JP3877863B2 - Pressure control mechanism of fuel injection pump - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a pressure adjusting mechanism that adjusts a pressure in a barrel port or a gallery chamber in a fuel injection pump.
[0002]
[Prior art]
FIG. 11 shows a typical fuel injection pump used in a diesel engine. In this fuel injection pump, a pump chamber (3) is formed in a plunger barrel (2) fitted in the pump body (1), and in a delivery holder (4) attached to the upper part of the plunger barrel (2). The delivery oil passage (5) communicating with the pump chamber (3) is formed in the pump chamber (3), and the plunger (6) slides back and forth in the pump chamber (3), thereby allowing the delivery oil passage (5) to pass through. The fuel is pumped to the fuel injection valve.
[0003]
The plunger barrel (2) is formed with a barrel port (7) (7) in a direction perpendicular to the sliding direction of the plunger (6), and this barrel port (7) (7) is formed in the pump body (1). Communicated with the annular gallery room (8). The opening on the gallery chamber (8) side of the barrel ports (7) and (7) has deflectors (9) and (9) for suppressing spills at the end of injection from the pump chamber (3) to the gallery chamber (8). ) Is attached.
[0004]
Further, the pump body (1) is provided with a fuel suction passage (10) and a fuel discharge passage (11) for communicating the gallery chamber (8) with the outside, and fuel is sent from the fuel suction passage (10) to the gallery. It is supplied into the pump chamber (3) through the chamber (8) and the barrel port (7), and the escape oil is discharged from the fuel discharge passage (11) through the barrel port (7) and the gallery chamber (8). It is like that.
[0005]
In such a fuel injection pump, recently, it has been required to increase fuel injection pressure and improve fuel efficiency as a countermeasure against exhaust gas, and accordingly, delivery oil from the pump chamber (3) to the fuel injection valve is required. Road (5) tends to increase internal pressure. For this reason, the reverse flow (back flow) of the fuel from the delivery oil passage (5) during the fuel pumping process becomes strong, and particularly the back flow immediately before injection becomes very high, and the internal pressure of the barrel ports (7) (7) The gallery room (8) internal pressure has become negative and the tendency to generate bubbles is increasing. If these bubbles remain even during the fuel injection period, the bubbles are crushed due to a sudden pressure rise at the time of fuel inflow (spill) at the end of injection, and the barrel ports (7) (7) wall surface and plunger (6 ) There was a harmful effect that cavitation erosion occurred on the surface and gallery room (8) wall surface.
[0006]
Therefore, a pressure regulating mechanism is arranged to increase the internal pressure of the barrel port (7) (7) and the internal pressure of the gallery chamber (8) during fuel injection from the start of fuel supply before the spill, and to suppress the pressure drop due to backflow. Various measures are taken such as setting up. The applicant of the present invention provides a fuel injection pump pressure regulating mechanism (see Japanese Patent Laid-Open No. 8-296528) in which a check valve is provided at the fuel inlet of the pump body and a two-stage pressure regulating valve is provided at the fuel outlet of the pump body. is suggesting. In this fuel injection pump, the check valve on the fuel inlet side is closed during the fuel pumping process, and the valve with the smaller outflow area is opened in the two-stage pressure regulating valve on the fuel outlet side. The internal pressure from the pump room to the gallery room is increased to reduce the pressure drop due to backflow. Accordingly, since no bubbles are generated in the barrel port or the gallery chamber, cavitation erosion does not occur at the end of injection.
[0007]
In addition, when spilling at the end of injection, the valve with the larger outflow area is also opened in the two-stage pressure regulating valve, and the internal pressures of the gallery chamber, barrel port, and pump chamber are rapidly lowered, thereby The pressure is also quickly reduced, and the needle valve in the fuel injection valve is also quickly closed once at the end of injection, so that deterioration in combustion performance due to an increase in the injection amount during the valve closing operation can be avoided. Further, the durability of the O-ring can be ensured.
[0008]
[Problems to be solved by the invention]
However, in the conventional pressure regulating mechanism including the pressure regulating mechanism of the fuel injection pump described in the above publication, the check valve or the pressure regulating valve is provided separately in the pump body, or in a valve chamber formed in the pump body. Although it is mounted, it has a structure in which a part thereof protrudes outward from the pump body.
