WO2002027166A1

WO2002027166A1 - Reduced-noise device

Info

Publication number: WO2002027166A1
Application number: PCT/EP2001/011051
Authority: WO
Inventors: Werner Wilhelm Kraft; Karl Heinz Homberg; Dirk Jansen
Original assignee: Basf Aktiengesellschaft
Priority date: 2000-09-29
Filing date: 2001-09-25
Publication date: 2002-04-04
Also published as: AU2001293840A1; US20020040827A1; DE10048755C1

Abstract

The invention relates to reduced-noise devices or the components thereof, particularly engine units or combustion units and the components thereof or fluid circulatory systems and components thereof which are partially or completely composed of thermoplastic synthetic material and which are provided with at least one perforated plate arranged at a distance from the surfaces of the devices, said perforated plate being rigidly fixed and disposed in a substantially positive fit on continuously revolving projections of the thermoplastic component, enveloping the devices either partially or fully.

Description

Noise-reduced devices

description

The present invention relates to noise-reduced devices or their components, in particular noise-reduced engine or combustion units and their components, as well as noise-reduced fluid transmission systems which are partially or completely constructed from thermoplastic materials.

Internal combustion engines make a significant contribution to noise pollution in road traffic. The disturbing engine noise is mainly due to individual sources such as the exhaust outlet, the exhaust wall, the intake system, the combustion process itself, the piston tilting, the injection pump, the fan and the alternator. The structure-borne noise as well as the airborne sound radiation are responsible for the resulting noise level. The engine block, in particular, is a strong structure-borne sound source. For this reason and due to the large number of individual sound sources, reducing the sound radiation on the engine block is particularly difficult. On the one hand, noise-reducing measures aim at optimizing the acoustic behavior of the various individual sources (primary Noise protection), on the other to the so-called secondary noise protection measures, such as the tight encapsulation of e.g. Internal combustion engines (see also Taschenbuch der Technische Akustik, ed. M Heckl and H.A. Müller, 2nd edition, Springer Verlag, Berlin, 1994). For example,

Reduction of engine noise in all motor vehicles with internal combustion engines Intake and exhaust silencers installed and engines and gears suspended elastically. In diesel engines, a significant reduction in noise level can only be achieved by additional encapsulation of the engine and transmission. Such capsules often have an inside

Sound absorption material. Disadvantages of the encapsulation are that additional material is inevitably required and that at least one further operation is required in the production process, which regularly has a negative impact on weight and costs.

DE 297 12 278 U1 describes an underbody cladding made of a thermoplastic material with a sealing lip which is also molded on. A bowl-shaped

• Underbody cladding can be stiffened by webs in the cavity area facing the engine. On these bridges a thin membrane in the form of an oscillating film can be applied for the sake of damping engine noise. In this way, the engine noise is only partially absorbed or reduced, especially only towards the outside, and not at the same time towards the interior. Rather, if the film is not optimally flexible, ie if the vibration behavior is not optimally matched to the engine noise, the engine noise may be reflected and thereby increase the noise level in the interior. In order to cover the entire frequency spectrum of a motor to some extent effectively, a large number of differently sized membrane foils formed by webs and membrane foil would be required. The more ribs that are used as the underbody protection cavity for ribbing, the heavier this component becomes. The aim of motor vehicle construction is, however, to minimize the vehicle weight in order to be able to reduce fuel consumption.

DE-A 44 04 502 discloses a sound-absorbing cover, in particular a cylinder head cover for internal combustion engines. The noise source is encased by a surface which is closed to the outside and has cavities on the inside formed by crossing stiffening ribs. A particularly good noise reduction is achieved if the cavities are sealed with a closed film, so that a large number of closed hollow chambers is obtained. In addition, in a less advantageous embodiment, the film covering the hollow chamber can also be provided with a hole.

For the sake of weight loss in particular, there will be many

Internal combustion engines ^' have been equipped with suction modules made of thermoplastic materials for some time (e.g. in the Mercedes 2, 8L and 3, 2L inline six-cylinder engine from Daimler-Benz (1992) or in the 2, four-cylinder direct injection diesel engine from BMW (1999)) , Compared to conventional systems made of metal - usually aluminum is used in such suction systems - these plastic suction modules have a further advantage of a better ecological balance, i.e. they are more environmentally friendly to manufacture and recycle, require less material due to lower component thicknesses and are overall simpler and cheaper to manufacture. However, the noise insulation properties of components made of thermoplastics are disadvantageous due to their lower density compared to components made of metal. This can be done without immediately having to encapsulate

Often improve the noise behavior of plastic suction systems by placing them on the outer surface Suction modules one or more webs firmly attached. However, such ribbing of components has natural limits, for example for design reasons. In addition, ribbing does not always provide the desired result, so that only one aluminum component would come into question again for reasons of noise reduction while accepting the disadvantages mentioned above.

