WO2008104424A1 - Magnetic head for solenoid valve - Google Patents

Abstract

The invention relates to a fuel injector comprising a solenoid valve. The solenoid valve comprises a magnetic head (10) and a sleeve body (16), in which a solenoid core (26) and a solenoid coil (28) are accommodated. The solenoid coil (28) is electrically connected via connector pins (42). A rotatably disposed cover cap (14) is placed on the sleeve body (16), wherein heads for the connector pins (42) are formed in the contacts (44). The cover cap (14) is preferably clipped onto the magnetic head.

Description

 description

title

Magnetic head for solenoid valve

State of the art

DE 196 501 586 A1 relates to a solenoid valve for controlling the fuel pressure in a control chamber in an injection valve such as a common rail injection system. About the fuel pressure in the control chamber, a stroke movement of a valve piston is controlled, with which an injection port of the injection valve is opened or closed. The solenoid valve comprises an electromagnet, a movable armature and a valve member which is moved with the armature and acted upon by a valve closing spring in the closing direction and which cooperates with the valve seat of the magnet valve and thus controls the fuel outflow from a control chamber.

In known solenoid valves occurring in operation bouncing of the armature and / or the valve member has a very disadvantageous. By an oscillation of the impinging on the valve seat anchor plate, the anchor plate takes an undefined position. Thus, in subsequent injections with the same control to different opening times of the solenoid valve and thus to a dispersion of the injection start and the injection quantity. According to DE 196 50 586 A1 and DE 197 98 104 Al known solution of the armature of the solenoid valve is designed as a two-part armature so as to reduce the moving mass of the unit armature valve member and thus the bouncing kinetic energy.

In today's high-pressure injection systems, such as solenoid valves used for high-pressure accumulator injection systems (common rail), a magnetic head is fixed on the injector body in such a way that the magnet is supported directly or indirectly on a shoulder in the injector body. If appropriate, a housing which encloses the magnet in a form-fitting manner can also be pressed against this shoulder. The fixation is usually carried out with a magnetic clamping nut, which comprises the magnet or a sleeve surrounding the magnet from above and is screwed onto an external thread located on the injector body. The valve piece on which the valve seat of the solenoid valve is formed, by means of a second Schraubverbandes inside the injector body pressed against a second shoulder. During operation, the valve piece is pressurized from below with system pressure, ie the pressure level prevailing in the high-pressure reservoir (common rail). As a result, the valve member is displaced within its Schraubverbandes by a few microns up, causing the axial position of the valve seat relative to the injector depending on the system pressure, ie the pressure in the high-pressure accumulator (common rail) changes.

If the upper stop for the solenoid valve is also within the screw connection for fixing the valve piece, then both the valve seat and the upper stroke stop are displaced upward under system pressure and a system pressure-dependent reduction of the previously carefully set residual air gap occurs. In order to maintain a minimum residual air gap even at maximum system pressure, this pressure-dependent reduction of the residual air gap is maintained when it is adjusted. However, this provision in turn means that the actually available magnetic force can not be fully utilized. If the upper limit stop for the magnetic valve is within the first screwed connection for the magnetic head, the valve lift is reduced as a result of the displacement of the valve seat, depending on the system pressure. This is particularly disadvantageous because the displacement of the valve seat during the valve lift must be maintained and thus the desired for the stability of the switching behavior, the lowest possible valve lift at medium and small pressures is no longer present.

The construction of a solenoid valve assembly, ie, the solenoid valve in the fuel injector, is similar in most embodiments. A twisted magnet sleeve accommodates a magnetic coil, the magnetic core and a drain neck, which is generally produced as a rotated component. The hydraulic seal on the inside is done by means of one or more O-rings. After assembling the parts, the assembly is crimped and then carried the assembly of the connector lugs for contacting the magnetic coil and a welding of the pins. Finally, an encapsulation of the resulting preassembled module for shaping the plug geometry and the outer geometry of the magnetic head. To cover a plurality of plug variants and to provide different outlet angles of plugs, a plurality of Umspritzungswerkzeugen that allow different embodiments of this final plastic injection, held up. In general, a radial alignment of the connector lugs during assembly of the magnetic head by means of a device before or during the screwing of a magnetic clamping nut takes place. The present design of the magnet assembly, however, is associated with relatively high manufacturing costs. By crimping and the plastic extrusion disassembly of a faulty magnet assembly is no longer possible, so this committee represents. In some embodiments of fuel injectors, the crimping process is as To classify very critically, since this can have very negative effects on the lift drift of the armature.

