Linear motor magnet assembly and loudspeaker unit

Abstract

A linear motor magnet assembly (2) for use in a loudspeaker unit (1), having a fixed base actuator component (4) and a membrane actuating element (5), wherein the membrane actuating element (5) has a linear deviation axis (A). A first auxiliary magnetic element (7) and a second auxiliary magnetic element (8) exist, wherein the first auxiliary magnetic element (7) provides a first auxiliary spatial magnetic field having a main axis aligned with the linear deviation axis (A). The second auxiliary magnetic element (8) is fixedly connected to the membrane actuating element (5) of the linear motor magnet assembly (2) and has a second auxiliary spatial magnetic field, wherein the second auxiliary magnetic field overlaps with the first auxiliary spatial magnetic field and is oriented substantially similarly to the first auxiliary spatial magnetic field over a first predetermined deviation range (E1) of the linear motor magnet assembly (2).

Description

Technology Field

[0001] The present invention relates to a linear motor magnet assembly for use in a loudspeaker unit, wherein the linear motor magnet assembly comprises a fixed base actuator component and a membrane operating element, and the membrane operating element has a linear deviation axis. Background Technology

[0002] Such a linear motor magnet assembly is disclosed in International Patent Publication WO2018 / 057814, which discloses, for example, a loudspeaker unit comprising a membrane and a plurality of driving units for driving the membrane. The problem to be solved

[0003] The present invention is to provide a linear motor magnet assembly for use in a loudspeaker unit that can improve the performance of a linear motor actuator system.

[0004] According to the present invention, a linear motor magnet assembly as described above is provided, having a fixed base actuator component and a membrane actuating element, wherein the membrane actuating element has a linear deviation axis. A first auxiliary magnetic element and a second auxiliary magnetic element exist, wherein the first auxiliary magnetic element provides a first auxiliary space magnetic field having a principal axis aligned with the linear deviation axis of the linear motor magnet assembly. The second auxiliary magnetic element is fixedly connected to the membrane actuating element of the linear motor magnet assembly and has a second auxiliary space magnetic field, wherein the second auxiliary space magnetic field overlaps with the first auxiliary space magnetic field and is oriented substantially similarly to the first auxiliary space magnetic field over a first predetermined deviation range of the linear motor magnet assembly.

[0005] The first auxiliary magnetic element and the second auxiliary magnetic element are positioned so that when the linear motor magnet assembly moves, the coupling force generated by the first auxiliary magnetic element and the second auxiliary magnetic element amplifies the motor movement. Accordingly, the present invention provides an energy-efficient and improved linear movement system by reducing the stiffness with respect to excursion of the linear motor. This effectively reduces the power required by the linear motor system to achieve complete excursion. Additional embodiments are described by dependent claims and are explained with reference to exemplary embodiments illustrated in the drawings. Brief explanation of the drawing

[0006] The present invention will be described in more detail below with reference to the attached drawings. FIGS. 1a and 1b illustrate an example of a permanent magnet auxiliary structure in two operating situations according to a first embodiment of a linear magnet motor assembly of the present invention. FIG. 2a shows a perspective view of a loudspeaker unit having two opposing membranes, each driven by two linear motor magnet assemblies according to another embodiment. FIG. 3 shows a cross-sectional view of a linear motor magnet assembly according to another embodiment of the present invention. Specific details for implementing the invention

[0007] The present invention relates to a linear motor magnet assembly (also referred to herein as an actuator amplification device or a permanent magnet auxiliary device) comprising a combination of permanent magnets using a magnetic field to assist and amplify motion generated by a linear motor actuator, and comprising the application of features corresponding to nonlinearity in the stiffness of the entire loudspeaker device using a combination of a linear motor and a permanent magnet auxiliary device.

[0008] The present invention may be applied to various forms of loudspeaker units (1), such as examples described and disclosed in Patent Publication WO2018 / 0596814, and unpublished PCT / NL2018 / 050263, PCT / EP2018 / 0779509, PCT / EP2019 / 055831 and EP19162460.0 from the same applicant. The linear motor magnet assembly (2) may be implemented according to any of the exemplary embodiments described herein.

