JPH10122082A - Accumulative fuel injector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a compact, easy-to-work and durable fuel injector which suppresses the leakage of fuel. SOLUTION: A spherical member 43 is made of ceramics or cemented carbide, and a flat plate 51 is coated at its base metal with a hard anodic oxidation coating 71. The base metal is made of high-speed tool steel or high-temperature tempered die steel, and is coated at its seat part for the spherical member 43 with a film of TiN, CrN, DLC or the like as the hard anodic oxidation coating 71. Since that formation of the spherical member 43 and the seat part of the flat plate 51 out of abrasion-resistant materials suppresses their abrasion resulting from collision between the spherical member 43 and the flat plate 51 as well as caused by hard contaminant contained in fuel, the leakage of fuel out of a pressure control chamber is suppressed at the closing of a solenoid valve and desired characteristics of fuel injection are accurately obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure-accumulation fuel injection device in which high-pressure fuel is accumulated in a common rail, which is a kind of surge tank, and the accumulated high-pressure fuel is injected from an electromagnetically controlled injector. It is.

[0002]

2. Description of the Related Art Conventionally, high-pressure fuel is sent to a common rail under high pressure by a high-pressure supply pump to accumulate pressure, and the accumulated high-pressure fuel is supplied to an electromagnetically controlled injector. Japanese Patent Application Laid-Open No. Hei 5-
The ones disclosed in JP-A-133296 and JP-A-1-232161 are known.

The fuel injection device disclosed in JP-A-5-133296 and JP-A-1-232161 has a pressure control chamber for introducing high-pressure fuel to a valve member that opens and closes an injection hole on a side opposite to the injection hole. By opening and closing the pressure control chamber and the low-pressure side with an electromagnetic two-way valve, the opening and closing of the injection hole by the valve member is controlled. The movable member of the solenoid valve and the non-movable member as a valve seat are in close contact with each other in a plane, so that the communication between the pressure control chamber and the low pressure side is cut off.
Processing the sheet portion into a planar shape is easier than processing the sheet portions of a movable member and a non-movable member having a conical seat surface. Further, since the seat area can be increased, abrasion at the seat portion is reduced, and good sealing performance can be maintained.

However, in the apparatus disclosed in Japanese Patent Application Laid-Open No. 5-133296, the force received by the seat portion of the movable member from the fuel pressure in the pressure control chamber acts in the valve opening direction of the solenoid valve, so that the movable member is not opened. The spring force seated on the movable member increases. For this reason, it is necessary to increase the attraction force of the solenoid valve that separates the movable member from the non-movable member against this spring force, so that there is a problem that the size of the solenoid valve increases.

[0005] Further, in the system disclosed in Japanese Patent Application Laid-Open No. 1-2232161, the pressure of the high-pressure fuel is 500 kg.
/ cm ² (about 50MPa), but 100MPa
To use the above two-way solenoid valve for switching high pressure fuel,
It is considered that if the contact area between the movable member and the non-movable member is too large, the hydraulic load acting in the valve opening direction of the solenoid valve increases, which is not suitable for practical use. Further, when the set stroke amount of the movable member is small or at the time of a low stroke immediately after the valve is opened, the facing area between the movable member and the non-movable member is large, so that the flow coefficient becomes extremely small, so that the pressure loss becomes excessively large. There's a problem. For this reason, the opening pressure does not drop sufficiently even when the movable member separates from the non-movable member, and a time delay occurs until the pressure actually drops even after the valve opening signal is sent to the solenoid valve. There is. Further, the structure in which the movable member is easily separated from the non-movable member by the fuel groove means that the movable member acts as a repulsive force when the movable member is seated on the non-movable member. The effect of reducing the bounce of can not be expected. Further, since the diameter of the injector is increased by making the contact area between the movable member and the non-movable member significantly larger than the opening area, it is not suitable for use in a small diesel engine.

The present applicant discloses a fuel injection device which solves such a problem in Japanese Patent Application No. 7-190664. In this fuel injection device, by providing a fuel release passage in the contact area between the movable member and the non-movable member of the solenoid valve, the contact area is reduced, and secure sealing performance is ensured without increasing the seat pressure. doing.

[0007]

However, in the fuel injection device disclosed in Japanese Patent Application No. Hei 7-190264, fuel having a large flow velocity collides in the direction perpendicular to the surface of the movable member. When foreign matter (hereinafter, "foreign matter" is referred to as contamination) is mixed, the surface of the movable member is worn. Particle size of about 2μ in contamination mixed in fuel
Those smaller than m can penetrate into the injector through fuel filters attached to the injector. Sand, which is a hard component among the contaminants, that is, a ceramic-based material, enters the inside of the injector and causes severe wear of the movable member. When the movable member wears, the non-movable member also wears due to contamination penetrating into the worn portion. In a fuel injection device disclosed in Japanese Patent Application No. Hei 7-190264, in which a fuel escape passage is provided in a contact area between a movable member and a non-movable member, the seat area is small. The amount of fuel leakage tends to increase due to wear, and as a result, the fuel injection characteristics change.

When steel is used for the movable member, the hardness of the high-speed tool steel having a relatively high hardness is Hv = 700-8.
Since the hardness of ceramic contamination is Hv
= 1000 to 2000, but the hardness is overwhelmingly low.
Therefore, the wear of the movable member due to the contamination of the ceramic system is increased, and the durability is reduced. When the wear of the movable member increases, the wear of the non-movable member also increases due to contamination penetrating into the wear portion of the movable member.

In the case of a movable member having a spherical member which is formed so that the seat portion with the non-movable member is flat and is rotatably supported, the spherical member is inclined by the inclination of the spherical member when the movable member is seated on the non-movable member. In some cases, the edge of the outer periphery of the flat portion may collide with the non-movable member earlier than the flat portion. Then
Extreme wear of the edge portion of the spherical member or the sheet portion of the non-movable member against which the edge portion collides reduces the sheet area and increases the sheet surface pressure. As the seat pressure increases, wear or breakage of the seat portion of the movable member or the seat portion of the non-movable member becomes more severe. When the movable member and the non-movable member are formed of a material having poor durability as described above, there is a problem that the amount of fuel leak increases remarkably during use, and the fuel injection characteristics are greatly changed.

Further, when a fuel release passage is provided in the non-movable member of the solenoid valve to reduce the area of the seat portion with the movable member, when the solenoid valve is closed, or when the movable member immediately before closing the valve has a low lift, There is a problem that the thin portion near the communication passage that can communicate the pressure control chamber and the low-pressure space is easily deformed by the fuel pressure inside the communication passage, and the reliability with respect to the breaking strength is low.

