JP2019105273A - Pressure pulsation reduction mechanism for fuel and high pressure fuel supply pump of internal combustion engine including the same - Google Patents

Abstract

To reduce the number of components in work for assembling a metal diaphragm damper into a low pressure fuel passage, and prevent component deficiency or misassembly.SOLUTION: A pressure pulsation reduction mechanism includes a pair of metal dampers to the whole circumference of which two discoid metal diaphragms are jointed, and in which a sealed space is formed inside the connection section. In the sealed space of the damper, gas is sealed, and at a position inside the connection section, provided is a pair of pressing members configured to impart pressing force to each of both external surfaces of the metal dampers. The pair of pressing members is connected and unified in a state of holding the metal dampers therebetween.SELECTED DRAWING: Figure 7

Description

  The present invention relates to a pressure pulsation reducing mechanism housed in a damper chamber provided in a low pressure fuel passage leading to a pressurizing chamber of a high pressure fuel supply pump.

  The invention also relates to a high pressure fuel supply pump for an internal combustion engine integrally provided with such a pressure pulsation reducing mechanism.

  A conventional fuel pressure pulsation reducing mechanism joins two metal diaphragms and sandwiches a metal damper in which gas is sealed, between a damper chamber provided in a pump body and a cover mounted on the body. It is configured as described above, and is accommodated in a damper chamber formed in the low pressure fuel passage leading to the pressurizing chamber of the high pressure fuel demand pump.

  Specifically, two metal diaphragms are welded on the outer periphery thereof, and have a disk-shaped bulge portion in which a gas is sealed at the center, and two sheets between the weld portion on the outer periphery and the disk-shaped bulge portion It has an annular flat portion in which metal diaphragms overlap. Then, both outer surfaces of the flat plate portion are held between the cover and the thick portion provided on the main body, or between the cover and the annular flat surface portion and the main body and the circular flat surface portion. It has been known.

  In addition, a high pressure fuel supply pump having such a mechanism for reducing pressure pulsation of fuel is also known (Japanese Patent Laid-Open No. 2004-138071, Japanese Patent Laid-Open No. 2006-521487, Japanese Patent Laid-Open No. 2003-254191 and Japanese Patent Laid-Open No. 2003-254191). See 2005-42554).

JP, 2004-138071, A Japanese Patent Application Publication No. 2006-521487 Unexamined-Japanese-Patent No. 2003-254191 JP 2005-42554 A

  In the above-mentioned prior art, it is necessary to simultaneously incorporate and fix many parts in the body at the time of the work of incorporating a metal damper composed of a metal diaphragm as a pressure pulsation reduction mechanism into a low pressure fuel passage or a high pressure fuel supply pump There was a problem that it was easy to cause parts shortage and mispairing.

  An object of the present invention is to reduce the number of parts in the operation of incorporating a metal diaphragm damper as a pressure pulsation reduction mechanism into a low pressure fuel passage, and to prevent part shortage and misassembly.

  Another object of the present invention is to reduce the number of parts when assembling the pressure pulsation reducing mechanism to the high pressure fuel supply pump in the high pressure fuel supply pump provided with the pressure pulsation reducing mechanism, and to prevent part shortage and misassembly. It is in.

  A damper chamber is formed by a pump body and a partition member attached to the pump body, and a low pressure fuel passage for introducing fuel into a pressurizing chamber formed in the pump body through the damper chamber is formed. The housed pressure pulsation reduction mechanism includes a metal damper in which two disk-shaped metal diaphragms are joined all around and a sealed space is formed inside the joint, and the sealed space of the metal damper is filled with gas. And has a pair of pressing members sandwiching the periphery of the metal damper at a position on the inner diameter side of the joint, and the outer circumferential surface of one of the pair of pressing members and the other inner circumferential surface sandwich the metal damper It is a high pressure fuel supply pump unitized by being fitted to each other in the closed state.

  When incorporating a metal diaphragm damper as a pressure pulsation reducing mechanism into a low pressure fuel passage or a high pressure fuel supply pump, it is possible to simultaneously reduce the number of parts incorporated or fixed to the body and prevent part shortage and misassembly.

1 is an example 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 longitudinal 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 the high-pressure fuel supply pump according to the first embodiment of the present invention, and is a longitudinal cross-sectional view of the 90 ° rotated position of FIG. 2; FIG. 1 shows an example of a fuel supply system using a high pressure fuel supply pump according to a first embodiment of the present invention, and in particular shows the flow of fuel in the high pressure fuel supply pump in detail. FIG. 6 is a view showing a generation mechanism of suction pressure pulsation generated by the high pressure fuel supply pump according to the first embodiment of the present invention. It is a figure showing the relation between the suction pressure pulsation generated by the high-pressure fuel supply pump by the first example in which the present invention was carried out, and the area of small diameter part 2a of plunger 2. (A), (b) is a longitudinal cross-sectional view of the high-pressure fuel supply pump according to the first embodiment of the present invention, and in particular, an enlarged view (a) and a perspective view of a portion related to the metal diaphragm damper 9 (B). (A), (b) is a longitudinal cross-sectional view of the high-pressure fuel supply pump according to the first embodiment of the present invention, and shows a cross section perpendicular to FIG. They are an enlarged view (a) and a perspective view (b) of. It is a figure which shows the damper unit 118 at the time of assembling the high pressure fuel supply pump by 1st Example in which this invention was implemented, and the method of assembling it to the pump housing 1 and the damper cover 14. FIG. FIG. 5 is an example of a system diagram of a high pressure fuel supply pump according to a second embodiment in which the present invention is implemented, showing in particular the flow of fuel in the high pressure fuel supply pump. It is a longitudinal cross-sectional view of the high pressure fuel supply pump by 2nd Example by which this invention was implemented. It is a longitudinal cross-sectional view of the high pressure fuel supply pump by 3rd Example by which this invention was implemented, and is an enlarged view of metal diaphragm damper 9 part periphery. It is a longitudinal cross-sectional view of the high pressure fuel supply pump by 4th Example by which this invention was implemented, and is an enlarged view of metal diaphragm damper 9 part periphery.

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

  A first embodiment of the present invention will be described.

  First, the basic operation of the high pressure fuel pump will be described with reference to FIGS. 1 to 3.

  FIG. 1 shows a fuel supply system including a high pressure fuel supply pump.

  FIG. 2 shows a longitudinal sectional view of the high pressure fuel supply pump.

  FIG. 3 shows a longitudinal sectional view in the direction perpendicular to FIG.

  In FIG. 1, the portion enclosed by a broken line shows the pump housing 1 of the high pressure pump, and the mechanism and components shown in the broken line show that they are integrated into the pump housing 1 of the high pressure pump. .

