JP2021148043A - Fuel pump - Google Patents

Abstract

To provide a fuel pump which can reduce a dead volume of a relief valve mechanism, and can secure a fuel passage.SOLUTION: A relief valve mechanism 4 of a fuel pump has: a relief valve 43 for opening and closing a flow passage progressing to a second chamber 1b (relief valve chamber) from a discharge valve chamber; a relief valve holder 42 engaged with the relief valve 43; and a coil-shaped relief spring 41 for energizing the relief valve holder 42 to the discharge valve chamber side. A suction passage 1d (communication hole) is formed between a suction valve chamber 30 and the second chamber 1b, and the relief valve holder 42 has an insertion part 42b which is inserted into the relief spring 41 in a radial direction. Then, a tip of the insertion part 42b is arranged in the vicinity of an end part at a side opposite to an insertion side to which the insertion part 42b of the relief spring 41 is inserted, and an opening area of the suction passage 1d is larger than an area of the tip of the insertion part 42b.SELECTED DRAWING: Figure 6

Description

The present invention relates to a fuel pump that supplies fuel to an engine at a high pressure.

The fuel pump is described in, for example, Patent Document 1. The high-pressure fuel supply pump described in Patent Document 1 includes a housing, an intake valve, a discharge valve, and a relief valve. The housing has a cylinder, which is a stepped tubular space that accommodates a cylinder liner that slidably holds the plunger and forms a pressurizing chamber. The suction valve opens without supplying a current to the electromagnetic solenoid, and when a current is supplied to the electromagnetic solenoid, the valve opens and sucks fuel into the pressurizing chamber.

The discharge valve is assembled in the discharge valve accommodating portion of the housing, and the discharge valve accommodating portion communicates with the pressurizing chamber through the fuel discharge hole. The high-pressure fuel pressurized in the pressurizing chamber is supplied to the discharge valve. The discharge valve opens when the pressure of the supplied fuel exceeds a predetermined pressure, and the fuel that has passed through the discharge valve is pressure-fed to the accumulator.

Further, the relief valve is assembled to the relief valve accommodating portion of the housing, and the relief valve accommodating portion communicates with the high pressure region on the downstream side of the discharge valve and communicates with the pressurizing chamber via the communication passage. There is. The relief valve opens when the pressure of the fuel in the high pressure region exceeds a specific pressure, and returns the high pressure fuel to the pressurizing chamber.

JP-A-2019-2374

However, in the high-pressure fuel supply pump described in Patent Document 1, a dead volume is generated between the valve holder in the relief valve and the bottom surface of the relief valve accommodating portion, which causes a decrease in the compression efficiency of the relief valve. rice field. Further, when the dead volume is reduced in the relief valve, there arises a problem that the fuel passage is narrowed.

An object of the present invention is to consider the above problems and to provide a fuel pump capable of reducing the dead volume of the relief valve mechanism and securing a fuel passage.

In order to solve the above problems and achieve the object of the present invention, the fuel pump of the present invention has a suction valve mechanism arranged in a body having a pressurizing chamber and a suction valve chamber provided on the upstream side of the pressurizing chamber. A discharge valve mechanism arranged in a discharge valve chamber provided on the downstream side of the pressurizing chamber and a relief valve mechanism arranged in a relief valve chamber provided on the downstream side of the pressurizing chamber are provided. The suction valve mechanism discharges fuel to the pressurizing chamber. The relief valve mechanism opens the valve when the difference between the pressure in the discharge valve chamber and the pressure in the relief valve chamber exceeds a set value, and returns the fuel to the pressurizing chamber.

The relief valve mechanism has a relief valve that opens and closes the flow path from the discharge valve chamber to the relief valve chamber, a relief valve holder that engages with the relief valve, and a coil shape that urges the relief valve holder toward the discharge valve chamber side. Has a relief spring. A communication hole is formed between the suction valve chamber and the relief valve chamber, and the relief valve holder has an insertion portion inserted inside the relief spring in the radial direction. The tip of the insertion portion is arranged near the end of the relief spring on the side opposite to the insertion side into which the insertion portion is inserted, and the opening area of the communication hole is larger than the area of the tip of the insertion portion.

According to the fuel pump having the above configuration, the dead volume of the relief valve mechanism can be reduced and the fuel passage can be secured.
Issues, configurations, and effects other than those described above will be clarified by the following description of the embodiments.

It is an overall block diagram of the fuel supply system using the high pressure fuel supply pump which concerns on one Embodiment of this invention. It is a vertical sectional view (the 1) of the high pressure fuel supply pump which concerns on one Embodiment of this invention. It is a vertical sectional view (the 2) of the high pressure fuel supply pump which concerns on one Embodiment of this invention. It is a horizontal sectional view seen from above of the high pressure fuel supply pump which concerns on one Embodiment of this invention. FIG. 3 is a vertical sectional view (No. 3) of a high-pressure fuel supply pump according to an embodiment of the present invention. It is explanatory drawing which enlarges and shows the relief valve mechanism in the high pressure fuel supply pump which concerns on one Embodiment of this invention.

1. Embodiment Hereinafter, the high pressure fuel supply pump according to the embodiment of the present invention will be described. The common members in each figure are designated by the same reference numerals.

[Fuel supply system]
Next, a fuel supply system using a high-pressure fuel supply pump (fuel pump) according to the present embodiment will be described with reference to FIG.
FIG. 1 is an overall configuration diagram of a fuel supply system using a high-pressure fuel supply pump according to the present embodiment.

As shown in FIG. 1, the fuel supply system includes a high-pressure fuel supply pump (fuel pump) 100, an ECU (Engine Control Unit) 101, a fuel tank 103, a common rail 106, and a plurality of injectors 107. .. The parts of the high-pressure fuel supply pump 100 are integrally incorporated in the pump body 1.

The fuel in the fuel tank 103 is pumped by the feed pump 102 that is driven based on the signal from the ECU 101. The pumped fuel is pressurized to an appropriate pressure by a pressure regulator (not shown) and sent to the low pressure fuel suction port 51 of the high pressure fuel supply pump 100 through the low pressure pipe 104.

The high-pressure fuel supply pump 100 pressurizes the fuel supplied from the fuel tank 103 and pumps it to the common rail 106. A plurality of injectors 107 and a fuel pressure sensor 105 are mounted on the common rail 106. The plurality of injectors 107 are mounted according to the number of cylinders (combustion chambers), and inject fuel according to the drive current output from the ECU 101. The fuel supply system of the present embodiment is a so-called direct injection engine system in which the injector 107 injects fuel directly into the cylinder cylinder of the engine.

The fuel pressure sensor 105 outputs the detected pressure data to the ECU 101. The ECU 101 has an appropriate injection fuel amount (target injection fuel length) and an appropriate fuel pressure (target) based on the engine state amount (for example, crank rotation angle, throttle opening, engine rotation speed, fuel pressure, etc.) obtained from various sensors. Fuel pressure) etc. are calculated.