[0009]
In such a case, the valve case or the like that houses the check valve or the pressure regulating valve protrudes greatly from the pump body, leading to an increase in size, and when assembling the fuel injection pump into the engine, consider the space that protrudes. There was a need to change the engine structure. In addition, there is a problem that the number of parts increases and the manufacturing cost increases.
[0010]
In view of the above, an object of the present invention is to provide a pressure regulating mechanism for a fuel injection pump that can reduce the number of parts and reduce the cost without causing an increase in size of the pump.
[0011]
[Means for Solving the Problems]
In order to solve the above problems, the present invention provides a plunger that reciprocally slides in a pump body while supplying fuel from a fuel inlet formed in the pump body into a gallery chamber that communicates with a barrel port via a check valve. In the pressure adjustment mechanism of the fuel injection pump, the fuel is pumped to the fuel injection valve and the fuel in the gallery chamber is discharged from the fuel outlet formed in the pump main body via the pressure control valve. The check valve is slidably accommodated in the first valve chamber formed in the first valve chamber, and the pressure regulating valve is slidably accommodated in the second valve chamber formed on the fuel outlet side of the pump body. A pressure regulating mechanism of a fuel injection pump in which a pressure valve is incorporated in the pump main body, and further accommodated in a sliding direction of a check valve accommodated in the first valve chamber and in a second valve chamber. Key It is characterized in that arranged along the sliding direction of the valve in the sliding direction of the plunger.
[0012]
Specifically, attach the lid for closing the respective valve chamber to fit the valve chamber.
[0013]
The lid body includes a valve seat on which each valve is seated, and a pressing member that is screwed into each valve chamber so as to press the valve seat against a step formed in each valve chamber. A seal member is attached to the pressing member. The pressure regulating valve includes an outer valve in which the valve opening pressure and the outflow area are set large, and an inner valve fitted in the outer valve and in which the valve opening pressure and the outflow area are set small. It is a two-stage type.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 shows a configuration of a pressure regulating mechanism of a fuel injection pump according to the first embodiment of the present invention. The other basic configuration other than the pressure adjusting mechanism is substantially the same as the conventional one, and the members having the same functions as the conventional ones are denoted by the same reference numerals in the drawing.
[0015]
This pressure regulating mechanism is incorporated in the check valve (21) incorporated in the fuel inlet (20) side of the pump body (1) and in the fuel outlet (22) side of the pump body (1). A pressure regulating valve (23) and supplying fuel such as A heavy oil from the fuel inlet (20) into the gallery chamber (8) communicating with the barrel port (7) via the check valve (21); The fuel in the gallery chamber (8) is discharged from the fuel outlet (22) through the pressure regulating valve (23).
[0016]
On the fuel inlet (20) side of the pump body (1), as shown in FIG. 2, a bottomed first valve chamber (24) is formed from the upper surface toward the sliding direction of the plunger (6), that is, in the vertical direction. Is formed. The first valve chamber (24) has steps (25) and (26) at the center and lower end thereof, thereby forming three storage portions (27), (28) and (29) having different diameters. Yes. Of these, the upper large-diameter storage part (27) communicates with the fuel inlet (20) via the horizontal fuel intake passage (30), and the central-side intermediate-diameter storage part (28) It communicates with the gallery room (8) through the passage (31). A check valve (21) is slidably accommodated from the medium diameter accommodating part (28) to the small diameter accommodating part (29). The check valve (21) includes a valve body (37) and a check valve spring (32) fitted from the inner central hole to the lower small-diameter storage portion (29).
[0017]
The limit lift of the check valve (21) is the distance between the lower end of the valve body (37) and the lower step (25) of the pump body (1), and the valve body (37 ) Is slidable. The valve opening set pressure of the check valve (21) is set to be equal to or lower than the discharge pressure of the fuel feed pump that supplies fuel to the fuel inlet (20).
[0018]
In addition, a lid (34) with an O-ring (33) as a sealing member is attached to the large-diameter storage part (27) so as to be accommodated in the large-diameter storage part (27). The valve chamber (24) is hermetically sealed so that fuel in the first valve chamber (24) does not leak. The lid (34) has a valve seat (35) on which the check valve (21) is seated, and an opening in the first valve chamber (24) so as to press the valve seat (35) against the upper step (26). A pressing member (36) that is screwed into the part is integrated. The valve seat (35) is formed with a passage for guiding fuel from the fuel inlet (20) to the upper end of the check valve (21).
