Abstract
A speaker driver with a high degree of symmetry for use in a loudspeaker is disclosed. The disclosed motor assembly may be symmetrical about its long and radial axes. A voice coil disclosed may be supported by opposing upper and lower suspension members on the voice coil upper and lower ends. The upper and lower voice coil suspension members disclosed may be adhered to a frame above and below the motor assembly, respectively in a mirror like fashion being symmetrical about their long and radial axes. An open voice coil frame disclosed may use elongate structural members having a shape similar to the letter j (j-beams) defining large interconnected air gaps to promote cooling of the voice coil.
Claims
1. A speaker driver comprising: (a) a frame; (b) a motor assembly disposed within said frame, said motor assembly having a first magnet system polarized along the radial axis of the speaker driver, the first magnet system comprising permanent magnetic material and non-ferromagnetic material and a second magnet system polarized along the radial axis of the speaker driver, the second magnet system comprising permanent magnetic material and non-ferromagnetic material, the first and second magnet systems being concentrically arranged to form a magnetic gap wherein the length of the first and second magnet systems are substantially equal to the length of the magnetic gap; (c) a voice coil, said voice coil comprising a winding and a former, disposed moveably within a magnetic gap formed within said motor assembly; (d) an upper suspension member adhered to said frame and said former above said motor assembly for supporting said voice coil and a cone; (e) a lower suspension member adhered to said frame and said former below said motor assembly for supporting said voice coil and said cone; and wherein said cone is adhered to said upper suspension.
2. The speaker driver of claim 1 wherein said winding is exposed excepting the length of said magnetic gap.
3. The speaker driver of claim 1 wherein said upper suspension and said lower suspension are disposed substantially equidistant from said first and second magnetic systems along said long axis of said speaker driver and wherein said upper and lower suspension members have opposing mirrored shapes.
4. The speaker driver of claim 1 having a single voice coil which is not characterized as a split gap voice coil.
5. The speaker driver of claim 1 wherein said motor assembly is magnetically symmetrical about a long axis and radial axis of said speaker driver.
6. The speaker driver of claim 1 wherein the first and second magnet systems comprise a plurality of arc magnets having shoulder portions magnetically joined forming a first and second annular ring.
7. The speaker driver of claim 6 wherein said shoulder portions have at least one protruding area and at least one recessed area mated for magnetically interlocking said plurality of arc magnets.
8. The speaker driver of claim 1 wherein said frame comprises a plurality spaced apart j-beams disposed for providing air gaps between said j-beams substantially from an upper end of said frame to a lower end of said frame exterior to said voice coil and between said j-beams interior to said voice coil.
9. The speaker driver of claim 1 wherein the frame is characterized by an open structure exposing said voice coil.
10. A speaker driver of claim 1 wherein said speaker driver is characterized by an open coil frame design having an absence of material proximate said voice coil such that over about 50% of a winding area of said voice-coil is exposed for cooling.
11. A speaker driver of claim 1, said speaker driver having over from about 50% to about 95% of a winding area of said voice-coil is exposed.
12. The speaker driver of claim 1 wherein the upper suspension member and the lower suspension member have opposing mirrored shapes disposed substantially equidistant from the first and second magnetic systems.
13. The speaker driver of claim 1 wherein said frame is characterized by an open structure configured to expose an inner surface of said voice coil and an outer surface of said voice coil used in operation within said magnetic gap of said speaker driver.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) The advantages and further aspects of the disclosure will be readily appreciated by those of ordinary skill in the art as the same becomes better understood by reference to the following detailed description when considered in conjunction with the accompanying drawings, not drawn to scale, in which like reference characters designate like or similar elements throughout the several figures of the drawing and wherein:
(2) FIG. 1 is a cross-sectional view of one embodiment of a speaker driver of this disclosure.
(3) FIG. 1A is a cross-sectional view of an embodiment of a speaker driver of this disclosure using a multiple roll suspension.
(4) FIG. 1B is a detail of FIG. 1 expanded to illustrate the voice coil placement, including its winding and former, within the magnetic gap formed within the first and magnet systems of the motor assembly and polarities of the radial magnet.
(5) FIG. 2 is a cross-area view of another embodiment of a speaker driver of this disclosure illustrating use of fasteners on the left side of the long axis and adhesive attachment on the right.
(6) FIG. 3 is a cross-area view of FIG. 2 taken along line 3-3.
(7) FIG. 3A is a detail of FIG. 3 expanded to illustrate the voice coil placement within the magnetic gap.
(8) FIG. 4 is a cross-sectional side view of a motor assembly of this disclosure.
(9) FIG. 4A is an expanded view of a portion of an embodiment of a motor assembly illustrating the magnetic flux lines between the magnet systems of a motor assembly of this disclosure.
(10) FIG. 4B is a cross-sectional top view of a motor assembly of this disclosure.
(11) FIG. 5 is a cross-sectional view of an embodiment of a voice coil support system of this disclosure.
