JP6938776B2 - High pressure fuel supply pump - Google Patents

Description

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

Among internal combustion engines of automobiles, high-pressure fuel pumps equipped with an electromagnetic suction valve that increases the pressure of fuel and discharges a desired fuel flow rate are widely used in direct injection type internal combustion engines that inject directly into the combustion chamber. ..

Patent Document 1 describes a high-pressure fuel supply provided with an electromagnetic suction valve for adjusting the amount of fuel sucked into the pressurizing chamber, a discharge valve for discharging fuel from the pressurizing chamber, and a plunger capable of reciprocating the pressurizing chamber. A pump, the electromagnetic suction valve has an electromagnetic coil, a suction valve, and a movable part that can operate the suction valve in the valve closing direction by a magnetic attraction force when the electromagnetic coil is energized, and the movable part is magnetic attraction. It consists of an anchor part that drives the suction valve in the valve closing direction by force and collides with the fixing member to stop the movement, and a rod part that is driven in conjunction with the anchor part and can continue the movement even after the anchor part stops the movement. The electromagnetic suction valve has a first spring that urges the suction valve in the closing direction, a second spring that urges the suction valve in the opening direction via the rod portion, and a force that presses the rod portion against the anchor portion. It is provided with a third spring to be applied to the part. "

According to the invention described in Patent Document 1, after the electromagnetic force is released, the rod moves to the suction valve side by the rod urging spring and stops colliding with the suction valve, the anchor tries to continue the movement by the inertial force. By the anchor urging spring of the present invention, the anchor is localized at a specified position so that the anchor does not collide with another member and generate an abnormal noise, and it is desired to be localized at a position where suction is possible. Flow control is possible.

International Publication No. 2016/031378

However, in the high-pressure fuel pump described in Patent Document 1, the separated anchor (movable core) and rod are urged so as to be pressed against each other by two springs. Generally, a coil spring generates a rotational force on both end faces as it compresses and expands itself.
Due to this rotational force, relative rotation occurs 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 capable of suppressing wear due to relative rotation of a movable core and a rod.

In order to achieve the above object, an example of the present invention is configured as a valve body, a rod for driving the valve body, a fixed core for generating a magnetic force, and a separate body from the rod, and is attracted to the fixed core. The movable core that drives the rod, the first spring that urges the rod toward the valve body, and the movable core that urges the rod in the direction opposite to the urging direction of the first spring. In a high-pressure fuel pump provided with a urging second spring, the load of the second spring is configured to be 10% or more of the load of the first spring when the movable core is in contact with the fixed core. is, the second spring, in the open state, the maximum line between the length of the second spring, Ru is configured such that the line diameter or less of a said second spring.

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

It is a vertical sectional view of the high pressure fuel pump of this invention. It is a horizontal sectional view seen from above of the high pressure fuel pump of this invention. It is an enlarged vertical sectional view of the electromagnetic suction valve of the high pressure fuel pump of this invention. It is sectional drawing which shows the relationship between the maximum line length and the wire diameter of the anchor urging spring used for the high pressure fuel pump of this invention. It is sectional drawing which shows the relationship between the straight line connecting the wire diameter center of the anchor urging spring used for the high pressure fuel pump of this invention, and the center line of a flow path hole. It is a perspective view of the movable core used in the high pressure fuel pump of this invention. The block diagram of the engine system to which the high pressure fuel pump of this invention was applied is shown.

Hereinafter, examples of the high-pressure fuel pump of the present invention will be described in detail with reference to the drawings. In each drawing, the same reference numerals indicate 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. 7. The part surrounded by the broken line indicates the main body of the high-pressure fuel pump 1 (hereinafter referred to as the high-pressure pump), and the mechanism / parts shown in the broken line indicate that the pump body 1A is integrally incorporated. ..

The fuel in the fuel tank 101 is pumped 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 through the suction pipe 104 to the low pressure fuel suction port 2A of the high pressure pump. 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 that constitutes the capacity variable mechanism via the pressure pulsation reduction 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. The cam 105 (cam mechanism) of the engine gives the plunger 5 the power to reciprocate. Due to the reciprocating motion of the plunger 5, fuel is sucked from the valve body 30 in the descending stroke of the plunger 5, and the fuel is pressurized in the ascending stroke. When the fuel is pressurized, the fuel is pressure-fed to the common rail 108 on which the pressure sensor 107 is mounted via the discharge valve mechanism 500 (FIG. 2).

