JP3863884B2 - Speaker system - Google Patents

Description

  The present invention relates to a speaker system, and more particularly to a speaker system that generates sound waves by a driving force in a rotational direction.

  One of the most common acoustic transducers (speaker systems) that convert sound signals into sound waves is an electrodynamic speaker system that includes a magnet and a voice coil. In this type of speaker system, the volume on the front side is changed by the vibration of the diaphragm, and this is converted into a change in sound pressure to generate sound waves.

  Apart from this, a speaker system has also been proposed in which the vibration plate is forcedly vibrated by its driving force to generate sound waves while reversing the rotation of the electrodynamic motor in the forward and reverse directions. Such a speaker system is particularly suitable for generating sound waves with high output in a low frequency band.

  However, the speaker system using the motor as described above converts the rotational driving force of the motor into a reciprocating driving force on a straight line, and the diaphragm is vibrated by the reciprocating driving force. Therefore, energy loss is large. Moreover, the linearity in conversion from an audio signal to a sound wave is impaired. That is, the distortion is large.

  An object of the present invention is to provide a speaker system that can generate a sound wave by utilizing the rotational driving force of a motor without converting it into a linear reciprocating motion.

In order to solve the above-described problems, a speaker system according to the present invention is a speaker system including a volume variable unit, a first rotation driving unit, and a second rotation driving unit, and the volume variable unit includes a first member and a first member. and a second member, which is said first member is rotatably supported around a rotation center axis and the said second member is rotatably supported about a rotation axis, the said first member By displacing in the circumferential direction relative to the second member, the volume on the front side of the volume variable portion changes, and the first rotation driving means centers the first member on the rotation center axis . And the second rotation driving means rotates the second member around the rotation center axis , thereby increasing or decreasing the volume on the front side of the volume variable section to generate sound waves. In order to solve the above problems, another speaker system according to the present invention is a speaker system including a volume variable portion and a first rotation driving means, wherein the volume variable portion includes a first member and a second member. The first member is supported so as to be rotatable about a rotation center axis, and the first member is displaced relative to the second member in the circumferential direction, whereby the volume is variable. The volume on the front side of the part changes, and the first rotation driving means rotates the first member about the rotation center axis , thereby increasing or decreasing the volume on the front side of the volume variable part to generate sound waves. One member of the first member and the second member has an opening, and the other member has a blocking portion that closes the opening. In order to solve the above-described problem, still another speaker system according to the present invention is a speaker system including a volume variable unit and a first rotation driving unit, and the volume variable unit includes a first member and a second member. And the first member is supported so as to be rotatable about the rotation center axis, and the first member is displaced in the circumferential direction relative to the second member, whereby the volume front side of the volume of the variable portion is changed, said first rotation driving means is said first member, by rotating about the said rotation axis, to increase or decrease the front side of the volume of said volume varying section waves One member of the first member and the second member has an opening, and the other member has a closing part that closes the opening, and the vicinity of the edge of the opening and the peripheral part of the closing part A flexible edge portion is interposed between the vicinity and the closed portion due to deformation of the edge portion. Becomes displaceable in a predetermined range with respect to the opening, the passive radiator is constituted by a said closure portion and said edge portion. In order to solve the above-described problem, still another speaker system according to the present invention is a speaker system including a volume variable unit and a first rotation driving unit, and the volume variable unit includes a first member and a second member. And the first member is supported so as to be rotatable about the rotation center axis, and the first member is displaced in the circumferential direction relative to the second member, whereby the volume The volume on the front side of the variable portion changes, and the first rotation driving means rotates the first member around the rotation center axis to increase or decrease the volume on the front side of the volume variable portion. The first rotation driving means is a first motor, and the first motor is a first ultrasonic motor.

  According to the speaker system of the present application, since the sound wave can be generated without converting the rotational driving force of the motor into a linear reciprocating motion, the energy loss is small and the linearity in sound reproduction is not easily lost. .

The speaker system according to the present invention is a speaker system comprising a volume variable portion, a first rotation drive means, and a second rotation drive means, wherein the volume variable portion has a first member and a second member, and the said first member is rotatably supported around a rotation center axis and the said second member is rotatably supported about a rotation axis, the said first member relative to said second member by displacing the relative circumferential direction, the front side of the volume change of said volume varying section, said first rotation driving means to said first member, is rotated around the said rotation axis, said The two-rotation driving means rotates the second member around the rotation center axis , thereby increasing or decreasing the volume on the front side of the volume variable portion to generate sound waves. According to this configuration, the rotational driving force is converted into acoustic energy without being converted into a linear reciprocating driving force. Further, the volume variable portion can be driven and controlled more precisely by the second rotation driving means.
In the speaker system, the rotation center axis of the first member and the rotation center axis of the second member may be coaxial.

  The speaker system may be configured such that the first member rotates only in one direction and the second member rotates only in the same direction as the first member. According to such a configuration, the rotation driving means is not reversed, and therefore, the speed discontinuity at the time of reversal is not adversely affected.

  In the speaker system, the first member may be rotated while changing a rotation speed.

  In the speaker system, the second rotation driving means may be a second motor. Furthermore, it is desirable that the second motor is a second ultrasonic motor in terms of output efficiency, ease of control, and phase roll-off.

  In the speaker system, the second member may be attached to the rotation shaft of the second motor.

Further, another speaker system according to the present invention is a speaker system including a volume variable portion and a first rotation driving means, wherein the volume variable portion includes a first member and a second member, The first member is supported so as to be rotatable about the rotation center axis, and the first member is displaced in the circumferential direction relative to the second member. There varies, said first rotation driving means is said first member, by rotating about the said rotation axis, to generate acoustic waves by increasing or decreasing the volume of the front side of said volume varying section, said first One member of the member and the second member has an opening, and the other member has a blocking portion that closes the opening. According to this configuration, the rotational driving force is converted into acoustic energy without being converted into a linear reciprocating driving force.

