JPH08326632A - Fuel injection device - Google Patents

Abstract

PURPOSE: To improve the workability related to the assembly and disassembly of a housing and a valve advance restricting member to simplify the regulating work. CONSTITUTION: The fuel injection device is provided with a housing 20 into which a valve drive mechanism for advancing and retracting a valve 10, and a valve advance restricting member 23 mounted to the housing 20 to limit advance of the valve 10. A screw fastening means 100 for connecting the housing 20 and the valve advance restricting member 23 so that they can be disassembled, is provided. Simply by releasing fastening of the screw fastening means 100, the housing 20 and the valve advance restricting member 23 can be disassembled.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel injection device mainly used in a vehicle internal combustion engine (also called an engine).

[0002]

2. Description of the Related Art A fuel injection device having a spark plug integrated with a fuel injection valve for directly injecting fuel into a combustion chamber of an engine and an ignition plug integrally formed with the fuel injection valve. There is (for example, the actual exploitation Sho 63-1547
No. 60). In this type of fuel injection device, a cross-sectional view of FIG. 3 and a conventional example of the present invention will be described.
This will be described with reference to an enlarged view of the relevant part. Note that hatching showing a cross section is omitted in FIG. The fuel injection device shown in FIG. 3 is roughly divided into a housing sub-assembly (corresponding to a housing in the present invention and also simply referred to as a housing) 20, a body sub-assembly 21 attached to the housing sub-assembly 20, It is composed of a valve sub-assembly 4 and a cap sub-assembly 23.

The housing sub-assembly 20 has an inner cylindrical body 34 and an outer cylindrical body 35 which have a substantially hollow cylindrical shape and which are double-inserted inside and outside. The inner cylinder 34 is made of SUS304 material, and the outer cylinder 35 is made of SUS magnetic material. The joint surface between the inner cylindrical body 34 and the outer cylindrical body 35 is axially communicated by mutual insertion and both ends in the axial direction (upper and lower ends in the drawing).
Is formed to open the fuel passage 33. Further, the outer tubular body 35 is provided with a flange member 60 at the upper end thereof.

In the annular space formed around the inner cylinder 34 by the flange member 60 of the outer cylinder 35, SUS is formed.
A ring-shaped joint part 37 made of a material is rotatably fitted in a state in which a gap is maintained between the lower surface thereof and the bottom surface of the annular space portion. The joint part 37 is attached to the inner cylindrical body 34 by SU.
It is fixed by tightening the fixing nut 38 made of S303 material. The joint component 37 is formed with a fuel intake port 1 having one end opening to the outer side surface and the other end opening to the lower surface. A strainer 39 is incorporated in the fuel intake port 1, and a fuel supply pipe is connected to the opening on the outer side surface thereof. In addition, between the inner cylindrical body 34 and the joint component 37,
An O-ring (reference numeral omitted) is used to seal between the outer cylinder 35 and the joint component 37.

The body sub-assembly 21 incorporated by being inserted into the housing sub-assembly 20 comprises a second block 15 made of a ring-shaped SUS304 material, and a substantially hollow cylindrical shape in which the second block 15 is insert-molded in the central portion. Insulating cylinder 41 made of an electric insulating material such as polyphenylene sulfide resin (also referred to as PPS resin)
, A core 2 made of a substantially hollow cylindrical magnetic material fitted in the insulating cylinder 41, a bobbin 16 made of an electrically insulating material such as PPS resin fitted in the core 2, and the bobbin 1
A coil 42 wound in a multi-layered structure on the No. 6 and a ring-shaped SUS304 material fitted to the lower end of the core 2
The block 14 and the block 14 are fitted in a yoke 17 made of a substantially hollow cylindrical SUS magnetic material. The insulating cylinder 41 and the core 2, the core 2 and the first block 14, and the first block 14 and the yoke 17 are sealed by O-rings (reference numerals omitted). The second
The upper end of the block 15 is fitted in the inner cylindrical body 34, and an O-ring (reference numeral omitted) between the both 15 and 34 is sealed.

An appropriate number of grooves 17a are provided on the outer peripheral surface of the yoke 17 along the axial direction. This groove 17
The opening a is formed in the upper end surface of the yoke 17, and the lower end thereof is connected to a communication hole 44 penetrating the yoke 17 in the radial direction. Further, the fuel passage formed by the groove 17 a and the outer cylindrical body 35 communicates with the fuel passage 33. A harness 43 is electrically connected to the coil 42 by soldering. The harness 43 is pulled out upward through the inside of the housing sub-assembly 20. The lead-out end of the harness 43 is electrically connected to an electronic control unit (also referred to as an ECU) not shown, and the coil 42 receives an input from the electronic control unit to energize or deenergize the coil. The harness 43 is wound with a shield material 59 made of a material having excellent conductivity, such as copper foil or aluminum foil.

