EP1825135B1 - Injection valve - Google Patents

Description

State of the art

The invention relates to an injection valve, in particular for fuel injection systems of internal combustion engines in motor vehicles, according to the preamble of claim 1.

In a known injection valve of the magnetic pot with Spulentragerund wound thereon solenoid is pushed onto the sleeve-shaped housing portion and placed with its pot opening on a lower housing part which defines a valve seat carrier on the sleeve-shaped housing portion. The bobbin is sitting with the inner cylinder wall of its carrier body directly on the sleeve-shaped housing portion and is surrounded by the pot wall of the magnet pot with air clearance. The magnet pot has a pot socket which continues axially on the bottom of the pot and is integral with the bottom of the pot and which surrounds the sleeve-shaped housing part. Outside on the spigot is a circumferential labyrinth pierced by machining. At the axial distance from the pot socket a second labyrinth is introduced by machining on the sleeve-shaped housing part. The sleeve-shaped housing portion and the pot socket are enveloped by a plastic extrusion, on which a plug for connecting the solenoid to a mating connector is formed. Due to the two labyrinths on which the plastic is shrunk, the magnetic coil is sealed against environmental influences, so that under certain environmental conditions forming salt mist does not occur at the transition points between the plastic of the plastic injection and the metal of the sleeve-shaped housing part and along the metallic walls to the Solenoid reach and can cause electrical damage there. Since the labyrinths can only be produced by machining, the production of these labyrinths is very costly, which is not negligibly reflected in the manufacturing costs of the injection valve.

From the US 2001/0002681 A1 is already an injection valve, in particular for fuel injection systems of internal combustion engines in motor vehicles, known which comprises a sleeve-shaped housing portion exhibiting valve housing and arranged on the housing portion electromagnet. The electromagnet comprises a coil carrier with a carrier body and these front side limiting carrier flanges and a wound on the carrier body magnetic coil. Furthermore, the injection valve has a magnetic cup receiving the coil carrier as outer pole of the electromagnet with a pot wall and a one-piece, the housing portion with a bottom opening enclosing the pot bottom. The intermediate space between the inner wall of the pot wall of the magnet pot and the outer circumference of the magnet coil is filled with an annular plastic web which is part of a plastic extrusion and merges into an electrical connector on the axial side opposite the annular plastic web. The plastic extrusion is thereby both completely independent of the bobbin produced and mounted. The magnetic coil is a preassembled module, which consists of the coil carrier and the actual winding of the solenoid. Only after the assembly of this assembly on the valve housing, the filling of the above-mentioned gap can be made around the solenoid with a plastic injection molding machine.

From the EP 0 487 199 A1 is already an injection valve, in particular for fuel injection systems of internal combustion engines in motor vehicles, known which comprises a sleeve-shaped housing portion exhibiting valve housing and arranged on the housing portion electromagnet. The electromagnet comprises a coil carrier with a carrier body and these front side limiting carrier flanges and a wound on the carrier body magnetic coil. Furthermore, the injection valve has a coil carrier receiving two-part magnet pot as outer pole of the electromagnet with a U-shaped yoke and a housing portion enclosing a bottom opening bottom part. The coil carrier with wound magnetic coil is on all sides completely enclosed by a one-piece plastic sheath, so that it is virtually encapsulated in the plastic completely.

(Continued on page 2 with the section "Benefits of the invention" of the originally filed application documents)

From the JP 2002-4013 A is already an injection valve, in particular for fuel injection systems of internal combustion engines in motor vehicles, having a sleeve-shaped housing portion having a valve housing and a disposed on the housing portion electromagnet, a coil carrier with carrier body and this end face limiting carrier flanges, wound on the carrier body and a coil bobbin receiving magnetic pot with pot wall and thus one-piece, the housing portion having a bottom opening enclosing pot bottom, known. The bobbin is arranged in the magnet pot so that the remote from the magnet coil inner wall of the support body is pushed onto the housing portion, wherein the bobbin is wound with wound magnetic coil with a one-piece plastic jacket, the the pot wall of the magnet pot facing lateral surface of the magnet coil and carrier flanges and at least The covered from the bottom of the pot carrier flange covered. The magnet pot engages with its bottom of the pot, the coil carrier immediately adjacent to its lower support flange, and the plastic jacket extends to the pot wall of the magnet pot facing lateral surface to the bottom of the pot, where it rests.

