JP2009225419A - Ultrasonic sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To accomplish an ultrasonic sensor which oscillates an ultrasonic wave of high sound pressure and is can reduce oscillation noise. <P>SOLUTION: In an ultrasonic sensor 10, a layered piezoelectric element 16, in which a plurality of layers of piezoelectric elements are formed and which oscillates ultrasonic waves, is used for a transmitting device 11, thereby oscillating the ultrasonic wave of high sound pressure. Furthermore, an oscillation separating member 90 is equipped, provided in between the transmitting device 11 and neighboring receiving devices 12p and 12r, erected from a bottom face 31a of a case 31 and fixed in one terminal by an oscillation attenuating member 18 so as to partition the inside of the case 31, while surrounding the transmitting device 11, thereby reducing the oscillation noise generated by transferring the ultrasonic wave from the transmitting device 11 to the receiving devices 12p-12r. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an ultrasonic sensor in which a transmitting element and a receiving element including an acoustic matching member and a piezoelectric element are arranged in an array.

To obtain ultrasonic images used in the medical field and ultrasonic sensors that measure the position and shape of obstacles in front of an ultrasonic sensor as an ultrasonic sensor in which receiving elements and transmitting elements are arranged in an array Ultrasonic transducers are known.
For example, Patent Document 1 discloses an array type ultrasonic transducer in which vibration elements are connected by a fixing material such as a hard resin. Note that an ultrasonic sensor using an acoustic matching layer has a generally well-known structure, and detection in the air with a large attenuation factor is required particularly for in-vehicle use.
Japanese Patent Application Laid-Open No. 2000-253496

  In such an ultrasonic sensor, in order to improve the detection sensitivity of the ultrasonic wave, it is necessary to increase the sound pressure of the ultrasonic wave to be transmitted, but it is necessary to increase the amplitude of the transmitting element. There is a problem that vibration is transmitted to the vibrating element to generate vibration noise.

  Therefore, an object of the present invention is to realize an ultrasonic sensor that can oscillate ultrasonic waves with high sound pressure and reduce vibration noise.

  In order to achieve the above object, according to the first aspect of the present invention, in the ultrasonic sensor, in the ultrasonic sensor, the piezoelectric element is formed by laminating a plurality of layers, and an ultrasonic wave is oscillated. A first acoustic matching member that transmits the oscillated ultrasonic wave, a transmitting element that transmits ultrasonic waves to the detected object, and a piezoelectric element that detects the ultrasonic waves reflected by the detected object And a second acoustic matching member that transmits the ultrasonic wave reflected by the detected body to the piezoelectric element, and a receiving element that receives the ultrasonic wave reflected by the detected body, At least one of each is provided, the transmitting element and the receiving element are arranged in an array, and the transmitting element and the receiving element are accommodated in a box shape having one end opened for placement on a predetermined object. Formed housing and each acoustic matching A vibration attenuating member that is provided between a material and an opening of the housing, fixes the acoustic matching member to the housing, and attenuates vibrations transmitted between the acoustic matching members; A vibration separating member that is provided between the transmitting element and an adjacent receiving element, divides the interior of the casing so as to surround the transmitting element, and reduces transmission of ultrasonic vibration from the transmitting element to the receiving element And using a technical means.

  According to the first aspect of the present invention, since the piezoelectric element is laminated in a plurality of layers and the laminated piezoelectric element that oscillates ultrasonic waves is used as the transmitting element, it is possible to oscillate ultrasonic waves with high sound pressure. it can. Also, provided with a vibration separating member that is provided between the transmitting element and the adjacent receiving element, divides the inside of the housing around the transmitting element, and reduces transmission of ultrasonic vibration from the transmitting element to the receiving element. Therefore, vibration noise generated by transmitting ultrasonic waves from the transmitting element to the receiving element can be reduced. That is, it is possible to realize an ultrasonic sensor that can oscillate a high sound pressure ultrasonic wave and reduce vibration noise.

