JPH0225030B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fuel injection valve that is electromagnetically operated to supply fuel to an engine.

In this type of electromagnetic fuel injection valve, the movable iron core is drawn toward the fixed iron core by the attraction force generated by energizing the electromagnetic coil, thereby lifting the valve body integrally connected to the movable iron core. Generally, fuel is injected by opening the fuel passage to the nozzle hole by lifting the fuel. Conventionally, the valve body is configured as a needle valve, and the needle valve is usually inserted into the nozzle body in such a manner that it cannot be tilted.

However, in those using such a needle valve, in order to obtain good movement of the needle valve,
High-precision machining is required for the needle valve and the nozzle body that guides it, and high-precision machining is also required for the valve part of the needle valve and the valve seat that opens and closes it to prevent fuel leakage when the valve is closed. is required, and there are defects that require time and effort to manufacture.

In order to prevent such problems, a valve body has been developed in which the outer circumferential surface of the valve body is spherical and the valve seat is opened and closed using this spherical outer circumferential surface. This product securely seats on the valve seat even if the valve body is tilted, so
Excellent prevention of fuel leakage when the valve is closed.

However, since a valve body with a spherical outer peripheral surface is easily tilted, the valve body and the movable iron core integrally connected to the valve body also tilt, and the attraction force of the electromagnetic coil causes the valve body and the movable core to tilt. When the iron core is lifted, if the movable iron core is tilted, the end corner (shoulder) of the movable iron core will hit the fixed iron core, and this will cause the shoulder to wear out. The shoulder of the movable iron core must be kept sharp due to its magnetic properties. Therefore, wear of the shoulder causes deterioration of the magnetic properties and causes delays and variations in valve opening and valve opening time. This causes fuel injection performance to become unstable.

The present invention has been made based on the above circumstances, and is designed to automatically prevent the valve body and the movable core from tilting even if the valve body and the movable core try to tilt, thereby preventing the shoulder portion of the movable core from coming into contact with the fixed core, and to prevent the shoulder portion of the movable core from coming into contact with the fixed core. The purpose of the present invention is to provide an electromagnetic fuel injection valve that maintains the correct posture and maintains good operation.

In the electromagnetic injection valve of the present invention, the spring contact seat formed on the valve body of the spring that presses and biases the valve body in the valve closing direction is positioned in the spring pressing direction with respect to the center of gravity of the combined body of the valve body and the movable iron core. By forming it on the forward side of the valve body and on the forward side in the spring pressing direction from the center of curvature of the spherical surface formed on the outer peripheral surface of the valve body, the inclination of the valve body and the movable iron core can be automatically corrected. This is what I did.

An embodiment of the present invention will be described below based on FIG. 1 and FIGS. 2a and 2b.

FIG. 1 shows a fuel injection valve 1 improved for low-pressure injection, and 3 generally shows a delivery pipe connected to this fuel injection valve 1.

The fuel injection valve 1 has a housing 10 and a body 11 coupled to the tip of the housing 10, both of which constitute an injection valve main body.

A coil assembly consisting of an electromagnetic coil 12 and fixed iron cores 13 and 14 is fixed inside the injection valve bodies 10 and 11. The coil assembly is formed into a cylindrical shape as a whole by arranging the electromagnetic coil 12 between a cylindrical inner fixed core 13 and an outer fixed core 14, and the inner fixed core 13 is caulked or crimped with the outer fixed core 14. The housing 10 and the spacer 1 are integrally assembled by welding or the like, and the plurality of radial projections 14a of the outer fixed core 14 are assembled together by welding or the like.
8, the injection valve body 1
It is fixed inside 0,11. Furthermore, electromagnetic coil 1
2 is operated by receiving a pulse voltage supplied from a control circuit (not shown) via a connector 12a.

By fixing the coil assembly, the main body 10,1
1 includes the coil assemblies 12, 13, 1
A chamber 19 is formed on one end surface side of 4. This room 19
Fuel from an inlet passage 20 provided in the housing 10 enters through the inside of the pipe 17 and the inside of the coil assembly. The fuel in this chamber 19 is adapted to flow through the gap 14b between the protrusions 14a and out of the outer periphery 19a of the coil assembly and an outlet passage 21 provided in the housing 10. The inlet passage 20 and the outlet passage 21 are the supply passage 30 and the discharge passage 31 of the delivery pipe 3, respectively.
It is familiar to Note that 22 indicates a filter.

