Phase plug for compression driver

Abstract

A phase plug for a compression driver comprising a single piece body and at least one acoustic channel, the border forming at least a portion of the channel contained within the perimeter of the single piece body, while the remainder of the border is formed by the motor structure, wherein a continuous radial joint is provided between the single piece body and the motor structure to eliminate small contact points and prevent the phase plug from being displaced during assembly, such that the design enables a draftless molding while maintaining the acoustic channel geometry, and provides a stable mechanical reference surface to enable reliable long term attachment.

Description

[0001] Cross-citation of related applications

[0002] This U.S. non-provisional patent application claims the benefit and priority of U.S. Provisional Patent Application No. 63 / 753,191, filed February 3, 2025, entitled "Novel Multiple Channel Phase Plug for Compression Drivers," the entire contents of which are incorporated herein by reference. Technical Field

[0003] The embodiments relate to acoustic devices, specifically to phase plug assemblies for compression drivers used in professional audio applications. The phase plug assembly utilizes a novel mounting configuration that integrates a molded component with an electric motor structure to achieve improved mechanical stability and manufacturing efficiency of a one-piece phase plug. More specifically, the embodiments relate to a phase plug design in which a portion of the outer phase plug channel boundary is contained within the perimeter of the molded component, enabling continuous radial engagement contact. This improves the positioning accuracy and mating interface between the phase plug assembly and the compression driver motor assembly, which requires tight tolerances. Background Technology

[0004] Compression drivers are widely used in professional audio applications for high-frequency sound reproduction. Compression driver 10 includes ( Figure 1 The diaphragm assembly 12, the electric motor structure 14, and the phase plug 16 are described. The diaphragm assembly 12 comprises: a moving part (typically a thin plastic or metal dome or ring) attached to the voice coil; a clamping fixture positioning the diaphragm assembly within the air gap of the motor structure; and the phase plug 16, adjacent to and tightly spaced from the diaphragm assembly 12. The space between the outer surface of the diaphragm and the inner surface of the phase plug is called a compression chamber. The air trapped in the compression chamber has higher local stiffness near the diaphragm surface, which improves energy transfer from the diaphragm to the air. The phase plug 16 includes one or more acoustic channels 18. Figure 1 , Figure 3 These acoustic channels guide acoustic energy from the compression chamber to the driver's outlet 20. The phase plug's surface adjacent to the compression chamber has a series of openings or slits that allow sound to enter the acoustic channels. The slits are typically radial, but other geometries are sometimes present. In either case, they are typically radially distributed around the phase plug's central axis of rotation.

[0005] The compression cavity formed between the diaphragm and the phase plug has multiple resonant modes that depend on the cavity size within the audio frequency range. Since compression drivers are typically designed for frequency ranges up to 20 kHz, effective modal control is achieved by strategically arranging acoustic channels along the cavity boundaries to suppress modal behavior within specific frequency ranges. To prevent the excitation of these acoustic modes, the acoustic channels that allow sound to exit the compression cavity are positioned at nodal locations corresponding to the acoustic modes of the compression cavity. Larger diaphragms have larger compression cavities, more modes, and more acoustic channels to prevent mode excitation. A typical compression driver 10 ( Figure 1 , Figure 3 The driver 10 has one to four acoustic channels 18 from the compression chamber to the acoustic outlet 20. These channels 18 allow sound to propagate from the compression chamber, through the phase plug 16, to the acoustic outlet 20 of the driver. Downstream of the driver outlet 20 are typically impedance matching devices, such as horn, waveguide, or waveplate.