In the fuel injection devices disclosed in JP-A-5-99095 and JP-A-7-63135, at least one surface of a valve member for opening / closing an injection hole and a valve seat is provided with wear resistance. Further, it is intended to maintain the durability of the sheet portion by forming it from a non-conductive material having corrosion resistance or forming a high hardness material film having a predetermined hardness on at least one of the materials.

However, in the fuel injection device disclosed in JP-A-5-99095 and JP-A-7-63135, the valve member for opening and closing the injection hole and the valve seat are not in close contact with each other by flat surfaces, The contact between a spherical surface and a conical surface or between a conical surface and a conical surface. Therefore, it is more difficult to improve the processing accuracy of the sheet portion than in the case of performing flat processing.

Further, when a high-hardness material film having a predetermined hardness is formed on one or both of the movable member and the non-movable member of the solenoid valve, for example, the surface may be parallel to the deposition direction of the film. In addition, there is a problem that if there is a portion where the film thickness is uneven, the flow of the fuel is hindered, and the film is easily peeled off by the flow of the fuel. The present invention has been made to solve such a problem, and it is an object of the present invention to provide a fuel injection device that can reduce the amount of fuel leakage, can be reduced in size, is easy to process, and has high durability. .

[0014]

According to the fuel injection device of the present invention, the force that the movable member of the solenoid valve receives from the fuel in the pressure control chamber in the valve opening direction can be reduced.
Reliable sealing performance can be ensured without increasing the seat pressure. Therefore, the urging force for urging the movable member in the valve closing direction can be reduced, and the magnetic force of the electromagnetic valve that attracts the movable member against this urging force can be reduced.
By the above operation, the durability of the seat portion is improved and the solenoid portion of the solenoid valve can be downsized.

Further, when the sealing property of the high-pressure fuel when the solenoid valve is closed is improved, the leakage amount of the high-pressure fuel is reduced. Therefore, by employing the present invention, the load on the high-pressure pump for supplying the high-pressure fuel to the common rail is reduced. Since the driving torque can be reduced, the size of the high-pressure pump can be reduced. Further, by forming the seat portion of the movable member with a material having wear resistance, it is possible to reduce wear of the movable member due to collision with the flat valve seat. Further, even if a high-hardness ceramic-based contamination mixed in the fuel collides with the movable member, the wear amount of the movable member can be reduced. Therefore, it is possible to prevent an increase in the seat pressure due to a decrease in the seat area, thereby suppressing an increase in the amount of fuel leakage and maintaining the fuel injection characteristics with high accuracy.

As such a material having excellent wear resistance,
It is desirable to use a hard coating made of any one of TiN, CrN, and DLC (Dimond Like Carbon), or a ceramic or cemented carbide. According to the fuel injection device of the second aspect of the present invention, in addition to the movable member, the seat portion of the flat valve seat is formed of a material having wear resistance, thereby reducing wear of the flat valve seat due to collision with the movable member. it can. Further, wear of the flat valve seat due to contamination mixed in the fuel can be reduced.

According to the fuel injection device of the third aspect of the present invention, the force that the movable member of the solenoid valve receives from the fuel in the pressure control chamber in the valve opening direction can be reduced, and the seal can be surely secured without increasing the seat pressure. Nature can be secured. Therefore, the urging force for urging the movable member in the valve closing direction can be reduced, and the magnetic force of the electromagnetic valve that attracts the movable member against this urging force can be reduced. By the above operation, the durability of the seat portion is improved, and the solenoid portion of the solenoid valve can be downsized.

Further, when the sealing property of the high-pressure fuel when the solenoid valve is closed is improved, the amount of leakage of the high-pressure fuel is reduced. Therefore, by employing the present invention, the load on the high-pressure pump for supplying the high-pressure fuel to the common rail is reduced. Since the driving torque can be reduced, the size of the high-pressure pump can be reduced. Further, by forming the seat portion of the flat valve seat with the movable member using a material having wear resistance, the wear of the flat valve seat due to collision with the movable member can be reduced. Further, wear of the flat valve seat due to contamination mixed in the fuel can be reduced. Therefore, it is possible to prevent a decrease in the seat area and an increase in the seat pressure, thereby suppressing an increase in the amount of fuel leakage and maintaining the fuel injection characteristics with high accuracy.

According to the fuel injection device of the fourth aspect of the present invention, since the spherical member abutting on the flat valve seat is rotatably supported by the shaft member, the spherical member and the flat valve seat are moved by the movement of the spherical member. Are in good contact with each other on flat surfaces. further,
Since the seat portion of the spherical member is formed of a material having wear resistance, there is an effect that even when the outer periphery of the flat portion of the spherical member collides with the flat valve seat, the outer periphery of the flat portion of the spherical member is hardly worn.

According to the fuel injection device of the sixth aspect of the present invention, the force that the movable member of the solenoid valve receives from the fuel in the pressure control chamber in the valve opening direction can be reduced, and a reliable seal can be obtained without increasing the seat pressure. Nature can be secured. Therefore, the urging force for urging the movable member in the valve closing direction can be reduced, and the magnetic force of the electromagnetic valve that attracts the movable member against this urging force can be reduced. By the above operation, the durability of the seat portion is improved, and the solenoid portion of the solenoid valve can be downsized.

Further, when the sealing property of the high-pressure fuel when the solenoid valve is closed is improved, the leakage amount of the high-pressure fuel is reduced. Therefore, by employing the present invention, the load on the high-pressure pump for supplying the high-pressure fuel to the common rail is reduced. Since the driving torque can be reduced, the size of the high-pressure pump can be reduced. Further, by forming a film having wear resistance on at least one of the seats of the movable member and the flat valve seat, wear of the movable member or the flat valve seat due to collision between the movable member and the flat valve seat is reduced. it can. Furthermore, wear of the movable member or the flat valve seat due to contamination mixed in the fuel can be reduced. Therefore, it is possible to prevent a decrease in the seat area and an increase in the seat pressure, thereby suppressing an increase in the amount of fuel leakage and maintaining the fuel injection characteristics with high accuracy.

According to the fuel injection device of the present invention, the film formed on the sheet portion of the member having the fuel release passage and the film formed on the side wall forming the fuel release passage have substantially the same thickness. Since they are the same and are continuous, the flow of fuel near the side wall when the solenoid valve is opened is not hindered, and peeling of the film can be prevented. According to the fuel injection device of the eighth aspect of the present invention, the force that the movable member of the solenoid valve receives from the fuel in the pressure control chamber in the valve opening direction can be reduced, and the reliable sealing performance is ensured without increasing the seat pressure. it can. Therefore, the urging force for urging the movable member in the valve closing direction can be reduced, and the magnetic force of the electromagnetic valve that attracts the movable member against this urging force can be reduced. By the above operation, the durability of the seat portion is improved, and the solenoid portion of the solenoid valve can be downsized.

