JP5311061B2 - Voice coil and electrodynamic speaker using the same - Google Patents

Abstract

The invention provides a voice coil and an electrodynamic speaker. The electrodynamic speaker uses the tabulate voice coil in scroll direction vertical to the vibrating direction of a speaker vibration plate and is long and thin with short diameter being smaller than the long diameter. The electrodynamic speaker has superior voice reproduction capacity and is suitable for being mounted on equipment such as a display. The voice coil is formed by bonding end surfaces of the first and second coils as the tabulate hollow coils by way of making the first coil and second coils consistent with respective scrolls and connecting the bonded first and second coils in series or in parallel by way of flowing voice signal current in a same direction. The hollow coil is formed by winding the flat wire in multiple layers in a non-staggered manner relative to the scrolls and comprises a reinforcing board which is accommodated in an internal peripheral space regulated by an internal peripheral end part formed by bonding the first and second coils. The internal peripheral end part is matched with the external peripheral end part.

Description

  The present invention relates to an elongated voice coil and an electrodynamic loudspeaker whose short diameter direction is shorter than the long diameter direction. In particular, the present invention relates to a voice coil that is excellent in sound reproduction capability and suitable for being attached to a device such as a display, and an electrodynamic speaker using the same.

  In an audio device such as a display to which a speaker for reproducing sound is attached, it is desired to reduce the space required for attaching the speaker. In particular, an electrodynamic loudspeaker intended to be slender may be limited in slenderness depending on the configuration of the magnetic circuit. In addition, slender (rectangular, oval (including elliptical, track-shaped)) electrodynamic speakers employ a speaker magnetic circuit with a high magnetic flux density in the magnetic gap, where the diaphragm area is limited in the minor axis direction. When trying to do so, there is a disadvantage in the sound reproduction capability for various reasons such as the magnetic circuit is wider than the speaker diaphragm and cannot be downsized. Therefore, in order to solve these problems, various magnetic circuits for speakers and electrodynamic speakers using the same have been proposed.

  Conventionally, in order to reduce the thickness of an electrodynamic speaker, there is a speaker provided with a plate-like driving force transmission member on which a voice coil is formed. For example, a frame, a magnetic circuit fixed to the frame, a diaphragm fixed to the frame so as to vibrate in a predetermined direction, a driving force transmission member coupled to the diaphragm, and the driving force A damper that supports the transmission member, wherein the magnetic circuit is disposed between a first plane and a second plane, and the first plane is a plane parallel to the diaphragm. The second plane is defined as a plane that is parallel to the diaphragm and that is in contact with at least a part of the magnetic circuit. The driving force transmission member has a region where a voice coil is formed, and the driving force transmission member is generated by the action of a current flowing through the voice coil and a magnetic flux provided by the magnetic circuit. The driving force in a predetermined direction is transmitted to the diaphragm, and one end of the damper is coupled to the driving force transmission member at a position between the first plane and the second plane. And the other end of the damper is coupled to the frame at a position between the first plane and the second plane. (Patent Document 1).

  In addition, as a speaker including a plate-like driving force transmission member on which a voice coil is formed, for example, a plane vibration plate is attached to the back surface of the plane vibration plate along the vibration direction so that the plane is flat. There is a flat drive speaker comprising a drive plate on which a coil is formed and a magnet that applies a magnetic field to the coil of the drive plate, and the drive plate is a printed wiring board on which a coil is printed. (Patent Document 2).

  In addition, even if a plate-like driving force transmission member is not provided, a voice coil formed of a flat coil having two linear sides facing each other at the center of a rectangular or oval diaphragm A square dynamic formed by joining one linear side surface to a diaphragm so as to be substantially perpendicular to the plate, and arranging a magnetic circuit so that the magnetic flux interlinking with the voice coil is perpendicular to the coil plane. There is a speaker (Patent Document 3). Alternatively, a diaphragm that is supported so as to vibrate in a predetermined direction, a pair of magnets arranged opposite to each other in a direction orthogonal to the vibration direction of the diaphragm, and a direction parallel to each other of the pair of magnets A voice coil wound around the direction of the winding axis, and the voice coil is joined to the diaphragm at a portion where current flows in one direction perpendicular to the winding axis direction and the vibration direction. There is a speaker device in which a portion flowing in the other direction is arranged to face the pair of magnets (Patent Document 4).

Japanese Patent No. 3891481 (FIGS. 1 to 11) Japanese Utility Model Publication No. 58-48194 (FIGS. 1 to 3) Japanese Utility Model Publication No. 59-189398 (FIGS. 1 to 3) JP 2007-129665 A (FIGS. 1 to 9)

  However, it includes an elongated electrodynamic speaker having a shorter minor axis direction than the major axis direction, and includes a flat coil disposed so that the direction of the coil winding axis is orthogonal to the vibration direction of the speaker diaphragm. In this case, for example, when a plate-like driving force transmission member as in Patent Document 1 is provided, the weight of the speaker vibration system is increased, the magnetic flux density in the linear magnetic gap is reduced, and the sound is reduced. Problems such as a reduction in the reproduction efficiency of the speaker for reproducing the image may occur. On the other hand, for example, when the plate-like driving force transmission member as in Patent Document 4 is not provided, the driving force acting on the portion of the flat coil disposed in the magnetic gap of the magnetic circuit is affected by the rigidity of the flat coil. Due to the shortage, it is not sufficiently transmitted to the speaker diaphragm joined to the flat coil, the high frequency limit frequency is lowered and a sufficient sound reproduction band cannot be secured, and as a result, an electrodynamic speaker inferior in sound reproduction ability There is a problem of becoming.