  According to a second aspect of the present invention, in the ultrasonic sensor according to the first aspect, the transmission element is provided between the piezoelectric element and the laminated piezoelectric element and a bottom surface and an inner side surface of the housing. And a first buffer material that protects the receiving element from a load of external force, and the vibration isolation member is formed of a material having an acoustic impedance higher than that of the first buffer material. .

  According to the second aspect of the present invention, it is possible to protect the transmitting element and the receiving element from an external force load by the first buffer material. In addition, since the vibration separating member is made of a material having an acoustic impedance higher than that of the first buffer material, ultrasonic waves transmitted from the laminated piezoelectric element via the first buffer material are transmitted to the vibration separating member and the first buffer material. It can reflect in the interface with one buffer material. Thereby, even if an ultrasonic wave with a high sound pressure is oscillated from the transmitting element, vibration noise generated by transmitting the ultrasonic wave from the transmitting element to the receiving element can be reduced.

  According to a third aspect of the present invention, in the ultrasonic sensor according to the first or second aspect, the vibration separating member is provided with technical means that at least a part of the vibration separating member is integrally formed. Use.

  According to the invention described in claim 3, at least a part of the vibration separating member can be integrally formed with the housing. According to this, the number of parts can be reduced, and the positional accuracy of the vibration separating member can be improved.

  According to a fourth aspect of the present invention, in the ultrasonic sensor according to any one of the first to third aspects, the vibration separating member is configured such that the acoustic matching member side is thinner than the piezoelectric element side. The technical means that it is formed is used.

  According to the fourth aspect of the present invention, the vibration separating member can be formed so that the acoustic matching member side is thinner than the piezoelectric element side. According to this, it is possible not to inhibit the vibration of the acoustic matching member, and it is possible to increase the strength of the vibration separating member.

  According to a fifth aspect of the present invention, in the ultrasonic sensor according to any one of the first to fourth aspects, the vibration separating member sandwiches the core material with a material having a higher elastic modulus than the core material. The technical means of having a laminated structure formed in (1) is used.

  According to the invention described in claim 5, the vibration separating member can be formed to have a laminated structure formed by sandwiching the core material with a material having a higher elastic modulus than the core material. According to this, since the ultrasonic vibration transmitted without being reflected by the vibration separating member can be attenuated by the core material, vibration noise can be reduced.

  According to a sixth aspect of the present invention, in the ultrasonic sensor according to any one of the first to fourth aspects, the vibration separating member is a one-side member having a higher acoustic impedance than the core material. And a technical means of having a laminated structure formed by being sandwiched between other members.

  According to the invention described in claim 6, the vibration separating member is formed so as to have a laminated structure formed by sandwiching the core material between the one side member and the other side member having higher acoustic impedance than the core material. Can do. According to this, since the difference in acoustic impedance between the one side member and the core material and between the core material and the other side member becomes large, it becomes easy to reflect the ultrasonic wave from the transmitting element at each interface, and vibration noise is reduced. Can be reduced.

  According to a seventh aspect of the present invention, in the ultrasonic sensor according to any one of the first to fourth aspects, the vibration separating member is configured by bonding one side member and the other side member. A technical means is used in which a member to be sealed whose acoustic impedance is lower than that of the one side member and the other side member is sealed in the sealing space.

  According to the seventh aspect of the present invention, the vibration separating member has a lower acoustic impedance than the one side member and the other side member in the sealed space formed by bonding the one side member and the other side member. It can be formed by sealing the sealing member. According to this, since the difference in acoustic impedance between the one-side member and the sealed member and between the sealed member and the other-side member becomes large, it becomes easy to reflect the ultrasonic wave from the transmitting element at each interface. Vibration noise can be reduced. In particular, since it has a sealing structure, a gas such as air or a gel-like substance having a low acoustic impedance can be used as a member to be sealed, the gas has a high compressibility, and the gel-like substance has a large damping constant. Therefore, the transmitted vibration can be absorbed.

