JP5517068B2 - High pressure pump - Google Patents

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 supplied from the fuel tank to the high pressure pump is sucked into the pressurizing chamber by the lowering of the plunger provided in the high pressure pump, and is pressurized and fed by the raising of the plunger. Until the middle of the movement of the plunger from the bottom dead center to the top dead center, the electromagnetic drive unit provided in the high-pressure pump opens the suction valve provided in the supply passage for supplying fuel to the pressurizing chamber. Thereby, the pressurizing chamber and the supply passage communicate with each other, and a part of the fuel sucked into the pressurizing chamber is discharged to the supply passage. While the plunger moves from the bottom dead center to the top dead center, the electromagnetic drive unit closes the suction valve. As a result, an appropriate amount of fuel is pressurized and sent from the high-pressure pump to the internal combustion engine.
The electromagnetic drive unit includes a coil, a fixed core, a movable core, a spring, and the like. When the coil is intermittently energized as the plunger reciprocates, the fixed core and the movable core repeat contact and separation at high speed. As a result, pressure fluctuations occur in the fuel in the storage chamber that stores the spring between the fixed core and the movable core. For this reason, when a cavity arises in the fuel of a storage chamber, there exists a possibility that erosion may arise on the inner wall of a storage chamber by collapse of this cavity.
In patent document 1, the erosion is suppressed by performing the mechanical process which raises surface hardness to the end surface which a fixed core and a movable core contact.
In Patent Document 2, a hole (through hole 17 of Cited Document 2) that communicates a receiving chamber and a supply passage of a spring provided in the fixed core and the movable core is provided in the movable core. Thereby, the pressure resistance by the fuel of the storage chamber with respect to the reciprocating movement of the movable core is reduced, and the responsiveness of the movable core is enhanced.

JP 2006-307870 A JP 2010-216360 A

However, since Patent Document 1 increases only the surface hardness of the contact surface between the fixed core and the movable core, there is a possibility that sufficient hardness against stress may not be obtained at other portions where stress due to erosion is large.
In Patent Document 2, it is considered that the pressure fluctuation in the storage chamber is reduced by providing a hole in the movable core that connects the storage chamber and the supply passage. However, if such a hole is provided in the movable core, the damper effect by the fuel in the storage chamber against the reciprocating movement of the movable core cannot be obtained. For this reason, the impact force when a movable core and a fixed core contact | abut increases. Thereby, there exists a possibility that a movable core or a fixed core may be damaged. Moreover, there is a concern about the deterioration of the operating sound due to the collision between the movable core and the fixed core.
This invention is made | formed in view of the said subject, and it aims at providing the high pressure pump which can suppress the erosion of an electromagnetic drive part.

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 electromagnetic drive unit that controls the valve opening or closing operation of the intake valve includes a coil, a fixed core, a movable core, an urging means, and a guide pin.
The fixed core is provided inside the diameter of the coil that generates a magnetic field when energized. The movable core provided on the suction valve side of the fixed core moves the suction valve in the valve opening direction or the valve closing direction. The urging means accommodated in the accommodation chamber provided in at least one of the fixed core and the movable core urges the movable core toward the suction valve. Guide pins of the fixed core by remote high hardness having a receiving chamber, to lock the biasing means in a deep portion of the storage chamber.
When the coil is energized, magnetic flux flows through a magnetic circuit formed by the fixed core and the movable core, and the movable core is magnetically attracted to the fixed core. When the energization of the coil is stopped, the movable core is separated from the fixed core by the urging force of the urging means. As a result, fuel pressure fluctuations occur in the storage chamber that stores the biasing means due to the movement of the movable core, so that a cavity is generated in the fuel in the storage chamber. Guide pins, since it is fixed core by remote high hardness having a housing chamber, in the deep portion of the storage chamber can be suppressed that the erosion caused by the collapse of the cavity.
Further, by providing the guide pin separately from the fixed core and the movable core, the fixed core and the movable core can be formed of a magnetic material having excellent magnetic characteristics. For this reason, the responsiveness of a movable core can be improved.

