Bushing Types & Material - Overview

Self-lubricating bushings are used where the bearing must operate without lubricant or with marginal lubricant. Our focus is on ensuring that the bearing gives the best performance and the longest life under various conditions. The working principle of self-lubricating bearings is that, during the initial run-in period of the bearing, there will be a solid lubricating film created by the transfer of a small amount of material from the bearing layer. This film directly contacts the moving parts, protecting and lubricating the mating components and extending the service life of the bearing.

AST has successfully supplied PTFE and thermoplastic metal-polymer bushings to the market since the very beginning. They consist of metal backing bonded to a porous bronze sintered layer with a PTFE or thermoplastic based Polymer bearing lining layer. The metal backing provides mechanical strength while the bronze sintered layer provides a strong mechanical bond between the backing and the bearing lining. The PTFE based polymer offers exceptionally low friction even under dry conditions and the thermoplastic based polymer is designed for operating with marginal lubrication. This structure promotes dimensional stability and improves thermal conductivity.

Bi-metallic material shells cover self-lubricated AST850 series and pre-lubricated AST800 series bushings. The AST850 series combines a bi-metallic shell backed with a sintered bronze alloy which is uniformly dispersed with solid lubricants. This bearing layer offers low friction and good performance under limited lubrication. The AST800 series has a steel shell backed with a lead bronze lining material for oil/grease lubricated applications. These bearing structures provide high load capacity with good fatigue properties. Tighter tolerance control can be achieved by re-machining the assembled bearing.

These bushings are wrapped from a cold formed homogenous bronze (CuSn8) with exceptional material properties. Depending on the lubrication conditions, the bearing can be provided with diamond shaped lubricant indents (for grease) or through holes (for grease or oil). With this design, a lubricant film rapidly builds up during the initial run-in period of the mating parts and thereafter running friction is considerably reduced. The AST090G material has graphite embedded into the diamond indentations to provide good lubrication conditions on start-up, even when operated with no added lubrication. This bearing design provides high load carrying capacity, good fatigue properties, dimensional stability, and improved thermal conductivity. Tighter tolerance control can be achieved by re-machining the assembled bearing.

Metallic bushing materials consist of high strength metal backing embedded with solid lubricants. The metal provides high load capacity and the solid lubricants provide low friction during operation. These bushings are precision machined with tighter tolerance to provide accurate fits after installation. This bearing design provides high load carrying capacity, good fatigue properties, dimensional stability, and improved thermal conductivity. Tighter tolerance control can be achieved by re-machining the assembled bearing.

AST CR series composite bushings consist of a continuous-wound glass fiber encapsulated in a high temperature epoxy resin with a variety of low friction wear resistant bearing linings. The reinforced composite structure enables the bearing to support high static and dynamic loads while providing excellent wear resistance. This bearing can be used for extremely high impact load applications and in highly corrosive media.

AST-EPB plastic bushings are made of a variety of resins combined with reinforcing fibers and solid lubricants to provide excellent wear resistance and low friction in both dry and lubricated operating conditions over a wide range of applications. EPB material is an economic solution for mass production designs.