  Fuel in the fuel tank 20 is pumped up by a feed pump 21 based on a signal from an engine control unit 27 (hereinafter referred to as ECU), pressurized to an appropriate feed pressure, and passed through a suction pipe 28 to a suction port 10a of a high pressure fuel supply pump. Sent to

  The fuel having passed through the suction port 10a passes through the filter 102 fixed in the suction joint 101, and further, the metal diaphragm damper 9 and the electromagnetic suction valve mechanism 30 of the electromagnetic suction valve mechanism 30 constituting the variable capacity mechanism via the suction flow paths 10b and 10c. It leads to the suction port 30a.

  The suction filter 102 in the suction joint 101 serves to prevent foreign matter present between the fuel tank 20 and the suction port 10a from being absorbed by the flow of fuel into the high pressure fuel supply pump.

  The details of the metal diaphragm damper 9 for reducing pressure pulsation will be described later.

  The electromagnetic suction valve mechanism 30 includes an electromagnetic coil 30b, and in a state where the electromagnetic coil 30b is energized, the compressed state of the spring 33 is maintained with the electromagnetic plunger 30c moved to the right in FIG.

  At this time, the suction valve body 31 attached to the tip of the electromagnetic plunger 30c opens the suction port 32 connected to the pressurizing chamber 11 of the high pressure pump.

  When the electromagnetic coil 30 b is not energized and there is no fluid pressure difference between the suction flow path 10 c (suction port 30 a) and the pressure chamber 11, the biasing force of the spring 33 causes the suction valve body 31 to Is biased in the valve closing direction, and the suction port 32 is in the closed state.

  When the plunger 2 is in the suction process state in which the plunger 2 is displaced downward in FIG. 2 by the rotation of a cam described later, the volume of the pressure chamber 11 increases and the fuel pressure in the pressure chamber 11 decreases. When the fuel pressure in the pressurizing chamber 11 becomes lower than the pressure in the suction flow path 10c (suction port 30a) in this process, the valve opening force (the suction valve body 31) is determined by the fluid pressure difference of the fuel. The force to displace to the right of 1) is generated.

  The suction valve body 31 is set to open by opening the suction port 32 by overcoming the biasing force of the spring 33 by the valve opening force by the fluid differential pressure.

In this state, when a control signal from the ECU 27 is applied to the electromagnetic suction valve mechanism 30, a current flows through the electromagnetic coil 30b of the electromagnetic suction valve mechanism 30, and the magnetic biasing force generated thereby generates the electromagnetic plunger 30c shown in FIG. And the spring 33 is maintained in a compressed state.
As a result, the state where the suction valve body 31 opens the suction port 32 is maintained.

  When the plunger 2 ends the suction process while maintaining the applied state of the input voltage to the electromagnetic suction valve mechanism 30 and moves to the compression process in which the plunger 2 is displaced upward in FIG. 2, the magnetic biasing force is maintained. Still, the suction valve body 31 remains open.

  The volume of the pressure chamber 11 decreases with the compression movement of the plunger 2. In this state, the fuel once sucked into the pressure chamber 11 passes through the suction valve body 31 in the open state again to the suction passage 10c ( As pressure is returned to the suction port 30a), the pressure in the pressure chamber does not rise. This process is called a return process.

  In this state, when the control signal from the ECU 27 is released to de-energize the electromagnetic coil 30b, the magnetic biasing force acting on the electromagnetic plunger 30c is after a predetermined time (after the magnetic and mechanical delay time). It is erased. Since the biasing force of the spring 33 acts on the suction valve body 31, when the electromagnetic force acting on the electromagnetic plunger 30c disappears, the suction valve body 31 closes the suction port 32 by the biasing force of the spring 33. From this time on, when the suction port 32 is closed, the fuel pressure in the pressure chamber 11 rises with the upward movement of the plunger 2. Then, when the pressure of the fuel discharge port 12 becomes equal to or higher, high pressure discharge of the fuel remaining in the pressurizing chamber 11 is performed via the discharge valve unit 8, and is supplied to the common rail 23. This process is called a discharge process. That is, the compression process (the rising process from the lower start point to the upper start point) of the plunger 2 includes the return process and the discharge process.

  Then, the amount of high-pressure fuel to be discharged can be controlled by controlling the timing at which the electromagnetic coil 30c of the electromagnetic suction valve mechanism 30 is deenergized.

  If the timing for releasing the energization of the electromagnetic coil 30c is advanced, the ratio of the return process is small during the compression process, and the ratio of the discharge process is large.

  That is, the amount of fuel returned to the suction flow passage 10c (the suction port 30a) is small, and the amount of fuel discharged at high pressure is large.

  On the other hand, if the timing for releasing the input voltage is delayed, the proportion of the return step in the compression step is large, and the proportion of the discharge step is small. That is, the amount of fuel returned to the suction passage 10c is large, and the amount of fuel discharged at high pressure is small. The timing at which the energization of the electromagnetic coil 30c is released is controlled by a command from the ECU.

  By configuring as described above, the amount of fuel to be discharged at high pressure can be controlled to the amount required by the internal combustion engine by controlling the timing of releasing the energization of the electromagnetic coil 30c.

  Thus, the fuel introduced into the fuel suction port 10a is introduced into the pressure chamber 11 of the pump housing 1 and the necessary amount is pressurized to a high pressure by the reciprocating motion of the plunger 2 and is pressure-fed from the fuel discharge port 12 to the common rail 23. .

  An injector 24 and a pressure sensor 26 are mounted on the common rail 23. The injectors 24 are mounted in accordance with the number of cylinders of the internal combustion engine, and open and close valves in accordance with a control signal of the engine control unit (ECU) 27 to inject fuel into the cylinders.

  A convex portion 1A as a pressure chamber 11 is formed in the center of the pump housing 1, and a recess 11A for mounting the discharge valve mechanism 8 is formed between the inner peripheral wall of the pressure chamber 11 and the discharge port 12 ing. Furthermore, a hole 30A for mounting the electromagnetic suction valve mechanism 30 for supplying fuel to the pressurizing chamber 11 is provided on the outer wall of the pump housing coaxially with the recess 11A for mounting the discharge valve mechanism 8. .

  With respect to the central axis of the recess 1A as the pressure chamber 11, the recess 11A for mounting the discharge valve mechanism 8 and the axis of the hole for mounting the electromagnetic suction valve mechanism 30 are formed in the intersecting direction. A discharge valve mechanism 8 for discharging the fuel from 11 to the discharge passage is provided.

  In addition, a cylinder 6 for guiding the reciprocating motion of the plunger 2 is attached so as to face the pressure chamber.

  In the first embodiment, the recess 11A for mounting the discharge valve mechanism 8 and the axis of the hole 30A for mounting the electromagnetic suction valve mechanism 30 are formed to be the same axis. The hole 30A for mounting the mechanism 30 can be assembled straight into the mounting recess 11A of the discharge valve mechanism 8. Alternatively, the force for press-fitting the discharge valve mechanism 8 can be applied from the hole 30A for mounting the electromagnetic suction valve mechanism 30. In this case, the diameter of the hole 30A needs to be larger than the maximum outside diameter of the discharge valve mechanism 8 at the minimum diameter portion.

