JP6354530B2 - High pressure fuel pump - Google Patents

Description

  The present invention relates to a high-pressure fuel pump that pressurizes and discharges fuel sucked into a pressurizing chamber by reciprocating movement of a plunger.

Conventionally, as a high-pressure fuel pump for supplying high-pressure fuel to an internal combustion engine, a supply pump that pressurizes and discharges fuel sucked into a pressurizing chamber from a fuel gallery through an electromagnetic valve (for example, Patent Document 1 and Patent Document 1). 2).
A structure of a plunger pump generally employed as such a supply pump is shown in FIGS.
The supply pump includes a plunger 101, a cylinder body 102, and a solenoid valve. The cylinder body 102 is provided with a cylindrical electromagnetic valve fastening portion 103 to which the electromagnetic valve is connected by screw fastening or the like.

In the supply pump, a disc-shaped stopper member 107 that restricts the movement range of the valve 106 of the solenoid valve is disposed between the cylinder 104 of the cylinder body 102 and the valve body 105 of the solenoid valve. The stopper member 107 functions as a cover member that closes the opening end of the cylinder 104 and forms the pressurizing chamber 108 between the stopper member 107 and the plunger 101. The stopper member 107 is formed with a plurality of communication holes 115 and through holes 119 extending in the plate thickness direction.
Here, as shown in FIG. 13, the supply pump is formed with an inclined groove 113 having a minute wedge-shaped cross section whose groove width becomes narrower toward the outside in the radial direction. The inclined groove 113 is provided radially inward from a boundary portion a formed between the first seal surface 111 of the cylinder body 102 and the second seal surface 112 of the stopper member 107.

By the way, in the supply pump, when the moving direction of the plunger 101 is the fuel suction direction, there is a concern that the fuel containing bubbles flows into the pressurizing chamber 108 from the fuel gallery through the fuel suction path.
Here, when the plunger 101 moves in the fuel pressurizing direction, the fuel containing bubbles sucked into the pressurizing chamber 108 is radially outside the pressurizing chamber 108 along the lower surface 114 of the stopper member 107. It flows toward. The fuel traveling outward in the radial direction reaches the opening side of the inclined groove 113 and enters the inclined groove 113 along the inclined groove wall surface (lower surface 114) provided on the same plane as the second seal surface 112. As shown in FIGS. 12 and 13, the fuel that has entered the inclined groove 113 is the back side of the inclined groove 113, that is, the boundary portion formed between the first seal surface 111 and the second seal surface 112. Reach a. Thereby, the bubbles contained in the fuel concentrate on the back side of the inclined groove 113, that is, the boundary portion a.
When the bubbles collapse, cavitation erosion (erosion) occurs at the boundary portion a (the first seal surface 111 or the second seal surface 112). When this erosion progresses, the fuel in the pressurizing chamber 108 flows out to the fuel gallery side even if the electromagnetic valve is closed.
As a result, the supply pump cannot pressurize the fuel, cannot supply the fuel into the cylinder of the engine, and causes a problem of inducing an engine stall.

By the way, Patent Document 2 shows a fuel injection pump having a structure in which a seal member is interposed between a cylinder member and the stopper without the stopper directly contacting the mounting surface of the cylinder member.
However, the lower surface of the stopper is provided on the same plane as the sheet surface of the stopper, and is provided continuously with no step between the sheet surface of the stopper.
Therefore, there is a fuel flow outward in the radial direction toward the boundary portion along the lower surface of the stopper. As a result, even in a high-pressure fuel pump having a structure in which the seal member is sandwiched between the cylinder member and the stopper, it is considered that erosion occurs at the boundary portion.

JP 2006-170169 A Japanese Patent Laid-Open No. 03-219178

  An object of the present invention is to provide a high-pressure fuel pump capable of preventing the occurrence of cavitation erosion at a boundary portion between a first seal surface of a cylinder member and a second seal surface of a cover member.

According to the present invention (high pressure fuel pump), the cover member includes a first seal surface of the cylinder member and the cover member in the fuel flow in the pressurizing chamber when the plunger moves in the fuel pressurizing direction. A flow inhibition portion is provided that inhibits the fuel flow outward in the radial direction toward the boundary portion formed between the second seal surface and the second seal surface.
Here, the first aspect of the flow blocking portion is a groove that is recessed in the direction of movement of the plunger relative to the second seal surface, and the groove is a recess that is connected to the second seal surface via a predetermined step. It has a groove bottom. The cover member is made of a single metal plate, and the bottom surface of the groove is provided on the metal plate. Moreover, the 2nd aspect of a flow inhibition part is the protrusion wall which protruded in the moving direction of the plunger rather than the 2nd seal surface, and a protrusion wall is a protrusion end surface connected through a predetermined level | step difference with a 2nd seal surface. have.
Thereby, the fuel flow to the outer side in the radial direction toward the boundary between the first seal surface and the second seal surface in the fuel flow to the outer side in the radial direction in the pressurizing chamber is prevented. For this reason, for example, when the movement direction of the plunger is the fuel suction direction, even if the fuel containing bubbles flows into the pressurized chamber, the bubbles contained in the fuel are separated from the boundary between the first seal surface and the second seal surface. It becomes difficult to concentrate on the part.

Therefore, since the occurrence of cavitation erosion at the boundary portion can be reduced, it is possible to prevent the fuel in the pressurized chamber from leaking out. Thereby, when the moving direction of the plunger is, for example, the fuel pressurizing direction, the fuel sucked into the pressurizing chamber can be pressurized and discharged.
As a result, for example, high-pressure fuel can be supplied to the internal combustion engine, so that engine stall can be prevented from being induced.
The cover member is provided with a plunger-side end surface (for example, a groove bottom surface of a concave portion or a protruding end surface of a convex portion) that closes the opening end of the cylinder to form a pressure chamber between the cover member. That is, the above-mentioned flow blocking portion is a structure (for example, a concave portion or a convex portion) in which the boundary portion between the first seal surface and the second seal surface and the plunger side end surface are not provided on the same plane. .

