JPH03210059A - Fuel injection valve - Google Patents

Abstract

PURPOSE:To obtain a fuel injection valve with extremely high productivity without requiring high-precision machining and complex alignment by forming at least one of the upper end section of an armature and the end section of the stopper section of a stator into a partial spherical shape. CONSTITUTION:The upper end section 9a of an armature 9 is formed into a partial spherical shape, even if the inclined armature 9 collides with the lower end section 8c of a stopper section 8b, the collision condition, e.g., collision pressure, is invariably kept constant. It is not required to form a high-precision gap between the armature 9 and the guide hole 4b of an armature guide 4 or to machine the stopper section 8b of a stator with high precision, a ball valve 11 is rarely rebounded when the armature 9 collides with the stopper section, 8b, its action is stabilized, and no twist occurs.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a fuel injection valve used in an internal combustion engine.

[Prior Art] Conventionally, as a fuel injection valve used in an internal combustion engine, there is one shown in FIG. 6, for example. This fuel injection valve 100
There is a clearance of several μm between the outer diameter of the needle valve 101 and the inner diameter of the body 102, and the needle valve 101 slides on the body 102 through this clearance. Further, the amount of movement of the needle valve 101 is restricted by abutment between the flange portion 103 of the needle valve 101 and the spacer 104.

In such a configuration, a clearance of several μm is required for a two-dollar valve 10.
1 and the body 102 by selective fitting.

In addition, the seat surfaces of the needle valve 101 and the body 102 are assembled with extremely high coaxiality with respect to their respective sliding diameters,
Also, their roundness is manufactured with high accuracy. Furthermore, the air gap G between the core 105 and the connector 106 is adjusted by selecting the spacer 104, which is extremely troublesome. Note that 107 is a return spring, and 108 is a spring receiver.

[Problems to be Solved by the Invention] Therefore, conventional fuel injection valves require highly accurate machining and complicated adjustment, and have the drawback of low productivity. Note that Japanese Patent Application Laid-Open No. 199965/1984 is a prior art document related to the present application.

An object of the present invention is to provide a fuel injection valve that does not require highly accurate machining or complicated adjustment and has extremely high productivity.

[Technical means for solving the problems] In order to solve the above problems, the present invention includes a stator incorporating an electromagnetic coil, an armature guide having a guide hole in the center, a fuel injection hole, and a conical shape communicating with the stator. A valve body with a valve seat portion is arranged in the cylindrical case body in the order listed from the upstream side to the downstream side of the case body, and a rod-shaped armature moves in the axial direction in the guide hole of the armature guide. A ball valve is attached to the downstream end of the armature, which comes into contact with and leaves the valve seat of the valve body as the armature moves in the axial direction, and the upstream end of the armature contacts the stator by moving the armature in the axial direction. In the fuel injection valve, the armature contacts and separates from the end of a stopper provided at the center of the armature, and movement of the armature in the axial direction is performed by supplying and interrupting current to the electromagnetic coil and the elastic force of the elastic member. At least one of the upstream end of the armature and the end of the stopper portion of the stator has a partially spherical configuration.

[Function] At least one of the upstream end of the armature and the end of the stopper portion of the stator opposite to the upstream end is formed into a partially spherical shape, so that the armature moves toward the armature guide by supplying or cutting off current to the electromagnetic coil. When the armature is guided by the guide hole and moves in its axial direction, even if it comes into contact with the end of the stopper part, the armature does not bounce or twist inside the valve body. Therefore, the fuel injection valve always operates stably.

E Example J This invention will be explained below with reference to drawings showing examples. 1st
Figures 1 to 3 show the first embodiment. In the figure, a fuel injection valve 1 has an armature guide 4 made of a magnetic material, a valve body 3 made of a hard metal such as 5US4400 on the downstream side (lower side in Fig. 1) of the armature guide 4, and an end made of a metal such as aluminum. It is housed in a bent cylindrical case body 2 and integrally connected to the case body 2. A guide hole 4b is provided in the center of the armature guide 4, and a rod-shaped armature 9 is loosely inserted into this guide hole 4b.

