Injector with integrated filter and method for assembling the injector

Abstract

To provide an injector which is improved in assembling performance.SOLUTION: An injector for injecting liquid includes: a closing element (2) for opening and closing at least one penetration hole (3) which is formed at a sealing seat (4); a restoration element (5) which is arranged in order to press the closing element (2) to the sealing seat (4) so as to seal the sealing seat by making a restoration force for restoration and a closing force act on the closing element (2); a filter (6) for filtering liquid to be injected; and a sleeve (7) arranged at an action connecting part between the filter (6) and the restoration element (5) in an axial line direction (X-X) of the injector. In this case, the restoration element (5) is supported by the sleeve (7), and a final position of the restoration element (5) in the axial line direction is decided by a position of the filter (6) in the injector.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an injector for an internal combustion engine for injecting a liquid, particularly fuel or urea or water, and a method for assembling the injector.

Background Art

[0002] Injectors for internal combustion engines are known in the art in various configurations. In the case of fuel injectors, for example, fuel is sprayed through fine through-holes. In this case, recent injectors are manufactured with extremely high precision and must be protected from damage and wear caused by particles in the fuel. For this reason, filters are usually used. It is known to incorporate the filter directly into the injector, preferably into the fuel supply area within the injector. Thereby, the components of the injector can be protected from damage caused by particles in the injected liquid. If the injector is adjusted with respect to the injection quantity already before the final assembly and then further finishing assembly is carried out (for example, to form a plug extrusion coating for an electrical contact part), these assembly steps enlarge the tolerance for one time, and as a result, particularly strict requirements for the tolerance cannot be guaranteed.

Summary of the Invention

[0003] In contrast, the injector according to the present invention, having the configuration of claim 1, has the advantage of maintaining small flow tolerances for the liquid to be injected, because the filter incorporated within the injector can be precisely positioned. Furthermore, the positioning of the filter allows for precise adjustment of the return force and closing force of the return element of the injector, which closes the through-hole in the injector with a closing element at the sealing seat. This is achieved according to the present invention by providing a sleeve positioned at the working coupling between the filter and the return element in the axial direction of the injector. In this case, the return element is supported directly or indirectly by the sleeve. The final axial position of the return element is determined by the position of the mounted filter within the injector, because the position of the filter also determines the position of the sleeve on which the return element is supported directly or indirectly. In this case, the filter is preferably fixed in the injector by pressure fitting. Particularly advantageous, the sleeve is also held in place by a fixed component by pressure fitting within the injector.

[0004] A particular advantage of the present invention is that the filter functions as both a robust adjustment element for dynamic quantities and a protective measure against particles, and can be inserted in an early assembly process before carrying out high-contamination-risk processes such as plastic extrusion coating of injectors.

[0005] The dependent claims illustrate further advantageous configurations of the present invention.

[0006] Preferably, the sleeve is in direct contact with the return element and the filter. This keeps the number of parts as low as possible and allows for quick and easy assembly. Furthermore, this avoids the addition of manufacturing tolerances that would have an undesirable effect on the sleeve's final position and thus on the pre-tensioning force of the return element.

[0007] The filter is formed in a pot shape, particularly advantageously having a bottom region and side regions, with the bottom region positioned in the direction of the sleeve. This allows for a robust injector structure and enables the filter mounting tool to be positioned specifically inside the pot-shaped filter, thereby allowing the mounting tool to contribute to reinforcing the filter during installation.

[0008] The filter preferably does not have filtration holes in the bottom region. Therefore, the bottom region is preferably made from a solid material, which further improves the rigidity of the filter. In this case, the fuel flows into the pot-shaped interior of the filter and then passes through the filter via the filtration holes in the side region.

[0009] For particularly cost-effective manufacturing, filters are preferably manufactured entirely from plastic. Alternatively, filters are manufactured from plastic with a reinforcing encapsulant. The reinforcing encapsulant is preferably a metal encapsulant. In this case, the filter can be manufactured, for example, by injection molding, together with the reinforcing encapsulant as an insert member in the injection molding process.

[0010] Particularly advantageous, the filter further has a reinforcing ring at the end opposite the bottom region. Particularly advantageous, the reinforcing ring is part of a reinforcing encapsulation. In this case, preferably, the reinforcing encapsulation has, in addition to the reinforcing ring, a plurality of axially extending fins.

[0011] Preferably, the reinforcing encapsulant is in direct contact with the sleeve. This allows for particularly precise positioning of the sleeve within the finally assembled injector without damaging the filter during assembly.

[0012] More advantageously, at least one, and more particularly two, slits are provided in the bottom region of the filter to provide a fluid coupling to the inner region of the sleeve. The two slits are preferably arranged to face each other.

[0013] The present invention further relates to a method for assembling an injector comprising a closing element, a return element, a sleeve, and a filter. In this case, the filter is installed in the injector in a single assembly step as follows: the installation position of the filter also defines the installation position of the sleeve, and defines the pre-tensioning force of the return element on the closing element within the closed injector. In this way, the return force and closing force of the return element on the closing element can be adjusted depending on the position of the filter.