(12) FIG. 6A is a cross-sectional top view of an embodiment of an outer ring of a frame embodiment of this disclosure having a hoop and spoke configuration.
(13) FIG. 6B is a cross-sectional top view of an inner ring of a frame embodiment of this disclosure.
(14) FIG. 6C is a cross-sectional top view of an upper ring of a frame embodiment of this disclosure.
(15) FIG. 6D is a cross-sectional top view of a lower ring of a frame embodiment of this disclosure.
(16) FIG. 6E is a cross-sectional side view of a j-beam of a frame embodiment of this disclosure.
(17) FIG. 6F is a top view of an assembled frame embodiment of this disclosure using six j-beams.
(18) FIG. 7 is a cross-sectional view of an embodiment of an assembled frame of this disclosure using four j-beams.
(19) FIG. 8 is a cross-sectional view of a prior art speaker driver.
(20) FIG. 8A is an expanded view of a portion of a prior art speaker illustrating inward excursion of the voice coil.
(21) FIG. 8B is an expanded view of a portion of a prior art speaker illustrating outward excursion of the voice coil.
(22) FIG. 9 is a front view of one embodiment of a speaker driver of this disclosure using an open coil design.
(23) FIG. 10 is a perspective view of one embodiment of a speaker driver frame of this disclosure using an open coil design, which illustrates j-beams with integral hook areas.
(24) FIG. 10A is a bottom view of one embodiment of a speaker driver frame of this disclosure using an open coil design, which illustrates j-beams with integral hook areas.
(25) FIG. 10B is a top view of one embodiment of an outer ring with standoff plates.
(26) FIG. 11 is a perspective view of one embodiment of a speaker driver frame with a base ring.
(27) FIG. 12A is a partial perspective view of one embodiment of a speaker driver, which illustrating the open voice coil frame; the symmetrical voice coil suspension system using spiders for supporting the voice coil and cone; and the first and second magnet systems.
(28) FIG. 12B is a cross-sectional top view of a motor assembly of this disclosure.
(29) FIG. 12C is a detail of one embodiment of a motor assembly in which the first and second magnet systems illustrated are supported by the outer and inner rings with disposed voice coil. The polarities of the radial permanent magnets are also illustrated.
(30) FIG. 13 is a perspective view of two radially polarized magnets with shoulders, protrusions and recesses.
(31) FIG. 14A is a perspective view of an upper suspension member illustrating the difference in diameters between the outer portion of a half roll suspension and the inner portion of a half roll suspension.
(32) FIG. 14B is another perspective view of an upper suspension member illustrating the difference in diameters between the outer portion of a half roll suspension and the inner portion of a half roll suspension.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
(33) The present disclosure in broad aspects, relates to a speaker driver. In other aspects, it relates to a motor assembly, a voice coil support system and a frame, which may be used in the driver. The present disclosure is susceptible to embodiments of different forms. There are shown in the drawings, which will be described herein in detail, specific embodiments of the present disclosure with the understanding that the present disclosure is to be considered an exemplification of the principles of the disclosure and is not intended to limit the disclosure to that illustrated and described herein. The use of upper, lower, inner, outer, top, bottom, inside, outside, inward, upward and the like refer to the orientation of the speaker driver as it appears in the Figures. Further, while embodiments may be described as having one or more features or a combination of two or more features, such a feature or a combination of features should not be construed as essential unless expressly stated as essential.
(34) Referring now to the drawings, two alternative embodiments of the speaker driver 1 are illustrated in FIG. 1 and FIG. 1A. FIG. 1 is a cross-sectional view of one embodiment of the disclosed speaker driver 1. The speaker driver 1 includes a frame 2; a motor assembly 4; a voice coil 10, an upper suspension 14, a lower suspension 16 and a cone 18. The concentrically disposed voice coil 10 is typically made by winding wire around a bobbin, known as the winding 11 and former 12, respectively. The winding comprising at least one wire wound about the former 12 leaves the upper end and lower ends 10a, 10b ends of the voice coil 10 bare for adhesion to the suspension members 14, 16 and the cone 18. In aspects, the voice coil 10 of embodiments of this disclosure may be inside coils (not shown), outside coils or inside outside voice coils (not shown). The motor assembly 4 comprises two annular magnet systems 24, 26 concentrically disposed within the frame 2. The voice coil 10 is shown substantially bisecting a magnetic gap 5 formed between the two magnet systems 24, 26.