According to the invention which concerns on Claim 2, a guide pin has a base part which engages with the inner wall of a storage chamber, and latches an urging | biasing means, and a convex part extended from this base part to the opening side of a storage chamber. The convex portion guides the radially inner side of the biasing means, whereby a gap is provided between the radially outer side of the biasing means and the inner wall of the storage chamber.
Erosion tends to occur on the wall surface forming a space with a small volume. For this reason, it is possible to suppress the occurrence of erosion on the inner wall of the storage chamber by providing a gap having a distance capable of suppressing erosion between the outer diameter of the urging means and the inner wall of the storage chamber.
Further, it is possible to suppress sliding contact between the inner wall of the storage chamber and the biasing means.

According to the invention of claim 3, the guide pin includes a locking surface that locks the biasing means on the axial convex side of the base, and a guide surface that guides the radial inside of the biasing means outside the convex part. And a tapered surface provided closer to the opening side of the storage chamber than the guide surface of the convex portion.
As a result, the guide surface is guided by the end portion on the base side of the urging means, and the portion where the urging means expands and contracts is reduced in a taper shape, so that both slide in contact with each other to inhibit the expansion and contraction in the axial direction. Without restricting the radial movement of the urging means. Thereby, the expansion / contraction function of the urging means can be maintained, and a gap can be provided between the radially outer side of the urging means and the inner wall of the storage chamber.
Further, the urging means can be easily assembled to the guide pin by inserting the inner diameter side of the urging means into the convex portion along the tapered surface.

According to the invention which concerns on Claim 4, the convex part of a guide pin is dented in an annular | circular shape to an inner radial direction between a locking surface and a guide surface, and the terminal internal-diameter corner | angular part of an urging | biasing means is to the corner R of a convex root. It has an annular recess that can be avoided.
Thereby, since the uprightness of the urging means in the axial direction is maintained, the gap between the radially outer side of the urging means and the inner wall of the storage chamber can be maintained. Further, since the sliding contact between the two can be avoided, the set load characteristic of the urging means can be maintained.

According to the fifth aspect of the present invention, the guide pin is provided with the locking side surface chamfered portion outside the diameter of the locking surface of the base portion. The distance in the axial direction of the locking side chamfer is small enough to suppress erosion of the inner wall of the storage chamber located in the radially outward direction of the locking side chamfer.
By reducing the axial distance of the locking side surface taking portion, the volume of the substantially wedge-shaped space formed between the locking side surface taking portion and the inner wall of the storage chamber is reduced. For this reason, it can suppress that erosion arises in the inner wall of the storage chamber located in the radial direction of a latching side surface taking part.

According to the sixth aspect of the present invention, the guide pin is provided with the bottom side surface chamfered portion on the outer diameter side of the bottom surface opposite to the convex portion of the base portion. The angle formed by the bottom side chamfered portion and the bottom surface of the base is large enough to suppress wear of the bottom wall of the storage chamber due to the contact end.
Thereby, the fretting wear of the bottom wall of the storage chamber by the base is suppressed, and the posture of the guide pin is maintained. For this reason, since the uprightness of the urging means in the axial direction is maintained, a gap between the radially outer side of the urging means and the inner wall of the storage chamber can be maintained. Moreover, the set load of the urging means can be maintained.
In addition, when the guide pin is inserted into the storage chamber, the bottom side chamfer smoothly moves through the step between the large diameter hole and the small diameter hole of the storage chamber, so that the guide pin can be easily assembled to the small diameter hole.

According to the invention which concerns on Claim 7, the accommodation chamber which a fixed core or a movable core has has a small diameter hole into which the base part of a guide pin fits, and a large diameter with an internal diameter larger than a small diameter hole by the opening side of an accommodation chamber from this small diameter hole And a hole.
Thereby, the clearance gap provided between the inner wall of the large diameter hole which forms a storage chamber, and an urging | biasing means can be enlarged, and it can suppress that erosion arises in the inner wall of a large diameter hole. Further, it is possible to suppress the urging means from slidingly contacting the inner wall of the large diameter hole.
Furthermore, when the guide pin is inserted into the storage chamber, the base portion of the guide pin easily passes through the large diameter hole, so that the guide pin can be easily assembled into the small diameter hole.