  In the speaker system, the opening may face in the circumferential direction.

  Further, in the speaker system, the closing portion may be a sliding portion that slides in the entrance / exit direction from the opening.

  Further, in the speaker system, a flexible edge portion is interposed between the vicinity of the edge of the opening and the vicinity of the peripheral edge of the closing portion, and the closing portion with respect to the opening is deformed by the deformation of the edge portion. It is preferable to be configured to be displaceable within a predetermined range in the circumferential direction because the movement of the closed portion can be relatively freely performed while maintaining airtightness around the closed portion.

Further, another speaker system according to the present invention is a speaker system including a volume variable portion and a first rotation driving means, wherein the volume variable portion includes a first member and a second member, The first member is supported so as to be rotatable about a rotation center axis, and the first member is displaced in the circumferential direction relative to the second member, whereby the front side of the volume variable portion is The volume changes, and the first rotation driving means rotates the first member about the rotation center axis , thereby increasing or decreasing the volume on the front side of the volume variable portion to generate sound waves, and One member and one member of the second member have an opening, and the other member has a closing part that closes the opening, and is possible between the vicinity of the edge of the opening and the vicinity of the peripheral part of the closing part. A flexible edge portion is interposed, and deformation of the edge portion causes the closed portion to have a predetermined range with respect to the opening. In displaceable and becomes passive radiator is constituted by a said closure portion and said edge portion. According to this configuration, the rotational driving force is converted into acoustic energy without being converted into a linear reciprocating driving force. In this way, a simple configuration with a small number of parts can be achieved.

  The speaker system may include a restricting unit that restricts a displacement direction of the closing portion with respect to the one member only to a predetermined direction.

  In the above speaker system, the restricting means may restrict the displacement direction of the closing portion only in the circumferential direction.

  In the speaker system, the opening may be directed in the circumferential direction.

  In the speaker system, the first member may be configured to rotate only in one direction. According to such a configuration, the rotation driving means is not reversed, and therefore, the speed discontinuity at the time of reversal is not adversely affected.

  In the speaker system, the first member may rotate while increasing or decreasing the rotation speed around a predetermined rotation speed.

  Further, in the above speaker system, when a plurality of the openings are formed side by side in the circumferential direction and the plurality of openings are closed by the plurality of closed portions, the vibration area is increased instead of the size of the speaker system. Can do.

  In the speaker system, the first rotation driving means may be a first motor.

  Further, if the first motor is a first ultrasonic motor, it is desirable in terms of output efficiency, ease of control, and phase roll-off.

Further, another speaker system according to the present invention is a speaker system including a volume variable portion and a first rotation driving means, wherein the volume variable portion includes a first member and a second member, The first member is supported so as to be rotatable about a rotation center axis, and the first member is displaced in the circumferential direction relative to the second member, whereby the front side of the volume variable portion is The volume changes, and the first rotation driving means rotates the first member about the rotation center axis, thereby increasing or decreasing the volume on the front side of the volume variable portion to generate sound waves, and One rotation driving means is a first motor, and the first motor is a first ultrasonic motor.
In the speaker system, the first member may be attached to the rotation shaft of the first motor.

  In the speaker system described above, an angle formed by the base surface and at least one of the rising surfaces rising from the base surface may be an obtuse angle in the circumferential cross section of the volume variable portion.

  A speaker system S1 according to an embodiment of the present invention will be described with reference to FIGS.

  The speaker system S1 described here is mainly composed of a volume variable unit V1 and a first ultrasonic motor M1 serving as a first rotation driving unit.

  1A and 1B are views showing the variable volume portion V1, in which FIG. 1A is a plan view and FIG. 1B is a front view thereof. FIG. 2 is a perspective view of the variable volume portion V1.

  The volume variable portion V1 is mainly configured by combining a synthetic resin tongue member B1 as a first member and a synthetic resin cover member D1 as a second member. Reference symbol C in the figure is a central axis common to the cover member D1 and the tongue member B1 of the first ultrasonic motor M1. The reason why the name “tongue member” is given to the member B1 is that, as will be described later, this member behaves as if the tongue enters and exits from the mouth. Here, the member driven by the first ultrasonic motor M1 is positioned as the first member.

  As can be understood from FIGS. 1 and 2, the cover member D <b> 1 has a substantially annular peripheral edge 11. In addition, a substantially cylindrical central protruding portion 12 protruding upward is formed at the central portion. Six cover chambers 13 are radially formed in the cover member D <b> 1 from the central protrusion 12 to the peripheral edge 11. The six storage chambers 13 are arranged at intervals of 60 degrees. The storage chamber 13 protrudes upward from the base 14 of the cover member D1, and a space is formed therein.

  The tongue member B1 has a disk-shaped base 21. Further, the tongue member B1 has six projecting portions 22 projecting upward from the base 21. The six protrusions 22 are radially formed on the base 21 at intervals of 60 degrees.

  The shapes of both the cover member D1 and the tongue member B1 are substantially rotationally symmetric. The “rotationally symmetric” mentioned here refers to a shape that, when rotated by M times (360 / N) degrees around the central axis, is a shape that is surjective to the shape itself. Here, “N” is a predetermined integer of 2 or more, and “M” is an arbitrary integer. In the speaker system S1 of the present embodiment, “N” is “6”.

  The volume variable portion V1 is configured by combining the cover member D1 and the tongue member B1 thus configured.

  A base 21 of the tongue member B1 is fitted into the peripheral edge 11 of the cover member D1. The cover member accommodating chamber 13 has an opening that allows communication between the internal space and the external space. The shape of the opening is substantially rectangular, and the normal line of the opening surface substantially coincides with the circumferential direction. The protrusion 22 of the tongue member B1 is fitted into this opening. The protruding portion 22 functions as a blocking portion that closes the opening of the storage chamber 13.

  FIG. 3 is a longitudinal sectional view of the speaker system S1 attached to the case 30 and the case 30 attached to the baffle plate 35. The cross section of the volume variable portion V1 in this figure corresponds to the cross sectional view taken along the line AA in FIG.

