DE102017102979A1 - Acoustic noise reducing device and method of making this device - Google Patents

Abstract

A device for reducing sound emissions of a sound source, which is arranged in particular in and / or on a vehicle, wherein the device has a layer arrangement comprising a first layer and a second layer, wherein the first layer without composite with the second layer at the second Layer abuts and wherein the layer arrangement spirally encases the sound source in a circumferential direction of the sound source.

Description

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

There are known from the prior art measures for sound insulation, which are based on the concept of foreclosure or encapsulation of the sound source. Such a capsule usually consists of a relatively thick, rigid housing, such as sheet metal.

In addition, the inner surfaces of the housing may be lined with sound absorbing materials to dampen the sound waves radiated from the sound source. As a result, especially the excitation of the housing and thus the formation of structure-borne noise is reduced. This leads to a lower emission of airborne sound from the outer surfaces of the enclosure and thus to a lower perceptible volume of the sound source.

For this reason, the reduction of structure-borne noise of a capsule is of great importance. For the substantial reduction of structure-borne noise multilayer plates are generally used for the construction of the housing, which have a non-detachable juxtaposition of heavy and soft materials in cross-section. The plates are fixed together to prevent the propagation of airborne sound through the joints. Due to the fixed connection of the plates with each other, a closed cross-section of the capsule is formed, but the sound-insulating effect of the resulting acoustic low-pass filter is reduced by increasing the rigidity around the joints.

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

It is accordingly an object of the present invention to achieve an increase in the sound-insulating effect of the acoustic enclosure for sound sources, in particular for small to medium-sized sound sources such as compressors, pumps, gears, etc.

This object is achieved according to the features of claim 1.

An essential point of the invention is to provide a device for reducing noise emissions of a sound source, which is arranged in particular in and / or on a vehicle, wherein the device has a layer arrangement comprising a first layer and a second layer, wherein the first layer without composite with the second layer abuts the second layer and wherein the layer arrangement spirally surrounds the sound source in a circumferential direction of the sound source.

Here, the term "without composite" is to be understood in this case such 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. As an example, an adhesive or the method of welding may be mentioned to join the first and second layers together. Such materials or methods have been omitted according to the invention.

In the present case, therefore, the first and the second layer are at most positively connected to one another due to frictional forces, since a frictional connection in the case of superimposed layers can not be avoided.

According to the invention, the layer arrangement, as described above, thus spirally wrapped around the sound source, so that the sound source is coated in the circumferential direction. Particularly advantageously, the sound source is coated several times by the layer arrangement, where multiple can mean at least twice, three times, four times, and so on.

In particular, dissolution of the helical structure can be prevented when a first end of the first layer is bonded to at least one of the sidewalls and a second end of the first layer is bonded to a partial surface of the first layer, whereby dissolution of the helical arrangement can be avoided.

By the device according to the invention therefore forms a helical structure, which represents an open profile from a mechanical point of view, however, seamlessly represents a closed profile in an acoustic view and without an increase in rigidity.

The encapsulation of the sound source according to the invention consists of layers not connected to one another, which is a significant enlargement due to the thickness of the encapsulant, but due to the non-bonding of the layers and the mechanically open profile of the device or encapsulation causes only a slight increase in rigidity.

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

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

According to a further embodiment, the insulation of the sound source can be further increased, that the device has at least a first side wall with a first end face and at least one second side wall with a second end face, wherein a first normal vector of the first end face and a second normal vector of the second end face 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, wherein the first peripheral surface and the second peripheral surface are at least partially connected to the first layer or the second layer are, wherein preferably the peripheral surfaces with the second layer, so the layer is connected to the softer material, whereby a further improvement of the sound insulation is possible.

As a result, the first layer is connected to the peripheral surfaces, whereby the first layer along the peripheral surface can perform a first rotation of the spiral, whereby a further improvement of 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 circumferential surfaces. Under almost complete is to be understood that the peripheral surfaces or the side walls may have recesses, which then just can not be connected to the first layer.

According to a further preferred embodiment, it is advantageous for the operation of the sound source when the first side wall has a first air channel and the second side wall has a second air channel.

For cooling the sound source, in particular during operation of the sound source, it is helpful if fresh air can penetrate from the outside into the enclosure to the sound source, for example through the first air duct, and the heated by the waste heat of the sound source air is discharged through the second air duct.

On the other hand, however, the first and the second air ducts mean an opening of the encapsulation from the inside, ie from the sound source, to the outside to the surroundings. However, in order to continue to achieve the best possible sound insulation, it is provided according to a further embodiment, that the first air channel and the second air channel are formed meandering in the direction of the corresponding normal vectors of the end faces.

