JP2005119839A - Object floating device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To efficiently, stably and approximately uniformly vibrate the whole of a vibration plate when the vibration plate having a plurality of resonance frequencies is excited by a vibrator at the excitation side. <P>SOLUTION: The object floating conveying device 11 floats the object 13 by radiation pressure of a sound wave from the vibration plate 12 by exciting the vibration plate 12 having the plurality of resonance frequencies by an excitation means. One end of the vibration plate 12 is tightened to a hone 15 fixed to the vibrator 14 and the other end is tightened to a hone 16. An excitation side vibration sensor 25 for detecting vibration at the excitation side of the vibration plate 12 is provided on the vibrator 14. A wave receiving side vibration sensor 26 for detecting the vibration at the wave receiving side of the vibration plate 12 is provided on a metal block fixed with the hone 16. An oscillator 22 is driven by a control signal from a control device 27. The control device 27 controls the oscillator 22 such that the vibration plate 12 generates a standing wave and is approximately uniformly vibrated at a stripe mode as the whole of the vibration plate 12 using a detection signal of the excitation side vibration sensor 25 and a detection signal of the wave receiving side vibration sensor 26. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an object levitation device, and more particularly to an object levitation device that excites a diaphragm having a plurality of resonance frequencies by an excitation means and levitates an object by radiation pressure of sound waves from the diaphragm.

  As an object levitating apparatus for levitating an object in the air, an apparatus using a sound wave radiation pressure has been proposed. An object levitating and conveying apparatus that uses a long flat plate-like vibrating body, levitates an object by the radiation pressure of sound waves generated by vibration of the vibrating body, and generates a traveling wave by the vibrating body to move the levitated object. It has been proposed (see, for example, Patent Document 1). In the object levitating and conveying apparatus, an excitation-side (excitation side) vibrator is provided at one end of a vibrating body, and a receiving-side vibrator is provided at the other end. In addition, a Langevin type vibrator using a piezoelectric element (piezo element) is used as the vibrator on the excitation side. In a vibrator using a piezoelectric element, the vibrator is vibrated with a required strength (amplitude) by exciting the vibrator at a resonance frequency. In order to generate a traveling wave in the vibrating body, the receiving-side vibrator is provided with a load circuit that converts the vibration energy of the vibrator into electric energy and consumes it as heat by a resistor.

  When the excitation side and the receiving side of the diaphragm are separated like a long plate, even if the diaphragm is vibrated well on the excitation side, the vibration may not be satisfactorily performed on the receiving side. Therefore, when a long diaphragm is excited by a vibrator on the excitation side, a vibrator driving power supply device has been proposed that can vibrate the entire diaphragm efficiently and stably with a simple configuration. (See Patent Document 2). The power supply apparatus for driving a vibrator described in Patent Document 2 drives a diaphragm by exciting a vibrator on an excitation side connected to one end of a long diaphragm by an oscillator, and receives the wave from the long diaphragm. Control means for controlling the oscillator by feeding back a signal from a vibration state detection means for detecting a vibration state on the side.

Specifically, as shown in FIG. 6, the vibrator driving power supply device 41 includes a main circuit 42 that constitutes an oscillator, and a control device 43. The main circuit 42 includes a phase shift control circuit (not shown) and is driven by a control signal from the control device 43. The control device 43 includes an output of a voltage sensor 45 that detects a voltage V1 supplied to the vibrator 44 on the excitation side and an output of a voltage sensor 47 that detects a voltage V2 output from the vibrator 46 on the receiving side. It is designed to be entered. The control device 43 includes a CPU (not shown), and the difference (phase difference) between the phase of the voltage V1 supplied to the vibrator 44 on the excitation side and the phase of the voltage V2 output from the vibrator 46 on the receiving side. ) Controls the output frequency of the oscillator so that the output voltage V2 becomes a maximum value or a predetermined value or more in a predetermined value or range.
Japanese Patent Laid-Open No. 2002-137817 (paragraphs [0015], [0018], [0021], FIG. 1) JP 2003-126778 A (paragraphs [0020] to [0025] of the specification, FIGS. 1 and 2)