Then, the injector 110 injects fuel into the combustion chamber based on the signal from the ECU 102. This 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, but it can also be applied to other systems. Upon receiving the signal from the ECU 102 to the electromagnetic suction valve 300, the high-pressure pump discharges the desired fuel flow rate toward the common rail side.

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

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

An O-ring 7 is fitted into the pump body 1A in order to seal between the cylinder head 112 and the pump body 1A. This prevents the engine oil from leaking to the 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 into 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 by the discharge joint 18.

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

A cam 105 attached to a camshaft of an internal combustion engine is arranged at the lower end of the plunger 5. Further, a tappet 10 is provided which converts the rotary motion of the cam 105 into a vertical motion and transmits the motion to the plunger 5. The plunger 5 is crimped to the tappet 10 by the spring 12 via the retainer 15. With this configuration, the plunger 5 can be reciprocated up and down with the rotational movement of the cam 105.

Further, the plunger seal 14 held at the lower end of the inner circumference of the seal holder 13 is installed so as to slidably contact the outer periphery of the plunger 5 at the lower portion in the drawing of the cylinder 6.
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) that lubricates the sliding portion in the internal combustion engine is prevented from flowing into the pump body 1A.

A 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 is supplied to the inside of the high-pressure pump through the suction pipe 104 (low-pressure pipe). 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 goes to the pressure pulsation reduction mechanism 3 through the low-pressure fuel suction passage that communicates vertically with the pump body 1A, and goes to the pressure pulsation reduction mechanism 3 and the suction passage 2B (low-pressure fuel flow path). It reaches the suction port 31B of the electromagnetic suction valve 300 via the above.

The discharge valve mechanism 500 provided at the outlet of the pressurizing chamber 4 is a discharge valve spring that urges the discharge valve seat 51, the discharge valve 52 that comes into contact with and separates from the discharge valve seat 51, and the discharge valve 52 toward the discharge valve seat 51. It is composed of 53 and a discharge valve stopper 54 that determines the stroke (moving distance) of the discharge valve 52. The discharge valve stopper 54 is held by the plug 55. The fuel is shut off from the outside by welding the plug 55 to the contact portion 56 of the pump body 1A.

When there is no fuel differential pressure between the pressurizing chamber 4 and the discharge valve chamber 2F, the discharge valve 52 is crimped to the discharge valve seat 51 by the urging force of the discharge valve spring 53 to be in a closed state. Only when the fuel pressure in the pressurizing chamber 4 becomes higher than the fuel pressure in the discharge valve chamber 2F, the discharge valve 52 opens against the discharge valve spring 53. Then, the high-pressure fuel in the pressurizing chamber 4 is discharged to the common rail 108 via 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, it is possible to prevent a delay in closing the discharge valve 52 due to an excessively large stroke. Therefore, it is possible to prevent the fuel discharged at high pressure to the discharge valve chamber 2F from flowing back into the pressurizing chamber 4 again, and it is possible to suppress a decrease in efficiency of the high pressure pump. Further, when the discharge valve 52 repeats the valve opening and closing movements, the discharge valve 52 is guided by the outer peripheral surface of the discharge valve stopper 54 so that the discharge valve 52 moves only in the stroke direction. By doing so, the discharge valve mechanism 500 becomes a check valve that limits the fuel flow direction.

As described above, the pressurizing chamber 4 includes a pump body 1A, an electromagnetic suction valve 300, a plunger 5, a cylinder 6, and a 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. When the fuel pressure in the pressurizing chamber 4 becomes lower than the pressure in the suction passage 2B in this stroke, the valve body 30 is in the 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 1A, and flows into the pressurizing chamber 4.

When the inhalation stroke is completed, the plunger 5 shifts to an ascending motion and shifts to a compression stroke. Here, the electromagnetic coil 43 remains in a non-energized state, and the magnetic attraction force does not act. The rod urging spring 40 is set to have a urging 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 ascending movement (compression) of the plunger 5, but in this state, the fuel once sucked into the pressurizing chamber 4 is reopened as 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 rise. This process is called the return process.

