DE102017102979B4 - Device for reducing noise emissions and method for producing this device - Google Patents

Abstract

Device (1) for reducing sound emissions from a sound source (2), which is arranged in particular in and / or on a vehicle, characterized in that the device (1) has a layer arrangement (3) comprising a first layer (4) and a has a second layer (5), the first layer (4) lying against the second layer (5) without being bonded to the second layer (5) and the layer arrangement (3) spiraling the sound source (2) in a circumferential direction (17 ) of the sound source (2), wherein the device (1) has at least a first side wall (6) with a first end face (8) and a first air duct (14) and at least a second side wall (7) with a second end face (9) and a second air duct (15), a first normal vector (10) of the first end face (8) and a second normal vector (11) of the second end face (9) being perpendicular to the circumferential direction (17), the first air duct (14) and the second air duct (15) in R direction of the corresponding normal vectors (10, 11) are meandering.

Description

The invention relates to a device for reducing noise emissions and a method for producing such a device.

Measures for sound insulation are known from the prior art, which are based on the concept of partitioning off or encapsulating the sound source. Such a capsule usually consists of a relatively thick, rigid housing, for example made of sheet metal.

In addition, the inner surfaces of the housing can be lined with sound-absorbing materials in order to dampen the sound waves emitted by the sound source. This primarily reduces the excitation of the housing and thus the formation of structure-borne noise. This leads to a lower radiation of the airborne sound from the outer surfaces of the encapsulation and thus to a lower perceptible volume of the sound source.

For this reason, reducing the structure-borne noise of a capsule is of great importance. For the substantial reduction of structure-borne noise, generally more layered plates are used for the construction of the housing, which have a non-detachable series of heavy and soft materials in cross section. The panels are firmly connected to each other to prevent airborne noise from spreading through the joints. A fixed cross-section of the capsule is formed by the fixed connection of the plates to one another, but the sound-insulating effect of the acoustic low-pass filter thus created is reduced by increasing the rigidity around the joints.

In order to further increase the sound-insulating effect of the encapsulation, high densities of the heavy materials and lower spring rates of the soft materials are sought. With the finite density of conventional materials, the effect of the low-pass filter can be further increased by increasing the wall thickness. Increasing the volume increases the mass. However, increasing the wall thickness leads to a disproportionate increase in the rigidity of the panel and thus to a reduction in the sound insulation.

US 6 062 033 A shows a device for reducing noise emissions of an air conditioning system. Such a device is known, wherein a layer device with a first layer and a second layer can be seen, which is rolled up in a spiral.

US 5 271 142 A , JP 2003 - 162 284 A and EP 0 732 684 A2 each show that the layers can lie against each other without bonding. It is therefore an object of the present invention to achieve an increase in the sound-insulating effect of the acoustic encapsulation for sound sources, in particular for small to medium-sized sound sources such as compressors, pumps, gears, etc.

This object is achieved in accordance with the features of patent claim 1.

An important point of the invention is to provide a device for reducing sound emissions from a sound source, which is arranged in particular in and / or on a vehicle, the device having a layer arrangement comprising a first layer and a second layer, wherein the the first layer is in contact with the second layer without a bond with the second layer, and the layer arrangement spirally encases the sound source in a circumferential direction of the sound source.

The wording “without composite” is to be understood here in such a way that no materials are arranged between the first layer and the second layer of the device, or methods have been used to connect the first layer and the second layer to one another. An example of this is an adhesive or the welding process in order to connect the first and second layers to one another. According to the invention, such materials or processes have been dispensed with.
In the present case, the first and second layers are therefore at most non-positively connected to one another due to frictional forces, since a non-positive connection cannot be avoided with layers lying on one another.
According to the invention, the layer arrangement is, as described above, wrapped spirally around the sound source such that the sound source is covered in the circumferential direction. The sound source is particularly advantageously sheathed several times by the layer arrangement, where multiple can mean at least two, three, four, etc.

In particular, a dissolution of the spiral structure can be prevented if a first end of the first layer is connected to at least one of the side walls and a second end of the first layer is connected to a partial surface of the first layer, whereby a dissolution of the spiral arrangement can be avoided.

