JP7385750B2 - Fuel pump - Google Patents

Description

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

The fuel pump is described in Patent Document 1, for example. The high-pressure fuel supply pump described in Patent Document 1 includes a housing, a suction valve, a discharge valve, and a relief valve. The housing has a cylinder that is a stepped cylindrical space that accommodates a cylinder liner that slidably holds the plunger and forms a pressurizing chamber. The suction valve opens when no current is supplied to the electromagnetic solenoid, and opens when current is supplied to the electromagnetic solenoid to suck fuel into the pressurizing chamber.

The discharge valve is assembled into a discharge valve accommodating portion of the housing, and the discharge valve accommodating portion communicates with the pressurizing chamber via a fuel discharge hole. High-pressure fuel pressurized in the pressurization 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 pumped to the pressure accumulator.

Further, the relief valve is assembled into a relief valve accommodating portion of the housing, and the relief valve accommodating portion communicates with a high pressure region downstream of the discharge valve and communicates with the pressurizing chamber via a communication path. 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.

Special table 2018-523778 publication

However, the high-pressure fuel supply pump described in Patent Document 1 is provided with a communication passage that communicates the discharge valve and the pressurizing chamber, and a communication passage that communicates the relief valve and the pressurization chamber, respectively. It was getting worse. Therefore, the high-pressure fuel supply pump described in Patent Document 1 increases the dead volume when filling the pressurizing chamber with fuel, resulting in a decrease in the volumetric efficiency of the pump.

An object of the present invention is to provide a fuel pump that takes the above-mentioned problems into consideration and can improve volumetric efficiency.

In order to solve the above problems and achieve the objects of the present invention, the fuel pump of the present invention includes a pump body provided with a pressurizing chamber, a plunger that reciprocates in the pressurizing chamber, and a pump body that discharges fuel from the pressurizing chamber. It includes a discharge valve mechanism for discharging into the chamber and a relief valve mechanism. The relief valve mechanism opens when the difference between the fuel pressure in the discharge chamber and the fuel pressure in the pressurizing chamber exceeds a set value, and returns the fuel in the discharge chamber to the pressurizing chamber. When viewed from the axial direction of the plunger, the discharge valve mechanism and the relief valve mechanism are arranged such that the moving directions of their valves intersect with each other. The relief valve mechanism is arranged at a position overlapping the pressurizing chamber in the axial direction of the plunger. The discharge valve inlet passage of the discharge valve mechanism is in direct communication with the relief chamber in which the relief valve mechanism is arranged and the pressurization chamber.

According to the fuel pump having the above configuration, it is possible to improve the volumetric efficiency.
Note that problems, configurations, and effects other than those described above will be made clear by the description of the embodiments below.

1 is an overall configuration diagram of a fuel supply system using a high-pressure fuel supply pump according to a first embodiment of the present invention. FIG. 1 is a vertical cross-sectional view (part 1) of the high-pressure fuel supply pump according to the first embodiment of the present invention. FIG. 2 is a vertical cross-sectional view (Part 2) of the high-pressure fuel supply pump according to the first embodiment of the present invention. FIG. 2 is a horizontal cross-sectional view of the high-pressure fuel supply pump according to the first embodiment of the present invention, seen from above. FIG. 1 is a partially cutaway perspective sectional view of a high-pressure fuel supply pump according to a first embodiment of the present invention. FIG. 3 is a longitudinal cross-sectional view of a high-pressure fuel supply pump according to a second embodiment of the present invention. FIG. 3 is a partially cutaway perspective sectional view of a high-pressure fuel supply pump according to a second embodiment of the present invention.

1. First Embodiment A high-pressure fuel supply pump according to a first embodiment of the present invention will be described below. Note that common members in each figure are given the same reference numerals.

[Fuel supply system]
A fuel supply system using a high-pressure fuel supply pump (fuel pump) according to a first 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 this 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, and a common rail 106.
and a plurality of injectors 107. The parts of the high-pressure fuel supply pump 100 are integrated into the pump body 1.

Fuel in the fuel tank 103 is pumped up by a feed pump 102 that is driven based on a signal from the ECU 101. The pumped fuel is pressurized to an appropriate pressure by a pressure regulator (not shown), and is sent to the low-pressure fuel inlet 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 attached to the common rail 106. The plurality of injectors 107 are installed 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 this embodiment is a so-called direct injection engine system in which the injector 107 injects fuel directly into the cylinder of the engine.

Fuel pressure sensor 105 outputs detected pressure data to ECU 101. The ECU 101 determines an appropriate amount of injected fuel (target injection fuel length) and appropriate fuel pressure (target (fuel pressure), etc.

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

The high-pressure fuel supply pump 100 includes a pressure pulsation reduction mechanism 9, an electromagnetic suction valve mechanism 3 that is a variable capacity mechanism, a relief valve mechanism 4 (see FIG. 2), and a discharge valve mechanism 8. Fuel flowing from the low-pressure fuel intake port 51 reaches the intake port 31b of the electromagnetic intake valve mechanism 3 via the pressure pulsation reduction mechanism 9 and the intake 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 able to reciprocate. The plunger 2 reciprocates as power is transmitted by a cam (not shown) of the engine.

