JP2019126002A - Sound wave transmitter and shield machine including the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sound wave transmitter having high pressure resistance with high reliability under a large depth and suitable for miniaturization. SOLUTION: This sound wave transmitter 10 is watertightness in which a vibrating plate 2 and a void portion E inside itself defined by a peripheral wall including the vibrating plate 2 are filled with a liquid while supporting the vibrating plate 2 so as to vibrate. The housing 1 is provided in the housing 2, the oscillator 3 is provided in the housing 2 to vibrate the vibrating plate 2, and the housing is attached to the housing 1 to prevent liquid from entering the housing from outside the housing. A pressure balancing plug 20 for balancing the external hydraulic pressure and the internal hydraulic pressure is provided. [Selection diagram] Fig. 1

Description

  The present invention relates to a technology for transmitting sound waves in water or soil, and more particularly to a sound wave transmitter suitable for use under high water pressure and a shield machine provided with the same.

  Generally, the external pressure increases with depth in water or soil. Therefore, if the inside of the casing of the sound wave transmitter of this type has a sealed structure, an external pressure corresponding to the depth acts on the outside of the diaphragm of the sound wave transmitter. Therefore, in order to generate a sound wave, it is necessary to push the diaphragm from the inside to the outside with a force exceeding the external pressure, and there is a problem that a large output corresponding to the depth is required.

  Here, as a sound wave transmitter having a large generation stress corresponding to a large depth, Patent Document 1 uses a giant magnetostrictive element that vibrates due to magnetostriction (distortion) to obtain a large output corresponding to the depth. Techniques corresponding to depth are disclosed. Further, Patent Document 2 discloses a technique for canceling the pressure difference acting on both sides of the diaphragm by providing an opening in the case of the sound wave transmitter and enabling external water to freely enter and exit from the case. . According to the technology described in Patent Document 2, sound waves can be transmitted even under a large depth of external pressure.

JP, 2010-141540, A JP, 2010-182804, A

However, as in the technology described in Patent Document 1, with the structure in which the casing is simply sealed in consideration of the entry of impurities into the interior of the casing, the vibration of the diaphragm is caused by the pressure difference between the inside and the outside of the casing. There is a problem that it is obstructed or the element inside the sound wave transmitter is damaged.
On the other hand, as in the technology described in Patent Document 2, the structure in which the opening is provided in the case to allow external water to enter and exit from the case is a case where there are many impurities such as sand and stone in the ground. Immersion of impurities into the interior may cause damage to elements inside the sound wave transmitter.
Therefore, the present invention has been made focusing on such a problem, and it has high operability and pressure resistance with high reliability even when it is used under a large depth, and it is possible to miniaturize it. An object of the present invention is to provide a suitable sound wave transmitter and a shield machine including the same.

In order to solve the above problems, in the sound wave transmitter according to one aspect of the present invention, there is provided a diaphragm, and an internal void portion defined by a peripheral wall that vibratably supports the diaphragm and includes the diaphragm. A liquid-tight case filled with liquid, an oscillator provided in the case to vibrate the diaphragm, and a state attached to the case to prevent the liquid outside the case from entering the case And pressure equalizing means for equalizing the fluid pressure inside the case with the fluid pressure outside the case.
Moreover, in order to solve the said subject, the shield machine which concerns on 1 aspect of this invention is characterized by providing the sound wave transmitter which concerns on 1 aspect of this invention.

  According to the sound wave transmitter according to one aspect of the present invention, the internal space portion is provided with a watertight case filled with liquid, and the pressure balance means attached to the case is used to control the pressure inside and outside the case. By balancing, it is possible to cancel the pressure difference between the inside and outside of the case acting on the diaphragm and to reduce the action of the external pressure on the elements inside the oscillator. Therefore, it is not necessary to set the element to withstand voltage specifications. As a result, even when the apparatus is used at a large depth, the increase in size and cost of the apparatus can be suppressed, and the sound wave can be generated under high water pressure by the compact sound wave transmitter.

