JP6401399B2 - Vibration prevention device for audio equipment - Google Patents

Description

  The present invention is an apparatus for preventing an impact or vibration applied from the outside in an audio equipment from affecting an original sound signal, and more specifically, an arm that supports a turntable and a record needle of a record player that is an analog audio equipment. The present invention relates to a device that prevents external impact and vibration to a part that rotates and rotates around a shaft like a base.

  For acoustic equipment that reproduces recorded sound, vibration that is different from the original sound applied from outside, for example, impact when objects or people collide, or acoustic equipment from the ground when vehicles or people pass nearby If there is a vibration transmitted from the speaker to the sound equipment through the air (howling), the external vibration, whether analog or digital, will affect the reproduction of the original sound, even if there is a difference in the degree of influence. It is known to give

  Especially in analog audio equipment, a record player that reproduces the vibration of the original sound by tracing the groove of the record board that recorded the vibration shape of the original sound as it is with a needle, the external vibration applied to the original sound reproduction Since it has a direct influence, many means for preventing vibration applied from the outside have been considered.

  First of all, there is a means to make the casing of the record player, which is a restraining body, and the turntable, which is a rotating body, large and heavy so that the influence of external vibration is relatively small. Compared with up, the external vibration reduction effect was not enough.

  On the other hand, many techniques have been proposed in which external vibration transmitted is directly damped by a combination of flexible structures of construction materials (see, for example, Patent Document 1).

  In addition, a technique has been proposed in which an air layer is interposed between the outside (bearing) and the rotating body (shaft) so that vibration transmitted from the outside to the shaft and vibration generated on the shaft are not attenuated but blocked. (For example, refer to Patent Document 2).

JP 2000-222799 A No. 7-29719

  As mentioned above, in the case of an acoustic device such as a record player that greatly affects the reproduction of the original sound, increasing the weight of the rotating body (mainly the turntable) stabilizes the rotation and also affects the external vibration. Although it becomes relatively small, if the size of the rotation shaft is not increased accordingly, the rotation of the rotating body will occur and a force in the tilt direction to the shaft will be applied. It was also necessary to increase the diameter.

  However, there is a contradiction that the rotation resistance of the rotating shaft increases and the sliding resistance at the time of rotation increases and smooth rotation cannot be obtained, and external vibration transmitted through the rotating shaft as the diameter of the rotating shaft increases. There was also a problem of becoming larger.

  In addition, mechanical bearings are used to obtain a smooth rotation of the rotating shaft. However, conventional bearings serve to prevent shaft shake by receiving the weight of a rotating body such as a turntable and supporting it from the side. Since the rotating shaft was supported in a state where gravity or pressing force was applied, there was a problem that external vibration was directly transmitted to the shaft.

  Therefore, in addition to the weight of the rotating body and the increase in the diameter of the rotating shaft, it is possible to apply a vibration damping technique as in Patent Document 1 or to apply a non-contact type bearing such as an air bearing as in Patent Document 2. It was considered ideal.

  By the way, for example, rubber, urethane, and the like using attenuation characteristics have been conventionally used in various places for acoustic equipment. However, if the structure is too flexible, it leads to allowing movements other than the rotation of the rotating body, and when the structure as in Patent Document 1 is applied to a record player, unnecessary movement of the turntable directly affects the reproduction of the original sound. Therefore, it is difficult to balance the structure.

  In addition, in the case of a record that reproduces a music signal by moving the record needle along the groove of the record board, the record board and the record needle move relative to each other, external vibration to the record board side (turntable side) Even if the sound is attenuated, excellent vibrations cannot be reproduced unless the vibration transmitted to the record needle through the tone arm is cut off.

  On the other hand, as an air bearing as exemplified in Patent Document 2, a dynamic pressure air bearing that creates an air layer between a rotating shaft and a bearing by using an air flow caused by the rotation of the shaft, and a forced air flow. There is a hydrostatic air bearing that creates an air layer between the rotating shaft and the bearing, but dynamic pressure air bearings require high-speed rotation of the shaft, and low-speed rotation (33-45 rpm) such as a turntable of a record player Not suitable.

  Even in the case of a hydrostatic air bearing, a high-pressure air pump is indispensable in order to lift the shaft completely from the bearing with air, which is expensive to apply to a record player. Also, because the shaft is not in mechanical contact with the bearing, external vibrations are not easily transmitted, but there is a risk of pulsations that cause the shafts to shake regularly. For players, unwanted vibrations directly affect the reproduction of the original sound.

  In order to prevent this unnecessary pulsation, it is necessary to close the gap between the shaft and the bearing by processing in micron units, and as a record player, the manufacturing cost tends to be very high, and if too much gap is packed, eventually There is a contradiction that it is not possible to completely prevent the transmission of external vibrations, and it is still impossible to reproduce the original sound accurately unless the vibrations transmitted through the tone arm are also prevented, so a sufficient effect cannot be expected for the high cost. There was a problem.

