EP2299101A1 - Magnetic valve with directly contacted control unit - Google Patents

Abstract

The solenoid valve has a housing (32,51) with a magnetic core (33) and an embedded coil (35). The housing is provided with two holes (56), where each hole contains an insulating sleeve (49). The access holes are formed in the housing to allow access to the contact surfaces (48) at the contact pins (41).

Description

State of the art:

The invention relates to a solenoid valve, in particular the control unit of a solenoid valve for a fuel injector of a high-pressure injection system. Out DE 196 50 865 A1 a solenoid valve for controlling a fuel injector is known. The solenoid valve comprises a housing, which consists of a magnetic guide sleeve, a discharge nozzle and an injector cap. In this case is a magnet pot, in which a magnetic coil is accommodated. When energized, this magnetic coil generates a magnetic field which pulls a magnet armature up against a spring force and thus actuates the solenoid valve. For electrical control of the solenoid valve lead of contact pins of the solenoid two additional contacts, which are connected to the contact pins of the solenoid, through the injector cap to the outside, the injector cap serves as electrical insulation of the contacts and as a protective cap against mechanical deformation of the contact pins.

In DE 198 32 826 A1 discloses a solenoid valve for controlling a fuel injector, in particular a two- or multi-part solution for the electrical connection with plug or weld connection between the contact pin of the solenoid and the contacting element of the injector in the injector.

In the known from the prior art solenoid valves are for the realization of short drive times and high, reproducible switching accuracy in the assembly and testing of the valve numerous complex operations for fine adjustment, such as the Magnetankerhubs or the spring preload, necessary. The injector cap is manufactured as one of the last operations after the control unit is largely completely assembled, as injection molded cap made of non-conductive polymer material. Due to the unsolvable design of the component network of the control unit, the final tests of the fuel injector can be performed only after this operation, so that in a negative test result, the entire control unit must be disposed of as broke, which leads to considerable costs even at low error rates.

Advantages of the invention:

The control valve according to the invention consists of previously known technical solutions of fewer items, making it cheaper and easier to manufacture. The areas of the fuel return and the electrical contacting of the control valve are designed such that the control valve can be assembled in less assembly steps. The production-related reject rate and the associated error costs decrease due to simpler and more stable controlled production steps. The robustness of the valve against mechanical damage is increased. This is u.a. achieved in that the control unit of the solenoid valve consists of a preferably two-part housing in which a magnetic core is arranged with a recessed magnetic coil, wherein two deep-hole-shaped recesses are formed in the housing. At least one insulating sleeve is arranged in each of these recesses, which surrounds contact pins for driving the magnetic coil, wherein access holes are formed in the housing, which allow access to contact surfaces of the contact pins. The contact pins do not protrude beyond the outer contour of the housing in order to avoid damage to the contact pins.

A first embodiment of the solenoid valve is characterized in that the electrical contacting of the control unit of the solenoid valve via a contact ring consisting of preferably two contact pins, at least one lying on the contact pins insulation sleeve and each contact pin a sealing element, wherein the contact ring on the contact pins of the magnetic coil is either plugged or connected by a cohesive, non-positive or positive connection, for example by welding, soldering or a crimp, firmly connected to the contact pins of the solenoid.

An advantage of this configuration is that the contact ring can be prefabricated or preassembled as an assembly and thus reduces the assembly effort of the solenoid valve.

An advantageous development of this solenoid valve is that the insulating sleeve of the contact ring at an end remote from the magnetic core of the contact pins has an insulation cap which is connected via at least one web so with the rest of the insulating sleeve, that the contact pin is exposed in the region of the webs, so that the contact pins are not electrically isolated only in this area. For welding of the contact ring, esp. The contact pins of the contact ring with the contact pins of the solenoid, even at the magnetic core end facing the contact pins for the electrical connection of the contact pin to Kontaktpin necessary area on the contact pin be free of insulation material. In this case, the material of the insulating sleeve is preferably made of an electrically non-conductive plastic.

