JP2017025924A - Pressure pulsation reduction mechanism for fuel and high pressure fuel supply pump of internal combustion engine including the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: 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 reduction 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.

  Further, the present invention relates to a high-pressure fuel supply pump for an internal combustion engine that is integrally provided with such a pressure pulsation reducing mechanism.

  A conventional fuel pressure pulsation reduction mechanism joins two metal diaphragms and sandwiches a metal damper filled with gas between a damper chamber provided in the pump body and a cover attached to the body. It is comprised in this way, and is accommodated in the damper chamber formed in the low-pressure fuel passage to the pressurization chamber of the high-pressure fuel demand pump.

  Specifically, two metal diaphragms are welded on the outer periphery thereof, and have a disc-shaped bulge portion in which gas is sealed in the center, and two sheets are interposed between the outer weld portion and the disc-shaped bulge portion. An annular flat plate portion on which metal diaphragms overlap is provided. And what sandwiches both outer surfaces of this flat plate part with the thick part provided in the cover and the main body, or sandwiched between the cover and the annular flat plate part and between the main body and the annular flat plate part with an elastic body It has been known.

There are also known high-pressure fuel supply pumps equipped with such a fuel pressure pulsation reduction mechanism (Japanese Patent Laid-Open No. 2004-138071, Japanese Translation of PCT International Publication No. 2006-521487, Japanese Patent Laid-Open No. 2003-254191, and Japanese Patent Laid-Open No. 2003-254191). 2005-42554 gazette).

JP 2004-138071 A JP-T-2006-521487 JP 2003-254191 A JP 2005-42554 A

  In the above prior art, when a metal damper composed of a metal diaphragm as a pressure pulsation reducing mechanism is assembled into a low pressure fuel passage or a high pressure fuel supply pump, it is necessary to simultaneously incorporate and fix many parts in the body. There was a problem that it was easy to cause parts shortage and misassembly.

  An object of the present invention is to reduce the number of parts during the work of assembling a metal diaphragm damper as a pressure pulsation reducing mechanism into a low-pressure fuel passage, and to prevent parts from being missing or misassembled.

  Another object of the present invention is to reduce the number of parts when the pressure pulsation reduction mechanism is assembled to the high pressure fuel supply pump in a high pressure fuel supply pump having a pressure pulsation reduction mechanism, thereby preventing parts 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 is formed through the damper chamber to introduce a fuel into a pressurized chamber formed in the pump body. The stored pressure pulsation reducing mechanism has a metal damper in which two disk-shaped metal diaphragms are joined over the entire circumference and a sealed space is formed inside the joint, and gas is sealed in the sealed space of the metal damper. A pair of pressing members that sandwich the periphery of the metal damper at a position on the inner diameter side of the joint, and the outer peripheral surface of one of the pair of pressing members and the other inner peripheral surface sandwich the metal damper. The high-pressure fuel supply pumps are unitized by being fitted to each other in the above state.

  When the metal diaphragm damper as the pressure pulsation reducing mechanism is assembled into the low pressure fuel passage or the high pressure fuel supply pump, the number of parts to be incorporated into the body or fixed at the same time can be reduced, and parts shortage and misassembly can be prevented.

1 is an example of a fuel supply system using a high-pressure fuel supply pump according to a first embodiment in which the present invention is implemented. 1 is a longitudinal sectional view of a high-pressure fuel supply pump according to a first embodiment in which the present invention is implemented. It is a longitudinal cross-sectional view of the high pressure fuel supply pump by 1st Example with which this invention was implemented, and represents the longitudinal cross-sectional view of the position rotated 90 degrees of FIG. 1 is an example of a fuel supply system using a high-pressure fuel supply pump according to a first embodiment in which the present invention is implemented, and particularly shows a detailed fuel flow in the high-pressure fuel supply pump. It is the figure which showed the generation | occurrence | production mechanism of the suction pressure pulsation which generate | occur | produces with the high pressure fuel supply pump by 1st Example by which this invention was implemented. It is the figure which showed the relationship between the suction pressure pulsation which generate | occur | produces with the high pressure fuel supply pump by 1st Example by which this invention was implemented, and the area of the small diameter part 2a of the plunger. (A), (b) is a longitudinal cross-sectional view of the high-pressure fuel supply pump by 1st Example by which this invention was implemented, Comprising: The enlarged view (a) of the part relevant to the metal diaphragm damper 9, and a perspective view (B). (A), (b) is a longitudinal cross-sectional view of the high-pressure fuel supply pump according to the first embodiment in which the present invention is implemented, showing a cross-section perpendicular to FIG. 7, and particularly a portion related to the metal diaphragm damper 9 FIG. 2 is an enlarged view (a) and a perspective view (b). It is a figure which shows the damper unit 118 at the time of assembling the high pressure fuel supply pump by 1st Example by which this invention was implemented, and the method of assembling it to the pump housing 1 and the damper cover. It is an example of the system diagram of the high-pressure fuel supply pump by the 2nd example with which the present invention was implemented, and shows the flow of the fuel especially in a high-pressure fuel supply pump in detail. 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 the 3rd Example by which this invention was implemented, and is an enlarged view of the 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 the 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.

