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Title:
METHOD AND MACHINE FOR PRODUCING AN INSERT STRUCTURED TO ACOUSTICALLY AND THERMALLY INSULATE COMPONENT PARTS OF A VEHICLE
Document Type and Number:
WIPO Patent Application WO/2016/020851
Kind Code:
A1
Abstract:
A method for producing a sound-deadening and/or thermally insulating insert (1) that can be installed in a vehicle; the method comprises the steps of providing a forming casing (5) having at least one outer perforated wall (8) and comprising an inner seat (7) shaped according to the shape of the insert (1) to be produced; providing, on the outside of said forming casing (5), punching needles (13) structured to pass through a skein of fibres; arranging a given amount of fibres (F) inside the seat (7); making said punching needles (13) penetrate into the casing (5) through said perforated wall (8) to cause localized displacements on the fibres (F) inside the seat (7) in order to interweave/twist the fibres (F) together and join/compact them.

Inventors:
ZARA, Luigi (Via Crevada 50, Refrontolo, I-31020, IT)
Application Number:
IB2015/055938
Publication Date:
February 11, 2016
Filing Date:
August 05, 2015
Export Citation:
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Assignee:
SO.LA.IS. - SOCIETA' LAVORAZIONE ISOLANTI - S.R.L. CON UNICO SOCIO (Via Crevada 69, Refrontolo, I-31020, IT)
International Classes:
D04H3/004; D04H1/46; D04H1/76; D04H3/07; D04H18/02; D04H18/04; F01N1/04; F01N3/28
Domestic Patent References:
2005-06-30
1999-05-14
2005-06-30
Foreign References:
GB676681A1952-07-30
US20090101052A12009-04-23
US20110062626A12011-03-17
DE102012108168A12014-04-03
JP2008202201A2008-09-04
US20090272600A12009-11-05
EP1861592A12007-12-05
EP2602370A12013-06-12
Attorney, Agent or Firm:
ZAMPROGNO, Bruno et al. (Via Viotti 9, Torino, I-10121, IT)
Download PDF:
Claims:
CLAIMS

1. A method for producing an insert (1) structured to acoustically and/or thermally insulate component parts of a vehicle provided with an internal combustion engine; said method being characterized in that it comprises the steps of: providing a forming casing (5) having an inner seat (7) shaped according to the shape of the insert (1) to be produced delimited by at least one perforated wall (8) provided with through holes (11) communicating with said seat (7); providing, on the outside of said forming casing (5), penetrating means (10) structured to penetrate into said seat (7) of said forming casing (5) through said openings (11) ; placing a given amount of fibres (F) inside the seat (7) of said casing (5); making said penetrating means (10) penetrate into the seat (7) of the casing (5) exclusively through said openings (11) in said perforated wall (8) to cause displacements on the fibres (F) confined inside the seat (7) in order to interweave/twist the fibres (F) together and join/compact them; said forming casing (5) being made of a rigid material that cannot be penetrated/crossed by said penetrating means (10) .

2. A method according to claim 1, wherein said penetrating means (10) comprise punching needles (13) supported by a needle-holder head (12); said method comprising the step of moving said needle-holder head (12) and/or said forming casing (5) with respect to each other along a first direction (A) parallel to said punching needles (13), according to a rectilinear reciprocating motion (A1,A2), so that said punching needles (13) penetrate into said seat (7) in said forming casing (5) exclusively through said openings (11) .

3. A method according to claim 2, comprising the step of moving said needle-holder head (12) and/or said forming casing (5) along at least a second direction (B) substantially orthogonal to said first direction (A) so as to vary the penetration points of the punching needles (13) in said seat (7) through said openings (11) .

4. A method according to claim 3, wherein the displacement of said needle-holder head (12) and/or of said forming casing (5) along at least said second direction (B) may be comprised between approximately 1 mm and 12 mm.

5. A method according to claims 1 and 2, wherein said forming casing (5) comprises two opposite perforated walls (5) that delimit said seat (7) and in which the corresponding through holes (11) are axially aligned with one another, said method comprising the step of moving said needle-holder head (12) in such a way that the punching needles (13) extend inside the forming casing (5) so as to pass through both of the perforated walls (8) so that the respective points protrude from said perforated walls (8) .

6. A method according to claim 1, comprising the step of performing a suction through said openings (11) in at least one said perforated wall (8) of said forming casing (5) to suck the fibres into said seat (7) .

7. A method according to claim 1, wherein the fibres are continuous.

8. A method according to claim 1, wherein the fibres are wound around at least one axis so as to form a wound coil .

9. A method according to claim 1, wherein the fibres are voluminized and/or texturized.

10. A method according to claim 1, wherein the fibres comprise basalt fibres, and/or silica fibres, and/or fibres containing polystyrene and/or polypropylene and/or polyamide and/or Kevlar and/or carbon and/or aramid and/or cotton and/or fibres of metal material.

11. A method according to claim 1, wherein said forming casing (5) is made of a metal material.

12. A method according to claim 1, wherein said openings (11) have a width or a diameter comprised between approximately 6 mm and 12 mm.

13. A method according to claims 1 and 2, wherein said openings (11) comprise through holes, each of which is associated with a corresponding punching needle (13) .

14. A method according to claim 1, wherein said penetrating means (10) comprise one or more nozzles (42) for emitting jets of pressurized air and/or water, said method comprising the step of emitting one or more jets of pressurized air and/or water by means of said nozzles (42) into the seat (7) of said forming casing (5) through said through holes (11) .

15. A method according to claim 1, wherein said casing (5) comprises a frame (6) and at least one perforated wall (8) hinged to the frame (6) so as to be able to rotate about an axis (C) between an open position and a closed position of said seat (7) .

