Injection nozzle for metering two different viscous materials to produce electromagnetic seals has a base part and nozzle supplied with different materials

The present invention relates to an injection nozzle and a dosing unit for the metered dispensing of a from at least two respective different physi cal and / or chemical properties having vis kosen media existing strand according to the preamble of claim 1 and 11 and a with of the injection nozzle or the dosing can be produced more functional Combination seal according to the preamble of claim 24th

In the field of metering technology are already computer controlled systems (CNC) systems for dosing under known differently-art materials. In this area is the dispensing, ie a dosing or application, of electromagnetically compatible seals from be particular importance. These seals a with electrically conductive ingredients mixed sealing material in the plastic state on a sealing surface on carried.

The importance of products and services to Securing elektrom agnetischen compatibility (EMC) will in the coming years is expected to strongly to grow. Because electronic components generate most electromagnetic interference, the one by column Device housing can escape. To ver prevent that act as noise electroma netic waves escaping from the housing and in a Other housing penetrate the joint surfaces of the be Housing by so-called electrically conductive like tions sealed. This also conductive executed Casing acts in conjunction with the conductive you tion as a Faraday cage. This requirement is in forth any event from the EMC Directive 89/336 / EEC in front.

In addition to the shielding of electromagnetic interference radiation is another essential feature of such Seals in the protection of electronic devices from the Exposure to dirt particles, moisture or same.

Such electrically conductive gasket is in for example from DE 43 19 965 C2 forth. At this Seal in an elastic sealing material conductive particles, eg. as silver grains introduced, these conductive components are expensive and the particular to a reduction of elasticity of the seal to lead. In addition, these substances cause a significant He increase of the specific gravity and cost of the Poetry. It will therefore endeavor to share conductive components in the seal ge possible ring to hold, which in turn reduce the Leit has capability of the seal result.

An apparatus for extruding a dose of a viscous medium formed strand of material is DE 196 47 015 C1. The apparatus comprises a piston pump, wherein the extrusion stroke of the is precisely controlled piston by the piston pump a hydraulic fluid with a gear pump hydrau is cally coupled. The gear pump used there has a high constancy of the capacity and thus also of the extruded strand, wherein also the Be beginning the discharge of the strand precisely controllable is. This device is therefore particularly suitable for extrusive applying a seal on a docu ge.

A means of coextrusion produced electrically leit enabled, two or more layers formed seal is further known from DE 197 33 627 C1 ge been. This seal is simultaneously extruders decoding a core and an electrically conductive To sheathing produced. Here are different vorlie union strands from a separately pasty lowing feedstock from a mobile Koextru sion head on a movable base (Dichtflä che) applied in a single operation.

A similar method for producing a a Ge housing electromagnetic shielding gasket ela and-elastic conductive starting material is in the DE 43 19 965 C2. Also in this method , the conductive sealing material in a pasty Initial state by means of pressure from a single nozzle, the above to be sealed during the geometrical each housing section is guided to this Section applied directly.

In the pre-registered patent application DE 199 42 219.2 is also a method for operating such a Prior device is disclosed in the independent of the traverse speed of the nozzle is always consistent Amount of viscous medium is applied. this will achieved in that the amount of medium proportio nal is applied to the velocity of the nozzle and in dependence on the acceleration or deceleration increase or decrease of the nozzle. This makes it pos Lich, also during application of a circular string to ensure a constant strand cross-section. Preferably, the amount sprayed is proportional the amount, multiplied by a factor sum of the speed of the nozzle, of A by a factor acceleration multiplied with the nozzle and the egg nem another factor multiplied speed square of the nozzle to promote.

The devices and methods mentioned have the Disadvantage that the different physical and / or chemical properties of the used Me serving not sufficiently taken into account and thus the mechanical quality of the discharged strands (Seals, etc.) is in need of improvement.

Depending on the used conductive Parti cles changes the material behavior of sealants to a considerable extent. For instance, the cured leit enabled seal coat only a small Eigenelas ticity. At the same time for the dosage increases the material decisive parameter viscosity, ie the elastic base material is - compared with its original features - much tougher. It also comes in the case of particles with such. B. elec trically conductive particles such as silver particles, highly charged which media propagated to subsequent precipitation of these Particles.

The known devices also do not allow, a low viscosity, particle-free sealing medium and a In contrast, high viscosity, due to containing NEN particles dosed highly abrasive leading medium precise and thereby a uniform strand yielding equal temporarily deploy or aufzutra on a backing gene.

