WO2016189812A1 - Ultrasonic device and ultrasonic sensor using same - Google Patents

Ultrasonic device and ultrasonic sensor using same Download PDF

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Publication number
WO2016189812A1
WO2016189812A1 PCT/JP2016/002321 JP2016002321W WO2016189812A1 WO 2016189812 A1 WO2016189812 A1 WO 2016189812A1 JP 2016002321 W JP2016002321 W JP 2016002321W WO 2016189812 A1 WO2016189812 A1 WO 2016189812A1
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WO
WIPO (PCT)
Prior art keywords
case
wall portion
ultrasonic device
arc
thick wall
Prior art date
Application number
PCT/JP2016/002321
Other languages
French (fr)
Japanese (ja)
Inventor
田中　直樹
橋本　雅彦
武田　克
卓也 岩本
佐野　健二
拓司 渡部
Original Assignee
パナソニックＩｐマネジメント株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by パナソニックＩｐマネジメント株式会社 filed Critical パナソニックＩｐマネジメント株式会社
Priority to JP2017520216A priority Critical patent/JP6667080B2/en
Publication of WO2016189812A1 publication Critical patent/WO2016189812A1/en

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/52—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S15/00
    • G01S7/521—Constructional features
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S15/00—Systems using the reflection or reradiation of acoustic waves, e.g. sonar systems
    • G01S15/88—Sonar systems specially adapted for specific applications
    • G01S15/93—Sonar systems specially adapted for specific applications for anti-collision purposes
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R17/00—Piezoelectric transducers; Electrostrictive transducers

Definitions

  • the present disclosure relates to an ultrasonic device that transmits and / or receives ultrasonic waves, and an ultrasonic sensor using the ultrasonic device.
  • FIG. 15A is a perspective view of a conventional ultrasonic device 1.
  • FIG. 15B is a cross-sectional view of the conventional ultrasonic device 1.
  • FIG. 15C is a top view of the case 2 of the conventional ultrasonic device 1.
  • the conventional ultrasonic device 1 includes a bottomed cylindrical case 2, a piezoelectric element 3, a pair of lead wires 5, and a filler 4.
  • the piezoelectric element 3 is installed on the inner bottom surface of the case 2.
  • the filler 4 seals the case 2.
  • the pair of lead wires 5 supplies electric power to the piezoelectric element 3.
  • the ultrasonic device 1 is attached to the rear end of a vehicle, for example, and is used as an ultrasonic sensor that detects an obstacle (object) behind the vehicle.
  • Patent Document 1 is known as prior art document information of this application.
  • the ultrasonic device of the present disclosure includes a bottomed cylindrical case, a piezoelectric element, a lead wire, and a filler.
  • the piezoelectric element is installed on the inner bottom surface of the case.
  • the lead wire is connected to the piezoelectric element.
  • the filler seals the case.
  • the case has a first thin wall portion and a first thick wall portion.
  • the first thin wall portion is formed along the inner wall surface of the case.
  • the first thick wall portion has a first protruding portion that protrudes from the inner wall surface of the case toward the internal space of the case.
  • an ultrasonic sensor of the present disclosure includes the above-described ultrasonic device, a wave transmission circuit, and a housing case.
  • the transmission circuit drives an ultrasonic device and generates ultrasonic waves.
  • the housing case holds the ultrasonic device.
  • FIG. 1A is a perspective view of an ultrasonic device according to an embodiment.
  • FIG. 1B is a cross-sectional view of the ultrasonic device according to the embodiment.
  • FIG. 2A is a top view of the case of the ultrasonic device according to the embodiment.
  • FIG. 2B is a side view of the case of the ultrasonic device according to the embodiment.
  • FIG. 2C is a front view of the case of the ultrasonic device according to the embodiment.
  • FIG. 2D is a perspective view of the case of the ultrasonic device according to the embodiment.
  • FIG. 3 is a cross-sectional view of the case of the ultrasonic device according to the embodiment.
  • FIG. 4A is a block diagram of the ultrasonic sensor in the present embodiment.
  • FIG. 4A is a block diagram of the ultrasonic sensor in the present embodiment.
  • FIG. 4B is a block diagram of another ultrasonic sensor according to the present embodiment.
  • FIG. 4C is a schematic diagram of a vehicle to which the ultrasonic sensor according to the embodiment is attached.
  • FIG. 5 is a diagram illustrating the directivity angle characteristics of the ultrasonic device according to the embodiment.
  • FIG. 6 is a diagram illustrating the directivity angle characteristics of the ultrasonic device according to the embodiment.
  • FIG. 7 is a diagram illustrating the directivity angle characteristics of the ultrasonic device according to the embodiment.
  • FIG. 8 is a diagram illustrating the directivity angle characteristics of the ultrasonic device according to the embodiment.
  • FIG. 9 is a diagram illustrating the directivity angle characteristics of the ultrasonic device according to the embodiment.
  • FIG. 10 is a diagram illustrating the directivity angle characteristics of the ultrasonic device according to the embodiment.
  • FIG. 11 is a diagram illustrating the directivity angle characteristics of the ultrasonic device according to the embodiment.
  • FIG. 12 is a diagram illustrating the directivity angle characteristics of the ultrasonic device according to the embodiment.
  • FIG. 13 is a diagram illustrating the directivity angle characteristics of the ultrasonic device according to the embodiment.
  • FIG. 14 is a diagram illustrating the directivity angle characteristics of the ultrasonic device according to the embodiment.
  • FIG. 15A is a perspective view of a conventional ultrasonic device.
  • FIG. 15B is a cross-sectional view of a conventional ultrasonic device.
  • FIG. 15C is a top view of a case of a conventional ultrasonic device.
  • the conventional ultrasonic device 1 when the conventional ultrasonic device 1 is attached to the rear end of a vehicle, it detects an obstacle over a wide range in the horizontal direction while suppressing unnecessary noise from an object behind the rear and the ground. Therefore, the conventional ultrasonic device 1 is designed so as to ensure a narrow directivity in the vertical direction and to realize a wide directivity in the horizontal direction. However, in order to use it for specific purposes such as detecting an empty space in a parking lot, it is necessary to secure a narrow directivity in the vertical direction and to narrow the directivity in the horizontal direction.
  • the directivity angle characteristics depend on the case size. Specifically, the directivity angle characteristic depends on the outer diameter of the cross section of the case.
  • the directivity angle characteristic depends on the outer diameter M of the cross section of the case 2 (FIG. 15C).
  • the minimum directivity angle in the vertical direction at half value ( ⁇ 6 dB) with respect to the maximum output is about 46 degrees. That is, it is difficult to make the vertical directivity angle smaller than 46 degrees.
  • the minimum horizontal directivity angle at half maximum ( ⁇ 6 dB) with respect to the maximum output is about 70 degrees. That is, it is difficult to make the horizontal directivity angle smaller than 70 degrees.
  • the directivity angle in the vertical direction is 46 degrees and the directivity angle in the horizontal direction is 70 degrees. It is difficult to make.
  • the minimum vertical directivity angle at half maximum ( ⁇ 6 dB) with respect to the maximum output is about 37 degrees. That is, it is difficult to make the vertical directivity angle smaller than 37 degrees.
  • the minimum horizontal directivity angle at half maximum (-6 dB) with respect to the maximum output is about 67 degrees. That is, it is difficult to make the horizontal directivity angle smaller than 67 degrees.
  • the vertical directivity angle is 37 degrees and the vertical directivity angle is 67 degrees. It is difficult to make.
  • the present disclosure provides an ultrasonic device and an ultrasonic sensor that can secure a narrow directivity in the vertical direction and can narrow the directivity in the horizontal direction.
  • FIG. 1A is a perspective view of an ultrasonic device 11 according to an embodiment.
  • FIG. 1B is a cross-sectional view of the ultrasonic device 11 according to the embodiment.
  • a broken line is a hidden line which partially shows the part which is hidden and cannot be seen.
  • the ultrasonic device 11 of the present disclosure includes a bottomed cylindrical case 12, a piezoelectric element 13, a lead wire 14, and a filler 15.
  • the piezoelectric element 13 is installed on the inner bottom surface of the case 12.
  • the lead wire 14 is connected to the piezoelectric element 13.
  • the filler 15 seals the case 12.
  • the case 12 has a first thin wall portion 21A and a first thick wall portion 22A.
  • the first thin wall portion 21 ⁇ / b> A is formed along the inner wall surface of the case 12.
  • the first thick wall portion 22 ⁇ / b> A has a first protruding portion 24 ⁇ / b> A that protrudes from the inner wall surface of the case 12 toward the internal space of the case 12.
  • the case 12 has a bottomed cylindrical shape, and has a bottom portion 16 and a cylindrical portion 17.
  • the case 12 is made of, for example, a metal such as aluminum.
  • the bottom portion 16 is a vibration surface that transmits ultrasonic waves, and has an inner bottom surface 19 and an outer bottom surface 20.
  • the cylindrical portion 17 has a pair of opposed thin wall portions 21 and a pair of opposed thick wall portions 22. That is, in FIG. 1A, the cylinder part 17 has the 1st thin wall part 21A and the 2nd thin wall part 21B.
  • the first thin wall portion 21 ⁇ / b> A and the second thin wall portion 21 ⁇ / b> B are formed along the inner wall surface of the case 12.
  • the cylindrical portion 17 has a first thick wall portion 22A and a second thick wall portion 22B.
  • the first thick wall portion 22 ⁇ / b> A has a first protruding portion 24 ⁇ / b> A that protrudes from the inner wall surface of the case 12 toward the internal space of the case 12.
  • the second thick wall portion 22 ⁇ / b> B has a second protrusion 24 ⁇ / b> B that protrudes from the inner wall surface of the case 12 toward the internal space of the case 12.
  • the first thin wall portion 21A and the second thin wall portion 21B are collectively referred to as the thin wall portion 21.
  • the first thick wall portion 22A and the second thick wall portion 22B are collectively referred to as the thick wall portion 22.
  • the first protrusion 24A and the second protrusion 24B are collectively referred to as the protrusion 24.
  • the thin wall portion 21 is a portion having a relatively thin wall thickness and is substantially arc-shaped and has a substantially constant wall thickness.
  • the thickness of the thin wall portion 21 is within a range of ⁇ 10% or less with respect to the average thickness of the thin wall portion 21.
  • the thick wall portion 22 is thicker than the thin wall portion 21, has a protruding portion 24 that protrudes toward the inner space of the case 12, and has a fan shape that extends from the tip 25 of the protruding portion 24 toward the outer periphery of the case 12. .
  • the inner wall surface of the case 12 in which the first thin wall portion 21A is formed is the first arc 51.
  • the first thick wall portion 22A is the first This is a fan shape formed by a line segment connecting the tip 25A of the projecting portion 24A and both ends of the second arc 52 and the second arc 52.
  • the tip 25A of the first protrusion 24A and the tip 25B of the second protrusion 24B are collectively referred to as the tip 25.
  • the piezoelectric element 13 is a transmission source of ultrasonic vibration fixed to the inner bottom surface 19 of the case 12, and includes a piezoelectric body (not shown) and electrodes (not shown) provided on both sides thereof.
  • the pair of lead wires 14 are formed of a conductor. Electrodes (not shown) are formed on both surfaces of the piezoelectric element 13. At least one of the lead wires 14 is connected to one electrode of the piezoelectric element 13. Electric power is supplied to the piezoelectric element 13 by the pair of lead wires 14.
