WO2002058433A1

WO2002058433A1 - Speaker surround structure for maximizing cone diameter

Info

Publication number: WO2002058433A1
Application number: PCT/US2002/001648
Authority: WO
Inventors: Ronnie S. Espiritu
Original assignee: Harman International Industries, Inc.
Priority date: 2001-01-19
Filing date: 2002-01-18
Publication date: 2002-07-25
Also published as: KR100902203B1; KR20080081371A; EP1364556A4; JP2008113469A; JP4926992B2; EP2317775B1; MXPA03006443A; CN101291548A; CN101291548B; JP2012039647A; WO2002058433A8; CN1496662A; JP2004521538A; KR20030066822A; EP1364556A1; EP2317775A1; EP1364556B1

Abstract

In a compact speaker, to enable the deployment of a diaphragm (14) of larger diameter than is used conventionally for the corresponding basket (10) size, the outer basket-attachment portion of the surround-suspension (12) is made in a special configuration shaped as an axial skirt (16a), i.e. generally tubular in the case of a round speaker basket, instead of the planar shape of the basket-attachment portion of conventionally speakers. The speaker basket (10) of the present invention is made with a corresponding axial peripheral flange of which the inner wall made to serve as a landing (20) for adhesive attachment to the outer wall of the axial surround suspension flange. This special configuration retains the required resilience and capability of full excursion while enabling enlargement of the effective vibrating piston area substantially by deployment of a larger cone. The basket may be of the type that is stamped from metal, e.g. as in popular conventional speakers, or in other embodiments it may be cast from metal or molded from suitable plastic material. The outer attachment member of this surround-suspension is preferably configured in a special cross-sectional shape that maximizes the area available for adhesive attachment to the basket.

Description

PATENT APPLICATION for SPEAKER SURROUND STRUCTURE FOR MAXIMIZING CONE DIAMETER

FIELD OF THE INVENTION The present invention relates to the field of audio loudspeakers/transducers and more particularly to improvement of midrange and low frequency response of full range speakers of popular compact size categories.

BACKGROUND OF THE INVENTION

Compact speakers are categorized by outer dimensions, e.g. the diameter of a round speaker, while their main performance limitation, i.e. midrange and low frequency performance, is determined mainly by diaphragm area and excursion capability, i.e. the volume of air moved by the effective moving portion of the diaphragm acting as a piston.

Large quantities of small-sized speakers are used in vehicles such as cars, trucks, boats, aircraft, etc. Such speakers are generally designed to mechanically fit a particular mounting pattern used by vehicle manufacturers, typically including a main cutout and surrounding mounting holes, dimensioned according to standards originating from different world regions. Replacement speakers are generally required to fit the mounting pattern and space originally provided in the vehicle.

Round speakers having basket diameter in the 4"-7" size range are in extremely high quantity vehicular usage in the U.S. and throughout the world. Most of these in the 6"-7" range are made to either a JIS Japanese standard that specifies 6.18 inches (157mm) diameter or a DIN German standard used in Europe that specifies 6.69 inches (170mm) diameter. A useful factor of merit regarding size efficiency is obtained by comparing the cone area to the total projected basket area. This ratio factor is tabulated along with typical basket diameters and associated cone diameters as follows:

TABLE 1 KEY DIMENSIONS IN POPULAR COMPACT SPEAKERS Nominal Size Version Cone diam. Basket Cone area/Basket area mm Diam. mm

4 inch 73 102.3 0.51

5 ^l inch 92 129 0.51

6 V inch JIS Japan (a) 111.8 157 0.51

(b) 115.3 157 0.54

DIN Europe 119.3 170 0.49

TABLE 1 shows that conventional speaker structure provides typically a ratio of cone basket area = 0.51. The (b) version of the JIS type represents an effort to upgrade part way toward the DIN cone size and corresponding midrange and low frequency performance capability while retaining the smaller JIS basket size.

Since all practical loudspeakers are subject to an inherent dropout of acoustic efficiency at a low-end cutoff frequency in inverse proportion to the cone area (for a given cone excursion), clearly for a full range speaker of any size, it is very beneficial to increase the cone diameter since each percent that the cone diameter can be increased yields more than double the percent increase in cone area. Accomplishing increased cone area without increasing the outer dimensions of the speaker basket, whether it is round, oval or other shape, is particularly beneficial to midrange and low frequency performance of compact speakers that are subject to strict constraints on basket size, e.g. as used in large quantities in vehicular sound systems as well as in small personal radio/stereo players, multi-media computer systems, etc..

