Loudspeakers and methods of loudspeaking

Abstract

The loudspeaker (1) comprises an active radiator (30) movable along a longitudinal axis (X), a ferromagnetic circuit comprising a central core (21) extending along the longitudinal axis (X) from a first end (21A) near the active radiator (30) to a second end (21B), and a portion of the central core (21) located outside the central core (21) and extending from the first end (21A) of the central core (21) to define a gap (T) through which a coil (30) connected to the active radiator (30) can move longitudinally. The ferromagnetic circuit includes a separated outer core (22) and a longitudinally oriented polarized main magnet (23) having a ring shape and circulating through the ferromagnetic circuit to generate a main magnetic flux that traverses the gap (T) transversely, and a secondary magnet (50) located at the first end (21A) of the central core (21) to generate a secondary magnetic flux that is longitudinally oriented and traverses the gap (T) transversely (V) and closes itself outside the ferromagnetic circuit.

Description

[Technical Field]

[0001] The present invention relates to a loudspeaker and a method for loudspeaking. [Background technology]

[0002] Generally, a loudspeaker comprises a ferromagnetic circuit through which a magnetic field is generated by a coil or permanent magnet through which an electric current flows. The loudspeaker comprises a coil or magnet that is movable within a gap in the ferromagnetic circuit under the action of the magnetic field, and the coil or magnet is an (active) radiator whose movement directly or indirectly drives an (active) radiator that generates sound. Thus, the ferromagnetic circuit is subdivided by the gap into a central core (inside the gap) and an outer core (outside the gap).

[0003] In this regard, prior art has shown that magnetic flux circulating in a ferromagnetic circuit can be generated by magnets placed in the outer core. This type of solution is known, for example, from patent documents US2015 / 0030199A and US8135162B2.

[0004] Reference US2015 / 0030199A proposes generating a magnetic field shielding effect by an additional magnet (labeled 105 in the drawing) that extends beneath both the central and outer cores and is positioned beneath the ferromagnetic circuit.

[0005] The US8135162B2 loudspeaker proposes increasing the magnetic flux circulating in the ferromagnetic circuit by using a main magnet and additional magnets aligned with it (the two magnets are labeled 104 and 108 in the drawing).

[0006] Patent documents US5461677A, US7068807B2, JPH10112896A, and US2016 / 227325A1 describe other examples of loudspeakers with additional magnets. In document US2016 / 227325A1, the additional magnets located at the ends of the central core near the radiator are known as backing magnets, i.e., magnets used to reduce magnetic flux loss. For this purpose, the additional magnets have polarity opposite to that of the magnets located in the outer core.

[0007] Patent document US7068807B2 also describes an additional magnet whose polarity is opposite to that of the magnets in the outer core. Patent document JPH10112896A describes an additional magnet positioned at the end of the central core near the proximal end of the radiator, inside a recess formed in the central core. This configuration has the disadvantage that the magnetic flux increases at the central pole, particularly in the portion of the central pole near the gap and the additional magnet, and thereby saturates.

[0008] Patent document US5461677A relates to a loudspeaker that includes a ferrofluid material for cooling, in which case an additional magnet is used to hold the ferrofluid material into which the coil is immersed. To ensure heat exchange between the coil and the ferrofluid material, the movement of the coil within the gap must be restricted and not exceed the additional magnet. However, restricting the movement of the coil negatively affects the SPL parameter (i.e., the volume produced) of the loudspeaker. This problem can be avoided by using a larger additional magnet, but this unfortunately means an increase in the size and cost of the loudspeaker.

[0009] Therefore, there is a market demand for loudspeakers that are particularly compact (i.e., small) but at the same time offer very high performance. [Overview of the project]

[0010] The purpose of this disclosure is to provide a loudspeaker and a method for amplifying sound to overcome the shortcomings of the prior art described above.

[0011] In particular, the purpose of this disclosure is to provide a compact and high-performance loudspeaker.

[0012] Another objective is to provide a loudspeaker that features a particularly wide and linear frequency response.

[0013] These objectives are fully achieved by the loudspeaker and loudspeaker method of this disclosure as described in the claims.

[0014] In particular, the loudspeaker includes an active radiator that is movable along its longitudinal axis to generate sound waves.

[0015] The loudspeaker is equipped with a ferromagnetic circuit. The ferromagnetic circuit includes a central core extending along its longitudinal axis. The central core extends from a first end to a second end. The first end is proximal to the active radiator, and the second end is distal to the active radiator.

[0016] The ferromagnetic circuit includes an outer core located outside the central core. The outer core surrounds the longitudinal axis. Preferably, at least a portion of the outer core is separated from the central core. For example, the outer core is separated from a first end of the central core so as to define a longitudinally extending gap. In other words, the outer core is separated from the central core longitudinally so as to define a gap at the first end of the central core.

[0017] The loudspeaker is equipped with a magnetic field generator. The magnetic field generator may be inserted into the outer core or into the inner core. The magnetic field generator is configured to generate a principal magnetic flux that circulates through a ferromagnetic circuit, particularly traversing the gap in a transverse direction.

[0018] The magnetic field generator may be, for example, a coil or a permanent magnet that is coaxial with the longitudinal axis, i.e., wound around the longitudinal axis. Preferably, the loudspeaker includes a permanent magnet, i.e., a main magnet.

[0019] The main magnet is in a ring shape. The main magnet is inserted into the outer core. The main magnet is configured to generate a main magnetic flux. The main magnetic flux circulates through the ferromagnetic circuit so as to cross the gap in the transverse direction. Preferably, the main magnet constitutes the interruption of the outer core. The main magnet has a longitudinally directed polarization. The main magnetic flux crosses the central core along the transverse direction.

[0020] The loudspeaker comprises a movable element configured to move along a direction of movement parallel to the longitudinal axis in order to move the active radiator. The movable element can be a coil or a magnet. The movable element is located inside the gap and is preferably coaxial with the longitudinal axis.