  • the filler 15 is made of a resin material such as foamed silicon resin, for example, and seals the piezoelectric element 13 inside the case 12.
  • FIG. 2A is a top view of the case 12 of the ultrasonic device 11 according to the embodiment.
  • FIG. 2B is a side view of the case 12 of the ultrasonic device 11 according to the embodiment.
  • FIG. 2C is a front view of the case 12 of the ultrasonic device 11 according to the embodiment.
  • FIG. 2D is a perspective view of the case 12 of the ultrasonic device 11 according to the embodiment.
  • FIG. 3 is a cross-sectional view of the case 12 of the ultrasonic device 11 according to the embodiment.
  • FIG. 3 substantially corresponds to a cross-sectional view of the cylindrical portion 17 of the case 12 when the case 12 is cut along a plane parallel to the inner bottom surface 19.
  • the case 12 has a center point 23. Further, as shown in FIGS. 1A, 2A to 2D, and FIG. 3, in the ultrasonic device 11, the X direction, the Y direction, and the Z direction are defined.
  • a portion where the piezoelectric element 13 is disposed with respect to the inner bottom surface 19 of the case 12 is indicated by a rectangular broken line.
  • the piezoelectric element 13 is arranged so that the center of the inner bottom surface 19 of the case 12 and the center of the piezoelectric element 13 are substantially coincident.
  • the length of the piezoelectric element 13 in the X direction is about 6 mm, and the length in the Y direction is about 8 mm.
  • the dimensions of the case 12 include the outer diameter A of the cylindrical portion 17, the opening length B of the thin wall portion 21, the minimum opening length C of the thick wall portion 22, the wall thickness D of the thin wall portion 21, and the thickness.
  • An angle ⁇ and a tip half angle ⁇ of the protrusion 24 of the thick wall portion 22 are shown.
  • the protruding portion 24 of the thick wall portion 22 has a fan shape that extends from the tip 25 toward the outer periphery of the case 12.
  • the leading end half angle ⁇ of the protruding portion 24 of the thick wall portion 22 is 1 ⁇ 2 of the leading end angle at the leading end 25 of the protruding portion 24 of the thick wall portion 22.
  • the opening length B of the thin wall portion 21 is the opening length in the direction in which the thin wall portion 21 faces (Y direction).
  • the minimum opening length C of the thick wall portion 22 is the minimum opening length in the direction (X direction) in which the thick wall portion 22 faces.
  • the maximum opening length F of the thick wall portion 22 is the maximum opening length in the direction (X direction) in which the thick wall portion 22 faces.
  • the maximum wall thickness E of the thick wall portion 22 is the maximum wall thickness of the thick wall portion 22 in the radial direction toward the center point 23.
  • the width G of the thick wall portion 22 is the width of the thick wall portion 22 in the direction perpendicular to the radial direction.
  • FIG. 4A is a block diagram of the ultrasonic sensor 26 of the present embodiment.
  • FIG. 4B is a block diagram of another ultrasonic sensor 26 of the present embodiment.
  • the ultrasonic sensor 26 includes the ultrasonic device 11, a wave transmission circuit 71, and a housing case 73.
  • the ultrasonic device 11 is used as an ultrasonic transducer.
  • the transmission circuit 71 drives the ultrasonic device 11 to generate ultrasonic waves.
  • the housing case 73 holds the ultrasonic device 11 and the transmission circuit 71.
  • the housing case 73 may hold only the ultrasonic device 11. That is, the housing case 73 only needs to hold at least the ultrasonic device 11.
  • FIG. 4C is a schematic diagram of a vehicle 27 to which the ultrasonic sensor 26 of the present embodiment is attached.
  • the ultrasonic sensor 26 detects the presence of an obstacle around the vehicle 27 and detects the distance to the obstacle by transmitting an ultrasonic wave and receiving the reflected ultrasonic wave.
  • the ultrasonic device 11 is displayed with the X direction and Y direction being horizontal and the Z direction being vertical.
  • the ultrasonic device 11 is installed so that the X direction and the Z direction are substantially horizontal with respect to the ground and the Y direction is substantially vertical.
  • the direction in which ultrasonic waves are transmitted or received is the Z direction.
  • the directivity in the horizontal direction can be narrowed to some extent while ensuring the narrow directivity in the vertical direction.
  • the Z direction may have a slight angle with respect to the horizontal direction of the vehicle 27.
  • the Y direction may have a slight angle with respect to the vertical direction.
  • the direction in which the ultrasonic waves are transmitted or received may be slightly tilted upward or downward from the horizontal.
  • the directivity of the ultrasonic device 11 is the directivity of ultrasonic reception sensitivity when the ultrasonic device 11 is used for reception of ultrasonic waves, and when the ultrasonic device 11 is used for transmission of ultrasonic waves. Directivity of radiation intensity of ultrasonic waves.
  • Table 1 shows the dimensions of the case 12, the characteristic values of directivity, and the evaluation results for Examples 1 to 61 studied in this embodiment.
  • the outer diameter A of the cylindrical portion 17 is 14 mm or 16 mm.
  • the opening length B of the thin wall portion 21 is 13 mm or 15 mm.
  • the wall thickness D of the thin wall portion 21 is 0.5 mm.
  • the minimum opening length C of the thick wall portion 22 is in the range of 6.5 mm to 11 mm, and the maximum wall thickness E of the thick wall portion 22 is in the range of 2.0 mm to 4.5 mm.
  • the tip half angle ⁇ of the protruding portion 24 of the thick wall portion 22 is in the range of 30 degrees or more and 80 degrees or less.
  • the center angle ⁇ of the thin wall portion 21 with respect to the center point 23 is in the range of 74.8 degrees or more and 170.6 degrees or less, and the center angle ⁇ of the thick wall portion 22 with respect to the center point 23 is 9.4 degrees or more. , 105.2 degrees or less.
  • Table 1 shows the dimensions of the case 12 and the vertical and horizontal directivity angles at half-value ( ⁇ 6 dB) with respect to the maximum output when ultrasonic radiation is performed.
  • An example in which directivity characteristics are good is “G (Good)”, and an example in which directivity characteristics are not good is “NG (No Good)”.
  • the vertical direction angle is 46 degrees or less and the horizontal direction angle is 70 degrees or less.
  • the directivity angle is a value in the case of ⁇ 6 dB which is a half value with respect to the maximum output. That is, as shown in (Table 1), when the outer diameter A is 14.0 mm, the directivity angle characteristics are good in Examples 7, 8, 15, 16, 17, 22, 23, 24, 25, 29, 30. , 31.
  • the vertical direction angle is 37 degrees or less and the horizontal direction angle is 67 degrees or less.
  • the directivity angle is a value in the case of ⁇ 6 dB which is a half value with respect to the maximum output. That is, as shown in (Table 1), when the outer diameter A is 16.0 mm, Examples 34, 35, 41, 42, 48, 54, and 55 have good directivity characteristics.
  • 5 to 14 are diagrams showing directivity characteristics of the ultrasonic device 11 according to the embodiment. 5 to 14, the horizontal axis represents the tip half angle ⁇ of the protrusion 24, and the vertical axis represents the directivity angle in the case of ⁇ 6 dB which is a half value with respect to the maximum output. 5 to 14 also show the case where the tip half angle ⁇ of the protrusion 24 is 90 degrees. This shows, as a comparative example, the characteristics of the conventional ultrasonic device 1 in which the protruding portion 24 does not exist. In the characteristic diagrams of FIGS. 5 to 14, an excellent range of the directivity angle characteristic is indicated by an arrow.
  • FIG. 5 shows a case where the outer diameter A is 14 mm and the minimum opening length C is 6.5 mm.
  • FIG. 6 shows a case where the outer diameter A is 14 mm and the minimum opening length C is 7.0 mm.
  • FIG. 7 shows a case where the outer diameter A is 14 mm and the minimum opening length C is 8.0 mm.
  • FIG. 8 shows a case where the outer diameter A is 14 mm and the minimum opening length C is 9.0 mm.
  • FIG. 9 shows a case where the outer diameter A is 14 mm and the minimum opening length C is 10.0 mm.
  • FIG. 10 shows a case where the outer diameter A is 16 mm and the minimum opening length C is 7.0 mm.
  • FIG. 11 shows a case where the outer diameter A is 16 mm and the minimum opening length C is 8.0 mm.
  • FIG. 12 shows a case where the outer diameter A is 16 mm and the minimum opening length C is 9.0 mm.
  • FIG. 13 shows a case where the outer diameter A is 16 mm and the minimum opening length C is 10.0 mm.
  • FIG. 14 shows a case where the outer diameter A is 16 mm and the minimum opening length C is 11.0 mm.
  • a good range of the directivity angle characteristic is a range where the tip half angle ⁇ of the protrusion 24 is from 25 degrees to 38 degrees.
  • a favorable range of the directivity angle characteristic is a range where the tip half angle ⁇ of the protrusion 24 is from 35 degrees to 65 degrees.
  • a good range of the directivity angle characteristic is a range in which the tip half angle ⁇ of the protrusion 24 is from 45 degrees to 85 degrees.
  • a good range of the directivity angle characteristic is a range in which the tip half angle ⁇ of the protrusion 24 is from 55 degrees to 85 degrees.
  • a favorable range of the directivity angle characteristic is a range where the tip half angle ⁇ of the protrusion 24 is 45 degrees to 65 degrees.
  • a favorable range of the directivity angle characteristic is a range where the tip half angle ⁇ of the protrusion 24 is 55 degrees to 75 degrees.
  • a favorable range of the directivity angle characteristic is a range where the tip half angle ⁇ of the protrusion 24 is from 65 degrees to 75 degrees.
  • a good range of the directivity angle characteristic is a range in which the tip half angle ⁇ of the protrusion 24 is from 65 degrees to 85 degrees.
  • the ultrasonic device 11 of the present embodiment has the piezoelectric element 13 on the inner bottom surface 19 of the bottomed cylindrical case 12.
  • the cylindrical portion 17 of the case 12 has a substantially arc-shaped thin wall portion 21 with the inner bottom surface 19 centering on the center point 23 of the case 12 and a thin wall portion 21 in a cross section parallel to the inner bottom surface 19 of the case 12.
  • a thick wall portion 22 provided with a protruding portion 24 whose inner wall surface protrudes toward the internal space of the case 12.
  • an ultrasonic sensor 26 equipped with the ultrasonic device 11 as an ultrasonic transducer on a vehicle 27 and using it for detecting an obstacle, the influence of reflection from a road surface or reflection from a ceiling of a garage or the like.
  • the detection with reduced directivity in the horizontal direction is possible. That is, it is possible to detect an empty space that is about the parking width of the vehicle 27 in a parking lot or the like.
  • the ultrasonic device 11 of the present embodiment has the piezoelectric element 13 on the inner bottom surface 19 of the bottomed cylindrical case 12.
  • the cylindrical portion 17 of the case 12 has a thin wall portion 21 having a substantially constant wall thickness in a cross section parallel to the inner bottom surface 19 of the case 12, and an inner side surface that is thicker than the thin wall portion 21 and is inside the case 12.
  • a thick wall portion 22 provided with a protruding portion 24 protruding toward the space.
  • an ultrasonic sensor 26 equipped with the ultrasonic device 11 as an ultrasonic transducer on a vehicle 27 and using it for detecting an obstacle, the influence of reflection from a road surface or reflection from a ceiling of a garage or the like.