  As described above, even if the turntable is weighted to reduce the influence of external vibration or to stabilize the rotation by inertia, for example, if it is supported by only one thin rotating shaft, for example, one heavy object Like the bell that was hung on the ground, there was a fatal problem that the sound resonated greatly with external input (vibration / impact).

  The present invention solves the problems as described above, can prevent the influence of external vibration at a relatively low cost, and can obtain a stable rotation of the rotating body having a large diameter shaft, It is an object of the present invention to provide an audio device such as a record player that can reproduce a faithful original sound.

In order to solve the above-mentioned problems, the invention of claim 1 has a rotating body that can rotate with respect to the base substrate about an axis in the vertical direction on the upper surface of the base substrate. In audio equipment that affects the playback of
The rotating body has a disk shape, the upper surface of the base substrate and the lower surface of the rotating body facing each other are smooth surfaces, the base substrate has a through hole from the upper surface to the lower surface, and one end of the air tube is formed at the lower end of the through hole. And connecting the upper end portion of the through hole and the outer diameter portion of the bearing, and a cylindrical body provided with a plurality of holes for internal and external conduction in the vicinity of the upper end portion is formed in a cylindrical shape at the center of the lower surface of the rotating body. The upper end opening of the body is fixed so as to be sealed at the lower surface of the rotating body, the cylindrical body is rotatably held at the bearing inner diameter portion, and an air pump that sends compressed air to the other end of the air tube is connected, A vibration preventing apparatus for an acoustic device, wherein compressed air is sent from an air pump through an air tube into a through hole of a base substrate.

  In the present invention, an acoustic device in which vibration applied from the outside affects the reproduction of the original sound means that in most acoustic devices, the external vibration has an adverse effect. In particular, the record needle traces the groove on the record board. In the case of a record player in which the relative movement (vibration) between the record board and the record hand generated in the above is directly reproduced sound, the influence is great, and it is most suitable for application of the present invention.

  It does not matter whether the rotating body is rotated or rotated or stopped at the time of sound reproduction at a portion that rotates or rotates as necessary at the time of music reproduction or at the preparation stage. In the structure of the present invention, since the air is sent from the air tube to the bearing of the base substrate, the air flowing into the gap between the upper surface of the base substrate and the lower surface of the rotating body supports and rotates the weight of the rotating body. The bearing is devoted to the role of holding the rotating shaft in a fixed position, and the bearing part can support the rotation with an ideal point contact, and the rotation of the rotating shaft with low sliding resistance can be obtained, and the gravity In addition, it can be expected to reduce external vibration at the ideal point contact bearing part where no pressing force is applied.

  In addition, since the upper surface of the base substrate and the lower surface of the rotating body facing each other are smooth surfaces, the gap can be kept to a minimum, and air flows from the center of the rotation shaft to the periphery within the minimum gap and the rotating body is heavy. As a result, the rotation of the rotating body does not occur, and a stable rotation such as using a rotating shaft whose diameter is the size of the rotating body is obtained.

  The invention according to claim 2 is the record player according to claim 1, wherein the audio device plays the music of the analog record board, and the rotating body is a turntable that holds the analog record board on the upper surface. This is a vibration preventing device for an acoustic device.

  If the present invention is applied to a turntable of a record player, the influence of stable rotation and external vibration during playback of the record board can be reduced.

  A third aspect of the present invention is the sound recording apparatus according to the first aspect, wherein the acoustic device is a record player that reproduces music of an analog record board, and the rotating body is an arm base of a tone arm. This is a device for preventing vibration of equipment.

  If the present invention is applied to the rotation of the arm base that supports the bottom of the tone arm of the record player, it is possible to reduce the influence of external vibration transmitted to the record hands during the reproduction of the record board.

  According to a fourth aspect of the present invention, in the first aspect of the present invention, the audio device is a record player that plays back the music of an analog record board, and the rotating body is an arm base of a turntable and a tone arm. This is a vibration preventing device for an acoustic device.

  The invention of claim 5 is the invention of claim 3 or 4, wherein a reflection type photo interrupter is installed upward below a transparent glass base substrate, and a reflection plate is provided below the tone arm. Provided, the reflection type photo interrupter captures the reflected light from the reflection plate, and senses the position of the tone arm in the direction of rotation of the arm base when reproducing the record board, and the tilt position in the vertical direction, The vibration preventing device for an acoustic device according to the first aspect, wherein rotation and stop of the turntable are controlled based on the position information.

  According to the above configuration, the rotation of the turntable can be controlled by the position of the tone arm (position and tilt position in the rotation direction). Can stop rotation.

