Transducer Assembly

Abstract

A loudspeaker transducer assembly is provided that is configured to provide a substantially constant electromagnetic force coefficient when driven distally and proximal to the upper surface. [Solution] The transducer assembly 100 includes two coil sections 110, 112 and two magnetic gaps 120, 122 separated by a region of greater magnetic resistance, such that when one coil section moves out of the magnetic gap while being driven axially, the other coil section moves into the magnetic gap to provide a substantially constant speaker force coefficient. The other coil section continues to move from its stationary position through its proximal magnetic gap into the distal magnetic gap, thereby providing an extended useful linear stroke by sequentially using both magnetic gaps.

Description

Technical Field

[0001] In some aspects, the present disclosure relates to a transducer including a loudspeaker transducer having a distributed coil.

Background Art

[0002] The force factor of a speaker, which can be represented by BL, is a parameter indicating the strength of a loudspeaker motor. The force factor of a speaker is the product of the magnetic flux density (B) in tesla and the length (L) in meters of the voice coil in the magnetic gap of the loudspeaker motor. As the voice coil enters and exits the magnetic gap, the force factor of the speaker can change. The calculated force factor of the speaker can serve as a surrogate for describing the available driving force induced by the voice coil at the position where a current of 1 ampere flows through the voice coil.

[0003] Note that as documents related to this technical field, Patent Documents 1 and 2 exist.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

[0005] This specification discloses transducer assemblies (e.g., loudspeaker motors, voice coil motors) having two or more coil portions (e.g., coils, coil bodies, windings) and two or more magnetic gaps (e.g., air gaps). The coil portions and magnetic gaps of the transducer assembly can be configured to ensure that the force coefficient of the speaker remains substantially consistent over long displacements without significantly shifting the vibrating system mass, which may be desirable for small, high-performance low-frequency loudspeakers and / or other applications.

[0006] Two or more coil sections can carry current in the same direction. Two or more coil sections can be spaced apart from each other axially along a former positioned around a pole piece. Two or more magnetic gaps can have magnetic flux in the same direction due to regions of greater magnetoresistance between adjacent magnetic gaps. When a first coil section moves out of a first magnetic gap, a second coil section can move into a second magnetic gap, thereby providing a stable (e.g., substantially consistent) BL product. When the transducer assembly is driven in a first direction, with the first coil section outside the first magnetic gap, the second coil section can continue to move into the first magnetic gap through regions of greater magnetoresistance, thereby providing a stable BL product. Similarly, when the transducer assembly is driven in a second direction, with the second coil section outside the second magnetic gap, the first coil section can continue to move into the second magnetic gap through regions of greater magnetoresistance, thereby providing a stable BL product. Accordingly, the transducer assemblies disclosed herein can provide substantially the same BL product when the transducer assembly is driven in the first and second directions.

[0007] Various transducer assemblies are disclosed herein. A transducer assembly may include a pole piece. A transducer assembly may include a former positioned around the pole piece. A transducer assembly may include a first coil portion and / or a second coil portion positioned on the former. The first coil portion and the second coil portion may be spaced apart from each other in the axial direction. Current may flow in the same direction with respect to the cross-section of the first coil portion and the second coil portion. A transducer assembly may include a magnetic structure positioned around the pole piece. The magnetic structure may include a magnet (e.g., a permanent magnet or electromagnet), a first plate, and / or a second plate. The first plate may provide a first magnetic gap having an axial gap length. The second plate may provide a second magnetic gap having the same axial gap length. The first plate and the second plate cooperate to provide a region between the first magnetic gap and the second magnetic gap in which the magnetoresistance is greater than that in the first magnetic gap and the second magnetic gap. Each of the first and second coil sections may have an axial coil length that is approximately equal to the sum of the axial length of the region with greater magnetic resistance and the axial gap length of the first or second magnetic gap. The first coil section may occupy approximately half of the axial gap length of the first magnetic gap. When the transducer assembly is stationary, the second coil section may occupy approximately half of the axial gap length of the second magnetic gap. The transducer assembly may have a speaker force coefficient that is substantially consistent over most of the stroke.

[0008] In some variations, the second plate may be positioned axially between the first plate and the magnet.

[0009] In some variations, the radial distance between the pole piece and the first and second plates in the first and second magnetic gaps can be smaller than the radial distance between the pole piece and the first and second plates in regions where the magnetoresistance is greater.

[0010] In some variations, at least one of the first plate and the second plate may have radial recesses in a region where the magnetoresistance is greater.

[0011] In some variations, the recess is a notch.

[0012] In some variations, the first coil portion and the second coil portion may be wound around the mandrel in the same coil direction.

[0013] In some variations, the first magnetic gap may be radially positioned between the pole piece and the portion of the first plate closest to the pole piece.

[0014] In some variations, a second magnetic gap may be radially positioned between the pole piece and the portion of the second plate closest to the pole piece.

[0015] Transducer assemblies in several variations are disclosed herein. A transducer assembly may include a pole piece. A transducer assembly may include a former disposed around the pole piece. A transducer assembly may include a first coil portion and a second coil portion disposed on the former. The first coil portion and the second coil portion may be spaced apart from each other in the axial direction. The first coil portion and the second coil portion may be wound in the same direction with respect to the cross section. A transducer assembly may include a magnetic structure disposed around the pole piece. The magnetic structure may include a magnet, a first plate providing a first magnetic gap having a first axial gap length, a second plate providing a second magnetic gap having a second axial gap length, and / or a region having greater magnetoresistance than the magnetoresistance in the first and second magnetic gaps. The region having greater magnetoresistance may be located between the first and second magnetic gaps. When the transducer assembly is stationary, the first coil portion can occupy approximately half of the first axial gap length of the first magnetic gap, and the second coil portion can occupy approximately half of the second axial gap length of the second magnetic gap.

[0016] In some variations, a portion of the first plate is positioned radially outward from the second plate.

[0017] In some variations, the radial distance between the pole piece and the first plate in the first magnetic gap can be smaller than the radial distance between the pole piece and the first plate in the region where the magnetoresistance is greater.

[0018] In some variations, the first plate may have radial recesses in regions where the magnetoresistance is greater.

[0019] In some variations, the first magnetic gap may be radially positioned between the pole piece and the portion of the first plate closest to the pole piece.

[0020] In some variations, a second magnetic gap may be radially positioned between the pole piece and the portion of the second plate closest to the pole piece.

[0021] Several variations of transducer assemblies are disclosed herein. A transducer assembly may include a central ferromagnetic component. A transducer assembly may comprise a closed-shaped tubular member arranged around the central ferromagnetic component. A transducer assembly may comprise a first conductive coil portion and a second conductive coil portion arranged on the tubular member. The first conductive coil portion and the second conductive coil portion may be spaced apart from each other in the axial direction. The first conductive coil portion and the second conductive coil portion may be wound in the same coil direction. A transducer assembly may comprise a magnetic structure arranged around the central ferromagnetic component. The magnetic structure may comprise a magnet, a first ferromagnetic element providing a first magnetic gap having a first axial gap length, a second ferromagnetic element providing a second magnetic gap having a second axial gap length, and / or a region having greater magnetoresistance than the magnetoresistance in the first and second magnetic gaps. Regions with higher magnetoresistance can be located between the first magnetic gap and the second magnetic gap.