[0006] Traditional phase plug designs face significant manufacturing and assembly challenges. The complex channel geometry required to achieve optimal acoustic performance often includes features that overlap with themselves, such as inverted structures, which prevent the use of certain types of manufacturing processes (e.g., conventional injection molding). Therefore, many phase plugs must be divided into multiple parts and assembled (Figure 2). This increases cost, complexity, and can lead to tolerance accumulation problems. As seen in Figures 2(a) through (c), this prior art phase plug 16 has an outer portion 16' that receives an intermediate portion 16'', which in turn receives a center portion 16''', wherein the various parts are nested together to form an acoustic channel 18. Figure 2(c) shows the nested phase plug 16 disposed within a compression driver 10. A compression cavity 30 is formed between the diaphragm 12 and the nested phase plug 16. An air gap and voice coil 32 are disposed radially outside the phase plug 16 within an electric motor structure 14. The compression driver 10 is closed by a rear cover 34 on the opposite side of the acoustic outlet 20. In this prior art version, the outermost acoustic channel 24 of the phase plug 16 is formed within the phase plug itself and is formed by the inner surface of the outer portion 16' and the outer surface of the middle portion 16''. Therefore, when the phase plug 16 is disposed within the actuator 10, the outer surface of the outer portion 16' of the phase plug 16 engages with the electric motor structure 14 (FIG. 2(c)). This nested construction increases the number of components required to form the plug. The additional components may cause tolerance accumulation problems during assembly and engagement with the electric motor structure. Such prior art is used to achieve undercut structures or other features incompatible with typical mold manufacturing requirements.

[0007] One method for avoiding undercut structures is described in US 12,149,906 B2, where a helical acoustic channel can be successfully molded without undercut structures. However, even here, the final assembly consists of multiple parts that need to be assembled together. The more parts there are, the greater the potential for the accumulation of assembly and geometric errors.

[0008] The phase plug geometry is designed to minimize obstruction of acoustic energy as it passes through the acoustic channel. The assembly of the individual components of the phase plug (16', 16'', 16''' in Figure 2) is performed by positioning and securing one component inside another. To avoid obstructing airflow within the opening 18 of the phase plug, the contact points between the individual components forming the phase plugs 16', 16'', 16''' must be as small as possible.

[0009] In some cases, a phase plug geometry can be defined to avoid an undercut structure and allow for geometric integration, enabling them to be manufactured as a single component, such as the one-piece phase plugs of the prior art. As mentioned above, the mating and assembly features of these one-piece phase plugs are manufactured to be as small as possible to avoid acoustic obstruction. This requires the phase plug 16 to contact the motor structure at only a few small points 22, thus creating the possibility of mechanical instability ( Figure 3 (Refer to Figure 4). For these molded one-piece phase plugs 16 designed in the prior art, the outermost phase plug acoustic channel 24 is formed by two separate assemblies adjacent to each other. The outer surface of the outer acoustic channel 24 is defined by the inner surface 26 of the electric motor assembly 14; the inner surface of the acoustic channel 24 is defined by the outer wall 28 of the one-piece phase plug 16. Here, the phase plug 16 is supported on the inner surface 26 of the electric motor structure 14 by a connecting element 22 extending from the outer wall 28 of the phase plug 16 (Figure 4(b)).

[0010] This prior art version can be described as follows: the inner surface 26 of the motor 14 forms a "basket" for arranging the phase plug 16 ( Figure 3 (See Figure 4). The basket of the motor structure is typically contacted by contact points 22 of the phase plug 16. These contact points are typically three or four small ribs or pins extending from the outer wall 28 of the phase plug 16, displacing the phase plug 16 a short distance from the motor assembly 14 to form the outermost acoustic channel 24.

[0011] The limited contact area between the protruding portion and the motor basket in existing technologies can introduce positioning mechanical errors during assembly. Eccentricity, misalignment height, or tilt displacement of the phase plug within the motor structure can cause the compression chamber position and dimensions to exceed tolerances. This can degrade acoustic performance and may even lead to mechanical interference with the diaphragm. Furthermore, the minimum surface area of ​​the protruding portion may not provide sufficient area for a reliable, long-term attachment of the integral phase plug to the motor.