Due to the meandering design of the air ducts, the sound emitted by the sound source is reduced by reflections on the walls of the air ducts and absorption of the sound by the material of the side walls. In particular, it is advantageous if the materials that make up the side walls are as sound-absorbing as possible. In this case, it is alternatively conceivable that the side walls as well as the layer arrangement are constructed consisting of a first and a second layer. In this case, it is particularly preferred if the air ducts in the second layer, ie in the layer with the softer material, are arranged to extend.

In particular, according to another embodiment, it is advantageous for the compactness of the device 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 useful if the sound source vibrating and oscillating at least with respect to one of the side walls is stored damped and / or sprung. Even more advantageously, the sound source is oscillating and oscillatingly damped and / or sprung relative to the first and second side walls. In this way, it can be avoided or at least reduced that sound waves are transmitted to the side walls of the device due to vibrations of the sound source and the sound of the sidewalls causes further sound waves, which can adversely affect the overall volume of the sound source device.

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

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

According to a particularly preferred embodiment, it is advantageous if viewed in a radial direction of the sound source, the layer arrangement is arranged at least three times repetitive. 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, as seen in the radial direction, by a three-time repetition of the layer arrangement both a good reduction of the sound level and a adequate compactness of the device is given. A three-time repetition of the layer arrangement is particularly advantageous for low-frequency sound sources. For sound sources in the medium or high frequency range, an increase in repetition can lead to even better sound insulation of the sound source.

A radial direction here is to be understood as a direction which points away from the sound source in a specific direction.

In this case, 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.

Further, a method for producing a device for reducing noise emissions of a sound source is described according to the invention, comprising the method steps

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

The layer arrangement is correspondingly wound on the first and second side walls guided by the first and the second side wall. The shape of the sidewalls essentially dictates the shape of the device.

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

Further advantageous embodiments will become apparent from the dependent claims.

• 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;
• Fig. 7 Dämpfung einer Schallquelle der Erfindung im Vergleich zum Stand der Technik.

Other objects, advantages and advantages of the present invention will become apparent from the following description when taken in conjunction with the drawings. Hereby show:

• 1A a side view of a device according to the invention with sound source;
• 1B another side view of the device;
• 2 a perspective view of the sound source with storage;
• 3 a front view of the 2 ;
• 4 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;
• Fig. 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 first side wall 6 so the sound source 2 can be seen. Behind the sound source 2 is the second sidewall 7 to recognize.

Next is a layer arrangement 3 the device 1 to recognize which in a circumferential direction 17 around the sound source 2 spirally wound and the sound source 2 thus encased. The layer arrangement 3 includes a first layer 4 and a second layer 5, wherein the first layer 4 without composite with the second layer 5 abuts the second layer 5.

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

The 1B shows as well a side view as the figure 1A, but here is the first side wall 6 to recognize. As can be seen further, the first side wall has 6 a first exit opening 18 a first air channel 14 (not shown here), which are in contact with the environment. Next is a recess 19 to recognize, by means of which it is possible, supply connections 20 (not shown here) to the sound source 2 to provide, for example, the sound source with energy or a required working medium.

The 2 shows the sound source 2 , which with the first side wall 6 as well as the second side wall 7 connected is. Exemplary is the storage 21 the sound source 2 with the second side wall 7 in the present case shown in more detail.

Again 2 , which is a perspective view of the device can be seen, is on a third end face 26 the second side wall a rib support member 25 arranged on the rib support element 25 , which is circular in shape, on its inner side inner ribs 24 and on its outside outer ribs 23 are arranged. The outer ribs 23 extend from the rib support member 25 straight in the direction of the second peripheral surface 13 the second side wall 7 , whereby an enlargement of the second peripheral surface 13 can be achieved. end regions 27 the outer ribs are formed to have the same shape as the adjacent thereto portion of the second peripheral surface 13 ,

To a swinging and dampening or springy storage 21 the sound source 2 opposite the second side wall 7 to reach are the inner ribs 24 made of a material which has certain damping or suspension properties, for example rubber or the like.

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

Next are the 2 second outlet openings 22 the air channels 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 openings 22 around is a cylindrical airflow limiting element 29 arranged, which with the respective side wall 6 . 7 connected is. The airflow limiting element 29 extends in the direction of the first or second normal vector 10 . 11 ,

The airflow limiting element 29 serves to avoid suction or Ausblaseffekten the second outlet openings 22 opposite the layer arrangement 3 because through the airflow limiting element 29 the air flow from or into the second outlet openings 22 is directed and so a direct effect on the layer arrangement 3 can be prevented. In addition, it is also conceivable that the air flow limiting element 29 can be used as a support for an airflow conveying element (not shown here), such as a fan, so that an airflow can be actively produced from the environment to the sound source and from the sound source to the environment.