  The rotating body is more stable when it has mass, and the influence of external vibration is relatively small, but if it is too heavy, the shaft body must have a large diameter accordingly, and the cost will be increased. As described above, in the structure of the first aspect of the present invention, the weight of the rotating body is supported by the air flowing into the gap between the upper surface of the base substrate and the lower surface of the rotating body by sending air from the air tube to the bearing of the base substrate. Since it is rotated, the mechanical bearing can only support the rotation with an ideal point contact with only the role of holding the rotation axis in a fixed position, and the rotation of the rotation axis with low sliding resistance is stable. Is obtained.

  In addition, the bearing part is in an ideal point contact state where no gravity or pressing force is applied. Therefore, like a conventional bearing, it makes contact without any play due to the gravity of a heavy rotating body or the pressing force caused by shaft shake. Thus, external vibrations are not directly transmitted, and an effect of reducing external vibrations at the bearing portion can be expected, and an effect equivalent to that of a completely non-contact type air bearing that is expensive can be obtained at low cost.

  Furthermore, since air flows from the center of the rotating shaft to the periphery to support the heavy rotating body on the entire lower surface, the rotating body does not cause rotation blur, and the rotating shaft having the diameter of the rotating body is used. Stable rotation is obtained, and unnecessary resonance is not generated such that a bell suspended at one point continues to resonate due to an external impact.

  In addition, since the rotating body is lifted by air, the bearing of the shaft body is not burdened by the weight of the rotating body. Friction loss can be reduced, smooth rotation (rotation) can be obtained, and it has a positive effect when playing music.

  On the other hand, since the weight of the rotating body can be made larger than that of the conventional one by using a bearing equivalent to the conventional one, the rotation speed can be stabilized by increasing the weight of the rotating body.

  According to the invention of claim 2, if the rotating body is a turntable on which a record board on which music or the like is recorded is placed, vibration applied from the outside is not transmitted to the turntable. You can avoid giving.

  According to the invention of claim 3, since the rotating body is an arm base for holding the tone arm of the record player, vibration applied from the outside is not transmitted from the arm base to the pickup such as a record needle through the tone arm. It is possible to prevent adverse effects due to external vibrations and the like during music reproduction.

  According to the invention of claim 4, in particular, a record player that reproduces the original sound by relative movement (vibration) between the record board and the record hands uses both the turntable of claim 2 and the arm base of claim 3. Since the external vibration to both the groove of the record board and the record hands can be cut off, excellent original sound reproduction not affected by the external vibration is made.

  According to the invention of claim 5, since the turntable can be automatically started to rotate by the operation of the tone arm accompanying the pickup movement to the record board, and the turntable can be automatically stopped by the end of the record board reproduction. , Operation at the time of record board playback becomes easy.

The record player which concerns on this invention is shown, (A) is a top view, (B) is a front view. It is an arrow front view of the cross section along the II-II dashed-dotted line of FIG. It is a top view of a base substrate. It is an enlarged plan view near the through hole of the base substrate. It is an enlarged plan view near the expanding part of the air tube. The attachment to the base substrate of an air tube is shown in order, (A) is a partial cross section side view, (B) is a cross section side view. Other embodiment of the attachment to the base substrate of an air tube is shown in order, (A) is a partial cross section side view, (B) is a cross section side view. It is a front view which shows the structure of the shaft body vicinity of a turntable. The attachment to the base substrate of a turntable is shown in order, (A) is a partial cross section front view, (B) is a cross section front view. An arm base is shown, (A) is a top view, (B) is a bottom view. The attachment of the tone arm to the base substrate is shown in order, (A) is a partial sectional front view, and (B) is a sectional front view. It is a top view which shows the reproduction | regeneration state of the record board of a record player. It is a cross-sectional front view of the shaft body vicinity of the turntable at the time of reproduction | regeneration of a record board. It is a partially cutaway side view which shows other embodiment of the record player which concerns on this invention. It is a top view same as the above.

Hereinafter, an example of an audio device of the present invention will be described with reference to the accompanying drawings.
FIG. 1 shows an example of a record player 1 to which the present invention is applied, in which (A) is a plan view and (B) is a front view. FIG. 2 is a front view showing a cross section taken along the line II-II in FIG.

  The main components constituting the record player 1 are a housing 2, a turntable 3 on which a record board is placed and rotated on the top surface of the housing 2, and a tone arm 5 that holds a pickup 4 such as a record needle. Consists of.

  The casing 2 has a rectangular shape and is provided with legs 2a made of vibration-proof insulators at the four corners of the lower surface. The casing 2 is made of a material that is not easily affected by external vibrations or howling from speakers. In particular, wood, resin, etc. are used, but in this embodiment, heavy stone is used.

  On the upper surface of the housing 2, although not shown in order to drive the turntable 3, for example, a recess for storing a driving means by a motor is provided. It is preferable to employ a belt drive system or a thread drive using cotton thread or silk thread as the drive system because vibrations such as cocking of the motor are not directly applied to the turntable 3.