  When the diaphragm is excited, normally, the vibration component on the receiving side can be fed back, and the voltage (current) on the excitation side can be controlled as the vibration component on the excitation side. However, in the case of a long diaphragm, since there are a plurality of resonance frequencies, there may be a vibration mode that does not satisfy “excitation-side voltage (current) = excitation-side vibration”. Further, there is a possibility of vibration at a frequency other than the desired frequency due to variations due to manufacturing tolerances. Therefore, if only the vibration on the receiving side is fed back to the control of the long diaphragm, only the receiving side vibrates well, and the entire diaphragm does not vibrate uniformly. In the apparatus described in Patent Document 2, it is possible to uniformly vibrate the diaphragm by adjusting the main circuit 42 while confirming the vibration state. However, there is a problem in that adjustment takes time. In addition, when the impedance characteristic changes due to temperature change, change with time, etc., there is a possibility of vibration in another mode.

  The present invention has been made in view of the above-described conventional problems, and its purpose is to efficiently and stably stabilize the entire diaphragm when the diaphragm having a plurality of resonance frequencies is excited by the vibrator on the excitation side. An object of the present invention is to provide an object levitation device that can be vibrated substantially uniformly.

  In order to achieve the above object, an invention according to claim 1 is an object levitation apparatus in which a diaphragm having a plurality of resonance frequencies is excited by excitation means, and the object is levitated by the radiation pressure of sound waves from the diaphragm. is there. And using the detection signal of the excitation side vibration sensor for detecting the vibration on the excitation side of the diaphragm and the detection signal of the reception side vibration sensor for detecting the vibration on the reception side of the diaphragm, A control device for controlling the excitation means is provided. Here, the “excitation side of the diaphragm” means a portion that excites the diaphragm by applying a voltage (current) to the vibrator, and the “receiving side of the diaphragm” means from the vibrator on the excitation side. The position of the diaphragm corresponding to the fixed part to which the diaphragm is connected at a distant position and the distance to the fixed part mean a part shorter than the distance to the vibrator on the excitation side. For example, even if the vibrator is directly or indirectly connected to the diaphragm, if the diaphragm is not excited by applying a voltage (current) to the vibrator, it is on the receiving side of the diaphragm.

  In the present invention, the object is levitated by the radiation pressure of the sound wave from the diaphragm excited by the excitation means. Vibration on the excitation side of the diaphragm is detected by an excitation side vibration sensor, and vibration on the receiving side of the diaphragm is detected by a receiving side vibration sensor. The control device controls the excitation means using the detection signals of both sensors. Therefore, even if the diaphragm has a plurality of resonance frequencies, the excitation side and the reception side are prevented from being vibrated at different resonance frequencies, and the entire diaphragm is efficiently and stably vibrated substantially uniformly. be able to.

  According to a second aspect of the present invention, in the first aspect of the present invention, the diaphragm is excited by a vibrator so as to generate a traveling wave. In this invention, since a traveling wave is generated from the diaphragm, the object can be conveyed in a levitated state. When a traveling wave is generated from a diaphragm, it is preferable to excite the diaphragm at a frequency slightly deviated from the resonance frequency. Therefore, when there are a plurality of resonance frequencies, in the control that feeds back only the vibration on the receiving side, This occurs when the receiving side is not vibrated uniformly, but this is not the case in the present invention, and the whole is vibrated substantially uniformly.

  According to a third aspect of the invention, in the first aspect of the invention, the diaphragm is excited so as to generate a standing wave, and the receiving side of the diaphragm is supported by a horn, The receiving side vibration sensor is attached. In this invention, since the receiving side is supported by the horn, the configuration is simplified compared to a configuration in which a vibrator is also provided on the receiving side.

  The invention according to claim 4 is the invention according to any one of claims 1 to 3, wherein the diaphragm is vibrated in a fringe mode. Therefore, in this invention, compared with the case where the diaphragm is vibrated in the lattice mode, the generation of noise is suppressed and the diaphragm is vibrated in a stable state, so that reliability is improved.