And since this pressure balance means balances the fluid pressure inside the case with the fluid pressure outside the case while preventing the liquid outside the case from invading inside the case, the case for the fluid outside the case is Invasion inside the body is prevented. Therefore, even under the situation where there are many impurities such as sand and stones in the soil, the entry of the impurities into the inside of the housing is prevented. Therefore, even when used at great depths, it has reliable operability and pressure resistance.
Further, according to the shield machine according to one aspect of the present invention, since the sound wave transmitter according to one aspect of the present invention is provided, the equipped sound wave transmitter is small even when used under a large depth. It has high reliability and high pressure resistance at deep depth.

Here, in the sound wave transmitter according to one aspect of the present invention, the pressure balance means is a cylinder attached to the housing, and a fluid pressure outside the housing and a liquid inside the housing which is fitted to the cylinder. It is preferable to have a piston that slides according to the pressure difference between the inside and the outside so as to balance the pressure.
Preferably, the pressure balancing means further comprises an elastic member for preventing vibration of the piston accompanying vibration of the diaphragm. Preferably, the pressure balancing means further comprises damper means for preventing the vibration of the pressure balancing means itself when the diaphragm is vibrating. Such a configuration is suitable for preventing the vibration of the pressure balancing means itself caused by the vibration of the diaphragm.

  As described above, according to the present invention, the pressure inside the case and the pressure inside the case of the sound wave transmitter can be prevented while preventing the entry of impurities into the case even when used at a large depth. Can be balanced to prevent the buckling of elements inside the oscillator such as a giant magnetostrictive element, and can emit a sound wave with a relatively small generated stress. Accordingly, it is possible to provide a sound wave transmitter having a reliable operation and pressure resistance at a large depth and suitable for miniaturization, and a shield machine including the same.

BRIEF DESCRIPTION OF THE DRAWINGS It is explanatory drawing of one Embodiment of the sound wave transmitter which concerns on 1 aspect of this invention, The same figure (a) shows the cross section containing an axis line, (b) has shown the right side of (a). It is a principal part enlarged view of the part of the pressure balance plug with which the sound wave transmitter of FIG. 1 is mounted | worn. It is typical explanatory drawing of the tunnel excavation method by a shield machine provided with the sound wave transmitter of FIG. It is a schematic diagram ((a)-(c)) explaining operation | movement of the pressure balance plug with which the sound wave transmitter of FIG. 1 is mounted | worn.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings as appropriate. The sound wave transmitter of this embodiment has water pressure resistance performance at a large depth and is suitable for miniaturization.
The drawings are schematic. Therefore, it should be noted that the relationship between the thickness and the plane dimension, the ratio, etc. is different from the actual one, and some parts have different dimensional relationships and ratios among the drawings. In addition, the embodiments and modifications described below illustrate apparatuses and methods for embodying the technical idea of the present invention, and the technical idea of the present invention includes materials, shapes, and the like of components. The structure, arrangement, etc. are not specified in the following embodiments.

As shown in FIG. 1, the sound wave transmitter 10 includes a watertight case 1 having a sealing structure, and an oscillator 3 provided in the case 1 to vibrate the diaphragm 2. The housing 1 has a disk-shaped bottom portion 1a and a cylindrical portion 1b constituting a cylindrical side surface. In this example, a disk-shaped diaphragm 2 is coaxially mounted on the opening side facing the bottom surface portion 1 a of the housing 1.
The bottom surface portion 1a and the cylindrical portion 1b are inlay-fitted with each other, and the space between the outer peripheral surface of the bottom surface portion 1a and the inner peripheral surface of the cylindrical portion 1b is stopped by a sealing member using an O ring 34, Infiltration of liquid and impurities from the outside into the interior is prevented. The diaphragm 2 is flexibly supported so as to be able to vibrate on the front side (right side in FIG. 6A) of the cylindrical portion 1b, and a space E is formed inside itself defined by a peripheral wall including the diaphragm 2. There is.

