EP3725090A1

EP3725090A1 - Bass reflex type loudspeaker enclosure

Info

Publication number: EP3725090A1
Application number: EP18814633.6A
Authority: EP
Inventors: Gilles Bourgoin
Original assignee: Sagemcom Broadband SAS
Current assignee: Sagemcom Broadband SAS
Priority date: 2017-12-19
Filing date: 2018-12-12
Publication date: 2020-10-21
Also published as: US11665468B2; WO2019121213A1; FR3075546B1; US20200322715A1; FR3075546A1; BR112020011557A2; CN111492665A

Abstract

Bass reflex type loudspeaker enclosure comprising a cabinet (6), a loudspeaker (7) and a first vent (10). The acoustic loudspeaker enclosure further comprises a second vent (11) and an internal heat sink (12) which is located inside the cabinet and intended to be thermally coupled to an electrical component (4) in order to dissipate, inside the cabinet, heat produced by the electrical component, the first vent, the second vent and the internal heat sink being positioned so that an air flow (F) which flows through the first vent, the second vent and into the cabinet moves the heat produced by the electrical component out of the cabinet.

Description

Acoustic speaker type bass reflex

The invention relates to the field of bass - reflex loudspeakers,

BACKGROUND OF THE INVENTION

Many modern electrical equipment includes an acoustic speaker for rendering an audio signal. Among these electrical equipment, there are in particular residential gateways, set-top boxes, televisions, voice assistants, etc.

An acoustic chamber equipping this type of electrical equipment conventionally comprises a box and a speaker attached to the box. The speaker outputs the audio signal by generating sound waves to the outside of the cabinet. The sound waves are produced by the speaker from an electrical current supplied to a speaker coil by an audio amplifier.

The performance of the loudspeaker at low frequencies can be improved by adding a vent to the casing. This is called a bass-reflex speaker. The air circulating in the vent between the interior of the chamber (at the rear of the speaker) and the outside space {at the front of the speaker) forms a mechanical system that resonates at a specific frequency. .

We are obviously looking to reduce the cost and the size of these electrical equipment.

OBJECT OF THE INVENTION

The invention aims to reduce the cost and bulk of an electrical equipment such as that just described.

SUMMARY OF THE INVENTION

In order to achieve this goal, a bass-reflex loudspeaker with a box, a loudspeaker and a first vent, characterized in that the acoustic chamber further comprises a second vent and an internal heat sink located inside the box and intended to be thermally coupled with an electrical component to dissipate to inside the box a heat produced by the electrical component, the first vent, the second vent and the internal heat sink being positioned so that a flow of air flowing through the first vent, the second vent and into the box discharges to the outside of the box the heat produced by the electrical component.

The internal heat sink is positioned inside the box. It therefore limits the total space required by the cooling function of the electrical component and by the sound reproduction function. This reduces the size of an electrical equipment incorporating the loudspeaker according to

The invention.

As a flow of air flows naturally through the case through the first vent and the second vent, it is not necessary to use a fan to improve cooling. This reduces the cost of electrical equipment incorporating the loudspeaker according to the invention.

In addition, an acoustic device is proposed comprising an acoustic chamber such as that just described, and an electrical board on which the electrical component is mounted.

In addition, electrical equipment is proposed comprising an acoustic device such as the one just described.

Other characteristics and advantages of the invention will emerge on reading the description following of particular embodiments, not limiting of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

Reference will be made to the appended drawings among which:

FIG. 1 represents an acoustic enclosure according to a first embodiment of the invention;

FIG. 2 represents an acoustic enclosure according to a second embodiment of the invention;

FIG. 3 represents an acoustic enclosure according to a third embodiment of the invention;

FIG. 4 represents an acoustic enclosure according to a fourth embodiment of the invention;

FIG. 5 represents an acoustic enclosure according to a fifth embodiment of the invention;

FIG. 6 represents an acoustic enclosure according to a sixth embodiment of the invention;

FIG. 7 represents an acoustic enclosure according to a seventh embodiment of the invention;

FIG. 8 represents an internal heat sink of the acoustic enclosure according to the seventh embodiment of the invention,

FIG. 9 represents an acoustic enclosure according to an eighth embodiment of the invention

DETAILED DESCRIPTION OF THE INVENTION

With reference to FIG. 1, the invention is implemented here in a residential gateway 1.

