DE102020206378B4 - Process for manufacturing a ventilation louvre with sound-absorbing foam - Google Patents

Abstract

Method for producing a rear ventilation lamella (100) of a ventilation unit (210) with front and rear ventilation lamellas (100) for a ventilation register of a motor vehicle, using a combined separation injection molding tool (300) with a first tool half (303) and a second Tool half (304), having the following steps: - Inserting a first component (110) as a flat, foamed foam material (115) between the two tool halves (303, 304), - Closing the two tool halves (303, 304) and punching out a recess (111) in the Foam material (115) in a first molding step (301), wherein an intermediate product (130) is produced,- moving the intermediate product (130) from a first position to a second position within the combined cut-off injection molding tool (300), or stationary Holding the intermediate product (130) in position within the combination cut-off injection molding tool (300)- closing or r holding the two tool halves (303, 304) closed in a second molding step (302), - injecting a second injection moldable material (122) to form a second component (120) while a cutting device (307) of the combined separation injection molding tool (300 ) separating a region of the first foam component (110) along an outer border (112) to expose a pore structure inside the first foam component (110), and removing the rear ventilation lamella (100) from the separating injection molding tool (300) .

Description

The invention relates to a method for producing a rear ventilation slat of a ventilation unit with front and rear ventilation slats for a ventilation register of a motor vehicle, using a combined separating injection molding tool according to claim 1 and claim 7.

the DE 10 2013 212 420 A1 relates to a process for the production of an at least partially translucent molded body which has at least one light-reflecting area, a thermoplastic polymer being injected into at least one cavity of a mold and a film in the mold being connected to the thermoplastic polymer and a microstructure being incorporated into the mold by means of a microstructured mold area foil is embossed. The foil is pressed against the microstructured mold area by an internal mold pressure of at least 400 bar. the DE 10 2013 212 420 A1 also relates to a molded body which consists at least partially of a thermoplastic polymer and is at least partially translucent, and a film which is at least partially connected to the base body and has at least one light-reflecting area and is provided with a microstructure. The foil comprises a mirror foil and the thermoplastic polymer is doped with reinforcing agents.

the DE 38 00 438 A1 relates to a decorative buckle z. B. for belts, which consists of a buckle body at least partially covered with a flexible reference material. The buckle body is designed as a one-piece core with an upper side and an underside, with a blank made of the cover material being arranged on each side. In terms of surface area, the cover material blanks are designed to be larger than the core in such a way that they protrude beyond the core with an edge. At least in the region of the edge of one of the blanks, there is an adhesive coating via which the blanks, including the core, are connected to one another in a materially bonded manner. Furthermore, the DE 38 00 438 A1 a device for producing the decorative buckle, wherein a lower tool and an upper tool have pressing surfaces facing one another, and a receptacle adapted to the buckle body is formed in one of the tools in the region of its pressing surface.

• eine erste Form und eine zweite Form, welche die Basis formen durch Einspritzen von geschmolzenem Harz in einen Basis-Form-Raum, welcher in einem formgeschlossenen Zustand der ersten und der zweiten Form ausgebildet ist;
• sowie eine Vakuum-Form zum Vakuum-Formen der Haut, wobei, wenn die Vakuum-Form, an welcher die geformte Haut angebracht ist, mit der ersten Form Form-geschlossen wird, ein Schaum-Raum zwischen der Haut und der Basis ausgebildet wird/ist,
• wobei ein Einspritz-Kanal zum Einspritzen des geschmolzenen Harzes in den Basis-Form-Raum sowie ein Schaum-Flüssigkeit-Einspritz-Kanal zum Einspritzen der Schaum-Flüssigkeit in den Schaum-Raum in der ersten Form vorgesehen sind, so dass die erste Form zusammen mit der Vakuum-Form als eine Schaum-Form verwendet wird.

An apparatus for making a foam-layer crashpad by injecting and foam-forming a foam liquid between a base and a skin is disclosed in US Pat DE 10 2012 110 419 A1 disclosed. The device features:

• a first mold and a second mold that mold the base by injecting molten resin into a base mold space formed in a mold-closed state of the first and second molds;
• and a vacuum mold for vacuum-forming the skin, wherein when the vacuum mold to which the formed skin is attached is mold-closed with the first mold, a foam space is formed between the skin and the base/ is,
• wherein an injection port for injecting the molten resin into the base mold space and a foam liquid injection port for injecting the foam liquid into the foam space are provided in the first mold so that the first mold together used with the vacuum mold as a foam mold.

