JP2011220192A - Pulsation damper, and pulsation reducing apparatus and high-pressure pump using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pulsation damper capable of suppressing generation of cracks in a joint portion.SOLUTION: Two diaphragms 51, 61 constituting a pulsation damper 50 include working portions 52, 62 that are elastically deformable by fuel pressure pulsation, recessed grooves 53, 63 recessed from the outer circumferences of the working portions 52, 62 toward a sealed space 300, projection edges 54, 64 projecting from the outer circumferences of the recessed grooves 53, 63 to the outside of the sealed space 300, and cylindrical portions 55, 65 extending from the projection edges 54, 64 to the other diaphragm side. A joint portion 56 is formed by joining faces in an axial direction of the cylindrical portions 55, 65. The radius of curvature R1 in an outer circumference side of the working portions 52, 62, the radius of curvature R2 of the recessed grooves 53, 63, and the radius of curvature R3 of the projection edges 54, 64 are in a relation of R1>R2>R3. This results in gradually increased rigidity, in the order from the working portions 52, 62, the recessed grooves 53, 63 to the projection edges 54, 64, and reduces stress acting on the joint portion 56.

Description

  The present invention relates to a pulsation damper that reduces fuel pressure pulsation, a pulsation reducing device using the pulsation damper, and a high-pressure pump.

Conventionally, a fuel supply system of an internal combustion engine has been provided with a pulsation reducing device that reduces fuel pressure pulsation caused by fuel discharged from a pressurizing chamber to a fuel passage in a metering stroke of a high-pressure pump. In this pulsation reducing device, a pulsation damper is accommodated in a damper chamber communicating with a pressurizing chamber via a fuel passage, and fuel pressure pulsation is reduced by elastic deformation of the pulsation damper. In general, a pulsation damper is formed by joining two metal diaphragms and forming a sealed space in which gas is enclosed.
In the pulsation reducing devices described in Patent Documents 1 and 2, the peripheral portion of the metal diaphragm constituting the pulsation damper is pressed by the support member from the axial direction. Thereby, it is reduced that a stress acts on the junction part of the metal diaphragm located in the radial direction outer side of a supporting member.
In Patent Document 3, a welding bellows is used for the pulsation reducing device. The welded bellows reduces the stress acting on the joints of the individual metal diaphragms by joining a plurality of ring-shaped metal diaphragms in the axial direction.

JP 2004-138071 A Japanese Patent No. 4036153 JP 2000-249018 A

However, in the pulsation reducing devices described in Patent Documents 1 and 2, if the pressing force of the support member is reduced and the peripheral portion of the metal diaphragm is greatly opened in the axial direction, there is a notch inside the diameter of the joint. There is a concern that cracks may develop outward from the portion.
Further, the welding bellows described in Patent Document 3 has a stress intensity factor due to a notch with respect to the axial tensile stress acting on the joint, similar to the pulsation damper described in Patent Documents 1 and 2. Since it is a shape, there is a concern that cracks may develop in the joint. The notch which is a problem in Patent Documents 1, 2, and 3 is called an opening shape (mode I) mainly considering the stress intensity factor.
This invention is made | formed in view of the said problem, and it is providing the pulsation damper which can suppress that a crack arises in a junction part, and a pulsation damping device and high-pressure pump using the same.

According to the first aspect of the present invention, in the pulsation damper provided in the pulsation reducing device for reducing the fuel pressure pulsation of the fuel supply system of the internal combustion engine, the first diaphragm and the second diaphragm are joined, and the first diaphragm and the second diaphragm are joined. A sealed space in which gas is sealed is formed inside the diaphragm. The pulsation damper has a first diaphragm, a second diaphragm, and a joint portion. The first diaphragm includes a first working part that can be elastically deformed by fuel pressure pulsation, a first groove part that is recessed from the outer peripheral side of the first working part to the sealed space side, and from the outer peripheral side of the first groove part to the outside of the sealed space. It has the 1st convex edge part which protrudes, and the cylindrical 1st cylinder part extended from the outer peripheral side of this 1st convex edge part to the 2nd diaphragm side. The second diaphragm includes a second working part that can be elastically deformed by fuel pressure pulsation, a second groove part that is recessed from the outer peripheral side of the second working part to the sealed space side, and from the outer peripheral side of the second groove part to the outside of the sealed space. A protruding second convex edge portion and a cylindrical second cylindrical portion extending from the outer peripheral side of the second convex edge portion to the first diaphragm side are provided. The joining portion is formed by joining the axial surface of the first cylindrical portion of the first diaphragm and the axial surface of the second cylindrical portion of the second diaphragm. The radius of curvature of the outer diameter of the first working part and the second working part is R1, the radius of curvature of the first concave groove part and the second concave groove part is R2, and the radius of curvature of the first convex edge part and the second convex edge part is R3. Then, the relationship between R1, R2, and R3 is R1>R2> R3.
Since the axial surfaces of the first cylindrical portion and the second cylindrical portion of each diaphragm are brought into contact with each other and joined together, a joined portion is formed, so that stress concentration on the joined portion is avoided. That is, the pulsation damper can be formed into a shape that does not have a stress intensity factor because there is no notch in the joint with respect to the tensile stress in the axial direction. Therefore, it is difficult for cracks to occur, and the cracks can be prevented from progressing.
Further, by setting the relationship of R1, R2, and R3 to R1>R2> R3, the first operating portion and the second operating portion have the lowest rigidity, and the first concave groove portion, the second concave groove portion, and the first convex edge portion. And rigidity becomes high in order of the 2nd convex edge part. For this reason, due to the elastic deformation of the pulsation damper, the stress acts most on the first working part and the second working part, and the first concave groove part, the second concave groove part, the first convex edge part, and the second convex edge part. In order, the stress acts small. Thereby, it can suppress that a stress acts on a 1st cylinder part, a 2nd cylinder part, and its junction part.
Furthermore, the deformation | transformation of the radial direction of a 1st cylinder part and a 2nd cylinder part is suppressed by making the rigidity of a 1st convex edge part and a 2nd convex edge part the highest. Therefore, it can prevent that the stress of a junction part becomes excessive.

