Cylinder liner microfinishing apparatus and method

An apparatus for microfinishing an interior cylindrical surface of a workpiece, said apparatus comprising:

• holder means for holding the workpiece;
• rotation means for rotating the workpiece about an axis;
• a tool having a plurality of radially directed work areas spaced about said tool, said tool including biasing means for biasing said work areas in a radial direction;
• said work areas being spaced apart at a wrapping angle so as to enable a greater net force to be transferred to the interior cylindrical surface as said work areas are biased in said radial direction;
• a supply of abrasive film material, said abrasive film material being provided to extend substantially the length of said tool and axially over said work areas, said abrasive film material engaging and microfinishing the interior surface of the workpiece during radial biasing of said work areas;
• and
• oscillation means for oscillating said tool along said axis while said abrasive film material is engaged with the interior surface of the rotating workpiece thereby microfinishing the interior surface of the workpiece.

An apparatus for microfinishing an interior cylindrical surface of a cylinder liner, said apparatus comprising:

• a headstock having means for holding the workpiece, said headstock also including rotation means for rotating the workpiece about an axis;
• a tailstock being axially movable relative to said headstock;
• a tool supported by said tailstock and mounted for axial movement with said tailstock relative to said headstock, said tool including a first shoe and a second shoe, said first and second shoes being radially movable relative to one another in opposite directions, said shoes each having a pair of radially directed work areas, individual work areas of each of said pairs being circumferentially spaced at least ninety degrees apart from one another;
• biasing means for radially biasing said shoes apart from one another along a biasing axis;
• a first strip of abrasive film extending substantially the length of said tool and axially over one of said work areas of said first shoe member, said first strip also extending axially over one of said work areas of said second shoe;
• a second strip of abrasive film extending substantially the length of said tool and axially over the other of said work areas of said first shoe, said second strip also extending axially over the other of said work areas of said second shoe, said first and second strips of abrasive film being adapted to engage the interior cylindrical surface of the workpiece in response to radial biasing of said first and second shoes relative to one another thereby causing removal of material and microfinishing of the interior cylindrical surface of the workpiece;
• and
• reciprocating means for axially reciprocating said tool and said first and second strips of abrasive film generally along said axis while said first and second strips of said abrasive film are in contact with the interior cylindrical surface of the workpiece.

A method of microfinishing an interior cylindrical surface of a workpiece, said method comprising the steps of:

• providing a workpiece having an interior cylindrical surface to be microfinished;
• rotating said workpiece about an axis;
• providing a tool including a plurality of work areas;
• providing a supply of abrasive film remote from said tool,
• locating a strip of abrasive film material axially over each of said work areas so as to extend substantially the length of said tool;
• locating said tool and said strips of abrasive film material within said workpiece;
• actuating said tool to cause said strips of abrasive film material to engage and contact said interior cylindrical surface of said workpiece thereby microfinishing said interior cylindrical surface;
• and
• reciprocating said tool and said strips of abrasive film material along said axis as said strips of abrasive film material is in contact with said interior cylindrical surface.