Loudspeaker system for vehicle

Abstract

A loudspeaker system for vehicle has a wall of a frame of a vehicle that separates an exterior from an interior and has a through hole, a box mounted in the wall in correspondence of the through hole, a loudspeaker mounted in the box, a back resonance chamber formed between the membrane of the loudspeaker and the walls of the box, a through hole obtained in a wall of the box and disposed in register with the hole of the wall of the frame of the vehicle and a partition of sound-absorbing material that closes the through hole of the wall of the box.

Claims

1. Loudspeaker system for vehicle comprising: a wall of a frame of a vehicle that separates an exterior from an interior; said wall having a through hole, a box mounted in the wall in correspondence of the through hole of the wall and facing inwards, a loudspeaker mounted in the box; said loudspeaker comprising a basket fixed to the box, a magnetic unit fixed to the basket, a coil supported by a cylinder connected to a membrane and centering devices that connect the cylinder to the basket and the membrane to the basket, a back resonance chamber formed between said membrane of the loudspeaker and the walls of the box, a through hole obtained in a wall of the box and disposed in register with said hole of the wall of the frame of the vehicle; said through hole of the wall of the box being in communication with said back resonance chamber, and characterized in that said basket and said magnetic unit are disposed inside a box, in said back resonance chamber, said basket is open and is provided with openings intended to let air pass in said back resonance chamber, a partition of sound-absorbing material is provided and fills said through hole of the wall of the box.

2. The system of claim 1, wherein said partition is made of an agglomerate of natural fibers, synthetic fibers and/or open-cell foams.

3. The system of claim 1, wherein said membrane of the loudspeaker has a truncated-conical shape and defines a front truncated-conical volume, wherein the volume of said back resonance chamber is higher than said front volume.

4. The system of claim 1, wherein said basket of the loudspeaker is fixed to a front wall of the box; and said through hole of the box is obtained in a back wall of the box.

5. The system of claim 4, wherein said through hole of the back wall of the box has an axis that coincides with the axis (Y) of the loudspeaker.

6. The system of claim 1, wherein said basket of the loudspeaker is fixed to a front wall (21) of the box; said through hole of the box is obtained in a lateral wall of the box; said through hole of the wall of the box has an axis (X) orthogonal to the axis (Y) of the loudspeaker.

7. The system of claim 1, wherein said basket of the loudspeaker is fixed to a front wall of the box; and said through hole of the box is obtained in said front wall of the box.

8. The system of claim 1, comprising a connection pipe or duct that externally protrudes from the wall of the box, around the hole that receives the partition for fixing to the wall of the frame.

Description

(1) Additional features of the invention will appear clearer from the detailed description below, which refers to merely illustrative, not limiting embodiments, wherein:

(2) FIG. 1 is a sectional view of the loudspeaker system for vehicle according to the invention;

(3) FIG. 2 is a partially cut and interrupted side view of a vehicle and of the loudspeaker system of FIG. 1 installed in an upper part of a trunk of the vehicle;

(4) FIG. 3 is a partially cut rear view of the vehicle of FIG. 2;

(5) FIG. 4 is a partially cut rear view of a vehicle and of the loudspeaker system of FIG. 1 installed in a lower part of a trunk of the vehicle under a spare tire;

(6) FIG. 5 is a partially cut rear view of a vehicle and of the loudspeaker system of FIG. 1 installed in a side part of the vehicle;

(7) FIG. 6 is a sectional view of a variant of the loudspeaker system of FIG. 1;

(8) FIG. 7 is a partially cut top view of the loudspeaker system of FIG. 6;

(9) FIG. 8 is a plan view of a variant of the loudspeaker system of FIG. 6;

(10) FIG. 9 is a front view of the box of the loudspeaker system of FIG. 8;

(11) FIG. 10 is a side view of the box of the loudspeaker system of FIG. 8;

(12) FIG. 11 is an axial view of a variant of the loudspeaker system according to the invention.