  A support pipe 4 is coaxially mounted on an outer side surface of the bottom portion 1 a via an annular support flange 5. The support flange 5 is fixed to the outer surface of the bottom portion 1 a by a plurality of fixing bolts 32. A sealing member using an O-ring 35 is used to stop water between the mounting surface of the support flange 5 and the outer surface of the bottom portion 1a to prevent the liquid and impurities from entering the inside from the outside. In this example, the connecting portion between the support pipe 4 and the support flange 5 is covered with a MC nylon cover 36 so as to cover the periphery.

  The oscillator 3 is a super magnetostrictive actuator that vibrates by magnetostriction (distortion) in order to oscillate a sound wave by the diaphragm 2, and is disposed outside the giant magnetostrictive element and a columnar giant magnetostrictive element (not shown). And a disc spring and the like. Since the coil is formed of an enameled wire or the like, if the connection portion between the coil and the cable 8 is waterproofed, the oscillator 3 operates normally without shorting even if it is placed in water.

The oscillator 3 of this embodiment has the housing 1 such that the displacement direction of the giant magnetostrictive element coincides with the facing direction of the opening of the housing 1 (that is, the portion on which the diaphragm 2 is mounted) and the bottom portion 1a. Coaxially with the inner center of the The base surface of the oscillator 3 is fixed to the bottom portion 1 a by a plurality of fixing bolts 31, and the oscillator 3 is disposed coaxially with the center of the disk-shaped diaphragm 2.
The bottom portion 1a of the housing 1 is formed with a drawing hole for drawing out the two cables 8 drawn from the oscillator 3 from the inside of the housing 1 to the outside, and the housing 1 is underwater etc. for the other parts. The liquid such as water outside the housing 1 is prevented from infiltrating the inside of the housing 1 when placed in the liquid.

  The two cables 8 are connected to both ends of the coil constituting the oscillator 3 and are drawn out of the housing 1 through the bottom surface portion 1 a. When a power supply is connected to the cable 8 and power is supplied from the power supply to the cable 8, the super magnetostrictive actuator of the oscillator 3 vibrates, and the vibration vibrates the diaphragm 2 to emit a low frequency sound wave. It has become.

In the present embodiment, a female screw is formed at the center of the back surface of the diaphragm 2, and a male screw is formed at the end of the output end of the oscillator 3. The output end of the oscillator 3 is screwed into the female screw on the back surface of the diaphragm 2. It is fixed by the fixing nut 33.
The number of super magnetostrictive actuators constituting the oscillator 3 is not limited to one. For example, a plurality of giant magnetostrictive actuators are housed in the housing 1 such that the displacement direction of the giant magnetostrictive element coincides with the facing direction of the opening of the housing 1 and the bottom portion 1a, and the output end of each giant magnetostrictive actuator is It may be connected to the diaphragm 2, and the base end may be supported by the bottom surface portion 1a.

The diaphragm 2 is a plate that vibrates with the vibration of the oscillator 3 and transmits a low frequency sound wave, and in the present embodiment, an annular ring in which the two packings 6 are formed on the peripheral portion of the diaphragm 2. The support portion is disposed at the opening of the housing 1 in a state in which the support portion is sandwiched from both sides in the axial direction. The shape of the diaphragm 2 is a disk shape smaller than the opening of the housing 1.
The packing 6 of the present embodiment is a cushion rubber coaxially formed in an annular shape, and the axially inner first packing 6 a has a diameter equal to the inner and outer diameters of the side end 1 d of the housing 1. The axially outer second packing 6 b has a diameter equal to the outer diameter of the side end 1 d of the housing 1.