[0022] In some variations, the radial distance between the central ferromagnetic component and the first ferromagnetic element in the first magnetic gap can be smaller than the radial distance between the central ferromagnetic component and the first ferromagnetic element in the region of greater magnetoresistance.

[0023] In some variations, the first ferromagnetic element may have radial recesses in the region where magnetoresistance is greater.

[0024] In some modified examples, the first conductive coil portion can have an axial coil length that is substantially equal to the total axial length of the first axial gap length and the region with a larger magnetoresistance.

[0025] In some modified examples, the first magnetic gap can be arranged radially between the central ferromagnetic component and the portion of the first ferromagnetic element closest to the central ferromagnetic component. The second magnetic gap can be arranged radially between the central ferromagnetic component and the portion of the second ferromagnetic element closest to the central ferromagnetic component.

[0026] In some modified examples, the tubular member can move freely over a certain distance in response to the electrical signals applied to the first conductive coil portion and the second conductive coil portion.

[0027] The accompanying drawings are exemplary embodiments and do not present all possible embodiments of the present disclosure. The illustrated embodiments are intended to illustrate the scope of protection but not to limit the scope of protection. Various features of the different disclosed embodiments can be combined to form further embodiments, which are part of the present disclosure.

Brief Description of the Drawings

[0028] [Figure 1A]The diagram shows half of a cross-sectional view of a transducer assembly for a loudspeaker in a stationary state. Here, the transducer assembly includes a yoke having a pole piece, a first magnet, a first plate, a second plate, a first magnetic gap between the pole piece and the first plate, a second magnetic gap between the pole piece and the second plate, a region of greater magnetoresistance between the first and second magnetic gaps, and a former positioned around the pole piece on which the first and second coil portions are positioned. As shown, the first coil portion is positioned along approximately 50% of the axial length of the first magnetic gap, and the second coil portion is positioned along approximately 50% of the axial length of the second magnetic gap. [Figure 1B] Figure 1A shows the transducer assembly of Figure 1A being driven in a first direction from the configuration shown in Figure 1A. The first coil portion is positioned substantially completely out of the first magnetic gap, and the second coil portion is positioned along substantially the entire axial length of the second magnetic gap. [Figure 1C] Figure 1B shows the transducer assembly of Figure 1A, which continues to drive in the first direction from the configuration shown in Figure 1B. The first coil portion is positioned completely out of the first magnetic gap, and the second coil portion is positioned along approximately 50% of the axial length of the second magnetic gap, the entire axial length of the region with greater magnetoresistance, and approximately 50% of the axial length of the first magnetic gap. [Figure 1D] Figure 1C shows the transducer assembly of Figure 1A, which continues to drive in a first direction from the configuration shown in Figure 1A. The first coil portion is positioned substantially completely out of the first magnetic gap, and the second coil portion is positioned along substantially the entire axial length of the region where the magnetoresistance is greater, and substantially the entire axial length of the first magnetic gap. [Figure 1E]Figure 1D shows the transducer assembly of Figure 1A, which is continuously driven in a first direction from the configuration shown in Figure 1D. The first coil portion is positioned completely out of the first magnetic gap, and the second coil portion is positioned along approximately 70% of the axial length of the first magnetic gap. [Figure 2A] Figure 1A shows the transducer assembly driven in the second direction. After moving in the second direction by reversing the configuration shown in Figures 1D, 1C, 1B, and 1A from the configuration shown in Figure 1E, the first coil portion is positioned substantially along the entire axial length of the first magnetic gap, and the second coil portion is positioned substantially outside the second magnetic gap. [Figure 2B] Figure 1A shows the transducer assembly driven in a second direction from the configuration shown in Figure 2A. The first coil portion is positioned along approximately 50% of the axial length of the first magnetic gap, the entire axial length of the region with greater magnetoresistance, and approximately 50% of the axial length of the second magnetic gap, while the second coil portion is positioned completely outside the second magnetic gap. [Figure 2C] Figure 1A shows the transducer assembly driven in a second direction from the configuration shown in Figure 2B. The first coil portion is positioned along substantially the entire axial length of the region with greater magnetoresistance and substantially the entire axial length of the second magnetic gap, while the second coil portion is positioned completely outside the second magnetic gap. [Figure 2D] Figure 1A shows the transducer assembly driven in a second direction from the configuration shown in Figure 2C. The first coil portion is positioned along approximately 70% of the axial length of the second magnetic gap, and the second coil portion is positioned completely outside the second magnetic gap. [Figure 3] Figure 1A shows the transducer assembly with its components and a second magnet. Here, the first plate and the second plate are positioned between the first magnet and the second magnet. [Figure 4A]Figure 3 shows the transducer assembly components, but the second magnet is positioned between the first and second plates, and the cross-sectional view of the transducer assembly is shown in half. [Figure 4B] Figure 4B shows half of a cross-sectional view of the transducer assembly, which includes the components of the transducer assembly and a third magnet. Here, the first plate is positioned between the third magnet and the second magnet, and the second plate is positioned between the first magnet and the second magnet. [Figure 5] Figure 1A shows the transducer assembly components, but the first magnet is positioned radially outward from the first and second plates. This is a half-section of the transducer assembly. [Figure 6] Figure 1A shows the transducer assembly components, but the first plate is coupled to the first magnet at a first position which is radially outward from the second position where the second plate is coupled to the first magnet, and half of the cross-sectional view of the transducer assembly is shown. [Figure 7] Figure 1A shows half of a cross-sectional view of a transducer assembly having components of the transducer assembly and pole piece components coupled to a pole piece. Here, the pole piece components include recesses aligned axially with regions of greater magnetic resistance. [Figure 8] Figure 1A shows all the components of the transducer assembly and half of a cross-sectional view of the transducer assembly having a cap magnet coupled to a pole piece. [Figure 9] Figure 1A shows the transducer assembly components, but with a half-section of a transducer assembly having an intermediate coil section with reduced winding density between the first coil section and the second coil section. [Figure 10] Figure 1A shows the components of the transducer assembly, but also shows half of a cross-sectional view of a transducer assembly having an auxiliary coil axially positioned on a former between the first coil portion and the second coil portion. [Figure 11]Figure 1A shows the transducer assembly components, but in the region of greater magnetoresistance, the first and second plates have tapered recesses, and half of the cross-sectional view of the transducer assembly is shown. [Figure 12] Figure 1A shows the components of the transducer assembly, but this figure shows half of a cross-sectional view of the transducer assembly with a third plate. [Modes for carrying out the invention]

[0029] Figures 1A to 1E show a transducer assembly 100, which may also be referred to as a loudspeaker motor, motor assembly, and / or voice coil motor. The transducer assembly 100 can be incorporated into speaker devices in a variety of applications, which may include at least a vehicle (e.g., the interior trim of a vehicle) or a structure.

[0030] The transducer assembly 100 may include a yoke 102, which may also be called a ferromagnetic yoke. The yoke 102 may include a pole piece 104 (e.g., a central ferromagnetic component) and / or a peripheral portion 106. The peripheral portion 106 may be positioned radially outward of the pole piece 104 with respect to the axis 170 of the transducer assembly 100, and / or may include an annular shape. The pole piece 104 may be an elongated member. The pole piece 104 may include cross-sections having outer perimeters of various shapes, including at least circular, oval, elliptical, polygonal (e.g., square, rectangle, etc.), and / or irregular shapes. The yoke 102 and its components may be made of various materials, including at least a ferromagnetic material (e.g., steel, iron, etc.).