  On the upper side of the housing 2, there is placed a flat base substrate 6 having substantially the same area as the upper surface of the housing 2 and at least the upper surface being a smooth surface. In the case of this embodiment, in order to fill a gap between the case 2 having stone irregularities and the smooth base substrate 6, to secure a storage space for the air tube 7 described in detail later, In order not to directly transmit the applied external vibration to the base substrate 6, a gap is provided between the upper surface of the housing 2 and the lower surface of the base substrate 6, and the space between them is filled with silicon rubber 8.

  The smoothness of the upper surface of the base substrate 6 is better as the smoothness is higher. However, since the manufacturing costs such as polishing and measurement are infinite, the present invention is applied to the turntable 3 of the record player 1. The smoothness of the surface glass surface of the mirror may be sufficient.

  Then, it is possible to use glass itself used for a mirror surface. In this embodiment, a flat glass plate having a thickness of 5 mm is used as the base substrate 6. Of course, other materials such as stones and other hard materials may be polished and mirror finished, but using marble or the like costs 10 to 100 times the cost of glass. Is more preferable from the viewpoint of cost reduction. Note that a so-called float type plate glass that floats on a molten metal having a specific gravity higher than that of glass and forms a plate shape is preferably mirror-like without being polished.

  On the upper surface of the base substrate 6, the turntable 3 that rotates while holding the record board on the upper surface is rotatably held by any driving means (not shown) such as a belt drive using a motor or a yarn drive. Has been.

  Further, the reference of the rotation of the tone arm 5 for allowing the pickup 4 to move in the lateral direction, which is generated when the pickup 4 is moved on the record board or the groove on the record board is traced by the reproduction of the record board, is used. An arm base 9 serving as a shaft is also rotatably held.

  The material of the turntable 3 and the arm base 9 is not particularly limited, and various materials such as glass and marble can be used. However, as in the case of the base substrate 6, it is preferable to use glass from the viewpoint of cost. The smoothness of the lower surface of the table 3 or the arm base 3 may be as smooth as the surface glass surface of the mirror, like the upper surface of the base substrate 6.

  As an example, the turntable 3 in this embodiment is made of glass with a diameter of 296 mm and a thickness of 10 mm and has a weight of 1690 g. However, there are heavier high-grade record breakers, and the present invention also includes those. Can be applied.

  Next, the structure near the rotation axis of the turntable 3 will be described in detail with reference to FIGS. 3 to 9. First, the position of the axis of the base substrate 6 on which the turntable 3 rotates is as shown in FIG. Further, a round through hole 10 is formed through the base substrate 6 from the upper surface to the lower surface, and a bearing 11 has an outer diameter at the upper end of the through hole 10 as shown in FIGS. The portion is provided by being fixed to the inner wall surface of the through hole 10 with an adhesive.

  As an example of this embodiment, the through hole 10 has a diameter of 8 mm, and the bearing 11 is a ball bearing type having an outer diameter of 8 mm, an inner diameter of 5 mm, and a vertical dimension of 2.5 mm.

  Moreover, the expanded part 7a which opened and opened the one end side of the air tube 7 as shown in FIG. 5 is connected with the lower end part of the through-hole 10, as shown in FIG. 6 (A), and FIG. As shown to B), it adhere | attaches with the lower surface of the base substrate 6 so that air may not leak around the expansion part 7a.

  The air tube 7 may be made of any material such as resin or metal as long as it is cylindrical and allows air to pass through. In this embodiment, an aluminum pipe having an outer diameter of 4 mm and an inner diameter of 3 mm was used.

  The air tube 7 passes through the portion of the silicon rubber 8 on the lower side of the base substrate 6 and is led out from the back side of the record player 1 as shown in FIG. 1 and FIG. Is connected to an air pump (not shown).

  An air pump (not shown) to which the other end of the air tube 7 is connected may have a pressure of about 12 to 15 Kpa (g), and when open, about 1000 cc / min to 3000 cc / min. Air pumps can be diverted and the cost is low.

  FIG. 7 shows another embodiment in which the air tube 7 is fixed to the through hole 10 portion of the base substrate 6 using the nipple 19 without providing the expanded portion 7a shown in FIG. is there.

  The nipple 19 used in this embodiment is a pipe having an outer diameter of 4 mm and an inner diameter of 3 mm. The upper end of the nipple 19 a contacts the lower surface of the base substrate 6, and the upper side of the ridge 19 a penetrates the base substrate 6. It has a convex portion 19b with a diameter of 8 mm that fits into the hole 10, and further, a bulging portion 19c with an outer diameter of 5 mm that prevents the air tube 7 from coming off is provided in the middle of the body, and the lower end is an air tube. 7 is rounded so that it can be easily fitted.