  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 a direction perpendicular to FIG.

  In FIG. 1, a portion surrounded by a broken line indicates a pump housing 1 of the high-pressure pump, and mechanisms and components shown in the broken line indicate that they are integrated into the pump housing 1 of the high-pressure pump. .

  The fuel in the fuel tank 20 is pumped up by the 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 the suction pipe 28 to the suction port 10a of the high-pressure fuel supply pump. Sent to.

  The fuel that has passed through the suction port 10a passes through a filter 102 fixed in the suction joint 101, and further passes through a metal diaphragm damper 9 and suction passages 10b and 10c. It reaches the suction port 30a.

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

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

  The electromagnetic intake valve mechanism 30 includes an electromagnetic coil 30b. When the electromagnetic coil 30b is energized, the electromagnetic plunger 30c is moved rightward in FIG. 1, and the compressed state of the spring 33 is maintained.

  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 differential pressure between the suction flow path 10 c (suction port 30 a) and the pressurizing chamber 11, the suction valve element 31 is urged by the biasing force of the spring 33. Is energized in the valve closing direction, and the suction port 32 is closed.

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

  By the valve opening force due to this fluid differential pressure, the suction valve body 31 is set to open over the biasing force of the spring 33 and open the suction port 32.

In this state, when a control signal from the ECU 27 is applied to the electromagnetic intake valve mechanism 30, an electric current flows through the electromagnetic coil 30b of the electromagnetic intake valve mechanism 30, and the electromagnetic plunger 30c is generated as shown in FIG. The spring 33 is kept in a compressed state.
As a result, the state in which the suction valve body 31 opens the suction port 32 is maintained.

  When the plunger 2 finishes the suction process while the application state of the input voltage is maintained in the electromagnetic suction valve mechanism 30 and the plunger 2 moves to the compression process in which the plunger 2 is displaced upward in FIG. 2, the magnetic urging force remains maintained. The intake valve body 31 is still open.

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

  In this state, when the control signal from the ECU 27 is canceled and the energization to the electromagnetic coil 30b is cut off, the magnetic biasing force acting on the electromagnetic plunger 30c is after a certain time (after magnetic and mechanical delay time). Erased. Since the biasing force by the spring 33 is acting on the suction valve body 31, the suction valve body 31 closes the suction port 32 by the biasing force by the spring 33 when the electromagnetic force acting on the electromagnetic plunger 30 c disappears. When the suction port 32 is closed, the fuel pressure in the pressurizing chamber 11 increases with the upward movement of the plunger 2 from this time. When the pressure in the fuel discharge port 12 or higher is reached, high pressure discharge of the fuel remaining in the pressurizing chamber 11 is performed via the discharge valve unit 8 and supplied to the common rail 23. This process is called a discharge process. That is, the compression process of the plunger 2 (the ascending process from the lower start point to the upper start point) includes a return process and a discharge process.

  And the quantity of the high-pressure fuel discharged can be controlled by controlling the timing which cancels | releases electricity supply to the electromagnetic coil 30c of the electromagnetic suction valve mechanism 30. FIG.

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

  That is, the amount of fuel returned to the suction channel 10c (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 ratio of the return process in the compression process is large and the ratio of the discharge process 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 for releasing the energization of the electromagnetic coil 30c is controlled by a command from the ECU.

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

  Thus, the fuel guided to the fuel inlet 10a is introduced into the pressurizing chamber 11 of the pump housing 1 and a required amount is pressurized to a high pressure by the reciprocating motion of the plunger 2, and is pumped from the fuel outlet 12 to the common rail 23. .

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

  A convex portion 1A as a pressurizing chamber 11 is formed at 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 pressurizing chamber 11 and the discharge port 12. ing. Further, a hole 30A for mounting an electromagnetic suction valve mechanism 30 for supplying fuel to the pressurizing chamber 11 is provided on the outer wall of the pump housing on the same axis as the recess 11A for mounting the discharge valve mechanism 8. .

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

  A cylinder 6 that guides the reciprocating motion of the plunger 2 is attached so as to face the pressurizing chamber.

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

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

  In a state where there is no fuel differential pressure between the pressurizing chamber 11 and the discharge port 12, the discharge valve 8b is pressed against the seat member 8a by the urging force of the discharge valve spring 8c and is in a closed state. Only when the fuel pressure in the pressurizing chamber 11 becomes larger than the fuel pressure in the discharge port 12 by a predetermined value, the discharge valve 8b is opened against the discharge valve spring 8c, and the pressure in the pressurizing chamber 11 is increased. The fuel is discharged to the common rail 23 through the discharge port 12.

