WO2016042853A1

WO2016042853A1 - High-pressure fuel supply pump

Info

Publication number: WO2016042853A1
Application number: PCT/JP2015/066430
Authority: WO
Inventors: 眞徳渡部; 明靖宮本; 徳尾　健一郎
Original assignee: 日立オートモティブシステムズ株式会社
Priority date: 2014-09-19
Filing date: 2015-06-08
Publication date: 2016-03-24
Also published as: JP6324282B2; JP2016061246A

Abstract

The purpose of the present invention is to reduce radiation noise emitted from a damper cover, the reduction being accomplished by improving the rigidity of the damper cover to increase the natural frequency thereof. A high-pressure fuel supply pump is provided with: a reciprocating plunger; a fuel pressurizing chamber, the volume of which is changed by the reciprocation of the plunger; a suction valve located on the fuel suction side of the pressurizing chamber and opening and closing a fuel passage; a discharge valve located on the fuel discharge side of the pressurizing chamber and opening and closing a fuel passage; a pump body having the pressurizing chamber therein; a damper disposed in a damper chamber formed in the pump body; and a damper cover for covering the damper chamber. The damper cover is provided with: a substantially circular protrusion protruding either toward the side opposite the damper chamber or toward the damper chamber; and a substantially rectangular protrusion located at a position which overlaps the substantially circular protrusion and protruding to the same side as the substantially circular protrusion.

Description

High pressure fuel supply pump

The present invention relates to a high-pressure fuel supply pump used for an internal combustion engine.

As a background art in this technical field, Japanese Patent Application Laid-Open No. 2011-117429 (Patent Document 1) describes a cover portion (same as the cover of Patent Document 1) by pressing so that the central portion protrudes inward in a straight line. A high-pressure pump is described. In this high-pressure pump, the press working part forms a flow change part and a fuel collision wall inside the lid part, creates a flow of fuel toward the diaphragm that constitutes the damper, and makes the damper function sufficiently, thereby reducing the fuel pressure. The pulsation is suppressed (see paragraph 0074, FIG. 4A).

In JP 2013-64364 A (reference 2), an annular rib-shaped portion is provided at the center of the surface of the damper cover in order to further improve the rigidity of the damper cover and for other functional purposes (paragraph 0050, (See FIG. 6).

JP 2011-117429 A JP 2013-64364 A

In the high-pressure pump (high-pressure fuel supply pump) of Patent Document 1, the fuel collision wall formed in a rib shape is intended to create a flow of fuel toward the diaphragm, and has a structure in which radiation noise is considered. It is not.

Further, in the high pressure fuel supply pump of Patent Document 2, an annular rib-shaped portion is provided at the center of the surface of the damper cover to improve the rigidity of the damper cover and reduce the vibration of the damper cover. In the structure, it is difficult to suppress the vibration mode in the vertical direction of the pump, that is, the vertical direction of the damper cover. For this reason, in patent document 2, the consideration with respect to the suppression effect with respect to the radiated sound by the vibration mode of an up-down direction was not enough.

Therefore, an object of the present invention is to reduce the radiated sound radiated from the damper cover by improving the rigidity of the damper cover and increasing the natural frequency.

In order to achieve the above object, the present invention provides: "a reciprocating plunger, a fuel pressurizing chamber whose volume is changed by the reciprocating motion of the plunger, a fuel flow path located on the fuel suction side of the pressurizing chamber" A suction valve that opens and closes, a discharge valve that is located on the fuel discharge side of the pressurizing chamber and opens and closes a fuel flow path, a pump body that has the pressurizing chamber therein, and a pump body In the high-pressure fuel supply pump including a damper disposed in the damper chamber and a damper cover that covers the damper chamber, the damper cover substantially protrudes on the side opposite to the damper chamber or on the side of the damper chamber. A circular convex portion is provided, and a substantially rectangular convex portion that is convex on the same side as the substantially circular convex portion is provided at a position overlapping the substantially circular convex portion.

According to the present invention, the circular convex portion and the rectangular convex portion provided on the surface of the damper cover can improve the rigidity of the damper cover and increase the natural frequency, so that the resonance frequency due to vibration can be increased. The radiation sound radiated from can be reduced.

Issues, configurations, and effects other than those described above will be clarified by the following description of the embodiments.

It is a longitudinal section showing the whole high-pressure fuel supply pump structure of Example 1 concerning the present invention. It is a system block diagram which shows an example of the fuel supply system using the high pressure fuel supply pump of FIG. FIG. 2 is an enlarged cross-sectional view of an electromagnetically driven intake valve in the high-pressure fuel supply pump of FIG. 1, showing a state when the valve is opened (at the time of fuel intake and spill). It is the external view which looked at the high-pressure fuel supply pump of FIG. 1 from the top except for the suction joint. FIG. 5 is a cross-sectional view showing the damper cover 40 of FIG. 4 in a VV cross section.