  • the detection with reduced directivity in the horizontal direction is possible. That is, it is possible to detect an empty space that is about the parking width of the vehicle 27 in a parking lot or the like.
  • the case 12 preferably has a pair of opposed thin wall portions 21 and a pair of opposed thick wall portions 22. That is, in the cross section parallel to the inner bottom surface of the case 12, the first thin wall portion 21A and the second thin wall portion 21B are opposed to each other, and the first thick wall portion 22A and the second thick wall portion. 22B is opposed to each other. Further, the first thick wall portion 22 ⁇ / b> A is formed symmetrically with the second thick wall portion 22 ⁇ / b> B with respect to the center point 23 of the inner bottom surface of the case 12.
  • the ultrasonic device 11 can more sufficiently control the directivity in the X direction and the directivity in the Y direction, and can narrow the directivity in the X direction while sufficiently securing the narrow directivity in the Y direction. It becomes possible.
  • the central angle ⁇ (first central angle) of the thin wall portion 21 with respect to the central point 23 of the case 12 is larger than the central angle ⁇ (second central angle) of the thick wall portion 22 with respect to the central point 23 of the case 12. It is preferable. That is, in the cross section parallel to the inner bottom surface of the case 12, the inner wall surface (the outer wall surface of the first thin wall portion 21A) of the case 12 in which the first thin wall portion 21A is formed is defined as the first arc 51.
  • the first arc 51 with respect to the center point 23 of the case 12
  • the first center angle ⁇ is preferably larger than the second center angle ⁇ of the second arc 52 with respect to the center point 23 of the case 12.
  • the first arc 51 is preferably longer than the second arc 52.
  • the ultrasonic device 11 can effectively narrow the directivity in the X direction while sufficiently securing the narrow directivity in the Y direction.
  • an ultrasonic sensor 26 equipped with the ultrasonic device 11 as an ultrasonic transducer on a vehicle 27 and using it for detecting an obstacle, the influence of reflection from a road surface or reflection from a ceiling of a garage or the like.
  • the thick wall portion 22 preferably has a fan shape that extends from the tip 25 of the protruding portion 24 toward the outer periphery of the case 12. That is, the first thick wall portion 22A has a fan shape formed by two line segments connecting the tip 25A of the first protruding portion 24A and both ends of the second arc 52, and the second arc 52. Is preferred. With this configuration, the ultrasonic device 11 can satisfactorily control the directivity in the X direction and the Y direction.
  • the central angle ⁇ of the thin wall portion 21 with respect to the center point 23 of the case 12 is preferably set to 100 degrees or more and 155 degrees or less. That is, the first central angle ⁇ of the first arc 51 with respect to the central point 23 of the case 12 is preferably 100 degrees or more and 155 degrees or less.
  • the opening length connecting the tips 25 of the protruding portions 24 of the opposing thick wall portions 22 is the outer diameter A of the case 12 (the outer diameter A of the cylindrical portion 17). It is preferably 0.35 times or more and 0.8 times or less. Further, the thickness D of the thin wall portion 21 is preferably 0.02 times or more and 0.06 times or less of the outer diameter A of the case 12. That is, in the cross section parallel to the inner bottom surface of the case 12, the tip 25A (first tip) of the first protrusion 24A of the first thick wall portion 22A and the second protrusion of the second thick wall portion 22B.
  • the distance between the tip 24B (second tip) of the portion 24B is preferably 0.35 times or more and 0.8 times or less of the outer diameter A of the case 12. Furthermore, the thickness of the first thin wall portion 21A is preferably 0.02 times or more and 0.06 times or less the outer diameter A of the case 12.
  • the ultrasonic device 11 it is preferable to arrange the thin wall portion 21 in the vertical direction and the thick wall portion 22 to the left and right.
  • the bottom of the case 12 is installed so as to face the object, the tip 25A of the first protrusion 24A of the first thick wall 22A, and the second protrusion 24B of the second thick wall 22B.
  • the line segment connecting the distal end 25B of the lens is arranged so as to correspond to the horizontal direction.
  • the thickness of the thin wall portion 21 is substantially constant.
  • the thickness is not necessarily constant.
  • the thickness of the thin wall portion 21 may be inclined.
  • the ultrasonic device and the ultrasonic sensor of the present disclosure can narrow the directivity in the horizontal direction while ensuring the narrow directivity in the vertical direction.
  • the ultrasonic device and the ultrasonic sensor according to the present disclosure are useful as a detector for detecting an object existing near a vehicle, for example.

Abstract

The disclosed ultrasonic device is equipped with a cylindrical, floor-equipped case, a piezoelectric element, a lead wire, and a filler material. The piezoelectric element is provided on the inner floor surface of the case. The lead wire is connected to the piezoelectric element. The filler material seals the case. The case has a first thin wall section and a first thick wall section. The first thin wall section is formed along the inner wall surface of the case. The first thick wall section has a first projection that projects toward the interior space of the case from the inner wall surface of the case.

Description

超音波デバイスとこれを用いた超音波センサUltrasonic device and ultrasonic sensor using the same
　本開示は、超音波の送波または受波、あるいはその両方を行なう超音波デバイスとこれを用いた超音波センサに関する。 The present disclosure relates to an ultrasonic device that transmits and / or receives ultrasonic waves, and an ultrasonic sensor using the ultrasonic device.
　図１５Ａは、従来の超音波デバイス１の斜視図である。図１５Ｂは、従来の超音波デバイス１の断面図である。図１５Ｃは、従来の超音波デバイス１のケース２の上面図である。従来の超音波デバイス１は、有底筒状のケース２と、圧電素子３と、一対のリード線５と、充填材４とを有する。圧電素子３は、ケース２の内底面に設置されている。充填材４は、ケース２を封止する。一対のリード線５は、圧電素子３に電力を供給する。超音波デバイス１は、例えば、車両の後端に取り付けられて、車両後方の障害物（対象物）を検出する超音波センサとして用いられる。なお、この出願の先行技術文献情報としては、例えば、特許文献１が知られている。 FIG. 15A is a perspective view of a conventional ultrasonic device 1. FIG. 15B is a cross-sectional view of the conventional ultrasonic device 1. FIG. 15C is a top view of the case 2 of the conventional ultrasonic device 1. The conventional ultrasonic device 1 includes a bottomed cylindrical case 2, a piezoelectric element 3, a pair of lead wires 5, and a filler 4. The piezoelectric element 3 is installed on the inner bottom surface of the case 2. The filler 4 seals the case 2. The pair of lead wires 5 supplies electric power to the piezoelectric element 3. The ultrasonic device 1 is attached to the rear end of a vehicle, for example, and is used as an ultrasonic sensor that detects an obstacle (object) behind the vehicle. For example, Patent Document 1 is known as prior art document information of this application.
特開２００１－１３２３９号公報JP 2001-13239 A
　本開示の超音波デバイスは、有底筒状のケースと、圧電素子と、リード線と、充填材と、を備えている。圧電素子は、ケースの内底面に設置されている。リード線は、圧電素子に接続されている。充填材は、ケースを封止している。ケースは、第１の薄壁部と、第１の厚壁部と、を有する。第１の薄壁部は、ケースの内壁面に沿って形成されている。第１の厚壁部は、ケースの内壁面からケースの内部空間に向かって突出した第１の突出部を有している。 The ultrasonic device of the present disclosure includes a bottomed cylindrical case, a piezoelectric element, a lead wire, and a filler. The piezoelectric element is installed on the inner bottom surface of the case. The lead wire is connected to the piezoelectric element. The filler seals the case. The case has a first thin wall portion and a first thick wall portion. The first thin wall portion is formed along the inner wall surface of the case. The first thick wall portion has a first protruding portion that protrudes from the inner wall surface of the case toward the internal space of the case.
　また、本開示の超音波センサは、上記の超音波デバイスと、送波回路と、ハウジングケースと、を備えている。送波回路は、超音波デバイスを駆動し、超音波を発生させる。ハウジングケースは、超音波デバイスを保持する。 Also, an ultrasonic sensor of the present disclosure includes the above-described ultrasonic device, a wave transmission circuit, and a housing case. The transmission circuit drives an ultrasonic device and generates ultrasonic waves. The housing case holds the ultrasonic device.
図１Ａは、実施の形態における超音波デバイスの斜視図である。FIG. 1A is a perspective view of an ultrasonic device according to an embodiment. 図１Ｂは、実施の形態における超音波デバイスの断面図である。FIG. 1B is a cross-sectional view of the ultrasonic device according to the embodiment. 図２Ａは、実施の形態における超音波デバイスのケースの上面図である。FIG. 2A is a top view of the case of the ultrasonic device according to the embodiment. 図２Ｂは、実施の形態における超音波デバイスのケースの側面図である。FIG. 2B is a side view of the case of the ultrasonic device according to the embodiment. 図２Ｃは、実施の形態における超音波デバイスのケースの正面図である。FIG. 2C is a front view of the case of the ultrasonic device according to the embodiment. 図２Ｄは、実施の形態における超音波デバイスのケースの斜視図である。FIG. 2D is a perspective view of the case of the ultrasonic device according to the embodiment. 図３は、実施の形態における超音波デバイスのケースの横断面図である。FIG. 3 is a cross-sectional view of the case of the ultrasonic device according to the embodiment. 図４Ａは、本実施の形態における超音波センサのブロック図である。FIG. 4A is a block diagram of the ultrasonic sensor in the present embodiment. 図４Ｂは、本実施の形態の他の超音波センサのブロック図である。FIG. 4B is a block diagram of another ultrasonic sensor according to the present embodiment. 図４Ｃは、実施の形態における超音波センサを取り付けた車両の模式図である。FIG. 4C is a schematic diagram of a vehicle to which the ultrasonic sensor according to the embodiment is attached. 図５は、実施の形態における超音波デバイスの指向角特性を示す図である。FIG. 5 is a diagram illustrating the directivity angle characteristics of the ultrasonic device according to the embodiment. 図６は、実施の形態における超音波デバイスの指向角特性を示す図である。FIG. 6 is a diagram illustrating the directivity angle characteristics of the ultrasonic device according to the embodiment. 図７は、実施の形態における超音波デバイスの指向角特性を示す図である。FIG. 7 is a diagram illustrating the directivity angle characteristics of the ultrasonic device according to the embodiment. 図８は、実施の形態における超音波デバイスの指向角特性を示す図である。FIG. 8 is a diagram illustrating the directivity angle characteristics of the ultrasonic device according to the embodiment. 図９は、実施の形態における超音波デバイスの指向角特性を示す図である。FIG. 9 is a diagram illustrating the directivity angle characteristics of the ultrasonic device according to the embodiment. 図１０は、実施の形態における超音波デバイスの指向角特性を示す図である。FIG. 10 is a diagram illustrating the directivity angle characteristics of the ultrasonic device according to the embodiment. 図１１は、実施の形態における超音波デバイスの指向角特性を示す図である。FIG. 11 is a diagram illustrating the directivity angle characteristics of the ultrasonic device according to the embodiment. 図１２は、実施の形態における超音波デバイスの指向角特性を示す図である。FIG. 12 is a diagram illustrating the directivity angle characteristics of the ultrasonic device according to the embodiment. 図１３は、実施の形態における超音波デバイスの指向角特性を示す図である。FIG. 13 is a diagram illustrating the directivity angle characteristics of the ultrasonic device according to the embodiment. 図１４は、実施の形態における超音波デバイスの指向角特性を示す図である。FIG. 14 is a diagram illustrating the directivity angle characteristics of the ultrasonic device according to the embodiment. 図１５Ａは、従来の超音波デバイスの斜視図である。FIG. 15A is a perspective view of a conventional ultrasonic device. 図１５Ｂは、従来の超音波デバイスの断面図である。FIG. 15B is a cross-sectional view of a conventional ultrasonic device. 図１５Ｃは、従来の超音波デバイスのケースの上面図である。FIG. 15C is a top view of a case of a conventional ultrasonic device.