The relief valve 600 includes a relief valve cover 61, a ball valve 62, a relief valve retainer 63, a spring 64, and a spring holder 65. The relief valve 600 is a valve configured to operate only when a problem occurs in the common rail 108 or a member beyond the common rail 108 and the pressure becomes abnormally high, and the pressure in the common rail 108 or the member beyond the common rail 108 sets a threshold value. It has the role of opening the valve only when it exceeds the pressure and returning the fuel 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 portion 10B and a damper lower portion 10C are provided above and below the pressure pulsation reducing mechanism 3 at intervals. When the fuel once flowing into the pressurizing chamber 4 is returned to the suction passage 2B through the valve body 30 of the intake valve in the opened state again for capacity control, the low pressure fuel chamber 8 is returned by the fuel returned to the suction passage 2B. Pressure pulsation occurs in.

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 thereof and an inert gas such as argon is injected inside. It is formed of a damper), and the pressure pulsation is absorbed and reduced by the expansion and contraction of this metal damper.

The pressure pulsation reducing mechanism 3 is held in the low pressure fuel chamber 8 in a state of being sandwiched between the first holding member 3A and the second holding member 3B. The first holding member 3A is arranged 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 3B is arranged between the pump body 1A 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 due to the reciprocating motion of the plunger. The sub chamber 13A communicates with the low pressure fuel chamber 8 by a fuel passage. When the plunger 5 is lowered, a fuel flow is generated from the sub chamber 13A to the low pressure fuel chamber 8, and when the plunger 5 is raised, a fuel flow is generated from the low pressure fuel chamber 8 to the sub chamber 13A.

This makes it possible to reduce the fuel flow rate inside and outside the pump during the suction stroke or the return stroke of the pump, and has a function of reducing the pressure pulsation generated inside the high-pressure pump.

In recent years, in order to improve combustion efficiency, it has been required to further increase the discharge fuel pressure of a high-pressure pump. Therefore, it is necessary to pressurize the fuel in the pressurizing chamber 4 more than ever. In a high-pressure pump in which the rod 35 and the valve body 30 are separately formed as shown in FIG. 3 of this embodiment, the valve body 30 automatically becomes a valve when the pressure chamber 4 becomes high pressure in the compression step. It collides with the seat member 31. In the future, as the pressure is further increased, it is expected that the impact when the valve body 30 collides with the valve seat member 31 or when the valve body 30 collides with the stopper 32 becomes very large, so that the impact can be withstood. A valve seat member 31 having a high strength is required.

Therefore, in this embodiment, the valve seat member 31 and the rod guide 37 are also integrally molded. The rod guide 37 has a guide portion 37B for guiding the anchor urging spring 41 (second spring) and a hole for guiding the rod 35. Here, the rod guide 37 supports the anchor urging 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 side of the movable core 36. As a result, 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 side.

(Solenoid valve structure)
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 by energization magnetizes 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). Passing as a path, a magnetic attraction force is generated between the fixed core 39 and the movable core 36 on the magnetic attraction surface S, and the movable core 36, the rod 35, and the valve body 30 arranged following them are moved. It refers to a mechanism that sucks in fuel and sends it to the pressurizing chamber 4.

Here, among the parts constituting the above-mentioned magnetic path, except between the fixed core 39 and the movable core 36 which are the magnetic attraction surface portions and between the movable core 36 and the third yoke 42C which are the sliding surfaces. Therefore, it is desirable that there is no air gap.

In this embodiment, the first yoke 42A and the third yoke 42C are in press-fitting contact, and the fixed core 39 and the second yoke 42B are in abutment contact, and are held between the second yoke 42B and the tomewa 45. The spring force of the disc spring 44 presses the second yoke 42B 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 brought into close contact with the fixed core 39, and the minimum necessary air gap is provided. With the above structure, the air gap in the magnetic path of the electromagnetic suction valve can be minimized, and the magnetic efficiency of the magnetic suction valve can be improved. Instead of the disc spring 44, a wave washer, a leaf spring, a coil spring, rubber, or the like may be compressed and used.

The movable core 36 has a first recessed portion 36A that is recessed in the biasing direction of the anchor urging spring 41 (second spring). The inner diameter of the first recessed portion 36A is equal to (almost the same) as the outer diameter of the anchor urging spring 41 (second spring). As a result, the spring force is transmitted in the axial direction without tilting the anchor urging spring 41. Further, the movable core 36 has a second recessed portion 36B that is recessed in the biasing direction of the rod urging spring 40 (first spring). The inner diameter of the second recessed portion 36B is equivalent to the outer diameter of the rod urging spring 40 (first spring). As a result, the spring force is transmitted in the axial direction without tilting the rod urging spring 40. The inner diameter of the second recessed portion 36B is equivalent to the outer diameter of the flange portion 35A of the rod 35. As a result, the flange portion 35A is guided by the inner diameter of the second recessed portion 36B.