[0012] Existing manufacturing methods struggle to balance the conflicting requirements of molding feasibility and acoustic channel optimization. The draft angle required for component demolding can affect channel geometry, while the design without undercuts can limit acoustic performance. The challenge lies in achieving a more optimized channel shape while maintaining integral moldability and reliable attachment to the motor structure. Summary of the Invention

[0013] To address the problems of existing technologies, this invention provides a novel phase plug assembly design that enables one-piece molding while offering improved mechanical attachment, fit tolerances, and acoustic performance. This design repositions a portion of the phase plug's outer channel boundary to the molded component. This creates a larger contact surface with a continuous radial perimeter between the phase plug and the electric motor structure. The result is a larger adhesive or other attachment area, improved assembly reference, and a lower probability of errors during assembly.

[0014] The phase plug assembly comprises a single molded part having one or more acoustic channels configured to guide acoustic energy from the diaphragm through the phase plug to the compression driver outlet. A portion of the outermost acoustic channel boundary is contained within the perimeter of the molded body, while any remaining external channel boundaries are defined by the geometry of the motor structure. The monolithic component body incorporates an appropriate draft angle suitable for component extraction while maintaining the acoustic channel geometry through strategically dividing the overall acoustic channel path between the phase plug and the motor sub-assembly.

[0015] This configuration achieves a continuous radial engagement between the phase plug and the motor structure. Compared to the protruding portions used in existing technologies, the radial engagement provides a substantially larger attachment area. This ensures reliable, long-term attachment during operation. Furthermore, configuring the attachment position continuously in the radial direction enables a stable arrangement and automation for dispensing adhesives or other bonding agents.

[0016] Unlike existing designs that require multiple sub-assemblies or compromise mounting methods, this design achieves both improved acoustic channel geometry and robust mechanical design through a single-piece body component suitable for injection molding. Attached Figure Description

[0017] To gain a more complete understanding of this disclosure, reference is now made to the following brief description taken in conjunction with the accompanying drawings and detailed description, wherein like reference numerals denote like parts, in the drawings: Figure 1 This is an exploded view of a prior art compression drive assembly, showing the phase plug, motor structure, and diaphragm components of the compression drive; Figures 2(a) through (c) show various views of prior art multichannel phase plug assemblies including multiple nested sub-components; Figure 3 This is a cross-sectional view of a prior art integral phase plug arranged inside the structure of a compression drive motor. It shows the external passage defined by both the motor structure and the molded part; Figure 4(a) and (b) are perspective and cross-sectional views showing the protruding portion extending from the surface of a prior art one-piece body phase plug; Figure 5 This is a cross-sectional view of an integrated phase plug implementation, showing a portion of the outermost acoustic channel contained within the molded part; Figure 6 This is a partial cross-sectional view and a partial enlarged view of an embodiment of the integrated phase plug, showing the mating surface and reference surface according to the embodiment; Figure 7 This is a top view of the integrated phase plug; Figure 8 This is a bottom view of an integrated phase plug; Figure 9 This is a cross-sectional view of the mold in the closed position during the formation of the single-piece body of the phase plug assembly; Figure 10 This is a cross-sectional view of the mold in the open position, showing the removal of the integral component from which the phase plug was formed; Figure 11 yes Figure 5 A cross-sectional view of the integrated phase plug in an alternative implementation with a single acoustic channel; Figure 12 It shows Figure 11 A partially enlarged view of the phase plug installed in the electric motor structure of the compression driver; Figure 13 yes Figure 11 A top view of the phase plug; and Figure 14 yes Figure 11 A bottom view of the phase plug. Detailed Implementation

[0018] Figures 5 to 8 A cross-sectional view, a top view, and a bottom view of a novel integral component phase plug 100 according to an exemplary embodiment of the present invention are shown. The phase plug 100 is configured to be operatively disposed within a compression actuator having an electric motor structure 110. The phase plug 100 forms a compression cavity 102 with a vibrating diaphragm 104. Specifically, the boundary surface 106 of the phase plug 100 is arranged adjacent to the inner surface 108 of the diaphragm 104 to form the compression cavity 102 therebetween. The compression actuator includes a single acoustic outlet 112 defined by the end of the phase plug 100. The phase plug 100 includes at least one acoustic channel 114 that extends from the compression cavity 102 through the phase plug 100 and terminates at the acoustic outlet 112. Figure 6 In a preferred embodiment, the phase plug 100 includes an inner channel 114a and an outer channel 114b. Both the inner channel 114a and the outer channel 114b extend about the central rotation axis AA of the phase plug 100, wherein the outer channel 114b is arranged radially outside the inner channel 114a.

