Electromagnetic vibrating diaphragm pump

Abstract

An electromagnetic vibrating diaphragm pump capable of preventing fluid such as air from leaking to an oscillator side. This diaphragm is sandwiched by an inner center plate and an outer center plate and is fixed by inserting the mounting screw parts of the oscillator into a through hole provided at the center of the outer and inner center plates. A cylindrical projecting portion is formed at the center of the inner center plate on its oscillator side, and this projecting portion is fitted into the concave groove formed at the ends of the supporting member of the oscillator so as to be sealed in an airtight manner with a ring-shaped elastic member inbetween.

What is claimed is: 
     
         1 . An electromagnetic vibrating diaphragm pump comprising:
 an oscillator having two magnets provided on at least one surface side of a plate-like supporting member made of non-magnetic material and having mounting screw parts fixed to both ends of a central axis of the supporting member;   disc-shaped diaphragms fixed to the mounting screw parts at both ends of the supporting member;   an electromagnet provided to face the magnets; and   pump casings fixed to respective outer peripheries of the diaphragms provided at the both ends and individually covering the outer side of the diaphragms,   wherein the diaphragm is sandwiched by an inner center plate provided on the magnet side of the diaphragm and an outer center plate provided on the side opposite to the magnet side of the diaphragm, the end of the oscillator is inserted into and fixed to a through hole provided at the center of the inner and outer center plates, and a cylindrical projecting portion is formed at the center of the inner center plate on the oscillator side, a concave groove capable of fitting the projecting portion is formed at the end of the supporting member of the oscillator and a ring-shaped elastic member is placed between the outer periphery of a cylindrical portion formed when the concave groove is formed and the inner periphery of the cylindrical projecting portion, such that leakage from a gap portion between the through hole of the inner and outer center plates and the end of the oscillator is prevented in an air-tight manner.   
     
     
         2 . The electromagnetic vibrating diaphragm pump according to  claim 1 , wherein a protruding portion for holding the side surfaces of both ends of the supporting member constituting the oscillator is formed on the surface of the inner center plate on its oscillator side so as to position the supporting member. 
     
     
         3 . The electromagnetic vibrating diaphragm pump according to  claim 2 , wherein the protruding portions are formed in a manner to entirely cover the outer peripheral side surface of the end of the supporting member. 
     
     
         4 . The electromagnetic vibrating diaphragm pump according to  claim 1 , wherein the concave groove is a circular concave groove terminated at the edges of side surfaces in thickness direction of the supporting member at the end. 
     
     
         5 . The electromagnetic vibrating diaphragm pump according to  claim 1 , wherein the pump casing has a compression chamber adjacent to the diaphragm, an exhaust chamber connected to the compression chamber via an exhaust valve and a suction chamber connected to the compression chamber via a suction valve, and a rib digging into the diaphragm is formed on a joint surface jointing the diaphragm on a partition wall of the compression chamber. 
     
     
         6 . The electromagnetic vibrating diaphragm pump according to  claim 5 , wherein the rib is formed to be circular and digs into a flange part formed at the end of the diaphragm in a circular manner so that the partition wall and the diaphragm are jointed. 
     
     
         7 . The electromagnetic vibrating diaphragm pump according to  claim 6 , wherein the mounting screw part is integrally fixed to the supporting member made of resin during the formation of the supporting member by resin molding. 
     
     
         8 . The electromagnetic vibrating diaphragm pump according to  claim 1 , wherein the diaphragm is formed of ethylene propylene rubber (EPDM) or fluoro-rubber compact. 
     
     
         9 . The electromagnetic vibrating diaphragm pump according to  claim 1 , wherein the magnets are permanent magnets made of a plate-like ferrite magnet or rare earth magnet. 
     
     
         10 . The electromagnetic vibrating diaphragm pump according to  claim 9 , wherein the magnets are integrally fixed to the supporting member made of resin during the formation of the supporting member by resin molding.