[0021] Preferably, the loudspeaker comprises a coil coaxial with the longitudinal axis that is movable along a direction of movement parallel to the longitudinal axis in order to move the active radiator inside the gap.

[0022] The loudspeaker comprises an auxiliary magnet. The auxiliary magnet is aligned with the longitudinal axis. The auxiliary magnet is located at the first end of the central core so as to generate an auxiliary magnetic flux. The auxiliary magnetic flux crosses the gap in the transverse direction and closes itself outside the ferromagnetic circuit. Preferably, the auxiliary magnet has a longitudinally directed polarization. The auxiliary magnetic flux crosses the central core along a transverse direction that does not coincide with the transverse direction of the main magnetic flux. Thus, the magnetic flux density of the central core is reduced.

[0023] Preferably, the main magnet and the auxiliary magnet are longitudinally offset.

[0024] S Therefore, the presence of the auxiliary magnet has the effect of reducing the magnetic flux density of the central core and increasing the magnetic flux density crossing the gap. With the magnetic flux crossing the gap under the same conditions, this makes it possible to reduce the saturation level of the central core using a smaller and thus less expensive main magnet, which means that the central core can be made of a material that is not very inactive, and thus the central core can be less expensive and smaller.

[0025] In fact, other approaches are possible, including an approach of increasing the size of the central core or an approach of using an inert material characterized by a high saturation degree to prevent the saturation of the central core. However, such solutions make the loudspeaker difficult to handle and expensive. In the present invention, under the same conditions, the magnetic flux in the central core is significantly reduced as the magnetic flux to the gap, and thus, the dimensions of the loudspeaker can be reduced without using an expensive inert material.

[0026] Another effect of the auxiliary magnet is to reduce the magnetic flux loss (to the gap) and to result in a more uniform distribution in the gap. As a result, the force generated to move the coil located in the gap also becomes more symmetrical. Note that the use of the auxiliary magnet increases the loss outside the loudspeaker. Therefore, an additional auxiliary magnet according to the backing magnet configuration may be used.

[0027] In one example, the auxiliary magnet is arranged flush with the central core. In other words, the auxiliary magnet is circular, and its radius with respect to the longitudinal axis is equal to the (substantially) radius of the central core measured at the second end of the central core. The use of an auxiliary magnet whose radius is larger or smaller than the radius of the central core is also conceivable.

[0028] In one example, the auxiliary magnet has a lower surface that (directly or indirectly) contacts the first end of the central core and an upper surface on the opposite side of the lower surface. The upper surface and the lower surface extend to their respective development surfaces perpendicular to the longitudinal axis.

[0029] The auxiliary magnet has an outer surface that extends around the longitudinal axis (i.e., surrounds the longitudinal axis). In particular, the outer surface faces away from the longitudinal axis. The periphery included between the upper surface and the outer surface may have a chamfered surface (so as to define a chamfered edge). In other words, considering the cross-section of the auxiliary magnet passing through the auxiliary magnet along a plane including the longitudinal axis, the auxiliary magnet may have a trapezoidal cross-section. The chamfered edge is advantageous for facilitating the passage of the power cable.

[0030] Preferably, the first end of the central core extends (only) within a deployment plane perpendicular to the longitudinal axis. Thus, the lower surface of the auxiliary magnet is in contact (directly or indirectly) with the first end of the central core, defining a contact surface located within the deployment plane of the central core. The fact that the contact surface is located within the deployment plane of the central core (and therefore the auxiliary magnet is not located in a recess of the central core) reduces the risk of saturating the portion of the central core proximal to the auxiliary magnet and the gap.

[0031] In one example, the secondary magnet has an inner surface opposite to its outer surface, and the inner surface extends around the longitudinal axis and faces the longitudinal axis. Therefore, the secondary magnet can be annular, or ring-shaped.

[0032] In particular, the outer core may include an upper and a lower section. The upper and lower sections may be aligned longitudinally with respect to each other. The main magnet may be located between the upper and lower sections of the outer core, along a direction parallel to the longitudinal axis. The gap is defined by a portion of the outer surface of the central core, a portion of the upper surface facing the portion of the outer surface of the central core, and a portion of the surface of the main magnet.

[0033] With respect to a half-plane cross-section originating from the longitudinal axis, the outer core may have a larger radial range than the radial range of the central core. In other words, the outer core may extend to have a larger radial range than the radial range of the central core, where the radial direction is defined perpendicular to the longitudinal axis.

[0034] The upper part is ring-shaped. The upper part of the outer core has an inner surface that extends around the longitudinal axis and faces the longitudinal axis (in other words, is proximal to the longitudinal axis). The upper part also has an outer surface that extends around the longitudinal axis and is opposite to the inner surface.

[0035] For example, the area S of the inner surface at the top of the outer core. tp and the surface area S extending radially from the central core pp The ratio (measured with respect to a half-plane cross-section originating from the longitudinal axis) is 1.3 or less, particularly 1.6, and more specifically 2.

[0036] ratio S tp / S pp This represents the upper surface of the outer core through which a certain magnetic flux passes, relative to the cross-section of the central core through which a certain magnetic flux passes. With an outer core of the same size, the presence of auxiliary magnets makes it possible to reduce the cross-section of the central core (and thus reduce the size of the central core) in order to obtain high performance within limited dimensions and inertia.

[0037] The coil is configured to move along a direction of movement, preferably parallel to the longitudinal axis. The coil moves along the direction of movement between a first end and a second end opposite to the first end. The coil moves along the direction of movement such that the first end (or second end) moves between the maximum and minimum points. At the maximum point, the radiator moves away from the central core, and at the minimum point, the radiator moves towards the central core. In particular, at the maximum point, the coil moves (completely or partially) out of the gap (in particular, at least one of the ends of the coil moves out of the gap, more specifically the first end of the coil moves out of the gap). In particular, at the maximum point, the first end can move longitudinally beyond the auxiliary magnet. As it moves between the maximum and minimum points, the first end (or second end) of the coil passes through an equilibrium point, preferably equidistant from the maximum and minimum points.