  From FIG. 3, it can be more easily understood that the opening 15 of the cover member D1 is covered with the protruding portion 22 of the tongue member B1. Note that a gap is necessary around the protrusion 22, but this gap should be narrow. Moreover, it is preferable to close this gap with a fluid such as grease having low viscosity. This is because airtightness can be maintained and the movement of the tongue member B1 is not hindered so much.

  The front side of the variable volume portion V1 means the upper side in FIGS. 2 and 3 with respect to the peripheral portion 11 of the cover member D1 and the base 21 of the tongue member B1.

  The case 30 includes a substantially cylindrical side portion 31, a substantially circular bottom portion 32 that closes the bottom thereof, and a flange portion 33 that protrudes radially outward from the upper end of the side portion 31. A plurality of holes 34 are formed in the bottom 32.

  A case 30 is fitted in a circular hole formed in the baffle plate 35. The case 30 is attached to the baffle plate 35 by screwing the flange portion 33 to the baffle plate 35.

  Although the speaker system S1 is arranged in the case 30, the cover member D1 is integrated with the side portion 31 of the case 30 in the embodiment shown in FIG. Therefore, the cover member D1 cannot move.

  The first ultrasonic motor M1 is fixed to the bottom 32 of the case 30, and the central portion of the tongue member B1 is fixed to the tip of the rotating shaft 41 of the first ultrasonic motor M1. In addition, the code | symbol 42 in a figure is a coupling member for attaching the tongue member B1 to the rotating shaft 41. FIG. When the first ultrasonic motor M1 is driven, the tongue member B1 moves. That is, the protrusion 22 of the tongue member B1 is displaced in the circumferential direction. The protruding portion 22 also functions as a sliding portion that slides inside the opening 15. The first ultrasonic motor M1 is driven so as to repeatedly reverse the rotation direction while changing the rotation speed.

  FIG. 4 is a diagram illustrating a combination of the cross section taken along line BB in FIG. 1 and the side view of the first ultrasonic motor M1. As understood from this figure, when the first ultrasonic motor M1 is driven so as to repeat the reversal of the rotation direction, the protrusion 22 repeatedly increases and decreases the amount of protrusion from the opening 15 of the cover member D1. In other words, the tongue member B1 vibrates in the circumferential direction with respect to the cover member D1. Then, the volume on the front side of the volume variable portion V1 is repeatedly increased and decreased. As a result, the speaker system S1 generates sound waves. In addition, arrow R1 in FIG. 4 shows the moving direction of the protrusion part 22 which reciprocates in the circumferential direction.

  In the simplest example, when the rotational speed of the first ultrasonic motor M1 changes sinusoidally, the angle of the rotation shaft 41 also changes sinusoidally. Then, the volume on the front side of the volume variable portion V1 also changes in a substantially sinusoidal manner, so that the speaker system S1 generates a sinusoidal sound wave.

  If the change in the rotation speed of the first ultrasonic motor M1 is made more complicated, more complicated sound waves can be generated. When the rotational speed of the first ultrasonic motor M1 is modulated by a predetermined modulation method based on the audio signal, a sound wave corresponding to the audio signal can be generated.

  The speaker system S1 uses the first ultrasonic motor M1 as its drive source. Therefore, the conversion efficiency in electroacoustic conversion can be made very high. Further, since the change in the volume on the front side of the volume variable portion V1 is proportional to the change in the rotation angle of the first ultrasonic motor M1, the audio signal that is the basis for the rotation speed modulation of the first ultrasonic motor M1 and the volume In relation to the change in the volume on the front side of the variable portion V1, the phase roll-off on the frequency axis can be minimized.

  It is also possible to use an electrodynamic motor in place of the first ultrasonic motor M1.

  In the speaker system S1, the tongue member B1 is directly connected to the rotating shaft 41 of the first ultrasonic motor M1, but it is not always necessary to connect it directly. For example, a gear mechanism or a belt transmission mechanism may be interposed between the tongue member B1 and the rotation shaft 41 of the first ultrasonic motor M1, and the two may be indirectly coupled. Moreover, you may make it change a rotating shaft direction by comprising the gear mechanism in this case with a bevel gear.

  In the speaker system S1, a plurality of openings 15 are formed in the cover member D1, and a plurality of protrusions 22 are formed in the tongue member B1. Thus, by providing a plurality of openings 15 and protrusions 22, the vibration area of the speaker system S1 can be made larger than the area of the volume variable part V1. This means that a small speaker system can be constructed instead of the volume that can be generated. Note that the vibration area referred to here substantially corresponds to the total area of the six openings 15. Further, the area of the volume variable portion V1 substantially matches the area of a circle whose diameter matches the outer diameter of the cover member D1.

  The speaker system S1 according to the embodiment of the present invention has been described above with reference to FIGS.

  Next, a speaker system S2 according to another embodiment of the present invention will be described mainly with reference to FIG.

  FIG. 5 is a longitudinal sectional view of the speaker system S2 in a state where the speaker system S2 is attached to a cylindrical case 50 having substantially the same shape as the case 30 shown in FIG.

  The speaker system S2 is mainly configured by a volume variable unit V2 and a first ultrasonic motor M1 serving as a first rotation driving unit.

  The plan view of the volume variable portion V2 is substantially the same as that shown in FIG. 1A, the front view of the volume variable portion V2 is substantially the same as that shown in FIG. 1B, and the volume variable portion V2 The oblique view is substantially the same as that shown in FIG.

  Also in the speaker system S2, the volume variable portion V2 is mainly configured by combining the cover member D2 and the tongue member B2. The structure of the cover member D2 is substantially the same as the cover member D1 in the first embodiment, and the structure of the tongue member B2 is substantially the same as the tongue member B1 in the first embodiment.