According to the invention which concerns on Claim 8, the storage chamber which a fixed core or a movable core has has a level | step difference between a small diameter hole and a large diameter hole. The step is located closer to the opening side of the storage chamber than the locking surface of the guide pin.
Thus, the inner wall of the small-diameter hole and the outer wall of the base can be brought into contact with each other without expanding a minute substantially wedge-shaped space between the inner wall of the large-diameter hole and the outer wall of the base in the radial direction. Therefore, it is possible to suppress the occurrence of erosion on the inner wall of the storage chamber.

According to the invention which concerns on Claim 9, shot peening is given to the inner wall of a storage chamber.
Thereby, while maintaining the magnetic characteristic of the fixed core which has a storage chamber, or a movable core, it can suppress that erosion arises in the inner wall of a storage chamber by raising surface hardness.

According to the tenth aspect of the present invention, the guide pin is press-fitted into the inner wall of the storage chamber.
Thereby, the clearance gap between the outer wall of a base and the inner wall of a storage chamber becomes substantially zero. Therefore, it is possible to suppress the occurrence of erosion on the inner wall of the storage chamber located outside the diameter of the base.

According to the eleventh aspect of the present invention, the base of the guide pin is loosely fitted to the inner wall of the storage chamber.
Thereby, the guide pin fitting part of a fixed core or a movable core can be easily formed in a predetermined inner diameter tolerance range. Further, the guide pin can be easily formed within a predetermined outer diameter tolerance range.

According to the twelfth aspect of the present invention, the guide pin is harder than the biasing means.
Thereby, it becomes possible to suppress fretting wear of the locking surface of the guide pin. For this reason, since the uprightness of the urging means in the axial direction is maintained, a gap between the radially outer side of the urging means and the inner wall of the storage chamber can be maintained. Moreover, the set load of the urging means can be maintained.

In the invention which concerns on Claim 13, it is possible to grasp the electromagnetic drive part of a high-pressure pump as an electromagnetic drive device. Thereby, there can exist the same effect as the invention concerning Claim 1 mentioned above.
Note that the inventions according to claims 2 to 12 may be applied to the invention according to claim 13.

It is sectional drawing of the high pressure pump by 1st Embodiment of this invention. It is sectional drawing of the electromagnetic drive part of the high pressure pump by 1st Embodiment of this invention. It is a principal part enlarged view of the guide pin mounting part of FIG. It is a characteristic view of the member which comprises the electromagnetic drive part of the high pressure pump by 1st Embodiment of this invention. It is sectional drawing of the electromagnetic drive part of the high pressure pump by 2nd Embodiment of this invention. FIG. 6 is a sectional view taken along line VI-VI in FIG. 5. It is sectional drawing of the electromagnetic drive part of the high pressure pump by 3rd Embodiment of this invention. It is the VIII-VIII sectional view taken on the line of FIG. It is a principal part enlarged view of the guide pin mounting part of the high pressure pump by 4th Embodiment of this invention. It is a principal part enlarged view of the guide pin mounting part of the high pressure pump by a comparative example.

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 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.
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 with reference to FIGS.
The electromagnetic drive unit 70 includes a flange 75, a coil 71, a fixed core 72, a movable core 73, a second spring 22 as urging means, a guide pin 80, and the like.
The fixed core 72, the movable core 73, and the flange 75 are formed by magnetic annealing of a magnetic material such as ferritic stainless steel, and constitute a magnetic circuit through which a magnetic flux excited by the coil 71 flows.

The flange 75 is attached to the cylindrical portion 15 of the pump body 11 and closes the end of the cylindrical portion 15. A cylindrical movable core chamber 74 that houses the movable core 73 is provided on the opposite side of the flange 75 from the cylindrical portion 15.
The movable core 73 is accommodated in the movable core chamber 74 so as to be reciprocally movable in the axial direction. The movable core 73 has a plurality of breathing holes 731 communicating in the axial direction. The fuel flows through one side and the other side of the movable core 73 in the movable core chamber 74 through the breathing hole 731.
A cylindrical guide cylinder 76 is fixed to the inner wall of the hole provided in the center of the flange 75. A needle 38 is provided inside the guide cylinder 76 so as to be reciprocally movable. 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. The fuel flows into the movable core chamber 74 from the supply passage 100 via a notch 39 provided on the outer wall in the radially outward direction of the needle 38.