  The present invention has been made to solve the above-described problems of the prior art, and an object of the present invention is to provide an electrokinetic motor using a flat coil having a winding direction perpendicular to the vibration direction of the speaker diaphragm. Type speaker, which is an elongated electrodynamic speaker with a shorter minor axis direction than the major axis direction, excellent voice reproduction capability, and suitable for mounting on devices such as displays, and an electrodynamic speaker. It is to provide.

  The voice coil of the present invention includes a first coil and a second coil, which are flat-plate air-core coils in which a rectangular wire is not shifted with respect to a winding axis, so that the respective winding axes coincide with each other. The first coil and the second coil that are formed by bonding end faces together and are connected in series or in parallel so that an audio signal current flows in the same direction. A reinforcing plate is provided that is accommodated in an inner circumferential space defined by an inner circumferential end formed by bonding the coil and the second coil, and that the outer circumferential end engages with the inner circumferential end.

  In addition, the voice coil of the present invention includes a first coil and a second coil, which are flat-plate air-core coils in which a flat wire is not shifted with respect to the winding axis, so that the respective winding axes coincide with each other. The coil end surfaces of the first coil and the second coil are bonded together in series or in parallel so that the audio signal current flows in the same direction. The inner peripheral end portion formed by bonding the first coil and the second coil is provided with a reinforcing plate with which the outer peripheral end portion is engaged, and the thickness of the reinforcing plate is bonded to the first coil and the second coil. It is smaller than the voice coil thickness dimension defined by the thickness.

  In the voice coil of the present invention, the inner peripheral end of the second coil has an inner diameter larger than the inner diameter of the inner peripheral end of the first coil, and the first coil and the second coil are bonded together. The inner peripheral end portion of the formed voice coil includes an engaging step portion with which the reinforcing plate is engaged.

  Preferably, in the voice coil according to the present invention, the second coil is formed by reducing the number of windings at the inner peripheral end of a flat-plate air core coil having the same number of turns as the first coil by one turn or more. The inner peripheral end of the first coil is configured to have an inner diameter larger than the inner diameter of the inner peripheral end of the first coil.

  More preferably, in the voice coil of the present invention, the reinforcing plate includes an engaging step portion that engages with an engaging step portion of the inner peripheral end portion of the voice coil at the outer peripheral end portion thereof.

  In the voice coil of the present invention, the reinforcing plate is made of resin or nonmagnetic metal.

  Preferably, in the voice coil of the present invention, the first coil and the second coil are either a track shape including a set of linear portions and a set of arc portions, or a rectangular shape including two sets of linear portions. The outer peripheral end portion of the reinforcing plate includes at least one set of linear portions that engage with the set of linear portions of the first coil and the second coil.

  The electrodynamic speaker of the present invention includes the above voice coil, a speaker diaphragm coupled to the voice coil, a magnetic circuit having a linear magnetic gap in which the voice coil is disposed, and a frame coupled to the magnetic circuit. And an edge for fixing the outer peripheral end of the frame to the frame and supporting the outer peripheral end of the speaker diaphragm.

  Preferably, the electrodynamic speaker of the present invention further includes a damper having an inner peripheral portion connected to the voice coil and an outer peripheral portion connected to a frame or a magnetic circuit.

  The operation of the present invention will be described below.

  The voice coil of the present invention is a flat air-core coil in which a rectangular wire having a rectangular cross section (including a square wire, a square wire, and an edgewise wire) is wound in multiple layers without shifting from the winding axis. It is a voice coil formed by bonding two coil end surfaces to each other so that the respective winding axes coincide with each other. The first coil and the second coil bonded together with an adhesive or varnish are connected in series or in parallel so that the audio signal current flows in the same direction. Therefore, the voice coil of the present invention is formed in a thin flat plate shape whose thickness is about twice the thickness of the flat wire. Although the first coil and the second coil wound in multiple layers without shifting the rectangular wire with respect to the winding axis have a problem that they are easily warped and deformed individually, each end face of each coil like the voice coil of the present invention. Bonding together prevents deformation and maintains a flat plate shape.

  A voice coil is formed into an elongated track shape or a rectangular shape as a whole, and when a part of the voice coil is arranged in a linear magnetic gap of a magnetic circuit, the minor axis direction is shorter than the major axis direction. Can be realized. The electrodynamic speaker of the present invention includes a speaker diaphragm connected to a voice coil, a frame connected to a magnetic circuit, and an edge that supports the outer peripheral end of the speaker diaphragm by fixing the outer peripheral end to the frame. Preferably, a damper having an inner peripheral portion connected to the voice coil and an outer peripheral portion connected to a frame or a magnetic circuit is provided.