According to the invention of claim 2, the height between the first working part and the second working part is H1, the height between the first groove part and the second groove part is H2, the first convex edge part and the first Assuming that the height from the two convex edges is H3, the relationship of H1, H2, and H3 is H1>H3> H2.
Since the axial distance between the first tube portion and the second tube portion is shortened due to the relationship of H1> H3, the area where the air pressure in the sealed space acts on the inner walls of the first tube portion and the second tube portion is reduced. In addition, the areas received by the first operating part and the second operating part are larger than the areas of the first cylinder part and the second cylinder part. For this reason, the load which acts on the radial direction of a junction part can be made small.
Further, due to the relationship of H1>H3> H2, when the external pressure becomes high and the first working part and the second working part are elastically deformed and approach each other in the axial direction, the inner walls of the first concave groove part and the second concave groove part are Abut. Therefore, it is possible to prevent stress from acting on the first cylinder part, the second cylinder part, and the joint part by largely deforming the outer diameter part (the part having the curvature radius R1) of the first action part and the second action part. can do. Therefore, it is possible to suppress the occurrence of a load that causes destruction at the joint.

According to the invention which concerns on Claim 3, if the outer diameter of a 1st convex edge part or a 2nd convex edge part is set to Dv and the outer diameter of a junction part is set to Dw, the relationship between Dw and Dv is Dw <Dv.
As a result, when the support member for supporting the pulsation damper is provided outside the pulsation damper and the pulsation damper is installed in the damper chamber of the pulsation reducing device, the contact between the support member and the joint is suppressed. be able to. Therefore, since wear and the like of the joint portion are suppressed, it is possible to suppress a state in which a crack occurs in the joint portion.

  According to the invention of claim 4, the pulsation reducing device reduces the fuel pressure pulsation caused by the fuel discharged to the fuel passage from the pressurizing chamber of the high pressure pump provided in the fuel supply system of the internal combustion engine. The pulsation reducing device includes: a damper housing that forms a damper chamber that communicates with a pressurizing chamber via a fuel passage; the pulsation damper that is housed in the damper chamber; and the pulsation damper that is disposed in the damper chamber. And a support member that supports the device. The pulsation damper has the same operational effects as the invention according to claim 1 described above. For this reason, the pulsation reducing device does not need a protective function of the joint portion in the support member that supports the pulsation damper. Also, since the supporting force to fix the pulsation damper is determined only by pressure pulsation, fuel flow and vibration, the supporting load is small compared to the conventional and there is almost no wear on the part where the pulsation damper support member contacts do not do. Therefore, the pulsation reducing device can increase the degree of freedom in design by simplifying the support member. Moreover, the pulsation reducing device can reduce the man-hours for assembling the pulsation damper and the support member.

  According to the invention of claim 5, the high-pressure pump is provided in the damper chamber, the pump body having the plunger, the pressurizing chamber for pressurizing the fuel by the reciprocating movement of the plunger, and the damper chamber communicating with the pressurizing chamber. The pulsation damper according to claim 1, a suction valve portion that opens or closes a fuel passage between the pressurization chamber and the damper chamber, and a discharge valve portion that discharges fuel pressurized in the pressurization chamber. Prepare. By applying the pulsation damper according to claim 1 to a high-pressure pump, for example, by simplifying the support member of the pulsation damper, the fuel flow in the damper chamber is made smooth, and the pulsation reduction performance of the damper chamber is improved. Can do. Moreover, the assembly man-hour of a pulsation damper and a support member can be reduced.

According to the invention of claim 6, the height between the first working part and the second working part is H1, the height between the first groove part and the second groove part is H2, the first convex edge part and the first Assuming that the height from the two convex edges is H3, the relationship between H1, H2, and H3 is H3>H1> H2.
As a result, when the external pressure is increased and the first operating portion and the second operating portion are elastically deformed and approach each other in the axial direction, the inner walls of the first groove portion and the second groove portion come into contact with each other. Therefore, it is possible to prevent stress from acting on the first cylinder part, the second cylinder part, and the joint part by largely deforming the outer diameter part (the part having the curvature radius R1) of the first action part and the second action part. can do. Therefore, it is possible to suppress the occurrence of a load that causes destruction at the joint.

It is sectional drawing of the pulsation damper by 1st Embodiment of this invention. It is the elements on larger scale of the pulsation damper by a 1st embodiment of the present invention. 1 is a schematic configuration diagram of a fuel supply system of an internal combustion engine to which a pulsation reducing device including a pulsation damper according to a first embodiment of the present invention is applied. It is sectional drawing of a high pressure pump provided with the pulsation damper by 1st Embodiment of this invention. It is the elements on larger scale of FIG. It is the elements on larger scale of the pulsation damper by 2nd Embodiment of this invention. It is the elements on larger scale of the pulsation damper by a 3rd embodiment of the present invention. It is sectional drawing of the pulsation damper and its supporting member by 3rd Embodiment of this invention. It is the elements on larger scale of the pulsation damper by a 4th embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(First embodiment)
1 and 2 show a pulsation damper according to a first embodiment of the present invention, and FIG. 3 shows a schematic configuration diagram of a fuel supply system of an internal combustion engine to which a pulsation reducing device including the pulsation damper is applied. Moreover, the high pressure pump provided with a pulsation damper is shown in FIG. 4, and the partial enlarged view is shown in FIG.