  When the discharge valve 8b is opened, the discharge valve 8b comes into contact with the holding member 8d and its 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 into the pressurizing chamber 11 again due to the delay in closing the discharge valve 8b, and the efficiency of the high-pressure pump will decrease. . Further, when the discharge valve 8b repeats opening and closing movements, the holding member 8d guides the discharge valve 8b to move only in the stroke direction. By configuring as described above, the discharge valve mechanism 8 becomes a check valve that restricts the flow direction of fuel.

  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 fixed to the engine by a set screw 42 via a flange 41. A bush 43 exists between the flange 41 and the engine. Since the flange holder 40 is fixed to the pump housing 1 by a screw threaded on the inner periphery, the pump housing is thereby fixed to the engine.

  Although the bush 43 is fixed to the flange 41, this allows the flange 41 to have a flat shape without a bent portion as shown in FIG. Thereby, formation of the flange 41 becomes easy.

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

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

  Hereinafter, the operation of the relief valve mechanism 200 will be described. The relief valve 202 is pressed against the relief valve seat 201 by a relief spring 204 that generates a pressing force. When the pressure difference between the suction chamber and the relief passage exceeds a specified pressure, the relief valve 202 is pressed against the relief valve seat. The set valve opening pressure is set so as to open the valve away from 201. Here, the pressure when 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, a relief valve 202, a relief press 203, a relief spring 204, and a relief spring adjuster 205 that are integral with the relief valve seat 201. The relief valve mechanism 200 is assembled as a subassembly outside the pump housing 1 and then 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 this order, and the relief spring adjuster 205 is press-fitted and fixed to the relief valve housing 206. The set load 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 formed is press-fitted and fixed to the pump housing 1.

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

  When the abnormal 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, the high-pressure fuel supply pump, or the like exceeds the set valve opening pressure of the relief valve The fuel reaches the relief valve 202 through the relief flow path 211 from the downstream side of the discharge valve 8b. Then, the fuel that has passed through the relief valve 202 is released to the suction flow path 10c that is the low pressure portion of the escape passage 208 opened in the relief spring adjuster 205. As a result, the high-voltage portion such as the common rail 23 is protected.

  The outer periphery of the cylinder 6 is held by a cylinder holder 7, and the cylinder holder 7 is held inside the flange holder 40. By screwing a screw 410 threaded on the inner periphery of the flange holder 40 into a screw 411 threaded on the pump housing 1, the cylinder 6 is fixed to the pump housing 1 via the cylinder holder 7. The cylinder 6 holds the plunger 2 that moves forward and backward in the pressurizing chamber 11 so as to be slidable along the forward and backward movement direction.

  The lower end of the plunger 2 is provided with a tappet 3 that converts the rotational motion of the cam 5 attached to the camshaft of the engine into a vertical motion and transmits it to the plunger 2. The plunger 2 is pressure-bonded to the tappet 3 by a spring 4 through a retainer 15. The retainer 15 is fixed to the plunger 2 by press-fitting. Thereby, the plunger 2 can be moved back and forth (reciprocated) up and down with the rotational movement of the cam 5.

  Further, the plunger seal 13 held at the lower end of the inner periphery of the cylinder holder 7 is installed in a state in which the plunger seal 13 is slidably in contact with the outer periphery of the plunger 2 at the lower end of the cylinder 6 in the figure. Is prevented from flowing into the tappet 3 side, that is, inside 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 pump housing 1.

  Here, the suction channel 10c is connected to the seal chamber 10f via the suction channel 10d and the suction channel 10e provided in the cylinder 6, and the seal chamber 10f is always connected to the pressure of the intake fuel. Yes. When the fuel in the pressurizing chamber 11 is pressurized to a high pressure, a minute amount of high-pressure fuel flows into the seal chamber 10f through the sliding clearance between the cylinder 6 and the plunger 2, but the inflowed high-pressure fuel is released to the suction pressure. Therefore, the plunger seal 13 is not damaged by the high pressure.

  The plunger 2 includes a large-diameter portion 2 a that slides with the cylinder 6 and a small-diameter portion 2 b that slides with the plunger seal 13. The diameter of the large diameter portion 2a is set larger than the diameter of the small diameter portion 2b, and is set coaxially with each other. In 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 so, it is possible to reduce the pressure pulsation on the low pressure side generated on the low pressure side upstream of the electromagnetic suction valve mechanism 30 as the plunger moves up and down.

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

  FIG. 4 is a system diagram of the high-pressure fuel supply pump in this 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 between 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 this 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 part of the fuel flows from the suction flow path 10c into the pressurizing chamber 11 through the suction valve body 31 (1). The remaining portion flows from the suction flow channel 10c into the seal chamber 10f through the suction flow channel 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 in the direction of the arrow in FIG. If the value is negative, it means that the fuel flows in the direction opposite to the arrow.

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

  The top table shows the movement of the plunger, TDC (abbreviation for TOP DEAD CENTER) is when the position of the plunger 2 is at the top in FIG. 2, and BDC (abbreviation for BOTTOM DEAD CENTER) is for the plunger 2 It shows when the position is at the bottom. As described above, the plunger 2 includes the suction process during the downward movement, and includes the return process and the discharge process during the upward movement.