In a further embodiment, the unit of contact pin and contact pin of the magnetic coil can consist of only one continuous contact pin. The insulation sleeve is applied to the contact pins of the magnetic coil. An advantage of this embodiment is that the connection between the contact pins of the contact ring and the contact pins of the magnetic coil can be omitted and thus the assembly cost is reduced.

In a further embodiment, the insulation cap is made of a nonconductive polymer material, preferably an elastomer, wherein the insulation cap at the outer diameter of the insulation of the contact pins have an allowance relative to the inner diameter of the bores in the housing, preferably with respect to the inner diameter of the bores of the outlet part forming a housing part, so that the insulation sleeve the area inside the housing against leakage of fuel or liquid penetration seals. An advantage of this embodiment is that it can account for the additional sealing element on the insulating sleeve of the contact pin or on the contact pin itself.

In a further embodiment, a base plate is formed on the magnetic core side facing the contact ring, which can accommodate a stroke stop for the armature, such as a support plate and / or a throttle for the injector return.

In an advantageous development of this base plate is formed by a suitable shape and choice of material such that it can be clamped similar to a plate spring between the magnetic core and the stroke stop for the armature, so that the magnetic core pressed into the housing part forming a magnetic sleeve and on the other side of the Stroke stop is pressed against the another housing part forming outlet nozzle. This development is particularly advantageous because the magnetic core and the stroke stop can be securely fixed in the housing without further components.

In a further embodiment, an increase is pronounced on the contact ring and a corresponding depression in the opposite end face of the downcomer, so that twisting of the contact ring with respect to the downcomer is reliably avoided. Alternatively, an increase in the discharge nozzle and a corresponding corresponding recess in the contact ring may be formed.

An advantage of this design is increased security against rotation of the contact ring, esp. In the assembly processes before the contact ring is connected to the solenoid.

In a further embodiment, a chamber is formed at the bottom of the access hole in the discharge nozzle or in the region of the intersections between the access holes and the holes in the discharge nozzle. An advantage of this embodiment is that sharp edges are avoided by this chamber at which electrical connection cables could be damaged during assembly or during operation. It is also advantageous that in this chamber a corresponding connector can engage such that Here is a positive and permanently secure connection between the plug and contact surface of the pins is guaranteed.

In a further embodiment, the discharge nozzle, which forms part of the housing, is made of plastic or as a MIM (Metal Injected Molding) component. It is advantageous here that the production costs for an injection molded part are significantly lower for large quantities than for a corresponding rotary part with a similar geometry. In an advantageous development of the outlet pipe is designed as an injection molded part with inserted welding ring, which can be permanently connected to the outlet sleeve forming a further magnetic sleeve, so that no liquid leak from the housing or from the outside into the via the connection point between drain pipe and magnetic sleeve Housing can penetrate.

In a further embodiment, a central return bore is formed in the housing, preferably in the outlet part forming a housing part, in which a return line can be fixed via a special geometry. An advantage of this embodiment is that while a compatibility of the return to existing injectors can be achieved.

Another embodiment of the control valve is characterized in that the contact ring is plugged with a detachable plug connection to the contact pins of the magnetic coil. This solution also has the advantage that the valve can be tested for function before the two housing parts are welded together. This solution has the advantage that when the setpoints are not reached in a functional test, the control unit can be dismantled and readjusted without having to write off the complete control unit as a reject part.

Drawings:

• Fig. 1 shows a longitudinal section through a fuel injector with a solenoid valve according to the prior art
• Fig. 2 shows enlarged the valve piece of a known from the prior art fuel injector in longitudinal section
• Fig. 3a shows a longitudinal section through a control unit of a solenoid valve according to the prior art
• Fig. 3b shows a further, rotated 90 ° longitudinal section through a control unit of a solenoid valve according to the prior art
• Fig. 4 shows a longitudinal section through the control unit according to the invention of the solenoid valve
• Fig. 5a illustrates in detail the contact ring of the solenoid valve according to the invention is in longitudinal section
• Fig. 5b shows the contact ring in perspective view.
• Fig. 6a represents in detail the outlet nozzle of the solenoid valve according to the invention in longitudinal section.
• Fig. 6b shows the drain pipe in perspective view

Description of the embodiments:

In Fig. 1 a fuel injector 10 known from the prior art is shown in sectional view.