[0038] Preferably, the coil moves through the air gap.

[0039] In one example, the height H of the inner surface at the top of the outer core. pp The distance X of the first end of the coil between the equilibrium point and the maximum point. max The ratio is less than or equal to 2, particularly 1.6, and more specifically 1.4 (in particular, the height of the outer surface and the distance between the equilibrium point and the maximum point are measured parallel to the longitudinal axis). This ratio represents the distance the coil travels relative to the height of the top of the outer core. The greater the distance the coil travels, the more the frequency characteristics of the loudspeaker are extended.

[0040] In one example, the height H of the inner surface at the top of the outer core.pp and the height H of the coil vc The ratio with respect to is measured parallel to the longitudinal axis and is greater than or less than 1 (i.e., different from 1). Preferably, this ratio is 1.5 or less, particularly less than 1.8, and more specifically less than 2. In fact, for the linearity of the response of a good loudspeaker, it is useful for the height of the coil to be considerably lower (or higher but not approximately equal) than the height of the upper part of the outer core.

[0041] In one example, the height H of the inner surface of the upper part of the outer core pp and the height H of the main magnet m The ratio with respect to is measured parallel to the longitudinal axis and is 1.55 or less, particularly 1.7 or less, and more specifically 2 or less. In fact, in order to obtain high performance while keeping the size small, it is useful for the height of the main magnet to be restricted compared to the height of the upper part.

[0042] In one example, the diameter D of the suspension d and the diameter D of the main magnet<00000​​​​​​​​​​​​​​

[0046] In one example, a gap defines a void. The loudspeaker has a centering element surrounding its longitudinal axis. The centering element is positioned between the radiator and the top of the outer core. The centering element and the top surface of the core define a void. The void defined by the gap and the void defined by the centering element and the top surface are in communication in the air.

[0047] In one embodiment, the outer core is also separated from the second end of the central core to define an additional gap extending longitudinally. Preferably, the additional gap is aligned with the gap. In this case, the principal magnetic flux traverses the additional gap in an additional transverse direction. Preferably, the additional transverse direction is opposite to the first transverse direction.

[0048] The loudspeaker may include an additional auxiliary magnet aligned with the longitudinal axis and located at the second end of the central core. The additional auxiliary magnet generates an additional auxiliary magnetic flux that traverses an additional gap in an additional transverse direction and closes itself outside the ferromagnetic circuit. Preferably, the additional auxiliary magnet has a longitudinally oriented polarization. The additional auxiliary magnets and the main magnet may be aligned longitudinally with each other. The main magnet may be offset from the additional auxiliary magnets and the main magnet. The additional auxiliary magnetic flux is configured to traverse the central core in the opposite direction to the direction of the main magnetic flux.

[0049] Additional auxiliary magnets may be made with the same properties as those described for the auxiliary magnets.

[0050] The loudspeaker may include an additional coil located in an additional gap. The additional coil is coaxial with the longitudinal axis and movable along an additional direction of movement parallel to the longitudinal axis. Preferably, the additional direction of movement of the additional coil coincides with the direction of movement of the coil. That is, the coil and the additional coil are aligned along the same direction parallel to the longitudinal axis. The coil and the additional coil may be configured to move along the same direction and the additional direction of movement, respectively, along the same direction or in opposite directions.

[0051] In particular, the additional gap may be defined by a portion of the outer surface of the central core, a portion of the lower surface facing the portion of the outer surface of the central core, and a portion of the surface of the main magnet.

[0052] The loudspeaker may include a cylindrical support surrounding a central core and positioned in a gap, and the coil may be wound around the cylindrical support, that is, the coil may be integrated with the cylindrical support so as to move together with the cylindrical support. The cylindrical support is connected to a radiator so as to move the radiator in response to the movement of the coil along the direction of movement.

[0053] In one embodiment, the cylindrical support is located in an additional gap, or in a gap and an additional gap, and the additional coil may be wound around the cylindrical support, i.e., the additional coil may be integrated with the cylindrical support so as to move together with the cylindrical support. In this case, the coil and the additional coil move in the same direction along the same direction of movement.

[0054] In further embodiments, the loudspeaker may include an additional active radiator that is movable along a longitudinal axis to generate sound waves and faces the active radiator, and the loudspeaker may include an additional cylindrical support surrounding a central core in an additional gap, and an additional coil may be wound around the cylindrical support, i.e., the additional coil may be integrated with the additional cylindrical support so as to move together with the additional cylindrical support. In this case, the coil and the additional coil move in the same direction and / or opposite directions along the same direction of movement.

[0055] In one example, the central core comprises a cylindrical hole. The cylindrical hole may extend between a first end and a second end of the central core. In particular, the cylindrical hole may extend along the longitudinal axis between the inlet of the second end and the outlet of the first end of the central core. The central core may have cylindrical symmetry about the longitudinal axis.

[0056] In one example, the loudspeaker includes a power cable for connecting a power supply unit (i.e., an amplifier that functions as a power supply unit) to the coil. In particular, a cylindrical hole may define a passage for guiding the power cable from the entrance to the exit of the cylindrical hole.

[0057] In one example, the loudspeaker may include a light diffuser, i.e., a dome configured to diffuse light. Preferably, the diffuser is located at the exit of a cylindrical hole. The light diffuser may protrude toward an active radiator, i.e., it may be configured to diffuse light toward the active radiator.

