JPS60192874A - Solenoid type fuel injection valve - Google Patents

Abstract

PURPOSE:To preent the magnetic characteristics from deteriorating, secure a large magnetic path, and allow a smooth needle valve action by using the specific coupling between a needle valve having lugs and hook sections and a movable core. CONSTITUTION:A needle valve 3 is inserted by pressure into a movable core 20 for coupling until the lugs 22 of the needle valve 3 reach a coupling hole 23 and the hook sections at the tips of the lugs 22 reach a bag hole 24. When the hook sections 27 reach the bag hole 24, the hook sections 27 are engaged with a step section 24a. Concurrently with this engagement, a gap portion 37 is formed on the needle valve 3 side on the coupling end surface among the tapered inner peripheral surface 23a of the coupling hole 23, the outer side surfaces 22a of the lugs 22, the movable core 20, and the needle valve 3. Accordingly, the needle valve 3 and the movable core 20 are coupled and moved in the axial direction in one body.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electromagnetic fuel injection valve used particularly as a fuel supply device for an internal combustion engine.

[Prior art]

In conventional electromagnetic fuel injection valves, the structure of the connecting part between the needle valve and the movable core of the injector is such that the needle valve is screwed into the movable core and fixed with adhesive. This has the disadvantage that, as it spreads, it reaches the needle valve guide and obstructs the movement of the needle valve.

In addition, in order to eliminate this drawback,
As seen in Publication No. 1, there is a method in which a concavo-convex portion consisting of an annular groove and a raised portion is provided on the needle valve, and the core hole of the movable core and the concave-convex portion are pressed together. When the hole is crimped, the magnetic properties of the core member deteriorate due to plastic deformation of the core member of the movable core, and the uneven portion of the needle valve occupies a large proportion of the cross-sectional area inside the movable core, so the magnetic path is It has drawbacks such as being narrow.

[Purpose of the invention]

An object of the present invention is to provide an electromagnetic fuel injection valve that eliminates the deterioration of the magnetic properties and secures a large magnetic path to enable smooth needle valve operation.

In order to achieve the above object, the present invention provides an electromagnetic fuel injection valve including a needle valve and a movable core, including a plurality of protrusions at one end of the needle valve, and a locking member provided at the tip of the protrusion. A needle valve having a stop part is connected to a fitting hole provided from the end surface of the movable core, a blind hole forming a stepped part that engages with the locking part, and a communicating hole leading from the other end of the movable core to the blind hole. The protrusion is press-fitted into a fitting hole of a movable core having a core hole, the locking part and the stepped part are engaged, and the outer side surface of the protrusion is press-fitted to the inner circumferential surface of the fitting hole.

〔Example〕

FIG. 1 and FIG. 2 regarding the first embodiment of the present invention
, (b).

In FIG. 1, reference numeral 1 denotes a housing, and a nozzle body 2 is held at the lower end by a shark holder 1a.

A needle valve 3 is housed in the nozzle body 2 so as to be movable in the axial direction. When the needle valve 3 is seated on the valve seat 4 of the nozzle body 2, the fuel injection hole 5 is closed. When it leaves the seat 4, the fuel injection hole 5 opens.

A tubular fixed core 6 is provided in the center of the housing 1, and the fixed core 6 is fixed to the housing 1 by squeezing the upper end 1b of the housing 1.

An electromagnetic coil 8 wound around a spool 7 is housed in an annular space formed between the housing l and the fixed iron core 6. The spool 7 is fitted into the housing 1 and the fixed core 6 via O-rings 9 and 10 in a fluid-tight manner. The electromagnetic coil 8 is connected to a terminal 12 mounted inside a synthetic resin connector 11 integrated with the housing 1. This terminal 12 is connected to an electronic control unit (CPU) 13 such as a computer, receives current pulses from the electronic control unit 13, and transmits the current pulses to the electromagnetic coil 8.

The upper end of the fixed iron core 6 is a connector pipe 14 that is connected to a fuel supply pipe (not shown).
is supplied with fuel adjusted to a predetermined pressure. The fuel passes through a filter 15 and flows through a fuel passage 17 provided in the center of the fixed iron core 6. An adjustment pipe 18 is accommodated in the central space of the fixed iron core 6.
The fuel passage 17 is substantially connected to this adjustment pipe 18.
It is the internal space of

The adjustment pipe 18 is fixed to the fixed iron core 6 by tightening the upper part 6a of the fixed iron core 6.