16. A machine (20) (35) (40) for producing an insert (1) structured to acoustically and/or thermally insulate component parts of a vehicle provided with an internal combustion engine; said machine being characterized in that it comprises: a forming casing (5) which has an inner seat (7) shaped according to the shape of the insert (1) to be produced and delimited by at least one perforated wall (8) provided with through holes (11) communicating with said seat (7), supporting means (22) to support said forming casing (5), an interweaving device (9) provided with penetrating means (10) designed to pass through fibres (F) contained in said seat (7) of said forming casing (5) through said openings (11); said interweaving device (9) being designed to actuate said penetrating means (10) to make them penetrate into the casing (5) exclusively through said openings (11) obtained in said perforated wall (8) so as to cause displacements on the fibres (F) confined inside the seat (7) in order to interweave/twist them together and join/compact them; said forming casing (5) being made of a rigid material that cannot be penetrated/crossed by said penetrating means (10).

17. A machine according to claim 16, wherein said penetrating means (10) comprise punching needles (13) and said interweaving device (9) comprises a needle-holder head (12) supporting said needles (13), and first actuating means (24) structured so as to move said needle-holder head (12) and/or said forming casing (5) along a first direction

(A) substantially parallel to said punching needles (13), according to a reciprocating motion (Al, A2 ) so that said punching needles (13) penetrate into said forming casing (5) exclusively through said openings (11) in said perforated wall (8) .

18. A machine according to claim 16 or 17, comprising second actuating means (25) designed, in use, to move said forming casing (5) and/or said needle-holder head (12) with respect to one another, along at least a second direction

(B) substantially orthogonal to said first direction (A) so as to vary the penetration points of the punching needles (13) in said forming casing (5) .

19. A machine according to claim 18, wherein said second actuating means (25) are designed to move said needle-holder head (12) and/or said forming casing (5) along at least a second direction (B) so that the displacement of said needle-holder head (12) is comprised between approximately 1 mm and approximately 12 mm.

20. A machine according to claim 18 or 19, wherein said forming casing (5) comprises two opposite perforated walls (8) that delimit said seat (7) and in which the corresponding openings (11) are axially aligned with one another, said actuating means (25) being designed to move said needle-holder head (12) in such a way that the punching needles (13) extend inside the forming casing (5) so as to pass through both of the perforated walls (8) and protrude with the respective points from said walls (8) .

21. A machine according to claim 16, comprising suction means (27) designed to perform a suction through said openings (11) in at least one said perforated wall (8) of said forming casing (5) to suck the fibres into said seat ( 7 ) .

22. A machine according to claim 16, wherein said forming casing (5) is made of a metal material.

23. A machine according to claim 17, wherein said openings (11) comprise through holes, each of which is associated with a corresponding punching needle (13) .

24. A machine according to claim 16, wherein said interweaving device (9) comprises a head and one or more nozzles (37) (42) for emitting water or air coupled to said nozzle-holder head (36), while said penetrating means comprise the jets of pressurized water or air emitted by said nozzles (37) (42) .

25. A sound-deadening and/or thermally insulating insert (1) structured so as to be installed in a component of a vehicle; the insert (1) being produced by means of the method according to any one of the claims from 1 to 15.

26. An exhaust gas system of an internal combustion engine of a vehicle comprising an insert (1) produced according to claim 25.

Description:
"METHOD AND MACHINE FOR PRODUCING AN INSERT STRUCTURED ACOUSTICALLY AND THERMALLY INSULATE COMPONENT PARTS OF

VEHICLE"

TECHNICAL FIELD

The present invention relates to a method and machine for producing an insert structured to acoustically and/or thermally insulate component parts of a vehicle provided with an internal combustion engine.

In particular, the present invention relates to a method and machine for producing a sound-deadening and/or thermally insulating insert that can be installed in parts/components of an internal combustion engine and/or in an exhaust system of a vehicle such as an automotive vehicle, a motor vehicle or the like, to which the following description specifically refers but without any loss of generality.

BACKGROUND ART

As is known, silencers of the exhaust systems of motor vehicles define a stretch of the exhaust path along which the noise produced by the pressure waves of the exhaust gases emitted by the engine is attenuated. The silencer typically comprises an outer metal containment shell or casing, one or more metal ducts and/or diaphragms arranged within the casing and through which, in use, the exhaust gases flow, and an insert made of a sound-deadening material, typically mineral fibres, which is arranged in the free chambers/cavities of the casing in such a way as to fill the internal space thereof and coat/envelop the ducts and/or diaphragms so as to attenuate the transmission of the noise generated by the gases towards the outside.

A method for producing a sound-deadening insert is described in US patent application 2009 0272 600 Al . Said method essentially consists of the following steps: spinning the components of an inorganic compound with an organic polymer to manufacture an inorganic mixed fibre (silica sol, alum chloride), compressing the mixed fibre to produce a compact preformed mattress, localized needle punching of the preformed compressed mattress on the opposite surfaces using needles spaced apart so as to make tiny loops of fibre protrude from the opposite surfaces of said mattress, and lastly firing, to heat the mattress to a temperature of 1250° so as to create a rigid and compact layer formed of SILICA and alumina. This method involves complex and costly processes such as for instance the compression and firing operations.

Methods are also known in the prior art which basically envisage winding one or more glass fibre threads so as to obtain a skein, and permanently joining the fibres locally. For example a method described in patent application EP 1 861 592 envisages making stitches using thread or emitting a jet of pressurized air to compact the mattress so as to prevent it from opening up when being installed in the silencer.

Another method is described in patent application WO 9 923 367, which envisages voluminizing the glass fibres and joining them by means of polyethylene threads.

These methods have the technical drawback of requiring complex operational steps which have a significant impact on the overall costs necessary for producing the insert.

In order to make the methods described above less complex and thus make the insert less expensive to manufacture, a method described in patent application EP 2 602 370 Al filed by the Applicant essentially comprises the steps of winding a voluminized strip of continuous fibre around a winding axis in such a way as to obtain a tubular skein, placing the skein on a flat surface and needle punching the flat tubular skein along needling lines so as to compact/interweave the continuous fibres locally and without interruption, and obtain segments/stretches of compacted fibres that prevent the mattress from opening up.