  Since the first coil and the second coil, which are flat air-core coils, are formed in a track shape or a rectangular shape, the first coil and the second coil are bonded to the voice coil configured by bonding them together. An inner peripheral space defined by an inner peripheral end formed by the step. The voice coil of the present invention is provided with a reinforcing plate that is accommodated in the inner circumferential space and whose outer peripheral end engages with the inner peripheral end. The thickness of the reinforcing plate of the voice coil is made smaller than the voice coil thickness dimension defined by the thickness of the first coil and the second coil bonded together, and does not protrude from the inner space. In other words, the reinforcing plate of the voice coil is made smaller than the thickness dimension of the voice coil to which the first coil and the second coil are bonded, so that it does not protrude from the inner peripheral space defined by the inner peripheral end of the voice coil. To reinforce the voice coil. The voice coil is reinforced by forming the first coil and the second coil in either a track shape including a set of straight portions and a set of arc portions or a rectangular shape including two sets of straight portions. It is preferable that the outer peripheral end of the plate includes at least a set of linear portions that engage with a set of linear portions of the first coil and the second coil.

  Therefore, in the voice coil of the present invention, the rigidity can be increased by providing this reinforcing plate, and the driving force acting on the portion of the magnetic circuit of the voice coil that is disposed in the magnetic gap is the vibration of the speaker connected to the voice coil. Fully transmit the driving force to the plate. As a result, the electrodynamic speaker using this voice coil can secure a wide audio reproduction band by increasing the high frequency limit frequency. In addition, the reinforcing plate is made of resin or nonmagnetic metal and can be realized with a minimum volume accommodated in the inner space, so that the weight can be reduced, and a linear shape suitable for the thickness dimension of the voice coil can be obtained. It is not necessary to make it wider than the magnetic gap size, and a high magnetic flux density can be maintained. Therefore, it is possible to increase the sound reproduction efficiency and to make an electrodynamic speaker with excellent sound reproduction ability. Further, since the reinforcing plate increases the rigidity of the voice coil, there is an advantage that the flat voice coil is not warped and deformed.

  In the voice coil of the present invention, the track-shaped or rectangular inner peripheral end portion may include an engagement step portion with which the reinforcing plate is engaged. Specifically, if the inner peripheral end of the second coil has an inner diameter that is larger than the inner diameter of the inner peripheral end of the first coil to be bonded, a reinforcing plate is provided at the inner peripheral end. Engaging steps are formed. When the second coil is formed by reducing the number of turns at the inner peripheral end of a flat-plate air-core coil having the same number of turns as the first coil by one turn or more, it depends on the difference in the number of turns. An engagement step portion with which the reinforcing plate engages may be formed using the difference in the inner diameter dimension.

  Moreover, the reinforcing plate of the voice coil of the present invention may include an engaging step portion that engages with an engaging step portion of the inner peripheral end portion of the voice coil at the outer peripheral end portion thereof. The reinforcing plate having the engaging step at the outer peripheral end can be easily formed by molding a resin or press molding a nonmagnetic metal such as aluminum. Since the reinforcing plate having the engaging step at the outer peripheral end engages with the inner peripheral end of the first coil and the inner peripheral end of the second coil, the mounting accuracy of the reinforcing plate is increased and the rigidity is increased. Can be increased. Therefore, the voice coil of the present invention can balance the improvement in the reproduction efficiency of the electrodynamic speaker using the same and the slenderness, and can realize the electrodynamic speaker excellent in reproduction sound quality.

  The electrodynamic speaker using a flat coil having a winding direction perpendicular to the vibration direction of the speaker diaphragm, and in particular, a track shape formed by multilayer winding without shifting a rectangular wire with respect to the winding direction. This is an elongate electrodynamic speaker with a short coil direction shorter than the major axis direction, which has excellent sound reproduction capability and is suitable for mounting on devices such as displays, and electrodynamics. Type speakers can be provided.

It is a figure explaining the electrodynamic speaker 1 by preferable embodiment of this invention. Example 1 It is a partially expanded sectional view explaining the structure of the electrodynamic speaker 1 by preferable embodiment of this invention. Example 1 It is a figure explaining the voice coil 4 by preferable embodiment of this invention. Example 1 It is sectional drawing explaining the structure of the voice coil 4A by other preferable embodiment of this invention. (Example 2) It is sectional drawing explaining the structure of the voice coil 4B by other preferable embodiment of this invention. (Example 3) It is sectional drawing explaining the structure of the voice coil 40 of a comparative example. (Comparative example) It is a graph of the sound pressure frequency characteristic of the electrodynamic speaker using the voice coil 4A of an Example and the voice coil 40 of a comparative example. (Example 2, comparative example)

  Hereinafter, a voice coil and an electrodynamic speaker according to preferred embodiments of the present invention will be described, but the present invention is not limited to these embodiments.

1 and 2 are diagrams illustrating an electrodynamic speaker 1 according to a preferred embodiment of the present invention. Moreover, FIG. 3 is a figure explaining the voice coil 4 by preferable embodiment of this invention. Specifically, FIG. 1 is a perspective view of the electrodynamic speaker 1 viewed from the front side, and FIG. 2 is a partially enlarged view of the cross section of the electrodynamic speaker 1 in the minor axis direction. 3A is a side view of the voice coil 4 viewed from the minor axis direction, FIG. 3B is a cross-sectional view taken along the line CC ′ of the voice coil 4, and FIG. FIG. 3D is a development view illustrating the configuration of the voice coil 4. As will be described later, a part of the structure of the electrodynamic speaker 1, the internal structure, and the like are omitted. Further, the direction in which the straight line (long axis) connecting the points A-O-A ′ extends is the major axis direction, and the point B-O-B ′.
The direction in which the straight line (minor axis) connecting the two extends is the minor axis direction.