  According to the present invention, when the diaphragm having a plurality of resonance frequencies is excited by the vibrator on the excitation side, the entire diaphragm can be efficiently and stably vibrated substantially uniformly.

(First embodiment)
A first embodiment embodying the present invention will be described below with reference to FIGS. FIG. 1 is a schematic perspective view of an object levitation transfer device, and FIG. 2 is a schematic side view of the object levitation transfer device.

  As shown in FIG. 1, the object levitation transfer device 11 includes a long diaphragm 12. The long length means a length that is at least 10 times the wavelength when the diaphragm 12 vibrates. The diaphragm 12 is formed in a rectangular flat plate shape and is wider than the object 13 to be conveyed. The diaphragm 12 is formed to have a length having a plurality of resonance frequencies. A horn 15 is fastened at one end of the diaphragm 12 (left end in FIG. 1) with a screw (not shown). A horn 16 is fastened to the other end of the diaphragm with a screw (not shown) at its tip. Each of the horns 15 and 16 is formed in a flat and substantially rectangular parallelepiped shape, and is attached to the diaphragm 12 in a state orthogonal to the longitudinal direction at both longitudinal ends.

  The horn 15 is fixed to the vibrator 14 on the surface opposite to the surface to which the diaphragm 12 is fastened. The front end surface of the horn 15 is formed on a plane orthogonal to the axial direction of the vibrator 14, and the horn 15 and the central axis of the vibrator 14 are arranged in a state extending in the vertical direction.

  A so-called Langevin type vibrator is used as the vibrator 14 and includes a pair of ring-shaped piezoelectric elements 17a and 17b. A ring-shaped electrode plate 18 is disposed between the piezoelectric elements 17a and 17b, and metal blocks 19a and 19b that are in contact with the surface of the piezoelectric elements 17a and 17b on the side opposite to the side in contact with the electrode plate 18 are attached by bolts (not shown). The vibrator 14 is configured by tightening and fixing. The bolt is screwed into a screw hole (not shown) formed in the metal block 19a from the metal block 19b side. Both metal blocks 19a and 19b are in a state of being electrically connected to each other via bolts.

  As shown in FIG. 2, a flange 20 is formed at the upper end of the metal block 19 a, and the metal block 19 a is fitted into a hole (not shown) formed in the base plate 21 with a bolt (not shown) to the base plate 21. It is fixed. The receiving-side horn 16 is fixed to the base plate 21 via a metal block 19a.

  The vibrator 14 for exciting the horn 15 fastened to the excitation side of the diaphragm 12 is connected to an oscillator 22. The electrode plate 18 is connected to the oscillator 22 via the wiring 23a, and the ground terminal of the oscillator 22 is connected to the metal block 19b via the wiring 23b. The oscillator 22 includes a phase shift control circuit (not shown). The vibrator 14, the horn 15 and the oscillator 22 constitute excitation means for exciting the diaphragm 12.

  The object levitation transfer device 11 is configured to generate a standing wave from the diaphragm 12, and includes a propulsive force applying unit that applies a propulsive force to the object 13 in the levitation state. In this embodiment, a nozzle 24 that blows compressed air from behind on the object 13 is provided as a propelling force applying means. A plurality of nozzles 24 are provided, but only one is shown.

  The vibrator 14 is provided with an excitation-side vibration sensor 25 that detects vibration on the excitation side of the diaphragm 12. The excitation side vibration sensor 25 is configured to output a voltage V1 corresponding to the vibration of the vibrator 14. The metal block 19a to which the horn 16 is fixed is provided with a receiving-side vibration sensor 26 that detects vibration on the receiving side of the diaphragm 12. The receiving side vibration sensor 26 is configured to output a voltage V <b> 2 corresponding to the vibration of the horn 16.

  The oscillator 22 is driven by a control signal from the control device 27. The control device 27 includes a CPU (not shown), and the excitation side vibration sensor 25 and the reception side vibration sensor 26 are connected to the CPU via an A / D converter and an interface (both not shown). . The control device 27 controls the excitation means of the diaphragm 12 using the detection signal of the excitation side vibration sensor 25 and the detection signal of the reception side vibration sensor 26.

