Classifications

• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
  • H04R1/00—Details of transducers, loudspeakers or microphones
  • H04R1/20—Arrangements for obtaining desired frequency or directional characteristics
  • H04R1/22—Arrangements for obtaining desired frequency or directional characteristics for obtaining desired frequency characteristic only 
  • H04R1/28—Transducer mountings or enclosures modified by provision of mechanical or acoustic impedances, e.g. resonator, damping means
  • H04R1/2803—Transducer mountings or enclosures modified by provision of mechanical or acoustic impedances, e.g. resonator, damping means for loudspeaker transducers
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
  • H04R1/00—Details of transducers, loudspeakers or microphones
  • H04R1/20—Arrangements for obtaining desired frequency or directional characteristics
  • H04R1/22—Arrangements for obtaining desired frequency or directional characteristics for obtaining desired frequency characteristic only 
  • H04R1/28—Transducer mountings or enclosures modified by provision of mechanical or acoustic impedances, e.g. resonator, damping means
  • H04R1/2869—Reduction of undesired resonances, i.e. standing waves within enclosure, or of undesired vibrations, i.e. of the enclosure itself
  • H04R1/2892—Mountings or supports for transducers
  • H04R1/2896—Mountings or supports for transducers for loudspeaker transducers
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
  • H04R1/00—Details of transducers, loudspeakers or microphones
  • H04R1/02—Casings; Cabinets ; Supports therefor; Mountings therein
  • H04R1/025—Arrangements for fixing loudspeaker transducers, e.g. in a box, furniture
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
  • H04R1/00—Details of transducers, loudspeakers or microphones
  • H04R1/20—Arrangements for obtaining desired frequency or directional characteristics
  • H04R1/22—Arrangements for obtaining desired frequency or directional characteristics for obtaining desired frequency characteristic only 
  • H04R1/28—Transducer mountings or enclosures modified by provision of mechanical or acoustic impedances, e.g. resonator, damping means
  • H04R1/2869—Reduction of undesired resonances, i.e. standing waves within enclosure, or of undesired vibrations, i.e. of the enclosure itself
  • H04R1/2873—Reduction of undesired resonances, i.e. standing waves within enclosure, or of undesired vibrations, i.e. of the enclosure itself for loudspeaker transducers