A valve seat 23 is installed in the body 11. This valve seat 23 communicates with an injection hole 25 through an injection passage 24 .

The chamber 19 accommodates a valve assembly consisting of a movable core 15 and a valve body 16 integrally coupled to the movable core 15 by welding or the like. The movable core 15 is disk-shaped, and faces the entire surface of one end surface of both the inner and outer fixed cores 13 and 14, so that the movable core 15 is connected to the fixed core 13 when the electromagnetic coil 12 is energized. , 14 form a nearly complete magnetic circuit, and are attracted to the fixed cores 13, 14.

The valve body 16 is formed into a substantially hemispherical shape with a spherical outer peripheral surface 16a, and is connected to the center of the movable iron core 15. The spherical outer peripheral surface 16a is the valve seat 23
The opening of this valve seat 23 is opened and closed by approaching and separating it. Such valve combinations 15 and 16 are biased by a spring 26. One end of the spring 26 is in contact with the valve coupling bodies 15 and 16, and the other end is inserted into the inside of the inner fixed core 13 and is connected to the pipe 17.
is in contact with the end face of the

Thus, an abutment seat 16b for supporting one end of the spring 26 is formed in the valve combination bodies 15 and 16. This abutment seat 16b has an insertion hole 16c formed in the center of the valve body 16 from the movable iron core 15 side, and is formed on the abutment surface of this insertion hole 16c. and the center of gravity G of the combined body of the movable iron core 15, the spring 2
6 in the pressing direction, that is, the center of gravity G in the figure.
The spring 26 is located further downward than the center of curvature C of the spherical outer circumferential surface 16a of the valve body 16 in the pressing direction of the spring 26, that is, it is located below C.

Note that the valve body 16 has the insertion hole 16c and the chamber 1.
A hole 27 is formed to communicate with the chamber 19, and fuel sent from the inlet passage 20 is supplied to the chamber 19 through the insertion hole 16c and the hole 27. The movable core 15 also has a chamber 19 and an annular groove 19 formed on the end face of the coil assembly facing the valve body.
A hole 15a is formed to communicate with the hole 15a.

Furthermore, as can be seen from FIG. 1, the fuel injection valve 1 is attached to the engine I;
is installed so that its axis is inclined with respect to both the vertical and horizontal directions, and the inlet passage 20 is positioned lower than the outlet passage 21 in the vertical direction.

The operation of the embodiment having such a configuration will be explained with reference to FIGS. 2a and 2b.

When the electromagnetic coil 12 is de-energized, the spring 26 presses the valve combination bodies 15 and 16, so the spherical outer peripheral surface 16a of the valve body 16 seats on the valve seat 23 and closes the opening of the valve seat 23. . In this case, since the outer circumferential surface 16a of the valve body 16 is formed in a spherical shape, the outer circumferential surface 16a is stably seated on the valve seat 23 and performs a good valve closing action. Furthermore, even if the valve body 16 is seated with a slight inclination, the outer circumferential surface 16a
Since it is a spherical surface, the valve can be reliably closed. However, if the valve body 16 is to be seated at an angle, the abutting seat 16b of the spring 26 will be positioned below the center of curvature C of the spherical outer circumferential surface 16a, as shown in FIG. 2a. Therefore, the center point A of the pressing action of the spring 26 is located at the center of curvature C.
The spring pressing force F _s applied to this point of action A, which is located further down, generates a moment around the center of curvature C, causing the valve body 16 to rotate in the direction of the arrow in FIG. 2a. Therefore, the inclination of the valve body 16 is corrected, and the valve is closed more reliably.

When the valve is closed, fuel flows from the supply passage 30 of the delivery pipe 3 through the inlet passage 20 to the chamber 1.
9 and the fuel in this chamber 19 is supplied to the outer peripheral part 19.
a is returned to the discharge passage 31 of the delivery pipe 3 via the outlet passage 21. That is, since the fuel is circulated within the fuel injection valve 1, the fuel injection valve 1, which is susceptible to heat from the engine I, is cooled. Furthermore, even if vapor is generated within the valve 1, this vapor is carried away by the circulation flow of the fuel and is removed to the delivery pipe 3 side.
In particular, by providing the outlet passage 21 above the inlet passage 20, vapor can be quickly removed based on the weight ratio of vapor and fuel.