The residential gateway 1 comprises an electrical card 2 comprising a plurality of electrical components 3 belonging to an audio amplifier (that is to say that the electrical components 3 contribute to implement an audio amplifier function). The audio amplifier produces an electrical current used to reproduce an audio signal.

The electrical component 4 is, among the components Electric 3, the electrical component that generates the most heat.

The residential gateway 1 further comprises an acoustic enclosure according to a first embodiment of the invention 5.

The acoustic enclosure 5 comprises a box 6 defining an internal cavity of defined volume, and a loudspeaker 7. The loudspeaker 7 is located on a first face 8 of the box 6, which is here a front face of the box 6.

The speaker 7 comprises a coil. The electrical current produced by the audio amplifier flows in the speaker coil 7 so that the speaker 7 generates sound waves and thus restores the audio signal.

The acoustic enclosure 5 further comprises a first vent 10 and a second vent 11.

The first vent 10 is located near a first end of the first face 8. The first end is an upper end. The second vent

11 is located near a second end of the first face 8. The second end is a lower end. By "near" is meant that a maximum distance between a vent and an end of the face is less than one third of the total length of the face.

The first vent 10 extends from the first face 8, horizontally, inside the box 6. The second vent 11 extends from the first face 8, horizontally, inside the box 6.

Of course, the terms "upper", "lower", "horizontal" and "vertically" are to be interpreted in a configuration where the loudspeaker 5 is positioned in a nominal position of use. The loudspeaker 7 is here positioned between the first vent 10 and the second vent 11,

The first vent 10 and the second vent 11 are positioned and dimensioned to allow natural air circulation in the acoustic enclosure 5, so that a flow of air F flows naturally through the second vent 11, in the box 6, and through the first vent 10. The direction of the air flow F may of course be different from that shown in Figure 1.

The first vent 10 and the second vent 11 are also positioned and sized to optimize the acoustic performance of the acoustic enclosure 5, especially in the low frequencies.

The sizing of the first vent 10 and the second vent 11, both of the "bass-reflex" type, is obtained by using, for each vent, the definition of a Helmholtz resonator.

We have, for each vent:

{A / 2) ² = (L + k.0). V / S,

where l is the wavelength of the resonance frequency of the vent, L is the length of the vent, 0 is the diameter of the vent, V is the defined volume of the internal cavity of the well 6, S is the section of the vent. The coefficient k is a coefficient representative of the state of discontinuity of the ends of the vent. The coefficient k tends to 0.5 if the endings of the vent are flared. The coefficient k tends to 1 if the endings of the vent are flush.

We also have :

X = C / F, where F is the wavelength of the resonance frequency and c is the speed of sound.

For example, to have a "bass reflex" resonator at 100 Hz in a loudspeaker 5 having a defined volume of 3 liters, it is possible to sizing the first vent 10 and the second vent 11 so that they each have a diameter of 4 cm and a length of 13 cm.

The acoustic enclosure 5 further comprises an internal heat sink 12, in this case a finned heat sink. The internal heat sink 12 comprises a base 13 and a plurality of fins 14 extending from the base 13 perpendicular to the base 13.

When the internal heat sink 12 is mounted in the box 6, the internal heat sink 12 extends near a second face 15 of the box 6 located opposite the first face 8. The second face 15 is here a face back of the casing 6.

The base 13 of the internal heat sink 12 extends in parallel and is fixed to an inner wall of the second face 15. By "wall" is meant here a side of a face. The fins 14 of the internal heat sink 12 then extend towards the inside of the box 6.

The electrical card 2 of the residential gateway 1 is located outside the box 6 of the acoustic enclosure 5. The electrical card 2 is positioned parallel to an outer wall of the second face 15 of the box 6 of the acoustic enclosure 5 .

The base 13 of the internal heat sink 12 is thermally coupled to the electrical component 4 of the electrical board 2.

