WO2019207906A1

WO2019207906A1 - High-pressure fuel supply pump

Info

Publication number: WO2019207906A1
Application number: PCT/JP2019/004957
Authority: WO
Inventors: 将通谷貝; 前田　直宏; 徳尾　健一郎; 小野瀬　亨; 新鍵山
Original assignee: 日立オートモティブシステムズ株式会社
Priority date: 2018-04-26
Filing date: 2019-02-13
Publication date: 2019-10-31
Also published as: JPWO2019207906A1; CN111989478A; DE112019001337T5; JP6938776B2; CN111989478B

Abstract

Provided is a high-pressure fuel pump configured so that wear caused by the relative rotation between a movable core and a rod can be suppressed. This high-pressure fuel pump is provided with a valve body 30, a rod 35, a stationary core 39, a movable core 36, a rod-biasing spring 40 (first spring), and an anchor-biasing spring 41 (second spring). The rod 35 drives the valve body 30. The stationary core 39 generates a magnetic force. The movable core 36 is configured as a separate body from the rod 35 and is attracted by the stationary core 39 to drive the rod 35. The rod-biasing spring 40 biases the rod 35 toward the valve body 30. The anchor-biasing spring 41 biases the movable core 36 in the direction opposite the direction of biasing by the rod-biasing spring 40. In a state in which the movable core 36 is in contact with the stationary core 39, the load of the anchor-biasing spring 41 is 10% or more of the load of the rod-biasing spring 40.

Description

High pressure fuel supply pump

The present invention relates to a high-pressure fuel supply pump.

2. Description of the Related Art Among direct-injection internal combustion engines that directly inject into a combustion chamber among automobile internal combustion engines, high-pressure fuel pumps equipped with electromagnetic suction valves that increase the pressure of fuel and discharge a desired fuel flow rate are widely used. .

Patent Document 1 states that “a high-pressure fuel supply including an electromagnetic suction valve that adjusts the amount of fuel sucked into a pressurizing chamber, a discharge valve that discharges fuel from the pressurizing chamber, and a plunger that can reciprocate in the pressurizing chamber. The electromagnetic suction valve is a pump, and has an electromagnetic coil, a suction valve, and a movable part capable of operating the suction valve in a closing direction by a magnetic suction force when the electromagnetic coil is energized. It consists of an anchor part that drives the suction valve in the closing direction by force and collides with the fixed member to stop the movement, and a rod part that is driven in conjunction with the anchor part and can continue to move even after the anchor part stops moving. The electromagnetic intake valve has a first spring that urges the intake valve in the closing direction, a second spring that urges the intake valve in the opening direction via the rod portion, and a force that presses the rod portion against the anchor portion. With a third spring applied to the part. " It has been mounting.

According to the invention described in Patent Document 1, after the electromagnetic force is released and the rod moves to the suction valve side by the rod biasing spring and stops colliding with the suction valve, the anchor tries to continue to move with the inertial force. The anchor biasing spring according to the present invention allows the anchor to be positioned at a predetermined position, so that the anchor does not collide with another member to generate noise and is positioned at a position where suction is possible. The flow rate can be controlled.

International Publication No. 2016/031378

However, in the high-pressure fuel pump described in Patent Document 1, the separated anchor (movable core) and the rod are urged so as to be pressed against each other by two springs. In general, a coil spring generates a rotational force on both end faces as it is compressed and expanded.
This rotational force causes relative rotation on the contact surface between the movable core and the rod, and there is a problem that wear occurs on the contact surface.

An object of the present invention is to provide a high-pressure fuel pump that can suppress wear due to relative rotation between a movable core and a rod.

In order to achieve the above object, the present invention comprises a valve body, a rod that drives the valve body, a fixed core that generates magnetic force, and a rod and a separate body, and is attracted to the fixed core. The movable core that drives the rod, a first spring that biases the rod toward the valve body, and the movable core that biases the movable core in a direction opposite to the biasing direction of the first spring. A second spring, wherein the load of the second spring is 10% or more of the load of the first spring when the movable core is in contact with the fixed core.

According to the present invention, wear due to relative rotation between the movable core and the rod can be suppressed. Problems, configurations, and effects other than those described above will be clarified by the following description of embodiments.

It is a longitudinal cross-sectional view of the high pressure fuel pump of this invention. It is the horizontal direction sectional view seen from the upper direction of the high-pressure fuel pump of the present invention. It is an expanded longitudinal cross-sectional view of the electromagnetic suction valve of the high-pressure fuel pump of the present invention. It is sectional drawing which shows the relationship between the maximum line length of an anchor biasing spring used for the high-pressure fuel pump of this invention, and a wire diameter. It is sectional drawing which shows the relationship between the straight line which connects the wire diameter center of the anchor biasing spring used for the high-pressure fuel pump of this invention, and the centerline of a flow-path hole. It is a perspective view of the movable core used for the high-pressure fuel pump of the present invention. The block diagram of the engine system to which the high pressure fuel pump of this invention was applied is shown.

