JPS62351B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electromagnet for a fluid pressure control valve, and more particularly for actuating a control valve for controlling the pressure of a fluid pressure medium acting on an injection valve of a fuel injector for a diesel engine. Regarding electromagnets that cause

As a prior art, there is an electromagnet for a fuel injector as disclosed in Japanese Unexamined Patent Publication No. 53-120017. This electromagnet is placed in the fuel injector, and the armature is in the form of a flat disk.
This flat disc also serves as a valve, so it is contained within the fuel. The electrically energized conductors are placed in slots in the surface of the magnetic core, but this slotted surface is only present on one side of the armature disc. . Therefore, this electromagnet only applies magnetic force in one direction. In the opposite direction the disk is adapted to be actuated by a spring.

In order to achieve good operation using an armature consisting of a flat disk, this disk must be rigid. If the disc is strong enough to bend during operation, satisfactory operation cannot be expected. However, imparting the desired rigidity to a flat disk increases the weight of the disk. The disadvantage of increasing the weight of the disc is that it becomes difficult to move this disc very quickly. Unless the weight of the members constituting the armature is made as light as possible, the responsiveness of the armature as an electromagnet for operating a fuel injection nozzle for a diesel engine will deteriorate.

Furthermore, in the above-mentioned electromagnet in the prior art,
Although the disks are actuated in opposite directions by means of springs, such an arrangement is also not preferred. This is because if the spring is destroyed, the fuel injection nozzle will become inoperable.

The present invention aims to overcome the above-mentioned drawbacks of the prior art, and it is possible to apply almost the same magnetic force to the armature as the electromagnet of the prior art, and the stiffness of the armature is also almost the same as that of the prior art. I can do it to a certain extent,
Furthermore, by including an armature that weighs about 1/7 to 1/10 of the weight of a conventional armature, the electromagnet can be configured to operate this armature extremely quickly. It is intended that Furthermore,
The armature is actuated in either direction by passing a current through an electrically biased conductor, rather than using a spring to move it in one direction as in the prior art. It is intended not to be adopted.

According to the invention, an electromagnet for actuating a control valve for controlling the pressure of a fluid pressure medium acting on an injection valve of a fuel injector for a diesel engine, the electromagnet carrying an electrically energized conductor. a magnetic core movable relative to the magnetic core and connected to the control valve, the armature comprising a thin-walled hollow cone with an obtuse angle; a first air gap is formed between an inner surface of the cone and an adjacent surface of the magnetic core; a second air gap is formed between an outer surface of the cone and an adjacent surface of the magnetic core; The surfaces of the magnetic cores are parallel to the inner and outer surfaces of the cone, respectively, and the conductive wire is disposed in at least two slots formed in the surface of each magnetic core, and the conductive wire is disposed in at least two slots formed in the surface of each magnetic core. There is provided an electromagnet for a control valve for a fuel injector, characterized in that the hole is symmetrical with respect to the axis of the cone.

By constructing the armature as a thin-walled hollow cone with an obtuse angle, its weight can be significantly reduced while maintaining the desired stiffness, thus allowing ultra-high speed movement of the armature and improving its response. It can be used as a high-performance electromagnet. Furthermore, grooves were provided on both surfaces of the respective magnetic cores parallel to the inner and outer surfaces of the cone, and electrically energized conductors were placed therein, so that the armature could be connected to one of the magnetic cores. When the magnetic core is actuated so as to be attracted to the surface of the other magnetic core, a current is passed through the conductor in the groove provided on that surface. The armature can be electrically reciprocated in either direction by passing a current through it.

The cross-section for the magnetic flux accounts for only a small portion of the total flux, i.e. half of the total flux in the case of two slots and 1/1/2 in the case of three slots.
3, the resulting magnet has a rigid and extremely lightweight armature. Leakage flux occurs only near the outermost and/or innermost slots. Since the magnetic flux path is extremely short, iron losses are minimal.
The same magnet mass is fully available for the windings associated with the two directions of magnet movement. The magnet according to the invention is therefore suitable for very rapid reciprocating movements, such as those required in controlling the movement of the injector valves of diesel engine fuel injectors.

Practical embodiments of the invention will now be described in greater detail with reference to the accompanying drawings.