Further, the ECU 101 controls the drive of the high-pressure fuel supply pump 100 and the plurality of injectors 107 based on the calculation results such as the fuel pressure (target fuel pressure). That is, the ECU 101 has a pump control unit that controls the high-pressure fuel supply pump 100 and an injector control unit that controls the injector 107.

The high-pressure fuel supply pump 100 includes a pressure pulsation reducing mechanism 9, an electromagnetic suction valve mechanism 3 which is a capacity variable mechanism, a relief valve mechanism 4 (see FIG. 2), and a discharge valve mechanism 8. The fuel flowing in from the low-pressure fuel suction port 51 reaches the suction port 31b of the electromagnetic suction valve mechanism 3 via the pressure pulsation reduction mechanism 9 and the suction passage 10b.

The fuel that has flowed into the electromagnetic suction valve mechanism 3 passes through the valve portion 32, flows through the suction passage 1d formed in the pump body 1, and then flows into the pressurizing chamber 11. A plunger 2 is inserted into the pressurizing chamber 11 so as to be reciprocating. The plunger 2 reciprocates when power is transmitted by the cam 91 of the engine (see FIG. 2).

In the pressurizing chamber 11, fuel is sucked from the electromagnetic suction valve mechanism 3 in the descending stroke of the plunger 2, and the fuel is pressurized in the ascending stroke. When the fuel pressure in the pressurizing chamber 11 exceeds a predetermined value, the discharge valve mechanism 8 opens, and the high-pressure fuel is pressure-fed to the common rail 106 via the discharge passage 12a. The discharge of fuel by the high-pressure fuel supply pump 100 is operated by opening and closing the electromagnetic suction valve mechanism 3. Then, the opening and closing of the electromagnetic suction valve mechanism 3 is controlled by the ECU 101.

[High pressure fuel supply pump]
Next, the configuration of the high-pressure fuel supply pump 100 will be described with reference to FIGS. 2 to 6.
FIG. 2 is a vertical cross-sectional view (No. 1) of the high-pressure fuel supply pump 100 as viewed in a cross section orthogonal to the horizontal direction. FIG. 3 is a vertical cross-sectional view (No. 2) of the high-pressure fuel supply pump 100 as viewed in a cross section orthogonal to the horizontal direction. FIG. 4 is a horizontal cross-sectional view of the high-pressure fuel supply pump 100 as viewed in a cross section orthogonal to the vertical direction. Further, FIG. 5 is a vertical cross-sectional view (No. 3) of the high-pressure fuel supply pump 100 as viewed in a cross section orthogonal to the horizontal direction. FIG. 6 is an enlarged explanatory view showing the relief valve mechanism 4.

As shown in FIGS. 2 to 5, the pump body 1 of the high-pressure fuel supply pump 100 is formed in a substantially columnar shape. As shown in FIGS. 2 and 3, the pump body 1 is provided with a first chamber 1a, a second chamber 1b, a third chamber 1c, and a suction passage 1d inside. Further, the pump body 1 is in close contact with the fuel pump mounting portion 90 and is fixed by a plurality of bolts (screws) (not shown).

The first chamber 1a is a columnar space provided in the pump body 1, and the center line 1A of the first chamber 1a coincides with the center line of the pump body 1. One end of the plunger 2 is inserted into the first chamber 1a, and the plunger 2 reciprocates in the first chamber 1a. One end of the first chamber 1a and the plunger 2 forms a pressurizing chamber 11.

The second chamber 1b is a columnar space provided in the pump body 1, and the center line of the second chamber 1b is orthogonal to the center line of the pump body 1 (first chamber 1a). A relief valve chamber in which the relief valve mechanism 4 is arranged is formed in the second chamber 1b. The diameter of the second chamber 1b (relief valve chamber) is smaller than the diameter of the first chamber 1a.

Further, the first chamber 1a and the second chamber 1b are communicated with each other by a circular communication hole 1e. The diameter of the communication hole 1e is the same as the diameter of the first chamber 1a, and the communication hole 1e extends one end of the first chamber 1a. The diameter of the communication hole 1e is larger than the outer diameter of the plunger 2. As a result, the plunger 2 reciprocating in the pressurizing chamber 11 does not collide with the periphery of the communication hole 1e, and the durability of the plunger 2 can be improved.

Further, the center line of the communication hole 1e is orthogonal to the center line of the second chamber 1b. As a result, the fuel that has passed through the relief valve mechanism 4 can be efficiently passed through the communication hole 1e so as not to hinder the improvement of the relief performance. Further, the shape of the pump body 1 can be prevented from becoming complicated, and the productivity of the pump body 1 and the high-pressure fuel supply pump 100 can be improved.

As shown in FIGS. 3 and 5, the diameter of the communication hole 1e is larger than the diameter of the second chamber 1b. The communication hole 1e has a tapered surface 1f whose diameter decreases toward the second chamber 1b in a cross section orthogonal to the center line of the second chamber 1b. As a result, the fuel that has passed through the relief valve mechanism 4 arranged in the second chamber 1b can smoothly return to the pressurizing chamber 11 along the tapered surface 1f.

The third chamber 1c is a columnar space provided in the pump body 1 and is continuous with the other end of the first chamber 1a. The center line of the third chamber 1c coincides with the center line 1A of the first chamber 1a and the center line of the pump body 1, and the diameter of the third chamber 1c is larger than the diameter of the first chamber 1a. A cylinder 6 for guiding the reciprocating movement of the plunger 2 is arranged in the third chamber 1c. As a result, the end surface of the cylinder 6 can be brought into contact with the step portion between the first chamber 1a and the third chamber 1c, and the cylinder 6 can be prevented from being displaced toward the first chamber 1a. can.

The cylinder 6 is formed in a cylindrical shape, and is press-fitted into the third chamber 1c of the pump body 1 on the outer peripheral side thereof. Then, one end of the cylinder 6 is in contact with the top surface of the third chamber 1c (the step portion between the first chamber 1a and the third chamber 1c). The plunger 2 is slidably in contact with the inner peripheral surface of the cylinder 6.

An O-ring 93 showing a specific example of the seat member is interposed between the fuel pump mounting portion 90 and the pump body 1. The O-ring 93 prevents engine oil from leaking to the outside of the engine (internal combustion engine) through between the fuel pump mounting portion 90 and the pump body 1.

A tappet 92 is provided at the lower end of the plunger 2. The tappet 92 converts the rotational motion of the cam 91 attached to the camshaft of the engine into a vertical motion and transmits it to the plunger 2. The plunger 2 is urged toward the cam 91 by a spring 16 via a retainer 15 and is crimped to the tappet 92. The tappet 92 reciprocates as the cam 91 rotates. The plunger 2 reciprocates together with the tappet 92 to change the volume of the pressurizing chamber 11.