Although the method described above is extremely simple, economical and efficient, the Applicant has conducted an in-depth study with the purpose of identifying a solution that would achieve the aim of producing a sound- deadening and/or thermally insulating insert with a machine/method that is even easier and more economical to implement compared to the known methods described above.

W02005/ 059225 describes a method for producing a preform that can be installed in a brake disc and is made of discontinuous fibre material. The method envisages the steps of: preparing a plate made of a soft material that needles cannot penetrate and provided with a series of outwardly open cylindrical seats that internally house discontinuous fibres, using a needle punching device, advancing the plate in a first direction, and operating the needle punching device so that the needles pass through the body of the plate as it advances, and thus penetrate into the discontinuous fibres in the seats.

As the needles pass through the body of the plate tiny particles become detached from the plate. These particles of fabric or cellular foam or neoprene foam or polystyrene foam are deposited inside the seat and/or incorporated into the fibre thus contaminating the insert. The presence of contaminating particles in the insert is unacceptable in that such particles tend to catch fire when exposed to the high temperatures of vehicle exhaust systems, which clearly represents a pollution problem.

Furthermore, owing to the fact that the needles repeatedly pass through the body of the plate, the latter is subject to direct wear and to contamination by the fibres as these are progressively incorporated into said plate. The presence of fibres in the plate clearly makes the latter unsuitable for use to produce inserts that require fibres of a different type from those that have been incorporated, in that portions of the latter could be pushed by the needles into said insert.

DISCLOSURE OF INVENTION

The purpose of the present invention is thus to provide a solution that achieves the aims listed above.

The above purpose is achieved by the present invention in that it relates to a method for producing an insert structured to acoustically and/or thermally insulate component parts of a vehicle provided with an internal combustion engine, said method being characterized in that it comprises the steps of: providing a forming casing made of a metal material that cannot be penetrated by needles, having at least one outer perforated wall provided with through holes and comprising an inner seat shaped according to the shape of the insert to be produced; providing, on the outside of said forming casing, penetrating means structured to penetrate into said seat of said forming casing through said openings in said perforated wall; arranging a given amount of fibres inside the seat in said casing; making said penetrating means penetrate into the casing exclusively through said openings in said perforated wall to cause localized displacements on the fibres inside the seat in order to interweave/twist the fibres together and join/compact them. Preferably, the penetrating means comprise a needle-holder head provided with punching needles; and the method comprises the step of displacing said needle-holder head and/or said forming casing with respect to one another, along a first direction parallel to said punching needles, according to a reciprocating rectilinear motion, so that said punching needles penetrate into said forming casing exclusively through the openings obtained in the perforated wall . Preferably the displacement of the needle-holder head along said first direction is performed in such a way that the punching needles are intermittently withdrawn from and inserted into said forming casing through the openings obtained in the perforated wall. Preferably, the method comprises the step of displacing the needle-holder head and/or the forming casing along at least a second direction substantially orthogonal to said first direction so as to vary the penetration points of the punching needles in said forming casing. Preferably the forming casing comprises two opposite perforated walls which delimit the seat and in which the corresponding openings are axially aligned with one another, while the method comprises the step of displacing the needle-holder head in such a way that the needles extend inside the casing so as to pass through both of the plates and protrude with the respective points from one of said plates. Preferably the penetrating means comprise one or more nozzles for emitting jets of pressurized air and/or water; the method comprises the step of emitting one or more jets of pressurized air and/or water by means of the nozzles into the seat of the forming casing through the openings. Preferably, the method comprises the step of performing a suction through the openings in one said perforated wall of said forming casing to cause the fibres to be sucked into said seat.

The present invention also relates to a machine for producing an insert structured to acoustically and/or thermally insulate component parts of a vehicle provided with an internal combustion engine; the machine comprising supporting means for supporting a forming casing which has at least one perforated wall and comprises an inner seat shaped according to the shape of the insert to be produced, an interweaving device provided with penetrating means designed to pass through a skein of sound-deadening fibres contained in the seat; the interweaving device actuates, in use, the penetrating means to make them penetrate into the seat of the casing through the perforated wall so as to cause localized displacements on the fibres inside the seat in order to interweave/twist them together and join/compact them. Preferably said penetrating means comprise punching needles, and the interweaving device comprises a needle- holder head, first actuating means structured so as to displace said needle-holder head and/or the forming casing along a first direction substantially parallel to the punching needles, according to a reciprocating and intermittent motion so that said punching needles penetrate into said forming casing through the openings obtained in the perforated wall. Preferably the first actuating means are designed, in use, to displace said needle-holder head along said first direction according to a reciprocating motion in which the punching needles are intermittently withdrawn from and inserted into said forming casing through the openings obtained in the perforated wall. Preferably, the machine comprises second actuating means designed, in use, to displace said forming casing and/or said needle-holder head with respect to one another, along at least a second direction substantially orthogonal to said first direction so as to vary the penetration points of the punching needles in said forming casing. Preferably the forming casing comprises two opposite perforated walls which delimit said seat and in which the corresponding through holes are axially aligned with one another; the first actuating means being structured so as to displace, in use, the needle-holder head in such a way that the punching needles extend inside the casing so as to pass through both of the plates and protrude with the respective points from one of said plates. Preferably, the interweaving device comprises a head and one or more nozzles coupled to said nozzle-holder head, while said penetrating means comprise the jets of pressurized water and/or air emitted by said nozzles. Preferably, the machine comprises suction means designed to suck air out through the openings in one said perforated wall of said forming casing to cause the fibres to be sucked into said seat.