A connector 77 is held on the side of the flange 75 opposite to the cylindrical portion by the yoke 12 constituting the magnetic circuit. A coil 71 is wound around a bobbin 78 provided inside the connector 77. When the coil 71 is energized through the terminal 771 of the connector 77, the coil 71 generates a magnetic field.
The fixed core 72 is disposed on the inner side of the bobbin 78 so as to face the movable core 73. A cylindrical member 79 made of a nonmagnetic material is provided between the flange 75 and the fixed core 72. The cylindrical member 79 is inserted into a magnetic blocking portion between the fixed core 72 and the flange 75 for passing a magnetic flux through an air gap for generating an attractive force between the fixed core 72 and the movable core 73, and is blocked from the outside. The movable core chamber 74 is configured.

The fixed core 72 has a first storage chamber 61 that opens at an end portion on the movable core 73 side. In addition, the movable core 73 has a second storage chamber 62 that opens at an end portion on the fixed core 72 side. The inner wall of the first storage chamber 61 of the fixed core 72 is shot peened to increase the surface hardness. The inner wall of the second storage chamber 62 of the movable core 73 is hard-plated to increase the surface hardness.
The second spring 22 is accommodated in the first accommodation chamber 61 of the fixed core 72 and the second accommodation chamber 62 of 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.
The first storage chamber 61 of the fixed core 72 is formed by a small-diameter hole 63 in the deep portion of the first storage chamber 61 and a large-diameter hole 64 having an inner diameter larger than that of the small-diameter hole 63 on the opening side of the storage chamber. Yes.

A guide pin 80 for locking the second spring 22 is provided in the first storage chamber 61. The guide pin 80 is formed with higher hardness than the fixed core 72, the movable core 73, and the second spring 22 by, for example, quenching martensitic stainless steel. The guide pin 80 has a Vickers hardness of Hv400 or higher. Preferably, it is Hv650 or more. The guide pin 80 includes a base portion 81, a convex portion 82, a locking surface 83, a guide surface 84, a tapered surface 85, and the like.
The base 81 is fitted to the inner wall of the small diameter hole 63 of the first storage chamber 61 by loose fit. A locking surface 83 formed on the axially protruding portion side of the base 81 is formed perpendicular to the axis of the guide pin 80 and locks the second spring 22.

The convex portion 82 extends from the base portion 81 to the opening side of the first storage chamber 61. A guide surface 84 that guides the radially inner side of the second spring 22 is formed on the radially outer side of the convex portion 82. The guide surface 84 guides one turn (about 270 to 360 °) of the spring wire from the tip of the second spring 22.
A tapered surface 85 is provided on the opposite side of the base 81 from the guide surface 84 of the convex portion 82. The tapered surface 85 limits the movement of the second spring 22 in the radial direction without hindering the expansion and contraction of the second spring 22 in the axial direction. Further, since the tapered surface 85 guides the second spring 22, the second spring 22 can be easily inserted into the convex portion 82.
The locking surface 83 of the base portion 81 locks the second spring 22, and the guide surface 84 of the convex portion 82 guides the radially inner side of the second spring 22, so that the inner wall of the large-diameter hole 64, the second spring 22, A gap is provided between the two. By increasing this gap, it is possible to suppress the occurrence of erosion on the inner wall of the large-diameter hole 64. In addition, sliding contact between the inner wall of the large diameter hole 64 and the second spring 22 can be suppressed.

A bottom side chamfer 87 is provided on the outer side of the bottom surface 86 opposite to the convex portion 82 of the base 81. It is preferable that the angle formed by the bottom side chamfer 87 and the bottom surface 86 is formed large. In the present embodiment, the bottom surface 86 side of the bottom side chamfer 87 is formed as a curved surface. Thereby, the deformation or fretting wear of the bottom wall of the first storage chamber 61 due to the surface pressure of the base 81 is suppressed.
A locking side chamfer 88 is provided on the outer side of the locking surface 83 of the base 81. The distance h in the axial direction of the locking side chamfer 88 is preferably small. Thereby, since the volume of the substantially wedge-shaped space formed between the locking side surface taking part 88 and the inner wall of the first storage chamber 61 is reduced, it is possible to suppress the occurrence of erosion on the inner wall of the first storage chamber 61. be able to.
The convex portion 82 has an annular concave portion 89 that is annularly recessed in the radial direction between the base portion 81 and the guide surface 84. The connection part of the convex part 82 and the base part 81 is formed in a curved surface shape by cutting. The annular concave portion 89 prevents the end inner diameter corner portion of the second spring 22 from climbing onto R, which can be processed at the root corner of the convex portion 82. Thereby, the uprightness of the 2nd spring 22 is maintained.

