Slide member and method for producing the slide member

Abstract

A slide member having a slide surface slidable relative to a counterpart, including a base portion and a diamond-like carbon layer formed on a surface of the base portion and provided with a plurality of microrecesses on an outer surface thereof defining the slide surface. A method for producing the slide member, including subjecting a surface of a preform of the slide member to diamond-like carbon treatment to form a diamond-like carbon layer on an outer surface of the slide member, and forming a plurality of microrecesses on an outer surface of the diamond-like carbon layer by removing microparticles from the outer surface of the diamond-like carbon layer.

1 . A slide member having a slide surface slidable relative to a counterpart under condition that a lubricating oil is supplied between the slide member and the counterpart, the slide member comprising: 
 a base portion; and    a diamond-like carbon layer formed on a surface of the base portion and provided with a plurality of microrecesses on an outer surface thereof which defines the slide surface.    
   
   
       2 . The slide member as claimed in  claim 1 , wherein the counterpart has a smoothened surface coming into slide contact with the slide member.  
   
   
       3 . The slide member as claimed in  claim 1 , wherein the microrecesses are formed at an area ratio of about 5 to 30% on the basis of an entire area of the slide surface.  
   
   
       4 . The slide member as claimed in  claim 1 , wherein the microrecesses have a maximum length of 0.1 to 5 μm.  
   
   
       5 . A slide member having a slide surface slidable relative to a cam so as to open and close an engine valve of an internal combustion engine under condition that a lubricating oil is supplied between the slide member and the cam, the slide member comprising: 
 a base portion; and    a diamond-like carbon layer formed on a surface of the base portion and provided with a plurality of microrecesses on an outer surface thereof which defines the slide surface.    
   
   
       6 . The slide member as claimed in  claim 5 , wherein the slide member is a valve lifter in an internal combustion engine, the base portion including a crown portion of the valve lifter, the diamond-like carbon layer being formed on a crown surface of the crown portion, the plurality of microrecesses being provided on the crown surface.  
   
   
       7 . The slide member as claimed in  claim 6 , wherein the microrecesses are formed at an area ratio of about 5 to 30% on the basis of an entire area of the crown surface.  
   
   
       8 . The slide member as claimed in  claim 6 , wherein the microrecesses have a maximum length of 0.1 to 5 μm.  
   
   
       9 . The slide member as claimed in  claim 6 , wherein the valve lifter is made of an iron-based metal material.  
   
   
       10 . The slide member as claimed in  claim 6 , wherein the crown surface is formed into a slightly spherical shape.  
   
   
       11 . The slide member as claimed in  claim 6 , wherein the crown portion is formed with an oil hole at a predetermined outer peripheral position thereof.  
   
   
       12 . The slide member as claimed in  claim 6 , wherein the cam is made of chilled cast iron.  
   
   
       13 . A method for producing a slide member having a slide surface slidable relative to a counterpart under condition that a lubricating oil is supplied between the slide member and the counterpart, the method comprising the steps of: 
 subjecting a surface of a preform of the slide member to diamond-like carbon treatment to form a diamond-like carbon layer on the surface of the preform; and    forming a plurality of microrecesses on an outer surface of the diamond-like carbon layer by removing microparticles from the outer surface of the diamond-like carbon layer to thereby provide the slide member with the slide surface.    
   
   
       14 . The method as claimed in  claim 13 , wherein the step of removing the microparticles is conducted by brush-lapping.  
   
   
       15 . The method as claimed in  claim 13 , wherein the step of removing the microparticles is conducted by blasting.  
   
   
       16 . The method as claimed in  claim 13 , wherein at the step of removing the microparticles, the microrecesses having a maximum length of 0.1 to 5 μm are formed on the outer surface of the diamond-like carbon layer.  
   
   
       17 . The method as claimed in  claim 13 , wherein the slide member is the valve lifter, the preform being formed by cold-forging an iron-based metal material to form the preform into a basic shape of the valve lifter.  
   
   
       18 . The method as claimed in  claim 17 , wherein the preform is subjected to heat treatment after being formed into the basic shape of the valve lifter.  
   
   
       19 . The method as claimed in  claim 18 , wherein the preform is subjected to polishing after the heat treatment.  
   
   
       20 . The method as claimed in  claim 19 , wherein the preform is washed after the polishing, and then the surface of the preform is subjected to the diamond-like carbon treatment.  
   
   
       21 . The method as claimed in  claim 13 , wherein at the step of removing the microparticles, a predetermined amount of the microparticles is removed such that the microrecesses are formed at an area ratio of about 5 to 30% on the basis of an entire area of the outer surface of the diamond-like carbon layer.