[0019] The central axis of rotation AA is defined within the phase plug 100 and extends from the boundary surface 106 at the compression cavity 102 of the phase plug 100 to the acoustic outlet 112. The phase plug 100 is arranged symmetrically around the axis of rotation AA.

[0020] As shown in the figure, the phase plug 100 includes a single-piece body 100'. That is, the body 100' of the phase plug 100 is a single-piece component and can be molded into a single unit without the need to manufacture and assemble multiple parts.

[0021] The acoustic channel 114 passes through the monolithic body 100' of the phase plug 100 and extends between the corresponding inlet 116 at the boundary surface 106 of the phase plug 100 and the end 118 of the acoustic channel 114 at the acoustic outlet 112.

[0022] The external acoustic channel 114b extends from the channel inlet 116 at the boundary surface 106 of the phase plug 100 to the acoustic channel outlet 118 at the single acoustic outlet 112 of the phase plug 100. Along this extension direction, the external acoustic channel 114b is defined by the outer surface 120 of the phase plug 100' and the outer surface 122 of the electric motor structure 110. Specifically, see... Figure 6 This differs from the internal acoustic channel 114a, which is entirely defined by the material forming the phase plug 100.

[0023] Importantly, the one-piece body 100' of the phase plug 100 is formed without undercuts to allow for easy demolding from the mold during manufacturing.

[0024] As previously described, the phase plug 100 is formed from a single, one-piece body 100'. This one-piece body 100' comprises two regions: a central region 124 and a radial interface region 126. A plurality of connecting elements 128 can act as bridges between the central region 124 and the radial interference region 126. Figure 8 ).

[0025] The central region 124 includes a dome-shaped surface on one side comprising a boundary surface 106 containing a phase plug 100, and on the opposite side includes a spherical portion extending into a single acoustic outlet 112. The central region may be a solid blocking element, or it may include one or more acoustic channels 114 that extend symmetrically about axis AA and from the compression chamber 102 to the single acoustic outlet 118 to allow acoustic energy from the compression chamber 102 to radiate to the outlet 112. The central region 124 also includes the outer surface 120 of the phase plug 100, and thus, together with the outer surface 122 of the electric motor structure 110, serves to define the outer acoustic channel 114b.

[0026] Radial interference region 126 extends symmetrically about axis AA radially outward from central region 124. The shape and configuration of region 126 are designed to generally provide interference between phase plug 100 and compression drive motor structure 110. That is, radial interference region 126 defines a continuous radial engagement extending substantially the entire perimeter of the phase plug attachment interface. This continuous radial engagement provides an expanded contact surface between phase plug 100 and motor structure 110 while still maintaining a continuous engagement interface around the perimeter of the phase plug attachment point. This is achieved by substantially repositioning the external acoustic channel 114b within the injection-molded phase plug monolithic body 100', in contrast to the prior art, which either forms the external channel by nesting multiple components to form the phase plug (FIG. 2) or relies on external contact points supporting the phase plug within the basket of the motor structure. Figure 3 (See Figure 4). That is, in this embodiment, the outermost acoustic channel 114b is contained within the perimeter of the molded phase plug monolithic body 100'. Here, the outermost acoustic channel 114b is defined on the one hand by the outer surface 120 of the phase plug 100, and on the other hand by the outer surface 122 of the electric motor structure 122. However, due to the radial interference region 126, the outermost perimeter of the phase plug 100 extends outward beyond the outermost acoustic channel 114b and forms a mating surface with the electric motor structure 122, which can receive and retain adhesive to seal the phase plug 100 to the motor 122.