the DE 10 2016 109 033 A1 discloses a molded component and a method of making the molded component. The molded component is a door panel, on the outer side of which a fastening element is fastened by means of welding, ie probably by means of plastic welding. With the DE 10 2016 109 033 A1 a method is to be specified with which less material is used in the welding process of the plastic elements, the weight of the molded component, ie the door panel, being reduced as much as possible. For this purpose, a base component has a skin, which is arranged on the inside of the vehicle, and a smoothing layer, which is arranged on an outer side lying opposite thereto. The base component is formed from a fiber composite material. A bracket, for example a clip seat, is connected to the smoothing layer. For this purpose, an injection unit is used to inject material into a hanger mold space of a mold, so that the smoothing layer and the material of the hanger are bonded. Although treated the DE 10 2016 109 033 A1 in a certain way a plastic injection molding, but the production of a ventilation lamella, in particular a rear ventilation lamella, is not discussed.

Also the DE 10 2013 109 066 A1 deals with the production of a crash pad, whereby a ventilation lamella is not mentioned. the U.S. 3,909,169 A is concerned with the manufacture of articles having a skin of one material and a core of dissimilar material thereto, particularly describing apparatus suitable for carrying out. A board with a foamed core and an unfoamed skin could thus be produced.

In the field of motor vehicles, the ventilation of the vehicle interior plays an important role in driving comfort and passenger safety. It is precisely the intensive ventilation for de-icing windows that often causes an unpleasant volume in a motor vehicle. Ventilation units, in particular also the ventilation slats of the ventilation units, must therefore be designed with sound-absorbing or sound-damping material for improved driving comfort. Sound deadening materials typically consist of a porous structure that converts sound energy into heat due to frictional forces between sound waves and the cell walls in the porous structure.

Molded parts such as ventilation slats for the ventilation units in the interior of a motor vehicle are often made from an outer skin-foam-carrier composite. A foam layer is provided between an outer skin, which forms the accessible visible and tactile outside of the molded parts, and a carrier element. In the production of such molded parts, a foam-forming plastic is introduced into an intermediate space between the outer skin and the carrier element. The introduced, foam-forming plastic evenly fills the space between the outer skin and the carrier element. During this so-called back-foaming, the carrier element is held in a first part of the foaming tool and the outer skin is held in a second part of the foaming tool.

In such a manufacturing process for molded parts, areas in which openings are later required, such as openings for ventilation screens, are initially back-foamed over the entire surface. In a subsequent step, these areas that are not required are milled or punched out as openings using a suitable cutting technology.

Also known from the prior art is the S-FIT technology (Soft Foam Injection Technology), in which a molded part can be manufactured from two different materials in one work step. A carrier made of thermoplastic material is first injected into a closed mold and then a three-dimensional structure is produced, for example by a "core-back" process, with recesses being created. A previously vulcanized gasket is then attached to this beam using the residual heat from the beam that has just been manufactured. (https://www.sumitomo-shi-demag.eu/processes/s-fit.html accessed on February 22, 2018)

Injection molding processes can also be carried out as foam injection molding processes and can also be extended to thermoplastic elastomers. Good foam structures can be achieved by chemical and physical foaming, e.g. with polypropylene and polyamide (http://www.plastics.gl/injection-moulding/foam-injectionmolding, accessed on November 15, 2018).

In the state of the art, further comparable manufacturing processes, in particular for ventilation units with sound-absorbing material, are already being used in motor vehicles. Various ventilation units or other molded parts with sound-absorbing material are also described.

the US 2008/0 096 481 A1 relates to a cooling fan device for a motor vehicle, the housing or individual components, in particular the ventilation grilles at the air inlet and air outlet, having a sound-absorbing, large-pored foam, for example polyurethane or polyester.

the U.S. 6,767,050 B2 concerns an isolator panel between the engine compartment and the dashboard to dampen noise and vibration from the engine compartment. The insulator panel consists of two layers, namely a layer made of an elastomer and a layer of a thermoplastic olefin. Both layers are connected to one another by V-shaped tabs in the elastomer layer, which engage in corresponding depressions in the thermoplastic layer.

In the US 6,071,591A discloses an automotive vehicle instrument panel having a thermoplastic surface, an injection molded thermoplastic polyurethane body, and at least one air duct integrally formed with the instrument panel body. The air duct is made by means of a removable insert as a recess body, in particular an inflatable air body. After removing the recess former, the air duct is filled with thermoplastic polystyrene.

the US 6,023,938A relates to an air conditioner in which the open grille structure normally placed directly in front of a condenser unit is replaced by an acoustic barrier placed in front of the condenser unit. The structure of the acoustic absorption material defines the air flow path to the condenser unit. The modified air flow path results in a modified sound path, which in turn results in sound attenuation. The acoustic absorption material may consist of open cell foam and fiberglass mats and may have a surface treatment to protect against environmental influences.