The fuel injector 10 comprises an injection nozzle 12, an injector body 11, on which a high pressure port 15 is formed laterally, and a solenoid valve 18, which consists of a valve piece 20, a magnet armature 28 and a control unit 30.

In the injector 11, a valve piston 14 and a valve member 20 are arranged coaxially in a bore. Between the valve member 20 and the injector body 11 is an annular space 21, which with the high pressure port 15 in direct Connection stands. The injection nozzle 12 consists of a nozzle body 16 and a nozzle needle 13, wherein at least one injection hole 17 is formed on the nozzle body 16 in the tip region, can be injected through the fuel into a combustion chamber of an internal combustion engine. Between the valve member 20 and the end face of the valve piston 14, a control chamber 23 is formed, which is connected via an inlet throttle 22 with the annular space 21 of the fuel injector 10. At the magnet armature 28 facing end face of the valve member 20 is a valve seat 25th

As in Fig. 2 shown in detail, the valve seat 25 and the control chamber 22 are connected by an outlet throttle 24, wherein a valve ball 26 so cooperates with the valve seat 25, that the outlet throttle 24 is closed by the valve ball 26 in the case of a non-actuated control unit 30. In this case, the valve ball 26 is fixed by a ball guide 27 on the armature 28 in its position.

The in the Fig. 3a and 3b shown control unit 30, which is bolted to the injector body 11 via a magnetic clamping nut 31, corresponds to the prior art and comprises a magnetic core 33 with a recessed magnetic coil 35, a magnetic sleeve 32, a discharge nozzle 51 and is driven via an electrical connection 50, which from in each case two flat plugs 46 and two contact pins 41, which are connected to each other via a respective plug connection element 62, wherein the contact pins 41 constitute a part of the magnetic coil 35. When the control unit 30 is energized, the magnetic coil 35 in the magnetic core 33 generates a magnetic force which corresponds to the magnetic field in the magnetic core 33 Fig. 1 shown magnet armature 28 with a arranged on the underside of the armature 28 ball guide 27 against the force of the valve spring 29 attracts. By a difference between the pressure in the return bore 52 and the pressure in the control chamber 23, the valve ball 26 is pressed out of the valve seat 25. By now via the outlet throttle 24 flowing fuel, the pressure in the control chamber 23 is reduced, so that moves in a known manner, the association of valve piston 14 and nozzle needle 13 and the nozzle needle 13 lifts, whereby the fuel through the injection holes 17 in the nozzle body 16 of the injection nozzle 12 can flow into the combustion chamber of the internal combustion engine.

For fixing the magnetic core 33 in the magnetic sleeve 32, the control unit 30 has a in the Fig. 3a and Fig. 3b shown plate spring 37, which braces the magnetic core 33 and a holding plate 39 against each other. The valve spring 29 is guided at one end by the anchor pin 45, which is formed at the upper end of the armature 28, and at the other end of the holding plate 39. The magnet armature 28 is guided through the guide bore 34 in the magnetic core 33.

The magnetic coil 35 in the magnetic core 33 comprises two contact pins 41, which together with a fixed at the end of the contact pins 41 plug connection elements 62 and the tabs 46 form the electrical connection 50. The contact pins 41 are guided in the holding plate 39 by a respective support plate 38. Via sealing elements 44, which are located in the holding plate 39 above the support plate 38, the fuel-carrying region is sealed in the control unit 30 and thus prevents a fuel leak along the electrical connection 50th

The electrical connection 50 is protected by a non-conductive injector cap 63, which extends from the magnetic sleeve 32 to the drain port 51, against mechanical damage and short to ground with metallic injector components.

In Fig. 4 an embodiment of the control unit 30 of the solenoid valve 18 according to the invention is shown. The control unit 30 comprises a housing 32,51, here consisting of a magnetic sleeve 32 and a discharge nozzle 51. However, this housing 32,51 can also be made in one piece.

