WO2024057596A1

WO2024057596A1 - Electroacoustic transducer

Info

Publication number: WO2024057596A1
Application number: PCT/JP2023/014619
Authority: WO
Inventors: 将史西田; 一平來山
Original assignee: パナソニックＩｐマネジメント株式会社
Priority date: 2022-09-13
Filing date: 2023-04-10
Publication date: 2024-03-21

Abstract

This electroacoustic transducer (100) comprises a magnetic circuit (110), a coil (120), an oscillation plate (130), a frame (140), and an edge (150). The edge (150) includes: an up-roll portion (151) which curves to protrude toward a front side, which is one side of an oscillation direction of the oscillation plate (130); and a down-roll portion (152) which is connected concentrically to the up-roll portion (151) and which curves so as to protrude toward a rear side, which is the other side of the oscillation direction. The up-roll portion (151) includes a first bulging line (161) which protrudes toward the rear side and the down-roll portion (152) includes a second bulging line (162) which protrudes toward the front side. The inclination of the first bulging line (161) and the inclination of the second bulging line (162) are the same when viewed from the front side.

Description

electroacoustic transducer

The present disclosure relates to a device that converts acoustic vibrations into a change in electrical quantity, such as a microphone, or a device that converts a change in electrical quantity acoustically, such as a speaker.

Conventionally, in a speaker, which is an electroacoustic transducer, an edge that supports a vibrating diaphragm protrudes toward the front in order to equalize the amount of air displacement due to the amplitude in the front and back direction and suppress secondary distortion. Patent Document 1 describes a configuration in which an up roll portion and a down roll portion protruding toward the rear side are provided concentrically at the edge.

Japanese Unexamined Patent Publication No. 6-178387

However, if a speaker uses an edge that includes an up-roll portion and a down-roll portion concentrically, resonance may occur.

Therefore, the present disclosure solves this problem by adopting an edge that includes an up-roll part and a down-roll part concentrically to equalize the amount of air removed when the edge vibrates, while suppressing resonance and increasing the frequency. The object of the present invention is to provide an electroacoustic transducer with improved characteristics.

To achieve this objective, an electroacoustic transducer according to one aspect of the present disclosure includes a magnetic circuit, a coil disposed in a magnetic gap of the magnetic circuit, a diaphragm to which the coil is connected, and a diaphragm connected to the magnetic circuit. An up roll comprising: a frame holding a circuit; and an edge connecting the diaphragm and the frame, the edge being curved so as to protrude toward the front side, which is one side in the vibration direction of the diaphragm. and a down roll part that is concentrically connected to the up roll part and curved so as to protrude toward the rear side, which is the other side in the vibration direction, and the up roll part has a front and rear direction. A plurality of linear first bulging strips are provided on the down roll portion, and a linear second bulging strip is provided on the down roll portion. When a plurality of bulging strips are provided and the first bulging strip and the second bulging strip have different protruding directions, the first bulging strip is different from the first bulging strip with respect to the radial direction centered on the winding axis of the coil. and the second bulging strip are inclined in the same direction, and when the protruding direction of the first bulging strip and the second bulging strip are the same, the first bulging strip is tilted in the same direction with respect to the radial direction centered on the winding axis. The bulging strip and the second bulging strip are tilted in different directions.

According to the present disclosure, it is possible to suppress torsional vibration of the diaphragm and improve the frequency characteristics of the electroacoustic transducer.

FIG. 2 is a cross-sectional view showing an electroacoustic transducer. FIG. 3 is a plan view showing the electroacoustic transducer from the front side. It is a perspective view showing an edge. FIG. 3 is a perspective view showing one of the first bulging strips from the diagonally front side. It is a perspective view showing one of the first bulges from the diagonally rear side. FIG. 7 is a diagram showing another example 1 of the arrangement pattern of bulging stripes. FIG. 7 is a diagram showing another example 2 of the arrangement pattern of bulging stripes. It is a top view which shows another example of an edge from the front side.

Hereinafter, embodiments of the electroacoustic transducer will be described with reference to the drawings. Note that the following embodiments are given as an example to explain an electroacoustic transducer, and are not intended to limit the electroacoustic transducer. For example, the shapes, structures, materials, components, relative positional relationships, connection states, numerical values, formulas, contents of each step in the method, order of each step, etc. shown in the following embodiments are merely examples. It may contain content not listed in . Furthermore, although geometric expressions such as parallel and perpendicular are sometimes used, these expressions do not indicate mathematical rigor and include substantially permissible errors, deviations, and the like. Furthermore, expressions such as "simultaneously" and "identical" also include a substantially permissible range.