[0019]
On the other hand, a bottomed second valve chamber (40) is formed on the fuel outlet (22) side of the pump body (1) as shown in FIG. The second valve chamber (40) has two steps (41) and (42) at its center, slightly closer to the lower end and closer to the upper end, whereby three storage portions (43), (44) ( 45) is formed. Of these, the upper large-diameter storage portion (43) communicates with the gallery chamber (8) through the horizontal fuel passage (46), and the middle-side storage portion (44) in the central side communicates with the horizontal fuel discharge passage. It communicates with the fuel outlet (22) via (47).
[0020]
A pressure regulating valve (23) is slidably accommodated from the medium diameter accommodating part (44) to the small diameter accommodating part (45). The pressure regulating valve (23) includes an outer valve (48) in which the valve opening pressure and the fuel flow passage area are set large, and the valve opening pressure and the fuel flow passage area that are fitted in the outer valve (48) to reduce the valve opening pressure and the fuel flow passage area. The inner valve (49) is set.
[0021]
The inner valve (49) has three small holes (50), (50) and (50) formed at the upper end thereof, and the small hole (50) in the center is formed by a fuel passage (46) and a fuel discharge passage (47). And an air vent hole for always communicating with each other. A central fuel passage (51) communicating with the small holes (50) (50) (50) is formed inside the inner valve (49). An inner valve stopper (52) fitted inside the outer valve (48) is arranged below the inner valve (49), and the inner valve stopper is inserted from the central fuel passage (51) of the inner valve (49). An inner valve spring (53) is fitted into the upper end of the through hole of (52).
[0022]
On the other hand, the outer valve (48) functions as a valve seat for the inner valve (49), and a fuel passage hole (54) into which the upper end of the inner valve (49) is fitted is formed at the center of the upper end. Yes. Further, an outer fuel passage (55) communicating with the fuel discharge passage (47) is formed in the vertical direction on the outer peripheral portion of the outer valve (48), and the outer fuel passage (55) is a side surface of the outer valve (48). The central fuel passage (51) of the inner valve (49) communicates with the fuel passage hole (56) formed in the inner valve (49). As a result, when the inner valve (49) and the outer valve (48) are opened, the fuel in the medium diameter storage part (44) and the small diameter storage part (45) is allowed to escape to the fuel discharge passage (47). Yes.
[0023]
The lower end of the outer valve (48) is in contact with the spring receiving member (57). A through hole communicating with the central fuel passage (51) of the inner valve (49) is formed in the center of the spring receiving member (57), and the outer valve spring (58) extends from the through hole to the small diameter storage portion (45). Is fitted.
[0024]
The limit lift of the pressure regulating valve (23) is the distance between the lower end of the inner valve (49) and the upper end of the inner valve stopper (52), and the spring receiving member (57) in the outer valve (48). The distance between the lower end of the second valve chamber and the lower step (41) in the second valve chamber (40), and the inner valve (49) and the outer valve (48) can be slid within the limit lift range. ing.
[0025]
Further, the valve opening pressure of the pressure regulating valve (23) is set to be lower than the internal pressure of the gallery chamber (8) during backflow in the inner valve (49), and the gallery chamber (8) during backflow in the outer valve (48). The internal pressure is set to be less than the internal pressure of the gallery room (8) during spilling. Moreover, the fuel outflow area when the inner valve (49) is opened is set to be small so that the pressure in the gallery chamber (8) can be maintained at a high pressure, and the fuel when the outer valve (48) is opened. The channel area is set large so that the pressure in the gallery room (8) during spilling can be rapidly reduced.
[0026]
A lid (60) with an O-ring (59) is attached to the large-diameter storage part (43) so as to fit within the large-diameter storage part (43), thereby the second valve chamber (40) It is sealed so that fuel in the second valve chamber (40) does not leak. The lid (60) includes a valve seat (61) on which the outer valve (48) is seated, and an opening of the second valve chamber (40) so as to press the valve seat (61) against the upper step (42). And a pressing member (62) that is screwed into the unitary structure. The valve seat (61) is formed with a passage for guiding fuel from the gallery chamber (8) to the upper end of the outer valve (48).
[0027]
In order to prevent fuel from leaking from the gallery chamber (8), the gallery chamber (8) is interposed between the pump body (1) and the plunger barrel (2) as shown in FIG. An O-ring (63) is attached in the vicinity of.