In the pressurizing chamber 11, fuel is sucked in from the electromagnetic intake valve mechanism 3 during the downward stroke of the plunger 2, and the fuel is pressurized during the upward stroke. When the fuel pressure in the pressurizing chamber 11 exceeds a predetermined value, the discharge valve mechanism 8 opens, and high-pressure fuel is force-fed to the common rail 106 via the discharge passage 12a. The discharge of fuel by the high-pressure fuel supply pump 100 is controlled by opening and closing the electromagnetic intake valve mechanism 3. Opening and closing of the electromagnetic intake 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 explained using FIGS. 2 to 5.
FIG. 2 is a vertical cross-sectional view (part 1) of the high-pressure fuel supply pump 100 taken in a cross section perpendicular to the horizontal direction. FIG. 3 is a vertical cross-sectional view (part 2) of the high-pressure fuel supply pump 100 taken in a cross section perpendicular to the horizontal direction. FIG. 4 is a horizontal cross-sectional view of the high-pressure fuel supply pump 100 taken along a cross section perpendicular to the vertical direction. Further, FIG. 5 is a partially cutaway perspective sectional view of the high-pressure fuel supply pump 100.

As shown in FIGS. 2 to 5, the pump body 1 of the high-pressure fuel supply pump 100 is formed into a substantially cylindrical 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.

The first chamber 1a is a columnar space provided in the pump body 1. The centerline 1A of the first chamber 1a coincides with the centerline of the pump body 1. One end of the plunger 2 is inserted into the first chamber 1a. The plunger 2 reciprocates within the first chamber 1a. The first chamber 1a and one end of the plunger 2 form a pressurizing chamber 11.

The second chamber 1b is a cylindrical 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 mechanism 4 is arranged in this second chamber 1b. Therefore, the second chamber 1b represents a specific example of the relief chamber according to the present invention. Note that the diameter of the second chamber 1b is smaller than the diameter of the first chamber 1a.

Further, the first chamber 1a and the second chamber 1b communicate with each other through a circular communication hole 1e. The diameter of the communication hole 1e is the same as the diameter of the first chamber 1a. 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. The center line of the communication hole 1e coincides with the center line of the pump body 1. Further, the center line of the communication hole 1e is perpendicular to the center line of the second chamber 1b. Moreover, as shown in FIG. 3, the diameter of the communication hole 1e is larger than the diameter of the second chamber 1b.

The third chamber 1c is a columnar space provided in the pump body 1. The third chamber 1c 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. The diameter of the third chamber 1c is larger than the diameter of the first chamber 1a. A cylinder 6 that guides the reciprocating movement of the plunger 2 is arranged in the third chamber 1c.

The cylinder 6 is formed into a cylindrical shape, and its outer peripheral side is press-fitted into the third chamber 1c of the pump body 1. One end of the cylinder 6 is in contact with the top surface of the third chamber 1c (the step between the first chamber 1a and the third chamber 1c). The plunger 2 is in slidable contact with the inner peripheral surface of the cylinder 6. The plunger 2 is guided by the cylinder 6 and reciprocates in the axial direction.

An O-ring 93, which is a specific example of a seat member, is interposed between the fuel pump mounting portion (not shown) and the pump body 1. This O-ring 93 prevents engine oil from leaking to the outside of the engine (internal combustion engine) through between the fuel pump mounting portion and the pump body 1.

A tappet (not shown) is provided at the lower end of the plunger 2. The tappet converts the rotational motion of a cam attached to the camshaft of the engine into vertical motion and transmits it to the plunger 2. The plunger 2 is urged toward a cam (not shown) by a spring 16 via a retainer 15. The tappet reciprocates as the cam rotates. The plunger 2 reciprocates together with the tappet, resulting in a change in 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 into a cylindrical shape into which the plunger 2 is inserted, and has a subchamber 17a at the upper end on the cylinder 6 side. Further, the seal holder 17 holds a plunger seal 18 at a lower end portion on the retainer 15 side.

The plunger seal 18 is in slidable contact with the outer periphery of the plunger 2. The plunger seal 18 seals the fuel in the auxiliary chamber 17a. Thereby, when the plunger 2 reciprocates, the fuel in the auxiliary chamber 17a does not flow into the engine. Further, the plunger seal 18 prevents lubricating oil (including engine oil) that lubricates sliding parts within the engine from flowing into the inside of the pump body 1.

In FIGS. 2 and 3, the plunger 2 reciprocates in the vertical direction. When the plunger 2 descends, the volume of the pressurizing chamber 11 increases, and when the plunger 2 ascends, the volume of the pressurizing chamber 11 decreases. 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 subchamber 17a. Therefore, the volume of the subchamber 17a increases or decreases as the plunger 2 reciprocates.

The auxiliary chamber 17a communicates with the low pressure fuel chamber 10 through a fuel passage 10c (see FIG. 3). When the plunger 2 descends, fuel flows from the sub-chamber 17a to the low-pressure fuel chamber 10, and when the plunger 2 rises, fuel flows from the low-pressure fuel chamber 10 to the sub-chamber 17a. Thereby, the fuel flow rate in and out of the pump during the suction stroke or return stroke of the high-pressure fuel supply pump 100 can be reduced, and pressure pulsations occurring inside the high-pressure fuel supply pump 100 can be reduced.

As shown in FIG. 4, a suction joint 5 is attached to a side surface of the pump body 1. The intake joint 5 is connected to a low pressure pipe 104 through which fuel supplied from a fuel tank 103 (see FIG. 1) passes. Fuel in the fuel tank 103 is supplied into 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 passage 52 passes through a 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 substances present in the fuel and prevents foreign substances from entering the high-pressure fuel supply pump 100.

As shown in FIGS. 2 and 3, a low pressure fuel chamber 10 is provided in the upper part of the pump body 1 of the high pressure fuel supply pump 100. The low pressure fuel chamber 10 is provided with a low pressure fuel passage 10a and an intake passage 10b (see FIG. 2). A pressure pulsation reduction mechanism 9 is provided in the low pressure fuel flow path 10a. When the fuel that has flowed into the pressurizing chamber 11 passes through the electromagnetic suction valve mechanism 3 in the open state again and returns to the suction passage 10b, pressure pulsations occur in the low-pressure fuel chamber 10. The pressure pulsation reduction mechanism 9 reduces pressure pulsations generated within the high-pressure fuel supply pump 100 from spreading to the low-pressure piping 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 at their outer peripheries, and an inert gas such as argon is injected into the inside thereof. The metal diaphragm damper of the pressure pulsation reduction mechanism 9 absorbs or reduces pressure pulsations 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 that has passed through the low-pressure fuel passage 10a passes through the suction passage 10b to the suction port 31b of the electromagnetic suction valve mechanism 3. 31b is reached.