Hereinafter, embodiments of the high-pressure fuel pump of the present invention will be described in detail with reference to the drawings. In the drawings, the same reference numerals denote the same parts.

(overall structure)
First, the configuration and operation of the system will be described with reference to the overall configuration diagram of the engine system shown in FIG. A portion surrounded by a broken line indicates a main body of the high-pressure fuel pump 1 (hereinafter referred to as a high-pressure pump), and indicates that the mechanisms and parts shown in the broken line are integrated into the pump body 1A. .

The fuel in the fuel tank 101 is pumped up by the feed pump 103 based on a signal from the ECU 102 (Engine Control Unit). This fuel is pressurized to an appropriate feed pressure and sent to the low pressure fuel inlet 2A of the high pressure pump through the suction pipe 104. The fuel that has passed through the suction joint 17 (FIG. 2) from the low-pressure fuel suction port 2A reaches the suction port 31B of the electromagnetic suction valve 300 constituting the variable capacity mechanism via the pressure pulsation reducing mechanism 3 and the suction passage 2B.

The fuel that has flowed into the electromagnetic suction valve 300 passes through the fuel introduction passage 30P and the valve body 30, and flows into the pressurizing chamber 4. Power for reciprocating motion is applied to the plunger 5 by an engine cam 105 (cam mechanism). Due to the reciprocating motion of the plunger 5, fuel is sucked from the valve body 30 during the downward stroke of the plunger 5, and the fuel is pressurized during the upward stroke. When the fuel is pressurized, the fuel is pumped through the discharge valve mechanism 500 (FIG. 2) to the common rail 108 to which the pressure sensor 107 is attached.

Then, based on a signal from the ECU 102, the injector 110 injects fuel into the combustion chamber. Although the present embodiment describes a high-pressure pump applied to a so-called direct injection engine system in which the injector 110 blows fuel directly into the cylinder cylinder of the engine, it can also be applied to other systems. Upon receiving a signal from the ECU 102 to the electromagnetic suction valve 300, the high pressure pump discharges a desired fuel flow rate toward the common rail.

(High pressure pump structure)
Hereinafter, the detailed structure of the high-pressure pump will be described with reference to FIGS. FIG. 1 is a longitudinal sectional view of the high-pressure pump of this embodiment, and FIG. 2 is a horizontal sectional view of the high-pressure pump as viewed from above.

First, the present embodiment will be described with reference to FIG. The high-pressure pump of this embodiment is in close contact with the plane of the cylinder head 112 of the internal combustion engine using a mounting flange 1B provided on the pump body 1A, and is fixed with a plurality of bolts (not shown).

In order to seal between the cylinder head 112 and the pump body 1A, an O-ring 7 is fitted in the pump body 1A. This prevents engine oil from leaking outside.

A cylinder 6 for guiding the reciprocating motion of the plunger 5 is attached to the pump body 1A. Further, the pump body 1A is provided with an electromagnetic suction valve 300 for supplying fuel to the pressurizing chamber 4, and a discharge valve mechanism 500 for discharging fuel from the pressurizing chamber 4 to the discharge passage to prevent backflow. ing. The fuel that has passed through the discharge valve mechanism 500 moves to engine-side parts such as a common rail through the discharge joint 18.

The cylinder 6 is fixed to the pump body 1A by press-fitting on the outer peripheral side thereof, and the fuel is sealed at the surface of the cylindrical press-fitting portion so that the pressurized fuel from the gap with the pump body 1A does not leak to the low-pressure side. By bringing the cylinder 6 into a plane contact in the axial direction, it is possible to double seal in addition to the cylindrical press-fit portion between the pump body 1A and the cylinder 6.

The cam 105 attached to the cam shaft of the internal combustion engine is disposed at the lower end of the plunger 5. Further, a tappet 10 that converts the rotational motion of the cam 105 into a vertical motion and transmits the motion to the plunger 5 is provided. The plunger 5 is crimped to the tappet 10 by a spring 12 via a retainer 15. With this configuration, the plunger 5 can be reciprocated up and down as the cam 105 rotates.

A plunger seal 14 held at the lower end of the inner periphery of the seal holder 13 is installed so as to slidably contact the outer periphery of the plunger 5 at the lower part of the cylinder 6 in the figure.
As a result, when the plunger 5 slides, the fuel in the sub chamber 13A is sealed and prevented from flowing into the internal combustion engine. At the same time, lubricating oil (including engine oil) for lubricating the sliding portion in the internal combustion engine prevents the pump body 1A from flowing into the pump body 1A.