The present invention also relates to a sound- deadening and/or thermally insulating insert structured so as to be installed in a component of a vehicle; said insert being produced by means of the method according to the present invention. Preferably, the insert comprises a plurality of fibres and is needle punched over substantially the entire outer surface area of the two largest opposite surfaces. Preferably, the insert comprises at least one through hole designed, in use, to cover a duct of said exhaust system.

Preferably, the insert is shaped to be fitted to a silencer. Preferably, the insert is shaped to be housed in a chamber of a silencer. Preferably, the insert may be shaped to be fitted to at least a shell or monocoque or protection plate of a heat shield so as to thermally and/or acoustically insulate one or more components of the vehicle.

The present invention also relates to a heat shield that can be fitted to a component of a vehicle, wherein the heat shield may comprise an outer containment/protection plate or shell or monocoque that can be connected/coupled to the outer surface of said component in order to cover it, and a sound-deadening and/or thermally insulating insert 1 that is arranged between said plate or monocoque or shell and said outer surface and is produced by means of the method according to the present invention.

The present invention also relates to a silencer of an exhaust gas system of an internal combustion engine of a vehicle comprising a sound-deadening and/or thermally insulating insert made according to the present invention.

The invention also relates to an exhaust gas system of an internal combustion engine of a vehicle comprising a silencer made according to the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will now be described with reference to the accompanying drawings, illustrating a non- limiting embodiment thereof, in which:

- Figure 1 is a schematic plan view, with parts shown on an enlarged scale for the sake of clarity, of a sound- deadening and/or thermally insulating insert made according to the present invention;

- Figure 2 schematically illustrates a portion of an exhaust gas system of an internal combustion engine of a vehicle comprising a silencer provided with the insert shown in Figure 1;

- Figure 3 is a longitudinal section along the line A- A of the portion of the exhaust system shown in Figure 2 ;

- Figure 4 is a cross-section of the silencer of the exhaust system shown in Figure 2;

- Figure 5 schematically illustrates an example of a forming casing used in the method to produce the insert illustrated in Figure 1 according to the present invention;

- Figures 6 and 7 illustrate two steps of the method according to the present invention;

Figure 8 is a schematic perspective view of an interweaving device cooperating with a forming casing during a step of the method according to the present invention;

- Figure 9 shows a side elevation view and a front elevation view, respectively, of the interweaving device and of the forming casing shown in Figure 8;

Figure 10 is a schematic perspective view, with parts removed for the sake of clarity, of a machine for producing the insert illustrated in Figure 1 ;

Figure 11 is a front elevation view, with parts removed for the sake of clarity, of the machine illustrated in Figure 10;

- Figure 12 is a schematic plan view, with parts removed for the sake of clarity, of the machine illustrated in Figure 10;

- Figure 13 is a schematic front elevation view, with parts removed for the sake of clarity, of a machine for producing the insert illustrated in Figure 1, according to a first alternative embodiment;

- Figure 14 is a perspective view of an interweaving device and of the forming casing, with parts removed for the sake of clarity, according to a first alternative embodiment;

- Figure 15 is a schematic side elevation view, with parts shown as cross-sectional views and parts removed for the sake of clarity, of the interweaving device and of the forming casing shown in Figure 14;

- Figure 16 is a schematic front elevation view of a machine for producing the insert according to a second alternative embodiment;

- Figure 17 is a perspective view of the interweaving device and of the forming casing according to the second alternative embodiment; - Figure 18 is a schematic side elevation view, with parts shown as cross-sectional views and parts removed for the sake of clarity, of the interweaving device and of the forming casing shown in Figure 16;

- Figure 19 schematically illustrates an exploded view of an insert produced according to the present invention, which is fitted to a portion of a line of the vehicle exhaust system in order to act as a heat shield; while

- Figure 20 is a schematic view, with parts shown as cross-sectional views and parts removed for the sake of clarity, of an insert produced according to the present invention, which is fitted to a portion of an engine of the vehicle in order to act as a heat shield.

BEST MODE FOR CARRYING OUT THE INVENTION

The present invention will now be described with reference to the accompanying Figures in sufficient detail for those skilled in the art to produce and use it. Persons skilled in the art will be able to implement various modifications to the embodiments described herein and the general principles disclosed herein could be applied to other embodiments and applications without departing from the scope of the present invention, as disclosed in the appended claims. Accordingly, the present invent is not to be limited in scope to the embodiments described and illustrated herein, but is to be accorded with the widest scope consistent with the principles and characteristics disclosed and claimed herein.

With reference to Figure 1, denoted as a whole by reference numeral 1 is an insert structured to acoustically and/or thermally insulate component parts of a vehicle provided with an internal combustion engine.

It is understood that "component part" means any component (s) of the vehicle, such as for example parts of the engine, or of the fuel tank or any other part of the vehicle which needs to be thermally and/or acoustically insulated .

According to the embodiment illustrated in Figures 1 and 2, the insert 1 is structured to be mounted/installed in an acoustic chamber 2a of a silencer 2 of an exhaust gas system of an internal combustion engine of a vehicle to cover the exhaust pipes/perforated walls/ducts/lines 3 present/connected to/passing through said acoustic chamber 2a in order to attenuate the noise/heat of the gases flowing through said pipes/perforated walls/ducts/lines 3. It should also be pointed out that the present invention is not limited to an insert 1 that is inserted inside the acoustic chamber 2a of the silencer 2, but that, alternatively, the insert 1 could be designed as an external cover for a duct of the exhaust system 3 and to be placed under a plate or shell or half-shell of a heat shield present on the outside of said duct. For example, as illustrated in the example in Figure 19, a heat shield 50 may comprise at least one protective half-shell 51 made of a rigid material, for example metal, shaped in such a way as to coat/cover at least a section or portion of the outer surface 52 of a duct 53 of the exhaust system 3, and at least one insert 1, which is arranged between the inner surface of the shell 51 and the portion of outer surface 52 in order to thermally and/or acoustically insulate the duct 53.