In addition, the drawings are schematic diagrams with emphasis, omission, or ratio adjustment as appropriate for explaining the present disclosure, and the actual shapes, positional relationships, and ratios differ. Further, the X-axis, Y-axis, and Z-axis that may be shown in the drawings indicate orthogonal coordinates arbitrarily set for the purpose of explaining the drawings. In other words, the Z-axis is not necessarily an axis along the vertical direction, and the X-axis and Y-axis are not necessarily in a horizontal plane.

Further, below, multiple inventions may be comprehensively described as one embodiment. Further, some of the contents described below are described as optional components related to the present disclosure.

FIG. 1 is a sectional view showing an electroacoustic transducer 100. FIG. 2 is a plan view showing the electroacoustic transducer 100 from the front side. Note that FIG. 1 is a cross-sectional view taken along a plane including the winding axis 122 (the central axis of the coil) of the coil 120. Hatching in FIG. 2 does not mean a cross section, but is used to distinguish between an up roll portion 151 (described later) and a down roll portion 152 (described later), and is applied to the down roll portion 152. Further, the front side (Z+ side in the figure) is the side opposite to the magnetic circuit 110 with respect to the diaphragm 130 in the direction of the winding axis 122 of the coil 120, and is the side from which sound is emitted. Note that the side on which the magnetic circuit 110 is arranged with respect to the diaphragm 130 is the rear side (Z- side in the figure).

In the case of this embodiment, the electroacoustic transducer 100 is exemplified by a so-called speaker that converts an acoustic signal, which is a change in electrical quantity, into acoustic vibration, which is air vibration. The electroacoustic transducer 100 includes a magnetic circuit 110, a coil 120, a diaphragm 130, a frame 140, an edge 150, and a damper 170.

The magnetic circuit 110 includes a cylindrical magnet 111 that is a magnetized permanent magnet, a disc-shaped top plate 112 attached to the front side of the magnet 111, and a bottomed cylinder that accommodates the magnet 111 and the top plate 112. The yoke 113 has a shape. Yoke 113 is attached to the rear side of magnet 111. Due to the gap between the top plate 112 and the yoke 113, the magnetic circuit 110 forms an annular magnetic gap 114. A steady magnetic flux generated by the magnet 111 is generated in the magnetic gap 114 . In this embodiment, the magnetic circuit 110 is of an internal magnetic type, but the magnetic circuit 110 included in the electroacoustic transducer 100 may be of an external magnetic type.

The coil 120 is a coil into which an acoustic signal is input. The coil 120 is arranged within the magnetic gap 114 such that the winding axis 122 of the coil 120 and the tube axis of the magnetic gap 114 formed by the magnetic circuit 110 coincide. In the case of this embodiment, the coil 120 is wound around the outer periphery of a cylindrical bobbin 121, and is connected to the diaphragm 130 via the bobbin 121. The coil 120 reciprocates in the direction of the winding shaft 122 (Z-axis direction in the figure) due to the magnetic flux that changes in response to the audio signal generated in the coil 120.

The diaphragm 130 is a member that vibrates based on the vibration of the coil 120 and generates acoustic vibrations, that is, air vibrations. The shape of the diaphragm 130 is not limited, and may be a disk shape or the like. In the case of the present embodiment, the diaphragm 130 has a truncated cone shape, that is, a so-called cone shape, and a penetrating diaphragm hole 131 into which the bobbin 121 is inserted is provided in the center. Furthermore, a dome-shaped cap 132 that covers the diaphragm hole 131 is attached to the diaphragm 130 .

The frame 140 is a structural member that holds the magnetic circuit 110 fixedly and holds the diaphragm 130 so that it can vibrate. The frame 140 includes an annular edge 141 surrounding the outer periphery of the diaphragm 130, a holding portion 142 that holds the magnetic circuit 110, and a connecting portion 143 that connects the edge 141 and the holding portion 142. .