A set screw 8 made of SUS303 material is inserted in the insulating cylinder 41. The head of the set screw 8 is screwed onto the insulating cylinder 41,
An O-ring (reference numeral omitted) between the shaft and the insulating cylinder 41.
Is sealed by. Further, a set screw stopper (referred to as a screw stopper) made of SUS303 material for fixing the set screw 8 is provided in the insulating cylinder 41.
7 is screwed. The socket 7a of the screw stopper 7 has a connection terminal 6a for the high tension cord 6.
Are electrically connected. In addition, the high tension cord 6 and the insulating cylinder 4 in the housing sub-assembly 20.
It is assumed that the space portion around 1 (denoted by reference numeral 47) is filled with an insulating filler such as an epoxy resin (not shown).

The valve sub-assembly 4 incorporated in the lower portion of the body sub-assembly 21 is a shaft-shaped valve 10 made of SUS440C material, and a valve support made of an electric insulating material such as PPS resin in which the upper end of the valve 10 is insert-molded. 48 and the armature 3 made of a magnetic material insert-molded on the outer peripheral portion of the valve support 48. The valve support 48 has a cylindrical portion in its upper half.

The valve sub-assembly 4 is inserted in the body sub-assembly 21 so as to be able to move back and forth (movement up and down in the drawing). Specifically, after inserting the valve spring 9 made of SUS304 material into the insulating cylinder 41, the cylindrical portion of the valve support 48 into which the lower end portion of the valve spring 9 is fitted is fitted in the insulating cylinder 41. . When the valve spring 9 is fitted into the valve support 48, the lower end surface of the spring 9 comes into contact with the upper end surface of the valve 10 to establish electrical continuity. Further, a pipe 61 made of SUS303 material is rotatably interposed between the set screw 8 and the valve spring 9. The pipe 61 prevents twisting due to the rotation of the valve spring 9 when the set screw 8 is screwed. The body sub-assembly 2 built in the housing sub-assembly 20.
The valve drive mechanism for moving the valve 10 forward and backward is constituted by 1 and the valve spring 9.

As shown in FIG. 4, the cap sub-assembly 23 incorporated in the lower end portion of the housing sub-assembly 20 is made of a stainless alloy material which has a substantially hollow cylindrical shape and has a nozzle 5a at its lower end. A valve seat 5, a ceramic insulating cover 13 having a substantially hollow cylindrical shape and having the valve seat 5 screwed therein, and a SUS system having a substantially hollow cylindrical shape and having the insulating cover 13 inserted therein. Material cap 11
Consists of The valve seat 5 and the cap 11 are insulated by an insulating cover 13.

The lower end of the cap 11 is made of a Ni alloy material and has a lower end edge 5b of the valve seat 5.
A ground electrode (also referred to as a GND electrode) 12 that is directed to the is provided. Further, the cap 11 has a male screw 11a for screwing onto a cylinder head (not shown) of an internal combustion engine.
Are formed. The valve seat 5 and the insulating cover 1
3, the insulating cover 13 and the cap 11 are sealed by O-rings and gaskets (both not shown).

The cap sub-assembly 23 is incorporated in the housing sub-assembly 20, and more specifically, the valve 10 is inserted into the valve seat 5 so that the valve 10 can be moved back and forth, that is, slidably, and the cap 11 can be attached to the housing sub-assembly 20. It is fitted to the lower end of the outer tubular body 35 and fixed by welding such as laser welding (the reference numeral W is attached to the welded portion in FIG. 4) over the entire circumference.
The valve sub-assembly 4 is normally urged forward (downward in the drawing) by the elasticity of the valve spring 9, whereby the valve 10 is held in the closed state. In this valve closed state, the forward end of the valve 10 is restricted by the front end (lower end in the figure) of the valve 10 coming into contact with the seat surface of the valve seat 5. The valve sub-assembly 4 including the valve seat 5 corresponds to the valve advancement restriction member in the present invention.