[0031] The transducer assembly 100 may include a former 108, which may also be referred to as a coil former, tubular member, bobbin, and / or coil bobbin. The former 108 may be positioned on or around the pole piece 104. The former 108 may have a shape corresponding to the shape of the pole piece 104. The former 108 may be rigid. The former 108 may have a closed shape and may be positioned around the pole piece 104.

[0032] The transducer assembly 100 may include a first coil portion 110 and / or a second coil portion 112, which may be referred to as a coil, a conductive coil portion, a voice coil, a coil body, and / or a winding body. The first coil portion 110 and / or the second coil portion 112 may be placed on a former 108. The first coil portion 110 and the second coil portion 112 are windable in the same direction. The first coil portion 110 and the second coil portion 112 can be electrically connected in series. The first coil portion 110 and the second coil portion 112 can carry current in the same direction. The first coil portion 110 and the second coil portion 112 can rotate about an axis 170. The first coil portion 110 and the second coil portion 112 are windable in circular, oval, elliptical, polygonal (e.g., square, rectangle, etc.) and / or irregular shapes. The first coil portion 110 and the second coil portion 112 can be spaced apart from each other axially on the former 108. In some modifications, the first coil portion 110 and the second coil portion 112 may not be connected via windings. In some modifications, the first coil portion 110 and the second coil portion 112 can be part of the same coil, which may include being connected via an intermediate coil portion with reduced winding density. The first coil portion 110 and the second coil portion 112 can be wound in the same direction around the mandrel.

[0033] The transducer assembly 100 may include a first magnet 114, which may be a permanent magnet. The first magnet 114 may have an annular, rod-shaped, or disc-shaped form. The first magnet 114 may be positioned around the pole piece 104. The first magnet 114 may be coupled (e.g., glued) to the yoke 102, which may include being coupled to the peripheral portion 106. The first magnet 114 may have a magnetization direction distal to the direction of arrow 130.

[0034] The transducer assembly 100 may include a first plate 116 and / or a second plate 118 (e.g., a ferromagnetic element). The first plate 116 and / or the second plate 118 may include an annular structure. The first plate 116 and / or the second plate 118 may be made of a variety of materials, which may include at least a ferromagnetic material (e.g., steel, iron, etc.). The second plate 118 may be positioned axially between the first plate 116 and the first magnet 114. The second plate 118 may be coupled (e.g., bonded) to the first magnet 114. The first plate 116 and the second plate 118 may protrude more radially inward toward the pole piece 104 compared to the first magnet 114. A first magnetic gap 120, which may also be called an air gap, may be positioned radially between the first plate 116 and the pole piece 104. The first magnetic gap 120 can be positioned radially between the pole piece 104 and the portion of the first plate 116 closest to the pole piece 104. The closest portion of the first plate 116 can be the portion that is the shortest radial distance from the outer surface of the pole piece 104. The second magnetic gap 122, which may also be called an air gap, can be positioned radially between the second plate 118 and the pole piece 104. The second magnetic gap 122 can be positioned radially between the pole piece 104 and the portion of the second plate 118 closest to the pole piece 104. The closest portion of the second plate 118 can be the portion that is the shortest radial distance from the outer surface of the pole piece 104. The first magnetic gap 120 and the second magnetic gap 122 can be spaced apart from each other in the axial direction. The first magnetic gap 120 and the second magnetic gap 122 can contain magnetic flux in the same direction. The axial lengths of the first magnetic gap 120 and the second magnetic gap 122 can be the same.

[0035] The transducer assembly 100 may include a region 124 having greater magnetoresistance compared to the first magnetic gap 120 and the second magnetic gap 122. The region 124 may be axially positioned between the first magnetic gap 120 and the second magnetic gap 122. The first plate 116 and the second plate 118 can cooperate to form the region 124. The first plate 116 may include a first recess 126 radially with respect to the axis 170 to form the region 124. The second plate 118 may include a second recess 128 radially with respect to the axis 170 to form the region 124. The first recess 126 and the second recess 128 can cooperate to form the region 124. In some variations, only one of the first recess 126 and the second recess 128 forms the region 124. The distance between the first plate 116 and the pole piece 104 can be smaller in the first magnetic gap 120 than the distance between the first recess 126. The distance between the second plate 118 and the pole piece 104 can be smaller in the second magnetic gap 122 than the distance between the second recess 128. The first recess 126 and the second recess 128 can be located at various positions on the first plate 116 and the second plate 118, respectively. The first recess 126 and / or the second recess 128 can have various shapes (e.g., polygonal cross-sections) and / or sizes. The first recess 126 can be located at a corner of the first plate 116 (e.g., an inner and proximal corner), which may involve the formation of a step (e.g., a step having two faces positioned substantially perpendicular to each other). The second recess 128 can be located at a corner of the second plate 118 (e.g., an inner and distal corner), which may involve the formation of a step (e.g., a step having two surfaces positioned substantially perpendicular to each other). The first recess 126 and the second recess 128 can be mirror images of each other. The first recess 126 and the second recess 128 can be adjacent to each other when the first plate 116 and the second plate 118 are joined together.With the first plate 116 coupled to the second plate 118, the first recess 126 and the second recess 128 can cooperate to form a substantially continuous recess in the coupled first plate 116 and second plate 118, thereby forming a region 124. The substantially continuous recess is roughly U-shaped and can open radially inward toward the axis 170. The first magnet 114, the first plate 116, and / or the second plate 118 can be collectively referred to as a magnetic structure.

[0036] The components and features of the transducer assembly 100 can be sized, shaped, and / or arranged such that the transducer assembly maintains a substantially consistent BL product as it is driven over a stroke in first and second directions (e.g., distal and proximal directions). For example, the combined axial length of the first coil portion 110 and the second magnetic gap 122, which are positioned (e.g., immersed) within the first magnetic gap 120 and the second magnetic gap 122, can be substantially the same over the entire stroke of the transducer assembly 100. The axial lengths of the first magnetic gap 120 and the second magnetic gap 122 can be substantially the same. The axial lengths of the first coil portion 110 and the second coil portion 112 can be substantially the same. The axial lengths of the first coil portion 110 and the second coil portion 112 can be substantially the same as the combined axial length of region 124 and the first magnetic gap 120. The axial lengths of the first coil portion 110 and the second coil portion 112 can be substantially the same as the combined axial length of the region 124 and the second magnetic gap 122. The first coil portion 110 and the second coil portion 112 can be spaced apart from each other in the axial direction by a length substantially the same as the length of the first coil portion 110. The first coil portion 110 and the second coil portion 112 can be spaced apart from each other in the axial direction by a length substantially the same as the length of the second coil portion 112. In some modifications, the first coil portion 110 and the second coil portion 112 can be spaced apart from each other in the axial direction by a length greater than or less than the lengths of the first coil portion 110 and the second coil portion 112. As shown in Figure 1A, with the transducer assembly 100 in a stationary configuration, the first coil portion 110 can be positioned (e.g., occupied) over approximately half the axial length of the first magnetic gap 120, and the second coil portion 112 can be positioned (e.g., occupied) over approximately half the axial length of the second magnetic gap 122. In some modifications, this arrangement can leave a region 124 that is not occupied by the first coil portion 110 or the second coil portion 112.Accordingly, when the transducer assembly 100 is stationary, the first coil portion 110 may be immersed over approximately half the axial length of the magnetic flux field of the first magnetic gap 120, and the second coil portion 112 may be immersed over approximately half the axial length of the magnetic flux field of the second magnetic gap 122.