It is sectional drawing which showed the supply pump (Example 1). (A), (b) is sectional drawing and the top view which showed the stopper periphery structure of the solenoid valve (Example 1). (A) is III (a) -III (a) sectional drawing of (b), (b) is explanatory drawing which showed the fuel flow in a pressurized chamber (Example 1). (A), (b) is sectional drawing and the top view which showed the stopper periphery structure of the solenoid valve (Example 2). (A) is V (a) -V (a) sectional drawing of (b), (b) is explanatory drawing which showed the fuel flow in a pressurized chamber (Example 2). (A), (b) is sectional drawing and the top view which showed the stopper periphery structure of a solenoid valve (Example 3). (A) is VII (a) -VII (a) sectional drawing of (b), (b) is explanatory drawing which showed the fuel flow in a pressurization chamber (Example 3). (Example 4) which is sectional drawing which showed the supply pump. (Example 4) which is sectional drawing which showed the valve body periphery structure of an intake valve. It is sectional drawing which showed the supply pump (conventional example). (A) is XI (a) -XI (a) sectional drawing of (b), (b) is explanatory drawing which showed the stopper periphery structure of a solenoid valve (conventional example). It is XII-XII sectional drawing of FIG.11 (b) (conventional example). It is XIII-XIII sectional drawing of FIG. 14 (conventional example). It is explanatory drawing which showed the fuel flow and cavitational erosion in a pressurized chamber (conventional example).

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[Configuration of Example 1]
1 to 3 show a supply pump (Example 1) to which the high-pressure fuel pump of the present invention is applied.

The liquefied gas fuel supply device (hereinafter referred to as fuel supply system) of the present embodiment is constituted by a common rail fuel injection system (accumulated fuel injection device) known as a fuel injection system for an internal combustion engine (hereinafter referred to as engine) such as a diesel engine. Has been.
The common rail fuel injection system includes a fuel filter, a low pressure fuel pump (hereinafter referred to as a feed pump), a high pressure fuel pump (hereinafter referred to as a supply pump), a common rail, and a plurality of injectors.

The supply pump includes a camshaft 1 that rotates in synchronization with the rotation of the crankshaft of the engine, and a pump housing 2 that rotatably supports the camshaft 1. This supply pump includes a plunger 3 that can reciprocate and a cylinder member (hereinafter referred to as a cylinder body) 4 that supports the plunger 3 so as to be capable of reciprocating sliding.
The supply pump is disposed on one side (the upper side in the drawing) of the cylinder body 4 in the axial direction with respect to the cylinder 5 and opens and closes a fuel intake passage (described later) upstream of the pressurizing chamber 6. An electromagnetic valve having a spool valve 7 is provided.

The electromagnetic valve includes a valve body 8 that supports the spool valve 7 so as to be slidable back and forth, and a stopper member 9 that regulates the movement range of the spool valve 7. The solenoid valve is fastened and fixed to a solenoid valve fastening portion (hereinafter, fastening portion) 10.
The pump housing 2 defines an annular fuel gallery 11 that supplies fuel to the pressurizing chamber 6 through a fuel intake passage between the outer peripheral surface of the cylinder body 4. Fuel is introduced into the fuel gallery 11 from a feed pump via an inlet port (not shown: hereinafter, suction port) of a supply pump.

Here, the supply pump is a plunger that pressurizes and discharges the fuel sucked into the pressurizing chamber 6 from the fuel gallery 11 through the fuel suction passage when the plunger 3 reciprocates in the cylinder 5 of the cylinder body 4. It is a pump.
The pump housing 2 is formed with a cylindrical fastening portion (joint portion) to which the overflow valve 12 is connected by screw fastening or the like. The fastening portion is provided with a female screw hole (overflow port) that opens toward the outside.
The plunger 3 is fitted and arranged in the cylinder 4 so as to be able to reciprocate. The plunger 3 forms a pressurizing chamber 6 between which the fuel is pressurized by movement of the plunger 3 in the fuel pressurizing direction between the lower end surface (plunger side end surface) of the stopper member 9 of the electromagnetic valve. .

The cylinder body 4 is formed with a cylindrical fastening portion 10 to which an electromagnetic valve is connected by screw fastening or the like. The fastening portion 10 is provided with a female screw hole (accommodating recess) that opens toward the outside.
The cylinder body 4 is formed with a cylindrical fastening portion (joint portion) to which the pipe joint 13 is connected by screw fastening or the like. The fastening portion is provided with a female screw hole (accommodating recess) that opens outward. A discharge valve having a check valve structure having a valve body (valve) 14 for opening and closing a fuel discharge passage (described later) downstream of the pressurizing chamber 6 on the back side (pressurizing chamber side) of the housing recess. Is housed.
Here, the fuel pressurized by the internal volume of the pressurizing chamber 6 expanding and contracting with the reciprocating movement of the plunger 3 is pressure-fed and supplied from the pressurizing chamber 6 to the common rail via the discharge valve.

The camshaft 1 is rotatably supported by the pump housing 2. A cam 15 having a plurality of (at least one) cam ridges is integrally assembled on the outer periphery of the camshaft 1.
The pump housing 2 is provided with an overflow valve 12 that opens when the fuel pressure in the fuel gallery 11 rises above a predetermined pressure. Inside the pump housing 2 is disposed a tappet 16 that reciprocates (moves up and down) in the vertical direction in the figure. The illustrated lower end of the plunger 3 is in contact with the illustrated upper end surface of the tappet 16. A cam roller 17 is disposed at the lower portion of the tappet 16 in the figure.
As a result, when the cam 15 is rotated by the rotation of the camshaft 1, the tappet 16 is reciprocated (vertically moved) in the vertical direction in the drawing via the cam roller 17. Such movement of the tappet 16 is transmitted to the plunger 3, and the plunger 3 reciprocates (vertically moves) in the vertical direction in the figure in the cylinder 5.

A cylinder body 4 is fastened and fixed to the pump housing 2 with bolts or the like. A cylindrical cylinder 5 in which the sliding surface of the plunger 3 can slide back and forth is formed inside the cylinder body 4. A pressure chamber 6 is formed on one end side of the cylinder 5 in the axial direction (outside in the radial direction of the camshaft 1).
A lower spring seat is assembled to the outer periphery of the lower end of the plunger 3 in the figure. In addition, an upper spring seat is disposed on the outer periphery of the intermediate portion of the pump housing 2 or the lower end of the cylinder body 4 in the figure so as to face the lower spring seat.
A plunger spring 19 is installed between the upper and lower spring seats to urge the tappet 16 and the cam roller 17 in the direction of pressing the outer peripheral surface (profile) of the cam 15.