Embodiments according to the present invention will be described below with reference to the drawings.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. 1 is a longitudinal sectional view showing the overall structure of a high-pressure fuel supply pump according to a first embodiment of the present invention. FIG. 2 is a system configuration diagram showing an example of a fuel supply system using the high-pressure fuel supply pump of FIG. FIG. 3 is an enlarged cross-sectional view showing the electromagnetically driven intake valve in the high-pressure fuel supply pump of FIG. 1, and is a view showing a state when the valve is opened (at the time of fuel intake and spilling). In addition, since the code | symbol cannot be attached | subjected to detail in FIG. 1, the code | symbol which does not have the code | symbol in FIG. 1 in description is described in the enlarged drawing mentioned later. Further, the electromagnetically driven intake valve mechanism 200 shown in FIG. 3 is shown in a state where the left and right are interchanged with respect to FIG.

The pump body (pump housing) 1 is provided with a recess 12A that forms a bottomed cylindrical space that is open at one end, and a cylinder 20 is inserted into the recess 12A from the open end side. The piston 20 is in sliding contact with the cylinder 20. As a result, the pressurizing chamber 12 is defined between the tip of the piston plunger 2, the inner wall surface of the recess 12A, and the outer peripheral surface of the cylinder 20.

A cylindrical hole 200H is formed from the peripheral wall of the pump body 1 toward the pressurizing chamber 12, and the cylindrical hole 200H has an intake valve portion INV and an electromagnetic drive mechanism portion EMD of the electromagnetically driven intake valve mechanism 200. A part of is inserted. The inside of the pump body 1 is sealed from the atmosphere. The cylindrical hole 200H sealed by attaching the electromagnetically driven intake valve mechanism 200 functions as the low pressure fuel chamber 10a.

A cylindrical hole 60 H is provided from the peripheral wall of the pump body 1 toward the pressurizing chamber 12 at a position facing the cylindrical hole 200 H across the pressurizing chamber 12. A discharge valve unit 60 is mounted in the cylindrical hole 60H. The discharge valve unit 60 has a valve seat (valve seat) 61 formed at the tip, and a valve seat member (valve seat member) 61B provided with a through hole 11A serving as a discharge passage at the center. A valve holder 62 surrounding the periphery of the valve seat 61 is fixed to the outer periphery of the valve seat member 61B. A discharge valve 63 and a spring 64 that urges the discharge valve 63 in a direction to press the discharge valve 63 against the valve seat 61 are provided in the valve holder 62. A discharge joint 11 fixed to the pump body 1 by screw fastening is provided in the opening portion on the side opposite to the pressure chamber of the cylindrical hole 60H. Thus, the discharge valve 63 is located on the fuel discharge side of the pressurizing chamber 12 and opens and closes the fuel flow path.

The electromagnetically driven suction valve mechanism 200 includes a plunger rod 201 that is electromagnetically driven. A suction valve 203 is provided at the tip of the plunger rod 201 and faces a valve seat (valve seat) 214S formed in a valve housing (valve seat member) 214 provided at an end of the electromagnetically driven suction valve mechanism 200. ing.

The other end of the plunger rod 201 is provided with a plunger rod biasing spring 202, and the suction valve 203 biases the plunger rod 201 in a direction away from the valve seat 214S. A valve stopper S 0 is fixed to the inner peripheral portion of the tip of the valve housing 214. The suction valve 203 is held between the valve seat 214S and the valve stopper S0 so as to be able to reciprocate. A valve biasing spring S4 is disposed between the suction valve 203 and the valve stopper S0, and the suction valve 203 is biased in a direction away from the valve stopper S0 by the valve biasing spring S4.

The suction valve 203 and the tip of the plunger rod 201 are biased by respective springs in opposite directions, but the plunger rod biasing spring 202 is configured by a stronger spring. The suction valve 203 is pushed in the direction away from the valve seat 214S (the right direction in the drawing) against the force of the bias spring S4, and as a result, the suction valve 203 is pushed against the valve stopper S0.

For this reason, when the electromagnetically driven intake valve mechanism 200 is OFF (when the electromagnetic coil 204 is not energized), the plunger rod 201 is connected to the intake valve 203 by the plunger rod biasing spring 202, as shown in FIGS. As shown in FIG. 3, the valve is maintained in the open position (detailed configuration will be described later). Thus, the suction valve 203 is located on the fuel suction side of the pressurizing chamber 12 and opens and closes the fuel flow path.

As shown in FIG. 2, the fuel is guided from the fuel tank 50 to the fuel inlet of the pump body 1 by the low pressure pump 51.