  A discharge valve mechanism 8 is provided at the outlet of the pressure chamber 11. The discharge valve mechanism 8 comprises a seat member (seat member) 8a, a discharge valve 8b, a discharge valve spring 8c, and a holding member 8d as a discharge valve stopper.

  In the state where there is no differential pressure of fuel between the pressure chamber 11 and the discharge port 12, the discharge valve 8b is crimped to the sheet member 8a by the biasing force of the discharge valve spring 8c and is in a closed state. The discharge valve 8b opens against the discharge valve spring 8c only when the fuel pressure in the pressure chamber 11 becomes larger than the fuel pressure in the discharge port 12 by a predetermined value. The fuel is discharged to the common rail 23 through the discharge port 12.

  When the discharge valve 8 b is opened, the discharge valve 8 b contacts the holding member 8 d and the operation is restricted. Therefore, the stroke of the discharge valve 8b is appropriately determined by the holding member 8d. If the stroke is too large, the fuel discharged to the fuel discharge port 12 will flow back again into the pressurizing chamber 11 due to the delay in closing the discharge valve 8b, so the efficiency as a high pressure pump will decrease. . Further, when the discharge valve 8b repeats opening and closing motions, the discharge valve 8b is guided by the holding member 8d so as to move only in the stroke direction. By comprising as mentioned above, discharge valve mechanism 8 serves as a nonreturn valve which restricts the distribution direction of fuel.

  Further, the high pressure fuel supply pump is fixed to the engine by the flange holder 40, the flange 41 and the bush 43. The flange holder 40 is crimped to the engine by the set screw 42 via the flange 41. A bush 43 is present between the flange 41 and the engine. Since the flange holder 40 is fixed to the pump housing 1 by a screw screwed to the inner periphery, the pump housing is thereby fixed to the engine.

  Although the bush 43 is fixed to the flange 41, the flange 41 can be made into a flat shape without a curved portion as shown in FIG. This facilitates the formation of the flange 41.

  The pump housing 1 is further provided with a relief passage 311 communicating the downstream side of the discharge valve 8b with the suction passage 10c.

  The relief passage 311 is provided with a relief valve mechanism 200 which restricts the flow of fuel in only one direction from the discharge passage to the suction passage 10c, and the inlet of the relief valve mechanism 200 is a discharge valve 8b by a passage not shown. It communicates with the downstream side of the

  The operation of the relief valve mechanism 200 will be described below. The relief valve 202 is pressed against the relief valve seat 201 by a relief spring 204 that generates a pressing force, and when the pressure difference between the suction chamber and the inside of the relief passage exceeds a prescribed pressure, the relief valve 202 is a relief valve seat. The set valve opening pressure is set so as to open the valve apart from 201. Here, the pressure at which the relief valve 202 starts to open is defined as the set valve opening pressure.

  The relief valve mechanism 200 includes a relief valve housing 206 integrated with the relief valve seat 201, a relief valve 202, a relief press 203, a relief spring 204, and a relief spring adjuster 205. The relief valve mechanism 200 is assembled outside the pump housing 1 as a subassembly, and thereafter fixed to the pump housing 1 by press fitting.

  First, the relief valve 202, the relief press 203, and the relief spring 204 are sequentially inserted into the relief valve housing 206 in order, and the relief spring adjuster 205 is press-fitted and fixed to the relief valve housing 206. The set position of the relief spring 204 is determined by the fixed position of the relief spring adjuster 205. The valve opening pressure of the relief valve 202 is determined by the set load of the relief spring 204. The relief subassembly 200 thus produced is press-fitted and fixed to the pump housing 1.

  In this case, the opening pressure of the relief valve 200 is set to a pressure higher than the maximum pressure in the normal operating range of the high pressure fuel supply pump.

  When the abnormally high pressure in the common rail 23 caused by the failure of the fuel injection valve that supplies fuel to the engine, or the failure of the ECU 27 that controls the fuel injection valve, high-pressure fuel supply pump, etc. becomes equal to or higher than the set valve opening pressure of the relief valve. The fuel flows from the downstream side of the discharge valve 8 b through the relief flow passage 211 and reaches the relief valve 202. Then, the fuel that has passed through the relief valve 202 is opened to the suction passage 10 c which is a low pressure portion of the relief passage 208 opened in the relief spring adjuster 205. As a result, the high pressure part such as the common rail 23 is protected.

  The outer periphery of the cylinder 6 is held by the cylinder holder 7, and the cylinder holder 7 is held inside the flange holder 40. The cylinder 6 is fixed to the pump housing 1 via the cylinder holder 7 by screwing a screw 410 screwed on the inner periphery of the flange holder 40 into a screw 411 screwed on the pump housing 1. The cylinder 6 slidably holds the plunger 2 advancing and retracting in the pressure chamber 11 along the advancing and retracting direction.

  At the lower end of the plunger 2 is provided a tappet 3 which converts the rotational movement of the cam 5 attached to the camshaft of the engine into vertical movement and transmits it to the plunger 2. The plunger 2 is crimped to the tappet 3 by a spring 4 through a retainer 15. The retainer 15 is fixed to the plunger 2 by press fitting. As a result, the plunger 2 can be moved up and down (reciprocated) up and down with the rotational movement of the cam 5.

  Further, the plunger seal 13 held at the lower end portion of the inner periphery of the cylinder holder 7 is installed in a state where it can slidably contact the outer periphery of the plunger 2 at the lower end portion in the drawing of the cylinder 6 This prevents the fuel from flowing into the tappet 3 side, that is, the inside of the engine. At the same time, lubricating oil (including engine oil) for lubricating the sliding portion in the engine room is prevented from flowing into the inside of the pump housing 1.

  Here, the suction passage 10c is connected to the seal chamber 10f via the suction passage 10d and the suction passage 10e provided in the cylinder 6, and the seal chamber 10f is always connected to the pressure of the suctioned fuel. There is. When the fuel in the pressurizing chamber 11 is pressurized to a high pressure, minute high-pressure fuel flows into the seal chamber 10f through the sliding clearance between the cylinder 6 and the plunger 2, but the inflowing high-pressure fuel is released to the suction pressure As a result, the plunger seal 13 is not damaged by high pressure.

  Further, the plunger 2 includes a large diameter portion 2 a sliding on the cylinder 6 and a small diameter portion 2 b sliding on the plunger seal 13. The diameter of the large diameter portion 2a is set to be larger than the diameter of the small diameter portion 2b, and is set to be coaxial with each other. In the case of the present embodiment, the diameter of the large diameter portion 2a is set to 10 mm, and the diameter of the small diameter portion 2b is set to 6 mm. By doing this, it is possible to reduce the pressure pulsation on the low pressure side generated on the low pressure side upstream of the electromagnetic intake valve mechanism 30 with the vertical movement of the plunger.

  Hereinafter, a mechanism for reducing pressure pulsation on the low pressure side by configuring the plunger 2 by the large diameter portion 2a and the small diameter portion 2b will be described with reference to FIG. 4, FIG. 5, and FIG.