Further, a seal holder 17 is arranged between the cylinder 6 and the retainer 15. The seal holder 17 is formed in a cylindrical shape into which the plunger 2 is inserted, and has an auxiliary chamber 17a at the upper end portion on the cylinder 6 side. Further, the seal holder 17 holds the plunger seal 18 at the lower end portion on the retainer 15 side.

The plunger seal 18 is slidably in contact with the outer periphery of the plunger 2, and when the plunger 2 reciprocates, the fuel in the sub chamber 17a is sealed so that the fuel in the sub chamber 17a does not flow into the engine. There is. Further, the plunger seal 18 prevents the lubricating oil (including the engine oil) that lubricates the sliding portion in the engine from flowing into the inside of the pump body 1.

In FIG. 2, the plunger 2 reciprocates in the vertical direction. When the plunger 2 is lowered, the volume of the pressurizing chamber 11 is expanded, and when the plunger 2 is raised, the volume of the pressurizing chamber 11 is decreased. That is, the plunger 2 is arranged so as to reciprocate in the direction of expanding and contracting the volume of the pressurizing chamber 11.

The plunger 2 has a large diameter portion 2a and a small diameter portion 2b. When the plunger 2 reciprocates, the large diameter portion 2a and the small diameter portion 2b are located in the sub chamber 17a. Therefore, the volume of the sub chamber 17a increases or decreases due to the reciprocating movement of the plunger 2.

The sub chamber 17a communicates with the low pressure fuel chamber 10 by a fuel passage 10c (see FIG. 5). When the plunger 2 is lowered, a fuel flow is generated from the sub chamber 17a to the low pressure fuel chamber 10, and when the plunger 2 is raised, a fuel flow is generated from the low pressure fuel chamber 10 to the sub chamber 17a. As a result, the fuel flow rate inside and outside the pump in the suction stroke or the return stroke of the high-pressure fuel supply pump 100 can be reduced, and the pressure pulsation generated inside the high-pressure fuel supply pump 100 can be reduced.

As shown in FIG. 3, a low-pressure fuel chamber 10 is provided above the pump body 1 of the high-pressure fuel supply pump 100, and a suction joint 5 is attached to the side surface of the pump body 1. The suction joint 5 is connected to a low pressure pipe 104 through which fuel supplied from the fuel tank 103 (see FIG. 1) is passed. The fuel in the fuel tank 103 is supplied to the inside of the pump body 1 from the suction joint 5.

The suction joint 5 has a low pressure fuel suction port 51 connected to the low pressure pipe 104 and a suction flow path 52 communicating with the low pressure fuel suction port 51. The fuel that has passed through the suction flow path 52 passes through the suction filter 53 provided inside the pump body 1 and is supplied to the low-pressure fuel chamber 10. The suction filter 53 removes foreign matter present in the fuel and prevents the foreign matter from entering the high-pressure fuel supply pump 100.

The low-pressure fuel chamber 10 is provided with a low-pressure fuel flow path 10a and a suction passage 10b (see FIG. 2). A pressure pulsation reducing mechanism 9 is provided in the low pressure fuel flow path 10a. When the fuel flowing into the pressurizing chamber 11 is returned to the suction passage 10b through the electromagnetic suction valve mechanism 3 in the opened valve state, pressure pulsation occurs in the low pressure fuel chamber 10. The pressure pulsation reducing mechanism 9 reduces that the pressure pulsation generated in the high-pressure fuel supply pump 100 spreads to the low-pressure pipe 104.

The pressure pulsation reduction mechanism 9 is formed of a metal diaphragm damper in which two corrugated disk-shaped metal plates are bonded together on the outer periphery thereof and an inert gas such as argon is injected therein. The metal diaphragm damper of the pressure pulsation reducing mechanism 9 absorbs or reduces the pressure pulsation by expanding and contracting.

The suction passage 10b communicates with the suction port 31b (see FIG. 2) of the electromagnetic suction valve mechanism 3, and the fuel passing through the low pressure fuel flow path 10a passes through the suction passage 10b to the suction port of the electromagnetic suction valve mechanism 3. Reach 31b.

As shown in FIGS. 2 and 4, the electromagnetic suction valve mechanism 3 is inserted into the suction valve chamber 30 formed in the pump body 1. The suction valve chamber 30 is provided on the upstream side (suction passage 10b side) of the pressurizing chamber 11 and is formed in a horizontal hole extending in the horizontal direction. The electromagnetic suction valve mechanism 3 has a suction valve seat 31 press-fitted into the suction valve chamber 30, a valve portion 32, a rod 33, a rod urging spring 34, an electromagnetic coil 35, and an anchor 36. ..

The suction valve seat 31 is formed in a cylindrical shape, and a seating portion 31a is provided on the inner peripheral portion. Further, the suction valve seat 31 is formed with a suction port 31b that reaches the inner peripheral portion from the outer peripheral portion. The suction port 31b communicates with the suction passage 10b in the low-pressure fuel chamber 10 described above.

In the suction valve chamber 30, a stopper 37 facing the seating portion 31a of the suction valve seat 31 is arranged, and the valve portion 32 is arranged between the stopper 37 and the seating portion 31a. Further, a valve urging spring 38 is interposed between the stopper 37 and the valve portion 32. The valve urging spring 38 urges the valve portion 32 toward the seating portion 31a.

The valve portion 32 abuts on the seating portion 31a to close the communication portion between the suction port 31b and the pressurizing chamber 11. When the valve portion 32 closes the communication portion between the suction port 31b and the pressurizing chamber 11, the electromagnetic suction valve mechanism 3 is closed. On the other hand, the valve portion 32 abuts on the stopper 37 to open the communication portion between the suction port 31b and the pressurizing chamber 11. When the valve portion 32 opens the communication portion between the suction port 31b and the pressurizing chamber 11, the electromagnetic suction valve mechanism 3 is opened.

The rod 33 penetrates the tubular hole of the suction valve seat 31, and one end of the rod 33 is in contact with the valve portion 32. The rod urging spring 34 urges the valve portion 32 via the rod 33 in the valve opening direction on the stopper 37 side. One end of the rod urging spring 34 is engaged with the other end of the rod 33, and the other end of the rod urging spring 34 is engaged with a magnetic core 39 arranged so as to surround the rod urging spring 34. ing.

The anchor 36 faces the end face of the magnetic core 39. Further, the anchor 36 is engaged with a flange provided in the middle portion of the rod 33. The electromagnetic coil 35 is arranged so as to go around the magnetic core 39. A terminal member 40 is electrically connected to the electromagnetic coil 35, and a current flows through the terminal member 40.

In a non-energized state in which no current is flowing through the electromagnetic coil 35, the rod 33 is urged in the valve opening direction by the urging force of the rod urging spring 34, and the valve portion 32 is pressed in the valve opening direction. As a result, the valve portion 32 is separated from the seating portion 31a and comes into contact with the stopper 37, and the electromagnetic suction valve mechanism 3 is in the valve open state. That is, the electromagnetic suction valve mechanism 3 is a normally open type that opens in a non-energized state.