It is understood that according to an alternative embodiment, the insert 1 could be part of a heat shield fitted in the engine, for example on parts inside the engine compartment, or directly on the engine. For example, Figure 20 illustrates a heat shield 60 comprising a protective shell 61 made of a rigid material, for example metal, shaped in order to be arranged to face a stretch or portion of the outer surface 62 (schematically illustrated by a broken line) of one or more components to be thermally and/or acoustically insulated arranged for example inside the engine compartment and/or comprised within the engine, and an insert 1 that is housed inside the protective shell 61.

It is understood that the shape/dimensions of the insert 1 produced according to the present invention are not limited to the shape/dimensions of the insert 1 illustrated in the example in Figures 1 and 2, and that these may be different, that is to say they may be modified based on the inner shape of the acoustic chamber 2a or based on the number, shape/section and position of the ducts inside the chamber 2a.

According to a preferred embodiment illustrated in Figures 1-4, the insert 1 comprises a skein or mattress of flexible fibres F, preferably flat, of a shape that is substantially complementary to the inner shape of the acoustic chamber 2a destined to receive it so as to fill it and acoustically/thermally insulate it. Preferably, but not necessarily, the fibre mattress which forms the insert 1 may be rectangular, elliptical, round, kidney-shaped or any other similar shape in order to follow the space inside the chamber 2a. The fibre mattress forming the insert 1 may preferably be provided with one or more through holes 4 dimensioned to house and envelop/cover, in use, respective exhaust ducts 3 passing through the silencer 2. It is understood that according to one possible embodiment, the insert 1 may have no openings.

The fibre mattress forming the insert 1 is formed of a plurality of sound-deadening fibres F preferably mineral fibres, which are interwoven by means of the method described in detail below. According to a preferred embodiment, the fibres F are continuous. Preferably, the continuous fibres are joined seamlessly so as to form a single thread. Preferably, the fibres F may be wound around one or more axes so as to substantially form a skein/coil. According to a preferred embodiment described by way of example, the fibres of the insert 1 are voluminized and/or texturized.

Nonetheless it is important to point out that according to a different embodiment, the fibre mattress forming the insert 1 may comprise discontinuous fibres F (pieces), or portions of fibres (separate from one another) each of a reduced length. Preferably, but not necessarily, the length of the discontinuous fibres F may be, for example, comprised between 1 cm and 30 cm.

The fibres F which make up the insert 1 may comprise any type of mineral fibre that is suitable for attenuating the noise/heat, preferably associated with the exhaust gases flowing through the ducts 3. Preferably, the fibres F may comprise for example, glass fibres, basalt fibres, silica fibres or any other type of similar mineral fibre having sound-deadening and/or thermal insulation properties and which can be installed preferably in a silencer 2.

According to an alternative embodiment the fibres F may conveniently comprise fibres of synthetic material containing polystyrene and/or polypropylene and/or polyamide and/or Kevlar and/or carbon and/or aramid and/or cotton and/or any other type of similar synthetic material.

According to an alternative embodiment, the fibres F may conveniently comprise metal fibres, preferably steel, for example stainless steel. Preferably the metal fibres may have a thickness comprised between approximately 6 and 400 micron. It is understood that the insert 1 may comprise one or more of the types of fibres described above. According to an alternative embodiment, the insert 1 may comprise continuous fibres and discontinuous fibres.

In the example illustrated in Figures 1-4, the mattress forming the insert 1 is substantially elliptical in shape and the two larger opposite surfaces are substantially flat and parallel to one another. The sound- deadening insert 1 is further provided with an opening 4 designed to cover a duct 3. It is understood that the number of openings 4 in the insert 1 may vary according to the number of ducts 3 to be covered. Thus, the insert 1 may have no openings 4 if there are no ducts 3, or it may have one or more openings 4. Further, it is understood that the two larger surfaces of the insert 1 may be curved and not parallel to one another. According to an embodiment that is not illustrated, at least one of the two larger surfaces may be convex/rounded towards the outside or towards the inside of the casing 5. With reference to Figures 5-9, the steps of the method for producing the sound-deadening insert 1 according to the present invention will now be described.

According to a possible embodiment, the method consists of providing a mould or matrix that is preferably closed, hereinafter referred to as the forming casing 5, comprising a frame 6 preferably in the form of a plate provided internally with a seat 7, which is shaped so as to substantially complement the shape of the insert 1 to be produced and is closed/delimited on opposite sides by two corresponding walls 8 at least one of which is perforated (Figure 5), arranged so as to rest on and come into contact with the opposite larger surfaces of the frame 6; filling/loading/arranging a certain amount of fibres F in the seat 7 in order to obtain a previously defined density of fibres F (Figures 6 and 7); placing on the outside of the forming casing 5 an interweaving device 9 provided with penetrating means 10 facing at least one perforated wall 8 of the casing 5 (Figure 8); making the penetrating means 10 of the interweaving device 9 penetrate into the seat 7 of the casing 5 through the through holes 11 in the perforated wall 8 so as to impart on the fibres F displacements inside the seat 7 in order to interweave/twist said fibres F together and obtain a cohesive skein of fibres corresponding to the insert 1 (Figure 9); and lastly extracting the compact fibre skein forming the insert 1 from the seat 7 in the casing 5 (Figure 1) .

According to a preferred embodiment illustrated in Figures 8 and 9, the interweaving device 9 may comprise a needle-holder head 12 and a plurality of punching needles 13 in correspondence with the penetrating means 10 which are coupled to the needle-holder head 12 and are arranged so that, in use, they pass through the through holes 11 in order to penetrate into the seat 7 of the forming casing 5. According to a preferred embodiment illustrated by way of example in Figures 8 and 9, the needle-holder head 12 comprises a flat plate, while the punching needles 13 extend substantially orthogonally from the flat lower surface of the plate, so that, in use, they are arranged so as to be substantially orthogonal to a perforated wall 8 of the casing 5 to be crossed.

