A. Universal joints in the work to bear a lot of torque and alternating load, and calcium-based grease oil film toughness is poor, in the bearing and journal friction surface is difficult to form a good oil film.

B. Universal needle cross shaft needle roller bearings in the work can only be rotated in situ, can not rotate along the steel bowl and cross shaft, and calcium-based grease rolling is poor, so when the oil film can not be destroyed immediately after the formation New oil film.

C. Calcium base grease is made of oil and calcium soap mixed in the use of lubricating oil due to deterioration and evaporation, so that grease into a hard calcium soap, calcium soap itself not only can not play a role in lubrication , But also hindered the rolling of the needle in the journal, plus the universal joint in the cross shaft and no oil removal measures, changed the quality of the grease can not be discharged, the new oil is difficult to inject, thus greatly accelerating the To the cross section of the needle bearing wear.