In the valve open state of the electromagnetic suction valve mechanism 3, the fuel of the suction port 31b passes between the valve portion 32 and the seating portion 31a, and passes through a plurality of fuel passage holes (not shown) of the stopper 37 and the suction passage 1d. It flows into the pressurizing chamber 11. In the valve open state of the electromagnetic suction valve mechanism 3, the valve portion 32 comes into contact with the stopper 37, so that the position of the valve portion 32 in the valve opening direction is restricted. The gap existing between the valve portion 32 and the seating portion 31a in the valve open state of the electromagnetic suction valve mechanism 3 is the movable range of the valve portion 32, and this is the valve opening stroke.

When a current flows through the electromagnetic coil 35, the anchor 36 is attracted in the valve closing direction by the magnetic attraction force of the magnetic core 39. As a result, the anchor 36 moves against the urging force of the rod urging spring 34 and comes into contact with the magnetic core 39. When the anchor 36 moves in the valve closing direction on the magnetic core 39 side, the rod 33 with which the anchor 36 engages moves together with the anchor 36. As a result, the valve portion 32 is released from the urging force in the valve opening direction and moves in the valve closing direction by the urging force by the valve urging spring 38. Then, when the valve portion 32 comes into contact with the seating portion 31a of the suction valve seat 31, the electromagnetic suction valve mechanism 3 is closed.

As shown in FIGS. 4 and 5, the discharge valve mechanism 8 is arranged in the discharge valve chamber 80 provided on the outlet side (downstream side) of the pressurizing chamber 11. The discharge valve mechanism 8 includes a discharge valve seat 81 that communicates with the pressurizing chamber 11, a valve portion 82 that communicates with and separates from the discharge valve seat 81, and a discharge valve spring 83 that urges the valve portion 82 toward the discharge valve seat 81. It has a discharge valve stopper 84 that determines the stroke (moving distance) of the valve portion 82.

Further, the discharge valve mechanism 8 has a plug 85 that blocks the leakage of fuel to the outside. The discharge valve stopper 84 is press-fitted into the plug 85. The plug 85 is joined to the pump body 1 by welding at the welded portion 86. The discharge valve chamber 80 is opened and closed by the valve portion 82. The discharge valve chamber 80 communicates with the discharge valve chamber passage 87. The discharge valve chamber passage 87 is formed in the pump body 1.

The pump body 1 is provided with a horizontal hole communicating with the second chamber 1b (relief valve chamber) shown in FIG. 2, and a discharge joint 12 is inserted into the horizontal hole. The discharge joint 12 has the above-mentioned discharge passage 12a communicating with the lateral hole of the pump body 1 and the discharge valve chamber passage 87, and the fuel discharge port 12b which is one end of the discharge passage 12a. The fuel discharge port 12b of the discharge joint 12 communicates with the common rail 106. The discharge joint 12 is fixed to the pump body 1 by welding by the welded portion 12c.

When there is no difference in fuel pressure (fuel differential pressure) between the pressurizing chamber 11 and the discharge valve chamber 80 (discharge valve chamber passage 87), the valve portion 82 is subjected to the urging force of the discharge valve spring 83 to cause the discharge valve seat 81. The discharge valve mechanism 8 is closed. When the fuel pressure in the pressurizing chamber 11 becomes larger than the fuel pressure in the discharge valve chamber 80 (discharge valve chamber passage 87), the valve portion 82 moves against the urging force of the discharge valve spring 83 and discharges. The valve mechanism 8 is in the valve open state.

When the discharge valve mechanism 8 is opened, the (high pressure) fuel in the pressurizing chamber 11 passes through the discharge valve mechanism 8 and reaches the discharge valve chamber 80 (discharge valve chamber passage 87). Then, the fuel that has reached the discharge valve chamber passage 87 is discharged to the common rail 106 (see FIG. 1) through the fuel discharge port 12b of the discharge joint 12. With the above configuration, the discharge valve mechanism 8 functions as a check valve that limits the fuel flow direction.

The relief valve mechanism 4 shown in FIGS. 2 and 6 operates when a problem occurs in the common rail 106 or a member beyond the common rail 106 and the pressure of the common rail 106 exceeds a predetermined pressure, and the discharge passage 12a is operated. It is a valve configured to return the fuel inside to the pressurizing chamber 11. The discharge passage 12a communicates with the discharge valve chamber 80 via the discharge valve chamber passage 87. Therefore, the pressure in the discharge passage 12a is the same as the pressure in the discharge valve chamber 80.

The relief valve mechanism 4 is opened when the difference between the pressure in the discharge valve chamber 80 (discharge valve chamber passage 87) and the pressure in the second chamber 1b (relief valve chamber) exceeds a set value. The relief valve mechanism 4 is arranged at a position higher than that of the discharge valve mechanism 8 (see FIG. 5) in the direction in which the plunger 2 reciprocates (vertical direction).

The relief valve mechanism 4 includes a relief spring 41, a relief valve holder 42, a relief valve 43, and a seat member 44. The relief valve mechanism 4 is inserted from the discharge joint 12 and arranged in the second chamber 1b (relief valve chamber). The relief spring 41 is a coil-shaped spring, and one end thereof is in contact with the pump body 1 (one end of the second chamber 1b). The other end of the relief spring 41 is in contact with the relief valve holder 42. The relief valve holder 42 is engaged with the relief valve 43, and the urging force of the relief spring 41 acts on the relief valve 43 via the relief valve holder 42.

The relief valve holder 42 has a contact portion 42a and an insertion portion 42b continuous with the contact portion 42a. The contact portion 42a is formed in a disk shape having an appropriate thickness. An engaging groove with which the relief valve 43 is engaged is formed on one flat surface of the contact portion 42a. Further, the insertion portion 42b protrudes from the other flat surface of the contact portion 42a, and the other end portion of the relief spring 41 comes into contact with the other flat surface.

The insertion portion 42b is formed in a columnar shape and is inserted inside the relief spring 41 in the radial direction. The tip of the insertion portion 42b opposite to the contact portion 42a is formed on a circular flat surface and is arranged near one end of the relief spring 41 (the seating surface of the relief spring 41). One end of the relief spring 41 is an end opposite to the insertion side (the other end) into which the insertion portion 42b of the relief spring 41 is inserted. The insertion portion 42b has a tapered portion 42c whose outer diameter decreases toward the tip end. The tapered portion 42c starts from the relief valve 43 side of the portion of the relief spring 41 where a gap is formed in the adjacent rings.

The relief spring 41 is interposed between one end of the second chamber 1b (around the suction passage 1d described later) and the contact portion 42a of the relief valve holder 42 in a compressed state, and is compressed to relieve. The valve holder 42 and the relief valve 43 are urged toward the seat member 44. Therefore, it is conceivable that adjacent rings come into contact with each other at both ends of the relief spring 41. Even if the tapered portion 42c is arranged at the portion where the adjacent rings are in contact with each other, the fuel between the relief spring 41 and the tapered portion 42c is suppressed from traveling outward in the radial direction of the relief spring 41.