  FIG. 4 is a system diagram of the high pressure fuel supply pump in the present embodiment.

  FIG. 5 shows the relationship between the movement of the plunger 2 and the movement of the fuel inside the high pressure fuel supply pump.

  FIG. 6 shows the relationship between the area ratio of the large diameter portion 2 a and the small diameter portion 2 b of the plunger 2 and the pressure pulsation generated in the low pressure pipe 28.

  FIG. 4 shows the flow of fuel inside the high pressure fuel supply pump in the present embodiment. The fuel that has flowed into the high pressure fuel supply pump from the suction port 10a passes through the metal damper 9 (3), and a part of the fuel flows from the suction passage 10c into the pressurizing chamber 11 through the suction valve body 31 (1) The remaining part flows from the suction passage 10c into the seal chamber 10f via the suction passage 10d (2). That is, the relationship of the fuel flowing inside the high pressure fuel supply pump is as follows.

(3) = (1) + (2)
Here, the flow of fuel is positive with the direction of the arrow in FIG. When the value is negative, it means that the fuel flows in the opposite direction to the arrow.

  FIG. 5 shows the relationship between the movement of the plunger 2 and the flow of fuel (1) (2) (3).

  The top table shows the movement of the plunger, TDC (abbreviation of TOP DEAD CENTER) is when the position of plunger 2 comes to the top in FIG. 2, BDC (abbreviation of BOTTOM DEAD CENTER) is that of plunger 2 It shows when the position came to the bottom. As described above, the plunger 2 comprises the suction step during the downward movement and the return step and the discharge step during the upward movement.

  Furthermore, the lower figure shows the fuel flow (1) (2) (3).

In the drawing, “S” is a ratio of “the cross sectional area of the small diameter portion 2 b” in the plunger 2 to the “cross sectional area of the large diameter portion 2 a”. In the case of this embodiment, the diameter of the large diameter portion 2a is 10 mm, and the diameter of the small diameter portion 2b is 6 mm.
S = 6 ^ 2/10 ^ 2
It is 0.36.

Next, the situation in each process of the fuel flow (1) (2) (3) will be described.
Intake Step (1) The volume of the pressure chamber 11 is increased by the downward movement of the plunger 2, and the fuel corresponding to the volume increase flows from the suction passage 10c. The volume increase amount in this case is generated by the large diameter portion 2a, and the increase at this time is set to one. Therefore, the amount of fuel flow is 1 in the table.

(2) Since the lower end of the large diameter portion 2a is lowered into the seal chamber 10f by the downward movement of the plunger 2, the volume of the seal chamber 10f decreases, and the fuel corresponding to this volume decrease flows back from the seal chamber 10f. Then, it flows out to the suction flow path 10c. The volume reduction in this case is
It becomes 1-S, and the flow of fuel also considers the direction
It becomes-(1-S).

(3) The sum of the above (1) and (2) becomes the fuel (3) flowing from the suction port 10a to the suction flow path 10c inside the high pressure fuel supply pump,
The fuel of 1 + [-(1-S)] = S will flow into the high pressure fuel supply pump.

Returning Step (1) The volume of the pressure chamber 11 is reduced by the upward movement of the plunger 2, and the volume-reduced fuel flows out to the suction passage 10c. Similar to the suction process, the volume reduction amount in this case is generated by the large diameter portion 2a, and the weight reduction at this time is made 1. Therefore, the amount of fuel flow is -1 in the table.

(2) As the lower end of the large diameter portion 2a rises inside the seal chamber 10f by the upward movement of the plunger 2, the volume of the seal chamber 10f increases, and fuel corresponding to this volume increase flows from the seal chamber 10f to the suction passage It flows into 10c. The volume increase in this case is
1-S, the flow of fuel is
It becomes 1-S.

(3) The fuel (3) flowing from the suction port 10a to the suction flow path 10c is
It becomes [-1] + [(1-S)] = -S.

Discharge Process (1) The volume of the pressure chamber 11 is reduced by the upward movement of the plunger 2, and the fuel in the pressure chamber 11 is pressurized to a high pressure. Then, the fuel is supplied to the common rail 23 through the discharge valve mechanism 8 and the fuel discharge port 12. In this case, although the volume in the pressure chamber 11 decreases, no fuel flows between the suction passage 10 c and the pressure chamber 11. Therefore, the amount of fuel flow is zero.

(2) Since the same operation as the above-mentioned return process is performed, the fuel flow is
It becomes 1-S.

(3) The fuel (3) flowing from the suction port 10a to the suction flow path 10c is
It becomes 0 + [(1-S)] = 1-S.

The pressure pulsation generated in the suction flow path 28 between the feed pump 21 and the suction port 10a relates to the "fuel (3) flowing from the suction port 10a into the suction flow path 10c". In the lowermost table of FIG. 8, T indicates the ratio of the discharge step occupied during the raising step of the plunger 2. Then, the ratio of the suction process occupied in the rising process of the plunger 2 is
It becomes 1-T.

          When T = 0, there is no discharge process, and the fuel is not discharged at high pressure.

          When T = 1, there is no return process, and all the fuel flowing into the pressure chamber 11 is pressurized to a high pressure and supplied to the common rail 23. This mode is called full discharge.

The magnitude of the suction pressure pulsation generated in the suction pipe 28 is determined by the sum of the following two amounts.
(A) The total amount of fuel flowing into the suction flow passage 10c from the suction port 10a (b) The total amount of fuel flowing out into the suction flow passage 10a from the suction port 10c Here, (a) is the bottom of FIG. Corresponds to the area of the shaded area in
(A) = [S * 1] + (1-S) T
On the other hand, (b) corresponds to the area of the shaded portion, so
(B) = S (1-T)
Therefore, calculate (c) = (a) + (b)
(C) = (a) + (b) = (1-2S) T + 2S.

FIG. 6 shows the relationship between T and (c) above.
When S = 1, the diameter and the cross-sectional area of the small diameter portion 2 a and the large diameter portion 2 b of the plunger 2 are equal, and there is no step in the plunger 2.

  At this time, when T = 0, that is, when the high pressure discharge is zero, the pressure pulsation generated in the suction pipe 28 is largest. It means that all the fuel that has been once sucked into the pressure chamber 11 is returned to the suction port 10a.

  On the other hand, the suction pressure pulsation becomes smaller as T becomes larger. This indicates that the fuel in the pressure chamber 11 is discharged to the common rail 23 at a high pressure in the discharge step, so the amount of fuel returned to the suction port 10a is reduced accordingly.

  When S = 0, the cross-sectional area of the small diameter portion 2a of the plunger 2 is 0, which is a state that can not occur in practice.

  At T = 0, suction pressure pulsations do not occur. This indicates that the fuel is merely going back and forth between the pressurizing chamber 11 and the seal chamber 10f, and no fuel is going between the suction port 10a and the suction passage 10c.

