Method of processing valve mechanism

Abstract

A method of processing a valve mechanism which includes a valve body having a shut-off surface in the form of a convex spherical surface, a valve hole, a valve seat formed by an opening of the valve hole, and a spring which urges the valve body toward the valve seat, wherein the valve mechanism is so formed that the valve body resists the urging force of the spring in accordance with the pressure increase in the valve hole to be separate from the valve seat, includes the steps of: preparing a processing tool having a processing surface in the form of a convex spherical surface which has the same curvature radius as the shut-off surface of the valve body; positioning the processing tool to the valve seat; and forming the valve seat along the form of the processing surface by pushing the processing surface of the processing tool against the valve seat.

1 . A method of processing a valve mechanism which includes a valve body having a shut-off surface in the form of a convex spherical surface, a valve hole whose opening degree is adjusted by the valve body, a valve seat formed by an opening of the valve hole, and a spring which urges the valve body toward the valve seat, the valve mechanism being so formed that the valve body resists the urging force of the spring in accordance with the pressure increase in the valve hole to be separate from the valve seat, the method comprising the steps of: 
 preparing a processing tool having a processing surface in the form of a convex spherical surface which has the same curvature radius as the shut-off surface of the valve body;    positioning the processing tool to the valve seat; and    forming the valve seat along the form of the processing surface by pushing the processing surface of the processing tool against the valve seat.    
   
   
       2 . The method according to  claim 1 , wherein the valve body is used for the processing tool.  
   
   
       3 . The method according to  claim 1 , wherein a member different from the valve body is used for the processing tool.  
   
   
       4 . The method according to  claim 1 , wherein the valve mechanism is a relief valve for use in a hydraulic circuit.  
   
   
       5 . The method according to  claim 4 , wherein the hydraulic circuit is a refrigerating circuit for an air conditioner, the refrigerating circuit using a carbon dioxide as a refrigerant.  
   
   
       6 . The method according to  claim 1 , wherein the force that pushes the processing tool against the valve seat is set so as to have the value more than that of the spring that pushes the valve body against the valve seat, under the circumstances where pressure differential is not applied to the valve body.  
   
   
       7 . The method according to  claim 1 , further comprising the step of: 
 plating the valve seat after the forming process of the valve seat.    
   
   
       8 . A tool for processing a valve seat being used upon processing a valve mechanism which includes a valve body having a shut-off surface in the form of a convex spherical surface, a valve hole whose opening degree is adjusted by the valve body, the valve seat formed by an opening of the valve hole, and a spring which urges the valve body toward the valve seat, the valve mechanism being so formed that the valve body resists the urging force of the spring in accordance with the pressure increase in the valve hole to be separate from the valve seat, comprising: 
 a processing surface in the form of a convex spherical surface having the same curvature radius as the shut-off surface of the valve body.    
   
   
       9 . The processing tool according to  claim 8 , wherein the processing surface of the processing tool is the shut-off surface of the valve body.