JP2015078701A - High pressure pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high pressure pump capable of reducing operation noise.SOLUTION: A pump body 11 has a pressurization chamber 121 for pressurizing a fuel by reciprocating motion of a plunger 13, and a damper chamber 201 for reducing pressure pulsation of the fuel discharged from the pressurization chamber 121. A cover 50 for blocking the damper chamber 201 from the outside air, projects more to an outside air side at its central portion 52 than at a peripheral portion 53. A pulsation damper 210 disposed in the damper chamber 201 is supported by first and second supporting members 211, 212. Thus, radiation noise generated from the cover 50 can be reduced.

Description

  The present invention relates to a high-pressure pump used for an internal combustion engine.

Conventionally, a high-pressure pump that is provided in a fuel supply system that supplies fuel to an internal combustion engine and pressurizes the fuel is known. The fuel pumped up from the fuel tank and supplied to the high-pressure pump is sucked into the pressurizing chamber when the plunger of the high-pressure pump is lowered, and is metered and pressurized when the plunger is raised. When the plunger moves up, the high-pressure pump discharges a part of the fuel sucked into the pressurizing chamber into the supply passage on the fuel inlet side. As a result, the amount of fuel pressurized and fed from the high pressure pump to the internal combustion engine is adjusted.
A damper chamber for reducing pressure pulsation of fuel discharged from the pressurizing chamber to the fuel inlet side is formed in the pump body of the high-pressure pump. In the high-pressure pump of Patent Document 1, a recess is provided on the opposite side of the pump body from the cylinder, and a damper chamber is formed by closing the opening of the recess with a bottomed cylindrical cover.
In the high-pressure pumps described in Patent Documents 2 and 3, the cover that forms the damper chamber is provided with irregularities by pressing or the like. This increases the rigidity of the cover.

JP 2006-307829 A JP 2008-286144 A Germany 102004047601A1 specification

By the way, the vibration of the high-pressure pump, which is driven by opening / closing of the suction valve provided in the high-pressure pump, reciprocation of the plunger, fuel pressure pulsation, or driving of the internal combustion engine, is transmitted. In the high-pressure pump of Patent Document 1, the bottom of the bottomed cylindrical cover is formed in a thin flat surface, so that vibrations transmitted to the cover oscillate air and emit radiated sound from the cover. . There is a concern that the operating noise of the high-pressure pump may increase due to this radiated sound.
When the rigidity of the cover is increased by bending the bottom of the cover by press working or the like as in the high-pressure pumps of Patent Documents 2 and 3, the amount of displacement of the cover with respect to vibration, that is, the vibration amplitude decreases, but the natural frequency increases.
In general, it is known that the vibration acceleration of an object is proportional to the square of the natural frequency and the vibration amplitude. For this reason, although the cover of the high-pressure pump described in Patent Documents 2 and 3 has a small vibration amplitude of the cover, the natural frequency of the cover is large, so it is difficult to reduce the vibration acceleration. Therefore, it is difficult to reduce the operating noise of the high-pressure pump due to the radiated sound emitted from the cover.
The present invention has been made in view of the above problems, and an object thereof is to provide a high-pressure pump capable of reducing operating noise.

According to the invention of claim 1, the pump body has the pressurizing chamber in which the fuel is pressurized by the reciprocating movement of the plunger. The intake valve portion opens or blocks the supply passage through which the fuel supplied to the pressurizing chamber flows. The discharge valve portion opens or blocks a discharge passage through which fuel discharged from the pressurizing chamber flows. The cover that covers the pump body and is welded to the pump body blocks the fuel in the damper chamber that reduces the pressure pulsation of the fuel discharged from the pressurizing chamber to the supply passage from the outside air. As for the cover, the center part of the cover protrudes to the outside air side from the peripheral part.
The pulsation damper is provided in the damper chamber to reduce fuel pressure pulsation. The first support member supports the pulsation damper from the pump body side of the pulsation damper. The second support member supports the pulsation damper from the side opposite to the pump body of the pulsation damper.