[0058] The loudspeaker may be equipped with a dust dome. In one embodiment, the light diffuser may be a dust dome, i.e., the dust dome is configured to diffuse light. In a further embodiment, the light diffuser may be configured to diffuse light toward the dust dome, and the dust dome is at least partially transparent to light. Thus, the light diffuser and the dust dome may be exactly the same, or they may be separate components of the loudspeaker. The active radiator may be at least partially transparent to light.

[0059] The loudspeaker may include a light source configured to emit light, i.e., to generate light, and preferably located at the entrance of a cylindrical hole. The loudspeaker may also include a light guide configured to connect the light source to a light diffuser, thereby diffusing the light generated by the light source toward an active radiator. The light source, light diffuser, and light guide may constitute a lighting system.

[0060] The loudspeaker may be an electronic card, preferably an electronic card equipped with a control unit for driving the loudspeaker, i.e., the coil. The light source may be connected to the electronic card. The control unit may be programmed to drive the light source.

[0061] Therefore, the holes are filled with power cables and optical guides.

[0062] It should be noted that the lighting system described above may be applicable to any type of loudspeaker that has a cylindrical hole.

[0063] Accordingly, the Disclosure also provides an active radiator movable along a longitudinal axis to generate sound waves, and a loudspeaker comprising a ferromagnetic circuit. The ferromagnetic circuit may include a central core extending along the longitudinal axis from a first end proximal to the active radiator to a second end distal to the active radiator, and an outer core located outside the central core, which surrounds the longitudinal axis and is separated from the first end of the central core to define a longitudinally extending gap. The loudspeaker (i.e., the ferromagnetic circuit) comprises a magnetic field generator, for example, a main coil or main magnet, configured to generate a main magnetic flux circulating through the ferromagnetic circuit so as to traverse the gap transversely. The magnetic field generator may be located in the central core or the outer core. The loudspeaker comprises a movable element, for example, a movable magnet or coil, located in the gap, coaxial with the longitudinal axis, and movable along a direction of movement parallel to the longitudinal axis to move the active radiator (directly or indirectly). In this case, the central core has a cylindrical hole extending along the longitudinal axis between the inlet at the second end of the central core and the outlet at the first end. The central core may have cylindrical symmetry about the longitudinal axis. The loudspeaker includes a lighting system. The lighting system may include a diffuser configured to diffuse light. The diffuser may have a dome shape. Preferably, the diffuser is located at the outlet of the cylindrical hole. The diffuser may protrude toward the active radiator, i.e., it may be configured to diffuse light toward the active radiator.

[0064] The loudspeaker may be equipped with a dust dome (configured to prevent dust from entering the inside of the loudspeaker). A light diffuser may protrude toward the dust dome to diffuse light toward the dome. In particular, the dust dome is at least partially transparent to light.

[0065] The loudspeaker (i.e., lighting system) may include a light source (e.g., one or more LEDs) configured to emit light, i.e., generate light. Preferably, the light source is located at the entrance of a cylindrical hole.

[0066] The loudspeaker (i.e., lighting system) may include a light guide configured to connect the light source to a light diffuser. In this way, the light produced by the light source is diffused toward the active radiator.

[0067] The loudspeaker may also include an electronic card, preferably equipped with a control unit for driving a diffuser, i.e., a coil. The light source may be connected to the electronic card or mounted on the electronic card. The control unit may be programmed to drive (i.e., control) the light source.

[0068] The control unit may control the light source in accordance with the operating status of the loudspeaker. For example, the control unit may drive the light source to switch on and / or off in response to a loudspeaker malfunction. In this way, the lighting system can constitute a diagnostic indicator of the loudspeaker's operation. For example, the control unit may be programmed to drive the light source in response to an electrical signal used to supply power to a coil. That is, the control unit may be programmed to drive the light source based on the sound produced by the loudspeaker.

[0069] In one example, a loudspeaker may be part of a group of loudspeakers equipped with a lighting system. For instance, the lighting system may be used to provide visible evidence indicating which of the group of loudspeakers is emitting sound.

[0070] Preferably, the polarizations of the main magnet and the secondary magnet coincide with the longitudinal direction. If there are additional secondary magnets, the polarization of the additional secondary magnets also coincides with the polarization of the main magnet (and therefore also the secondary magnets) along the longitudinal direction. In other words, the main magnet and the secondary magnets (and any additional secondary magnets) each have a north pole and a south pole that are oriented longitudinally in the same direction.

[0071] Preferably, the coil has a longitudinal range smaller than the longitudinal range of the gap, i.e., the coil is completely located inside the gap. In other words, the ratio of the longitudinal range of the gap to the longitudinal range of the coil is greater than 1, i.e., the gap and the coil constitute an underhang configuration system. In this configuration, the greater the ratio between the ranges is greater than 1, the more apparent the advantages obtained from the present invention become.

[0072] If present, the additional coil has a longitudinal range smaller than the range of the additional gap, meaning the additional coil can be entirely located inside the additional gap.

[0073] This disclosure also provides a method for amplifying sound.

[0074] The method includes the step of providing an active radiator that is movable along its longitudinal axis for generating sound waves.

[0075] The method includes the step of providing a ferromagnetic circuit. The ferromagnetic circuit may be made according to one or more features described herein. Preferably, the ferromagnetic circuit includes a central core extending along the longitudinal axis from a first end proximal to the active radiator to a second end distal to the active radiator.

[0076] Preferably, the ferromagnetic circuit includes an outer core, which is located outside the central core, surrounds the longitudinal axis, and is separated from the first end of the central core to define a longitudinally extending gap. Preferably, the ferromagnetic circuit includes a ring-shaped main magnet inserted into the outer core.

[0077] Preferably, the main magnet constitutes a break in the outer core. The main magnet has polarization oriented in the longitudinal direction.

[0078] A coil can be used instead of a main magnet.

[0079] The method includes the step of providing a movable element located inside the gap and coaxial with the longitudinal axis. The movable element may be a magnet, more preferably a coil.

