Crankshaft bearing

- Jul 27, 2020-

Bearing length

The new bearing is installed in the housing hole, and each end of the upper and lower pieces should be 0.03-0.05mm higher than the plane of the bearing housing. In order to ensure that the bearing bush and the seat hole closely fit, improve the heat dissipation effect.

The empirical method for checking the length of the bearing shell is: install the bearing shell, install the bearing shell cover, tighten the bolt at one end according to the specified torque value, insert a gasket with a thickness of 0.05mm between the other end cover and the bearing seat plane, when tightening the bolt torque at this end When it reaches 10-20N·m, if the gasket cannot be pulled out, it indicates that the bearing length is too long, and the end without positioning tenon should be filed down; if the gasket can be pulled out, it indicates that the length of the bearing bush is suitable; if it is not screwed to the specified torque If the value gasket cannot be extracted, it means that the bearing bush is too short and should be re-selected.

Good smooth lug on the back

There should be no spots on the back of the bearing, and the surface roughness Ra is 0.8μm. The tenon can prevent the bearing from rotating and play a positioning role. If the tenon is too low, the tip can be used to impact the ideal height. If the tenon is damaged, the bearing should be reselected.

Suitable for elasticity without muting

After the new bearing shell is put on the bearing shell seat, the radius of curvature of the bearing shell is required to be greater than the radius of curvature of the seat hole. After the bearing shell is installed in the seat hole, the elastic force of the bearing shell itself can be closely attached to the bearing seat hole to facilitate heat dissipation. Check whether there is a dull sound on the bearing bush. You can tap the back of the bearing bush to check. If there is a dull sound, it indicates that the alloy and the bottom plate are not firmly combined.

The matching clearance of the bearing journal should be appropriate

When selecting the bearing bush, its fit clearance must be checked. During the inspection, measure the bearing bush and journal with the measuring cylinder meter and micrometer, and the difference is the fit clearance. The inspection method of the matching clearance of the bearing bush is: for the connecting rod bush, apply a thin layer of engine oil on the bearing bush, put the connecting rod on the corresponding journal, tighten the bolts according to the specified torque value, and then shake the connecting rod by hand to turn it 1~1/2 turns, pull the connecting rod along the axial direction, there is no feeling of gap, which meets the requirements; for the crankshaft, coat the surface of each journal and crane bearing with oil, install the crankshaft and tighten the bolts according to the specified torque value with both hands Pull the crankshaft so that the crankshaft can rotate 1/2 turn, and the rotation is light, uniform and without blocking.