RU212704U1 - FUEL INJECTOR SOLENOID - Google Patents

Abstract

The fuel injector electromagnet includes a body part, hereinafter referred to as a base, on the end of which a magnetic circuit with an electric coil installed in it rests. The base has no precision internal ends. At the base, on the side opposite to the magnetic circuit, an annular cavity is made, having a groove on the inner side surface located in the diametral plane and having a cone shape in cross section, and annular grooves of arbitrary shape on the side surface of the central protrusion. The upper part of the base after assembling the electromagnet is poured with a compound to ensure that the compound flows into the annular grooves made on the inner side surface of the annular cavity and the side surface of the central protrusion in the annular cavity. The groove on the inner side surface of the annular cavity and the grooves on the side surface of the central protrusion of the annular cavity of the base have the same shape.

Description

A common type of modern fuel equipment is Common Rail type systems with electromagnetic fuel injectors (hereinafter referred to as injectors). Depending on the design features of the engines, the nozzles can be located outside or within the reach of atmospheric precipitation. In the latter case, raindrops or spray from the roadway may fall on them. According to the applicant's experience, this can lead to the penetration of the electrically conductive liquid to the magnetic circuit, causing corrosion and even short circuits.

A solenoid valve for a hydraulically controlled fuel injector is known, including a magnetic circuit with a winding and contacts placed in a separate part, a block having an electrical connection with the winding and filled with plastic during the manufacture of the block (US Pat. RU 2541483, publ. 20.02.2015. Bull. No. 5) . According to a well-known solution, the magnetic core with the winding is installed until it stops against the inner end of the sleeve. An insulator made in the form of a flat washer and a block with contacts are installed on the upper plane of the magnetic circuit, after which the upper part of the sleeve is rolled up.

The disadvantages of the known solutions include the possibility of moisture, for example, raindrops or splashes from the roadway through the place of rolling on the magnetic circuit. Due to the fact that, as a rule, the magnetic core is made of low-carbon steels, this can lead to intense corrosion.

The closest prototype of the claimed utility model in terms of essential features is an adjustable metering valve for a fuel injector of an internal combustion engine, including a body part, on the end of which the part with an electric coil installed is supported (US Pat. RU 2215177, publ. 27.10.2003. Bull. No. 30). The authors of the well-known solution call the part in which the electric coil is installed an annular magnetic core. In the literature and in practice, these parts are also called magnetic cores, so both terms will be used in the future. On the outer surface of the said body part, called the casing by the authors of the well-known solution, a groove is made into which a seal is installed in contact with the bore surface in the fuel injector body. The casing is made of a non-magnetic material and has an outer shoulder, on which a part rests, attracting it to the nozzle body and called the cylindrical cover by the authors of the well-known solution. Several versions are provided, including the execution of a casing with an inner end, on which an annular magnetic core rests. In this embodiment, the design is collapsible: the parts of the device placed in the casing can be removed from it, and the cylindrical cover can be freely removed. In another embodiment, the casing is a stepped cylindrical part, hollow at the ends, and the magnetic core rests on an additional part, called the disk by the authors of the well-known solution. The upper part of the disk and casing is filled with compound. At the same time, annular grooves are made on the outer surface of the disk filled with the compound for better fixation of the compound on the disk. Instead of a cylindrical cap, an additional ring nut is used to attract the device to the nozzle body. In this case, when assembling the device, the upper part of the casing is rolled onto the disk, the device becomes non-separable, the ring nut is non-removable from the device.

The disadvantages of the known solution include unsatisfactory manufacturability of the design, due to the need for precision machining of the inner end - when implementing one proposed option - or the impossibility of removing the ring nut for replacement in case of damage to the thread on it - when implementing another proposed option.

The technical problem to be solved by the proposed utility model is the creation of a fuel injector electromagnet design, the details of which do not have precision internal ends, which allows replacing the nut, through which it is attracted to the injector body, and providing reliable isolation of the magnetic circuit from rain drops or splashes from roadway.

The set technical problem is solved through the combined application of the following design measures:

- application in the design of the electromagnet of the fuel injector of the bearing part - the base - with a flat end, on which the magnetic circuit rests;

- execution in the base from the side opposite to the magnetic circuit of the annular cavity for accommodating the electrical leads of the coil and their connections with the contacts;

- execution on the inner side surface of the annular cavity of the base from the side opposite to the magnetic circuit, a groove located in the diametrical plane and having a cone shape in cross section;

- execution on the side surface of the central protrusion of the annular cavity of the base from the side opposite to the magnetic core, annular grooves of arbitrary shape;

- pouring the upper part of the base with a compound to ensure that the compound flows into the annular grooves made on the inner side surface and the side surface of the central protrusion of the annular cavity of the base from the side opposite to the magnetic core.

