JP2018128255A - Ultrasonic sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ultrasonic sensor, by being mounted on the surface of a reverse side of the bumper of an automobile, especially advantageously used to search for the position of a person or an object present at a position close to the automobile.SOLUTION: Provided is an ultrasonic sensor including the members below and having an exchangeable piezoelectric vibrator: a piezoelectric vibrator removably fixed to the surface of a tabular substrate in an adhered state via or without a buffer layer; a cylindrical restraining material closely arranged on the side face of the piezoelectric vibrator; or a piezoelectric vibrator unit including a cylindrical restraining material closely arranged on the side face of the piezoelectric vibrator and a cylindrical container disposed via an air space around the cylindrical restraining material and having a closed top and an opening at the bottom; a cylindrical wall made from rigid material for housing the piezoelectric vibrator unit in a contactless state, provided with a removable lid at the top, and provided with a junction plane to the tabular substrate at the bottom; and an elastic member inserted between the top face of the piezoelectric vibrator unit and the underside of the lid.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an ultrasonic sensor. The present invention is particularly advantageous for detecting the position of a person or an object that is mounted on the surface of a flat substrate such as a bumper of an automobile and exists in a space opposite to the mounting surface of the ultrasonic sensor. The present invention relates to an ultrasonic sensor that can be used for the above. The present invention also provides a position of a human or an object existing in a space in contact with the surface opposite to the mounting surface of the ultrasonic sensor, including the flat substrate and the ultrasonic sensor mounted on the surface of the flat substrate. It also relates to an ultrasonic detection device that can be advantageously used for detection.

  In order to prevent contact between an automobile and an object such as a human being or other automobiles or various facilities, which is likely to occur during driving or parking work, an ultrasonic sensor is attached to the bumper of the automobile and the ultrasonic wave is installed. The presence of humans and objects by transmitting ultrasonic waves from the sensor toward the space where humans and objects are expected, and then receiving the ultrasonic waves reflected from the humans and objects by the ultrasonic sensor Various ultrasonic detectors used for detecting the position of the sensor have already been developed and are actually used. As an ultrasonic sensor, one having a structure in which a piezoelectric vibrator having an ultrasonic transmission / reception function is built in a casing is generally used.

  As a method of attaching the ultrasonic sensor to the bumper of the automobile, a method of joining and fixing the ultrasonic sensor to the front surface of the bumper (the surface opposite to the surface facing the automobile body), forming a hole in the bumper, There are known a method in which an ultrasonic sensor is mounted in the hole, and a method in which the ultrasonic sensor is bonded and fixed to the back side surface of the bumper (the surface facing the automobile body). Among these, there is no particular problem with the ultrasonic detection system configured by bonding and fixing the ultrasonic sensor to the front surface of the bumper, but there is no ultrasonic problem on the front surface of the bumper. Since the sensor protrudes, an aesthetic problem occurs in the appearance of the bumper. Furthermore, there is a practical problem that the ultrasonic sensor protruding from the bumper surface is easily damaged by contact with an object such as another automobile or a human being. In addition, regarding an ultrasonic detection system configured using a method in which a hole is formed in a bumper and an ultrasonic sensor is mounted in the hole, the formation of the hole in the bumper itself has aesthetic resistance. Also, it is not preferred because it leads to a decrease in the mechanical strength of the bumper.

  On the other hand, an ultrasonic detection system configured by bonding and fixing an ultrasonic sensor to the backside surface of the bumper does not show the presence of the ultrasonic sensor when the automobile is observed from a normal position, and the mechanical strength of the bumper. This is a preferred form because it does not cause the problem of lowering. However, when the ultrasonic wave transmitted from the ultrasonic sensor passes through the bumper and propagates to the front space, it also causes a minute vibration of the bumper, so that the ultrasonic sensor shows a preferable vibration mode and directivity. There is a problem that the signal characteristics of the ultrasonic wave transmitted after adjustment changes due to the passage of the bumper, and the ultrasonic wave transmitted to the space in front of the bumper does not easily exhibit the desired directivity.