(35) Continuing, FIG. 1 illustrates another embodiment having an upper suspension 14 and lower suspension 16 adhered to the upper and lower ends of the frame 2a, 2b on opposite sides of the motor assembly 4. Suspension members typically used in the art are commonly called surrounds and spiders. Surrounds are generally made from a foam or butyl rubber. Surrounds may have be cupped, flat, corrugated or have progressive rolls. A preferred arcuate shape for a surround may be a half-roll, but more preferably progressive rolls. Spiders are typically corrugated and made from a stiffer material, preferably fabrics such as cotton, polypropylene or Nomex. FIG. 1A illustrates an embodiment having corrugated suspension members. A preferred embodiment may use spiders of Nomex having progressive rolls. Both suspension types have inner and outer circumferential edges for adhesion to the voice coil 10 and frame 2, respectively. As illustrated in FIG. 1 and FIG. 1A, the upper 14, 14 and lower suspension members 16, 16 of these embodiments may be respectively adhered between the voice coil 10 at the upper and lower ends 10a, 10b of the voice coil 10 and frame 2 on opposite sides of the motor assembly 4 allowing the voice coil 10 to move up and down the long axis 40. FIG. 1 and FIG. 1A also illustrate use of opposing suspension members 14, 16. The suspension members 14, 16 may have arcuate shapes, which mirror each other symmetrically about the long and radial axes 40, 39 of the speaker driver 1. In another embodiment, the upper suspension 14 may be adhered to the outer periphery 10d of the voice coil 10 and the frame 2 above the motor assembly 4. In a further aspect of this embodiment, the lower suspension 16 may be adhered to the outer periphery 10d of the voice coil 10 and the frame 2 below the assembly 4.
(36) The motor assembly 4 illustrated in FIG. 1 comprises two permanent annular ring magnets systems disposed concentrically within the frame 2. The permanent annular ring magnets systems 24, 26 may be high-grade ferrite, strontium or AlNiCo alloys; however, neodymium is preferred. The first magnet system 24 may be disposed outside the second magnet system 26. An embodiment of the motor assembly 4 illustrated in FIG. 1 is symmetrical about the long axis 40 and radial axis 39 of the speaker driver 1. Unlike prior art speaker drivers, having magnetic return paths through magnetically conducting top plates, pole pieces and sidewalls, preferred embodiments of this disclosure may use materials which do not conduct magnetically. The result may be a substantially symmetrical magnetic flux within the magnetic gap as depicted in FIG. 4A. FIG. 1 also illustrates an embodiment of an overhung voice coil 10 wherein the amount of winding 11 above and below the motor assembly 4 about the long axis 40 of the driver 1 may be substantially equal. When electrically excited, the amount of winding within the magnetic flux may be substantially constant resulting in an electrically symmetrical motor assembly 4.
(37) The cone 18 of the driver 1 may be circumferentially adhered to the inner periphery 10c of the voice coil 10 at the upper end 10a of the voice coil 10. Typical cone materials are paper, PMI (closed cell polymethacrylimide available from Evonik, HCL (HoneyCombLaminate), pearl mica, thermalum, aluminum and titanium coated polypropylene, PBO fiber, and various fabrics such as Nomex, Kevlar and Mylar available from DuPont. When electrical signals from an amplifier (not shown) pass through the voice coil 10, it turns into an electromagnet. As the current in the voice coil 10 oscillates, its polarity reverses and the voice coil 10 is alternately attracted to and repealed by fixed poles of the first and second magnet systems 24, 26. The voice coil 10 thus moves up and down the long axis 40 of the speaker driver 1, pushing and pulling the cone 18, which pushes and pulls air, transforming the electrical signal into sound. FIG. 1B is a detail of the motor assembly 4 of FIG. 1 illustrating the pole orientation of the first and second magnet systems 24, 26.
(38) Referring now to FIG. 2, a speaker driver 1 having a frame 2 comprising six j-beams 6 is illustrated. The j-beams, as depicted in FIG. 6E, may have a an upper end 6a, a lower end 6b, a shank area 7, a recess 7n within the j-beam inner periphery 7d, and a hook area 36. The lower end 6b of the j-beam 6 has a base 34 illustrated by the flattened area. Referring again to FIG. 2, the frame 2 may be assembled using at least four rings, an upper ring 3, a lower ring 22, an outer ring 20 and an inner ring 21. The j-beams 6 are aligned with the long axis and radially spaced apart from one another. Preferably, the j-beams are arranged equidistant from each other as seen in FIGS. 2-3 and 7. The spaced apart j-beams form large air gaps 35 in the frame 2 clearly depicted in FIGS. 2 and 7. The four rings may be attached to the j-beams 6 using means known in the art, e.g., fasteners, adhesive, welding and the like. FIG. 2 illustrates use of fasteners for rings 3, 20 and 21 left of the long axis 40 and adhesive on the right side of the long axis 40. Use of welding is not shown. FIG. 6c illustrates an upper ring 3 adapted for mounting six j-beams in a hexagonal arrangement. The perimeter of the outer edge 3b of the upper ring 3 may be shaped as desired for mounting the speaker driver 1 into a speaker cabinet (not shown) using fasteners through optional openings 3f.