The fuel suction channel includes a fuel suction hole 21 communicating with the fuel gallery 11, an annular fuel suction channel 22 communicating with the fuel suction hole 21, a fuel suction hole 23 communicating with the fuel suction channel 22, and the fuel suction channel. A fuel flow path (clearance) 24 that communicates with the hole 23, a valve body accommodating chamber (valve accommodating chamber) 25 that communicates with the clearance 24, and the like.
The fuel discharge passage has a fuel discharge hole 31 communicating with the pressurizing chamber 6, fuel discharge holes 32-35 communicating with the fuel discharge hole 31, an outlet port (discharge port) 36 opened to the outside, and the like. doing.

The cylinder body 4 is provided with a discharge valve having a check valve structure and a piping joint 13.
The discharge valve is sandwiched between the bottom of the housing recess of the cylinder body 4 and the pipe joint 13. This discharge valve presses the valve 14 that opens and closes the fuel discharge hole 32, a cylindrical valve body 37 that supports the valve 14 so as to reciprocate, and the valve seat surface (valve seat) of the valve body 37. A coil spring 38 or the like that is biased to the side is provided. A fuel discharge hole 32 that communicates with the pressurizing chamber 6 through the fuel discharge hole 31 is formed inside the valve body 37.

The pipe joint 13 is connected to a common rail pipe joint via a fuel pipe. A coil spring 38 and a spring seat 39 are accommodated inside the pipe joint 13. Further, inside the pipe joint 13, a fuel discharge hole 33 that communicates with the fuel discharge hole 32, a fuel discharge hole 35 that communicates with the fuel discharge hole 33 via the fuel discharge hole 34, and a communication with the fuel discharge hole 35. A discharge port 36 is formed.
A fuel discharge hole 34 that connects the fuel discharge hole 33 and the fuel discharge hole 35 is formed in the spring seat 39.
Here, the high-pressure fuel pressurized as the internal volume of the pressurizing chamber 6 expands and contracts as the plurality of plungers 3 reciprocate is pumped from the discharge port 36 to the common rail via the fuel pipe.
Details of the cylinder body 4 will be described later.

The electromagnetic valve constitutes a normally open type (normally open type) electromagnetic flow control valve that controls the amount of fuel discharged from the discharge port 36 of the supply pump to the common rail. The electromagnetic valve includes a spool valve 7 that reciprocates in the axial direction, and a valve body 8 that accommodates the spool valve 7 so as to be slidable back and forth.
The spool valve 7 is a valve body of a solenoid valve, and is a fuel suction passage (fuel suction hole 21 → fuel suction passage 22 → fuel suction hole 23 → clearance 24 → communication between the fuel gallery 11 and the pressurizing chamber 6). The fuel intake path (up to the valve housing chamber 25) is opened and closed.

A conical surface (tapered) valve seat (hereinafter referred to as a valve seat surface) 41 that restricts the valve lift amount of the solenoid valve (particularly the valve fully closed position of the spool valve 7) is provided on the lower end surface of the valve body 8 in the figure. Yes. A valve portion (large diameter portion) 42 of the spool valve 7 is seated on the valve seat surface 41.
Inside the valve body 8, a fuel suction hole 23, a clearance 24 and a valve storage chamber 25 are formed. Further, an axial hole 43 that supports the spool valve 7 so as to be slidable back and forth is formed on the central axis of the valve body 8.

The fuel suction hole 23 is provided outside the axial hole 43 in the radial direction, and intersects the axial hole 43 in a cross shape. The fuel suction hole 23 communicates with a fuel suction flow path 22 provided so as to surround the valve body 8 and the stopper member 9 in the circumferential direction.
The clearance 24 is a fuel intake passage formed between the valve seat surface 41 of the valve body 8 and the outer periphery of the valve portion 42 of the spool valve 7 when the electromagnetic valve is opened.
The valve storage chamber 25 is provided with a diameter larger than the diameter of the axial hole 43. The valve housing chamber 25 is a valve body housing chamber and houses the valve portion 42 of the spool valve 7 so as to be capable of reciprocating.

The solenoid valve adjusts the fuel suction period from the fuel gallery 11 through the fuel suction passages (21 to 25) and the communication hole 45 into the pressurizing chamber 6, thereby discharging the fuel discharged from the discharge port 36 of the supply pump. An electromagnetic pump discharge amount control valve (PCV) for controlling the discharge amount.
The valve lift amount of the solenoid valve (in particular, the valve fully open position of each spool valve 7) is regulated by a valve stopper surface 44 formed on the upper end surface of the stopper member 9 in the figure. A plurality of communication holes 45 and one through hole 46 are formed in the stopper member 9.
Details of the stopper member 9 will be described later.

The electromagnetic valve includes an electromagnetic actuator (solenoid) that drives the spool valve 7 in the valve closing direction.
The solenoid is accommodated together with the upper end side of the valve body 8 in the cylindrical housing 47 connected to the upper end side of the valve body 8. This solenoid includes an external connection connector and is configured to be energized and controlled by a pump drive current applied from an engine control unit (electronic control unit: ECU).

The solenoid includes a coil wound around the outer periphery of the bobbin, a coil inner peripheral fixed core disposed on the inner peripheral side of the coil, a coil outer peripheral fixed core disposed on the outer peripheral side of the coil, and a coil inner peripheral fixed. An armature that reciprocates in the core is provided.
When supplied with electric power (applied to voltage or energized), the coil generates a magnetic force that attracts the armature to the magnetic pole surface of the coil inner peripheral fixed core.
A coil spring (not shown) that biases the armature in the valve opening direction of the spool valve 7 is attached to the inside of the housing 47. On the outer periphery of the housing 47, a male screw that is screwed into a female screw hole formed on the inner periphery of the fastening portion 10 is provided. Further, on the outer periphery of the housing 47, there is provided a polygonal tool engaging portion used when connecting (connecting) the electromagnetic valve to the fastening portion 10 (fastening operation).

Next, details of the cylinder body 4, the cylinder 5, and the stopper member 9 of the present embodiment will be briefly described with reference to FIGS.
The cylinder body 4 has a cylindrical cylinder 5 and an annular first seal surface 51, and supports the plunger 3 so as to be slidable back and forth. The cylinder body 4 is provided with a cylindrical fastening portion 10 that houses an electromagnetic valve therein. On the inner periphery of the fastening portion 10, a female screw hole that is screwed with a male screw formed on the outer periphery of the electromagnetic valve is provided.
In addition, the cylinder body 4 includes an annular inclined surface having a chamfered inner peripheral corner portion on the opening side of the cylinder 5.