(13) With reference to the Figures, the loudspeaker system of the invention is described, which is generally indicated with reference numeral 100.

(14) With reference to FIG. 1, the system (100) comprises a wall (1) of a frame of a vehicle that separates an exterior from an interior of the vehicle. The interior of the vehicle can be the driver and passenger compartment or a compartment of the vehicle in communication with the driver and passenger compartment of the vehicle or adjacent to it. The wall (1) of the frame of the vehicle has a through hole (10).

(15) A box (2) is mounted in the wall (1) in correspondence of the through hole (10) of the wall. The box (2) is facing inwards. A loudspeaker (L) is mounted in the box (2). The box (2) coupled with the wall (1) of the vehicle forms a loudspeaker system of infinite baffle type.

(16) The box (2) comprises a bottom wall (20), an upper wall (21) and lateral walls (22) that connect the bottom wall (20) to the upper wall (21).

(17) The upper wall (21) is provided with an opening (23) intended to receive the loudspeaker (L).

(18) The loudspeaker (L) comprises a basket (3) provided with a lower wall (30) that radially protrudes towards the interior of the basket, an upper wall (31) that radially protrudes towards the exterior of the basket and a lateral wall (32) that connects the lower wall to the upper wall. The basket (3) substantially has a truncated-conical shape with increasing diameter going from the lower wall to the upper wall. The lateral wall (32) of the basket is provided with openings to let air pass through. The basket (3) is an open basket of standard type that is commonly used in loudspeakers.

(19) The upper wall (31) of the basket is fixed to the upper wall (21) of the box, in such a way that the basket passes through the opening (23) of the box and is contained in the box.

(20) A magnetic unit (4) is fixed to the basket (3). The magnetic unit (4) comprises: a lower polar plate (40) (T-Yoke), with T-shaped cross-section, comprising a cylindrical core (41) that protrudes axially from the plate, a permanent magnet (42) with toroidal shape, disposed on the lower polar plate, around a cylindrical core (41), and an upper polar plate (43), with toroidal shape, disposed on the permanent magnet (42).

(21) In view of the above, an air gap (T) is formed between the upper polar plate (43) and the core (41).

(22) A coil (5) is supported by a cylinder (50).

(23) A centering device (6), which is composed of elastic corrugations, is fixed to the basket (3) and to the cylinder (50) of the coil, in such a way to center and support the coil (5) in the air gap (T).

(24) A truncated-conical membrane (7) is centrally fixed to the cylinder (50) of the coil.

(25) An edge (60), in the form of an elastic suspension, is peripherally fixed to the membrane (7) and to the upper wall (31) of the basket, in such a way that the membrane (7) has a truncated-conical shape with increasing diameter going from the cylinder of the coil towards the upper wall of the basket.

(26) A covering element (61), which is known as dustcap, is centrally disposed on the membrane (7) in such a way to cover the cylinder of the coil.

(27) The loudspeaker (L) has an axis (Y) that coincides with the axis of the cylinder (50).

(28) When the static magnetic field in the air gap (T), which is generated by the magnetic unit (4), interacts with the electrical current that flows in the coil (5), a force is generated on the coil. Such a force axially moves the cylinder (50) of the coil and makes the membrane (7) vibrate, with consequent sound emission.

(29) In the embodiment of FIG. 1, the bottom wall (20) of the box is fixed to the wall (1) of the frame of the vehicle. The lower wall (20) has a hole (27) with a substantially circular shape.

(30) A back resonance chamber (C1) is formed in the box (2), being defined by the walls of the box, by the membrane (7) and by the edge (60). Such a back resonance chamber (C1) is in communication with the exterior by means of the hole (27) obtained in the lower wall of the box. Therefore the back resonance chamber (C1) and the hole (27) act as Helmholtz's resonator.

(31) Both the basket (5) and the magnetic unit (4) are disposed inside the box (2) and contained inside the back resonance chamber (C1). The basket (3) must be open to let air pass through.