Further, when the sealing property of the high-pressure fuel when the solenoid valve is closed is improved, the leak amount of the high-pressure fuel is reduced. Therefore, by employing the present invention, the load on the high-pressure pump for supplying the high-pressure fuel to the common rail is reduced. Since the driving torque can be reduced, the size of the high-pressure pump can be reduced. In addition, the fuel release passage is formed in the flat valve seat, and a film is formed of a material harder than the flat valve seat between at least the communication passage and the fuel release passage of the flat valve seat, so that a thin portion near the communication passage is formed. The breaking strength against the fuel pressure inside the communication passage can be improved. Therefore, it is possible to suppress the thin portion in the vicinity of the communication passage from being deformed by the fuel pressure inside the communication passage, to improve the reliability with respect to the breaking strength, and to further ensure the sealing performance when the valve is closed. it can.

According to the fuel injection device of the ninth aspect of the present invention, the width of the upper surface in the radial direction near the communication passage of the flat valve seat is smaller than the depth of the fuel escape passage. The force that the movable member receives in the valve opening direction can be reduced. Therefore, the urging force for urging the movable member in the valve closing direction can be reduced, so that the magnetic force of the electromagnetic valve that attracts the movable member against this urging force can be reduced, and the solenoid portion of the electromagnetic valve is It can be relatively small.

[0025]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing a first embodiment of the present invention; (First Embodiment) FIGS. 1 to 4 show a fuel injection device according to a first embodiment of the present invention. The injector 1 shown in FIG.
High-pressure fuel of a constant pressure stored in a common rail (not shown) is supplied through a fuel filter 60 via a fuel pipe (not shown).

A needle valve 20 for opening and closing the injection hole 11a is accommodated in the nozzle body 11 of the injection nozzle 10 provided on the injection hole side of the injector 1 so as to be able to reciprocate.
The nozzle body 11 and the injector body 13 are connected by a retaining nut 14 with the packing tip 12 interposed therebetween. A pressure pin 21 is disposed on the side opposite to the injection hole of the needle valve 20, and a control piston 22 that is in contact with or is connected to the pressure pin 21 is disposed on the side opposite to the injection hole of the pressure pin 21. The needle valve 20, the pressure pin 21, and the control piston 22 constitute a "valve member" described in the claims. The pressure pin 21 is inserted through a spring 23, and the spring 23 urges the pressure pin 21 downward in FIG. 3, that is, in the injection hole closing direction. A pressure control chamber 61 is provided on the side opposite to the injection hole of the control piston 22.

Fuel filter 60 and injector body 1
The gap with the inner peripheral surface of No. 3 is set to about 25 μm,
By passing the fuel through this gap, contamination in the fuel is filtered. The high-pressure fuel introduced from the fuel filter 60 branches into a high-pressure fuel passage 62 and a high-pressure fuel passage 63. The high-pressure fuel branched into the high-pressure fuel passage 62 is supplied to the annular fuel reservoir 24 around the needle valve 20, and the high-pressure fuel branched into the high-pressure fuel passage 63 is supplied to the pressure control chamber 61. The pressure of the high-pressure fuel in the fuel reservoir 24 urges the needle valve 20 upward in FIG. 3, that is, in the lift direction in which the fuel reservoir 24 and the injection hole 11a communicate with each other, and the pressure control chamber 61
The pressure of the high pressure fuel in the lower part of FIG.
0 urges the control piston 22 in a direction to close the injection hole 11a.

As shown in FIG. 4, the high pressure fuel passage 63 and the pressure control chamber 61 are separated from the high pressure fuel passage 63 by the pressure control chamber 61.
A first throttle hole 65 as a first throttle portion that regulates the amount of fuel flowing into the tank is communicated. The flat plate 51 as the flat valve seat extends through the flat plate
A second throttle hole 66 is formed as a second throttle portion having a smaller passage resistance than the throttle hole 65 of FIG.

The low-pressure fuel passage 64 is a fuel passage for collecting leaked fuel from the sliding clearance between the control piston 22 and the needle valve 20, and communicates with the low-pressure fuel chamber 67. The low-pressure fuel passage 68 communicates with the low-pressure fuel chamber 67 and is a passage for discharging excess fuel in the injector to the outside. The low-pressure fuel passage 64, the low-pressure fuel chamber 67, and the low-pressure fuel passage 68 constitute a "low-pressure space" described in the claims.

The solenoid valve 30 is an electromagnetic two-way valve that connects and disconnects the pressure control chamber 61 and the low-pressure fuel chamber 67, and is disposed between the retaining nut 52 and the injector body 13. The electromagnetic coil 32 is wound around the core 31, and power is supplied from the connector 33. Movable member 40
Is composed of a shaft 41, a support member 42, a spherical member 43, and a push rod 44, and is supported by a cylinder 53 so as to be able to reciprocate. An armature 34 is fixed to the shaft 41 on the side of the electromagnetic coil 32. The shaft 41 and the support member 42 constitute a "shaft member" described in the claims. The lift amount of the movable member 40 is the spacer 5
4 can be adjusted by changing the axial length.

As shown in FIG. 1, a cylindrical support member 42 is fixed to the tip of the shaft 41 by press-fitting or welding. A clearance of several μm is formed between the support member 42 and the spherical member 43, and the spherical member 43 has a conical concave surface 4 formed at the tip of the shaft 41.
1a and the inner wall of the support member 42 are rotatably assembled. By caulking the tip of the support member 42, the spherical member 43 is prevented from dropping from the support member 42. The spherical member 43 has a structure in which a flat portion 43a is formed on a part of a ceramic or cemented carbide sphere.

A flat plate 51 is sandwiched between the cylinder 53 and the injector body 13. A second flat plate 51 axially penetrates the flat plate 51.
Are formed, and the pressure control chamber 61 and the low-pressure fuel chamber 67 can communicate with each other. The flat plate 51 shown in FIG. 4 omits an annular groove and the like described later. As shown in FIG. 2B, the flat plate 51 is formed by coating a surface of a base material 70 with a hard film 71.
For the base material 70, it is preferable to use a high-speed tool steel having a tempering temperature as high as 500 to 650 ° C., a high-temperature tempering die steel, or the like. TiN, CrN are applied to the sheet portion of the base material 70 with the spherical member 43.
, DLC, etc. coated with a hard coating 7
1 are formed. The hardness range of TiN, CrN and DLC is HV =
1000 to 3000. After processing the base material 70 into the shape shown in FIG. 2, it is a type of ion plating method in which a film material attached to the cathode is vaporized or ionized to form a film on the base material 70 using vacuum arc discharge. The hard coating 71 is formed by the AIP method.