Inside the case body 2, a stator 8 made of a soft magnetic material is disposed and has a fuel notch 8a on the upstream side (upper side in FIG. 1) of the armature guide 4. When an electrical signal is applied from the computer 7 via the terminal 6, an electromagnetic force is generated. This electromagnetic force generates an attractive force between the stator 8 and the armature 9, and the armature 9 is lifted upward in FIG. It abuts against the lower end surface of the rod-shaped stopper portion 8b. 5US440C at the lower end of armature 9
A ball valve 11 made of hard metal such as the above is integrally joined by laser welding.

Therefore, the ball valve 11 moves integrally with the armature 9.

On the other hand, fuel pumped from the fuel tank 12 by the electromagnetic pump 13 passes through the filter 14 and is sent to the main fuel injection valve 1 and the pressure control valve 15. The pressure control valve 15 keeps the fuel pressure in the fuel passage from the electromagnetic pump 13 to the pressure control valve 15 constant.

As a result, fuel at a constant pressure regulated by the pressure control valve 15 is fed into the fuel injection valve 1 .

The fuel at a constant pressure applied to the fuel injection valve 1 passes from the inside of the case body 2 through the fuel notch 8a of the stator 8 via the joint 2a at the upper end of the case body 2 and the filter 17, and the outer circumference of the electromagnetic coil 5. The fuel is supplied to the fuel reservoir 18 through a fuel hole 4a formed in the armature guide 4.

A conical valve seat portion 19 that expands linearly toward the upstream side is formed on the inner wall of the valve body 3.
communicates with a fuel injection hole 3b formed in the lower end of the valve body 3. When the ball valve 11 comes into contact with the valve seat 19, it closes the fuel injection hole 3b.

On the other hand, in FIG. 1, the upper end portion 98 of the rod-shaped armature 9 (ie, the end portion on the opposite side from the ball valve 11) is formed into a partially spherical shape. The upper end 9a and outer circumferential surface 9b of the armature 9, the lower end surface of the stopper portion 8b of the stator 8 (the surface facing the upper end 9a of the armature 9>8G, and the inner circumferential surface 4C of the guide hole 4b of the armature guide 4 are made of a hard material. Chrome plating is applied to form a solid gap between each to ensure wear resistance.
A longitudinal sectional front view of another part of the figure is shown.

In the above configuration, the ball valve 11 normally contacts the valve seat 19 to close the fuel injection hole 3b, but when the electromagnetic coil 5 is energized by a signal from the computer 7, the armature 9 Then, the ball valve 11 moves upward and the upper end 9a of the armature 9 connects to the stator 8.
The valve seat portion 19 comes into contact with the lower end surface 8G of the stopper portion 8b, and the valve seat portion 19 is released, and the fuel in the fuel reservoir 18 is injected from the fuel injection hole 3b. When the signal from the computer 7 is stopped, the armature 9 and the ball valve 11 are moved back down by the elastic force of the return spring 10, and the ball valve 11 comes into contact with the valve seat 19 and closes the fuel injection hole 3b, so that no fuel is supplied. The gushing of is stopped.

In the above operation, the ball valve 11 is in oil-tight contact with the valve seat 19 as shown in FIG. 2(a) when the ball valve is closed.

At this time, the armature 9 is inclined by the clearance between it and the inner peripheral surface 4G of the kite hole 4b of the armature guide 4. When the armature 9 lifts upward and its upper end portion 9a abuts against the lower end surface 8G of the stopper portion 8b of the stator 8, the fuel injection hole 3b is opened as described above. FIG. 2 shows the state of the armature 9 after being lifted.

