Machine tool and bed structure thereof

Abstract

A machine tool includes X-axis, Y-axis, and Z-axis moving units for producing relative movements between a tool and a workpiece; a C-axis drive unit for rotating the workpiece about a C-axis parallel to the Z-axis; and a B-axis turning unit for turning the tool about a B-axis parallel to the Y-axis. The tool is disposed in such a manner that a machining point of the tool coincides with the B-axis. The moving units, the drive unit, and the turning unit are controlled in such a manner that a work point of the workpiece coincides with the machining point of the tool. The bed is formed through casting and has a hollow structure and a hole as cast; and a cover is provided to cover the hole as cast in order to close the interior of the bed.

1 - 7 . (canceled)  
   
   
       8 . A bed structure for a machine tool, comprising: 
 a bed formed through casting, the bed having a hollow structure and at least one hole as cast; and    a cover for covering each said at least one hole as cast in order to close the interior of the bed, wherein said cover substantially prevents the passage of air.    
   
   
       9 . A bed structure for a machine tool, comprising: 
 a bed formed through casting, the bed having a hollow structure and a hole as cast; and    a cover for covering the hole as cast in order to close the interior of the bed, wherein a liquid is charged into the interior of the bed.    
   
   
       10 . A bed structure according to  claim 9 , wherein the liquid is oil, or water containing a rust preventing agent.