(39) The lower ring 22 may be used to secure the lower ends of the j-beams 6b as seen in FIG. 2. The hook areas 36 of the j-beam 6 may be preferably arranged interiorly from the outer edge (3b) and the inner edge (3a) of the upper ring 3 of the j-beam 6 before inserting the outer edge 22b of the lower ring 22 into the shank recess 7n. The lower ring 22 may be preferably attached by adhesive within the shank recess 7n for extra stability. The inner edge 22a edge of the lower ring 22 may be adapted for attaching the outer circumferential edge of the lower surround 16b, preferably using adhesive. The inner edge 22a of the lower ring 22 may protrude interiorly from the shank section 7 or the length of the inner ring 22 may be less than the length of the shank recess 7n to facilitate adhering the outer circumferential edge 16b of the lower suspension 16 to the inner edge 22a of the inner ring 22.
(40) As illustrated in FIG. 2, the outer ring 20 may be used to attach the first magnet system 24. The first magnet system 24 may be preferably attached to the inner edge 20a of the outer ring 20. FIG. 6A is a cross-area view of the outer ring 20. The outer ring 20 may be annular shaped or may be a hoop and spoke design as illustrated. The outer edge of the hoop area 20b may be attached to the inner periphery 7d of the shank area 7 by adhesive or using fasteners. In an embodiment using a hoop and spoke design, the outer edge 20b of the optional spoke area 20c may be attached to the inner periphery 7d of the shank area 7 by adhesive as illustrated on the right side of the long axis 40 in FIG. 2 or using fasteners as illustrated on the left side of the long axis 40 in FIG. 2. The optional spoke area may be used as a standoff plate for positioning the first magnet system along the radial axis 39. The outer ring 20 may be attached to the inner periphery 7d of the shank area 7 substantially midway between the upper ring 3 and the lower ring 22 along the long axis 40.
(41) The inner ring 21 may be used to attach the second magnet system 26. The second magnet system 26 may be preferably attached to the outer edge 21b of the inner ring 21. The inner ring 21 may be mounted on the upper edge 36a of the hook area 36 of the j-beam 6. The inner ring 21 may be attached using adhesive or may be attached using fasteners as illustrated on the right and left side of the long axis 40 in FIG. 2.
(42) Continuing with FIG. 2, the cone 18 may be adhered to the voice coil 10 at the upper end 12a of the former 12 on the inner periphery 12c of the former 12. An embodiment illustrated in FIG. 2 has a suspension system of two half roll surrounds supporting the upper end 10a and lower end 10b of the voice coil 10 by adhesion to the outer periphery 12d of the former 12 of the voice coil 10 at the upper end 12a of the former 12 and by adhesion to the outer periphery 12d of the former 12 of the voice coil 10 at the lower end 12b of the former 12. The upper suspension 14 depicted in FIG. 2 is a half roll. In this embodiment, the outer edge 14b of the upper suspension 14 may be adhered to the inner edge 3a of the upper ring 3 above the motor assembly 4. The inner edge 14a of the upper suspension 14 may be adhered to the upper end 12a of the former 12 of the voice coil 10 along the outer periphery 12d of the former 12 of the voice coil 10. The outer edge 16b of the lower suspension 16 may be adhered to the inner edge 22a of the lower ring 22 below the motor assembly 4. The inner edge 16a of the lower suspension 16 may be adhered to the lower end 10b of the voice coil 10 along the outer periphery 12d of the former 12 of the voice coil 10 at the lower end 12b of the former 12 of the voice coil 10. Thus, in aspects, the voice coil 10 of this embodiment may be supported by adhesion of at least two suspension members, at least one on its upper end 10a and at least one on its lower end 10b. In some embodiments upper and lower suspension members of may be of dissimilar shape (not shown). FIG. 2 illustrates an upper suspension 14 having a half roll substantially similar to the lower suspension 16. Preferably, the upper and lower suspension members 14, 16 are adhered to oppose each. More preferably, the upper suspension 14 and the lower suspension 16 are symmetrically opposed about their long and radial axes, like a mirror as illustrated in FIG. 2, with the upper suspension member crown 14c facing upward and the lower suspension member crown facing 16c downward.
(43) The lengths of the magnet gap L.sub.1, the winding L.sub.2, the former L.sub.3 and the speaker driver L.sub.4 are illustrated in FIG. 2. The voice coil 10 of this illustrated embodiment is overhung, having a winding length L.sub.2 longer than the magnetic gap length L.sub.1. Although the speaker driver 1 of this disclosure may use an underhung voice coil 10, wherein the winding length L.sub.2 is shorter than the magnetic gap length L.sub.1 or an evenhung voice coil wherein the winding length L.sub.1 is substantially equal to 100 percent of the magnet gap length L.sub.1 using an overhung voice coil 10 may be preferred. The winding length L.sub.2 may be at least twenty percent the length of the former L.sub.3 and may be from about thirty percent to about eighty percent of the length of the speaker driver L.sub.4. The winding length L.sub.2 may be preferably configured to have the same amount of winding within the magnetic gap 5 corresponding to the maximum designed excursion of the cone 18.