On the other hand, as in the present embodiment, the tapered portion 42c is arranged in a portion of the relief spring 41 in which a gap is formed between adjacent rings. As a result, the fuel between the relief spring 41 and the tapered portion 42c easily travels outward in the radial direction of the relief spring 41 from between the adjacent rings in the relief spring 41. As a result, the fuel can be efficiently sucked into the pressurizing chamber 11.

The relief valve 43 is pressed by the urging force of the relief spring 41 and blocks the fuel passage of the seat member 44. The moving direction of the relief valve 43 (relief valve holder 42) is orthogonal to the direction in which the plunger 2 reciprocates, and is the same as the moving direction of the valve portion (suction valve) 32 in the electromagnetic suction valve mechanism 3. The center line of the relief valve mechanism 4 (the center line of the relief valve holder 42) is orthogonal to the center line of the plunger 2.

The seat member 44 has a fuel passage facing the relief valve 43, and the side of the fuel passage opposite to the relief valve 43 communicates with the discharge passage 12a. The movement of fuel between the pressurizing chamber 11 (upstream side) and the seat member 44 (downstream side) is blocked by the relief valve 43 contacting (adhering) to the seat member 44 and blocking the fuel passage.

When the pressure in the discharge valve chamber 80 (discharge valve chamber passage 87), the common rail 106, and the members beyond it becomes high, the difference from the pressure in the second chamber 1b (relief valve chamber) exceeds the set value. As a result, the fuel on the seat member 44 side presses the relief valve 43 and moves the relief valve 43 against the urging force of the relief spring 41. As a result, the relief valve 43 is opened, and the fuel in the discharge passage 12a returns to the pressurizing chamber 11 through the fuel passage of the seat member 44. Therefore, the pressure for opening the relief valve 43 is determined by the urging force of the relief spring 41.

The moving direction of the relief valve 43 (relief valve holder 42) in the relief valve mechanism 4 is different from the moving direction of the valve portion 82 in the discharge valve mechanism 8 described above. That is, the moving direction of the valve portion 82 in the discharge valve mechanism 8 is the first radial direction of the pump body 1, and the moving direction of the relief valve 43 in the relief valve mechanism 4 is different from the first radial direction of the pump body 1. Two radial directions. As a result, the discharge valve mechanism 8 and the relief valve mechanism 4 can be arranged at positions where they do not overlap each other in the vertical direction, and the space inside the pump body 1 can be effectively utilized to reduce the size of the pump body 1. Can be done.

As shown in FIG. 2, a suction passage 1d showing a specific example of the communication hole is provided between the suction valve chamber 30 and the second chamber 1b (relief valve chamber) in the pump body 1. The suction passage 1d is formed in a circular shape, and the direction of the central axis of the suction passage 1d is the same as the moving direction of the valve portion (suction valve) 32 in the electromagnetic suction valve mechanism 3. Further, in the direction of the central axis of the suction passage 1d, the central axis of the suction passage 1d overlaps with the central axis of the insertion portion 42b in the relief valve holder 42.

A part of the fuel in the suction valve chamber 30 flows into the pressurizing chamber 11 through the suction passage 1d and the second chamber 1b (relief valve chamber). The tip of the insertion portion 42b in the relief valve holder 42 faces the suction passage 1d. The tip of the insertion portion 42b is located closer to the suction passage 1d than the side surface of the plunger 2, and is arranged near the end of the relief spring 41 on the side opposite to the insertion side of the insertion portion 42b.

In this way, when the tip of the insertion portion 42b reaches the vicinity of one end of the relief spring 41, the dead space of the second chamber 1b (relief valve chamber) communicating with the pressurizing chamber 11 can be filled with the insertion portion 42b. .. As a result, the compression efficiency of the pressurizing chamber 11 including the second chamber 1b can be improved as compared with the case where the insertion portion 42b is not provided.

Further, the opening area of the suction passage 1d is larger than the area of the tip of the insertion portion 42b. That is, the diameter (diameter D) of the suction passage 1d is larger than the diameter (diameter d) of the tip of the insertion portion 42b. Thereby, a passage (fuel passage) through which the fuel passing through the suction passage 1d passes can be secured around the insertion portion 42b. As a result, the fuel that has passed through the suction passage 1d easily passes between the relief spring 41 and the insertion portion 42b.

In the present embodiment, by providing the insertion portion 42b, it is possible to secure a passage (fuel passage) through which the fuel passing through the suction passage 1d passes and to improve the compression efficiency of the pressurizing chamber 11 including the second chamber 1b. can. As a result, the volumetric efficiency can be improved as compared with the case where the insertion portion 42b is not provided. Volumetric efficiency is the discharge from the discharge valve mechanism 8 with respect to the moving distance from the lower start point of the plunger 2 where the volume of the pressurizing chamber 11 is most expanded to the upper start point of the plunger 2 where the volume of the pressurizing chamber 11 is most reduced. It is the ratio of the discharge amount of the fuel.

The fact that the tip of the insertion portion 42b is arranged near one end of the relief spring 41 also includes the fact that the tip of the insertion portion 42b is arranged in the suction passage 1d. Even when the tip of the insertion portion 42b is arranged in the suction passage 1d, it is possible to secure a space for fuel to pass between the suction passage 1d and the insertion portion 42b. Further, the dead space of the second chamber 1b (relief valve chamber) communicating with the pressurizing chamber 11 can be filled with the insertion portion 42b.

Further, a supply communication hole 1 g is provided between the suction valve chamber 30 and the pressurizing chamber 11 in the pump body 1. The supply communication hole 1 g is formed in a circular shape, and the central axis direction of the supply communication hole 1 g is the same as the moving direction of the valve portion (suction valve) 32 and the relief valve 43 in the electromagnetic suction valve mechanism 3. The supply communication hole 1g communicates with the first chamber 1a.

At least a part of the supply communication hole 1 g overlaps the operating range of the plunger 2 in the moving direction of the relief valve 43. At the upper start point of the plunger 2 where the volume of the pressurizing chamber 11 is most reduced, the side peripheral surface of the plunger 2 faces the supply communication hole 1 g. Then, as the plunger 2 approaches the lower starting point where the volume of the pressurizing chamber 11 is most expanded, the area communicating with the pressurizing chamber of the supply communication hole 1g increases.

A part of the fuel in the suction valve chamber 30 flows into the pressurizing chamber 11 through the supply communication hole 1g and not through the second chamber 1b (relief valve chamber). As a result, a passage (fuel passage) through which the fuel supplied to the pressurizing chamber 11 passes can be secured, and the fuel in the suction valve chamber 30 can be easily supplied to the pressurizing chamber 11. The opening area of the supply communication hole 1g is set to be equal to or larger than the opening area of the suction passage 1d.