[0009] Electrodynamic transducers generally consist of a linear motor, a membrane, and the suspension of the linear motor. Transducers for intermediate and low-frequency responses are typically mounted in an enclosure. Mounting the transducer in an enclosure (which can be, for example, sealed or ported) increases the total stiffness of the suspension that needs to be overcome by the linear motor. An electrodynamic transducer system capable of providing a low-frequency response (10 Hz - 200 Hz) in a sealed or ported enclosure will generally have stiffness resulting from the transducer's own suspension as well as stiffness resulting from air compression inside the enclosure. Air compression-induced stiffness increases when the membrane needs to compress air; the higher the required compression, the higher the stiffness. The transducer's own suspension stiffness will need to increase as the air-induced stiffness increases to prevent unwanted deformation of the suspension caused by the air-induced stiffness. Consequently, the linear motor actuator will require an increased power input to generate the desired air compression. Ideally, to produce an electrodynamic transducer with the lowest distortion caused by the nonlinearity of stiffness when placed in a sealed or ported enclosure, one will attempt to achieve the lowest possible increase in stiffness caused by or required by the effects arising from the enclosure. The transducer will ideally behave as if it were free air.

[0010] The present invention provides a device using a combination of at least two permanent magnets to improve the performance of a linear motor actuator system by reducing stiffness over a full range of displacement of the linear motor, thereby effectively reducing the power required by the linear motor system and enabling movement through the range of displacement.

[0011] FIGS. 1a and 1b illustrate examples of a linear motor magnet assembly (2) or a part of a permanent magnet auxiliary structure in two operating situations. These exemplary embodiments include an axially magnetized magnet, and the second auxiliary magnetic element (8) is a ring-shaped magnet that moves around the first auxiliary magnetic element (7), which is a cylinder-shaped magnet.

[0012] The present invention provides an improved linear motor magnet assembly for use in a loudspeaker unit that requires less power than is required by a linear motor system to create linear motor deviation. Accordingly, the present invention provides a cost-effective and power-efficient system that requires less structural modification of the system.

[0013] FIG. 2a illustrates a cross-sectional view, FIG. 2b illustrates a perspective view of an exemplary embodiment of the present invention having two opposing membranes (3) each driven by a linear motor magnet assembly (2), and an embodiment of the present invention is implemented.

[0014] A linear motor magnet assembly (2) is applied for use, for example, in a loudspeaker unit (1). The linear motor magnet assembly (2) includes a fixed base actuator element (4) and a membrane actuating element (5). The fixed base actuator component (4) consists of two axially aligned magnetic elements (7, 7) that are part of the linear motor magnet assembly (2). * ) is mechanically connected. The material of the fixed base actuator component (4) consists of two axially aligned magnetic elements (7, 7 *It is a non-magnetic material that ensures a suitable magnetic field distribution for interlocking between the membrane operating element (5). The membrane operating element (5) is movable and has a linear deviation axis (A), that is, the direction in which the membrane (3) moves up and down. When operated, the membrane operating element (5) moves the linear motor magnetic assembly (2) connected to the membrane (3). Thus, the membrane (3) moves up and down according to the direction of operation. Two opposing membranes (3) are separated by a predetermined distance. The linear motor magnetic assembly (2) is a first auxiliary magnetic element (7) (two axially aligned magnetic elements (7, 7 * It further includes one of the) and a second auxiliary magnetic element (8). The first auxiliary magnetic element (7) provides a first auxiliary space magnetic field having a main axis aligned with the linear deviation axis (A) of the linear motor magnet assembly (2). The second auxiliary magnetic element (8) is fixedly connected to the membrane operating element (5) of the linear motor magnet assembly (2) and has a second auxiliary space magnetic field. The second auxiliary magnetic field overlaps with the first auxiliary space magnetic field and is oriented substantially similarly to the first auxiliary space magnetic field through the first predetermined deviation range (E1) of the linear motor magnet assembly (2).

[0015] An embodiment of the present invention of a loudspeaker unit (1) has two opposing membranes (3) disposed on the upper and lower surfaces of the loudspeaker unit (1). Although the loudspeaker unit (1) is depicted as a rectangular unit in FIGS. 2a and 2b, this is not a limiting geometric shape. The base element of each membrane (3) is structurally connected to two linear motor magnetic assemblies (2) at two of the diagonal ends of the membrane (3). As shown in FIG. 2b, the base element of the lower membrane (3) is structurally connected by two different linear motor magnetic assemblies (2) located at both of the lower diagonal ends of the membrane. Similarly, the base element of the upper membrane (3) is structurally connected by two different linear motor magnetic assemblies (2) located at both of the upper diagonal ends of the membrane. The effect of the combination of these features is an increasing magnetic force (or reduced stiffness) in the direction of deviation within a first predetermined deviation range, that is, the first and second auxiliary magnetic elements help overcome the suspension force and air compression force within the loudspeaker unit (1). The second auxiliary magnetic element (8) is attached to the membrane operating element (5) using a holder body, for example, as shown in the cross-sectional view of FIG. 2a. The fixed connection does not necessarily imply a direct physical attachment of these two elements to each other.