(44) FIG. 3 is a cross-sectional top view of the speaker driver 1 embodiment in FIG. 2 taken along the section line 3-3. FIG. 3 illustrates the radial symmetry of the speaker driver 1. Reviewing the elements from the outermost to the innermost, one may see the j-beam 6; the outer edge 20b of the outer ring 20, the outer ring 20 (including the spoke area 20c and the hoop area 20e), the inner edge 20a of the outer ring 20; the outer edge 24b of the first magnet system 24, the first magnet system 24, the inner edge 24a of the first magnet system 24; an outer portion of the bisected magnetic gap 5b; the voice coil 10 (including the winding 11 and the former 12); the inner portion of the bisected magnetic gap 5a; the outer edge 26b of the second magnet system 26, the second magnet system 26, the inner edge 26a of the second magnet system 26, the outer edge 21b of the inner ring 21, the inner ring 21 and the inner edge 21a of the inner ring 21. FIG. 3A is an expanded view of the magnetic gap 5, substantially bisected by the voice coil 10 comprising the winding 11 and former 12 into magnetic gap portions 5a and 5b.
(45) As shown in FIG. 4, one embodiment of a motor assembly 4 comprises a first magnet system 24 and a second magnet system 26. The second magnet system 26 may be concentrically aligned along radial axis 39 inside the first magnet system 24 such that the outer diameter of the second magnet system D26b is smaller than the inner diameter of the first magnet system D24a. Each magnet system may be made from a plurality of radially polarized arc magnets 28 fixed in an annular ring. The plurality of arc magnets 28 forming the first magnet system 24 may be attached to the inner edge 20a of the outer ring 20 (See FIG. 2.) or they may be attached to each other to form an annular ring before attachment to the inner edge 20a of the outer ring 20. Similarly, the plurality of arc magnets 28 forming the second magnet system 26 may be attached to the outer edge 21b of the inner ring 21 to form an annular ring or they may be attached to each other to form an annular ring before attachment to the outer edge of the inner ring 21b. The first magnet system 24 or the second magnet system 26 may be encapsulated in epoxy. The first and second magnet systems 24, 26 may preferably be aligned along the long axis 40. (See FIG. 2.)
(46) Continuing with FIG. 4A depicts the magnetic pole arrangement for two of the plurality of arc magnets 28. In this embodiment, the poles are aligned such that a southern pole may be at the outer edge 24b of the first magnet system 24, a northern pole may be at the inner edge 24a of the first magnet system 24, a southern pole may be at the outer edge 26b of the second magnet system 26 and a northern pole may be located at the inner edge 26a of the second magnet system 26. In another embodiment, the poles may be reversed for each magnet system. The lines of magnetic flux coupling the two magnet systems are shown in FIG. 4A flowing symmetrically across the magnetic gap 5. A preferred embodiment of the motor assembly illustrated in FIG. 4, may be symmetrically aligned about both its long and radial axes.
(47) FIG. 5 is a cross-section view of one embodiment of a voice coil support system 9 of this disclosure. The voice coil support system 9 comprises the voice coil 10 and opposing upper and lower suspension members 14, 16, which may have a mirror like image with opposing symmetrical shapes about the radial axis 39. The outer edge 14b of the upper suspension 14 may be configured for adhesion to a speaker driver frame (not shown), preferably above a motor assembly (not shown). The inner edge 14a of the upper suspension 14 may be adhered to the outer periphery 12d of the former 12 at the upper end 12a of the former 12. The outer edge 16b of the lower suspension 16 may be configured for adhesion to a speaker driver frame (not shown), preferably below a motor assembly (not shown). The inner edge 16a of the lower suspension 16 may be adhered to the outer periphery 12d of the former 12 at the lower end 12b of the former 12. Thus, the voice coil 10, which comprises a winding 11 and a former 12, may be supported on its upper and lower ends 10a, 10b by the upper and lower suspension members 14, 16. The voice coil 10 may optionally have a collar (not shown). For voice coils without collars, the ends of the former 12a, 12b and ends of the voice coil 10a, 10b are coincident. The voice coil support system 9 illustrated in FIG. 5, is substantially symmetrical about its long axis 40 and radial axis 39. The length of the winding L.sub.2 may be at least twenty percent of the length of the former L.sub.3 Preferably the length of the winding L.sub.2, may be from about twenty percent to about 90 percent of the length of the former L.sub.3. The cone 18, shown in phantom, may be adhered to voice coil support system 9 at the inner periphery 12c of the former 12 at the upper end 12a of the former 12 along the circumferential edge 18a of the cone 18. Thus, the cone is supported only by the voice coil support system. In the illustrated embodiment, the diameter of the voice coil D10 is larger than the diameter of the cone D18. The upper suspension member crown 14c faces upward and the lower suspension member crown 16c faces downward.