A cylindrical ring tube 18A made of metal, for example, SUS303 material is inserted into the cap 11 and faces the yoke 17. This ring cylinder 18A
A ring-shaped plate thickness adjusting plate 22A made of metal, for example, SUS440C-based material is interposed between the yoke 17 and the yoke 17 opposed thereto. This plate thickness adjustment plate 2
The opening / closing stroke of the valve 10 is finely adjusted by adjusting the plate thickness of 2A. A fuel passage is formed between the insulating cover 13 and the valve support 48 so as to communicate with the valve seat 5 through the communication hole 44 of the yoke 17.

First, the operation of the fuel injection valve in the fuel injection device will be described. The fuel supplied from a fuel tank (not shown) in a state where a predetermined pressure is applied is filtered by the strainer 39 of the fuel inlet 1 and then reaches the inside of the valve seat 5 through the fuel passage. However, since the valve 10 is held in the closed state by the elasticity of the valve spring 9, the injection port 5a of the valve seat 5 is
No fuel injection from

When the coil 42 is energized by the input of an electric signal from the electronic control unit, the suction force of the core 2 acting on the armature 3 causes the valve sub-assembly 4 to retract and the valve 10 to open. Fuel is injected from the injection port 5a of the valve seat 5. Then, when the electric signal to the coil 42 is turned off and the attraction force of the core 2 acting on the armature 3 is released, the valve 10 is held in the closed state again by the elasticity of the valve spring 9, so that the valve seat is closed. Fuel injection from the injection port 5a of No. 5 is stopped.

Next, the operation of the spark plug will be described. The high voltage from the ignition coil is transmitted to the valve seat 5 via the high tension cord 6, the screw stopper 7, the set screw 8, the pipe 61, the valve spring 9 and the valve 10, and the edge portion 5b of the valve seat 5 is used as a central electrode. A spark is generated between the ground electrode 12 and the ground electrode 12 facing it to ignite the air-fuel mixture in the combustion chamber. A fuel injection device having a structure similar to the above is disclosed in, for example, Japanese Patent Application No. 7-544 previously proposed by the same applicant.
No. 66 (unpublished at the time of this application).

[0017]

In the above fuel injection device, the housing sub-assembly (housing) 2 is used.
0 and cap sub-assy (valve advance restriction member) 23
And are joined by welding. Therefore, after welding, if the opening / closing stroke of the valve 10 (also referred to as valve stroke), the flow rate and spray performance, the sealing performance by welding (also referred to as oil tightness), etc. are confirmed and the required performance is not satisfied,
It is necessary to remove the welded portion (see reference numeral W in FIG. 4), disassemble and re-weld. Therefore, there is a problem in that workability relating to assembly and disassembly is low, and it is difficult to achieve required performance, that is, adjustment work is difficult.

In addition, for example, Japanese Patent Application No. 6-65039 (unpublished at the time of filing this application), which was previously proposed by the same applicant, corresponds to a housing in a fuel injection device having no spark plug, that is, a fuel injection valve. A configuration is disclosed in which a valve seat corresponding to a valve advancement restricting member is joined to a tubular cover by welding. Also in this case, the same problem as described above occurs.

The technical problem to be solved by the present invention is as follows.
An object of the present invention is to provide a fuel injection device capable of improving workability in assembling and disassembling a housing and a valve advancement restricting member and performing an adjusting operation easily.

[0020]

According to the invention of claim 1, which solves the above-mentioned problems, a housing (20) containing a valve drive mechanism for advancing and retracting a valve (10) and attached to the housing (20). Being said valve (10)
In a fuel injection device including a valve advancement restricting member (23) for restricting the advancement of a valve, a screw fastening means (100) for disassemblingly connecting the housing (20) and the valve advancement restricting member (23) is provided. It is a fuel injection device.
The invention according to claim 2 is the fuel injection device according to claim 1, wherein the screw fastening means (100) is a union joint.

[0021]

According to the fuel injection device of the first aspect, the housing (20) and the valve advancement restricting member (23) are connected by the screw fastening means (100). Therefore, the housing (20) and the valve advancement restricting member (23) can be disassembled by releasing the fastening of the screw fastening means (100). According to the fuel injection device of the second aspect, since the screw fastening means (100) is a union joint, the screw fastening work and its releasing work can be easily performed.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A fuel injection device according to an embodiment of the present invention will be described with reference to the sectional view of FIG. 1 and the enlarged view of the main part of FIG.
In FIG. 1, hatching showing a cross section is omitted. Further, since this embodiment is a modification of a part of the conventional example (see FIGS. 3 and 4), only the modified part will be described in detail, and the same or substantially the same parts will be denoted by the same reference numerals. The overlapping description will be omitted. FIG.
In, housing sub-assembly (housing) 20
The cap sub-assembly (valve advancing restriction member) 23 is connected by a union joint 100 instead of welding in the conventional example. The union joint 100 corresponds to the screw fastening means in the present invention.