Presentation of the invention

According to the invention, a magnetic head for a solenoid valve assembly is proposed, which is modular and has a clip-on plug contact. The radial alignment of the plug outlet can be adjusted infinitely variable. The male clip can be selected to accommodate different connector types and different angular outputs of the male contacts. Due to the modular design of the magnetic head with a clip-on connector, the process of flanging, the execution of a cohesive connection by welding the connector pins and the encapsulation of the magnetic head can be completely eliminated. The elimination of this work or assembly steps, a significant cost reduction can be achieved, the functionality of such a trained magnetic head of a solenoid valve assembly is maintained. In addition, can be achieved by the erfmdungsgmäß proposed solution that eliminates the magnetic clamping nut. In one embodiment of the idea underlying the invention, the magnetic head housing is manufactured as a deep-drawn, hot or cold formed cup-shaped steel component, which includes a return pipe in its design. The pot-shaped component comprises an external thread, a disassembly favoring hexagon and two openings for the passage of the connector pins and finally a screwed-in groove for engaging retaining clips. Furthermore, a return pipe is formed on the pot-shaped component. During assembly, the magnetic coil is first inserted into the magnetic core and held in it by means of two molded plastic detents. An extended Drahtumspritzung ensures the centering or isolation of the pins to the housing. The support of the core is possible either by using a spacer sleeve, by gluing or by using a snap ring. A rubber seal or a rubber plate or the like insulates the magnet core, or the magnet coil, to the injector body and takes over the sealing of the plug pins to the outside.

The clip-on connector clip is preferably produced as an injection-molded part and comprises the inserted connector lugs. The connector lugs have on one side the plug geometry depending on the application purpose and on the other side the connector lugs are designed as resilient elements. As a result, when resiliently clipping the connector clips, these resilient elements can latch onto the connector pins and form a permanent connection with them, in which a self-bias is always ensured. -A-

During assembly, the screwing or mounting of the magnetic head takes place on the already pre-assembled and equipped injector body. The magnetic head can be received on a screw device, for example, by means of the hexagon formed on it. After the connection between the head and the injector body has been carried out, a high-pressure tightness test and a low-pressure tightness test can be carried out, as well as quantity measurement via a removable mounting adapter. Depending on the structural design of the support of the magnetic core in the injector, this can be completely dismantled, which can be carried out until after the wet test, so that no magnetic head assemblies are made as a committee. After the high-pressure tightness test and before labeling with a laser, the plug top can be mounted in the last assembly step to avoid rejects. To secure the electrical contact points connector pin / spring element can perform a simple current or resistance test. Alternatively, the magnetic head assembly can also be completely completed first and then undergo the wet test in this form.

Brief description of the drawings

With reference to the drawing, the invention will be described below in more detail.

It shows:

1 shows a section through the magnetic head of a valve assembly proposed according to the invention, FIG.

FIG. 2 is an external view of the sleeve body accommodating the solenoid valve assembly;

FIGS. 3.1 to 3.3 different embodiments of the fixation of the magnetic core in the sleeve body,

4 shows a contacting possibility of the magnetic coil accommodated in the magnetic core, FIG.

FIGS. 5.1 and 5.2 representations of a sealing disk arranged between cover cap and sleeve body of the magnetic head;

FIG. 6 a representation of the region within which the sealing disk is fixed between the sleeve body and the cover cap, FIG. 7 shows an enlarged view of the plug pin area,

FIG. 8 shows a plan view of the plug connection,

Figures 9.1 and 9.2 embodiments of the contact within the cap between the head of the plug pins and contact semicircles according to the representation of Figure 8 and

Figures 10.1 and 10.2 is a plan view and a side view of the cap of the magnetic head.

embodiments

The illustration according to FIG. 1 shows a section through the magnetic head of a valve assembly proposed according to the invention.