Definitions

• the invention relates to the field of stiffening parts for an acoustic enclosure.
• An acoustic enclosure comprises a box and one or more speakers.
• One or more faces of the box include one or more openings each intended to accommodate a speaker.
• the movement of the loudspeaker membranes is the source of vibrations which produce unwanted noise.
• an enclosure of the prior art 1 comprises a box 2 having an upper face, a lower face and lateral faces.
• the enclosure further comprises a first speaker 3a mounted on the upper face and a second speaker 3b mounted on the underside of the box 2.
• the operation of the speakers 3 excites three modes of vibration of the enclosure 1 .
• a first vibration mode results from a pumping movement of the magnets 4 of the loudspeakers 3.
• the magnet 4 of each loudspeaker 3 undergoes a translational movement along the translation axis XI (see FIG. 1) which is a longitudinal axis of the enclosure 1.
• This translational movement is due to the relatively large mass of the magnet 4 and to the relative flexibility of the sheet 5 of the loudspeaker 3 called “salad bowl", in which the membrane (not shown).
• the translational movement occurs in the operating direction of the diaphragm of the speaker 3.
• a second mode of vibration results from a pendulum movement of the magnets 4 of the loudspeakers 3.
• the magnet 4 of each loudspeaker 3 undergoes a rotational movement around a pendulum axis X2 which passes through the center of the membrane and which is perpendicular to the longitudinal axis of the speaker 3 (see Figure 2).
• This rotational movement is also due to the relatively large mass of the magnet 4 and the relative flexibility of the sheet metal of the loudspeaker 3.
• a third mode of vibration results from a deformation of the box 2 of the enclosure 1, which "swells" due to the increase in internal pressure induced by the displacement of the membranes of the speakers 3.
• the object of the invention is to reduce the vibrations and therefore the parasitic noise of an acoustic enclosure.
• a stiffening piece which is designed to be integrated inside a box of an acoustic enclosure in order to stiffen said box, the acoustic enclosure possibly further comprising at least one loudspeaker.
• speaker mounted on a first face of the box, the stiffening part comprising a connecting portion, at least one damping support defining a reception space arranged to receive a damping device intended to limit vibrations of the loudspeaker, the damping support comprising a plurality of ribs distributed around the reception space, each rib extending in a separate plane parallel to a depth of the reception space, the stiffening part being arranged so that , when the enclosure is assembled, the connecting portion interconnects internal walls of a second face of the box and a third face of the box opposite to each other and all of them perpendicular to the first face, the damping device is positioned in the reception space, and a rear part of the loudspeaker comes to bear against the damping device.
• the connecting portion which connects the second face and the third face of the box, the ribs and the damping device positioned in the reception space make it possible to limit the vibrations which have just been mentioned. Thanks to the stiffening part according to the invention, the three main resonant frequencies of the enclosure are moved outside the range of use of the loudspeaker, and the parasitic noise is reduced very significantly.
• An enclosure comprising a box, a loudspeaker, the stiffening part which has just been described, and a damping device.
• Figure 1 is a perspective view of a box and two speakers of an enclosure according to the prior art, the view being cut in a plane parallel to a longitudinal axis of the enclosure;
• Figure 2 is a view similar to that of Figure 1, one of the two speakers undergoing a pendulum movement;
• Figure 3 is a perspective view of an enclosure comprising a box, two speakers, two damping devices, and a stiffening part according to the invention
• Figure 4 is a view similar to that of Figure 3, the view being cut in a plane parallel to a longitudinal axis of the enclosure;
• Figure 5 is a perspective view of the stiffening part according to the invention.
• Figure 6 is a perspective view of a damping device.
• the invention is here implemented in an acoustic enclosure 11 which is in this case a connected enclosure.
• the enclosure 11 firstly comprises a box 12 and a plurality of speakers.
• the box 12 has a generally parallelepiped exterior shape.
• the box 12 comprises an upper face, here called first face 14, four side faces, among which there are two opposite faces (that is to say located one opposite the other) called here second face 15 and third face 16, and a lower face, here called fourth face 17.
• first face 14 and the fourth face 17 are two opposite faces which are both perpendicular to the second face 15 and to the third face 16.
• the axis X3 which passes through the center of the first face 14 and the fourth face 17 is called here "longitudinal axis of the box".
• the plurality of speakers includes a first speaker 18a and a second speaker 18b, as well as other speakers which will not be described here.
• the first loudspeaker 18a and the second loudspeaker 18b here each comprise a membrane 19, a sheet 20 called a "bowl” in which the membrane 19 extends, a coil and a magnet 21.
• Each magnet 21 has here a shape frusto-conical, the radius of which decreases towards the rear of the loudspeaker 18.
• the term “front part” of each loudspeaker 18 is used here to refer to the part which comprises the membrane 19, and “rear part” to the side part opposite the membrane 19. The rear part therefore here comprises the magnet 21.
• longitudinal axis of the loudspeaker X4 is the axis of revolution of the magnet 21, which also passes through the center of the membrane 19 , and the height of the loudspeaker 18 is called “height” of the loudspeaker 18 along its longitudinal axis X4.