The 3 shows the object of the 2 in a front view. From the 3 is also better again the operating principle of the air flow limiting elements 29 to recognize.

The 4 shows a similar structure as the 3 , 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 3 is recognizable.

Of the 4 Here is an exemplary embodiment of a first air duct 14 refer to. Towards the environment is a first outlet opening 18 , to the sound source 2 towards at least a second outlet opening 22 shown. The first outlet 18 goes into a first air duct part 31 over which is perpendicular in the direction 34 is arranged to extend to the normal vector 11. To the first air duct part 31 closes via a passage opening 30 a second air duct part 32 which is also perpendicular in the direction 35 to the normal vector 11 is arranged running. 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 provides the 5B the subject matter of the present invention. From the prior art, shown schematically by the figure 5A, basically closed mechanical profiles are known whose deformation is shown in the figure, whereby a significant increase in the rigidity is accompanied. In contrast to this, according to the invention, a device with a mechanically open profile can come up, which nevertheless is seamless from an acoustic point of view and has no or only a slight increase in rigidity.

This will be in the 5A and 5B In particular, be taken by the respective path amplitude at excitation of the encapsulation by a force with a force amplitude as drawn.

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

A comparison with the prior art is in particular the 7 refer to. An A weighting filter was applied to both frequency representations. In comparison with the prior art, a significantly improved reduction of the volume could be achieved by the device according to the invention.

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

LIST OF REFERENCE NUMBERS

1

contraption

2

sound source

3

layer arrangement

4

first shift

5

second layer

6

first sidewall

7

second side wall

8th

first end face

9

second end face

10

first normal vector

11

second normal vector

12

first peripheral surface

13

second peripheral surface

14

first air duct

15

second air duct

16

radial direction

17

circumferentially

18

first exit opening

19

recess

20

supply connection

21

storage

22

second exit opening

23

outer ribs

24

inner ribs

25

Ribs supporting element

26

third face

27

end

28

fourth face

29

Air flow restriction member

30

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 (10)

Device (1) for reducing noise emissions of a sound source (2), which is arranged in particular in and / or on a vehicle, characterized in that the device (1) comprises a layer arrangement (3) comprising a first layer (4) and a second layer (5), wherein the first layer (4) rests without composite with the second layer (5) on the second layer (5) and wherein the layer arrangement (3) spirally the sound source (2) in a circumferential direction (17 ) of the sound source (2) sheathed. Device (1) according to Claim 1 characterized in that the first layer (4) is made of a different material than the second layer (5), wherein the first layer (4) is at least partially made of an elastomer or bitumen and the second layer (5) is at least partially made of a softer one Material as the material of the first layer (4) exist. Device (1) according to Claim 1 or 2 , characterized in that the device (1) has at least one first side wall (6) with a first end face (8) and at least one second side wall (7) with a second end face (9), wherein a first normal vector (10) of the first End face (8) and a second normal vector (11) of the second end face (9) perpendicular to the circumferential direction (17). Device (1) according to Claim 3 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) being at least partially aligned with the first peripheral surface (12) first layer (4) are connected. Device (1) according to Claim 3 or 4 , characterized in that the first side wall (6) has a first air channel (14) and the second side wall (7) has a second air channel (15). Device (1) according to Claim 5 Characterized in that the first air duct (14) and the second air passage (15) in the direction of the corresponding normal vectors (10, 11) are formed in a meandering fashion. Device (1) according to one of Claims 3 to 6 , characterized in that the sound source (2) with the first side wall (6) and the second side wall (7) of the device (1) is connected. Device (1) according to one of Claims 3 to 7 , characterized in that the first end face (8) and the second end face (9) are formed substantially the same and have a circular, oval, elliptical or rectangular configuration and the normal vectors (10, 11) are parallel or identical to each other. 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 at least three times repetitive. Method for producing a device (1) for reducing noise emissions of 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 bonding between the first layer (4) and the second layer (5); b) attaching a first end (36) of the first layer (4) to a first sidewall (6) and a second sidewall (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), wherein the first layer (4) at least in operative contact with the first (6) and the second side wall (7) ; d) attaching a second end (37) of the first layer (4) to a partial surface of the first layer (4), which in a radial direction (16) of the sound source (2) below the second end (37) of the first layer ( 4) is arranged.

Images