DISCUSSION OF RELATED KNOWN ART

FIG. 1 is a cross-section taken at an edge portion of a formed sheet-metal basket 10 of a typical loudspeaker of known art. A typical surround-suspension 12 has as its outwardly-extending peripheral portion a radial planar outer flange 12A by for adhesive attachment to a planar margin landing 10A in the peripheral region of basket 10, and has as its inwardly-extending peripheral portion a conical inner flange 12B for adhesive attachment to the cone 14, shown in part. The central arched flexible portion 12C of the annular surround suspension member 12 constrains cone 14 radially but allows it to vibrate in an axial direction when driven by the voice coil.

The position of the cone 14 and its surround-suspension 12 are shown in solid lines for the normal "at rest" condition. The displaced position of surround 12' and cone 14' is shown in dashed lines for a maximum driven condition at maximum downward cone excursion. Displacement of the arched portion 12C of the surround-suspension 12 provides an effective piston diameter that is somewhat larger than the cone diameter extending to a mid-region of the arched portion 12C.

FIG. 1 A is a cross-section of a basket 10A which, as an alternative to pressed sheet metal construction, is molded from plastic or cast from metal such as aluminum, and configured to form a landing as shown, equivalent to that of a pressed sheet metal basket as in FIG. 1, for adhesive attachment of the outer flange 12A of the surround-suspension 12.

U.S. patents 5,111,510 to Mitobe and 5,115,474 to Tsuchiya et al show cross- sectional drawings that represent typical conventional speaker surround-suspension structure. Their standard cone mounting configuration features an outwardly extending radial planar fastening flange on the surround-suspension, as shown in FIGs. 1 and 1 A and as practiced universally in the great majority of speakers of known art.

U.S. patent 5,867,583 to inventors Hazelwood, Espiritu and Jorgensen for TWIST- LOCK MOUNTABLE VERSATILE LOUDSPEAKER MOUNT discloses non- conventional mounting systems including special surround-suspension configurations that yield increased cone basket diameter ratio; e.g. enabling a DIN cone to be utilized in a JIS basket accomplished a one/basket area ratio of 0.58, i.e. more than 13% increase over that of conventional speakers (typically 0.51; refer to TABLE 1 above).

OBJECTS OF THE INVENTION

It is a primary object of the present invention to provide non-conventional mountings for the surround-suspension of round cone-type loudspeakers that enable the use of larger-than-conventional cone sizes and thus provide increased cone/basket diameter, and accordingly enhance the midrange and low frequency performance.

It is a further object to provide novel configuration and mounting systems wherein the surround-suspensions are configured in a manner to enable a larger cone diameter by occupying less space in the outer fastening region and yet provide at least equal the cone excursion capability available in a comparable conventional speaker.

It is a further object to provide embodiments that utilize standard speaker baskets of the formed sheet metal type as well as baskets that are molded from plastic or cast from metal such as aluminum.

It is a further object, in the special surround-suspension attachment configurations of the invention to provide a high quality level of adhesive attachment performance and reliability, e.g. through maximizing the interface area of adhesive attachment. SUMMARY OF THE INVENTION

The above mentioned objects have been accomplished by the subject speaker of the present invention by utilizing a diaphragm of larger diameter than is used conventionally for the corresponding basket size, and by making the outer peripheral portion of the surround- suspension in a special configuration that retains the required resilience and capability of full excursion while enlarging the effective piston area substantially by deploying a larger diameter cone and/or increasing the width the flexible arched portion of the surround- suspension and thus increasing the effective vibrating area thereof.

Instead of the conventional planar shape of the surround-suspension outer attachment member extending radially outward from the flexible arched portion, in the novel departure of the present invention, the outer attachment member of the surround- suspension is made in the form of an axial skirt, i.e. generally tubular in the case of a round speaker basket, extending rearwardly and dimensioned to fit closely inside a corresponding axial flange provided on the periphery of the basket, extending forwardly, with adhesive fastening in the interfacing region.

< The axial skirt may be specially shaped to maximize the adhesive fastening area.

For various embodiments and versions, the basket may be of the type that is stamped from metal, similar to the conventional JIS speakers, or it may be of the type that is cast from metal or molded from suitable plastic material.

BRIEF DESCRIPTION OF THE DRAWINGS The above and further objects, features and advantages of the present invention will be more fully understood from the following description taken with the accompanying drawings in which: FIGs. 1-9 each show a cross-sectional view of a rim region of a speaker. FIG. 1 and FIG. 1 A depict typical conventional speakers, as discussed above under

Discussion of Known Art.