To achieve the thermal coupling, the internal heat sink 12 comprises a metal pin 17 which extends from the base 13 of the internal heat sink 12 on the opposite side to the fins 14. When the internal heat sink 12 is mounted in the box 6, the metal pin 17 extends through the second face 15 of the box 6. When the enclosure Acoustic 5 and the electrical card 2 are integrated in the residential gateway 1, the electrical component 4 is in contact with the metal pin 17. The thermal coupling is here a direct contact.

Thus, the heat produced by the electrical component 4 is dissipated by the internal heat sink 12 inside the box 6. The air flow F, which also flows along the internal heat sink 12 and on the fins 14 of the dissipator internal thermal 12, discharges to the outside of the box 6 the heat produced by the electrical component 4.

With reference to FIG. 2, an acoustic enclosure according to a second embodiment of the invention 105 includes a fan 120. The fan 120 is positioned outside the acoustic enclosure 105, at an inlet of the second Vent 111. The fan 120 extends opposite the inlet of the second vent 111. By "inlet" is meant here the orifice of a vent which opens out of the box 106, and "output" here is meant the orifice of a vent which opens inside the box 106.

The fan 120 is an axial fan with a propeller. The static pressure of the fan 120 is relatively small, and is for example less than 2GPa or 30Pa. The fan can thus be mounted directly to the inlet of the second vent 111, and could also be mounted at an outlet of the second vent 111, or inside the second vent 111.

It is possible to choose another type of fan, and in particular a turbine fan with a higher static pressure, for example of the order of 10 Pa or 150 Pa. In this case, the fan 120 will have to be separated from the second vent 111 by a few millimeters, for example from 5 to 10 mm, so as not to disturb the performance of the second vent 111 while ensuring its air mixing function.

The choice of the fan 120 is based on acoustic criteria. The fan 120 is quiet and balanced. The fan 120 does not generate vibrations in the structure of the acoustic enclosure 105, and does not disturb the primary function of the acoustic chamber 105, which is to reproduce an audio signal.

The fan 120 is mounted via a damping device integrated in the fan 120 and located between the fan body 120 and the box 106. This flexible assembly limits the transmission of residual vibrations produced by the fan 120. The fan 120 could also be mounted rigid by taking certain precautions to avoid the transmission of vibrations.

The sizing of the second vent 111 must of course be compatible with the dimensions of the fan 120. The diameter of the fan 120 is here greater than that of the second vent 111.

The fan 120 makes it possible to improve the thermal performance of the acoustic enclosure 105. The fan 120 forces the air circulation through the second vent 111, into the well 106 and through the first vent 110, as well as along the internal heat sink 112. The air flow F is more important and the heat produced by the electrical component 104 is discharged to the outside of the chamber 106 of the acoustic enclosure 105 more effectively.

It is noted that the low overpressure generated by this ventilation can be likened to a negligible continuous load for the loudspeaker 107 and for the first vent 110 and the second vent 111. The operation of the loudspeaker 107, the first vent 110 and the second vent 111 is not challenged by this continuous load,

It should be noted that the fan 120 could also be mounted at the inlet, at the outlet or inside the first vent 110,

With reference to FIG. 3, an acoustic enclosure according to a third embodiment of the invention 205 comprises a fan 220. The fan 220 is positioned inside the acoustic enclosure 205, at an outlet of the second vent 211. The diameter of the fan 220 is close to that of the second vent 211 (but it could be higher or lower),

With reference to FIG. 4, an acoustic enclosure according to a fourth embodiment of the invention 305 includes a first fan 320 and a second fan 321. The first fan 320 is positioned inside the acoustic enclosure 305, at the level of an output of the first vent 310. The second fan 321 is positioned inside the acoustic chamber 305, at an outlet of the second vent 311.

With reference to FIG. 5, it is noted that it is possible to position the electrical card 402 inside the box 406 of an acoustic enclosure according to a fifth embodiment of the invention 405.

The electrical board 402 extends parallel and is fixed to the inner wall of the second face 415 (rear face). The base 413 of the internal heat sink 412 extends parallel to the inner wall of the second face 415. The electrical card 402 is positioned between the base 413 of the internal heat sink 412 and the inner wall of the second face 415. The metal pin 417 is in contact with the electrical component 404. This configuration further improves the integration of the acoustic enclosure 405 including the internal heat sink 412 and the electrical board 402, and reduces the total volume required by the acoustic enclosure 405 including the internal heat sink 412 and the electrical card 402 ,

Of course, it would be possible to add to the loudspeaker 405 one or more fans positioned as has been described earlier,

With reference to FIG. 6, the internal heat sink 512 of an acoustic enclosure according to a sixth embodiment of the invention 505 is integrated with the structure of the acoustic enclosure 505.