FIG. 1 shows a magnetic head 10, which is covered with a cover cap 14. The magnetic head 10 comprises the upper part of a sleeve body 16, which is constructed symmetrically to an axis 12. The sleeve body 16 has an outer side 18 and a

Inner side 20 and is formed substantially cylindrical. In the cap 14, a drain 22 is integrated, via which fuel from a magnetic head 10 having fuel injector flows back into the low-pressure side return of the fuel injection system.

There is a sealing washer 24 between the underside of the cap 14 and the top of the sleeve body 16. The sealing disc 24 has an opening aligned with the outlet 22 integrated in the cap 14, through which the controlled amount of control flows out of the fuel injector.

The sleeve body 16 encloses a magnetic core 26, in which in turn a magnetic coil 28 is embedded. The magnet coil 28 is contacted via plug pins 42 in a contact 44 within the cover cap 14. For electrical contacting of the connector pins 42 on the contact 44, the cap 14 has a plug connection 46. The radial orientation of the connector terminal 46 can be adjusted continuously to a great extent. The cap 14, which is clipped onto the upper side of the sleeve body 16 with the interposition of the sealing disk 24, can be manufactured as a selection group in order to configure different plug connections 46 and different angular positions. gurierte to realize disposals.

On the outer side 18 of the sleeve body 16 is a recess 30 made, for example, as an annular groove, in which a hook 40 of at least one articulated clip 54 mounted in a hinge 38 of the cover cap 14 is engaged. For manufacturing technology advantageously, the recess 30 may be made as a recess on the outer side 18 of the sleeve body 16.

Furthermore, located on the outer side 18 of the sleeve body 16 is a sealing seat 32 into which a sealing ring 34 produced, for example, as an O-ring can be inserted.

The outer side 18 of the sleeve body 16 also has a threaded outlet 36.

The illustration according to FIG. 1 furthermore shows that an end face of the magnetic core 26 of the magnetic head 10 is identified by reference numeral 48. An end face of the cap 14 which assigns the sealing disc 24 is identified by the reference numeral 50. Between the recess 30, for example, provided as a groove-shaped recess on the outer side 18 of the sleeve body 16 and the seal receptacle 32, a tool attachment 52 is formed on the sleeve body 16, which can be designed as a hexagon or the like, for example, like a screw head. An opening 56 in the sleeve body 16 is used to pass the connector pins 42 through the cap 14 for electrical contacting of the magnetic core 28 enclosed by the magnetic coil 28th

In the sleeve body 16 shown in Figure 1 is a deep-drawn, hot or cold formed steel component, in which the drain 22 is integrated. On the sleeve body 16 is a thread 36, as the already mentioned tool attachment 52 and the two openings 56 for the passage of the connector pins 42nd

The magnetic coil 28 is inserted into the magnetic core 26 and can be held in this, for example, via one or more molded plastic latches. The plug pins 42 are surrounded by an encapsulation, over which the plug pins 42 are isolated from the sleeve body 16 on the one hand and on the other hand are centered. The cap 14 is used as z. B. manufactured as a plastic injection molded part and includes inserted plug flags. The connector lugs have the plug geometry on one side and a spring element on the other side. As a result, when the cover 14 is clipped onto the sealing disk 24 and the covering cap 14 is fixed in position with the at least one clamping bracket 54, a permanent connection to the contacts 44 can take place be achieved. The resiliently formed elements of the contacts 44 snap into place on the connector pins 42 and form there a permanent connection, whereby always a self-bias is maintained.

FIG. 2 shows the sleeve body shown in section in FIG.

From Figure 2 shows that the recess 30 is continuous on the outer side 18 of the sleeve body 16. Below the recess 30 on the outside of the sleeve body 16 extends the tool attachment 52, below which in turn is a seal receiving 32 is located. Below the seal receptacle 32, a portion of the thread 36 is shown.

Embodiments of the fixation of the magnetic core in the sleeve body can be seen in FIGS. 3.1 to 3.3.