[0028]
In addition, the fuel leaking from between the plunger barrel (2) and the plunger (6) is returned to the upstream side of the check valve (21) through the leak return hole (64) to the plunger barrel (2). The pressure applied to the formed leak groove (65) is kept constant (feed pressure). The leak return hole (64) is formed from the leak groove (65) to the fuel inlet (20) in an oblique direction from the plunger barrel (2) to the pump body (1). The same effect can be obtained by forming the leak return hole (64) from the leak groove (65) toward the fuel outlet (22) and letting it escape to the downstream side of the pressure regulating valve (23).
[0029]
FIG. 5 shows the configuration of the pressure regulating valve side of the pressure regulating mechanism according to the second embodiment. In this embodiment, the valve seat (61) and the pressing member (62) in the lid (60) are separated and the O-ring (59) is attached to the valve seat (61) side. Thus, the valve seat (61) is housed in the valve chamber (40), and the valve seat (61) is pressed against the upper step (42) in the valve chamber (40). By screwing the pressing member (61) into the O-ring (59), the O-ring (59) does not rotate and is not deformed or cut off, and fuel leakage from the valve chamber (40) can be reliably prevented. it can. This structure is the same on the check valve (21) side. Other configurations are the same as those of the first embodiment, and members having the same functions as those of the first embodiment are denoted by the same reference numerals in the drawing.
[0030]
FIG. 6 shows the configuration of the pressure regulating valve side of the pressure regulating mechanism according to the third embodiment. In the present embodiment, on the pressure regulating valve side, the inner valve stopper (52) and the spring receiving member (57) that receives the outer valve spring (58) are integrated, and the dual-purpose member (66) has a large spring constant. The outer valve spring (58) is always pressed against the lower end of the outer valve (48). As a result, the risk of the inner valve stopper (52) rattling due to long-term use or dropping off when it is severe can be eliminated, and durability can be improved. In addition, the number of parts can be reduced to simplify the assembly process and reduce the cost.
[0031]
Further, in the structure of the lid (60), the valve seat (61) and the pressing member (62) are separated from each other, and the O-ring (59 on the outer side, that is, above the screw portion (67) of the pressing member (62). ) Is attached. As a result, the pulsating pressure from the gallery chamber (8) acts on the O-ring (59) not directly but via the screw portion (67), and wear of the O-ring (59) can be reduced. Other configurations are the same as those of the second embodiment, and members having the same functions as those of the second embodiment are denoted by the same reference numerals in the drawing.
[0032]
FIG. 7 shows a configuration of a pressure regulating mechanism according to the fourth embodiment. In the present embodiment, the first valve chamber (24) has a step (26) only at the center thereof, thereby eliminating the lower small-diameter storage portion (29) and the large-diameter storage portion (27). Two storage portions of the diameter storage portion (28) are formed. Then, a spring receiving member (70) that receives the check valve spring (32) is fitted into the bottom of the medium diameter storage portion (28), and the spring receiving member (70) is lifted by the check valve (21). It also functions as a stopper to limit the amount.
[0033]
As shown in FIG. 8, the second valve chamber (40) also has a step (42) only near the center and slightly to the upper end, thereby eliminating the lower small diameter storage portion (45) and storing the large diameter. Two storage parts are formed, a part (43) and a medium diameter storage part (44). Then, a spring receiving member (71) for receiving the outer valve spring (58) is fitted into the bottom of the medium diameter storage portion (44), and the lift amount of the outer valve (48) is set to the spring receiving member (71). It also functions as a limiting stopper. As a result, the pump body (1) and the springs (32) and (58) directly rub against each other, or the valves (21) and (23) may directly collide with the steps of the valve chambers (24) and (40). In addition, it is possible to reduce wear of the pump body (1), its stepped portions, and the springs (32) and (58).
[0034]
Furthermore, the fuel passage (31) on the fuel inlet (20) side is positioned below the fuel passage (46) on the fuel outlet (22) side, and these are formed on the same axis in the oblique direction. Thereby, the fuel passage (31) on the fuel inlet (20) side and the fuel passage (46) on the fuel outlet (22) side are formed by one hole drilling from the side surface on the fuel inlet (20) side of the pump body (1). ) Can be formed at the same time, and the manufacturing process can be simplified and the cost can be reduced.