The cylinder 5 is open at both ends in the axial direction, and the plunger 3 is fitted and arranged. The cylinder 5 is open at the center of the bottom (annular step) of the housing recess formed in the fastening portion 10. The housing recess opens toward the outside on one side in the axial direction. The accommodating recesses are provided on the same axis as the cylinder 5 and are hermetically (liquid-tight) closed by the valve body 8 of the electromagnetic valve, the housing 47, and the like.
The first seal surface 51 is a flat open end surface extending radially outward from the open end on one side of the cylinder 5 in the radially outward direction. The first seal surface 51 is attached with the outer peripheral edge (hereinafter referred to as a flange) 52 of the stopper member 9 in close contact.

The stopper member 9 corresponds to a “cover member” in the claims. The stopper member 9 includes a cover 53 that closes the opening end of the cylinder 5 and forms the pressurizing chamber 6 with the plunger 3 on the inner peripheral side of the flange 52.
A communication hole 45 and a through hole 46 are formed in the cover 53.
A plurality of communication holes 45 (eight in this example) are provided on the same circumference of the cover 53 at predetermined intervals (for example, equal intervals). These communication holes 45 are flow path holes that allow the valve housing chamber 25 and the pressurizing chamber 6 to communicate with each other. The plurality of communication holes 45 are formed through the cover 53 in the plate thickness direction so as to communicate with both end surfaces (upper end surface 55 and lower end surface 56) of the cover 53 in the plate thickness direction. Further, the inlet openings of the plurality of communication holes 45 are opened at the upper end surface 55 of the stopper member 9. The through hole 46 is formed through the center of the cover 53 in the thickness direction of the cover 53. The through hole 46 is provided to prevent the valve portion 42 of the spool valve 7 from adsorbing to the valve stopper surface 44. One end side opening of the through hole 46 is opened at the valve stopper surface 44 of the stopper member 9. Further, the other end side opening of the through hole 46 is opened at the lower end surface 56 of the stopper member 9.

An annular flange 52 is provided around the cover 53. An annular second sealing surface 57 that seals the pressurizing chamber 6 in close contact with the first sealing surface 51 of the cylinder body 4 is provided on the lower end surface of the flange 52 in the figure. The second seal surface 57 is a flat opposed end surface extending in the radial direction orthogonal to the moving direction of the plunger 3. As a result, fuel leakage from the pressurizing chamber 6 to the fuel intake passage 22 can be prevented when the solenoid valve is closed.
An annular fourth seal surface 59 is provided on the upper end surface of the flange 52 in the drawing to seal the valve body 8 in close contact with the third seal surface 58. The fourth seal surface 59 is a flat opposed end surface extending in the radial direction orthogonal to the moving direction of the plunger 3. Thereby, the fuel leakage from the valve storage chamber 25 to the fuel intake passage 22 can be prevented when the electromagnetic valve is closed.

By the way, the supply pump has an inner diameter surface of the cylinder 5 and a first seal surface 51 for the purpose of improving the slidability of the plunger 3 with respect to the cylinder 5 and the sealability of the first seal surface 51 with respect to the second seal surface 57. It is ground using a grinding tool.
For this reason, a burr | flash may remain in the internal peripheral corner | angular part where the internal-diameter surface of the cylinder 5 and the 1st seal surface 51 cross | intersect perpendicularly.
If a burr enters between the first seal surface 51 and the second seal surface 57, there is a problem that the high-pressure sealability between the first seal surface 51 and the second seal surface 57 is reduced. To do.

Therefore, in the supply pump, burrs generated at the inner peripheral corner on the opening side of the cylinder 5 are generally removed by chamfering.
Thereby, as shown in FIG. 13, the inclined groove 61 is formed radially inward from the boundary portion a formed between the first seal surface 51 and the second seal surface 57.
The inclined groove 61 opens at the inner diameter surface of the cylinder 5 and has a cross-sectional minute wedge shape in which the groove width becomes narrower from the opening side toward the radially outer side.
Further, the flange 52 has an annular inclined groove wall surface that forms an annular inclined groove 61 between the inclined surface of the cylinder 5.
The inclined surface of the cylinder 5 is a chamfered portion where a corner portion where the second seal surface 57 and the inner surface of the cylinder 5 (hereinafter referred to as a cylinder inner surface) intersect perpendicularly is chamfered. The chamfered portion is constituted by a conical surface inclined with respect to the second seal surface 57 and the cylinder inner diameter surface.

Here, the cover 53 is provided with an annular groove 62 that is recessed in the movement direction of the plunger 3 (fuel pressurization direction) from the lower end surface 56 and the second seal surface 57 of the stopper member 9. The recessed groove 62 is provided so as to surround the periphery of the central protruding wall 63 having the circular lower end surface 56 in the circumferential direction.
The concave groove 62 corresponds to a “flow inhibiting portion” in the claims. Thereby, the boundary part a formed between the first seal surface 51 and the second seal surface 57 in the fuel flow in the pressurizing chamber 6 in the direction in which the plunger 3 moves is the fuel pressurization direction, that is, The fuel flow to the outer side in the radial direction toward the inner side of the inclined groove 61 is hindered.

The concave groove 62 has a groove width slightly larger than the outlet diameter of the plurality of communication holes 45. The concave groove 62 has an annular concave groove bottom surface 64 connected to the lower end surface 56 and the second seal surface 57 via a predetermined cylindrical step. The concave groove bottom surface 64 is not provided on the same plane as the lower end surface 56 and the second seal surface 57. The outlet openings of the plurality of communication holes 45 are open at the groove bottom face 64.
The concave groove bottom surface 64 of the concave groove 62 constitutes an annular plunger side end surface that closes the opening end of the cylinder 5 and forms the pressurizing chamber 6 with the plunger 3.