The union joint 100, as shown in detail in FIG. 2, has a union threaded portion 101 formed on the outer peripheral surface of the lower end portion of the outer tubular body 35 of the housing sub-assembly 20, and is screwed into this union threaded portion 101. The union nut 103 is provided. Union nut 1
03 is made of the same material as the outer cylindrical body 35,
The cap sub-assembly 23 has a flange portion 104 that contacts the stepped portion on the outer peripheral surface of the cap 11 as a union flange portion 102. Further, an O-ring 62 for ensuring oil tightness between the fitting surfaces is provided on the fitting surface of the cap 11 with the outer cylindrical body 35.

In the fuel injection device, the housing sub-assembly 20 and the cap sub-assembly 23 are assembled as follows. That is, by fitting the cap sub-assembly 23 to the housing sub-assembly 20 and then tightening the union nut 103 to the union screw portion 101 of the housing sub-assembly 20, the flange portion 104 of the union nut 103 is fixed to the cap sub-assembly 23. The housing sub-assembly 20 and the cap sub-assembly 23 are joined to each other in contact with the union flange 102.

Therefore, if the required performance is not satisfied by checking the valve stroke, flow rate and spray performance of the valve 10, oil tightness by welding, etc. after the above-mentioned connection, the union nut 103 is attached to the union of the housing sub-assembly 20. The housing sub-assembly 20 and the cap sub-assembly 23 can be disassembled by removing from the screw portion 101. After adjusting the required performance, the cap subassembly 2 is again attached to the housing subassembly 20 in the same manner as above.
After fitting 3, the union nut 103 is fastened to the union screw portion 101 of the housing sub-assembly 20, so that the housing sub-assembly 20 and the cap sub-assembly 23 can be coupled.

According to the above-described fuel injection device, the housing sub-assembly 20 and the cap sub-assembly 23 are connected by the union joint 100 which is a screw fastening means. Therefore, assembling and disassembling work as compared with the conventional welding connection. The property is improved, and the adjustment work can be easily performed. Further, since the screw fastening means is the union joint 100, the screw fastening work and its releasing work can be easily performed, and the adjustment work can be performed more easily.

As the screw fastening means, in addition to the union joint 100 of the embodiment, a flange type joint using bolts and nuts, bolting, screwing with male and female threads, and the like may be adopted. Further, in addition to the fuel injection device of the above embodiment, also in the fuel injection device having no spark plug, for example, in the fuel injection valve of Japanese Patent Application No. 6-65039 described above, it corresponds to the tubular cover corresponding to the housing and the valve advancement restricting member. The same effect as that of the embodiment can be obtained by connecting the valve seat with the union joint 100.

[0028]

According to the fuel injection device of claim 1,
Since the housing and the valve advancement restricting member are connected by the screw fastening means, workability relating to the assembling and disassembling thereof is improved as compared with the conventional welding, and the adjustment work can be performed easily. According to the fuel injection device of the second aspect, since the screw fastening means is the union joint, the screw fastening work and the releasing work thereof can be easily performed, and the adjustment work can be performed more easily.

[Brief description of drawings]

FIG. 1 is a sectional view showing a fuel injection device according to an embodiment of the present invention.

FIG. 2 is an enlarged view of a main part of FIG.

FIG. 3 is a cross-sectional view showing a conventional fuel injection device.

FIG. 4 is an enlarged view of a main part of FIG. 3;

[Explanation of symbols]

 10 Valve 20 Housing Sub Assembly (Housing) 23 Cap Sub Assembly (Valve Advance Restricting Member) 100 Union Joint (Screw Fastening Means) 103 Union Nut

Claims (2)

[Claims] 1. A fuel injection device comprising a housing containing a valve drive mechanism for advancing and retreating a valve, and a valve advancing restriction member attached to the housing for restricting advancing of the valve, the housing and the valve. A fuel injection device, characterized in that a screw fastening means is provided for removably connecting the advancement restriction member. 2. The fuel injection device according to claim 1, wherein the screw fastening means is a union joint.