[0035]
In this case, a communication hole (72) communicating with the first valve chamber (24) is formed by drilling on the side surface of the pump body (1) on the fuel inlet (20) side. The communication hole (72) is closed using a plug (73) that fits in the space.
[0036]
If a cylindrical sleeve for blocking communication with the communication hole (72) is inserted into the first valve chamber (24), screwing of the plug portion in the communication hole (72) is eliminated, and further cost reduction is achieved. Moreover, since it is not necessary to consider the wall thickness for mounting the plug (73) in the pump body (1), the wall thickness of the pump body (1) can be reduced, and the pump can be made compact. You can also. Other configurations are the same as those of the third embodiment, and members having the same functions as those of the third embodiment are denoted by the same reference numerals in the drawing.
[0037]
Next, the operation of the pressure adjusting mechanism of the fuel injection pump described above will be described. Since the operation of the pressure regulating mechanism of each embodiment is basically the same, description will be made based on the pressure regulating mechanism of the fourth embodiment. The fuel discharged from the fuel feed pump is filled into the gallery chamber (8) from the fuel suction passage (30) through the check valve (21), and is further passed through the barrel port (7) through the gap of the deflector (9). It is fed into the pump chamber (3). When the plunger (6) slides upward and the volume of the pump chamber (3) decreases, the fuel in the pump chamber (3) passes through the valve port (7) to the gallery chamber (8). Backflow.
[0038]
As a result, when the internal pressure of the barrel port (7) and the internal pressure of the gallery chamber (8) rise and exceed the set pressure of the check valve (21), the check valve (21) is closed and the fuel intake passage (30) Prevent backflow of fuel to Further, in the pressure regulating valve (23) on the fuel outlet (22) side, from the state where both the inner valve (49) and the outer valve (48) shown in FIG. 8 are closed, the inner valve (49) shown in FIG. The valve is opened and the outer valve (48) is closed.By opening the inner valve (49), the pressure rise is suppressed to the extent that the delivery valve does not open, and the outer valve (48) is kept closed. Since the fuel flow passage area is narrowed, a certain amount of high pressure is maintained in the barrel ports (7), (7) and the gallery chamber (8). As a result, the flow rate of the backflow flowing from the pump chamber (3) to the gallery chamber (8) immediately before the plunger (6) closes the barrel ports (7), (7) is very high, but the barrel port (7) ( 7) The internal pressure and the gallery chamber (8) are maintained at a positive pressure, and almost no bubbles are generated in the barrel ports (7) and (7) and the gallery chamber (8).
[0039]
The plunger (6) closes the barrel ports (7) and (7), and the fuel in the pump chamber (3) is pumped to the fuel injection valve via the delivery oil passage (5) in the valve holder (4). Then, the needle valve in the fuel injection valve opens and fuel is injected. At the end of injection, the fuel is spilled into the barrel ports (7), (7) and the gallery chamber (8) through the delivery oil passage (5) and the pump chamber (3) due to the extremely high pressure in the injection pipe. Thus, the pressure in the barrel ports (7) and (7) and the gallery chamber (8) rises rapidly. At this time, since there are almost no bubbles in the barrel ports (7), (7) and the gallery room (8), cavitation erosion does not occur.
[0040]
Further, in the pressure regulating valve (23) on the fuel outlet (22) side, both the inner valve (49) and the outer valve (48) shown in FIG. The fuel in the chamber (8) is rapidly discharged from the fuel discharge passage (47). As a result, the internal pressure of the gallery chamber (8), the internal pressure of the barrel ports (7) and (7) and the internal pressure of the pump chamber (3) are rapidly reduced, the internal pressure of the injection pipe is quickly reduced, and the injection of the needle valve in the fuel injection valve is also completed. At the same time, since the valve is quickly closed once, deterioration of combustion performance due to an increase in the injection amount during the valve closing operation can be avoided. Further, the durability of the O-rings (59) and (63) can be ensured.
[0041]
【The invention's effect】
As is clear from the above description, according to the present invention, since the check valve on the fuel inlet side and the pressure regulating valve on the fuel outlet side are incorporated in the pump body, the pump body protrudes greatly from the conventional pump body. Therefore, the size of the pump can be made almost the same as when the pressure adjusting mechanism is not equipped, and space considerations when assembling the pump on the engine side are not required. Moreover, since the pump can be made compact in this way, it contributes to high output and high performance. In addition, since the pump body itself can be used as a valve case, the number of parts can be reduced and the cost can be reduced.