  Patent Document 1 discloses a component having a continuous substantially flat member and a surface forming a hole as an acoustic transmission or reception device particularly suitable for use as an auxiliary means for parking. The surface is attached to the flat member around the entire hole, a component that causes a portion of the member to cover the hole, and movement of the portion of the member is converted into an electrical signal; An acoustic transmission or reception device is disclosed, comprising an acoustic transducer attached to the portion so as to be vice versa. And this patent document 1 describes that the acoustic transmission or reception apparatus having the above-described configuration is such that an acoustic signal having a predetermined beam width is transmitted through a member such as a bumper with a relatively low loss. Is seen.

  As described above, the acoustic transmission or reception device described in Patent Document 1 is mainly intended for an ultrasonic detection device configured by mounting an ultrasonic sensor on the back surface of a bumper (bumper bar). The drive bar of the acoustic transducer is bonded to the back surface of the sensor and is attached and fixed by ultrasonic welding around its edge, and the wall thickness of the drive bar is not contacted with the drive bar. A flat member, which is a wall body, is disposed, and is ultrasonically welded to the bumper. In the description shown in Patent Document 1, such a configuration suppresses the vibration of the bumper due to the acoustic energy such as the ultrasonic wave propagated from the drive bar of the acoustic transducer to the bumper, and has a predetermined beam width. It is described that the signal is transmitted through a member such as a bumper with relatively low loss.

  Patent Document 2 discloses an ultrasonic sensor as an ultrasonic sensor capable of ensuring good directivity even when an ultrasonic sensor is housed in a housing and attached to the back surface of a vehicle bumper or a resin portion. A piezoelectric vibrator (ultrasonic vibrator) for transmitting and receiving and housing the piezoelectric vibrator, the piezoelectric vibrator being in contact with the inner surface of the bottom surface portion and being fixed, and the outer surface of the bottom surface portion being A housing that contacts the inner surface of the vehicle bumper or the resin portion, and the housing is in contact with the vehicle bumper or the resin portion and the piezoelectric vibrator at a part of a bottom surface portion of the housing. Forming an ultrasonic transmission portion made of a material different from that of the piezoelectric material and having an intermediate acoustic impedance between the acoustic impedance of the piezoelectric vibrator and the acoustic impedance of the vehicle bumper or resin portion. The transmission and reception of ultrasonic waves, an ultrasonic sensor which is characterized in that through the ultrasonic transmission unit and said vehicle bumper or the resin portion is described.

Japanese National Patent Publication No. 9-500448 JP 2007-142967 A

  As described above, it is preferable that an ultrasonic sensor mounted on a bumper of an automobile is mounted on the back side (inside) of the bumper. However, even if the ultrasonic sensor is mounted on the back side of the bumper, the temperature and humidity are always constant. Performance degradation is likely to occur because it is placed in contact with the changing and severe external environment. Further, the ultrasonic sensor mounted on the bumper vibrates together with the vibration of the bumper during driving of the automobile. For this reason, there is a problem that an ultrasonic sensor, which is a precision instrument, is liable to cause a problem while being mounted on a bumper. If a malfunction occurs in the ultrasonic sensor mounted on the bumper of the car, the bumper on which the ultrasonic sensor is mounted must be replaced or the ultrasonic sensor needs to be repaired. It is uneconomical to replace the bumper every time the occurrence of the problem, and repair of the ultrasonic sensors disclosed in Patent Document 1 and Patent Document 2 mounted on the bumper is not easy.

  Therefore, the inventor of the present invention can easily replace (replace) an ultrasonic sensor bonded to a flat substrate such as a bumper of an automobile when a problem occurs or when adjustment of characteristics is required. Research was conducted for the purpose of developing an ultrasonic sensor that can be used. As a result of the research, an ultrasonic sensor is obtained by combining a unit including a piezoelectric vibrator (piezoelectric vibrator unit) and a unit including a cylindrical wall body made of a rigid material containing the piezoelectric vibrator (cylindrical wall body unit). After the separation, the cylindrical wall unit is bonded and fixed to the surface of a flat substrate such as a bumper. The piezoelectric vibrator unit is fixed to the surface of the flat substrate in a detachable manner. By fixing to the surface of the flat substrate as described above, a failure occurred or the occurrence of the failure was feared without removing the cylindrical wall unit bonded and fixed to the surface of the flat substrate. We obtained new knowledge that an ultrasonic sensor that can easily replace the piezoelectric vibrator unit can be constructed. And based on such new knowledge, it is possible to propagate ultrasonic waves transmitted from the piezoelectric vibrator as ultrasonic waves having high energy efficiency and maintaining favorable directivity beyond the flat substrate. As a result of further research for developing an ultrasonic sensor and an ultrasonic detection device, the present invention has been achieved.