The two packings 6 are sandwiched between the side end 2 b of the housing 1 and the cap-like diaphragm holding nut 7 so as to overlap with the annular support provided on the diaphragm 2. It is done. The packing 6 fills the space between the diaphragm 2 and the side surface portion 1 b, and the space E inside the housing 1 is sealed. The space E is filled with a liquid such as water between the inside of the case and the oscillator 3.
The packing 6 may be replaced by packing other than rubber as long as it has flexibility. If the clearance between the diaphragm 2 and the side end 2b of the housing 1 is properly provided, the deformation of the packing 6 due to the liquid pressure outside the sound wave transmitter 10 when the sound wave transmitter 10 is disposed in the liquid It can prevent damage. The clearance is appropriately changed depending on the material and thickness of the packing 6 and the conditions such as the fluid pressure outside the sound wave transmitter 10 and the like.

  The housing 1 of the present embodiment has the O-ring interposed at a position at which two water supply and drainage bolts 26 are separated by 180 degrees in the circumferential direction at a position in contact with the inner surface of the bottom surface 1a with respect to the cylindrical portion 1b. It is attached in a removable manner. Thus, when filling the space E with liquid, first, the upper and lower water supply and drainage bolts 26 are removed, and the diaphragm 2 is directed downward and the bottom surface portion 1a is directed upward. Then, the water is supplied from the mounting hole of one of the water supply and discharge bolts 26 and the air is exhausted from the mounting hole of the other water supply and discharge bolt 26.

Next, when the injection is drained from the mounting hole of the other pouring / draining bolt 26, the other pouring / draining bolt 26 is attached to the mounting hole, and in that state, until the overflowing from the mounting hole of one feeding / draining bolt 26 continues Continue water injection. Thereafter, when the injection overflows from the mounting hole of one of the water supply and discharge bolts 26, it is determined that the space between the inside of the housing and the oscillator 3 is filled with the liquid, and the one water supply and discharge bolt 26 is attached. E can be filled with liquid.
Thus, in the sound wave transmitter 10, the oscillator 3 supports the diaphragm 2 from the inner surface side, and the flexible packing 6 is connected in a state of being interposed between the diaphragm 2 and the side end 2b. Therefore, the diaphragm 2 and the housing 1 are displaced relative to each other without being restrained by the housing 1, and the diaphragm 2 can be vibrated even with a large water pressure.

Here, the sound wave transmitter 10 is attached to the housing 1 to prevent the liquid outside the housing from invading the inside of the housing, and the liquid pressure outside the housing 1 and the liquid inside the housing 1 A pressure balancing plug 20 is provided which is a pressure balancing means for balancing pressure.
The mounting portion 2 c of the pressure balancing plug 20 is formed to penetrate along the radial direction on the side surface of the cylindrical portion 1 b of the housing 1. An internal thread is formed on the inner peripheral surface of the mounting portion 2c. The pressure balancing plug 20 has a hollow cylindrical cylinder 21, and a male screw formed on the outer peripheral surface of the cylinder 21 is screwed into a female screw of the mounting portion 2 c. The space between the pressure balancing plug 20 and the mounting portion 1c of the housing 1 is stopped by a sealing member (not shown) using, for example, a liquid packing material or the like to prevent the liquid and impurities from entering the inside from the outside. ing.

Specifically, the pressure balancing plug 20 has a hollow cylindrical cylinder 21 attached to the housing 1 and a solid cylindrical piston 22 fitted in the cylinder 21. An annular engaging portion 21t is formed at the lower portion (side of the void portion E) of the cylinder 21 so as to protrude radially inward, and the inner diameter portion of the engaging portion 21t is the pressure on the inner side of the void portion E. It has become a part of
The inner diameter of the engaging portion 21 t is smaller than the outer diameter of the piston 22, and the piston 22 mounted inside is prevented from moving below the upper surface of the engaging portion 21 t. In addition, a concave annular groove is formed substantially at the center of the outer peripheral surface of the piston 22, and the O ring 25 mounted in the concave annular groove stops the water between the inner peripheral surface of the cylinder 21 and the outside Infiltration of liquid and impurities from the inside is prevented.