When the electromagnetic coil 12 is energized from an electronic control device (not shown), the movable core 15 and the valve body 16 are attracted to the fixed cores 13 and 14, and are lifted against the spring 26. Therefore, the spherical outer circumferential surface 16a of the valve body 16 separates from the valve seat 23, so that the fuel in the chamber 19 is branched to the injection passage 24 and the nozzle hole 25.
It is squirted into the engine.

The movable core 15 is attracted to the fixed cores 13 and 14, but the movable core 15 tilts and the fixed cores 13 and 14
2b, the abutting seat 16b of the spring 26 will move forward of the center of gravity G of the combination of the valve body 16 and the movable iron core 15, that is, as shown in FIG. 2b. Since it is formed downward, the spring 2 applied to the point of action A of the spring 26
Due to the pressing force F _s of 6, a moment acts on the valve combinations 15, 16 around the center of gravity G, and the valve combinations 15, 1
6 is rotated in the direction of the arrow in FIG. 2b. Therefore, the movable core 15 is prevented from tilting and hitting the fixed cores 13 and 14, and the end corners of the movable core 15,
In other words, the shoulder portion 15b is locally fixed to the fixed cores 13, 14.
There will be no more collisions. Therefore, movable iron core 1
Wear of the shoulder portion 15b of No. 5 is prevented, and deterioration of magnetic properties is eliminated. Therefore, changes over time in delays in opening/closing and valve closing times due to deterioration of magnetic characteristics are prevented, and variations are also prevented, resulting in stable injection characteristics.

In particular, when the fuel injection valve 1 is installed inclined both vertically and horizontally as shown in FIG. 1, the valve combinations 15 and 16 tend to tilt. This is effective because it prevents the slope from tilting.

As detailed above, according to the present invention, the abutting seat of the spring that biases the valve body in the valve closing direction is formed on the forward side in the pressing direction of the spring with respect to the center of gravity of the combined body of the valve body and the movable iron core. By locating the valve element on the forward side in the spring's pressing direction than the center of curvature of the spherical outer circumferential surface of the valve body, the valve coupling body is prevented from tilting during valve closing and lifting, thereby ensuring reliable valve closing and preventing the movement of the movable iron core. Shoulder contact is also prevented, deterioration of magnetic properties is prevented, time delays and variations in valve opening and closing are eliminated, and the injection amount is stabilized, resulting in good injection performance.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention, and FIG. 1 is a sectional view of a fuel injection valve, and FIGS. 2a and 2b are explanatory diagrams of main parts for explaining the operation when the valve is closed and when the valve is opened, respectively. be. 1... Fuel injection valve, 10, 11... Injection valve body, 12... Electromagnetic coil, 13, 14... Fixed iron core, 19... Chamber, 20... Inflow passage, 21... Outflow passage, 23... Valve seat, 15...Movable iron core, 16
... Valve body, 16a ... Spherical outer peripheral surface, 16b ...
Spring contact seat, 26...spring.

Claims (1)

[Scope of Claims] 1. A coil assembly including an electromagnetic coil and a fixed iron core is provided inside the injection valve body, and a coil assembly is located inside the injection valve body on one end surface side of the coil assembly to supply fuel from an inlet passage. A chamber into which is introduced is formed, an injection passage leading to the nozzle hole is opened in this chamber, a valve seat is formed in this opening, and this chamber has a spherical outer circumferential surface that approaches and separates from the valve seat. A combined body combining a valve body and a disk-shaped movable core is housed so that the movable core faces one end surface of the coil assembly and can freely float, and is installed at an angle to an internal combustion engine. In the electromagnetic fuel injection valve, an insertion hole having an abutment seat at the inner end is formed in the combined body of the valve body and the movable iron core, and one end of a spring that biases the valve body in the valve closing direction is provided. The spring is brought into contact with one end surface of the coil assembly, and the other end is brought into contact with the abutment seat of the insertion hole, and the spring abutment seat is positioned so that the spring is lower than the center of gravity of the combined body of the valve body and the movable iron core. An electromagnetic fuel injection valve characterized in that it is located on the tip side in the pressing direction and further on the tip side in the spring pressing direction with respect to the center of curvature of the spherical outer circumferential surface.