High-pressure fuel feed pump

Abstract

A high-pressure fuel feed pump, wherein a pump housing is formed of an aluminum alloy, a cylinder is formed of iron base metal, the flange part of a flanged tube member is held in a contact part between the pump housing and the cylinder, the tube member is installed in the pump housing along the inner wall surface thereof. As a result, a seal surface is not corroded directly since cavitation occurs between the tip of the tube member and the pump housing.

1 . A high-pressure fuel feed pump comprising: 
 a first member provided with a recess;    a second member assembled to the first member and defining said recess into a pressurization chamber;    a plunger reciprocatively supported by the second member, wherein the plunger advances and retreats in said pressurization chamber to pressurize fuel;    a sheet-shaped intermediate member, having an annular surface interposed between the first member and the second member, and a cylindrical part extending along the direction which advances and retreats the plunger at the inner periphery of the annular surface,    wherein the cylindrical part thereof is press-fitted into the recess of said first member, and the annular part thereof is pressure-welded to said first member and second member to form a seal; and    a pressing mechanism for relatively pressing said first member and said second member against the annular part of said intermediate member.    
     
     
         2 . A high-pressure fuel feed pump comprising: 
 a metallic housing provided with a recess;    a metallic cylindrical body secured to the metallic housing and defining said recess into a pressurization chamber, wherein the metallic cylindrical body has a higher hardness than the metallic housing;    a plunger reciprocatively supported by the metallic cylindrical body, wherein the plunger advances and retreats in said pressurization chamber to pressurize fuel;    a sheet-shaped intermediate member, having an annular surface interposed between the metallic housing and the metallic cylindrical body, and a cylindrical part extending along the direction which advances and retreats the plunger at the inner periphery of the annular surface,    wherein the cylindrical part thereof is press-fitted into the recess of said metallic housing, and the annular part is pressure-welded to said metallic housing and said metallic cylindrical body to form a seal; and    a pressing mechanism for relatively pressing said first member and second member against the annular part of said intermediate member.    
     
     
         3 . The high-pressure fuel feed pump according to any one of claims  1  and  2 , wherein said intermediate member is formed of a material having a lower hardness than said second member and said metallic cylindrical body.  
     
     
         4 . A high-pressure fuel feed pump comprising: a plunger for forcibly feeding fuel in a pressurization chamber, a suction valve provided at the inlet of the pressurization chamber, a discharge valve provided at the outlet of the pressurization chamber, and a low-pressure chamber provided at the upstream side of the suction valve, a cylinder for slidably holding the plunger and a housing for forming some of fuel passages being separately formed; characterized in that 
 the pressurization chamber is formed by pressure-welding the housing and other members, and a fuel chamber is provided outside the pressure-welded part.    
     
     
         5 . The high-pressure fuel feed pump according to  claim 4 , wherein the pressure-welding member is formed of a material having a higher hardness than that of said housing.  
     
     
         6 . The high-pressure fuel feed pump according to  claim 4 , wherein said pressure-welding member is provided with two or more pressure-welded surfaces to be pressure-welded with said housing.  
     
     
         7 . The high-pressure fuel feed pump according to  claim 6 , wherein the two pressure-welded surfaces are a cylindrical surface and a flat surface.  
     
     
         8 . A high-pressure fuel feed pump comprising: a plunger for forcibly feeding fuel in a pressurization chamber, a suction valve provided at the inlet of the pressurization chamber, a discharge valve provided at the outlet of the pressurization chamber, and a low-pressure chamber provided at the upstream side of the suction valve, a cylinder for slidably holding the plunger and a housing for forming some of fuel passages being separately formed; characterized in that 
 the pressurization chamber is formed by pressure-welding the housing and other members, and a second pressure-welded part is provided outside the pressurization chamber of the pressure-welded part (first pressure-welded part).    
     
     
         9 . The high-pressure fuel feed pump according to  claim 5 , wherein the hardness of the second pressure-welding member is softer than that of the first welding member.  
     
     
         10 . The high-pressure fuel feed pump according to  claim 5 , wherein the hardness of the second pressure-welding member is softer than that of the housing.  
     