On the outer peripheral side of the concave groove 62, a cylindrical inner wall 65 is provided so as to extend in the circumferential direction of the stopper member 9, which inhibits the fuel flow radially outward toward the inner side of the inclined groove 61. . The inner wall 65 is provided on the outer peripheral side of the recessed groove 62, constitutes a cylindrical step, and has an inner diameter that is substantially the same as the inner diameter of the cylinder 5.
A cylindrical peripheral wall 66 extending in the circumferential direction of the stopper member 9 is provided on the inner peripheral side of the concave groove 62. The peripheral wall 66 is provided on the inner peripheral side of the concave groove 62, and a concave groove bottom surface 64 is formed between the peripheral wall 66 and the inner wall 65.
A central projecting wall 63 projecting in the moving direction of the plunger 3 (fuel intake direction) from the concave groove bottom surface 64 is provided on the inner peripheral side of the inner wall 65. The hole opening of the through hole 46 opens at the lower end surface 56 of the central protruding wall 63.
The concave groove bottom surface 64, the inner wall 65, and the peripheral wall 69 constitute a flow allowing portion that allows fuel flow to both sides in the circumferential direction toward one communication hole 45 among the plurality of communication holes 45.

[Operation of Example 1]
Next, the operation of the supply pump of this embodiment will be briefly described with reference to FIGS. When the camshaft 1 of the supply pump is rotationally driven by the crankshaft of the engine, the plunger 3 reciprocates in the moving direction in the cylinder 5 of the cylinder body 4.
At this time, the fuel discharged from the feed pump is supplied into the fuel gallery 11 from the suction port of the supply pump.

Here, when the movement direction of the plunger 3 is the fuel suction direction, the fuel is sucked into the fuel suction hole 21 from the fuel gallery 11 when the solenoid valve is opened.
Then, the fuel sucked into the fuel suction hole 21 is sucked into the pressurizing chamber 6 through the fuel suction flow path 22 → the fuel suction hole 23 → the clearance 24 → the valve housing chamber 25 → the plurality of communication holes 45.
When the plunger 3 reaches the bottom dead center and the moving direction of the plunger 3 is reversed in the fuel pressurizing direction, the fuel pressure in the pressurizing chamber 6 is increased when the electromagnetic valve is closed at a predetermined timing.
When the plunger 3 further moves in the fuel pressurizing direction and the fuel pressure in the pressurizing chamber 6 rises above the valve opening pressure of the discharge valve, the discharge valve opens and the fuel discharge hole from the pressurizing chamber 6 opens. High pressure fuel is fed to the common rail via the discharge ports 36 through 31 to 35.
The high-pressure fuel accumulated in the common rail is injected and supplied into each cylinder of the engine at a predetermined timing by opening and driving a plurality of injectors at an arbitrary injection timing.

By the way, during the pumping stroke in which the fuel is discharged from the pressurizing chamber 6 of the supply pump, the solenoid valve is closed until the solenoid valve is closed and the pumping starts, that is, the solenoid valve is opened. In the meantime, the fuel in the pressurizing chamber 6 is returned to the fuel gallery 11 through the fuel suction passages (21 to 25). This process is called pre-stroke.
The fuel discharge to the fuel gallery 11 is stopped when the solenoid valve is closed, and the fuel discharge amount (pump discharge amount or pump pumping amount) is defined by the fuel amount remaining in the pressurizing chamber 6 at this time. The
It should be noted that the pump discharge amount increases as the solenoid valve closing timing, which is the pumping start timing, is advanced to the bottom dead center side of the plunger 3 and the pump pumping period is lengthened. Further, the maximum pump discharge amount is obtained when the closing timing of the solenoid valve is substantially the bottom dead center of the plunger 3 (total pressure feeding).

Further, during a period from the top dead center to the bottom dead center, the plurality of plungers 3 suck fuel into the pressurizing chamber 6 from the plurality of fuel gallery 11 through the fuel suction passages (21 to 25) and the communication hole 45. Inhalation period (pump inhalation period).
In addition, a period from the bottom dead center to the top dead center of the plurality of plungers 3 is a fuel pumping period (pump) in which fuel is pumped from the plurality of pressurizing chambers 6 to the common rail side through the fuel discharge passages (31 to 36). (Pumping period).
Needless to say, the pumping period varies depending on the closing timing of the plurality of solenoid valves.

[Features of Example 1]
As described above, in the supply pump of this embodiment, the stopper member 9 is connected to the cylinder body 4 by the screw fastening axial force generated when the electromagnetic valve is coupled (connected) to the fastening portion 10 of the cylinder body 4 by screw fastening. The first seal surface 51 and the third seal surface 58 of the valve body 8 are held and fixed.
Accordingly, the stopper member 9 has a function of high-pressure sealing between the first seal surface 51 of the cylinder body 4 and the second seal surface 57 of the stopper member 9, and the third seal surface 58 of the valve body 8 and the stopper member. 9 and the fourth sealing surface 59 are provided with a function of high-pressure sealing.

Further, the valve stopper surface 44 of the stopper member 9 has a function of defining the full lift amount (valve opening position) of the spool valve 7 of the electromagnetic valve.
Further, each communication hole 45 of the stopper member 9 has a function as a flow path through which fuel flows from the fuel gallery 11 into the pressurizing chamber 6 during the suction stroke of the supply pump.
Each communication hole 45 of the stopper member 9 has a function as a flow path for returning the fuel that has flowed into the pressurizing chamber 6 to the fuel gallery 11 through the fuel intake flow path during the pre-stroke period.

Here, during the pre-stroke period, the typical fuel flow in the pressurizing chamber 108 of the conventional supply pump is the fuel flow shown in FIGS.
In the fuel flow in the pressurizing chamber 108, the fuel flow mainly toward one side (the upper side in the drawing) in the axial direction toward each communication hole 115 of the stopper member 107 is as shown in FIG. After passing through the communication hole 115, the fuel flows into the fuel gallery through the valve housing chamber 116 → the fuel suction hole 117 → the fuel suction passage 118.
On the other hand, in the fuel flow in the pressurizing chamber 108, the fuel flow mainly radially outward along the lower surface 114 of the stopper member 107 is the cylinder inner surface along the lower surface 114 as shown in FIG. To reach.

By the way, when the fuel does not normally flow from the fuel tank to the supply pump due to the clogging of the fuel filter or the like, the pressure of the fuel gallery is lowered to generate bubbles. After the fuel containing the bubbles flows into the pressurizing chamber 108, the bubbles reach the cylinder inner surface along the lower surface 114 of the stopper member 107 together with the fuel and enter the inclined groove 113 in the prestroke stroke.
The fuel containing bubbles that have entered the inclined groove 113 concentrates on the inner side of the inclined groove 113, that is, the boundary portion a formed between the first seal surface 111 and the second seal surface 112.
When the bubbles collapse, cavitation erosion (erosion) occurs at the boundary portion a (indicated by a two-dot chain line in FIG. 11). When this erosion progresses, the fuel in the pressurizing chamber 108 flows out to the fuel gallery side even when the solenoid valve is closed.
As a result, the supply pump cannot pressurize the fuel, cannot supply the fuel into the cylinder of the engine, and causes a problem of inducing an engine stall.