In the present embodiment, the suction passage 1d (communication hole) and the supply communication hole 1g are formed in a circular shape. However, the communication hole and the communication hole for supply according to the present invention are not limited to a circle, and can be appropriately set to various shapes such as a polygon and an ellipse. Further, in the present embodiment, the insertion portion 42b is formed in a columnar shape. However, as long as the insertion portion according to the present invention is arranged inside the relief spring 41 in the radial direction, it can be appropriately set to various shapes such as a prismatic shape and other rod shapes.

[Operation of high-pressure fuel pump]
Next, the operation of the high-pressure fuel pump according to the present embodiment will be described with reference to FIGS. 2 and 4.

In FIG. 2, when the plunger 2 is lowered and the electromagnetic suction valve mechanism 3 is opened, fuel flows into the pressurizing chamber 11 from the suction passage 1d. Hereinafter, the process in which the plunger 2 descends is referred to as an inhalation process. On the other hand, when the plunger 2 is raised and the electromagnetic suction valve mechanism 3 is closed, the fuel in the pressurizing chamber 11 is boosted and passes through the discharge valve mechanism 8 (see FIG. 4) to pass through the common rail 106 (see FIG. 4). It is pumped to (see Fig. 1). Hereinafter, the process of raising the plunger 2 is referred to as an ascending process.

As described above, if the electromagnetic suction valve mechanism 3 is closed during the ascending step, the fuel sucked into the pressurizing chamber 11 during the suction stroke is pressurized and discharged to the common rail 106 side. On the other hand, if the electromagnetic suction valve mechanism 3 is opened during the ascending step, the fuel in the pressurizing chamber 11 is pushed back to the suction passage 1d side and is not discharged to the common rail 106 side. As described above, the discharge of fuel by the high-pressure fuel supply pump 100 is operated by opening and closing the electromagnetic suction valve mechanism 3. Then, the opening and closing of the electromagnetic suction valve mechanism 3 is controlled by the ECU 101.

In the suction stroke, the volume of the pressurizing chamber 11 increases, and the fuel pressure in the pressurizing chamber 11 decreases. As a result, the fluid differential pressure between the suction port 31b and the pressurizing chamber 11 (hereinafter referred to as "fluid differential pressure before and after the valve portion 32") becomes small. When the urging force of the rod urging spring 34 becomes larger than the fluid differential pressure before and after the valve portion 32, the rod 33 moves in the valve opening direction, and the valve portion 32 separates from the seating portion 31a of the suction valve seat 31. , The electromagnetic suction valve mechanism 3 is opened.

When the electromagnetic suction valve mechanism 3 is opened, the fuel in the suction port 31b passes between the valve portion 32 and the seating portion 31a, passes through a plurality of fuel passage holes (not shown) of the stopper 37, and is a suction passage. It flows into the pressurizing chamber 11 from 1d or 1 g of the supply communication hole. In the valve open state of the electromagnetic suction valve mechanism 3, the valve portion 32 comes into contact with the stopper 37, so that the position of the valve portion 32 in the valve opening direction is restricted. The gap existing between the valve portion 32 and the seating portion 31a in the valve open state of the electromagnetic suction valve mechanism 3 is the movable range of the valve portion 32, and this is the valve opening stroke.

After completing the inhalation process, the process moves to the ascending process. At this time, the electromagnetic coil 35 remains in a non-energized state, and no magnetic attraction force acts between the anchor 36 and the magnetic core 39. Then, in the valve portion 32, the urging force in the valve opening direction according to the difference between the urging forces of the rod urging spring 34 and the valve urging spring 38 and the fuel flow back from the pressurizing chamber 11 to the low pressure fuel flow path 10a. A force that presses in the valve closing direction due to the fluid force generated at the time of operation works.

In this state, in order for the electromagnetic suction valve mechanism 3 to maintain the valve open state, the difference in urging force between the rod urging spring 34 and the valve urging spring 38 is set to be larger than the fluid force. The volume of the pressurizing chamber 11 decreases as the plunger 2 rises. Therefore, the fuel sucked into the pressurizing chamber 11 passes between the valve portion 32 and the seating portion 31a again and is returned to the suction port 31b, so that the pressure inside the pressurizing chamber 11 rises. There is no. This process is called the return process.

In the return step, when a control signal from the ECU 101 (see FIG. 1) is applied to the electromagnetic suction valve mechanism 3, a current flows through the electromagnetic coil 35 via the terminal member 40. When a current flows through the electromagnetic coil 35, a magnetic attraction force acts between the magnetic core 39 and the anchor 36, and the anchor 36 (rod 33) is attracted to the magnetic core 39. As a result, the anchor 36 (rod 33) moves in the valve closing direction (direction away from the valve portion 32) against the urging force of the rod urging spring 34.

When the anchor 36 (rod 33) moves in the valve closing direction, the valve portion 32 is released from the urging force in the valve opening direction, and the urging force by the valve urging spring 38 and the flow due to the fuel flowing into the suction passage 10b. It moves in the valve closing direction due to physical strength. Then, when the valve portion 32 comes into contact with the seating portion 31a of the suction valve seat 31 (the valve portion 32 is seated on the seating portion 31a), the electromagnetic suction valve mechanism 3 is closed.

After the electromagnetic suction valve mechanism 3 is closed, the fuel in the pressurizing chamber 11 is boosted as the plunger 2 rises, and when the pressure exceeds a predetermined pressure, the fuel passes through the discharge valve mechanism 8 and passes through the common rail 106 (FIG. 1). See). This process is called a discharge process. That is, the ascending stroke from the lower start point to the upper start point of the plunger 2 consists of a return stroke and a discharge stroke. Then, by controlling the energization timing of the electromagnetic suction valve mechanism 3 to the electromagnetic coil 35, the amount of high-pressure fuel discharged can be controlled.

If the timing of energizing the electromagnetic coil 35 is earlier, the ratio of the return stroke during the ascending stroke becomes smaller and the ratio of the discharge stroke becomes larger. As a result, less fuel is returned to the suction passage 10b, and more fuel is discharged at high pressure. On the other hand, if the timing of energizing the electromagnetic coil 35 is delayed, the ratio of the return stroke during the ascending stroke increases and the ratio of the discharge stroke decreases. As a result, more fuel is returned to the suction passage 10b, and less fuel is discharged at high pressure. By controlling the energization timing of the electromagnetic coil 35 in this way, the amount of fuel discharged at high pressure can be controlled to the amount required by the engine (internal combustion engine).