  Further, the lower figure shows fuel flows (1), (2) and (3).

In the drawing, “S” is the ratio of “cross-sectional area of the small diameter portion 2 b” to “cross-sectional area of the large diameter portion 2 a” in the plunger 2. In 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
= 0.36.

Next, the state of the fuel flows (1), (2), and (3) during each step will be described.
Suction Step (1) The volume of the pressurizing chamber 11 is increased by the downward movement of the plunger 2, and the fuel corresponding to the increased volume flows from the suction flow path 10c. The increase in volume in this case is generated by the large diameter portion 2a, and the increase at this time is 1. Therefore, the fuel flow rate 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 the volume reduction flows backward from the seal chamber 10f. Then, it flows out to the suction channel 10c. The volume decrease in this case is
1-S, and the flow of fuel also considers the direction
-(1-S).

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

Returning Step (1) The volume of the pressurizing chamber 11 is reduced by the upward movement of the plunger 2, and the fuel corresponding to the volume reduction flows out to the suction passage 10c. As in the inhalation step, the volume reduction amount in this case is generated by the large-diameter portion 2a. Therefore, in the table, the amount of fuel flow is -1.

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

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

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

(2) The fuel flow is the same as the above return process.
1-S.

(3) The fuel (3) flowing from the suction port 10a into the suction flow path 10c is
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 is related to this “fuel (3) flowing from the suction port 10a into the suction flow path 10c”. In the table at the bottom of FIG. 8, T indicates the ratio of the discharge process occupying the plunger 2 ascending process. Then, the ratio of the inhalation process in the ascending process of the plunger 2 is
1-T.

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

          When T = 1, there is no return process, and all the fuel flowing into the pressurizing 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 quantities.
(A) Total amount of fuel flowing from the suction port 10a to the suction flow channel 10c (b) Total amount of fuel flowing from the suction port 10c to the suction flow channel 10a Here, (a) is a table at the bottom of FIG. It corresponds to the area of the shaded area,
(A) = [S * 1] + (1-S) T
On the other hand, (b) corresponds to the area of the shaded portion,
(B) = S (1-T)
Therefore, calculate (c) = (a) + (b)
(C) = (a) + (b) = (1-2S) T + 2S.

FIG. 6 shows the relationship between T and the above (c).
When S = 1, the diameter and the cross-sectional area of the small diameter portion 2a and the large diameter portion 2b 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 the largest. This means that all the fuel once sucked into the pressurizing chamber 11 is returned to the suction port 10a.

  On the other hand, as T increases, the suction pressure pulsation decreases. This indicates that since the fuel in the pressurizing chamber 11 is discharged at a high pressure to the common rail 23 in the discharge process, the amount of fuel returning 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 cannot actually occur.

  At T = 0, no suction pressure pulsation occurs. This indicates that the fuel only goes back and forth between the pressurizing chamber 11 and the seal chamber 10f, and there is no fuel going back and forth between the suction port 10a and the suction flow path 10c.

  The pressure pulsation increases as T increases. This is because in the discharge step, 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 seal chamber 10f so that the fuel flows into the suction passage 10c from the suction port 10a.

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

From the above, it is desirable that S is as small as possible.
However, reducing S means that the small-diameter portion 2b of the plunger 2 is thinned. If it is too thin, the strength of the small-diameter portion 2a is insufficient and the plunger 2 is damaged.

  In this 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 characteristics at S = 0.36 are shown in FIG.

  Thereby, it is understood that the low pressure pulsation can be reduced as compared with the case of S = 1 while ensuring the strength of the small diameter portion 2b.

  Next, the metal diaphragm damper 9 for absorbing the pressure pulsation for reducing the low pressure pressure pulsation generated by the above mechanism and a method for fixing the metal diaphragm damper 9 will be described.

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

  FIG. 8 is an enlarged view and a perspective view of the metal diaphragm damper 9 portion for absorbing pressure pulsation in FIG. 3.

  FIG. 9 shows an assembling procedure when the damper unit 118 is fixed to the pump housing 1.

  The damper unit 118 is composed of two metal diaphragms 9a and 9b. The outer periphery of the damper unit 118 is fixed to each other by welding all around the welded portion 9d in a state where the gas 9c is sealed in the space between the two diaphragms. A flat portion exists inside the welded portion 9d, and this portion is sandwiched so as to be installed in the low-pressure passage of the high-pressure fuel supply pump to form and fix the suction passages 10b and 10c.

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

  The metal diaphragm damper 9 is sandwiched from above and below by the upper clamping member 104 and the lower clamping member 105, and when assembled, as shown in FIG. 9, first, the damper unit 118 is formed as a unit in this state.