A flat surface of the internal heat sink 512 forms at least a portion of an outer wall of a face of the box 506. Here, in this case, this flat surface is a surface of the base 513 of the internal heat sink 512. base 513 forms the whole of the second face 515 (rear face) of the box 506 of the loudspeaker 505.

The electrical card 502 then extends outside the box 506 of the acoustic chamber 505, parallel to the second face 515 of the box 506. The metal pin 517 of the internal heat sink 512 is in contact with the electrical component 504.

The base 513 of the internal heat sink 512 and the rear face of the box 506 are thus combined. Thus, the mass and the overall cost of the loudspeaker 505, which fulfills the function of restitution of the audio signal and heat dissipation, and therefore the mass and the cost of the residential gateway in which the loudspeaker 505 is integrated, are reduced. .

With reference to FIGS. 7 and 8, the internal heat sink 612 is again integrated with the structure of the acoustic enclosure according to a seventh mode Embodiment of the Invention 605. The base 613 of the internal heat sink 612 again forms the entire second face 615 (rear face) of the box 606 of the loudspeaker 605.

The first vent 610 and the second vent 611 are integrated with the internal heat sink 612. The first vent 610 and the second vent 611 therefore extend inside the well 606 from the second face 615 of the well 606.

The first vent 610 and the second vent 611 are each constituted by a cylinder which extends at least partially into the internal heat sink 612. The cylinder forming the first vent 610 extends between the two fins 614a, 614b. The cylinder forming the second vent 611 extends between the two fins 614c, 614d. An axis of each cylinder is perpendicular to the base 613 of the internal heat sink 612 and parallel to the planes in which the fins 614 extend. Note that the cylinders extend between two pairs of different fins, which is a possibility but not an obligation. It would thus be possible for example that the axis of a vent corresponds to that of a fin.

The first vent 610, the second vent 611 and the internal heat sink 612 form here a single piece. The single piece may for example be manufactured wholly or partially of metal or thermal plastic, for example polyamide.

With reference to FIG. 9, a housing of a residential gateway 701 comprises an acoustic enclosure according to an eighth embodiment of the invention 705. The acoustic enclosure 705 comprises an internal heat sink 712. The residential gateway 701 further comprises an external heat sink 722 positioned outside of the acoustic enclosure 705.

The internal heat sink 712 and the external heat sink 722 are both finned heat sinks, similar to those already described.

The internal heat sink 712 is positioned inside the box 706. The base 713 of the internal heat sink 712 is mounted against the inner wall of the second face 715 of the box 706. The electrical board 702 extends parallel to the outer wall of the second face 715 (rear face) of the box 706, outside the box 706.

The external heat sink 722 is positioned outside the casing 706. A base 723 of the external heat sink 722 extends parallel to the outer wall of the second face 715 of the casing 706. The fins 724 of the external heat sink 722 extend from the base 723, perpendicular to the base 723, to a face 725 of the housing of the residential gateway 701 located opposite the first face 708 (front face) of the acoustic enclosure 705 (and the residential gateway 701). ).

The external heat sink 722 is also thermally coupled with the electrical component 704. The external heat sink 722 has for this purpose a metal pin 727 which comes into contact with the electrical component 704. The metal pin 717 of the internal heat sink 712, as for him, comes into contact with a surface of the printed circuit of the electrical card 702 extending under the electrical component 704.

Note that the first vent 710 is again located near the first end of the first face 708, and the second vent 711 is again located near the second end of the first face 708.

This time, however, the first vent 710 extends vertically inside the casing, from a third face 730. The third face is an upper face of the casing 706.

Similarly, the second vent 711 extends vertically inside the box, from a fourth face 731. The fourth face is a lower face of the box 706.

Of course, the invention is not limited to the embodiments described, but encompasses any variant within the scope of the invention as defined by the claims.