In the article by MOHD MOESLI et al., The Effect of Air Gap Thickness on Sound Absorption Coefficient of Polyurethane Foam, Defense Sand T Technical Bulletin, November 2012, the effects of a second sound-absorbing layer behind a layer of polyurethane foam on the sound absorption coefficient are discussed examined for low-frequency and high-frequency noise. Polyurethane foam is widely used in soundproofing technology to absorb sound. The results of the work show that introducing an air gap behind the layer of polyurethane foam increases the sound absorption coefficient, especially for high-frequency sounds.

In the U.S. 8,470,217 B2 discloses a foamed molding for use in dashboard, door inner panel or vehicle floor. It features both a foam with greater tear resistance and sound-absorbing material. Thus, the application for these moldings also extends to structural members of an automobile, which require both a silencing effect and strength. Furthermore, a surface layer is provided on such a molded part as a sound-absorbing protective layer with a reduced porosity. At this time, the thickness of a surface layer is preferably 10 to 45% of the total thickness of the foamed article.

the EP 2 335 900 A2 also relates to a method for producing a skin-foam carrier composite for a molded part for the interior of a vehicle, having a carrier that is elastically deformable, at least in some areas, from a thermoplastic, in particular from polypropylene, and is applied to a first foaming tool part of a foaming tool in a form-fitting manner . A skin, for example made of the thermoplastic polyurethane, is applied to a second foaming tool part of the foaming tool in a form-fitting manner. The first and second foaming tool parts are moved toward one another to form a cavity between the skin and the carrier, with at least one contoured projection of the second foaming tool part pressing the skin into the carrier in a sealing manner. Furthermore, after the foaming tool parts have been moved toward one another, a liquid, foam-forming plastic is introduced into the resulting cavity, which fills the cavity between the skin and the carrier and then hardens.

the US 6,207,090 B1 relates to a method of making a film-covered article. A movable press having first and second shell molds is moved to an open position with the first shell mold having a sealing surface and the second shell mold having a cutting surface. A thin, flexible film formed of thermoplastic material is positioned between the first and second mold shells. When the shell molds are locked together, thermoplastic resin is injected, which adhesively bonds to the film. In doing so, a portion of the film also remains sandwiched between the sealing and cutting surfaces and acts as a seal between the mold halves.

In the US 2008/0012166 A1 a foamed part is produced using “core-back” technology, in which an expandable resin with a foaming agent is filled into a cavity between a stationary mold half and a movable mold half. By moving the mobile mold half away from the stationary mold half, the volume of the cavity is expanded until it matches the size of the molded foamed resin product. The speed of movement is thereby controlled to provide a resin product having a skin layer over the entire surrounding surface and a homogeneous foam structure under the skin layer.

Given the state of the art presented, there is still room for improvement. In particular, the design of the production method for producing a ventilation lamella can be further simplified.

The object of the invention is to reduce the noise caused by a ventilation unit and to provide a cost-effective manufacturing method for such a ventilation unit.

According to the invention, the object is achieved by a method for producing a rear ventilation slat of a ventilation unit with front and rear ventilation slats for a ventilation register of a motor vehicle, using a combined separating injection molding tool with the features of claim 1 and claim 7. Further, particularly advantageous configurations of the invention are disclosed in the dependent subclaims.

It should be pointed out that the features and measures listed individually in the following description can be combined with one another in any technically meaningful way and show further refinements of the invention. The description additionally characterizes and specifies the invention, in particular in connection with the figures.

• - Einlegen einer ersten Schaumkomponente als flächiges, geschäumtes Schaummaterial zwischen die beiden Werkzeughälften,
• - Schließen der beiden Werkzeughälften und Ausstanzen einer Ausnehmung in dem Schaummaterial in einem ersten Formungsschritt, wobei ein Zwischenprodukt erzeugt wird,
• - Bewegen des Zwischenprodukts aus einer ersten Position in eine zweite Position innerhalb des kombinierten Abtrenn-Spritzguss-Werkzeugs, oder ortsfestes Halten des Zwischenprodukts an seiner Position innerhalb des kombinierten Abtrenn-Spritzguss-Werkzeugs,
• - Schließen der beiden Werkzeughälften in einem zweiten Formungsschritt,
• - Einspritzen von einem zweiten spritzgussfähigen Material zur Ausbildung einer zweiten Komponente während eine Schneidvorrichtung des kombinierten Abtrenn-Spritzguss-Werkzeugs entlang einer äußeren Umrandung einen Bereich von der ersten Schaumkomponente zum Freilegen einer Porenstruktur im Innern der ersten Komponente abtrennt, und
• - Entnehmen der hinteren Belüftungslamelle aus dem Abtrenn-Spritzguss-Werkzeug.