First, the fuel supply system 1 of the internal combustion engine will be described with reference to FIG.
The fuel supply system 1 includes a fuel tank 2, a low pressure pump 3, a high pressure pump 10, a delivery pipe 4, a pulsation reducing device 5, and the like.
The high-pressure pump 10 pressurizes the fuel pumped up from the fuel tank 2 by the low-pressure pump 3 and pumps it to the delivery pipe 4. The high-pressure fuel stored in the delivery pipe 4 is injected into a cylinder of an internal combustion engine (not shown) by an injector 6 connected to the delivery pipe 4.
The high-pressure pump 10 includes a plunger 13 that changes the volume of the pressurizing chamber 121. The plunger 13 is driven by the camshaft 7 via the tappet 9 and pressurizes the fuel in the pressurizing chamber 121 by reciprocating in the axial direction.
The suction valve section 30 of the high-pressure pump 10 opens the fuel passage 100 until a predetermined time when the plunger 13 moves from the bottom dead center to the top dead center, and the fuel in the pressurizing chamber 121 is transferred to the fuel passage 100 on the low-pressure pump 3 side. Discharge. When current is supplied from the controller 8 to the electromagnetic drive unit 70 that drives the intake valve unit 30, the intake valve unit 30 closes the fuel passage 100. Thereby, the amount of fuel pumped from the pressurizing chamber 121 to the delivery pipe 4 is determined.
The pulsation reducing device 5 is provided in the fuel passage 100 on the low pressure pump 3 side of the suction valve unit 30, and reduces fuel pressure pulsation caused by fuel discharged from the pressurizing chamber 121. A pulsation damper 50 is installed in the pulsation reducing device 5.

Next, the basic configuration and operation of the high-pressure pump 10 including the pulsation reducing device 5 will be described with reference to FIGS. 4 and 5.
The high-pressure pump 10 includes a pump body 11, a plunger 13, a pulsation reducing device 5, a suction valve unit 30, an electromagnetic drive unit 70, a discharge valve unit 90, and the like.

The pump body 11 and the plunger 13 will be described.
The pump body 11 is formed with a cylindrical cylinder 14. A plunger 13 is accommodated in the cylinder 14 so as to be capable of reciprocating in the axial direction. The head 17 provided on the opposite side of the plunger 13 from the pressurizing chamber 121 is coupled to the spring seat 18. A spring 19 is provided between the spring seat 18 and an oil seal holder 25 described later. One end of the spring 19 abuts on the oil seal holder 25 and the other end abuts on the spring seat 18 and has a force extending in the axial direction. The spring seat 18 is urged toward the camshaft 7 of the internal combustion engine by the elastic force of the spring 19. As a result, the plunger 13 reciprocates in the axial direction by contacting the cam of the camshaft 7 via the tappet 9. The fuel is pressurized by changing the volume of the pressurizing chamber 121 by the reciprocating movement of the plunger 13.

Next, the pulsation reducing device 5 will be described.
The pulsation reducing device 5 includes a damper housing 203, a lid member 12, a pulsation damper 50, and a support member 40.
The pump body 11 is provided with a bottomed cylindrical damper housing 203 that is recessed in the cylinder side 14 on the opposite side of the cylinder 14. The damper housing 203 opens to the outside of the pump body 11. The lid member 12 closes the opening 204 of the damper housing 203. A damper chamber 200 is formed by the damper housing 203 and the lid member 12.

The damper chamber 200 accommodates a pulsation damper 50 and a support member 40 that supports the pulsation damper 50.
In the pulsation damper 50, two metal diaphragms 51 and 61 are joined, and a sealed space 300 in which a gas of a predetermined pressure is sealed is formed inside the two diaphragms 51 and 61. The air pressure in the sealed space 300 is set to a sealed pressure, for example, 300 kPa, that can correspond to a pressure that suppresses the generation of vapor generated in the fuel at a minimum fuel pressure necessary for engine operation. The spring constant of the pulsation damper 50 is set according to the required durability or other required performance depending on the plate thickness and material of the two metal diaphragms 51 and 61 and the pressure of the fluid sealed in the damper chamber. Is done. And the pulsation frequency and pulsation damping performance which the pulsation damper 50 reduces are determined by this spring constant. Further, the pulsation reduction effect of the pulsation damper 50 varies depending on the volume of the damper chamber 200.
Details of the pulsation damper 50 will be described later.

The support member 40 includes a fixed portion 41 having a substantially U-shaped cross section, a claw portion 42 that extends from an end portion on the opening side of the fixed portion 41, and an upper arm portion 43 that extends from the support portion 41 to the opposite side of the claw portion 42. And the lower arm portion 44 are integrally provided. A plurality of support members 40 are provided in the circumferential direction of the pulsation damper 50.
The fixing part 41 supports the pulsation damper 50 from the outside of the diameter of the pulsation damper 50. The claw portion 42 sandwiches the outer peripheral edge of the pulsation damper 50 from above and below in the axial direction, and prevents the pulsation damper 50 from being detached from the fixed portion 41. The upper arm portion 43 and the lower arm portion 44 are fitted in a first recess 205 and a second recess 206 provided on the inner wall of the damper housing 203, respectively. As a result, the support member 40 fixes the pulsation damper 50 to the damper chamber 200.

  The damper chamber 200 communicates with a fuel inlet (not shown) through a passage (not shown). Fuel is supplied from the fuel tank to the fuel inlet. Accordingly, the fuel in the fuel tank is supplied to the damper chamber 200 from the fuel inlet through the passage.

Next, the suction valve unit 30 will be described.
The pump body 11 is provided with a cylindrical portion 15 substantially perpendicular to the central axis of the cylinder 14. A supply passage 101 is formed inside the cylindrical portion 15. The supply passage 101 communicates with the pressurizing chamber 121 at a deep portion.