The damper 170 is an elastic member that supports the diaphragm 130 together with the edge 150 so that the diaphragm 130 can vibrate linearly in the direction of the winding axis 122 of the coil 120. In the present embodiment, the damper 170 is attached in a bridging manner between the bobbin 121 and the connecting portion 143 of the frame 140, and supports the diaphragm 130 against the frame 140 via the bobbin 121. Note that the electroacoustic transducer 100 does not necessarily have to include the damper 170.

FIG. 3 is a perspective view showing the edge 150. The edge 150 is an elastic member that vibrably connects the diaphragm 130 to the frame 140. The material of the edge 150 is not limited, but examples include rubber and elastomer. The edge 150 includes an up roll portion 151 and a down roll portion 152. In the case of this embodiment, the edge 150 includes a first attachment part 153 that is attached to the edge 141 of the frame 140 with an adhesive or the like, and a second attachment part 154 that is attached to the diaphragm 130 with an adhesive or the like. ing.

The up-roll portion 151 is a portion that protrudes toward the front side that is one side (Z+ side in the figure) in the vibration direction (Z-axis direction in the figure) of the diaphragm 130, and is a portion that curves in an arc shape. The cross-sectional shape of the up-roll portion 151 in a plane including the winding shaft 122 of the coil 120 is the same arcuate shape over the entire circumference except for the bulging strip (details will be described later). The up roll portion 151 is provided with a first bulging strip 161. In the case of this embodiment, the up roll section 151 is arranged concentrically inside the down roll section 152 and is integrally connected to the down roll section 152.

The down roll portion 152 is a portion that protrudes toward the rear side that is the other side (Z- side in the figure) in the vibration direction (Z-axis direction in the figure) of the diaphragm 130, and is a portion that curves in an arc shape. . The cross-sectional shape of the down roll portion 152 in a plane including the winding shaft 122 of the coil 120 is the same arc shape over the entire circumference except for the bulging strip (details will be described later). The down roll portion 152 is provided with a second bulging strip 162. In the case of this embodiment, the up roll section 151 is arranged concentrically inside the down roll section 152 and is integrally connected to the down roll section 152.

The cross-sectional shape and size of the up-roll portion 151 and the cross-sectional shape and size of the down-roll portion 152 in a cross section including the winding shaft 122 of the coil 120 are set by detailed design, but in the case of this embodiment. are set the same. Since the down roll part 152 is arranged concentrically outside the up roll part 151, the volume of the area surrounded by the down roll part 152 is larger than the volume of the area surrounded by the up roll part 151. However, the inventor discovered that when the diaphragm 130 vibrates, the amount of air removed by the up roll section 151 and the amount of air removed by the down roll section 152 are equal, improving power linearity and suppressing an increase in secondary distortion. , is heading. This is because the amplitude of the down roll portion 152 near the first attachment portion 153 attached to the edge 141 of the frame 140 is smaller than the amplitude of the up roll portion 151 farther from the first attachment portion 153.

FIG. 4 is a perspective view showing one of the first bulging stripes 161 from the oblique front side. FIG. 5 is a perspective view showing one of the first bulging strips 161 from the oblique rear side. In a plan view seen from the front side, the up-roll portion 151 has a plurality of linearly bulging portions that are inclined in the same direction with respect to the radial direction (broken line in FIG. 2) centered on the winding axis 122 of the coil 120. A first bulging strip 161 is provided. Similarly, the down roll portion 152 is provided with a second bulging strip 162. The first bulging line 161, which is a bulging line, bulges in a line from the surface of the up roll part 151 in either the front or back direction in the direction of the winding shaft 122 (broken line in FIGS. 4 and 5). It is a part. Moreover, as shown in FIG. 4, the first bulging strip 161 has a groove shape when viewed from one side, and as shown in FIG. 5, has a protruding rib shape when viewed from the other side. Therefore, the first bulging strip 161 can be described as a hollow rib with an open side opposite to the protruding side. The second bulging strip 162 is also similar to the first bulging strip 161.