2. Summary As described above, the high-pressure fuel supply pump 100 (fuel pump) according to the above-described embodiment has a pump body 1 (body) having a pressurizing chamber 11 (pressurizing chamber) and a pressurizing chamber 11 The electromagnetic suction valve mechanism 3 (suction valve mechanism) arranged in the suction valve chamber 30 (suction valve chamber) provided on the upstream side of the pressure chamber 11 and the discharge valve chamber 80 (discharge valve) provided on the downstream side of the pressurizing chamber 11. It is provided with a discharge valve mechanism 8 arranged in a chamber) and a relief valve mechanism 4 (relief valve mechanism) arranged in a second chamber 1b (relief valve chamber) provided on the downstream side of the pressurizing chamber 11. The discharge valve mechanism 8 discharges fuel to the pressurizing chamber 11. The relief valve mechanism 4 opens the valve when the difference between the pressure in the discharge valve chamber 80 and the pressure in the second chamber 1b exceeds a set value, and returns the fuel to the pressurizing chamber 11.

The relief valve mechanism 4 includes a relief valve 43 (relief valve) that opens and closes a flow path from the discharge valve chamber 80 to the second chamber 1b, a relief valve holder 42 (relief valve holder) that engages with the relief valve 43, and a relief valve. It has a coil-shaped relief spring 41 (relief spring) that urges the valve holder 42 toward the discharge valve chamber 80. A suction passage 1d (communication hole) is formed between the discharge valve chamber 80 and the second chamber 1b, and the relief valve holder 42 has an insertion portion 42b (insertion) inserted inside the relief spring 41 in the radial direction. Part). The tip of the insertion portion 42b is arranged near the end of the relief spring 41 on the side opposite to the insertion side of the insertion portion 42b or in the suction passage 1d, and the opening area of the suction passage 1d is larger than the area of the tip of the insertion portion 42b. big. The tip of the insertion portion 42b is arranged in the suction passage 1d.

Since the tip of the insertion portion 42b reaches the vicinity of the end (seat surface of the spring) on the side opposite to the insertion side of the insertion portion 42b in the relief spring 41, the dead space of the second chamber 1b communicating with the pressurizing chamber 11 is inserted into the insertion portion. It can be filled with 42b. As a result, the compression efficiency of the pressurizing chamber 11 including the second chamber 1b can be improved as compared with the case where the insertion portion 42b is not provided. However, by filling the dead space of the second chamber 1b with the insertion portion 42b, the inflow of fuel passing through the suction passage 1d into the pressurizing chamber 11 is blocked by the insertion portion 42b.

Therefore, in the present embodiment, the opening area of the suction passage 1d is made larger than the area of the tip of the insertion portion 42b. Thereby, a passage (fuel passage) through which the fuel passing through the suction passage 1d passes can be secured around the insertion portion 42b. As a result, the inflow of fuel passing through the suction passage 1d into the pressurizing chamber 11 can be prevented from being blocked by the insertion portion 42b. Therefore, in the present embodiment, the dead volume of the relief valve mechanism 4 can be reduced, and the passage of the fuel that has passed through the intake passage 1d to the pressurizing chamber 11 can be secured.

Further, in the high-pressure fuel supply pump 100 (fuel pump) according to the above-described embodiment, the tip of the insertion portion 42b (insertion portion) and the suction passage 1d (communication hole) are formed in a circular shape, and the suction passage 1d has a circular shape. The diameter is larger than the diameter of the tip of the insertion portion 42b. It is possible to secure a fuel passage around the insertion portion 42b while efficiently reducing the dead volume generated inside the relief spring 41 in the radial direction.

Further, in the high-pressure fuel supply pump 100 (fuel pump) according to the above-described embodiment, the central axis of the insertion portion 42b (insertion portion) is the suction passage 1d (communication hole) in the operating direction of the relief valve 43 (relief valve). ) Overlaps the central axis. As a result, the fuel passage formed around the insertion portion 42b can be made into an annular shape, and the fuel can flow smoothly.

Further, in the high-pressure fuel supply pump 100 (fuel pump) according to the above-described embodiment, the tip of the insertion portion 42b (insertion portion) is formed in a flat surface. This makes it possible to facilitate the processing of the insertion portion 42b and the relief valve holder 42 (relief valve holder).

Further, in the high-pressure fuel supply pump 100 (fuel pump) according to the above-described embodiment, one end of the relief spring 41 (relief spring) is around the suction passage 1d (communication hole) in the second chamber 1b (relief valve chamber). Contact. As a result, the relief spring 41 can be prevented from hindering the progress of the fuel that has passed through the suction passage 1d.

Further, the high-pressure fuel supply pump 100 (fuel pump) according to the above-described embodiment is the operation direction of the relief valve 43 (relief valve) of the relief valve mechanism 4 (relief valve mechanism) and the center of the suction passage 1d (communication hole). The axial direction is the same as the operating direction of the valve portion 32 (suction valve) in the electromagnetic suction valve mechanism 3 (suction valve mechanism). As a result, the fuel opened and sucked by the operation of the valve portion 32 can pass through the suction passage 1d without changing its traveling direction, and the fuel is efficiently flowed into the pressurizing chamber 11 (sucked). )be able to.

Further, in the high-pressure fuel supply pump 100 (fuel pump) according to the above-described embodiment, the insertion portion 42b (insertion portion) of the relief valve holder 42 (relief valve holder) has a tapered portion whose outer diameter decreases toward the tip. It has 42c (tapered portion). Thereby, a passage (fuel passage) through which the fuel passing through the suction passage 1d passes can be secured around the insertion portion 42b.

Further, in the high-pressure fuel supply pump 100 (fuel pump) according to the above-described embodiment, the tapered portion 42c (tapered portion) is larger than the portion of the relief spring 41 (relief spring) in which a gap is formed in adjacent rings. It starts from the relief valve 43 (relief valve) side. As a result, the fuel between the relief spring 41 and the tapered portion 42c easily travels outward in the radial direction of the relief spring 41 from between the adjacent rings in the relief spring 41. As a result, the fuel can be efficiently sucked into the pressurizing chamber 11.

Further, the high-pressure fuel supply pump 100 (fuel pump) according to the above-described embodiment is provided on the pump body 1 (body) so as to be reciprocating, and the plunger 2 increases or decreases the volume of the pressurizing chamber 11 (pressurizing chamber). Equipped with (plunger). The operating direction of the relief valve 43 (relief valve) is orthogonal to the operating direction of the plunger 2, and the tip of the insertion portion 42b (insertion portion) in the relief valve holder 42 (relief valve holder) is closer to the side surface of the plunger 2. It is arranged on the suction passage 1d (communication hole) side. As a result, the dead volume of the relief valve mechanism 4 can be reduced.

Further, in the high-pressure fuel supply pump 100 (fuel pump) according to the above-described embodiment, the pump body 1 (body) does not pass from the suction valve chamber 30 (suction valve chamber) to the second chamber 1b (relief valve chamber). It also has a supply communication hole 1 g (supply communication hole) for supplying fuel to the pressurizing chamber 11 (pressurizing chamber). As a result, fuel can be efficiently sucked from the suction valve chamber 30 to the pressurizing chamber 11.