As shown in FIGS. 2 and 4, the electromagnetic suction valve mechanism 3 is inserted into a side hole formed in the pump body 1. The electromagnetic suction valve mechanism 3 includes a suction valve seat 31 press-fitted into a side hole formed in the pump body 1, a valve portion 32, a rod 33, a rod biasing spring 34, an electromagnetic coil 35, and an anchor 36. have.

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

A stopper 37 facing the seating portion 31a of the suction valve seat 31 is arranged in a side hole formed in the pump body 1. The valve portion 32 is arranged between the stopper 37 and the seating portion 31a. Further, a valve biasing spring 38 is interposed between the stopper 37 and the valve portion 32. The valve biasing spring 38 biases the valve portion 32 toward the seating portion 31a.

The valve portion 32 closes the communication portion between the suction port 31b and the pressurizing chamber 11 by contacting the seating portion 31a. As a result, the electromagnetic intake valve mechanism 3 enters the closed state. On the other hand, the valve portion 32 opens the communication portion between the suction port 31b and the pressurizing chamber 11 by coming into contact with the stopper 37. As a result, the electromagnetic suction valve mechanism 3 becomes open.

The rod 33 passes through a cylindrical hole in the suction valve seat 31. One end of the rod 33 is in contact with the valve portion 32. The rod biasing spring 34 biases the valve portion 32 via the rod 33 in the valve opening direction, which is the stopper 37 side. One end of the rod biasing spring 34 is engaged with the other end of the rod 33. The other end of the rod biasing spring 34 is engaged with a magnetic core 39 arranged to surround the rod biasing spring 34 .

Anchor 36 faces the end surface of magnetic core 39 . Further, the anchor 36 is engaged with a flange provided at the intermediate 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 where no current flows through the electromagnetic coil 35, the rod 33 is biased in the valve opening direction by the biasing force of the rod biasing spring 34. Thereby, the rod 33 presses the valve portion 32 in the valve opening direction. As a result, the valve portion 32 moves away from the seating portion 31a and comes into contact with the stopper 37, and the electromagnetic suction valve mechanism 3 is in an open state. That is, the electromagnetic suction valve mechanism 3 is of a normally open type that opens in a non-energized state.

When the electromagnetic suction valve mechanism 3 is in the open state, 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) in the stopper 37, and the suction passage 1d. It flows into the pressurizing chamber 11. When the electromagnetic suction valve mechanism 3 is in the open state, 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 regulated. When the electromagnetic suction valve mechanism 3 is in the open state, the gap that exists between the valve portion 32 and the seating portion 31a is the movable range of the valve portion 32. That is, when the electromagnetic intake valve mechanism 3 is in the open state, the gap existing between the valve portion 32 and the seating portion 31a corresponds to a valve opening stroke.

When current flows through the electromagnetic coil 35, the anchor 36 is drawn in the valve closing direction by the magnetic attraction force of the magnetic core 39. As a result, the anchor 36 moves against the biasing force of the rod biasing spring 34 and comes into contact with the magnetic core 39 . When the anchor 36 moves in the valve closing direction toward the magnetic core 39, the rod 33 moves together with the anchor 36. As a result, the valve portion 32 is released from the biasing force in the valve-opening direction and moves in the valve-closing direction by the biasing force of the valve biasing spring 38. 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 enters the closed state.

As shown in FIGS. 3 and 4, the discharge valve mechanism 8 is connected to the outlet side (downstream side) of the pressurizing chamber 11. The discharge valve mechanism 8 includes a discharge valve seat 81 communicating with the pressurizing chamber 11, a valve portion 82 that comes into contact with and separates from the discharge valve seat 81, and a discharge valve spring 83 that biases the valve portion 82 toward the discharge valve seat 81. , a discharge valve stopper 84 that determines the stroke (movement distance) of the valve portion 82.

The discharge valve seat 81 is formed into a substantially cylindrical shape. The discharge valve seat 81 has a seat passage 8a which is a shaft hole. The seat passage 8a forms a passage on the pressure chamber 11 side in the discharge valve mechanism 8. The pump body 1 is provided with a discharge valve inlet passage 1f that communicates the pressurizing chamber 11 and the seat passage 8a. The discharge valve inlet passage 1f communicates not only with the pressurizing chamber 11 but also with the second chamber 1b (relief chamber).

The valve portion 82 faces an end surface of the discharge valve seat 81 on the side opposite to the pressurizing chamber 11 side. The valve portion 82 is urged toward the discharge valve seat 81 by a discharge valve spring 83 and is pressed against the discharge valve seat 81 . When the valve portion 82 separates from the discharge valve seat 81, fuel in the pressurizing chamber 11 can pass between the valve portion 82 and the discharge valve seat 81. This causes the discharge valve mechanism 8 to be in the open state.

Further, the discharge valve mechanism 8 includes a plug 85 that blocks 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 a welding portion 86. As shown in FIG. 4, the discharge valve mechanism 8 communicates with a discharge chamber 87 that is opened and closed by a valve portion 82. The discharge chamber 87 is formed in the pump body 1.