According to a preferred embodiment described by way of example and illustrated in Figures 8 and 9, the needle- holder head 12 is movable along a rectilinear direction A substantially parallel to the needles 13 and preferably orthogonal to the positioning plane of the wall 8 away from and towards the casing 5 so as to perform a reciprocating motion in opposite directions Al, A2.

According to a preferred embodiment described by way of example and illustrated in Figures 8 and 9, the method comprises the step of moving the needle-holder head 12 away from and towards the casing 5 along the direction A preferably vertically, according to a reciprocating motion Al, A2, so that the punching needles 13 pass through the through holes 11 obtained in the perforated walls 8 in order to pass through the fibres F contained in the seat 7 and thus needle punch them. Preferably, the needle-holder head 12 is moved so that the punching needles 13 are substantially intermittently withdrawn from and introduced into the seat 7 of the forming casing 5 through the openings 11 in the perforated wall 8. It is understood that the present invention is not limited to the displacement of the needle-holder head 12 described above, but may alternatively and/or additionally envisage a displacement of the casing 5 along the axis A according to a reciprocating motion Al, A2.

The Applicant has found that needle punching of the fibres contained inside the preformed seat 7 in the forming casing 5 guarantees a precise and conveniently compact form of the insert 1. The attainment of a precise shape makes it possible to simplify the installation of the insert 1 in the silencer 2, and thus reduce installation times and the respective production costs.

According to a possible embodiment described by way of example, the needles 13 may be arranged so as to be spaced between approximately 0.5 cm and 2 cm apart, preferably 1 cm apart. Preferably, the needles 13 may be distributed on the head 12 so as to have a density of approximately one needle per cm 2 .

As shown in the example illustrated in Figure 1, the insert 1 obtained using the method according to the present invention is preferably needle punched over substantially the entire outer surface area of the two largest opposite surfaces. In other words, in this example, needle punching is performed so as to cover/involve the entire area of the two opposite larger surfaces of the insert 1. Needle punching of the entire surface of the insert achieves: a more compact insert 1 which makes it easier to install in the silencer 2, a uniform distribution of the fibres F in the silencer 2, and a significant reduction in waste production, owing to the fact that the inserts open up much less during installation.

With reference to a preferred embodiment illustrated by way of example in Figure 5, the forming casing 5 may be closed and made of a rigid material, that is to say a solid and compact material that is impenetrable by needles (or jets of pressurized air or water), preferably metal, for example steel or aluminium or similar materials. The casing 5 may comprise a shell that is substantially parallelepiped in shape and comprises a frame 6 that is preferably substantially rectangular in shape provided, in turn, with an inside edge delimiting the inner lateral surface of the seat 7, and two opposite larger flat surfaces, outside the seat 7 resting upon and in contact with which are the two perforated walls 8 that delimit the seat 7 at the two opposite free sides. Preferably, the two walls 8 may be arranged so as to face one another at a distance that is substantially equal to the thickness of the insert 1.

According to one embodiment, the openings 11 in the walls 8 comprise through holes, preferably having a circular cross-section, each of which is associated with a corresponding punching needle 13. It is understood that each opening 11 is dimensioned/shaped so as to be crossed, in use, by a corresponding punching needle 13 movable in the direction A. Moreover, it is understood that the present invention is not limited to openings 11 consisting of round through holes, but may envisage openings 11 having a different cross-section (in relation to the axis of the hole) , such as for example, elliptical, star-shaped, cross- shaped, or the like. The Applicant has found that elliptical or star-shaped or cross-shaped openings advantageously permit the compactness of needle punching to be increased. For that purpose, according to a possible embodiment, the casing 5 may be translated/displaced along at least one direction B transverse to the direction A in order to modify the point at which the punching needles 13 penetrate into the openings 11 and thus the fibres F. It is important to point out that the casing 5 may undergo a plurality of displacements along the direction B, at the end of each of which it is penetrated by the needles 13. According to a possible embodiment, the displacement ( s ) may be performed according to a reciprocating motion in two opposite directions Bl, B2.

It is understood that according to another embodiment, alternatively or in addition to the casing 5, the needle- holder head 12 may be translated, with respect to the casing 5, one or more times along at least one direction B transverse to the direction A, preferably according to a reciprocating motion in the two opposite directions Bl and B2, in order to modify the point at which the punching needles 13 penetrate into the openings 11/fibres F.

It is understood that the present invention is not limited to the transverse displacement of the casing 5 and/or of the needle-holder head 12 along a single direction B, but may envisage a plurality of displacements (not illustrated) along different directions but all on a common plane orthogonal to the direction A, in which the directions depend on the shape of the openings 11. For example, in the case in which the casing 5 comprises walls 8 provided with elliptical openings 11 in which the major semiaxes of the ellipses are parallel to one another (as illustrated in Figures 5-8), the method may comprise, between two successive penetrations, preferably when the needles 13 are in a retracted position outside of the casing 5, the step of displacing/translating the casing 5 by a few millimetres along a direction B parallel to the semiaxes of the ellipses/openings 11. In the case in which the casing 5 comprises one or two walls 8 provided with cross-shaped openings 11 in which the axes of the cross are orthogonal to one another, the method may comprise, between two successive penetrations, the step of displacing/translating the casing 5 by a few millimetres along two orthogonal directions parallel to the two axes of the cross.