  The control device 27 calculates the magnitude and phase of the vibration components on the excitation side and the reception side based on the detection signals of the excitation side vibration sensor 25 and the reception side vibration sensor 26, and the diaphragm 12 generates a standing wave. The oscillator 22 is controlled so that it is generated and vibrates substantially uniformly as a whole in the stripe mode.

Next, the operation of the object levitation transfer device 11 configured as described above will be described.
The oscillator 22 is driven by a control signal from the control device 27, and the vibrator 14 is excited at a predetermined resonance frequency (for example, around 20 kHz). When the vibrator 14 is excited, the horn 15 is longitudinally vibrated, and the diaphragm 12 is excited via the horn 15 to perform flexural vibration. The object 13 is held in a state of being levitated from the surface of the diaphragm 12 by the radiation pressure of the sound wave radiated from the diaphragm 12. In this state, compressed air is injected from the nozzle 24 to apply a propulsive force to the object 13, and the object 13 is conveyed in a floating state from one end side to the other end side of the diaphragm 12. By stopping the jet of compressed air from the nozzle 24, the conveyance of the object 13 is stopped, and the object 13 is held in a fixed position in a floating state. When the driving of the oscillator 22 is stopped, the vibration of the diaphragm 12 is stopped, and the object 13 is stopped while being placed on the diaphragm 12.

  The vibration on the excitation side of the diaphragm 12 is detected by the excitation side vibration sensor 25, and a detection signal is output from the excitation side vibration sensor 25 as the voltage V1. The vibration on the receiving side of the diaphragm 12 is detected by the receiving side vibration sensor 26, and the detection signal is output from the receiving side vibration sensor 26 as the voltage V2. The control device 27 inputs voltages V1 and V2 which are detection signals of the excitation side vibration sensor 25 and the reception side vibration sensor 26, and calculates the magnitude (amplitude) and phase of the vibration component on the excitation side. Then, a command signal for causing the oscillator 22 to excite the vibrator 14 is output so that the diaphragm 12 vibrates substantially uniformly as a whole.

  The control device 27 changes at least one of the phase and the frequency of the oscillator 22 when the vibration state on the excitation side and the reception side of the diaphragm 12 deviates from a predetermined range set in advance. When it is confirmed from the outputs of the excitation-side vibration sensor 25 and the reception-side vibration sensor 26 that the vibration state of the diaphragm 12 has returned to a substantially uniform state as a whole, the driving of the oscillator 22 is continued under those conditions.

  That is, the control device 27 detects the detection signal (voltage V 1) of the excitation side vibration sensor 25 that detects the vibration on the excitation side of the diaphragm 12 and the reception side vibration sensor 26 that detects the vibration on the reception side of the diaphragm 12. The excitation signal of the diaphragm 12 is controlled using the detection signal (voltage V2). When the diaphragm 12 has a plurality of resonance frequencies, when a voltage (current) that vibrates at a target resonance frequency is applied to the vibrator 14 without feeding back the actual vibration on the excitation side, the excitation side Even if the vibration differs between the receiving side and the receiving side, it cannot be confirmed, and the vibration of the diaphragm 12 becomes unstable. For example, there are resonance frequencies near 20 kHz, such as 19.19 kHz and 19.32 kHz, which are very close to each other, and may have different vibration states on the excitation side and the reception side. In this case, there is a high possibility that unbalanced vibration is generated because the longitudinal vibration of the portion corresponding to the vibrator does not match the flexural vibration of the diaphragm.

  However, the control device 27 controls the excitation means of the diaphragm 12 by feeding back actual vibrations on the excitation side and the reception side of the diaphragm 12. As a result, it is possible to prevent the excitation side and the receiving side from vibrating at different resonance frequencies, and to vibrate the entire diaphragm 12 efficiently and stably in a fringe mode.