FIG. 3.1 shows that, according to this embodiment, the magnetic core 26 surrounding the magnetic coil 28 is fastened by an adhesive layer 60 to the inner side 20 of the sleeve body 16. The adhesive layer 60 extends between the upper end side of the magnetic core 26 and an inner side 62 of the cover of the sleeve body 16. In the magnetic core 26 are cavities in which on the one hand the magnetic coil 28 and on the other hand, the connector pins 42 are accommodated. These aligned in the assembled state with the end face 48 of the magnetic core 26th

In addition to the embodiment of a fixing of the magnetic core 26 via the adhesive layer 60 as shown in FIG. 3.1, the magnetic core 26 can also be fixed by means of a retaining ring 64 embedded in a groove 68 in the inner side 20. The retaining ring 64 has a projection 66 with respect to the inner side 20 of the sleeve body 16. About the supernatant 66, which is dependent on the depth of the groove 68 and the depth of the retaining ring 64, the magnetic core 26 can be easily clipped into the sleeve body 16. Analogous to the embodiment shown in Figure 3.1 is located in the magnetic core 26 cavities for the connector pins 42 and the magnetic core 26 enclosed magnetic coil 28. The magnetic core 26 is symmetrical to the axis 12 and the retaining ring 64 to the inside 62 on the cover of the sleeve body 16 employed.

FIG. 3.3 shows that the magnetic core 26 is supported by a support sleeve 70. The support sleeve 70 is substantially formed as an annular member and includes a first annular surface 72 and a second annular surface 74. While the second annular surface 74 for Example supported on the injector body, the first annular surface 72 of the support sleeve 70 supports the end face 48 of the magnetic core 26 from. By the support sleeve 70 and the contact between the first annular surface 72 and the end face 48 of the magnetic core 26 of this is employed on the inside 62 of the cover of the sleeve body 16.

For all the embodiments shown in FIGS. 3.1, 3.2 and 3.3, the magnet core 26 is symmetrical to the axis 12 and has cavities for receiving the magnet coil 28 and for receiving the plug pins 42 electrically contacting the magnet coil 28.

FIG. 4 shows a detailed representation of the contacting of the magnetic coil.

FIG. 4 shows that the magnet coil 28 is enclosed by the magnet core 26 and the lower end face of the magnet coil 28 is aligned with the end face 48 of the magnet core 26. The magnet coil 28 electrically contacting connector pin 42 is enclosed by an insulating sleeve 76. The insulating sleeve 76 encloses the plug pin 42 in an axial length which corresponds to the thickness of the material of the sleeve body 16 and about half the thickness of the magnetic core 26. The plug pins 42 and the insulating sleeve 76 enclosing them extend through the opening 56 in the cover of the sleeve body 16 as well as through the sealing disc 24 applied to the upper side of the sleeve body 16.

The plug pin 42 has a groove 78, so that upon contact of the connector pins 42 on the contact 44 through the cap 14, a snap closure is formed. The groove 78 on the plug pin 42 on the one hand creates a secure contact and on the other hand a holding force 80 indicated by the arrow 80, with which it can be prevented that the magnetic coil 28 enclosed by the magnetic core 26 leaves its installation position in the sleeve body 16. Moreover, due to the undercut between the magnet coil 28 and the magnet core 26, it is achieved that not only the magnet coil 28, but also the magnet core 26 in the sleeve body 16 is secured in its installed position when the connector pins 42 are electrically contacted.

Figures 5.1 and 5.2 show the sealing disc, which is arranged in the magnetic head between the cap and the sleeve body.

It can be seen from the illustration according to FIG. 5.1 that the sealing disk 24 has a central opening 82 which is aligned with the integrated outlet 22 of the covering cap 14, cf. FIG. In the material of the sealing disk 24, a number of openings 84 corresponding to the number of connector pins 42 is formed, through which the connector pins 42 are formed. CKEN.

FIG. 5.2 shows a sectional view through the sealing disk shown in FIG. 5.1 in plan view.

The sealing disk 24 is formed symmetrically to the axis 12 and forms on the one hand a seal between the cap 14 and the cover of the sleeve body 16 to the outside, on the other hand, a seal between the cap 14 and the opening 56 in the sleeve body 16 with respect to the control amount and further to a seal the passage point of the connector pins 42 through the opening 56 in the sleeve body 16. The sealing washer 24 is preferably made of a material such. B. Viton produced.