  An introduction passage 111 communicates the damper chamber 200 and the supply passage 101. Fuel is supplied to the pressurizing chamber 121 via the passage between the fuel inlet and the damper chamber 200, the damper chamber 200, the introduction passage 111 and the supply passage 101. The passage between the fuel inlet and the damper chamber 200, the introduction passage 111, and the supply passage 101 are passages constituting the fuel passage 100.

The valve body 31 is accommodated in the supply passage 101. The valve body 31 has a small diameter cylindrical portion 32 and a large diameter cylindrical portion 33. A concave tapered valve seat 34 is formed at the bottom of the large diameter cylindrical portion 33.
The suction valve 35 is disposed inside the large diameter cylindrical portion 33 of the valve body 31. The suction valve 35 reciprocates while being guided by the inner wall of the hole provided in the small diameter cylindrical portion 32. On the valve seat 34 side of the intake valve 35, a convex tapered outer peripheral surface that can be seated on the valve seat 34 is formed.

A stopper 39 is fixed to the inner wall of the large diameter cylindrical portion 33 of the valve body 31. The stopper 39 restricts the movement of the suction valve 35 in the valve opening direction (right direction in FIG. 4). A first spring 21 is provided between the inside of the stopper 39 and the suction valve 35. The first spring 21 biases the suction valve 35 in the direction in which the suction valve 35 is seated on the valve seat 34, that is, in the valve closing direction.
In the stopper 39, a plurality of inclined passages 102 that are inclined with respect to the axis of the stopper 39 are formed in the circumferential direction.

Next, the electromagnetic drive unit 70 will be described.
The electromagnetic drive unit 70 includes a coil 71, a fixed core 72, a movable core 73, a flange 75, and the like. The coil 71 is wound around a spool 78 made of resin. The fixed core 72 is made of a magnetic material and is accommodated inside the coil 71. The movable core 73 is made of a magnetic material and is disposed to face the fixed core 72. The movable core 73 is accommodated inside the flange 75 so as to be capable of reciprocating in the axial direction.

The flange 75 is made of a magnetic material and is attached to the cylinder portion 15 of the pump body 11. A cylindrical member 79 made of a nonmagnetic material prevents a magnetic short circuit between the fixed core 72 and the flange 75. The flange 75 holds the fixed core 72 and the connector 77 on the pump body 11 and closes the end of the cylindrical portion 15. A cylindrical guide cylinder 76 is attached to the inner wall of the hole provided in the center of the flange 75.
The needle 38 is formed in a substantially cylindrical shape and reciprocates while being guided by the inner wall of the guide cylinder 76. The needle 38 is installed so that one end thereof is assembled integrally with the movable core 73 and the other end is in contact with the end surface of the suction valve 35 on the electromagnetic drive unit 70 side.

A second spring 22 is provided between the fixed core 72 and the movable core 73. The second spring 22 biases the movable core 73 toward the suction valve 35 with a force stronger than the force that the first spring 21 on the stopper 39 side biases the suction valve 35 in the valve closing direction.
When the coil 71 is not energized, the movable core 73 is not attracted to the fixed core 72 and is separated from each other by the elastic force of the second spring 22. For this reason, the needle 38 integral with the movable core 73 moves to the suction valve 35 side, and the suction valve 35 is opened when the end surface of the needle 38 presses the suction valve 35.

Next, the variable volume chamber 122 will be described.
The plunger 13 has a small-diameter portion 131 on the head 17 side and a large-diameter portion 133 on the pressurizing chamber 121 side. A step surface 132 is formed at a connection portion between the small diameter portion 131 and the large diameter portion 133. A substantially annular plunger stopper 23 is provided at the end of the cylinder 14 so as to face the step surface 132.
The plunger stopper 23 is formed on the end surface on the pressurizing chamber 121 side with a concave portion 231 that is recessed in a substantially disk shape on the opposite side of the pressurizing chamber 121, and a groove 232 that extends from the concave portion 231 to the outer edge of the plunger stopper 23 in the radially outward direction. have. A hole 233 that communicates the plunger stopper 23 in the thickness direction is formed at the center of the plunger stopper 23. In the plunger stopper 23, the small diameter portion 131 of the plunger 13 is inserted into the hole 233. The plunger stopper 23 is in contact with the end face of the pump body 11 at the end face on the pressurizing chamber 121 side.

The pump body 11 is provided with a recess 105 that is recessed in a substantially annular shape toward the pressurizing chamber 121 on the outer wall on the side where the cylinder 14 opens. An oil seal holder 25 is fitted in the recess 105. A small diameter portion 131 of the plunger 13 is inserted through the oil seal holder 25. The oil seal holder 25 is fixed to the inner wall of the recess 105 with a seal member 24 sandwiched between the oil seal holder 25 and the plunger stopper 23. The seal member 24 regulates the thickness of the fuel oil film around the small diameter portion 131 and suppresses fuel leakage to the engine due to the sliding of the plunger 13. An oil seal 26 is mounted on the end of the oil seal holder 25 opposite to the pressurizing chamber 121. The oil seal 26 regulates the thickness of the oil film around the small-diameter portion 131 and suppresses oil leakage due to the sliding of the plunger 13.
The variable volume chamber 122 is formed by a space surrounded by the stepped surface 132 of the plunger 13, the outer wall of the small diameter portion 131, the inner wall of the cylinder 14, the concave portion 231 of the plunger stopper 23, and the seal member 24.

  Between the oil seal holder 25 and the pump body 11, a tubular passage 106 and an annular passage 107 communicating with the tubular passage 106 are formed. The cylindrical passage 106 communicates with the groove 232 of the plunger stopper 23. The annular passage 107 communicates with the damper chamber 200 via a return passage 108 formed in the pump body 11. In this manner, the variable volume chamber 122 and the damper chamber 200 communicate with each other by sequentially communicating the groove 232, the cylindrical passage 106, the annular passage 107, and the return passage 108.