  The upper clamping member 104 has a curled portion 119, and the upper end of the lower clamping member 105 faces the curled portion 119 to sandwich the flat plate portion of the metal diaphragm damper 9. The diameters of the contact portion between the upper clamping member 104 and the metal diaphragm damper 9 and the contact portion between the lower clamping member 105 and the metal diaphragm damper 9 are the same, 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 the peripheral portion outside the metal diaphragm damper 9. The welded portion 9d of the metal diaphragm damper 9 is arranged in a space 107 formed between the lower clamping members 105.

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

  Moreover, since it is clamped and fixed symmetrically over the entire circumference, no stress is generated by fixing other than the fixed portion.

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

  The damper unit 118 configured as described above is housed in a recess formed in the pump housing 1. At that time, positioning in the radial direction is performed between the outer peripheral portion 116 of the upper clamping member 104 and the inner peripheral portion 117 of the pump housing 1, but 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 an annular end surface on the open side thereof is welded and fixed to the pump housing 1 and a weld 106.

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

  The recessed end surface 115 of the pump housing 1 is in contact with the lower clamping member 105, and has a partially missing annular structure due to a partially missing body missing portion 113. The damper unit 118 is not in contact. The body lacking portion 113 also lacks the inner peripheral portion 117, and this missing portion 113 does not contribute to positioning with the outer peripheral portion 116 of the upper clamping member 104.

  The damper unit 118 is fixed in such a manner that the upper clamping member 104 is clamped by the damper cover 14 from the upper side and the lower clamping member 105 is clamped from the lower side. This is fixed in a direction that promotes press-fitting of the upper clamping member 104 and the lower clamping member 105.

  Thus, the press-fitting of the upper clamping member 104 and the lower clamping member 105 is not loosened due to fuel pressure pulsation, engine vibration, or the like, and the metal diaphragm damper 9 is not loosely fixed.

  The suction passage 10 b between the damper cover 14 and the metal diaphragm damper 9 communicates with the annular space 121 between the damper cover 14 and the upper clamping 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 communicated with the annular space 121 between the damper cover 14 and the upper clamping member 104 by the body missing portion 113.

  Thereby, 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 channel 10b and the suction channel 10c are communicated. The fuel that has flowed into the high-pressure fuel supply pump from the suction port 10 a flows through the suction flow path 10 b and then 10 c, so that all the fuel flow (3) in FIG. 4 passes through the metal diaphragm damper 9. As a result, the fuel spreads on both surfaces 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 press-molding a rolled steel plate, and therefore the thickness of the cover is uniform everywhere. When fixing to the pump housing 1, first, the damper cover 14 is temporarily press-fitted into the pump housing 1 by the press-fit portion 122 and fixed. At this point, the protrusion 120 of the damper cover 14 and the upper clamping member 104 are already in contact with each other at the contact portion 114, and the recessed end surface 115 of the pump housing 1 and the lower clamping member 105 are in contact with each other. Is rigidly fixed to the pump housing 1 and the damper cover 14.

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

  The damper cover 14 is displaced in a direction in which the damper unit 118 is pressed by the pump housing 1 and the damper cover 14 due to thermal strain generated after welding, so that the clamping force of the damper unit 118 is not attenuated even after welding.

  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-fitting load is set to a tightening margin so that the high pressure fuel in the relief flow path 211 does not cause the relief valve housing 206 to escape upward in the drawing.

  However, even if the relief valve housing 206 is pulled out upward in the drawing by high pressure fuel due to some mistake, the relief valve housing 206 and the lower clamping member 105 first come into contact with each other to prevent the removal.

  Specifically, the relief flow path 211 that is a hole for press-fitting the relief valve housing 206 is positioned so as to overlap the recessed end surface 115 of the pump housing 1, and the relief unit 118 is inserted into the pump housing 1 before the relief unit 118 is inserted into the pump housing 1. The valve mechanism 200 is press-fitted and fixed in the relief flow path 211. At that time, the relief valve housing 206 is press-fitted and fixed so that the upper end surface of the relief valve housing 206 is below the recessed end surface 115 of the pump housing 1.

  With such a configuration, even if the relief valve housing 206 is pulled out by the high-pressure fuel, the relief valve housing 206 and the lower clamping member 105 come into contact first.

  In this embodiment, the suction joint 101 is fixed to the damper cover missing portion 112 of the damper cover 14 by the welded portion 103. The filter 102 is fixed to the suction joint 10a. The suction port 10a 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 those in the first embodiment, and all the symbols and numbers described are the same as those in the first embodiment.

  FIG. 10 shows a system diagram of the high-pressure fuel supply pump in this 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 is fixed by a welding portion 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 the fuel flowing into the high-pressure fuel supply pump passes through this filter 102.

The suction port 10a is connected to the suction channel 10d, and the low-pressure fuel that has entered the high-pressure fuel supply pump from the suction port 10a passes through the filter 102 and is first guided to the suction channel 10d (3).
From there, the fuel (1) is directed to the pressurizing chamber 11 through the suction channels 10b2 and 10c, and the fuel (2) is directed to the seal chamber 10f. Therefore, also in this case, the following relationship is established.