  As T increases, the pressure pulsation increases. In the discharge step, the fuel is discharged from the pressurizing chamber 11 to the common rail 23 at a high pressure, and at the same time, the fuel flows into the suction passage 10c from the suction port 10a in order to suck the fuel also into the seal chamber 10f.

  When S = 0.5, it indicates that the low pressure pulsation is constant regardless of the value of T.

From the above, it is desirable that S be as small as possible.
However, to make S smaller means to make the small diameter portion 2b of the plunger 2 thinner, and if it is made too thin, the strength of the small diameter portion 2a will be insufficient and the plunger 2 will be broken.

  In the present embodiment, as described above, the diameter of the large diameter portion 2a is 10 mm, the diameter of the small diameter portion 2b is 6 mm, and S = 0.36. The characteristic at S = 0.36 is shown in FIG.

  Thus, it is understood that the low pressure pulsation can be reduced compared to the case of S = 1 after securing the strength of the small diameter portion 2b.

  Next, a metal diaphragm damper 9 for absorbing pressure pulsations to reduce low pressure pulsations generated by the above mechanism and a method of fixing the same will be described.

  FIG. 7 is an enlarged view and a perspective view of the metal diaphragm damper 9 for absorbing pressure pulsations in FIG.

  FIG. 8 is an enlarged view and a perspective view of the metal diaphragm damper 9 for absorbing pressure pulsations in FIG.

  FIG. 9 shows an assembly procedure for fixing the damper unit 118 to the pump housing 1.

  The damper unit 118 is composed of two metal diaphragms 9a and 9b, and the outer periphery of the damper unit 118 is fixed to each other by welding around the welding portion 9d while the gas 9c is enclosed in the space between both diaphragms. A flat portion exists inside the welded portion 9d, and by sandwiching this portion, the flat portion is installed in the low pressure passage of the high pressure fuel supply pump to form and fix the suction flow passages 10b and 10c.

  When low pressure pressure pulsations are loaded on both sides of the metal diaphragm damper 9, the metal diaphragm damper 9 changes its volume, thereby reducing the low pressure pressure pulsation.

  The metal diaphragm damper 9 is vertically sandwiched by the upper clamping member 104 and the lower clamping member 105, and at the time of assembly, as shown in FIG.

  The upper holding member 104 has a curled portion 119, and the upper end of the lower holding member 105 faces the curled portion 119 to hold the flat portion of the metal diaphragm damper 9. The contact portions of the upper holding member 104 and the metal diaphragm damper 9 and the contact portions of the lower holding member 105 and the metal diaphragm damper 9 have the same diameter, and are in contact over the entire circumference.

  The inner peripheral portion 110 of the upper holding member 104 and the outer peripheral portion 111 of the lower holding member 105 are fixed by pressure, and are fixed to each other at a peripheral portion outside the metal diaphragm damper 9. The welded portion 9 d of the metal diaphragm damper 9 is disposed in the space 107 formed between the lower holding members 105.

  With such a configuration, the metal diaphragm damper 9 can be fixed without generating stress in the welded portion 9 d of the metal diaphragm damper 9.

  In addition, since it is held by being vertically symmetrical across the entire circumference and fixed, no stress is generated by the fixing other than the fixing portion.

  Further, the radial positioning of the three members of the upper and lower holding members 104 and 105 and the metal diaphragm damper 9 is easily performed by the inner peripheral portion 110 of the upper holding member 104.

  The damper unit 118 configured as described above is accommodated in the recess formed in the pump housing 1. At this time, although the positioning in the radial direction is performed between the outer peripheral portion 116 of the upper holding member 104 and the inner peripheral portion 117 of the pump housing 1, it is not a press fit but a gap.

  In this state, the damper cover 14 is further assembled from above.

  The damper cover 14 is formed in a cup shape, and the open annular end surface thereof is welded and fixed to the pump housing 1 by welding 106.

  The damper cover 14 has a protrusion 120 projecting inward, and the upper holding member 104 is in contact with the damper cover 14 at the contact portion 114. The projecting portion 120 is an annular projecting shape having a partially missing damper cover dropout portion 112, and the damper cover 14 and the damper unit 118 are not in contact with each other at the damper cover dropout portion 112.

  The concave end surface 115 of the pump housing 1 is in contact with the lower holding member 105 and has an annular structure with a part missing due to the body missing part 113 with a part missing. And the damper unit 118 are not in contact with each other. The body missing portion 113 also lacks the inner circumferential portion 117, and the missing portion 113 does not contribute to the positioning of the upper clamping member 104 with the outer circumferential portion 116.

  Further, the damper unit 118 is fixed so as to hold the upper holding member 104 from the upper side by the damper cover 14 and hold the lower holding member 105 from the lower side. This is to fix the upper clamping member 104 and the lower clamping member 105 in a direction to promote press-fitting.

  As a result, the press fit of the upper sandwiching member 104 and the lower sandwiching member 105 is loosened by the pressure pulsation of the fuel, the vibration of the engine or the like, and the fixation of the metal diaphragm damper 9 is not loosened.

  The suction passage 10 b between the damper cover 14 and the metal diaphragm damper 9 is in communication with the annular space 121 between the damper cover 14 and the upper holding member 104 by the damper cover missing portion 112. The suction passage 10 c between the pump housing 1 and the metal diaphragm damper 9 is also in communication with the annular space 121 between the damper cover 14 and the upper holding member 104 by the body missing portion 113.

  As a result, the damper unit 118 is held in a state of being sandwiched between the damper cover 14 and the pump housing 1, and at the same time, the suction flow path 10 b and the suction flow path 10 c are communicated. The fuel flowing from the suction port 10a into the high pressure fuel supply pump flows to the suction flow path 10b and then to the suction flow path 10c, so all the fuel flow (3) in FIG. 4 passes through the metal diaphragm damper 9. As a result, the fuel spreads on both sides of the metal diaphragm damper 9, and the fuel pressure pulsation can be efficiently reduced by the metal diaphragm damper 9.

  The damper cover 14 is formed by pressing a rolled steel plate and processed, and therefore, the thickness of the cover is uniform everywhere. When fixing to the pump housing 1, first, the damper cover 14 is temporarily pressed into and fixed to the pump housing 1 by the press-fit portion 122. At this time, the protrusion 120 of the damper cover 14 and the upper clamping member 104 have already made contact with the contact portion 114, and the concave end surface 115 of the pump housing 1 and the lower clamping member 105 are in contact. Is rigidly fixed by being sandwiched between the pump housing 1 and the damper cover 14.

  In this state, the press-fit portion 122 is welded and fixed in a fluid-tight manner over the entire circumference so as to pierce the damper cover 14 at the weld portion 106. As a result, the inside and outside of the high pressure fuel supply pump are completely sealed in a fluid tight manner at the weld portion 106, and the fuel is sealed from the outside.