  According to an eighth aspect of the present invention, in the ultrasonic sensor according to the seventh aspect, a honeycomb-shaped partition member that divides the sealed space into a plurality of sections is provided in the sealed space. Use technical means.

  According to the eighth aspect of the present invention, a honeycomb-shaped partition member that divides the sealed space into a plurality of partitions can be provided in the sealed space. According to this, it is possible to reduce vibration noise and increase the strength of the vibration separating member.

  According to a ninth aspect of the present invention, in the ultrasonic sensor according to any one of the first to fourth aspects, the vibration separating member is formed by sealing bubbles therein. Use appropriate means.

  According to the ninth aspect of the present invention, the vibration separating member can be formed by sealing bubbles therein. According to this, since the difference in acoustic impedance between the bubble and the other part can be increased, it becomes easy to reflect the ultrasonic wave from the transmitting element, and vibration noise can be reduced. In particular, the manufacturing cost of a vibration separating member having a large difference in acoustic impedance can be reduced by forming the vibration separating member so as to contain bubbles in the manufacturing process thereof.

  According to a tenth aspect of the present invention, in the ultrasonic sensor according to any one of the first to ninth aspects, the first buffer material is made of a material having an elastic modulus lower than that of the first buffer material. A technical means is provided that includes a second cushioning material provided so as to overlap the piezoelectric element and the laminated piezoelectric element.

  According to the invention described in claim 10, the impact applied to each acoustic matching member can be absorbed by the first cushioning material having a high elastic modulus. In addition, by placing a second cushioning material with a low elastic modulus on the side of each acoustic matching member where ultrasonic vibration is large, vibration damping is reduced and the piezoelectric element and the laminated piezoelectric element are protected from environmental factors such as moisture. can do.

  According to an eleventh aspect of the present invention, in the ultrasonic sensor according to the tenth aspect, the elastic modulus is higher than that of the first buffer material instead of the first buffer material provided on the laminated piezoelectric element side. The technical means of using a third buffer material made of a high material is used.

  According to the invention described in claim 11, in place of the first buffer material provided on the laminated piezoelectric element side, the third buffer material formed of a material having a higher elastic modulus than the first buffer material is used. be able to. Since the laminated piezoelectric element formed by lamination has a large driving force, it is difficult to be affected by vibration damping by the buffer material. For this reason, the ultrasonic wave oscillated from the laminated piezoelectric element can be effectively transmitted to the outside by using the third buffer material having a higher elastic modulus than the first buffer material used for the receiving element.

  In the invention described in claim 12, in the ultrasonic sensor according to claim 11, the third buffer material is formed higher than the first buffer material, and the first buffer material is the first buffer material. The technical means that the third buffer material is formed so that the height covering the multilayered piezoelectric element is larger than the height covering the piezoelectric element is used.

  According to the twelfth aspect of the present invention, since the height of the third cushioning material is high, it is possible to restrain and prevent the laminated piezoelectric element from shaking in the lateral direction.

  According to a thirteenth aspect of the present invention, in the ultrasonic sensor according to any one of the first to twelfth aspects, the vibration damping member is a transmission surface that transmits the ultrasonic waves of the first acoustic matching member. And a technical means that the second acoustic matching member is formed so as to cover the receiving surface for receiving the ultrasonic waves.

  According to the invention described in claim 13, the vibration damping member covers the transmission surface for transmitting the ultrasonic waves of the first acoustic matching member and the reception surface for receiving the ultrasonic waves of the second acoustic matching member. Since it is formed, it is possible to block environmental factors such as moisture that deteriorates the transmitting element and the receiving element, so that the reliability of the ultrasonic sensor can be improved.

  In the invention described in claim 14, the ultrasonic sensor according to any one of claims 1 to 13 includes a set of transmitting elements or a set of receiving elements having different directivities. Use technical means.