The pump body 1 is provided with a side hole that communicates with the second chamber 1b (see FIG. 2), and a discharge joint 12 is inserted into the side hole. The discharge joint 12 has the above-mentioned discharge passage 12a communicating with the side hole of the pump body 1 and the discharge chamber 87, and a 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. Note that the discharge joint 12 is fixed to the pump body 1 by welding through a welded portion 12c.

When there is no fuel pressure difference (fuel pressure difference) between the pressurizing chamber 11 and the discharge chamber 87, the valve portion 82 is pressed against the discharge valve seat 81 by the urging force of the discharge valve spring 83. As a result, the discharge valve mechanism 8 is in a closed state. When the fuel pressure in the pressurizing chamber 11 becomes greater than the fuel pressure in the discharge chamber 87, the valve portion 82 moves against the biasing force of the discharge valve spring 83. As a result, the discharge valve mechanism 8 becomes open.

The moving direction of the valve part 82 in the discharge valve mechanism 8 is orthogonal to the direction in which the plunger 2 reciprocates. Note that the direction in which the plunger 2 reciprocates corresponds to the first direction according to the present invention. Further, the moving direction of the valve portion 82 in the discharge valve mechanism 8 corresponds to the third direction according to the present invention.

When the discharge valve mechanism 8 enters the closed state, the (high pressure) fuel in the pressurizing chamber 11 passes through the discharge valve mechanism 8 and reaches the discharge chamber 87 . The fuel that has reached the discharge chamber 87 is then 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 restricts the direction of fuel flow.

If some problem occurs in the common rail 106 or a member beyond it, and the pressure in the common rail 106 becomes high beyond a predetermined pressure, the relief valve mechanism 4 shown in FIG. 2 is activated, and the fuel in the discharge passage 12a is activated. is returned to the pressurizing chamber 11. As shown in FIG. 5, the relief valve mechanism 4 is arranged at a higher position than the discharge valve mechanism 8 (see FIG. 5) in the direction in which the plunger 2 reciprocates (vertical direction).

As shown in FIG. 2, the relief valve mechanism 4 includes a relief spring 41, a relief valve holder 42, a valve portion 43, and a seat member 44. This relief valve mechanism 4 is inserted through the discharge joint 12 and arranged in the second chamber 1b. The relief spring 41 has one end in contact with the pump body 1 (one end of the second chamber 1b), and the other end in contact with the relief valve holder 42. The relief valve holder 42 is engaged with the valve portion 43. The biasing force of the relief spring 41 acts on the valve portion 43 via the relief valve holder 42.

The valve portion 43 is pressed by the biasing force of the relief spring 41 and closes the fuel passage of the seat member 44. The moving direction of the valve portion 43 (relief valve holder 42) is orthogonal to the direction in which the plunger 2 reciprocates. The center line of the relief valve mechanism 4 (the center line of the relief valve holder 42) is perpendicular to the center line of the plunger 2. Note that the moving direction of the valve portion 43 in the relief valve mechanism 4 corresponds to the second direction according to the present invention.

The seat member 44 has a fuel passage facing the valve portion 43. A side of the fuel passage in the seat member 44 opposite to the valve portion 43 communicates with the discharge passage 12a. The valve portion 43 closes the fuel passage by contacting (adhering to) the seat member 44 . This blocks the movement of fuel between the pressurizing chamber 11 (upstream side) and the sheet member 44 (downstream side).

When the pressure inside the common rail 106 and the members beyond it increases, the difference between the fuel pressure on the seat member 44 side (discharge chamber 87) and the fuel pressure in the pressurizing chamber 11 exceeds a set value. As a result, the fuel on the seat member 44 side presses the valve portion 43 and moves the valve portion 43 against the biasing force of the relief spring 41. As a result, the relief valve mechanism 4 opens, and the fuel in the discharge chamber 87 and the discharge passage 12a returns to the pressurizing chamber 11 through the fuel passage of the seat member 44. Therefore, the pressure that causes the valve portion 43 to open is determined by the biasing force of the relief spring 41.

[Positional relationship among the relief valve mechanism, discharge valve mechanism, and pressurizing chamber]
Next, the positional relationship among the relief valve mechanism 4, the discharge valve mechanism 8, and the pressurizing chamber 11 will be explained. As shown in FIGS. 4 and 5, when viewed from the direction in which the plunger 2 reciprocates, the movement direction of the valve part 43 (see FIG. 5) in the relief valve mechanism 4 is the same as the movement direction of the valve part 82 in the discharge valve mechanism 8. different from the direction. That is, when viewed from the direction in which the plunger 2 reciprocates, the moving direction of the valve portion 43 in the relief valve mechanism 4 intersects the moving direction of the valve portion 82 in the discharge valve mechanism 8. 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 direction in which the plunger 2 reciprocates, and the space inside the pump body 1 can be effectively utilized. Miniaturization can be achieved.

As shown in FIG. 4, the moving direction of the valve part 82 in the discharge valve mechanism 8 is the first radial direction of the pump body 1, and the moving direction of the valve part 43 in the relief valve mechanism 4 is the first radial direction of the pump body 1. This is a second radial direction different from the radial direction. Note that the angle at which the first radial direction and the second radial direction intersect shown in FIG. 4 is smaller than 90 degrees. However, the angle at which the first radial direction and the second radial direction intersect may be approximately 90 degrees. When viewed from the direction in which the plunger 2 reciprocates, the discharge valve mechanism 8 and the relief valve mechanism 4 may be arranged such that the moving directions of the valve parts 82 and 43 are substantially perpendicular to each other.

As shown in FIGS. 2 and 4, the relief valve mechanism 4 is arranged at a position overlapping the pressurizing chamber 11 in the direction in which the plunger 2 reciprocates and in the direction in which the valve portion 43 of the relief valve mechanism 4 moves. This eliminates the need to provide a passage for communicating the relief valve mechanism 4 and the pressurizing chamber 11. As a result, the dead volume of the pressurizing chamber 11 can be reduced compared to the case where a passage is provided for communicating the relief valve mechanism 4 and the pressurizing chamber 11, and the volumetric efficiency can be improved.

