Especially suitable for heavy low speed rotary motion, oscillating motion, and often not easy to open and close under load to form the site of fluid lubrication; in the boundary lubrication conditions can be long-term use without refueling and maintenance, and refueling process allows the use of bearings Life can be more extended; the surface of the plastic layer forming the sleeve can be left a certain margin, pressure after opening their own processing, in order to achieve better assembly size. 
 Now mainly used in metallurgical machinery, mining machinery, irrigation machinery, automobile chassis, construction machinery, agricultural machinery, steel rolling machinery.