The upper end of a spring 19 is in contact with the lower end of this adjustment pipe 18. The lower end of the spring 19 is in contact with the upper end of the movable core 20. The set load of the spring 19 is set by adjusting the position at which the adjust pipe 18 is fixed to the fixed iron core 6.

The movable core 20 is housed so as to be movable in the axial direction within the housing 1, and a core hole 21 is formed in the movable core 20.

Regarding the connection between the needle valve 3 and the movable core 20, see FIG.
This will be explained in al and fbl.

Four plate-shaped protrusions 22 are formed on the shaft portion 3a of the needle valve 3 at predetermined intervals along the outer circumferential axis direction of the shaft portion 3a. This protrusion 22 has a leaf spring action, and this protrusion 22
The plate thickness of the protrusion 22 gradually becomes thinner from the middle of the protrusion 2, and the outer side surface 22a has an inclination in the direction in which the protrusion 22 is formed. Furthermore, a claw-like locking portion 27 is provided at the tip of the protrusion 22 in the outer circumferential direction. Furthermore, the shaft portion 3a
A recess 3b is provided on the protruding end surface of the protrusion 22.

A core hole 21 consisting of a fitting hole 23, a blind hole 24, and a communication hole 29 is formed coaxially in the movable core 20 in the axial direction.

The fitting hole 23 is formed from the end surface of the movable core 20 on the side connected to the needle valve 3, and the inner diameter of the fitting hole 23 on the end surface is equal to or slightly smaller than the outer diameter of the shaft portion 3a of the needle valve 3. It's a big one.

Further, the fitting hole 23 has a tapered inner circumferential surface 23a that gradually narrows toward the inside of the core hole 21 in the axial direction. Note that the fitting hole 23 extends to about 1/2 of the core hole 21.

The blind hole 24 is provided from the narrow mouth 23b of the fitting hole 23, and the diameter of the blind hole 24 is a cylindrical hole that is equal to or slightly larger than the shaft portion 3a of the needle valve 3. 23 and the blind hole 24 form a stepped portion 24a.

The communication hole 29 is a cylindrical hole that communicates with the blind hole 24 from the end surface of the movable core 20 facing the fixed iron core 6 through a gap, and the inner diameter of the communication hole 29 is smaller than the inner diameter of the blind hole 24. There is.

Needle valve 3 and movable core 20 having the above-described configuration
The protrusion 22 of the needle valve 3 is press-fitted into the fitting hole 23 until the locking part 27 at the tip of the protrusion 22 reaches the blind hole 24. When the locking part 27 reaches the blind hole 24, the locking part 2
7 and the stepped portion 24a engage with each other. At the same time as this engagement, the tapered inner circumferential surface 23a of the fitting hole 23 and the outer side surface 2 of the protrusion 22
2a, a gap portion 37 is formed on the needle valve 3 side of the joint end surface between the movable core 20 and the needle valve 3.

As a result, the needle valve 3 and the movable core 20 are integrally coupled and move together in the axial direction.

Referring again to FIG. 1, the needle valve 3 is provided with a flange 31 serving as a stopper, and guide portions 32 and 33 are formed below this flange 31. These guide parts 32 and 33 slide with respect to the sliding hole 40 of the nozzle body 2 via a gap. Moreover, these guide portions 32.
33, a fuel passage 34 is secured between them. The needle valve 3 is electrically connected through the through hole 36 of the spacer 35 via a gap. Further, when the needle valve 3 is moved (lifted) upward, the flange 31 hits the spacer 35, and the amount of lift is regulated.

Note that 41 is an O ring provided between the nozzle body 2 and the housing 1.

In the electromagnetic fuel injection valve configured as described above, fuel pressurized to a constant pressure is supplied through the connector pipe 14. This fuel passes through the filter 15 to the adjustment pipe 1
It passes through the fuel passage 17 in the movable core 20, reaches around the spring 19, passes through the core hole 21 of the movable core 20, the gap 37 provided in the shaft portion 3a on the downstream side of the movable core 20, and the through hole 36, and further passes through the guide. The valve seat 4 is reached through a fuel passage 34 which is a gap between the part 3.2.33 and the sliding hole 40.

Then, a current pulse is transmitted from the electronic control device 13 to the electromagnetic coil 8.
If the fixed core 6 is not magnetized, the movable core 20 is pushed down by the pressing force of the spring 19, and the needle valve 3 is in close contact with the valve seat 4, closing the fuel injection valve 5. . Therefore, no fuel is injected.