A plurality of injectors 54 and pressure sensors 56 are mounted on the common rail 53. The injectors 54 are mounted in accordance with the number of cylinders of the engine, and inject high-pressure fuel sent to the common rail 53 into each cylinder in response to a signal from an engine control unit (ECU) 600. A relief valve mechanism (not shown) built in the pump body 1 opens when the pressure in the common rail 53 exceeds a predetermined value, and returns excess high-pressure fuel to the upstream side of the discharge valve 60.

Referring back to FIG. A lifter and a cam (not shown) are provided at the lower end of the piston plunger 2, and the lifter is pressed against the cam by a spring 4. The piston plunger 2 is slidably held by the cylinder 20 and reciprocates by a cam rotated by an engine cam shaft or the like to change the volume in the pressurizing chamber 12. The cylinder 20 is fixed to the pump body 1 by holding the outer periphery of the lower end portion thereof with a cylinder holder 21 and fixing the cylinder holder 21 to the pump body 1.

The cylinder holder 21 is provided with a plunger seal 5 for sealing the outer periphery of the small diameter portion 2A formed on the lower end side of the piston plunger 2. The O-ring 21 C seals between the inner peripheral surface of the recess 12 A of the pump body 1 on the side opposite to the pressurizing chamber and the outer peripheral surface of the cylinder holder 21. The pump is screwed to the engine block with a flange (details are omitted) of the pump body 1 and is thereby fixed to the engine block.

Here, the damper chamber 10b and the damper cover 40 will be described. In the pump body 1, a recess 10 D that is recessed toward the cylinder 20 is formed at a position opposite to the cylinder 20 in the driving direction of the piston plunger 2. The upper opening of the recess 10D is covered with a damper cover 40, and the recess 10D and the damper cover 40 constitute a damper chamber 10b. The damper cover 40 is press-fitted and fixed to the outer peripheral surface 10F of the pump body 1.

The damper chamber 10b is formed in the middle of the fuel passage from the suction joint (not shown) to the low pressure fuel chamber 10a. The suction joint and the damper chamber 10b are connected by a fuel passage (not shown) formed in the pump body 1. A two-metal diaphragm type damper 80 is accommodated in the damper chamber 10b. The double metal diaphragm damper 80 is held by the damper holder 30 and is sandwiched between the damper cover 40 and the pump body 1. Specifically, it is sandwiched between the damper cover 40 and a step portion 10E formed inside the recess 10D. The damper holder 30 includes two members, a damper holder upper member 30A and a damper holder lower member 30B. The damper holder upper member 30A and the damper holder lower member 30B are press-fitted and fixed. The damper holder upper member 30 A and the damper holder lower member 30 B are formed with an opening at the center, and a double metal diaphragm damper 80 is held at the peripheral edge of both. The double metal diaphragm damper 80 has a pair of upper and lower metal diaphragms 80A and 80B butted together and welded around the entire circumference to seal the inside. The double metal diaphragm type damper 80 and the damper holder 30 are formed as one unit (unit).

An inert gas such as argon is sealed in the hollow portion formed by the two-plate metal diaphragms 80A and 80B, and the volume of the hollow portion changes in response to an external pressure change. Play.

A fuel passage 80U between the diaphragm 80A and the damper cover 40 is connected to a damper chamber 10b (a diaphragm 80B on one side of the two-metal diaphragm damper 80) as a fuel passage through a groove passage 80C provided on the inner peripheral wall of the damper cover 40. Is connected to the fuel passage facing. On the upper surface of the damper cover 40, a circular convex portion 40 B and a rectangular convex portion 40 A that protrude in the outer direction of the damper cover 40 are provided at the center portion. Here, the width of the rectangular convex portion 40A is set narrower than the circular convex portion 40B. Thereby, the rigidity of a damper cover can be improved.

The damper chamber 10b communicates with the low-pressure fuel chamber 10a where the electromagnetically driven suction valve 203 is located by a communication hole 10c formed in the pump body 1 constituting the bottom wall of the damper chamber 10b. Thus, the fuel sent from the feed pump 50 flows into the damper chamber 10b of the pump from the suction joint, acts on both diaphragms 80A and 80B of the double metal diaphragm damper 80, and passes through the communication hole 10c to the low pressure fuel chamber 10a. And flow.

Next, the configuration around the piston plunger 2 and the cylinder 21 will be described.

The connecting portion between the small diameter portion 2A of the piston plunger 2 and the large diameter portion 2B sliding with the cylinder 21 is connected by a conical surface 2K. A fuel sub chamber 250 is formed between the plunger seal 5 and the lower end surface of the cylinder 21 around the conical surface 2K. The fuel sub chamber 250 captures fuel leaking from the sliding surface between the cylinder 20 and the piston plunger 2. An annular passage 21G defined between the inner peripheral surface of the pump body 1, the outer peripheral surface of the cylinder 20, and the upper end surface of the cylinder holder 21 has one end at the damper chamber 10b by a vertical passage 250B formed through the pump body 1. And is connected to the fuel sub chamber 250 via a fuel passage 250 A formed in the cylinder holder 21. Thus, the damper chamber 10A and the fuel sub chamber 250 communicate with each other by the longitudinal passage 250B, the annular passage 21G, and the fuel passage 250A.