     
         11 . A high-pressure fuel feed pump comprising: a plunger for forcibly feeding fuel in a pressurization chamber, a suction valve provided at the inlet of the pressurization chamber, a discharge valve provided at the outlet of the pressurization chamber, and a low-pressure chamber provided at the upstream side of the suction valve, a cylinder for slidably holding the plunger and a housing for forming some of fuel passages being separately formed; characterized in that 
 the pressurization chamber is provided in the housing, and a partition wall between the low-pressure chamber and the pressurization chamber is the most weakened in strength among all of the walls of the pressurization chamber.    
     
     
         12 . A high-pressure fuel feed pump comprising: a plunger for forcibly feeding fuel in a pressurization chamber, a suction valve provided at the inlet of the pressurization chamber, a discharge valve provided at the outlet of the pressurization chamber, and a low-pressure chamber provided at the upstream side of the suction valve, a cylinder for slidably holding the plunger and a housing for forming some of fuel passages being separately formed; characterized in that 
 the pressurization chamber is formed by pressure-welding the housing and other members, and space is provided in a part of the pressure-welded surface.    
     
     
         13 . The high-pressure fuel feed pump according to  claim 9 , wherein the pressure-welded surface is divided into two or more sections by said space.  
     
     
         14 . A high-pressure fuel feed pump comprising: a plunger for forcibly feeding fuel in a pressurization chamber, a suction valve provided at the inlet of the pressurization chamber, a discharge valve provided at the outlet of the pressurization chamber, and a low-pressure chamber provided at the upstream side of the suction valve, a cylinder for slidably holding the plunger and a housing for forming some of fuel passages being separately formed; characterized in that 
 the pump comprises a cylinder holder for fixing said cylinder, and an engaging part C between the cylinder holder and said housing is provided between a cylinder fixing part A at the housing side and a cylinder fixing part B at the cylinder holder side.    
     
     
         15 . The high-pressure fuel feed pump according to  claim 14 , wherein a fitting part D, where the inner diameter of said cylinder holder and the outer diameter of said cylinder are radially fitted, is provided at a position different from that of the engaging part C on the axis of said cylinder.  
     
     
         16 . The high-pressure fuel feed pump according to  claim 15 , wherein the cylinder holder is engaged with a sealing member for sealing a sliding part of said plunger.  
     
     
         17 . A high-pressure fuel feed pump comprising: a plunger for forcibly feeding fuel in a pressurization chamber, a suction valve provided at the inlet of the pressurization chamber, a discharge valve provided at the outlet of the pressurization chamber, and a low-pressure chamber provided at the upstream side of the suction valve, a cylinder for slidably holding the plunger and a housing for forming some of fuel passages being separately formed; characterized in that 
 the pump comprises a cylinder holder for fixing said cylinder, and a fitting part B fitted with the cylinder is provided inside the cylinder holder.    
     
     
         18 . The high-pressure fuel feed pump according to  claim 17 , wherein chambers having different pressure are formed in said fitting part B.  
     
     
         19 . The high-pressure fuel feed pump according to  claim 17 , wherein said cylinder holder is engaged with said housing and the engaging part C is positioned closer to the opening end of the cylinder holder than said fitting part B.  
     
     
         20 . The high-pressure fuel feed pump according to  claim 18 , wherein a radial fitting part D between said cylinder holder and said cylinder is provided between said engaging part C and said fitting part B.  
     
     
         21 . A high-pressure fuel feed pump comprising: a plunger for forcibly feeding fuel in a pressurization chamber, a suction valve provided at the inlet of the pressurization chamber, a discharge valve provided at the outlet of the pressurization chamber, and a low-pressure chamber provided at the upstream side of the suction valve, a cylinder for slidably holding the plunger and a housing for forming some of fuel passages being separately formed; characterized in that 
 the pump comprises a cylinder holder for fixing said cylinder, and the outer peripheral part of the cylinder holder is provided with a threaded part engaging said housing.  
 
     
     
         22 . The high-pressure fuel feed pump according to  claim 21 , wherein said threaded part is coated with resin.  
     