An internal thread is formed on the inner peripheral surface at the top of the cylinder 21, and an annular cap 23 having an external thread formed on the outer peripheral surface is attached to the internal thread from the upper side of the cylinder 21. The central through hole 23 h of the annular cap 23 is an introduction port for introducing the external liquid, and the external hydraulic pressure introduced from the through hole 23 h is axially below the upper surface 22 m of the piston 22 ( It is comprised so that it may press toward the space | gap part E side).
Thus, when the upper surface 22m of the piston 22 is pressed, the pressure balancing plug 20 balances the fluid pressure inside the case with the fluid pressure outside the case (in other words, with the fluid pressure outside the case The piston 22 is slid along the axial direction according to the pressure difference between the inside and the outside so as to equalize the fluid pressure inside the housing.

Furthermore, the pressure balancing plug 20 of the present embodiment has vibration preventing means for preventing the vibration of the pressure balancing means itself accompanying the vibration of the diaphragm. The vibration preventing means of the present embodiment is a porous rubber elastic member 24 formed in a solid cylindrical shape. The elastic member 24 has an outer diameter equal to the diameter of the piston 22 and is internally mounted so as to fill the space E side in the cylinder 21 so as to face the sliding movement direction of the piston 22.
That is, the pressure balancing plug 20 has a double structure in which the piston 22 that slides and the elastic member 24 that prevents the vibration of the piston 22 are coaxially arranged. In the lower part of the cylinder 21, the lower surface of the elastic member 24 abuts on the upper surface of the engaging portion 21t, thereby restraining movement of the elastic member 24 below the upper surface of the engaging portion 21t.

Next, an example of tunnel excavation by a shield machine equipped with the sound wave transmitter 10 will be described. As shown in FIG. 3, the sound wave transmitter 10 is an example used for position detection at the time of underground installation, and in the same figure, in the urban area C, underground installation is performed by the shield machine 40 in deep underground UG. Shows an image.
Here, in the construction of an underground structure such as a tunnel construction or a boring construction, the construction will be progressed along the line of the plan after accurately grasping the current position in the ground. As a method of accurately detecting the current position (measurement point) in the ground, a sound wave is transmitted from a sound wave transmitter 10 provided in a digging machine such as a shield machine at three or more reception points whose coordinates are known. The position of the excavator is calculated by measuring the propagation time to each receiving point.

  That is, as shown in the figure, in the shield machine (boring machine) 40, the insertion device 50 equipped with the sound wave transmitter 10 is disposed at an appropriate position of the bulkhead 41, and the push-pull provided in the insertion device 50 is provided. By the back and forth operation in the axial direction by the means, the sound wave transmitter 10 can be moved between the transmitting position and the retracted position. In addition, about the insertion apparatus 50, since a well-known technique (for example, refer Unexamined-Japanese-Patent No. 2010-59676) can be employ | adopted, detailed description is abbreviate | omitted.

In this embodiment, as shown to the same figure, the oscillator 10 is arrange | positioned at the face side from the inner side of the shield machine 40, and the underground position detection of the shield machine 40 is performed. In this embodiment, an example used for the shield machine 40 is shown, but it may be used, for example, for a TBM (tunnel boring machine) or a propulsion unit, and the excavator used for the sound wave transmitter of the present invention is a shield machine It is not limited to.
The shield machine 40 has a cutter head 41 for excavating, and a shield portion 42 located behind the cutter head 41 to protect various facilities inside the shield machine 40. A front portion of the shield portion 42 is partitioned by a bulkhead 43, and a chamber 45 in which the soil excavated by the cutterhead 41 is temporarily deposited is formed between the cutterhead 41 and the bulkhead 43.