The volume of the variable volume chamber 122 changes according to the reciprocation of the plunger 13.
When the plunger 13 is raised during the metering stroke, the volume of the pressurizing chamber 121 is decreased and the volume of the variable volume chamber 122 is increased. Here, the cross-sectional area ratio between the large diameter portion 133 and the variable volume chamber 122 is approximately 1: 0.6. Therefore, the ratio of the decrease in the volume of the pressurizing chamber 121 to the increase in the volume of the variable volume chamber 122 is also 1: 0.6. Therefore, about 60% of the volume of the low-pressure fuel discharged from the pressurizing chamber 121 to the damper chamber 200 side passes through the return passage 108, the annular passage 107, the cylindrical passage 106, and the groove 232 from the damper chamber 200. Inhaled into chamber 122. Thereby, transmission of fuel pressure pulsation is reduced by about 60%.

  On the other hand, when the plunger 13 is lowered during the suction stroke, the volume of the pressurizing chamber 121 is increased and the volume of the variable volume chamber 122 is decreased. Accordingly, the fuel in the variable volume chamber 122 is sent out to the damper chamber 200 at the same time that the pressurizing chamber 121 sucks the fuel from the damper chamber 200. At this time, about 60% of the fuel sucked into the pressurizing chamber 121 is supplied from the variable volume chamber 122, and the remaining about 40% is sucked from the fuel inlet. Thereby, the fuel suction efficiency into the pressurizing chamber 121 is improved.

Next, the discharge valve unit 90 will be described.
The discharge valve unit 90 allows or blocks the discharge of the fuel pressurized in the pressurizing chamber 121. The discharge valve portion 90 includes a discharge valve 92, a regulating member 93, a spring 94, and the like.
A discharge passage 114 is formed in the pump body 11 substantially perpendicular to the central axis of the cylinder 14. The discharge passage 114 communicates the pressurizing chamber 121 and the fuel outlet 91.
The discharge valve 92 is formed in a bottomed cylindrical shape and is accommodated in the discharge passage 114 so as to be reciprocally movable. The discharge valve 92 closes the discharge passage 114 by being seated on a valve seat 95 formed in the discharge passage 114, and opens the discharge passage 114 by being separated from the valve seat 95.
A cylindrical regulating member 93 provided on the fuel outlet 91 side of the discharge valve 92 is fixed to the inner wall of the discharge passage 114. The restricting member 93 restricts the movement of the discharge valve 92 toward the fuel outlet 91.
One end of the spring 94 is in contact with the regulating member 93 and the other end is in contact with the discharge valve 92. The spring 94 urges the discharge valve 92 toward the pressurizing chamber 121 side.

When the fuel pressure in the pressurizing chamber 121 rises and the force received by the discharge valve 92 from the fuel on the pressurizing chamber 121 side becomes greater than the sum of the elastic force of the spring 94 and the force received from the fuel on the fuel outlet 91 side, the discharge valve 92 is separated from the valve seat 95. Thereby, the fuel in the pressurizing chamber 121 is discharged from the fuel outlet 91 to the outside of the high-pressure pump 10.
On the other hand, when the fuel pressure in the pressurizing chamber 121 decreases and the force received by the discharge valve 92 from the fuel on the pressurizing chamber 121 side becomes smaller than the sum of the elastic force of the spring 94 and the force received from the fuel on the fuel outlet 91 side, The discharge valve 92 is seated on the valve seat 95. This prevents the fuel on the fuel outlet 91 side from flowing back to the pressurizing chamber 121.

Next, the operation of the high-pressure pump 10 will be described.
(1) Suction stroke When the plunger 13 descends from the top dead center toward the bottom dead center, the fuel in the pressurizing chamber 121 is depressurized. At this time, the energization to the coil 71 is stopped, the suction valve 35 is opened, and the supply passage 101 and the pressurizing chamber 121 communicate with each other. On the other hand, the discharge valve 92 is seated on the valve seat 95 and closes the discharge passage 114. As a result, the fuel in the damper chamber 200 is sucked into the pressurizing chamber 121 via the supply passage 101. At this time, the operating portions 52 and 62 of the first diaphragm 51 and the second diaphragm 61 expand, thereby exhibiting an effect of suppressing fuel reduction in the damper chamber volume and assisting fuel suction.

(2) Metering stroke When the plunger 13 rises from the bottom dead center toward the top dead center, the energization to the coil 71 is stopped until the predetermined time, and the suction valve 35 maintains the valve open state. For this reason, the low pressure fuel in the pressurizing chamber 121 is returned to the damper chamber 200 via the supply passage 101. At this time, the operation parts 52 and 62 of the first diaphragm 51 and the second diaphragm 61 contract, thereby exhibiting an effect of suppressing an increase in fuel in the damper chamber volume.

  When current is supplied from the terminal 74 of the connector 77 to the coil 71 at a predetermined time during the metering process, a magnetic attractive force is generated between the fixed core 72 and the movable core 73 by the magnetic field generated in the coil 71. When this magnetic attraction force becomes larger than the difference between the elastic force of the second spring 22 and the elastic force of the first spring 21, the movable core 73 and the needle 38 integrated with the movable core 73 move to the fixed core 72 side. Then, the suction valve 35 and the needle 38 are separated from each other, and the suction valve 35 is controlled by the force generated by the elastic force of the first spring 21 and the flow of low-pressure fuel discharged from the pressurizing chamber 121 to the damper chamber 200 side. Move to the seat 34 side. As a result, the intake valve 35 is seated on the valve seat 34 and is closed.