  According to the fourteenth aspect of the present invention, since a set of transmitting elements or a set of receiving elements having different directivities is provided, a wide detection area can be obtained by properly using directivities according to the surrounding conditions. The obstacle can be detected with high sensitivity.

  According to a fifteenth aspect of the present invention, in the ultrasonic sensor according to any one of the first to fourteenth aspects, a part of the vibration separating member protrudes outward from the other end of the casing. The technical means of forming is used.

  According to the invention described in claim 15, the vibration separating member can be formed such that a part thereof protrudes outward from the other end of the casing. According to this, the resonance frequency of the vibration separating member can be lowered, and the vibration can be drawn out and attenuated by a part protruding in this way, so that vibration noise can be reduced.

  According to a sixteenth aspect of the present invention, in the ultrasonic sensor according to the fifteenth aspect, a part of the vibration separating member protruding outward from the other end of the casing is attenuated and suppressed. The technical means that the vibration suppression member for performing is provided is used.

  According to the invention described in claim 16, a vibration suppressing member for attenuating and suppressing the vibration of this part is provided in a part of the vibration separating member protruding outward from the other end of the housing. Can do. According to this, since the vibration transmitted to the part protruding as described above can be effectively attenuated by the vibration suppressing member, vibration noise can be further reduced.

  According to a seventeenth aspect of the present invention, in the ultrasonic sensor according to any one of the first to sixteenth aspects, the vibration separating member is provided with a vibration having a phase opposite to that of the vibration separating member. The technical means of providing vibration damping means for damping the vibration of the vibration separating member is used.

  According to the seventeenth aspect of the present invention, the vibration attenuating means for attenuating the vibration of the vibration separating member by providing the vibration separating member with a vibration having a phase opposite to that of the vibration separating member is provided. According to this, since the vibration of the vibration separating member can be attenuated by applying the vibration in the opposite phase by the vibration attenuating means, the vibration noise can be reduced.

  According to an eighteenth aspect of the present invention, in the ultrasonic sensor according to any one of the first to seventeenth aspects, the vibration separating member has a technical means that a side surface thereof is formed in an uneven shape. Use.

  According to the invention described in claim 18, the side surface of the vibration separating member is formed in an uneven shape. According to this, since the resonance frequency of the vibration separating member can be changed according to the uneven shape, the resonance of the vibration separating member can be suppressed.

  In the invention according to claim 19, in the ultrasonic sensor according to any one of claims 1 to 17, the vibration separating member is supported by the casing at a peripheral portion thereof. The technical means that the thickness of the peripheral portion is formed to be thinner than the thickness of the central portion is used.

  According to the nineteenth aspect of the present invention, the vibration separating member is supported by the casing at the periphery thereof, and is formed such that the thickness of the periphery is thinner than the thickness of the center portion. can do. According to this, when the vibration from the transmitting element is transmitted to the vibration separating member, only the relatively thin peripheral part vibrates, and the central part excluding the peripheral part is against the side surfaces of the transmitting element and the receiving element. Therefore, the effect of vibration on the receiving element can be suppressed.

  According to a twentieth aspect of the present invention, in the ultrasonic sensor according to any one of the first to seventeenth aspects, the vibration separating member is provided with a technical means that a reinforcing member is provided on a side surface thereof. Use.

  According to the twentieth aspect, the vibration separating member is provided with the reinforcing member on the side surface thereof. According to this, it is possible to reduce vibration noise and increase the strength of the vibration separating member.

  According to a twenty-first aspect of the invention, in the ultrasonic sensor according to the twentieth aspect, a technical means is used in which the reinforcing member is formed in a honeycomb shape with respect to a side surface of the vibration separating member.

  According to the invention as set forth in claim 21, the reinforcing member is formed in a honeycomb shape with respect to the side surface of the vibration separating member. According to this, the strength of the vibration separating member by the reinforcing member can be further increased.

  According to a twenty-second aspect of the present invention, in the ultrasonic sensor according to any one of the first to twenty-first aspects, the vibration damping member includes the first acoustic matching member and the second acoustic matching member. The technical means that one or more notches are formed between the members is used.