          (3) = (1) + (2)

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

  The suction flow channel 10b2 and the suction flow channel 10c communicate with each other via the annular space 121 as in the first embodiment. As a result, the fuel is sufficiently distributed to both surfaces 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 such a case, the size and weight of the high-pressure fuel supply pump do not increase, and the size and weight can be maintained.

  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 those in the first embodiment, and all the symbols and numbers described are the same as those in the first embodiment.

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

  In the present embodiment, as in the first embodiment, the lower holding member 105 protrudes downward in the drawing from the upper holding member 104. And let the protrusion amount be 123.

  Similarly to the first embodiment, the upper clamping member 104 is in contact with the damper cover 14 and the lower clamping member 105 is in contact with the pump housing 1.

In this embodiment, the protruding amount 123 is set to a small value of 0.5 mm or less.
By doing so, the press-fitting portions of the upper clamping member 104 and the lower clamping member 105 can be set sufficiently long. Therefore, when the damper unit 118 is fixed between the damper cover 14 and the pump housing 1, the fixing is performed. Even if a variation (individual difference) occurs in the force, it can be absorbed, and the variation in the force with which the upper clamping member 104 and the lower clamping member 105 clamp the metal diaphragm damper 9 can be reduced.

  The damper cover 14 is displaced in a direction in which the damper unit 118 is pressed by the pump housing 1 and the damper cover 14 due to thermal strain generated after the damper cover 14 is welded to the pump housing 1, but this displacement also varies (individual differences). .

  By adopting the structure as in the present 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 recessed end surface 115 of the pump housing 1 and the lower end portion 124 of the upper clamping member 104 are in contact, and the pump housing 1 and the lower clamping member 105 are not in contact. . The other parts are the same as those in the first embodiment, and all the symbols and numbers described are the same as those in the first embodiment.

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

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

  According to this structure, the metal diaphragm damper 9 is clamped up and down only by mutual pressure input between the upper clamping member 104 and the lower clamping member 105.

  Therefore, even if the force for pressing 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 for holding the metal diaphragm damper 9, and the metal Breakage of the diaphragm damper 9 can be prevented.

  If the metal diaphragm damper 9 is damaged, the pressure pulsation of the fuel in the suction pipe 28 exceeds an allowable value, leading to damage to the suction pipe 28, fuel leakage, and the like.

  Further, when the relief valve housing 206 is pulled out upward in the drawing by high pressure fuel due to some mistake, the relief valve housing 206 and the upper clamping member 104 first contact each other, and the mechanism prevents the removal there.

  Even in this case, the force for clamping the metal diaphragm damper 9 is not changed.

  The above embodiment can be summarized as follows.

[Embodiment 1]
A suction passage for sucking fuel into the pressurization chamber; a discharge passage for discharging the fuel from the pressurization chamber; and a fuel reciprocating in the pressurization chamber for sucking and discharging fuel; A suction valve is provided in the suction flow path and a discharge valve is provided in the discharge flow path, and the pressure pulsation is reduced by changing the volume due to the pressure pulsation of the fuel in the suction flow path or in the low pressure chamber communicating with the suction flow path. In the high pressure fuel supply pump, which is a metal diaphragm damper in which two metal diaphragms are welded at the peripheral edge thereof and a gas is sealed between them, the pressure pulsation reduction damper is provided.
The metal diaphragm damper exists in a space formed by a body and a cover, and the cover has a protruding portion protruding inward, and the metal diaphragm damper is sandwiched and fixed by the protruding portion and the body. High pressure fuel supply pump characterized by

[Embodiment 2]
In what is described in embodiment 1,
The high-pressure fuel supply pump according to claim 1, wherein the protrusion has an annular protrusion that is partially missing.

[Embodiment 3]
In what is described in embodiment 1 or 2,
By sandwiching the periphery of the metal diaphragm damper up and down with a pair of upper and lower clamping members, the three members are unitized as a damper unit in that state, and the protruding portion of the cover and the upper side of the damper unit The metal diaphragm damper is sandwiched and fixed by sandwiching the damper unit between the cover and the body in contact with the sandwiching member, and a passage communicating inside and outside between the cover and the upper sandwiching member is provided. A high-pressure fuel supply pump is provided, wherein a space between the metal diaphragm damper and the cover is communicated between the metal diaphragm damper and the body.