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.
When the coil 71 is energized, a magnetic flux flows through a magnetic circuit formed by the fixed core 72, the movable core 73, the flange 75, and the yoke 12, and the movable core 73 resists the elastic force of the second spring 22. Magnetically attracted to the side. As a result, the needle 38 releases the pressing force on the suction valve 35.

Next, the variable volume chamber 122 will be described with reference to FIG.
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, and the later-described discharge valve 92 is changed by changing the spring load depending on the installation position of the regulating member 93. The valve opening pressure can be adjusted.

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 spring 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 spring 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.

Next, FIG. 4 shows a test result of the erosion suppressing effect on the fixed core 72, the second spring 22, and the guide pin 80 constituting the electromagnetic drive unit 70. As shown in FIG. In this test, each member was placed in a container containing fuel, and a cavity was generated in the fuel by a magnetostrictive vibrator, whereby each member was repeatedly stressed.
For the fixed core not subjected to shot peening, the fixed core 72 subjected to shot peening, the second spring 22 and the guide pin 80, five members having the same configuration were prepared. For each member, stress was repeatedly applied at five levels of stress due to cavitation, and the number of times that damage was confirmed on the surface of each member was plotted.

The solid line A shows the test result of the fixed core not subjected to shot blasting. The solid line B shows the test result of the fixed core 72 subjected to shot peening. A test result of the second spring 22 is shown by a solid line C. These members were confirmed to start damage in a small number of times when the stress due to cavitation was increased. In addition, when the stress due to cavitation was reduced, the onset of damage was confirmed many times. In the fixed core 72 subjected to shot peening, when the stress due to cavitation was the lowest, as shown in D, no damage was confirmed at about 2.8 × 10 ⁸ times.
When the stress due to cavitation was at the same level, the number of damage initiations increased in the order of the fixed core not subjected to shot peening, the fixed core 72 subjected to shot peening, and the second spring 22.
Further, as shown by E, the guide pin 80 obtained by quenching martensitic stainless steel was not damaged at about 2.8 × 10 ⁸ times even when the stress due to cavitation was highest. As a result, it was confirmed that the guide pin 80 of this embodiment has a very low possibility of causing erosion.

This embodiment has the following effects.
(1) Due to the reciprocating movement of the movable core 73, the fuel pressure in the first storage chamber 61 and the second storage chamber 62 decreases when the movable core 73 is separated, and a cavity is generated in the fuel. Next, when seated, the fuel pressure rises, the cavity collapses, and erosion may occur particularly in the deep portion of the first storage chamber 61. Since the guide pin 80 of the present embodiment has a higher hardness than the fixed core 72 having the first storage chamber 61, it is possible to suppress erosion from occurring in the deep portion of the first storage chamber 61 due to the collapse of the cavity.
Further, by providing the guide pin 80 separately from the fixed core 72 and the movable core 73, the fixed core 72 and the movable core 73 can be formed of a magnetic material having excellent magnetic characteristics. For this reason, the responsiveness of the movable core 73 can be improved.
Furthermore, the damper effect when the movable core 73 and the fixed core 72 collide is maintained by the fuel pressure in the first storage chamber 61 and the second storage chamber 62. Therefore, it is possible to achieve both suppression of erosion and relaxation of impact force when the movable core 73 and the fixed core 72 abut.

