Electrolytic machining method and electrolytic machining apparatus

Abstract

An electrolytic machining method includes electrolytically machining a workpiece that is positioned opposite to an electrode tool while filling an electrolytic solution between the workpiece and the electrode tool and applying a current across the workpiece and the electrode tool. The electrolytic machining is performed by having at least a part of opposing sections of the workpiece and the electrode tool immersed in the electrolytic solution reserved in a machining and storing section, while the machining surface of the workpiece is positioned at a depth of about 5 mm to about 35 mm from the surface of the electrolytic solution reserved in the machining and storing section, and by supplying the electrolytic solution to be filled in a gap at the opposing sections between the workpiece and the electrode tool.

What is claimed is:  
     
         1 . An electrolytic machining method for electrolytically machining a workpiece that is positioned opposite to an electrode tool with an electrolytic solution filled between the electrode tool and the workpiece, the method comprising the steps of: 
 immersing at least a part of an opposing section of the workpiece and the electrode tool in an electrolytic solution reserved in a machining and storing section;    positioning the opposing section of the workpiece and the electrode tool at a predetermined depth from a surface of the electrolytic solution; and    supplying the electrolytic solution to be filled in a gap at the opposing section of the workpiece and the electrode tool and electrolytically machining a machining surface of the workpiece.    
     
     
         2 . An electrolytic machining method according to  claim 1 , wherein the machining surface of the workpiece is positioned at a depth of about 5 mm to about 35 mm from the surface of the electrolytic solution retained in the machining and storing section.  
     
     
         3 . An electrolytic machining method according to  claim 1 , wherein the opposing section of the workpiece and the electrode tool is completely immersed in the electrolytic solution retained in the machining and storing section.  
     
     
         4 . An electrolytic machining method according to  claim 3 , wherein the machining surface of the workpiece is positioned at a depth of about 5 mm to about 35 mm from the surface of the electrolytic solution retained in the machining and storing section.  
     
     
         5 . An electrolytic machining method according to  claim 1 , wherein the opposing section of the workpiece and the electrode tool includes an end face section of the electrode tool that faces the machining surface of the workpiece and that is immersed in the electrolytic solution reserved in the machining and storing section.  
     
     
         6 . An electrolytic machining method according to  claim 1 , wherein the workpiece is composed of a material of a shaft member used in a dynamic pressure bearing device that utilizes a dynamic pressure of a lubricating fluid, and dynamic pressure generating grooves are formed as concave sections in the workpiece.  
     
     
         7 . An electrolytic machining method according to  claim 1 , wherein the workpiece is composed of a material of a bearing member used in a dynamic pressure bearing device that utilizes a dynamic pressure of a lubricating fluid, and dynamic pressure generating grooves are formed as concave sections in the workpiece.  
     
     
         8 . An electrolytic machining method according to  claim 1 , further comprising the step of adhering a masking member that has continuous hole patterns formed as through-holes that correspond to the shapes of the concave sections to the machining surface of the workpiece.  
     
     
         9 . An electrolytic machining method according to  claim 8 , wherein the electrolytic solution is supplied to flow in a gap between the masking member and the electrode tool to allow the electrolytic solution to enter the continuous hole patterns of the masking member and an electric current is applied across the workpiece and the electrode tool to thereby allow an electrolytic machining to take place.  
     
     
         10 . An electrolytic machining method according to  claim 1 , wherein the electrolytic solution is a mixed solution containing a surface-active agent.  
     
     
         11 . An electrolytic machining method according to  claim 1 , further comprising the step of applying ultrasonic vibration to the electrolytic solution.  
     
     
         12 . An electrolytic machining apparatus comprising: 
 an electrode tool;    a machining and storing section that reserves an electrolytic solution; and    a supporting member that retains at least a part of the electrode tool immersed in the electrolytic solution and positions a machining surface of a workpiece at a predetermined depth from a surface of the electrolytic solution stored in the machining and storing section.    
     
     
         13 . An electrolytic machining apparatus according to  claim 12 , wherein the supporting member positions the machining surface of a workpiece at a depth of about 5 mm to about 35 mm from the surface of the electrolytic solution retained in the machining and storing section.  
     
     
         14 . An electrolytic machining apparatus according to  claim 12 , further comprising a flow control device that controls charging and discharging of the electrolytic solution in and out of the machining and storing section to maintain the surface level of the electrolytic solution in the machining and storing section at a specified level.  
     
     
         15 . An electrolytic machining apparatus according to  claim 13 , wherein the workpiece is composed of a material of a shaft member used in a dynamic pressure bearing device that utilizes a dynamic pressure of a lubricating fluid.  
     
     
         16 . An electrolytic machining apparatus according to  claim 13 , wherein the workpiece is composed of a material of a bearing member used in a dynamic pressure bearing device that utilizes a dynamic pressure of a lubricating fluid.  
     
     
         17 . An electrolytic machining apparatus according to  claim 12 , wherein a masking member having continuous through-hole patterns that correspond to concave sections to be formed on the machining surface of the workpiece is adhered to the machining surface of the workpiece.  
     
     
         18 . An electrolytic machining apparatus according to  claim 12 , wherein the electrolytic solution is a mixed solution containing a surface-active agent.  
     
     
         19 . An electrolytic machining apparatus according to  claim 12 , further comprising an ultrasonic vibration generating device that provides ultrasonic vibration to the electrolytic solution.  
     
     
         20 . An electrolytic machining apparatus according to  claim 17 , wherein an insulating member is provided on at least the surface part of the masking member to substantially block energization of parts other than the continuous hole patterns of the masking member.