[0027] like Figure 6As shown in detail, at the boundary between the phase plug 100 and the motor structure 110, the radial interference region 126 has at least one reference surface 130, which defines an attachment surface between the phase plug body 100' and the motor structure 110. In one embodiment, the reference surface 130 may include a first generally planar surface 132 arranged generally transverse to the axis AA, wherein the first planar surface 132 extends around the perimeter of the phase plug 100. The reference surface 130 may also include a second generally planar surface 134 arranged generally parallel to the axis AA, wherein the second planar surface 134 also extends around the perimeter of the phase plug 100. A relief 136 may be located at the intersection of the first planar surface 132 and the second planar surface 134. The relief 136 may include a surface arranged at an angle at both the first planar surface 132 and the second planar surface 134, such that the two surfaces are abutted at an angle. The recess 136 may additionally or alternatively include a curved surface, or may include a curved or straight groove adjacent to the first planar surface 132 and the second planar surface 134.

[0028] The recess 136 extends around the periphery of the phase plug 100 about an axis AA and is configured to receive a volume of adhesive material sandwiched between the mating surface of the radial interference region 126 of the phase plug 100 and the corresponding surface of the electric motor structure 110. The recess 136 essentially includes a gap, groove, inclined surface, or the like positioned adjacent to the mating surfaces of the phase plug body 100' and the motor structure 110.

[0029] The shape, size, and configuration of the reference surface 130 are designed to prevent the phase plug body 100 from rotating and / or translating relative to the motor structure 110 during compression drive operation. This is primarily achieved through the engagement of the first planar surface 132 and the second planar surface 134 with corresponding surfaces of the electric motor structure 110.

[0030] The first planar surface 132 of the reference surface 130 engages with a corresponding first planar surface 138 of the electric motor structure 110. This surface 138 extends in a similar manner to the first planar surface 132; that is, in one direction, the planar surface 138 extends transversely to the axis AA, and in another direction, it extends around the perimeter of the phase plug 100. Friction between the first planar surface 132 of the phase plug 100 and the corresponding planar surface 138 of the motor structure 110, and / or the application of an adhesive between them, prevent rotational movement of the phase plug 100 on the planar surface of the electric motor structure 110.

[0031] The second planar surface 134 of the reference surface 130 engages with a corresponding second planar surface 140 of the electric motor structure 110. This surface 140 extends in a similar manner to the second planar surface 134; that is, in one direction, the planar surface 140 extends parallel to the axis AA, and in another direction, it extends around the perimeter of the phase plug 100. Friction between the second planar surface 134 of the phase plug 100 and the corresponding planar surface 140 of the motor structure 110, and / or the application of an adhesive therebetween, prevents rotational movement of the phase plug 100 on the planar surface of the electric motor structure 110. Furthermore, the engagement of the second planar surface 134 of the phase plug 100 with the corresponding surface 140 of the electric motor 110 prevents lateral movement of the phase plug 100 relative to the motor 110.

[0032] The second surface 134 of the phase plug 100 and the corresponding second surface 140 of the electric motor 110 are described herein as “planar”. This refers to the planar shape of surfaces 134 and 140, such as… Figure 6 As shown in the cross section. Of course, surfaces 134 and 140 have curvature on another axis that causes surfaces 134 and 140 to extend circumferentially around axis AA.

[0033] The fixing of the phase plug 100 and the electric motor structure 110 is described herein as being facilitated by an adhesive, for example, applied at the recess 136 and / or between surfaces 132, 138 and / or between surfaces 134, 140. In other embodiments, fixing may alternatively or additionally be accomplished by mechanical engagement and / or by friction fit.