In the case of conduit systems for liquids or gases, considerable noise pollution is regularly due to flow noises. To reduce noise, one often makes use of coherently covering the entire transmission system with a metal sheet and filling the resulting intermediate layer with insulating material. However, these measures are labor-intensive and costly in terms of materials and costs.

The present invention was therefore based on the object for e.g. to be able to use any noise-intensive engine or combustion unit on structural components made of thermoplastic plastics in order to achieve sustainable noise reduction with them and to no longer be dependent on metal, in particular aluminum components.

Accordingly, noise-reduced devices and their components, in particular noise-reduced engine or combustion units and their components, have been found which are partially or completely constructed from thermoplastic materials and have at least one perforated plate at a distance from the engine or combustion units or components, in particular from thermoplastic materials, which are fixed connected and rests essentially in a form-fitting manner on continuously rotating attachments of the thermoplastic component and partially or completely encases the engine or combustion unit.

Furthermore, noise-reduced fluid transmission systems have been found which are partially or completely constructed from ^' thermoplastic materials and which, at a distance from the fluid transmission system made of, in particular, thermoplastic materials, have at least one perforated plate which is firmly connected and essentially lies in a form-fitting manner on continuously rotating attachments of the thermoplastic component and the fluid transmission system components Split or fully encased. One aspect of the present invention is a noise reduction device having an outer housing and an inner mechanism. When the device is operating, vibrations are transmitted through the housing to an outer surface of the housing. These vibrations are perceived as audible noise. The noise-reduced device has at least one web of a predetermined height. The land has an upper edge and a lower edge that mates with and is attached to the outer surface of the device. The noise reduction structure also includes at least one plate with multiple perforations and a lower surface attached to the top edge of the land. The ridge holds the plate a predetermined distance from the lower conformable edge, thereby forming at least part of a chamber. The plate is substantially sealed to the web and the housing around the periphery of the plate and encloses part of the outer surface of the housing. iii

Another aspect of the present invention is

Housing structure of a noise-reduced device for externally attenuating noise generated in the housing and transmitted to the outer surface of the housing as a perceptible audible sound. The housing structure comprises a housing with an outer surface, at least one web extending outward from the housing outer surface and ending at an upper edge. The land also has a lower edge that mates with the housing and is attached to the outer surface. At least one plate has multiple perforations and a lower surface attached to the upper edge of the web. The web holds the plate at a predefined height from the outer surface of the housing. The plate, the outer surface of the housing and the web form a chamber.

In a preferred embodiment, the

Noise reduction structure or the housing structure a plurality of webs and a plurality of plates, these webs and plates being arranged next to one another and in this way defining a plurality of adjacent chamber parts. The chamber parts defined by the webs can have a polygonal wall configuration.

Suction pipes, suction modules, air filters, cylinder head covers, alternators or fans can be considered as noise-reduced engine or combustion units and their components, which are partially or completely constructed from thermoplastic materials. Motor and combustion units within the meaning of the invention also include, for example, transmission systems and electric motors and hybrid drives, to the extent these are equipped with components made of thermoplastic materials.

Among the suction tubes, for example, those with a resonance circuit, a vibrating tube circuit or a channel shutdown are suitable. Suction modules made of thermoplastic materials are usually more complex and can e.g. include the cylinder head cover with the integrated or connected components, the connection elbow for the swirl ducts, the lower part of the air filter housing, the hot-film air mass meter, the oil separation system for the blow-by gases, including pressure valve, and the air filter cover and, if necessary, a cover.