  Also in the speaker system S2, the protruding portion 22 of the tongue member B2 functions as a closing portion that closes the opening 15 of the cover member D2, and also functions as a sliding portion that slides inside the opening 15. The tongue member B2 is displaced in the circumferential direction relative to the cover member D2. As a result, the volume on the front side of the volume variable portion V2 increases or decreases, and thereby the speaker system S2 generates sound waves.

  As described above, the speaker system S2 is common to the speaker system S1 of the first embodiment in many respects. However, the speaker system S2 is different from the speaker system S1 of the first embodiment in the following points.

  That is, the speaker system S2 is configured such that the tongue member B2 cannot move. The tongue member B <b> 2 is fixed to the bottom portion 32 of the case 50 via the fixing column 43. In addition, since the base | substrate 25 of the tongue member B2 has comprised the annular | circular shape, the tongue member B2 is comprised by the one member. That is, the six protrusions 22 are formed on one tongue member B2.

  On the other hand, the center portion of the cover member D2 is fixed to the tip of the rotating shaft 41 of the first ultrasonic motor M1. Therefore, the cover member D2 is reciprocated in the circumferential direction. In this sense, in the speaker system S2, the cover member D2 is the first member of the volume variable portion V2. The tongue member B2 is the second member of the volume variable portion V2.

  The peripheral edge 17 of the cover member D2 projects outward in the radial direction. This protruding portion is loosely fitted in an annular groove formed on the inner wall of the side portion 37 of the case 50. Therefore, the cover member D2 is rotatably supported with respect to the case 50.

  When the first ultrasonic motor M1 is driven to repeat the reversal of the rotation direction, the cover member D2 reciprocates in the circumferential direction, and the protrusion 22 repeatedly increases and decreases the amount of protrusion from the opening 15 of the cover member D2. . Then, the volume on the front side of the volume variable portion V2 repeatedly increases and decreases. As a result, the speaker system S2 generates sound waves.

  The speaker system S2 as one embodiment of the present invention has been described above mainly with reference to FIG.

  Next, a speaker system S3 according to still another embodiment of the present invention will be described with reference to FIGS.

  The speaker system S3 described here is mainly configured by a volume variable unit V3 and a first ultrasonic motor M1 serving as a first rotation driving unit.

  6A and 6B are diagrams showing the volume variable portion V3, where FIG. 6A is a plan view and FIG. 6B is a front view thereof. FIG. 7 is a perspective view of the volume variable portion V3.

  The volume variable portion V3 is mainly configured by combining a synthetic resin main member P3 as a first member and a closing member Q3 as a second member. The shape of the blocking member Q3 is a substantially rectangular plate shape. A symbol C in the drawing is a central axis common to the main member P3, the closing member Q3, and the first ultrasonic motor M1.

  As can be understood from FIGS. 6 and 7, the main member P3 has a structure similar to the cover member D1 in the speaker system S1 of the first embodiment. That is, the main member P3 has a substantially circular outline in plan view. Further, a substantially cylindrical central projecting portion 62 projecting upward is formed at the central portion, and six chambers 63 are formed radially from the central projecting portion 62 to the periphery. Six chambers 63 are arranged at intervals of 60 degrees. The chamber 63 protrudes upward from the base 64 of the main member P3, and a space is formed therein. The shape of the main member P3 is substantially rotationally symmetric.

  The chamber 63 of the main member P has an opening that allows communication between the internal space and the external space. The shape of the opening is substantially rectangular, and the normal line of the opening surface substantially coincides with the circumferential direction. Each of the six openings is closed by the closing member Q3. In addition, it is not essential that the normal line of the opening surface substantially coincides with the circumferential direction. The direction of the opening may be appropriately determined according to the design conditions and the like.

  In order to airtightly close the opening by the closing member Q3 and to allow the closing member Q3 to be displaced within a certain range with respect to the main member P3, the vicinity of the edge of the opening and the vicinity of the peripheral edge of the closing member Q3 It is effective to interpose a flexible edge portion between them.

  In this embodiment, the outer dimension of the closing member Q3 is smaller than the dimension of the opening. In order to attach the closing member Q3 to the opening, a member for closing a gap formed around the closing member Q3 is necessary. In the speaker system S3, this gap is closed by the edge member 71.

  The edge member 71 is configured in the same manner as the free edge disposed between the cone diaphragm and the frame of the electrodynamic speaker system. That is, the shape is a rectangular ring shape, and it is made of a flexible material having a certain degree of airtightness, such as urethane foam, rubber, leather, and a cloth coated with a mesh. Since the edge member 71 has flexibility, the closing member Q3 can be displaced in the circumferential direction relative to the main member P3. Airtightness is also maintained. The closing member Q3 can be displaced within a predetermined range in the circumferential direction around the position of the opening.

  FIG. 8 is a diagram in which the cross section taken along the line BB in FIG. 6 and the side view of the first ultrasonic motor M1 are described in combination.

  From this figure, it can be more easily understood that the closing member Q3 is attached to the opening 15 of the main member P3 via the edge member 71 and the opening 15 is closed.

  The central portion of the main member P3 is fixed to the tip of the rotating shaft 41 of the first ultrasonic motor M1 fixed to the bottom of the case.

  Further, the closing member Q3 is fixed to the bottom of the case or the like via the fixed column 44.

  When the first ultrasonic motor M1 is driven, the main member P3 moves. That is, the chamber 63 of the main member P3 is displaced in the circumferential direction. The first ultrasonic motor M1 is driven so as to repeatedly reverse the rotation direction while changing the rotation speed.

  Since the closing member Q3 is fixed so as not to move, when the first ultrasonic motor M1 is driven so as to repeat reversal of the rotation direction, the main member P3 is relatively moved with respect to the closing member Q3. Vibrates in the circumferential direction. Then, the volume on the front side of the volume variable portion V3 is repeatedly increased and decreased. As a result, the speaker system S3 generates sound waves. In addition, arrow R2 in FIG. 8 shows the moving direction of the chamber 63 that reciprocates in the circumferential direction.