(48) FIG. 6A is a cross-sectional top view of an outer ring 20 for use in a frame embodiment of this disclosure. The outer ring 20 illustrated is a preferable hoop and spoke configuration. The outer perimeter of the hoop and spoke 20c may form an outer edge 20b of the outer ring 20 that may have optional opening 20f (not shown) for fasteners which may be used to attach the outer ring 20 to the shank area 7 of the j-beams 6 of the frame 2 as seen in FIG. 2 to the left of the long axis 40 or the outer ring 20 may be attached to the frame 2 with an adhesive as seen to the right of the long axis 40 in FIG. 2. The outer ring 20 as illustrated with a hoop 20e may have an inner perimeter forming an inner edge 20a of the outer ring 20. A first magnet system 24 (not shown) may be attached to the inner edge 20a of the outer ring 20.
(49) FIG. 6B is a cross-sectional top view of an inner ring 21 for use in a frame embodiment of this disclosure. A second magnet system 26 (not shown) may be attached to the outer edge 21b of the inner ring 21. The inner edge 21a of the inner ring 21, may have optional openings 21f for use with fasteners (not shown) to attach the inner ring 21 to a hook area 36 of the j-beams 6 of the frame 2 (not shown). Alternatively, the inner ring may be adhered to a frame (not shown).
(50) FIG. 6C is a cross-sectional top view of an upper ring 3 for use in a frame embodiment of this disclosure. The upper ring 3 may be adapted for mounting a speaker driver (not shown) to a speaker cabinet (not shown) through the optional opening 3f in the ring 3. The upper ring 3 may be integrally formed with a frame (not shown), opening 30f, illustrated in FIG. 6C, may be provided in the upper ring 3 which aligns with opening 7f in the shank area 7 of the j-beam 6 use with fasteners (not shown) to attach the upper ring 3 to a j-beam 6 of a frame 2 (not shown). The openings 30f may be in a polygonal arrangement, for example a hexagon, as seen in FIG. 6C. The inner edge 3a of upper ring 3 may be adapted to provide a surface for adhesion of the outer edge 14b of the upper suspension 14 (not shown).
(51) FIG. 6D is a cross-sectional top view of a lower ring 22 for use with a frame embodiment of this disclosure. The outer edge 22b of the lower ring 22 may be inserted in a recess 7n at the lower end 6b of a j-beam 6 (See FIG. 6E.) to facilitate arrangement of the j-beams 6 and provide frame rigidity. The inner edge 22a of the lower ring 22 may provide a surface for adhesion of the outer edge 16b of the lower suspension 16 (not shown).
(52) FIG. 6E is a cross-sectional side view of a j-beam 6 for use with a frame embodiment of this disclosure. The j-beam 6 may have a shank area 7 and hook area 36. The j-beam 6 may also have an upper edge 36a atop the hook area 36 and an upper edge 7a atop the shank area 7. A recess 7n may be formed within the inner periphery 7d of the shank area 7 of the j-beam 6 for insertion of the lower ring (See also FIG. 6D). The lower end 6b of the j-beam 6 has a base 34 illustrated by the flattened area. The j-beam 6 may have optional openings 7f, 36f for fasteners.
(53) FIG. 6F is a top view of an assembled frame 2 embodiment of this disclosure using six j-beams 6. The j-beams 6 may be held substantially equidistant by the upper ring 3 and the lower ring 22 (shown in phantom) with the hook area 36 of each j-beam 6 arranged inwardly from the outer edge 3b and the inner edge 3a of the upper ring 3. The shank area 7 of the j-beam 6 is shown in phantom. Optional fastener openings 30f and 7f and 21f and 36f may be provided for attaching the upper edge 7a of shank area 7 of the j-beam 6 to the upper ring 3 and the upper edge 36a of the hook area 36 of the j-beam 6 to the inner ring 21, respectively. Also illustrated is an opening 3f in the upper ring 3 for fasteners to mount the speaker driver to a speaker cabinet (not shown).
(54) FIG. 7 The speaker driver frame 2 comprising three j-beams 6, a motor assembly 4 and a magnetic gap 5 are illustrated. The j-beams 6, as depicted in FIG. 6E, may have an upper end 6a, a lower end 6b, a shank area 7, a recess 7n within the inner periphery 7d of the shank area 7, and a hook area 36. The lower end 6b of the j-beam 6 may have a base 34 illustrated by the flattened area. As shown in FIG. 7, the frame 2 may be assembled using an upper ring 3, a lower ring 22, an outer ring 20 and an inner ring 21. The j-beams 6 are preferably arranged equidistant from each other along a radial axis 39. The upper ring 3 in FIG. 7 may be attached to the j-beams 6 using means known in the art. Openings 30f and 7f, 20f, and 21f and 36f may be provided for fasteners for attaching the upper ring 3 to the shank area 7 of the j-beam 6, the outer ring 20 to the shank area 7 of the j-beam 6 and the inner ring 21 to the hook area 36 of the j-beam 6, respectively. An opening 3f may be provided in the upper ring 3 to mount the speaker driver to a speaker cabinet (not shown). The outer ring 20 may be used to attach the first magnet system 24 along the inner edge 20a of the outer ring 20. The inner ring 21 may be used to attach the second magnet system 26 along the outer edge 21b of the inner ring 21. The magnetic gap 5 is formed between the first and second magnet systems 24, 26.