Advantages of the invention

The injection valve according to the invention with the features of claim 1 or the features of claim 2 has the advantage that an equally good seal of the solenoid is achieved against damaging environmental influences with a lower manufacturing cost. The injection valves with the features of claim 2 have the additional advantage that the outer diameter of the electromagnet can be kept smaller with the same magnetic power. The formed on the bobbin labyrinth in the injector according to claim 2 is easy to manufacture manufacturing technology and is formed in the manufacture of the bobbin same with.

The measures listed in the further claims advantageous refinements and improvements of the claim 1 and in claim 2 injection valve are possible.

According to a preferred embodiment of the invention, the magnet pot, the coil support carrying the magnetic coil in the magnet cup, the coil integrated in the plastic jacket for closing the magnetic circuit and the plug molded onto the plastic jacket for contacting the magnet coil form a prefabricated mounting unit. This mounting unit can be manufactured and delivered outside the assembly line for the injection valve, for example by a supplier. Thus, the cycle time required for the injection molding of the plastic sheath is not coupled to the cycle time within the assembly line of the injection valve.

drawing

Fig. 1

ausschnittweise einen Längsschnitt eines Einspritzventils,

Fig. 2

eine vergrößerte Darstellung des Ausschnitts II in Fig. 1 mit einer Modifikation des Einspritzventils,

Fig. 3

jeweils ausschnittweise einen Halblängsschnitt

und 4

eines Einspritzventils gemäß zweier weiterer Ausführungsbeispiele.

The invention is explained in more detail with reference to embodiments illustrated in the drawings in the following description. Show it:

Fig. 1

partial section of a longitudinal section of an injection valve,

Fig. 2

an enlarged view of the section II in Fig. 1 with a modification of the injection valve,

Fig. 3

each partially a half-length section

and 4

an injection valve according to two further embodiments.

Description of the embodiments

This in Fig. 1 In longitudinal section of a section schematically sketched injection valve is preferably used in fuel injection systems of internal combustion engines in motor vehicles. It has a valve housing 11 with a thin-walled, sleeve-shaped, upper housing portion 12, whose free end forms a connecting piece 34 for the fuel inlet, and a integrally connected thereto, the lower housing portion 13 which is formed as a valve seat carrier with valve opening. Alternatively, the valve seat carrier can also be used as a separate component in the lower housing section 13. The connecting piece 34 encloses a fuel inlet channel 36, which is closed with a fuel filter 34 and continues through the lower housing portion 13 up to the valve opening. On the sleeve-shaped, upper housing portion 12, an electromagnet 14 is arranged. The electromagnet 14 consists of a coil support 15, a magnetic coil wound thereon 16, a magnetic pot 17, in which the coil carrier 15 is received, and a sleeve-shaped magnetic core 18, which serves to reduce the magnetic resistance and the formation of an air gap to a magnetic armature 19 in the magnetic circuit the electromagnet 14 is inserted into the sleeve-shaped, thin-walled, upper housing portion 12 and fixed therein. The magnet armature 19 opposite the magnetic core 18 with an axial gap spacing is displaceably guided in the valve housing 11 and fixedly connected to a valve needle 20. For placing the electromagnet 14 on the upper Housing portion 12 of the pot bottom 172 of the magnet pot 17 is provided with a central bottom opening 173, so that the pot bottom 172 rests against the upper housing portion 12. The magnetic circuit of the electromagnet 14 is closed by a yoke 22 which rests at least in sections on the one hand on the inner surface of the pot wall 171 and on the other hand on the upper housing portion 12. In the magnetic core 18, a valve closing spring 37 is arranged, which is supported on the valve needle 20 and a pressed-in in the magnetic core 18 adjusting sleeve 38 and presses the valve needle 20 with its valve head on the valve seat in the valve seat carrier. The magnitude of the spring force of the valve closing spring 37 is determined by the Einpresstiefe the adjusting sleeve 28.