When the piston plunger 2 moves up and down (reciprocating), the tapered surface 2K reciprocates in the fuel sub chamber 250, so that the volume of the fuel sub chamber 250 changes. When the volume of the fuel sub chamber 250 increases, fuel flows from the damper chamber 10b into the fuel sub chamber 250 through the vertical passage 250B, the annular passage 21G, and the fuel passage 250A. When the volume of the fuel sub chamber 250 decreases, fuel flows from the fuel sub chamber 250 into the damper chamber 10b via the vertical passage 250B, the annular passage 21G, and the fuel passage 250A. When the piston plunger 2 rises from the bottom dead center while the suction valve 203 is maintained at the open position (the coil 204 is not energized), the fuel sucked into the pressurizing chamber is reduced in pressure from the opened suction valve 203. It overflows (spills) into the fuel chamber 10a and flows into the damper chamber 10b through the communication hole 10C. Thus, in the damper chamber 10b, the fuel from the suction joint, the fuel from the fuel sub chamber 250, the overflow fuel from the pressurizing chamber 12, and the fuel from the relief valve (not shown) are combined. As a result, the fuel pulsation of the respective fuels merges in the damper chamber 10b and is absorbed by the double metal diaphragm damper 80.

Next, the electromagnetically driven intake valve mechanism 200 will be described. Note that the electromagnetically driven intake valve mechanism 200 shown in FIG. 3 is shown in a state where the left and right sides are interchanged with respect to FIG.

In FIG. 2, the portion surrounded by a broken line indicates the pump body portion of FIG. The electromagnetically driven intake valve mechanism 200 includes a yoke 205 that also serves as the body of the electromagnetically driven mechanism EMD on the inner peripheral side of the annularly formed coil 204. In the yoke 205, a fixed core 206 and an anchor 207 are accommodated in an inner peripheral portion with a plunger rod biasing spring 202 interposed therebetween.

As shown in detail in FIG. 3, in this embodiment, the yoke 205 is divided into a side yoke 205A and an upper yoke 205B and joined by press-fitting. The fixed core 206 is divided into an outer core 206A and an inner core 206B and joined by press-fitting. The anchor 207 is fixed to the end of the plunger rod 201 opposite to the valve by welding, and faces the inner core 206B via a magnetic gap GP. The coil 204 is housed in the yoke 205, and both are fixed by screwing and fastening a screw portion provided on the outer periphery of the open end portion of the side yoke 205A to the screw portion 1SR of the pump body 1. By this fixing operation, the flange 206F formed by the open end of the side yoke 205A on the outer periphery of the outer core 206A is pushed toward the pump body 1, and the outer periphery of the open end cylindrical portion 206G of the outer core 206A is the pump. The body 1 is inserted into the inner peripheral surface of the guide hole 1GH. Further, an annular enlarged diameter portion 206GS formed as a stepped portion on the outer periphery of the open-side end tubular portion 206G of the outer core 206A is press-contacted to the annular surface portion 1GS formed around the opening side of the guide hole 1GH of the pump body 1. To do. The seal ring 206SR disposed between the annular surface portion 1GS formed around the opening side of the guide hole 1GH of the pump body 1 formed at this time and the flange portion 206F formed on the outer periphery of the outer core 206A is compressed. As a result, the space on the low pressure side including the space on the inner peripheral portion of the fixed core 206 and the low pressure fuel chamber 10a is sealed against the atmosphere.

A closed magnetic path CMP that crosses the magnetic gap GP is formed around the coil 204 by the side yoke 205A and the upper yoke 205B, the outer core 206A and the inner core 206B, and the anchor 207. The portion of the outer core 206A that faces the periphery of the magnetic gap GP is formed thin (a groove is formed when viewed from the outer periphery), and this groove portion is a magnetic diaphragm 206S (magnetic resistance) of the closed magnetic circuit CMP. Have the function of Thereby, the magnetic flux leaking through the outer core 206A can be reduced, and as a result, the magnetic flux passing through the magnetic gap GP can be increased.

Referring to FIGS. 1, 2, and 3, the operation of the high-pressure fuel supply pump of this embodiment will be described.