This embodiment has the following effects.
(1) When the diaphragm 12 having a plurality of resonance frequencies is excited by the excitation means and the object is levitated by the radiation pressure of the sound wave from the diaphragm 12, the excitation side vibration for detecting the vibration on the excitation side of the diaphragm 12 is detected. The excitation means of the diaphragm 12 is controlled using the detection signal of the sensor 25 and the detection signal of the receiving-side vibration sensor 26 that detects vibration on the receiving side of the diaphragm 12. Accordingly, the actual vibration states on the excitation side and the reception side of the diaphragm 12 are fed back to control the excitation means of the diaphragm 12. As a result, even if the diaphragm 12 has a plurality of resonance frequencies, it is possible to prevent the vibration on the excitation side and the receiving side from being different, and to vibrate the entire diaphragm 12 efficiently and stably. be able to. Further, the vibration plate 12 can be operated even if there is a temperature change or a change over time without previously obtaining an appropriate vibration condition corresponding to the environmental temperature of the vibration system and a change over time and storing it in the storage device of the control device 27. It is possible to prevent vibration in another vibration mode.

  (2) The diaphragm 12 is excited to generate a standing wave, the receiving side of the diaphragm 12 is supported by the horn 16, and the receiving side vibration sensor 26 is attached to the metal block 19a to which the horn 16 is fixed. Is attached. Therefore, since the receiving side is supported by the horn 16, the configuration is simpler than a configuration in which a vibrator is also provided on the receiving side.

  (3) The diaphragm 12 is vibrated in a stripe mode. Therefore, compared with the case where the diaphragm 12 is vibrated in the lattice mode, noise is suppressed and the diaphragm 12 is vibrated in a stable state.

  (4) The long diaphragm 12 is used for levitating the object 13 by using ultrasonic radiation pressure caused by vibration. Since the diaphragm 12 is vibrated uniformly in the stable state as described above, the object 13 is stably levitated when the object 13 is levitated by the ultrasonic radiation pressure generated by the vibration of the long diaphragm 12. be able to.

  (5) When the vibration state of the diaphragm 12 deviates from the appropriate state, it can be adjusted to the appropriate state by changing at least one of the phase and frequency of the output voltage of the oscillator 22, so the configuration of the control device 27 is simple. Become.

  (6) The diaphragm 12 generates a standing wave to hold the object 13 in a levitation state, and is propelled to move in the longitudinal direction of the diaphragm 12 by compressed air ejected from the nozzle 24 with respect to the object 13 in that state. The object 13 is conveyed in a levitated state by applying a force. Accordingly, the configuration of the excitation means is simpler than the configuration in which traveling waves are generated in the diaphragm 12 and the object 13 is conveyed in a floating state.

(Second Embodiment)
Next, a second embodiment will be described with reference to FIGS. This embodiment is greatly different from the first embodiment in that the diaphragm 12 is excited so as to generate a traveling wave and no applying means for applying a propulsive force to the object 13 is provided. The same parts as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  As shown in FIG. 3, the vibrator 28 is also fastened to the horn 16 fastened to the wave receiving side of the diaphragm 12. The vibrator 28 is configured in the same manner as the vibrator 14 on the excitation side, and the vibrator 28 is connected to a load circuit 29 as an energy conversion means including a resistor R and a coil L. A voltage sensor 30 is connected to the load circuit 29 as a receiving side vibration sensor that detects vibration on the receiving side of the diaphragm 12. The voltage sensor 30 outputs a voltage V2 as a detection signal corresponding to the vibration of the vibrator 28 that is equivalent to the vibration on the receiving side of the diaphragm 12. The output of the voltage sensor 30 is input to the control device 27.

  Based on the detection signals of the excitation-side vibration sensor 25 and the voltage sensor 30, the control device 27 generates a traveling wave and vibrates the diaphragm 12 as a whole in a fringe mode almost uniformly. To control. More specifically, as shown in FIG. 4, control is performed so that the difference between the excitation-side vibration phase and the reception-side vibration phase falls within a predetermined range (for example, 70 to 110 °).