  When the intake valve 35 is closed, the fuel flow in the supply passage 101 is shut off, and the metering process for returning the low-pressure fuel from the pressurizing chamber 121 to the damper chamber 200 ends. That is, by adjusting the energization time of the coil 71, the amount of low-pressure fuel returned from the pressurizing chamber 121 to the damper chamber 200 is adjusted. Thereby, the amount of fuel pressurized in the pressurizing chamber 121 is determined.

(3) Pressurization stroke When the flow of fuel between the pressurization chamber 121 and the damper chamber 200 is interrupted and the plunger 13 rises further toward the top dead center, the fuel pressure in the pressurization chamber 121 is increased. To rise. When the fuel pressure in the pressurizing chamber 121 exceeds a predetermined pressure, the discharge valve 92 opens against the elastic force of the spring 94 and the fuel pressure on the fuel outlet side. As a result, the fuel pressurized in the pressurizing chamber 121 is discharged from the fuel outlet 91 via the discharge passage 114.

When the plunger 13 rises to the top dead center, the energization to the coil 71 is stopped, and the suction valve 35 is opened again. Then, the plunger 13 descends again, and the suction stroke is performed again.
Thus, by repeating the steps (1) to (3), the high-pressure pump 10 pressurizes and discharges the sucked fuel.

Next, the pulsation damper 50 installed in the pulsation reducing device 5 will be described in detail with reference to FIGS. 1 and 2.
The first diaphragm 51 has a first working part 52, a first concave groove part 53, a first convex edge part 54, and a first cylindrical part 55, and is a metal plate press that is not affected by corrosive substances and has a high elastic modulus. It is formed by processing.
The first actuating portion 52 serving as an actuating region has a substantially disc-shaped disc portion 521 at the center and a curved surface portion 522 around the disc portion 521, and is formed in a substantially dome shape.
The first groove portion 53 is formed in an arc shape whose longitudinal section is recessed toward the sealed space 300, and is provided in an annular shape on the outer peripheral side of the first operating portion 52.
The first convex edge portion 54 is formed in an arc shape whose longitudinal section protrudes to the outside of the sealed space 300, and is provided annularly on the outer peripheral side of the first concave groove portion 53.
The 1st cylinder part 55 is extended from the outer peripheral side of the 1st convex edge part 54 to the 2nd diaphragm 61 side, and is formed in the cylinder shape.
The radius of curvature of the curved surface portion 522 of the first operating portion 52 is R1, the radius of curvature of the first concave groove portion 53 is R2, and the radius of curvature of the first convex edge portion 54 is R3. The first diaphragm 51 is formed such that the curvature radii of the curved surface portion 522, the first concave groove portion 53, and the first convex edge portion 54 of the first operating portion 52 are R1>R2> R3.

  The second diaphragm 61 includes a second operating part 62, a second groove part 63, a second convex edge part 64, and a second cylinder part 65. The configuration of the second operating portion 62, the second concave groove portion 63, the second convex edge portion 64 and the second cylindrical portion 65 of the second diaphragm 61 is the same as the first operating portion 52 and the first concave groove portion of the first diaphragm 51 described above. 53, the first convex edge portion 54 and the first cylindrical portion 55 are substantially the same.

  The height between the first operating part 52 and the second operating part 2 is H1, the height between the first concave groove part 53 and the second concave groove part 63 is H2, and the first convex edge part 54 and the second convex edge part. The height of 64 is H3. The pulsation damper 50 is formed so that these heights satisfy H1> H3> H2. In addition, it is formed so that H2> 0, and the first groove portion 53 and the second groove portion 63 are elastically deformable in the axial direction.

The axial surface of the first cylindrical portion 55 of the first diaphragm 51 and the axial surface of the second cylindrical portion 65 of the second diaphragm 61 are brought into contact with each other, and are joined by laser welding or the like, whereby the joint portion 56 is formed. It is formed. In the sealed space 300 formed inside the first diaphragm 51 and the second diaphragm 61, an enclosed pressure of 300 kPa, for example, corresponding to a pressure that suppresses the generation of vapor generated in the fuel above the minimum fuel pressure necessary for engine operation. Gas is enclosed.
Since the pulsation damper 50 having the above-described shape has a large area of the first operating part 52 and the second operating part, an axial tensile stress acts predominantly on the joint part 56 due to the atmospheric pressure of the sealed space 300. With respect to the tensile stress in the axial direction, since the first cylindrical portion 55 and the second cylindrical portion 65 extend in the axial direction from the joint portion 56, stress concentration on the joint portion 56 is avoided. Therefore, the pulsation damper 50 has a shape in which there is no stress intensity factor because the joint 56 has no notch with respect to the axial tensile stress. Therefore, it is difficult for cracks to occur in the joint portion 56, and the cracks can be prevented from progressing.

The pulsation damper 50 of the present embodiment is configured such that the first operating part 52 and the second operating part 62 are elastically deformed in accordance with the fuel pressure pulsation of the damper chamber 200 in which the pulsation damper 50 is provided, so that the volume of the damper chamber 200 is increased. Variable to reduce fuel pressure pulsation. At this time, the first diaphragm 51 is formed such that the radii of curvature of the first curved surface portion 522, the first concave groove portion 53, and the first convex edge portion 54 of the first operating portion 52 satisfy R1>R2> R3. Therefore, the rigidity of the 1st operation part 52 is the lowest, and rigidity is high in order of the 1st ditch part 53 and the 1st convex edge part 54. Similarly to the first diaphragm 51, the second diaphragm 61 has the lowest rigidity in the second diaphragm 61, and the second groove portion 63 and the second convex edge portion 64 have higher rigidity in this order. For this reason, when the 1st operation part 52 and the 2nd operation part 62 elastically deform, vibration is generated in the 1st curved surface part 522 of the 1st operation part 52 and the 2nd curved surface part 622 of the 2nd operation part 62 with low rigidity. Most absorbed. Therefore, the largest stress is applied to the first operating portion 52 and the second operating portion 62, and the stress is applied in the order of the first concave groove portion 53, the second concave groove portion 63, the first convex edge portion 54, and the second convex edge portion 64. Acts small. Thereby, it is suppressed that a stress acts on the 1st cylinder part 55, the 2nd cylinder part 65, and its junction part 56. FIG.
Furthermore, the radial deformation of the first cylindrical portion 55 and the second cylindrical portion 65 is suppressed by making the rigidity of the first convex edge portion 54 and the second convex edge portion 64 the highest. Therefore, it can prevent that the stress of the junction part 56 becomes excessive.