  As shown in FIG. 7 (A), the nipple 19 is fitted with the convex portion 19b of the nipple 19 from the lower end side of the through hole 10 of the base substrate 6 and fixed by appropriate means (epoxy adhesive or the like). As shown in FIG. 7B, the air tube 7 is fitted from the lower end side of the nipple 19 and is externally fitted until it reaches the flange portion 19a beyond the bulging portion 19c.

  When the air tube 7 is fixed in the embodiment of FIG. 7, the nipple 19 protrudes on the lower side of the base substrate 6, so that the portion is provided with a recessed cavity or the motor for the turntable 3. What is necessary is just to enter into the recessed part cavity for arrangement | positioning.

  FIG. 8 is a front view of a portion serving as a rotation axis of the turntable 3. Under the center spindle 12 serving as a rotation center by positioning the record board through the center hole of the record board, a cylindrical body is formed. A shaft body 13 is connected and fixed, and below that, an inner hollow cylindrical body 14 is fixed so that the upper end opening is sealed off by the lower surface of the shaft body 13. These center spindle 12, shaft body 13, cylinder All the shaped bodies 14 have a coaxial central axis.

  As an example, the center spindle 12 has a diameter of 7.2 mm and a vertical dimension of 12 mm, the shaft body 13 has a diameter of 8 mm, a vertical dimension of 9 mm, and the cylindrical body 14 has a diameter (outer diameter) of 5 mm and an inner diameter of 4 mm.

  In the vicinity of the upper end portion of the cylindrical body 14, a plurality of holes 14 a that conduct inward and outward in the lateral direction are provided, and the lower end portion of the cylindrical body 14 is in an open state. In the embodiment, the holes 14a have four holes in four directions or three holes with a regular interval of 1.5 mm in diameter. However, the number and size of the holes 14a are not particularly limited.

  As shown in FIG. 9 (A), the periphery of the shaft body 13 is fitted into a hole provided in the center of the turntable 3 and fixed and integrated with an adhesive 15 such as epoxy, and then the cylindrical body 14 is attached. The base plate 6 is fitted in a bearing 11 fixed in the through hole 10 and is rotatably held.

  The tone arm 5 holds the pickup 4 provided at the tip so as to be movable up and down and left and right, and various shapes are conceivable. In this embodiment, as shown in FIG. It has a trapezoidal shape with different front and rear widths, and is provided with a pickup 4 such as a record needle and a finger hook 16 used for moving the pickup 4 on the record board by hand at the narrow front end, A balance weight (not shown) is provided at the wide rear end, and an arm base 9 for rotating the tone arm for allowing lateral movement of the tone arm 5 is located near the wide rear end. To do.

  Next, the structure of the vicinity of the pivot axis of the arm base 9 will be described. First, after the through hole 10 is opened in the base substrate as shown in FIG. 3, the pivot portion of the arm base 9 shown in FIG. As with the turntable 3, the bearing 11 is fixed and the air tube 7 is connected. The connection structure of the air tube 7 is the same as that shown in FIGS. 5 to 7 for the turntable 3 described above, and detailed description thereof is omitted.

  10A and 10B show the arm base 9, in which FIG. 10A is a plan view and FIG. 10B is a bottom view. FIGS. 11A and 11B are front cross-sectional views illustrating the attachment state of the arm base 9 and the tone arm 5 to the base substrate 6 in order.

  The arm base 9 has a disk shape, and at least a lower surface thereof is a smooth surface like the turntable. As an example of the embodiment, the arm base 9 is made of glass having a thickness of 5 mm.

  Further, a hole having a diameter of 8 mm is provided at the center of the arm base 9, and a shaft body 13 having a cylindrical body 14 fixed to the lower surface is bonded and fixed to the hole. The structure of the shaft body 13 and the cylindrical body 14 is substantially the same as that shown in FIG. 8 when the turntable 6 is described, except that the center spindle 12 is omitted.

  However, the vertical dimension of the shaft body 13 is set to 5 mm in accordance with the thickness of the arm base 9. In addition, the structure (dimensions, hole 14a) of the cylindrical body 14 is the same as that shown in FIG.

  When this shaft body 13 is fitted into a hole (diameter 8 mm) opened through the arm base 9 and bonded with an epoxy adhesive or the like, as shown in FIGS. 10 (B), 11 (A) and 11 (B). In addition, the cylindrical body 14 protrudes from the center of the lower surface.

  As shown in FIGS. 10 (A), 11 (A) and 11 (B), the upper surface of the arm base 9 has a columnar shape extending in the vertical direction on both sides of the central shaft 13 and having a conical upper end. Two bow tapers 17 are erected.

  In this embodiment, as an example, the bow taper 17 has an upper end conical portion that continues to a column portion having a diameter of 8 mm at the lower portion and has a tapered shape of 50 °, and the height from the upper surface of the arm base 9 to the apex of the bow taper 17 is about 25 mm. Yes.