The suction joint 17 (FIG. 2) is attached to the pump body 1A. The suction joint 17 is connected to a suction pipe 104 (FIG. 7) that supplies fuel from the fuel tank 101 of the vehicle, and the fuel passes through the suction pipe 104 (low pressure pipe) and is supplied into the high pressure pump. The suction filter in the suction joint 17 serves to prevent foreign matter existing between the fuel tank 101 and the low pressure fuel suction port 2A from being sucked into the high pressure fuel pump by the flow of fuel.

The fuel that has passed through the low-pressure fuel suction port 2A passes through the low-pressure fuel suction passage that communicates with the pump body 1A in the vertical direction and travels toward the pressure pulsation reduction mechanism 3, and the pressure pulsation reduction mechanism 3 and the suction passage 2B (low-pressure fuel passage). To the intake port 31B of the electromagnetic intake valve 300.

The discharge valve mechanism 500 provided at the outlet of the pressurizing chamber 4 includes a discharge valve sheet 51, a discharge valve 52 that contacts and separates from the discharge valve sheet 51, and a discharge valve spring that biases the discharge valve 52 toward the discharge valve sheet 51. 53, a discharge valve stopper 54 for determining the stroke (movement distance) of the discharge valve 52. The discharge valve stopper 54 is held by a plug 55. By welding the plug 55 to the contact portion 56 of the pump body 1A, the fuel is shut off from the outside.

In a state where there is no fuel differential pressure in the pressurizing chamber 4 and the discharge valve chamber 2F, the discharge valve 52 is pressed against the discharge valve seat 51 by the urging force of the discharge valve spring 53 and is closed. The discharge valve 52 is opened against the discharge valve spring 53 only when the fuel pressure in the pressurizing chamber 4 becomes higher than the fuel pressure in the discharge valve chamber 2F. The high-pressure fuel in the pressurizing chamber 4 is discharged to the common rail 108 through the discharge valve chamber 2F, the fuel discharge passage 2G, and the fuel discharge port 2C.

When the discharge valve 52 is opened, it comes into contact with the discharge valve stopper 54 and the stroke is limited. Therefore, the stroke of the discharge valve 52 is appropriately determined by the discharge valve stopper 54. With this configuration, a delay in closing the discharge valve 52 due to an excessively large stroke can be prevented. Therefore, it is possible to prevent the fuel discharged at high pressure into the discharge valve chamber 2F from flowing back into the pressurizing chamber 4 again, and to suppress a decrease in efficiency of the high pressure pump. Further, when the discharge valve 52 repeats the opening and closing movements, the discharge valve 52 is guided by the outer peripheral surface of the discharge valve stopper 54 so as to move only in the stroke direction. As described above, the discharge valve mechanism 500 serves as a check valve that restricts the direction of fuel flow.

As described above, the pressurizing chamber 4 includes the pump body 1A, the electromagnetic suction valve 300, the plunger 5, the cylinder 6, and the discharge valve mechanism 500.

When the plunger 5 moves in the direction of the cam 105 due to the rotation of the cam 105 and is in the suction stroke state, the volume of the pressurizing chamber 4 increases and the fuel pressure in the pressurizing chamber 4 decreases. In this process, when the fuel pressure in the pressurizing chamber 4 becomes lower than the pressure in the suction passage 2B, the valve body 30 is in an open state (valve open state). Therefore, the fuel passes through the opening formed by opening the valve body 30, passes through the communication hole provided in the pump body 1 A, and flows into the pressurizing chamber 4.

When the suction stroke ends, the plunger 5 starts to move upward and moves to the compression stroke. Here, the electromagnetic coil 43 remains in a non-energized state and no magnetic attractive force acts. The rod biasing spring 40 is set to have a biasing force necessary and sufficient to keep the valve body 30 open in a non-energized state, and such a high-pressure pump is called a normally open type.

The volume of the pressurizing chamber 4 decreases with the upward movement (compression) of the plunger 5. In this state, the fuel once sucked into the pressurizing chamber 4 is once again opened in the valve body 30 (suction valve). ) Is returned to the suction passage 2B through the opening, so that the pressure in the pressurizing chamber does not increase. This process is called a return process.

The relief valve 600 includes a relief valve cover 61, a ball valve 62, a relief valve presser 63, a spring 64, and a spring holder 65. The relief valve 600 is a valve that is configured to operate only when a problem occurs in the common rail 108 or a member ahead thereof and the pressure becomes abnormally high. The valve is opened only when the pressure is exceeded, and the fuel is returned to the pressurizing chamber. Therefore, it has a very strong spring 64.