  The electrodynamic speaker 1 of the present embodiment is an elongated electrodynamic speaker having a track-shaped speaker diaphragm 2 having a major axis length L1 of about 135.6 mm and a minor axis direction length L2 of about 10 mm. Even if it is a shape, it is a speaker having a diaphragm area equivalent to a circular diaphragm having a diameter of about 35 mm. The outer peripheral end of the speaker diaphragm 2 is supported by an edge 3, and the outer peripheral end of the edge 3 is fixed to the frame 6. In addition, a coil 4 is connected to the central portion of the speaker diaphragm 2 from the back side, and the coil 4 is supported so as to be able to vibrate by a damper 5 whose outer peripheral side is fixed to a frame 6. The coil 4 of this embodiment is a track-type coil, and is a flat coil having a winding axis direction in a direction substantially orthogonal to the vibration direction in which the speaker diaphragm 2 vibrates. Further, the frame 6 has an elongated shape corresponding to the track-shaped speaker diaphragm 2, and the magnetic circuit 10 fixed so as to be accommodated in the frame 6 also has an elongated shape having a narrow width of the minor axis direction length L2 or less. Have. Therefore, the electrodynamic speaker 1 is a speaker suitable for a device with a small width for mounting the speaker, such as a side surface of a display unit included in a device such as a display. A terminal 7 (not shown) to which an audio signal current is supplied is attached to the back side of the frame 6 and a part of the magnetic circuit 10 is exposed.

  The speaker diaphragm 2 of the electrodynamic speaker 1 has an inner peripheral side of an edge 3 bonded to an outer peripheral end thereof, and one linear portion 4b of a track-shaped coil 4 to be described later is slit on the center rear surface. It is inserted into the connection part in the shape and bonded with an adhesive. The speaker diaphragm 2 is formed by forming a foamed thermoplastic resin in order to reduce the weight of the speaker diaphragm. In the case of the present embodiment, the speaker diaphragm 2 having irregularities is obtained by using a vacuum forming method in which a thermoplastic resin foam sheet (specifically, polystyrene paper) that has been extruded is combined with plug assist molding. It has gained. That is, in the elongated speaker diaphragm 2 in which the major axis direction length L1 and the minor axis direction length L2 are remarkably different, the influence of divided vibration in the major axis direction is likely to be noticeable, so the minor axis direction cross-sectional shape includes a substantially U-shape. Thus, the shape has rigidity in the major axis direction.

  In this embodiment, the edge 3 is formed by injecting flexible foam rubber into a mold and heating and foaming. The long side of the track shape that extends linearly in the major axis direction of the speaker diaphragm 2 and the short side of the track shape that has an arc shape in the minor axis direction have a thin corrugation (or so as to freely support the speaker diaphragm 2). A free edge is formed by a roll. Note that, in the short side of the track shape, the edge that is arcuate in the minor axis direction may be formed as a fixed edge that is thick and does not vibrate freely so as to fix and support the speaker diaphragm 2. . As a result, the elongated speaker diaphragm 2 is flexibly supported by the compliance of the free edge portion of the edge 3 in the minor axis direction, while the thermoplastic resin foam sheet that forms the speaker diaphragm 2 in the major axis direction. Flexibility enables bending vibration.

  The coil 4 corresponds to a magnetic circuit 10 to be described later, and is a flat coil having a winding direction in a direction substantially orthogonal to a vibration direction in which the speaker diaphragm 2 vibrates, and has a major axis length of about The coil has a track shape of 36.2 mm, a minor axis length of about 8.2 mm, and a thickness of 4 t of about 0.5 mm. Specifically, the coil 4 has a thickness (41t to 42t = about 0.25 mm) in which a copper rectangular wire having a thickness of 0.12 mm × 0.20 mm is wound in multiple layers without shifting with respect to the winding axis. It includes two air-core coils 41 and 42 formed in a flat plate shape approximately equal to the thickness of the flat wire and having a winding layer thickness of about 2.3 mm, and a reinforcing plate 43 described later. The coils 41 and 42 constituting the coil 4 of this embodiment are coils having the same number of turns. The coil 4 is formed by bonding the coil end surfaces with an adhesive (or varnish) so that the winding axes of the coils 41 and 42 coincide with each other, and the bonded coils 41 and 42 are voiced in the same direction. It is a voice coil configured to be connected in series so that a signal current flows. Since the coils 41 and 42 are wound in multiple layers without shifting the rectangular wire with respect to the winding axis, there is a problem that each of the coils 41 and 42 is easily warped and deformed. It can prevent and keep a flat plate shape.