  In the speaker system S3 described above, the gap around the closing member Q3 is closed by the edge member 71 made of a flexible material. Therefore, it is preferable also in the point which keeps airtightness and also in the point which makes the main member P3 easy to displace with respect to the closure member Q3.

  It is also possible to adopt a structure in which the closing member Q3 and the edge member 71 are integrated, that is, a structure such as a cone diaphragm having a fixed edge.

  In the speaker system S3 described above, the closing member Q3 is fixed and the main member P3 is displaced in the circumferential direction. However, the main member P3 is fixed and the closing member Q3 is displaced in the circumferential direction. Good. In this case, the closing member Q3 is the first member of the variable volume portion V3, and the main member P3 is the second member of the variable volume portion V3.

  The speaker system S3 as one embodiment of the present invention has been described above with reference to FIGS.

  Next, a speaker system S4 according to still another embodiment of the present invention will be described mainly with reference to FIGS.

  FIG. 9 is a diagram showing the structure of the speaker system S4 in the same manner as shown in FIG.

  The speaker system S4 is mainly configured by a volume variable unit V4, a first ultrasonic motor M1 that is a first rotation driving means, and a second ultrasonic motor M2 that is a second rotation driving means.

  The plan view of the volume variable portion V4 is substantially the same as that shown in FIG. 6A, and the front view of the volume variable portion V4 is substantially the same as that shown in FIG. 6B, and the volume variable portion V4. The oblique view is substantially the same as that shown in FIG.

  Also in the speaker system S4, the volume variable portion V4 is mainly configured by combining a main member P4 as a first member and a closing member Q4 as a second member. The structure of the main member P4 is substantially the same as the main member P3 in the third embodiment, and the structure of the closing member Q4 is substantially the same as the closing member Q3 in the third embodiment. Also in the speaker system S4, a rectangular opening 15 is formed in the main member P4, and a closing member Q4 is attached so as to close the opening 15. A gap formed around the closing member Q is closed by the edge member 71. The structure of the edge member 71 in the speaker system S4 is the same as the structure of the edge member 71 in the speaker system S3 of the third embodiment.

  Also in the speaker system S4, the main member P4 is displaced in the circumferential direction relative to the closing member Q4, and the volume on the front side of the volume variable portion V4 is increased or decreased to generate sound waves.

  As described above, the speaker system S4 is common to the speaker system S3 of the third embodiment in many respects. However, the speaker system S4 is different from the speaker system S3 of the third embodiment in the following points.

  That is, in the speaker system S4, the closing member Q4 is driven by the second ultrasonic motor M2. As a result, the closing member Q4 also moves in the circumferential direction.

  As can be understood from FIG. 9, the rotating shaft 41 of the first ultrasonic motor M1 and the rotating shaft 45 of the second ultrasonic motor M2 are arranged coaxially. The rotating shaft 45 of the second ultrasonic motor M2 is formed in a cylindrical shape. That is, a central hole is formed. The rotation shaft 41 of the first ultrasonic motor M1 passes through this center hole.

  In the first ultrasonic motor M1, the tip of the rotation shaft 41 is fixed to the center of the main member P4 so as to rotate the main member P4.

  The rotation shaft 45 of the second ultrasonic motor M2 is fixed to the closing member Q4 via the support member 46 in order to rotate the closing member Q4.

  The first ultrasonic motor M1 is fixed to the bottom of the case or the like, and the second ultrasonic motor M2 is fixed thereon via a coupling member 47.

  Since it is configured in this manner, the rotation center axis of the main member P4 and the rotation center axis of the closing member Q4 exist on the same axis.

  Various methods are conceivable as to how to control the ultrasonic motors M1 and M2 of the speaker system S4 configured as described above to generate sound waves, but the following rotation control is preferable. That is, in both ultrasonic motors M1 and M2, sound waves are generated by controlling so that the rotation axis does not reverse. Arrows R3 and R4 in FIG. 9 indicate the moving directions of the chamber 63 and the closing member Q4 of the main member P4 when the rotations of the ultrasonic motors M1 and M2 are controlled as described above.

  For example, the second ultrasonic motor M2 is rotated at a constant speed, and the first ultrasonic motor M1 is rotated so that the rotational speed increases or decreases around the rotational speed. Then, in the first ultrasonic motor M1, the rotation shaft 41 is prevented from being reversed. The rotation direction of the first ultrasonic motor M1 and the rotation direction of the second ultrasonic motor M2 are not opposite to each other.

  Thus, the reason why the rotation shafts 41 and 45 are controlled not to be reversed in both the ultrasonic motors M1 and M2 is as follows. That is, generally, when the motor is reversed, the correspondence with the rotation control signal is likely to be impaired. For example, even if a rotation control signal that reverses the rotation by a smooth change in the rotation speed is given, the rotation speed of the motor may become discontinuous during the reversal. In such a situation, the sound wave to be generated is distorted.

  Therefore, it is preferable to always maintain the rotation directions of the ultrasonic motors M1 and M2 in a constant direction, that is, to prevent inversion.

  FIG. 10 is a diagram illustrating an example of controlling the rotations of the ultrasonic motors M1 and M2 as described above. FIG. 10A illustrates the rotation angles of the rotation shafts 41 and 45 of the ultrasonic motors M1 and M2. It is a relationship diagram of the rotation angle with respect to time, with the time being represented with the horizontal axis. Both the horizontal and vertical axes are linear axes.

  In FIG. 10A, the solid line is a relationship line related to the first ultrasonic motor M1, and the broken line is a relationship line related to the second ultrasonic motor M2.

  As understood from this figure, the broken line is a straight line having a certain inclination. That is, the second ultrasonic motor M2 rotates at a constant speed.

  On the other hand, the solid line is a curve that moves up and down around the broken line. The slope of this real curve is always 0 or more. That is, the first ultrasonic motor M1 varies the rotation speed but does not reverse it.