　従来の超音波デバイス１は、例えば車両の後端に取り付けた際に、後上方の物体や地面からの不要なノイズを抑制しつつ水平方向に広い範囲にわたって障害物を検出する。そのために、従来の超音波デバイス１は、垂直方向の狭指向性を確保し、かつ、水平方向に広指向性を実現できるように設計されている。しかし、駐車場の空きスペースを検出するなどの特定用途に使用するためには、垂直方向の狭指向性を確保し、かつ、水平方向の指向性も狭める必要がある。 For example, when the conventional ultrasonic device 1 is attached to the rear end of a vehicle, it detects an obstacle over a wide range in the horizontal direction while suppressing unnecessary noise from an object behind the rear and the ground. Therefore, the conventional ultrasonic device 1 is designed so as to ensure a narrow directivity in the vertical direction and to realize a wide directivity in the horizontal direction. However, in order to use it for specific purposes such as detecting an empty space in a parking lot, it is necessary to secure a narrow directivity in the vertical direction and to narrow the directivity in the horizontal direction.
　また、指向角特性は、ケースの大きさに依存する。詳しく言えば、指向角特性は、ケースの横断面の外径に依存する。例えば、従来の超音波デバイス１において、指向角特性はケース２の横断面の外径Ｍに依存する（図１５Ｃ）。外径Ｍが１４．０ｍｍの場合、最大出力に対する半値（－６ｄＢ）における垂直方向の指向角の最小は、約４６度である。すなわち、垂直方向の指向角を４６度よりも小さくするのは困難である。そして、垂直方向の指向角を４６度にすると、最大出力に対する半値（－６ｄＢ）における水平方向の指向角の最小は約７０度となる。すなわち、水平方向の指向角を７０度よりも小さくするのは困難である。要するに、従来の超音波デバイス１において、ケース２の外径Ｍが１４．０ｍｍの場合、垂直方向の指向角が４６度で、かつ、水平方向の指向角が７０度が限界であり、それ以下にするのは困難である。 Also, the directivity angle characteristics depend on the case size. Specifically, the directivity angle characteristic depends on the outer diameter of the cross section of the case. For example, in the conventional ultrasonic device 1, the directivity angle characteristic depends on the outer diameter M of the cross section of the case 2 (FIG. 15C). When the outer diameter M is 14.0 mm, the minimum directivity angle in the vertical direction at half value (−6 dB) with respect to the maximum output is about 46 degrees. That is, it is difficult to make the vertical directivity angle smaller than 46 degrees. When the vertical directivity angle is 46 degrees, the minimum horizontal directivity angle at half maximum (−6 dB) with respect to the maximum output is about 70 degrees. That is, it is difficult to make the horizontal directivity angle smaller than 70 degrees. In short, in the conventional ultrasonic device 1, when the outer diameter M of the case 2 is 14.0 mm, the directivity angle in the vertical direction is 46 degrees and the directivity angle in the horizontal direction is 70 degrees. It is difficult to make.
　また、外径Ｍが１６．０ｍｍの場合、最大出力に対する半値（－６ｄＢ）における垂直方向の指向角の最小は、約３７度である。すなわち、垂直方向の指向角を３７度よりも小さくするのは困難である。そして、垂直方向の指向角を３７度にすると、最大出力に対する半値（－６ｄＢ）における水平方向の指向角の最小は約６７度となる。すなわち、水平方向の指向角を６７度よりも小さくするのは困難である。要するに、従来の超音波デバイス１において、ケース２の外径Ｍが１６．０ｍｍの場合、垂直方向の指向角が３７度で、かつ、垂直方向の指向角が６７度が限界であり、それ以下にするのは困難である。 When the outer diameter M is 16.0 mm, the minimum vertical directivity angle at half maximum (−6 dB) with respect to the maximum output is about 37 degrees. That is, it is difficult to make the vertical directivity angle smaller than 37 degrees. When the vertical directivity angle is 37 degrees, the minimum horizontal directivity angle at half maximum (-6 dB) with respect to the maximum output is about 67 degrees. That is, it is difficult to make the horizontal directivity angle smaller than 67 degrees. In short, in the conventional ultrasonic device 1, when the outer diameter M of the case 2 is 16.0 mm, the vertical directivity angle is 37 degrees and the vertical directivity angle is 67 degrees. It is difficult to make.
　本開示は、垂直方向の狭指向性を確保し、かつ、水平方向の指向性を狭くできる超音波デバイスおよび超音波センサを提供する。 The present disclosure provides an ultrasonic device and an ultrasonic sensor that can secure a narrow directivity in the vertical direction and can narrow the directivity in the horizontal direction.
　図１Ａは、実施の形態における超音波デバイス１１の斜視図である。図１Ｂは、実施の形態における超音波デバイス１１の断面図である。図１Ａにおいて、破線は隠れて見えない部分を部分的に示す隠れ線である。 FIG. 1A is a perspective view of an ultrasonic device 11 according to an embodiment. FIG. 1B is a cross-sectional view of the ultrasonic device 11 according to the embodiment. In FIG. 1A, a broken line is a hidden line which partially shows the part which is hidden and cannot be seen.
　本開示の超音波デバイス１１は、有底筒状のケース１２と、圧電素子１３と、リード線１４と、充填材１５と、を備えている。圧電素子１３は、ケース１２の内底面に設置されている。リード線１４は、圧電素子１３に接続されている。充填材１５は、ケース１２を封止している。ケース１２は、第１の薄壁部２１Ａと、第１の厚壁部２２Ａと、を有する。第１の薄壁部２１Ａは、ケース１２の内壁面に沿って形成されている。第１の厚壁部２２Ａは、ケース１２の内壁面からケース１２の内部空間に向かって突出した第１の突出部２４Ａを有している。 The ultrasonic device 11 of the present disclosure includes a bottomed cylindrical case 12, a piezoelectric element 13, a lead wire 14, and a filler 15. The piezoelectric element 13 is installed on the inner bottom surface of the case 12. The lead wire 14 is connected to the piezoelectric element 13. The filler 15 seals the case 12. The case 12 has a first thin wall portion 21A and a first thick wall portion 22A. The first thin wall portion 21 </ b> A is formed along the inner wall surface of the case 12. The first thick wall portion 22 </ b> A has a first protruding portion 24 </ b> A that protrudes from the inner wall surface of the case 12 toward the internal space of the case 12.
　ケース１２は、有底筒状の形状を有し、底部１６と筒部１７とを有する。ケース１２は、例えばアルミニウムなどの金属などで形成されている。底部１６は超音波を発信する振動面であり、内底面１９と外底面２０とを有する。筒部１７は、対向した一対の薄壁部２１と、対向した一対の厚壁部２２とを有する。すなわち、図１Ａにおいて、筒部１７は、第１の薄壁部２１Ａと、第２の薄壁部２１Ｂとを有する。第１の薄壁部２１Ａと、第２の薄壁部２１Ｂは、ケース１２の内壁面に沿って形成されている。さらに、筒部１７は、第１の厚壁部２２Ａと、第２の厚壁部２２Ｂとを有する。第１の厚壁部２２Ａは、ケース１２の内壁面からケース１２の内部空間に向かって突出した第１の突出部２４Ａを有する。第２の厚壁部２２Ｂは、ケース１２の内壁面からケース１２の内部空間に向かって突出した第２の突出部２４Ｂを有する。第１の薄壁部２１Ａと、第２の薄壁部２１Ｂとを総称して薄壁部２１とする。第１の厚壁部２２Ａと、第２の厚壁部２２Ｂとを総称して厚壁部２２とする。第１の突出部２４Ａと、第２の突出部２４Ｂとを総称して突出部２４とする。 The case 12 has a bottomed cylindrical shape, and has a bottom portion 16 and a cylindrical portion 17. The case 12 is made of, for example, a metal such as aluminum. The bottom portion 16 is a vibration surface that transmits ultrasonic waves, and has an inner bottom surface 19 and an outer bottom surface 20. The cylindrical portion 17 has a pair of opposed thin wall portions 21 and a pair of opposed thick wall portions 22. That is, in FIG. 1A, the cylinder part 17 has the 1st thin wall part 21A and the 2nd thin wall part 21B. The first thin wall portion 21 </ b> A and the second thin wall portion 21 </ b> B are formed along the inner wall surface of the case 12. Further, the cylindrical portion 17 has a first thick wall portion 22A and a second thick wall portion 22B. The first thick wall portion 22 </ b> A has a first protruding portion 24 </ b> A that protrudes from the inner wall surface of the case 12 toward the internal space of the case 12. The second thick wall portion 22 </ b> B has a second protrusion 24 </ b> B that protrudes from the inner wall surface of the case 12 toward the internal space of the case 12. The first thin wall portion 21A and the second thin wall portion 21B are collectively referred to as the thin wall portion 21. The first thick wall portion 22A and the second thick wall portion 22B are collectively referred to as the thick wall portion 22. The first protrusion 24A and the second protrusion 24B are collectively referred to as the protrusion 24.
　薄壁部２１は、壁厚が相対的に薄い部分であり、略円弧状で略一定の壁厚を有している。ここで、薄壁部２１の厚さは、薄壁部２１の平均の厚さに対して、±１０％以下の範囲である。 The thin wall portion 21 is a portion having a relatively thin wall thickness and is substantially arc-shaped and has a substantially constant wall thickness. Here, the thickness of the thin wall portion 21 is within a range of ± 10% or less with respect to the average thickness of the thin wall portion 21.
　厚壁部２２は、薄壁部２１よりも厚く、ケース１２の内側空間に向かって突出した突出部２４を有し、突出部２４の先端２５からケース１２の外周に向かって広がる扇形状を有する。 The thick wall portion 22 is thicker than the thin wall portion 21, has a protruding portion 24 that protrudes toward the inner space of the case 12, and has a fan shape that extends from the tip 25 of the protruding portion 24 toward the outer periphery of the case 12. .
　言いかえれば、ケース１２の内底面に平行な断面において、第１の薄壁部２１Ａが形成されたケース１２の内壁面（第１の薄壁部２１Ａの外壁面）を第１の円弧５１とし、第１の厚壁部２２Ａが形成されたケース１２の内壁面（第１の厚壁部２２Ａの外壁面）を第２の円弧５２とした場合、第１の厚壁部２２Ａは、第１の突出部２４Ａの先端２５Ａと第２の円弧５２の両端を結ぶ線分と、第２の円弧５２と、で形成される扇形状である。ここで、第１の突出部２４Ａの先端２５Ａと、第２の突出部２４Ｂの先端２５Ｂとを総称して先端２５とする。 In other words, in the cross section parallel to the inner bottom surface of the case 12, the inner wall surface of the case 12 in which the first thin wall portion 21A is formed (the outer wall surface of the first thin wall portion 21A) is the first arc 51. When the inner wall surface of the case 12 in which the first thick wall portion 22A is formed (the outer wall surface of the first thick wall portion 22A) is the second arc 52, the first thick wall portion 22A is the first This is a fan shape formed by a line segment connecting the tip 25A of the projecting portion 24A and both ends of the second arc 52 and the second arc 52. Here, the tip 25A of the first protrusion 24A and the tip 25B of the second protrusion 24B are collectively referred to as the tip 25.