The present invention is an ultrasonic sensor capable of exchanging piezoelectric vibrators, including the following members.
A piezoelectric vibrator fixed in a close contact and detachable manner with or without a buffer layer on a surface of a flat substrate, and a cylindrical restraining material arranged in close contact with a side surface of the piezoelectric vibrator, or A piezoelectric device including a cylindrical restraining member disposed in close contact with a side surface of a piezoelectric vibrator, and a cylindrical container disposed around the tubular restraining material via an air layer and having a closed top and an opening at the bottom. Vibrator unit,
A cylindrical wall body made of a rigid material that houses the piezoelectric vibrator unit in a non-contact state, includes a lid that can be attached to and detached from the top, and a bonding surface to the flat substrate at the bottom; and
An elastic body inserted between the top surface of the piezoelectric vibrator unit and the lower surface of the lid.
In the present specification, “detachable” means that a component can be removed without physical damage to the component.

Preferred embodiments of the ultrasonic sensor of the present invention are described below.
(1) The piezoelectric vibrator is a columnar or disk-shaped piezoelectric ceramic sintered body having an electrode layer on each of a top surface and a bottom surface.
(2) The buffer layer is an acoustic matching layer.
(3) The said cylindrical restraint material is formed from silicone rubber, urethane rubber, or butylene rubber.
(4) The elastic body is a ring-shaped spring or a rubber material molded body.
(5) The piezoelectric vibrator unit is disposed in close contact with the surface of the flat substrate so that the piezoelectric vibrator unit is in a close contact state and detachable with or without a buffer layer interposed therebetween, and the side surface of the piezoelectric vibrator. Including a cylindrical restraint.
(6) The piezoelectric vibrator unit is in close contact with the surface of the flat base plate with or without a buffer layer in a close contact and detachable manner, and is disposed in close contact with the side surface of the piezoelectric vibrator. And a cylindrical container having a closed top and an opening at the bottom, which is disposed around the cylindrical restraining material via an air layer.

The present invention also resides in the following ultrasonic detector equipped with the ultrasonic sensor of the present invention described above.
An ultrasonic detection device comprising the surface of a flat substrate and the ultrasonic sensor of the present invention joined at the bottom surface of a cylindrical wall made of a rigid material, the piezoelectric vibration housed in the ultrasonic sensor Replacement of the piezoelectric vibrator is characterized in that the bottom surface of the piezoelectric vibrator of the slave unit is fixed to the surface of the flat substrate in a close contact state with or without a buffer layer therebetween and detachable. Possible ultrasonic detector.

  The ultrasonic sensor of the present invention can be easily mounted on the surface of a bumper or the like of an automobile, in particular, the back side surface. In particular, even when the ultrasonic sensor is mounted on the back side surface of an automobile bumper, the bumper caused by the ultrasonic vibration transmitted from the piezoelectric vibrator Therefore, the directivity and energy efficiency of the ultrasonic waves transmitted to the front space beyond the bumper are hardly reduced. Furthermore, the ultrasonic sensor of the present invention includes a unit including a piezoelectric vibrator (piezoelectric vibrator unit) and a unit including a cylindrical wall body made of a rigid material that houses the piezoelectric vibrator (cylindrical wall body unit). Because it is configured as a separate transducer exchange type ultrasonic sensor, even when mounted on a flat substrate such as a bumper, a problem occurred without removing the cylindrical wall unit bonded and fixed to the surface of the bumper. Alternatively, there is an advantage that replacement (exchange) of the piezoelectric vibrator unit that is in a state in which the occurrence of a problem is a concern can be easily performed.