≪Fuel intake state≫
First, the fuel intake state will be described. In the suction process in which the piston plunger 2 descends from the top dead center position indicated by the broken line in FIG. 2 in the direction indicated by the arrow Q2, the coil 204 is in a non-energized state. The urging force SP1 of the plunger rod urging spring 202 urges the plunger rod 201 toward the suction valve 203 as indicated by an arrow. On the other hand, the urging force SP2 of the valve urging spring S4 urges the suction valve 203 in the direction indicated by the arrow. Since the urging force SP1 of the plunger rod urging spring 202 is set larger than the urging force of the urging force SP2 of the valve urging spring S4, the urging forces of both springs urge the intake valve 203 in the valve opening direction at this time. Further, the suction valve is caused by the pressure difference between the static pressure P1 of the fuel acting on the outer surface of the suction valve 203 represented by the flat portion 203F of the suction valve 203 located in the low pressure fuel chamber 10a and the pressure P12 of the fuel in the pressurizing chamber. 203 receives the force in the valve opening direction. Further, the fluid friction force P2 generated between the fuel flow flowing into the pressurizing chamber 12 along the arrow R4 through the fuel introduction passage 10P and the peripheral surface of the cylindrical portion 203H of the suction valve 203 opens the suction valve 203. Energize in the direction. Further, the dynamic pressure P3 of the fuel flow passing through the annular fuel passage 10S formed between the valve seat 214S and the annular surface portion 203R of the intake valve 203 acts on the annular surface portion 203R of the intake valve 203 to open the intake valve 203. Energize in the direction. The suction valve 203 having a weight of several milligrams is quickly opened when the piston plunger 2 starts to descend by these urging forces, and strokes until it collides with the stopper S0.

The valve seat 214 is formed on the outer side in the diameter direction than the cylindrical portion 203H of the intake valve 203 and the fuel introduction passage 10P. As a result, the area on which P1, P2, and P3 act can be increased, and the opening speed of the suction valve 203 can be increased. At this time, the plunger rod 201 and the anchor 207 are filled with the staying fuel, and the friction force with the bearing 214B acts, so that the plunger rod 201 and the anchor 207 are slightly lower than the opening speed of the suction valve 203. The stroke in the right direction of the drawing is delayed. As a result, a slight gap is formed between the distal end surface of the plunger rod 201 and the flat portion 203F of the suction valve 203. For this reason, the valve opening force provided from the plunger rod 201 falls for a moment. However, since the pressure P1 of the fuel in the low pressure fuel chamber 10a acts without delay in this gap, the suction valve 203 is opened to reduce the valve opening force applied from the plunger rod 201 (plunger rod biasing spring 202). The fluid force in the valve direction compensates. Thus, when the intake valve 203 is opened, the static pressure and dynamic pressure of the fluid act on the entire surface of the intake valve 203 on the low pressure fuel chamber 10a side, so that the valve opening speed is increased.

When the intake valve 203 is opened, the inner peripheral surface of the cylindrical portion 203H of the intake valve 203 is guided by a valve guide formed by the cylindrical surface SG of the protruding portion ST of the valve stopper S0, and the valve 203 is displaced in the radial direction. Stroke smoothly without any problems. The cylindrical surface SG forming the valve guide is formed across the upstream side and the downstream side across the surface on which the valve seat 214S is formed, and can sufficiently support the stroke of the intake valve 203. Since the dead space on the inner peripheral side can be used effectively, the dimension in the axial direction of the intake valve portion INV can be shortened. Further, since the valve urging spring S4 is installed between the end surface SH of the valve stopper S0 and the bottom surface of the flat surface portion 203F of the valve 203 on the valve stopper S0 side, the opening portion 214C and the cylindrical portion 203H of the suction valve 203 The intake valve 203 and the valve biasing spring S4 can be arranged inside the opening 214C while ensuring a sufficient passage area of the fuel introduction passage 10p formed between the two. Further, since the valve biasing spring S4 can be disposed by effectively utilizing the dead space on the inner peripheral side of the valve 203 located inside the opening 214C forming the fuel introduction passage 10p, the dimension of the intake valve portion INV in the axial direction can be arranged. Can be shortened.

The suction valve 203 has a valve guide SG at the center thereof, and has an annular protrusion 203S that contacts the receiving surface S2 of the annular surface S3 of the valve stopper S0 on the outer periphery of the valve guide SG. Further, a valve seat 214S is formed at a position on the radially outer side. On the radially outer side of the valve seat 214S and the annular surface portion 203R of the suction valve 203, three fuel passages Sn1 to Sn3 having a guide wall 1GH formed in the pump body 1 as a passage wall surface are arranged in the circumferential direction of the guide hole 1GH. It is arranged at equal intervals. Since the fuel passages Sn1 to Sn3 are formed on the radially outer side of the valve seat 214S, there is an advantage that the cross-sectional areas of the fuel passages Sn1 to Sn3 can be made sufficiently large.

Further, since the annular gap SGP is provided on the outer peripheral portion of the annular protrusion 203S, the fluid pressure P on the pressure chamber side is quickly applied to the annular gap SGP during the valve closing operation to press the suction valve 203 against the valve seat 214. The valve closing speed can be increased.