The geräuschabstrahlenden devices, the "noise level is reduced, sat partially or completely made of thermoplastic materials together. In principle, all types of plastic and mixtures come this class of polymers contemplated. Suitable examples are polyesters such as polybutylene terephthalate (PBT), for example the commercial product Ultradur ^®, and polyethylene terephthalate ( PET), polyamides such as polyamide 6 or polyamide 66, for example available under the Ultramid ^® brand, polyether sulfones such as the commercial product Ultrason ^® E, polysulfones such as the commercial product Ultrason ^® S, polyoxymethylenes, for example the commercial product Ultraform ^® , polyetherimides, polyether ketones, polyphenylene sulfides, polyphenylene ethers (PPE), PPE / HIPS blends (HIPS = High Impact Polystyrene) such as the commercial product Luranyl ^® , styrene (co) polymers such as ASA, ABS and SAN polymers (also available under the trademarks Luran ^® S, Terluran ^® / Ronfalin ^® or Luran), polymethyl methacrylates such as Lucryl ^® , Polyketones, syndiotactic polystyrene, MABS polymers such as the commercial product Terlu or polycarbonates (PC) and their mixtures (all of the aforementioned commercial products: BASF AG). PBT / ASA, ASA / PC and PBT / PC blends are examples of mixtures. The thermoplastics mentioned can also be used fiber-reinforced, for example with glass, carbon or aramid fibers. Rubber-modified thermoplastics are also suitable. For applications as a component of internal combustion engines, it is advisable to select materials that can be thermally and mechanically permanently loaded. For suction pipes and suction modules, preference is given to using polyamides, in particular polyamide 6 and polyamide 66, which are preferably fiber-reinforced.

The thermoplastics in question and their mixtures and their preparation are known to the person skilled in the art and are generally commercially available products. Suitable ones Fiber-reinforced polyamides are commercially available, for example, under the trademarks Ultramid ^® B3WG7 and Ultra id ^® A3HG7.

According to the invention, at least one perforated plate is attached at a distance from the surfaces of the components made of thermoplastic materials, said perforated plate being firmly connected and resting essentially in a form-fitting manner on continuously rotating attachments of the thermoplastic component and partially or completely encasing the engine or combustion unit or component. The perforated plates can e.g. be made from the aforementioned thermoplastic materials or their mixtures, also in fiber-reinforced form. The perforated plate is often made of the same material as the thermoplastic component. There are also perforated plates made of other plastics, e.g. made of polypropylene, polyethylene or their

Copolymers, of polystyrene, of thermosetting plastics such as polyurethanes or also of metallic materials, e.g. made of iron, steel or aluminum. The perforated plates generally form a defined volume with the side walls lying on the outside of the thermoplastic component. The side walls represent continuous circumferential attachments and advantageously form-fit both with the surface on which they are attached or rest and with the perforated plate lying thereon, so that no openings remain at these connecting seams or joints. The perforated plates are firmly connected to the side walls. This connection can be done by gluing, welding, e.g. Vibration welding, or screwing are made. Furthermore, so-called clip closures or snap fastenings are possible, as they are already available for

Attachment of components to the engine block can be used. An adhesive connection can e.g. can be produced with silicone adhesives known to the person skilled in the art and commercially available.

In a preferred embodiment, an elastic intermediate layer is applied between the surface of the components and the side walls of the perforated plates. Suitable interlayer materials are, for example, natural or synthetic rubber, thermoplastic elastomers such as styrene copolymers, for example so-called SBS or SEBS types (Kraton ^® D or Kraton ^® G, Shell), or elastomer alloys, for example made of EPDM and polypropylene, or thermosets such as polyurethane foams.

This elastic intermediate layer, on which the side walls stand or rest, can also extend beyond the support areas of the component surface, ie the surface of the Cover the reduced-noise device or components thereof in whole or in part.

In addition, the perforated plate walls may have holes, notches or omissions in the support area for the purpose of attachment, e.g. in a rail mounted perpendicular to the wall, into which elevations, for example in the form of bolts, can be inserted on the surface of the device. Are these surveys e.g. also made of a thermoplastic, you can are melted by means of a heater, ultrasound or laser light. By allowing the melt to spread over the edge areas of the holes, notches or openings, an intimate connection between the perforated plate and the surface of the noise-reduced device is obtained after cooling, especially when the edge area of the holes, notches or openings also softens or is melted and mixed with the melt of the elevation. The edge area can be heated specifically or soften or melt through contact with the melt of the elevation. Those skilled in the art are such

Connection types known as heat, ultrasound or laser connections.

