JPS6151145B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electromagnetic fuel injection valve used for fuel injection in an engine, and more particularly to a fuel injection valve of a type in which a movable core is moved to intermittent fuel injection.

Conventionally, in an electromagnetic fuel injection valve such as that shown in Japanese Utility Model Application Publication No. 51-4806, the fuel is cut off by pressing a rubber flat plate valve body using the spring force of a compression coil spring disposed in a recessed part of a movable core. The fuel is injected by pressing the convex valve seat of the resin body through the movable core, and the fuel is injected by energizing the electromagnetic coil to move the movable core against the compression coil spring. This is done by opening. The amount of displacement of the movable core when the valve is opened is regulated by the movable core coming into contact with metal fixed cores that are provided facing each other at a predetermined interval.

However, the conventional fuel injection valve as described above has a drawback in that sufficient durability is not achieved as described below. In other words, the displacement of the movable core is regulated by bringing the movable core into contact with the fixed core, and since both are made of metal, the impact force of the contact is large, which increases the number of times the fuel injection valve operates. As a result, the amount of wear increases, resulting in changes in the characteristics of the fuel injection amount, and in this respect, sufficient durability has not been achieved. In addition, since the compression coil spring is installed in the recess of the movable core, repeated movement of the movable core causes the compression coil spring to come into contact with the surface of the recess of the movable core, which gradually increases the amount of wear and tends to lead to breakage. In this respect as well, sufficient durability was not achieved.

The present invention has been made in view of the above points, and
It is an object of the present invention to provide an electromagnetic fuel injection valve that has sufficient durability even if it is operated many times. In particular, the present invention provides a shock absorber made of a rubber material on one of the movable core and the fixed core, and coats the surface that contacts the other shock absorber with a non-adhesive synthetic resin material such as tetrafluoroethylene resin, Furthermore, the movable core is characterized by a configuration in which a cylinder made of a non-adhesive synthetic resin material is provided in the recessed portion of the movable core, and this configuration solves the above-mentioned problems.

The present invention will be explained below with reference to embodiments shown in the drawings.
In the figure, a main body 1 of an electromagnetic fuel injection valve is made of synthetic resin, and an electrical connector 2 for wiring.
are integrated. A wiring terminal 3 is coated with an epoxy adhesive and embedded in the electrical connector 2.

The injection valve body 1 is integrally formed with a fuel inlet 4 through which fuel such as LPG is introduced, fuel passages 5 and 6, a planar valve seat 7, and a bobbin 8 consisting of a collar-shaped portion. An electromagnetic coil 9 connected to the terminal 3 is wound around the bobbin 8.

The movable core 10 is made of a magnetic material such as iron, and is movably installed within the fuel passage 6. In addition, a rubber valve body 11 is baked and fixed on the left end surface of the movable core 10 in the figure to abut against the planar valve seat 7 and close the fuel passage 5, and on the other hand, a ring-shaped valve body 11 is fixed on the right end surface in the figure. A shock absorber 12 made of fluorocarbon rubber, silicone rubber, etc. is fixed by baking.

Furthermore, the movable core 10 has a cylindrical recess 13 formed therein, and a cylindrical body 14 made of non-adhesive synthetic resin such as tetrafluoroethylene resin or polypropylene resin is inserted and fixed into the inner peripheral part of this recess 13. There is. A compression coil spring 15 is disposed inside this cylindrical body 14, and the movable core 10 is pressed by this spring 15 in a direction to close the fuel passage 5.

A metal housing 20 is coupled to the main body 1, and a fuel injection pipe 21 is fixed to the housing 20. A fuel passage 22 is formed inside the fuel injection pipe 21, and a nozzle 23 for measuring injected fuel is provided at the tip thereof. Also,
A fixed core 24 for regulating the amount of movement of the movable core 10 is press-fitted and fixed to the left end of the fuel injection pipe 21 in the figure so as to face the movable core 10 . The surface 27 of the fixed core 24 that comes into contact with the shock absorber 12 is coated with a non-adhesive synthetic resin material such as tetrafluoroethylene resin or polypropylene resin.