FIG. 6 shows a representation of the region within which the sealing disk is fixed between the sleeve body and the covering cap.

FIG. 6 shows that a ribbing or toothing 86 or the like is formed on the end face 50 of the cover cap 14, which is preferably produced as a plastic injection-molded component. This grips the edge region of the disc-shaped sealing disc 24 and pulls them during assembly of the cap 14 on the sealing washer 24 in the radial direction downwards, so that the sealing disc 24 conforms to the ceiling of the substantially cylindrically shaped sleeve body 16. After the tensioning of the sealing disc 24 takes place in the radial direction over the ribbing or toothing 86, the covering cap 14 is fixed by means of the clamping brackets 54 shown in FIG.

The outer side 18 of the sleeve body 16 is thus sealed in the roof region of the substantially cylindrically shaped sleeve body 16. The inside of the sleeve body 16 is indicated by reference numeral 20.

Figure 7 shows an enlarged view of the Steckerpinbereiches and its seal against the external environment.

The illustration according to FIG. 7 shows that the plug pin 42, via which the magnet coil 28 is contacted, is enclosed by the insulating sleeve 76. In the embodiment shown in FIG. 7, the insulating sleeve 76 is clamped between the magnet coil 28 and a region 88 on the end face 50 of the cap 14. On the end face 50 of the cap 14, which is preferably produced as a plastic injection molded component, there is the nose-shaped configured ring 88, which contacts the upper end side of the insulating sleeve 76 which surrounds the circumference of the plug pin 42. The insulation sleeve 76 and the enclosed by this connector pin 42 extends through the sealing washer 24, see Figures 5.1 and 5.2.

Also in the embodiment shown in FIG. 7, the plug pin 42 comprises the groove 78 with which - as shown in connection with FIG. 4 - a holding force 80, as shown in FIG. 4, is generated. About this groove 78 on the connector pin 42, the magnetic coil 28 can be secured in position within the sleeve body 16 directly and indirectly by the magnet coil 28 encompassed magnetic core 26th

FIG. 8 shows the plan view of the plug connection of the magnetic head proposed according to the invention.

FIG. 8 shows that the covering cap 14 in the region of the plug connection 46 comprises the two contacts 44 (see also illustration according to FIG. 1). From the representation according to FIG. 8, it can be seen that the two contacts 44 each have contact semicircles 94, which contact the plug pins 42. Due to the fact that the contact semicircles 94 surround the heads of the connector pins 42 over an angular range of about 180 °, it is possible to adjust the connector outlet so that it sweeps over a rotation angle of at least 170 ° 90 and thus can be set in different angular positions , The two contact semicircles 94 are interrupted in the cap 14 by a gap 92. Reference numeral 90 denotes the angle of rotation, which is approximately 170 ° in the illustration according to FIG.

FIGS. 9.1 and 9.2 show embodiments of the contacting within the covering cap between the head of the plug pin and the contact semicircles, as shown in FIG.

Figure 9.1 shows a variant of the contact semi-circle 94, in which a contact point 98 is located on the circumference of the connector pin 42. In this embodiment, the contact half circle 94 surrounds the head of the plug pin 42 and projects laterally into the groove-shaped recess 78 on the plug pin 42 with its open leg end. From the illustration according to FIG. 9.2, it is apparent that the contacting 44 shown there has at least one contact semi-circle 94. In contrast to the embodiment in FIG. 9.1, the embodiment of the contacting 44 shown in FIG. 9.2 shows a contact semicircle 94, which has a taper 96. By this taper 96 on the outer circumference of the contact half circle 94 is formed in the interior of the contact 44, ie contact semi-circle 94 an accumulation of material, which protrudes in accordance with Figure 9.2 in the groove 78 on the male pin 42. In this way, the plug pin 42 is connected in a form-fitting manner to the contact semi-circle 94. the, wherein in the groove-shaped recess 78 in the head region of the connector pin 42 at least one contact point 98 is formed.