  In order to assemble the arm base 9 and the tone arm 5 to the base substrate 6, as shown in FIGS. 11A and 11B, the cylindrical shape of the lower surface of the arm base 9 is formed on the bearing 11 of the through hole 10 of the base substrate 6. The body 14 is fitted, and the tone arm 5 is placed on the two bow tapers 17 of the arm base 9.

  The mounting structure of the tone arm 5 to the arm base 9 is such that a short cylindrical round bow 18, 18 is attached to the lower surface of the tone arm 5 at a position corresponding to the two bow tapers 17, 17. The tone arm 5 is attached to the arm base 9 by positioning the conical depression 18 a over the top of the bow taper 17.

  In this embodiment, the round bow 18 has a diameter of 15 mm, the conical depression 18 a has a 100 °, and the tone arm 5 supported by the tops of the two bow tapers 17, 17 has the tops of the two bow tapers 17, 17. It rotates (swings) about the connecting line as a central axis, and this allows the pickup 4 in the vicinity of the front end of the tone arm 5 to move up and down.

  In addition, the tone arm 5 supported by two-point support at the tops of the two bow tapers 17 and 17 does not swing laterally about the length direction of the tone arm 5, so that the tone arm during playback of the record board Even if a horizontal swing is applied to the recording head 5, it is possible to suppress the record needle from swinging left and right and adversely affecting the reproduction of the original sound.

  Further, the balance weight (not shown) at the rear end of the tone arm 5 allows the needle pressure of the record needle of the pickup 4 to be adjusted appropriately, and the bow tapers 17 and 17 have a substantially front-rear balance of the weight of the tone arm 5. As a result, the vicinity of the shaft body 13 at the center of the arm base 9 is directly below the center of gravity of the tone arm 5, and no force that tilts the shaft acts on the shaft body 13, and the arm base 9 is rotated in a well-balanced manner. be able to.

  The record player 1, which is an audio device of the present invention, has the structure as described above. Next, a case where a record board is reproduced using the record player 1 will be described.

  As shown in FIG. 12, the record board R is placed on the turntable 3, and then air 20 is supplied to the vicinity of the shaft 13 of the turntable 3 and the arm base 9 through the air tube 7 by driving the air pump. Before and after that, the turntable 3 is rotated at a specified speed (33 + 1/3 rpm or 45 rpm) by a driving means such as a motor.

  Next, the pickup 4 is placed on the groove of the record board R on the turntable 3 while putting the finger on the finger hook 16 near the tip of the tone arm 5 and rotating the tone arm 5 about the axis of the arm base 9. When you drop the needle, the music starts playing.

  At this time, as shown in FIG. 13, in the vicinity of the rotation axis of the turntable 3, the air 20 supplied from the bottom surface of the base substrate 6 through the air tube 7 as shown by the arrow in the drawing is within the through hole 10 and the bottom surface of the cylindrical body 14. It exits from the upper hole 14a through the opening and is discharged to the outside through a gap between the upper surface of the base substrate 6 and the lower surface of the turntable 3 which are smooth surfaces.

  The gap between the base substrate 6 and the turntable 3 can be held to several μm to several tens of μm if the smoothness is high, but it is preferable to hold the gap between about 2 μm. Even if it is about several tens μm to 100 μm, an effect is produced to some extent. However, if the gap is narrow, the effect of floating the turntable 3 with the same amount of air (the amount of air blown by the air 20) is enhanced.

  Although the weight of the turntable 3 is 1680 g in this embodiment, it is supported by the air 20 flowing between the lower surface of the turntable 3 and the upper surface of the base substrate 6, and the above-described air pump (pressure 12) not shown in the gap of about 2 μm. It will float sufficiently with an air flow rate of about 15 Kpa (g), discharge rate at opening 1000 cc / min to 3000 cc / min).

  For example, the air (air 20) power is tremendous because the aircraft's weight of about 300 tons including the capacity of the airplane's jumbo jet can float with only the air force at a takeoff speed of 250 Km / h. Therefore, the turntable 3 of the present invention can also be applied to a heavyweight turntable of 14 kg or more by adjusting the clearance and the air pump discharge amount.

  Although the bearing 11 is ideally point-contacted with the shaft (cylindrical body 14), there is a play portion for rotation, and the bearing 11 itself has an ability to cut off vibration. However, the conventional one receives the weight of the turntable 3 at the contact portion between the bearing and the shaft during rotation and supports the tilt of the shaft from the lateral direction. Since the shaft was supported in a state in which external vibration was added, there was an inconvenience that external vibration was transmitted directly to the shaft.