≪Fuel spill condition≫
Next, the fuel spill state will be described. The piston plunger 2 turns from the bottom dead center position and begins to rise in the direction of the arrow Q1, but since the coil 204 is in a non-energized state, a part of the fuel sucked into the pressurizing chamber 12 is partly in the fuel passages Sn1 to Sn3. Then, the fuel is spilled (overflowed) into the low-pressure fuel chamber 10a through the annular fuel passage 10S and the fuel introduction passage 10P. When the fuel flow in the fuel passages Sn1 to Sn3 switches from the direction of the arrow R4 to the direction of R5 (see FIG. 2), the fuel flow stops for a moment and the pressure in the annular gap SGP rises. Presses the suction valve 203 against the stopper S0. Rather, the suction valve 203 and the stopper S0 are connected by the fluid force that presses the suction valve 203 toward the stopper S0 by the dynamic pressure of the fuel flowing into the annular fuel passage 10S of the valve seat 214 and the suction effect of the fuel flow that flows around the outer periphery of the annular gap SGP. The suction valve 203 is firmly pressed against the stopper S0 by the fluid force acting to attract.

From the moment when the fuel flow is switched to the R5 direction, the fuel in the pressurizing chamber 12 flows into the low-pressure fuel chamber 10a in the order of the fuel passages Sn1 to Sn3, the annular fuel passage 10S, and the fuel introduction passage 10P. Here, the fuel passage cross-sectional area of the fuel passage 10S is set smaller than the fuel passage cross-sectional areas of the fuel passages Sn1 to Sn3 and the fuel introduction passage 10P. That is, the smallest fuel flow path cross-sectional area is set in the annular fuel path 10S. For this reason, pressure loss occurs in the annular fuel passage 10S and the pressure in the pressurizing chamber 12 starts to rise, but the fluid pressure P4 is received by the annular surface of the stopper S0 on the pressurizing chamber side and acts on the suction valve 203. Hard to do. Further, since the pressure equalizing hole S5 has a small hole diameter, the dynamic fluid force of the fuel on the pressurizing chamber 12 side indicated by the arrow P hardly acts on the suction valve 203.

In the spill state, fuel flows from the low pressure fuel chamber 10a to the damper chamber 10b through the four fuel through holes 214Q. On the other hand, as the piston plunger 2 rises, the volume of the auxiliary fuel chamber 250 increases, so that fuel flows through the vertical passage 250B, the annular passage 21G and the fuel passage 250A in the downward arrow direction of the arrow R8, and the fuel flows from the damper chamber 10b. Part of the fuel is introduced into the sub chamber 250. Thus, since the cold fuel is supplied to the fuel sub chamber, the sliding portion between the piston plunger 2 and the cylinder 20 is cooled.

≪Fuel discharge state≫
Next, the fuel discharge state will be described. When the coil 204 is energized based on a command from the engine control unit ECU in the fuel spill state described above, a magnetic flux flowing through the closed magnetic circuit CMP is generated as shown in FIG. When a magnetic flux flowing in the closed magnetic path CMP is generated, a magnetic attractive force MF is generated between the opposing surfaces of the inner core 206B and the anchor 207 in the magnetic gap GP. This magnetic attraction force overcomes the biasing force of the plunger rod biasing spring 202 and attracts the anchor 207 and the plunger rod 201 fixed thereto to the inner core 206B. At this time, the fuel in the storage chamber 206K of the magnetic gap GP and the plunger rod biasing spring 202 is discharged to the low pressure passage through the through hole 201H or from the fuel passage 214K to the low pressure passage through the periphery of the anchor 207. As a result, the anchor 207 and the plunger rod 201 are smoothly displaced toward the inner core 206B. When the anchor 207 contacts the inner core 206B, the anchor 207 and the plunger rod 201 stop moving.

When the plunger rod 201 is attracted to the inner core 206B, the urging force that presses the suction valve 203 toward the stopper S0 disappears, so the suction valve 203 is applied in a direction away from the stopper S0 by the urging force of the valve urging spring S4. The suction valve 203 starts to close the valve. At this time, the pressure in the annular gap SGP located on the outer peripheral side of the annular protrusion 203S becomes higher than the pressure on the low-pressure fuel 10a side as the pressure in the fuel pressurizing chamber 12 rises, and the intake valve 203 is closed. Help exercise. As a result, the intake valve 203 comes into contact with the seat 214S and closes, and the annular fuel passage 10S formed between the valve seat 214S and the annular surface portion 203R of the intake valve 203 in FIG. 3 is closed.

Thus, the annular gap SGP has an effect of assisting the valve closing movement of the suction valve 203. However, with only the valve urging spring S4, the valve closing force of the intake valve is too small, and the valve closing motion is not stable. Therefore, by providing pressure equalizing holes S5 and S6, fuel is supplied to the spring accommodating space SP through the pressure equalizing holes S5 and S6 when the suction valve 203 is closed. Thereby, the pressure in the spring housing space SP becomes constant, and the force applied when the suction valve 203 is closed is stabilized, so that the closing timing of the suction valve 203 can be stabilized. And while improving the responsiveness of both valve opening and closing, variation in valve closing timing can be further reduced.