The invention relates to a method for producing a rear ventilation slat of a ventilation unit with front and rear ventilation slats for a ventilation register of a motor vehicle, using a combined separating injection molding tool with a first tool half and a second tool half, having the following steps:

• - Inserting a first foam component as a flat, foamed foam material between the two tool halves,
• - Closing the two tool halves and punching out a recess in the foam material in a first molding step, with an intermediate product being produced,
• - moving the intermediate product from a first position to a second position within the combined cut-off injection molding tool, or holding the intermediate product stationary in its position within the combined cut-off injection molding tool,
• - Closing the two mold halves in a second forming step,
• - injecting a second injection moldable material to form a second component while a cutting device of the combination cut-off injection molding tool cuts off a region of the first foam component along an outer perimeter to expose a pore structure inside the first component, and
• - Remove the rear ventilation lamella from the detachable injection molding tool.

The ventilation lamella can be designed as an inner ventilation lamella. The first foam component, also referred to as a foam seal or simply the first component, is formed, preferably with the aid of a chemical foaming agent, and in the cured state has a porous sound-damping structure by breaking the air flow like a comb. Such a structure can also be achieved or reinforced by a correspondingly designed surface. On the one hand, this structure can be provided by sink marks on the surface of the cured first foam component. On the other hand, an open-pored or coarse-pored structure can be exposed in the interior of the first foam component by foam material being separated from the first foam component in certain areas to form a cut surface in a second molding step. The pore structure of the foam is exposed at the cut surface, which creates the sound-absorbing effect. In the prior art, the first foam component is typically formed with rubber. The first foam component according to the invention can be formed, for example, with polyurethane, in which case the foam material for the production process can be provided as a pre-foamed or already completely foamed mat-like roll material.

The second component, also referred to as the foam carrier, is designed as a carrier component for the ventilation lamella for assembly on the ventilation unit. For this purpose, the second component has fastening elements, which are simultaneously designed, preferably designed as pivoting elements, for deflecting the draft of air from the ventilation duct. In principle, any suitable material that is dimensionally stable in the cured state and fulfills the carrier function of the first foam component can be used for the carrier function. The first foam component is formed first and, after curing, is overmoulded or back-moulded by the second component. This creates a firm connection between the first foam component and the second component. Alternatively, the second component can be formed first and, after curing, be overmoulded or back-moulded by the first foam component.

In the first shaping step, the foam material is already pre-foamed, preferably as a semi-finished product or foam roll, and introduced into the separating injection molding tool, and a recess is then formed within the foam material.

Foamed, mat-like cut polyurethane has sink marks on the surface and/or has a porous structure on the inside. The polyurethane cut into mats is rolled up as a foam roll. For the production process according to the invention, it can be unrolled again and made available in the separating injection molding tool as foamed foam material for the first foam component. Such roll material can be provided inexpensively as an industrial mass-produced article, which means that the manufacturing costs for manufacturing the rear ventilation louvers can be reduced. Sink marks, which appear to the observer as dents or indentations on the surface of the plastic parts, are typically undesirable on the surface of molded parts. However, the rear ventilation slats cannot be seen or felt by vehicle occupants, or only with difficulty, which is why such a structure for sound absorption can be specifically designed here. The second component is injected into the separating injection molding tool through the recess, so that the first foam component is back-injected by the second component.

The first shaping step preferably takes place as a first separating process for forming the recess by punching with a punching device which is part of a first tool half and/or a second tool half of the separating injection molding tool.

With the punching device, a continuous or interrupted recess can be formed in the first foam component in one work step, for example by moving a first or mobile tool half with a projection for punching towards the second or stationary tool half with a depression complementary to the projection, wherein in the already foamed display material for the first foam component is inserted in the second mold half. As a result, a region is formed which is back-injected or encapsulated by the second component when it is injected. This punching device can also be used to form additional connecting holes in the first foam component, which can also be back-injected or overmolded with the injected, injection-mouldable material of the second component, so that a particularly stable connecting section is formed between the two components in the finished rear ventilation lamella.