(32) Nevertheless, it must be considered that the volume of the back resonance chamber (C1) is larger than a front volume (C2) formed by the truncated-conical volume of the membrane (7).

(33) In order to obtain a frequency band with a higher low frequency width compared to the frequency band of the loudspeaker mounted in a closed box with typical volume, the hole (27) of the flange of the box is provided with a partition (8) with variable thickness made of sound-absorbing material, such as for example agglomerates of natural fibers, synthetic fibers or open-cell foam.

(34) The main function of the partition (8) is to modify the frequency response and the transient response of the loudspeaker system by acoustic power dissipation in function of frequency. Said frequency responses are controlled by changing the geometry and the material of the partition (8).

(35) The additional and necessary function of the partition (8) is to protect the loudspeaker against weather agents and the intrusion of foreign matter (dust, sand, stones, etc.). The partition (8) has a thickness comprised between 0.1 and 40 mm.

(36) In FIG. 1 the hole (27) has an axis that coincides with the axis (Y) of the loudspeaker. Nevertheless, the hole (27) may have an axis that does not coincide with the axis (Y) of the loudspeaker.

(37) FIGS. 2 and 3 show an embodiment wherein the system (100) is mounted in an upper part of a trunk (B) of a vehicle. In such a case, the wall (1) of the vehicle where the box (2) is mounted is a wall disposed in the upper part of the trunk (B) of the vehicle. The box (2) is mounted on a substantially horizontal wall (1) and consequently the axis of the loudspeaker is substantially vertical.

(38) FIG. 4 shows an embodiment wherein the system (100) is mounted in a lower part of a trunk (B) of a vehicle, where a spare tire (S) is generally positioned. In such a case the wall (1) of the vehicle where the box (2) is mounted is a bottom wall of the trunk (B) of the vehicle and the box (2) is disposed between the bottom wall (11) of the trunk and the hub (H) of the spare tire.

(39) FIG. 5 shows an embodiment wherein the system (100) is mounted in a wall (1) of the vehicle, near a fender (P) of the vehicle. In such a case, the box (2) is mounted on a substantially vertical wall (1) and consequently the axis of the loudspeaker is substantially horizontal.

(40) In the following description the parts that are identical or corresponding to the parts described above are identified with the same numerals, omitting their detailed description.

(41) FIGS. 6 and 7 show a variant of the system (100), wherein the hole (27) that receives the partition (8) of sound-absorbing material is disposed in a lateral wall (22) of the box.

(42) In such a case, the hole (27) of the box has an axis (X) orthogonal to the axis (Y) of the loudspeaker (L) and substantially passing through the end of the core (41) of the magnetic unit.

(43) FIGS. 8 and 10 show a variant of the system (100), wherein the hole (27) that receives the partition (8) of sound-absorbing material is disposed in a duct (25) that protrudes laterally from a lateral wall (22) of the box. The hole (27) has a rectangular shape. The duct (25) ends with a flange (26) that is fixed to the wall (1) of the frame of the vehicle. A grill (29) is disposed on the front wall of the box, in such a way to cover the loudspeaker (L) disposed in the box.

(44) Although not shown in the figures, the front wall (21) of the box may be sufficiently large with respect to the loudspeaker (L). In such a case the hole (27) that receives the partition (8) may be obtained in the front wall (21) of the box.

(45) FIG. 11 shows a variant of the system (100), wherein the back wall (20) of the box is not directly fixed to the wall (1) of the frame. In fact, a connection pipe or duct (25) protrudes in the back from the back wall (20) of the box, around the hole (27) that receives the partition (8) for fixing to the wall (1) of the frame. In such a case, the duct (25) has a flange (26) for fixing to the wall of the frame.

(46) A number of changes may be made to the present embodiments of the invention, all within the reach of an expert in the field, without departing from the scope of the invention.