It is a schematic diagram showing a typical configuration example of a transducer exchange type ultrasonic sensor of the present invention. It is a schematic diagram which shows the other typical structural example of the vibrator | oscillator exchange type ultrasonic sensor of this invention.

  Next, a configuration example of the transducer exchange type ultrasonic sensor of the present invention will be described with reference to the accompanying drawings.

  FIG. 1 is a schematic diagram (schematic diagram shown in the form of a sectional view) showing a typical configuration example (configuration A) of the transducer-exchangeable ultrasonic sensor of the present invention. The ultrasonic sensor 10 of this configuration A includes a piezoelectric vibrator 11 that is fixed in a close contact and detachable manner on a surface of a flat substrate 16 with or without a buffer layer 13, and a side surface of the piezoelectric vibrator 11. A piezoelectric vibrator unit including a cylindrical constraining member 14 disposed in close contact with the lid, a detachable lid 15 that accommodates the piezoelectric vibrator unit in a non-contact state, and has a flat plate shape at the bottom. A cylindrical wall body 12 made of a rigid material having a bonding surface to the base, and an elastic body 17 inserted between the top surface of the piezoelectric vibrator unit and the lower surface of the lid body 15. .

  In FIG. 1, a transducer-exchangeable ultrasonic sensor 10 according to the present invention is made of a rigid material that houses a unit (piezoelectric transducer unit) including a piezoelectric transducer 11 as a main functional component and the piezoelectric transducer in a non-contact state. The unit including the cylindrical wall body 12 (cylindrical wall body unit) is configured as a basic component. As the piezoelectric vibrator 11, a columnar or disk-shaped piezoelectric ceramic sintered body having electrode layers on the upper surface (top surface) and the lower surface (bottom surface) is generally used. In the present specification, the “columnar” piezoelectric ceramic sintered body means a piezoelectric ceramic sintered body having a shape such as a cylinder, an elliptical column, or a rectangular column having a height of 1 or more with respect to the diameter of the bottom surface. The diameter when the shape of the bottom surface is not a perfect circle means the diameter obtained by converting the area of the bottom surface as the area of the circle. Accordingly, the disk-shaped piezoelectric ceramic sintered body means a piezoelectric ceramic sintered body having a shape such as a disk having a height less than 1 with respect to the diameter of the bottom surface, an elliptical disk-shaped body, or a polygonal disk-shaped body. To do. As the columnar or disk-shaped piezoelectric ceramic sintered body, a columnar or disk-shaped sintered body is usually used, but in order to adjust the directivity of ultrasonic waves generated by the piezoelectric vibrator, it is arranged along the bottom surface. A columnar or disk-shaped sintered body having a square or rectangular cross section may be used.

  Examples of piezoelectric ceramic materials include known piezoelectric ceramic materials such as lead zirconate titanate (PZT), lead titanate, lead zirconate, and barium titanate. The sintered body of the piezoelectric ceramic material may be porous or non-porous. However, considering the performance as a piezoelectric vibrator, particularly excellent frequency characteristics and low acoustic impedance, it is porous. The sintered body is preferably used. As this porous sintered body, a sintered body including pores in an average diameter of 1 to 100 μm in a dispersed state and having a porosity (porosity) of 5 to 50% by volume is preferably used. The use of such a porous ceramic material sintered body as a constituent material of a piezoelectric vibrator is described in Japanese Patent Application Laid-Open No. 2000-119063 (= US Pat. No. 6,111,339). Although not described in the specification, the content described in these documents is the content described in the present specification.

  The sintered body of the ceramic material is formed into a piezoelectric vibrator by attaching electrode layers to the upper and lower surfaces thereof. The electrode layers on the upper and lower surfaces are connected to wiring for applying electrical energy to the ceramic material sintered body to generate ultrasonic waves and for electrically extracting received ultrasonic waves (reflected waves). However, in the accompanying drawings of this specification, in order to avoid complication, the entry of those electrode layers and wirings is omitted.