In the case of this embodiment, as shown in FIG. 2, the inclination θ1 of the first bulging line 161 and the inclination θ2 of the second bulging line 162 are each inclined at 45 degrees or approximately 45 degrees. Moreover, the direction of inclination is a direction rotated by a predetermined angle (45 degrees in the case of this embodiment) clockwise when viewed from the front side with respect to a radial direction centered on the winding shaft 122. In this way, by arranging the first bulging strip 161 and the second bulging strip 162 so as to be inclined in the same direction when viewed from the front side (also in the same direction when viewed from the rear side), the back and forth movement of the diaphragm 130 is controlled. As a result, the directions in which the up roll portion 151 and the down roll portion 152 twist around the winding shaft 122 are reversed. Here, "tilting in the same direction" means that both the inclination θ1 of the first bulging line 161 and the inclination θ2 of the second bulging line 162 are 0 degrees when the clockwise direction seen from the front side is the positive direction. This means a case where <θ1<90 degrees, 0 degrees<θ2<90 degrees, or a case where 0 degrees>θ1>−90 degrees, 0 degrees>θ2>−90 degrees. Note that "tilting in the opposite direction" means 0 degrees < θ 1 < 90 degrees, 0 degrees > θ 2 > -90 degrees, or 0 degrees > θ 1 > when clockwise as seen from the front side is the positive direction. -90 degrees, meaning the case where 0 degrees < θ2 < 90 degrees.

The first bulging strip 161 provided on the up-roll portion 151 is open on the front side and protrudes toward the rear side in a closed state. The second bulging strip 162 provided on the down roll portion 152 protrudes toward the front side and is open at the rear side. That is, the hollow first bulging strip is opened to the convex surface that is the bulging side (front side) surface of the up roll part 151 and the convex surface that is the bulging side (rear side) surface of the down roll part 152. 161 and a hollow second bulging strip 162 are provided, respectively. In addition, a first bulging strip 161 and a second bulging strip are provided in the concave surface of the up roll portion 151 that is the surface on the recess side (rear side) and in the concave surface that is the surface on the recess side (front side) of the down roll portion 152. Each strip 162 is provided in a protruding manner. The number of first bulging stripes 161 provided on the up roll portion 151 and the number of second bulging strips 162 provided on the down roll portion 152 are the same.

The thickness of the first bulging strip 161 and the second bulging strip 162 is equivalent to the thickness of other parts of the up roll portion 151 and the down roll portion 152. The first bulging strip 161 and the second bulging strip 162 extend linearly, and have a U-shaped cross-section in a plane perpendicular to the extending direction.

According to the above electroacoustic transducer 100, the up-roll portion 151 and the down-roll portion 152 are each provided with a bulging strip, so that the structural strength is low even though the entire edge 150 is wide. Each of them functions as a so-called tangential edge that suppresses the occurrence of resonance. Further, by combining the up roll portion 151 and the down roll portion 152, it is possible to equalize the amount of air removed at the edge 150 due to the vibration of the diaphragm 130, thereby suppressing the occurrence of secondary distortion.

In addition to the above effects, the inclination of the first bulging line 161 provided on the up roll part 151 and the inclination of the second bulging line 162 of the down roll part 152 are made to be in the same direction when viewed from the front side. Accordingly, the torsion occurring in the up-roll portion 151 and the torsion occurring in the down-roll portion 152 are generated in opposite directions, canceling out the torsion, and suppressing the occurrence of the phenomenon in which the diaphragm 130 is twisted and vibrates. . Therefore, it is possible to prevent the coil 120 from coming into contact with the magnetic circuit 110 and improve the frequency characteristics of the generated sound.

Note that the present disclosure is not limited to the above embodiments. For example, other embodiments of the present disclosure may be implemented by arbitrarily combining the components described in this specification or by excluding some of the components. Further, the present disclosure also includes modifications obtained by making various modifications to the above-described embodiments that a person skilled in the art can think of without departing from the gist of the present disclosure, that is, the meaning indicated by the words described in the claims. It will be done.

For example, a case has been described in which the first bulging strip 161 is arranged so as to protrude from the concave surface of the up roll part 151, and the second bulging strip 162 is arranged so as to protrude from the concave surface of the down roll part 152. 6, the first bulging strip 161 may be arranged so as to protrude from the convex surface of the up roll part 151, and the second bulging strip 162 may be arranged so as to protrude from the convex surface of the down roll part 152. do not have.