In this housing 32,51 of the magnetic core 33 is arranged, which is supported on a shoulder 64 of the magnetic sleeve 32. In this magnetic core 33, a magnetic coil 35 is received with contact pins 41. These contact pins 41 are each encased by an insulating sleeve 49, wherein the insulation sleeves 49 are located in two bores 56 formed in the outlet nozzle 51.

At the end of the insulating sleeve 49 facing away from the magnet coil 35, an insulation cap 42 is formed on each contact pin 41, which serves to electrically insulate the contact pins 41 against the metallic outlet connection 51. This insulation cap 42 is followed by a region where the contact pin 41 is at least partially freed at the electrically conductive surface and thus contact surfaces 48 on the contact pins 41 allow electrical contacting of the magnetic coil 35. In this case, the insulating sleeve 49 can also be made in several parts, wherein the insulation cap 42 is then not connected to the insulating sheath of the remaining insulating sleeve 49 and the area of the contact surface 48 is not protected by a web 43 on the contact pin 41. In the region of the bores 56 in the outlet connection 51 between the access bores 53 and the magnetic core 33, a sealing element 44 is arranged on the outer surface of the insulation sleeve 49 on each jacket of the contact pins 41, which prevents fuel leakage along the path of the electrical connection 50. Alternatively, the insulating sleeve 49 itself can be made of a hydraulically sealing material and be pressed into the holes 56, that a comparable sealing effect is formed.

Fig. 5a showed a longitudinal section through a contact ring 40, which is an assembly consisting of contact pins 41, insulating sleeve 49 with molded webs 43, the insulation cap 32 and sealing elements 44.

If such a contact ring 40 is used, it is different from the representation in FIG Fig. 4 In addition, a short contact pin 36 is present on the magnet coil 35, wherein the contact pins 36 of the magnetic coil 35 are fixedly connected to the contact pins 41 of the contact ring. Alternatively, the connection of contact pin 36 and contact pin 41 can be carried out as a releasable plug connection, wherein one of the contact elements 36,41 are designed as a socket into which the other contact element 36,41 can be inserted.

In an in Fig. 4 and Fig. 5a illustrated advantageous development of the contact ring 40, a base plate 57 is formed, which is located on the magnetic core 33 facing the front side of the contact ring 40. About this base plate 57 of the contact ring 40 between the magnetic core 33 and drain pipe 51 is braced such that the contact ring 40 presses the magnet pot 33 in the magnet sleeve 32. In addition, the base plate 57 has at its inner diameter an Anformung 65 for receiving a support plate 38. In this case, the base plate 57 formed such that the Anformung 65 for receiving the support plate 38 includes two lateral edges 66, which are suitable for guiding a valve spring 29.

The in Fig. 6a and Fig. 6b illustrated drain port 51 represents a housing part of the control unit 30 of the solenoid valve 18 and has a central return bore 52 for connection to a return line, not shown. At the end face 58 on the underside of the downcomer 51, two bores 56 are formed, which are suitable for receiving the contact ring 40 or the insulating sleeves 49. The contacting of the contact surfaces 48 on the contact pins 41 via the access holes 53 in the housing 32,51, these access holes 53 are preferably formed in the drain port 51. The access holes 53 meet in an intersection on the bore 56 in the drain port 51, wherein the decision is ideally at the height of the contact surface 48 on the contact pin 41.

In order to facilitate the electrical contacting of the control valve, a chamber 61 is formed in the region of the intersection of the bores 56 and the access holes 53 in the drain port 51, in which an external contact plug can engage. Such a chamber 61 is not necessarily required for the control valve and may also be omitted.

On the outer region of the end face 58 of the drain neck 51, contact surfaces 59 are formed, via which the drain neck can be fixed to a further housing part 32.

In an embodiment of the drain neck 51 made of a polymer material, a welding ring 60 can be injected into the contact surface 59 in order to improve the connectability to the further housing part 32. In this case, each method is suitable for the connection of the outlet nozzle with the further housing part 32, which results in a result in a permanently hydraulically sealed connection of the two housing parts 32,51.