A novelty in the proposed fuel injector electromagnet is the presence on the inner side surface of the annular cavity of the base on the side opposite to the magnetic circuit, a groove located in the diametrical plane and having a cone shape in cross section.

The indicated feature is new, significant and industrially feasible and is aimed at solving the technical problem set by the utility model.

The electromagnet of the fuel injector proposed as a utility model is illustrated by the drawing (Fig.) and includes a base 1 and a magnetic circuit 2. On the inner side surface of the annular cavity of the base 1, a groove 11 is made in the diametrical plane, having a cross-sectional shape of a cone with rounded corners. On the side surface of the central protrusion of the annular cavity of the base 1 in the diametrical plane, annular grooves 12 of arbitrary shape are made. To increase the durability of the cutting tool, the grooves 11 and 12 may have rounded corners. The value of the radii of curvature and the depth of the grooves 11 and 12 are not subject to protection in this application. The number of grooves 12 is determined by the protrusion of the central protrusion of the base 1 above the surface of the inner end 13.

In FIG. as an example, not excluding other versions, the design of the base with four annular grooves 12 is shown.

End face 13 is not precise and does not require high-precision equipment for processing. Base 1 has no precision internal ends.

An annular shoulder 14 is made on the outer side surface of the base 1, on the surface 15 of which a nut 4 rests, which attracts an electromagnet to the fuel injector body (not shown in the figure). The outer diameter of the shoulder 14 is the largest - overall - diameter of the electromagnet. This provides free installation-removal of the nut 4 and its replacement, if necessary.

After assembling the electromagnet of the proposed design, including - fixing the magnetic circuit 2 to the base 1, performed by any method known from the prior art, and connecting the electrical leads to the contacts (not marked in the figure) - the upper part of the base 1 is poured with compound 3 to provide the specified outer form. In this case, the compound 3 enters the grooves 11 and 12 and cures there.

The presence of grooves 11 and 12 not only increases the area of contact of the compound 3 with the surface of the base 1, thereby increasing the strength and tightness of the connection due to adhesion, while playing the role of a kind of labyrinth seal and, accordingly, reducing the likelihood of rain drops and splashes from the roadway on magnetic circuit 2. The presence of grooves 11 and 12 ensures the strength of the structure in the axial direction, since the compound 3 in the grooves 11 and 12 after curing works on the cut.

Proposed as a real utility model, the fuel injector electromagnet operates as follows.

The electromagnet is installed in the fuel injector and secured with nut 4, after which the control harness from the electronic control unit (not shown in the figure) is connected to the injector. If, for some reason, the nut has damaged threads, it can be easily replaced.

When control signals are applied to the electromagnet, the nozzle starts to work. Depending on the design features of the engine on which it is installed, the electromagnet may be within reach of raindrops and spray from the roadway. Drops and/or splashes can fall on the top of the fuel injector solenoid - compound 3 accumulate in the annular gap 5 - between nut 4 and compound 3.

Due to the presence of grooves 11 and 12 on the base and the compound 3 cured in them, moisture from the annular gap 5 cannot get to the magnetic circuit 2 and cause malfunctions of the electromagnet and the nozzle as a whole.

The technical result of the implementation of the proposed utility model is to increase the manufacturability of the design of the fuel injector electromagnet while increasing its reliability.

The fuel injector electromagnet proposed as a real utility model has been put into mass production at the Altai Precision Products Plant.

Claims (2)

1. An electromagnet of a fuel injector, including a body part, hereinafter referred to as a base, on the end of which a magnetic circuit with an electric coil installed in it rests, characterized in that at the base, on the side opposite to the magnetic circuit, an annular cavity is made with a central protrusion, on the inner side annular cavity, a groove is made, located in the diametrical plane and having a cone shape in cross section, annular grooves are made on the lateral surface of the central protrusion, the upper part of the base after the assembly of the electromagnet is made with the possibility of filling with a compound to ensure that the compound flows into the annular grooves made on the inner side surface of the annular cavity and on the side surface of the central protrusion in the annular cavity. 2. The fuel injector electromagnet according to claim 1, characterized in that the groove on the inner side surface of the annular cavity and the grooves on the side surface of the central protrusion of the base annular cavity have the same shape.

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