For rapid production, the injection-moldable material for the second component can be injected into the recess and the foam material can be separated from the first foam component in the second molding step, in particular at the same time.

As a result, the tool halves of the separating injection molding tool no longer have to be opened between these two work steps. Thus, the time for one cycle for manufacturing a ventilation blade is shortened, and thus the manufacturing cost is reduced. Alternatively, within the second molding step, the mold halves can be opened and the present intermediate product moved by the arms of a robot.

Preferably, in addition, in the second molding step, in the second separating operation, the first foam component can be cut out along the outer periphery with a cutting device and held in position with the cutting device while the second component is injected into a cavity.

By forming the second component in the cavity between the first mold half and the second mold half of the split injection mold and cutting out the first foam component in one molding step, the completion of the finished ventilation louver can be accelerated. There is also no need for an intermediate product to be moved manually or by a robot arm. While the first foam component is being cut out by severing foam material that is not required, it is simultaneously held in position by the cutting device in such a way that it seals the cavity to the outside when the injection moldable material for the second component is injected. This further reduces the manufacturing effort, since additional sealing material is not required.

In an advantageous development of the invention, the first foam component has a higher deformation temperature or softening point than the melting point of the second component.

The second component is typically hot injected. At the same time, the first foam component is formed from a thermoplastic or an elastomeric material, which typically has a limited temperature resistance. By choosing a correspondingly high softening point, the second component can be injected without the quality of the first foam component being impaired. Sufficient pressure resistance to the pressure inside the cavity is also provided. Furthermore, it is provided that the foam seal formed by the first foam component is functional despite the temperature fluctuations in the interior of a motor vehicle over the entire service life of a typical motor vehicle and does not develop any unpleasant odors.

As an alternative to introducing or inserting already foamed foam material into the separating injection molding tool, the foam material can be injected in the first shaping step and foamed and/or expanded by opening the separating injection molding tool.

• - Einspritzen zwei verschiedener spritzgussfähiger Materialien in eine Kavität zwischen den beiden Werkzeughälften, wobei zunächst spritzgussfähiges Material für eine zweite Komponente oder für eine erste Schaumkomponente eingespritzt wird, welches zumindest teilweise aushärtet, wobei anschließend Schaummaterial für eine erste Schaumkomponente oder für eine zweite Komponente in einer durch Vergrößerung der Kavität gebildeten zusätzlichen Kavität eingespritzt wird, und Aneinanderfügen der beiden Komponenten,
• - Öffnen der beiden Werkzeughälften und Expansion der ersten Schaumkomponente unter Einfluss eines chemischen Schaumbildners, wobei nach diesem ersten Formungsschritt ein Zwischenprodukt erzeugt ist,
• - Bewegen des Zwischenprodukts aus einer ersten Position in eine zweite Position innerhalb des kombinierten Abtrenn-Spritzguss-Werkzeugs,
• - Schließen der beiden Werkzeughälften, wobei eine Schneidvorrichtung des kombinierten Abtrenn-Spritzguss-Werkzeugs entlang einer äußeren Umrandung einen Bereich von der ersten Schaumkomponente zum Freilegen einer Porenstruktur im Innern der ersten Schaumkomponente abtrennt, und
• - Öffnen der beiden Werkzeughälften und Entnehmen der hinteren Belüftungslamelle aus dem Abtrenn-Spritzguss-Werkzeug.

The object is also achieved by a method with the features of claim 7, wherein a method for producing a rear ventilation lamella of a ventilation unit with front and rear ventilation lamellas for a ventilation register of a motor vehicle, using a combined separating injection molding tool with a first Tool half and a second tool half, having the following steps is proposed:

• - Injecting two different injection-mouldable materials into a cavity between the two tool halves, with first injection-mouldable material for a second component or for a first foam composition component is injected, which hardens at least partially, foam material for a first foam component or for a second component then being injected into an additional cavity formed by enlarging the cavity, and joining the two components together,
• - Opening of the two mold halves and expansion of the first foam component under the influence of a chemical foaming agent, with an intermediate product being produced after this first shaping step,
• - moving the intermediate product from a first position to a second position within the combined cut-off and injection molding tool,
• - Closing the two tool halves, wherein a cutting device of the combined separation injection molding tool along an outer edge separates a region from the first foam component to expose a pore structure inside the first foam component, and
• - Open the two halves of the mold and remove the rear ventilation lamella from the separating injection molding tool.