The spherical member 43 can be made of steel coated with a hard film such as TiN, CrN, DLC or the like, and the flat plate 51 can be made of ceramic or cemented carbide. As shown in FIGS. 1 and 2, an annular seating surface 51 a is formed around the opening of the second throttle hole 66 in the sheet portion of the flat plate 51 with the spherical member 43. An annular groove is formed on the outer peripheral side of the annular seating surface 51a, and an annular groove passage 51b is formed by the annular groove. A cross-shaped groove is formed radially outward from the annular groove, and a fuel groove passage 51c is formed by the cross-shaped groove. Fuel groove passage 51c
Has one end communicating with the annular groove passage 51b and the other end of the fuel groove passage 51c communicating with the low-pressure fuel chamber 67. Annular groove passage 51
b and the fuel groove passage 51c constitute a "fuel release passage" described in the claims. Annular groove passage 51b
The fuel groove passage 51c is formed in the contact area between the spherical member 43 and the flat plate 51, and communicates with the low-pressure fuel chamber 67 even when the spherical member 43 is seated on the flat plate 51. The fan-shaped seating surface 51d is partitioned by the annular groove passage 51b and the fuel groove passage 51c.

The flat surfaces of the seat surface 51a and the seat surface 51d are set at the same height. When the electromagnetic two-way valve is closed, the contact between the spherical member 43 and the flat plate 51 is made with the annular groove interposed therebetween. And is performed on both the inner and outer seating surfaces.
The tapered surface 72 is formed so that the depth of the annular groove passage 51b gradually increases from the outer peripheral edge of the seat surface 51a toward the radial outside.
Are formed. This configuration is adopted for the following reason.

Since the pressure in the pressure control chamber 61 is higher than 100 MPa, a large force may be applied to the seating surface 51a near the second throttle hole 66, and may be elastically deformed. As in the first embodiment, the tapered surface 72 follows the outer peripheral edge of the seat surface 51a.
By increasing the radial thickness near the second throttle hole 66, deformation of the seating surface 51a can be suppressed, and the sealing performance when the valve is closed can be further ensured.

The flat portion 43a of the spherical member 43 has a seating surface 51a.
And a part of the seating surface 51d.
Is seated on the flat plate 51, the communication between the second throttle hole 66 and the annular groove passage 51b is cut off. Specific examples of the dimensions shown in FIG. 1 are shown below. The diameter D ₁ of the flat portion 43a = 1.
6 mm, the diameter D ₂ of the spherical member 43 = 2.0 mm, the diameter D _{3 of} the second throttle hole 66 = 0.35 mm, the inner diameter D _{4 of} the annular groove passage 51b = 0.5 mm, and the outer diameter D of the annular groove passage 51b. ₅ = 1.0
mm, and the diameter D ₆ of the control piston 22 is 4.5 mm. Also, the cutting allowance of the spherical member 43 = 0.4 mm, and the first aperture 6
5 = 0.25 mm, lift amount of the movable member 40 = 0.1
2 mm.

As a result of confirming the sealing performance with the configuration in which the tapered surface is not formed, in order to obtain good sealing performance until the fuel pressure in the pressure control chamber reaches about 150 MPa, the radial seating surface around the second throttle hole is required. The thickness must be about 0.2 mm or more.
If it is about 0.1 mm, the annular seating surface 5 as in this embodiment is used.
The shape in which the tapered surface 72 is provided from the outer peripheral edge of 1a is effective.

Next, the operation of the fuel injection device will be described. (1) When the power to the electromagnetic coil 32 is turned off, the push rod 44 is pressed downward in FIG. 3 by the urging force of the spring 45, and the spherical member 43 is seated on the flat plate 51. FIG.
The flat portion 43a of the spherical member 43 shown in FIG.
The communication between the pressure control chamber 61 and the low-pressure fuel chamber 67 is interrupted by contact with the seat surfaces 51a and 51d. The set load of the spring 45 is set to 65N, and the maximum pressure of the pressure control chamber 61 when using the injector is 1
Since the hydraulic load applied to the movable member 40 in the valve opening direction at 50 MPa is set to be larger than 21.1 N, the movable member 40 is turned off in the state where the coil 32 is de-energized.
But will not lift.

The pressure receiving area of the control piston 22 is larger than the pressure receiving area of the needle valve 20, and the urging force of the spring 23 acts in the injection hole closing direction. The sum of the force received in the closing direction and the urging force of the spring 23 is greater than the force received by the needle valve 20 in the lift direction from the fuel pressure in the fuel reservoir 24. Therefore, the pressure increasing speed of the high-pressure fuel passages 62 and 63 immediately after the start of the engine is about 25 to 30 MP.
Even in the state of about a / sec, the injection hole 11a is closed by the needle valve 20, and fuel injection is not performed.

(2) When the power supply to the electromagnetic coil 32 is turned on, the electromagnetic force for attracting the armature 34 generated in the coil 32 is set to about 100 N. Since the sum of the force applied to the movable member 40 in the valve opening direction is larger than the urging force of the spring 45, the movable member 40 is separated from the flat plate 51. When the spherical member 43 separates from the flat plate 51,
The second throttle hole 66 communicates with the low-pressure fuel chamber 67, and the pressure control chamber passes through the second throttle hole 66, the low-pressure fuel chamber 67, the low-pressure fuel passage 68, and the fuel recovery passage 55 a formed in the sealing member 55. The high-pressure fuel in 61 is discharged from the injector 1. Since the passage resistance of the second throttle hole 66 is smaller than the passage resistance of the first throttle hole 65, the pressure control is performed when the spherical member 43 separates from the flat plate 51 and the pressure control chamber 61 and the low-pressure fuel chamber 67 communicate with each other. The fuel pressure in the chamber 61 decreases. The fuel pressure in the pressure control chamber 61 decreases, and the sum of the force received by the control piston 22 in the injection hole closing direction and the urging force of the spring 23 from the fuel pressure in the pressure control chamber 61 is calculated from the fuel pressure in the fuel reservoir 24 by the needle valve. When the force applied to the needle valve 20 in the lift direction becomes smaller, the needle valve 20 lifts,
Fuel is injected from a.

Next, the difference between the operation and the effect of the fuel injection device depending on the presence or absence of the fuel escape passage will be described. FIG.
(A) shows the pressure distribution acting on the flat portion 43a of the spherical member 43 by the high-pressure fuel in the pressure control chamber 61, and shows the annular groove passage 51b and the fuel groove passage 51c.
7 schematically shows the difference in the distribution form as compared with the case where there is no. FIG. 5B shows the result of calculating the theoretical value of the pressure distribution with respect to the dimensions used in the first embodiment. Further, FIG. 6 shows values obtained by integrating the hydraulic load applied to the flat portion 43a in the valve opening direction when the pressure distribution of FIG. 5 is received in the entirety of the flat portion 43a.