It is sectional drawing of the high pressure pump by 1st Embodiment of this invention. It is sectional drawing of the cover of the high pressure pump by 1st Embodiment of this invention. FIG. 3 is an arrow view in the III direction of FIG. 2. It is sectional drawing of the cover of the high pressure pump by 2nd Embodiment of this invention. It is an arrow view of the V direction of FIG. It is sectional drawing of the cover of the high pressure pump by 3rd Embodiment of this invention. It is sectional drawing of the cover of the high pressure pump by 4th Embodiment of this invention. It is sectional drawing of the cover of the high pressure pump by 5th Embodiment of this invention. It is sectional drawing of the cover of the high pressure pump by 6th Embodiment of this invention. It is sectional drawing of the cover of the high pressure pump by 7th Embodiment of this invention. It is sectional drawing of the cover of the high pressure pump by 8th Embodiment of this invention.

Hereinafter, a plurality of embodiments of the present invention will be described with reference to the drawings.
(First embodiment)
A high-pressure pump according to a first embodiment of the present invention is shown in FIGS. The high-pressure pump 10 of this embodiment is provided in a fuel supply system that supplies fuel to an internal combustion engine. The fuel pumped up from the fuel tank is pressurized by the high-pressure pump 10 and accumulated in the delivery pipe. The fuel is injected and supplied to each cylinder of the internal combustion engine from an injector connected to the delivery pipe.

The high-pressure pump 10 includes a pump body 11, a plunger 13, a damper chamber 201, 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.
A cylindrical cylinder 14 is formed in the pump body 11. A plunger 13 is accommodated in the cylinder 14 so as to be capable of reciprocating in the axial direction. The plunger 13 is provided so as to face the pressurizing chamber 121 formed in the deep part of the cylinder 14. 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 the oil seal holder 25. Due to the elastic force of the spring 19, the spring seat 18 is urged toward the camshaft of the engine (not shown). Thereby, the plunger 13 reciprocates in the axial direction by contacting the cam of the camshaft via a tappet (not shown). By the reciprocating movement of the plunger 13, the volume of the pressurizing chamber 121 is changed to suck and pressurize the fuel.

Next, the damper chamber 201 and the cover 50 will be described.
The pump body 11 is provided with a recess 203 that is recessed in the cylinder side 14 on the opposite side of the cylinder 14. A cylindrical tube portion 205 protruding in the axial direction is provided at the periphery of the recess 203. The damper chamber 201 is formed by covering the cylindrical portion 205 with the bottomed cylindrical cover 50. The cover 50 blocks the damper chamber 201 from the outside air.

The cover 50 is formed from, for example, ferritic stainless steel by forging and cutting. The cover 50 includes a central portion 52, a peripheral portion 53 outside the central portion 52, and a connecting portion 51 that extends in a cylindrical shape from the outer edge of the peripheral portion 53. The connecting part 51 is fixed to the cylinder part 205 of the pump body 11. The peripheral portion 53 extends radially inward from the opposite side of the connecting portion 51 to the axial pump body 11. The central part 52 is located in the radial direction of the peripheral part 53.
In FIG. 2, the central portion 52, the peripheral portion 53, and the connection portion 51 are conceptually divided by broken lines, but in the present embodiment, the cover 50 is integrally formed.

The step portion 54 formed in the connection portion 51 abuts on the end surface of the cylindrical portion 205 in the axial direction. The inner wall in the radially inner direction of the connecting portion 51 and the outer wall in the radially outer direction of the cylindrical portion 205 are fixed by welding from the outer diameter side of the connecting portion 51. In the connecting portion 51, the thickness on the opposite side of the stepped portion 54 to the peripheral portion in the axial direction is formed thinner than the thickness t <b> 2 on the peripheral portion side in the axial direction. Thereby, the welding process from the diameter outer side of the connection part 51 becomes easy.
The wall thickness t1 of the peripheral portion 53 is formed to be thicker than the wall thickness t2 of the connection portion 51 on the peripheral side in the axial direction. As a result, the rigidity of the entire cover 50 is increased and the mass is increased.
The inner wall of the central portion 52 protrudes in a substantially cylindrical shape toward the damper chamber 201 from the inner wall of the peripheral portion 53. Accordingly, the thickness t3 of the central portion 52 is thicker than the thickness t1 of the peripheral portion 53. The mass of the central portion 52 is adjusted by setting the diameter D1 and the thickness t3 of the central portion 52. The diameter D1 and thickness t3 of the central portion 52 and the thickness t1 of the peripheral portion 53 are set so that the radiated sound emitted from the cover 50 is reduced by experiments or the like.