• the first speaker 18a is mounted on the first face 14 of the box 12.
• the first speaker 18a is fixed to the first face 14, the longitudinal axis X4 of the first speaker 18a being perpendicular to the first face 14.
• the first face 14 has an opening whose shape coincides with the circumference of the large diameter of the membrane 19 of the first loudspeaker 18a and into which the membrane 19 opens.
• the second loudspeaker 18b is mounted in the same way on the fourth face 17 of the box 12.
• the first loudspeaker 18a and the second loudspeaker 18b are therefore mounted head to tail in the casing 12, and their longitudinal axes X4 are merged.
• the longitudinal axes X4 of the first loudspeaker 18a and of the second loudspeaker 18b are parallel with the longitudinal axis X3 of the box 12.
• the enclosure also comprises a stiffening part 25 integrated inside the box 12.
• the stiffening part 25 is positioned between the first loudspeaker 18a and the second loudspeaker 18b,
• the stiffening part 25 is made of a thermoplastic material.
• the stiffening part 25 firstly comprises a connecting portion 26 (which could also be called “beam”).
• the connecting portion 26 interconnects the internal wall of the second face 15 and the internal wall of the third face 16.
• the connecting portion 26 extends in length along a connecting axis X5 which, when the stiffening piece 25 is positioned in the box 12, is parallel to a transverse axis of the box 12 and is orthogonal to 1 axis longitudinal X3 of the box 12.
• the connecting portion therefore extends parallel to the first face 14 and to the fourth face 17 of the box 12.
• connection portion 26 here comprises a first end 27 and a second end 28 each provided with means for fixing to one face of the box 12, in this case here a thread 29.
• the first end 27 of the connection portion 26 is fixed by screwing to the second face 15 of the box 12, while the second end 28 of the connecting portion 26 is fixed by screwing to the third face 16 of the box 12.
• a first screw 38 (visible in FIG. 4) s 'thus extends through the second face 15 to be screwed into the thread 29 of the first end 27, and a second screw 38 extends through the third face 16 to be screwed into the thread 29 of the second end 28 of the connecting portion 26.
• the stiffening part 25 further comprises a first damping support 30a and a second damping support 30b.
• the first damping support 30a and the second damping support 30b are located at a central part of the connecting portion 26.
• the first damping support 30a defines a reception space 31 having a general shape of revolution, in this case a frustoconical shape.
• the axis of revolution X6 of the reception space 31 is orthogonal to the connection axis X5 of the connection portion 26.
• the radius of the reception space 31 is reduced to the level a bottom 32 of the reception space 31, and increases until the main opening of the reception space 31, which extends opposite the bottom 32 of the reception space 31.
• the first damping support 30a comprises ribs 34 which are distributed, with a different orientation, around the reception space 31.
• the ribs 34 each have the shape of a fin.
• the ribs 34 extend radially around the reception space 31 from the circumference of the reception space 31.
• the length of each rib is parallel to the axis of revolution X6 of the reception space 31
• the width of each rib 34 is defined in the extension of the radius of the reception space 31.
• Each rib 34 extends in a distinct plane parallel to a depth of the reception space 31, this is i.e. here at the axis of revolution X6 of the reception space 31.
• Each rib 34 comprises a base 35, located at the bottom 32 of the reception space 31, and a free end 36.
• Each rib 34 has a notch 37 formed opposite the reception space 31, so that the width of each rib 34 decreases from the base 35 of the rib 34 to the free end 36 of the rib 34.
• the frustoconical shape of the reception space 31 is defined by the notches 37 formed in the ribs 34.
• the second damping support 30b has the same shape as the first damping support 30a.
• the reception space 31 of the first damping support 30a and that of the second damping support 30b have an axis of revolution X6 combined, so that, looking along this axis of revolution X6, the first damping support 30a and the second damping support 30b are superimposed.
• the ribs 34 of the first damping support 30a are defined in the continuity and in the extension of the ribs 34 of the second damping support 30b: these are the same ribs 34 which each comprise a half of rib belonging to the first damping support 30a and a half of rib belonging to the second damping support 30b.
• first damping support 30a and the second damping support 30b are however arranged head to tail, on either side of the connecting axis X5 of the connecting portion 26: the bottom 32 of the space d reception 31 of the first damping support 30a is situated against or at least close to the bottom of the reception space 31 of the second damping support 30b,
• the reception space 31 of the first damping support 30a is intended to accommodate a damping device 40a
• the reception space 31 of the second damping support 30b is intended to accommodate a damping device 40b .
• Each damping device 40 is made of a flexible material, here an elastomeric material.
• each damping device 40 has a frustoconical external shape, and has a relatively small thickness.
• the large radius face 41 of the damping device 40 is completely open, while the small radius face 42 of the damping device 40 is partially closed while having a central opening 43.
• the central opening 43 allows suction and the evacuation of the air masses displaced by the movement of the membrane 19.
• the assembly of the enclosure 11 is carried out as follows.
• the stiffening part 25 is screwed into the box 12.
• a damping device 40a is arranged in the reception space 31 of the first damping support 30a.
• a damping device 40b is arranged in the reception space 31 of the second support amortization 30b.