Therefore, in the supply pump of this embodiment, when bubbles are present in the fuel filled in the pressurizing chamber 6 in the suction stroke, the first seal of the cylinder body 4 is generated by the flow of fuel in the next pressure feed stroke. 2 and 3 for the purpose of preventing bubbles from collapsing and generating erosion (erosion) at a boundary portion a formed between the surface 51 and the second seal surface 57 of the stopper member 9. As shown in FIG. 2, an annular concave groove 62 as a flow blocking portion is provided on the plunger side end surface of the stopper member 9 of the electromagnetic valve.
The concave groove bottom surface 64 of the concave groove 62 is not provided on the same plane as the boundary portion a, and is connected to the boundary portion a through a predetermined step.

Here, the stopper member 9 is provided with a plunger-side end surface (the groove bottom surface 64 of the groove 62) that closes the opening end of the cylinder 5 and forms the pressurizing chamber 6 with the plunger 3. That is, the above-described flow blocking portion is a structure in which the boundary portion a between the first seal surface 51 and the second seal surface 57 and the groove bottom surface 64 of the groove 62 are not provided on the same plane. is there.
Further, in the supply pump of this embodiment, the flow allowance that allows the fuel flow to both sides in the circumferential direction toward one communication hole 45 out of the plurality of communication holes 45 that penetrates the stopper member 9 in the plate thickness direction. As a portion, an annular groove bottom surface 64, a cylindrical inner wall 65, and a cylindrical peripheral wall 69 are provided.

In the pre-stroke period, the typical fuel flow in the pressurizing chamber 6 of the supply pump is the fuel flow shown in FIGS.
In the fuel flow in the pressurizing chamber 6, the fuel flow mainly toward one side (upper side in the drawing) in the axial direction toward each communication hole 45 of the stopper member 9 is as shown in FIG. After passing through 45, the fuel flows to the fuel gallery 11 through the fuel intake passage.
On the other hand, in the fuel flow in the pressurizing chamber 6, the fuel flow outward in the radial direction mainly along the lower end surface 56 of the central protruding wall 63 of the stopper member 9 is an inclined groove as shown in FIG. Without entering 61, it enters the recessed groove 62 of the stopper member 9.

Accordingly, the fuel flow radially outward toward the boundary portion a formed between the first seal surface 51 and the second seal surface 57 out of the fuel flow radially outward in the pressurizing chamber 6. Be disturbed. For this reason, even when the fuel containing the bubbles flows into the pressurizing chamber 6 when the movement direction of the plunger 3 is the fuel suction direction, the bubbles contained in the fuel are transferred to the first seal surface 51 and the second seal surface. 57, it becomes difficult to concentrate on the boundary portion a formed between the first and second portions 57, that is, the inner side of the inclined groove 61.
Therefore, since the occurrence of cavitation erosion at the boundary portion a can be reduced, the fuel in the pressurizing chamber 6 can be prevented from leaking to the fuel gallery side when the electromagnetic valve is closed. Thereby, when the moving direction of the plunger 3 is the fuel pressurizing direction, the fuel sucked into the pressurizing chamber 6 can be pressurized to increase the pressure, and the high-pressure fuel can be discharged to the common rail side.
As a result, high pressure fuel can be supplied to each cylinder of the engine, so that engine stall can be prevented from being induced. Note that the deeper the groove depth of the recessed groove 62 recessed in the moving direction of the plunger 3 (fuel pressurizing direction) than the lower end surface 56 and the second seal surface 57 of the central protruding wall 63 is, the greater the radial direction toward the boundary portion a. The effect of hindering the outward fuel flow can be enhanced.

Here, the fuel injection pump described in Patent Document 2 is for a gasoline engine that uses a relatively soft gasket as a seal member that tightly seals the seat surface of the stopper and the seat surface of the cylinder member. .
On the other hand, the supply pump of the present embodiment is used for an ultrahigh pressure fuel pump for a diesel engine. In the case of such an ultra-high pressure fuel pump, when a gasket made of a relatively soft material is used as the seal member, there arises a problem that the gasket is deformed or damaged by the pressure in the pressurizing chamber.
For this reason, in the case of an ultra-high pressure fuel pump for a diesel engine, the stopper member 9 is directly connected to the cylinder body 4 by the screw fastening axial force of the solenoid valve without using a seal member between the cylinder body 4 and the stopper member 9. The first seal surface 51 is closely attached.

[Configuration of Example 2]
4 and 5 show a supply pump (Example 2) to which the high-pressure fuel pump of the present invention is applied.
Here, the same reference numerals as those in the first embodiment indicate the same configuration or function, and the description thereof is omitted.

The stopper member 9 of the present embodiment eliminates the central projecting wall 63 and the peripheral wall 66 of the first embodiment, and forms the concave groove 62 and the concave groove bottom surface 64 of the first embodiment in a circular shape.
Further, the concave groove 62 as the flow blocking portion includes a cylindrical inner wall 65 extending in the circumferential direction of the stopper member 9 as in the first embodiment. The inner wall 65 has the same inner diameter as the inner diameter of the cylinder 5. The concave groove 62 has a circular concave groove bottom face 64 connected to the second seal surface 57 via a predetermined cylindrical step.
The concave groove bottom surface 64 of the concave groove 62 constitutes a circular plunger side end surface that closes the opening end of the cylinder 5 and forms the pressurizing chamber 6 with the plunger 3. That is, the above-described flow blocking portion is a structure in which the boundary portion a between the first seal surface 51 and the second seal surface 57 and the groove bottom surface 64 of the groove 62 are not provided on the same plane. is there.