In the damper chamber 201, a pulsation damper 210, a first support member 211, a second support member 212, and a wave spring 213 are accommodated.
The pulsation damper 210 is composed of two metal diaphragms, and a gas having a predetermined pressure is sealed therein. The pulsation damper 210 reduces the fuel pressure pulsation in the damper chamber 201 by elastically deforming the two metal diaphragms in accordance with the pressure change in the damper chamber 201.
The first support member 211 and the second support member 212 are formed in a cylindrical shape, and sandwich the pulsation damper 210 from above and below. The first support member 211 is fitted in the hole 110 provided in the recess 203. As a result, the first support member 211 is restricted from moving in the radial direction.
The wave spring 213 is provided between the second support member 212 and the cover 50. The wave spring 213 presses the second support member 212 toward the hole 110 side of the recess 203. As a result, the second support member 212, the pulsation damper 210, and the first support member 211 are fixed in the damper chamber 201.
The first support member 211 has a hole through which fuel passes in the radial direction. As a result, fuel flows inside and outside the first support member 211.

  The damper chamber 201 communicates with a fuel inlet (not shown) through a fuel passage (not shown). Fuel is supplied to the fuel inlet from a fuel tank (not shown). Therefore, the damper chamber 201 is supplied with fuel in the fuel tank from the fuel inlet through the fuel 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. The valve body 31 is accommodated inside the cylindrical portion 15 and is fixed by the locking member 20. A first valve seat 34 having a concave tapered circumferential surface is formed inside the valve body 31.
The suction valve 35 is disposed inside the valve body 31. The suction valve 35 reciprocates while being guided by the inner wall of a hole provided in the bottom of the valve body 31. The intake valve 35 opens the supply passage 100 by being separated from the first valve seat 34, and closes the supply passage 100 by being seated on the first valve seat 34.

The stopper 40 is fixed to the inner wall of the valve body 31. The stopper 40 restricts the movement of the intake valve 35 in the valve opening direction (right direction in FIG. 1). A first spring 21 is provided between the inside of the stopper 40 and the end face of the suction valve 35. The first spring 21 biases the suction valve 35 in the valve closing direction (left direction in FIG. 1).
A plurality of inclined passages 102 that are inclined with respect to the axis of the stopper 40 are formed in the stopper 40 in the circumferential direction. The fuel flows through the inclined passage 102 and through the pressurizing chamber 121 and the passage inside the valve body 31.

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 generates a magnetic field when energized through the terminal 74 of the connector 77. 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. The flange 75 holds the electromagnetic drive unit 70 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 cylindrical member 79 made of a nonmagnetic material prevents a magnetic short circuit between the fixed core 72 and 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. One end of the needle 38 is fixed to the movable core 73, and the other end can be brought into 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 in the valve closing direction with a force stronger than the force that the first spring 21 biases the suction valve 35 in the valve closing direction.
When the coil 71 is not energized, the movable core 73 and the fixed core 72 are separated from each other by the elastic force of the second spring 22. As a result, the needle 38 integrated with the movable core 73 moves toward the suction valve 35, 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 part 131 and a large diameter part 133. 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 so as to face the step surface 132.
The plunger stopper 23 is in contact with the pump body 11 at the end surface on the pressurizing chamber 121 side. The plunger 13 is inserted through a hole 233 provided in the central portion of the plunger stopper 23. The plunger stopper 23 has a plurality of grooves 232 extending radially in the radial direction.
A variable volume chamber 122 is formed by a substantially annular space surrounded by the step surface 132 of the plunger 13, the outer wall of the small diameter portion 131, the inner wall of the cylinder 14, the plunger stopper 23 and the seal member 24.

