# US 10,483,036 B2 · Voice coil having epoxy-bound winding layers > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,483,036 B2 - Document ID: US10483036B2 - Status: Granted - Kind: B2 - Application number: 15/260,112 - Filed: 2016-09-08 - Published: 2017-08-03 - Granted: 2019-11-19 - Earliest claimed: 2016-01-29 - Assignees: Apple Inc. - Applicants: Apple Inc. - Inventors: Alexander V. Salvatti - Web page: https://patentgrep.com/patent/US10483036B2 ## CPC - H01F 41/12: Insulating of windings ({impregnating or encapsulating of transformers H01F41/005} ; of conductors in general H01B13/06) - F02D 41/00: Electrical control of supply of combustible mixture or its constituents (F02D43/00 takes precedence {; control of engine starters F02N11/08, electrical control of engine ignition timing F02P5/145}) - H01F 5/06: Insulation of windings - H01F 7/064: {Circuit arrangements for actuating electromagnets (circuit arrangements for obtaining special operating characteristics H01F7/18; driving circuits for electromagnets making use of a switching regulator H01H47/325)} - H01F 7/1844: {Monitoring or fail-safe circuits (for relays H01H47/002)} - H01F 41/066: with insulation - H04R 9/045: {Mounting (H04R9/043 takes precedence)} - H04R 31/00: Apparatus or processes specially adapted for the manufacture of transducers or diaphragms therefor {(manufacture of microstructural arrangements of deformable or non-deformable structures in general B81C1/00182)} - H04R 9/06: Loudspeakers - H04R 2499/11: Transducers incorporated or for use in hand-held devices, e.g. mobile phones, PDA's, camera's - H01F: MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES - F02D: CONTROLLING COMBUSTION ENGINES (vehicle fittings, acting on a single sub-unit only, for automatically controlling vehicle speed B60K31/00; conjoint control of vehicle sub-units of different type or different function, road vehicle drive control systems for purposes other than the control of a single sub-unit B60W) - H04R: LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; ELECTRIC HEARING AIDS; PUBLIC ADDRESS SYSTEMS (producing sounds with frequency not determined by supply frequency G10K) ## Abstract An audio speaker including a bobbin-less voice coil having epoxy-bound winding layers is disclosed. More particularly, a voice coil may include a first winding layer and a second winding layer coaxially arranged about a central axis. The winding layers may include respective wire turns coiled about the central axis in a longitudinal direction. The winding layers may be bound by an epoxy matrix. For example, the epoxy matrix may be disposed radially between the first winding layer and the second winding layer to bond first wire turns to second wire turns, and to bond the winding layers to a speaker diaphragm. ## Claims ### Claim 1 A voice coil, comprising: a first winding layer including a plurality of first wire turns around a central axis, wherein the first wire turns are longitudinally disposed along the central axis between a first bottom turn and a first top turn; a second winding layer including a plurality of second wire turns coaxial with the first winding layer around the central axis, wherein the second wire turns are longitudinally disposed along the central axis between a second bottom turn and a second top turn, and wherein the first winding layer is radially offset from the second winding layer; and an epoxy matrix having a profile that includes an outer epoxy surface and an inner epoxy surface extending in a longitudinal direction relative to the central axis, wherein the epoxy matrix encapsulates the first winding layer and the second winding layer between the outer epoxy surface and the inner epoxy surface, and wherein the epoxy matrix bonds the plurality of first wire turns to the plurality of second wire turns to rigidify the voice coil, wherein the epoxy matrix includes an epoxy spacer longitudinally over one or more of the first top turn or the second top turn, and wherein the epoxy spacer has a height at least three times a diameter of a wire forming the wire turns. ### Claim 2 (depends on 1) The voice coil of claim 1, wherein the first top turn is longitudinally offset from the second top turn. ### Claim 3 (depends on 2) The voice coil of claim 2, wherein the epoxy spacer is radially offset from the first winding layer, and wherein the epoxy spacer is longitudinally over the second top turn. ### Claim 4 (depends on 1) The voice coil of claim 1, wherein the wire turns include the wire having a conductive core surrounded by an insulating jacket, and wherein the epoxy matrix contacts the insulating jacket of the wire of the first wire turns and the second wire turns. ### Claim 5 (depends on 4) The voice coil of claim 4, wherein the wire turns include respective turn diameters about the central axis, and wherein the turn diameters are less than 25 millimeters. ### Claim 6 (depends on 1) The voice coil of claim 1 further comprising a diaphragm configured to move along the central axis, wherein the voice coil is coupled to the diaphragm. ### Claim 7 (depends