In other words, in the first molding step, foamable foam material for producing the first foam component can be introduced into the separation injection molding tool. Injection moldable foam material is also to be understood as foam injection moldable material which is preferably flowable or fluid. Thermoplastic polymers and thermoplastic elastomers are suitable for this. Thermoplastic elastomers based on thermoplastic polyester have a good foam structure, pore structure and surface finish. The foam structure is accurately formed with slow and/or high precision opening of the mold halves and slow to medium injection speed. The second component can be formed in a second injection process by overmolding or back-molding the first foam component as soon as the first mold component has hardened, cooled down or is dimensionally stable. Alternatively, the second component can be formed first and, after it has hardened, be overmoulded or back-moulded by the first foam component.

The first foam component is preferably made open-pored or with sink marks for sound absorption by means of a chemical foaming agent.

The chemical foam-forming agent, which can also be an additional aid to foam formation, causes the first foam component to expand, for example with evolution of gas, when the mold halves are opened. Gas inclusions in the first foam component result in an open-pored or large-pored or coarse-pored or porous structure and/or sink marks, dents or indentations can form on the surface of the first foam component. By separating or cutting off areas of the first foam component, this structure can also be exposed for improved sound absorption.

In an advantageous but optional development of the invention, a cavity in the first molding step and/or in the second molding step to form the first foam component and/or the second component between the first mold half and the second mold half is formed entirely or partially using a core-back process .

A core-back process allows two-component parts to be manufactured without opening the mold halves of the split-off injection mold. The first foam component and the second component are injected into the same cavity one after the other in such a way that when the first and/or the second component is injected, a displaceable insert in the separating injection molding tool closes part of the cavity. When the injection process of the first and/or the second component is completed, the cavity is opened completely by actuating the slide and the first and/or the second component is injected.

• 1a shows a perspective representation of a vehicle interior with a ventilation unit from the prior art.
• 1b shows a perspective representation of a ventilation unit with a ventilation lamella from the prior art.
• 1c shows a ventilation blade from the prior art.

Advantageous configurations of the invention are disclosed in the dependent claims and the following description of the figures. It show in exemplary embodiment

• 2 a plan view of an exemplary first foam component according to the invention,
• 3 a schematic diagram of an exemplary ventilation lamella according to the invention,
• 4a a schematic diagram of a sectional view of an exemplary ventilation lamella according to the invention through the section line AA,
• 4b a schematic diagram of a sectional view of an exemplary ventilation lamella according to the invention through the section line BB,
• 5 a first embodiment of a manufacturing method according to the invention and
• 6 a second embodiment of a manufacturing method according to the invention.

In the different figures, the same parts are always provided with the same reference numbers, which is why they are usually only described once. In particular, the figures are to be understood to the effect that various components are hidden or shown in simplified form for better clarity. Combined separation injection molding tools typically have a stationary and a mobile tool half. The assignment of the punching devices, the injection devices and/or the cutting devices, for example, is expressly not limited to one of the two tool halves, but can be done as desired.

1a shows the motor vehicle interior 200, which is designed with corresponding molded parts and has a ventilation unit 210 with a register, which blows an air flow into the motor vehicle interior 200. An arrangement of ventilation louvers 100 in the register of the ventilation unit 210 divides the air flow, with the orientation of rotatably mounted ventilation louvers 100 correspondingly deflecting or redirecting the air flow depending on the specifications of the vehicle occupant.

1b shows an enlarged section 1 . A ventilation unit 210 usually has a large number of ventilation slats 100 which are arranged both vertically and horizontally in the air duct 220 . Typically, both a row of rear ventilation slats 100 aligned parallel to one another, ie facing away from motor vehicle interior 200, and a row of front ventilation slats oriented parallel to one another, ie facing towards motor vehicle interior 200, are provided. The front louvers (not shown) may be oriented vertically, while the rear louvers 100 (one shown by way of example) may be oriented horizontally. A correspondingly reversed orientation is also conceivable. While the front ventilation slats must have an optically and tactilely appealing impression for the vehicle occupant, the rear ventilation slats 100, which are optically and tactilely almost completely shielded from the vehicle occupant, can be optimized with regard to their ability to absorb sound. These can therefore have a porous surface or sink marks, dents or indentations that break the air flow and absorb the sound.