Volumetric efficiency refers to the movement distance from the discharge valve mechanism 8 to the top dead center of the plunger 2, where the volume of the pressurizing chamber 11 is the most reduced. This is the ratio of the amount of fuel that is discharged. Further, the bottom dead center of the plunger 2 is a position where the plunger 2 is at the lowest end (on the cam side of the engine). The top dead center of the plunger is the position where the plunger 2 is at its uppermost end.

As shown in FIG. 2, when viewed from a direction perpendicular to the direction in which the plunger 2 reciprocates and the direction in which the valve portion 43 of the relief valve mechanism 4 moves, the relief valve mechanism 4 has the following characteristics: It overlaps with the entire region parallel to the moving direction of the valve portion 43. Thereby, the fuel passing through the relief valve mechanism 4 can be efficiently returned to the pressurizing chamber 11.

As shown in FIGS. 3 and 5, the discharge valve mechanism 8 is arranged at a position overlapping the relief valve mechanism 4 when viewed from the moving direction of the valve portion 82 of the discharge valve mechanism 8. Thereby, the length of the pump body 1 in the direction in which the plunger 2 reciprocates (the length of the pump body 1 in the axial direction) can be shortened, and the pump body 1 can be made smaller.

Further, the lower end L1 of the second chamber 1b (relief chamber) in which the relief valve mechanism 4 is arranged is closer to the plunger 2 in the direction in which the plunger 2 reciprocates than the upper end L2 of the seat passage 8a in the discharge valve mechanism 8. placed in position. Further, the upper end of the seat passage 8a in the discharge valve mechanism 8 is higher than the upper surface of the plunger 2 (see FIG. 6) located at the top dead center.

As shown in FIG. 5, the upper end of the relief valve mechanism 4 is located farther from the plunger 2 than the upper end of the discharge valve mechanism 8 in the direction in which the plunger 2 reciprocates. Further, as shown in FIG. 3, the relief valve mechanism 4 is arranged at a position overlapping the discharge valve mechanism 8 when viewed from a horizontal direction perpendicular to the direction in which the plunger 2 reciprocates. Thereby, the length of the pump body 1 in the direction in which the plunger 2 reciprocates (the length of the pump body 1 in the axial direction) can be shortened, and the pump body 1 can be made smaller.

Furthermore, in this embodiment, the first chamber 1a and the second chamber 1b provided in the pump body 1 partially overlap with each other. The discharge valve inlet passage 8a directly communicates with the first chamber 1a and the second chamber 1b. Thereby, the dead volume of the pressurizing chamber 11 can be reduced, and the size of the pump body 1 can be reduced.

Conventionally, the discharge valve inlet passage communicated only with the first chamber. In this case, if the plunger located at the top dead center blocks the discharge valve inlet passage, a sufficient amount of fuel will not flow to the discharge valve mechanism. Therefore, conventionally, it was necessary to secure a space in the pump body in the direction in which the plunger reciprocates, and to arrange the discharge valve inlet passage at a position where it would not be blocked by the plunger located at the top dead center.

However, in the high-pressure fuel supply pump 100 according to the present embodiment, the discharge valve inlet passage 8a communicates not only with the first chamber 1a but also with the second chamber 1b. Therefore, a sufficient amount of fuel can flow to the discharge valve mechanism without securing a space in the pump body 1 in the direction in which the plunger 2 reciprocates. Moreover, the structure of the passage communicating with the first chamber 1a can be simplified, and processing costs can be reduced. Furthermore, since the diameter of the discharge valve inlet passage 8a can be made large, pressure loss can be reduced, contributing to improved performance.

When holes such as the first chamber 1a, the second chamber 1b, and the communication hole 1e are formed in the pump body 1, unnecessary protrusions (burrs) are generated on the processed surface. If the protrusions (burrs) are left in place, errors may occur in the hole dimensions, making it impossible to install parts or causing injury if touched, so remove the protrusions (burrs). There is a need to. In the embodiment described above, the diameter of the communication hole 1e is the same as the diameter of the first chamber 1a. Therefore, processing of the communicating hole 1e becomes easy, and protrusions (burrs) can be easily removed. Moreover, the shape of the pump body 1 can be prevented from becoming complicated. Therefore, productivity of the pump body 1 and the high-pressure fuel supply pump 100 can be improved, and costs can be reduced. Incidentally, if the diameter of the discharge valve inlet passage 8a is increased, the hole (passage) can be easily machined and burrs can be easily removed. As a result, quality can be improved.

Further, since the diameter of the communication hole 1e is the same as the diameter of the first chamber 1a, fuel easily flows from the relief valve 4 to the pressurizing chamber 11, and the relief performance can be improved. Furthermore, since the relief valve is directly integrated into the second chamber 1b provided in the pump body 1, the housing (seat member) that houses the parts that make up the relief valve can be omitted, reducing the number of parts and reducing costs. can be achieved.

[High pressure fuel pump operation]
Next, the operation of the high-pressure fuel pump according to this embodiment will be explained using FIGS. 2 and 4.

In FIG. 2, when the plunger 2 is lowered and the electromagnetic suction valve mechanism 3 is open, fuel flows into the pressurizing chamber 11 from the suction passage 1d. Hereinafter, the stroke in which the plunger 2 descends will be referred to as a suction stroke. On the other hand, when the plunger 2 rises and the electromagnetic suction valve mechanism 3 is closed, the fuel in the pressurizing chamber 11 is pressurized and passes through the discharge valve mechanism 8 to the common rail 106 (see FIG. 1). be pumped. Hereinafter, the process in which the plunger 2 rises will be referred to as an upward stroke.