  However, in the structure of the present invention, the air 20 is sent from the air tube 5 to the bearing 11 of the base substrate 6 so that the weight of the turntable 3 is reduced by the air 20 flowing into the gap between the upper surface of the base substrate 6 and the lower surface of the turntable 3. Since it is supported and rotated, the mechanical bearing 11 can devote itself to the role of holding the cylindrical body 14 in a fixed position, and the bearing 11 can support the rotation of the turntable 3 with an ideal point contact and has low sliding. It seems that stable rotation due to resistance can be obtained, and transmission of external vibration in the ideal point contact bearing 11 which is not subjected to gravity or pressing force can be reduced.

  Further, the air 20 passes between the smooth surfaces of the turntable 3 and the base substrate 6, so that the turntable 3 floats slightly, and the turntable 3 and the base substrate 6 are kept in a non-contact state. Therefore, most of the vibration applied from the outside, for example, the vibration transmitted from the ground to the housing 2 by the movement of a vehicle or a person or from the speaker to the housing 2 through the air (howling), is caused by the play of the bearing 11 and the base substrate 6. And the turntable 3 can be blocked by an air layer formed by air 20, so that external vibration is not applied to the record board R.

  Similarly, in the portion of the tone arm 5 as well, most of the vibration transmitted to the base substrate can be blocked by the play of the bearing 11 and the air layer formed by the air 20 between the base substrate 6 and the arm base 9. External vibration is not transmitted to the base 5 and the pickup 4 (record needle). Therefore, in the case of the record that reproduces the original sound by the relative movement of the record board and the record hand, the record player using the turntable and the arm base of the present invention can block both external vibrations to the record board R and the record hand. Therefore, excellent original sound reproduction that is not affected by external vibration is performed.

  As an external vibration isolation test, when playing the record board R with the record player 1 and striking the case 2 with force, the conventional record player adds a large impact sound to the playback sound. In severe cases, sound skipping due to movement of the record needle occurred, but in the record player 1 of the present invention, no impact sound or sound skipping occurred.

  Next, another embodiment of the record player according to the present invention will be described with reference to FIGS. The basic structure and operation of the case 2, the turntable 3, the pickup 4, the tone arm 5, the air tube 7, the arm base 9 and the like of the record player-1 in this embodiment are the same as those of the record player 1 in FIGS. The detailed description is omitted.

  First, in the case of this embodiment, the base substrate 6 is made of transparent glass, and a hollow portion is formed through the casing 2 at a predetermined position between the arm base 9 and the turntable 3, and a reflection type is provided here. The photo interrupter 21 is stored. In addition, in order to provide a cavity part in the housing | casing 2, it is preferable that the housing | casing 2 is made from concrete and the shaping of a cavity part is provided beforehand.

  The light-emitting and light-receiving portions of the reflective photointerrupter 21 are provided adjacent to each other on the same surface. The sensor unit 22 having the light-emitting unit and the light-receiving unit is installed upward, and is made of transparent glass from the light-emitting unit. While the light is irradiated upward through the base substrate 6, the light is reflected by the object, and the light receiving unit receives light again through the base substrate 6, the reflective photo interrupter 21 performs control to rotate the turntable 3. To do.

  A downward reflecting plate 23 is provided on the lower surface of the tone arm 5 near the arm base 9 on the pickup 4 side, and the pickup 4 is placed in the outermost groove of the record board R as shown in FIG. Between the tone arm 5s at the start position and the position immediately before the tone arm 5p at the end position of the reproduction where the pickup 4 is placed in the innermost endless groove of the record board R, the reflector 23 reflects the reflection. The tone arm 5 has a horizontally long shape so as to continuously face the sensor portion 22 of the photo interrupter 21.

  The configuration of the reflection type photo interrupter 21 and the reflection plate 23 is as described above. The control method of the reflection type photo interrupter 21 is that the pickup 5 of the tone arm 5 is at the reproduction position of the record board R, and the sensor unit 22 is When the light receiving unit receives light reflected by the reflecting plate 23 as opposed to the reflecting plate 23, the turntable 3 is controlled to rotate and maintain rotation.

  On the other hand, until the position of the tone arm 5 reaches the tone arm 5s at the solid line position or the reproduction start position in FIG. 15 or at the position of the tone arm 5p that has reached the reproduction end position of the record board R, the sensor unit 22 is used. Since there is no reflecting plate 23 directly above the light receiving portion, the light receiving portion does not receive the reflected light, so that the turntable 3 is not rotated.

  Even if the tone arm 5 is positioned on the record board R, the tone arm 5 is tilted with the pickup 4 side up so that the pickup 4 does not enter the groove of the record board R. In this case, the reflecting plate 23 also moves upward and the distance from the sensor unit 22 increases, so that the reflected light received by the sensor unit 22 becomes weak. In this case, the sensor unit 22 prevents the turntable 3 from starting to rotate. The threshold of the received light amount is set in advance.

  With the above configuration, first, when the tone arm 5 in FIG. 15 is at the solid line stop position, the light emitting / receiving sensor portion 22 of the reflective photointerrupter 21 is formed on the transparent glass base substrate 6. Since there is nothing directly above, no reflected light is received, and the turntable 3 remains stopped.