In FIG. 1, a fuel injector 50 has a fuel supply duct 53 in a body 52 which is located in a cylinder head 51 (not shown in detail) of a diesel engine and which extends to a chamber 54.
The injection valve 55 disposed within the main body 52 has a first
It cooperates with the valve seat surface in the valve body 52 at the end 49 which is the bottom end in the figure and forms a sealing surface. The central duct 48 connects with the chamber 54 below the injection valve end 49 in FIG.
When the fuel is opened, the fuel is injected into the combustion chamber 46 through the duct 47 in finely divided form.

The injection valve 55 is located at the top end in FIG.
It has a piston 56 that slides within it.

A hydraulic pipe line 58 is connected to the cylinder chamber 57.
Hydraulic medium for operating the injection valve 55 is supplied through the hydraulic conduit from a hydraulic source (not shown). A line 59 branches off from line 58 and has a control valve 60 controlled by an electromagnet 61 whose structure is shown in greater detail in FIG. When the control valve 60 is in the position shown, the force exerted on the piston 56 by the pressure medium supplied through the line 58 is determined to keep the injection valve 55 closed. In order to inject fuel into the combustion chamber 46, the electromagnet 61 is connected to the control valve 6.
0 is unseated from the valve seat surface in conduit 59, so that the pressure generated by the hydraulic medium in cylinder 57 is relieved and the pressure of the fuel in said chamber 54 pushes up injector 55, causing its As a result, fuel flows freely through central duct 48 and duct 47.

In FIG. 2, the magnet 61 has a magnetic core that is substantially disk-shaped and is divided into two parts 1, 2 having a circular contour. Second
The surface of the top part 1, which is at the bottom in the figure and which defines an obtuse conical surface, is formed with two slots 3, 4, and said slots extend along the axis 9--9 of the cone.
concentric with and open at the bottom, having an undercut cross-section and serving to receive a winding of the energizing conductor. Similarly, the surface of part 2, which in FIG. 2 is at the top and defines a conical surface having the same cone angle as that of part 1, is formed with two concentric slots 3', 4'. These slots are open at the top, concentric with the cone axis 9--9, have an undercut cross-section, and receive the biasing winding. The distance between the slots 3, 4 or 3', 4' and the cone axis 9-9 is such that said slots extend substantially over the entire air gap between the mutually parallel conical surfaces of the two parts 1 and 2. It is determined that the distribution is uniform. As is clear from FIG. 3, the slots 3, 4 communicate with each other by two radial slots 5, 6, and so do the slots 3', 4'. A conductor 7, the passage of which is shown in dashed lines in FIG. 3, extends from the outside through the outer part of the radial slot 5 and then passes through the slot 4 many times over its entire circumference;
It then enters the slot 3 through the inner part of the slot 5. The conductor also passes through the slot 3 several times over its entire length, after which it exits the magnetic core via the radial slot 5. Further, the arrows in FIG. 3 indicate the direction in which the current flows.

An armature 8 consisting of a thin-walled hollow cone with an obtuse angle is arranged between parts 1 and 2. The ratio of the wall thickness of the cone to the outer diameter of the cone is less than or equal to 0.1. The armature 8 is formed with a number of apertures 10, the axes of which extend parallel to the cone axis 9-9 between the slots 3 and 4 and between the slots 3' and 4'. It is made to be. Therefore, aperture 1
The axis of 0 is located on a circle. The diameter of the opening 10 is at most 20% of the pitch of the slot. Near the cone axis and the outer edge of the armature 8,
Each of the parts 1, 2 has a ring 12, 13 and 12', 13' respectively. The ring is part 1,
2, extending into the air gap between the two parts and serving as an abutment for the reciprocating movement of the armature. In the illustrated condition, said armature abuts the two bottom rings 12', 13' in part 2, with a gap S of a few hundredths of a millimeter (the second
) remains between the underside of the armature and the top of part 2, thus preventing the armature from sticking. The rings 12, 12', 13 and 13' have over their respective circumferences a number of orifices in the form of radial notches 14, 15, respectively, which cooperate with the opening 10 during movement of the armature to take in and out air. It is formed. Since the opening 10 provided in the armature 8 is located exactly centered between the two adjacent slots and has a relatively reduced diameter, the density of the magnetic flux at the center is Because it is small, disturbances in the magnetic flux are minimal.