Further, the known prior art dispensing systems suitable only for simple sealing threads generating (sealing beads), wherein the strand diameter not be varied during the discharge of the strand is.

In addition, allow the known devices not a wide range in size of the seal optimal shape and connection of sealing core and seal coat.

come, particularly in the field of mobile electronics increasingly thinner walled housings. As In games are cited here only laptops and mobile phones. Especially with these devices is a reliable waterproofing processing and EMI shielding required. This relatively dimensionally unstable housing have particularly strong vari stituent contact forces on along a seal groove, which often leads to the seals no longer be abut the housing parts and thus a single or no longer verhin radiating interference effect changed is.

The invention is therefore based on the object, a to provide apparatus of the aforementioned type, wel che avoids the disadvantages mentioned and in particular a higher dosage accuracy and volume or Volu menstromkonstanz provides and thus a Qua produced quality increase of the device Strands. The device is also as simple as possible be and inexpensively implemented and operated.

This object is achieved by the features of inde dependent claims. Further and advantageous Embodiments are in the dependent claims and the Be scription refer to.

pre propose The special feature of the present invention NEN injection nozzle lies in that a a nozzle peak exhibiting nozzle base and at least one arranged in the interior region of the nozzle base portion Injek tion needle are provided, wherein the nozzle base and the at least one injection needle with each egg ner's fuel pump are connected. This has the particular advantage that the flow rates of both Medicare s are independently adjustable.

Preferably the Dü containing the injection needle scorching around part in at least two spatial directions traversing bar constructed, which also complex spatial strand gradients Kings will take place in one operation NEN.

According to a further embodiment, the discharge söffnung the at least one injection needle, in We sentlichen relative to the central axis of the nozzle base partly, in a distance from the discharge outlet of the nozzle placed top of the nozzle base portion. This will a compound of at least two media to Nozzle base, thus making it the homogeneity of total discharged strand improved.

The distance between the at least two Austragsöff openings is advantageous from adjustable formed, which on the compound of at least two Media targeted influence can be exerted. For be agreed media processed in large quantities who the are also fixed predetermined injection nozzle as Injection molded parts possible.

The present invention also proposed Dosierein unit has a particular said injection nozzle on. Preferably, the injection nozzle and the In is jektionsdüse associated feed pump at a minimum Distance from one another. This has the advantage, particularly that the viscous and / or for Partikelausfäl ment prone medium (see explanations below to) over very short paths to the injection nozzle can be performed.

Preferably, the injection nozzle and the Injekti are onsdüse associated feed pumps as in at least two spatial directions movable assembly formed. Due to the compact design and said traverse bility is the freedom of movement of the entire Before direction increases, so that complex spatial Off procedural mission paths without any restrictions can be and the device for example in a CNC system can be integrated to the entire From tragungsprozess to fully automate.

According to one embodiment, the at least two Reservoir for storing the by Injekti onsdüse be discharged media and the injection nozzle associated feed pumps also in a mini painting distance from one another, which just if in a ver in at least two directions in space can be arranged mobile unit. hereby the freedom of movement is increased even further.

According to a particularly advantageous embodiment are respectively the flow rate and / or the delivery pressure regardless laying a least two media of each other adjustable, in particular also during the Operation of the apparatus. This is the extrusion process in both media independently influenced where when the two material flows even under each different times on and can be parked. When starting a sealing bead z. B. is first Man telmaterial and then promoted nuclear material. At the end the sealing bead, the core material is first stopped and only after the shell material. Thus it is enough that nichtleit nowhere on the sealing bead capable nuclear material comes out of the shell surface. Thus the koexrudierte strand cross-section is not än changed, be in continuation to DE 199 42 219.2, to which in the present context fully respect is taken, the equations described therein on both media applied, bringing together the following hang results:

Pump speed 1 (pump 1) + pump speed 2 (Pump 2) =Volume factor M1 (material 1). [Speed Nozzle + accelerating Düse.Faktor A1(Material 1) + Geschwindigkeitsquadrat.Faktor B1 (Material 1)] +Volume factor M2 (Material 2). [Speed Nozzle + accelerating Düse.Faktor A2(Material 2) + B2 Geschwindigkeitsquadrat.Faktor (Material 2)]

About the Proportionali called quantity factor tätsfaktor can each be discharged quantity of both Media are determined, ie, whether the discharged strand proportionately more material 1 or 2. The Ge samtmengenfaktor M1 + M2 can be determined whether the Strand is total thicker or thinner. Holding the Total factor M1 + M2 constant, then one can Ratio M1: M2 adjust.