(2) Since the guide surface 84 of the guide pin 80 guides the inner side of the second spring 22, a gap is provided between the outer side of the second spring 22 and the inner wall of the large-diameter hole 64. Due to this gap, it is possible to suppress the occurrence of erosion on the inner wall of the large-diameter hole 64. In addition, the second spring 22 can be prevented from slidingly contacting the inner wall of the large diameter hole 64.
Further, when the guide pin 80 is inserted into the first accommodation chamber 61, the base portion 81 of the guide pin 80 easily passes through the large diameter hole 64, so that the guide pin 80 can be easily assembled to the inner wall of the small diameter hole 63. .

(3) The tapered surface 85 provided on the convex portion 82 of the guide pin 80 restricts the movement of the second spring 22 in the radial direction without inhibiting the expansion and contraction of the second spring 22 in the axial direction. Therefore, the expansion / contraction function of the second spring 22 can be maintained, and a gap can be provided between the radially outer side of the second spring 22 and the inner wall of the large-diameter hole 64.
Further, the second spring 22 can be easily assembled to the guide pin 80 by inserting the radially inner side of the second spring 22 into the convex portion 82 along the tapered surface 85.

(4) The annular concave portion 89 provided in the convex portion 82 of the guide pin 80 prevents the second spring 22 end corner portion from climbing up to the corner R that can be formed when the convex portion 82 is processed. For this reason, since the uprightness of the second spring 22 in the axial direction is maintained, a gap between the radially outer side of the second spring 22 and the inner wall of the large-diameter hole 64 can be maintained. Further, the set load of the second spring 22 can be maintained.

(5) By increasing the angle formed by the bottom side chamfer 87 provided on the base 81 of the guide pin 80 and the bottom 86 of the base 81, fretting wear on the bottom wall of the first storage chamber 61 is suppressed, and the guide The posture of the pin 80 is maintained. For this reason, since the uprightness of the second spring 22 in the axial direction is maintained, a gap between the radially outer side of the second spring 22 and the inner wall of the large-diameter hole 64 can be maintained. Further, the set load of the second spring 22 can be maintained.
Further, when the guide pin 80 is inserted into the storage chamber, the bottom side chamfer 87 smoothly moves along the step between the large diameter hole 64 and the small diameter hole 63 of the first storage chamber 61, so that the guide pin 80 is changed to the small diameter hole 63. Can be assembled easily.

(6) By increasing the surface hardness while maintaining the magnetic properties of the fixed core 72 or the movable core 73 by performing shot peening on the inner wall of the first storage chamber 61 and the inner wall of the second storage chamber 62, It is possible to prevent erosion from occurring on the inner wall of the first storage chamber 61 and the inner wall of the second storage chamber 62.

(7) In the guide pin 80, the base 81 is loosely fitted to the inner wall of the small diameter hole 63, so that the small diameter hole 63 can be easily formed in the fixed core 72 within a predetermined inner diameter tolerance range. Further, the guide pin 80 can be easily formed within a predetermined outer diameter tolerance range.
(8) Since the guide pin 80 is harder than the second spring 22, it is possible to suppress fretting wear of the locking surface 83 of the guide pin 80. For this reason, since the uprightness of the second spring 22 in the axial direction is maintained, a gap between the radially outer side of the second spring 22 and the inner wall of the large-diameter hole 64 can be maintained. Further, the set load of the second spring 22 can be maintained.

Here, in order to explain further functions and effects of the present embodiment, the relationship between the first storage chamber and the guide pin of the fuel pump according to the comparative example is shown in FIG. In FIG. 10, the configuration corresponding to the first embodiment is denoted by “0” at the end of the reference numeral, and description thereof is omitted.
In the comparative example, the step 650 between the small-diameter hole 630 and the large-diameter hole 640 of the first storage chamber 610 is positioned outside the diameter of the base 810. For this reason, an annular minute space 660 is formed between the base 810 and the large-diameter hole 640. Here, erosion tends to occur in the deep portion of the first storage chamber 610 and the small space 660 having a small volume due to pressure propagation. For this reason, in the comparative example, erosion may occur on the inner wall of the large-diameter hole 640 located on the outer diameter side of the base 810.