1c 12 shows a single prior art louver 100 having a first foam component 110 and a second component 120. FIG. The first foam component 110 is designed as a foam seal. In the prior art, the first foam component 110 and the second component 120 are joined together mechanically and/or manually. While the first foam component 110 is designed with a porous structure/surface for sound absorption, the second component 120 is designed as a stable carrier. A fastening device for fastening with the ventilation unit 210 in the air duct 220 (see 1b ) is designed as a pivoting device 101 so that the orientation of the ventilation lamella 100 in the air duct 220 can be changed. The air flow hits the border 112 of the first foam component 110, which is why the design with sound-absorbing properties for reducing the noise emissions from the ventilation of the motor vehicle interior 200 is crucial here.

2 shows the first foam component 110, which takes over the sound-damping tasks for the rear ventilation lamella 100. It is delimited by an outer border 112, which according to the invention is cut out with the cutting device 307 of the combined separating injection molding tool 300 (cf. 5 and 6 ) is trained. Furthermore, a recess 111 is provided, which is formed with the aid of a punching device 305 and, in principle, also exists for a short time during the core-back method when the tool is closed. In addition, in the first foam component 110 there are connecting holes 113 for engagement with the second component 120 (cf. 3 , 4a ) intended.

3 shows the finished rear ventilation lamella 100 with the first foam component 110, which forms a connecting section 114 with the second component 120. The recess 111 in the first foam component 110 is completely filled by the second component 120 in the illustrated embodiment, with a regional recess in the second component 120 also being conceivable in principle.

4a FIG. 12 shows a sectional view of the connection section 114 along the section line AA 3 in the area of a connecting hole 113 of the first foam component 110. When the second component 120 is injected, it forms a rear fuel behind the first foam component 110 tongue 121. This creates a non-detachable connection between the first foam component 110 and the second component 120. 4b FIG. 12 additionally shows a sectional representation of the connecting section 114 along the section line BB 3 , the back injection molding 121 affecting a much smaller area in the connecting section 114 .

5 shows an embodiment of the manufacturing method according to the invention. In this case, a rear ventilation lamella 100 is formed in a first molding step 301 and a second molding step 302 using a combined separating injection molding tool 300 which has a first tool half 303 and a second tool half 304 . In the first molding step 301, two different injection-mouldable materials are injected into a cavity 306 between the mold halves 303, 304 in an injection molding process, without opening the two mold halves 303, 304 between the injection processes. The injection-moldable material 122 for the second component 120 is first injected into the cavity, which material hardens completely or partially. Then, while the two mold halves 303, 304 remain closed, a slide is opened, typically slowly, so that the cavity 306 enlarges and the foam material 115 for the first foam component 110 is injected into this additional cavity, possibly together with a chemical foaming agent can. In this case, the second component 120 can be back-injected. The residual heat from the second component 120, which has not yet cooled, causes the two components 110, 120 to be firmly joined together. When the two tool halves 303, 304 are opened, the first foam component 110 expands under the influence of the chemical foaming agent and thus an intermediate product 130 is available after the first shaping step 301. The intermediate product 130 can be moved from a first position to a second position within the combined cut-off injection molding tool 300, for example by a robotic arm. In this second position, the two tool halves 303, 304 close again and a cutting device 307 separates a region from the first foam component 110 along an outer border 112. This exposes the pore structure in the interior of the first foam component 110 at the cut surface of the first foam component 110, which pore structure was created during foaming, possibly with the aid of the chemical foaming agent. When the two tool halves 303, 304 are opened, the finished ventilation lamella 100 can be removed.

6 shows another embodiment of the manufacturing method according to the invention. Here too, a rear ventilation lamella 100 is formed in a first molding step 301 and a second molding step 302 using a combined separating injection molding tool 300 which has a first tool half 303 and a second tool half 304 . A significant difference to the embodiment according to 5 is that the second component 120 is injected into a cavity 306 between the tool halves 303, 304 in the second molding step 302. The first foam component 110 is also inserted between the two tool halves 303, 304 as a flat, ready-foamed foam material 115, preferably as a foam roll 125 or web material. The foam material 115 of the foam roll 125 consists, for example, of polyurethane having a pore structure and is, for example, pre-foamed at a different production site and cut to form a foam roll 125 . When the mold halves 303 , 304 are closed, a recess 111 is formed in the foam material 115 in a first shaping step 301 by a punching device 305 . When the two tool halves 303, 304 are opened, an intermediate product 130 is available after the first shaping step 301. The intermediate product 130 can be moved from a first position to a second position within the combined cut-off injection molding tool 300, for example by a robotic arm, but can also remain stationary. In this second position, the two mold halves 303, 304 close again in a second molding step 302 and while a cutting device 307 separates an area from the first foam component 110 along an outer edge 112, in this second molding step 302 the second component 120 is formed by injecting a second injection-moldable material 122 into the cavity 306. While with a cutting device 307 the area outside a border 112 typically results as waste product, with a punching device 305 the area inside the punched recess 111 typically results as waste product. This creates a firm connection between the first foam component 110 and the second component 120, with the formation of an injection molding 121. The foam material 115 of the first foam component 110 can act as a sealing material between the two tool halves 303, 304 during the injection process, while it is simultaneously being cut through the cutting device 307 is held in position. As a result of the cutting process, in addition to the sink marks on the surface of the first foam component 110, the pore structure inside the first foam component 110 can be exposed on the cut surface of the first foam component 110. has arisen. With the opening of the two factory The finished rear ventilation lamella 100 can be removed from tool halves 303, 304.