The low pressure fuel chamber 8 is provided with a pressure pulsation reducing mechanism 3 for reducing the pressure pulsation generated in the high pressure pump from spreading to the fuel pipe 28. Further, a damper upper part 10B and a damper lower part 10C are provided above and below the pressure pulsation reducing mechanism 3 with a gap therebetween. When the fuel that has once flowed into the pressurizing chamber 4 is returned to the suction passage 2B through the valve body 30 of the opened valve again for capacity control, the low pressure fuel chamber 8 is driven by the fuel returned to the suction passage 2B. Pressure pulsation occurs.

However, the pressure pulsation reduction mechanism 3 provided in the low-pressure fuel chamber 8 is a metal diaphragm damper (metal) in which two corrugated disk-shaped metal plates are bonded together on the outer periphery and an inert gas such as argon is injected into the inside. The pressure pulsation is absorbed and reduced by the expansion and contraction of the metal damper.

The pressure pulsation reducing mechanism 3 is held in the low pressure fuel chamber 8 while being sandwiched between the first holding member 3A and the second holding member 3B. The first holding member 3A is disposed between the damper cover 16 and the pressure pulsation reducing mechanism 3 in the low pressure fuel chamber 8, and presses and holds the pressure pulsation reducing mechanism 3 toward the pump body 1A. The second holding member 3 B is disposed between the pump body 1 A and the pressure pulsation reducing mechanism 3 in the low pressure fuel chamber 8, and presses and holds the pressure pulsation reducing mechanism 3 toward the damper cover 16.

The plunger 5 has a large-diameter portion 5A and a small-diameter portion 5B, and the volume of the sub chamber 13A increases or decreases as the plunger reciprocates. The sub chamber 13A communicates with the low pressure fuel chamber 8 through a fuel passage. When the plunger 5 is lowered, fuel flows from the sub chamber 13A to the low pressure fuel chamber 8, and when the plunger 5 is raised, fuel flows from the low pressure fuel chamber 8 to the sub chamber 13A.

This makes it possible to reduce the fuel flow rate into and out of the pump during the pump intake stroke or return stroke, and to reduce the pressure pulsation generated inside the high pressure pump.

In recent years, in order to improve combustion efficiency, further increase in the fuel pressure discharged from the high-pressure pump has been demanded. Therefore, it is necessary to pressurize the fuel in the pressurizing chamber 4 more than ever. In the high pressure pump in which the rod 35 and the valve body 30 are separately formed as shown in FIG. 3 of the present embodiment, the valve body 30 is automatically turned on by the pressure chamber 4 becoming high pressure in the compression process. It collides with the seat member 31. As pressure increases further in the future, it is expected that when the valve body 30 collides with the valve seat member 31 or when the valve body 30 collides with the stopper 32, the impact is expected to become very large, so that the impact can be endured. A valve seat member 31 having a sufficient strength is required.

Therefore, in this embodiment, the valve seat member 31 and the rod guide 37 are also integrally formed. The rod guide 37 includes a guide portion 37 B that guides the anchor urging spring 41 (second spring) and a hole that guides the rod 35. Here, the rod guide 37 supports the anchor biasing spring 41 (second spring) on the side opposite to the movable core 36. The guide portion 37B is formed so that the outer diameter becomes smaller toward the movable core 36 side. Thereby, the anchor urging spring 41 (second spring) can be easily assembled to the guide portion 37B. The valve body 30 has a flat plate shape, and includes a flat plate portion 30A and a guide portion 30B protruding toward the pressurizing chamber.

(Structure of solenoid valve)
The structure of the electromagnetic suction valve 300 will be described with reference to FIG. In the electromagnetic suction valve 300, the magnetic flux generated by the electromagnetic coil 43 when energized causes the fixed core 39 (magnetic core), the second yoke 42B, the first yoke 42A, the third yoke 42C, and the movable core 36 (movable element) to be magnetized. By passing as a path and generating a magnetic attraction force between the fixed core 39 and the movable core 36 on the magnetic attraction surface S, and moving the movable core 36, the rod 35 and the valve body 30 arranged following them, A mechanism that sucks fuel and sends it to the pressurizing chamber 4.

Here, between the components constituting the magnetic path described above, except between the fixed core 39 that is a magnetic attraction surface and the movable core 36, and between the movable core 36 that is a sliding surface and the third yoke 42C. It is desirable that there is no air gap.

In this embodiment, the first yoke 42A and the third yoke 42C are press-fitted contact, and the fixed core 39 and the second yoke 42B are abutting contact, and are held between the second yoke 42B and the tomewa 45. Due to the spring force of the disc spring 44, the second yoke 42B is pressed against the fixed core 39 to ensure close contact. On the other hand, the second yoke 42B is inserted between the second yoke 42B and the first yoke 42A so that the second yoke 42B can be in close contact with the fixed core 39, and a necessary minimum air gap is provided. With the above structure, the air gap in the magnetic path of the electromagnetic intake valve can be minimized, and the magnetic efficiency of the magnetic intake valve can be improved. In place of the disc spring 44, a wave washer, a leaf spring, a coil spring, rubber or the like may be used after being compressed.