The device according to the invention therefore forms a spiral structure which, from a mechanical point of view, represents an open profile, but from an acoustic point of view it is seamless and without an increase in stiffness represents a closed profile.

According to the invention, the encapsulation of the sound source consists of layers that are not connected to one another, which causes a substantial increase in the thickness of the encapsulation, but, due to the non-connection of the layers and the mechanically open profile of the device or the encapsulation, only causes a slight increase in the rigidity .

According to a particularly preferred embodiment, the first layer therefore consists of a different material than the second layer. The material of the first layer is preferably a heavier material than the material of the second layer. The first layer particularly preferably consists at least partially of an elastomer and / or bitumen, and the second layer at least partially of a softer material than the material of the first layer, which can in particular be an open-pore material, for example of a foam, cotton-like or fleece -like material.

This type of construction therefore enables a substantial increase in the thickness of the encapsulation or of the device, but only causes a slight increase in the rigidity, as a result of which better isolation of the sound source is possible by increasing the volume.

According to the invention, the insulation of the sound source is further increased by the device having at least one first side wall with a first end face and at least one second side wall with a second end face, a first normal vector of the first end face and a second normal vector of the second end face being perpendicular to the circumferential direction .

These additional side walls make it possible to cover the areas which are not enclosed by the layer arrangement and to further isolate the sound source.

According to a further preferred embodiment, the sound insulation of the sound source can be further improved if the first side wall has a first peripheral surface and the second side wall has a second peripheral surface, the first peripheral surface and the second peripheral surface being at least partially connected to the first layer or the second layer are, wherein the peripheral surfaces are preferably connected to the second layer, ie the layer with the softer material, whereby a further improvement of the sound insulation is possible.

As a result, the first layer is connected to the circumferential surfaces, as a result of which the first layer can make a first revolution of the spiral along the circumferential surface, as a result of which a further improvement in the sound insulation can be achieved since a seamless connection between the layer arrangement and the side walls can be achieved.

It is particularly advantageous if the first layer is completely or almost completely connected to the peripheral surfaces. Nearly complete is to be understood to mean that the peripheral surfaces or the side walls can have recesses, which then cannot be connected to the first layer.

According to the invention, it is provided for the operation of the sound source that the first side wall has a first air duct and the second side wall has a second air duct.

• durch den ersten Luftkanal, und die durch die Abwärme der Schallquelle erwärmte Luft durch den zweiten Luftkanal abgeführt wird.

For cooling the sound source, in particular when the sound source is operating, it is helpful if fresh air can penetrate from outside into the encapsulation, for example

• through the first air duct, and the air heated by the waste heat from the sound source is discharged through the second air duct.

The first and second air channels, on the other hand, mean that the encapsulation opens from the inside, that is from the sound source, to the outside. However, in order to continue to achieve the best possible sound insulation, it is provided according to the invention that the first air duct and the second air duct are meandering in the direction of the corresponding normal vectors of the end faces.

Due to the meandering design of the air channels, the sound emitted by the sound source is reduced by reflections on the walls of the air channels and absorption of the sound by the material of the side walls. In particular, it is advantageous if the materials from which the side walls are made are as sound-absorbing as possible. It is also alternatively conceivable that the side walls, like the layer arrangement, are composed of a first and a second layer. It is particularly preferred here if the air channels are arranged to run in the second layer, that is to say in the layer with the softer material.

For the compactness of the device, it is particularly advantageous according to a further embodiment if the sound source is connected to both the first side wall and the second side wall of the device.

In particular, it is considered sensible if the sound source is dampened and / or spring-loaded at least in relation to one of the side walls. Even more advantageously, the sound source is dampened and / or suspended in a swinging and swinging manner relative to the first and second side walls. In this way it can be avoided or at least reduced that sound waves due to vibrations of the sound source are transmitted to the side walls of the device and further sound waves are generated by the excitation of the side walls which can have a disadvantageous effect on the overall volume of the device with the sound source.

According to a further preferred embodiment, the compactness of the device can be increased further if the first end face and the second end face are essentially of identical design and have a circular, oval, elliptical or rectangular configuration. The phrase "essentially" is to be understood in such a way that the end faces are identical except for recesses, receptacles and passages. However, it is also conceivable that the side surfaces are designed differently, for example in order to isolate conically shaped sound sources.