  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. The oil seal holder 25 is fixed to the pump body 11 with a seal member 24 sandwiched between the plunger stopper 23 and the oil seal holder 25. 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.

  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 201 via a return passage 108 formed in the pump body 11. In this way, the variable volume chamber 122 and the damper chamber 201 communicate with each other by sequentially communicating the groove 232, the cylindrical passage 106, the annular passage 107, and the return passage 108.

Next, the discharge valve unit 90 will be described.
The discharge valve unit 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 the second valve seat 95, and opens the discharge passage 114 by being separated from the second 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 second valve seat 95 formed on the inner wall of the discharge passage 114.

The pressure of the fuel in the pressurizing chamber 121 rises, and the force received by the discharge valve 92 from the fuel on the pressurizing chamber 121 side is the sum of the elastic force of the spring 94 and the force received from the fuel on the downstream side of the second valve seat 95. Becomes larger, the discharge valve 92 is separated from the second valve seat 95. As a result, the fuel is discharged from the fuel outlet 91 through the discharge passage 114 from the pressurizing chamber 121.
On the other hand, the pressure of the fuel in the pressurizing chamber 121 decreases, and the force received by the discharge valve 92 from the fuel on the pressurizing chamber 121 side is the elastic force of the spring 94 and the force received from the fuel on the downstream side of the second valve seat 95. When the sum is smaller than the sum, the discharge valve 92 is seated on the second valve seat 95. This prevents fuel on the downstream side of the second valve seat 95 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 by the rotation of the camshaft, the volume of the pressurizing chamber 121 increases and the fuel is depressurized. The discharge valve 92 is seated on the valve seat 95 and closes the discharge passage 114. The suction valve 35 moves to the right in FIG. 1 against the urging force of the first spring 21 due to the differential pressure between the pressurizing chamber 121 and the supply passage 100 and is opened. At this time, since energization to the coil 71 is stopped, the movable core 73 and the needle 38 integrated with the movable core 73 move to the right in FIG. 1 by the urging force of the second spring 22. Accordingly, the needle 38 and the suction valve 35 come into contact with each other, and the suction valve 35 maintains the valve open state. As a result, fuel is sucked into the pressurizing chamber 121 from the supply passage 100.

In the suction stroke, the volume of the variable volume chamber 122 decreases due to the lowering of the plunger 13. Therefore, the fuel in the variable volume chamber 122 is sent out to the damper chamber 201 via the cylindrical passage 106, the annular passage 107 and the return passage 108.
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 increase in the volume of the pressurizing chamber 121 to the decrease in the volume of the variable volume chamber 122 is also 1: 0.6. Therefore, 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.

(2) Metering stroke When the plunger 13 rises from the bottom dead center toward the top dead center due to the rotation of the camshaft, the volume of the pressurizing chamber 121 decreases. At this time, since energization to the coil 71 is stopped until a predetermined time, the needle 38 and the suction valve 35 are positioned in the right direction in FIG. 1 by the urging force of the second spring 22. As a result, the supply passage 100 is maintained in an open state. For this reason, the low-pressure fuel once sucked into the pressurizing chamber 121 is returned to the supply passage 100. Therefore, the pressure in the pressurizing chamber 121 does not increase.

In the metering stroke, the volume of the variable volume chamber 122 increases as the plunger 13 moves up. Therefore, the fuel in the damper chamber 201 flows into the variable volume chamber 122 via the return passage 108, the annular passage 107 and the cylindrical passage 106.
At this time, about 60% of the volume of the low-pressure fuel discharged from the pressurizing chamber 121 to the damper chamber 201 is sucked from the damper chamber 201 into the variable volume chamber 122. This reduces about 60% of the fuel pressure pulsation.