Further, as shown in FIG. 7, the first bulging strip 161 is arranged so as to protrude from the concave surface of the up roll part 151, and the second bulging strip 162 is arranged so as to protrude from the convex surface of the down roll part 152. Alternatively, the first bulging strip 161 may be arranged so as to protrude from the convex surface of the up roll section 151, and the second bulging strip 162 may be arranged so as to protrude from the concave surface of the down roll section 152. do not have. In this case, as shown in FIG. 8, the first bulging strip 161 and the second bulging strip 162 are arranged so that the inclinations are different from each other in a plan view from the front side. Thereby, the twist of the up roll portion 151 and the twist of the down roll portion 152 can be reversed. That is, the protruding directions of the first bulging line 161 and the second bulging line 162 are different (see FIGS. 1 and 6), and the inclination of the first bulging line 161 and the direction In the first case, the inclinations of the two bulging strips 162 are the same (see FIG. 2), and the first bulging strip 161 and the second bulging strip 162 have the same protruding direction (see FIG. 7); The inclination of the first bulging line 161 and the inclination of the second bulging line 162 with respect to the radial direction centered on the winding shaft 122 are set in different directions (see FIG. 8). In both cases, the twisting of the up-roll portion 151 and the twisting of the down-roll portion 152 can be reversed.

Further, the inclination of the first bulging line 161 and the inclination of the second bulging line 162 with respect to the radial direction centering on the winding shaft 122 do not have to be at the same angle.

Furthermore, in the plan view, the first bulging line 161 and the second bulging line 162 have been described as extending linearly, but the first bulging line 161 and the second bulging line 162 are It may be curved in plan view, such as a gentle S-shape.

Further, in the case of the present embodiment, a speaker that generates sound is illustrated as the electroacoustic transducer 100, but the electroacoustic transducer 100 converts acoustic air vibrations into electrical signals that are changes in electrical quantity. It does not matter if it is a microphone to be converted.

Furthermore, the edge 150 may include an up-roll portion 151 on the outside and a down-roll portion 152 on the inside. The edge 150 may include a plurality of pairs of up roll portions 151 and down roll portions 152.

Note that the number of first bulging stripes 161 provided on the up roll portion 151 and the number of second bulging strips 162 provided on the down roll portion 152 may be different. However, the design may be easier if the number is the same.

The electroacoustic transducer according to the present disclosure can be applied to audiovisual equipment including televisions, electronic equipment such as computers and smartphones, and even mobile objects such as automobiles.

100 Electroacoustic transducer 110 Magnetic circuit 111 Magnet 112 Top plate 113 Yoke 114 Magnetic gap 120 Coil 121 Bobbin 122 Winding shaft 130 Diaphragm 131 Diaphragm hole 132 Cap 140 Frame 141 Edge 142 Holding portion 143 Connecting portion 150 Edge 151 Up roll Part 152 Down roll part 153 First mounting part 154 Second mounting part 161 First bulging strip 162 Second bulging strip 170 Damper

Claims

magnetic circuit,
a coil disposed in the magnetic gap of the magnetic circuit;
a diaphragm to which the coil is connected;
a frame holding the magnetic circuit;
an edge connecting the diaphragm and the frame,
The edge is
an up-roll portion that curves to protrude toward the front side, which is one side in the vibration direction of the diaphragm;
a down roll part that is concentrically connected to the up roll part and curved so as to protrude toward the rear side, which is the other side in the vibration direction;
The up-roll portion is provided with a plurality of linear first bulging strips that bulge toward either one of the front and back directions,
The down roll portion is provided with a plurality of linear second bulging strips that bulge toward either one of the front and back directions,
When the protruding directions of the first bulging strip and the second bulging strip are different, the first bulging strip and the second bulging strip are different from each other in a radial direction centered on the winding axis of the coil. When the first bulging line and the second bulging line are tilted in the same direction, and the protruding direction of the first bulging line and the second bulging line is the same, the first bulging line and the second bulging line are oriented in a radial direction centered on the winding axis. An electroacoustic transducer whose rows tilt in different directions.
The first bulging strip provided on the up roll portion protrudes toward the rear side,
The second bulging strip provided on the down roll portion protrudes toward the front side,
The electroacoustic transducer according to claim 1, wherein the inclination of the first bulging strip and the inclination of the second bulging strip with respect to a radial direction centering on the winding axis are the same.
The electroacoustic transducer according to claim 1 or 2, wherein the number of the first bulging stripes and the number of the second bulging stripes are the same.
The electroacoustic transducer according to claim 1 or 2, wherein the shape of the first bulging strip and the shape of the second bulging strip are equivalent.