[0016] In another embodiment, the second auxiliary magnetic element (8) is located at a first distance along the linear deviation axis (A) from the membrane operating element (5). FIG. 1a illustrates an operating situation in which the second auxiliary magnetic element (8) is located at the center of the first auxiliary magnetic element (7) along the linear deviation axis (A). FIG. 1b also illustrates an operating situation in which the second auxiliary magnetic element (8) is located away from the center of the first auxiliary magnetic element (7) along the linear deviation axis (A).

[0017] Another embodiment of the present invention relates to a linear motor magnet assembly (2) in which the second auxiliary space magnetic field and the first auxiliary space magnetic field partially overlap over the second predetermined deviation range (E2) of the linear motor magnet assembly (2). This feature will result in a force that decreases in the direction of deviation in the second predetermined deviation range (E2). In the exemplary embodiments of FIGS. 1a and 1b, the first auxiliary magnetic element (7) has finite dimensions along the axis (A), and the second predetermined deviation range (E2) extends beyond the first predetermined deviation range (E1).

[0018] According to another embodiment of the present invention, a linear motor magnet assembly (2) is provided, and a first auxiliary magnetic element (7) is fixedly connected to a fixed base actuator element (4) of the linear motor magnet assembly (2). The fixed connection does not necessarily imply direct attachment or structural connection between the two elements. This may be, for example, a simple magnetic connection or a magnetic connection by levitation.

[0019] Another embodiment of the present invention relates to a linear motor magnet assembly (2) comprising a suspension assembly (6) connected to a membrane operating element (5) and a fixed base actuator component (4), wherein the suspension assembly (6) allows mutual movement between the membrane operating element (5) and the fixed base actuator component (4) along a linear deviation axis (A) and is positioned to form a resting position of the membrane operating element (5) (and a second auxiliary magnetic element (8) fixedly connected thereto) along the linear deviation axis (A).

[0020] The present invention further provides a linear motor magnet assembly for use in a loudspeaker unit by using a combination of at least two permanent magnets to improve the performance of a linear motor actuator system by reducing stiffness over a full displacement of the linear motor, thereby effectively reducing the power required by the linear motor system to create a full displacement. Embodiments of the present invention also relate to a linear motor actuator amplification device (or permanent magnet auxiliary device) comprising a combination of permanent magnets using a magnetic field to assist and amplify motion generated by a linear motor actuator, and the application of features corresponding to nonlinearity in the stiffness of the full system by using a combination of a linear motor and a permanent magnet auxiliary device.

[0021] According to one embodiment, the present invention relates to a linear motor magnet assembly (2), wherein a second auxiliary magnetic element (8) comprises a permanent magnetic material. Another embodiment of the present invention relates to a linear motor magnet assembly (2), wherein the second auxiliary magnetic element (8) comprises an electromagnet. In such a system, the second auxiliary magnetic element (8) is electrically magnetized, for example, for a specific period of time. In a similar manner, another embodiment of the present invention relates to a linear motor magnet assembly (2), wherein a first auxiliary magnetic element (7) comprises a permanent magnetic material. Yet another embodiment of the present invention relates to a linear motor magnet assembly (2), wherein the first auxiliary magnetic element (7) comprises an electromagnet.

[0022] According to another embodiment of the present invention, a linear motor magnet assembly (2) or a motor auxiliary unit is provided, wherein the auxiliary unit comprises at least two permanent magnets (7, 8). One magnet is attached to the static part of the linear motor actuator system. The other of the at least two magnets (7, 8) is attached to the stationary part of the aforementioned linear motor actuator system. The magnets (7, 8) are positioned so that when the linear motor actuator moves, the forces generated by the combined moving and auxiliary magnetic fields of the static magnets (7, 8) amplify the motor movement. The architecture of the permanent magnet auxiliary unit determines the total force and change in the reaction force for the deviation of the permanent magnet system corresponding to the stiffness of the linear motor system. The structure and mutual element orientation of the present invention make it possible to provide a more energy-efficient linear movement system.