The bobbin 15 has a hollow-cylindrical carrier body 151 and two carrier flanges 152 delimiting the carrier body 151 at the end. The magnetic coil 16 is wound onto the carrier body 151 and fixed axially by the carrier flanges 152. On both carrier flanges 152, an axially projecting labyrinth 23 is formed in each case, which consists of a plurality of concentric webs 231. At the upper support flange 152 an insulating dome 24 is still formed, which encloses two electrical connection pins 25 for the magnetic coil 16. The pins 25 are led out of this at the free end of the insulating dome 24 and formed for contacting with contact sockets 26 of a connector plug 27. At the lower support flange 152, a spacer 28 is formed, which produces a defined axial distance of the bobbin 15 to the pot bottom 172 of the magnet pot 17. The labyrinths 23, the spacer 28 and the Isolierdom 24 are formed in the manufacturing process of the existing plastic coil carrier 15 equal with.

The bobbin 15 with magnetic coil 16 is arranged in the magnet pot 17 so that the remote from the magnetic coil 16 inner wall of the support body 151 on the sleeve-shaped, upper housing portion 12 is directly pushed. The bobbin 15 is at a radial distance from the pot wall 171 and with a distance from the spacer 28 predetermined axial distance from the pot bottom 172 in the magnet pot 17 a. The space between coil support 15 with wound magnetic coil 16 and the magnet pot 17 is injected with plastic, which also covers the upper support flange 152, so that the coil support 15 is enclosed by a up to the sleeve-shaped upper housing portion 12 reaching plastic jacket 29. When injecting the bobbin 15 on the one hand, the yoke 22 is integrated into the plastic jacket 29 and on the other hand, a plug 30 integrally formed on the plastic jacket 29 with. The plug 30 has a freely tapered at its free end recess 31 and serves for pushing the connector 27. The recess 31 is formed so that the Isolierdom 24 something in the recess 31 protrudes beyond the bottom outward When sliding the connector 27 on the plug 30, the contact bushes 26 of the connector plug 27 push out of the Isolierdom 24th projecting pins 25 on. During plastic injection, the plastic shrinks onto the labyrinths 23 on the carrier flanges 152 and seals the magnetic coil 16 with respect to the sleeve-shaped, upper housing section 12. The salt mist occurring under certain environmental conditions, which penetrate between the sleeve-shaped, upper Gehäuseabschhitt 12 and the coil carrier 15, thereby can not reach the magnetic coil 16 and damage it in the long term. The fact that the insulating dome 24 projects substantially beyond the bottom of the recess 31 in the plug 30 also prevents the salt mist from reaching the magnetic coil 16 via the magnetic coil connection.

As in Fig. 2 is shown, the Isolierdom 24 may alternatively end in front of the recess 31 of the plug 30. In this case, the insulating dome 24 is provided with a circumferential labyrinth 32. In the embodiment of Fig. 2 the labyrinth 32 is formed by three annular webs 321, which protrude radially from the insulating dome 24 at an axial distance from one another.

The electromagnet 14 described above with the magnet pot 17, the coil support 15 which is embedded in the magnet cup 17 by means of the plastic jacket 29 and carries the magnet coil 16, the yoke 22 integrated in the plastic jacket 29 and the plug 30 integrally formed on the plastic jacket 29 forms a prefabricated assembly unit. which is completely pushed onto the sleeve-shaped, upper housing portion 12 of the injection valve during assembly of the injection valve. Subsequently, a plastic extrusion 33 is applied to the plastic jacket 29 on the upper side facing away from the bottom of the pot 172, which encloses the connecting piece 34.