[0034] As previously mentioned, by aligning the outer surface 120 of the phase plug 100 with the outer surface 122 of the electric motor structure 110 ( Figure 6The phase plug 100, positioned within the electric motor structure 110, defines at least the outermost acoustic channel 114b. The phase plug 100 may include the outermost channel 114b as the only acoustic channel extending through it. In other embodiments, the phase plug 100 may include one or more internal acoustic channels 114a. For example, the phase plug may include: a first internal acoustic channel concentrically arranged around the phase plug axis AA; and a second internal acoustic channel also concentrically arranged around the phase plug axis AA and located radially outside the first internal acoustic channel but radially inside the external acoustic channel. In this manner, the phase plug may include a third internal acoustic channel and a fourth internal acoustic channel, etc., each additional internal acoustic channel concentrically arranged around the phase plug axis AA and located radially outside the first internal acoustic channel but radially inside the external acoustic channel. The internal acoustic channels 114a and external acoustic channels 114b of the phase plug 100 extend in one direction from the boundary surface 106 of the phase plug 100 to a single acoustic outlet 118, and in another direction circumferentially around the axis AA.

[0035] The first planar surface 132 and the second planar surface 134 of the radial interference region 126 of the phase plug 100 have been described so far as perpendicular to and parallel to the axis AA, respectively. This orientation is, of course, exemplary. In other embodiments, one or more of the first surface 132 and the second surface 134 of the interference region 126 may be oriented at an angle relative to the axis AA. Corresponding surfaces 138, 140 of the motor structure 110 may similarly be oriented at an angle relative to the axis AA. Furthermore, the first surface 132 and the second surface 134 of the interference region 126 and the corresponding surfaces 138, 140 of the electric motor 110 have been described so far as planar. This is again merely exemplary. These surfaces can take any shape, as long as sufficient to facilitate the desired engagement between the phase plug 100 and the electric motor 110.

[0036] In one embodiment, at least one of the acoustic channels 114 of the phase plug 100 has a circular or annular cross-section at the boundary surface 106 of the phase plug 100. In another embodiment, at least one of the acoustic channels has dimensions and / or arrangement around the axis of rotation AA to allow modal control of the acoustic modes within the compression chamber 102. In yet another embodiment, the cross-sectional area of ​​at least one of the channels 114 expands between the corresponding inlet 116 at the boundary surface 106 of the phase plug 100 and the end 118 at the acoustic outlet 112.

[0037] In an exemplary preferred embodiment, the one-piece body phase plug includes a multi-channel (>1 channel) phase plug for a compression actuator, wherein the phase plug is processed by injection molding, the phase plug is processed into a one-piece, the external acoustic channels of the phase plug are contained within the perimeter of the molded part and have an inner boundary defined by the phase plug and an outer boundary defined by the ferrous motor structure, wherein the joint between the phase plug and the motor structure must be radially continuous, including at least one reference surface defined by the mating surfaces between the injection-molded phase plug and the ferrous motor structure, and must be configured to accommodate the volume of adhesive material sandwiched between the mating surfaces.

[0038] Figures 9 to 10 An exemplary mold 150 for injection molding a phase plug 100 is shown. The mold 150 includes two halves 152, 154, which, when in a closed position ( Figure 9 The mold 150 and molded material are combined to form an internal cavity 156 with a negative shape and a phase plug 100. When the mold 150 is in the closed position, the injection molding material is inserted into the internal cavity 156. Upon completion of curing, the mold 150 moves to the open position and the fully formed phase plug 100 is removed without any undercut. The phase plug 100 has a draft taper to facilitate demolding from the mold 150. Figures 9 to 10 This demonstrates how this embodiment can be easily removed from the mold due to the simple parting line and sufficient draft angle.

[0039] Phase plug 100 has been referenced Figures 5 to 8 The diagram schematically depicts two acoustic channels: an inner acoustic channel 114a and an outer acoustic channel 114b. The outer acoustic channel is located radially outside the inner acoustic channel 114a and is partially formed by the motor structure of the compression driver housing the phase plug 100. This channel configuration is exemplary. The broad scope of the invention encompasses both cases where the phase plug has fewer than two acoustic channels and cases with more than two acoustic channels.

