JPH0583360U - Electromagnetic fuel injection valve - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide an electromagnetic fuel injection valve that improves the responsiveness by reducing the influence of the magnetic flux due to the eddy current generated when the current flowing through the solenoid coil that drives the needle valve is turned off. To do. [Structure] FIG. 1 is a sectional view of an electromagnetic fuel injection valve.
Is a casing, 2a is an inner magnetic core, 2b is an outer magnetic core, and 4 is a solenoid coil that winds the inner magnetic core 2a around a bobbin 3. Further, 6 is a fuel passage. In the present invention, the inner magnetic core 2a of the sleeve 2 is
The outer magnetic core 2b is divided into slits 12 in the direction of the central axis thereof. As a result, when the current flowing through the solenoid coil 4 is turned off, the inner and outer magnetic cores 2
The eddy current generated in a and 2b can be reduced.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an electromagnetic fuel injection valve, and in particular, by reducing the eddy current generated in the magnetic core when the current flowing through the solenoid coil is turned off, the magnetic flux generated due to the eddy current is reduced. -It relates to an electromagnetic fuel injection valve with improved responsiveness of the dollar valve.

[0002]

[Prior Art]

 FIG. 4 is a vertical cross-sectional view showing an example of a conventional electromagnetic fuel injection valve, and fuel flows into the electromagnetic fuel injection valve in the direction of arrow Z parallel to the central axis. In the figure, a strainer 31 for removing foreign matter having a filter net is inserted into the fuel inlet.

Inside the casing 23 formed of a magnetic material in a cylindrical shape, a hollow pipe (hereinafter, simply referred to as a pipe) 23c for fuel guide, which is also formed of a magnetic material, and a fixing united with the hollow pipe 23c. The iron core 23b is inserted. In the space formed by the casing 23 and the fixed iron core 23b, a solenoid coil (hereinafter, simply referred to as coil) 22 wound around the bobbin 21 is housed so as to surround the fixed iron core 23b. ..

A coil spring 26 and a pipe-shaped spring stopper 27 are inserted in the fixed iron core 23b and the pipe 23c, and the spring stopper 27 presses the movable iron core 24 with appropriate force. It is fixed to the casing 23 at such a position.

A valve seat 28, in which a needle valve (hereinafter, simply referred to as “valve”) 25 is inserted, is arranged at the center of the front end of the casing 23, and the casing 23 is caulked at the open end thereof. Has been.

A fuel passage is provided between the valve 25 and the valve seat 28, and the valve 25 is defined by the valve stopper 27 so as to make a constant reciprocating motion corresponding to the valve opening degree.

In the electromagnetic fuel injection valve having the above structure, the fuel filtered by the strainer 31 passes through the center of the spring stopper 27 and is supplied into the valve seat 28. At this time, when current is supplied to the coil 22 and is energized, the movable iron core 24 is attracted to the lower end of the fixed iron core 23b against the repulsive force of the spring 26, so that the valve 25 separates from the valve seat 28. The fuel supplied into the valve seat 28 is injected from the injection port 30. Note that FIG. 4 shows a state in which the coil 22 is not energized.

[0008]

[Problems to be solved by the device]

 Since the electromagnetic fuel injection valve having the above-mentioned structure supplies the current to the coil 22, an eddy current is generated in the plane perpendicular to the magnetic flux in the magnetic circuit when the current is off.

For example, as shown in FIG. 5, eddy currents 32 and 33 are generated on the outer peripheral surface of the fixed magnetic core 23b and the outer magnetic core 23a that also serves as the casing. Note that FIG. 5 is a sectional view taken along the line CC of FIG.

A magnetic flux is generated by the eddy currents 32 and 33, and the attraction force acts on the movable iron core 24 connected to the needle valve 25 even after the current is turned off. In particular, in an electromagnetic fuel injection valve that requires a high output, the higher the hold current, the stronger the above effect.

Conventionally, the casing 23 is made of a magnetic material having a high electric resistivity as a countermeasure, but it is not possible to sufficiently reduce the eddy current, and the operation response of the movable iron core 24 is poor. was there.

The object of the present invention is to solve the above-mentioned problems, to sufficiently reduce the eddy current generated in the fixed iron core or the outer magnetic core constituting the casing, and to wind the coil wound around the fixed iron core. The purpose of the present invention is to provide an electromagnetic fuel injection valve that improves the responsiveness of the needle valve when the current flowing in the valve is turned off.

[0013]

[Means for Solving the Problems]

 In order to achieve the above-mentioned object, the present invention is characterized in that a magnetic core around which a solenoid coil is wound is divided into slits in the direction of its central axis.

[0014]

[Action]

 According to the above configuration, since the slit is provided in the magnetic core, the magnetic circuit parallel to the magnetic flux is divided, and the path through which the eddy current flows becomes long. As a result, the electrical resistance increased and it became difficult for eddy currents to flow.