  Of course, a piezoelectric material made of various materials other than the ceramic material can be used as a constituent material of the piezoelectric vibrator as desired.

  The lower surface (bottom surface) of the piezoelectric vibrator is a soft resin or rubber material, silicone grease, or oily that is effective for facilitating fixing of the piezoelectric vibrator to the surface of a flat substrate such as a bumper. It is preferable to provide a buffer layer 13 formed of a material that is an oily material such as grease. However, the buffer layer 13 is an auxiliary layer for realizing fixation of the piezoelectric vibrator to the surface of the flat substrate, and is for joining the piezoelectric vibrator to the surface of the flat substrate. Therefore, it should not be a layer made of a material that prevents the piezoelectric vibrator from being detached from the surface of the flat substrate by bonding the piezoelectric vibrator to the surface of the flat substrate. As the buffer layer 13, an acoustic matching layer generally used for acoustic matching between the piezoelectric vibrator and another material can be used.

  The piezoelectric vibrator 11 is an elastic cylindrical restraining material formed of a silicon resin (particularly silicone rubber) exhibiting elasticity that covers its side surfaces in a close contact state, a urethane resin (particularly urethane rubber) that exhibits elasticity, or butylene rubber. The piezoelectric vibrator unit is configured by being restrained by 14. The piezoelectric vibrator 11 realizes a stable vibration state of the piezoelectric vibrator 11 by the restraint by the cylindrical restraining material 14, and leaks ultrasonic energy generated by the piezoelectric vibrator 11 from the side face of the piezoelectric vibrator 11. It can be effectively prevented. The cylindrical restraining material 14 is preferably provided not only on the side surface of the piezoelectric vibrator 11 but also on the top surface as seen in FIG.

  Particularly preferable as the material for the cylindrical restraint 14 is excellent elasticity with excellent adhesion to a piezoelectric vibrator (particularly lead zirconate titanate) and good temperature characteristics (that is, little influence of temperature change on various physical properties). It has a silicone rubber. Moreover, it is preferable that the cylindrical restraint material 14 is 2 mm or more in thickness. As a method of covering the piezoelectric vibrator 11 with the cylindrical restraining material 14, a method of covering the piezoelectric vibrator with a restraining material previously formed into a tube shape, or a liquid restraining material around the piezoelectric vibrator using a mold. A method of forming a layer of material is generally used.

  The cylindrical constraining material 14 is preferably formed so as to cover the side surface from the upper end portion to the vicinity of the lower end portion of the piezoelectric vibrator 11 for sufficient expression of the restraining effect. If it covers about 1/2 of the height, preferably about 2/3 of the height, a restraining effect that is practically satisfactory can be obtained. Further, as described above, it is preferable that the cylindrical restraint member 14 is provided not only on the side surface of the piezoelectric vibrator 11 but also on the top surface as seen in FIG.

  The piezoelectric vibrator unit having the piezoelectric vibrator 11 and the cylindrical restraining material 14 as basic components includes a detachable lid 15 at the top and a bonding surface to a flat substrate (eg, bumper) 16 at the bottom. The rigid material-made cylindrical wall body 12 is accommodated in a non-contact state.

  As shown in FIG. 1, the cylindrical wall body 12 made of a rigid material is a base fixing portion having a relatively large wall thickness extending upward from a joint surface (bottom surface of the cylindrical wall body) to the flat base body. And an extension portion having a relatively small wall thickness extending upward from the base fixing portion. Alternatively, the cylindrical wall body 12 made of a rigid material may be formed with the same wall thickness from the bottom to the top. The cylindrical wall body 12 that accommodates the piezoelectric vibrator unit in a non-contact state is formed of a rigid material and has such a structure, so that the cylindrical wall body can be reliably bonded to the flat substrate surface. In addition, the vibration of the flat substrate generated by the vibration of the ultrasonic wave generated by the piezoelectric vibrator 11 and transmitted to the opposite space through the flat substrate (for example, a bumper) is a cylindrical wall body. Therefore, it is possible to effectively confine the ultrasonic directivity. Further, the propagation of the ultrasonic wave to the outside of the ultrasonic sensor through the inside or the surface of the flat substrate 16 is effectively suppressed.