In Fig. 3 is another embodiment of the injection valve according to Fig. 1 used electromagnet 14 shown. This embodiment differs from that Fig. 1 Electromagnet 14 described by the fact that the coil carrier 15 is fully enclosed with magnetic coil 16 of a one-piece plastic jacket 39, so is virtually encapsulated in the plastic. In this case, the labyrinths on the carrier flanges 152 and on the labyrinth on the insulating dome 24 can be dispensed with. At the coil carrier 15 inserted at a radial distance from the pot wall 171 of the magnetic pot 17 is a formed on the bottom of the pot 172 abstützender first spacer 40 and a radial distance from the sleeve-shaped, upper housing portion 12 and the inner wall of the plastic sheath 39 herstellender, second spacer 41 is formed. To encase the bobbin 15 with wound magnetic coil 16, the space between the bobbin 15 and the magnet pot 17 on the one hand and the bobbin 15 and the upper housing portion 12 on the other hand completely sprayed with plastic, which also covers the remote from the bottom 172 pot flange 152 and the to the Coil holder 15 molded Isolierdom 24 encloses. When spraying the plastic sheath 39, of course, a demolding core replacing the upper housing section 12 is inserted into the magnetic pot 17.

In order to reduce the dimensions of the electromagnet 14 in the radial and axial directions, without reducing the volume of the magnetic coil 16 and thus the power of the electromagnet 14, is in the embodiment of the electromagnet 14 according to Fig. 4 the bobbin 15 is arranged in the magnetic pot 17 so that the remote from the magnetic coil 16 inner wall of the support body 151 on the sleeve-shaped upper housing portion 12 can be pushed. The bobbin 15 is in turn received at a radial distance from the pot wall 171 in the magnet pot 17 and lies with its lower support flange 152 on the pot bottom 172. In the remaining space between the bobbin 15 with wound magnetic coil 16 and the magnet pot 17 is in turn injected plastic that covers the remote from the bottom 172 pot flange 152 up to the housing portion 12 and a plastic jacket 42 forms around the bobbin 15. The plastic is matched to the material of the bobbin 15 and the spray parameters of the plastic, such as temperature and injection pressure, chosen so that the plastic and the material of the bobbin 15 at the contact surfaces 43, 44 intimately connect to each other, so that in turn Magnet coil 16 is sealed relative to the interface between the carrier body 151 and sleeve-shaped housing portion 12.

In an alternative embodiment, the prefabricated mounting unit is carried out without magnetic pot 17 and this then from coil element 15, with magnetic coil 16, plastic jacket 29, 39 and 42 with integrated yoke 22 and molded connector 30 existing assembly unit in the assembly line of the injector inserted into the magnet pot 17 , Furthermore, even the yoke 22 can be removed from the mounting unit and placed as a separate component in the assembly of the injector to the pot opening of the mounting cup 17.

Claims (9)