  In this embodiment, the vibration of the diaphragm 12 is transmitted to the receiving-side vibrator 28, and the vibration energy, which is mechanical energy, is converted into electric energy by the piezoelectric elements 17 a and 17 b constituting the vibrator 28. This electrical energy is converted into Joule heat by the resistance R of the load circuit 29 and is dissipated. Therefore, the vibration wave generated in the diaphragm 12 becomes a traveling wave that travels in one direction from the excitation side to the receiving side (in this embodiment, a traveling wave that travels from the vibrator 14 side to the vibrator 28 side), and the object 13 Is conveyed in a floating state from the excitation side to the wave receiving side of the diaphragm 12.

  In the vibrator 14 using a piezoelectric element, it is necessary to excite the vibrator 14 at a resonance frequency in order to vibrate efficiently in a state where the diaphragm 12 generates a standing wave. On the other hand, in order to vibrate the diaphragm 12 in a state in which traveling waves are efficiently generated, it is preferable to excite the vibrator 14 at a frequency slightly shifted from the resonance frequency instead of the resonance frequency. However, when the diaphragm 12 has a plurality of resonance frequencies, when the diaphragm 12 is vibrated by feeding back the vibration state of only one of the excitation side and the reception side, different resonance frequencies are obtained on the excitation side and the reception side. There is a risk of vibration. In this embodiment, the control device 27 grasps the vibration states on the excitation side and the reception side based on the detection signals of the excitation side vibration sensor 25 and the voltage sensor 30, and the diaphragm 12 generates a uniform traveling wave as a whole. The oscillator 22 is controlled as follows. As a result, a uniform traveling wave is generated from the diaphragm 12.

In addition to the same effects as (1) and (3) to (5) of the first embodiment, this embodiment has the following effects.
(7) The control device 27 excites the vibrator 14 so as to generate traveling waves in the diaphragm 12 having a plurality of resonance frequencies. At this time, since the vibration states of the excitation-side vibrator 14 and the receiving-side vibrator 28 are fed back, the control device 27 can be used in the state where the vibration phase difference between the excitation side and the receiving side is optimal. It becomes possible to drive the vibrator 14 at the optimum frequency.

  (8) A voltage sensor 30 for detecting the voltage V2 output from the energy conversion elements (piezo elements 17a and 17b) is used as a receiving-side vibration sensor for detecting the vibration state of the receiving-side vibrator 28. Therefore, the vibration state of the receiving-side vibrator 28 can be easily detected.

  (9) As the vibrators 14 and 28 on the excitation side and the reception side, vibrators having the same configuration including the piezoelectric elements 17a and 17b are used. Therefore, it becomes easy to electrically detect the vibration state of the vibrator 28 on the receiving side.

  (10) The vibration energy, which is mechanical energy, is converted into electrical energy by the piezoelectric elements 17 a and 17 b constituting the receiving-side vibrator 28, and this electrical energy is converted into Joule heat by the resistance R of the load circuit 29. Dissipated. Accordingly, a traveling wave from the excitation side toward the reception side can be easily generated as compared with a configuration in which the vibration energy is not consumed by the load circuit 29.

The embodiment is not limited to the above, and may be configured as follows, for example.
In the second embodiment, instead of providing the load circuit 29 with the voltage sensor 30 as a receiving-side vibration sensor for detecting the receiving-side vibration state of the long diaphragm 12, the same as in the first embodiment. A receiving-side vibration sensor 26 may be provided.

  O The configuration for supporting the diaphragm 12 is not limited to the configuration for supporting at two locations in the longitudinal direction, and may be configured to support at three or more locations. In that case, the diaphragm 12 may be configured to be excited by a plurality of vibrators. For example, as shown in FIG. 5, a horn 15 fixed to the excitation-side vibrator 14 is fastened to the center and one end of the diaphragm 12, and the receiving-side vibration is attached to the other end of the diaphragm 12. The horn 16 fixed to the child 28 may be fastened. In this embodiment, the detection signals (voltages V1a and V1b) of the respective excitation side vibration sensors 25 provided on both vibrators 14 and the detection signals (voltage V2) of the voltage sensor 30 as the reception side vibration sensor are control devices. 27. Then, the control device 27 grasps the vibration state of the diaphragm 12 on each excitation side and the receiving side based on those detection signals, and excites the vibrator 14 so that the diaphragm 12 generates an appropriate traveling wave. A command signal is output to the oscillator 22. In the case of a long diaphragm, the attenuation of vibration is larger than that of a short diaphragm. However, when the diaphragm 12 is excited by a plurality of vibrators 14, the excitation effect is enhanced, and the diaphragm 12 has a desired amplitude. Is vibrated. In addition, the amount of bending when the object 13 having the same weight is levitated is smaller than that of the diaphragm of the conventional device that vibrates while being supported by the two support parts, and the object 13 is stably in the levitated state. Can be transported.