[0037] The first coil portion 110 and the second coil portion 112, positioned on the former 108, can move together in the same direction as the transducer assembly 100 is driven. The first coil portion 110 and the second coil portion 112, positioned on the former 108, can move oscillatingly relative to the stationary configuration shown in Figure 1A. This may include axial movement by substantially the same displacement in both directions (e.g., distal and proximal directions). The first coil portion 110 and the second coil portion 112, positioned on the former 108, can receive a driving force proportional to the current flowing through the first coil portion 110 and the second coil portion 112, which originates from a voltage source, such as a music signal or any other AC input from a power amplifier, for example.

[0038] As described herein, the portion of the combined axial length of the first magnetic gap 120 and the second magnetic gap 122 occupied by the first coil portion 110 and / or the second coil portion 112 can be substantially consistent when the transducer assembly 100 is driven in the distal and proximal directions, thereby providing a substantially consistent speaker force coefficient. For example, while the transducer assembly 100 is driven, the first coil portion 110 and / or the second coil portion 112 can occupy about half of the combined axial length of the first magnetic gap 120 and the second magnetic gap 122. While the transducer assembly 100 is driven, the combined lengths of the first coil portion 110 and the second coil portion 112 immersed in the first magnetic gap 120 and the second magnetic gap 122 can be substantially the same. The force coefficient of the speaker of the stationary transducer assembly 100 can be approximately 50% of the force coefficient of the speaker of an overhang motor having a gap height equal to the sum of the upper and lower gap heights.

[0039] As the first coil portion 110 and the second coil portion 112, positioned on the former 108, are driven distally in the direction of arrow 130, more of the second coil portion 112 moves into the second magnetic gap 122, allowing the first coil portion 110 to move out of the first magnetic gap 120, thereby maintaining a substantially consistent speaker force coefficient. With the entire first coil portion 110 positioned outside the first magnetic gap 120, as the first coil portion 110 and the second coil portion 112, positioned on the former 108, are driven distally in the direction of arrow 130, the second coil portion 112 can occupy the entire axial length of the second magnetic gap 122, then a portion of the axial length of the first magnetic gap 120 and the second magnetic gap 122, then substantially the entire axial length of the first magnetic gap 120, thereby maintaining a substantially consistent speaker force coefficient.

[0040] As the first coil portion 110 and the second coil portion 112, positioned on the former 108, are driven proximally in the direction opposite to arrow 130, more of the first coil portion 110 moves into the first magnetic gap 120, while the second coil portion 112 can move out of the second magnetic gap 122, thereby maintaining a substantially consistent speaker force coefficient. With the entire second coil portion 112 positioned outside the second magnetic gap 122, as the first coil portion 110 and the second coil portion 112, positioned on the former 108, are driven proximally in the direction opposite to arrow 130, the first coil portion 110 can occupy the entire axial length of the first magnetic gap 120, then a portion of the axial length of the first magnetic gap 120 and the second magnetic gap 122, then substantially the entire axial length of the second magnetic gap 122, thereby maintaining a substantially consistent speaker force coefficient.

[0041] The transducer assembly 100 can be incorporated into a loudspeaker assembly which may include at least a diaphragm, spider, surround, enclosure, frame, baffle, dust cap, and / or other features. The transducer assembly 100 may include additional reinforcing features which may include at least conductive metal elements (e.g., rings and / or fixed coils) for facilitating airflow and / or reducing electromagnetic short circuits and / or electrical inductance of the coil, either when stationary or in operation. The metal elements may be positioned at least above, inside, or below the gap.

[0042] Figure 1B shows the first coil portion 110 and the second coil portion 112, positioned on the former 108, moving distally in the direction of arrow 130, with a current of the first polarity flowing through them. As shown, the first coil portion 110 can move substantially out of the first magnetic gap 120, and the second coil portion 112 can move to occupy substantially the entire axial length of the second magnetic gap 122, thereby providing a speaker force coefficient that is substantially the same (e.g., 100%) as that of the stationary transducer assembly 100 in the configuration shown in Figure 1A. The proportion of the first coil portion 110 deviating from the axial length of the first magnetic gap 120 can be substantially the same as the proportion of the second coil portion 112 moving to occupy the axial length of the second magnetic gap 122.

[0043] Figure 1C shows the first coil portion 110 and the second coil portion 112, positioned on the former 108, moving further distally in the direction of arrow 130 relative to the configuration shown in Figure 1B. As illustrated, the first coil portion 110 can continue to move distally outside the first magnetic gap 120, and the second coil portion 112 can move to occupy approximately half the axial length of the first magnetic gap 120, the entire axial length of region 124, and approximately half the axial length of the second magnetic gap 122, thereby providing a speaker force coefficient that is substantially the same (e.g., 100%) as the stationary transducer assembly 100 in the configuration shown in Figure 1A. The proportion by which the second coil portion 112 deviates from the axial length of the second magnetic gap 122 can be substantially the same as the proportion by which the second coil portion 112 moves to occupy the axial length of the first magnetic gap 120. The first coil portion 110 and the second coil portion 112 can be connected in series so that the induced back electromotive force of the second coil portion 112 reduces the current flow in the first coil portion 110, which is outside the first magnetic gap 120 (for example, in free air), thereby reducing current-related heat generation in the coil windings and preventing overheating.

[0044] Figure 1D shows how the first coil portion 110 and the second coil portion 112, positioned on the former 108, move further distally in the direction of arrow 130 relative to the configuration shown in Figure 1C. As shown, the first coil portion 110 can continue to move distally outside the first magnetic gap 120, and the second coil portion 112 can move so as to be positioned along substantially the entire axial length of the first magnetic gap 120 and substantially the entire axial length of the region 124, thereby providing a speaker force coefficient that is substantially identical (e.g., 100%) to that of the stationary transducer assembly 100 in the configuration shown in Figure 1A.

[0045] In some modifications, as shown in Figure 1E, the first coil portion 110 and the second coil portion 112 positioned on the former 108 can continue to move further distally in the direction of arrow 130 compared to the configuration shown in Figure 1D. As illustrated, the first coil portion 110 can continue to move distally outside the first magnetic gap 120, and the second coil portion 112 can move to be positioned partially distal to the first magnetic gap 120 and along about 70% of the axial length of the first magnetic gap 120, thereby providing about 70% of the force coefficient of the speaker of the stationary transducer assembly 100 in the configuration shown in Figure 1A. 70% of the force coefficient of the stationary speaker of the transducer assembly 100 may also be BL-limited Xmax, which may correspond to about 35% of the force coefficient of the speaker of an overhang motor having a gap height equal to the sum of the upper and lower gap heights. In some variations, the first coil portion 110 and the second coil portion 112 positioned on the former 108 can continue to move further distally so as to be positioned along approximately 90%, 80%, 70%, 60%, or less than 50% of the axial length of the first magnetic gap 120, or any percentage in between the aforementioned.