On the upper end surface of the stopper member 9 shown in the figure, a valve stopper surface 44 is provided that contacts the spool valve 7 of the electromagnetic valve and restricts the movement range (full lift amount) of the spool valve 7. Further, the stopper member 9 is formed with a communication hole 45 that communicates the valve accommodating chamber 25 that accommodates the valve portion 42 of the spool valve 7 so as to be reciprocally movable and the pressurizing chamber 6 in which fuel is pressurized by the plunger 3. ing. The communication holes 45 have a plurality of communication holes 45 provided at equal intervals on the same circumference of the stopper member 9.
The concave groove bottom surface 64 and the inner wall 65 have a function as a “flow allowing portion” in the claims.
As described above, the supply pump of this embodiment has the same effect as that of the first embodiment. Note that the deeper the groove depth of the concave groove 62 that is recessed in the movement direction of the plunger 3 (fuel pressurization direction) than the second seal surface 57 is, the greater the effect of inhibiting the fuel flow radially outward toward the boundary portion a. Can be increased.

[Configuration of Example 3]
6 and 7 show a supply pump (Example 3) to which the high-pressure fuel pump of the present invention is applied.
Here, the same reference numerals as those in the first and second embodiments indicate the same configuration or function, and the description thereof will be omitted.

The stopper member 9 of the present embodiment is provided with an annular flange 52 that is in close contact with the first seal surface 51 of the cylinder body 4 and an inner peripheral side of the flange 52. And a circular cover 53 that forms a pressurizing chamber 6 between the plunger 3 and the plunger 3.
An annular second sealing surface 57 that seals the pressurizing chamber 6 in close contact with the first sealing surface 51 of the cylinder body 4 is provided on the lower end surface of the flange 52 in the figure. Further, an annular fourth seal surface 59 is provided on the upper end surface of the flange 52 in the drawing so as to tightly seal with the third seal surface 58 of the valve body 8.

The cover 53 is thicker than the flange 52. The cover 53 is provided with a protruding wall 71 that protrudes in the moving direction of the plunger 3 (fuel intake direction) from the second seal surface 57. The protruding wall 71 corresponds to a “flow blocking portion” in the claims.
The protruding wall 71 includes a circular protruding end surface 72 connected to the second seal surface 57 via a predetermined cylindrical step (outer wall 74). The protruding end surface 72 is a plunger-side end surface that forms the pressurizing chamber 6 with the plunger 3. Further, the protruding end surface 72 is not provided on the same plane as the second seal surface 57. The outlet openings of the plurality of communication holes 45 and the other end side openings of the through holes 46 are opened at the projecting end surface 72.

A cylindrical outer wall 74 is provided on the outer peripheral surface of the projecting wall 71 to form a throttle 73 between the inner surface of the cylinder 5 (cylinder inner surface).
The protruding end surface 72 constitutes a circular plunger-side end surface that closes the opening end of the cylinder 5 and forms the pressurizing chamber 6 with the plunger 3. That is, the above-described flow blocking portion is a structure in which the boundary portion a between the first seal surface 51 and the second seal surface 57 and the protruding end surface 72 of the protruding wall 71 are not provided on the same plane. .
As described above, in the supply pump of the present embodiment, the boundary portion a formed between the first seal surface 51 and the second seal surface 57 communicates with the pressurizing chamber 6 through the restriction 73. . That is, since the gap between the cylinder inner surface and the outer wall 74 is narrowed, the fuel flow in the pressurizing chamber 6 hardly reaches the back side of the inclined groove 61, that is, the boundary portion a.
Therefore, the same effects as those of the first and second embodiments are obtained. Note that the greater the amount of protrusion of the protruding wall 71 that protrudes in the movement direction (fuel suction direction) of the plunger 3 than the second seal surface 57, the higher the effect of inhibiting the fuel flow outward in the radial direction toward the boundary portion a. be able to.

[Configuration of Example 4]
8 and 9 show a supply pump (Example 4) to which the high-pressure fuel pump of the present invention is applied.
Here, the same reference numerals as in the first to third embodiments indicate the same configuration or function, and the description thereof is omitted.

The supply pump of the present embodiment includes a feed pump 81, an electromagnetic fuel metering valve 82, a check valve structure suction valve, a plunger pump, a check valve structure discharge valve, and the like. This supply pump is a type of high-pressure fuel pump that uses one electromagnetic fuel metering valve 82 to meter the amount of fuel sucked into the plunger pumps of a plurality of cylinders by adjusting the opening area of the valve hole.
The plunger pump includes a plunger 3 and a cylinder body 4.
The plunger 3 is pressed against the cam ring 84 mounted around the eccentric cam 83 of the camshaft 1 by the biasing force of the plunger spring 19.

The discharge valve includes a valve 85 and a return spring 86. The valve 85 and the return spring 86 are accommodated between the cylinder body 4 and the pipe joint 13.
The intake valve includes a spool valve 7, a valve body 8, and a return spring 87. The valve body 8 of the intake valve corresponds to a “cover member” in the claims. The valve body 8 is configured such that the first sealing surface 51 of the cylinder body 4 and the fastening body 88 are coupled by a screw fastening axial force generated when the fastening body 88 is coupled (connected) to the fastening portion 10 of the cylinder body 4 by screw fastening. It is held and fixed in a state of being sandwiched between the third seal surface 58.

A conical surface (taper) -shaped valve seat surface 41 is provided on the upper end surface of the valve body 8 in the drawing so as to come into contact with the spool valve 7 of the intake valve and restrict the movement range (zero lift amount) of the spool valve 7.
An annular second seal surface 57 that seals the pressurizing chamber 6 in close contact with the first seal surface 51 of the cylinder body 4 is provided on the lower end surface of the flange 52 of the valve body 8. In addition, an annular fourth seal surface 59 is provided on the upper end surface of the flange 52 in the drawing so as to tightly seal the third seal surface 58 of the fastening body 88.
Further, the valve body 8 has a function as a valve accommodating chamber for accommodating the valve portion 42 of the spool valve 7 so as to be reciprocally movable, and fuel is supplied by the fuel intake hole (flow path) 24 of the valve body 8 and the plunger 3. A communication hole 45 communicating with the pressurizing chamber 6 to be pressurized is formed.