In the case where a standing wave is generated, the diaphragm 12 may be excited by a plurality of vibrators.
When the traveling wave is generated in the vibration plate 12, the load circuit 29 may not consume the electric energy converted from the vibration energy by the piezoelectric elements 17 a and 17 b configuring the receiving-side vibrator 28. In this case, in order to efficiently generate a traveling wave, the phase difference between the vibrations on the excitation side and the reception side of the vibrator is held at a predetermined value, and the output frequency of the oscillator 22 is also appropriately shifted from the resonance frequency by a predetermined amount. It is necessary to set a proper value. However, the vibration state on the receiving side deviates from the proper state by detecting the vibration state on the excitation side and the receiving side with the output of the voltage sensor 30 as the excitation side vibration sensor 25 and the receiving side vibration sensor 26. At this time, the output of the oscillator 22 can be easily controlled so that the phase difference between the excitation side and the reception side becomes an appropriate value.

  ○ When a standing wave is generated in the diaphragm 12 to hold the object 13 in a levitated state, and a propulsive force applying means for applying a propulsive force to the levitated object 13 is provided to convey the object 13 in a levitating state, The propulsion force applying means is not limited to the nozzle 24 that injects compressed gas (for example, compressed air). When conveying a plate-like member that is easily bent as the object 13, a structure that supports both ends of the plate-like member in the width direction and applies a propulsive force to the plate-like member in the carrying direction, such as a rotating roller or endless A belt-like belt may be provided as a propulsive force applying means.

  The object levitating / conveying device 11 is not limited to a configuration in which the diaphragm 12 is vibrated so as to generate only one of a standing wave and a traveling wave. For example, the diaphragm 12 may be configured to be switchable between a state where the diaphragm 12 is excited to generate a traveling wave and a state where the diaphragm 12 is excited to generate a standing wave. For example, as in the second embodiment, the load circuit 29 is connected to the vibrator 28 on the receiving side, and a switch for opening and closing the load circuit 29 is provided in the middle of the wiring connecting the vibrator 28 and the load circuit 29. . In this configuration, the vibration of the diaphragm 12 is transmitted to the vibrator 28 to which the load circuit 29 is connected, and the vibration energy, which is mechanical energy, is converted into electric energy by the piezo elements 17 a and 17 b constituting the vibrator 28. . When the diaphragm 12 is excited while the switch is on, the electrical energy is converted into Joule heat by the resistance R of the load circuit 29 and is dissipated. Therefore, the vibration wave generated in the diaphragm 12 becomes a traveling wave traveling in one direction. Further, when the diaphragm 12 is excited while the switch is off, a standing wave is generated in the diaphragm 12. In this case, not the voltage sensor 30 but the receiving side vibration sensor 26 is provided.

  In the second embodiment, the vibrators 14 and 28 provided at both ends of the diaphragm 12 can be selectively switched and connected to the oscillator 22 and the load circuit 29, respectively, and can be held without being connected to either of them. Constitute. In this case, by switching between the state connected to the oscillator 22 and the state connected to the load circuit 29, the traveling direction of the traveling wave is changed from one end side to the other end side of the diaphragm 12 or from the other end side. It can be changed to one end side. Therefore, when the object 13 is transported in the levitation state, it is easy to brake the object 13 that is moving in the levitation state and stop it at a predetermined position by switching the direction of the traveling wave. Moreover, the conveyance direction of the object 13 can be selected. Furthermore, when one vibrator is connected to the oscillator 22 and the other vibrator is held in a state where it is not connected to either the oscillator 22 or the load circuit 29, a standing wave is generated from the diaphragm 12, and the object 13 is levitated. It can be held at a fixed position in the state.