(55) FIG. 9 is a front view of an alternate embodiment of the speaker driver 201 having j-beams 206, which merge at the base 234 to form shared hook areas 236. In this alternate embodiment, the symmetrical motor assembly (hidden by the outer ring), symmetrical voice coil support system, voice coil 210 and open coil frame design are similar to the components in FIG. 2. The alternate embodiment illustrates eight j-beams 206 (the back four being hidden from view by the front four), which merge at the base 234 to form four shared hook areas 236. In this embodiment, two j-beams 206 share a single hook area 236. Although the ratio of j-beam shanks 207 to shared hook areas 236 is typically two to one, other ratios may be used. The j-beams 206 may have an upper end 206a, a lower end 206b, a shank area 207, a recess 207n within the j-beam 206 inner periphery 207d and a shared hook area 236. The lower end 206b of the j-beam 206 has a base 234. The frame 202 may be assembled using at least four rings, an upper ring 203, a lower ring 222, an outer ring 220 and an inner ring 221 (hidden in this view by outer ring 220). The j-beams 206 of this embodiment are generally aligned with the long axis 240 and radially spaced apart from one another, excepting shared hook areas 236, arranged interiorly, which are integrally formed with the inner ring 221. (FIG. 10) The j-beams 206 form large interconnected air gaps 235 in the frame 202, unlike prior art drivers with cylindrical walls encircling the voice coil 210, which trap and absorb heat.
(56) FIG. 9 also illustrates use of two suspension members 214, 216. These suspension members are known to those in the art as half roll surrounds. The two suspension members 214, 216 are arranged such that the crown the upper suspension member 214c is arranged in an opposing manner to the crown of the lower suspension member 216c like mirror images about the radial axis 239. The upper 214 and lower suspension members 216 may be respectively adhered between the voice coil 210 at the upper and lower ends 210a, 210b of the voice coil 210 and frame 202 on opposite sides of the motor assembly 204 (not shown). The two suspension members 214, 216 are preferably arranged to be symmetrical about both the long and radial axes of the speaker driver 201. The two suspension members 214, 216 support the voice coil 210 and the cone 218 (not shown), without use of any additional suspension members. Large interconnected air gaps 235 defined by the j-beams 206 are illustrated throughout the frame 202.
(57) FIG. 10 is a perspective view of a preferred embodiment of an open coil frame 202; which, excepting the outer ring 220, is integrally formed. In this embodiment, the j-beams 206 merge at the base 234 to form shared hook areas 236. An upper ring 203, inner ring 221 and lower ring 222 integrally formed with the j-beams 206 are illustrated in FIG. 10. The shank areas 207 of the j-beam may have cross-members 223 with through holes 223f between j-beams 206 having shared hook areas 236 for aligning and fastening the outer ring 220 to the frame 202. FIG. 10A is a bottom view of this preferred embodiment illustrating the merging of two j-beam lower ends 206b at the base 234 into a shared hook area 236. In an alternate embodiment, the inner ring 221 and the outer ring 220 are separate from the frame 202 as seen in FIG. 12B. FIG. 10B is a top view of outer ring 220 depicting four spokes, used as standoff plates 220c, extending radially outward from the outer ring outer edge 220b. Each standoff plate 220c may have openings 220f provided for receiving fasteners for attaching the outer ring 220 to the shank area cross-member 223 of the j-beam 206. The standoff plates 220c are used to position the first magnet system.
(58) FIG. 11 is a perspective view of an alternate embodiment of a frame 302. This embodiment also illustrates an upper ring 303, inner ring 321 and lower ring 322 integrally formed with the j-beams 306. The j-beams 306 may have an upper end 306a, a lower end 306b, a shank area 307, a recess 307n within the inner periphery of the shank area 307d near the lower end of the j-beam 306b before the bend of the j-beam, a hook area 336 and a base 334. In this embodiment, the bases of the j-hooks 334 are integrally formed with a base ring 334a. The shank areas 306 of this embodiment are generally aligned with the long axis 340 (not shown). The j-beams 206 are radially spaced apart from one another with the hook area 336 arranged interiorly and integrally formed with the inner ring 321 disposed on the upper end of the hook area 336a. The j-beams 306 form large interconnected air gaps 335 in the frame 302.
(59) FIG. 12A is a partial perspective view of an alternate embodiment of a speaker driver 301, having the frame 302 of FIG. 11, which illustrates the open voice coil frame design. The speaker driver 301 includes a frame 302; a motor assembly 304; a voice coil 310, an upper suspension 314, a lower suspension 316 and a cone 318. The concentrically disposed voice coil 310 is typically made by winding wire around a bobbin, known as the winding 311 and former 312, respectively. FIG. 12 illustrates an embodiment using an overhung voice coil. The motor assembly 304 comprises two annular magnet systems 324, 326 concentrically disposed within the frame 302 about radial axis 339. The voice coil 310 is shown substantially bisecting a magnetic gap 305 formed between the two magnet systems 324, 326.