• the first speaker 18a is fixed to the first face 14 of the box 12 and the second speaker 18b is fixed to the fourth face 17 of the box 12. Then, the first speaker 18a, the first face 14, the second speaker 18b and 1a fourth face 17 are mounted on the rest of the box 12.
• connection portion 26 of the stiffening piece 25 connects the internal walls of the second face 15 of the box 12 and of the third face 16 of the box 12.
• the rear part of the first top speaker 18a bears against the damping device 40a positioned in the reception space 31 of the first damping support 30a.
• the rear part of the second loudspeaker 18b bears against the damping device 40b positioned in the reception space 31 of the second damping support 30b.
• the ribs 34 of the first damping support 30a and the ribs 34 of the second damping support 30b are all perpendicular to the first face 14 and to the fourth face 17 of the box 12, and are all parallel to the longitudinal axis X3 of the box 12.
• the stiffening part 25 is structured by the ribs 34 which also stiffen the box 12.
• the ribs 34 prevent deformation by swelling of the box 12 caused by variations in internal pressure due to the displacement of the membranes 19 of the first loudspeaker 18a and of the second speaker 18b.
• the damping devices 40 significantly limit the pumping of the magnets 21 of the first loudspeaker 18a and of the second loudspeaker 18b, that is to say the translational movement of the magnets 21.
• the damping devices 40 also significantly limit the balance of the magnets 21 around the balance axis X2.
• the use of the stiffening part 25 thus makes it possible to move the three main resonant frequencies of the enclosure 11 outside the range of use of the first loudspeaker 18a and the second loudspeaker 18b (and the other loudspeakers -speakers of the enclosure 11), that is to say here beyond 300Hz.
• the stiffening part 25 therefore makes it possible, with a simple assembly of a plastic part and two elastomer washers, to eliminate the sources of vibration of the enclosure 11 causing the parasitic noises.
• the stiffening part 25 comprises a plurality of card supports 43.
• Each card support 43 comprises a flat surface 44 of rectangular shape and four corners 45.
• first card support 43a located at the first end 27 of the connection portion 26 and a second card support 43b located at the second end 28 of the connection portion 26.
• planar surface 44 of the first card support 43a is parallel to the second face 15 of the box 12 and is located opposite and near the second face 15.
• planar surface 44 of the second card support 43b is parallel to the third face 16 of the box 12 and is located opposite and near the third face 16.
• the first card holder 43a is arranged to receive a first electric card 46a, which is positioned against the flat surface 44 of the first card holder 43a while being held in position between the four corners 45.
• the first electric card is fixed to the first card holder 43a.
• the first electric card 46a here includes a Wi-Fi antenna which does not interact with the speakers.
• the second card holder 43b is arranged to receive a second electric card 46b, which is positioned against the flat surface 44 of the second card holder 43b while being held in position between the four corners 45.
• the second electric card 46b is fixed to the second card holder 43b.
• the second electric card 46b here includes a Wi-Fi antenna which does not interact with the speakers.
• Grooves 48 are formed on the damping supports 30 of the stiffening part 25. Electrical wires connected to the first electrical card 46a and to the second electrical card 46b pass through the grooves 48. The grooves 48 allow both hold in position and protect these electrical wires.
• the stiffening piece 26 makes it possible to integrate and protect, cleverly and inexpensively, electric cards 46 and wires inside the box 12.
• the loudspeaker (s) which cooperate with the stiffening part are not necessarily mounted on an upper face or on a lower face of the box.
• each built-in speaker could have a different shape (annular, cylindrical, etc.), just like the reception space of each support.
• the rear part of the loudspeaker which is in contact with the damping device, is not necessarily the magnet, but may be any element located at the rear of the loudspeaker: part of the motor, part integral with the salad bowl, etc.
• the damping device (s) may be different from those described here.
• the damping devices could be integrated into the stiffening part, for example by being produced by overmolding.
• the stiffening piece could belong to the box and form a single piece with the box (or at least with the second face and / or the third face of the box).
• the connecting portion connects the internal walls of the second face of the box and of the third face of the box, it does not necessarily mean that the connecting portion is directly fixed on the internal walls: the connecting portion could be fixed on any parts which are themselves integral with the internal walls.

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• Physics & Mathematics (AREA)
• Engineering & Computer Science (AREA)
• Acoustics & Sound (AREA)
• Signal Processing (AREA)
• Health & Medical Sciences (AREA)
• Otolaryngology (AREA)
• Details Of Audible-Bandwidth Transducers (AREA)
• Audible-Bandwidth Dynamoelectric Transducers Other Than Pickups (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=66166194

Family Applications (1)

Country Status (6)

Family Cites Families (13)

• 2018
  • 2018-12-03 FR FR1872244A patent/FR3089380B1/fr active Active
• 2019
  • 2019-11-14 EP EP19802179.2A patent/EP3892010A1/de active Pending
  • 2019-11-14 US US17/295,552 patent/US11245979B1/en active Active
  • 2019-11-14 WO PCT/EP2019/081406 patent/WO2020114750A1/fr unknown
  • 2019-11-14 CN CN201980079733.XA patent/CN113170258A/zh active Pending
  • 2019-11-14 BR BR112021009754-6A patent/BR112021009754A2/pt unknown

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