Plunger Type High-Pressure Fuel Pump

Abstract

A plunger type high-pressure fuel pump includes a plunger reciprocated in a cylinder. A fluid pressurizing chamber of the pump has a chamber with a capacity that changes with reciprocation of the plunger. An electromagnetic valve is provided between the pressurizing chamber and a fluid suction passage; as well as a discharge valve. The electromagnetic valve includes a valve member including a suction valve; a solenoid coil adapted to displace the valve member; an anchor made of a magnetic material provided integrally with the valve member; and a core forming a magnetic circuit to attract the anchor by the electromagnetic force and dividing the inside of the electromagnetic valve into an internal space and an external space communicating with the fluid suction passage. The anchor or the core is provided with a fluid passage through which fluid can flow between the internal space and the external space formed by the anchor and the core, respectively, when the suction valve is in an opened state.

What is claimed is: 
     
         1 . A plunger type high-pressure fuel pump comprising:
 a cylinder provided in the pump;   a plunger provided slidably in the cylinder and reciprocated according to rotation of a cam;   a fluid pressurizing chamber formed by the plunger and the cylinder;   an electromagnetic valve provided in a space formed between the pressurizing chamber and a fluid suction passage; and   a discharge valve provided in a space formed between the pressurizing chamber and a fluid discharge passage;   wherein the electromagnetic valve includes:
 a valve member, including a suction valve, opening and closing an inlet side of the pressurizing chamber; 
 an elastic member for biasing the valve member in a valve-closing direction; 
 a solenoid coil adapted to displace the valve member in an opening direction; 
 an anchor made of a magnetic material operated by electromagnetic force of the solenoid coil, integrally provided with the valve member; and 
 a core forming a magnetic circuit to attract the anchor in an opening direction by the electromagnetic force and dividing the inside of the electromagnetic valve into a hermetically closed space and an external space communicating with the fluid suction passage; and 
   wherein the anchor or the core is provided with a fluid passage through which fluid can flow between the hermetically closed space and the external space formed by the anchor and the core, when the suction valve is in an opened state.   
     
     
         2 . The plunger type high-pressure fuel pump according to  claim 1 , wherein the core has an insertion port to insert the valve member into at a central portion of the core, the core has an abutment surface in abutment against the anchor on the outside of the insertion port, and a radial fluid passage-groove is formed on the abutment surface. 
     
     
         3 . The plunger type high-pressure fuel pump according to  claim 1 , wherein the anchor has an abutment surface in abutment against the fixed core, a radial fluid passage-groove is formed on the abutment surface, and fluid in the hermetically closed space communicates with the external space via the fluid passage-groove of the anchor and via a clearance between the core and the valve member. 
     
     
         4 . The plunger type high-pressure fuel pump according to  claim 1 , wherein the core has an insertion port to insert the valve member into at a central portion of the core, the core has an abutment surface in abutment against the anchor on the outside of the insertion port, the core has a non-abutment surface in non-abutment against the anchor on the outside of the abutment surface, and a fluid passage hole is formed in the core between the non-abutment surface and a surface in contact with the external space. 
     
     
         5 . The plunger type high-pressure fuel pump according to  claim 1 , wherein the anchor has an abutment surface facing to and abutting against the core inserted into the valve member, and a fluid passage hole is formed in the anchor between the abutment surface of the anchor facing to a clearance between the core and the valve member and a surface of the anchor in contact with the hermetically closed space. 
     
     
         6 . The plunger type high-pressure fuel pump according to  claim 1 , wherein
 the core has an insertion port to insert the valve member into a central portion of the core, the core has an abutment surface in abutment against the anchor on the outside of the insertion port, and the abutment surface is provided with a plating surface to be plated,   the anchor has an abutment surface in abutment against the fixed core, and the abutment surface is provided with a plating surface to be plated, and   at least one of the plated surface of the core and the plated surface of the anchor is provided with a radial fluid passage groove.