[Embodiment 4]
A suction passage for sucking fuel into the pressurization chamber; a discharge passage for discharging the fuel from the pressurization chamber; and a fuel reciprocating in the pressurization chamber for sucking and discharging fuel; A suction valve is provided in the suction flow path and a discharge valve is provided in the discharge flow path, and the pressure pulsation is reduced by changing the volume due to the pressure pulsation of the fuel in the suction flow path or in the low pressure chamber communicating with the suction flow path. In the high pressure fuel supply pump, which is a metal diaphragm damper in which two metal diaphragms are welded at the peripheral edge thereof and a gas is sealed between them, the pressure pulsation reduction damper is provided.
With the pair of upper and lower clamping members, the peripheral portion of the metal diaphragm damper is clamped up and down, so that the three members are unitized as a damper unit in that state, covering the damper unit and holding the upper side of the damper unit The damper unit is pressed against the body of the high-pressure fuel supply pump in contact with a member, and a passage communicating between the inside and the outside is provided between the cover and the upper clamping member, and between the metal diaphragm damper 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 what is described in embodiments 3 to 4,
The high-pressure fuel supply pump, wherein the upper and lower clamping members are in contact with the peripheral edge of the metal diaphragm damper over the entire circumference.

[Embodiment 6]
In what is described in embodiments 3 to 4,
The high-pressure fuel supply pump is characterized in that the upper and lower clamping 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 what is described in embodiments 3 to 4,
An annular space is formed between the upper and lower clamping members, and a welded portion of the metal diaphragm damper is housed in the space.

[Embodiment 8]
In what is described in embodiments 3 to 4,
A high-pressure fuel supply pump, wherein an outer periphery of one of the upper and lower clamping members forms a radial positioning surface with the body.

[Embodiment 9]
In what is described in embodiments 3 to 4,
The high-pressure fuel supply pump is characterized in that the upper and lower clamping members are fixed to each other by welding at a peripheral portion to form the damper unit.

[Embodiment 10]
In what is described in embodiments 3 to 4,
The high-pressure fuel supply pump, wherein the upper clamping member is in contact with the cover, and the lower clamping member is in contact with the body.

[Embodiment 11]
In what is described in embodiments 3 to 4,
A relief passage that connects a high-pressure portion downstream from the discharge valve and a space formed by the body and the cover, and the flow of fuel in the relief passage is high-pressure downstream from the discharge valve. In the high-pressure fuel supply pump provided with a restriction valve that restricts in one direction from the portion into the space formed by the body and the cover,
The high-pressure fuel supply pump, wherein the relief flow path overlaps between an outer periphery of the upper clamping member and an inner periphery of the lower clamping member.

[Embodiment 12]
In what is described in embodiments 3 to 4,
One of the upper and lower clamping members has a curled portion, and one end of the other clamping member faces the curled portion to sandwich the metal diaphragm.

[Embodiment 13]
In what is described in embodiments 3 to 4,
The high-pressure fuel supply pump, wherein the diameters of the contact portion between the upper clamping member and the metal diaphragm damper and the contact portion between the lower clamping member and the metal diaphragm are equal.

[Embodiment 14]
In what is described in embodiments 3 to 4,
The cover is formed in a cup shape, and its open-side annular end surface is in contact with the annular surface at the periphery of the damper accommodating chamber of the body, and both are joined by welding on the entire outer periphery of the contact surface portion. A fuel pulsation reducing device in a high-pressure fuel supply device for an internal combustion engine.

[Embodiment 15]
A fuel pulsation reducing device for a high-pressure fuel supply device of an internal combustion engine, comprising a damper accommodating chamber provided with an inlet and an outlet for fuel, the damper accommodating chamber forming a part of the fuel passage, and the body The damper housed in the damper housing chamber is composed of two metal diaphragms joined at the outer peripheral edge, and gas is sealed in the space between both diaphragms, The damper is held between 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 fuel flow in the damper accommodating chamber.
The pair of holders are engaged with each other in a state of holding the diaphragm, and as a result, the pair of holders and the diaphragm form an assembly. Fuel pulsation reducing device in the apparatus.

[Embodiment 16]
Embodiment 15
The high-pressure fuel supply device for an internal combustion engine, wherein the damper housing chamber is connected independently of the high-pressure fuel supply pump to a fuel pipe connected to a high-pressure fuel supply pump of the high-pressure fuel supply device for the internal combustion engine. Fuel pulsation reduction device.

[Embodiment 17]
Embodiment 15
The high-pressure fuel supply for an internal combustion engine, wherein the body of the damper housing chamber is formed by a pump body of a high-pressure fuel supply pump in a high-pressure fuel supply device for an internal combustion engine, and the cover is fixed to the pump body. Fuel pulsation reducing device in the apparatus.

[Embodiment 18]
In any one of embodiments 15 to 17,
A fuel pulsation reducing device in a high-pressure fuel supply device for an internal combustion engine, wherein the pair of holders are locked together by press-fitting.

[Embodiment 19]
Embodiment 17
The 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 through the press-fit portion of the two holders. A fuel pulsation reducing device in a high-pressure fuel supply device for an internal combustion engine, which acts on the body in contact with a holder.

[Embodiment 20]
Claim 19
The cover is formed in a cup shape, its open-side annular end surface is in contact with the annular surface at the periphery of the damper accommodating chamber of the body, and both are joined by welding on the entire outer periphery of the contact surface portion. A fuel pulsation reducing device in a high-pressure fuel supply device for an internal combustion engine.