  According to the invention described in claim 22, one or a plurality of notches can be formed between the first acoustic matching member and the second acoustic matching member in the vibration damping member. According to this, since the vibration from the first acoustic matching member is dispersed at the notch until the vibration is transmitted to the second acoustic matching member via the vibration damping member, vibration noise can be reduced. .

  According to a twenty-third aspect of the present invention, in the ultrasonic sensor according to any one of the first to twenty-second aspects, the transmitting element includes one transmitting element and a plurality of receiving elements, and each receiving element includes the transmitting element. A technical means is used in which the elements and the vibration separating member are arranged so that the distance between them is equal.

  According to the twenty-third aspect of the present invention, one transmitting element and a plurality of receiving elements are provided, and each receiving element is disposed so that the distance between the transmitting element and the vibration separating member is equal to each other. According to this, since each receiving element is affected by the vibration caused by the transmitting element at the same timing, vibration noise can be easily reduced by performing signal processing.

  According to a twenty-fourth aspect of the present invention, in the ultrasonic sensor according to any one of the first to twenty-second aspects, the transmission element and the plurality of receiving elements are provided, and the vibration separating member has a honeycomb shape. The transmitter is divided into a plurality of compartments, the transmitting elements are arranged in a central compartment, and the receiving elements are transmitted in the other compartments adjacent to the central compartment. A technical means is used in which the elements are individually arranged so that the distances to the elements are equal to each other.

  According to a twenty-fourth aspect of the present invention, there is provided one transmitting element and a plurality of receiving elements, the vibration separating member is formed in a honeycomb shape and divides the inside of the housing into a plurality of sections, and the transmitting element is in the central section. In addition, the receiving elements are individually arranged in the other sections adjacent to the central section so that the distances from the transmitting elements are equal to each other. According to this, since each receiving element is affected by the vibration caused by the transmitting element at the same timing, vibration noise can be easily reduced by performing signal processing. Furthermore, since the vibration separating member is formed in a honeycomb shape, the strength of the vibration separating member can be increased.

[First Embodiment]
A first embodiment of an ultrasonic sensor according to the present invention will be described with reference to the drawings. Here, an ultrasonic sensor mounted on a vehicle and used as an obstacle sensor will be described as an example.
FIG. 1 is an explanatory diagram of the ultrasonic sensor according to the first embodiment. FIG. 1A is an explanatory plan view of the ultrasonic sensor as viewed from the acoustic matching member side, and FIG. 1B is a cross-sectional view taken along the line AA in FIG. FIG. 2 is a longitudinal cross-sectional explanatory view showing a configuration in which the vibration separating member is formed integrally with the housing. 3 and 4 are longitudinal cross-sectional explanatory views showing a modification example of the vibration separating member.
Here, in FIG. 1, the front direction of FIG. 1A and the upward direction of FIG. 1B indicate the outside of the vehicle. Moreover, the ground exists in the downward direction of FIG.
In each figure, for the sake of explanation, a part is enlarged and a part is omitted.

  As shown in FIGS. 1A and 1B, the ultrasonic sensor 10 includes a transmission element 11 that transmits ultrasonic waves, and a detection object (failure) that is transmitted from the transmission element 11 to the front of the vehicle and exists in front of the vehicle. The receiving elements 12p, 12q, and 12r that detect the ultrasonic waves reflected by the object), the vibration attenuating member 18 that prevents the transmission of the ultrasonic waves between the elements, and the transmitting element 11 and the receiving elements 12p, 12q, and 12r are external forces. The first buffer material 19 that protects against a load and an impact, the transmission element 11 is partitioned from the reception elements 12p to 12r, the vibration separating member 90 that shields transmission of ultrasonic waves, the reception elements 12p, 12q, and 12r, and the transmission element 11 And a box-shaped housing 31 having one end opened to accommodate the first cushioning material 19 and the vibration separating member 90.