  In the track-shaped coil 4 to which the coils 41 and 42 are bonded, one linear portion 4a, the other linear portion 4b, one arc portion 4c, and the other arc portion 4d are formed to form a track shape. An inner peripheral space 4f which is a track-shaped hole is formed on the inner peripheral side of the inner peripheral end 4e. Therefore, in the coil 4, the outer peripheral end 43e of the reinforcing plate 43 accommodated in the inner peripheral space 4f is engaged with the track-shaped inner peripheral end 4e. The reinforcing plate 43 has an outer peripheral end 43e engaged with the track-shaped inner peripheral end 4e of the coil 4 and is bonded with an adhesive. That is, the outer peripheral end 43 e of the reinforcing plate 43 engages with the inner peripheral surface of the innermost winding of the coils 41 and 42. The reinforcing plate 43 of this embodiment is an aluminum plate having a thickness 43t of about 0.4 mm, and has a track shape with a major axis length of about 31.5 mm and a minor axis length of about 3.5 mm. Since the thickness 43t of the reinforcing plate 43 is made smaller than the voice coil thickness dimension 4t defined by the thickness of the coils 41 and 42 bonded together, the reinforcing plate 43 does not protrude from the inner peripheral space 4f of the coil 4. Since the reinforcing plate 43 increases the rigidity of the coil 4, it suppresses deformation that causes the flat coil 4 to warp. The reinforcing plate 43 may be made of a nonmagnetic metal such as copper, duralumin, or an aluminum alloy, but may be made of a synthetic resin such as ABS, PI, or PET.

  The damper 5 is provided with a notch portion (slit portion) in a thin resin plate, and connects the inner fixing portion connected to the coil 4, the outer fixing portion connected to the frame 6, and the inner fixing portion and the outer fixing portion. And an arm-shaped movable part. Specifically, the damper 5 is a member formed by pressing a PC resin plate having a thickness of about 0.2 mm. The inner fixing portion includes an arc portion 4c to an arc portion 4d of the coil 4 and a coil. The four reinforcing plates 43 are inserted and fixed. The damper 5 is connected to the coil 4 or the frame 6 by an adhesive. The damper 5 may be a damper formed by injection molding of a resin, or may be formed by impregnating a phenol resin with a flexible fiber woven fabric as a base material.

  The frame 6 is a resin that is injection-molded into an elongated basket shape corresponding to the shape of the speaker diaphragm 2, a substantially rectangular fixing portion that fixes the edge 3, a fixing portion that fixes the magnetic circuit 10, A connecting portion for connecting these fixing portions, a window defined between the plurality of connecting portions, and a mounting hole for attaching a terminal (not shown) are provided. Therefore, the speaker vibration system including the speaker diaphragm 2, the edge 3, the coil 4, and the damper 5 is supported so as to be able to vibrate with respect to the frame 6 and the magnetic circuit 10. The frame 6 may be a metal frame formed by press-molding a steel plate.

  The magnetic circuit 10 includes yokes 11 and 12 that form a linear magnetic gap 14, and a bar-shaped magnet 13 having a rectangular cross section sandwiched between the yokes 11 and 12. The magnet 13 of this embodiment is a rod-like rare earth magnet and is magnetized so that each plane connected to the yoke 11 or 12 has a different magnetic pole property. Therefore, a magnetic field having a high magnetic flux density is formed in the linear magnetic gap 14. Is generated. Each member constituting the magnetic circuit 10 is fixed with an adhesive. The magnetic circuit 10 is also fixed to the fixing portion of the frame 6 with an adhesive. The magnetic circuit 10 is an elongated magnetic circuit having an outer dimension with a major axis length of about 31.0 mm and a minor axis direction length of about 5.7 mm, and is almost entirely inside the frame 6 viewed from the front. Since the size is accommodated, the electrodynamic speaker 1 can be elongated. The magnetic circuit 10 is not limited to the configuration of this embodiment as long as it forms a linear magnetic gap 14.

  In the electrodynamic speaker 1 of the present embodiment, the coil 4 includes a track-shaped linear portion 4 a disposed in the linear magnetic gap 14 of the magnetic circuit 10, and the other linear portion 4 b of the speaker diaphragm 2. Connect to the center. Also, a damper 5 described later is connected to one arc portion 4c, the other arc portion 4d, and the reinforcing plate 43. In the present embodiment, the two coils 41 and 42 to be bonded together constituting the coil 4 are mutually the same as the bonded portions (for example, one linear portion 4a of the coil 41 and one linear portion 4a of the coil 42). They are connected in series so that the audio signal current flows in the direction. Of course, the coils 41 and 42 may be connected in parallel. In addition, the tinsel wire (not shown) connected to the coil 4 is electrically connected to the coil 4 by soldering a terminal (not shown) fixed to the frame 6 and a lead wire of the coil 4 from the terminal. Supply current. However, the tinsel wire may be electrically connected to the terminal by providing a metal eyelet on the speaker diaphragm 2.

  When an audio signal current is supplied to the coil 4 in the electrodynamic speaker 1, a driving force acts on one linear portion 4 a of the coil 4 disposed in the linear magnetic gap 14 of the magnetic circuit 10. The coil 4 includes the reinforcing plate 43 that is engaged between the one linear portion 4a and the other linear portion 4b, thereby reinforcing the coils 41 and 42 and increasing the rigidity. Therefore, the driving force acting on the portion (one linear portion 4 a of the coil 4) disposed in the magnetic gap 14 of the magnetic circuit 10 of the coil 4 is applied to the speaker diaphragm 2 connected to the other linear portion 4 b of the coil 4. Well communicated. As a result, the electrodynamic speaker 1 using this coil 4 can secure a wide audio reproduction band by increasing the high frequency limit frequency.