It is further advantageous if the first side wall and the second side wall are of identical design. Thus, the manufacturing cost can be further reduced because a manufactured side wall can function both as a first side wall and as a second side wall.

According to a particularly preferred embodiment, it is advantageous if the layer arrangement is arranged repetitively at least three times when viewed in a radial direction of the sound source. Calculations of the equivalent continuous sound level L _eq , which is given in dB (A), for the device according to the invention and the characteristic of the A-weighting filter used have shown that by repeating the layer arrangement three times in the radial direction, both a good reduction in the sound level and a adequate compactness of the device is given. Repeating the layer arrangement three times is particularly advantageous for low-frequency sound sources. For sound sources in the medium or high frequency range, increasing the repetition can lead to even better sound insulation of the sound source.

A radial direction is understood to mean a direction that points away from the sound source in a certain direction.

The layer thickness of the layer arrangement is preferably 25 mm, more preferably 15 mm and particularly preferably 10 mm. The ratio of the layer thickness of the first layer to the layer thickness of the second layer is particularly preferably 0.25. For example, if the layer thickness of the first layer is 2 mm, the layer thickness of the second layer should be 8 mm. be.

1. a) Bereitstellen einer Schichtanordnung durch Auflegen einer ersten Schicht auf einer zweiten Schicht ohne Verbund zwischen der ersten Schicht und der zweiten Schicht;
2. b) Befestigen eines ersten Endes der ersten Schicht mit einer ersten Seitenwand und mit einer zweiten Seitenwand der Vorrichtung;
3. c) Umwickeln der Schallquelle mit der Schichtanordnung in einer Umfangsrichtung der Schallquelle, wobei die erste Schicht mit der ersten und der zweiten Seitenwand zumindest in Wirkkontakt steht;
4. d) Befestigen eines zweiten Endes der ersten Schicht mit einer Teilfläche der ersten Schicht, welche in einer radialen Richtung der Schallquelle gesehen unterhalb des zweiten Endes der ersten Schicht angeordnet ist.

Furthermore, a method for producing a device for reducing sound emissions from a sound source is described according to the invention, comprising the method steps

1. a) providing a layer arrangement by placing a first layer on a second layer without a bond between the first layer and the second layer;
2. b) securing a first end of the first layer to a first side wall and to a second side wall of the device;
3. c) wrapping the sound source with the layer arrangement in a circumferential direction of the sound source, the first layer being at least in operative contact with the first and second side walls;
4. d) attaching a second end of the first layer to a partial surface of the first layer, which is arranged below the second end of the first layer, viewed in a radial direction of the sound source.

The layer arrangement is correspondingly wound through the first and second side walls onto the first and second side walls. The shape of the side walls essentially dictates the shape of the device.

The attachment of the first end of the first layer to the side walls or to a partial area of the first layer can be achieved, for example, by adhesives. It is also conceivable to use adhesive strips.

Further advantageous embodiments result from the subclaims.

• 1A eine Seitenansicht einer erfindungsgemäßen Vorrichtung mit Schallquelle;
• 1B eine weitere Seitenansicht der Vorrichtung;
• 2 eine perspektivische Ansicht der Schallquelle mit Lagerung;
• 3 eine Vorderansicht der 2;
• 4 eine weitere Vorderansicht der Vorrichtung;
• 5A Kraft- und Wegamplituden gemäß dem Stand der Technik;
• 5B Kraft- und Wegamplituden gemäß der vorliegenden Erfindung;
• 6 äquivalenter Dauerschallpegel gemäß verschiedener Ausführungsformen;
• 7 Dämpfung einer Schallquelle der Erfindung im Vergleich zum Stand der Technik.

Further objects, advantages and expediencies of the present invention can be found in the following from the description in conjunction with the drawings. Here show:

• 1A a side view of a device according to the invention with sound source;
• 1B another side view of the device;
• 2nd a perspective view of the sound source with storage;
• 3rd a front view of the 2nd ;
• 4th another front view of the device;
• 5A Force and displacement amplitudes according to the prior art;
• 5B Force and displacement amplitudes according to the present invention;
• 6 equivalent continuous sound level according to various embodiments;
• 7 Attenuation of a sound source of the invention compared to the prior art.