  The damper cover 14 displaces the damper unit 118 in the direction of pressing the damper unit 118 with the pump housing 1 and the damper cover 14 by thermal strain generated after welding, so that the clamping force of the damper unit 118 is not attenuated even after welding.

  Further, as shown in FIG. 3, the outer diameter of the relief valve housing 206 is press-fitted and fixed to the pump housing 1. The press-fit load is set to such an interference that the relief valve housing 206 does not come off in the upper side in the figure by the high pressure fuel in the relief flow passage 211.

  However, even if the relief valve housing 206 is pulled upward in the figure by high pressure fuel due to some mistake, the relief valve housing 206 and the lower holding member 105 first contact each other, and there is a mechanism for preventing the detachment.

  Specifically, the relief flow passage 211, which is a hole into which the relief valve housing 206 is press-fitted, has a positional relationship such that the relief flow passage 211 overlaps the recessed end surface 115 of the pump housing 1. The valve mechanism 200 is press-fitted and fixed to the relief channel 211. At this time, the upper end surface of the relief valve housing 206 is press-fitted and fixed so that the upper end surface is lower than the concave end surface 115 of the pump housing 1.

  With such a configuration, the relief valve housing 206 and the lower holding member 105 first contact each other even if the relief valve housing 206 is removed by the high pressure fuel.

  Further, in the present embodiment, the suction joint 101 is fixed to the damper cover dropout portion 112 of the damper cover 14 by the weld portion 103. The filter 102 is fixed to the suction joint 10a. The suction port 10 a is formed in the suction joint 101. All fuel flowing into the high pressure fuel supply pump will pass through this filter.

  Next, a second embodiment of the present invention will be described.

  The difference between the second embodiment and the first embodiment is only the position of the suction joint 101. The other parts are the same as in the first embodiment, and all the symbols and numerals described are common to the first embodiment.

  FIG. 10 shows a system diagram of the high pressure fuel supply pump in the present embodiment.

  FIG. 11 shows a longitudinal sectional view of the high pressure fuel supply pump in the present embodiment.

  The suction joint 101 is attached to the pump housing 1 and fixed by a weld 103.

  The suction port 10 a is formed in the suction joint 101, and the filter 102 is fixed in the suction joint 101. All fuel flowing into the high pressure fuel supply pump will pass through this filter 102.

The suction port 10a is connected to the suction flow path 10d, and the low pressure fuel entering the high pressure fuel supply pump from the suction port 10a passes through the filter 102 and is first led to the suction flow path 10d (3).
From there, it divides into fuel (1) which goes to pressurization room 11 through suction channel 10b2 and 10c, and fuel (2) which goes to seal room 10f. Therefore, also in this case, the following relationship is established.

          (3) = (1) + (2)

  In the present embodiment, the metal diaphragm damper 9 is present between the pressure chamber 11 and the suction passage 10d. In this case, the metal diaphragm damper 9 mainly absorbs and reduces pressure pulsation generated in the fuel (1) traveling from the suction flow passage 10d to the pressurizing chamber 11.

  The suction flow passage 10 b 2 and the suction flow passage 10 c communicate with each other through the annular space 121 as in the first embodiment. As a result, the fuel is sufficiently spread on both sides of the metal diaphragm damper 9, so that the pressure pulsation can be sufficiently reduced.

  According to the first embodiment and the second embodiment, the position of the suction joint can be appropriately selected according to the layout of each engine. Even in this case, the size and weight of the high-pressure fuel supply pump can be kept small and light without increasing in size and weight.

  Next, a third embodiment of the present invention will be described.

  The difference between the third embodiment and the first embodiment is only the protruding length 123 of the lower holding member 105 from the upper holding member 104. The other parts are the same as in the first embodiment, and all the symbols and numerals described are common to the first embodiment.

  FIG. 12 is a longitudinal cross-sectional view of the high pressure fuel supply pump in the present embodiment, and is an enlarged view of the metal diaphragm damper 9 for absorbing pressure pulsations.

  In the present embodiment, the lower holding member 105 projects lower than the upper holding member 104 in the figure as in the first embodiment. And let the protrusion amount be 123.

  The upper holding member 104 is in contact with the damper cover 14 and the lower holding member 105 is in contact with the pump housing 1 as in the first embodiment.

In the present embodiment, the amount of protrusion 123 is set as small as 0.5 mm or less.
By doing this, since the press-fit portions of the upper clamping member 104 and the lower clamping member 105 can be set long enough, when the damper unit 118 is fixed between the damper cover 14 and the pump housing 1, Even if variations (individual differences) occur in the force, they can be absorbed, and variations in the force with which the upper holding member 104 and the lower holding member 105 hold the metal diaphragm damper 9 can be reduced.

  The damper cover 14 is displaced in the direction to press the damper unit 118 between the pump housing 1 and the damper cover 14 due to the thermal strain generated after welding the damper cover 14 to the pump housing 1, but variations (individual differences) also occur in this displacement. .

  By adopting the structure as in this embodiment, it is possible to reduce the variation in the force with which the upper clamping member 104 and the lower clamping member 105 fix the metal diaphragm damper 9 caused by the variation (individual difference) of the displacement. .

  Next, a fourth embodiment of the present invention will be described.

  The difference between the fourth embodiment and the first embodiment is that the concave end surface 115 of the pump housing 1 is in contact with the lower end portion 124 of the upper holding member 104, and the pump housing 1 and the lower holding member 105 are not in contact. . The other parts are the same as in the first embodiment, and all the symbols and numerals described are common to the first embodiment.

  FIG. 13 is a vertical cross-sectional view of the high-pressure fuel supply pump in the present embodiment, and is an enlarged view of the metal diaphragm damper 9 for absorbing pressure pulsations.

  The damper cover 14 and the upper holding member 104 are in contact at the contact portion 114. On the other hand, the concave end surface 115 of the pump housing 1 and the lower end portion 124 of the upper holding member 104 are in contact with each other.

  With this structure, the metal diaphragm damper 9 is vertically held only by the mutual pressure input of the upper holding member 104 and the lower holding member 105.

  Therefore, even if the force holding down the damper cover 14 and the damper unit 118 of the pump housing 1 varies due to thermal strain or the like generated after welding, the variation does not change the force sandwiching the metal diaphragm damper 9, and metal Damage to the diaphragm damper 9 can be prevented.

  When the metal diaphragm damper 9 is broken, the pressure pulsation of the fuel in the suction pipe 28 exceeds the allowable value, which leads to damage of the suction pipe 28, fuel leakage and the like.

  Further, when the relief valve housing 206 is pulled upward in the figure by high pressure fuel due to some mistake, the relief valve housing 206 and the upper holding member 104 first contact each other, and there is a mechanism for preventing the pressure valve from coming off.

  Even in this case, there is no change in the force for holding the metal diaphragm damper 9.

  It is as follows when the above Example aspect is arranged.