  FIG. 10B is a relationship diagram of the relative angle with respect to time, with the angle obtained by subtracting the angle of the broken line from the angle of the solid line in FIG. Both the horizontal and vertical axes are linear axes. This relative angle is an angle of the rotation shaft 41 of the first ultrasonic motor M1 relative to the rotation shaft 45 of the second ultrasonic motor M2.

  As understood from FIG. 10 (b), the angle of the rotating shaft 41 of the first ultrasonic motor M1 is relatively sinusoidally relative to the rotating shaft 45 of the second ultrasonic motor M2. It is displaced.

  Therefore, the volume on the front side of the volume variable portion V4 of the speaker system S4 repeatedly increases and decreases. As a result, the speaker system S4 generates sound waves.

  FIG. 11 is a diagram showing another example for controlling the rotation of the ultrasonic motors M1 and M2 so as not to reverse, and (a) shows the rotation angles of the rotation shafts 41 and 45 of the ultrasonic motors M1 and M2. Is a relationship diagram of rotation angle with respect to time, with the vertical axis representing time and the horizontal axis representing time. Both the horizontal and vertical axes are linear axes.

  In FIG. 11A, a solid line is a relationship line related to the first ultrasonic motor M1, and a broken line is a relationship line related to the second ultrasonic motor M2.

  As understood from this figure, the solid line has a constant slope in the periods J2 and J4, but forms a curve in the periods J1 and J3. On the other hand, the broken line has a constant slope in the periods J1 and J3, but forms a curve in the periods J2 and J4.

  That is, the first ultrasonic motor M1 rotates at a constant speed during the periods J2 and J4, and varies the rotation speed during the periods J1 and J3. The second ultrasonic motor M2 rotates at a constant speed during the periods J1 and J3, and the rotation speed varies during the periods J2 and J4.

  As described above, although both the ultrasonic motors M1 and M2 change the rotation speed in a certain period, the slopes of both the solid line and the broken line in FIG. 11A are always 0 or more. That is, the ultrasonic motors M1 and M2 change the rotation speed but do not reverse them.

  FIG. 11B is a relationship diagram of the relative angle with respect to time, with the angle obtained by subtracting the angle of the broken line from the angle of the solid line in FIG. Both the horizontal and vertical axes are linear axes.

  As understood from FIG. 11B, the angle of the rotation shaft 41 of the first ultrasonic motor M1 is relatively sinusoidally relative to the rotation shaft 45 of the second ultrasonic motor M2. It is displaced.

  Therefore, the volume on the front side of the volume variable portion V4 of the speaker system S4 repeatedly increases and decreases. As a result, the speaker system S4 generates sound waves.

  The speaker system S4 according to one embodiment of the present invention has been described above mainly with reference to FIGS.

  Next, a speaker system S5 according to still another embodiment of the present invention will be described mainly with reference to FIG.

  FIG. 12 is a diagram showing the structure of the speaker system S5 in the same manner as shown in FIGS.

  The speaker system S5 is mainly configured by a volume variable unit V5 and a first ultrasonic motor M1 serving as a first rotation driving unit.

  The plan view of the volume variable portion V5 is substantially the same as that shown in FIG. 6A, the front view of the volume variable portion V5 is substantially the same as that shown in FIG. 6B, and the volume variable portion V5. The oblique view is substantially the same as that shown in FIG.

  Also in the speaker system S5, the volume variable portion V5 is mainly configured by combining a main member P5 as a first member and a closing member Q5 as a second member. The structure of the main member P5 is substantially the same as the main member P3 in the third embodiment.

  As will be described later, the closing member Q5 is configured to function as a passive radiator in combination with the edge member 71.

  Also in the speaker stem S5, a chamber 63 is formed in the main member P5, and a rectangular opening 15 is formed in the chamber 63. In addition, a rectangular plate-like closing member Q5 is attached so as to close the opening 15. A gap formed around the closing member Q5 is closed by the edge member 71. The structure of the edge member 71 in the speaker system S5 is the same as the structure of the edge member 71 in the speaker system S3 of the third embodiment.

  Also in the speaker system S5, the main member P5 is displaced in the circumferential direction relative to the closing member Q5, and the sound volume is generated by increasing or decreasing the volume on the front side of the volume variable portion V5.

  Thus, the speaker system S5 is common to the speaker system S3 of the third embodiment in many respects. However, the speaker system S5 is different from the speaker system S3 of the third embodiment in the following points.

  That is, in the speaker system S5, the closing member Q5 is supported by the main member P5 via the edge member 71, but is not supported by other members (members other than the main member P).

  As can be understood from FIG. 12, the first ultrasonic motor M1 is fixed to the bottom of the case or the like, and the tip of the rotating shaft 41 is positioned at the center of the main member P5 in order to rotate the main member P5. It is fixed.

  Further, the closing member Q5 constitutes a passive radiator in combination with the edge member 71. The resonance frequency (of the passive radiator) is configured to be lower than the reproduction lower limit frequency of the speaker system S5. For example, if the reproduction lower limit frequency of the speaker system S5 is 40 Hz, the passive radiator is configured so that the resonance frequency of the passive radiator is 10 Hz.

  Various methods are conceivable as to how the ultrasonic motor M1 of the speaker system S5 thus configured is controlled to generate sound waves, but the following rotation control is preferable. That is, in the ultrasonic motor M1, sound waves are generated by controlling so that the rotation shaft 41 is not reversed. An arrow R5 in FIG. 12 indicates the moving direction of the chamber 63 when the rotation of the ultrasonic motor M1 is controlled as described above.

  The reason why it is preferable to control the rotation of the rotation shaft 41 of the ultrasonic motor M1 is as described above.

  Further, particularly in the speaker system S5, it is preferable to change the rotation speed of the first ultrasonic motor M1 so that the rotation speed increases or decreases around a predetermined rotation speed. The reason is that when the rotation of the first ultrasonic motor M1 is controlled in this way, the closing member Q5 rotates close to a constant speed rotation by the predetermined rotation speed.