In the pulsation damper 50 of the present embodiment, the fuel pressure in the damper chamber 200 is increased due to the relationship of H1>H3> H2, and the first operating part 52 and the second operating part 62, as well as the first concave groove part 53 and the second concave part. When the groove 63 is elastically deformed and approaches each other in the axial direction, the inner wall of the first groove 53 and the inner wall of the second groove 63 abut. Therefore, the curved surface portion 522 of the first operating portion 52 and the curved surface portion 622 of the second operating portion 62 are greatly elastically deformed, so that the first convex edge portion 54, the first cylindrical portion 55, the second convex edge portion 64, Elastic deformation of the two cylinder portions 65 is suppressed. Therefore, it can suppress that a stress acts on the junction part 56. FIG.
In addition, due to the relationship of H1> H3, the area where the first operating part 52 and the second operating part 62 receive the pressure of the sealed space 300 is the same as that of the first cylinder part 55 and the second cylinder part 65. It is larger than the area to receive pressure. For this reason, the load which acts on the radial direction of the junction part 56 can be made small. Therefore, it is possible to suppress the occurrence of cracks in the joint portion 56.

(Second Embodiment)
A pulsation damper according to a second embodiment of the present invention is shown in FIG.
The pulsation damper 501 of the present embodiment is formed such that the curvature radius R4 of the first convex edge portion 541 is smaller than the curvature radius R3 of the first embodiment. Similarly, the radius of curvature of the second convex edge portion 641 is formed to be smaller than the radius of curvature R3 of the first embodiment.
Further, the height H4 of the first convex edge portion 541 and the second convex edge portion 641 is formed closer than the height H3 of the first embodiment.

By forming the curvature radius R4 of the first convex edge portion 541 and the second convex edge portion 641 small, the rigidity of the first convex edge portion 541 and the second convex edge portion 641 can be increased. Thereby, the elastic deformation of the 1st cylinder part 551 and the 2nd cylinder part 652 at the radial direction can be suppressed, and it can suppress that the stress which acts on the junction part 56 becomes excessive.
In addition, the first cylindrical portion 551, the second cylindrical portion 652, and the joining portion 56 receive the pressure of the sealed space 300 by reducing the height H 4 between the first convex edge portion 541 and the second convex edge portion 641. The area to be applied can be further reduced, and the load acting in the radially outward direction of the joint portion 56 can be reduced. Therefore, it is possible to reliably suppress the occurrence of cracks in the joint portion 56.

(Third embodiment)
A pulsation damper according to a third embodiment of the present invention is shown in FIGS.
In the pulsation damper 502 of the present embodiment, the joining portion 56 side of the first tubular portion 552 and the joining portion 56 side of the second tubular portion 652 are joined so as to be inclined inward in the radial direction. For this reason, the outer diameter Dv of the 1st convex edge part 54 and the said 2nd convex edge part 64 and the outer diameter Dw of a junction part have the relationship of Dw <Dv.
For this reason, it can suppress that the inner wall of the fixing | fixed part 41 of the supporting member 40 and the junction part 56 contact | abut. Therefore, since wear and the like of the joint portion 56 are suppressed, it is possible to suppress a state in which a crack occurs in the joint portion 56.
Since the support force required for the support member 40 of the present embodiment to fix the pulsation damper 502 is determined only by the pressure pulsation and fuel flow of the damper chamber 200 and the vibration of the pulsation damper 502, the conventional support member It becomes small compared with the supporting force required for 40. For this reason, there is almost no wear of the part which the support member 40 of the pulsation damper 502 contacts. Therefore, the durability of the pulsation damper 502 can be improved.
Further, since the support member 40 does not need the protection function of the joint portion 56 of the pulsation damper 502, the degree of freedom in designing the support member 40 can be increased. Moreover, the assembly man-hour of the pulsation damper 502 and the support member 40 can be reduced.

(Fourth embodiment)
FIG. 9 shows a partially enlarged view of the pulsation damper according to the fourth embodiment of the present invention.
The pulsation damper 503 of the present embodiment includes a height H1 between the first operating portion 52 and the second operating portion 2, a height H2 between the first concave groove portion 53 and the second concave groove portion 63, and a first convex edge. The relationship of the height H3 between the portion 54 and the second convex edge portion 64 is formed such that H3>H1> H2.
Moreover, H1 = H3> H2 may be sufficient. In addition, it is formed so that it may become H2> 0, and the curvature radius of the curved surface part 522 of the 1st action | operation part 52, the 1st groove part 53, and the 1st convex edge part 54 will be set to R1>R2> R3. It is the same as in the first to third embodiments described above.
Also in the present embodiment, the fuel pressure in the damper chamber 200 in which the pulsation damper 503 is provided is increased, and the first operating portion 52 and the second operating portion 62, and the first and second concave groove portions 53 and 63 are elastically deformed. When approaching each other in the axial direction, the inner wall of the first groove portion 53 and the inner wall of the second groove portion 63 abut. Therefore, the curved surface portion 522 of the first operating portion 52 and the curved surface portion 622 of the second operating portion 62 are elastically deformed, so that the first convex edge portion 54, the first cylindrical portion 55, the second convex edge portion 64, the second Elastic deformation of the cylindrical portion 65 is suppressed. Therefore, it can suppress that a stress acts on the junction part 56. FIG.
In the present embodiment, the physics damper 503 can be made smaller in the axial direction. Therefore, the volume of the damper chamber 200 can be effectively used to increase the degree of freedom in designing the pulsation reducing device.