The 1A shows a device according to the invention 1 in a first side view without a first side wall 6 so the sound source 2nd can be seen. Behind the sound source 2nd is the second side wall 7 to recognize.

Next is a layer arrangement 3rd the device 1 to recognize which in a circumferential direction 17th around the sound source 2nd is spirally wound and the sound source 2nd thus encased. The layer arrangement 3rd includes a first layer 4th and a second layer 5 , the first layer 4th without bond with the second layer 5 on the second shift 5 is present.

At the first shift 4th it is preferably a heavier material than the second layer. In particular, the first layer 4th higher bending stiffness than the second layer 5 on. The first layer 4th preferably consists at least partially of an elastomer or bitumen, the second layer 5 at least partially of a softer material than the material of the first layer 4th such as a foam or the like.

The 1 B shows a side view as well as that 1A , but here is the first sidewall 6 to recognize. As can be seen further, the first side wall 6 a first exit opening 18th of a first air duct 14 (not shown here) which are in contact with the surroundings. There is also a recess 19th to recognize by means of which it is possible to establish supply connections 20 (not shown here) to the sound source 2nd to produce, for example, to supply the sound source with energy or a required working medium.

The 2nd shows the sound source 2nd which with the first side wall 6 and the second side wall 7 connected is. Storage is an example 21 the sound source 2nd with the second side wall 7 presented in more detail here.

Again 2nd , which shows a perspective view of the device, can be seen, is on a third end face 26 a rib support element on the second side wall 25th arranged, being on the rib support member 25th , which is circular, inner ribs on the inside 24th and outer ribs on the outside 23 are arranged. The outer ribs 23 extend from the rib support member 25th rectilinear in the direction of the second peripheral surface 13 the second side wall 7 , causing an enlargement of the second peripheral surface 13 can be achieved. End ranges 27 the outer ribs are formed in such a way that they have the same shape as the adjoining region of the second peripheral surface 13 .

A swinging and damping or springy bearing 21 the sound source 2nd opposite the second side wall 7 the inner ribs can be reached 24th made of a material that has certain damping or suspension properties, such as rubber or the like.

Warehousing 21 the first side wall 6 is according to the storage of the second side wall 7 designed, the shape of the storage course of each to the shape of the sound source 2nd is adjusted.

Further are the 2nd second outlet openings 22 of the air ducts 14 , 15 recognizable which on the third face 26 or a fourth end face 28 (not shown here) the first side wall 6 are arranged. Around the second outlet 22 around is a cylindrical air flow restriction element 29 arranged, which with the respective side wall 6 , 7 connected is. The air flow restriction element 29 extends in the direction of the first or second normal vector 10th , 11 .

The air flow restriction element 29 serves to avoid suction or blow-out effects of the second outlet openings 22 compared to the layer arrangement 3rd , because of the air flow restriction element 29 the air flow from or into the second outlet openings 22 is directed and so a direct impact on the layer arrangement 3rd can be prevented. In addition, it is also conceivable that the air flow limiting element 29 can be used as a holder for an airflow conveying element (not shown here), such as a fan, so that an airflow can be actively established from the surroundings to the sound source and from the sound source to the surroundings.

The 3rd shows the subject of 2nd in a front view. From the 3rd the principle of action of the air flow limiting elements is even better 29 to recognize.

The 4th shows a structure similar to that 3rd , being partially in the area of the first side wall 6 a section through the side wall 6 is shown and further part of the layer arrangement 3rd is recognizable.

Of the 4th is an exemplary embodiment of a first air duct 14 refer to. There is a first exit opening to the surroundings 18th to the sound source 2nd towards at least a second outlet opening 22 shown. The first exit opening 18th goes into a first part of the air duct 31 over which is perpendicular towards 34 to the normal vector 11 is arranged progressively. To the first part of the air duct 31 closes via a passage opening 30th a second air duct part 32 which is also perpendicular in the direction 35 to the normal vector 11 is arranged progressively. The first air duct part 31 and the second air duct part 32 are through an intermediate element 33 separated from each other.