The respective factors A serve to compensate for dy namic material properties of the two auszubrin lowing media and compensate in particular the non- Newtonian behavior of the media be discharged. The relevant factors B should compensate VELOCITY keitsabhängiger nonlinearities, for example, by leaks in the pump and by the viscosity the media be discharged may arise.

Factors A1 and A2 and B1 and B2 of the least two materials can also be different and for example, by means of at least two Materials carried out preliminary experiments to optimize and the respective materials to be adapted.

In addition, it can be provided that the nozzle base and / or from the nozzle base and the nozzle due in part associated pump assembly formed are rotatably mounted respectively, where the angle of rotation gesteu relative to the direction of the injection nozzle is ert adjustable. Especially in the case of benefit Textured discharged strands, it is necessary to least the angular position of the profiled injection nozzle relative to nachzu already discharged strand drive.

In addition, the injection nozzle according to the invention allow and the metering producing strands (Seals or the like) with arbitrarily varying to dispen ratios of filler rod to rod jacket sen.

Also can be identified by the at least two Förderpum pen transported volume currents proportional to a Än ation of the feed rate of the injection nozzle change or the dosing or to reflect the change to adjust.

Furthermore, the invention enables metering a particularly homogeneous structure of the discharged Strand. Thus, when starting the Dispensprozesses be promoted disproportionately more material than this after reaching a set Vorschubge speed is necessary, and, in contrast, in Moment of stopping a disproportionately lower Amount to be promoted material. This makes the Forming a stronger seal or end of a Blob effectively avoided.

It is understood that instead of a method Injection nozzle or the dosing also about existing Werkstückhalter- or table relative to these can be moved, or even a Kombina tion this be traversed is given.

The invention further proposed mehrfunktio dimensional combination seal with at least one of ei nem first cold elastic medium formed core strand and surrounding the core strand outer strand of egg nem against the first medium physically and / or chemically different second media offer in particular by the strand cross-sectional plane and / or the strand length from varying structure. It can be therefore particularly in thin-walled Appliance housings adjustments to the seal at the jeweili gen Anpressdruckverhältnisse or the like vorneh men.

It should be noted that the different physika metallic and / or chemical properties, in particular the outer strand at electrical conductivity are limited, but certainly also a magnetic Shielding, for. Example, using iron particles, or the like. The mechanical properties th particular the outer strand may also particularly waterproof or acid-proof properties or the same include.

The invention is further based on in Zeichnun gen embodiments shown in more De tail explains that make up the in conjunction with Claims other characteristics, features and advantages the invention result.

Specifically:<b>Fig.</b> 1 is a perspective overview drawn egg ner constructed in compact design Dosierein unit according to the invention;

<b>Fig.</b> 2 shows a lateral section through the center of Lach se an injection nozzle according to the invention for Discharge of two different materials;

<b>Fig.</b> 3 is a <b>Fig.</b> 2 corresponding Schnittan view of a three-part injection nozzle in accordance with the invention;

<b>Fig.</b> 4a - f construction variants of erfindungsge Maessen injection nozzle;

<b>Fig.</b> 5 is a combination of two dosing pumps for Mate rialtransport a second medium to a Injection nozzle according to the invention;

<b>Fig.</b> 6a, b a side view of a. Plan view and a b. a drive unit of fiction, proper dosing in Schnittdarstel ment;

<b>Fig.</b> 7 a pneumatic circuit diagram of a erfindungsge Maessen dosing; and

<b>Fig.</b> 8 an embodiment of the inventions to the invention device produced multi functional combination seal shown, in a housing part.

In the <b>Fig.</b> 1 shown constructed in compact design single dosing is on a housing <b>10</b> angeord net, in the (not shown here) electronic compo le are arranged to protect against external influences. In a frame part <b>20</b> is a cartridge <b>30</b> angeord net, preferably auszutra for storing a ing material (medium) having a high viscosity or high loading of solid particles is used. by means of a cylinder <b>40</b> the material from the cartridge carried out and a feed pump <b>50</b> supplied. From the feed pump <b>50</b> enters the material eventually in an injection nozzle <b>60</b>, Due to the compact Design subject of the work area or the United travel distances only minor restrictions.

The spreading of each separately pasty present Starting materials in the form of a strand takes place with means a drawn in the figure in the x-, y- and z axes are each independently movable (here not shown) drive mechanism, namely insbesonde re in a single operation.