As mentioned above, the upper end 9a of the armature 9 is formed into a partially spherical shape, so even if the armature 9 remains tilted and collides with the lower end surface 8G of the stopper portion 8b, the collision conditions, such as the collision pressure, are always constant. . Therefore, in this embodiment, in order to precisely guide the movement of the ball valve 11, a highly accurate gap is formed between the armature 9 and the guide hole 4b of the armature guide 4, and the stopper portion 8b of the stator 8 is formed with high accuracy. Even without machining, when the armature 9 collides with the stopper portion 8b, the ball valve 11 hardly bounces back, its operation is stable, and there is no possibility of prying.

In addition, the inner peripheral surface 4c of the guide hole 4b of the armature guide 4 and the upper end 9 of the armature 9 constitute a solid gap.
Since the thickness of the hard chrome plating applied to the outer peripheral surface 9b and the lower end surface 8C of the stopper portion 8b of the stator 8 can be controlled, the attraction force of the electromagnetic coil is stable.

Therefore, the dynamic injection amount of the fuel injection valve 1 can be held within a certain range without adjusting the spring force of the return spring 10.

In the above embodiment, the upper end portion 9a of the armature 9 is partially spherical, and the lower end surface 8 of the stopper portion 8b of the stator 8
Although c is made flat, it may be the other way around. Further, both the upper end 9a of the armature 9 and the lower end surface 8C of the stopper portion 8b may be partially spherical. Further, although the solid gap is made of hard chrome plating, a non-magnetic metal such as 5US304 may be bonded to the stator 8 and armature 9, and the surfaces may be hardened such as nitriding.

FIG. 4 shows a fuel injection valve 21 of a second embodiment.

In this fuel injection valve 21, the valve body 3 is held by bending the end of the extension of the stator 8, and this is held in a case made of an electrically insulating material such as resin, which also serves as an electrical connector. It is attached to main body 2. Other configurations and operations are the same as in the first embodiment. Furthermore, the fifth
The figure is a sectional view of the separate tube station in FIG. 4.

[Effects] Since the present invention has the above configuration, it has the following excellent effects.

(a) Costs are extremely low because expensive precision machining is not required to reduce warping and twisting within the pulp body when the operation of conventional needle valves is restricted.

(b) The ball valve's responsiveness to energization and de-energization of the electromagnetic coil and fuel injection characteristics are excellent.

(c) Maintenance is easy because the conventional complicated adjustment for setting a precise fuel injection amount is not required.

(d) Productivity is extremely high because the structure is simple.

[Brief explanation of drawings]

FIG. 1 shows a longitudinal sectional front view of the first embodiment. Figure 2 (a)
, (b) are both diagrams showing operating state diagrams of the armature. . FIG. 3 shows a longitudinal sectional front view of another part of FIG. 1. FIG. 4 shows a longitudinal sectional front view of the second embodiment. Figure 5 is the 4th
A longitudinal sectional front view of another part of the figure is shown. FIG. 6 shows a longitudinal sectional front view of a conventional fuel injection valve. 1...Fuel injection 2...Case body 3...Valve body 3b...Fuel injection hole 4...
- Armature guide 4b... Guide hole 5... Electromagnetic coil 8... Stator 8b... Stopper part 9...
Armature 9a... Upper end (upstream end) 11...
Ball valve 19...Valve seat portion 21...Fuel injection valve

Claims (1)

[Claims] A stator containing an electromagnetic coil, an armature guide having a guide hole in the center, and a valve body having a fuel injection hole and a conical valve seat communicating with the valve body are housed in a cylindrical case body. They are arranged in the order listed from the upstream side to the downstream side, and a rod-shaped armature is loosely inserted into the guide hole of the armature guide so as to be movable in the axial direction, and the valve body is inserted into the downstream end of the armature by moving the armature in the axial direction. A ball valve that comes into contact with and leaves the valve seat of the stator is attached, and the upstream end of the armature comes into contact with and leaves the end of a stopper provided in the center of the stator as the armature moves in the axial direction, and the shaft of the armature The fuel injection valve moves in the direction by supplying and cutting off current to an electromagnetic coil and the elastic force of an elastic member, and at least one of the upstream end of the armature and the end of the stopper portion of the stator has a partially spherical shape. A fuel injection valve characterized by being formed in.