(Other embodiments)
In the plurality of embodiments described above, the first diaphragm 51 forms the first concave groove portion 53 once on the outer peripheral side of the first operating portion 52, and the first convex edge portion 54 on the outer peripheral side of the first concave groove portion 53. Was formed once. On the other hand, in the present invention, a plurality of first concave groove portions and first convex edge portions may be formed in the first diaphragm. Similarly, the second diaphragm may be formed with a plurality of second concave groove portions and second convex edge portions.
In the plurality of embodiments described above, the disc portion 521 is provided in the central portion of the first operating portion 52 that is the operating region, and the curved surface portion 522 is provided around the disc portion 521. On the other hand, in the present invention, the disk portion of the first operating portion may be formed in a wave shape. Similarly, the disk part of the second working part may be formed in a wave shape.
In the plurality of embodiments described above, the pulsation damper 50 is installed in the damper chamber 200 via the support member 40. In contrast, in the present invention, the support member may be formed integrally with the damper housing or the lid member without using the support member, and the pulsation damper may be fixed to the damper housing or the lid member.
In the plurality of embodiments described above, the high-pressure pump 10 and the pulsation reducing device 5 are configured integrally. On the other hand, in the present invention, the high pressure pump and the pulsation reducing device may be configured separately, and the pulsation reducing device may be provided in the fuel passage or the low pressure fuel pipe between the suction valve portion of the high pressure pump and the low pressure pump. .
Thus, the present invention is not limited to the above-described embodiments, and can be implemented in various forms without departing from the spirit of the invention.

  50: Pulsation damper, 51: 1st diaphragm, 52: 1st operation part, 53: 1st groove part, 54: 1st convex edge part, 55: 1st cylinder part, 56: Joint part, 61: 2nd Diaphragm, 62: 2nd operation part, 63: 2nd groove part, 64: 2nd convex edge part, 65: 2nd cylinder part, 200: Sealed space

Claims (6)

A sealed space provided in a pulsation reducing device for reducing fuel pressure pulsation in a fuel supply system of an internal combustion engine, in which a first diaphragm and a second diaphragm are joined, and gas is sealed inside the first diaphragm and the second diaphragm. Is a pulsation damper formed,
A first working part that can be elastically deformed by fuel pressure pulsation, a first groove part that is recessed from the outer peripheral side of the first working part to the sealed space side, and a first part that protrudes outside the sealed space from the outer peripheral side of the first groove part. A first diaphragm having a first convex edge portion and a cylindrical first cylindrical portion extending from the outer peripheral side of the first convex edge portion to the second diaphragm side;
A second working part that can be elastically deformed by fuel pressure pulsation, a second recessed groove part that is recessed from the outer peripheral side of the second working part to the sealed space side, and a second projecting part from the outer peripheral side of the second recessed groove part to the outside of the sealed space. A second diaphragm having two convex edges and a cylindrical second cylinder extending from the outer peripheral side of the second convex edge to the first diaphragm;
A joining portion formed by joining an axial surface of the first cylindrical portion of the first diaphragm and an axial surface of the second cylindrical portion of the second diaphragm;
The radius of curvature of the outer periphery side of the first working part and the second working part is R1, the radius of curvature of the first concave groove part and the second concave groove part is R2, the first convex edge part and the second convex edge part. The pulsation damper is characterized in that the relation of R1, R2, and R3 is R1>R2> R3, where R3 is a radius of curvature.   The height between the first working part and the second working part is H1, the height between the first groove part and the second groove part is H2, the first convex edge part and the second convex edge. 2. The pulsation damper according to claim 1, wherein the relationship between H <b> 1, H <b> 2, and H <b> 3 is H <b> 1> H <b> 3> H <b> 2.   The relationship between Dw and Dv is Dw <Dv, where Dv is an outer diameter of the first convex edge portion or the second convex edge portion and Dw is an outer diameter of the joint portion. The pulsation damper according to 1 or 2. A pulsation reducing device for reducing fuel pressure pulsation caused by fuel discharged from a pressurizing chamber of a high pressure pump provided in a fuel supply system of an internal combustion engine to a fuel passage,
A damper housing forming a damper chamber communicating with the pressurizing chamber via the fuel passage;
The pulsation damper as described in any one of Claims 1-3 accommodated in the said damper chamber,
And a support member for supporting the pulsation damper in the damper chamber. A high pressure pump provided in a fuel supply system of an internal combustion engine,
A plunger driven by rotation of a camshaft of the internal combustion engine;
A pump body having a pressurizing chamber for pressurizing fuel by reciprocating movement of the plunger, and a damper chamber communicating with the pressurizing chamber;
The pulsation damper as described in any one of Claims 1-3 provided in the said damper chamber,
A suction valve portion that opens or closes a fuel passage between the pressurizing chamber and the damper chamber and adjusts the amount of fuel pressurized in the pressurizing chamber;
A high-pressure pump comprising: a discharge valve portion that discharges fuel pressurized in the pressurizing chamber.   The height between the first working part and the second working part is H1, the height between the first groove part and the second groove part is H2, the first convex edge part and the second convex edge. 2. The pulsation damper according to claim 1, wherein the relationship between H <b> 1, H <b> 2, and H <b> 3 is H <b> 3> H <b> 1> H <b> 2.

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