     
         23 . A high-pressure fuel feed pump comprising: a plunger for forcibly feeding fuel in a pressurization chamber, a suction valve provided at the inlet of the pressurization chamber, a discharge valve provided at the outlet of the pressurization chamber, and a low-pressure chamber provided at the upstream side of the suction valve, a cylinder for slidably holding the plunger and a housing for forming some of fuel passages being separately formed; characterized in that 
 an annular fuel chamber is formed at the outer peripheral part of the cylinder, and the fuel chamber communicates with the low-pressure chamber.    
     
     
         24 . A high-pressure fuel feed pump comprising: a plunger for forcibly feeding fuel in a pressurization chamber, a suction valve provided at the inlet of the pressurization chamber, a discharge valve provided at the outlet of the pressurization chamber, a low-pressure chamber provided at the upstream side of the suction valve, and a cylinder for slidably holding the plunger, characterized in that 
 a sealing member is arranged to seal the sliding part of said plunger, and the inner side of the sealing member inside the pump is formed as a blind passage that communicates with the low-pressure chamber by way of a sliding gap X of said cylinder and said plunger.    
     
     
         25 . A high-pressure fuel feed pump comprising: a plunger for forcibly feeding fuel in a pressurization chamber, a suction valve provided at the inlet of the pressurization chamber, a discharge valve provided at the outlet of the pressurization chamber, a low-pressure chamber provided at the upstream side of the suction valve, and a cylinder for slidably holding the plunger, characterized in that 
 a sealing member is arranged to seal the sliding part of said plunger, the inner side of sealing member inside the pump communicates with the low-pressure chamber by way of a sliding gap X of said plunger, and the length of the sliding gap X is shorter than the reciprocatively sliding length of the plunger.    
     
     
         26 . A high-pressure fuel feed pump comprising: a plunger for forcibly feeding fuel in a pressurization chamber, a suction valve provided at the inlet of the pressurization chamber, a discharge valve provided at the outlet of the pressurization chamber, a low-pressure chamber provided at the upstream side of the suction valve, and a cylinder for slidably holding the plunger, characterized in that 
 a sealing member is arranged to seal the sliding part of said plunger, the inner side of sealing member inside the pump communicates with a chamber approximately at atmospheric pressure, and a throttle part is provided in a part of the communication passage.    
     
     
         27 . A high-pressure fuel feed pump comprising: a plunger for forcibly feeding fuel in a pressurization chamber, a suction valve provided at the inlet of the pressurization chamber, a discharge valve provided at the outlet of the pressurization chamber, a low-pressure chamber provided at the upstream side of the suction valve, and a cylinder for slidably holding the plunger, characterized in that 
 wherein a sealing member is arranged to seal the sliding part of said plunger, and the inner side of the sealing member inside the pump is provided with a lubricant reservoir.    
     
     
         28 . A high-pressure fuel feed pump comprising: a plunger for forcibly feeding fuel in a pressurization chamber, a suction valve provided at the inlet of the pressurization chamber, a discharge valve provided at the outlet of the pressurization chamber, a low-pressure chamber provided at the upstream side of the suction valve, and a cylinder for slidably holding the plunger, characterized in that 
 an actuator is provided to execute the electronic control of the opening and closing timing of the suction valve, an annular fuel chamber is formed at the outer peripheral part of the actuator; and the fuel chamber communicates with the low-pressure chamber.    
     
     
         29 . The high-pressure fuel feed pump according to  claim 28 , wherein the pump further comprises an actuator holder for fixing said actuator, and the outer peripheral part of the actuator holder is provided with a threaded part engaging said housing.  
     
     
         30 . The high-pressure fuel feed pump according to  claim 29 , the threaded part is coated with resin.  
     
     
         31 . A high-pressure fuel feed pump comprising: a plunger for forcibly feeding fuel in a pressurization chamber, a suction valve provided at the inlet of the pressurization chamber, a discharge valve provided at the outlet of the pressurization chamber, and an actuator for electronically controlling the opening and closing timing of the suction valve; characterized in that 
 the driving current of the actuator is gradually reduced at the time of OFF.    
     