The magnetic cores 1, 2 are formed around respective bores 16, 16' through which the rods 19 extend. The rod 19 has the armature 8 fastened between the expanded diameter portion 18 of the rod and the collar 17.
It is rigidly attached to the armature 8. A spring spider 20 engages the top end of portion 18 and a spring spider 21 engages the bottom end of collar 17, each spring spider having a number of radial arms. The spring spider is rigidly fixed to the rod 19 by nuts 23 screwed into both ends of the rod. The outer end of the arm of the top spider 20 presses against a cylindrical sleeve 22 enclosing the two parts 1 and 2 and presses against the cup spring 2.
4 and a retaining ring 28. The outer end of the bottom spider 21 also presses against the sleeve 22 between an intermediate ring 25 holding the part 2 and a retaining ring 26 fitted in an annular groove provided in the sleeve 22.

Spiders 20, 21 are made of non-magnetic material, such as stainless steel or beryllium bronze. The only function of these spiders is to guide and center the armature 8.
The spring forces associated with this are negligible.
The moving parts of control valve 60 (FIG. 1) are directly related to rod 19, but this feature is not shown in detail.

In FIG. 4, the slots can extend helically within the core portions 1 and 2 instead of being concentric. In this case, the innermost ends of the two said slots are interconnected by a radial slot 30. The extension of the conductive wire 7 to be energized is indicated by a chain line. More than two slots can be provided.

In FIG. 5, three concentric slots are provided in the core parts 1, 2, the passage of the conductor is different from that in FIG. 3, but as in FIG.
Indicated by a dashed line.

What is important with regard to the passage of the conductor in all the embodiments described above is that the current flows flowing in mutually adjacent slots must be directed in opposite directions.

When the armature is in the top position and abuts the rings 12 and 13, a gap equal to the gap S exists between the underside of the section 1 and the top of the armature 8. A spacer ring 29 between parts 1 and 2, ie a spacer ring which engages the sleeve 22 at its outer periphery, determines the spacing between rings 13 and 13' and thus between parts 1 and 2.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a fuel injector having an electromagnetically controlled injection valve according to the invention;
Figure 2 is an axial section through the reciprocating magnet, Figure 3 is a simplified view of one of the two parts of the core, seen from the armature side, Figures 4 and 5 are different. 3 is a view similar to FIG. 3 of a magnetic core with a slotted pattern; FIG. DESCRIPTION OF SYMBOLS 1...Magnetic core part, 2...Magnetic core part, 3...Groove hole, 4...Groove hole, 5...Radial direction groove, 6
... Radial groove, 7 ... Conductor, 8 ... Armature, 9 ... Rod, 10 ... Opening, 12 ... Ring, 13 ... Ring, 14, 15 ... Notch,
17...Color, 18...Part, 20...Spider, 21...Spider, 22...Sleeve, 23
... Nut, 24 ... Cup spring, 25 ... Intermediate ring, 26 ... Retaining ring, 28 ... Retaining ring, 29
...Spacer ring, 30... Groove, 46...
Combustion chamber, 47...Duct, 48...Duct, 49
... Injection valve end, 50 ... Fuel injector, 51 ...
Cylinder head, 52...valve body, 54...chamber,
55... Injection valve, 56... Piston, 57... Cylinder chamber, 58... Branch pipe line, 59... Pipe line, 6
0...control valve, 61...electromagnet.

Claims (1)

[Scope of Claims] 1. An electromagnet for actuating a control valve for controlling the pressure of a fluid pressure medium acting on an injection valve of a fuel injector for a diesel engine, the electromagnet carrying an electrically energized conductor. a magnetic core movable relative to the magnetic core and connected to the control valve, the armature comprising a thin-walled hollow cone with an obtuse angle; A first air gap is formed between an inner surface of the cone and an adjacent surface of the magnetic core, and a second air gap is formed between an outer surface of the cone and an adjacent surface of the magnetic core. , the surfaces of the magnetic cores are respectively parallel to the inner and outer surfaces of the cone, and the conductive wires are disposed in at least two slots formed in the surface of each of the magnetic cores; An electromagnet for a control valve for a fuel injector, characterized in that the slot is symmetrical with respect to the axis of the cone.