[0042]
In addition, since the lids attached to the valve chambers for storing the check valve and the pressure regulating valve are accommodated in the respective valve chambers, the lids may protrude from the pump body, which may hinder the assembly of the pump to the engine side. There is no such thing as coming.
[0043]
Furthermore, since the lid is composed of a valve seat and a pressing member that presses the valve seat against the step in the valve chamber, and the seal member is attached to the valve seat side, the seal member rotates and deforms or breaks. There is no such a thing. Further, when the seal member is attached outside the screw portion of the pressing member, the pulsation pressure from the gallery chamber acts on the seal member via the screw portion instead of directly, thereby reducing wear of the seal member. be able to. Therefore, in any case, the durability of the seal member can be improved and fuel leakage from each valve chamber can be reliably prevented over a long period of time.
[0044]
Furthermore, by using a two-stage pressure regulating valve whose valve opening pressure and flow passage area change in two stages, it not only prevents cavitation and erosion, but also rapidly in the gallery room when spilling at the end of injection. In addition, the internal pressure of the barrel port and the pump chamber can be reduced to ensure good fuel injection and improve the combustion performance of the engine.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view of a pressure regulating mechanism of a fuel injection pump according to a first embodiment of the present invention.
FIG. 2 is an enlarged longitudinal sectional view of the check valve portion.
FIG. 3 is an enlarged longitudinal sectional view of the pressure regulating valve portion.
FIG. 4 is a longitudinal sectional view of a leak return hole portion.
FIG. 5 is an enlarged longitudinal sectional view of a pressure regulating valve portion according to a second embodiment.
FIG. 6 is an enlarged longitudinal sectional view of a pressure regulating valve portion according to a third embodiment.
FIG. 7 is a longitudinal sectional view of a pressure regulating mechanism according to a fourth embodiment.
FIG. 8 is an enlarged longitudinal sectional view of the pressure regulating valve portion.
FIG. 9 is an enlarged longitudinal sectional view showing the operation of the pressure regulating valve part during backflow.
FIG. 10 is an enlarged vertical sectional view showing the operation of the pressure regulating valve portion during spilling.
FIG. 11 is a longitudinal sectional view of a pressure regulating mechanism of a conventional fuel injection pump.
[Explanation of symbols]
(1) Pump body
(7) Barrel port
(8) Gallery room
(20) Fuel inlet
(21) Check valve
(22) Fuel outlet
(23) Pressure regulating valve
(24) 1st valve chamber
(26) (42) Step
(34) (60) Lid
(35) (61) Valve seat
(36) (62) Holding member
(40) Second valve chamber
(48) Outer valve
(49) Inner valve
(59) Seal member

Claims (4)

Fuel from the fuel inlet formed in the pump body is supplied to the gallery chamber communicating with the barrel port via a check valve, and the fuel is pumped to the fuel injection valve by a plunger that reciprocates in the pump body. In a pressure regulating mechanism of a fuel injection pump that discharges fuel in a chamber from a fuel outlet formed in the pump body through a pressure regulating valve, a check valve is provided in a first valve chamber formed on a fuel inlet side of the pump body. Is slidably housed, and a pressure regulating valve is slidably housed in a second valve chamber formed on the fuel outlet side of the pump body, and the check valve and pressure regulating valve are incorporated in the pump body. Further, the pressure control mechanism of the fuel injection pump, wherein the plunger slides in the sliding direction of the check valve accommodated in the first valve chamber and the sliding direction of the pressure regulation valve accommodated in the second valve chamber. Direction Pressure regulating mechanism of the fuel injection pump, characterized in that arranged along the. The pressure regulating mechanism for a fuel injection pump according to claim 1, wherein a lid for closing each valve chamber is attached so as to be accommodated in each valve chamber.   The lid body includes a valve seat on which each valve is seated, and a pressing member that is screwed into each valve chamber so as to press the valve seat against a step formed in each valve chamber. The pressure regulating mechanism of a fuel injection pump according to claim 2, wherein a seal member is attached to the member.   The pressure regulating valve includes an outer valve in which a valve opening pressure and a flow path area are set to be large, and an inner valve in which the valve opening pressure and the flow path area are set to be small in the outer valve. Item 4. A pressure regulating mechanism for a fuel injection pump according to any one of Items 1 to 3.

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