　圧電素子１３は、ケース１２の内底面１９に固定された超音波振動の発信源であり、圧電体（図示せず）と、その両面に設けられた電極（図示せず）とを有する。 The piezoelectric element 13 is a transmission source of ultrasonic vibration fixed to the inner bottom surface 19 of the case 12, and includes a piezoelectric body (not shown) and electrodes (not shown) provided on both sides thereof.
　一対のリード線１４は、導体で形成されている。圧電素子１３の両面には電極（図示せず）が形成されている。リード線１４の少なくとも一方は、圧電素子１３の一方の電極に接続されている。一対のリード線１４により、圧電素子１３に電力が供給される。 The pair of lead wires 14 are formed of a conductor. Electrodes (not shown) are formed on both surfaces of the piezoelectric element 13. At least one of the lead wires 14 is connected to one electrode of the piezoelectric element 13. Electric power is supplied to the piezoelectric element 13 by the pair of lead wires 14.
　充填材１５は、例えば発泡シリコン樹脂などの樹脂材料などからなり、ケース１２の内部において圧電素子１３を封止する。 The filler 15 is made of a resin material such as foamed silicon resin, for example, and seals the piezoelectric element 13 inside the case 12.
　次にケース１２の構造を図２Ａ～図２Ｄ、図３を用いて説明する。図２Ａは、実施の形態における超音波デバイス１１のケース１２の上面図である。図２Ｂは、実施の形態における超音波デバイス１１のケース１２の側面図である。図２Ｃは、実施の形態における超音波デバイス１１のケース１２の正面図である。図２Ｄは、実施の形態における超音波デバイス１１のケース１２の斜視図である。図３は、実施の形態における超音波デバイス１１のケース１２の横断面図である。図３は、ケース１２を内底面１９に平行な面で切断したときのケース１２の筒部１７の断面図にほぼ一致する。図２Ａ、図３に示すように、ケース１２は中心点２３を有する。また、図１Ａ、図２Ａ～図２Ｄ、図３に示すように、超音波デバイス１１において、Ｘ方向とＹ方向とＺ方向とが規定される。 Next, the structure of the case 12 will be described with reference to FIGS. 2A to 2D and FIG. FIG. 2A is a top view of the case 12 of the ultrasonic device 11 according to the embodiment. FIG. 2B is a side view of the case 12 of the ultrasonic device 11 according to the embodiment. FIG. 2C is a front view of the case 12 of the ultrasonic device 11 according to the embodiment. FIG. 2D is a perspective view of the case 12 of the ultrasonic device 11 according to the embodiment. FIG. 3 is a cross-sectional view of the case 12 of the ultrasonic device 11 according to the embodiment. FIG. 3 substantially corresponds to a cross-sectional view of the cylindrical portion 17 of the case 12 when the case 12 is cut along a plane parallel to the inner bottom surface 19. As shown in FIGS. 2A and 3, the case 12 has a center point 23. Further, as shown in FIGS. 1A, 2A to 2D, and FIG. 3, in the ultrasonic device 11, the X direction, the Y direction, and the Z direction are defined.
　図２Ａにおいて、ケース１２の内底面１９に対する圧電素子１３が配置される箇所を矩形の破線で示す。ケース１２の内底面１９の中央と圧電素子１３の中央がほぼ一致するように、圧電素子１３が配置される。圧電素子１３のＸ方向の長さは約６ｍｍであり、Ｙ方向の長さは約８ｍｍである。 2A, a portion where the piezoelectric element 13 is disposed with respect to the inner bottom surface 19 of the case 12 is indicated by a rectangular broken line. The piezoelectric element 13 is arranged so that the center of the inner bottom surface 19 of the case 12 and the center of the piezoelectric element 13 are substantially coincident. The length of the piezoelectric element 13 in the X direction is about 6 mm, and the length in the Y direction is about 8 mm.
　図３に示すように、ケース１２の寸法を、筒部１７の外径Ａ、薄壁部２１の開口長Ｂ、厚壁部２２の最小開口長Ｃ、薄壁部２１の壁厚Ｄ、厚壁部２２の最大壁厚Ｅ、厚壁部２２の最大開口長Ｆ、厚壁部２２の幅Ｇ、中心点２３に対する薄壁部２１の中心角α、中心点２３に対する厚壁部２２の中心角β、厚壁部２２の突出部２４の先端半角θで示す。厚壁部２２の突出部２４は、先端２５からケース１２の外周に向かって広がる扇形状を有している。厚壁部２２の突出部２４の先端半角θは、厚壁部２２の突出部２４の先端２５における先端角の１／２である。 As shown in FIG. 3, the dimensions of the case 12 include the outer diameter A of the cylindrical portion 17, the opening length B of the thin wall portion 21, the minimum opening length C of the thick wall portion 22, the wall thickness D of the thin wall portion 21, and the thickness. The maximum wall thickness E of the wall portion 22, the maximum opening length F of the thick wall portion 22, the width G of the thick wall portion 22, the central angle α of the thin wall portion 21 with respect to the center point 23, and the center of the thick wall portion 22 with respect to the center point 23. An angle β and a tip half angle θ of the protrusion 24 of the thick wall portion 22 are shown. The protruding portion 24 of the thick wall portion 22 has a fan shape that extends from the tip 25 toward the outer periphery of the case 12. The leading end half angle θ of the protruding portion 24 of the thick wall portion 22 is ½ of the leading end angle at the leading end 25 of the protruding portion 24 of the thick wall portion 22.
　ここで、薄壁部２１の開口長Ｂとは、薄壁部２１が向かい合う方向（Ｙ方向）の開口長である。厚壁部２２の最小開口長Ｃとは、厚壁部２２が向かい合う方向（Ｘ方向）の最小開口長である。厚壁部２２の最大開口長Ｆとは、厚壁部２２が向かい合う方向（Ｘ方向）の最大開口長である。厚壁部２２の最大壁厚Ｅとは、中心点２３に向かう半径方向の厚壁部２２の最大壁厚である。厚壁部２２の幅Ｇとは、半径方向と垂直な方向の厚壁部２２の幅である。 Here, the opening length B of the thin wall portion 21 is the opening length in the direction in which the thin wall portion 21 faces (Y direction). The minimum opening length C of the thick wall portion 22 is the minimum opening length in the direction (X direction) in which the thick wall portion 22 faces. The maximum opening length F of the thick wall portion 22 is the maximum opening length in the direction (X direction) in which the thick wall portion 22 faces. The maximum wall thickness E of the thick wall portion 22 is the maximum wall thickness of the thick wall portion 22 in the radial direction toward the center point 23. The width G of the thick wall portion 22 is the width of the thick wall portion 22 in the direction perpendicular to the radial direction.
　図４Ａは、本実施の形態の超音波センサ２６のブロック図である。図４Ｂは、本実施の形態の他の超音波センサ２６のブロック図である。超音波センサ２６は、超音波デバイス１１と、送波回路７１と、ハウジングケース７３とを備えている。超音波デバイス１１は、超音波変換器として用いられる。送波回路７１は、超音波デバイス１１を駆動し、超音波を発生させる。ハウジングケース７３は、超音波デバイス１１と送波回路７１とを保持する。ここで、図４Ｂに示すように、ハウジングケース７３は、超音波デバイス１１だけを保持していてもよい。すなわち、ハウジングケース７３は、少なくとも超音波デバイス１１を保持する構成であればよい。 FIG. 4A is a block diagram of the ultrasonic sensor 26 of the present embodiment. FIG. 4B is a block diagram of another ultrasonic sensor 26 of the present embodiment. The ultrasonic sensor 26 includes the ultrasonic device 11, a wave transmission circuit 71, and a housing case 73. The ultrasonic device 11 is used as an ultrasonic transducer. The transmission circuit 71 drives the ultrasonic device 11 to generate ultrasonic waves. The housing case 73 holds the ultrasonic device 11 and the transmission circuit 71. Here, as shown in FIG. 4B, the housing case 73 may hold only the ultrasonic device 11. That is, the housing case 73 only needs to hold at least the ultrasonic device 11.
　図４Ｃは、本実施の形態の超音波センサ２６を取り付けた車両２７の模式図である。超音波センサ２６は、超音波を発信し、反射された超音波を受信することにより、車両２７の周囲の障害物等の存在を検知したり、障害物までの距離を検出したりする。図１Ａでは、超音波デバイス１１のＸ方向とＹ方向を水平に、Ｚ方向を垂直にして表示している。しかし、車両２７に装備する際には、超音波デバイス１１のＸ方向とＺ方向が地面に対して略水平になり、Ｙ方向が略垂直になるように設置される。ここで、超音波を発信または受信する方向がＺ方向である。このように超音波デバイス１１の方向を設定し、超音波デバイス１１の形状を規定することにより、垂直方向の狭指向性を確保しつつ、水平方向の指向性をある程度狭められる。なお、Ｚ方向は車両２７の水平方向に対して若干の角度を設ける場合がある。また、Ｙ方向も垂直方向に対して若干の角度を設ける場合がある。さらに、超音波を発信または受信する方向を水平からわずかに上方または下方に傾ける場合もある。ここで、超音波デバイス１１の指向性とは、超音波デバイス１１が超音波の受信に用いられるときには超音波の受信感度の指向性であり、超音波デバイス１１が超音波の発信に用いられるときには超音波の放射強度の指向性である。 FIG. 4C is a schematic diagram of a vehicle 27 to which the ultrasonic sensor 26 of the present embodiment is attached. The ultrasonic sensor 26 detects the presence of an obstacle around the vehicle 27 and detects the distance to the obstacle by transmitting an ultrasonic wave and receiving the reflected ultrasonic wave. In FIG. 1A, the ultrasonic device 11 is displayed with the X direction and Y direction being horizontal and the Z direction being vertical. However, when the vehicle 27 is equipped, the ultrasonic device 11 is installed so that the X direction and the Z direction are substantially horizontal with respect to the ground and the Y direction is substantially vertical. Here, the direction in which ultrasonic waves are transmitted or received is the Z direction. By setting the direction of the ultrasonic device 11 and defining the shape of the ultrasonic device 11 in this way, the directivity in the horizontal direction can be narrowed to some extent while ensuring the narrow directivity in the vertical direction. Note that the Z direction may have a slight angle with respect to the horizontal direction of the vehicle 27. In addition, the Y direction may have a slight angle with respect to the vertical direction. Furthermore, the direction in which the ultrasonic waves are transmitted or received may be slightly tilted upward or downward from the horizontal. Here, the directivity of the ultrasonic device 11 is the directivity of ultrasonic reception sensitivity when the ultrasonic device 11 is used for reception of ultrasonic waves, and when the ultrasonic device 11 is used for transmission of ultrasonic waves. Directivity of radiation intensity of ultrasonic waves.