On the other hand, this embodiment has the following effects.
(9) The step between the small diameter hole 63 and the large diameter hole 64 of the first storage chamber 61 is located on the opening side of the locking surface 83 of the guide pin 80. Thereby, the inner wall of the small-diameter hole 63 and the outer wall of the base 81 are brought into contact with each other without forming a minute space between the inner wall of the large-diameter hole 64 and the outer wall of the base 81 in the radial direction. Therefore, it is possible to suppress the occurrence of erosion on the inner wall of the first storage chamber 61.
Further, in the present embodiment, the axial distance h of the locking side chamfer 88 of the guide pin 80 is reduced to reduce the space formed between the locking side chamfer 88 and the inner wall of the small diameter hole 63. The volume becomes smaller. For this reason, it can suppress that erosion arises in the inner wall of the small diameter hole 63 located in the radial outward direction of the latching side surface taking part 88. FIG.

(Second Embodiment)
An electromagnetic drive unit 70 of a fuel pump according to a second embodiment of the present invention is shown in FIGS. Hereinafter, in the plurality of 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 base 81 of the guide pin 80 is press-fitted into the inner wall of the small diameter hole 63 of the first storage chamber 61. The guide pin 80 is provided with a hole 801 communicating in the axial direction. Thereby, the air of the deep part of the 1st storage chamber 61 can be extracted at the time of the press injection of the guide pin 80. Therefore, the guide pin 80 can be reliably press-fitted into the inner wall of the small diameter hole 63.
In the present embodiment, in addition to the operational effects of the first embodiment described above, the gap between the outer wall of the base 81 of the guide pin 80 and the inner wall of the small diameter hole 63 can be made substantially zero. Therefore, it is possible to reliably suppress the occurrence of erosion on the inner wall of the small diameter hole 63 positioned on the outer diameter side of the base portion 81.

(Third embodiment)
7 and 8 show an electromagnetic drive unit 70 of a fuel pump according to a third embodiment of the present invention. In the present embodiment, the base 81 of the guide pin 80 is press-fitted into the inner wall of the small diameter hole 63 of the first storage chamber 61. The guide pin 80 is provided with a planar notch 802 on the outer wall in the radially outward direction. Due to the passage 67 formed between the notch 802 and the inner wall of the small diameter hole 63, the air in the deep part of the first storage chamber 61 can be extracted during press-fitting. Therefore, the guide pin 80 can be reliably press-fitted into the small diameter hole 63.
In the present embodiment, the same operational effects as those of the first and second embodiments described above can be achieved.

(Fourth embodiment)
FIG. 9 shows an enlarged view of the main part of the electromagnetic drive unit 70 of the fuel pump according to the fourth embodiment of the present invention. In the present embodiment, the inner diameter of the first accommodating chamber 61 of the fixed core 72 is formed substantially the same from the opening side to the deep part, and the large diameter hole 64 and the small diameter hole 63 are not provided.
Here, erosion may occur at corners such as steps. In the present embodiment, since no step is formed in the first storage chamber 61, it is possible to further suppress the occurrence of erosion on the inner wall of the first storage chamber 61.

(Other embodiments)
In the above-described embodiment, the normally open valve in which the movable core 73 opens the intake valve 35 when the coil 71 is not energized has been described. On the other hand, the present invention may be applied to a normally closed valve in which the movable core closes the suction valve when the coil is not energized.
In the embodiment described above, the guide pin 80 is provided in the first storage chamber 61 of the fixed core 72. On the other hand, according to the present invention, a guide pin may be provided in the second storage chamber of the movable core.
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 22 ... 2nd spring (biasing means)
35 ・ ・ ・ Suction valve 61 ・ ・ ・ First storage chamber (storage chamber)
62 ... 2nd accommodation room (accommodation room)
63 ... small diameter hole 64 ... large diameter hole 65 ... step 70 ... electromagnetic drive unit 71 ... coil 72 ... fixed core 73 ... movable core 80 ... guide pin 81 .... Base part 82 ... Protruding part 83 ... Locking surface 84 ... Guide surface 85 ... Tapered surface 87 ... Bottom side chamfering part 88 ... Locking side chamfering part 89 ... Ring Recess 92 ... Discharge valve 100 ... Supply passage 114 ... Discharge passage 121 ... Pressure chamber

Claims (13)