  An opening 44 is formed in the bulkhead 43, and the insertion device 50 is configured to be able to insert the sound wave transmitter 10 from the inside of the shield portion 42 to the face side. Here, the sound wave transmitter 10 installed on the outside of the shield machine 40 is weak to vibration and impact, and there is a possibility of failure or breakage. In the present embodiment, the insertion device 50 is fixed to the bulkhead 43. At the time of ground position detection, since the sound wave transmitter 10 is inserted from the opening 44 to the face side and collected after measurement, failure or damage of the sound wave transmitter 10 is prevented.

  In the urban area C, a receiving unit is installed at a predetermined position. In the example of the same figure, the weir holes 65 and 75 are drilled from the ground at a position separated by, for example, about 25 to 100 m in front of the underground installation position by the shield machine 40. The first receiving unit 60 then hangs down the cable 64 on which the three receivers 61, 62, 63 are mounted, and the second receiving unit 70 receives the three receivers 71, 72. , 73 are suspended in a suspended state.

  When detecting the underground position of the shield machine 40, first, the excavation by the shield machine 40 is stopped, and a slit or opening (not shown) formed in the cutter head 41 corresponds to the position of the opening 44 of the bulkhead 43. The position of the cutter head 41 is adjusted. Next, by operating the pressure control valve provided in the insertion device 50, the pressure in the conduit and the pressure difference on the face side are equalized. Then, the sound wave transmitter 10 is disposed on the face side by pushing the insertion tube to the face side by the pushing and pulling means.

When the sound wave transmitter 10 is placed at a predetermined position, the sound wave transmitter 10 is operated to carry out measurement work by the sound wave transmitter 10. Since the coordinates of the first receiver unit 60 and the second receiver unit 70 are known for the three receivers 61, 62, 63 and the three receivers 71, 72, 73, the reception points for these three reception points are used. The position of the shield machine 40 can be calculated by transmitting the sound wave S from the sound wave transmitter 10 provided in the shield machine 40 and measuring the propagation time to each receiving point.
After measurement, the sound wave transmitter 10 is drawn into the bulkhead 43 by operating the pushing and pulling means, and then the gate is closed, and the drain valve provided in the insertion device 50 is opened to drain water and earth in the pipeline. The sound wave transmitter 10 is protected by a protective case provided in the insertion device 50, so that the sound wave transmitter 10 is prevented from being damaged when inserted into excavated soil.

Next, the operation and effect of the above-described sound wave transmitter 10 will be described.
As described above, the sound wave transmitter 10 according to this embodiment includes the watertight housing 1, the oscillator 3 supported by the bottom portion 1 a of the housing 1, and the diaphragm 2 supported by the tip of the oscillator 3. Since the packing 6 which is a flexible connection portion for flexible connection between the housing 1 and the diaphragm 2 is provided, sound waves can be efficiently transmitted in water and soil.

In particular, in the sound wave transmitter 10 of the present embodiment, the space E in the watertightly defined housing 1 is filled with the liquid, and the oscillator 3 has a giant magnetostrictive element whose giant magnetostrictive actuator has a large driving force. Thus, the diaphragm 2 of the sound wave transmitter 10 can transmit sound waves even at a large water pressure.
That is, since the super magnetostrictive element constituting the oscillator 3 is driven by the electromagnetic coil, it can transmit a low frequency sound wave. The super magnetostrictive actuator of the oscillator 3 can be operated by a normal amplifier, and a special high voltage output device such as a ceramic type is not necessary. The super magnetostrictive element constituting the oscillator 3 has a large driving force, and the size of the actuator accommodated in the inside of the housing 1 can be selected according to the size of the housing 1 such as the diameter of the cylindrical portion 1b. In addition, since the structure is simple, the device can be miniaturized.

  Therefore, the sound wave transmitter 10 according to the present embodiment has high pressure resistance with high reliability at a large depth, and can withstand a large water pressure to transmit a desired sound wave. Further, since the driving force of the giant magnetostrictive element is large, the acoustic wave transmitter 10 can be miniaturized. And since this underwater sound wave transmitter 10 is filled with the internal space E formed by the peripheral wall including the diaphragm 2 with the liquid, there is no air chamber portion, so theoretically 1 It can operate normally even at water depths of 10,000 m or more.

