Fuel supply pump

Abstract

The invention provides fuel supply pump that can improve the durability of a fuel inlet valve and stably pressure-feed high pressure fuel of a large flow rate. In the fuel inlet valve according to the invention, a valve piston includes, in its outer surface in the vicinity of an end portion on an opposite side of a collar portion, a groove portion to which a fastener for fixing the valve piston and a spring seat locks. The spring seat includes an open portion into which the valve piston is inserted and includes, along an edge of the open portion, a step portion to which the fastener locks. The valve piston is inserted into the open portion of the spring seat, and the fastener is thereafter caused to lock to the groove portion of the valve piston. The spring seat is energized by a spring to cause the fastener to lock to the step portion, whereby the spring seat is fixed to the valve piston. A clearance is disposed between the fastener and at least one of an edge portion of the groove portion on an energizing direction side and an edge portion of the step portion on the opposite side of the energizing direction.

1 - 6 . (canceled) 
   
   
       7 . A fuel supply pump comprising a fuel pressurization chamber for pressurizing fuel to a high pressure and a fuel inlet valve for supplying fuel to the fuel pressurization chamber, wherein
 the fuel inlet valve is disposed with a valve body, a valve piston that includes a collar portion on one end side and is slidably held in the valve body, a spring that energizes the valve piston in a valve closing direction, and a spring seat that is fixed in the vicinity of an end portion of the valve piston on an opposite side of the one end side and which receives one end of the spring,   the valve piston includes, in its outer surface in the vicinity of the end portion on the opposite side, a groove portion to which a fastener for fixing the valve piston and the spring seat locks,   the spring seat includes an open portion into which the valve piston is inserted and includes, along an edge of the open portion, a step portion to which the fastener locks, the valve piston is inserted into the open portion of the spring seat, the fastener is thereafter caused to lock to the groove portion of the valve piston, and the spring seat is energized by the spring to cause the fastener to lock to the step portion, whereby the spring seat is fixed to the valve piston, and   a clearance is disposed between the fastener and at least one of an edge portion of the groove portion on an energizing direction side and an edge portion of the step portion on an opposite side of the energizing direction.   
   
   
       8 . The fuel supply pump of  claim 7 , wherein the groove portion or the step portion has a cross-sectional shape of a circular are, and the clearance is disposed by offsetting a center of a circle that draws the circular arc from an outer surface position of the valve piston. 
   
   
       9 . The fuel supply pump of  claim 7 , wherein a frictional force generating member is intervened between the groove portion and the fastener or the step portion and the fastener. 
   
   
       10 . The fuel supply pump of  claim 8 , wherein a frictional force generating member is intervened between the groove portion and the fastener or the step portion and the fastener. 
   
   
       11 . The fuel supply pump of  claim 7 , wherein the fastener is a C-ring that comprises an alloy that has high elasticity. 
   
   
       12 . The fuel supply pump of  claim 7 , wherein the valve piston and the spring seat are made of carburized steel or bearing steel. 
   
   
       13 . A fuel supply pump comprising a fuel pressurization chamber for pressurizing fuel to a high pressure and a fuel inlet valve for supplying fuel to the fuel pressurization chamber, wherein
 the fuel inlet valve is disposed with a valve body, a valve piston that includes a collar portion on one end side and is slidably held in the valve body, a spring that energizes the valve piston in a valve closing direction, and a spring seat that is fixed in the vicinity of an end portion of the valve piston on an opposite side of the one end side and which receives one end of the spring,   the valve piston includes, in its outer surface in the vicinity of the end portion on the opposite side, a groove portion to which a fastener for fixing the valve piston and the spring seat locks,   the spring seat includes an open portion into which the valve piston is inserted and includes, along an edge of the open portion, a step portion to which the fastener locks, the valve piston is inserted into the open portion of the spring seat, the fastener is thereafter caused to lock to the groove portion of the valve piston, and the spring seat is energized by the spring to cause the fastener to lock to the step portion, whereby the spring seat is fixed to the valve piston, and   a contact portion between the groove portion and the fastener and a contact portion between the step portion and the fastener are connected in a diagonal direction with respect to an energizing direction.