[0080] This method includes the step of generating a main magnetic flux that circulates through a ferromagnetic circuit so as to traverse the gap in the transverse direction via a main magnet.

[0081] This method includes the step of moving a coil (or magnet) along a direction of movement parallel to the longitudinal axis in order to move an active radiator in response to the generated magnetic flux.

[0082] The method includes the step of generating a secondary magnetic flux that traverses the gap in the transverse direction and closes itself outside the ferromagnetic circuit, such that the total magnetic flux density traversing the gap is greater than the main magnetic flux density.

[0083] In particular, the secondary magnetic flux is self-contained outside the ferromagnetic circuit, traversing the central core in the opposite direction to the main magnetic flux, and the total magnetic flux density traversing the gap is greater than the main magnetic flux density. At the same time, the magnetic flux density traversing the central core is lower than the main magnetic flux density.

[0084] The secondary magnetic flux may be generated by a secondary magnet that is aligned with the longitudinal axis and located at the first end of the central core. In other words, the method may include the step of providing a secondary magnet that is aligned with the longitudinal axis and located at the first end of the central core. Preferably, the secondary magnet has a polarization oriented in the longitudinal direction.

[0085] Preferably, the main magnet and the secondary magnet are offset in the longitudinal direction.

[0086] The auxiliary magnet may be in direct contact with the first end of the central core, or through a region of high permeability.

[0087] This method may include the step of simultaneously magnetizing a main magnet inserted in the outer core and a secondary magnet located at the first end of the central core.

[0088] In one example, the outer core is separated from the central core so as to define an additional gap that extends longitudinally and is aligned with the gap, and the main magnetic flux traverses the additional gap in an additional transverse direction.

[0089] The method may include the step of providing an additional coil located in an additional gap and coaxial with the longitudinal axis. The method may also include the step of moving the additional coil along a direction of movement parallel to the longitudinal axis, depending on the magnetic flux generated.

[0090] The method may include the step of generating an additional secondary magnetic flux that traverses an additional gap in an additional transverse direction and closes itself outside the ferromagnetic circuit, such that the total magnetic flux density traversing the additional gap is greater than the main magnetic flux density. In particular, the additional secondary magnetic flux closes itself outside the ferromagnetic circuit, traverses the central core in the opposite direction to the main magnetic flux, and the total magnetic flux density traversing the additional gap is greater than the main magnetic flux density. The magnetic flux density traversing the central core is less than the main magnetic flux density.

[0091] For example, the method may include the step of providing an additional auxiliary magnet that is aligned with the longitudinal axis and located at the second end of the central core. In other words, the additional auxiliary magnetic flux is generated by the additional auxiliary magnet. Preferably, the additional auxiliary magnet has a polarization oriented in the longitudinal direction.

[0092] The additional auxiliary magnets may be aligned longitudinally. The main magnet may be offset longitudinally from the additional auxiliary magnets.

[0093] In one example of this method, the coil has a longitudinal range smaller than the longitudinal range of the gap. [Brief explanation of the drawing]

[0094] This and other features will become apparent from the following description of preferred embodiments shown in the accompanying drawings as non-limiting examples. [Figure 1A] A cross-section of a loudspeaker 1 according to one or more embodiments of this disclosure is shown. [Figure 1B] This shows a cross-section of a conventional loudspeaker 1. [Figure 2A] A cross-section of a loudspeaker 1 according to one or more embodiments of this disclosure is shown. [Figure 2B] This shows a cross-section of a conventional loudspeaker 1. [Figure 3] The present disclosure shows one or more embodiments of a loudspeaker 1. [Figure 4] An exploded view of the loudspeaker 1 according to one or more embodiments of this disclosure is shown. [Figure 5A-5B] A schematic representation of one or more embodiments of the present disclosure of loudspeaker 1 is shown. [Figure 6A-6B] A cross-section of a loudspeaker 1 according to one or more embodiments of the present disclosure, equipped with a lighting system, is shown. [Figure 6C-6E] The image shows a cross-section of a loudspeaker 1 according to one or more embodiments of the present disclosure, having radiators at different positions with respect to the longitudinal axis. [Figure 7A] This document shows a simulation of the magnetic flux circulating through loudspeaker 1 according to one or more aspects of the present disclosure. [Figure 7B] This shows a simulation of the circulating magnetic flux in a conventional loudspeaker. [Figures 8A-8B] The direction of the magnetic flux in a loudspeaker 1 according to one or more embodiments of this disclosure is schematically shown. [Figure 9] A cross-section of a loudspeaker 1 according to one or more embodiments of this disclosure is shown. [Modes for carrying out the invention]

[0095] The number 1 in the attached drawing indicates a loudspeaker.

[0096] The loudspeaker 1 includes an active radiator 30 that is movable along the longitudinal axis X to generate sound waves.

[0097] The loudspeaker 1 includes a ferromagnetic circuit. The ferromagnetic circuit includes a central core 21 that extends along the longitudinal axis X from a first end 21A near the active radiator 30 to a second end 21B near the active radiator 30. For example, the central core 21 may be made of iron.

[0098] The ferromagnetic circuit includes an outer core 22 located outside the central core 21 and surrounding the longitudinal axis X. For example, the outer core 22 may be made of iron. The outer core 22 includes an upper part 22A and a lower part 22B that are longitudinally aligned with each other. The upper part 22A is separated from the first end of the central core 21 so as to define a longitudinally extending gap T.

[0099] The ferromagnetic circuit includes a ring-shaped main magnet 23 inserted longitudinally into the outer core 22 between the upper part 22A and the lower part 22B.

[0100] In one embodiment, the lower portion 22B is in direct contact with the central core 21 at the second end portion 21B. For example, the lower portion 22B may be defined by the lower part of the second end portion 21B extending away from the longitudinal axis X. In this case, the gap T is defined longitudinally by the surfaces of the upper portion 22A of the outer core 22 and a portion of the inner surface of the central core 21, which face each other.