  That is, the reason why the rotational speed of the first ultrasonic motor M1 is changed is that air is vibrated to generate sound waves. Therefore, the slowest change in the rotational speed of the first ultrasonic motor M1 is a rotational speed change due to modulation at the reproduction lower limit frequency of the speaker system S5.

  On the other hand, as described above, the resonance frequency of the passive radiator configured by the combination of the closing member Q5 and the edge member 71 is lower than the reproduction lower limit frequency of the speaker system S5.

  Therefore, even if the rotational speed of the first ultrasonic motor M1 is changed so that the rotational speed increases or decreases around the predetermined rotational speed, the closing member Q5 does not follow the speed change, and the predetermined rotational speed It is considered to rotate at a substantially constant speed.

  That is, it is considered that the main member P5 and the closing member Q5 of the speaker system S5 exhibit the same behavior as when the speaker system S4 of Example 4 is driven by the drive control method as shown in FIG.

  The speaker system S5 has a small number of parts and a simple structure, and can generate sound waves with less distortion by appropriate drive control of the first ultrasonic motor M1.

  Note that it is not always necessary to control the ultrasonic motor M1 so that the rotation shaft 41 is not reversed. For example, the main member P may be driven while repeating the reversal of the rotation shaft 41 around the rotation speed of 0 (degrees / second) (that is, the stopped state). In this case, it is considered that the passive radiator is almost stopped.

  Although not shown in FIG. 12, it is also effective to provide a restricting means for restricting the moving direction of the closing member Q5 relative to the main member P5 to a predetermined direction.

  FIG. 13 is a diagram showing the configuration of this limiting means. The restricting means includes a rod 81 attached to the back side of the closing member Q5 and a cylindrical guide 82 attached to the inner wall of the chamber 63 of the main member P5. A rod 81 is inserted into the guide 82, and the moving direction of the rod 81 is regulated by the guide 82. When such a restricting means is provided, the displacement of the closing member Q5 relative to the main member P5 has only a circumferential component. Therefore, for example, the slight vibration in the direction orthogonal to the circumferential direction can be prevented, and the movement of the closing member Q5 becomes smooth. Note that the direction defined by the limiting means is not limited to the circumferential direction. The direction in which the moving direction of the closing member Q5 is determined by the restricting means may be appropriately determined according to the design conditions of the speaker system S5.

  Moreover, not only Example 5 but all the above-mentioned Examples (Examples 1 to 5) can be modified as follows. In other words, in the circumferential cross section of the volume variable portion, if the angle formed by the base surface and the rising surface rising from the base surface is an obtuse angle, it is advantageous for reproduction at a higher frequency. This is because the directivity of the speaker system and, consequently, the output efficiency are more likely to be affected by the direction in which the surface of the vibrating member is directed at a higher frequency. Note that the “circumferential cross section” of the volume variable portion referred to here is a cross section that appears when the volume variable portion is cut by a cylindrical surface along the circumferential direction. For example, FIGS. 4, 8, 9, and 12 show a circumferential cross section of the variable volume portion.

  FIG. 14 is a circumferential sectional view of the volume variable portion V5 showing a modification of the embodiment shown in FIG. The volume variable portion V5 is mainly composed of a main member P5 and a closing member Q5. In the volume variable portion V5, the board surface 90 of the main member P5 serves as a base surface. As can be understood from FIG. 14, the outer side surface 91 of the chamber 63 is a surface rising from the base surface (board surface) 90. Further, the outer side surface 92 of the closing member Q5 is also a surface rising from the base surface (board surface) 90.

  As shown in FIG. 14, the angle α formed by the outer side surface 91 and the base surface (board surface) 90 is an obtuse angle. Further, the angle β formed by the outer surface 92 and the base surface (board surface) 90 is also an obtuse angle.

  In this embodiment, the closing member Q5 has a rotational motion close to a constant speed, and the main member P5 has a rotational motion with a change in speed, so that the outer surface 91 of the chamber 63 substantially functions as a diaphragm. Therefore, it is more effective to make the formed angle α obtuse than to make the formed angle β obtuse. That is, when the angle α formed is made larger, the state is similar to that of the diaphragm vibrating in the front-rear direction (vertical direction in the figure). Therefore, sound waves can be generated efficiently at a high frequency.

  In the volume variable portion, the angle formed by the base surface and all rising surfaces rising from the base surface need not be obtuse. When there are a plurality of rising surfaces rising from the basal plane, an effect is obtained by making the angle formed by at least one of the surfaces and the basal plane an obtuse angle.

  As described above, it is effective to make the angle formed by the rising surface and the basal plane on the surface of the member that performs a rotational motion with a speed change an obtuse angle.

  The angle formed at this time may be an obtuse angle, but is preferably 120 degrees or more, and more preferably 135 degrees or more.

  The speaker system S5 as one embodiment of the present invention has been described above mainly with reference to FIG.

  By using the speaker system of the present application, it is possible to reduce energy loss and make it difficult to impair linearity in sound reproduction, and thus can be used in the technical field of electroacoustics.

It is a figure which shows a volume variable part, (a) is the top view, (b) is the front view. It is a perspective view of a volume variable part. It is a longitudinal section in the state where a speaker system was attached to a case and a case was attached to a baffle board. It is the figure described combining the BB arrow cross section of FIG. 1, and the side view of a 1st ultrasonic motor. It is a longitudinal section of a speaker system in the state where a speaker system was attached to a case. It is a figure which shows a volume variable part, (a) is the top view, (b) is the front view. It is a perspective view of a volume variable part. It is the figure described combining the BB arrow directional cross section of FIG. 6, and the side view of a 1st ultrasonic motor. It is the figure which showed the structure of the speaker system by the same manner as shown in FIG. It is a figure which shows an example of rotation of ultrasonic motor M1, M2, (a) is the relationship of the rotation angle with respect to time which represented the rotation angle of each rotating shaft of the ultrasonic motor on the vertical axis | shaft, and time was shown on the horizontal axis. (B) is a relationship diagram of the relative angle with respect to time, with the angle obtained by subtracting the angle of the broken line from the angle of the solid line in (a) on the vertical axis and the time on the horizontal axis. It is a figure which shows the other example when controlling so that rotation of an ultrasonic motor may not be reversed, (a) represented the rotation angle of each rotating shaft of an ultrasonic motor on the vertical axis | shaft, and expressed time on the horizontal axis. (B) shows the relative angle with respect to time, with the vertical axis representing the angle obtained by subtracting the angle of the broken line from the solid line angle in (a) and the horizontal axis representing time. It is a relationship diagram. It is the figure which showed the structure of the speaker system by the style similar to having shown in FIG. 8, FIG. It is a figure which shows the structure of a limiting means. FIG. 13 is a circumferential cross-sectional view of a volume variable portion showing a modification of the embodiment shown in FIG. 12.