on 6) The voice coil of claim 6, wherein the epoxy matrix bonds the first top turn to the diaphragm. ### Claim 8 (depends on 1) The voice coil of claim 1, wherein the epoxy matrix encapsulates the first winding layer and the second winding layer by filling spaces between the first winding layer and the second winding layer. ### Claim 9 An electromagnetic transducer for sound generation, comprising: a diaphragm configured to move along a central axis; and a voice coil coupled to the diaphragm, wherein the voice coil includes: a first winding layer including a plurality of first wire turns around the central axis, wherein the first wire turns are longitudinally disposed along the central axis between a first bottom turn and a first top turn, a second winding layer including a plurality of second wire turns coaxial with the first winding layer around the central axis, wherein the first winding layer is radially offset from the second winding layer, wherein the second wire turns are longitudinally disposed along the central axis between a second bottom turn and a second top turn, and an epoxy matrix having a profile that includes an outer epoxy surface and an inner epoxy surface extending in a longitudinal direction relative to the central axis, wherein the epoxy matrix encapsulates the first winding layer and the second winding layer between the outer epoxy surface and the inner epoxy surface, wherein the epoxy matrix bonds the plurality of first wire turns to the plurality of second wire turns to rigidify the voice coil, wherein the epoxy matrix includes an epoxy spacer longitudinally over one or more of the first top turn or the second top turn, and wherein the epoxy spacer has a height at least three times a diameter of a wire forming the wire turns. ### Claim 10 (depends on 9) The electromagnetic transducer of claim 9, wherein the epoxy matrix bonds the first top turn to the diaphragm. ### Claim 11 (depends on 9) The electromagnetic transducer of claim 9, wherein the first top turn is longitudinally offset from the second top turn. ### Claim 12 (depends on 11) The electromagnetic transducer of claim 11, wherein the epoxy spacer is radially offset from the first winding layer, and wherein the epoxy spacer is longitudinally over the second top turn. ### Claim 13 (depends on 9) The electromagnetic transducer of claim 9, wherein the wire turns include the wire having a conductive core surrounded by an insulating jacket, and wherein the epoxy matrix contacts the insulating jacket of the wire of the first wire turns and the second wire turns. ### Claim 14 A method, comprising: winding a wire around a central axis to form a first winding layer and a second winding layer, wherein the first winding layer includes a plurality of first wire turns longitudinally disposed along the central axis between a first bottom turn and a first top turn, wherein the plurality of first wire turns are around the central axis, wherein the second winding layer includes a plurality of second wire turns coaxial with the first winding layer around the central axis, wherein the second wire turns are longitudinally disposed along the central axis between a second bottom turn and a second top turn, and wherein the first winding layer is radially offset from the second winding layer; placing an epoxy resin longitudinally over the first top turn and between the first winding layer and the second winding layer; curing the epoxy resin to form an epoxy matrix having a profile that includes an outer epoxy surface and an inner epoxy surface extending in a longitudinal direction relative to the central axis, wherein the epoxy matrix encapsulates the first winding layer and the second winding layer between the outer epoxy surface and the inner epoxy surface, wherein the epoxy matrix bonds the plurality of first wire turns to the plurality of second wire turns, wherein the epoxy matrix includes an epoxy spacer longitudinally over one or more of the first top turn or the second top turn, and wherein the epoxy spacer has a height at least three times a diameter of the wire forming the wire turns; and mounting the epoxy matrix on a diaphragm of an electromagnetic transducer, wherein the epoxy matrix couples the diaphragm to the first top turn. ### Claim 15 (depends on 14) The method of claim 14, wherein winding the wire includes winding the wire around a sleeve coaxially aligned with the central axis. ### Claim 16 (depends on 15) The method of claim 15 further comprising removing the sleeve from the winding layer. ### Claim 17 (depends on 16) The method of claim 16, wherein placing the epoxy resin includes filling a gap with the epoxy resin, wherein the gap is radially offset from the sleeve, and wherein the gap is longitudinally between the diaphragm and the first top turn. ### Claim 18 (depends on 14) The method of claim 14, wherein the epoxy spacer couples the diaphragm to the first top turn. ### Claim 19 (depends on 14) The method of claim 14, wherein curing the epoxy resin includes delivering an electrical current through the wire to heat-cure the epoxy resin.