In a preferred embodiment, perforated openings are provided exclusively in the perforated plate itself. The total perforated area of a perforated plate preferably assumes a value in the range from 0.5 to 40%, preferably 3 to 30%, based on the area of the perforated plate. Considerable noise reductions with a total perforated area of around 20% are already achieved on a regular basis. The thickness of the perforated plate can vary widely and also depends, among other things, on the size of the perforated plate itself, the perforated plate material, the size of the sound-emitting device or the radiated sound intensity. It is usually in the range from 0.3 to 6, preferably in the range from 1 to 4 mm. The shape of the holes in the perforated plate can be any, ie regular or irregular. The diameter or the side length of the holes are usually in the range from 0.3 to 10 mm, preferably from 0.8 to 6 mm. A plurality of holes are preferably made regularly or in a random distribution on a perforated plate or a perforated plate segment. A perforated plate usually has at least three holes. The holes in the perforated plate can be obtained by known methods, for example by means of punching or drilling. The perforated plate can also be produced in one production step, for example by means of injection molding. The area that can be covered by the perforated plate depends on the one hand on the structural conditions of the sound source, and on the other hand on the fact that in certain cases a complete covering no longer has any significant advantages over the covering of a selected surface. The distance between the perforated plate and the underlying device is determined, inter alia, by the height of the side walls on which the perforated plate rests, the shape of the perforated plate and the shape of the underlying device. The distance from components of engine and combustion units for conventional components such as intake manifolds or intake modules is generally in the range from 1 to 50 mm, preferably from 3 to 25 mm.

The perforated plate attached or attached to the side walls can encase the entire noise source or only a part of it. Furthermore, it is possible to arrange a plurality of perforated plate segments connected to one another or unconnected on the device producing the noise, so that either the entire noise source or only part of it is encased. In this way, the sheathing can be adapted to technical design requirements.

In a further embodiment, the peripheral side walls are also partially or completely provided with holes, as previously described for the perforated plate.

In a preferred embodiment, one or more webs are applied to the outer surfaces of the component components made of thermoplastic materials. These webs can be arranged in any way on the thermoplastic component component, as long as they are positively connected to the component surface. Several webs can run parallel or almost parallel, but can also cross each other and in this way, for example, form a multitude of geometric patterns. For example, only square, rectangular, triangular or trapezoidal segments can be attached to the surface and form a regular or any pattern. Furthermore, these geometric figures can also be combined with one another as desired. This ribbing serves to stiffen the component and has the purpose, in particular, of suppressing the formation of structure-borne noise, especially in those places which are found to be sound-intensive. The webs are usually composed of the above-mentioned thermoplastic materials themselves. They are preferably made of the same material as the plastic component on which they are attached. The webs or ribs can be glued or welded onto the thermoplastic surface using conventional methods, for example Vibration welding, to be positively attached. Advantageously, the housing and the webs, in particular in the case of injection molded components, are also produced directly in the manufacturing process by a suitable design of the injection molding tool. In cross section, the webs can be, for example, arched, that is to say in the form of a bead, triangular, square or rectangular. For reasons of simple manufacture, the webs generally have a more or less uniform height. In the case of suction pipes or modules, this is generally in the range from 1 to 50, preferably from 3 to 40 mm.

The height of the webs or ribs, insofar as they are also encased by the perforated plate, is limited by the distance between the perforated plate and the underlying component surface. In one embodiment, the perforated plate rests on the upper edges of individual or all of the webs. The overlying perforated plate can also be completely or partially glued, welded or otherwise to the webs on which it rests, e.g. with the help of screws or clips. In this case, the perforated plates form perforated plate segments, which themselves have a closed volume. The webs can only be covered by the perforated plate sheathing or can be arranged completely outside the surface sheathed by the perforated plate or can be located both below and next to the sheathing.

Furthermore, it was found that also at

Fluid transmission systems, for example pipelines for the passage of gases and liquids, can reduce the noise level in a sustainable manner by, in particular, completely or partially replacing systems that are partially or completely constructed from thermoplastic materials with at least one perforated plate, as previously described jacketed. The perforated plate can cover, for example, only a certain sub-segment of a tube or can encase the entire circumference of the tube. Furthermore, apply to this embodiment ^'the previously made general and specific information accordingly.