  Further, the reinforcing plate 43 is made of resin or nonmagnetic metal and can be realized with the minimum volume accommodated in the inner circumferential space, so that the weight can be reduced, and a straight line suitable for the thickness dimension 4t of the coil 4 can be obtained. It is not necessary to make it wider than the magnetic gap size, and a high magnetic flux density can be maintained. The reinforcing plate 43 of the present embodiment is a track-shaped flat plate that can be easily processed. However, a weight reduction may be achieved by providing a through hole or a meat stealer. Therefore, it is possible to increase the sound reproduction efficiency and to make the electrodynamic speaker 1 having excellent sound reproduction ability.

  FIG. 4 is a diagram for explaining another coil 4A that can constitute the electrodynamic speaker 1 in place of the coil 4 of the previous embodiment, and corresponds to the CC corresponding to FIG. 3B of the previous embodiment. 'Cross section. The coil 4A of this embodiment has the same configuration as the coil 4 of the previous embodiment, includes two air-core coils 41a and 42a, and a reinforcing plate 43a described later, and has substantially the same outer dimensions. It is a flat plate-shaped coil. However, the coil 4A includes a dimension 41r of the inner peripheral end of one air-core coil 41a that forms the track-shaped inner peripheral end 4e, and a dimension 42r of the inner peripheral end of the other air-core coil 42a. The thickness 43t of the reinforcing plate 43a and the dimension of the outer peripheral end 43e of the reinforcing plate 43a are different from those of the coil 4 of the previous embodiment in that they are different. Therefore, common portions are denoted by common numbers and description thereof is omitted.

  The coil 4A is formed by bonding the coil end surfaces to each other so that the winding axes of the coils 41a and 42a coincide with each other with an adhesive (or varnish). The coils 41a and 42a are wound in multiple layers without shifting a copper rectangular wire having a thickness of 0.12 mm × 0.20 mm with respect to the winding axis. The track-shaped coil 41a has approximately 25 turns, and has an inner peripheral end portion dimension 41r that is a distance of the inner peripheral space 4f defined between one linear portion 4a and the other linear portion 4b. , About 3.5 mm. The other track-shaped coil 42a has about 22 turns and has an inner circumferential end that is the distance of the inner circumferential space 4f defined between the one linear portion 4a and the other linear portion 4b. The dimension 42r of the portion is about 4.7 mm, and the inner diameter dimension 42r of the inner peripheral end portion of the coil 42a is larger than the inner diameter dimension 41r of the inner peripheral end portion of the coil 41a. The coil 42a is formed by reducing the number of windings at the inner peripheral end of a flat air-core coil having the same number of turns as the coil 41a by three turns. As a result, the coil 4A of the present embodiment is formed such that the inner peripheral end 4e formed by bonding the coils 41a and 42a includes an engaging step portion with which the reinforcing plate 43 is engaged.

  That is, the engaging step portion of the inner peripheral end 4e of the coil 4A is formed by the difference in the inner diameter dimensions 41r and 42r of the inner peripheral ends of the coils 41a and 42a to be bonded together. When the coils 41a and 42a are formed using coils having the same number of turns, the winding at the inner peripheral end of one coil may be rewound so as to be reduced by one turn or more. Therefore, as shown in FIG. 4, the reinforcing plate 43a constituting the coil 4A of the present embodiment is engaged with the inner peripheral end 4e including the engaging step portion of the coil 4A. That is, the outer peripheral end portion 43e of the reinforcing plate 43a engages with the coil end surface of the innermost winding of the coil 41a and the inner peripheral surface of the innermost winding of the coil 42b.

  The reinforcing plate 43a is an aluminum plate that is about half as thin as the previous embodiment, and has a thickness 43t of about 0.2 mm, a major axis length of about 31.5 mm, and a minor axis. The track length has a direction length of about 4.7 mm. Since the thickness of the reinforcing plate 43a of the present embodiment is made smaller than the voice coil thickness dimension 42t of the coil 42a, the reinforcing plate 43a does not protrude from the inner peripheral space 4f of the coil 4A. Since the reinforcing plate 43a increases the rigidity of the coil 4, it suppresses deformation such that the flat coil 4 warps. Further, since the reinforcing plate 43a reinforces the coils 41a and 42b to increase the rigidity, the driving force acting on one linear portion 4a disposed in the magnetic gap 14 of the magnetic circuit 10 of the coil 4A is applied to the other side of the coil 4A. Is sufficiently transmitted to the speaker diaphragm 2 connected to the linear portion 4b. As a result, the electrodynamic speaker 1 using this coil 4A can secure a wide audio reproduction band by increasing the high frequency limit frequency. In addition, since the reinforcing plate 43a can be made about half as thin as the previous embodiment, the weight can be further reduced. If the speaker vibration system including the coil 4A can be reduced in weight, it is possible to increase the sound reproduction efficiency and realize the electrodynamic speaker 1 having excellent sound reproduction ability.