　（表１）に本実施の形態において検討した実施例１～６１について、ケース１２の寸法と、指向性の特性値とその評価結果を示す。 (Table 1) shows the dimensions of the case 12, the characteristic values of directivity, and the evaluation results for Examples 1 to 61 studied in this embodiment.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-I000001
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-I000001
　（表１）に示す実施例１～６１において、筒部１７の外径Ａは１４ｍｍまたは１６ｍｍである。薄壁部２１の開口長Ｂは１３ｍｍまたは１５ｍｍである。薄壁部２１の壁厚Ｄは０．５ｍｍである。厚壁部２２の最小開口長Ｃは、６．５ｍｍ以上、１１ｍｍ以下の範囲内であり、厚壁部２２の最大壁厚Ｅは２．０ｍｍ以上、４．５ｍｍ以下の範囲内である。厚壁部２２の突出部２４の先端半角θは、３０度以上、８０度以下の範囲内である。中心点２３に対する薄壁部２１の中心角αは、７４．８度以上、１７０．６度以下の範囲内であり、中心点２３に対する厚壁部２２の中心角βは、９．４度以上、１０５．２度以下の範囲内である。 In Examples 1 to 61 shown in (Table 1), the outer diameter A of the cylindrical portion 17 is 14 mm or 16 mm. The opening length B of the thin wall portion 21 is 13 mm or 15 mm. The wall thickness D of the thin wall portion 21 is 0.5 mm. The minimum opening length C of the thick wall portion 22 is in the range of 6.5 mm to 11 mm, and the maximum wall thickness E of the thick wall portion 22 is in the range of 2.0 mm to 4.5 mm. The tip half angle θ of the protruding portion 24 of the thick wall portion 22 is in the range of 30 degrees or more and 80 degrees or less. The center angle α of the thin wall portion 21 with respect to the center point 23 is in the range of 74.8 degrees or more and 170.6 degrees or less, and the center angle β of the thick wall portion 22 with respect to the center point 23 is 9.4 degrees or more. , 105.2 degrees or less.
　（表１）には、ケース１２の寸法と、超音波放射を行なった際の、最大出力に対する半値（－６ｄＢ）における、垂直方向の指向角と水平方向の指向角とを示している。そして、指向特性が良好な実施例を「Ｇ（Ｇｏｏｄ）」とし、指向特性が良好でない実施例を「ＮＧ（Ｎｏ　Ｇｏｏｄ）」としている。 (Table 1) shows the dimensions of the case 12 and the vertical and horizontal directivity angles at half-value (−6 dB) with respect to the maximum output when ultrasonic radiation is performed. An example in which directivity characteristics are good is “G (Good)”, and an example in which directivity characteristics are not good is “NG (No Good)”.
　ここで、外径Ａが１４．０ｍｍの場合、垂直方向の指向角が４６度以下で、かつ、水平方向の指向角が７０度以下の場合を良好としている。指向角は、最大出力に対する半値である－６ｄＢの場合の値である。すなわち、（表１）に示すように、外径Ａが１４．０ｍｍの場合、指向角特性が良好なのは実施例７、８、１５、１６、１７、２２、２３、２４、２５、２９、３０、３１である。 Here, when the outer diameter A is 14.0 mm, the vertical direction angle is 46 degrees or less and the horizontal direction angle is 70 degrees or less. The directivity angle is a value in the case of −6 dB which is a half value with respect to the maximum output. That is, as shown in (Table 1), when the outer diameter A is 14.0 mm, the directivity angle characteristics are good in Examples 7, 8, 15, 16, 17, 22, 23, 24, 25, 29, 30. , 31.
　また、外径Ａが１６．０ｍｍの場合、垂直方向の指向角が３７度以下で、かつ、水平方向の指向角が６７度以下の場合を良好としている。指向角は、最大出力に対する半値である－６ｄＢの場合の値である。すなわち、（表１）に示すように、外径Ａが１６．０ｍｍの場合、指向角特性が良好なのは実施例３４、３５、４１、４２、４８、５４、５５である。 Also, when the outer diameter A is 16.0 mm, the vertical direction angle is 37 degrees or less and the horizontal direction angle is 67 degrees or less. The directivity angle is a value in the case of −6 dB which is a half value with respect to the maximum output. That is, as shown in (Table 1), when the outer diameter A is 16.0 mm, Examples 34, 35, 41, 42, 48, 54, and 55 have good directivity characteristics.
　図５～図１４は、実施の形態における超音波デバイス１１の指向角特性を示す図である。図５～図１４において、横軸は突出部２４の先端半角θであり、縦軸は最大出力に対する半値である－６ｄＢの場合の指向角を示している。なお、図５から図１４の各特性図において、突出部２４の先端半角θが９０度の場合も示している。これは、突出部２４が存在しない従来の超音波デバイス１の特性を、比較例として示したものである。図５から図１４の特性図において、指向角特性の良好な範囲を矢印で示している。 5 to 14 are diagrams showing directivity characteristics of the ultrasonic device 11 according to the embodiment. 5 to 14, the horizontal axis represents the tip half angle θ of the protrusion 24, and the vertical axis represents the directivity angle in the case of −6 dB which is a half value with respect to the maximum output. 5 to 14 also show the case where the tip half angle θ of the protrusion 24 is 90 degrees. This shows, as a comparative example, the characteristics of the conventional ultrasonic device 1 in which the protruding portion 24 does not exist. In the characteristic diagrams of FIGS. 5 to 14, an excellent range of the directivity angle characteristic is indicated by an arrow.
　図５は、外径Ａが１４ｍｍ、最小開口長Ｃが６．５ｍｍの場合を示している。図６は、外径Ａが１４ｍｍ、最小開口長Ｃが７．０ｍｍの場合を示している。図７は、外径Ａが１４ｍｍ、最小開口長Ｃが８．０ｍｍの場合を示している。図８は、外径Ａが１４ｍｍ、最小開口長Ｃが９．０ｍｍの場合を示している。図９は、外径Ａが１４ｍｍ、最小開口長Ｃが１０．０ｍｍの場合を示している。 FIG. 5 shows a case where the outer diameter A is 14 mm and the minimum opening length C is 6.5 mm. FIG. 6 shows a case where the outer diameter A is 14 mm and the minimum opening length C is 7.0 mm. FIG. 7 shows a case where the outer diameter A is 14 mm and the minimum opening length C is 8.0 mm. FIG. 8 shows a case where the outer diameter A is 14 mm and the minimum opening length C is 9.0 mm. FIG. 9 shows a case where the outer diameter A is 14 mm and the minimum opening length C is 10.0 mm.
　図１０は、外径Ａが１６ｍｍ、最小開口長Ｃが７．０ｍｍの場合を示している。図１１は、外径Ａが１６ｍｍ、最小開口長Ｃが８．０ｍｍの場合を示している。図１２は、外径Ａが１６ｍｍ、最小開口長Ｃが９．０ｍｍの場合を示している。図１３は、外径Ａが１６ｍｍ、最小開口長Ｃが１０．０ｍｍの場合を示している。図１４は、外径Ａが１６ｍｍ、最小開口長Ｃが１１．０ｍｍの場合を示している。 FIG. 10 shows a case where the outer diameter A is 16 mm and the minimum opening length C is 7.0 mm. FIG. 11 shows a case where the outer diameter A is 16 mm and the minimum opening length C is 8.0 mm. FIG. 12 shows a case where the outer diameter A is 16 mm and the minimum opening length C is 9.0 mm. FIG. 13 shows a case where the outer diameter A is 16 mm and the minimum opening length C is 10.0 mm. FIG. 14 shows a case where the outer diameter A is 16 mm and the minimum opening length C is 11.0 mm.
　図５において、指向角特性の良好な範囲は存在しない。図６において、指向角特性の良好な範囲は、突出部２４の先端半角θが、２５度から３８度の範囲である。図７において、指向角特性の良好な範囲は、突出部２４の先端半角θが、３５度から６５度の範囲である。図８において、指向角特性の良好な範囲は、突出部２４の先端半角θが、４５度から８５度の範囲である。図９において、指向角特性の良好な範囲は、突出部２４の先端半角θが、５５度から８５度の範囲である。図１０において、指向角特性の良好な範囲は、突出部２４の先端半角θが、４５度から６５度の範囲である。図１１において、指向角特性の良好な範囲は、突出部２４の先端半角θが、５５度から７５度の範囲である。図１２において、指向角特性の良好な範囲は、突出部２４の先端半角θが、６５度から７５度の範囲である。図１３において、指向角特性の良好な範囲は、突出部２４の先端半角θが、６５度から８５度の範囲である。図１４において、指向角特性の良好な範囲は存在しない。 In FIG. 5, there is no good range of directivity characteristics. In FIG. 6, a good range of the directivity angle characteristic is a range where the tip half angle θ of the protrusion 24 is from 25 degrees to 38 degrees. In FIG. 7, a favorable range of the directivity angle characteristic is a range where the tip half angle θ of the protrusion 24 is from 35 degrees to 65 degrees. In FIG. 8, a good range of the directivity angle characteristic is a range in which the tip half angle θ of the protrusion 24 is from 45 degrees to 85 degrees. In FIG. 9, a good range of the directivity angle characteristic is a range in which the tip half angle θ of the protrusion 24 is from 55 degrees to 85 degrees. In FIG. 10, a favorable range of the directivity angle characteristic is a range where the tip half angle θ of the protrusion 24 is 45 degrees to 65 degrees. In FIG. 11, a favorable range of the directivity angle characteristic is a range where the tip half angle θ of the protrusion 24 is 55 degrees to 75 degrees. In FIG. 12, a favorable range of the directivity angle characteristic is a range where the tip half angle θ of the protrusion 24 is from 65 degrees to 75 degrees. In FIG. 13, a good range of the directivity angle characteristic is a range in which the tip half angle θ of the protrusion 24 is from 65 degrees to 85 degrees. In FIG. 14, there is no good range of directivity angle characteristics.
　本実施の形態の超音波デバイス１１は、有底筒状のケース１２の内底面１９に圧電素子１３を有している。そして、ケース１２の筒部１７は、ケース１２の内底面１９に平行な断面において、内底面１９がケース１２の中心点２３を中心とする略円弧状の薄壁部２１と、薄壁部２１よりも壁厚が厚く内壁面がケース１２の内部空間に向かって突出した突出部２４を設けた厚壁部２２とを有している。この構成により、超音波デバイス１１は、従来の指向性のレベルを超えた指向性の設計が可能になり、Ｙ方向の狭指向性を十分に確保しつつ、Ｘ方向の指向性を狭めることが可能になる。超音波デバイス１１を、超音波変換器として備えた超音波センサ２６を車両２７に装備して障害物の検出用に使用することにより、路面からの反射や、車庫などの天井からの反射による影響を低減するとともに、水平方向にも指向性の絞れた検出が可能になる。すなわち、駐車場等において、車両２７の駐車幅程度の空きスペースを検出できる。 The ultrasonic device 11 of the present embodiment has the piezoelectric element 13 on the inner bottom surface 19 of the bottomed cylindrical case 12. The cylindrical portion 17 of the case 12 has a substantially arc-shaped thin wall portion 21 with the inner bottom surface 19 centering on the center point 23 of the case 12 and a thin wall portion 21 in a cross section parallel to the inner bottom surface 19 of the case 12. And a thick wall portion 22 provided with a protruding portion 24 whose inner wall surface protrudes toward the internal space of the case 12. With this configuration, the ultrasonic device 11 can be designed with directivity exceeding the level of conventional directivity, and can narrow the directivity in the X direction while sufficiently securing the narrow directivity in the Y direction. It becomes possible. By installing an ultrasonic sensor 26 equipped with the ultrasonic device 11 as an ultrasonic transducer on a vehicle 27 and using it for detecting an obstacle, the influence of reflection from a road surface or reflection from a ceiling of a garage or the like. In addition, the detection with reduced directivity in the horizontal direction is possible. That is, it is possible to detect an empty space that is about the parking width of the vehicle 27 in a parking lot or the like.