The movable core 36 has a first recessed portion 36A that is recessed toward the urging direction of the anchor urging spring 41 (second spring). The inner diameter of the first recessed portion 36A is equivalent (substantially the same) as the outer diameter of the anchor biasing spring 41 (second spring). Thereby, the spring force is transmitted in the axial direction without the anchor biasing spring 41 being inclined. Moreover, the movable core 36 has the 2nd recessed part 36B dented toward the urging | biasing direction of the rod urging | biasing spring 40 (1st spring). The inner diameter of the second recessed portion 36B is equal to the outer diameter of the rod biasing spring 40 (first spring). As a result, the spring force is transmitted in the axial direction without tilting the rod biasing spring 40. The inner diameter of the second recessed portion 36 B is equal to the outer diameter of the flange portion 35 A of the rod 35. Thereby, the flange portion 35A is guided by the inner diameter of the second recessed portion 36B.

It should be noted that the inner diameter of the second recess 36B and the outer diameter of the rod biasing spring 40 (first spring) are between the inner diameter of the first recess 36A and the outer diameter interference of the anchor biasing spring 41 (second spring). Between the inner diameter of the second recessed portion 36B and the outer diameter of the flange portion 35A may have a slight gap so as not to interfere with each other.

A rod 35 having a flange portion 35 A for locking the movable core 36 is disposed on the inner peripheral side of the movable core 36. Since the rod 35 has the flange portion 35 A, the movable core 36 can be locked, so that the rod 35 can move together with the movable core 36. The rod 35 is disposed inside the rod guide 37 having an anchor biasing spring 41 and a fuel passage 37 A that are in contact with the lower portion (the valve body 30 side) of the movable core 36. Thereby, the rod 35 drives the valve body 30.

The fixed core 39 is recessed toward the urging direction of the anchor urging spring 41 (second spring), and has a third dent portion 39A that accommodates the rod urging spring 40 (first spring). The inner diameter of the third recessed portion 39A of the fixed core 39 is equivalent to the inner diameter of the second recessed portion 36B of the movable core 36. Thereby, in a state where the movable core 36 is in contact with the fixed core 39 (valve closed state), the inner peripheral surface of the third recessed portion 39A and the inner peripheral surface of the second recessed portion 36B are connected. And the flange part 35A of the rod 35 is guided by those internal peripheral surfaces.

A rod urging spring 40 is arranged on the inner peripheral side of the fixed core 39 while being guided by a narrow diameter portion (columnar portion) at the base of the rod 35, and the rod 35 comes into contact with the valve body 30. Is applied to the valve seat member 31, that is, in the valve opening direction of the valve body. It is desirable that both ends of the rod biasing spring 40 be ground in order to push the rod 35 straight in the direction of the valve body 30 when the valve is opened.

In this case, one end of the rod urging spring 40 (first spring) on the side of the fixed core 39 has a surface (matching surface) parallel to the surface of the fixed core 39 with which one end of the rod urging spring 40 contacts, and is movable. The other end of the rod urging spring 40 (first spring) on the core 36 side has a surface parallel to the surface of the movable core 36 with which the other end of the rod urging spring 40 contacts.

The anchor biasing spring 41 is biased toward the movable core 36 in the direction of the flange portion 35A (rod collar portion) while its end is inserted into a cylindrical guide portion 37B provided on the center side of the rod guide 37 and is kept coaxial. It is arranged to give. Since the urging force of the anchor urging spring 41 is small and the wire diameter is thin, both end surfaces are not ground. That is, the cross section of the line of the anchor urging spring 41 (second spring) in contact with the rod guide 37 is circular. The cross section of the line of the anchor biasing spring 41 (second spring) that contacts the movable core 36 is also circular. Thereby, since it does not grind, manufacturing cost can be reduced.

In the case where the anchor urging spring 41 is not provided, the movable core 36 continues to move in the valve opening direction of the valve body 30 due to the inertial force, and collides with the guide portion 37B (central bearing portion) of the rod guide 37. There arises a problem that abnormal noise occurs in a part different from the part. For this reason, the anchor biasing spring 41 has an important function for preventing the above problem from occurring.

Since the valve body 30 needs to be closed quickly, it is preferable to set the spring force of the suction valve spring 33 as large as possible and set the spring force of the anchor biasing spring 41 small. Thereby, the deterioration of the flow efficiency due to the delay in closing the valve body 30 can be prevented.

The rod 35 is an inner peripheral portion of the flange portion 35 A, and is formed with a recessed portion 35 B that is recessed toward the inner peripheral side at a position in contact with the movable core 36. As a result, an escape portion when the movable core 36 comes into contact can be formed, so that damage due to the collision of the rod 35 or the movable core 36 can be prevented.
Further, the rod 35 is formed with an inclined portion 35C having a diameter that decreases toward the tip at the tip of the valve body 30 side.

