U-JOINT PROOF ILUSTATION

When we do u-joint proof design , there are two kinds of proof type on the bearing cup. 

First one is oil seal type ( inner oil seal type) : cost  expensive , but water and oil resistance is better. 

mostly apply on Original equiment (OEM). 

Second one is packing type (outter packing type. : cost lower , the water and oil resistance is a liite worse than 

first one. But when customer aplly on the better road istuation is not so big diffesence oil seal type. 

Two kinds of types are easily see on the market.