(3) Pressurization stroke The coil 71 is energized at a predetermined time while the plunger 13 rises from the bottom dead center toward the top dead center. Then, 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 the magnetic attractive 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 move to the fixed core 72 side (left direction in FIG. 1). As a result, the pressing force of the needle 38 against the suction valve 35 is released. The suction valve 35 moves to the valve seat 34 side by the elastic force of the first spring 21 and the force generated by the flow of low-pressure fuel discharged from the pressurizing chamber 121 to the damper chamber 201 side. Therefore, the suction valve 35 is seated on the valve seat 34 and the supply passage 100 is closed.

From the time when the suction valve 35 is seated on the valve seat, the fuel pressure in the pressurizing chamber 121 becomes higher as the plunger 13 rises toward the top dead center. When the force that the fuel pressure in the pressurizing chamber 121 acts on the discharge valve 92 becomes larger than the force that the fuel pressure in the discharge passage 114 acts on the discharge valve 92 and the urging force of the spring 94, the discharge valve 92 opens. Thereby, the high-pressure fuel pressurized in the pressurizing chamber 121 is discharged from the fuel outlet 91 via the discharge passage 114.
Note that energization of the coil 71 is stopped during the pressurization stroke. Since the force that the fuel pressure in the pressurizing chamber 121 acts on the suction valve 35 is larger than the urging force of the second spring 22, the suction valve 35 maintains the closed state.

The high-pressure pump 10 repeats steps (1) to (3) to pressurize and discharge a necessary amount of fuel to the internal combustion engine.
If the timing of energizing the coil 71 is advanced, the time of the metering stroke is shortened and the time of the pressurizing stroke is lengthened. As a result, the amount of fuel returned from the pressurizing chamber 121 to the supply passage 100 decreases, and the amount of fuel discharged from the discharge passage 114 increases.
On the other hand, if the timing of energizing the coil 71 is delayed, the time of the metering stroke becomes longer and the time of the discharge stroke becomes shorter. Thereby, the fuel returned from the pressurizing chamber 121 to the supply passage 100 increases, and the fuel discharged from the discharge passage 114 decreases.
Thus, by controlling the timing of energizing the coil 71, the amount of fuel discharged from the high-pressure pump 10 can be controlled to an amount required by the internal combustion engine.

The effect of this embodiment is demonstrated.
(1) The relationship between the natural frequency ω (Hz), the spring constant K (N / m), and the mass M (Kg) of the object is expressed by the following Equation 1.
ω∝ (K / M) ^1/2 Formula 1
Further, the relationship among the vibration acceleration G (m / s ² ) of the object, the natural frequency ω (Hz), and the vibration amplitude A (m) is expressed by the following Equation 2.
G∝ω ² × A Equation 2
Combining Equation 1 and Equation 2 yields Equation 3 below.
G∝A × K / M Equation 3
When the vibration amplitude A and the spring constant K of the cover are reduced and the mass M is increased according to Equation 3, the vibration acceleration G is reduced in proportion thereto.
In the present embodiment, the cover 50 is formed such that the thickness t3 of the central portion 52 is thicker than the thickness t1 of the peripheral portion 53. The mass M can be positively increased without increasing the spring constant K of the cover 50 by adjusting the diameter D1 and the wall thickness t3 of the central portion 52 of the cover 50.
Furthermore, in the present embodiment, the thickness t1 of the peripheral portion 53 is formed to be thicker than the thickness t2 of the connection portion 51. As a result, the rigidity of the peripheral portion 53 and the central portion 52 is increased, the vibration amplitude A of the cover 50 is reduced, and the mass M can be increased.
Thereby, the vibration acceleration G of the cover 50 can be reduced. For this reason, the radiated sound emitted from the cover 50 can be reduced by using the opening / closing drive of the suction valve portion 30, the reciprocating motion of the plunger 13 or the fuel pressure pulsation as the vibration source. Therefore, the operation sound of the high-pressure pump 10 due to the radiated sound can be reduced.

(2) In the present embodiment, in the cover 50, the inner wall of the central portion 52 protrudes closer to the damper chamber 201 than the inner wall of the peripheral portion 53. As a result, the mass M of the cover 50 can be increased without causing the cover 50 to protrude toward the outside air. For this reason, the physique of the high-pressure pump 10 can be minimized. Therefore, when the high-pressure pump 10 is mounted on the internal combustion engine, it is possible to prevent the cover 50 of the high-pressure pump 10 and surrounding components from interfering with each other.