In the case of using a piezoelectric element, the vibration sensor may be configured so as to be integrated with the vibrator and tightened on the vibration piezoelectric element.
The excitation-side vibration sensor 25 and the reception-side vibration sensor 26 are not limited to contact-type vibration sensors that use piezoelectric elements. For example, a non-contact vibration sensor such as a capacitance vibration sensor or an eddy current vibration sensor may be used. When a non-contact type vibration sensor is used, since the mass of the vibration sensor does not affect the vibration system, the degree of freedom of the arrangement position is increased. Further, the vibration can be detected by disposing it facing the surface of the diaphragm 12.

  In the case where the object 13 to be conveyed is a plate-like member having a wide width and being easily bent, a plurality of units of the diaphragm 12 and the excitation means may be arranged in parallel. In this case, the wide object 13 can be transported in a stable floating state by the plurality of diaphragms 12.

The shape of the horns 15 and 16 is not limited to a flat rectangular parallelepiped shape, and may be a shape with a narrowed tip side such as a columnar shape or a truncated cone shape.
The shape of the object 13 is not limited to a rectangle such as a rectangle, but may be an arbitrary shape such as a triangle, another polygon, or a circle.

The fixing of the diaphragm 12 to the horns 15 and 16 is not limited to fastening with screws, and an adhesive may be used, or may be fixed by brazing or welding.
Inventions (technical ideas) other than the claims described from the embodiments will be described below.

  (1) In the invention according to claim 2, a vibrator having a piezoelectric element on the wave receiving side is fixed via a horn so that the diaphragm generates a traveling wave, and a load circuit is connected to the vibrator. The reception-side vibration sensor is connected to a voltage sensor that detects an output voltage and a phase of the reception-side vibrator.

  (2) In the invention according to claim 2, each vibrator coupled to one end side and the other end side of the diaphragm is configured to be switchably connectable to the oscillator, and the excitation side and the reception side are switched. It is configured to be possible.

  (3) In the invention according to claim 2 and any one of the technical ideas (1) and (2), the diaphragm has the same configuration having piezoelectric elements as vibrators on the excitation side and the reception side The vibrator is used.

  (4) In the invention according to any one of claims 1 to 4 and the technical ideas (1) and (2), the excitation means excites the diaphragm with a plurality of vibrators.

The schematic perspective view of the object levitation conveyance apparatus of 1st Embodiment. Similarly the model side view of an object levitation conveyance apparatus. The schematic perspective view of the object levitation conveyance apparatus of 2nd Embodiment. The graph explaining an effect | action. The schematic perspective view of the object levitation conveyance apparatus of another embodiment. FIG. 6 is a schematic configuration diagram of a conventional vibrator driving power supply device.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 ... Object levitation conveyance apparatus as an object levitation device, 12 ... Diaphragm, 13 ... Object, 14 ... Vibrator which comprises excitation means, 15 ... Similarly horn, 16 ... Horn, 22 ... Oscillator which comprises excitation means, 25 DESCRIPTION OF SYMBOLS Excitation side vibration sensor, 26 ... Reception side vibration sensor, 27 ... Control device, 30 ... Voltage sensor as reception side vibration sensor.

Claims (4)

An object levitation device that excites a diaphragm having a plurality of resonance frequencies by an excitation means and levitates an object by radiation pressure of sound waves from the diaphragm,
Excitation means for the diaphragm using a detection signal of an excitation side vibration sensor for detecting vibration on the excitation side of the diaphragm and a detection signal of a reception side vibration sensor for detecting vibration on the reception side of the diaphragm An object levitation device provided with a control device for controlling. The object levitation apparatus according to claim 1, wherein the diaphragm is excited by a vibrator so as to generate a traveling wave. The vibration plate is excited to generate a standing wave, the receiving side of the diaphragm is supported by a horn, and the receiving side vibration sensor is attached to the horn. Object levitation device. The object levitation apparatus according to claim 1, wherein the diaphragm is vibrated in a stripe mode.

Images