[0046] Figure 2A shows the first coil portion 110 and the second coil portion 112, positioned on the former 108, moving proximally in the direction of arrow 132, with a current of a second polarity (e.g., reversed from the first polarity) flowing through them. The first coil portion 110 and the second coil portion 112, positioned on the former 108, can move backward proximally through the configurations shown in Figures 1D, 1C, 1B, and 1A until they reach the configuration shown in Figure 2A. As shown in Figure 2A, the first coil portion 110 can be moved to be positioned along substantially the entire axial length of the first magnetic gap 120, and the second coil portion 112 can be moved to be positioned substantially outside the second magnetic gap 122, thereby providing a speaker force coefficient that is substantially the same (e.g., 100%) as the stationary transducer assembly 100 in the configuration shown in Figure 1A.

[0047] Figure 2B shows how the first coil portion 110 and the second coil portion 112, positioned on the former 108, move further proximal in the direction of arrow 132 relative to the configuration shown in Figure 2A. As shown, the first coil portion 110 can move so as to be positioned along approximately half the axial length of the first magnetic gap 120, the entire axial length of region 124, and approximately half the axial length of the second magnetic gap 122, and the second coil portion 112 can continue to move proximal outside the second magnetic gap 122, thereby providing a speaker force coefficient that is substantially the same (e.g., 100%) as the stationary transducer assembly 100 in the configuration shown in Figure 1A. The proportion of the first coil portion 110 that is out of the axial length of the first magnetic gap 120 can be substantially the same as the proportion of the first coil portion 110 that occupies the axial length of the second magnetic gap 122. The first coil portion 110 and the second coil portion 112 can be connected in series so that the induced back electromotive force of the first coil portion 110 reduces the current flow in the second coil portion 112, which is outside the second magnetic gap 122 (for example, in free air), thereby reducing current-related heat generation in the coil windings and preventing overheating.

[0048] Figure 2C shows how the first coil portion 110 and the second coil portion 112, positioned on the former 108, move further proximal in the direction of arrow 132 relative to the configuration shown in Figure 2B. As shown, the second coil portion 112 can continue to move proximal outside the second magnetic gap 122, and the first coil portion 110 can move so as to be positioned along substantially the entire axial length of the second magnetic gap 122 and along the axial length of region 124, thereby providing a speaker force coefficient that is substantially identical (e.g., 100%) to that of the stationary transducer assembly 100 in the configuration shown in Figure 1A.

[0049] In some modifications, as shown in Figure 2D, the first coil portion 110 and the second coil portion 112 positioned on the former 108 can continue to move further proximal in the direction of arrow 132 compared to the configuration shown in Figure 2C. As illustrated, the second coil portion 112 can continue to move proximal outside the second magnetic gap 122, and the first coil portion 110 can move to be positioned partially proximal to the second magnetic gap 122 and along about 70 percent of the axial length of the second magnetic gap 122, thereby providing about 70% of the force coefficient of the speaker of the stationary transducer assembly 100 in the configuration shown in Figure 1A. 70% of the force coefficient of the stationary speaker of the transducer assembly 100 may also be BL-limited Xmax, which may correspond to 35% of the force coefficient of the speaker of an overhang motor having a gap height equal to the sum of the upper and lower gap heights. In some variations, the first coil portion 110 and the second coil portion 112 positioned on the former 108 can continue to move further proximal so that the second coil portion 112 is positioned along approximately 90%, 80%, 70%, 60%, or less than or equal to 50% of the axial length of the second magnetic gap 122, or any percentage in between the aforementioned.

[0050] Figure 3 shows a transducer assembly 101 that may include features of at least one of the transducer assembly 100 and other transducer assemblies disclosed herein. The transducer assembly 101 may include a second magnet 160 that may include features of at least one of the first magnet 114. The second magnet 160 may be positioned (e.g., bonded) on the distal-facing surface of the first plate 116. The first plate 116 and the second plate 118 may be positioned between the first magnet 114 and the second magnet 160. The second magnet 160 may have a magnetization direction opposite to that of the first magnet 114. For example, the first magnet 114 may have a magnetization direction distal in the direction of arrow 136, and the second magnet 160 may have a magnetization direction proximal in the direction of arrow 134. This arrangement may be desirable to supply additional magnetic flux to generate magnetic flux in the same direction within each gap, as indicated by arrows 138 and 140, and / or to improve (e.g., optimize) the flow and / or distribution of magnetic flux within the magnetic assembly and / or between the first magnetic gap 120 and the second magnetic gap 122. The direction of the magnetic flux in the first plate 116 and the second plate 118 can be radially inward.

[0051] Figure 4A shows a transducer assembly 200 that may include features of at least one of the transducer assembly 101 and other transducer assemblies disclosed herein. The transducer assembly 200 may include a second magnet 160. The second magnet 160 may be positioned between the first plate 116 and the second plate 118, which may include at least adhering to the proximal-facing surface of the first plate 116 and / or the distal-facing surface of the second plate 118. The second magnet 160 may cause the first plate 116 and the second plate 118 to be axially separated from each other, thereby lengthening the region 124 in the axial direction. The second magnet 160 may have the same magnetization direction as the first magnet 114. For example, the first magnet 114 may have a magnetization direction distal in the direction of arrow 136, and the second magnet 160 may have a magnetization direction distal in the direction of arrow 142. This arrangement may be desirable to supply additional magnetic flux and / or to improve (e.g., optimize) the flow and / or distribution of magnetic flux within the magnetic assembly and / or between the first magnetic gap 120 and the second magnetic gap 122.

[0052] Figure 4B shows a transducer assembly 201 which may include features of at least one of the transducer assembly 200 and other transducer assemblies disclosed herein. The transducer assembly 201 may include a third magnet 162 which may include features of at least one of the first magnet 114 and / or the second magnet 160. The third magnet 162 may be positioned (e.g., bonded) on the first plate 116, which may include the distally oriented surface of the first plate 116. The first plate 116 may be positioned between the second magnet 160 and the third magnet 162. The second plate 118 may be positioned between the first magnet 114 and the second magnet 160. The third magnet 162 may have a magnetization direction opposite to that of the second magnet 160 and / or the first magnet 114. For example, the third magnet 162 may have a magnetization direction proximal to the direction of arrow 144, and the first magnet 114 and / or the second magnet 160 may have magnetization directions distal to the directions of arrows 136 and 142, respectively. This arrangement may be desirable to supply additional magnetic flux and / or to improve (e.g., optimize) the flow and / or distribution of magnetic flux within the magnetic assembly and / or between the first magnetic gap 120 and the second magnetic gap 122.