Since the piston plunger 2 continues to rise even after the intake valve 203 is closed, the volume of the pressurizing chamber 12 decreases and the pressure in the pressurizing chamber 12 increases. As a result, as shown in FIGS. 1 and 2, the discharge valve 63 of the discharge valve unit 60 overcomes the force of the discharge valve urging spring 64 and moves away from the valve seat 61, and passes through the discharge joint 11 from the discharge passage 11A to the arrow R6. The fuel is discharged in the direction along

Thus, the annular gap SGP has an effect of assisting the valve closing movement of the suction valve 203. However, with only the valve urging spring S4, the valve closing force of the intake valve is too small, and the valve closing motion is not stable. By providing the pressure equalizing holes S5 and S6, the fuel is supplied to the spring accommodating space SP through the equalizing holes S5 and S6 when the intake valve 203 is closed, so that the pressure in the spring accommodating space SP becomes constant and the suction is performed. Since the force applied when the valve 203 is closed is stabilized, the closing timing of the suction valve 203 can be stabilized. As a result, it is possible to further improve the responsiveness of both opening and closing of the valve, and further reduce the variation in valve closing timing.

Next, the structure of the damper cover 40 will be described with reference to FIGS. FIG. 4 is an external view of the high-pressure fuel supply pump of FIG. 1 as seen from above, excluding the suction joint. FIG. 5 is a sectional view showing the damper cover 40 of FIG. 4 in a VV section.

The damper cover 40 of the present embodiment is provided with a substantially circular convex portion 40B which is convex on the opposite side of the damper chamber 10b (upper side in FIG. 1, front side in FIG. 4) on the center side. Also, the damper cover 40 is provided with a substantially rectangular convex portion 40A that is convex on the opposite side (upper side in FIG. 1, front side in FIG. 4) of the damper chamber 10b at a position overlapping the convex portion 40B. It has been. The center of the circular convex portion 40B is arranged so as to coincide with the center of the damper cover 40. The width in the short direction of the rectangular convex portion 40A is set to be narrower than the diameter of the circular convex portion 40B.

This makes it possible to increase the sectional moment of the VV section of the damper cover 40, so that the rigidity against deformation of the damper cover 40 in the vertical direction of the pump, that is, the driving direction of the piston plunger 2 can be improved. Accordingly, since the natural frequency of the damper cover 40 can be increased, resonance can be avoided by moving to a higher frequency side than the natural frequency of other pump parts and vehicle body parts, so that the sound emitted from the damper cover 40 due to resonance is reduced. it can. In addition, it is possible to further reduce noise by bringing it to a frequency band higher than the high sensitivity of human noise, or even beyond the audible range.

The damper cover 40, the circular convex portion 40B, and the rectangular convex portion 40A are configured with substantially the same plate thickness, and are created by press molding or cutting. The height of the rectangular convex portion 40A is set to be equal to or higher than the height of the circular convex portion 40B. By making the height of the rectangular convex portion 40A higher than the height of the circular convex portion 40B, the second moment of section of the VV cross section can be increased, so that the rigidity of the damper cover 40 can be increased. Can be improved.

Furthermore, in this embodiment, the electromagnetically driven suction valve mechanism 200 and the discharge valve unit 60 are arranged in a direction along the center line 100 so as to face each other with the pressurizing chamber 12 and the cylinder 20 interposed therebetween. When energization of the coil 204 is turned ON / OFF through the connector 102 (see FIG. 4), the suction valve 203 is driven in a direction along the center line 100. The intake valve 203 collides with the valve stopper S0 when the valve is opened, and collides with the valve seat 214S when the valve is closed. At this time, the collision of the suction valve 203 with the valve stopper S0 and the valve seat 214S vibrates the pump body 1, and the vibration is transmitted to the damper cover 40. In response to this vibration, the damper cover 40 generates a vibration mode in which a broken line parallel to the center line 103 orthogonal to the center line 100 is formed.

In order to reduce such vibration, in this embodiment, the longitudinal direction of the rectangular convex portion 40A is formed in the driving direction of the suction valve 203 of the electromagnetically driven suction valve mechanism 200, that is, the direction along the center line 100. Yes. As a result, the rigidity in the driving direction of the suction valve 203, that is, the direction parallel to the center line 100 is improved, so that the vibration mode can be suppressed. In the present embodiment, the rectangular convex portion 40A is parallel to the center line 100. However, as long as the direction is not perpendicular to the center line 100, the effect of reducing vibration can be achieved even if the rectangular convex portion 40A is inclined with respect to the center line 100. Is obtained.