(Second Embodiment)
The cover of the high-pressure pump according to the second embodiment of the present invention is shown in FIGS. In the following embodiments, substantially the same components as those in the first embodiment described above are denoted by the same reference numerals and description thereof is omitted. In the present embodiment, the outer wall of the central portion 521 of the cover 501 protrudes in a substantially cylindrical shape on the outside air side from the outer wall of the peripheral portion 53. For this reason, the thickness t4 of the central portion 521 is formed thicker than the thickness t1 of the peripheral portion 53. The diameter D1 and the wall thickness t4 of the central portion 521 are set so as to suppress an increase in the vibration amplitude A and the spring constant K of the cover 501 and positively increase the mass M. Thereby, the vibration acceleration G becomes small and the radiated sound emitted from the cover 50 can be made small.
In the present embodiment, the inner wall of the central portion 521 of the cover 501 does not protrude into the damper chamber 201. For this reason, it becomes possible to enlarge the physique of the pulsation damper 210 provided in the damper chamber 201, or the physique of the first support member 211, the second support member 212, and the wave spring 213 that fix the pulsation damper 210. . Accordingly, the degree of freedom in designing the components in the damper chamber 201 is improved, so that the fuel pressure pulsation damping effect by the damper chamber 201 can be enhanced.

(Third embodiment)
The cover of the high-pressure pump according to the third embodiment of the present invention is shown in FIG. In the present embodiment, the inner wall of the central portion 522 of the cover 502 protrudes closer to the damper chamber 201 than the inner wall of the peripheral portion 53, and the outer wall of the central portion 522 protrudes to the outside air side of the outer wall of the peripheral portion 53. The diameter D1 and the wall thickness t5 of the central portion 521 are set so as to suppress the increase in the vibration amplitude A and the spring constant K of the cover 502 and maximize the mass M. As a result, the natural frequency ω of the cover 502 is reduced, so that the vibration acceleration G can be significantly reduced. Therefore, the radiated sound emitted from the cover 502 can be reduced.

(Fourth embodiment)
The cover of the high-pressure pump according to the fourth embodiment of the present invention is shown in FIG. In the present embodiment, the outer wall of the central portion 523 of the cover 503 protrudes toward the outside air toward the center of the cover 503. For this reason, the central portion 523 of the cover 503 is thicker toward the center of the cover 503.
In the present embodiment, emphasis is placed on increasing the mass of the antinode portion of the vibration of the cover 503. As a result, an increase in the spring constant K of the cover 503 can be suppressed, and the mass M can be increased. Accordingly, since the natural frequency ω of the cover 503 is reduced, the vibration acceleration G can be reduced. Therefore, the radiated sound emitted from the cover 503 can be reduced.
Note that the inner wall of the central portion 523 of the cover 503 may protrude toward the damper chamber 201 toward the center of the cover 503.

(Fifth embodiment)
FIG. 8 shows a cover of the high-pressure pump according to the fifth embodiment of the present invention. In the present embodiment, irregularities are formed in the peripheral portion 533 of the cover 504 by, for example, pressing. The wall thickness t7 of the peripheral portion 533 is substantially the same as the wall thickness t1 of the connection portion 51.
The inner wall of the central part 524 protrudes toward the damper chamber 201 from the inner wall of the peripheral part 534. The thickness t8 of the central portion 524 is thicker than the thickness t7 of the peripheral portion 534. The mass M of the cover 504 can be increased by adjusting the diameter D2 and the wall thickness t8 of the central portion 524.
In the present embodiment, the unevenness is formed in the peripheral portion 534, so that the rigidity is increased and the vibration amplitude A can be reduced. In addition, the mass M can be increased by increasing the thickness t8 of the central portion 524. Thereby, the vibration acceleration G can be made small and the radiated sound emitted from the cover 504 can be made small.