The in <b>Fig.</b> 2 injection nozzle shown schematically <b>100</b> has a nozzle tip <b>105</b> and one within the nozzle tip <b>105</b> centrally arranged injection needle <b>110</b> on. The discharge<b>120</b> the injection needle <b>110</b> is at a distance h to the discharge <b>130</b> the Dü senspitze <b>105</b> arranged. To a combination train from z. B. Leitmittelstrang with internal sealing material strand manufacture, is in an existing, on the way <b>150</b> directed stream from at example electromagnetically shielding called EMC material a second, on the way <b>140</b> guided Stream injected from, for example, silicone. Likewise, of course, there is the possibility that two material flows through the complementary way to flow to an enclosure so that a sealing material strand (eg., silicone) with a Leitmittelstrang produce (z. B. EMC material).

The in <b>Fig.</b> 2 distance h shown is either variable (S. Also <b>Fig.</b> 3) or, to a predeterminable value For example, a erge from a series of experiments inputting optimum value to achieve the respective Be fixed quality standards in order particu more mass production, eg. as an injection molded part, the injection nozzle <b>100</b> to enable.

<b>Fig.</b> 3 shows also schematically an Schnittan view along the central axis of a three-piece set built injection nozzle. One of the in<b>Fig.</b> 2 with <b>105</b> be recorded nozzle tip similar nozzle tip <b>205</b> is in the example releasably with a nozzle base <b>200</b> ver prevented. At the nozzle base<b>200</b> is a nozzle tip <b>205</b> via a thread <b>220</b> detachably secured to a Var Center of the distance h to allow. The three individual parts <b>200</b>. <b>205</b>. <b>210</b> can without difficulty in very small dimensions are produced, thus what the Production of very fine injection nozzles allowed. Also there is a possibility all three parts in a construction summarize part and serial production the Po define positions.

In the nozzle base <b>200</b> is laterally horizontally through an opening <b>230</b> introduced the first material (eg. B. Silicone) deflected by 90 degrees. It is noted that the first material thereby however obliquely from can be introduced above. By the nozzle base part <b>200</b> Inappropriate injection needle <b>210</b> is then first material in the direction of the material flow of through an opening <b>240</b> imported second material (Z. B. EMC material) passed and at the discharge <b>250</b> the nozzle tip <b>205</b> discharged, so that the second Stream the first stream of material completely around closes.

With a diameter of the discharge opening <b>250</b> the Dü senspitze <b>205</b> of 3 mm, the preferred distance between said outlet opening <b>250</b> and the Top side of the substrate 3.3 to 3.4 mm. This is ensures that the cross-section of the discharged Strand and the opening shape of said off exit opening <b>250</b> equivalent. For shorter distances is to the ground from a circular aperture shape of outlet opening <b>250</b> a flat oval rope form what in some applications it may be desirable even.

In the <b>Fig.</b> 4a - 4f are different variants the injection nozzle shown. The variation possibilities as regards the distance h of the discharge <b>120</b>. and <b>130</b> each based on different Setting the needle on the one hand (S. Example a.) And the nozzle tip and the nozzle due partly the other part (s. Example b.). Prefers an adjustment of the distance h on the Düsenspit ze (Example b.) made since the setting possibilities speed of the needle more difficult because of their shape is to accomplish. can depending on the application However, all of the versions shown or with the sen similar or equivalent arrangements in question come.

The <b>Fig.</b> 5 shows an arrangement of two feed pumps <b>300</b>. <b>310</b>Wherein one of the feed pump <b>300</b> funded first material directly an injection nozzle <b>320</b> is supplied from the feed pump and a <b>310</b> geför engineered second material via a connecting line <b>330</b> the injection nozzle <b>320</b> fed only indirectly becomes.

According to the in <b>Fig.</b> promotes 3 shown injection nozzle the pump <b>300</b> Material in the outer nozzle space of Dü senspitze <b>205</b>Whereas the pump <b>310</b> Material in the Injection channel of the injection needle <b>210</b> promoted. The se arrangement is therefore especially suitable for Materi alkombinationen in which a viscous but with Par cles unloaded sealing material on the way forward via the connecting line <b>330</b> in the injection nozzle <b>320</b> is performed, whereas a with solid particles (High) loaded conductive material over the short distance of the pump <b>300</b> directly into the nozzle tip <b>320</b> Gelei tet is. The two pumps<b>300</b>. <b>310</b> can however arranged side by side or one behind the other be.