When the solenoid valve 30 is closed to seal high-pressure fuel, the high-pressure fuel has a certain pressure distribution and the spherical member 4
3 and the flat plate 51 wrap around. First
In the embodiment, the annular groove passage 5 provided in the close contact plane is used.
Since the first groove 1b and the fuel groove passage 51c communicate with the low-pressure fuel chamber 67, the pressure of the annular groove passage 51b and the fuel groove passage 51c is reduced to the pressure in the low-pressure fuel chamber 67 (drain pressure ≒ 0). Therefore, as shown in FIG. 5, the pressure distribution from the second throttle hole 66 to the annular groove passage 51b is low.
A well-known pressure distribution represented by a gap flow between parallel disks connected by a G function is obtained.

On the other hand, in the case of a conventional injector in which the annular groove passage 51b and the fuel groove passage 51c communicating with the low-pressure fuel chamber 67 are not formed, the flat portion of the spherical member is indicated by a dotted line shown in FIG. Since the pressure in the close contact plane does not drop to the drain pressure up to the outer peripheral edge of the above, the pressure distribution has a long distribution in the radial direction. FIG. 6 shows that the oil pressure generated in the solenoid valve opening direction when there is a fuel release passage can be reduced by 70% or more as compared with the case where there is no fuel release passage. Therefore, the urging force of the spring 45 for urging the movable member 40 in the solenoid valve closing direction can be reduced, and the magnetic force of the electromagnetic coil 32 for lifting the movable member 40 against the urging force of the spring 45 can also be reduced. The size of the solenoid valve can be reduced. The above effects can also be obtained by reducing the diameter of either the flat portion 43a of the spherical member or the flat plate 51. However, if the seat area when the solenoid valve is closed is extremely reduced by reducing the diameter of either the flat portion 43a or the flat plate 51, the initial performance can be obtained because the seat pressure increases extremely. It is not suitable for practical use because of a problem in durability.

It is needless to say that the same effect can be obtained even when the distance between the spherical member 43 and the flat plate 51 is very small immediately before the solenoid valve is closed. Further, the annular groove passage 51 b and the fuel groove passage 51 c communicating with the low-pressure fuel chamber 67 are provided with the second throttle hole 6.
Since it is arranged at a point symmetrical position extending in a cross shape around the center 6, the pressure distribution acting on the plane portion 43a is also distributed symmetrically. That is, since a symmetrical pressure distribution can be obtained in the radial direction from the center of the flat portion 43a, inclination and eccentricity of the spherical member 43 hardly occur at the time of opening and closing the solenoid valve, and stable opening / closing valve control is possible. It has become.

Further, a spherical member 43 having a spherical convex surface is rotatably housed in a shaft 41 having a conical concave surface 41a, and a flat portion 43a of the spherical member 43 is
1, the axial displacement at the time of seating can be absorbed, the pressure control chamber 61 and the low pressure side can be reliably sealed by the spherical member 43, and the spherical member 43 is fluidized during the operation of the solenoid valve 30. It enables stable control without movement. Therefore, it is needless to say that this structure is not limited to the spherical member shown in the present embodiment, and that a good result can be obtained even when it is applied to, for example, the tip shape of a ball valve.

Next, the spherical member 43 and the flat plate 5
The effect of the first embodiment in which the sheet portion 1 is made of a material having excellent wear resistance will be described in comparison with a comparative example. In the comparative examples shown in FIGS. 7, 8 and 9, the spherical member 101 is formed of a steel ball for bearing (SUJ2), and the flat plate 110 is formed of high-speed tool steel (SKH2) or carbon tool steel (SK4F). . The hardness of the bearing steel ball, high-speed tool steel, and carbon tool steel is HV = 700 to 800, respectively. In the first embodiment, the spherical member 43 is formed of ceramic (Si ₃ N ₄ ), and the flat plate 51 is formed of a high-speed tool steel (SKH2) base material 70.
A hard film formed by coating TiN on the surface is used. The hardness of the hard coating 71 made of TiN is HV = 2200
2800.

Abrasion of the spherical member and the sheet portion of the flat plate occurs due to two factors: (1) collision between the spherical member and the flat plate, and (2) collision of contaminants mixed in the fuel. (1) When the movable member 100 is seated on the flat plate 110, if the center of the flat portion 101a of the spherical member 101 is shifted from the center of the second throttle hole 102, (A) in FIG. As shown in FIG. 1A, the spherical member 101 is inclined at the outer peripheral edge (hereinafter referred to as an edge) 101 of the flat plane portion 101a.
b easily collides with the flat portion 110a of the flat plate 110. As a result, as shown in FIG.
b wears out. Then, with respect to the seat diameter d ₁ before wear shown in (A) of FIG. 7, the seat diameter d ₂ after wear shown in FIG. 7 (B) is reduced.

The flat portion 110 of the flat plate 110
As shown in FIG. 8B, a is also worn by the collision of the edge 101b. Then, with respect to the seat diameter d ₁ shown in FIG. 8 (A) prior to wear, it is the seat diameter d ₃ after wear is reduced. As the sheet diameter decreases, the sheet area decreases and the sheet surface pressure increases.
01 and the sheet portion of the flat plate 110 accelerate at an accelerated rate. Further, the spherical member 101 and the sheet portion of the flat plate 110 are in a state of easily causing fatigue fracture due to an impact at the time of collision.

(2) Spherical member 101 and flat plate 1
10 also wears out due to contamination mixed in the fuel.
In a fuel tank of an automobile, there is a ceramic contamination represented by sand mixed in at the time of refueling or by removing a pipe connection. Their average hardness is very hard, about Hv = 1000-2000. Among these contaminants, those having a small particle diameter that can pass through a 25 μm gap of the fuel filter attached to the injector enter the inside of the injector. As shown in FIG.
When the contaminant collides with the high-pressure fuel against the spherical member 101 from the vertical direction, the flat portion 101a facing the second throttle hole 102 is severely worn as shown by a dotted line. When the flat portion 101a is worn, as shown in FIG. 9B, the contamination flows along with the fuel through the worn portion of the flat portion 101a, so that the spherical member 101 and the flat plate 1
10 wears further as indicated by the dotted line.

FIG. 10 shows the results of comparison of the wear amount δ between the spherical members of this embodiment and the comparative example. A described in FIG. 10, a comparative example with the present embodiment shows a case was operated 10 ⁷ times in air, shows the wear amount of the spherical member caused by the spherical member collides with the flat plate I have.
B is contamination (alumina Al ₂ O ₃ , particle size 0.39 μm)
Shows the amount of wear when the supply pressure of the fuel mixed with is set to 120 MPa and operated for 24 hours. The spherical members formed of the ceramic of the present embodiment are A and B
It can be seen that the wear amount is overwhelmingly smaller than that of the comparative example under either condition.