[0053] Figure 5 shows a transducer assembly 300 that may include features of transducer assembly 100 and at least one of other transducer assemblies disclosed herein. The first magnet 114 can be oriented to have a radially inward magnetization direction which is radially inward with respect to the pole piece 104 and / or axis 170. The first magnet 114 can be oriented to have a radially inward magnetization direction which is perpendicular to the direction of magnetic flux in the first magnetic gap 120 and / or second magnetic gap 122. The first magnet 114 can be placed (e.g., bonded) on the peripheral portion 106, which may include the radially inward surface of the peripheral portion 106. The first plate 116 and / or second plate 118 can be placed between the first magnet 114 and the pole piece 104. The first plate 116 and / or second plate 118 can be placed on the first magnet 114, which may include the radially inward surface of the peripheral portion 106. The first magnet 114 can be positioned radially between the first plate 116 and the peripheral portion 106. The first magnet 114 can also be positioned radially between the second plate 118 and the peripheral portion 106. The magnetic fluxes of the first plate 116 and the second plate 118 can be in the same direction, as indicated by arrows 146 and 148.

[0054] Figure 6 shows a transducer assembly 400 that may include features of at least one of the transducer assembly 100 and other transducer assemblies disclosed herein. A first plate 116 can be positioned (e.g., bonded) to a first magnet 114. A second plate 118 can be positioned (e.g., bonded) to the first magnet 114. The first plate 116 and the second plate 118 can be positioned concentrically with respect to each other. The second plate 118 can be positioned radially inward of the first plate 116. The second plate 118 can be bonded to the first magnet 114 at a position radially inward with respect to the position where the first plate 116 is bonded to the first magnet 114. The second plate 118 can be positioned within a first recess 126 of the first plate 116. The first plate 116 may have an inverted L-shape, with the end of its stem positioned (e.g., glued) on the first magnet 114 and its legs projecting radially inward toward the pole piece 104 and / or axis 170 to form the first magnetic gap 120. The second plate 118 may have an L-shape, with the elongated side of its stem positioned (e.g., glued) on the first magnet 114 and its legs projecting distally in a direction substantially parallel to the axis 170 and / or pole piece 104 to form the second magnetic gap 122. The cross-section (e.g., radial cross-section) of the second plate 118 may be thinner than the cross-section (e.g., radial cross-section) of the first plate 116. In some modifications, this arrangement can equilibrium the movement of magnetic flux between the first magnetic gap 120 and the second magnetic gap 122 by using the magnetic saturation state of one or both of the first plate 116 and the second plate 118.

[0055] Figure 7 shows a transducer assembly 500 that may include features of transducer assembly 100 and at least one of other transducer assemblies disclosed herein. The pole piece 104 may include a recess 152 (e.g., a notch, a channel). The recess 152 may be axially aligned with region 124 such that region 124 is radially outward of the recess 152. Region 124 and the recess 152 may together increase the magnetoresistance between the first magnetic gap 120 and the second magnetic gap 122, which may include providing greater magnetoresistance than can be achieved by the first coil portion 110, the second coil portion 112, and one radial side of the former 108 alone. The pole piece 104 may include a pole piece component 154 (e.g., the distal end of the pole piece 104) that can be coupled to the pole piece 104. The pole piece component 154 may include a recess 152. The pole piece component 154 may be located on the distal end of the pole piece 104. The pole piece 104, the yoke 102, the first plate 116, the second plate 118, and / or any ferromagnetic (e.g., steel) component of the magnetic structure can be divided into two or more components, which may be helpful in manufacturing and / or assembly. In some modifications, multiple components can be used for features without substantially altering the movement of the magnetic flux of the transducer assembly 500. Components of the magnetic structure may be shared with frame members of the speaker frame made of ferromagnetic material.

[0056] Figure 8 shows a transducer assembly 501 which may include features of at least one of the transducer assembly 100 and other transducer assemblies disclosed herein. The transducer assembly 501 may include a cap magnet 150. The cap magnet 150 may be positioned (e.g., bonded) on the pole piece 104 of the yoke 102, which may include the distal end of the pole piece 104. The cap magnet 150 can provide focusing and / or enhancement of magnetic saturation of the ferromagnetic components of the transducer assembly 501, and / or additional return paths for the magnetic circuit. In some modifications, the cap magnet 150 may have an outer circumference that does not extend radially outward from the outer circumference of the pole piece 104. The cap magnet 150 may include features of the first magnet 114 or any of the other magnets described herein.

[0057] Figure 9 shows a transducer assembly 600 that may include features of at least one of the transducer assembly 100 and other transducer assemblies disclosed herein. In some modifications, the first coil portion 110 and the second coil portion 112 may be formed by a continuous coil winding (e.g., coiled wire) arranged around the former 108. In some modifications, the first coil portion 110 and the second coil portion 112 may be formed by one or more continuous layers of coil windings arranged around the former 108. The coil windings may be arranged (e.g., wound) around the former 108 and distributed axially on the former to form the first coil portion 110, the second coil portion 112, and an intermediate coil portion 156 between the first coil portion 110 and the second coil portion 112. The intermediate coil portion 156 may include a reduced winding density compared to the first coil portion 110 and the second coil portion 112. The intermediate coil section 156 can connect the first coil section 110 and the second coil section 112 to facilitate a continuous coil winding, thereby enabling the first coil section 110 and the second coil section 112 to be wound as a single winding. The intermediate coil section 156 can span between the first coil section 110 and the second coil section 112. Compared to the intermediate coil section 156, which may contain a coil winding with reduced winding density, the first coil section 110 and the second coil section 112 may contain a coil winding with increased density (e.g., additional layers). The first coil section 110 can be located on the distal portion of the former 108. The second coil section 112 can be located on the proximal portion of the former 108. This arrangement can provide a more continuous driving force and / or avoid discontinuities in the driving force.

[0058] Figure 10 shows a transducer assembly 601 which may include features of at least one of the transducer assembly 100 and other transducer assemblies disclosed herein. The transducer assembly 601 may include an auxiliary coil portion 158 (e.g., an auxiliary coil winding, a conductive element forming an auxiliary electrical loop), which may include an additional wire coil or a closed ring of conductive material forming a continuous or electrically short-circuited auxiliary loop. The auxiliary coil portion 158 may be positioned (e.g., bonded) on the former 108. The auxiliary coil portion 158 may be positioned around the former 108. The auxiliary coil portion 158 may include a wire coil or a closed ring separate from the first coil portion 110 and / or the second coil portion 112. The auxiliary coil portion 158 may be positioned axially between the first coil portion 110 and the second coil portion 112. The auxiliary coil portion 158 may provide electromechanical damping and / or braking of the motion of the transducer assembly 601. In some modifications, the attached coil portion 158 can be used for position sensing, velocity sensing, temperature sensing, and / or proximity sensing, and the attached coil may work in cooperation with another stationary attached coil located in an adjacent area of ​​the motor assembly to perform these sensing or braking functions.

[0059] Figure 11 shows a transducer assembly 700 that may include features of at least one of the transducer assembly 100 and other transducer assemblies disclosed herein. The first recess 126 of the first plate 116 may be tapered, thereby allowing the radial width of the region 124 to gradually decrease distally. The second recess 128 of the second plate 118 may be tapered, thereby allowing the radial width of the region 124 to gradually decrease proximal to 124. The arrangement of the second recess 128 may be a mirror image of the arrangement of the first recess 126. The taper ratio of the first recess 126 may be the same as that of the second recess 128. The characteristics (e.g., size and / or shape) of the first recess 126 and the second recess 128 may be modified as shown in Figure 11 to provide a specific characteristic distribution of magnetic flux within the region 124 between the first magnetic gap 120 and the second magnetic gap 122.