[0101] The main magnet 23 is also separated from the central core 21.

[0102] The main magnet 23 generates a main magnetic flux that circulates through the ferromagnetic circuit and traverses the gap T in the transverse direction V. The main magnet 23 has a north pole and a south pole oriented longitudinally relative to each other. The north pole may be in contact with the upper part 22A of the outer core 22, and the south pole may be in contact with the lower part 22B of the outer core 22, and vice versa; that is, the north pole may be in contact with the lower part 22B of the outer core 22, and the south pole may be in contact with the upper part 22A of the outer core 22.

[0103] The loudspeaker 1 is located in a gap T and includes a coil 40 that is coaxial with the longitudinal axis X and movable along a direction M of movement parallel to the longitudinal axis X.

[0104] Preferably, the coil 40 has a longitudinal range smaller than the longitudinal range of the gap T, meaning that the coil 40 is completely located inside the gap T. In particular, the coil 40 has a longitudinal range smaller than the longitudinal range of the upper part 22A of the outer core 22.

[0105] The loudspeaker 1 comprises a cylindrical support 60 surrounding a central core 21 and located in a gap T. The coil 40 is wound around the cylindrical support 60, and the cylindrical support 60 moves together with the coil 40 along the direction of movement M. The cylindrical support 60 is connected to an active radiator 30 to move the radiator 30 in response to the movement of the coil 40.

[0106] The loudspeaker 1 is equipped with a basket 70, and the radiator 30 is fixed to the basket 70 via a suspension 31. The loudspeaker 1 is equipped with a dust dome 32 fixed to the radiator 30.

[0107] The loudspeaker 1 is equipped with a guide system. In the illustrated example, the guide system is a centering element 33 connected to a cylindrical support 60 and configured to center and hold the cylindrical support 60, and consequently the coil 40, within the gap T during movement.

[0108] The centering element 33 may be connected to the fixed structure by the support ring 24.

[0109] In examples not shown, the guide system may be constructed in accordance with the one disclosed in Patent Document 102022000026061 in the name of the present applicant and incorporated herein by reference.

[0110] The loudspeaker 1 includes a secondary magnet 50 located at the first end 21A of the central core 21 and aligned with the longitudinal axis X. The secondary magnet 50 is in direct contact with the first end 21A of the central core 21.

[0111] The auxiliary magnet 50 is configured to generate an auxiliary magnetic flux that traverses the gap T in the transverse direction V and closes itself outside the ferromagnetic circuit.

[0112] The polarization of the main magnet 23 and the polarization of the auxiliary magnet 50 coincide with respect to the longitudinal direction; that is, the main magnet 23 and the auxiliary magnet 50 each have a north pole and a south pole oriented longitudinally in the same direction.

[0113] The main magnet 23, the auxiliary magnet 50, the central core 21, and the outer core 22 define the fixed structure of the loudspeaker 1, while the coil 40, the cylindrical support 60, and the radiator 30 define the movable operating unit.

[0114] In one embodiment, the lower portion 22B is separated from the second end portion 21B of the central core 21 to define an additional longitudinal gap T'. In this case, the additional gap T' is defined longitudinally by the surfaces of the lower portion 22B of the outer core 22 and a portion of the inner surface of the central core 21, which face each other.

[0115] Therefore, the magnetic flux generated by the main magnet 23 also traverses the additional gap in an additional transverse direction. The loudspeaker 1 may also include an additional coil 40' located in the additional gap T', coaxial with the longitudinal axis X, parallel to the longitudinal axis X, and movable along an additional direction of movement M' which preferably coincides with the direction of movement M of the coil 40. The additional coil 40' may have a longitudinal range smaller than the longitudinal range of the additional gap T', meaning that the additional coil 40' is entirely located inside the additional gap T'. In particular, the additional coil 40' may have a longitudinal range smaller than the longitudinal range of the lower part 22B of the outer core 22.

[0116] In the embodiment shown simply as an example in Figure 5A, the cylindrical support 60 extends longitudinally to an additional gap T', and the additional coil 40' is wound around the cylindrical support 60 so as to move together with the cylindrical support and the coil 40. In this case, the direction of movement and the orientation of movement coincide.

[0117] In another embodiment, simply illustrated in Figure 5B, the loudspeaker 1 includes an additional cylindrical support 60' that positions the central core 21 and is located in an additional gap T'. An additional coil 40' is wound around the additional cylindrical support 60', and therefore the additional cylindrical support 60' moves together with the additional coil 40' along an additional direction of movement M'. In this case, the additional cylindrical support 60' may be connected to an additional active radiator to move the additional active radiator in response to the movement of the additional coil 40'. In this case, preferably the directions of movement M and M' of the coil 40 and the additional coil 40' coincide, but the directions of movement may be the same or opposite. The additional radiator may be secured to the basket 70 by an additional suspension, and the loudspeaker 1 may include an additional dust dome secured to the additional radiator. The loudspeaker 1 may also include an additional centering element connected to an additional cylindrical support 60', configured to center and hold the additional cylindrical support 60', and consequently the additional coil 40', within an additional gap T' during movement. The loudspeaker 1 may also include an additional auxiliary magnet 50' located at the second end 21B of the central core 21 and aligned with the longitudinal axis X. The additional auxiliary magnet 50' is in direct contact with the second end 21B of the central core 21.

[0118] The additional sub-magnet 50' is configured to traverse an additional gap T' in an additional transverse direction V, generating an additional sub-magnetic flux that closes itself outside the ferromagnetic circuit.

[0119] The polarizations of the main magnet 23, the auxiliary magnet 50, and the additional auxiliary magnet 50' coincide with the longitudinal direction; that is, the main magnet 23, the auxiliary magnet 50, and the additional auxiliary magnet 50' each have a north pole and a south pole oriented longitudinally in the same direction.