The problems to be solved by the above embodiment are as follows.
1) With the conventional technology, the cover is composed of a thick member when the structure is such that the fuel is spread over both sides of the metal diaphragm damper and the annular flat plate of the metal diaphragm damper is pressed and fixed all around. Therefore, there is a problem that the weight of the pressure pulsation reducing mechanism is heavy.
2) If the fuel cannot be spread on both sides of the metal diaphragm damper, the pressure pulsation generated in the fuel cannot be sufficiently absorbed.
3) Unless a structure in which the annular flat plate portion of the metal diaphragm damper is pressed and fixed over the entire circumference is taken, stress exceeding the allowable value is generated in the welded portion, and the welded portion is damaged.

  One of the purposes of the embodiment is 1) A structure in which the annular flat plate portion of the metal diaphragm damper is pressed and fixed over the entire circumference while fuel is distributed to both surfaces of the metal diaphragm damper, and pressure pulsation is reduced. It reduces the weight of the mechanism.

  In order to achieve this object, in the present embodiment, in order to basically solve the above-described problem, the present invention is configured by sandwiching 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, covering the damper unit and contacting 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 between the inside and the outside is provided between the cover and the upper clamping member, and a space between the metal diaphragm damper and the cover is communicated between the metal diaphragm damper and the body.

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

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

  In this way, while spreading the fuel on both sides of the metal diaphragm damper, the structure is such that the annular flat plate portion of the metal diaphragm damper is pressed and fixed all around, and the weight of the pressure pulsation reducing mechanism is increased. There is to lighten.

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

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

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

1 Pump housing 2 Plunger 9 Metal diaphragm damper (pressure pulsation reduction mechanism, metal damper)
10c Damper chamber 11 Pressurizing chamber 14 Damper cover 30 Electromagnetic suction valve mechanisms 104, 105 Upper and lower clamping members (upper and lower pressing members)

Claims (10)

In a pump body and a partition member attached to the pump body, a damper chamber is formed, and a low-pressure fuel passage for introducing fuel into the pressurizing chamber formed in the pump body through the damper chamber is formed.
The pressure pulsation reducing mechanism housed in the damper chamber includes a metal damper in which two disk-shaped metal diaphragms are joined over the entire circumference, and a sealed space is formed inside the joint, and the sealed space of the metal damper is provided. Gas is sealed, and has a pair of pressing members that sandwich the periphery of the metal damper at a position on the inner diameter side of the joint, and the outer peripheral surface of one of the pair of pressing members and the other inner side The peripheral surface is a high-pressure fuel supply pump that is unitized by fitting together with the metal damper sandwiched therebetween. What is claimed in claim 1
When both surfaces of the pair of metal diaphragms are attached to the damper chamber, they are exposed to a fuel flow flowing through the damper chamber and flowing into the pressurizing chamber from a fuel introduction joint portion attached to the pump body. High pressure fuel supply pump configured to be   3. The pair of pressing members according to claim 1, wherein each of the pair of pressing members has an uninterrupted annular surface portion that contacts both outer surfaces of the metal damper, and the metal is interposed between the annular surface portions. The damper is further sandwiched, and the pair of pressing members has a curved portion that continues from the annular surface portion, and further, a cylindrical portion that is parallel to each other is formed following the curved portion, and the inner circumference facing the cylindrical portion A high-pressure fuel supply pump in which a surface and an outer peripheral surface are joined to form a unit. What is described in claim 3,
The pair of pressing members is a high-pressure fuel supply pump having a communication passage portion communicating with the inner wall surface portion of the damper chamber facing the cylindrical portion, or communicating with the cylindrical portion itself inside and outside the cylindrical portion. What is described in claim 3,
Between the inner peripheral surface of the curved surface portion of the outer pressing member located on the outer side of the pair of pressing members and the outer peripheral surface of the curved surface portion of the inner pressing member positioned on the inner side of the pair of pressing members. A high-pressure fuel supply pump in which an annular gap containing the joint is formed. What is described in claim 5
A cover member that forms 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 positioned opposite to the cover member. The high-pressure fuel supply pump in which 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. What is described in claim 6,
The inner wall surface of the cover member and the outer peripheral surface of the outer pressing member are partially in pressure contact with each other, and the fuel is circulated through the inside and outside through the outer pressing member to a portion where both are not pressed. A high-pressure fuel supply pump in which a gap is formed. In one of claims 6 or 7,
A fuel introduction port is formed in the cover member, and the metal diaphragm on the side facing the cover member faces the fuel introduction port,
A fuel discharge port leading to the pressurizing chamber is formed on the bottom wall surface of the damper chamber, and the metal diaphragm on the side facing the bottom wall surface of the damper chamber faces the fuel discharge port. pump. What is described 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 the thing in any one of Claim 1 thru | or 9,
The high-pressure fuel supply pump, wherein the pair of pressing members are fixed by mutual press-fitting and sandwich the metal diaphragm between the two.

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