A spring seat 89 that holds the end portion of the return spring 87 is provided on the upper end surface of the central portion of the valve body 8 in the figure. In addition, a plunger-side end surface that forms a pressurizing chamber 6 with the plunger 3 is provided on the lower end surface of the central portion of the valve body 8. An annular groove 62 that is recessed in the movement direction of the plunger 3 (fuel pressurization direction) from the second seal surface 57 is provided on the end surface on the plunger side.
The concave groove 62 corresponds to a “flow inhibiting portion” in the claims. The concave groove 62 includes a cylindrical inner wall 65 extending in the circumferential direction of the valve body 8. The inner wall 65 has the same inner diameter as the inner diameter of the cylinder 5. The concave groove 62 has an annular concave groove bottom surface 64 connected to the second seal surface 57 via a predetermined cylindrical step.
The concave groove bottom surface 64 of the concave groove 62 constitutes an annular plunger side end surface that closes the opening end of the cylinder 5 and forms the pressurizing chamber 6 with the plunger 3.
Further, the concave groove bottom surface 64 and the inner wall 65 have a function as a “flow allowing portion” in the claims.
As described above, the supply pump of this embodiment has the same effects as those of Embodiments 1 to 3. Note that the deeper the groove depth of the concave groove 62 that is recessed in the movement direction of the plunger 3 (fuel pressurization direction) than the second seal surface 57 is, the greater the effect of inhibiting the fuel flow radially outward toward the boundary portion a. Can be increased.

[Modification]
In this embodiment, the example in which the high-pressure fuel pump of the present invention is applied to a supply pump used in a common rail fuel injection system has been described. However, the high-pressure fuel pump of the present invention is used in a fuel injection device that does not have a common rail. The present invention may be applied to a distributed fuel injection pump or a row fuel injection pump.

In the present embodiment, the example in which the high-pressure fuel pump of the present invention is applied to a fuel supply pump for an internal combustion engine that uses liquefied gas fuel such as dimethyl ether (DME) or liquefied petroleum gas (LPG) as fuel has been described. The high-pressure fuel pump of the present invention is for an internal combustion engine that uses, as a fuel, a DME mixed fuel obtained by mixing DME and diesel oil (light oil) at an arbitrary ratio, particularly a liquefied gas fuel containing a component that vaporizes under atmospheric pressure. It may be applied to the fuel supply pump.
Further, diesel oil (light oil) or gasoline oil may be used as the fuel supplied to the internal combustion engine.

In the present embodiment, a protruding wall 71 protruding in the movement direction (fuel suction direction) of the plunger 3 from the second seal surface 57 is provided as the flow blocking portion, but the protruding end surface of the protruding wall 71 as the flow blocking portion. 72 may be provided with the concave groove 62 of the first or second embodiment.
Further, the valve body 8 of the fourth embodiment may be provided with a protruding wall 71 that protrudes in the movement direction of the plunger 3 (fuel intake direction) from the second seal surface 57.

3 Plunger 4 Cylinder body (cylinder member)
5 Cylinder 6 Pressurizing chamber 8 Valve body (cover member)
9 Stopper member (cover member)
51 First seal surface 57 Second seal surface 62 Concave groove (flow blocking portion)
71 Concave groove (flow blocking part)

Claims (6)

(A) a reciprocating plunger (3);
(B) A cylindrical cylinder (5) which is open at least at one end and into which the plunger (3) is fitted, and an annular first sealing surface extending radially outward from the opening end of the cylinder (5). A cylinder member (4) having (51) and supporting the plunger (3) in a reciprocable manner;
(C) It has an annular second seal surface (57) that seals closely against the first seal surface (51) of the cylinder member (4), and closes the open end of the cylinder (5) to (3) and a cover member (8, 9) forming a pressurizing chamber (6),
In the high-pressure fuel pump that pressurizes the fuel sucked into the pressurizing chamber (6) by the reciprocating movement of the plunger (3),
The cover member (8, 9) includes the first seal surface (51) in the fuel flow in the pressurizing chamber (6) when the moving direction of the plunger (3) is the fuel pressurizing direction. And a flow inhibition part (62, 71) for inhibiting the fuel flow radially outward toward the boundary part (a) formed between the second seal surface (57) and the second seal surface (57),
The flow blocking portion (62, 71) has a groove (62) that is recessed in the moving direction of the plunger (3) from the second seal surface (57),
The concave groove (62) has a concave groove bottom surface (64) connected to the second seal surface (57) via a predetermined step (68),
The cover member (8, 9) is made of a single metal plate, and the concave groove bottom surface (64) is provided on the metal plate . The high-pressure fuel pump according to claim 1,
The concave groove (62) has a cylindrical inner wall (65) extending in the circumferential direction of the cover member (8, 9),
The high-pressure fuel pump, wherein the inner wall (65) has an inner diameter substantially the same as the inner diameter of the cylinder (5) . (A) a reciprocating plunger (3);
(B) A cylindrical cylinder (5) which is open at least at one end and into which the plunger (3) is fitted, and an annular first sealing surface extending radially outward from the opening end of the cylinder (5). A cylinder member (4) having (51) and supporting the plunger (3) in a reciprocable manner;
(C) It has an annular second seal surface (57) that seals closely against the first seal surface (51) of the cylinder member (4), and closes the open end of the cylinder (5) to Cover members (8, 9) forming a pressurizing chamber (6) between (3) and
With
In the high-pressure fuel pump that pressurizes the fuel sucked into the pressurizing chamber (6) by the reciprocating movement of the plunger (3),
The cover member (8, 9) includes the first seal surface (51) in the fuel flow in the pressurizing chamber (6) when the moving direction of the plunger (3) is the fuel pressurizing direction. And a flow inhibition part (62, 71) for inhibiting the fuel flow radially outward toward the boundary part (a) formed between the second seal surface (57) and the second seal surface (57),
The flow blocking portion (62, 71) has a protruding wall (71) protruding in the moving direction of the plunger (3) from the second sealing surface (57),
The high-pressure fuel pump , wherein the protruding wall (71) has a protruding end surface (72) connected to the second seal surface (57) via a predetermined step (74) . The high-pressure fuel pump according to claim 3 ,
The high-pressure fuel pump, wherein the protruding wall (71) has an outer wall (74) that forms a throttle (73) between the projecting wall (71) and an inner diameter surface of the cylinder (5) . The high-pressure fuel pump according to any one of claims 1 to 4 ,
A valve body (7) for opening and closing the flow paths (21 to 24) for supplying fuel to the pressurizing chamber (6);
The cover members (8, 9) contact the valve body (7) and restrict the movement range of the valve body (7), and the flow paths (21-24) or A high-pressure fuel pump having a communication hole (45) for communicating the valve body housing chamber (25) for movably housing the valve body (7) and the pressurizing chamber (6) . The high-pressure fuel pump according to claim 5 ,
The high-pressure fuel pump, wherein the cover member (8, 9) has a flow permission portion (64-66) that allows fuel flow in a direction toward the communication hole (45) .

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