[0120] The central core 21 may have a cylindrical hole F. The cylindrical hole F extends along the longitudinal axis X between the inlet of the second end 21B of the central core 21 and the outlet of the first end 21A.

[0121] The cylindrical hole F may define a passage for the power cable 80 of the coil 40 (and any additional coils 40', if present) to pass through the cylindrical hole F from the entrance to the exit.

[0122] Figures 6A and 6B show an example of a loudspeaker 1 equipped with a lighting system. The lighting system includes a light diffuser 81 that is dome-shaped and located at the exit of a cylindrical hole F in order to diffuse light toward a dust dome 32 that is partially transparent to light. The lighting system includes a light source 82 to generate light. The loudspeaker 1 may also include an electronic card 83 with a control unit programmed to drive the loudspeaker 1. The light source 82 may be located on the electronic card 83 or controlled by the control unit. The light source 82 is located at the entrance of the cylindrical hole F. The lighting system includes a light guide 84 configured to connect the light source 82 to the light diffuser 81.

[0123] The electronic card 83 may have a memory that is preferably accessible from the control unit of the electronic card 83. The memory may be accessible from an external control unit of the loudspeaker 1. The memory may contain information representing the loudspeaker 1. The information may be contained in the memory in an encrypted form. The information may include a serial number (identifying the loudspeaker 1) and / or a lot number (identifying a group of loudspeakers including the loudspeaker 1) and / or information about the production facility where the loudspeaker 1 was manufactured and / or other information.

[0124] The information may include several electromechanical parameters related to the loudspeaker 1. For example, the electromechanical parameters may describe typical features and specifications of the loudspeaker 1 (in numerical, tabular, or matrix format), and the information may include, for example, the movable mass value and / or the resonant frequency value and / or the change in the force coefficient as a function of the coil position and / or the inductance as a function of frequency and coil position and / or other features.

[0125] The information contained in the memory may be accessible from an external control unit, for example, to control the functions of the loudspeaker 1.

[0126] In one example, the electronic card 83 comprises a plurality of conductive tracks 85. The conductive tracks 85 may be configured to carry electrical signals, i.e., signals to be converted into audio signals, and / or power. The conductive tracks 85 may also be configured to carry power to, for example, a light source and / or memory.

[0127] The electronic card 83 includes a connector 86 for receiving power from the power supply unit, that is, from an amplifier that functions as a power supply unit.

[0128] Figures 6C, 6D, and 6E show the operation sequence of the loudspeaker 1. As the coil 40 moves along the direction of movement (i.e., along the longitudinal axis X), the radiator 30, which is (indirectly) connected to the coil 40, also moves along the longitudinal axis X.

[0129] Figures 7A and 7B show the magnetic flux patterns in the loudspeaker 1 of the present invention and the loudspeaker 1 of the prior art, respectively. [Prior art documents] [Patent Documents]

[0130] [Patent Document 1] US2015 / 0030199A [Patent Document 2] US8135162B2 [Patent Document 3] US5461677A [Patent Document 4] US7068807B2 [Patent Document 5] JPH10112896A [Patent Document 6] US2016 / 227325A1 [Patent Document 7] 102022000026061

Claims

1. A loudspeaker (1), - An active radiator (30) that is movable along the longitudinal axis (X) to generate sound waves, - A ferromagnetic circuit, A central core (21) extends along the longitudinal axis (X) from a first end (21A) near the proximal end of the active radiator (30) to a second end (21B) near the distal end of the active radiator (30), An outer core (22) located outside the central core (21), surrounding the longitudinal axis (X), and separated from the first end (21A) of the central core (21) so as to define a longitudinally extending gap (T), A ferromagnetic circuit includes a main magnet (23) having a ring shape and longitudinally oriented polarization, which is inserted into the outer core (22) so as to circulate through the ferromagnetic circuit and generate a main magnetic flux that traverses the gap (T) in the transverse direction (V), - A coil (40) located in the gap (T), coaxial with the longitudinal axis (X), and movable along a direction of movement (M) parallel to the longitudinal axis (X) so as to move the active radiator (30), A loudspeaker (1) comprising a secondary magnet (50) located at the first end (21A) of the central core (21) such that it is aligned with the longitudinal axis (X) and crosses the gap (T) in the transverse direction (V) to generate a secondary magnetic flux that closes itself outside the ferromagnetic circuit.

2. The loudspeaker (1) according to claim 1, wherein the auxiliary magnet (50) is in contact with the first end (21A) of the central core (21) either directly or through a region of high magnetic permeability.

3. The outer core (22) is further separated from the second end (21B) of the central core (21) to define an additional gap (T') that extends longitudinally and is aligned with the gap (T), and the main magnetic flux traverses the additional gap (T') in an additional transverse direction, and the loudspeaker (1) An additional auxiliary magnet (50') is located at the second end (21B) of the central core (21) so as to be aligned with the longitudinal axis (X) and to generate an additional auxiliary magnetic flux that traverses the additional gap (T') in the additional transverse direction and closes itself outside the ferromagnetic circuit, The loudspeaker (1) according to claim 1 or 2, comprising an additional coil (40') located in the additional gap (T'), coaxial with the longitudinal axis (X), and movable along an additional direction of movement (M') parallel to the longitudinal axis (X).

4. The loudspeaker (1) according to any one of claims 1 to 3, wherein the central core (21) has a cylindrical hole (F) extending along the longitudinal axis (X) between the inlet of the second end (21B) of the central core (21) and the outlet of the first end (21A), and the central core (21) is cylindrically symmetric with respect to the longitudinal axis (X).

5. The loudspeaker (1) according to claim 4, comprising a power cable (80) configured to connect an amplifier to the coil (40), wherein the cylindrical hole (F) defines a passage for the power cable (80) from the inlet to the outlet of the cylindrical hole (F).