When a current pulse is applied from the electronic control device 13 to the electromagnetic coil 8, the fixed core 6 is magnetized, and the movable core 20
is attracted to the fixed iron core 6 against the force of the spring 19. For this reason, the needle valve 3 connected to the movable core 20 is lifted and is therefore separated from the valve seat 4, so that the fuel injection hole 5 is opened and the fuel that has reached just before the fuel injection hole 5 is injected.

When the application of the current pulse to the electromagnetic coil 8 ends,
Since the magnetization of the fixed iron core 6 disappears, the attractive force of the fixed iron core 6 to the movable core 20 disappears, and the movable core 20 is moved downward under the pressing force of the spring 19, so that the needle valve 3 is moved downward from the valve seat 4. Since it is seated in the fuel injection hole 5
Close the valve to finish fuel injection.

Next, FIG. 3(a) shows a second embodiment of the present invention.

tb).

In this embodiment, the length of the protrusion 22 provided on the shaft portion 3a of the needle valve 3 is set to a length that fits into the fitting hole 23 of the movable core 20, and the needle is inserted into the shaft portion 3a along the axial direction. A fuel conduction hole 39 that reaches the position of the gap portion 37 in the first embodiment when the valve 3 and the movable core 20 are connected.
A bypass hole 38 is provided to allow the fuel introduced into the fuel conduction hole 39 in the radial direction of the shaft portion 3a to reach the periphery of the shaft portion 3a.
is the shaft portion 3a when the needle valve 3 and the movable core 20 are connected.
installed on the exposed part of the In addition, needle valve 3
The connection between the movable core 20, the shapes of other members, and the operation are the same as in the first embodiment described above.

Note that the fuel passage hole 39 is connected to the guide portion 32 of the needle valve 3.
．． 33, and a bypass hole 38 may be provided between the guide portions 32 and 33.

And the first one mentioned above. In the second embodiment, the number of protrusions 22 is four, but the number of protrusions 22 is not limited to this and may be any number as long as it is plural.

〔Effect of the invention〕

As described above, in the present invention, in an electromagnetic fuel injection valve including a needle valve and a movable core, a plurality of protrusions are provided at one end of the needle valve, and a locking portion provided at the tip of the protrusion. A core comprising a fitting hole provided from the end surface of the movable core, a blind hole forming a step that engages with the locking part, and a communicating hole communicating from the other end of the movable core to the blind hole. The protrusion is press-fitted into the fitting hole of the movable core having a hole, the locking part and the stepped part are engaged, and the outer side surface of the protrusion is crimped to the inner peripheral surface of the fitting hole, so it can be used as a needle valve. When connected to the movable core, the conventional process of plastic deformation of the core member is eliminated, eliminating deterioration of the magnetic properties of the core member due to plastic deformation, and the cross-sectional area occupied inside the movable core of the joint part of the needle valve with the movable core. The ratio is about the same as that of the shaft of the needle valve, and a larger magnetic path can be secured compared to conventional ones. Therefore, smooth operation of the needle valve is possible, and in the above connection, the connection between the needle valve and the movable core is This has the excellent effect of simplifying the post-coupling process.

[Brief explanation of drawings]

FIG. 1 is a sectional view of an electromagnetic fuel injection valve having the configuration of the first embodiment of the present invention, and FIG. Figure - (bl is the second
3 (a) is a main part front view showing the structure of the needle valve side coupling part of the second embodiment of the present invention, and FIG. It is a sectional view showing the composition of the movable core side connection part of the 2nd example. 1... Housing, 3... Needle valve, 20...
Movable core, 21... Core hole, 22... Protrusion, 22a
... External side surface, 23 ... Fitting hole, 23a ... Inner peripheral surface, 24 ... Blind hole, 24a ... Step part, 27 ... Locking part, 29 ... Communication hole .

Claims (1)

[Claims] In an electromagnetic fuel injection valve in which a needle valve and a movable core are fixed and are movable in an axial direction inside a housing, a plurality of protrusions having a handling spring action are provided at one end of the needle valve; The needle valve has a claw-like locking part provided at the tip of the protrusion and formed in the outer circumferential direction of the needle valve, and the needle valve has a tapered inner peripheral surface that is provided from an end surface of the movable core and gradually narrows from the end surface. The fitting hole of the movable core has a core hole including a fitting hole having a fitting hole, a blind hole forming a stepped portion that engages with the locking portion, and a communicating hole extending from the other end surface of the movable core to the blind hole. The electromagnetic type is press-fitted into the fitting hole, the locking part and the stepped part of the blind hole are engaged, and the outer side surface of the protrusion is pressed against the inner circumferential surface of the fitting hole. fuel injection valve.