[0023] An exemplary embodiment relates to a permanent magnet structure that can be used in combination with a linear motor actuator system, wherein at least one of two permanent magnets is attached to a moving part of the linear motor actuator system and at least one permanent magnet is attached to a static part of the linear motor actuator system, and said permanent magnets are arranged in such a way that the combined magnetic field of the permanent magnets of the permanent magnet system corresponds to an increasing stiffness for deviation of the linear motor actuator system.

[0024] In another embodiment, a permanent magnet structure and a linear motor actuator system are provided in combination with a suspension that returns the moving part of the linear motor actuator to a static resting position, said suspension is caused by a suspension device or mechanical stiffness caused by air or fluid pressure.

[0025] The present invention also relates to a permanent magnet structure and a linear motor actuator system applied to a loudspeaker unit, wherein the permanent magnet is on the membrane of the loudspeaker unit and static magnets are placed above and below the membrane.

[0026] Another embodiment of the present invention relates to a linear motor magnet assembly (2), wherein a first auxiliary magnetic element (7) is formed integrally with a fixed base actuator component (4). This results in lower cost and easier manufacturing as the linear motor magnet assembly has one fewer structural element (shared component). The first auxiliary magnetic element (7) comprises a permanent magnet material or an electromagnet material.

[0027] An exemplary embodiment of the present invention relates to a linear motor magnet assembly (2), wherein the first auxiliary magnetic element (7) is an axially magnetized permanent magnet in the shape of a cylinder (or rod) (having opposing magnetic poles (7a, 7b) at its outer end, as shown in the exemplary embodiment illustrated in FIG. 1a and 1b). Another embodiment of the present invention relates to a linear motor magnet assembly (2), wherein the second auxiliary magnetic element (8) is ring-shaped, having axially aligned magnetic poles (8a, 8b) having a center hole larger than the maximum cross-sectional diameter of the first auxiliary magnetic element (7). With this geometric shape, the first auxiliary magnetic element (7) can be positioned within the second auxiliary magnetic element (8) at different operating positions.

[0028] Another embodiment of the present invention relates to a linear motor magnet assembly (2), wherein a first auxiliary magnetic element (7) has a predetermined shape to provide a first auxiliary spatial magnetic field profile that is predetermined over a range of deviation of the linear motor magnet assembly (2). Another embodiment of the present invention relates to a linear motor magnet assembly (2), wherein the predetermined shape is a double (e.g., truncated) cone shape having a maximum diameter in the middle portion of the first auxiliary magnetic element (7). This can be implemented by having one of the magnets as a cone-shaped magnet, the shape of which generates a magnetic field of varying strength over the deviation. This allows for more efficient control of the relative movement of the second auxiliary magnetic element (8) with respect to the first auxiliary magnetic element (7) by taking into account the varying strength of the magnetic field.

[0029] FIG. 3 illustrates a cross-sectional view of a linear motor magnet assembly according to another embodiment of the present invention, comprising two opposing magnetic bodies (7') forming a first auxiliary magnetic element and a magnetic body (8') positioned between them forming a second auxiliary magnetic element. The two magnetic bodies may be of a similar type of magnetization, for example, both may be permanent magnets or both may be electromagnets. Alternatively, the two magnetic bodies (7') may be magnetized in different ways, for example, one of them may be a permanent magnet and the other may be an electromagnet.

[0030] The dimensions and shapes of the first auxiliary magnetic element and the second auxiliary magnetic element may differ. For example, the first auxiliary magnetic element may have a flat shape or a disk shape. The second auxiliary magnetic element may have a disk shape or a ring shape. Additionally, the sizes of the first auxiliary magnetic element and the second auxiliary magnetic element may differ. As described above, another embodiment of the present invention relates to a linear motor magnet assembly (2), wherein the first auxiliary magnetic element (7) comprises two (e.g., permanent) magnetic bodies (7) (e.g., flat shape or disk shape) at a predetermined distance from each other along a linear deviation axis (A), and the second auxiliary magnetic element (8) comprises an axially magnetized magnetic body (8') (e.g., disk shape or ring shape) located between the two magnetic bodies (7'). Due to the presence of two magnetic bodies (7'), the second auxiliary space magnetic field and the first auxiliary space magnetic field partially overlap in the symmetrical direction over the second predetermined deviation range (E2) of the linear motor magnet assembly (2). This feature will further reduce the force in the deviation direction in the second predetermined deviation range (E2).