According to an alternative embodiment (not illustrated) , each opening 11 may be dimensioned so as to be crossed simultaneously by two or more needles 13. For example, the openings 11 may consist of elongated slits that extend in the wall 8 of the casing 5 along rectilinear directions parallel to and at a distance from one another, while the needles 13 may be arranged so as to form rows parallel to corresponding slits so that during the displacement of the head 12 along the direction A, a series of needles 13 belonging to the same row penetrate the casing 5 through the same slit. According to a preferred embodiment, the casing 5 preferably, but not necessarily, further comprises a profile or template 15, which is arranged inside the seat 7 and has the purpose of shaping/forming/modelling an opening 4 in the insert 1. According to a preferred embodiment described by way of example, the template 15 may comprise a tubular element that extends inside the seat 7 between the two walls 8 with its axis orthogonal to said walls 8, the shape, dimensions and position of said tubular element in the seat 7 corresponding to (following) the shape, dimensions and position of the duct 3 to be wrapped inside the cavity 2a of the silencer 2. The cross-section of the tubular element may be round or elliptical or square or rectangular or any shape corresponding to that of the duct 3. It is understood that the number of templates 15 in the casing 1 may be the same as the number of the corresponding ducts 3 to be covered inside the cavity 2a.

According to a preferred embodiment, at least one of the perforated walls 8 is coupled to the frame 6 so as to be able to rotate about an axis C between an open position (Figures 5 and 6) and a closed position of the seat 7 (Figure 7) . In the example illustrated in Figures 5-8, the perforated upper wall 8 has one side hinged to a lateral edge of the frame 6 so as to act as a cover. It is understood that the present invention is not limited to a rotating/openable perforated wall 8, preferably hinged to the frame 6, but could envisage other solutions in which the wall 8 is detachably joined to the frame 6 so that the seat 7 can be selectively closed/opened. Moreover, it is understood that in the embodiment wherein the casing 5 comprises two perforated walls 8, the corresponding openings 11 obtained in said walls 8 are arranged in the same position and are coaxial with one another to allow the needles 13 to pass simultaneously through the upper plate 8, the seat 7, and the lower plate 8 during the displacement of the needle-holder head 12 so that the insert is needle punched through its entire thickness. It is understood that according to an alternative embodiment which envisages for example only one perforated wall 8, the needle-holder head 12 may be displaced in a controlled manner along the direction Ά so that the needles 13 only partially penetrate the casing 1 thus without coming into contact with the opposite wall 8.

According to a possible embodiment, the openings 11 may be arranged so that the axial distance between each one is comprised between approximately 0.5 cm and 2 cm, preferably 1 cm. Preferably, the openings 11 may have a width or diameter comprised between approximately 5 and 15 mm, preferably between 6 and 12 mm.

Figures 10-12 illustrate an example of an embodiment of a machine 20 for producing the sound-deadening insert 1 according to the method described above.

According to a possible embodiment illustrated in Figures 10-12, the machine 20 comprises: a frame 21 which is structured to stand on the ground and the upper part of which supports a supporting surface 22 that is preferably horizontal on which, in use, at least one forming casing 5 is arranged; the interweaving device 9, which is connected to the frame 21, preferably by means of a supporting element 23 which, in the example that is illustrated, extends upwards in a cantilevered fashion from a lateral edge of the supporting surface 22 and is structured to support and hold the interweaving device 9 substantially above the supporting surface 22 in a position such that it faces, in use, the upper perforated wall 8 of a casing 5 below it, which in turn rests on the surface 22.

According to a possible embodiment described by way of example and illustrated in Figure 10, the interweaving device 9 comprises the needle-holder head 12, a plurality of needles 13 associated with the head 12, and a supporting and actuating unit 24, permanently connected to/integrated with the upper end of the supporting element 23 and structured to displace the needle-holder head 12 along the direction A according to a reciprocating motion in the two directions Al, A2 away from and towards the supporting surface 22 so that the needles 13, in use, penetrate into the closed casing 5 below through the respective openings 11. The supporting and actuating unit 24 may comprise, for example, an electromechanical or pneumatic or hydraulic actuator (not illustrated) or a mechanical device for transmitting motion provided with a connecting rod and crank mechanism driven by an electric motor (not illustrated) in order to displace the needle-holder head 12 vertically, or any similar actuating system coupled to the needle-holder head 12 and designed to be controlled by an electronic control unit 26 to transmit the reciprocating motion Al, A2 along the rectilinear and, preferably, vertical direction A to the needle-holder head 12. It is understood that the present invention is not limited to a supporting and actuating unit 24 designed to displace the needle-holder head 12, but could additionally, or alternatively, according to different embodiments (not illustrated) displace the casing 5, for example by means of the supporting surface 22, along the direction A according to a reciprocating motion Al, A2, away from and towards the needle-holder head 12 in order to make the needles 13 penetrate into the fibres F.

According to a preferred embodiment illustrated in Figures 10-12, the machine 20 may be provided with a locking system 30 (schematically illustrated in Figure 10) structured to keep the casing 5 permanently locked in a predetermined position below the needle-holder head 12 during needle punching inside said casing 5. The locking system 30 may comprise for example clamping aws or hooks designed to clasp the sides of the casing 5 or an electromagnetic or hydraulic or pneumatic mould clamp or any similar locking system.

According to a possible embodiment, the machine 20 may further comprise an actuating unit 25 (only illustrated schematically in Figure 10) designed to make the casing 5 translate along at least the direction B preferably according to the reciprocating motion Bl, B2. The actuating unit 25 may comprise, for example, electromechanical or pneumatic or hydraulic actuators (not illustrated) or any similar actuating system coupled to the casing 5 to displace it along at least the direction B. Preferably, the actuating unit 25 may be structured to make the casing 5 perform one or more sequential translations on the supporting surface 22 along at least the direction B in which each translation may conveniently be comprised between approximately 1 mm and approximately 12 mm.

It is understood that according to an alternative embodiment, the actuating unit 25 may be configured to displace the needle-holder head 12 instead of, or in addition to, the casing 5 along the direction B according to the reciprocating motion Bl, B2.

According to one example of an embodiment, the actuating unit 25 may comprise a rack or belt or screw/piston or similar mechanism, arranged, for example at the side of the supporting surface 22, and structured to make the casing 5 translate by a few millimetres, according to the reciprocating motion Bl, B2 described previously. It is understood that the screw-piston mechanism may be provided with a system for clamping/coupling it to the casing 5 (not illustrated) structured to connect the latter to said screw-piston mechanism.