[0014] Particularly advantageous is that the filter is installed in the injector using a stepped mounting tool. The stepped mounting tool preferably has first and second cylindrical regions with different diameters, the first cylindrical region being located inside the filter and the second cylindrical region being located at the end of the filter opposite the bottom region. Thus, the stepped mounting tool engages simultaneously with the bottom region and flange of the filter. This ensures that the filter is installed without damage.

[0015] Next, an advantageous embodiment of the present invention will be described in detail with reference to the attached drawings. [Brief explanation of the drawing]

[0016] [Figure 1] This is a schematic cross-sectional view of an injector according to one advantageous embodiment of the present invention. [Figure 2] Figure 1 is a schematic perspective view of the injector filter. [Figure 3] This is a schematic partial cross-sectional view illustrating the mounting method of the present invention. [Modes for carrying out the invention]

[0017] Next, an injector 1 according to a first advantageous embodiment of the present invention will be described in detail with reference to Figures 1 to 3.

[0018] The injector 1 is an injector for injecting a liquid, and in this embodiment, it is formed as a fuel injector.

[0019] The injector 1 includes a closing element 2 for opening and closing a plurality of through holes 3. In this case, the closing element 2 seals at a sealing seat 4 provided at the first end of the injector 1.

[0020] The injector 1 further includes a return element 5 installed to provide a return force F to the closing element 2 when the injector is open and to provide a closing force to hold the injector in a closed state. As is clear from FIG. 1, the closing element 2 is a hollow valve needle 2a having a spherical body 2b that seals at the sealing seat 4.

[0021] FIG. 1 shows the injector in a closed state.

[0022] Furthermore, the injector 1 includes a sleeve 7 for flowing fuel in the direction of the closing element 2 and a filter 6.

[0023] The filter 6 can be seen in detail from FIGS. 2 and 3. The filter 6 basically has a pot-like form and includes a bottom region 60, a side region 61, and a flange 62.

[0024] As is clear from FIG. 1, the filter 6 is arranged such that the bottom region 60 faces in the direction of the closing element 2. As a result, fuel flows into the interior of the pot-like filter at the supply end of the injector and flows out of the filter through the side region 61 where the filter cloth is arranged. Therefore, even if solid substances are contained in the fuel, the solid substances can be filtered when entering the injector 1 by the filter 6 and can be collected in the pot-like interior of the filter 6.

[0025] The injector 1 further includes an actuator 9, which is a magnetic actuator in this embodiment. Further, an extrusion coating portion 16 is provided, and the extrusion coating portion is installed to arrange an electric plug (not shown) for supplying electricity to the actuator 9.

[0026] In this case, the function of the injector 1 is as follows. When the actuator 9 is energized, the closing element 2 is pulled against the spring force of the return element 5 in the direction of the stationary component 8 inside the injector, and at this time, the sphere of the closing element 2 is lifted from the sealing seat 4, so that fuel can flow out through the through hole 3.

[0027] The flow path of fuel when the injector is open is shown by arrows A to E in FIG. 1. The fuel flows into the pot-shaped interior of the filter 6 and flows out of the filter 6 through the side region 61 (arrow B), thereby implementing the filtering process. The fuel further flows into the interior of the sleeve 7 as suggested by arrow C and into the interior of the hollow closing element 2 by the cylindrical return spring 5. In this case, the closing element 2 has a plurality of side openings 2c in the end region directed towards the sealing seat 4, and a second filter 15 is arranged in these side openings, so that the fuel can flow out of the interior of the closing element 2 as suggested by arrow E. When the closing element 2 is lifted from the sealing seat 4 at this point, the fuel can flow into the through hole 3 past the sphere of the closing element 2.

[0028] To ensure the reliable and accurate function of the injector 1, both the force F of the return element 5 that enables the return of the closing element 2 to the closed starting position, and the closing force of the return element 5 that holds the closing element 2 in the closed position at the sealing seat 4, must be precisely adjusted. In this case, as is clear from Figure 1, the return element 5 is supported at the first end by the stepped portion 2d of the closing element 2, and at the second end by the sleeve 7. Thus, the position of the sleeve 7 determines both the closing force and the return force of the return element 5. In this case, a press-fit portion 70 is provided between the sleeve 7 and the stationary component 8. As a result, the position of the sleeve 7 in the axial direction XX is adjusted using the filter 6.

[0029] As is clear from Figures 2 and 3, the filter 6 includes a bottom region 60 made of a solid material, a side region 61, and a flange 62 directed radially outward. The filter 6 is a composite member and includes a plastic region and a reinforcing region made of a material having higher rigidity than the plastic region.