Furthermore, as shown in FIG. 4, the underwater acoustic wave transmitter 10 according to the present embodiment is attached to the housing 1 to prevent the liquid such as water from entering the housing 1 from entering the housing 1. Since the pressure balancing plug 20 for balancing the fluid pressure inside the housing 1 with the fluid pressure outside the body 1 is provided, as shown in FIGS. (A) and (b), the diaphragm 2 is under deep water pressure. Even if it can, sound waves can be transmitted in a stable state.
That is, as shown in FIG. 6A, when the fluid pressure outside the housing 1 is low, the pressure balancing plug 20 is also weak in the force with which the upper surface 22m of the piston 22 is pressed. The elastic member 24 is in the extended state, and the sliding position of the piston 22 in the cylinder 21 is also held at the low pressure equilibrium position near the outside of the housing 1 according to the low pressure in the inner and outer pressure.

  On the other hand, as shown in FIG. 6B, when the fluid pressure outside the case 1 is high under a large water pressure, the fluid pressure outside the case 1 causes the upper surface 22m of the piston 22 to be When pressed, the fluid pressure inside the casing is made equal to the fluid pressure outside the casing (in other words, the fluid pressure outside the casing and the fluid pressure inside the casing are equalized), In response to the pressure difference between the inside and the outside, the piston 22 slides in the axial direction in the space E side, and is held at the high pressure equilibrium position near the inside of the housing 1 according to the high pressure.

  Thus, by equalizing the pressure inside and outside the housing 1, the pressure difference between the inside and outside of the housing 1 acting on the diaphragm 2 can be cancelled, and the action of the external pressure on the elements inside the oscillator 3 can be reduced. Therefore, it is not necessary to set the element to withstand voltage specifications. Therefore, even when the sound wave transmitter 10 is used at a large depth, it is possible to generate a sound wave under high water pressure by suppressing the size increase and cost increase of the device and by the compact configuration. In particular, the sliding movement of the piston 22 in the space E along the axial direction is performed in a state in which the liquid outside the housing is prevented from entering the inside of the housing, and thus sand, stone, etc. in the soil Even in a situation where there are many impurities, it is possible to reliably prevent the liquid and impurities from entering the inside from the outside.

Here, in the case where the sound wave transmitter 10 of the present embodiment transmits a sound wave in a state where the pressure inside and outside the sound wave transmitter 10 is balanced by the pressure balance plug 20, as shown in FIG. The super-magnetostrictive actuator is energized, the super-magnetostrictive element expands, and the extra-magnetostrictive element pushes the diaphragm 2 outward to generate a pressure wave.
At this time, as shown in the figure, the volume of the air gap E inside the housing 1 is increased by the amount of extension of the giant magnetostrictive element. Although the pressure inside the housing 1 is equal to the external pressure by the pressure regulation action of the pressure balancing plug 20 described above, negative pressure is applied to the inside of the housing 1 as the volume of the space E increases. Therefore, as shown in the drawing, the pressure balancing plug 20 further slides so that the piston 22 inside the cylinder 21 is drawn toward the gap E side of the housing 1 so as to balance the pressure inside and outside the housing. Do.

Due to this slide movement, in addition to the sound waves emitted from the vibration plate 2, the sound wave transmitter 10 generates sound waves in reverse phase to the sound waves emitted from the vibration plate 2 from the pressure balancing plug 20. Therefore, there is a concern that the sound wave of this antiphase will attenuate the sound wave emitted from the diaphragm 2.
Therefore, in the present embodiment, a double structure in which an elastic member 24 made of porous rubber is installed inside the cylinder 21 as a vibration preventing means for preventing the vibration of the piston 22 inside the pressure balancing plug 20 when the diaphragm 2 vibrates. Therefore, the pressure balance means itself is prevented from vibrating when the diaphragm 2 vibrates, and generation of sound waves of opposite phase from the pressure balance plug 20 is prevented. In addition, it is preferable that the natural frequency of the pressure balancing means is provided so as to deviate from the frequency of the vibration plate 2 to transmit, and also in the present embodiment, the natural frequency of the piston 22 of the pressure balancing plug 20 is It is provided so as to deviate from the oscillation frequency of the diaphragm 2.