(60) FIG. 12A also illustrates use of two suspension members 314, 316 wherein the upper suspension member 314 and the lower suspension member 316 have corrugated or sinusoidal shapes. These suspension members are known to those in the art as spiders. The two suspension members 314, 316 are arranged such that the crowns of successive arches of the upper suspension members are arranged in an opposing manner to the lower suspension member like mirror images about the radial axis 339. The upper 314 and lower suspension members 316 may be respectively adhered between the voice coil 310 at the upper and lower ends 310a, 310b of the voice coil 310 and frame 302 on opposite sides of the motor assembly 304. The two spiders illustrated are arranged to be symmetrical about both the long and radial axes of the speaker driver 301. The two suspension members 314, 316 support the voice coil 310 and the cone 318, without use of any additional suspension members.
(61) The motor assembly 304 illustrated in FIG. 12B comprises two permanent annular ring magnets systems 324, 326. The first magnet system 324 may be disposed outside the second magnet system 326. As illustrated in FIG. 12B, each magnet system 324, 326 may be made from a plurality of arc magnets 28. The plurality of arc magnets 28 forming the first magnet system 324 may be attached to the inner edge 320a of the outer ring 320. Similarly, the plurality of arc magnets 28 forming the second magnet system 236 may be attached to the outer edge 321b of the inner ring 321 to form an annular ring or the arc magnets 28 may be attached to each other to form an annular ring before attachment to the outer edge of the inner ring 321b. In an alternate embodiment, the plurality of arc magnets 28 may be attached to each other to form an annular ring before attachment to the inner edge 320a of the outer ring 320 and before attachment to the outer edge of the inner ring 321b.
(62) An embodiment of the motor assembly 304 illustrated in FIGS. 12B and 12C3 is physically and magnetically symmetrical about the long axis 340 and radial axis 339. FIG. 12C illustrates a magnetic gap 305 formed between the first and second magnet systems 324, 326, which is bisected by voice coil 310. The length of the first and second magnet systems 324, 326 illustrated have the same length L1 as the outer and inner rings 320, 321 and the magnetic gap 305. In preferable embodiments illustrated in FIGS. 12B and 12C, the plurality of magnets 28 on both sides of magnetic gap 305 have the same composition and same magnetic strength. Another aspect of this preferable embodiment is for the outer and inner rings 320, 321 to be made of non-ferromagnetic material. Use of these materials combined with the geometry illustrated in FIGS. 12B and 12C form a substantially symmetrical magnetic motor assembly. FIG. 12C also illustrates an embodiment of an overhung voice coil 310 wherein the amount of winding 311 above and below the motor assembly 304 about the radial axis (not shown) of the driver 301 is substantially equal. The radial polarities of the first and second magnet systems 324, 326 are illustrated in FIG. 12C wherein the north pole of the first magnet system 324 faces the voice coil 310 and the south pole of the second magnet system 326 faces the voice coil 310. In an alternate embodiment, the polarities may be reversed.
(63) Turning back to FIG. 12B, the outer ring 320 may be used to attach the first magnet system 324. The first magnet system outer edge 324b may be preferably attached to the inner edge 320a of the outer ring 320. The outer ring 320 may be annular shaped, but preferably has a hoop and spoke design. The outer edge of the spoke area 320c of the outer ring 320, which may be used as a standoff plate, may be attached to the inner periphery 307d of the shank area 307 by adhesive or fasteners as illustrated on the right side of FIG. 12A. The second magnet system inner edge 326a may be attached to the inner ring outer edge 321b attached using adhesive or attached using fasteners. The outer ring 320 and inner ring 231 may be concentrically arranged substantially midway between the upper ring 303 and the lower ring 322 in an embodiment of the speaker driver.
(64) Turning to FIG. 13, the plurality of arc magnets 28 are shown in perspective view. The arc magnets 28 may be held together magnetically preferably using shoulder portions 28a. The length of the shoulder L28 being from about 10% to about 15% the length of the arc magnet L28. Optionally, the arc magnet shoulders 28a may have protruding areas 28b that fit into recessed area 28c for interlocking the plurality of arc magnets. The arc magnets preferably have ten degrees of arc.
(65) FIG. 14A illustrates a half roll suspension member 114. FIG. 14B illustrates a half roll suspension member bisected into two segments 114a and 114b. The inner diameter D114a of segment 114a is smaller than the outer diameter D114b of segment 114b. Because of the difference in diameters, the amount of material being pushed and pulled by the cone differs between the inner 114a and outer 114b segments of the suspension member 114. This structural difference between the segments is thought to be a contributing reason for non-symmetrical response of suspension members, as the suspension member changes position relative to voice coil position as it moves through downward and upward excursions.
(66) The foregoing description is directed to particular embodiments of the present disclosure for the purpose of illustration and explanation. It will be apparent, however, to one skilled in the art that many modifications and changes to the embodiment set forth above are possible without departing from the scope of the disclosure.