[0030] In this case, the bottom region 60 is formed entirely of plastic and does not have through holes or anything similar. The filter 6 includes a reinforcing encapsulant 10 to significantly increase the rigidity of the filter 6, particularly in the axial direction XX. The reinforcing encapsulant 10 is preferably made of metal and includes a reinforcing ring 11 provided on the flange 62 and a plurality of fine strips, in this embodiment four fine strips 12, extending in the axial direction XX from the reinforcing ring 11. This means that only one insert member 10 is required for the filter 6. Preferably, the insert member is bonded to or manufactured integrally with the filter encapsulant 13, or, for example, a metallic filter cloth. The filter 6 is then partially extruded and coated with plastic 14, so that further regions of the filter 6 are manufactured from plastic.

[0031] As is clear from Figures 2 and 3, the bottom region 60 has two wide slits 63 facing each other. In this case, the slits 63 are used to transfer the filtered fuel into the sleeve 7, as indicated by arrow C in Figure 1.

[0032] In this way, a particularly robust filter 6 can be provided, which is installed to adjust the axial position of the sleeve 7, and thus to adjust the closing force and return force of the return element 5. As is evident from Figure 3, a tool 20 may be provided for installing the filter 6 into the injector 1. In this case, the tool 20 has a protruding portion 21 inserted into the pot-shaped interior of the filter 6 and a stepped portion 22 that engages with the flange 62 of the filter 6. At this time, the filter is positioned in the sleeve 7 already installed in the injector by the pressurized input P, ​​and the end position of the sleeve 7 in the axial direction XX is determined. At this time, the filter 6 contacts the end of the sleeve 7 facing the filter with its bottom region 60, allowing the sleeve 7 to be displaced to a predetermined end position in the axial direction XX.

[0033] The reinforcing encapsulant 10, made of metal, may be cold-forged, for example. In this case, a second press-fit portion 64 is formed between the filter 6 and the housing portion 18. Therefore, by using a tool 20 that acts simultaneously on both the bottom region 60 and the flange region 62 when installing the filter 6, installation without damage can be achieved, and as a result, the flow rate of fuel through the filter 6 does not change. This solves a problem that frequently occurs at the current level of technology, because damage or deformation due to excessive installation force often caused the flow rate through the filter to not correspond to the planned target value. The superior configuration of the filter 6 as a composite member with the reinforcing encapsulant 10 ensures that undesirable deformations that would change the flow rate through the filter 6 do not occur during injector operation. [Explanation of Symbols]

[0034] 1 Injector 2. Closure element 3 Through holes 4 Sealing seat 5. Recovery elements 6 filters 7 sleeves 10 Reinforcement inclusions 11 Reinforcement ring 12 Fine strips 14 Plastic 20 Tools (Installation Tools) 60 Bottom area of ​​the filter 61 Side region of the filter 62 Filter flange 63 slits XX Injector axial direction

Claims

1. In an injector for spraying liquid, A closing element (2) for opening and closing at least one through hole (3) provided in the sealing seat (4), A return element (5) is installed to apply a return force and a closing force to the closing element (2) to press the closing element (2) against the sealing seat (4) to seal it, A filter (6) for filtering the liquid to be sprayed, A sleeve (7) is positioned in the axial direction (X-X) of the injector at the operational coupling between the filter (6) and the return element (5), Includes, The return element (5) is supported by the sleeve (7), The final axial position of the return element (5) is determined by the position of the filter (6) within the injector. The filter (6) is formed in a pot shape with a bottom region (60) and a side region (61), and the bottom region (60) is positioned in the direction of the sleeve (7). In order to provide a fluid coupling portion for liquids extending from the outer region of the filter (6) to the inner region of the sleeve (7), the bottom region (60) of the filter (6) has at least one slit (63). Injector.

2. The injector according to claim 1, wherein the bottom region (60) is provided with two slits (63), and the two slits face each other.

3. In an injector for spraying liquid, A closing element (2) for opening and closing at least one through hole (3) provided in the sealing seat (4), A return element (5) is installed to apply a return force and a closing force to the closing element (2) to press the closing element (2) against the sealing seat (4) to seal it, A filter (6) for filtering the liquid to be sprayed, A sleeve (7) is positioned in the axial direction (X-X) of the injector at the operational coupling between the filter (6) and the return element (5), Includes, The return element (5) is supported by the sleeve (7), The final axial position of the return element (5) is determined by the position of the filter (6) within the injector. The filter (6) is an injector comprising a reinforcing encapsulant (10) which includes a reinforcing ring (11) and a number of fine strips (12) extending from the reinforcing ring (11) in the axial direction (X-X).

4. The injector according to claim 3, wherein the reinforcing encapsulant (10) is in direct contact with the sleeve (7).

5. The injector according to claim 3 or 4, wherein the filter (6) is formed in a pot shape with a bottom region (60) and a side region (61), and the bottom region (60) is arranged in the direction of the sleeve (7).

6. The injector according to claim 1 or 5, wherein the bottom region (60) is formed without filtration holes.

7. The injector according to any one of claims 1 to 6, wherein the sleeve (7) is in direct contact with the return element (5) and the filter (6).

8. The injector according to any one of claims 1 to 7, wherein all or part of the filter (6) is made of plastic.

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