FIGs. 2-9 depict embodiments and versions of speaker cone suspension systems structured in accordance with the present invention.

FIG. 2 depicts a basic embodiment having the surround-suspension specially formed with an outer skirt, with its outer surface interfacing and adhesively attached to the inner surface of the flange at the basket rim.

FIG. 3 depicts surround attachment similar to FIG. 2 with the skirt fitted into an annular channel formed in a specially molded or cast basket.

FIG. 4 depicts surround attachment similar to FIG.2 with an added annular retaining ring.

FIG. 5 depicts a different version of the general configuration of FIG. 4 with the retaining ring shaped to provide an annular mounting channel.

FIG. 6 depicts a preferred embodiment with the surround specially shaped to provide a flared cross-sectional shape in the mounting region.

FIG. 7 depicts ah alternative embodiment with a doubled-back flange in the mounting region.

FIG. 8 depicts a version of the embodiment shown in FIG. 10 with increased interface area for enhanced adhesive fastening. FIG. 9 depicts an embodiment deploying an annular spacer that enables the speaker to be mounted onto the rear side of a panel.

DETAILED DESCRIPTION

FIGs. 1-9 each show a cross-sectional view of a basket rim region of a speaker.

FIGs. 1 and 1 A depict the surround-suspension mounting and attachment configurations of typical conventional speakers using formed sheet metal or molded cast baskets respectively, as discussed above under Discussion of Known Art.

FIGs. 2-9 depict different embodiment and versions of novel cone suspension surround mountings configured in accordance with the present invention.

FIG. 2 depicts a basic embodiment of the present invention. A specially configured surround-suspension 16 is made with its outer attachment member formed as an axial skirt 16A extending forwardly, constituting a basic departure from the conventional practice of attachment via a outwardly-extending radial-planar flange 12A of prior art shown in FIGs. 1 and 1A.

Skirt 16A interfaces the inner surface of the basket rim and its lower edge rests on the landing region. Skirt 16A is adhesively attached at interfacing surfaces as shown. This basic embodiment can be utilized with a pressed sheet metal basket 10 as shown, or with a basket that is molded from plastic or cast from metal such as aluminum.

The increased size of cone 14A, i.e. increased diameter in the case of a round speaker, made possible by the present invention, is evident in FIG. 2 in comparison with the conventional cone 14 in FIGs. 1 and 1A.

FIG. 3 depicts an embodiment that utilizes the specially shaped surround-suspension 16 as in FIG. 2; however, skirt 16A is fitted into an annular channel whose outer wall is formed by the inner wall of the basket rim 18 and whose inner wall is formed by a thickened region 18A of the basket 18, which is molded from plastic or cast from metal such as aluminum. This configuration provides superior attachment reliability due to increased adhesive area in the interface between the inner wall surface of the peripheral flange of basket 18 and the outer wall surface skirt 16A of surround-suspension 16.

FIG. 4 depicts a version of the basic embodiment of FIG. 2 wherein the surround- suspension 16 is the same as in FIGs 2 and 3, but it is retained on the inside by an annular retainer ring 20 shaped as shown and adhesively fastened to the landing in basket 10. The attachment skirt 16A of suspension member 16 is fastened in place adhesively to the rim of basket 10 and to the interface with ring 20.

FIG. 5 depicts a version of the general embodiment of FIG. 4 wherein the retainer ring 22 is configured with an annular channel that accepts the attachment skirt 16A of suspension member 16. The thickness of the outer wall of the channel in ring 22 should be taken into account in dimensioning the basket size, the cone size and/or the span of the flexible arched portion of suspension member 16.

FIG. 6 depicts a preferred embodiment of the present invention wherein the surround-suspension 24 is specially shaped to provide a flared cross-sectional shape, as shown, in the mounting landing region; this enables both the axial and radial interface regions to be fastened adhesively, so that high reliability is obtained by the increase in fastening area compared to that of the conventional fastening as in FIGs. 1, 1 A.

FIG. 7 depicts an alternative embodiment wherein the outer mounting skirt 26A of the surround-suspension 26 is doubled back itself as shown and adhesively fastened to the inner side of the peripheral flange of basket 10 as well to the planar margin landing.