  FIG. 5 is a diagram for explaining another coil 4B that can constitute the electrodynamic speaker 1 in place of the coil 4A of the previous embodiment, and is a cross-sectional view along CC ′ corresponding to FIG. 4 of the previous embodiment. It is. The coil 4B of this embodiment has the same configuration as the coil 4A of the previous embodiment, includes two air-core coils 41a and 42a, and a reinforcing plate 43b described later, and has substantially the same outer dimensions. It is a flat plate-shaped coil. That is, the coil 4B has a dimension 41r of the inner peripheral end of one air-core coil 41a that forms the track-shaped inner peripheral end 4e, and a dimension 42r of the inner peripheral end of the other air-core coil 42a. Is different from the coil 4A of the previous embodiment in that an engagement step of the inner peripheral end 4e is formed. On the other hand, in the coil 4B, the shape of the reinforcing plate 43b is different from the shape of the reinforcing plate 43a of the coil 4A of the previous embodiment. Therefore, common portions are denoted by common numbers and description thereof is omitted.

  The reinforcing plate 43b is an aluminum plate that is about half as thin as the reinforcing plate 43 of the previous embodiment, has a thickness 43t of about 0.2 mm, and has a major axis length of about 31.5 mm. A track shape with a minor axis length of about 4.7 mm. Further, as shown in the drawing, the reinforcing plate 43b includes an engaging step portion that engages with an engaging step portion of the inner peripheral end portion 4e of the coil 4B at the outer peripheral end portion 43e. That is, the engagement step portion formed on the outer peripheral end portion 43e of the reinforcing plate 43b is associated with the engagement step portion of the inner peripheral end portion 4e of the coil 4B formed by the two air-core coils 41a and 42a. Match. Since the reinforcing plate 43b is formed with a rising engagement step portion at the outer peripheral end portion 43e, the rigidity is further improved as compared with the reinforcing plate 43a of the previous embodiment.

  As described above, the reinforcing plate 43b further increases the rigidity of the coil 4B. Therefore, the reinforcing plate 43b suppresses deformation such that the flat coil 4 is warped and reinforces the coils 41a and 42b to increase the rigidity. As a result, in the electrodynamic speaker 1, the driving force acting on one linear portion 4a of the coil 4B disposed in the magnetic gap 14 of the magnetic circuit 10 of the coil 4B is coupled to the other linear portion 4b of the coil 4B. It is sufficiently transmitted to the speaker diaphragm 2. The electrodynamic speaker 1 using the coil 4B can secure a wide audio reproduction band by further increasing the high frequency limit frequency.

  Since the thickness 43t of the reinforcing plate 43b of this embodiment can be made smaller than the voice coil thickness dimension 4t defined by the thickness of the coils 41a and 42a bonded together, the choice of the material thickness of the reinforcing plate 43b increases, Light weight can be realized. That is, as in the present embodiment, an engagement step portion is provided at the outer peripheral end portion 43e of the reinforcing plate 43b, and only the thickness of the engaging step portion of the outer peripheral end portion 43e of the reinforcing plate 43b is the voice coil thickness of the coil 42a. If it is smaller than the dimension 42t, the thickness 43t of the reinforcing plate 43b of the present embodiment is selected from a range that is larger than the voice coil thickness dimension 42t of the coil 42a and smaller than the thickness 4t where the coils 41a and 42a are bonded together. Can do. In this way, since the reinforcing plate 43b does not protrude from the inner circumferential space 4f of the coil 4B, the electrodynamic speaker 1b does not need to increase the size of the linear magnetic gap 14 of the magnetic circuit 10, and has a high magnetic flux density. Can keep.

  FIG. 6 is a diagram illustrating a comparative coil 40 corresponding to the coil 4 of the previous embodiment. Specifically, FIG. 6A is a CC ′ cross-sectional view corresponding to FIG. 3B of the previous embodiment of the coil 40 of the comparative example, and FIG. 3 is a perspective view of a coil 40. FIG. The coil 40 of the comparative example is a voice coil that does not include the reinforcing plate 43 as compared with the coil 4 of the previous embodiment. That is, in the coil 40 of the comparative example, the two air-core coils 41 and 42 formed in a flat plate shape with the same number of turns are respectively connected to each other so that the winding axes of the coils 41 and 42 coincide with each other with an adhesive (or varnish). The coil end surfaces are bonded to each other, and the bonded coils 41 and 42 are connected in series so that an audio signal current flows in the same direction.

  Therefore, an inner peripheral space 4f that is a track-shaped hole is formed on the inner peripheral side of the track-shaped inner peripheral end 4e of the coil 40 of the comparative example. Since the coil 40 of the comparative example does not include a reinforcing plate that increases the rigidity, as a result, in the electrodynamic speaker using the coil 40 of the comparative example, the linear portion disposed in the magnetic gap 14 of the magnetic circuit 10 of the coil 40. The driving force acting on 4a is not sufficiently transmitted to the speaker diaphragm 2 connected to the other linear portion 4b of the coil 40.

  FIG. 7 is a graph of the sound pressure frequency characteristics of the electrodynamic speaker 1 using the voice coil 4A of the example and the voice coil 40 of the comparative example. As indicated by the solid line, the electrodynamic speaker 1 using the coil 4A of the embodiment can secure a wide audio reproduction band by increasing the high-frequency limit frequency. On the other hand, as shown by a broken line, in the electrodynamic speaker 1 using the coil 40 of the comparative example, the high frequency limit frequency becomes low, a high peak occurs in the vicinity of about 6 kHz, and a wide audio reproduction band cannot be secured. .

