Analysis Of Mechanical Properties Of Non-equal Contact Angle Paired Angular Contact Ball Bearings

Angular contact ball bearing(ACBB)is one kind of the rolling element ball bearings.Due to its high precision,high limit speed and great load capacity,ACBB is widely used in highspeed occasions.Therefore,ACBBs are always being deeply studied.Generally,ACBBs are installed in pairs.Compared with single ACBB,matched ACBBs have great advantages in terms of load bearing and service life.At present,a lot of researches have been done on matched ACBBs with the same contact angles,but seldom research focused on matched ACBBs with unequal contact angles.This article mainly studies the mechanical characteristics of matched ACBBs with unequal contact angles,and explores the possibility of their practical application.Firstly,based on Hertz contact theory and other classical bearing analysis theories,the static model of matched ACBBs with unequal contact angles is established.And,the load distribution and contact angle variation law of matched ACBBs with unequal contact angles under combined load are studied.The results show that: the axial load is mainly borne by the bearing which faces the axial load,and the increase of the axial load will make the bearing load more balance.However,the moment load and radial load will aggravate the unevenness of the bearing load.In reality,the two forces can be adjusted each other to make the bearing load uniform.Compared with the matched ACBBs with the same contact angles,it is found that the displacements of the inner rings in all of the three directions are the smallest ones when the bearing with bigger contact angle in the ACBBs with different contact angles bears the axial load directly.This shows that the unequal contact angle matching method could improve the load capacity of the ACBBs.It is very helpful to improve the bearing performance when the appropriate bearings with unequal contact angle are matched.Secondly,in the basis of the static model,the quasi-static model of matched ACBBs with unequal contact angles is also established.In this model,the influence of centrifugal force and gyroscopic moments of the balls caused by rotating speed are considered,and the dynamic performance of ACBBs is analyzed.The results show that: under the dynamic condition,the rules of the load distribution and contact angle of matched ACBBs with unequal contact angles are very close to the results obtained under static condition,but the contact forces between the balls and the outer ring are greater than those with inner ring due to the centrifugal forces.By comparing the dynamic stiffness and calorific value of bearings with the ACBB with same contact angle,the matched ACBBs with unequal contact angles has some advantages under the relatively large moment load.Finally,a test rig for matched ACBBs with unequal contact angles is built,and the axial displacement and angular displacement of inner ring of the matched ACBBs with unequal contact angles and with the same contact angle under combined load are measured.By comparing with the theoretical analysis results,it is found that the experimental results are basically consistent with the theoretical analysis results.It could be proved that the theoretical model established in this article is correct.