[0040] Figures 11 to 14 An alternative embodiment of the phase plug 100 is shown, which includes an external acoustic channel 114b but omits the internal acoustic channel 114a. That is, Figures 11 to 14 The phase plug 100 includes a single-piece body 100' formed by a central region 124 and a radial interference region 126, the radial interference region 126 being connected to the central region 124 via multiple connecting elements 128. Here, the central region 124 is essentially a solid occluder without any channels passing through it. An external acoustic channel 114b is the only channel forming through the plug body 100' and is arranged within the perimeter of the plug body 100'. This channel 114b is formed on one hand by the outer surface 120 of the central region 124 of the phase plug 100, and on the other hand by the outer surface 122 of the electric motor structure 110. Specifically, see Figure 12 The radial interference region 126 extends radially outward from the acoustic channel 114b, and in the manner previously described and in... Figure 6 and Figure 12 The manner shown in the diagram facilitates the engagement of the phase plug 100 with the electric motor structure 110.

[0041] The embodiments of the invention described herein address the shortcomings of prior art phase plug designs by introducing a one-piece (i.e., monolithic) molded phase plug that integrates internal and external acoustic channels within its body, while strategically repositioning a portion of the outermost channel boundary to the molded component itself. This design enables the formation of a continuous radial engagement between the phase plug and the motor structure, providing a substantially larger and more stable attachment system compared to the discrete contact points or multi-part assemblies found in conventional designs. The described configuration ensures precise positioning and robust mechanical integration, reduces tolerance challenges, and facilitates reliable engagement while maintaining optimal acoustic channel geometry and compatibility with standard molding processes. Therefore, the invention achieves improved manufacturing efficiency, mechanical stability, and acoustic performance, effectively overcoming the inherent cost, complexity, and reliability issues of conventional phase plug assemblies.

[0042] Various embodiments of the invention are described herein with reference to the accompanying drawings. Alternative embodiments may be devised without departing from the scope of the invention. It should be noted that various connections and positional relationships (e.g., above, below, adjacent, etc.) are depicted between elements in the description and in the drawings. Unless otherwise stated, these connections and / or positional relationships may be direct or indirect, and the invention is not intended to be limiting in this respect. Thus, the connection of entities may refer to direct or indirect connection, and the positional relationship between entities may be direct or indirect positional relationship.

[0043] The term "exemplary" is used herein to mean "serving as an example, instance, or illustration." Any implementation or design described herein as "exemplary" is not necessarily to be construed as being more preferred or advantageous than other implementations or designs. The terms "at least one" and "one or more" are understood to include any integer greater than or equal to one, i.e., one, two, three, four, etc. The term "multiple" is understood to include any integer greater than or equal to two, i.e., two, three, four, five, etc. Terms such as "connected to" and "attached to" can include both indirect "connection" and direct "connection."

[0044] Various embodiments of the invention have been described for illustrative purposes, but are not intended to be exhaustive or limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein has been chosen to best explain the principles of the embodiments, their practical application, or technical improvements to technologies found in the market, or to enable those skilled in the art to understand the embodiments disclosed herein.

Claims

1. A phase plug for a compression drive having an electric motor structure, the phase plug comprising: a. A compression chamber formed by a vibrating diaphragm and a phase plug at a boundary surface adjacent to the diaphragm; b. A single acoustic outlet, defined by the end of the phase plug; c. An internal acoustic channel and an external acoustic channel each originate from the compression cavity, pass through the phase plug, and terminate at the acoustic outlet; as well as d. A rotation axis defined within the phase plug, the rotation axis extending from the boundary surface of the phase plug at the compression chamber to the acoustic outlet; e. Wherein, the phase plugs are arranged symmetrically about the axis of rotation; f. Wherein, the phase plug comprises a single-piece body; g. Wherein, the internal acoustic channel and the external acoustic channel extend between the corresponding inlets of the phase plug located at the boundary surface and the corresponding ends located at the acoustic outlet; and h. Wherein, both the internal acoustic channel and the external acoustic channel are defined within the outer periphery of the phase plug in the single-piece body; i. Wherein, the external acoustic channel is formed by the outer surface of the single-piece main body and the outer surface of the electric motor structure; and j. Wherein, the single-piece main body is formed by molding and has no undercut structure.

2. The phase plug according to claim 1, wherein, The phase plug includes a central region and a radial interference region located radially outside the central region, wherein the radial interference region engages the electric motor structure.