As described above, if the electromagnetic suction valve mechanism 3 is closed during the ascending stroke, the fuel sucked into the pressurizing chamber 11 during the suction stroke is pressurized. As a result, the discharge valve mechanism 8 opens, and the fuel in the pressurizing chamber 11 is discharged to the common rail 106 side. On the other hand, if the electromagnetic suction valve mechanism 3 is open during the ascending process, the fuel in the pressurizing chamber 11 is pushed back toward the suction passage 1d. Therefore, the fuel in the pressurizing chamber 11 is not discharged to the common rail 106 side. In this way, the discharge of fuel by the high-pressure fuel supply pump 100 is controlled by opening and closing the electromagnetic intake valve mechanism 3. Opening and closing of the electromagnetic intake 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 within the pressurizing chamber 11 decreases. This reduces the fluid pressure difference between the suction port 31b and the pressurizing chamber 11 (hereinafter referred to as "the fluid pressure difference before and after the valve portion 32"). When the biasing force of the rod biasing spring 34 becomes greater than the fluid pressure difference across the valve portion 32, the rod 33 moves in the valve opening direction. As a result, the valve portion 32 separates from the seating portion 31a of the suction valve seat 31, and the electromagnetic suction valve mechanism 3 becomes open.

When the electromagnetic suction valve mechanism 3 is in the open state, 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) in the stopper 37, and enters the pressurizing chamber. 11. When the electromagnetic suction valve mechanism 3 is in the open state, 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 regulated. The gap existing between the valve portion 32 and the seating portion 31a in the 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 suction stroke, the engine moves to the ascending stroke. At this time, the electromagnetic coil 35 remains in a non-energized state, and no magnetic attraction force is acting between the anchor 36 and the magnetic core 39. The valve portion 32 has a biasing force in the valve opening direction corresponding to the difference between the biasing forces between the rod biasing spring 34 and the valve biasing spring 38, and a backflow of fuel from the pressurizing chamber 11 to the low pressure fuel flow path 10a. The force that presses the valve in the closing direction is exerted by the fluid force generated when the valve is closed.

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

In the return process, when a control signal from the ECU 101 (see FIG. 1) is applied to the electromagnetic intake valve mechanism 3, a current flows through the electromagnetic coil 35 via the terminal member 40. When 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 (away from the valve portion 32) against the biasing force of the rod biasing spring 34.

When the anchor 36 (rod 33) moves in the valve closing direction, the valve portion 32 is released from the biasing force in the valve opening direction. As a result, the valve portion 32 moves in the valve closing direction due to the biasing force of the valve biasing spring 38 and the fluid force caused by the fuel flowing into the suction passage 10b. When the valve portion 32 contacts 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 enters the closed state.

After the electromagnetic intake valve mechanism 3 enters the closed state, the pressure of the fuel in the pressurizing chamber 11 is increased as the plunger 2 rises. When the pressure in the pressurizing chamber 11 exceeds a predetermined pressure, the fuel passes through the discharge valve mechanism 8 and is discharged to the common rail 106 (see FIG. 1). This stroke is called a discharge stroke. That is, the upward stroke of the plunger 2 from the bottom dead center to the top dead center consists of a return stroke and a discharge stroke. By controlling the timing at which the electromagnetic coil 35 of the electromagnetic intake valve mechanism 3 is energized, the amount of high-pressure fuel discharged can be controlled.

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

2. Second Embodiment Next, a high-pressure fuel supply pump according to a second embodiment of the present invention will be described. The high-pressure fuel supply pump according to the second embodiment differs from the high-pressure fuel supply pump 100 according to the first embodiment in the position of the discharge valve mechanism 8. Therefore, here, the position of the discharge valve mechanism 8 will be explained, and the explanation of the configuration and operation common to the high-pressure fuel supply pump 100 according to the first embodiment will be omitted.

[Positional relationship among the relief valve mechanism, discharge valve mechanism, and pressurizing chamber]
The positional relationship among the relief valve mechanism 4, the discharge valve mechanism 8, and the pressurizing chamber 11 will be explained with reference to FIGS. 6 and 7. FIG. 6 is a longitudinal cross-sectional view of the high-pressure fuel supply pump according to the second embodiment, taken in a cross section perpendicular to the horizontal direction. FIG. 7 is a partially cutaway perspective sectional view of the high-pressure fuel supply pump according to the second embodiment.

The high-pressure fuel supply pump 200 according to the second embodiment has the same configuration as the high-pressure fuel supply pump 100 according to the first embodiment. As shown in FIG. 7, when viewed from the direction in which the plunger 2 reciprocates, the moving direction of the valve portion 43 in the relief valve mechanism 4 is different from the moving direction of the valve portion 82 in the discharge valve mechanism 8. That is, when viewed from the direction in which the plunger 2 reciprocates, the moving direction of the valve portion 43 in the relief valve mechanism 4 intersects the moving direction of the valve portion 82 in the discharge valve mechanism 8.

As shown in FIG. 7, the relief valve mechanism 4 is arranged at a position overlapping the pressurizing chamber 11 in the direction in which the plunger 2 reciprocates and in the direction in which the valve portion 43 of the relief valve mechanism 4 moves. As shown in FIGS. 6 and 7, the discharge valve mechanism 8 is arranged at a position overlapping the relief valve mechanism 4 when viewed from the moving direction of the valve portion 82 of the discharge valve mechanism 8.