A plunger,
A pump body having a pressurizing chamber in which fuel is pressurized by the reciprocating movement of the plunger;
A suction valve for opening or closing a supply passage through which fuel supplied to the pressurizing chamber flows;
A discharge valve for opening or closing a discharge passage through which fuel discharged from the pressurizing chamber flows;
An electromagnetic drive unit that controls a valve opening operation or a valve closing operation of the suction valve,
The electromagnetic drive unit is
A coil that generates a magnetic field when energized,
A fixed core provided inside the diameter of the coil;
A movable core that is provided on the suction valve side of the fixed core and moves the suction valve in a valve opening direction or a valve closing direction;
A biasing means that is accommodated in a storage chamber provided in at least one of the fixed core and the movable core, and biases the movable core toward the suction valve;
The stator is A by remote high hardness, high-pressure pump characterized by having a guide pin for engaging said biasing means in a deep portion of the accommodating chamber with the housing chamber. The guide pin has a base portion that fits the inner wall of the storage chamber and locks the urging means, and a convex portion that extends from the base portion to the opening side of the storage chamber,
2. The high pressure according to claim 1, wherein a gap is provided between a radially outer side of the biasing means and an inner wall of the storage chamber by the convex portion guiding the radially inner side of the biasing means. pump. The guide pin is
A locking surface for locking the biasing means on the axially convex side of the base,
A guide surface that guides the radially inner side of the urging means on the radially outer side of the convex part;
The high-pressure pump according to claim 2, further comprising a tapered surface provided closer to the opening side of the housing chamber than the guide surface of the convex portion.   The convex portion of the guide pin is annularly recessed in the radially inward direction between the base portion and the guide surface, and an annular shape capable of avoiding climbing of the urging means terminal inner corner to the convex root corner R. The high pressure pump according to claim 3, further comprising a recess. The guide pin is provided with a locking side chamfered portion on the outer diameter side of the locking surface of the base,
5. The axial distance of the locking side chamfered portion is small enough to suppress erosion of the inner wall of the storage chamber located in the radially outward direction of the locking side chamfered portion. The high-pressure pump described in 1. The guide pin is provided with a bottom side chamfer on the outer diameter side of the bottom surface opposite to the convex portion of the base,
The corner portion formed by the bottom side chamfered portion and the bottom surface of the base portion has a large angle or an R shape that can suppress local wear of the bottom wall of the storage chamber due to the surface pressure of the base portion. The high pressure pump according to any one of claims 3 to 5.   The storage chamber of the fixed core or the movable core includes a small-diameter hole into which the base portion of the guide pin is fitted, and a large-diameter hole having an inner diameter larger than the small-diameter hole on the opening side of the storage chamber from the small-diameter hole The high-pressure pump according to claim 3, wherein the high-pressure pump is formed by: The storage chamber of the fixed core or the movable core has a step between the small diameter hole and the large diameter hole,
The high-pressure pump according to claim 7, wherein the step is located closer to the opening side of the storage chamber than the locking surface of the guide pin.   The high pressure pump according to any one of claims 1 to 8, wherein shot peening is performed on an inner wall of the storage chamber of the fixed core or the movable core. The high-pressure pump according to any one of claims 2 to 5 , wherein the base of the guide pin is press-fitted into an inner wall of the storage chamber.   10. The high-pressure pump according to claim 2, wherein the base of the guide pin is loosely fitted to an inner wall of the storage chamber.   The high-pressure pump according to any one of claims 1 to 11, wherein the guide pin has higher hardness than the urging means. In an electromagnetic drive device for controlling a valve opening operation or a valve closing operation of an intake valve for intermittently flowing a fuel flow sucked or discharged into a pressurizing chamber in which fuel is pressurized by a reciprocating movement of a plunger provided in a high pressure pump,
A coil that generates a magnetic field when energized,
A fixed core provided inside the diameter of the coil;
A movable core that is provided on the suction valve side of the fixed core and moves the suction valve in a valve opening direction or a valve closing direction;
A biasing means that is accommodated in a storage chamber provided in at least one of the fixed core and the movable core, and biases the movable core toward the suction valve;
Provided deep in the said receiving chamber, it engages the biasing means, a and the fixed core by remote high hardness with the accommodating chamber, for locking said biasing means in a deep portion of the accommodating chamber An electromagnetic drive device comprising a guide pin.

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