FIG. 8 depicts an embodiment similar to that of FIG. 6 but with the mounting skirt 28 A of special surround-suspension 28 molded to form the shape shown which flares to a thickness that enables an enlarged additional area of adhesive fastening including substantially the entire area of the planar margin landing 20 of the basket 10. FIG. 9 depicts an embodiment of the invention that further includes a mounting adaptor 32, fitted inside the axial peripheral flange of basket 10, that enables the speaker to be mounted onto the rear side of a panel.

The skirt of surround-suspension member 30 is made with a narrow fastening flange 30A extending outwardly from the edge of the skirt and fastened adhesively to the margin landing of basket 10 and to a lower portion of an annular speaker mounting adaptor 32, which can be molded from plastic or formed/cast from metal. Adaptor 32 forms a spacer between the speaker and a panel interfacing the top horizontal surface of adaptor 32. Fastened adhesively to the inner surface of the rim of basket 10, the lower end of the vertical portion of adaptor 32 acting downwardly on the narrow fastening flange 30A provides additional interfacing area for enhancing the adhesive fastening.

In a 4" round speaker with a conventional basket having 129 mm outer diameter, incorporation of most embodiments of the present invention will enable the conventional cone diameter (92 mm) to be increased to 102.6 mm; an increase of 11.5% in diameter and 24.4% in area which provides significant improvement of low frequency response. With reference to TABLE 1, the cone area/basket area accomplished by the present invention in the 4" category is 0 633, compared to 0.51 for conventional speakers; an increase of 24% in this factor of merit of cone area/basket area.

In any of the embodiments, the arched portion of the surround-suspension may be made uniform in thickness or specially varied in thickness for increased compliance, e.g. shaped to be thinner in a central region and/or one or both flanges may be tapered.

The invention could be implemented in an alternative configuration wherein the surround-suspension skirt flange is disposed around the outside of the basket rim flange instead of the inside as shown, thus the inside axial, wall surface of suspension attachment skirt would interface and be adhesively attached to the outside axial wall surfaces of the basket rim flange.

Typically, in the different embodiments disclosed, the specially configured surround-suspension of the invention functions in co-operation with a conventional second cone suspension member, typically a concentric spider suspension deployed in a well known manner attached to a central voice coil region of the cone; however, the present invention can also be practiced in embodiments wherein the special surround-suspension functions as the sole cone suspension element.

Although shown herein for illustrative purposes as applied to round style basket speakers, the principle of the present invention, i.e. foreshortening, or eliminating the outwardly extending mounting flange of the surround-suspension, of the present invention is not limited to round style speakers: it may be practiced with speakers having basket of any practical shape including oval or rectangular.

This invention may be embodied and practiced in other specific forms without departing from the spirit and essential characteristics thereof. The present embodiments therefore are considered in all respects as illustrative and not restrictive. The scope of the invention is indicated by the appended claims rather than by the foregoing description. All variations, substitutions, and changes that come within the meaning and range of equivalency of the claims therefore are intended to be embraced therein.

Claims

What is claimed is:

1. A speaker cone-surround support system for maximizing effective piston area of a forwardly-facing cone constituting an acoustic diaphragm in a compact full-range speaker having a basket constituting a main speaker frame with an outer boundary, in a frontal plane perpendicular to a central axis of the speaker, encompassing a designated basket area, said cone surround system comprising: a surround-suspension, made and arranged to surround the cone and provide support thereto in a manner that allows vibration thereof for acoustic purposes, configured with a cross sectional shape, taken at a radial axis of the speaker, defining (a) a main flexible portion, made and arranged to allow functional vibration of the cone for acoustic purposes, extending between inner and outer suspension points located substantially in the frontal plane, (b) a cone-attachment flange extending from the inner suspension point, overlapping and adhesively attached to a peripheral suspension-attachment margin of the cone, and (c) an axial basket-attachment skirt extending rearwardly from the outer suspension point and configured overall to overlap and interface with a peripheral region of the basket, attachment means for securing the basket-attachment skirt of said surround- suspension to the peripheral region of basket; the cone being made to have an area in the frontal plane at the inner suspension point that is substantially greater than that of a cone of a comparable conventional speaker having a cone-suspension configured with a conventional planar radial basket-attachment flange, for a given basket area and a given span dimension of the main flexible portion of said surround-suspension measured between the inner and outer suspension points; and said surround suspension having an outer profile encompassing an area in the frontal plane that is at least 95% percent that of the basket.

2. The speaker cone-surround support system as defined in claim 1 wherein said attachment means comprises: a suspension-attachment flange of substantially uniform thickness, configured as part of the basket and extending axially from an outer extremity of a planar margin landing area disposed radially around a margin of the basket, extending in a forward direction to the frontal plane, having a predetermined shape and size to overlapping fit the basket- attachment skirt of said surround-suspension.