Furthermore, the noise-reduced devices can be located in the space between the perforated plate and the underlying noise-emitting surface, i.e. in the chamber part, sound absorbing or noise reducing materials, e.g. contain porous sound absorbers such as fibers or open-cell foams. Felt, glass or mineral fiber, organic find suitable absorbers

Fibers such as wood pulp and coconut fibers, and open-cell foams, preferably made of polyurethane, use. Usually will Glass and / or mineral fibers with fiber diameters in the range from 2 to 20 μm are used. At the crossing points, the fibers are generally connected to one another by plastic resins, for example phenolic resins.

The noise-reduced engine and combustion units and their components, as well as the noise-reduced fluid feed-through systems, can, among other things. Used in passenger cars or trucks, e.g. here for the alternator housing, for the housing for the gearbox or the injection pump, for marine drives, household and electrical appliances, tools or burners.

The devices according to the invention are characterized in that they bring about a considerable reduction in noise and make it possible to dispense with noise reduction measures such as encapsulation. They are easy to manufacture and assemble and can be easily and effectively adapted to the noise problem to be solved in each case. For example, it is possible, even with initially noisy plastic suction modules

To reduce the noise level so effectively that it is no longer necessary to switch to aluminum suction modules.

The above description is considered a description of only the preferred embodiment. Modifications of the invention will occur to those skilled in the art and to those who utilize the invention. It is therefore understood that the embodiment shown in the drawings and described above is only for illustration and is not intended to limit the scope of the invention.

The present invention is explained in more detail with the aid of illustrations and examples.

Figure 1 is a perspective view of a

Plastic suction module (1), which partially shows a perforated plate (3) which is attached to a rib structure (2) formed by a plurality of outer, intersecting webs.

Figure 2 shows a cross-section along the section plane A. Examples:

A suction module made of polyamide 6 (Ultramid® B3WG7) was sounded through a loudspeaker with white noise from the inside. The noise level measurements were carried out using the B&K 2260 sound intensity measurement system from Brüel & Kjäer. The suction module for the comparison measurement (suction module V) had a ribbing as indicated in Figure 1, the suction module according to the invention (suction module 1) was also equipped with a perforated plate which at least adhered to the webs serving as side walls, on which the perforated plate rested was.

Suction module 1: 50.17 dB (A)

Suction module V: 55.22 dB (A)

Claims

claims

1. Noise-reduced devices or their components, which are partially or completely constructed from thermoplastic materials, characterized in that they have at least one perforated plate spaced apart from the surfaces of the device, which is firmly connected and rests essentially in a form-fitting manner on continuously rotating attachments of the thermoplastic component and partially or completely encased the device.

2. Noise-reduced devices or their components according to claim 1, characterized in that these engine or combustion units and their components, which are partially or completely constructed from thermoplastic materials and have at least one perforated plate spaced from the surfaces of the engine or combustion units or components , which are firmly connected and essentially form-fitting on continuously rotating attachments of the thermoplastic component and represent the engine or combustion unit in parts or fully encased.

3. Noise-reduced devices or their components according to claims 1 or 2, characterized in that they represent a suction pipe, a suction module, an alternator housing, a housing for gearboxes, injection pumps or ship drives, or household appliances, electrical appliances, tools or burners.

4. Noise-reduced devices or their components according to claim 1, characterized in that these fluid transmission systems and their components, which are partially or completely constructed from thermoplastic materials and spaced from the surface of the fluid transmission system, have at least one perforated plate which is firmly connected and essentially positive consistently revolving attachments of the thermoplastic component and the

Represent fluid delivery systems in parts or fully encased.

5. Noise-reduced devices or their components according to claims 1 to 4, characterized in that below and / or in addition to the casing through the perforated plate, one or more webs on the surface of the device or the component is applied and positively connected to it.

6. Noise-reduced devices or their components according to claim 5, characterized in that a plurality of webs run parallel or almost parallel or form a rib structure.

7. Noise-reduced devices or their components according to claims 1 to 6, characterized in that as thermoplastic plastics polyesters, polyamides, polyether sulfones, polysulfones, polyoxymethylenes, polyetherimides, polyether ketones, polyketones, polyphenylene sulfides, polyphenylene ethers, polyphenylene ethers / HIPS-Blendε, syndiotactic polystyrene, Styrene (co) polymers, polymethyl methacrylates, MABS polymers, polycarbonates or mixtures thereof can be used.

8. Noise-reduced devices or their components according to claims 1 to 7, characterized in that the holes in the perforated plate are circular, oval, square, rectangular or trapezoidal.