  In the electrodynamic speaker 1 using the coils 4, 4 </ b> A, or 4 </ b> B according to the embodiment, since the coil includes the reinforcing plate, the rigidity of the voice coil is increased and the configuration of the vibration system including the speaker diaphragm 2 is stabilized. . As a result, even if the electrodynamic speaker 1 of the present embodiment is an elongated electrodynamic speaker in which the operation of the vibration system is likely to be unstable, the voice coil is in contact with the magnetic gap 14 of the magnetic circuit 10. It is possible to suppress problems that cause abnormal noise and cause malfunction.

  In the coils 4, 4A to 4B of the embodiment, the reinforcing plates 43, 43a to 43b are formed in a track shape corresponding to the track shape of the inner peripheral end 4e of the coil. However, the reinforcing plate may have a rectangular shape that connects one linear portion 4a of the track shape and the other linear portion 4b. The reinforcing plate may have another shape corresponding to the shape of the inner peripheral end of the coil. For example, when the coil is rectangular, the reinforcing plate that further improves the rigidity may be rectangular.

  In the electrodynamic speaker 1, the flat coil 4 is supported by the integrally formed damper 5 so as to be able to vibrate, but may be a damper 5 of another form. For example, the damper 5 may support the end of the coil 4 in the major axis direction so as to be able to vibrate by other forms of dampers 51 and 52, and the damper 5 can suppress the rolling of the coil 4. It is not necessary to prepare.

  The electrodynamic speaker of the present invention can be applied not only as a speaker built in video / audio equipment such as a display but also to a game machine having a cabinet with a built-in speaker for reproducing sound, a game machine such as a slot machine, etc. It is. In addition, the electrodynamic speaker provided with the magnetic circuit for a speaker according to the present invention has a narrow overall width and can realize a speaker system that reproduces sound in a small and thin cabinet. Suitable.

DESCRIPTION OF SYMBOLS 1 Electrodynamic type speaker 2 Speaker diaphragm 3 Edge 4, 4A, 4B, 40 Coil 41, 41a Coil 42, 42a Coil 43, 43a, 43b Reinforcement plate 5 Damper 6 Frame 10 Magnetic circuit 11, 12 Yoke 13 Magnet

Claims (9)

The first coil and the second coil, which are flat-plate air-core coils wound in multiple layers without shifting the rectangular wire with respect to the winding axis, are bonded to each other so that the respective winding axes coincide with each other. The first coil and the second coil that are formed and bonded together are a voice coil configured to be connected in series or in parallel so that an audio signal current flows in the same direction,
A reinforcing plate is provided that is accommodated in an inner peripheral space defined by an inner peripheral end formed by bonding the first coil and the second coil, and that the outer peripheral end engages with the inner peripheral end. ,
Voice coil. The first coil and the second coil, which are flat-plate air-core coils wound in multiple layers without shifting the rectangular wire with respect to the winding axis, are bonded to each other so that the respective winding axes coincide with each other. The first coil and the second coil that are formed and bonded together are a voice coil configured to be connected in series or in parallel so that an audio signal current flows in the same direction,
The inner peripheral end formed by bonding the first coil and the second coil is provided with a reinforcing plate that engages with the outer peripheral end, and the thickness of the reinforcing plate is the first coil and the second coil. Smaller than the voice coil thickness dimension defined by the thickness of the laminated coil,
Voice coil. The voice formed by bonding the first coil and the second coil, wherein an inner peripheral end of the second coil has an inner diameter larger than an inner diameter of the inner peripheral end of the first coil. The inner peripheral end portion of the coil includes an engagement step portion with which the reinforcing plate is engaged.
The voice coil according to claim 1 or 2. The second coil is formed by reducing the number of turns of the inner peripheral end of a flat-plate air-core coil having the same number of turns as the first coil by one turn or more, and the inner peripheral end of the second coil is It is comprised so that it may have an internal diameter dimension larger than the internal diameter dimension of the inner peripheral end part of a 1st coil.
The voice coil according to claim 3. The reinforcing plate includes an engaging step portion that engages with the engaging step portion of the inner peripheral end portion of the voice coil at the outer peripheral end portion thereof.
The voice coil according to claim 3 or 4. The reinforcing plate is made of resin or non-magnetic metal,
The voice coil according to claim 1. The first coil and the second coil are formed in one of a track shape including a set of linear portions and a set of arc portions, or a rectangular shape including two sets of linear portions, and the reinforcing plate The outer peripheral end portion includes at least a set of linear portions that engage with the set of linear portions of the first coil and the second coil,
The voice coil according to claim 1. The voice coil according to any one of claims 1 to 7,
A speaker diaphragm coupled to the voice coil;
A magnetic circuit having a linear magnetic gap in which the voice coil is disposed;
A frame coupled to the magnetic circuit;
An edge for fixing the outer peripheral end of the frame to the frame and supporting the outer peripheral end of the speaker diaphragm;
Electrodynamic type speaker with An inner periphery connected to the voice coil, and an outer periphery further includes a damper connected to the frame or the magnetic circuit;
The electrodynamic speaker according to claim 8.

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