  Next, hold the finger arm 16 of the tone arm 5 with the hand, rotate the tone arm 5 together with the arm base 9, and reach the reproduction start position (5 s) of the record board R placed on the turntable 3. The reflector 23 on the lower side of the arm 5 reaches a position (23s) where it overlaps the sensor unit 22, but the pickup 4 side of the tone arm 5 is lifted by holding the finger hook 16 with the hand, so the reflector 23 and the sensor unit The distance from 22 is far away, and the turntable 3 is still stopped.

  When the tone arm 5s is dropped on the groove of the record board R at this position, the distance between the reflecting plate 23s and the light emitting / receiving sensor unit 22 approaches, and the light received by the sensor unit 22 is strengthened to start rotating the turntable 3. Then, the reproduction of the record board R is started.

  When the reproduction of the record board R is completed and the tone arm 5 reaches the reproduction end position indicated by the dotted line (5p), the reflector 23p at that time is disengaged from the position directly above the sensor unit 22, and the sensor unit 22 does not receive the reflected light. Therefore, the rotation of the turntable 3 stops.

  After the reproduction is finished, the tone arm 5 is returned to the position of the solid line which is the mounting position by holding the finger hook 16 by hand. At this time, the reflector 23 of the tone arm 5 passes immediately above the sensor unit 22. Since the pickup 4 side is tilted and moved so as not to damage the record board R, the distance between the reflecting plate 23 and the sensor unit 22 is large, and the turntable 3 maintains the stopped state.

  The embodiment of the present invention has been described above. However, the present invention is not limited to the contents of the above embodiment, and the size, shape, material, and the like of each component are appropriately determined within the scope of the present invention. It can be changed and implemented.

  For example, although the case 2 in the embodiment uses stone, concrete, or the like, the case can be integrated with the upper base substrate 6, for example, the whole can be made of glass, In addition, the dimensions can be appropriately changed in consideration of sound reproduction.

  For example, a 15 mm thick concrete bonded with silicon rubber to a 5 mm thick glass base substrate to make a product that balances the original sound reproduction capacity and weight, or an integrated product of a 10 mm thick glass base substrate and a housing. In addition, a glass-made turntable having a thickness of 10 mm can be used to make a product having a characteristic of being entirely made of glass.

DESCRIPTION OF SYMBOLS 1 Record player 2 Case 3 Turntable 4 Pickup 5 Tone arm 6 Base substrate 7 Air tube 8 Silicon rubber 9 Arm base 10 Through hole 11 Bearing 12 Center spindle 13 Shaft body 14 Body 14a Hole 15 Adhesive 16 Finger hook 17 Bow taper 18 Round Bow 19 Nipple 20 Air 21 Reflective Photointerrupter 22 Sensor Unit 23 Reflector R Record Record

Claims (5)

In an acoustic device that has a rotating body that can rotate with respect to the base substrate about a vertical axis on the upper surface of the base substrate, and that external vibrations affect the reproduction of the original sound,
The rotating body has a disk shape, the upper surface of the base substrate and the lower surface of the rotating body facing each other are smooth surfaces, the base substrate has a through hole from the upper surface to the lower surface, and one end of the air tube is formed at the lower end of the through hole. And connecting the upper end portion of the through hole and the outer diameter portion of the bearing, and a cylindrical body provided with a plurality of holes for internal and external conduction in the vicinity of the upper end portion is formed in a cylindrical shape at the center of the lower surface of the rotating body. The upper end opening of the body is fixed so as to be sealed at the lower surface of the rotating body, the cylindrical body is rotatably held at the bearing inner diameter portion, and an air pump that sends compressed air to the other end of the air tube is connected, An apparatus for preventing vibration of an acoustic device, wherein compressed air is sent from an air pump through an air tube into a through hole of a base substrate.   2. The vibration preventing device for an acoustic device according to claim 1, wherein the acoustic device is a record player that reproduces music of an analog record board, and the rotating body is a turntable that holds the analog record board on an upper surface.   2. The vibration preventing device for an acoustic device according to claim 1, wherein the acoustic device is a record player that reproduces music of an analog record board, and the rotating body is an arm base of a tone arm.   2. The sound according to claim 1, wherein the acoustic device is a record player that reproduces music of an analog record board, and the rotating body is a turntable that holds the analog record board on an upper surface and an arm base of a tone arm. Device vibration prevention device.   A reflective photo-interrupter is placed upwards below a transparent glass base substrate, a reflective plate is provided below the tone arm, and the reflective photo-interrupter captures the reflected light from the reflective plate, thereby Detecting the position of the tone arm in the rotation direction of the tone base and the tilting position in the vertical direction when playing the board, and controlling the rotation and stop of the turntable based on the position information The vibration preventing device for an acoustic device according to claim 3 or 4, wherein:

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