Between the inner diameter of the first recess 36A and the outer diameter interference of the anchor urging spring 41 (second spring), the inner diameter of the second recess 36B and the outer diameter of the rod urging spring 40 (first spring). Each of 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 in design.

On the inner peripheral side of the movable core 36, a rod 35 provided with a flange portion 35A for locking the movable core 36 is arranged. Since the rod 35 has the flange portion 35A, the movable core 36 can be locked, so that the rod 35 can move together with the movable core 36. Further, the rod 35 is arranged inside the rod guide 37 provided with the anchor urging spring 41 in contact with the lower portion (valve body 30 side) of the movable core 36 and the fuel passage 37A. As a result, the rod 35 drives the valve body 30.

The fixed core 39 has a third recessed portion 39A that is recessed in the urging direction of the anchor urging spring 41 (second spring) and 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. As a result, 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. Then, the flange portion 35A of the rod 35 is guided by their inner peripheral surfaces.

A rod urging spring 40 is arranged on the inner peripheral side of the fixed core 39 by being guided by a small diameter portion (cylindrical portion) at the base of the rod 35, and the rod 35 comes into contact with the valve body 30 to contact the valve body 30. Is applied in the direction of pulling away from the valve seat member 31, that is, in the valve opening direction of the valve body. It is desirable that the rod urging spring 40 grinds both end faces 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 is in contact, and is movable. The other end of the rod urging spring 40 (first spring) on the side of the core 36 has a surface parallel to the surface of the movable core 36 to which the other end of the rod urging spring 40 contacts.

The anchor urging spring 41 has a direction end inserted into a cylindrical guide portion 37B provided on the center side of the rod guide 37 to maintain coaxiality, while urging the movable core 36 in the direction of the flange portion 35A (rod brim portion). Is arranged to give. Since the anchor urging spring 41 has a small urging force and a small wire diameter, 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. Further, the cross section of the line of the anchor urging spring 41 (second spring) in contact with the movable core 36 is also circular. As a result, since grinding is not performed, the manufacturing cost can be reduced.

In the case of the configuration without the anchor urging spring 41, the movable core 36 continues to move in the valve opening direction of the valve body 30 due to the inertial force, collides with the guide portion 37B (center bearing portion) of the rod guide 37, and the collision occurs. There is a problem that abnormal noise is generated in the part different from the part. Therefore, the anchor urging spring 41 has an important function for not causing the above problem.

Since the valve body 30 needs to be closed quickly, it is preferable to set the spring force of the suction valve spring 33 to be as large as possible and the spring force of the anchor urging spring 41 to be small. This makes it possible to prevent deterioration of the flow rate efficiency due to the delay in closing the valve body 30.

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

With such a configuration, even if the center is slightly misaligned when the movable core 36 is inserted into the rod 35, it can be easily incorporated and the production efficiency can be improved. Since the rod 35 is formed by lathe processing, a recessed portion is formed at the tip end portion on the valve body 30 side, which is recessed on the opposite side to the valve body 30.

A valve body 30, a suction valve urging spring 33, and a stopper 32 are provided on the lower portion (valve body 30 side) of the rod 35. The valve body 30 is formed with a guide portion 30B that protrudes toward the pressurizing chamber and is guided by the suction valve urging spring 33. The valve body 30 moves by the gap of the valve body stroke 30E as the rod 35 moves, and controls valve opening and closing. Further, the fuel supplied from the suction passage 2B in the valve open state is supplied to the pressurizing chamber 4. The guide portion 30B stops moving when it is press-fitted into the housing of the electromagnetic suction valve 300 and collides with the fixed stopper 32. The rod 35 and the valve body 30 are separate and have an independent structure. The valve body 30 is configured to close the flow path to the pressurizing chamber 4 by coming into contact with 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 amount of movement of the movable core 36 is set to be larger than the amount of movement of the valve body 30. This is because the valve body 30 is surely closed.

In the so-called normally open type electromagnetic suction valve 300 shown in FIG. 3, the rod 35 is moved in the direction in which the valve body 30 is opened by the strong rod urging spring 40 in the non-energized state. In other words, the rod urging spring 40 (first spring) urges the rod 35 toward the valve body 30. When the 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 an electric current flows, a magnetic attraction force is generated on the magnetic attraction surface S of the fixed core 39. That is, the fixed core 39 generates a magnetic force.