Further, the lower end L1 of the second chamber 1b (relief chamber) in which the relief valve mechanism 4 is arranged is closer to the plunger 2 in the direction in which the plunger 2 reciprocates than the upper end L2 of the seat passage 8a in the discharge valve mechanism 8. placed in position. Further, the upper end of the seat passage 8a in the discharge valve mechanism 8 is higher than the upper surface of the plunger 2 (see FIG. 6) located at the top dead center.

As shown in FIG. 7, the upper end of the relief valve mechanism 4 and the upper end of the discharge valve mechanism 8 are set at substantially the same height in the direction in which the plunger 2 reciprocates. Further, as shown in FIG. 6, the relief valve mechanism 4 is arranged at a position overlapping the discharge valve mechanism 8 when viewed from a horizontal direction perpendicular to the direction in which the plunger 2 reciprocates.

Furthermore, when viewed from the moving direction of the valve portion 43 of the relief valve mechanism 4, the discharge valve mechanism 8 overlaps the entire region of the relief valve mechanism 4 in the direction in which the plunger 2 reciprocates. As a result, the length of the pump body 1 in the direction in which the plunger 2 reciprocates (the length of the pump body 1 in the axial direction) can be made shorter than in the first embodiment, and the pump body 1 can be made smaller. be able to.

3. Summary As explained above, the high-pressure fuel supply pump (fuel pump) according to the embodiment described above has the pump body 1 (in which the pressurizing chamber 11 (pressurizing chamber) and the discharge chamber 87 (discharge chamber) are provided). A plunger 2 (plunger) that reciprocates in the pressurizing chamber 11, and a discharge valve mechanism 8 (discharge valve mechanism) that discharges fuel from the pressurizing chamber 11 into a discharge chamber 87. Further, the high-pressure fuel supply pump opens when the difference between the fuel pressure in the discharge chamber 87 and the fuel pressure in the pressurizing chamber 11 exceeds a set value, and supplies the fuel in the discharge chamber 87 to the pressurizing chamber 11. A relief valve mechanism 4 (relief valve mechanism) for returning is provided. When viewed from the first direction, which is the direction in which the plunger 2 reciprocates, the discharge valve mechanism 8 and the relief valve mechanism 4 are arranged such that the moving directions of the valve parts 82 and 43 (valves) intersect with each other. The relief valve mechanism 4 is arranged at a position overlapping the pressurizing chamber 11 in the first direction and in the second direction, which is the moving direction of the valve part 43 in the relief valve mechanism 4.

Thereby, the discharge valve mechanism 8 and the relief valve mechanism 4 can be arranged at positions that do not overlap with each other in the first direction. As a result, the space inside the pump body 1 can be effectively utilized and the size of the pump body 1 can be reduced. Further, there is no need to provide a passage for communicating the relief valve mechanism 4 and the pressurizing chamber 11. Therefore, the dead volume of the pressurizing chamber 11 can be reduced more than in the case where a passage is provided for communicating the relief valve mechanism 4 and the pressurizing chamber 11, and the volumetric efficiency can be improved.

Further, in the high-pressure fuel supply pump (fuel pump) according to the embodiment described above, the discharge valve mechanism 8 (discharge valve mechanism) 8 is is arranged at a position overlapping with the relief valve mechanism 4 (relief valve mechanism). Thereby, the length of the pump body 1 (pump body) in the first direction (the length of the pump body 1 in the axial direction) can be shortened, and the pump body 1 can be made smaller.

Further, in the high-pressure fuel supply pump (fuel pump) according to the embodiment described above, the lower end L1 of the second chamber 1b (relief chamber) in which the relief valve mechanism 4 (relief valve mechanism) is arranged is connected to the discharge valve mechanism 8 (discharge valve mechanism). It is arranged at a position closer to the plunger 2 (plunger) in the first direction than the upper end L2 of the seat passage 8a (passage on the pressure chamber side) in the valve mechanism (valve mechanism). Thereby, the length of the pump body 1 (pump body) in the first direction (the length of the pump body 1 in the axial direction) can be shortened, and the pump body 1 can be made smaller.

Furthermore, in the high-pressure fuel supply pump (fuel pump) according to the embodiment described above, when viewed from the first direction, the discharge valve mechanism 8 (discharge valve mechanism) and the relief valve mechanism 4 (relief valve mechanism) have mutual valve sections. The moving directions of the valves 82 and 43 (valve) may be substantially perpendicular to each other. Thereby, it is possible to open a space between the discharge valve mechanism 8 and the relief valve mechanism 4 and prevent them from interfering with each other. Further, the space inside the pump body 1 can be effectively utilized, and the pump body 1 can be made smaller.

Furthermore, in the high-pressure fuel supply pump (fuel pump) according to the embodiment described above, when viewed from the horizontal direction orthogonal to the first direction, the relief valve mechanism 4 (relief valve mechanism) is the discharge valve mechanism 8 (discharge valve mechanism). It is placed in a position that overlaps with Thereby, the length of the pump body 1 (pump body) in the first direction (the length of the pump body 1 in the axial direction) can be shortened, and the pump body 1 can be made smaller.

Further, in the high-pressure fuel supply pump (fuel pump) according to the second embodiment described above, when viewed from the second direction, the discharge valve mechanism 8 (discharge valve mechanism) is the first in the relief valve mechanism 4 (relief valve mechanism). Overlaps the entire area in one direction. Thereby, the length of the pump body 1 in the first direction (the length of the pump body 1 in the axial direction) can be made shorter than in the first embodiment, and the size of the pump body 1 can be reduced.

