ring are cracked, the raceway or rolling body are pockmarked or peeled, and they will not be repaired. Only the bearing damaged by the cage can be repaired or replaced. The clearance (radial clearance, axial clearance) can only be inspected and identified without the above damage.

(2) Idling test.

Check whether the bearing rotates flexibly, whether there is excessive noise, whether there is jamming, etc. The uneven rotation of the bearing can be judged by the feeling on the hand (slight noise is allowed for the old bearing). Single row radial ball bearing has both radial and axial clearance. Due to the wear of raceway and rolling body, the radial clearance of bearing increases, and the axial clearance also increases. Generally, when the radial clearance of this kind of bearing exceeds the limit, the axial clearance also exceeds the limit. The inspection method is very simple. For the bearing with significantly increased radial clearance, the repairman can determine the size of bearing clearance by feeling.

(3) Gap measurement.

When the bearing clearance is between the allowable value without repair, it is generally unscientific to check the clearance only by feeling. Only with the help of simple tools and percentile meter can we measure. For simple tools, two cones can be used to clamp the inner ring and keep it still. Point the dial indicator contact rod to the outer ring and push the outer ring radially. The reading indicated by the dial indicator is the radial clearance of the bearing. The bearing with excessive radial clearance shall be replaced or repaired.

(4) Gap adjustment.

The clearance of single row tapered roller bearing is adjustable. In a certain period of time, the adjustment should be carried out. If the clearance is not adjusted, it will increase, which will lead to the maladjustment of the fitting relationship of the relevant parts. The inspection method of observation is the same as that of single row radial ball bearing, but it has no fixed clearance. Generally, as long as the roller is not higher than the end face of the outer ring, it can be installed, adjusted and used according to the requirements. Single row tapered roller bearings are installed in many positions of tractors. During the installation and adjustment, it should be noted that the use of single shaft adjustment can prevent the increase of clearance after the installation of false contact (virtual contact). During adjustment, it is also necessary to pay attention not to over tighten to avoid elastic deformation. If there is elastic deformation, the actual gap will be very small or no gap, although the gap is reserved according to the specified standard.

When repairing the tractor, when the spare parts are not enough, first install the best bearing on the second shaft of the gearbox, and install the bearing with large clearance on the side reducer. However, the bearing installed for the side reducer shall also be within the allowable value.