3. The phase plug according to claim 2, wherein, The radial interference region includes a continuous radial joint that extends substantially around the entire perimeter of the phase plug.

4. The phase plug according to claim 2, wherein, The radial interference region includes at least one reference surface, which defines the attachment surface between the monolithic body and the electric motor structure.

5. The phase plug according to claim 1, wherein, At least one of the internal acoustic channel and the external acoustic channel has a circular or annular cross-section at the boundary surface of the phase plug.

6. The phase plug according to claim 5, wherein, The dimensions of at least one of the internal acoustic channel and the external acoustic channel, and their arrangement around the axis of rotation, allow for modal control of the acoustic modes of the compression chamber.

7. The phase plug according to claim 3, wherein, The bonding between the single-piece main body and the electric motor structure is achieved through adhesive and / or mechanical bonding.

8. The phase plug according to claim 7, wherein, The joint between the single-piece body and the electric motor includes at least one recess to accommodate the volume of adhesive material sandwiched between the mating surfaces.

9. The phase plug according to claim 8, wherein, The recess includes a gap positioned adjacent to the mating surface between the monolithic body and the electric motor structure.

10. The phase plug according to claim 8, wherein, The recess includes a circumferential groove formed in at least one of the one-piece body and the electric motor structure.

11. The phase plug according to claim 2, wherein, The at least one reference surface prevents the monolithic body from undergoing translational and / or rotational displacement relative to the electric motor structure during operation.

12. The phase plug according to claim 1, wherein, The cross-sectional area of ​​at least one of the internal channel and the external channel expands between the corresponding inlet of the phase plug at the boundary surface and the end located at the acoustic outlet.

13. The phase plug according to claim 1, wherein, The monolithic body also includes multiple connecting elements that extend between the central region and the radial interference region to provide structural reinforcement.

14. The phase plug according to claim 1, wherein, The phase plug is configured such that the internal acoustic channel and the external acoustic channel are located at the node positions of the acoustic modes of the compression chamber.

15. The phase plug according to claim 4, wherein, The reference surface includes: a first planar surface generally transverse to the axis of rotation; a second planar surface generally parallel to the axis of rotation; and a recess extending between the first planar surface and the second planar surface and configured to receive and retain adhesive, the first planar surface, the second planar surface, and the recess extending continuously around the periphery of the phase plug.

16. The phase plug according to claim 4, wherein, The reference plane is configured to fix the monolithic body to the electric motor structure, and to position the outer surface of the monolithic body adjacent to the outer surface of the electric motor structure to form the external acoustic channel.

17. The phase plug according to claim 1, wherein, The internal acoustic channel includes a plurality of channels arranged concentrically around the axis of rotation, each of the plurality of channels extending from the compression chamber through the phase plug and terminating at the acoustic outlet.

18. A phase plug for a compression driver, comprising: A single-piece main body is configured to be housed within a compression drive with an electric motor structure; At least one external acoustic channel extends from the boundary surface adjacent to the diaphragm through the monolithic body to the acoustic outlet; Wherein, a portion of the outer boundary of the external acoustic channel is defined by the single-piece body, and the remaining portion of the outer boundary of the external acoustic channel is defined by the electric motor structure; The single-piece main body is formed by molding and has no undercut structure; The single-piece body includes a continuous mating surface configured to engage the electric motor structure around the periphery of the phase plug; and The continuous mating surface is disposed on the radially outer side of the external acoustic channel.

19. The phase plug according to claim 17, wherein, The continuous engagement surface includes a recess configured to receive and retain adhesive to secure the one-piece body to the electric motor structure, and wherein the shape and configuration of the continuous engagement surface are designed to prevent lateral and rotational movement of the one-piece body when secured to the electric motor structure.

20. The phase plug of claim 18, further comprising an internal acoustic channel extending from the boundary surface adjacent to the diaphragm through the monolithic body to the acoustic outlet, the internal acoustic channel being disposed radially inside the external acoustic channel.

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