3. The speaker cone-surround support system as defined in claim 2 wherein the basket- attachment skirt of said surround-suspension is made to have a peripheral outer wall surface shaped and sized to fit closely into the inner wall of said suspension-attachment flange of the basket, adhesive material being applied in assembly in a manner to permanently attach the outer wall surface of the basket-attachment skirt of said surround-suspension member to the inner wall of said suspension-attachment flange of the basket.

4. The speaker cone-surround support system as defined in claim 3 wherein said basket-attachment skirt of said surround-suspension member is configured in a molding process to form a cross-sectional shape that flares to an increased edge thickness defining a flat basket-attachment surface substantially perpendicular to the outer surface of said basket-attachment skirt, made and arranged to interface a planar margin landing of said speaker basket, provided contiguous with the surround-attachment flange thereof and extending radially inwardly therefrom, said adhesive material being alto applied between the flat basket-attachment surface of the suspension-attachment flange and the planar margin landing of said speaker basket, so as to substantially increase a total interfacing area attached by adhesive.

5. The speaker cone-surround support system as defined in claim 3 wherein said attachment means comprises: a peripheral channel of substantially uniform width formed around said speaker basket, said channel having a first wall surface formed by the inner wall of said suspension- attachment flange of the basket and having a second and opposite wall surface spaced from the first wall surface by a substantially uniform width so as to provide a close fit of the basket-attachment skirt of said cone surround-suspension, inserted and retained in said channel in a mating manner, further secured in place by adhesive material applied in initial assembly in all interfacing areas therebetween.

6. The speaker cone-surround support system as defined in claim 5 further comprising: a built-up region forming a wall surface separated by a uniform distance from the inner surface of said suspension-attachment flange, thus providing the second wall surface of the channel; said speaker basket, including said suspension-attachment flange, being formed from plastic material in a molding process

7. The speaker cone-surround support system as defined in claim 5 further comprising: a wall member, attached to the planar margin landing of said basket separated by a uniform distance from the inner surface of said suspension-attachment flange, thus providing the second wall surface of the channel; said speaker basket, including said suspension-attachment flange, being formed from sheet metal in a stamping process.

8. The speaker cone-surround support system as defined in claim 7 wherein the molding member is further configured to have a cross-sectional shape characterized by a channel floor liner portion located so as to interface with the planar margin landing of said speaker basket, extending substantially to the inner wall of said suspension-attachment flange of the basket, the channel floor liner being adhesively attached to the planar margin landing of said basket and thus forming in said channel a floor lining made and arranged to interface and support an end region of the basket-attachment skirt of said surround- suspension member.

9. The speaker cone-surround support system as defined in claim 8 further comprising: a peripheral attachment liner made contiguous with the channel floor liner and arranged to interface between the planar margin landing of said basket and the outer wall of the basket-attachment skirt of said surround-suspension member.

10. The speaker cone-surround support system as defined in claim 2 wherein the cross- sectional shape of the basket-attachment skirt is characterized by a first portion thereof extending from the outer suspension point to the planar margin landing of the basket, at that point, folding back outwardly upon itself and extending substantially back to the outer suspension point while interfacing the inner wall of said suspension-attachment flange of the basket, being attached thereto adhesively, thus forming a two-layer outer attachment flange.

11. The speaker cone-surround support system as defined in claim 2 wherein said attachment means further comprises: a speaker mounting adaptor, for mounting onto a rear side of a panel, having a cross- sectional L shape characterized by an axial portion interfacing and attached to the inner wall surface of said suspension-attachment flange and extending substantially beyond the frontal plane to a corner junction with a radial portion that extends inwardly toward the central axis so as to form a panel-mounting flange; the basket-attachment skirt of said surround-suspension member being made and arranged to have a peripheral outer wall surface shaped and sized to fit closely into the inner wall of the axial portion of said speaker mounting adaptor, adhesive material being applied in assembly to a maximal available area so as to permanently attach the outer wall surface of the basket-attachment skirt of said surround-suspension member to the inner wall of the axial portion of said speaker mounting adaptor.

12. The speaker cone-surround support system as defined in claim 11 further comprising the basket-attachment skirt of said surround-suspension member being further configured with an end flange extending radially outwardly to the inner wall of said suspension- attachment flange thus forming a floor liner disposed between a rear edge of said speaker mounting adaptor and the planar margin landing of the basket.