With such a configuration, even when the movable core 36 is inserted into the rod 35 even if the core is slightly shifted, it can be easily assembled and the production efficiency can be increased. In addition, since the rod 35 is formed by a lathe process, a recessed portion that is recessed on the opposite side to the valve body 30 is formed at the distal end portion on the valve body 30 side.

The lower part of the rod 35 (the valve body 30 side) includes a valve body 30, a suction valve biasing spring 33, and a stopper 32. The valve body 30 is formed with a guide portion 30 B that protrudes toward the pressurizing chamber and is guided by the suction valve biasing spring 33. As the rod 35 moves, the valve body 30 moves by the gap of the valve body stroke 30E to control valve opening and closing. Further, the fuel supplied from the suction passage 2 B in the valve open state is supplied to the pressurizing chamber 4. The guide portion 30 B stops moving by being pressed into the housing of the electromagnetic suction valve 300 and colliding with the fixed stopper 32. The rod 35 and the valve body 30 are separate and independent structures. The valve body 30 is configured to close the flow path to the pressurizing chamber 4 by contacting the valve seat of the valve seat member 31 and to open the flow path to the pressurizing chamber 4 by moving away from the valve seat.

The moving amount of the movable core 36 is set larger than the moving amount of the valve body 30. This is because the valve body 30 is surely closed.

3, the so-called normally open electromagnetic suction valve 300 moves the rod 35 in the direction in which the valve element 30 is opened by the strong rod biasing spring 40 in a non-energized state. In other words, the rod biasing spring 40 (first spring) biases the rod 35 toward the valve body 30. When a control signal from the ECU 102 is applied to the electromagnetic suction valve 300, a current flows through the electromagnetic coil 43 via the terminal 46 (FIG. 1). When the current flows, a magnetic attractive force is generated on the magnetic attractive surface S of the fixed core 39. That is, the fixed core 39 generates a magnetic force.

The movable core 36 is attracted toward the fixed core 39 by the magnetic attractive force, and accordingly, the movable core 36 and the rod 35 locked to the movable core 36 are attracted in the valve closing direction. In other words, the movable core 36 is configured separately from the rod 35 and is driven by the fixed core 39 to drive the rod 35.

In most of the operation time of the electromagnetic suction valve 300, the rod 35 and the movable core 36 are pressed against each other by the rod urging spring 40 and the anchor urging spring 41 to the fixed core 39 side and the valve body 30 side. Repeat the reciprocating motion. At this time, the relationship between the rod biasing spring 40 and the anchor biasing spring 41 is such that if one spring is extended, the other spring is contracted, and if one spring is contracted, the other spring is extended. The anchor biasing spring 41 (second spring) biases the movable core 36 in the direction opposite to the biasing direction of the rod biasing spring 40 (first spring).

Since the rod biasing spring 40 and the anchor biasing spring 41 are coil springs, a rotational force is generated at the end face along with the expansion and contraction thereof, and the rotational force is transmitted to the rod 35 and the movable core 36, respectively. When the difference in rotational force exceeds the frictional force on the contact surface between the rod 35 and the movable core 36, the rod 35 and the movable core 36 rotate relative to each other, and wear occurs on the contact surface. Since this rotational force tends to increase as the spring force increases, it is desirable that the spring force of the rod biasing spring 40 and the anchor biasing spring 41 be close (equal) in order to reduce the difference in rotational force. On the other hand, as described above, the spring force of the anchor biasing spring 41 is preferably small from the viewpoint of the closing speed of the valve body 30.

From this point, in this embodiment, in a state where the movable core 36 is attracted to the fixed core 39, the spring force of the anchor biasing spring 41 is 10% to 20% with respect to the spring force of the rod biasing spring 40. It is set to be. In other words, when the movable core 36 is in contact with the fixed core 39 (valve closed state), the load of the anchor urging spring 41 (second spring) is 10% of the load of the rod urging spring 40 (first spring). Above and 20% or less. However, the load of the anchor biasing spring 41 (second spring) is only when the movable core 36 is in contact with the fixed core 39 in order to suppress wear due to relative rotation between the rod 35 and the movable core 36. The load on the rod urging spring 40 (first spring) may be 10% or more.

Furthermore, in the entire movable region of the movable core 36, the load of the anchor biasing spring 41 (second spring) is 10% or more and 20% or less of the load of the rod biasing spring 40 (first spring). It may be. Thereby, in the entire movable region of the movable core 36, wear due to relative rotation between the rod 35 and the movable core 36 can be suppressed.