Further, the damper cover 40 has a curved surface portion 40R formed at the outer peripheral edge portion, and both ends of the substantially rectangular convex portion 40A are connected to the curved surface portion 40R.

In addition, this invention is not limited to the above-mentioned Example, Various modifications are included. That is, the above-described embodiments have been described in detail for easy understanding of the present invention, and are not necessarily limited to those having all the configurations. Further, a part of the configuration of the embodiment can be replaced with another configuration, and another configuration can be added to the configuration of the embodiment.

For example, in the present embodiment, the substantially circular convex portion 40B and the substantially rectangular convex portion 40A are formed on the damper cover 40 so as to protrude on the opposite side of the damper chamber 10b. As long as there is no influence, the same effect can be obtained even if the substantially circular convex portion 40B and the substantially rectangular convex portion 40A are formed so as to protrude to the inside of the pump, that is, the damper chamber 10b.

Further, in this embodiment, one circular convex portion 40B and one rectangular convex portion 40A are provided, but it is not always necessary to have one, and there may be one or more. In that case, the heights of the circular convex portion 40A and the rectangular convex portion 40A do not have to be the same, and may be different heights. For example, two rectangular shapes intersecting at a 90-degree cross shape with one circular convex portion 40A and a shape having two circular convex portions 40B having different diameters or one circular convex portion 40B. A shape provided with the convex portion 40A is also possible. In the case of having a plurality of rectangular convex portions 40A, there is no limitation on the angle at which they intersect with each other, and one rectangular formed in the driving direction of the intake valve 203 of the electromagnetically driven intake valve mechanism 200, that is, in the direction along the center line 100. The angle may be any angle with respect to the shape convex portion 40A.

Further, in the circular convex portion 40B and the rectangular convex portion 40A, it is possible to use both the shape projecting outside the pump and the shape projecting inward. Further, the circular convex portion 40B may be substantially circular, for example, an ellipse. Furthermore, the rectangular convex portion 40A may be substantially rectangular, and may be, for example, a rectangle, a square, a rhombus, or the like.

In order to reduce the radiated sound from the damper cover 40, the rigidity of the surface of the damper cover 40 is increased to increase the secondary moment, and the area of the flat surface where the radiated sound is likely to be emitted is reduced. Therefore, the shape, number, combination, and the like of the circular convex portion 40A and the rectangular convex portion can be changed as necessary.

DESCRIPTION OF SYMBOLS 10b ... Damper chamber, 10P ... Bending passage part, 10S ... Gap passage part, 11 ... Discharge joint, 12 ... Pressurization chamber, 30 ... Damper holder, 40 ... Damper cover, 40A ... Rectangular protrusion, 40B ... Circular convex part 40R ... R section, 60 ... discharge valve unit, 61 ... valve seat, 61B ... valve seat member, 61B ... valve seat member, 63 ... discharge valve, 80C ... groove passage, 80U ... fuel passage, 200 ... electromagnetically driven suction Valve mechanism 203 ... Suction valve 214 ... Valve housing 214S ... Valve seat

Claims

A reciprocating plunger;
A fuel pressurizing chamber whose volume is changed by the reciprocating motion of the plunger;
An intake valve located on the fuel intake side of the pressurizing chamber, for opening and closing the fuel flow path;
A discharge valve located on the fuel discharge side of the pressurizing chamber for opening and closing the fuel flow path;
A pump body having the pressurizing chamber therein;
A damper disposed in a damper chamber formed in the pump body;
In a high pressure fuel supply pump comprising a damper cover that covers the damper chamber,
The damper cover is provided with a substantially circular convex portion that is convex on the opposite side of the damper chamber or on the damper chamber side, and the substantially circular convex portion at a position overlapping the substantially circular convex portion. A high-pressure fuel supply pump, characterized in that a substantially rectangular convex portion that is convex on the same side is provided.
The high-pressure fuel supply pump according to claim 1,
The width of the substantially rectangular convex part in the short direction is set to be narrower than the diameter of the substantially circular convex part.
The high-pressure fuel supply pump according to claim 1,
The high-pressure fuel supply pump according to claim 1, wherein the substantially rectangular convex portion is formed along a direction other than a direction perpendicular to a driving direction of the intake valve.
The high-pressure fuel supply pump according to any one of claims 1 to 3,
The high-pressure fuel supply pump is characterized in that the damper cover has a curved surface portion at an outer peripheral edge portion, and both end portions of the substantially rectangular convex portion are connected to the curved surface portion.
The high-pressure fuel supply pump according to claim 1,
The high-pressure fuel supply pump according to claim 1, wherein a height of the substantially circular convex portion is equal to or higher than a height of the substantially rectangular convex portion.
The high-pressure fuel supply pump according to any one of claims 1 to 3,
The high-pressure fuel supply pump, wherein the damper cover, the substantially circular convex portion, and the substantially rectangular convex portion are formed with substantially the same thickness.