　また、本実施の形態の超音波デバイス１１は、有底筒状のケース１２の内底面１９に圧電素子１３を有している。そして、ケース１２の筒部１７はケース１２の内底面１９に平行な断面において、壁厚が略一定の薄壁部２１と、薄壁部２１よりも壁厚が厚く内側面がケース１２の内側空間に向かって突出した突出部２４を設けた厚壁部２２とを有している。この構成により、指向性のレベルが向上し、Ｙ方向の狭指向性を十分に確保しつつ、Ｘ方向の指向性を狭めることが可能になる。超音波デバイス１１を、超音波変換器として備えた超音波センサ２６を車両２７に装備して障害物の検出用に使用することにより、路面からの反射や、車庫などの天井からの反射による影響を低減するとともに、水平方向にも指向性の絞れた検出が可能になる。すなわち、駐車場等において、車両２７の駐車幅程度の空きスペースを検出できる。 Further, the ultrasonic device 11 of the present embodiment has the piezoelectric element 13 on the inner bottom surface 19 of the bottomed cylindrical case 12. The cylindrical portion 17 of the case 12 has a thin wall portion 21 having a substantially constant wall thickness in a cross section parallel to the inner bottom surface 19 of the case 12, and an inner side surface that is thicker than the thin wall portion 21 and is inside the case 12. And a thick wall portion 22 provided with a protruding portion 24 protruding toward the space. With this configuration, the directivity level is improved, and the directivity in the X direction can be narrowed while sufficiently ensuring the narrow directivity in the Y direction. By installing an ultrasonic sensor 26 equipped with the ultrasonic device 11 as an ultrasonic transducer on a vehicle 27 and using it for detecting an obstacle, the influence of reflection from a road surface or reflection from a ceiling of a garage or the like. In addition, the detection with reduced directivity in the horizontal direction is possible. That is, it is possible to detect an empty space that is about the parking width of the vehicle 27 in a parking lot or the like.
　さらに、ケース１２の内底面１９に平行な断面において、ケース１２は、対向する一対の薄壁部２１と、対向する一対の厚壁部２２とを有することが好ましい。すなわち、ケース１２の内底面に平行な断面において、第１の薄壁部２１Ａと第２の薄壁部２１Ｂとは互いに対向しており、第１の厚壁部２２Ａと第２の厚壁部２２Ｂとは互いに対向している。また、第１の厚壁部２２Ａは、ケース１２の内底面の中心点２３に対して、第２の厚壁部２２Ｂと対称に形成されている。 Furthermore, in a cross section parallel to the inner bottom surface 19 of the case 12, the case 12 preferably has a pair of opposed thin wall portions 21 and a pair of opposed thick wall portions 22. That is, in the cross section parallel to the inner bottom surface of the case 12, the first thin wall portion 21A and the second thin wall portion 21B are opposed to each other, and the first thick wall portion 22A and the second thick wall portion. 22B is opposed to each other. Further, the first thick wall portion 22 </ b> A is formed symmetrically with the second thick wall portion 22 </ b> B with respect to the center point 23 of the inner bottom surface of the case 12.
　この構成により、超音波デバイス１１は、Ｘ方向の指向性とＹ方向の指向性をより十分に制御でき、Ｙ方向の狭指向性を十分に確保しつつ、Ｘ方向の指向性を狭めることが可能になる。 With this configuration, the ultrasonic device 11 can more sufficiently control the directivity in the X direction and the directivity in the Y direction, and can narrow the directivity in the X direction while sufficiently securing the narrow directivity in the Y direction. It becomes possible.
　さらに、ケース１２の中心点２３に対する薄壁部２１の中心角α（第１の中心角）はケース１２の中心点２３に対する厚壁部２２の中心角β（第２の中心角）よりも大きいことが好ましい。すなわち、ケース１２の内底面に平行な断面において、第１の薄壁部２１Ａが形成されたケース１２の内壁面（第１の薄壁部２１Ａの外壁面）を第１の円弧５１とし、第１の厚壁部２２Ａが形成されたケース１２の内壁面（第１の厚壁部２２Ａの外壁面）を第２の円弧５２とした場合、第１の円弧５１のケース１２の中心点２３に対する第１の中心角αは、第２の円弧５２のケース１２の中心点２３に対する第２の中心角βよりも大きいことが好ましい。言い換えれば、第１の円弧５１は、第２の円弧５２よりも長いことが好ましい。 Furthermore, the central angle α (first central angle) of the thin wall portion 21 with respect to the central point 23 of the case 12 is larger than the central angle β (second central angle) of the thick wall portion 22 with respect to the central point 23 of the case 12. It is preferable. That is, in the cross section parallel to the inner bottom surface of the case 12, the inner wall surface (the outer wall surface of the first thin wall portion 21A) of the case 12 in which the first thin wall portion 21A is formed is defined as the first arc 51. When the inner wall surface (the outer wall surface of the first thick wall portion 22A) of the case 12 in which the first thick wall portion 22A is formed is the second arc 52, the first arc 51 with respect to the center point 23 of the case 12 The first center angle α is preferably larger than the second center angle β of the second arc 52 with respect to the center point 23 of the case 12. In other words, the first arc 51 is preferably longer than the second arc 52.
　この構成により、超音波デバイス１１は、Ｙ方向の狭指向性を十分に確保しつつ、Ｘ方向の指向性を効果的に狭めることができる。超音波デバイス１１を、超音波変換器として備えた超音波センサ２６を車両２７に装備して障害物の検出用に使用することにより、路面からの反射や、車庫などの天井からの反射による影響を低減するとともに、水平方向にも優れた狭指向性を実現できる。すなわち、駐車場等において、高い精度で車両２７の駐車幅程度の空きスペースを検出できる。 With this configuration, the ultrasonic device 11 can effectively narrow the directivity in the X direction while sufficiently securing the narrow directivity in the Y direction. By installing an ultrasonic sensor 26 equipped with the ultrasonic device 11 as an ultrasonic transducer on a vehicle 27 and using it for detecting an obstacle, the influence of reflection from a road surface or reflection from a ceiling of a garage or the like. In addition, it is possible to achieve excellent narrow directivity in the horizontal direction. That is, it is possible to detect an empty space about the parking width of the vehicle 27 with high accuracy in a parking lot or the like.
　さらに、ケース１２の内底面１９に平行な断面において、厚壁部２２は、突出部２４の先端２５からケース１２の外周に向かって広がる扇形状を有することが好ましい。すなわち、第１の厚壁部２２Ａは、第１の突出部２４Ａの先端２５Ａと第２の円弧５２の両端を結ぶ２本の線分と、第２の円弧５２と、で形成される扇形状であるのが好ましい。この構成により、超音波デバイス１１は、Ｘ方向とＹ方向の指向性の制御を良好に行なえる。 Furthermore, in the cross section parallel to the inner bottom surface 19 of the case 12, the thick wall portion 22 preferably has a fan shape that extends from the tip 25 of the protruding portion 24 toward the outer periphery of the case 12. That is, the first thick wall portion 22A has a fan shape formed by two line segments connecting the tip 25A of the first protruding portion 24A and both ends of the second arc 52, and the second arc 52. Is preferred. With this configuration, the ultrasonic device 11 can satisfactorily control the directivity in the X direction and the Y direction.
　さらに、ケース１２の内底面１９に平行な断面において、ケース１２の中心点２３に対する薄壁部２１の中心角αを、１００度以上、１５５度以下とすることが好ましい。すなわち、第１の円弧５１のケース１２の中心点２３に対する第１の中心角αは、１００度以上、１５５度以下であるのが好ましい。この構成により、超音波デバイス１１は、垂直方向の狭指向性を十分に確保しつつ、水平方向の指向性を効果的に狭められる。 Further, in the cross section parallel to the inner bottom surface 19 of the case 12, the central angle α of the thin wall portion 21 with respect to the center point 23 of the case 12 is preferably set to 100 degrees or more and 155 degrees or less. That is, the first central angle α of the first arc 51 with respect to the central point 23 of the case 12 is preferably 100 degrees or more and 155 degrees or less. With this configuration, the ultrasonic device 11 can effectively narrow the directivity in the horizontal direction while sufficiently ensuring the narrow directivity in the vertical direction.
　さらに、対向する厚壁部２２の突出部２４の先端２５同士を結ぶ開口長（すなわち、厚壁部２２の最小開口長Ｃ）は、ケース１２の外径Ａ（筒部１７の外径Ａ）の０．３５倍以上、０．８倍以下であるのが好ましい。さらに、薄壁部２１の厚みＤはケース１２の外径Ａの０．０２倍以上、０．０６倍以下であることが好ましい。すなわち、ケース１２の内底面に平行な断面において、第１の厚壁部２２Ａの第１の突出部２４Ａの先端２５Ａ（第１の先端）と、第２の厚壁部２２Ｂの第２の突出部２４Ｂの先端２５Ｂ（第２の先端）との間の距離は、ケース１２の外径Ａの０．３５倍以上、０．８倍以下であるのが好ましい。さらに、第１の薄壁部２１Ａの厚みはケース１２の外径Ａの０．０２倍以上、０．０６倍以下であるのが好ましい。この構成により、超音波デバイス１１は、垂直方向の狭指向性を十分に確保しつつ、水平方向の指向性を効果的に狭めることができる。 Furthermore, the opening length connecting the tips 25 of the protruding portions 24 of the opposing thick wall portions 22 (that is, the minimum opening length C of the thick wall portions 22) is the outer diameter A of the case 12 (the outer diameter A of the cylindrical portion 17). It is preferably 0.35 times or more and 0.8 times or less. Further, the thickness D of the thin wall portion 21 is preferably 0.02 times or more and 0.06 times or less of the outer diameter A of the case 12. That is, in the cross section parallel to the inner bottom surface of the case 12, the tip 25A (first tip) of the first protrusion 24A of the first thick wall portion 22A and the second protrusion of the second thick wall portion 22B. The distance between the tip 24B (second tip) of the portion 24B is preferably 0.35 times or more and 0.8 times or less of the outer diameter A of the case 12. Furthermore, the thickness of the first thin wall portion 21A is preferably 0.02 times or more and 0.06 times or less the outer diameter A of the case 12. With this configuration, the ultrasonic device 11 can effectively narrow the directivity in the horizontal direction while sufficiently ensuring the narrow directivity in the vertical direction.
　さらに、超音波デバイス１１は、薄壁部２１を上下方向に配置し、厚壁部２２を左右に配置することが好ましい。言い換えれば、ケース１２の底部が対象物に向かうように設置され、第１の厚壁部２２Ａの第１の突出部２４Ａの先端２５Ａと、第２の厚壁部２２Ｂの第２の突出部２４Ｂの先端２５Ｂとを結んだ線分が、水平方向に対応するように配置されるのが好ましい。この構成により、超音波デバイス１１は、垂直方向の狭指向性を十分に確保しつつ、水平方向の指向性を効果的に狭めることができる。なお、ここでいう上下方向は、垂直方向に対して±５度の範囲を有し、ここでいう左右方向は水平方向に対して±５度の範囲を有し得る。 Furthermore, in the ultrasonic device 11, it is preferable to arrange the thin wall portion 21 in the vertical direction and the thick wall portion 22 to the left and right. In other words, the bottom of the case 12 is installed so as to face the object, the tip 25A of the first protrusion 24A of the first thick wall 22A, and the second protrusion 24B of the second thick wall 22B. It is preferable that the line segment connecting the distal end 25B of the lens is arranged so as to correspond to the horizontal direction. With this configuration, the ultrasonic device 11 can effectively narrow the directivity in the horizontal direction while sufficiently ensuring the narrow directivity in the vertical direction. The vertical direction here may have a range of ± 5 degrees with respect to the vertical direction, and the horizontal direction herein may have a range of ± 5 degrees with respect to the horizontal direction.