As a result, it is possible to reduce the eddy current generated when the current is off, accelerate the decrease of the magnetic flux when the current is off, and improve the response of the electromagnetic fuel injection valve.

[0016]

【Example】

 Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 1 is a longitudinal sectional view of a main part of an electromagnetic fuel injection valve according to an embodiment of the present invention, FIG. 2 is a sectional view taken along the line AA of FIG. 1, and FIG. 3 is a part of FIG. It is a block diagram of.

In FIG. 1, 1 is a casing, 2 is a sleeve, and 2 a and 2 b are an inner magnetic core and an outer magnetic core which are a part of the sleeve 2. Further, 3 is a bobbin, 4 is a solenoid coil, 5 is a foreign matter removing strainer, 6 is a fuel passage, 7 is a spring coil, and 8 is a movable iron core. Further, 10 is a needle valve and 11 is a valve sheet, which is detachably configured by a cap nut 15. Further, 12 in FIG. 2 is a plurality of slits formed in the magnetic cores 2a and 2b.

Note that the reference numerals in FIGS. 2 and 3 indicate the same or equivalent parts to those in FIG.

In this embodiment, eight slits 12 having a depth B are formed in the inner and outer magnetic cores 2a and 2b of the sleeve 2 at equal intervals. These slits 12 have a width of 0..0 so as to be parallel to the magnetic flux in the magnetic circuit after the sleeve 2 is magnetically annealed. It can be created by wire cutting to 2 mm.

When electric current is supplied to the coil 4 of FIG. 1, the valve 10 is lifted and fuel is injected, and then the electric current is turned off, the inside of the inner and outer magnetic cores 2a and 2b are Eddy current is generated in the.

At this time, in this embodiment, since eight slits 12 are formed in the inner and outer magnetic cores 2a and 2b and are divided from each other, the eddy current is generated in the conventional device described in FIG. As described above, it does not occur on the peripheral surface of the entire magnetic core, but occurs on the peripheral surface of each dividing portion as shown in FIG.

By the way, comparing the perimeter of a magnetic core having a circular cross section which is not divided as in the conventional case, and the total perimeter of the magnetic core divided into eight as in the present embodiment, the latter is 2 More than double the length.

For example, when the diameter of the magnetic core is 10, the circumference of the domain wall is 31.4, but when it is divided into eight, it is about 71.4. That is, when the magnetic circuit is divided, the path of the eddy current becomes twice as long or longer.

As described above, when the circumference of the magnetic core becomes long, the electrical resistance of the eddy current increases, and when the current supplied to the coil 4 is turned off, the inner and outer magnetic cores 2a, 2a, The eddy current generated in 2b becomes small.

As a result, the magnetic flux generated by the eddy current is reduced, and the responsiveness of the needle valve 10 is improved. In addition, the effect of reducing eddy currents is reduced in proportion to the number of slits.

Although the inner and outer magnetic cores 2a and 2b are divided into eight in the above embodiment, the present invention is not limited to this.

[0028]

[Effect of the device]

 As is apparent from the above description, according to the present invention, it is possible to reduce the eddy current simply by making a simple modification to the conventional configuration, the magnetic flux is reduced rapidly when the current is off, and the electromagnetic fuel injection is performed. The responsiveness of the valve is improved.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of an electromagnetic fuel injection valve according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along the line AA of FIG.

FIG. 3 is an explanatory diagram of a configuration of a part of FIG.

FIG. 4 is a vertical cross-sectional view of an example of a conventional electromagnetic fuel injection valve.

5 is a cross-sectional view taken along the line CC of FIG.

[Explanation of symbols]

1 ... Casing, 2 ... Sleeve, 2a ... Inner magnetic core,
2b ... outer magnetic core, 3 ... bobbin, 4 ... solenoid coil, 5 ... foreign matter removing strainer, 6 ... fuel passage, 7 ... spring coil, 8 ... movable iron core, 10 ... needle valve,
11 ... Valve seat, 12 ... Slit, 13 ... Eddy current path, 14 ... Spring stopper, 15 ... Cap nut, 2
3a ... Main body part, 23b ... Fixed iron core, 32,33 ... Eddy current path

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Kenji Hirose 4-1 Chuo 1-4-1, Wako-shi, Saitama Stock Research Institute Honda Technical Research Institute

Claims (2)

[Scope of utility model registration request] 1. A solenoid coil comprises a magnetic core wound substantially coaxially with a central axis thereof, a needle valve movable on the central axis, and a movable iron core coupled to the needle valve. By supplying current to the solenoid coil, the movable core is attracted to the magnetic core,
An electromagnetic fuel injection valve configured to inject fuel, wherein the magnetic core is divided by slitting in the central axis direction. 2. The electromagnetic fuel injection valve according to claim 1, wherein the magnetic core is at least one of magnetic cores located inside and outside the solenoid coil.