  A removable cover 15 is mounted on the top surface of the cylindrical wall 12 made of a rigid material. For example, the cylindrical wall body 12 and the lid body 15 are mounted by engaging a screw groove or a concave portion and a convex portion respectively provided on the side surface of the top portion of the cylindrical wall body 12 and the inner surface of the flange portion of the lid body 15. It is done by using. The cylindrical wall body 12 is preferably formed from a rigid material, and the lid body 15 is also preferably formed from a rigid material. As the rigid material, a hard resin material or a metal material such as a polyolefin resin typified by polypropylene resin or polyethylene resin, or ABS resin is used.

  An elastic body 17 made of an elastic material such as a coil spring is inserted between the lower surface of the lid body 15 detachably mounted on the top surface of the cylindrical wall body 12 and the piezoelectric vibrator unit. A synthetic resin or metal plate may be interposed between the top surface of the piezoelectric vibrator unit and the elastic body 17. The elastic body 17 functions to realize close contact and fixing of the bottom surface of the piezoelectric vibrator 11 in the piezoelectric vibrator unit to the flat substrate 16. As shown in FIG. 1, a coil spring is usually used as the elastic body 17, but a washer (shim ring) is generally attached above and below the elastic body 17. Or it comprises a leaf spring. Moreover, you may form from polymeric materials, such as rubber materials (for example, silicone rubber) and foamed plastics.

  As is clear from the above description regarding FIG. 1, many of the parts constituting the ultrasonic sensor of the present invention are prepared as parts independent of each other. Among them, the central function is achieved by a piezoelectric vibrator unit including the piezoelectric vibrator 11 (in the ultrasonic sensor shown in FIG. 1, the piezoelectric vibrator 11, the buffer layer 13, and the cylindrical restraining material 14. Unit), a cylindrical wall body unit including a cylindrical wall body 12 and a lid body 15 made of a rigid material, and a pressing force for tightly fixing the bottom surface of the piezoelectric vibrator of the piezoelectric vibrator unit to the surface of the flat substrate. The elastic body 17

  When some trouble occurs in the ultrasonic sensor 10 shown in FIG. 1 (damage of the ultrasonic sensor, abnormal operation, etc.), or when anxiety occurs in the normal operation of the ultrasonic sensor due to aging, etc. After removing the lid 15 at the top of the wall body 12, the piezoelectric vibrator unit housed in the inside is taken out, and a new or normal type piezoelectric vibrator unit whose operation has been confirmed is replaced with a cylindrical wall body. By mounting in the unit, the piezoelectric vibrator unit can be easily replaced.

  FIG. 2 is a schematic diagram (schematic diagram shown in the form of a sectional view) showing another typical configuration example (configuration B) of the transducer-exchangeable ultrasonic sensor of the present invention. The ultrasonic sensor having the configuration B is in close contact with the surface of the flat substrate 16 with or without the buffer layer 13 in a close contact and detachable manner, and in close contact with the side surface of the piezoelectric vibrator 11. A piezoelectric vibrator unit including a cylindrical constraining member 14 disposed and a tubular container 18 disposed around the tubular constraining material via an air layer, the top portion being closed and the bottom portion having an opening; A cylindrical wall 12 made of a rigid material having a detachable lid 15 at the top and containing a joining surface to the flat substrate at the bottom, containing the piezoelectric vibrator unit in a non-contact state; and An elastic body 17 is inserted between the top surface of the piezoelectric vibrator unit and the lower surface of the lid 15. The cylindrical container 18 is usually formed from a synthetic resin material or a metal material.

  The main difference in configuration between the ultrasonic sensor of configuration A in FIG. 1 and the ultrasonic sensor of configuration B in FIG. 2 is in the configuration of the piezoelectric vibrator unit, and this will be described in detail next.

