Sliding material composition

Abstract

The present invention provides a sliding material composition that is capable of continuously supplying a lubricant to the surface of a sliding portion and has a low frictionality and a low wearability. A sliding material composition of the present invention includes a resin material with which at least porous silica and a lubricant are mixed. The ratio of the sum of the mixing amount of the porous silica and that of the lubricant to the whole amount of the sliding material composition is 30 to 60 vol %. The interconnected cell ratio of the oil-containing porous silica in which the lubricant is held by the porous silica is not less than 20% when the interconnected cell ratio is found by a predetermined computing method to be carried out by utilizing the principle of a Monte Carlo method.

1 . A sliding material composition comprising a resin material with which at least porous silica and a lubricant are mixed; and a ratio of a sum of a mixing amount of said porous silica and that of said lubricant to a whole amount of said sliding material composition is 30 to 60 vol %. 
   
   
       2 . The sliding material composition according to  claim 1 , wherein said porous silica is spherical porous silica, having continuous pores, which consists of an aggregate of primary fine particles; and an average particle diameter of said spherical porous silica is 0.5 to 100 μm. 
   
   
       3 . The sliding material composition according to  claim 1 , wherein an inside of said porous silica and an outer surface thereof are covered with a silanol group. 
   
   
       4 . The sliding material composition according to  claim 1 , wherein said porous silica has an oil absorption amount at 300 to 400 ml/100 g; and said porous silica is impregnated with said lubricant in advance. 
   
   
       5 . The sliding material composition according to  claim 1 , wherein said resin material is polyethylene resin. 
   
   
       6 . The sliding material composition according to  claim 1 , wherein said lubricant is silicone oil. 
   
   
       7 . The sliding material composition according to  claim 1 , wherein of 30 to 60 vol % which is said ratio of said sum of said mixing amount of said porous silica and that of said lubricant, a ratio of said mixing amount of said porous silica is 5 to 10 vol %, and a ratio of said mixing amount of said lubricant is 25 to 50 vol %. 
   
   
       8 . The sliding material composition according to  claim 1 , wherein an interconnected cell ratio of an oil-containing porous silica in which said lubricant is held by said porous silica is not less than 20% when said interconnected cell ratio is found by a predetermined computing method;
 said predetermined computing method comprises a modeling step of expressing a bulk body supposed to be composed of said oil-containing porous silica and said resin material as a model formed by layering an arbitrary number of cells one upon another in an X-axis direction and a Y-axis direction both of which are face directions and at least 25 cells one upon another in a Z-axis direction which is a depth direction, wherein said cells are cubic cells with a length of one edge thereof equal to an average particle diameter of said oil-containing porous silica;   a random disposing step of disposing cells corresponding to a mixing ratio of said oil-containing porous silica in said bulk body at random positions inside said model as oil-containing porous silica cells; and   a step of counting a number of interconnected cells of setting cells which contact each other in said model in a vertical direction, a left-to-right direction, or a longitudinal direction as continuous cells and setting an XY face composed of cells of an uppermost surface as a surface layer of said bulk body, and counting oil-containing porous silica cells of said surface layer and oil-containing porous silica cells, disposed inside said model, which are continuous from said oil-containing porous silica cells of said surface layer to oil-containing porous silica cells disposed at a depth of 25 cells as interconnected cells,   wherein a ratio of said number of interconnected cells obtained at said step of counting said number of said interconnected cells to a number of oil-containing porous silica cells present from said surface layer of said bulk body to a depth of 25 cells composing said model is computed as said interconnected cell ratio.   
   
   
       9 . The sliding material composition according to  claim 8 , wherein a number of cells used in said modeling step is not less than 30 cells in said X-axis direction, not less than 30 cells in said Y-axis direction, and a number of cells of one horizontal layer is set to not less than 1000.