An O-ring 2 is installed between the fuel injection pipe 21 and the main body 1.
5 is installed, and an O-ring 26 is installed between the housing 20 and the thick part of the main body 1. Among these, the O-ring 26 allows fuel to flow out from the gap between the housing 20 and the main body 1 even if a particularly thin part of the resin main body 1, such as the coil-wound part, breaks due to careless external force. I try not to.

The operation of the electromagnetic fuel injection valve according to the present invention in the above configuration will be explained. An electrical control circuit (not shown) controls the supply of electricity to the fuel injection valve to inject and cut off fuel. Among these, fuel injection is performed by energizing the electromagnetic coil 9.
When energized, the movable core 10 moves to the right from the illustrated position (valve closed position) against the spring force of the spring 15, opens the fuel passage 5, and guides fuel to the nozzle 23. The fuel is then injected from the nozzle 23 into an intake pipe of an engine (not shown).

Here, the amount of movement of the movable core 10 is regulated by the impact absorber 12 coming into contact with the end surface 27 of the fixed core 24, but the impact force at the time of this contact is sufficiently absorbed by the absorber 12. As a result, wear of the movable core 10 and the fixed core 24 is prevented, and the impact noise generated at this time is also reduced. In addition, the absorber 12
Since the end surface 27 of the fixed core 24 that comes into contact with is coated with a non-adhesive synthetic resin material, deterioration such as abrasion and adhesion of the absorbent body 12 is prevented.

The fuel is cut off by stopping the power supply to the electromagnetic coil 9. When the power supply to the electromagnetic coil 9 is stopped, the movable core 10 is moved against the planar valve seat of the main body 1 by the spring force of the spring 15. When the valve element 11 of the movable core 10 is pressed against the valve seat 7, the fuel passage 5 is closed and fuel injection is interrupted.
Here, it is preferable to make the valve seat 7 flat, so that no concentrated local force is applied to the valve body 11, so that cracks etc. do not occur on the valve body 11, and the fuel It is effective in preventing problems such as cutting and cutting defects.

By the way, as the movable core 10 moves as described above, the coil spring 15 repeatedly expands and contracts, but since the coil spring 15 contacts the inner surface of the cylindrical body 14 made of a non-adhesive synthetic resin material and smoothly expands and contracts,
Abrasion, breakage, etc. of the coil spring 15 that would occur when the coil spring 15 expands and contracts by directly contacting the inner surface of the movable core 10 can be effectively prevented. Therefore, the electromagnetic fuel injection valve according to the present invention has significantly improved durability compared to conventional ones.

In addition, in the above embodiment, the absorber 12 is connected to the movable core 1.
0 and the end surface of the fixed core 24 is coated with a resin, but the absorber 12 may be fixed to the fixed core 24 and the end surface of the movable core 10 may be coated with a resin.

As described above, according to the present invention, the wear of the movable core and the fixed core can be prevented, and the wear of the spring for actuating the movable core can also be prevented, and the durability of the fuel injection valve can be significantly improved. play.

[Brief explanation of the drawing]

The figure is a longitudinal sectional view showing an embodiment of the present invention. DESCRIPTION OF SYMBOLS 1...Injection valve body, 5...Fuel passage, 9...Electromagnetic coil, 10...Movable core, 12...Shock absorber, 13...Recess, 14...Cylinder body, 15...Spring, 24... …Fixed core.

Claims (1)

[Claims] 1. An electromagnetic coil installed in the injection valve body, a movable core that moves to open a fuel passage when the electromagnetic coil is energized, and a movable core provided opposite to the movable core,
In the electromagnetic fuel injection valve, the electromagnetic fuel injection valve includes a fixed core that regulates the amount of movement of the movable core, and a spring that is disposed in a recess of the movable core and presses the movable core in a direction to close the fuel passage. , a shock absorber made of a rubber material is provided on one side of the fixed core, a non-adhesive synthetic resin material is coated on the other surfaces of the movable core and the fixed core that come into contact with the shock absorber, and a recessed portion of the movable core. An electromagnetic fuel injection valve characterized by having a cylindrical body made of a non-adhesive synthetic resin material.