Explanation of symbols

S1, S2, S3, S4, S5 Speaker system V1, V2, V3, V4, V5 Volume variable part B1, B2 Tongue member D1, D2 Cover member P3, P4, P5 Main member Q3, Q4, Q5 Closure member M1 First Ultrasonic motor M2 Second ultrasonic motor

Claims (23)

A speaker system comprising a volume variable portion, a first rotation drive means, and a second rotation drive means,
The volume variable portion has a first member and a second member,
The first member is supported so as to be rotatable about a rotation center axis;
The second member is supported so as to be rotatable about a rotation center axis;
When the first member is displaced in the circumferential direction relative to the second member, the volume on the front side of the volume variable portion changes,
Said first rotation driving means is said first member, is rotated around the said rotation axis, said second rotation driving means to said second member, by rotating about the said rotation axis, said A speaker system that generates sound waves by increasing or decreasing the volume on the front side of the volume variable section.   The speaker system according to claim 1, wherein the rotation center axis of the first member and the rotation center axis of the second member are coaxial. The first member rotates only in one direction;
The speaker system according to claim 1 or 2, wherein the second member rotates only in the same direction as the first member. The first member rotates while changing the rotation speed;
The speaker system according to any one of claims 1 to 3, wherein the second member rotates at a constant speed.   The speaker system according to claim 1, wherein the second rotation driving unit is a second motor.   The speaker system according to claim 5, wherein the second motor is a second ultrasonic motor.   The speaker system according to claim 5 or 6, wherein the second member is attached to a rotation shaft of the second motor. A speaker system comprising a volume variable section and first rotation driving means,
The volume variable portion has a first member and a second member,
The first member is supported so as to be rotatable about a rotation center axis;
When the first member is displaced in the circumferential direction relative to the second member, the volume on the front side of the volume variable portion changes,
The first rotation driving means rotates the first member about the rotation center axis , thereby increasing or decreasing the volume on the front side of the volume variable portion to generate sound waves,
One member of the first member and the second member has an opening,
A speaker system, wherein the other member has a closing portion that closes the opening.   The speaker system according to claim 8, wherein the opening faces in a circumferential direction.   The speaker system according to claim 8 or 9, wherein the closing portion is a sliding portion that slides in the direction of entering and exiting from the opening. A flexible edge portion is interposed between the vicinity of the edge of the opening and the vicinity of the peripheral edge of the closed portion,
The speaker system according to claim 8 or 9, wherein the closed portion can be displaced within a predetermined range with respect to the opening by deformation of the edge portion. A speaker system comprising a volume variable section and first rotation driving means,
The volume variable portion has a first member and a second member,
The first member is supported so as to be rotatable about a rotation center axis;
When the first member is displaced in the circumferential direction relative to the second member, the volume on the front side of the volume variable portion changes,
The first rotation driving means rotates the first member about the rotation center axis , thereby increasing or decreasing the volume on the front side of the volume variable portion to generate sound waves,
One member of the first member and the second member has an opening,
The other member has a blocking portion that closes the opening,
A flexible edge portion is interposed between the vicinity of the edge of the opening and the vicinity of the peripheral edge of the closed portion,
Due to the deformation of the edge portion, the closed portion can be displaced within a predetermined range with respect to the opening,
A speaker system in which a passive radiator is configured by the closed portion and the edge portion.   The speaker system according to claim 12, further comprising a restricting unit that restricts a displacement direction of the closing portion relative to the one member to a predetermined direction.   The speaker system according to claim 13, wherein the restricting means restricts a displacement direction of the blocking portion only in a circumferential direction.   The speaker system according to any one of claims 12 to 14, wherein the opening faces in a circumferential direction.   The speaker system according to any one of claims 12 to 15, wherein the first member rotates only in one direction.   The speaker system according to claim 16, wherein the first member rotates while increasing or decreasing the rotation speed around a predetermined rotation speed. A plurality of the openings are formed side by side in the circumferential direction,
The speaker system according to any one of claims 8 to 17, wherein the plurality of openings are closed by the plurality of blocking portions.   The speaker system according to any one of claims 1 to 18, wherein the first rotation driving means is a first motor.   The speaker system according to claim 19, wherein the first motor is a first ultrasonic motor.   A speaker system comprising a volume variable section and first rotation driving means,
  The volume variable portion has a first member and a second member,
  The first member is supported so as to be rotatable about a rotation center axis;
  When the first member is displaced in the circumferential direction relative to the second member, the volume on the front side of the volume variable portion changes,
  The first rotation driving means rotates the first member about the rotation center axis, thereby increasing or decreasing the volume on the front side of the volume variable portion to generate sound waves,
  The first rotation driving means is a first motor;
  A speaker system, wherein the first motor is a first ultrasonic motor. The speaker system according to any one of claims 19 to 21, wherein the first member is attached to a rotation shaft of the first motor. The speaker system according to any one of claims 1 to 22 , wherein an angle formed by a base surface and at least one of rising surfaces rising from the base surface is an obtuse angle in a circumferential cross section of the volume variable portion. .

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