According to a preferred embodiment illustrated in Figures 10-12, the machine 20 may comprise one or more rectilinear rails or guideways 31 extending parallel to one another on the supporting surface 22 parallel to the longitudinal axis K of said surface 22, shaped so as to make the casing 5 slide, in use, from a loading area 22a of the supporting surface 22 in which the casing 5 is positioned for filling the fibres in the seat 7, towards a work area 22b below the interweaving device 9. According to a preferred embodiment described by way of example, the machine 20 may comprise an electromechanical member (not illustrated) that displaces the casing along the two guideways 31 controlled by the control unit 26 between the loading area 22a and the work area 22b. In the example that is illustrated, the guideways 31 have a substantially rectangular cross-section. However according to an alternative embodiment illustrated by way of example in Figures 8, 14 and 17, the guideway 31 may have a C-shaped cross-section and be dimensioned to receive and clasp the lateral edge of the casing 5. In this case, the supporting surface 22 may not be provided with the central supporting surface, and the machine 20 may comprise the two C-shaped lateral guideways 31 which would thus have the function of supporting and sliding the casing 5 between the loading area 22a and the work area 22b and preferably the function of locking said casing 5 in the work area 22b.

According to a possible embodiment illustrated in Figures 10 and 11, the machine 20 preferably comprises one or more suction devices 18 each of which is structured so as to suck air out through the openings 11 in a perforated wall 8 of the casing 5 in order to cause the fibres to be sucked into and/or held in the seat 7. According to a preferred embodiment described by way of example and illustrated in Figure 8, the suction device 18 comprises at least a suction head 28 which may be connected to a suction system 27, for example a vacuum pump/system or a suction pump (not illustrated), by means of a suction line 29. According to a possible embodiment described by way of example and illustrated in Figure 10, the suction head 28 is provided with a suction aperture or inlet arranged so as to rest on the lower surface of at least a perforated portion of the supporting surface 22 on the side opposite the supporting surface of the casing 5. The perforated portion of the surface 22 may preferably, but not necessarily, be arranged in a loading area 22a of said supporting surface 22.

In use, the casing 5 may be arranged so as to rest on a loading area 22a of the supporting surface 22, the upper perforated plate 8 hinged to the frame 6 is opened in order to open the upper side of the seat 7; the fibres are loaded into the seat 7 in order to obtain a given density and the suction system 27, if present, may be activated to facilitate the positioning and holding in place of the fibres in the seat 7. When the fibres F have been loaded, the upper perforated plate 8 is put back in place so as to rest on the frame 6 and thus close the fibres in the seat 7, and the forming casing 5 is displaced, automatically by means of the electromechanical member, or manually, preferably along the guideway(s) 31 from the loading area 22a to the work area 22b. According to a preferred embodiment in which the needle-holder head 12 is movable with respect to the casing 5, the control unit 26 operates the support and actuator unit 24 to displace the needle- holder head 13 in the direction A according to the reciprocating motion Al, A2, and activates the actuator unit 25 to displace the casing in the direction B according to the reciprocating motion Bl, B2 in order to carry out the needle punching of the fibres F inside the casing 5. When the needle punching is complete, the casing 5 is moved manually or automatically into the loading area 22a where the casing 5 is opened in order to remove the insert 1 from the seat 7. The insert 1 is then installed in the chamber 2a of the silencer 2.

From the above description it is thus evident that the present invention achieves the intended aims.

The embodiment illustrated in Figures 13-15 relates to a machine 35, which is similar to the machine 20 and in which, where possible, the components are denoted using the same reference numerals used to denote the corresponding parts of the machine 20. The machine 35 differs from the machine 20 in that the interweaving device 9 comprises a nozzle-holder head 36, and a plurality of water nozzles 37 for emitting jets of pressurized water directed towards the casing 5 below. The nozzles 37 are connected to a pressurized water generating system 38, by means of a pressurized water delivery line 39. In use, the jets of pressurized water generated by the nozzles 37 penetrate into the casing 5 through the openings 11 in the perforated wall 8 so as to impart on the fibres F crosswise displacements inside the seat 7. Such displacements interweave/twist the fibres F together so as to compact them and obtain a compact skein of fibres corresponding to the insert 1.

The embodiment illustrated in Figures 16-18 relates to a machine 40, which is similar to the machine 20 and in which, where possible, the components are denoted using the same reference numerals used to denote the corresponding parts of the machine 20.

The machine 40 differs from the machine 20 in that the interweaving device 9 comprises a nozzle-holder head 41, and a plurality of air nozzles 42 for emitting jets of pressurized air directed towards the casing 5 below. The air nozzles 42 may be connected to a pressurized air generating system 43, for example a compressor, by means of a pressurized air delivery line 44. In use, the jets of pressurized air generated by the nozzles 42 penetrate into the casing 5 through the openings 11 in the perforated wall 8, so as to impart on the fibres F displacements inside the seat 7 in order to interweave/twist said fibres together so as to compact them and obtain a compact skein of fibres corresponding to the insert 1.

Lastly, it is important to point out that the use in the present invention of a forming casing 5 made of a compact and solid material, rather than a soft material, which the needles can easily penetrate, is extremely advantageous in that, on one hand, the same casing can be used with all the penetrating means envisaged by the invention, that is to say needles, water and air, and on the other, it completely eliminates the risk of damage and wear, also thanks to the presence of the through holes.

Moreover, the use in the present invention of a forming casing 5 made of a compact and solid material and the presence of the through holes eliminates the risk of particles of the casing coming away and their consequent depositing in/contamination of the fibres of the insert by the needles.

Lastly, it is clear that modifications and variations may be made to the method, the machine and the insert described and illustrated herein without departing from the scope of the present invention, as set forth in the appended claims.