FIG. 11 shows changes in the amount of fuel leak and the amount of injection over time according to the present embodiment and the comparative example. Since there is a difference in processing dimensions between the present embodiment and the comparative example,
Although the amount of fuel leak and the amount of fuel injection before wear do not match, the difference between the amount of fuel leak and the amount of fuel injection over time can be seen. In the comparative example, the leak amount increased rapidly in 6 hours, but in the present example, it hardly increased even after 24 hours. Further, while the injection amount also increased in the comparative example, it hardly changed in the present embodiment. It can be seen that when the spherical member is worn, the sheet performance between the spherical member and the flat plate is significantly reduced, and the leak amount and the injection amount of the injector are increased. Thus, the durability of the sheet portion is significantly improved by forming the spherical member from ceramic.

FIG. 12 shows the difference in the amount of wear between the flat plate of the present embodiment and the flat plate of the comparative example. Figure 12 is a comparative example with the present embodiment shows the δ wear amount of the flat plate when operated ¹⁰⁷ times in the air. In this embodiment, the surface of the flat plate is formed with high hardness by applying a TiN coating to the high-speed tool steel, so that the edge of the spherical member is less likely to go around the flat plate.
Therefore, since the decrease in the seat area is small, the amount of fuel leakage can be reduced and the fuel injection characteristics can be controlled with high accuracy.

According to the first embodiment of the present invention, even when the solenoid valve is closed, or when the movable member is in a low lift state immediately before closing, the pressure distribution acting on the movable member 40 in the valve opening direction is reduced in the radial direction. Therefore, the attractive force of the electromagnetic coil 32 that lifts the movable member 40 against the urging force of the spring 45 is reduced, so that the electromagnetic coil 32 can be downsized. This is a fan-shaped seating surface 5 in addition to the seating surface 51a.
Since the movable member 40 is in close contact with a part of 1d, it can be realized without increasing the sheet surface pressure, so that it goes without saying that the durability is not impaired. Also, since the high-pressure fuel can be reliably sealed when the solenoid valve is closed, the amount of high-pressure fuel leakage can be reduced, and the load on the high-pressure pump for supplying high-pressure fuel to the common rail can be reduced. In addition, the driving torque of the high-pressure pump can be reduced, and the size of the high-pressure pump can be reduced.

Further, since the pressure distribution becomes equal in the radial direction with respect to the center axis of the spherical member 43, the spherical member 43 is less likely to be inclined or eccentric, and stable opening / closing valve control is possible. As a result, a uniform injection amount can be obtained, and stable injection amount control can be realized. In particular, it is possible to stably control the minute injection. Further, since the axis deviation when the spherical member is seated can be absorbed, the seat surface can be securely adhered, and the fuel leak amount when the spherical member is seated can be reduced to almost zero. Can be reduced.

Further, in the first embodiment, the annular groove passage 51b and the fuel groove passage 51d are formed in the contact area between the spherical member 43 and the flat plate 51, so that the spherical member 43 is formed.
And the plate area of the flat plate 51 is reduced. In such a configuration, the spherical member 43
The decrease in the sheet area due to the wear of the sheet portion between the plate and the flat plate 51 leads to an increase in the amount of fuel leakage, which is a factor for changing the fuel injection characteristics. However, the spherical member 43
Since the sheet portion of the plate and the flat plate 51 is formed of a material having excellent wear resistance, a decrease in the sheet area can be prevented, and the fuel injection characteristics can be maintained with high accuracy.

As described above, the fuel injection device according to the first embodiment can reduce the amount of fuel leakage from the solenoid valve by an inexpensive method and can reduce the size of the high-pressure pump that supplies high-pressure fuel to the common rail. It is possible to drive stable and stable fuel injection control with a small electromagnetic force. It also has high durability. (Second Embodiment) FIG. 13 shows a second embodiment of the present invention. In the second embodiment, the corners of the annular groove passages 51b of the flat plate 51 are formed at right angles, and the other configuration is the same as that of the first embodiment.

Since the corner of the annular groove passage 51b is formed at a right angle, the radial wall pressure near the second throttle hole 66 is reduced to the first wall.
It is smaller than in the embodiment. Therefore, in order to obtain a good sealing performance until the fuel pressure in the pressure control chamber is about 150 MPa, the thickness of the radial bearing surface 51a needs to be about 0.2 mm or more. Third Embodiment FIG. 14 shows a third embodiment of the present invention. Components substantially the same as those in the first embodiment are denoted by the same reference numerals.

In the third embodiment, five fuel passages 51c are provided radially at equal intervals around the second throttle hole 66 provided in the flat plate 80. This shows an embodiment for surely shortening the radial length of the pressure distribution generated in the movable member 40, and is particularly effective when controlling a high pressure of 150 MPa or more. That is, this is 15
This is a method of completely reducing the annular groove passage 51b to the drain pressure when controlling a high pressure of 0 MPa or more. However, the effect is greater as the number of fuel passages is larger, and is not limited to five.

In the first to third embodiments described above, since the support member and the shaft are formed separately,
The heat treatment step of the shaft becomes extremely easy. The shaft is heat-treated for the purpose of ensuring the durability of the guide portion (sliding portion) associated with the operation of the solenoid valve 30 and the durability of the high stress generating surface (contact surface) with the spherical member. For this reason, in the case where the tip of the shaft is caulked in the final step to prevent the spherical member from falling off as in the first embodiment, for example, after caulking an alloy steel to a material and performing a carburizing treatment on the tip, a carburizing heat treatment is performed. become. However, the diameter of the spherical member is
Since it is extremely small, such as φ2.0 mm shown in the first embodiment, the length of the carbon prevention treatment at the tip of the shaft is small, and this operation takes time. Therefore, in the first to third embodiments, the heat treatment of the shaft is facilitated by providing the cylindrical support member separately from the shaft. The shaft is subjected to a quenching process before the assembling process, and the heat treatment process can be performed very easily.

In the first to third embodiments, the support member is attached to the shaft by press-fitting or welding. However, in the present invention, the support member can be attached to the shaft by screw connection. (Fourth Embodiment) FIGS. 15 and 1 show a fourth embodiment of the present invention.
6 is shown. Components substantially the same as those in the first embodiment are denoted by the same reference numerals. In the first to third embodiments, the fuel release passage is provided on the flat plate side. In the fourth embodiment, the fuel release passage is provided on the spherical member side. In the spherical member 91 shown in FIG. 15, one of TiN, CrN, DLC and the like is coated on the sheet side of a base material made of high-speed tool steel, high-temperature returning die steel or the like to form a hard coating. The flat plate 96 shown in FIG. 16 is formed of ceramic or cemented carbide.

