Non-fluidized Granular Lubrication Based On Typical Tribopair

Granular matter is widely existed in nature, and it scales from 1μm to 10~4 m. The granular lubrication means that the solid particles are directly put into the interface of tribopairs and abound in it. By utilizing friction, deformation, collision, crash, slide and rolling of these solid particles, the direct contact of two moving surfaces are minimized, and so the damage of surfaces were avoided. Granular lubrication can be used in key equipments to lubricate their important tribopairs, which can achieve low friction coefficient, wide temperature adaptation, long life and compensable granular lubrication or solid-gas lubrication. This is a kind of lubrication method and well worth further research and development.The tribological characteristics of granular lubrication which uses micro particles have been investigated based on plane contact tribotester. The results show that the continuous supply of particles formed the solid lubrication film. But the amount and the ability of particles entrancing into the clearance are hard to control. The experiments have been carried out to compare the tribological property of surfaces lubricated with copper alloy particles, bonded graphite film and PTFE three layer self lubrication material, the results demonstrate that the friction coefficient, temperature characteristics are similar. Granular lubrication has the properties of longer life and self-replenishment because they can flow in the clearance. The results also show that granular lubrication characteristics are related with particle's physical properties and running state of rubbing surfaces. A devices enables particles and air to mix and flow uniformly and transports to the tribo-pairs are constructed. Through conducting friction and wear on this machine, it testified that particles play an important role on lubrication.A model is established and the break process of the particle is simulated with discrete element method. This model can be used to simulate the plastic behaviors of the particles in clearance between rubbing surfaces. The surface topography, moving speed, clearance and internal bonding strength of particle are studied to reveal the reason of particle break and how much effect they have. This work is trying to give the mathematical model to predict the damage of particles.The experiments performed on bicircular granular lubrication equipment show the effects of surface texture and dimension of particles. While the scale of surface texture is close to particle diameter, the interaction between them is obvious and the shear and slide among granular matter are strong. While the scale of surface texture is much smaller than particle diameter, the whole particles will slide along surface. The amount of particles added in clearance takes obvious effect on tribology characteristics. The rule of the dynamic flow and distribution of granular matter needs further research.Aiming at the slider plane tribopairs and slide bearing which are typical tribological objects in mechanical engineering, the non-fluidized granular lubrication model is proposed based on discontinuous mechanics. By the discrete element simulation, the dynamic characteristics of particle film, running state of tribopair and particle physical properties have been investigated to reveal their effects on load capacity, load profile and friction coefficient. At the same time, taking particles and contact point as object, the micro-properties including average contact force, body energy, contact friction energy and particle kinetic energy of particle flow lubrication are studied. In the meantime connections between micro property of granular and macro tribopair have been discussed.