In this embodiment, the winding direction of the rod urging spring 40 (first spring) and the anchor urging spring 41 (second spring) is the same direction. This is to prevent the rotational force generated by the expansion and contraction from being reversed when the winding direction is reversed and the difference in rotational force to be further increased. By making the winding direction the same, the rod urging spring 40 (first spring) and the anchor urging spring 41 (second spring) are rotated in the direction in which the rod urging spring 40 extends, and the anchor urging spring 41. The direction of rotation in the case of shrinking is the same. Thereby, the difference of rotational force becomes small.

As described above, when the magnetic biasing force overcomes the biasing force of the rod biasing spring 40 and the rod 35 moves away from the valve body 30, the biasing force and fuel by the suction valve biasing spring 33 are transferred to the suction passage. The valve body 30 is closed by the fluid force caused by flowing into 2B. After closing the valve, the fuel pressure in the pressurizing chamber 4 rises with the upward movement of the plunger 5, and when the pressure exceeds the pressure at the fuel discharge port 2 C, high-pressure fuel is discharged through the discharge valve mechanism 500, and the common rail 108 is discharged. Supplied. This stroke is called a discharge stroke.

The compression stroke of the plunger 5 (the upward stroke from the bottom dead center to the top dead center) consists of a return stroke and a discharge stroke. And the quantity of the high-pressure fuel discharged can be controlled by controlling the energization timing to the electromagnetic coil 43 of the electromagnetic suction valve 300. If the timing of energizing the electromagnetic coil 43 is advanced, the ratio of the return stroke during the compression stroke is small and the ratio of the discharge stroke is large. That is, the amount of fuel returned to the suction passage 2B is small and the amount of fuel discharged at high pressure is large. On the other hand, if the energization timing is delayed, the ratio of the return stroke during the compression stroke is large and the ratio of the discharge stroke is small. That is, the amount of fuel returned to the suction passage 2B is large and the amount of fuel discharged at high pressure is small. The energization timing to the electromagnetic coil 43 is controlled by a signal from the ECU 102.

By controlling the energization timing to the electromagnetic coil 43 as described above, it is possible to control so that the amount of fuel required by the internal combustion engine can be discharged appropriately.

Next, the structure of the anchor biasing spring 41 will be described with reference to FIG. FIG. 4 is a cross-sectional view showing the relationship between the maximum line length D1 and the wire diameter D2 of the anchor biasing spring 41 used in the high-pressure fuel pump of the present invention. When the anchor biasing spring 41 (second spring) is in the valve open state, the maximum line length D1 of the anchor biasing spring 41 is equal to or less than the wire diameter D2 of the anchor biasing spring 41. Thereby, the spring force of the anchor biasing spring 41 can be made larger than before.

Next, the structure of the anchor biasing spring 41 will be described with reference to FIG. FIG. 5 is a cross-sectional view showing the relationship between the straight line L1 connecting the center of the wire diameter of the anchor biasing spring 41 used in the high-pressure fuel pump of the present invention and the center line L2 of the flow path hole. The movable core 36 has a channel hole 36C that penetrates in the axial direction and indicates a hole through which fuel flows. A straight line L1 connecting the center of the wire diameter of the anchor urging spring 41 (second spring) is located on the radially outer side with respect to the center line L2 of the flow path hole 36C. Thereby, as shown in FIG. 6, a burr | flash becomes difficult to produce on the ridgeline 36D by the flow-

path hole

36C and 36 A of 1st dents. This is because the corner in the vicinity of the ridge line 36D becomes an obtuse angle.

As described above, according to this embodiment, it is possible to suppress wear due to relative rotation of the movable core and the rod.

In addition, this invention is not limited to an above-described Example, Various modifications are included.
For example, the above-described embodiments have been described in detail for easy understanding of the present invention, and are not necessarily limited to those having all the configurations described.

The section of the rod urging spring 40 (first spring) in contact with the fixed core 39 may be circular. Further, the cross section of the rod urging spring 40 (first spring) in contact with the movable core 36 may be circular. Thereby, manufacturing cost can be reduced.