  The piezoelectric vibrator unit of the ultrasonic sensor 10 having the configuration B shown in FIG. 2 includes a piezoelectric vibrator 11, a cylindrical restraining material 14 disposed in close contact with the side surface of the piezoelectric vibrator 11, and air around the tubular restraining material. It includes a cylindrical container 18 disposed through the layers, closed at the top and having an opening at the bottom. The arrangement of the cylindrical container 18 through the air layer around the cylindrical restraining material 14 is, for example, as shown in FIG. 2, forming a flange 14 a at the lower end of the cylindrical restraining material 14, This is done by arranging or joining the lower end of the cylindrical container 18 to the upper surface of the flange 14a. Further, in the ultrasonic sensor 10 having the configuration B shown in FIG. 2, the engagement between the cylindrical wall body 12 made of a rigid material and the lid body 15 is a recess formed on the outer surface of the cylindrical wall body 12 and the lid body 15. This is performed by engagement with a convex portion or hook 15a formed on the inner surface.

  The ultrasonic sensor of the configuration B in FIG. 2 is disadvantageous in that the number of components increases, but an air layer is formed between the cylindrical restraining material 14 and the cylindrical container 18, and this air layer is piezoelectric. There is an advantage that the propagation (leakage) of the ultrasonic wave oscillated from the vibrator 11 to the back surface (upper side surface in FIG. 2) is suppressed.

DESCRIPTION OF SYMBOLS 10 Ultrasonic sensor 11 Piezoelectric vibrator 12 Cylindrical wall body made of rigid material 13 Buffer layer 14 Cylindrical restraint material 15 Cover body 16 Flat substrate (bumper)
17 Elastic body 18 Cylindrical container

Claims (8)

An ultrasonic sensor that can replace the piezoelectric vibrator, including the following members:
A piezoelectric vibrator fixed in a close contact and detachable manner with or without a buffer layer on a surface of a flat substrate, and a cylindrical restraining material arranged in close contact with a side surface of the piezoelectric vibrator, or A piezoelectric device including a cylindrical restraining member disposed in close contact with a side surface of a piezoelectric vibrator, and a cylindrical container disposed around the tubular restraining material via an air layer and having a closed top and an opening at the bottom. Vibrator unit,
A cylindrical wall body made of a rigid material that houses the piezoelectric vibrator unit in a non-contact state, includes a lid that can be attached to and detached from the top, and a bonding surface to the flat substrate at the bottom; and
An elastic body inserted between the top surface of the piezoelectric vibrator unit and the lower surface of the lid.   2. The ultrasonic sensor according to claim 1, wherein the piezoelectric vibrator is a columnar or disk-shaped piezoelectric ceramic sintered body provided with an electrode layer on each of a top surface and a bottom surface.   The ultrasonic sensor according to claim 1, wherein the buffer layer is an acoustic matching layer.   The ultrasonic sensor according to claim 1, wherein the cylindrical restraining material is formed of silicone rubber, urethane rubber, or butylene rubber.   The ultrasonic sensor according to claim 1, wherein the elastic body is a ring-shaped spring or a rubber material molded body.   A piezoelectric vibrator in which the piezoelectric vibrator unit is fixed in a close contact state and detachably with or without a buffer layer on the surface of a flat substrate, and a cylinder in close contact with the side surface of the piezoelectric vibrator The ultrasonic sensor according to claim 1, comprising a constrained material.   A piezoelectric vibrator in which the piezoelectric vibrator unit is fixed in a close contact state and detachably with or without a buffer layer on the surface of a flat substrate, and a cylinder in close contact with the side surface of the piezoelectric vibrator The ultrasonic sensor according to claim 1, further comprising: a cylindrical restraining material and a cylindrical container disposed around the cylindrical restraining material via an air layer, the top portion being closed and the bottom portion having an opening.   An ultrasonic detection apparatus in which the ultrasonic sensor according to claim 1 is joined to the surface of a flat substrate at the bottom surface of a cylindrical wall made of a rigid material, and is housed inside the ultrasonic sensor. Piezoelectric vibrations characterized in that the bottom surface of the piezoelectric vibrator of the piezoelectric vibrator body unit is fixed to the surface of the flat substrate in a close contact state with or without a buffer layer, and detachable Ultrasonic detector that can replace the child.

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