It has been described here that the thermal coupling between each heat sink and an electrical component is a direct contact via a metal pin. The thermal coupling could be an indirect coupling, for example a coupling via a thermally conductive, possibly elastic, component.

Although it has been described here that the first vent and the second vent extend inside the casing, one or both of the vents could well extend out of the casing, or partially into the casing. inside and partially outside the box.

It is also possible that only one of the two vents will extend horizontally, and only one of the two vents will extend vertically.

It has been indicated that the internal heat sink and the external heat sink are arranged to cool the same electrical component. Of course, the internal heat sink can perfectly cool a first electrical component and the external heat sink a second electrical component. The second electrical component may for example be located on the same electrical card but on another face, or on another electrical card. The internal heat sink (and / or external) can of course cool not one but several electrical components. The electrical component (s) thermally coupled with the internal (and / or external) heat sink do not necessarily belong to an audio amplifier; it can be any type of electrical component heating up in operation, for example a processor, a radio transmitter, etc.

The first vent may be located on any face of the caisson. Preferably, the end of the first vent is located at the top to evacuate the hot air. Similarly, the second vent may be located on any face of the box. Preferably, the end of the second vent is located in the lower part to allow the entry of fresh air.

It has been indicated that the first vent is located near a first end of the first face, the second vent is located near a second end of the first face, and the first end is an upper end and the second end a lower end. One could imagine a different configuration. Thus, for example, if the first face comprising the loudspeaker is an upper face, the first end could be a left end and the second end be a right end of the first face.

Claims

1. A bass-reflex acoustic enclosure comprising a housing (6; 106), a speaker (7;

107) and a first vent (10; 110), characterized in that the acoustic chamber further comprises a second vent (11; 111) and an internal heat sink (12; 112) located inside the casing and for to be thermally coupled with a first electrical component (4; 104) to dissipate inside the box a heat produced by the first electrical component, the first vent, the second vent and the internal heat sink being positioned so that a air flow (F) flowing through the first vent, the second vent and into the box discharges to the outside of the box the heat produced by the first electrical component.

2. An acoustic chamber according to claim 1, the loudspeaker (7; 107) being located on a first face (8) of the box, the first vent (10; 110) being located near a first end of the first face (8), the second vent (11; 111) being located near a second end of the first face (8), and the internal heat sink extending near a second face (15) of the housing located next to the first side.

3. acoustic chamber according to claim 1, wherein the first vent and / or the second vent extend horizontally inside the box.

4. acoustic chamber according to claim 1, wherein the first vent (710) and / or the second vent (711) extend vertically inside the box.

5. acoustic chamber according to claim 1, further comprising at least one fan (120) positioned at an inlet or an outlet of the first vent or the second vent.

The acoustic chamber of claim 1, wherein a planar surface of the internal heat sink (512; 612) forms a portion of an outer wall of a face of the box.

7. The acoustic chamber of claim 6, wherein the first vent and / or the second vent extend at least partially into the internal heat sink.

The acoustic chamber of claim 7, wherein the first vent (610), the second vent (611), and the internal heat sink (612) form a single piece.

9. The acoustic chamber according to claim 7, wherein the internal heat sink (612) is a finned heat sink, and wherein the first vent and the second vent each extend between two fins (614) of the internal heat sink.

10. Acoustic device comprising an acoustic enclosure according to one of the preceding claims, and an electrical card (2; 102) on which is mounted the first electrical component.

11. Acoustic device according to claim

10, wherein the electrical card is located inside the box.

12. Acoustic device according to claim

10, wherein the electrical card is located outside the box.

13. Acoustic device according to claim

10, wherein the first electrical component belongs to an audio amplifier.

14. Acoustic device according to claim

10, further comprising an external heat sink (722) positioned outside the loudspeaker.

15. Acoustic device according to claim

14, the external heat sink being thermally coupled with a second electrical component.

16. Acoustic device according to claim

15, the second electrical component and the first electrical component being the same electrical component.

17. Electrical equipment comprising an acoustic device according to one of claims 10 to 16.

18. Electrical equipment according to claim

17, the electrical equipment being a residential gateway or a set-top box or a television or a voice assistant.