As shown in FIG. 15B, the shaft 9
Numeral 0 serves both as the shaft 41 and the support member 42 in the first embodiment. A circular contact surface 92 is formed at the center of the flat surface of the spherical member 91, and an annular annular groove passage 93 is formed around the contact surface 92. This annular groove passage 9
3, three fuel groove passages 94 are provided at equal intervals radially around the contact surface 92. The number of fuel groove passages radially formed in the spherical member is not limited to three. The fan-shaped seating surface 95 is surrounded by the annular groove passage 93 and the fuel groove passage 94.

As shown in FIGS. 16A and 16B, the plate plate 96 has only a second aperture 66 formed therein. In the fourth embodiment, the flat plate 96
Since only the second throttle hole 66 is formed in the first embodiment, since there is no thin portion near the fuel groove passage unlike the first to third embodiments, better sealing performance can be secured.

In each of the above-described embodiments of the present invention,
Although the spherical member and the sheet portion of the flat plate are both formed of a wear-resistant material, at least one of the spherical member and the flat plate may be formed of a wear-resistant material. It is possible to reduce abrasion in the seat portion with the plate and control the fuel injection characteristics with high accuracy.

(Fifth Embodiment) FIG. 1 shows a fifth embodiment of the present invention.
FIG. Components substantially the same as those in the first embodiment are denoted by the same reference numerals. In the fifth embodiment, a second throttle hole 66 that penetrates the flat plate 51 in the axial direction is formed in the flat plate 51 so that the pressure control chamber 61 and the low-pressure fuel chamber 67 can communicate with each other. A side wall 51e is provided between the bottom surface of the annular groove passage 51b of the flat plate 51 and the fan-shaped seating surface 51d.
Is provided. The seating surface 51a near the second throttle hole 66
And the fan-shaped seating surface 51d have the same plane height h, and the upper surface width w of the seating surface 51a is set smaller than the plane height h. A specific example of each dimension in FIG. 17B is a plane height h = 0.1 mm and an upper surface width w =
0.08 mm. Here, the second throttle hole 66 forms a “communication passage” described in the claims, and the plane height h corresponds to “depth of the fuel escape passage” described in the claims.

The flat plate 51 is made of TiN, CrN, DL on the surface of a base material 70 made of high-speed tool steel, high-temperature returning die steel, or the like.
One of C and the like is coated to form a hard film 71. The hardness range of the hard coating 71 is HV = 1000-
3000, and the hardness of the base material 70 is HV = 700-800.
It is about. This is a type of ion plating method in which a base material 70 is processed into a shape shown in FIG. 17, and then a film material attached to the cathode is vaporized or ionized to form a film on the base material 70 by using vacuum arc discharge. The hard coating 71 is formed by the AIP method. For this reason, the hard film 71 is formed to have a uniform thickness as compared with a film formed by, for example, vapor deposition, and particularly, the vicinity of the side wall 51e is continuously formed. Further, the breaking strength of the thin portion near the second throttle hole 66 and the seat surface 51a is improved.

In the fifth embodiment, since the hard coating 71 is formed to have a uniform thickness continuously, the flow of fuel near the side wall 51e when the solenoid valve is opened is not hindered. Peeling can be prevented. Further, at the time of closing the solenoid valve or at the time of low lift of the movable member immediately before closing, the thin portion near the second throttle hole 66 and the seat surface 51 a are deformed by the control chamber pressure inside the second throttle hole 66. Is suppressed by the hard coating 71, so that the second throttle hole 66
The reliability with respect to the breaking strength of the thin portion and the seating surface 51a in the vicinity can be improved, and the sealing performance at the time of closing the valve can be further ensured.

Further, since the upper surface width w of the seat surface 51a is set smaller than the plane height h, the movable member 40
The pressure distribution acting on the valve in the valve opening direction can be shortened in the radial direction. Therefore, the attraction force of the electromagnetic coil 32 that lifts the movable member 40 against the urging force of the spring 45 is reduced, so that the electromagnetic coil 32 can be made relatively small.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a main part of an electromagnetic valve in a pressure accumulating fuel injection device according to a first embodiment of the present invention.

FIG. 2 shows a flat plate of the first embodiment,
(A) shows a plan view, and (B) shows a cross-sectional view taken along line BB of (A).

FIG. 3 is a cross-sectional view illustrating a pressure accumulating fuel injection device according to a first embodiment.

FIG. 4 is a sectional view showing a main part of the pressure accumulating fuel injection device of the first embodiment.

5A and 5B show the pressure distribution of the seat portion in the solenoid valve of the first embodiment, FIG. 5A shows the positional relationship between the cross-sectional shape and the pressure distribution, and FIG. 5B shows the relationship between the radial distance of the seat portion and the pressure. FIG. 4 is a characteristic diagram illustrating a relationship.

FIG. 6 is a characteristic diagram showing a difference in hydraulic load between when there is a fuel release passage and when there is no fuel release passage.

FIG. 7A is a schematic cross-sectional view showing a rotating state of the spherical member in the first embodiment, and FIG. 7B is a schematic cross-sectional view showing wear of the outer peripheral edge of the spherical member.

FIG. 8A is a schematic sectional view showing a rotating state of a spherical member in the first embodiment, and FIG. 8B is a schematic sectional view showing a worn state of a flat plate.

FIG. 9A is a schematic cross-sectional view showing a state of wear of a spherical member due to contamination in fuel in the first embodiment;
(B) is a schematic sectional view showing wear of the spherical member and the flat plate.

FIG. 10 is a characteristic diagram showing a difference in wear depending on a material of a spherical member.

FIG. 11 is a characteristic diagram showing a change over time in an injection amount and a leak amount.

FIG. 12 is a characteristic diagram showing a difference in wear depending on a material of a flat plate.

13A and 13B show a flat plate according to a second embodiment, wherein FIG. 13A is a plan view and FIG. 13B is a cross-sectional view taken along line BB of FIG. 13A.

14A and 14B show a flat plate of a third embodiment, wherein FIG. 14A is a plan view and FIG. 14B is a cross-sectional view taken along line BB of FIG.

FIG. 15 shows a spherical member of a fourth embodiment,
(A) shows a side view and (B) shows a view in the direction of arrow B in (A).

16A and 16B show a flat plate of a fourth embodiment, wherein FIG. 16A is a plan view, and FIG. 16B is a sectional view taken along line BB of FIG.