Further, the high-pressure fuel supply pump 100 (fuel pump) according to the above-described embodiment is provided on the pump body 1 (body) so as to be reciprocating, and the plunger 2 increases or decreases the volume of the pressurizing chamber 11 (pressurizing chamber). Equipped with (plunger). Then, at least a part of the supply communication hole 1 g (supply communication hole) overlaps the operating range of the plunger 2 in the operating direction of the relief valve 43 (relief valve). As a result, the pressure chamber 11 can be made smaller than the case where the supply communication hole 1 g does not overlap the operating range of the plunger 2. As a result, the volume of the pressurizing chamber 11 can be reduced, and the compression efficiency of the pressurizing chamber 11 can be improved.

The embodiment of the fuel pump of the present invention has been described above, including its action and effect. However, the fuel pump of the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the gist of the invention described in the claims. Further, the above-described embodiment has been described in detail in order to explain the present invention in an easy-to-understand manner, and is not necessarily limited to the one including all the described configurations.

For example, in the above-described embodiment, an example in which one suction passage 1d (communication hole) is provided has been described. However, two or more communication holes according to the present invention may be provided. In this case, the tip of the insertion portion 42b may be opposed to any one of the plurality of communication holes, or the tip of the insertion portion 42b may be inserted into any one of the plurality of communication holes.

Further, in the above-described embodiment, the tip of the insertion portion 42b is in the vicinity of the end portion of the relief spring 41 opposite to the insertion side of the insertion portion 42b (seat surface of the relief spring 41) or in the suction passage 1d (communication hole). An example of placement has been described. However, the insertion portion according to the present invention may penetrate the suction passage 1d (communication hole). In this case, the insertion portion should not interfere with the electromagnetic suction valve mechanism 3. In addition, the suction passage 1d (communication hole) is not sealed by the insertion portion.

Further, in the above-described embodiment, the central axis of the suction passage 1d (communication hole) coincides with the central axis of the insertion portion 42b in the relief valve holder 42. However, in the fuel pump according to the present invention, it is sufficient that the communication hole and the relief valve chamber communicate with each other, and the central axis of the communication hole and the central axis of the insertion portion do not have to coincide with each other. Further, in the fuel pump according to the present invention, the central axis of the communication hole and the central axis of the relief valve chamber do not have to coincide with each other.

Further, in the above-described embodiment, the tip of the insertion portion 42b in the relief valve holder 42 is formed in a flat surface. However, the tip of the insertion portion according to the fuel pump according to the present invention may be formed on a curved surface or a spherical surface. Further, the insertion portion of the fuel pump according to the present invention may have a conical or pyramidal tip. In these cases, the opening area of the suction passage 1d (communication hole) may be larger than the area of the shape of the tip of the insertion portion when viewed from the central axis direction.

1 ... Pump body, 1a ... 1st chamber, 1b ... 2nd chamber (relief valve chamber), 1c ... 3rd chamber, 1d ... Suction passage (communication hole), 1e ... Communication hole, 1f ... Tapered surface, 1g ... Supply Communication hole, 2 ... Plunger, 3 ... Electromagnetic suction valve mechanism, 4 ... Relief valve mechanism, 5 ... Suction joint, 6 ... Cylinder, 8 ... Discharge valve mechanism, 9 ... Pressure pulsation reduction mechanism, 10 ... Low pressure fuel chamber, 11 ... Pressurizing chamber, 12 ... Discharge joint, 12a ... Discharge passage, 12b ... Fuel discharge port, 12c ... Welding part, 30 ... Suction valve chamber 30, 41 ... Relief spring, 42 ... Relief valve holder, 42a ... Contact part, 42b ... Insertion part, 42c ... Tapered part, 43 ... Relief valve, 44 ... Seat member, 80 ... Discharge valve chamber, 100 ... High pressure fuel supply pump, 101 ... ECU, 102 ... Feed pump, 103 ... Fuel tank, 104 ... Low pressure Piping, 105 ... Fuel pressure sensor, 106 ... Common rail, 107 ... Injector

Claims (11)

A body with a pressurizing chamber and
A suction valve mechanism arranged in a suction valve chamber provided on the upstream side of the pressurizing chamber and discharging fuel to the pressurizing chamber, and a suction valve mechanism.
A discharge valve mechanism arranged in a discharge valve chamber provided on the downstream side of the pressurizing chamber, and a discharge valve mechanism.
It is arranged in a relief valve chamber provided on the downstream side of the pressurizing chamber, and is opened when the difference between the pressure of the discharge valve chamber and the pressure of the relief valve chamber exceeds a set value, and the pressurizing chamber is opened. With a relief valve mechanism that returns fuel to
The relief valve mechanism is
A relief valve that opens and closes the flow path from the discharge valve chamber to the relief valve chamber,
A relief valve holder that engages with the relief valve,
It has a coiled relief spring that urges the relief valve holder toward the discharge valve chamber side.
A communication hole is formed between the suction valve chamber and the relief valve chamber.
The relief valve holder has an insertion portion that is inserted inside the relief spring in the radial direction.
The tip of the insertion portion is arranged near the end of the relief spring on the side opposite to the insertion side into which the insertion portion is inserted.
A fuel pump in which the opening area of the communication hole is larger than the area of the tip of the insertion portion. The tip of the insertion portion and the communication hole are formed in a circular shape.
The fuel pump according to claim 1, wherein the diameter of the communication hole is larger than the diameter of the tip of the insertion portion. The fuel pump according to claim 2, wherein the central axis of the insertion portion overlaps the central axis of the communication hole in the operating direction of the relief valve of the relief valve mechanism. The fuel pump according to claim 1, wherein the tip of the insertion portion is formed in a flat surface. The fuel pump according to claim 1, wherein one end of the relief spring abuts around the communication hole in the relief valve chamber. The fuel pump according to claim 1, wherein the operating direction of the relief valve of the relief valve mechanism and the central axis direction of the communication hole are the same as the operating direction of the suction valve in the suction valve mechanism. The fuel pump according to claim 1, wherein the insertion portion of the relief valve holder has a tapered portion whose outer diameter decreases toward the tip end. The fuel pump according to claim 7, wherein the tapered portion starts from the relief valve side of the portion of the relief spring in which a gap is formed in adjacent rings. A plunger is provided on the body so as to be reciprocating and the volume of the pressurizing chamber is increased or decreased.
The operating direction of the relief valve is orthogonal to the operating direction of the plunger.
The fuel pump according to claim 1, wherein the tip of the insertion portion in the relief valve holder is arranged on the communication hole side with respect to the side surface of the plunger. The fuel pump according to claim 1, wherein the body has a supply communication hole for supplying fuel from the suction valve chamber to the pressurizing chamber without passing through the relief valve chamber. A plunger is provided on the body so as to be reciprocating and the volume of the pressurizing chamber is increased or decreased.
The fuel pump according to claim 10, wherein at least a part of the supply communication holes overlaps the operating range of the plunger in the operating direction of the relief valve.

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