Further, in the high-pressure fuel supply pump (fuel pump) according to the first embodiment described above, the upper end of the relief valve mechanism 4 (relief valve mechanism) is higher than the upper end of the discharge valve mechanism 8 (discharge valve mechanism). It is arranged at a position far from the plunger 2 (plunger) in the direction. Thereby, the discharge valve mechanism 8 is arranged closer to the plunger 2 in the first direction than the relief valve mechanism 4 is. The relief valve mechanism 4 needs to be set at a position higher than the top dead center of the plunger 2 in order to avoid interference with the plunger 2. Therefore, by disposing the discharge valve mechanism 8 closer to the plunger 2 in the first direction than the relief valve mechanism 4, it is possible to suppress the pump body 1 from becoming longer in the first direction.

Moreover, in the high-pressure fuel supply pump (fuel pump) according to the embodiment described above, the relief valve mechanism 4 (relief valve mechanism) is overlaps with the entire area parallel to the second direction of the pressure chamber). Thereby, the fuel passing through the relief valve mechanism 4 can be efficiently returned to the pressurizing chamber 11.

In the high-pressure fuel supply pump (fuel pump) according to the embodiment described above, the upper end of the seat passage 8a (passage on the pressure chamber side) in the discharge valve mechanism 8 (discharge valve mechanism) is connected to the plunger located at the top dead center. Higher than the top of 2. Thereby, the plunger 2 located at the top dead center can be prevented from blocking the seat passage 8a. As a result, the discharge of fuel by the discharge valve mechanism 8 can be prevented from being obstructed.

The embodiments of the fuel pump of the present invention have been described above, including their effects. However, the fuel pump of the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the gist of the invention as set forth in the claims. Further, the embodiments described above have been described in detail to explain the present invention in an easy-to-understand manner, and are not necessarily limited to those having all the configurations described.

For example, in the embodiment described above, the moving direction of the valve part 32 in the electromagnetic suction valve mechanism 3 is the same second radial direction as the moving direction of the valve part 43 in the relief valve mechanism 4 (see FIG. 2). However, the moving direction of the valve part in the relief valve according to the present invention may be different from the moving direction of the valve part in the electromagnetic suction valve. For example, in the fuel pump according to the present invention, the direction of movement of the valve part of the relief valve, the direction of movement of the valve part of the electromagnetic intake valve, and the direction of movement of the valve part of the discharge valve may all be different.

Further, in the embodiment described above, the discharge valve mechanism 8 and the valve parts 82 and 43 of the relief valve mechanism 4 move in a direction perpendicular to the direction in which the plunger 2 reciprocates (the first direction). However, the direction in which the valves of the discharge valve mechanism and the relief valve mechanism according to the present invention move may be inclined with respect to the direction perpendicular to the direction (first direction) in which the plunger 2 reciprocates. That is, the discharge valve mechanism and the relief valve mechanism may be connected obliquely to the pressurizing chamber.

1...Pump body, 1a...First chamber, 1b...Second chamber (relief chamber), 1c...Third chamber, 1d...Suction passage, 1e...Communication hole, 1f...Discharge valve inlet passage, 2...Plunger, 3... Electromagnetic suction valve mechanism, 4...Relief valve mechanism, 5...Suction joint, 6...Cylinder,
8...Discharge valve mechanism, 8a...Seat passage, 9...Pressure pulsation reduction mechanism, 10...Low pressure fuel chamber, 11...Pressure chamber, 12...Discharge joint, 41...Relief spring, 42...Relief valve holder, 43...Valve part , 44... Seat member, 81... Discharge valve seat, 82... Valve section,
83...Discharge valve spring, 84...Discharge valve stopper, 85...Plug, 87...Discharge chamber, 100,200...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 (9)

a pump body provided with a pressurization chamber and a discharge chamber;
a plunger that reciprocates in the pressurized chamber;
a discharge valve mechanism that discharges fuel in the pressurized chamber to the discharge chamber;
a relief valve mechanism that opens when the difference between the fuel pressure in the discharge chamber and the fuel pressure in the pressurization chamber exceeds a set value and returns the fuel in the discharge chamber to the pressurization chamber. In the fuel pump,
When viewed from a first direction, which is the direction in which the plunger reciprocates, the discharge valve mechanism and the relief valve mechanism are arranged in a direction in which the moving directions of the respective valves intersect,
The relief valve mechanism is arranged at a position overlapping the pressurizing chamber in the first direction and a second direction that is a movement direction of the valve in the relief valve mechanism ,
The discharge valve inlet passage of the discharge valve mechanism is in direct communication with the relief chamber in which the relief valve mechanism is arranged and the pressurization chamber.
Fuel pump. The fuel pump according to claim 1, wherein the discharge valve mechanism is arranged at a position overlapping the relief valve mechanism when viewed from a third direction that is a moving direction of the valve in the discharge valve mechanism. The lower end of the relief chamber in which the relief valve mechanism is arranged is located closer to the plunger in the first direction than the upper end of the passage on the pressure chamber side in the discharge valve mechanism. Fuel pump as described. The fuel pump according to claim 1, wherein the discharge valve mechanism and the relief valve mechanism are arranged such that moving directions of the respective valves are substantially perpendicular to each other when viewed from the first direction. The fuel pump according to claim 1, wherein the relief valve mechanism is arranged at a position overlapping the discharge valve mechanism when viewed from a horizontal direction perpendicular to the first direction. The fuel pump according to claim 5, wherein the discharge valve mechanism overlaps the entire area of the relief valve mechanism in the first direction when viewed from the second direction. The fuel pump according to claim 1, wherein an upper end of the relief valve mechanism is located farther from the plunger in the first direction than an upper end of the discharge valve mechanism. The fuel pump according to claim 1, wherein the relief valve mechanism overlaps the entire area of the pressurizing chamber parallel to the second direction when viewed from a direction perpendicular to the first direction and the second direction. The fuel pump according to claim 1, wherein the upper end of the passage on the pressure chamber side in the discharge valve mechanism is higher than the upper surface of the plunger located at top dead center.