Since the structures of the receiving elements 12p to 12r are the same, the receiving element 12p will be described here.
The receiving element 12p includes an acoustic matching member 13p that receives an ultrasonic wave oscillated from the transmitting element 11 and reflected by an obstacle and transmits the vibration to the piezoelectric element 14p, and a piezoelectric element 14p that detects the ultrasonic wave. It is formed by bonding.

  The piezoelectric element 14p is made of, for example, lead zirconate titanate (PZT), and a piezoelectric body formed in the shape of a rectangular column whose cross section is equal to the cross section of the acoustic matching member 13p is formed on the opposing surface with Pt. And a pair of electrodes 15p formed by sputtering of Cu or Ag, plating, baking of a conductive paste, or the like. In addition, the piezoelectric element 14p may be formed by being laminated, similarly to the laminated piezoelectric element 16 described later.

  The acoustic matching member 13p is formed using a resin material having excellent durability such as polycarbonate resin having an acoustic impedance larger than that of air and smaller than that of the piezoelectric element 14p.

  The acoustic matching member 13p is formed so that the thickness thereof is about 1/4 of the wavelength in the ultrasonic acoustic matching member 13p. A standing wave can be generated in the acoustic matching member 13p by forming the thickness of the acoustic matching member 13p to be about 1/4 of the wavelength of the ultrasonic wave. As a result, it is possible to reduce the fact that the ultrasonic wave incident into the acoustic matching member 13p and the ultrasonic wave reflected at the interface between the acoustic matching member 13p and the piezoelectric element 14p interfere with each other and cancel each other. An ultrasonic wave can be efficiently transmitted to the element 14p. Further, it is desirable that the width W be equal to or less than half of the wavelength of ultrasonic waves in the air.

  The transmitting element 11 is formed by bonding an acoustic matching member 13 having the same configuration as the receiving element 12p and a laminated piezoelectric element 16 that oscillates ultrasonic waves.

  The laminated piezoelectric element 16 is made of, for example, lead zirconate titanate (PZT), and a pair of electrodes 17 is formed on a piezoelectric body that is formed in a quadrangular prism shape whose cross-sectional outer shape is equal to the cross-sectional outer shape of the acoustic matching member 13p. Are alternately stacked in a comb-like shape. Thus, the laminated piezoelectric element 16 is equivalent to a shape in which a plurality of layers of piezoelectric elements are laminated, and in the present embodiment, it has a shape in which five layers of piezoelectric elements are laminated. Here, the number of stacked piezoelectric elements is variable according to the required sound pressure.

  The electrode 14 of the piezoelectric element 14p and the electrode 17 of the laminated piezoelectric element 16 are electrically connected to circuit elements (not shown) via wires 14a and 17a, respectively. The circuit element is electrically connected to an ECU (Electronic Control Unit: not shown) provided in the vehicle.

Each acoustic matching member 13, 13p to 13r has a vibration dampening member 18 that prevents transmission of ultrasonic waves, and the interval d between the central portions of the adjacent acoustic matching members is substantially equal to the half wavelength of the ultrasonic waves. They are arranged in an array so as to be equal.
However, the interval between the center portions depends on the angle of the detection area, and the angle can be detected even when the interval d is larger than a half wavelength.

  The vibration damping member 18 is fixed to the opening of the casing 31 so as to cover the reception surface 13j of each of the acoustic matching members 13p to 13r and the transmission surface 13s of the acoustic matching member 13. When this configuration is used, the interfaces between the acoustic matching members 13, 13p to 13r and the vibration damping member 18 are not exposed to the outside, so that it is possible to prevent water and the like from entering through the joint surface. The reliability of the acoustic wave sensor can be improved. The casing 31 is attached to a predetermined position of the vehicle, for example, the bumper 100 so that the acoustic matching members 13 and 13p to 13r face outward.