6. A light diffuser (81) is located at the outlet of the cylindrical hole (F) and protrudes toward the active radiator (30), A light source (82) is located at the entrance of the cylindrical hole (F) and configured to generate light, The loudspeaker (1) according to claim 4 or 5, further comprising: an optical guide (84) configured to connect the light source (82) to an optical diffuser (81) in order to diffuse the light generated by the light source (82) toward the active radiator (30).

7. The loudspeaker (1) according to any one of claims 1 to 6, wherein the polarization of the main magnet (23) and the polarization of the auxiliary magnet (50) coincide in the longitudinal direction.

8. The loudspeaker (1) according to any one of claims 1 to 7, wherein the coil (40) has a longitudinal range smaller than the longitudinal range of the gap (T).

9. The loudspeaker (1) according to any one of claims 1 to 8, wherein the outer core (22) comprises an upper (22A) and a lower (22B) aligned longitudinally with respect to each other, and the main magnet (23) is located between the upper (22A) and the lower (22B) in a direction parallel to the longitudinal axis (X), and the upper (22A) is ring-shaped and has an inner surface that extends around the longitudinal axis (X) and faces the longitudinal axis (X).

10. The area S of the inner surface of the upper part (22A) of the outer core (22) ｔｐ and the surface area S of the radially extending central core (21) ｐｐ The loudspeaker (1) according to claim 9, wherein the ratio to is 1.6 or less.

11. Height H of the inner surface of the upper part (22A) of the outer core (22) ｐｐ and the height H of the main magnet (23) ｍ The loudspeaker (1) according to claim 9 or 10, wherein the ratio to is measured in the longitudinal direction and is 1.7 or less.

12. Height H of the inner surface of the upper part (22A) of the outer core (22) ｐｐ and the height H of the coil (40) ｖｃ The ratio to is measured in the longitudinal direction and is different from 1, the loudspeaker (1) according to any one of claims 9 to 11.

13. - The coil (40) extends longitudinally between a first end proximal to the radiator (30) and a second end opposite to the first end, and the coil (40) is configured such that the first end moves within the gap (T) such that it moves between a point of maximum movement of the radiator (30) away from the central core (21) and a point of minimum movement of the radiator (30) toward the central core (21), and as it moves between the maximum and minimum points, the first end (or the second end) of the coil (40) passes through a point of equilibrium. - Height H of the inner surface of the upper part (22A) of the outer core (22) ｐｐ and the distance X between the equilibrium point and the maximum point ｍａｘ The loudspeaker (1) according to any one of claims 9 to 12, wherein the ratio to is 1.6 or less.

14. Comprising a basket (70) and a suspension (31), the radiator (30) is fixed to the basket (70) via the suspension (31), and the diameter D of the suspension (31) ｄ and the diameter D of the main magnet (23) ｍ The ratio of which is 1.13 or less, the loudspeaker (1) according to any one of claims 1 to 13.

15. A method of amplifying sound, - A step of providing an active radiator (30) that is movable along a longitudinal axis (X) to generate sound waves, - A ferromagnetic circuit, A central core (21) extends along the longitudinal axis (X) from a first end (21A) near the proximal end of the active radiator (30) to a second end (21B) near the distal end of the active radiator (30), An outer core (22) located outside the central core (21), surrounding the longitudinal axis (X) and defining a longitudinally extending gap (T), and separated from the first end (21A) of the central core (21), The steps include providing a ferromagnetic circuit including a main magnet (23) having a ring shape and being inserted into the outer core (22), and having longitudinally oriented polarization; - The step of providing a coil (40) located in the gap (T) and coaxial with the longitudinal axis (X), - A step of generating a main magnetic flux that circulates through the ferromagnetic circuit so as to traverse the gap (T) in the transverse direction (V) via the main magnet (23), - The steps include moving the coil (40) along a direction of movement (M) parallel to the longitudinal axis (X) in accordance with the generated magnetic flux, and moving the active radiator (30), The amplification method includes the step of generating a secondary magnetic flux that crosses the gap (T) in the transverse direction (V) and closes itself outside the ferromagnetic circuit, such that the total magnetic flux density crossing the gap (T) is greater than the density of the main magnetic flux.

16. The method according to claim 15, comprising the step of providing a secondary magnet (50) that is aligned with the longitudinal axis (X) and located at the first end (21A) of the central core (21).

17. The method according to claim 16, wherein the auxiliary magnet (50) is in direct contact with the first end (21A) of the central core (21) or via a region of high permeability.

18. The method according to claim 16 or 17, comprising the step of simultaneously magnetizing the main magnet (23) inserted in the outer core (22) and the auxiliary magnet (50) located at the first end (21A) of the central core (21).

19. The outer core (22) is separated from the central core (21) so as to define an additional gap (T') that extends longitudinally and is aligned with the gap (T), and the main magnetic flux traverses the additional gap (T') in an additional transverse direction, and the method, - The step of providing an additional coil (40') located in the additional gap (T') and coaxial with the longitudinal axis (X), - A step of moving the additional coil (40') along an additional direction of movement (M') parallel to the longitudinal axis (X) in accordance with the generated magnetic flux, The method according to any one of claims 15 to 18, comprising the step of generating an additional secondary magnetic flux that traverses the additional gap (T') in the additional transverse direction and closes itself outside the ferromagnetic circuit, wherein the total magnetic flux density traversing the additional gap (T') is greater than the density of the main magnetic flux.

20. The method according to claim 19, comprising the step of providing an additional auxiliary magnet (50') located at the second end (21B) of the central core (21) and aligned with the longitudinal axis (X).

21. The method according to any one of claims 15 to 20, wherein the coil (40) has a longitudinal range smaller than the longitudinal range of the gap (T).

Images