[0060] Figure 12 shows a transducer assembly 800 that may include features of at least one of the transducer assembly 100 and other transducer assemblies disclosed herein. The transducer assembly 800 may include a third plate 164 that may include features of at least one of the first plate 116 and / or the second plate 118. The third plate 164 may be positioned (e.g., bonded) on the first plate 116, which may include being positioned on the distally oriented surface of the first plate 116. The first plate 116 may be positioned axially between the third plate 164 and the second plate 118. The third plate 164 may form a third magnetic gap 172 radially between the pole piece 104 and the third plate 164. The third plate 164 may include a third recess 168 that may include features of either the first recess 126 and / or the second recess 128. The third recess 168 can form a region 166 with greater magnetoresistance in the axial direction between the first magnetic gap 120 and the third magnetic gap 172. The third recess 168 can radially separate the third plate 164 from the pole piece 104. The third recess 168 may have a size and / or shape that matches the combined size and / or shape of the first recess 126 and the second recess 128. The axial length of the third recess 168 may be the same as the combined axial length of the first recess 126 and the second recess 128. The axial length of the third magnetic gap 172 may be the same as the first magnetic gap 120 and / or the second magnetic gap 122. The size and / or shape of the third magnetic gap 172 may be the same as the size and / or shape of the first magnetic gap 120 and / or the second magnetic gap 122.The first coil portion 110 and the second coil portion 112 can be spaced apart axially, which may include lengthening the former 108 such that, when the transducer assembly 800 is stationary, the first coil portion 110 is positioned along approximately half the axial length of the third magnetic gap 172, and the second coil portion 112 is positioned along approximately half the axial length of the second magnetic gap 122. In some modifications, the addition of a third plate 164 can facilitate greater travel lengths of the first coil portion 110 and the second coil portion 112 through a state of substantially constant speaker force coefficient for a highly linear magnetic force (e.g., magnetic flux immersion). In some modifications, the transducer assembly 800 may include more than three plates, more than three magnetic gaps, more than two regions with greater magnetoresistance, and / or more than two coil portions.

[0061] The voice coil windings (e.g., the voice coil sections) can be connected in series. In some modifications, a dual voice coil arrangement can be implemented. In some modifications, both voice coil sections (e.g., the voice coil windings) may be provided with separate AC drive units.

[0062] A former (e.g., a tubular member) on which a voice coil portion is mounted can be moved distally and proximally along the pole piece described herein by electric current. For example, the voice coil portion can be mounted within a magnetic gap (e.g., within the magnetic field of a magnet). An electrical signal, such as an audio signal, flows through the voice coil portion, and the interaction between the electrical signal (e.g., electric current) and the magnetic field can provide a fluctuating magnetic field around the voice coil portion. The interaction between the magnetic field of the voice coil portion and the magnetic field of a permanent magnet can move the voice coil portion and the former on which the voice coil portion is mounted. The direction of the current can change the direction of movement (e.g., distal and proximal movement). A diaphragm, such as a cone, can be attached to the former and / or at least one voice coil portion (e.g., the distal voice coil portion). As the former and voice coil portion move, the diaphragm may also move, generating pressure waves in the air, which can be perceived as sound by the ear and / or a microphone. The frequency and / or amplitude of the electrical signal can determine the pitch and / or volume of the sound produced.

[0063] The stroke (e.g., displacement) of a transducer assembly can refer to the distal and proximal movement of the voice coil portion and former, which may include complete distal and proximal movement. For example, one stroke of a transducer assembly can refer to the movement of the former and voice coil portion from the stationary position to the most distal position, to the most proximal position, and back to the stationary position. As described herein, the force coefficient of the speaker of a transducer assembly can be substantially consistent throughout the stroke. For example, the force coefficient of the speaker can remain less than 10%, less than 5%, less than 1%, less than 0.1%, and less than 0.01% of the force coefficient of the speaker of a transducer assembly in the stationary state throughout the stroke. In some modifications, the force coefficient of the speaker of a transducer assembly can be substantially consistent over most of the stroke. For example, the speaker force coefficient may remain below 10%, 5%, 1%, 0.1%, and 0.01% of the speaker force coefficient of the stationary transducer assembly over most of the stroke. Most of the stroke may include more than 50% of the movement of the former and voice coil portions during the stroke. As described with reference to Figures 1A to 2D, in some modifications, the speaker force coefficient of the transducer assembly may decrease to less than the speaker force coefficient when the transducer assembly is stationary if the most proximal voice coil portion moves distally outside the most distal magnetic gap, or if the most distal voice coil portion moves proximal outside the most proximal magnetic gap, and this can occur at the distal and proximal moving ends of the former and voice coil portions. The need to control the force coefficient over the stroke range is to control the total harmonic distortion and intermodulation distortion (e.g., THD, IMD) of the operating transducer within acceptable thresholds.

[0064] The scope of the disclosure disclosed herein is not intended to be limited by the specific embodiments disclosed above. For example, while a transducer assembly is sometimes described in the context of vehicle interior trim, the transducer assemblies described herein can also be used in other contextual relationships. Various modifications and alternative forms are possible of the disclosure, specific examples of which are shown in the drawings and described in detail herein. The disclosure is not limited to the detailed forms or methods disclosed, but rather encompasses all equivalents, modifications, and alternatives that fall within the various embodiments described and the accompanying claims and spirit. Various features of the transducer assemblies described herein can be combined to form further embodiments that are part of the disclosure.

[0065] Methods of using transducer assemblies and / or loudspeakers (including devices, apparatus, assemblies, structures, etc.) are included herein, and such methods of use may include using or assembling one or more features disclosed herein to achieve one or more functions and / or features of the system discussed herein. Methods of manufacturing the aforementioned system are included, and such manufacturing methods may include providing, fabricating, connecting, assembling, and / or installing one or more features of the system disclosed herein to achieve the functions and / or features of the system discussed herein.

[0066] In light of the above teachings, various other modifications, adaptations, and alternative designs are naturally possible. Therefore, it should be understood at this point that, within the scope of the appended claims, the disclosure may be implemented in ways other than those specifically described herein. Various combinations or partial combinations of specific features and modifications of the embodiments disclosed above may be made, but are still considered to fall within the scope of one or more disclosures. Furthermore, any specific features, aspects, methods, characteristics, properties, qualities, attributes, elements, etc., disclosed herein relating to an embodiment can be used in all other embodiments described herein. Therefore, it should be understood that various features and modifications of the disclosed embodiments can be combined with or substituted for each other to form various forms of the disclosure. Accordingly, the scope of the disclosure disclosed herein is not intended to be limited by the specific disclosed embodiments described above. Furthermore, the disclosure allows for various modifications and alternative forms, specific examples of which are shown in the drawings and described in detail herein. However, this disclosure is not limited to any particular form or method disclosed. On the contrary, it should be understood that this disclosure encompasses all modifications, equivalents, and substitutes that fall within the spirit and scope of the various embodiments described and the accompanying claims. None of the methods disclosed herein need to be performed in the order listed. The scope disclosed herein also encompasses all overlaps, sub-scopes, and combinations thereof. The terms “up to,” “at least,” “greater than,” “less than,” and “between” include the numbers listed. Quantitative descriptors used herein that precede terms such as “approximately,” “about,” and “substantially” (e.g., length, width, quantity, distance, proportion, percentage, fraction, relationship, etc.) include the described descriptor and also represent quantities close to the described quantitative descriptor that perform the desired function or achieve the desired result.For example, the terms “approximately,” “about,” and “substantially” can refer to quantities that are within the range of less than 10%, less than 5%, less than 1%, less than 0.1%, and less than 0.01% of the stated quantity. For example, the description mentions that the coil portion occupies about half of the axial gap length, which can refer to quantities that are within the range of less than 10%, less than 5%, less than 1%, less than 0.1%, and less than 0.01% of half. In another example, the aforementioned description mentions that the two lengths are approximately equal, which can refer to quantities that are within the range of less than 10%, less than 5%, less than 1%, less than 0.1%, and less than 0.01% of the equal length. [Explanation of symbols]