　なお、本実施の形態では、薄壁部２１の厚みを略一定としたが、略一定でなくても可能である。例えば、薄壁部２１の厚みに傾斜を持たせてもよい。 In the present embodiment, the thickness of the thin wall portion 21 is substantially constant. However, the thickness is not necessarily constant. For example, the thickness of the thin wall portion 21 may be inclined.
　上記構成により、本開示の超音波デバイスおよび超音波センサは、垂直方向の狭指向性を確保しつつ、水平方向にも指向性を狭めることができる。 With the above configuration, the ultrasonic device and the ultrasonic sensor of the present disclosure can narrow the directivity in the horizontal direction while ensuring the narrow directivity in the vertical direction.
　本開示に係る超音波デバイスおよび超音波センサは、例えば車両などの近くに存在する物体を検出するための検出器として有用である。 The ultrasonic device and the ultrasonic sensor according to the present disclosure are useful as a detector for detecting an object existing near a vehicle, for example.
　１　超音波デバイス
　２　ケース
　３　圧電素子
　４　充填材
　５　リード線
　１１　超音波デバイス
　１２　ケース
　１３　圧電素子
　１４　リード線
　１５　充填材
　１６　底部
　１７　筒部
　１９　内底面
　２０　外底面
　２１　薄壁部
　２１Ａ　第１の薄壁部
　２１Ｂ　第２の薄壁部
　２２　厚壁部
　２２Ａ　第１の厚壁部
　２２Ｂ　第２の厚壁部
　２３　中心点
　２４　突出部
　２４Ａ　第１の突出部
　２４Ｂ　第２の突出部
　２５，２５Ａ，２５Ｂ　先端
　２６　超音波センサ
　２７　車両
　５１　第１の円弧
　５２　第２の円弧
　７１　送波回路
　７３　ハウジングケース
　Ａ，Ｍ　外径
　Ｂ　開口長
　Ｃ　最小開口長
　Ｄ　壁厚
　Ｅ　最大壁厚
　Ｆ　最大開口長
　Ｇ　幅 DESCRIPTION OF SYMBOLS 1 Ultrasonic device 2 Case 3 Piezoelectric element 4 Filler 5 Lead wire 11 Ultrasonic device 12 Case 13 Piezoelectric element 14 Lead wire 15 Filler 16 Bottom part 17 Cylinder part 19 Inner bottom face 20 Outer bottom face 21 Thin wall part 21A 1st thin part Wall portion 21B Second thin wall portion 22 Thick wall portion 22A First thick wall portion 22B Second thick wall portion 23 Center point 24 Projection portion 24A First projection portion 24B Second projection portion 25, 25A, 25B Tip 26 Ultrasonic sensor 27 Vehicle 51 First arc 52 Second arc 71 Transmission circuit 73 Housing case A, M Outer diameter B Opening length C Minimum opening length D Wall thickness E Maximum wall thickness F Maximum opening length G Width

Claims (12)

  1. 有底筒状のケースと、
    前記ケースの内底面に設置された圧電素子と、
    前記圧電素子に接続されたリード線と、
    前記ケースを封止する充填材と、
    を備え、
    前記ケースは、
    前記ケースの内壁面に沿って形成された第１の薄壁部と、
    前記ケースの内壁面から前記ケースの内部空間に向かって突出した第１の突出部を有する第１の厚壁部と、
    を有する
    超音波デバイス。     A bottomed cylindrical case,
    A piezoelectric element installed on the inner bottom surface of the case;
    A lead wire connected to the piezoelectric element;
    A filler for sealing the case;
    With
    The case is
    A first thin wall formed along the inner wall surface of the case;
    A first thick wall portion having a first protrusion protruding from the inner wall surface of the case toward the inner space of the case;
    Ultrasonic device having
  2. 前記第１の薄壁部の厚さは、略一定である
    請求項１に記載の超音波デバイス。     The ultrasonic device according to claim 1, wherein a thickness of the first thin wall portion is substantially constant.
  3. 前記第１の薄壁部の厚さは、前記第１の薄壁部の平均の厚さに対して、±１０％以下である
    請求項２に記載の超音波デバイス。     The ultrasonic device according to claim 2, wherein a thickness of the first thin wall portion is ± 10% or less with respect to an average thickness of the first thin wall portion.
  4. 前記ケースは、
    前記ケースの内壁面に沿って形成された第２の薄壁部と、
    前記ケースの内壁面から前記ケースの内部空間に向かって突出した第２の突出部を有する第２の厚壁部と、
    を更に有し、
    前記ケースの前記内底面に平行な断面において、
    前記第１の薄壁部と前記第２の薄壁部とは互いに対向しており、
    前記第１の厚壁部と前記第２の厚壁部とは互いに対向している、
    請求項１に記載の超音波デバイス。     The case is
    A second thin wall portion formed along the inner wall surface of the case;
    A second thick wall portion having a second protrusion protruding from the inner wall surface of the case toward the internal space of the case;
    Further comprising
    In a cross section parallel to the inner bottom surface of the case,
    The first thin wall portion and the second thin wall portion are opposed to each other,
    The first thick wall portion and the second thick wall portion are opposed to each other.
    The ultrasonic device according to claim 1.
  5. 前記ケースの前記内底面に平行な断面において、
    前記第１の薄壁部は、前記ケースの前記内底面の中心点に対して、前記第２の薄壁部と対称に形成されており、
    前記第１の厚壁部は、前記ケースの前記内底面の中心点に対して、前記第２の厚壁部と対称に形成されている
    請求項４に記載の超音波デバイス。     In a cross section parallel to the inner bottom surface of the case,
    The first thin wall portion is formed symmetrically with the second thin wall portion with respect to a center point of the inner bottom surface of the case,
    The ultrasonic device according to claim 4, wherein the first thick wall portion is formed symmetrically with the second thick wall portion with respect to a center point of the inner bottom surface of the case.
  6. 前記ケースの前記内底面に平行な断面において、
    前記第１の薄壁部が形成された前記ケースの前記内壁面を第１の円弧とし、
    前記第１の厚壁部が形成された前記ケースの前記内壁面を第２の円弧とした場合、
    前記第１の円弧の前記ケースの前記中心点に対する第１の中心角は、
    前記第２の円弧の前記ケースの前記中心点に対する第２の中心角よりも大きい
    請求項５に記載の超音波デバイス。     In a cross section parallel to the inner bottom surface of the case,
    The inner wall surface of the case in which the first thin wall portion is formed is a first arc,
    When the inner wall surface of the case in which the first thick wall portion is formed is a second arc,
    The first central angle of the first arc with respect to the central point of the case is:
    The ultrasonic device according to claim 5, wherein the second arc is larger than a second center angle with respect to the center point of the case.
  7. 前記ケースの前記内底面に平行な断面において、
    前記第１の薄壁部が形成された前記ケースの前記内壁面を第１の円弧とし、
    前記第１の厚壁部が形成された前記ケースの前記内壁面を第２の円弧とした場合、
    前記第１の円弧は、前記第２の円弧よりも長い
    請求項５に記載の超音波デバイス。     In a cross section parallel to the inner bottom surface of the case,
    The inner wall surface of the case in which the first thin wall portion is formed is a first arc,
    When the inner wall surface of the case in which the first thick wall portion is formed is a second arc,
    The ultrasonic device according to claim 5, wherein the first arc is longer than the second arc.
  8. 前記ケースの前記内底面に平行な断面において、
    前記第１の薄壁部が形成された前記ケースの前記内壁面を第１の円弧とし、
    前記第１の厚壁部が形成された前記ケースの前記内壁面を第２の円弧とした場合、
    前記第１の厚壁部は、前記第１の突出部の第１の先端と前記第２の円弧の両端を結ぶ線分と、前記第２の円弧と、で形成される扇形状である
    請求項５に記載の超音波デバイス。     In a cross section parallel to the inner bottom surface of the case,
    The inner wall surface of the case in which the first thin wall portion is formed is a first arc,
    When the inner wall surface of the case in which the first thick wall portion is formed is a second arc,
    The first thick wall portion has a fan shape formed by a line segment connecting a first tip of the first protrusion and both ends of the second arc, and the second arc. Item 6. The ultrasonic device according to Item 5.
  9. 前記ケースの前記内底面に平行な断面において、
    前記第１の薄壁部が形成された前記ケースの前記内壁面を第１の円弧とし、
    前記第１の厚壁部が形成された前記ケースの前記内壁面を第２の円弧とした場合、
    前記第１の円弧の前記ケースの前記中心点に対する第１の中心角は、１００度以上、１５５度以下である
    請求項５に記載の超音波デバイス。     In a cross section parallel to the inner bottom surface of the case,
    The inner wall surface of the case in which the first thin wall portion is formed is a first arc,
    When the inner wall surface of the case in which the first thick wall portion is formed is a second arc,
    The ultrasonic device according to claim 5, wherein a first central angle of the first arc with respect to the central point of the case is 100 degrees or more and 155 degrees or less.
  10. 前記ケースの前記内底面に平行な断面において、
    前記第１の厚壁部の前記第１の突出部の第１の先端と、前記第２の厚壁部の前記第２の突出部の第２の先端との間の距離は、
    前記ケースの外径Ａの０．３５倍以上、０．８倍以下であり、
    前記第１の薄壁部の厚みは前記ケースの外径Ａの０．０２倍以上、０．０６倍以下である
    請求項５記載の超音波デバイス。     In a cross section parallel to the inner bottom surface of the case,
    The distance between the first tip of the first protrusion of the first thick wall portion and the second tip of the second protrusion of the second thick wall portion is:
    0.35 times or more and 0.8 times or less of the outer diameter A of the case,
    The ultrasonic device according to claim 5, wherein a thickness of the first thin wall portion is 0.02 times or more and 0.06 times or less of an outer diameter A of the case.
  11. 前記ケースの底部が対象物に向かうように設置され、
    前記第１の厚壁部の前記第１の突出部の第１の先端と、前記第２の厚壁部の前記第２の突出部の第２の先端とを結んだ線分が、水平方向に対応するように配置される
    請求項５記載の超音波デバイス。     Installed so that the bottom of the case faces the object,
    A line segment connecting the first tip of the first protruding portion of the first thick wall portion and the second tip of the second protruding portion of the second thick wall portion is a horizontal direction. The ultrasonic device according to claim 5, which is arranged so as to correspond to the above.
  12. 請求項１に記載の超音波デバイスと、
    前記超音波デバイスを駆動し、超音波を発生させる送波回路と、
    前記超音波デバイスを保持するハウジングケースと、
    を備えた
    超音波センサ。     An ultrasonic device according to claim 1;
    A transmission circuit for driving the ultrasonic device and generating ultrasonic waves;
    A housing case for holding the ultrasonic device;
    Ultrasonic sensor equipped with.
PCT/JP2016/002321 2015-05-25 2016-05-12 Ultrasonic device and ultrasonic sensor using same WO2016189812A1 (en)

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