[0031] Another embodiment of the present invention relates to a linear motor magnet assembly (2), comprising two axially aligned magnetic elements (7, 7) having a main space magnetic field having a main axis aligned with the linear deviation axis (A) of the linear motor magnet assembly (2). * The membrane operating element (5) further includes a voice coil, said voice coil is positioned to generate a coil magnetic field that interacts with the main space magnetic field to move the voice coil along the linear deviation axis (A) (i.e., to drive the membrane (3)).

[0032] Another embodiment of the present invention relates to a loudspeaker unit (1) comprising a membrane (3) and a linear motor magnet assembly (2), wherein a membrane operating element (5) and a second auxiliary magnetic element (8) are fixedly connected to the membrane (3).

[0033] The present invention has been described above with reference to a number of exemplary embodiments illustrated in the drawings. Modifications of some parts or elements and alternative implementations are possible and are included within the scope of protection as defined in the appended claims.

Claims

Claim 1 A linear motor magnet assembly (2) for use in a loudspeaker unit, wherein the linear motor magnet assembly (2) comprises: a voice coil (5) configured to move axially along a linear excursion axis (A); and first and second magnetic elements (7, 7') aligned along the linear excursion axis (A) and having first and second magnetic fields, respectively; A linear motor magnet assembly comprising a third magnetic element (8) having a third magnetic field and fixedly connected to the voice coil (5), wherein the voice coil (5) generates a coil magnetic field interacting with the first and second magnetic fields so that when the voice coil (5) moves axially along the linear deviation axis (A) around the first and second magnetic elements (7, 7'), the third magnetic element (8) is configured to overlap at least partially with the first and second magnetic elements (7, 7'), and the voice coil (5) is configured to move along the linear deviation axis (A) when operated by the linear motor magnet assembly, and the movement of the voice coil is amplified based on the interaction of the first and second magnetic fields with the third magnetic field. Claim 2 In claim 1, the third magnetic element (8) is a linear motor magnet assembly located at a first distance along the linear deviation axis (A) from the voice coil (5). Claim 3 A linear motor magnet assembly according to claim 1, wherein the first and second magnetic fields overlap over a first predetermined deviation range (E1) of the linear motor magnet assembly (2), and the first and second magnetic fields partially overlap over a second predetermined deviation range (E2) of the linear motor magnet assembly (2). Claim 4 In claim 1, the first magnetic element (7) is fixedly connected to the fixed base actuator component (4) of the linear motor magnet assembly (2), the linear motor magnet assembly. Claim 5 A linear motor magnet assembly according to claim 4, further comprising a suspension assembly (6) connected to the voice coil (5) and the fixed base actuator component (4), wherein the suspension assembly (6) allows mutual movement between the voice coil (5) and the fixed base actuator component (4) along the linear deviation axis (A) and is positioned to form a resting position of the voice coil (5) along the linear deviation axis (A). Claim 6 In claim 1, the third magnetic element (8) comprises one or more of a permanent magnetic material and an electromagnet, forming a linear motor magnet assembly. Claim 7 In claim 1, the first magnetic element (7) comprises at least one of a permanent magnetic material and an electromagnet, forming a linear motor magnet assembly. Claim 8 In paragraph 4, the first magnetic element (7) is a linear motor magnet assembly formed integrally with the fixed base actuator component (4). Claim 9 In claim 1, the first magnetic element (7) is a linear motor magnet assembly in which the first magnetic element is a permanent magnet axially magnetized in a cylindrical shape. Claim 10 In claim 9, the third magnetic element (8) is a ring-shaped linear motor magnet assembly having axially aligned magnetic poles (8a, 8b) having a center hole larger than the maximum cross-sectional diameter of the first magnetic element (7). Claim 11 A linear motor magnet assembly having a predetermined shape configured to provide a first auxiliary space magnetic field profile over a deviation range of the linear motor magnet assembly (2), wherein the first magnetic element (7) is a linear motor magnet assembly. Claim 12 In claim 11, the linear motor magnet assembly, wherein the predetermined shape is a double cone shape having the largest diameter in the middle portion of the first magnetic element (7). Claim 13 A linear motor magnet assembly according to claim 1, wherein the first magnetic element (7) comprises two magnetic bodies (7') at predetermined distances from each other along the linear deviation axis (A), and the third magnetic element (8) comprises an axially magnetized magnetic body (8') located between the two magnetic bodies (7'). Claim 14 A loudspeaker unit (1) comprising a membrane (3) and a linear motor magnet assembly (2) according to claim 1, wherein the voice coil (5) and the third magnetic element (8) are fixedly connected to the membrane (3). Claim 15 delete Claim 16 delete Claim 17 delete

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