Embodiment 1
The suction flow path for sucking the fuel into the pressure chamber and the discharge flow path for discharging the fuel from the pressure chamber, and the plunger that reciprocates in the pressure chamber sucks and discharges the fuel, The suction flow path is provided with a suction valve and the discharge flow path is provided with a discharge valve, and pressure pulsation is reduced by changing pressure in the suction flow path or in the low pressure chamber communicating with the suction flow path. A high pressure fuel supply pump comprising a pressure pulsation reducing damper for welding, wherein the pressure pulsation reducing damper is a metal diaphragm damper in which two metal diaphragms are welded at their peripheral portions and gas is sealed therebetween;
The metal diaphragm damper is present in a space formed by a body and a cover, and the cover has a projection projecting inward, and the projection and the body sandwich and fix the metal diaphragm damper. High-pressure fuel supply pump characterized by

Embodiment 2
In the one described in Embodiment 1,
The high pressure fuel supply pump according to claim 1, wherein the projection has an annular projection which is partially missing.

Embodiment 3
In the embodiments described in Embodiment 1 or 2,
By holding the peripheral portion of the metal diaphragm damper up and down with a pair of upper and lower clamping members, the three are unitized as a damper unit in that state, and the projection of the cover and the upper side of the damper unit The metal diaphragm damper is held and fixed by holding the damper unit between the cover and the body in contact with the holding member, and a passage connecting the inside and the outside is provided between the cover and the upper holding member. And a space between the metal diaphragm damper and the cover is communicated between the metal diaphragm damper and the body.

Embodiment 4
The suction flow path for sucking the fuel into the pressure chamber and the discharge flow path for discharging the fuel from the pressure chamber, and the plunger that reciprocates in the pressure chamber sucks and discharges the fuel, The suction flow path is provided with a suction valve and the discharge flow path is provided with a discharge valve, and pressure pulsation is reduced by changing pressure in the suction flow path or in the low pressure chamber communicating with the suction flow path. A high pressure fuel supply pump comprising a pressure pulsation reducing damper for welding, wherein the pressure pulsation reducing damper is a metal diaphragm damper in which two metal diaphragms are welded at their peripheral portions and gas is sealed therebetween;
By holding the peripheral portion of the metal diaphragm damper up and down with a pair of upper and lower clamping members, the three are unitized as a damper unit in that state, and cover the damper unit and hold the upper side of the damper unit In contact with the member, the damper unit is pressed against the body of the high pressure fuel supply pump, and a passage connecting the inside and the outside is provided between the cover and the upper holding member, and the metal diaphragm damper is interposed between the cover and the cover A high pressure fuel supply pump, wherein a space is communicated between the metal diaphragm damper and the body.

Embodiment 5
In the embodiments described in Embodiments 3 to 4,
The high-pressure fuel supply pump characterized in that the upper and lower holding members are in contact with the peripheral portion of the metal diaphragm damper over the entire circumference.

Embodiment 6
In the embodiments described in Embodiments 3 to 4,
A high-pressure fuel supply pump characterized in that the upper and lower holding members are fixed to each other by press-fitting at a peripheral portion outside the metal diaphragm damper to form the damper unit.

Embodiment 7
In the embodiments described in Embodiments 3 to 4,
An annular space is formed between the upper and lower holding members, and a welded portion of the metal diaphragm damper is accommodated in the space.

Embodiment 8
In the embodiments described in Embodiments 3 to 4,
A high-pressure fuel supply pump characterized in that an outer periphery of either one of the upper and lower holding members forms a positioning surface in the radial direction with the body.

Embodiment 9
In the embodiments described in Embodiments 3 to 4,
A high-pressure fuel supply pump characterized in that the upper and lower holding members are fixed to each other by welding at their peripheral portions to form the damper unit.

Embodiment 10
In the embodiments described in Embodiments 3 to 4,
The high pressure fuel supply pump according to claim 1, wherein the upper clamping member contacts the cover, and the lower clamping member contacts the body.

[Embodiment 11]
In the embodiments described in Embodiments 3 to 4,
It has a relief flow passage connecting the high pressure part downstream of the discharge valve and the space formed by the body and the cover, and the flow of fuel in the relief flow passage is high pressure downstream of the discharge valve A high pressure fuel supply pump comprising a limiting valve limiting in one direction from a part into a space formed by the body and the cover;
The high pressure fuel supply pump according to claim 1, wherein the relief flow passage overlaps between an outer periphery of the upper clamping member and an inner periphery of the lower clamping member.

Embodiment 12
In the embodiments described in Embodiments 3 to 4,
One of the upper and lower holding members has a curled portion, and one end of the other holding member faces the curled portion to hold the metal diaphragm.

Embodiment 13
In the embodiments described in Embodiments 3 to 4,
A high-pressure fuel supply pump characterized in that diameters of contact portions of the upper holding member and the metal diaphragm damper, and contact portions of the lower holding member and the metal diaphragm are equal.

Embodiment 14
In the embodiments described in Embodiments 3 to 4,
The cover is formed in a cup shape, and the open side annular end surface is in contact with the annular surface of the damper accommodating chamber peripheral edge of the body, and both are joined by welding around the entire outer periphery of the abutting surface portion A fuel pulsation reduction device in a high pressure fuel supply device for an internal combustion engine, characterized by:

Embodiment 15
A fuel pulsation reducing device in a high pressure fuel supply device for an internal combustion engine, comprising: a damper storage chamber provided with a fuel inlet and an outlet, the damper storage chamber forming a part of the fuel passage, and the body The damper is made up of two metal diaphragms whose outer peripheral edges are joined, and the gas is sealed in the space between the two diaphragms. The damper is held by a pair of upper and lower holders and mounted between the body and the cover, and both of the two metal diaphragms are exposed to the flow of fuel in the damper storage chamber,
The high-pressure fuel supply system for an internal combustion engine according to claim 1, wherein the pair of holders are interlocked with each other in a state of holding the diaphragm so that the three holders and the diaphragm form an assembly. Fuel pulsation reduction device in the device.

Embodiment 16
Among those described in Embodiment 15,
A high pressure fuel supply system for an internal combustion engine, wherein the damper storage chamber is connected to a fuel pipe connected to a high pressure fuel supply pump of a high pressure fuel supply system for an internal combustion engine independently from the high pressure fuel supply pump. Fuel pulsation reduction device in Japan.

Embodiment 17
Among those described in Embodiment 15,
The high pressure fuel supply of an internal combustion engine, wherein the body of the damper storage chamber is formed by a pump body of a high pressure fuel supply pump in a high pressure fuel supply device of an internal combustion engine, and the cover is fixed to the pump body. Fuel pulsation reduction device in the device.

Embodiment 18
In any one of the embodiments 15 to 17,
A fuel pulsation reduction device in a high pressure fuel supply device for an internal combustion engine, wherein the pair of holders are mutually engaged by press fitting.

Embodiment 19
In the embodiments as described in embodiment 17,
A fixing force for fixing the cover to the body is a contact portion between the cover and one of the pair of holders, and the other of the pair of holders via the press-fit portion of the both holders. A fuel pulsation reducing device in a high pressure fuel supply device for an internal combustion engine, characterized in that it acts on the body in contact with a holder.