In the <b>Fig.</b> 6a illustrated side view of the Dosing certain drive unit has a electric motor <b>400</b>, Of a motor mounting plate <b>410</b> on a transmission block <b>420</b> is attached. A rotor wave <b>430</b> of the electric motor <b>400</b> engages in a egg from ner screw <b>440</b> and a worm wheel <b>450</b> formed A worm drive, the worm <b>450</b> in turn with a means of a ball bearing <b>460</b> mounted on drive shaft <b>470</b> is rigidly connected.

The rotor shaft <b>430</b> engages in a 3-course Screw, which the corresponding worm wheel drives. The worm gear causes the one hand, Force deflection at 90 degrees, on the other hand, a reaction in proportion 10: 1.

In the <b>Fig.</b> 6b illustrated plan view of of driving devices unit is a means of a gear intermediate gear <b>480</b> from the drive shaft <b>470</b> driven Abtriebswel le <b>490</b>Which, by means of a ball bearing <b>500</b> is mounted. The worm <b>450</b> then drives the drive shaft <b>470</b> the intermediate gear to which has the task of the to split the power flow into two equal parts and these the gears of the respective conveying or Dosierpum pe dispense.

The drive unit is of compact design, in Block form, realized. In the block are Pumpenaufnah me, intermediate gear, worm drive for reduction and motor receiving summarized. This will short paths of power transmission implemented.

The <b>Fig.</b> 7 shows a pneumatic circuit diagram of the Do siereinheit. The for the dosing process for the Mate rialtransport from the cartridge required cartridges is residual pressure by a double acting Pneuma tikzylinder <b>600</b> provided. It is sicherzu provide that the cartridge form in the moment is, in the start up of the pump drive, and that the Cartridges form when stopping of the pump motor so continued falls again. This is accomplished by a 3/2-way solenoid valve <b>610</b> in interaction with a Schnellent Fan <b>630</b> ensured. The pressure builds up here abruptly through a silencer <b>640</b> from. The Ma solenoid valve <b>610</b> receives the signal to open directly from (not shown here) Motor control electronics. A further 3/2-way valve <b>620</b> in button version used to manually retract the cylinder piston in a cartridge change. numeral<b>650</b> called a manometer and <b>660</b> a throttle valve, which for Preset position of the hydraulic circuit shown at the applied pressure p_in serve.

Finally shows the <b>Fig.</b> 8, a housing part <b>700</b>, in one more functional combination seal <b>710</b> be already been applied. The housing part<b>700</b> has a Number of counterbores <b>720-770</b> by means of which the housing part <b>700</b> with a (not shown here) second housing part, for example by means of threaded joint is bonds or the like connectable.

The combination seal <b>710</b> is by coextrusion mi means a prescribed device from a Sealant strand <b>780</b> and a Leitmittelstrang <b>790</b> ge forms. By changing the nozzle geometry and variation the discharged amounts, the strength of the seal material strand and the independent Leitmittelstranges be determined from each other. Here the innenlie is lowing sealant strand in sealing dünnwan -ended enclosures or, as in this example, in Housing sections with low Verschließkräften, z. B. in the area of ​​section line AA, or large auszuglei relevant tolerances with a relatively large diameter educated. By contrast, the combination seal<b>710</b> in housing areas with high Verschließkräften, z. B. in the area of ​​section line BB, with a relatively formed small diameter. It also can Value Volume (Leitmittelstrang) / Volume (sealant strand) are adapted so that for example. The elastic Properties of the combination seal in all Housing sections are optimal.

The relatively low proportion of metered elec trically conductive particles also affects weight- and cost-reducing effect.

The enlarged detail shows along the two Section lines AA and BB produced cross-sectional areas the combination seal shown. In addition to ge showed embodiments, however, are also (here not shown) variations of the ratio to coat Core possible.

When sealant is an elastomer, preferably a Silicone elastomer, into consideration, which at room temperature and a certain humidity in the form of an ex trudi Erten strand (caterpillar) dimensionally stable to an elastic rule, adhering seal hardens. In principle, all permanently elastic curing sealants, as in for example silicones, polyacrylates etc., using find.

As a conductive agent are solid materials (fillers) used, preferably metal particles or Metal working coated particles, z. B. silver grain, silver plated Me tallow or glass particles, soot particles or copper Parti kel or copper-clad glass particles.

It is understood that the device described above also include for the preparation of a plurality of core strands the strands can be used, in which case the In zone region of the nozzle base portion <b>200</b> two or more needlestick <b>210</b> are arranged, which preferably trainees through different delivery pumps each bearing material to be supplied. an application examples game is a more functional combination seal, the outside has a Leitmittelstrang and inside two adjacently arranged sealing means strands with each having a different elasticity.