(Sixth to eighth embodiments)
The sixth to eighth embodiments are modifications of the fifth embodiment.
FIG. 9 shows a cover of the high-pressure pump according to the sixth embodiment of the present invention. In the sixth embodiment, the outer wall of the central portion 525 protrudes to the outside air side than the outer wall of the peripheral portion 534.
FIG. 10 shows the cover of the high-pressure pump according to the seventh embodiment of the present invention. In the seventh embodiment, the outer wall of the central portion 526 protrudes to the outside air side from the outer wall of the peripheral portion 534, and the inner wall of the central portion 526 protrudes to the outside air side from the inner wall of the peripheral portion 534.
FIG. 11 shows a cover of the high-pressure pump according to the eighth embodiment of the present invention. In the eighth embodiment, the outer wall of the central portion 527 is formed to increase in thickness toward the center of the cover.
Also in this configuration, the cover mass M can be increased by adjusting the diameter D2 and the wall thickness t8 of the central portions 525, 526, and 527. Therefore, the vibration acceleration G can be reduced and the radiated sound emitted from the cover can be reduced.

(Other embodiments)
In the plurality of embodiments described above, the central portion, the peripheral portion, and the connecting portion are integrally formed. On the other hand, according to the present invention, the central part, the peripheral part, and the connection part may be formed separately and the respective components may be connected.
In the plurality of embodiments described above, the cover is configured by the central portion, the peripheral portion, and the connecting portion, and the connecting portion of the cover and the cylindrical portion of the pump body are connected. On the other hand, in the present invention, the peripheral part of the cover and the cylinder part of the pump body may be directly connected without providing the connection part. Moreover, you may connect a cover directly to the peripheral edge of the recessed part of a pump body, without providing a cylinder part in a pump body.
In the plurality of embodiments described above, the central portion is formed in a cylindrical shape. On the other hand, in the present invention, the shape of the central portion may be any shape such as a prismatic shape or an elliptical shape.
The present invention is not limited to the above embodiment, and can be implemented in various forms without departing from the spirit of the invention.

DESCRIPTION OF SYMBOLS 10 ... High pressure pump 11 ... Pump body 13 ... Plunger 30 ... Intake valve part 50, 501-504 ... Cover 52, 521-527 ... Center part 51 ... Connection part 53 533, 534 ... peripheral portion 90 ... discharge valve portion 100 ... supply passage 114 ... discharge passage 121 ... pressurizing chamber 201 ... damper chamber

Claims (5)

A plunger,
A pump body having a pressurizing chamber in which fuel is pressurized by the reciprocating movement of the plunger;
A suction valve portion for opening or blocking a supply passage through which fuel supplied to the pressurizing chamber flows;
A discharge valve portion for opening or closing a discharge passage through which fuel discharged from the pressurizing chamber flows;
A cover that covers the pump body and is welded to the pump body to cut off fuel in the damper chamber that reduces pressure pulsation of fuel discharged from the pressurizing chamber to the supply passage from outside air. A cover in which the center part of the cover protrudes to the outside air side from the peripheral part,
A pulsation damper provided in the damper chamber for reducing fuel pressure pulsation;
A first support member that supports the pulsation damper from the pump body side of the pulsation damper;
And a second support member that supports the pulsation damper from a side opposite to the pump body of the pulsation damper. The peripheral portion presses the second support member toward the pump body,
The high-pressure pump according to claim 1, wherein the second support member presses the peripheral portion to a side opposite to the pump body. A wave spring provided between the peripheral portion and the second support member;
The peripheral portion presses the second support member toward the pump body via the wave spring,
3. The high-pressure pump according to claim 1, wherein the second support member presses the peripheral portion to the side opposite to the pump body via the wave spring. The cover has a connecting portion that extends in a cylindrical shape from an outer edge of the peripheral portion and has an inner wall connected to the outer wall of the pump body,
The high-pressure pump according to any one of claims 1 to 3, wherein the connection portion is welded from the outside in the radial direction.   The high pressure pump according to any one of claims 1 to 4, wherein fuel can contact the inside of the cover.

Images