The 5A represents the current state of the art with a rigid encapsulation, in comparison 5B the subject of the present invention. From the prior art, represented schematically by the 5A , closed mechanical profiles are known in principle, the deformation of which is shown in the figure, which is accompanied by a significant increase in rigidity. In contrast to this, according to the invention, a device with a mechanically open profile can be used, which is nevertheless seamless from an acoustic point of view and has no or only a slight increase in rigidity.

This is in the 5A and 5B in particular by the respective path amplitude when the encapsulation is excited by a force with a force amplitude as shown.

From the representation of the 6 can be seen that by a device according to the invention 1 compared to a sound source without encapsulation by a device, a significant reduction in the continuous sound level is possible. It can also be seen that doubling the number of layers is not a significant improvement.

A comparison with the prior art is particularly that 7 refer to. An A weighting filter was applied to both frequency representations. Compared to the prior art, the device according to the invention was able to achieve a significantly improved reduction in volume.

All of the features disclosed in the application documents are claimed as essential to the invention, provided that they are new to the prior art, individually or in combination.

Reference list

1

contraption

2nd

Sound source

3rd

Layer arrangement

4th

first layer

5

second layer

6

first side wall

7

second side wall

8th

first face

9

second face

10th

first normal vector

11

second normal vector

12th

first peripheral surface

13

second peripheral surface

14

first air duct

15

second air duct

16

radial direction

17th

Circumferential direction

18th

first exit opening

19th

Recess

20

Supply connection

21

storage

22

second exit opening

23

outer ribs

24th

inner ribs

25th

Rib support element

26

third face

27

End area

28

fourth end face

29

Airflow restriction element

30th

Through opening

31

first air duct part

32

second air duct part

33

Intermediate element

34

direction

35

direction

36

first end

37

second end

Claims (7)

Device (1) for reducing sound emissions from a sound source (2), which is arranged in particular in and / or on a vehicle, characterized in that the device (1) has a layer arrangement (3) comprising a first layer (4) and a has a second layer (5), the first layer (4) lying against the second layer (5) without being bonded to the second layer (5) and the layer arrangement (3) spiraling the sound source (2) in a circumferential direction (17 ) of the sound source (2), wherein the device (1) has at least a first side wall (6) with a first end face (8) and a first air duct (14) and at least a second side wall (7) with a second end face (9) and a second air duct (15), a first normal vector (10) of the first end face (8) and a second normal vector (11) of the second end face (9) being perpendicular to the circumferential direction (17), the first air duct (14) and the second air duct (15) in Direction of the corresponding normal vectors (10, 11) are meandering. Device (1) after Claim 1 , characterized in that the first layer (4) consists of a different material than the second layer (5), the first layer (4) at least partially from an elastomer or bitumen and the second layer (5) at least partially from a softer one Material as the material of the first layer (4) exist. Device (1) after Claim 1 or 2nd , characterized in that the first side wall (6) has a first peripheral surface (12) and the second side wall (7) has a second peripheral surface (13), the first peripheral surface (12) and the second peripheral surface (13) at least partially with the first layer (4) are connected. Device (1) according to one of the Claims 1 to 3rd , characterized in that the sound source (2) is connected to the first side wall (6) and the second side wall (7) of the device (1). Device (1) according to one of the Claims 1 to 4th , characterized in that the first end face (8) and the second end face (9) are of substantially the same design and have a circular, oval, elliptical or rectangular design and the normal vectors (10, 11) are parallel or identical to one another. Device (1) according to one of the preceding claims, characterized in that, seen in a radial direction (16) of the sound source (2), the layer arrangement (3) is arranged repetitively at least three times. Method for producing a device (1) for reducing sound emissions from a sound source (2), comprising the method steps: a) providing a layer arrangement (3) by placing a first layer (4) on a second layer (5) without a bond between the first layer (4) and the second layer (5); b) securing a first end (36) of the first layer (4) to a first side wall (6) and a second side wall (7) of the device; c) wrapping the sound source (2) with the layer arrangement (3) in a circumferential direction (17) of the sound source (2), the first layer (4) being at least in operative contact with the first (6) and the second side wall (7) ; d) fastening a second end (37) of the first layer (4) with a partial surface of the first layer (4) which, viewed in a radial direction (16) of the sound source (2), below the second end (37) of the first layer ( 4) is arranged.

Images