1. Injection valve, in particular for fuel injection systems of internal combustion engines in motor vehicles, having a valve housing (11) which has a sleeve-shaped housing section (12) and having an electromagnet (14), which electromagnet is arranged on the housing section (12) and which electromagnet has a coil carrier (15) with a carrier body (151) and with carrier flanges (152) which delimit said coil carrier at the end sides and which electromagnet has a magnet coil (16) wound on the carrier body (151) and which
   electromagnet has a magnet pot (17), which magnet pot receives the coil carrier (15) and has a pot wall (171) and has a pot base (172) which surrounds the housing section (12) by way of a base opening (173),
   wherein the coil carrier (15) with magnet coil (16) wound thereon is completely surrounded on all sides by a unipartite plastics casing (39), such that said coil carrier is in effect completely encapsulated in the plastic,
   characterized
   in that pot wall (171) and pot base (172) of the magnet pot (17) are in one piece, and
   the coil carrier (15) has at least one spacer (40) which is supported on the pot base (172) and which produces an axial spacing to the pot base (172), and the coil carrier has at least one spacer (41) which produces a radial spacing to the housing section (12), and in that the free space between coil carrier (15) with magnet coil (16) wound thereon and magnet pot (17), at one side, and between coil carrier (15) and magnet coil (16) wound thereon and housing section (12), at the other side, is completely filled, by injection moulding, with a plastic which forms the plastics casing (39), which plastic furthermore lines the carrier flange (152), averted from the pot base (172), of the coil carrier (15).
2. Injection valve, in particular for fuel injection systems of internal combustion engines in motor vehicles, having a valve housing (11) which has a sleeve-shaped housing section (12) and having an electromagnet (14), which electromagnet is arranged on the housing section (12) and which electromagnet has a coil carrier (15) with a carrier body (151) and with carrier flanges (152) which delimit said coil carrier at the end sides and which electromagnet has a magnet coil (16) wound on the carrier body (151) and which electromagnet has a magnet pot (17), which magnet pot receives the coil carrier (15) and has a pot wall (171) and has a pot base (172) which surrounds the housing section (12) by way of a base opening (173), characterized
   in that the coil carrier (15) is arranged in the magnet pot (17) such that the inner wall, averted from the magnet coil (16), of the carrier body (151) can be pushed onto the housing section (12), in that in each case one axially protruding labyrinth (23) is integrally formed on the outside on the carrier flanges (152), and in that the coil carrier (15) with magnet coil (16) wound thereon is lined with a unipartite plastics casing (29) which covers the two carrier flanges (152) and the casing surface, facing toward the pot wall (171) of the magnet pot (17), of magnet coil (16) and carrier flanges (152).
3. Injection valve according to Claim 2, characterized in that the coil carrier (15), which lies in the magnet pot (17) with a radial spacing to the pot wall (171), has at least one spacer (28) which is supported on the pot base (172), and in that the free space between coil carrier (15) with magnet coil (16) wound thereon and the magnet pot (17) is filled, by injection moulding, with a plastic which forms the plastics casing (29), which plastic furthermore lines the carrier flange (152) averted from the pot base (172).
4. Injection valve according to one of Claims 1 - 3, characterized in that an insulating dome (24) which surrounds at least one electrical terminal pin (25) for the magnet coil (16) is integrally formed on the carrier flange (152) averted from the pot base (172), which insulating dome is integrated in the plastics casing (39; 29) which encloses the coil carrier (15) with magnet coil (16), and in that a connector socket (30) which has a central recess (31) is integrally formed on the plastics casing (39; 29), into which connector socket the at least one terminal pin (25) projects for the purposes of contacting by way of a contact jack (26) of a connecting plug (27) that can be pushed onto the connector socket (30).
5. Injection valve according to Claim 4, characterized in that the insulating dome (24) is designed to project into the recess (31) so as to protrude beyond the base thereof.
6. Injection valve according to Claim 4, characterized in that the insulating dome (24) ends before the recess (31) in the connector socket (30) and bears, on its circumference, a radially protruding labyrinth (32) into which the plastic of the plastics casing (29) engages.
7. Injection valve according to one of Claims 1 to 6, characterized in that a yoke (22) which, at least in sections, connectable the pot wall (171) to the housing section (12) and which is composed of magnetically conductive material is integrated in the plastics casing (29) so as to be axially spaced apart from the carrier flange (152) averted from the pot base (172).
8. Injection valve according to Claim 7, characterized in that the magnet pot (17), the coil carrier (15) which is embedded in the magnet pot (17) by way of the plastics casing (29) and which bears the magnet coil (16), the yoke (22) which is integrated in the plastics casing (29) and the connector socket (30) which is integrally formed on the plastics casing (29) form a prefabricated assembly unit.
9. Injection valve according to Claim 7, characterized in that the plastics casing (29; 39; 42) with embedded coil carrier (15) which bears the magnet coil (16) and with integrally formed connector socket (30) and preferably with integrated yoke (22) form a prefabricated assembly unit.

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