The movable core 36 is attracted to the fixed core 39 side by the magnetic attraction 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 drives the rod 35 by being sucked by the fixed core 39.

For most of the operating 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 toward the fixed core 39 side and the valve body 30 side. Repeat the reciprocating motion of. At this time, the relationship between the rod urging spring 40 and the anchor urging spring 41 is such that when one spring expands, the other spring contracts, and when one spring contracts, the other spring expands. The anchor urging spring 41 (second spring) urges the movable core 36 in a direction opposite to the urging direction of the rod urging spring 40 (first spring).

Since the rod urging spring 40 and the anchor urging spring 41 are coil springs, a rotational force is generated on the end face as the rod urging spring 40 and the anchor urging spring 41 expand and contract, 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 of the contact surface between the rod 35 and the movable core 36, the rod 35 and the movable core 36 rotate relatively, 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 forces of the rod urging spring 40 and the anchor urging spring 41 are close (equivalent) in order to reduce the difference in rotational force. On the other hand, as already described, from the viewpoint of the closing speed of the valve body 30, it is desirable that the spring force of the anchor urging spring 41 is small.

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

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

In this embodiment, the winding direction of the rod urging spring 40 (first spring) and the anchor urging spring 41 (second spring) are the same. This is to avoid that when the winding direction is reversed, the rotational force generated by expansion and contraction is also in the opposite direction, and the difference in rotational force becomes even larger. By making the winding direction the same, the rod urging spring 40 (first spring) and the anchor urging spring 41 (second spring) have the rotation direction when the rod urging spring 40 extends and the anchor urging spring 41. Is the same as the direction of rotation when shrinking. As a result, the difference in rotational force becomes small.

As described above, the magnetic urging force overcomes the urging force of the rod urging spring 40, and the rod 35 moves in the direction away from the valve body 30, so that the urging force and fuel by the suction valve urging spring 33 enter the suction passage. The valve body 30 closes due to the fluid force generated by flowing into 2B. After the valve is closed, the fuel pressure in the pressurizing chamber 4 rises with the ascending motion of the plunger 5, and when the pressure exceeds the pressure in the fuel discharge port 2C, high-pressure fuel is discharged through the discharge valve mechanism 500 to the common rail 108. Be supplied. This process is called a discharge process.

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

By controlling the energization timing of 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 appropriately discharged.

Next, the structure of the anchor urging 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 urging spring 41 used in the high-pressure fuel pump of the present invention. In the valve open state of the anchor urging spring 41 (second spring), the maximum line length D1 of the anchor urging spring 41 is equal to or less than the wire diameter D2 of the anchor urging spring 41. As a result, the spring force of the anchor urging spring 41 can be made larger than before.

Next, the structure of the anchor urging 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 wire diameter centers of the anchor urging 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 flow path hole 36C that penetrates in the axial direction and indicates a hole through which fuel flows. The straight line L1 connecting the center lines of the anchor urging spring 41 (second spring) with respect to the center line L2 of the flow path hole 36C is located radially outside. As a result, as shown in FIG. 6, burrs are less likely to occur on the ridge line 36D due to the flow path hole 36C and the first recessed portion 36A. This is because the angle near the ridge line 36D becomes an obtuse angle.

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

The present invention is not limited to the above-described examples, and includes various modifications.
For example, the above-described examples have been described in detail in order to explain the present invention in an easy-to-understand manner, and are not necessarily limited to those having all the described configurations.

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

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 ... 2nd 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 ... Tappet 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 part 30B ... Guide part 30E ... Valve body stroke 30P ... Fuel introduction passage 31 ... Valve Seat member 31B ... Suction port 32 ... Stopper 35 ... Rod 35A ... Flange 35B ... Recessed portion 35C ... Inclined portion 36 ... Movable core 36A ... First recessed portion 36B ... Second recessed portion 36C ... Flow path hole 37 ... Rod guide 37A ... Fuel passage 37B ... Guide portion 39 ... Fixed core 39A ... Third recessed portion 42A ... First yoke 42B ... Second yoke 42C ... Third yoke 43 ... Electromagnetic coil 45 ... Tomewa 46 ... Terminal 51 ... Discharge valve seat 52 ... Discharge Valve 54 ... Discharge valve stopper 55 ... Plug 56 ... Contact portion 61 ... Relief valve cover 62 ... Ball valve 65 ... Holder 101 ... Fuel tank 102 ... ECU
103 ... Feed pump 104 ... Suction pipe 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 (14)

