Movable core with valve shaft of solenoid valve and method of manufacturing the same

Abstract

A method of manufacturing a movable core having a valve shaft, of a solenoid valve with which the movable core and the valve shaft can be easily and accurately aligned with each other. The valve shaft and the movable core are manufactured by sintering as follows. First, with a lower punch inserted in a cavity of a first mold, SUS powder having an average particle diameter of 150 micrometer is put in the cavity. The powder is compacted into a powder compact in the shape of a valve shaft by lowering an upper punch into the cavity. The first mold is slightly lowered so that the powder compact slightly protrudes from the cavity. Fe powder having an average particle diameter of 150 micrometers is put in a cavity of a second mold so as to be deposited on the powder compact in the cavity of the first mold. The upper punch is lowered to compact the powder in the second mold into a powder compact in the shape of the core. After releasing the powder compacts, they are joined together by sintering.

1 . A method of manufacturing a movable core member for use in a solenoid valve, said movable core member comprising a core and a valve shaft, said solenoid valve being structured to be opened and closed by moving said valve shaft together with said core, said method comprising: 
 preparing a mold;    putting a first powder selected from a non-magnetizable powder and a mixture of a non-magnetizable powder and another powder into said mold;    compacting said first powder to form a first powder compact in the shape of said valve shaft;    putting a second powder selected from a magnetizable powder and a mixture of a magnetizable powder and another powder into said mold so as to be deposited on said first powder compact;    compacting said second powder to form a second powder compact in the shape of said core; and    sintering said first and second powder compacts to join said first and second powder compacts together, thereby forming said valve shaft from said first powder compact and said core from said second powder compact as a one-piece article.    
     
     
         2 . The movable core member manufactured by the method of  claim 1 .  
     
     
         3 . A method of manufacturing a movable core member for use in a solenoid valve, said movable core member comprising a core and a valve shaft, said solenoid valve being structured to be opened and closed by moving said valve shaft together with said core, said method comprising: 
 preparing a mold; 
 putting a first powder selected from a magnetizable powder and a mixture of a magnetizable powder and another powder into said mold;  
 compacting said first powder to form a first powder compact in the shape of said core;  
 putting a second powder selected from a non-magnetizable powder and a mixture of a non-magnetizable powder and another powder into said mold so as to be deposited on said first powder compact;  
 compacting said second powder to form a second powder compact in the shape of said valve shaft; and  
 sintering said first and second powder compacts to join said first and second powder compacts together, thereby forming said valve shaft from said second powder compact and said core from said first powder compact as a one-piece article.  
   
     
     
         4 . The movable core member manufactured by the method of  claim 3 .  
     
     
         5 . A method of manufacturing a movable core member for use in a solenoid valve, said movable core member comprising a core and a valve shaft, said solenoid valve being structured to be opened and closed by moving said valve shaft together with said core, said method comprising: 
 preparing a mold;    preparing a first powder selected from a non-magnetizable powder and a mixture of a non-magnetizable powder and another powder, said first powder being formed into the valve shaft, and a second powder selected from a magnetizable powder and a mixture of a magnetizable powder and another powder, said second powder being formed into the core;    putting one of said first and second powders into said mold;    compacting said one of said first and second powders to form a first powder compact in the shape of one of the valve shaft and the core;    putting the other of said first and second powders into said mold;    compacting said other of said first and second powders into a second powder compact in the shape of the other of the valve shaft and the core; and    sintering said first and second powder compacts to join said first and second powder compacts together, thereby forming said valve shaft from said first powder compact and said core from said second powder compact as a one-piece article.    
     
     
         6 . The method of  claim 5 , wherein said one of said first and second powders is the first powder, wherein the first powder compact is formed by compacting the first powder and has the shape of the valve shaft, wherein said other of said first and second powders is the second powder, and wherein said second powder compact is formed by compacting the second powder and has the shape of the core.  
     
     
         7 . The method of  claim 6 , wherein a valve body is integrally formed on the valve shaft by sintering.  
     
     
         8 . The method of  claim 6 , wherein said first powder comprises a stainless powder.  
     
     
         9 . The method of  claim 7 , wherein said first powder comprises a stainless powder.