Embodiment 20
Among those recited in claim 19,
The cover is formed in a cup shape, and the open side annular end face is in contact with the annular surface of the periphery of the damper storage chamber of the body, and both are joined by welding around the entire outer periphery of the contact face portion A fuel pulsation reduction device in a high pressure fuel supply device for an internal combustion engine, characterized by:

The problems to be solved by the above embodiment are as follows.
1) In the prior art, if the fuel is spread over both sides of the metal diaphragm damper, the cover is made of a thick member when the annular flat portion of the metal diaphragm damper is pressed and fixed over the entire circumference. As a result, the pressure pulsation reducing mechanism is heavy.
2) If fuel can not be distributed to both sides of the metal diaphragm damper, pressure pulsations generated in the fuel can not be sufficiently absorbed.
3) If a structure is not adopted in which the annular flat plate portion of the metal diaphragm damper is pressed and fixed over the entire circumference, stress exceeding the allowable value is generated in the welded portion and the welded portion is broken.

  One of the purposes of the embodiment is 1) taking a structure in which the annular flat portion of the metal diaphragm damper is held and fixed over the entire circumference while spreading the fuel over both sides of the metal diaphragm damper, and pressure pulsation reduction It reduces the weight of the mechanism.

  In order to achieve this object, in the present embodiment, in order to basically solve the above-mentioned problems, according to the present invention, the peripheral portion of the metal diaphragm damper is vertically held by a pair of upper and lower holding members. A third party is unitized as a damper unit in that state, covers the damper unit and contacts the upper clamping member of the damper unit to press the damper unit against the body of the high-pressure fuel supply pump, A passage communicating the inside and the outside is provided between the cover and the upper holding member, and the space between the metal diaphragm damper and the cover is communicated between the metal diaphragm damper and the body.

  The upper and lower holding members are in contact with the peripheral portion of the metal diaphragm damper over the entire circumference.

  The cover is formed in a cup shape, and the open side annular end face is in contact with the annular surface of the periphery of the damper storage chamber of the body, and both are joined by welding on the entire outer periphery of the contact surface.

  In this way, while spreading the fuel over both sides of the metal diaphragm damper, the annular flat portion of the metal diaphragm damper is pressed and fixed over the entire circumference, and the weight of the pressure pulsation reducing mechanism is reduced. It is to make it lighter.

  Further, the holding members are fixed to each other by press-fitting at the peripheral portion outside the metal diaphragm damper to form the damper unit.

  As a result, when assembling the metal diaphragm damper into the high pressure fuel supply pump, the number of parts to be assembled and fixed to the body can be reduced at the same time, and parts shortage and misassembly can be prevented.

  The present invention can be applied to various fuel transport systems as a pressure pulsation reducing mechanism for reducing fuel pulsation. In particular, it is preferable to use as a fuel pulsation reducing mechanism attached to a low pressure fuel passage of a high pressure fuel supply system which pressurizes gasoline and discharges it to an injector. Furthermore, it can be integrally attached to the high pressure fuel supply pump as in the embodiment.

Reference Signs List 1 pump housing 2 plunger 9 metal diaphragm damper (pressure pulsation reducing mechanism, metal damper) 10c damper chamber 11 pressurizing chamber 14 damper cover 30 electromagnetic suction valve mechanism 104, 105 upper and lower holding members (upper and lower pressing members)

Claims (10)

A damper chamber is formed by a pump body and a partition member attached to the pump body, and a low pressure fuel passage is formed to introduce fuel into the pressurizing chamber formed in the pump body through the damper chamber.
The pressure pulsation reducing mechanism housed in the damper chamber includes a metal damper in which a sealed space is formed inside the joint portion by joining two disk-shaped metal diaphragms all around, and the sealed space of the metal damper A pair of pressure members which sandwich the gas around the metal damper at a position on the inner diameter side with respect to the joint, and the outer peripheral surface of either of the pair of pressure members and the other The circumferential surface is a high pressure fuel supply pump unitized by mutually fitting in the state which clamped the said metal damper. In the one described in claim 1,
Both surfaces of the pair of metal diaphragms are exposed to the flow of fuel flowing in the damper chamber and flowing into the pressurizing chamber from the fuel introduction joint portion attached to the pump body when attached to the damper chamber. High pressure fuel supply pump configured to be   The device according to claim 1 or 2, wherein the pair of pressing members respectively have continuous annular surface portions that abut on both outer surfaces of the metal damper, and the metal is interposed between the annular surface portions. A pair of dampers sandwiching the damper, and the pair of pressing members further have a curved portion continuing to the annular surface portion, and further, cylindrical portions parallel to each other are formed following the curved portion, and the facing inner circumferences of the cylindrical portions A high pressure fuel supply pump in which the surface and the outer peripheral surface are joined to form a unit. In the one described in claim 3,
The high pressure fuel supply pump includes a communication passage portion communicating the inside and the outside of the cylindrical portion between the pair of pressing members and an inner wall surface portion of the damper chamber facing the cylindrical portion or the cylindrical portion itself. In the one described in claim 3,
Between the inner circumferential surface of the curved surface portion of the outer pressing member positioned outside of the pair of pressing members and the outer circumferential surface of the curved surface portion of the inner pressing member positioned inside of the pair of pressing members The high pressure fuel supply pump in which the annular space which encloses the said junction part is formed. In the fifth aspect,
A cover member forming the damper chamber in cooperation with the pump body in which the low pressure fuel passage is formed;
The inner wall surface of the cover member is in pressure contact with the outer peripheral surface of the outer pressing member of the pressure pulsation reducing mechanism, and the end surface of either the outer pressing member or the inner pressing member is opposite to the cover member. The high pressure fuel supply pump wherein the metal damper unit is attached to the damper chamber so as to be pressed against the inner wall surface of the damper chamber of the pump body. In the one described in claim 6,
The inner wall surface of the cover member and the outer peripheral surface of the outer pressing member are in pressure contact with each other, and inside and outside the outer pressing member are communicated with each other at portions where the both are not in pressure contact and fuel is circulated. A high pressure fuel supply pump with a gap formed. In one of claims 6 and 7,
A fuel inlet is formed in the cover member, and the metal diaphragm on the side facing the cover member faces the fuel inlet.
A fuel outlet communicating with the pressurizing chamber is formed in a bottom wall surface of the damper chamber, and the metal diaphragm facing the bottom wall surface of the damper chamber faces the fuel outlet. pump. In any of claims 6 to 8,
The high-pressure fuel supply pump in which the pressure pulsation reducing mechanism is pressed against the bottom wall surface of the damper chamber by a part of the fitting force when the cover member is fitted to the outer periphery of the damper chamber formed in the pump body . In one of claims 1 to 9,
The high pressure fuel supply pump, wherein the pair of pressing members are fixed by press-fitting each other and sandwiching the metal diaphragm therebetween.

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