As described above, this sound wave transmitter 10 is suitable for downsizing while having highly reliable operation and pressure resistance at large depths. In addition, the sound wave transmitter which concerns on this invention is not limited to the said embodiment, A various deformation | transformation is possible if it does not deviate from the meaning of this invention.
For example, in the above embodiment, the packing 6 is an example of the connection portion of the sound wave transmitter according to the present invention, and two pieces of the packing 6 may not be prepared. For example, one packing 6 and two diaphragms 2 may be superimposed, and the outer periphery of the packing 6 may be flexibly connected to the cylindrical portion 1 b of the housing 1.

  In short, the flexible packing 6 only needs to flexibly connect the diaphragm 2 and the cylindrical portion 1b. The connection part by the packing 6 or the like has flexibility such as rubber which fills the space between the diaphragm 2 and the cylindrical part 1b, provided that the diaphragm 2 and the cylindrical part 1 are connected flexibly. The inside and the outside at the top of the housing 1 are shut off, and the diaphragm 2 can vibrate without being restrained by the housing 1.

Reference Signs List 1 housing 1a bottom portion 1b cylindrical portion 1c mounting portion 1d (on the opening side) side end portion 2 diaphragm 3 oscillator (super magnetostrictive actuator)
4 support pipe 5 support flange 6 packing 6a first packing 6b second packing 7 diaphragm holding nut 8 cable 9 O ring 10 sound wave transmitter 20 pressure balancing plug (pressure balancing means)
21 cylinder 22 piston 23 cap 24 elastic member (porous rubber)
25 O-ring 26 Note Drain bolt 31 Fixing bolt 32 Fixing bolt 33 Fixing nut 34 O-ring 35 O-ring 36 Cover 40 Shield machine 41 Bulkhead 50 Insertion device 60 First receiving unit 70 Second receiving unit E Air gap

Claims (8)

A diaphragm,
A watertight housing in which the diaphragm is vibratably supported and the internal space defined by the peripheral wall including the diaphragm is filled with liquid;
An oscillator provided in the housing to vibrate the diaphragm;
Pressure balancing means for equalizing the fluid pressure inside the casing with the fluid pressure outside the casing while being attached to the casing to prevent the liquid outside the casing from invading the inside of the casing;
Sound wave transmitter characterized by having.   The pressure balance means is a cylinder attached to the housing, and slides according to a pressure difference between the inside and the outside so as to balance the liquid pressure outside the housing and the liquid pressure inside the housing by being fitted into the cylinder. The sound wave transmitter according to claim 1, further comprising: a moving piston.   The sound wave transmitter according to claim 2, wherein the pressure balancing means further comprises an elastic member that prevents the vibration of the piston accompanying the vibration of the diaphragm.   The sound wave transmitter according to claim 3, wherein the elastic member is installed on the side of the space in the cylinder so as to face the sliding movement direction of the piston.   The sound wave transmitter according to claim 4, wherein the elastic member is a porous rubber filled on the side of the space in the cylinder so as to face the sliding movement direction of the piston.   The sound wave transmitter according to any one of claims 1 to 5, wherein the natural frequency of the pressure balancing means is provided so as to deviate from the frequency of transmission of the diaphragm.   The sound wave transmitter as described in any one of Claims 1-6 used for the position detection at the time of underground construction. A shield machine comprising the sound wave transmitter according to any one of claims 1 to 7.

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