     
         32 . A high-pressure fuel feed pump comprising: a plunger for forcibly feeding fuel in a pressurization chamber, a suction valve provided at the inlet of the pressurization chamber, a discharge valve provided at the outlet of the pressurization chamber, and an actuator for electronically controlling the opening and closing timing of the suction valve; characterized in that 
 the driving part of the actuator and the suction valve are separately formed, and the operation distance of said actuator driving part is made shorter than that of the suction valve.    
     
     
         33 . A high-pressure fuel feed pump comprising: a plunger for forcibly feeding fuel in a pressurization chamber, a suction valve provided at the inlet of the pressurization chamber, a discharge valve provided at the outlet of the pressurization chamber, and an actuator for electronically controlling the opening and closing timing of the suction valve; characterized in that 
 the operation distance of said discharge valve is regulated to be equal to or shorter than that of the suction valve.    
     
     
         34 . A high-pressure fuel feed pump comprising: a plunger for forcibly feeding fuel in a pressurization chamber, a suction valve provided at the inlet of the pressurization chamber, and a discharge valve provided at the outlet of the pressurization chamber, characterized in that 
 at least one of said suction valve and discharge valve is formed as a ball valve and a cylindrical member is provided to be fitted with the ball valve, and the outer peripheral part of the cylindrical part is slidably held in the inner diameter side of a cylindrical member holding member.    
     
     
         35 . The high-pressure fuel feed pump according to  claim 34 , wherein a part of the outer diameter of the cylindrical member is provided with notches for forming fuel passages.  
     
     
         36 . A high-pressure fuel feed pump comprising: a plunger for forcibly feeding fuel in a pressurization chamber, a suction valve provided at the inlet of the pressurization chamber, and a discharge valve provided at the outlet of the pressurization chamber; characterized in that 
 at least one of said suction valve and discharge valve is formed as a flat valve, having a cup-shaped cylindrical part, and the outer peripheral part of the cylindrical part is slidably held in the inner diameter side of a cylindrical part holding member.    
     
     
         37 . The high-pressure fuel feed pump according to  claim 36 , wherein a part of the inner diameter of the cylindrical part holding member is provided with notches for forming fuel passages.  
     
     
         38 . A high-pressure fuel feed pump comprising: a plunger for forcibly feeding fuel in a pressurization chamber, a suction valve provided at the inlet of the pressurization chamber, a discharge valve provided at the outlet of the pressurization chamber, and a low-pressure chamber provided at the upstream side of the suction valve, a cylinder for slidably holding the plunger and a housing for forming some of fuel passages being separately formed; characterized in that 
 a cylindrical tube material is used in a part of the pressurization chamber.    
     
     
         39 . The high-pressure fuel feed pump according to  claim 38 , wherein the cylindrical tube material is a flange.  
     
     
         40 . The high-pressure fuel feed pump according to  claim 38 , wherein the cylindrical tube member is held by pressure-welding.  
     
     
         41 . The high-pressure fuel feed pump according to  claim 40 , wherein the pressure-welded part of the cylindrical tube member is formed at two positions on a cylindrical surface and a flat surface.  
     
     
         42 . A high-pressure fuel feed pump comprising: a plunger for forcibly feeding fuel in a pressurization chamber, a suction valve provided at the inlet of the pressurization chamber, a discharge valve provided at the outlet of the pressurization chamber, a low-pressure chamber provided at the upstream side of the suction valve, and a cylinder which holds the plunger slidably; characterized in that 
 a plurality of sealing members is provided to seal the sliding part of the plunger.    
     
     
         43 . The high-pressure fuel feed pump according to  claim 42 , wherein the plurality of sealing members are formed in different shapes, and a party of them are formed in a lip shape.  
     
     
         44 . The high-pressure fuel feed pump according to  claim 43 , wherein the lip-shaped sealing members are provided outside the pump in relation to the other party of the sealing members.  
     
     
         45 . The high-pressure fuel feed pump according to  claim 44 , wherein the housing is formed of a soft material.