The two embodiments of the contact arrangement 44 shown in FIGS. 9.1 and 9.2 ensure that the holding force 80 shown in connection with FIG. 4 acts on the plug pins 42 with a groove-shaped recess 78, which prevents the magnet coil 28 together with the magnetic core 26 from leaving it Installation position within the sleeve body 16 fall out.

Figures 10.1 and 10.2 show top or side views of the cap.

The illustration according to FIG. 10.1 shows that the cover cap 14 has an upper side 104. On the upper side 104, individual dome-shaped joints 38 are formed. Each of the joints 38 has a receptacle 102, are inserted into the axes of rotation 100 of the clamping bracket 54. Reference numeral 46 denotes the lateral plug connection of the cover cap 14. From the illustration according to FIG. 10.1, it can also be seen that in this embodiment, two clamping brackets 54 are provided on the clip-on cap 14 which can be connected to the sleeve body 16.

FIG. 10.2 shows that the clamping brackets 54 have the axis of rotation 100 at one end and the hook 40 already shown in FIG. 1 at the other end. The hook 40 engages in the recess 30 on the outside 18 of the sleeve body 16 in the clipped-on state one. The axis of rotation 100 in turn is inserted into the receptacle 102 of the dom-shaped joints 38 on the upper side 104 of the cover cap 14. Depending on the clamping force height and required sealing effect, can be adjusted on the elasticity of the legs of the clamp 54, the spring preload and thus the holding force can be adjusted.

Claims

claims A fuel injector comprising a solenoid valve comprising a magnetic head (10) having a sleeve body (16) in which a magnetic core (26) and a magnetic coil (28) are housed and the magnetic coil (28) via plug pins (42) electrically is contacted, characterized in that the electrical contacting of the magnetic coil (28) via a rotatably arranged cover (14), which is clipped onto the sleeve body (16). 2. Fuel injector according to claim 1, characterized in that the sleeve body (16) is a deep-drawn, hot or cold-formed metallic component. 3. Fuel injector according to claim 1, characterized in that the sleeve body (16) on its outer side (18) has a circumferential recess (30) for latching clamping brackets (40,54) and a tool attachment (52). 4. Fuel injector according to claim 1, characterized in that between a front side (50) of the cap (14) and the sleeve body (16) a sealing disc (24) is arranged. 5. Fuel injector according to claim 1, characterized in that the sealing disc (24) on its outer periphery by a on the front side (50) of the cap (14) formed toothing or ribbing (86) is biased. 6. Fuel injector according to claim 1, characterized in that the cover cap (14) has a lateral plug connection (46) which is connected to contacts (40), in which heads of the plug pins (42) for electrical contacting of the magnetic coil (28) protrude , 7. Fuel injector according to one or more of the preceding claims, characterized in that the cover cap (14) is manufactured as an injection-molded component, in particular as a plastic injection-molded component. 8. Fuel injector according to one or more of the preceding claims, characterized in that the cover cap (14) has an upper side (104) on which dome-shaped joints (38) are arranged, each having at least one receptacle (102) for at least one Have clamping bracket (54). 9. Kraftstoffϊnjektor according to claim 1, characterized in that the magnetic coil (28) surrounding the magnetic core (26) by means of an adhesive layer (60) in the sleeve body (16) via a retaining ring (60) in the sleeve body (16) or via a support sleeve ( 70) is supported in the sleeve body (16). 10. Kraftstoffϊnjektor according to one or more of the preceding claims, characterized in that the plug pins (42) in its head region at least one annular recess (78) for producing an electrical contact (98) on a contact (44) and have over their axial Extension of an insulating sleeve (76) are enclosed. 11. Fuel injector according to claim 10, characterized in that in the end face (50) of the cover cap (14) a ring (88) is formed which the insulating sleeve (76), the openings (56) in the sleeve body (16) and openings ( 84) in the sealing disc (24), seals. 12. Fuel injector according to one or more of the preceding claims, characterized in that the cover cap (14) has a preformed, integrated return (22) and in the cover cap (14) formed contacts (44) as contact semi-circuits (94) are formed , which allow a rotation of the cap (14) relative to the heads of the connector pins (42) in a rotation angle (90).