Reference List

100

rear ventilation slat

101

pivoting device

110

first foam component

111

recess

112

border

113

connection holes

114

connection section

115

foam material

120

second component

121

back injection

122

injection moldable material

125

foam roller

130

intermediate

200

automobile interior

210

ventilation unit

220

air duct

300

Separation injection molding tool

301

first shaping step

302

second forming step

303

first tool half

304

second tool half

305

punching device

306

cavity

307

cutting device

Claims (7)

Method for producing a rear ventilation lamella (100) of a ventilation unit (210) with front and rear ventilation lamellas (100) for a ventilation register of a motor vehicle, using a combined separation injection molding tool (300) with a first tool half (303) and a second Die half (304) comprising the steps of: - Inserting a first component (110) as a flat, foamed foam material (115) between the two mold halves (303, 304), - Closing the two tool halves (303, 304) and punching out a recess (111) in the foam material (115) in a first molding step (301), an intermediate product (130) being produced, - moving the intermediate product (130) from a first position to a second position within the combination cut-off injection molding tool (300), or holding the intermediate product (130) stationary in its position within the combination cut-off injection molding tool (300) - Closing or keeping closed the two tool halves (303, 304) in a second forming step (302), - injecting a second injection moldable material (122) to form a second component (120) while a cutting device (307) of the combined cut-off injection molding tool (300) along an outer border (112) an area of the first foam component (110) separating to expose a pore structure inside the first foam component (110), and - Remove the rear ventilation blade (100) from the detachable injection molding tool (300). procedure after claim 1 , characterized in that the first forming step (301) as a first separation process for forming the recess (111) by punching with a punching device (305), which is part of a first tool half (303) and / or a second tool half (304) of the separation Injection molding tool (300) is carried out. procedure after claim 1 or 2 , characterized in that the injection moldable material (122) is injected into the recess (111) and the foam material (115) is separated from the first foam component (110) in the second molding step (302), in particular at the same time. Method according to one of the preceding claims, characterized in that in the second shaping step (302) in a second separation process the first foam component (110) is cut out with the cutting device (307) along the outer border (112) and in doing so with the cutting device (307) in Position is held while the injection moldable material (122) for the second component (120) is injected into a cavity (306) between the first mold half (303) and the second mold half (304). Method according to one of the preceding claims, characterized in that the first foam component (110) has a higher deformation temperature or softening temperature than the melting temperature of the second component (120). Method according to one of the preceding claims, characterized in that the first foam component (110) open-pored and / or with sink marks for sound absorption, by means a chemical foaming agent. Method for producing a rear ventilation lamella (100) of a ventilation unit (210) with front and rear ventilation lamellas (100) for a ventilation register of a motor vehicle, using a combined separation injection molding tool (300) with a first tool half (303) and a second Die half (304) comprising the steps of: - Injecting two different injection-mouldable materials into a cavity between the two mold halves (303,304), with first injection-mouldable material (122) for a second component (120) being injected, which at least partially hardens, with foam material (115) then for a first foam component ( 110) is injected into an additional cavity formed by enlarging the cavity (306), and the two components (110, 120) are joined together, - Opening of the two tool halves (303,304) and expansion of the first foam component (110) under the influence of a chemical foaming agent, with an intermediate product (130) being produced after this first shaping step, - moving the intermediate product (130) from a first position to a second position within the combined cut-off injection molding tool (300), - Closing the two tool halves (303,304), with a cutting device (307) of the combined separation injection molding tool (300) along an outer border (112) cutting a region of the first foam component (110) to expose a pore structure inside the first foam component (110) separates, and - Open the two tool halves (303,304) and remove the rear ventilation lamella (100) from the separating injection molding tool (300).

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