DESCRIPTION OF SYMBOLS 1 ... High pressure fuel pump 1A ... Pump body 1B ... Flange 2A ... Low pressure fuel suction port 2B ... Suction passage 2C ... Fuel discharge port 2F ... Discharge valve chamber 2G ... Fuel discharge passage 3 ... Pressure pulsation reduction mechanism 3A ... First holding member 3B ... second holding member 4 ... pressurizing chamber 5 ... plunger 5A ... large diameter part 5B ... small diameter part 6 ... cylinder 7 ... ring 8 ... low pressure fuel chamber 10 ... tapet 10B ... damper upper part 10C ... damper lower part 13 ... seal holder 13A ... Sub chamber 14 ... Plunger seal 15 ... Retainer 16 ... Damper cover 17 ... Suction joint 18 ... Discharge joint 28 ... Fuel piping 30 ... Valve body 30A ... Flat plate portion 30B ... Guide portion 30E ... Valve body stroke 30P ... Fuel introduction passage 31 ... Valve Seat member 31B ... Suction port 32 ... Stopper 35 ... Rod 35A ... Flange 35B ... Recess 35C ... Inclined part 36 ... Movable core 36 ... 1st dent part 36B ... 2nd dent part 36C ... Channel hole 37 ... Rod guide 37A ... Fuel passage 37B ... Guide part 39 ... Fixed core 39A ... 3rd dent part 42A ... 1st yoke 42B ... 2nd yoke 42C ... 3rd yoke 43 ... Electromagnetic coil 45 ... Tomewa 46 ... Terminal 51 ... Discharge valve seat 52 ... Discharge valve 54 ... Discharge valve stopper 55 ... Plug 56 ... Contact part 61 ... Relief valve cover 62 ... Ball valve 65 ... Holder 101 ... Fuel Tank 102 ... ECU
DESCRIPTION OF SYMBOLS 103 ... Feed pump 104 ... Suction piping 105 ... Cam 107 ... Pressure sensor 108 ... Common rail 110 ... Injector 112 ... Cylinder head 300 ... Electromagnetic suction valve 500 ... Discharge valve mechanism 600 ... Relief valve

Claims

The disc,
A rod for driving the valve body;
A fixed core that generates magnetic force;
A movable core configured to be separated from the rod and driving the rod by being sucked by the fixed core;
A first spring that urges the rod toward the valve body;
A second spring that biases the movable core in a direction opposite to the biasing direction of the first spring;
A high-pressure fuel pump configured so that a load of the second spring is 10% or more of a load of the first spring when the movable core is in contact with the fixed core.
The high-pressure fuel pump according to claim 1,
A high-pressure fuel pump configured so that a load of the second spring is 10% or more and 20% or less of a load of the first spring in a state where the movable core is in contact with the fixed core.
The high-pressure fuel pump according to claim 2,
A high-pressure fuel pump configured so that the load of the second spring is 10% or more and 20% or less of the load of the first spring in the entire movable region of the movable core.
The high-pressure fuel pump according to claim 1,
A rod guide having a guide portion for guiding the second spring and a hole for guiding the rod;
The guide portion is
A high-pressure fuel pump formed such that an outer diameter thereof decreases toward the movable core.
The high-pressure fuel pump according to claim 1,
A rod guide for supporting the second spring on the side opposite to the movable core;
The cross section of the line of the second spring in contact with the rod guide is
High-pressure fuel pump configured to be circular.
The high-pressure fuel pump according to claim 5,
The cross section of the line of the second spring in contact with the movable core is
High-pressure fuel pump configured to be circular.
The high-pressure fuel pump according to claim 1,
One end of the first spring on the fixed core side is
Having a surface parallel to the surface of the fixed core with which one end of the first spring contacts;
The other end of the first spring on the movable core side is
A high-pressure fuel pump having a surface parallel to the surface of the movable core with which the other end of the first spring contacts.
The high-pressure fuel pump according to claim 1,
The first spring and the second spring are:
A high-pressure fuel pump configured so that a rotation direction when the first spring extends and a rotation direction when the second spring contracts are the same.
The high-pressure fuel pump according to claim 1,
A high-pressure fuel pump in which the winding direction of the first spring and the second spring is the same.
The high-pressure fuel pump according to claim 1,
The second spring is a high-pressure fuel pump configured so that a maximum line length of the second spring is equal to or less than a wire diameter of the second spring in a valve open state.
The high-pressure fuel pump according to claim 1,
The movable core is
Having a first recess recessed toward the biasing direction of the second spring;
The inner diameter of the first recess is
A high-pressure fuel pump that is equivalent to the outer diameter of the second spring.
The high-pressure fuel pump according to claim 1,
The movable core is
Having a second recessed portion recessed toward the biasing direction of the first spring;
The inner diameter of the second recess is
A high-pressure fuel pump that is equivalent to the outer diameter of the first spring.
The high-pressure fuel pump according to claim 12,
The rod is
A flange portion for locking the movable core;
The inner diameter of the second recess is
A high-pressure fuel pump having the same outer diameter as the flange portion.
The high-pressure fuel pump according to claim 13,
The fixed core is
Dented toward the urging direction of the second spring, and having a third dent to accommodate the first spring,
The inner diameter of the third recess is
A high-pressure fuel pump that is equivalent to the inner diameter of the second recess.
The high-pressure fuel pump according to claim 1,
The movable core is
A passage hole that penetrates in the axial direction and indicates a hole through which the fuel flows,
A straight line connecting the center of the diameter of the second spring,
A high-pressure fuel pump configured to be located radially outside the center line of the flow path hole.