17A and 17B show a flat plate of a fifth embodiment, wherein FIG. 17A is a plan view, and FIG. 17B is a sectional view taken along line BB of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Injector 10 Injection nozzle 11a Injection hole 20 Needle valve (valve member) 21 Pressure pin (valve member) 22 Control piston (valve member) 30 Solenoid valve 40 Movable member 41 Shaft (shaft member) 41a Conical concave surface 42 Support member (shaft) 43) Spherical member 43a Flat portion (seat portion) 51 Flat plate (flat valve seat) 51a, 51d Seat surface (seat portion) 51b Annular groove passage (fuel release passage) 51c Fuel groove passage (fuel release passage) 51e Side wall 62 , 63 High-pressure fuel passage 64, 68 Low-pressure fuel passage 65 First throttle hole 66 Second throttle hole (communication passage) 67 Low-pressure fuel chamber 70 Base material 71 Hard coating 80 Flat plate (flat valve seat) 91 Spherical member 96 Flat plate Plate (flat valve seat)

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI F02M 51/06 F02M 51/06 Z F16K 1/14 F16K 1/14 A 25/04 25/04 31/06 305 31/06 305L 305M 385 385A

Claims (9)

[Claims] 1. An accumulator type fuel injection device for injecting high pressure fuel accumulated in a common rail from an injection nozzle of an injector to an internal combustion engine, comprising a high pressure fuel passage capable of supplying high pressure fuel to an injection hole of the injection nozzle, and the injection. A valve member intermittently communicating with the hole, a pressure control chamber provided on the opposite side of the valve member from the injection hole, and a pressure control chamber for urging the valve member in the injection hole blocking direction by fuel pressure supplied from the high pressure fuel passage; An electromagnetic valve for intermittently interposing a passage or a low-pressure space formed of a low-pressure fuel chamber, wherein the electromagnetic valve is a planar valve seat formed around a communication passage capable of communicating the pressure control chamber and the low-pressure space; and A movable member that closes communication between the pressure control chamber and the low-pressure space by closely contacting the flat valve seats with each other on a flat surface, and communicates with the low-pressure space in a contact region between the movable member and the flat valve seat; A fuel escape passage formed in one of the movable member and the flat valve seat, wherein at least a seat portion of the movable member with the flat valve seat is formed of a material having wear resistance. Type fuel injection device. 2. The accumulator type fuel injection device according to claim 1, wherein at least a seat portion of said flat valve seat with said movable member is formed of a material having wear resistance. 3. A pressure accumulating fuel injection device for injecting high pressure fuel accumulated in a common rail from an injection nozzle of an injector to an internal combustion engine, wherein the high pressure fuel passage is capable of supplying high pressure fuel to an injection hole of the injection nozzle. A valve member intermittently communicating with the hole, a pressure control chamber provided on the opposite side of the valve member from the injection hole, and a pressure control chamber for urging the valve member in the injection hole blocking direction by fuel pressure supplied from the high pressure fuel passage; An electromagnetic valve for intermittently interposing a passage or a low-pressure space formed of a low-pressure fuel chamber, wherein the electromagnetic valve is a planar valve seat formed around a communication passage capable of communicating the pressure control chamber and the low-pressure space; and A movable member that closes communication between the pressure control chamber and the low-pressure space by closely contacting the flat valve seats with each other on a flat surface, and communicates with the low-pressure space in a contact region between the movable member and the flat valve seat; A fuel escape passage formed in one of the movable member and the flat valve seat, wherein at least a seat portion of the flat valve seat with the movable member is formed of a material having wear resistance. Type fuel injection device. 4. The movable member includes a shaft member and a spherical member rotatably supported by the shaft member, wherein the spherical member has a flat portion in close contact with the flat valve seat in a plane and the shaft. 4. The accumulator type fuel injection device according to claim 1, further comprising a spherical convex portion sliding with a member. 5. The material having wear resistance is TiN, Cr.
The accumulator type fuel injection device according to any one of claims 1 to 4, wherein the fuel injection device is a hard coating made of any one of N and DLC, or a ceramic or cemented carbide. 6. A pressure-accumulation type fuel injection device for injecting high-pressure fuel accumulated in a common rail from an injection nozzle of an injector to an internal combustion engine, comprising a high-pressure fuel passage capable of supplying high-pressure fuel to an injection hole of the injection nozzle, and the fuel injection device. A valve member intermittently communicating with the hole, a pressure control chamber provided on the opposite side of the valve member from the injection hole, and a pressure control chamber for urging the valve member in the injection hole blocking direction by fuel pressure supplied from the high pressure fuel passage; An electromagnetic valve for intermittently interposing a passage or a low-pressure space formed of a low-pressure fuel chamber, wherein the electromagnetic valve is a planar valve seat formed around a communication passage capable of communicating the pressure control chamber and the low-pressure space; and A movable member that closes communication between the pressure control chamber and the low-pressure space by closely contacting the flat valve seats with each other on a flat surface, and communicates with the low-pressure space in a contact region between the movable member and the flat valve seat; A fuel release passage formed in one of the movable member and the flat valve seat, and forming a wear-resistant coating on at least one of the seats of the movable member and the flat valve seat. A pressure accumulating fuel injection device. 7. A film having wear resistance is formed on a seat portion of a member having the fuel escape passage and a side wall forming the fuel escape passage, and is formed on a seat portion of the member having the fuel escape passage. 7. The accumulator type fuel injection device according to claim 6, wherein the film formed on the side wall and the film formed on the side wall have substantially the same thickness and are continuous. 8. A pressure-accumulation type fuel injection device for injecting high-pressure fuel accumulated in a common rail from an injection nozzle of an injector to an internal combustion engine, comprising: a high-pressure fuel passage capable of supplying high-pressure fuel to an injection hole of the injection nozzle; A valve member intermittently communicating with the hole, a pressure control chamber provided on the opposite side of the valve member from the injection hole, and a pressure control chamber for urging the valve member in the injection hole blocking direction by fuel pressure supplied from the high pressure fuel passage; An electromagnetic valve for intermittently interposing a passage or a low-pressure space formed of a low-pressure fuel chamber, wherein the electromagnetic valve is a planar valve seat formed around a communication passage capable of communicating the pressure control chamber and the low-pressure space; and A movable member that closes communication between the pressure control chamber and the low-pressure space by closely contacting the flat valve seats with each other on a flat surface, and communicates with the low-pressure space in a contact region between the movable member and the flat valve seat; A fuel release passage formed in the flat valve seat, and a harder than the flat valve seat between the fuel release passage and a communication passage that can communicate at least the pressure control chamber and the low-pressure space of the flat valve seat. An accumulator type fuel injection device characterized in that a film is formed of a material. 9. The accumulator type fuel injection device according to claim 8, wherein a radial upper surface width of the flat valve seat near the communication passage is smaller than a depth of the fuel escape passage.