[0067] 100…Transducer assembly, 101…Transducer assembly, 102…Yoke, 104…Pole piece, 106…Peripheral part, 108…Former, 110…First coil part, 112…Second coil part, 114…First magnet, 116…First plate, 118…Second plate, 120…First magnetic gap, 122…Second magnetic gap, 124…Region with greater magnetic resistance, 126…First recess, 128…Second recess, 150…Cap magnet, 152…Recess, 154…Pole piece component, 156…Intermediate coil part, 158…Attached coil part, 1 60…Second magnet, 162…Third magnet, 164…Third plate, 166…Region with greater magnetoresistance, 168…Third recess, 170…Axis, 172…Third magnetic gap, 200…Transducer assembly, 201…Transducer assembly, 300…Transducer assembly, 400…Transducer assembly, 500…Transducer assembly, 501…Transducer assembly, 600…Transducer assembly, 601…Transducer assembly, 700…Transducer assembly, 800…Transducer assembly

Claims

1. Pole piece and, A former arranged around the pole piece, A first coil portion and a second coil portion are arranged on the former and spaced apart from each other in the axial direction, wherein the first coil portion and the second coil portion are configured to direct the current in the same direction with respect to the cross-section, A magnetic structure disposed around the pole piece, comprising a magnet, a first plate, and a second plate, wherein the first plate provides a first magnetic gap having an axial gap length, and the second plate provides a second magnetic gap having the same axial gap length, and the first plate and the second plate cooperate to provide a region between the first magnetic gap and the second magnetic gap in which the magnetoresistance is greater than that in the first magnetic gap and the second magnetic gap, A transducer assembly comprising, Each of the first coil portion and the second coil portion has an axial coil length that is approximately equal to the sum of the axial length of the region where the magnetic resistance is greater and the axial gap length of the first magnetic gap or the second magnetic gap. When the transducer assembly is stationary, the first coil portion is configured to occupy approximately half of the axial gap length of the first magnetic gap, and the second coil portion is configured to occupy approximately half of the axial gap length of the second magnetic gap. The transducer assembly is configured to provide a substantially consistent speaker force coefficient over most of the stroke. Transducer assembly.

2. The transducer assembly according to claim 1, wherein the second plate is axially positioned between the first plate and the magnet.

3. The transducer assembly according to claim 1, wherein the radial distance between the pole piece and the first plate and the second plate in the first magnetic gap and the second magnetic gap is smaller than the radial distance between the pole piece and the first plate and the second plate in the region where the magnetoresistance is greater.

4. The transducer assembly according to claim 1, wherein at least one of the first plate and the second plate has a radial recess in the region where the magnetic resistance is greater.

5. The transducer assembly according to claim 4, wherein the recess is a notch.

6. The transducer assembly according to claim 1, wherein the first coil portion and the second coil portion are wound around a mandrel in the same coil direction.

7. The transducer assembly according to claim 1, wherein the first magnetic gap is radially positioned between the pole piece and the portion of the first plate closest to the pole piece.

8. The transducer assembly according to claim 7, wherein the second magnetic gap is radially positioned between the pole piece and the portion of the second plate closest to the pole piece.

9. Pole piece and, A former arranged around the pole piece, A first coil portion and a second coil portion are arranged on the former and spaced apart from each other in the axial direction, wherein the first coil portion and the second coil portion are wound in the same direction with respect to the cross-section, A magnetic structure disposed around the pole piece, the magnetic structure comprising: a magnet; a first plate providing a first magnetic gap having a first axial gap length; a second plate providing a second magnetic gap having a second axial gap length; and a region disposed between the first magnetic gap and the second magnetic gap, having a magnetic resistance greater than that in the first magnetic gap and the second magnetic gap. A transducer assembly comprising, When the transducer assembly is stationary, the first coil portion is configured to occupy approximately half of the first axial gap length of the first magnetic gap, and the second coil portion is configured to occupy approximately half of the second axial gap length of the second magnetic gap. Transducer assembly.

10. The transducer assembly according to claim 9, wherein a portion of the first plate is positioned radially outward of the second plate.

11. The transducer assembly according to claim 9, wherein the radial distance between the pole piece and the first plate in the first magnetic gap is smaller than the radial distance between the pole piece and the first plate in the region where the magnetoresistance is greater.

12. The transducer assembly according to claim 9, wherein the first plate has radial recesses in the region where the magnetic resistance is greater.

13. The transducer assembly according to claim 9, wherein the first magnetic gap is radially positioned between the pole piece and the portion of the first plate closest to the pole piece.

14. The transducer assembly according to claim 13, wherein the second magnetic gap is radially positioned between the pole piece and the portion of the second plate closest to the pole piece.

15. The central ferromagnetic component, A closed tubular member is arranged around the central ferromagnetic component, A first conductive coil portion and a second conductive coil portion are arranged on the tubular member and spaced apart from each other in the axial direction, wherein the first conductive coil portion and the second conductive coil portion are wound in the same direction, A magnetic structure disposed around the central ferromagnetic component, wherein the magnetic structure comprises a magnet, a first ferromagnetic element providing a first magnetic gap having a first axial gap length, a second ferromagnetic element providing a second magnetic gap having a second axial gap length, and a region disposed between the first magnetic gap and the second magnetic gap having a greater magnetoresistance than the magnetoresistance in the first magnetic gap and the second magnetic gap. A transducer assembly equipped with the following features.

16. The transducer assembly according to claim 15, wherein the radial distance between the central ferromagnetic component and the first ferromagnetic element in the first magnetic gap is smaller than the radial distance between the central ferromagnetic component and the first ferromagnetic element in the region where the magnetoresistance is greater.

17. The transducer assembly according to claim 15, wherein the first ferromagnetic element has radial recesses in a region where the magnetoresistance is greater.

18. The transducer assembly according to claim 15, wherein the first conductive coil portion has an axial coil length that is substantially equal to the axial length of the sum of the first axial gap length and the region with greater magnetic resistance.

19. The transducer assembly according to claim 15, wherein the first magnetic gap is radially positioned between the central ferromagnetic component and the portion of the first ferromagnetic element closest to the central ferromagnetic component, and the second magnetic gap is radially positioned between the central ferromagnetic component and the portion of the second ferromagnetic element closest to the central ferromagnetic component.

20. The transducer assembly according to claim 15, wherein the tubular member moves freely over a certain distance in response to an electrical signal applied to the first conductive coil portion and the second conductive coil portion.

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