A valve body, a rod for driving the valve body, a fixed core for generating a magnetic force, a movable core which is formed separately from the rod and drives the rod by being attracted to the fixed core, and the rod. In a high-pressure fuel pump provided with a first spring for urging the movable core toward the valve body and a second spring for urging the movable core in a direction opposite to the urging direction of the first spring. The load of the second spring is configured to be 10% or more of the load of the first spring in a state where the movable core is in contact with the fixed core .
The second spring is a high-pressure fuel pump configured such that the maximum line length of the second spring is equal to or less than the wire diameter of the second spring in the valve open state. In the high-pressure fuel pump according to claim 1,
A high-pressure fuel pump configured such that the load of the second spring is 10% or more and 20% or less of the load of the first spring when the movable core is in contact with the fixed core. In the high-pressure fuel pump according to claim 2.
A high-pressure fuel pump configured such 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. In 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 is provided.
The guide unit
A high-pressure fuel pump formed so that the outer diameter becomes smaller toward the movable core side. In the high-pressure fuel pump according to claim 1,
A rod guide that supports the second spring on the opposite side of the movable core is provided.
The cross section of the line of the second spring in contact with the rod guide is
A high-pressure fuel pump configured to have a circular shape. In 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
A high-pressure fuel pump configured to have a circular shape. In the high-pressure fuel pump according to claim 1,
One end of the first spring on the side of the fixed core
It has a surface parallel to the surface of the fixed core with which one end of the first spring is in contact.
The other end of the first spring on the side of the movable core
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 is in contact. In the high-pressure fuel pump according to claim 1,
The first spring and the second spring
A high-pressure fuel pump configured so that the rotation direction when the first spring is extended and the rotation direction when the second spring is contracted are the same. In the high-pressure fuel pump according to claim 1,
A high-pressure fuel pump in which the winding directions of the first spring and the second spring are the same. A valve body, a rod for driving the valve body, a fixed core for generating a magnetic force, a movable core which is formed separately from the rod and drives the rod by being attracted to the fixed core, and the rod. The movable core includes a first spring that urges the movable core toward the valve body, and a second spring that urges the movable core in a direction opposite to the urging direction of the first spring. In a high-pressure fuel pump configured such that the load of the second spring is 10% or more of the load of the first spring in a state of being in contact with the fixed core.
The movable core is
It has a first recessed portion that is recessed in the urging direction of the second spring.
The inner diameter of the first recess is
A high-pressure fuel pump having the same outer diameter as the second spring. A valve body, a rod for driving the valve body, a fixed core for generating a magnetic force, a movable core which is formed separately from the rod and drives the rod by being attracted to the fixed core, and the rod. The movable core includes a first spring that urges the movable core toward the valve body, and a second spring that urges the movable core in a direction opposite to the urging direction of the first spring. In a high-pressure fuel pump configured such that the load of the second spring is 10% or more of the load of the first spring in a state of being in contact with the fixed core.
The movable core is
It has a second recess that is recessed in the urging direction of the first spring.
The inner diameter of the second recess is
A high-pressure fuel pump having the same outer diameter as the first spring. In the high-pressure fuel pump according to claim 11.
The rod
It has a flange portion that locks the movable core, and has a flange portion.
The inner diameter of the second recess is
A high-pressure fuel pump having the same outer diameter as the flange portion. In the high-pressure fuel pump according to claim 12,
The fixed core
It has a third recess that is recessed in the urging direction of the second spring and accommodates the first spring.
The inner diameter of the third recess is
A high-pressure fuel pump having the same inner diameter as the second recess. A valve body, a rod for driving the valve body, a fixed core for generating a magnetic force, a movable core which is formed separately from the rod and drives the rod by being attracted to the fixed core, and the rod. The movable core includes a first spring that urges the movable core toward the valve body, and a second spring that urges the movable core in a direction opposite to the urging direction of the first spring. In a high-pressure fuel pump configured such that the load of the second spring is 10% or more of the load of the first spring in a state of being in contact with the fixed core.
The movable core is
It has a flow path hole that penetrates in the axial direction and shows a hole through which fuel flows.
The straight line connecting the center of the wire diameter of the second spring is
A high-pressure fuel pump configured to be located radially outside the center line of the flow path hole.

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