Claims (14)

Solenoid valve for controlling a fuel injector (10) with a housing (32, 51) in which a magnetic core (33) with a recessed magnet coil (35) is arranged, wherein two bores (56) are formed in the housing (32, 51), in which in each case an insulating sleeve (49) is arranged, which contact pins (41) for driving the magnetic coil (35) enclose, characterized in that in the housing (32,51) access holes (53) are formed which an access to a contact surfaces ( 48) on the contact pins (41). Solenoid valve according to claim 1, characterized in that the electrical contacting of the control unit (30) of a solenoid valve (18) via a contact ring (40), which consists of two contact pins (41) and at least one insulating sleeve (49), wherein the contact pins ( 41) of the contact ring (40) with contact pins (36) of the magnetic coil (35) are firmly connected, for example by welding, soldering or a crimp connection. Solenoid valve according to Claim 2, characterized in that an insulation sleeve (49) with an insulation cap (42) and a web (43), preferably in the form of a non-conductive plastic coating, is formed on the contact ring (40), so that the contact pin (41) in the region of the recesses of the webs (43) and in the contact region between the contact pin (41) of the contact ring (40) with the contact pin (36) of the magnetic coil (35) is exposed. Solenoid valve according to claim 1, characterized in that the contact pin (41) is fixed directly in the magnetic coil (35) and an insulating sleeve (49) on which an insulation cap (42), a web (43) and a further insulating surfaces are formed, is arranged such that the contact pin (41) in the region of the recesses of the webs (43) is exposed. Solenoid valve according to claim 1 to 4, characterized in that the insulation cap (49) made of a non-conductive polymer material, preferably an elastomer, compared to the diameter of the bores (56) in the outlet nozzle (51), which is a part of the housing (32,51 ), has a suitable allowance and is pressed into the bores (56) in such a way that no fuel can escape from the housing (32, 51) via the bores (56) and the access bores (53). Solenoid valve according to Claim 2, 3 or 5, characterized in that a base plate (57) is formed on the side of the contact ring (40) facing the magnetic core (33), which provides a stroke stop for the magnet armature (28), for example in the form of a support plate (38). Solenoid valve according to claim 6, characterized in that the base plate (57) of the contact ring (40) is formed by suitable shape and choice of material such that it, like a disc spring, between the magnetic core (33) and the support plate (38) is braced so in that it presses the magnetic core (33) into the magnetic sleeve (32), which forms part of the housing (32, 51), and the support plate (38) against the discharge nozzle (51) forming part of the housing. Solenoid valve according to claim 2,3,5,6 or 7, characterized in that on the contact ring (40) and the end face (58) of the discharge nozzle (51) at least one opposite increase of the one component (40,51) and at least one Recess of the other component (40,51) are formed so that a rotation of the contact ring (40) relative to the discharge nozzle (51) is prevented by positive engagement. Solenoid valve according to claim 1 to 8, characterized in that at the bottom of the access bores (53) in the outlet port (51) or in the region of the intersection between the access bores (53) and the bores (56) in the outlet port (51) has a chamber (61). is formed, which gives access to the contact surfaces (48) of the contact pins (41) facilitates or in which a connector can be positively fixed. Solenoid valve according to claim 1 to 9, characterized in that the discharge nozzle (51) is designed as a plastic injection-molded component with a on the contact surface (59) of the discharge nozzle (51) inserted welding ring (60) Solenoid valve according to claim 1 to 10, characterized in that the discharge nozzle (51) is connected to the magnet sleeve (32) such that via the connecting point (54) between the contact surface (59) of the discharge nozzle (51) and the magnet sleeve (32) no Liquid from the housing (32,51) to the outside or from the outside into the housing (32,51) can penetrate. Solenoid valve according to claim 11, characterized in that the connection point (54) is designed as a weld, solder joint or splice. Solenoid valve according to claim 1 to 12, characterized in that the outlet nozzle (51), which is a part of the housing (32,51), has a central return bore (52) for receiving a return line (55). Fuel injector (10), characterized in that the fuel injector (10) includes a solenoid valve with a control unit (30) according to any one of claims 1-13.

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