The vibration damping member 18 is made of a material having a smaller acoustic impedance and a higher damping constant than the acoustic matching members 13, 13p to 13r, for example, silicon rubber. Further, a material having a low elastic modulus and a material having a low density are preferably used for the vibration damping member 18. For example, a rubber material, a resin containing pores such as a foamed resin, a sponge, or the like can be used. Since the vibration damping member 18 formed of such a material is interposed between the acoustic matching members 13 and 13p to 13r, an ultrasonic wave is transmitted between the acoustic matching members 13 and 13p to 13r, and noise is transmitted. Can be prevented.
Here, the portion of the vibration attenuating member 18 that covers the receiving surface 13j and the transmitting surface 13s is formed to have a thickness of 1 mm or less, for example, so as not to greatly inhibit the transmission of ultrasonic waves.

  The first buffer material 19 is formed by laminating the transmission element 11 with a material having a lower elastic modulus than the piezoelectric element 14p and the laminated piezoelectric element 16, for example, a polymer material such as a soft resin such as urethane, a potting material such as rubber or silicone. The piezoelectric element 16, the piezoelectric element 14 p of the receiving element 12 p, and the piezoelectric elements (not shown) of the receiving elements 12 q and 12 r are surrounded and provided between the housing 31.

By providing the first buffer material 19 as described above, even when an impact is applied to each of the acoustic matching members 13 and 13p to 13r by a collision of flying objects such as pebbles, the first buffer material 19 is transmitted to the transmitting element. 11 and the receiving elements 12p to 12r are absorbed, and the transmitting element 11 and the receiving elements 12p to 12r are restrained from being displaced toward the bottom surface 31a of the casing 31, The elements 12p to 12r can be protected and destruction can be prevented.
In addition, since environmental factors such as moisture that deteriorate the piezoelectric element 14p and the laminated piezoelectric element 16 can be blocked, the reliability can be improved.

The vibration separating member 90 is formed in a plate shape from a material having a higher elastic modulus and acoustic impedance than the first buffer material 19.
The vibration separating member 90 is provided between the transmitting element 11 and the receiving elements 12p and 12r adjacent to each other, and is erected from the bottom surface 31a of the housing 31. One end of the vibration separating member 90 is fixed by the vibration attenuating member 18, and Is enclosed by surrounding the transmitting element 11. Here, the thickness of the vibration separating member 90 reduces the transmission of ultrasonic vibrations from the laminated piezoelectric element 16 to the acoustic matching members 13p to 13r, and at the vibration damping member 18, the acoustic matching members 13p to 13r. It is set to a thickness that can reduce the vibration inhibition.

Next, detection of an obstacle by the ultrasonic sensor 10 will be described.
First, the circuit element outputs a voltage signal to the laminated piezoelectric element 16 based on a control signal for controlling the sound pressure and phase of the ultrasonic wave output from the ECU. Based on this voltage signal, the laminated piezoelectric element 16 vibrates and oscillates ultrasonic waves having a predetermined sound pressure and phase.

  Here, since the laminated piezoelectric element 16 of the transmitting element 11 is laminated in five layers, for example, when the same voltage is applied as compared with a piezoelectric element having only one layer, the displacement is five times, that is, five times. The sound pressure can be obtained. That is, the laminated piezoelectric element 16 can oscillate ultrasonic waves with high sound pressure.

  Further, since the vibration separating member 90 that partitions the transmission element 11 is formed of a material having a higher elastic modulus and acoustic impedance than the first buffer material 19, the vibration isolation member 90 is transmitted from the laminated piezoelectric element 16 through the first buffer material 19. Ultrasonic waves can be reflected at the interface between the vibration separating member 90 and the first buffer material 19. Thereby, even if an ultrasonic wave with a high sound pressure is oscillated from the transmitting element 11, vibration noise generated by transmitting the ultrasonic wave from the transmitting element 11 to the receiving elements 12p to 12r can be reduced.

  The ultrasonic wave oscillated by the laminated piezoelectric element 16 is transmitted to the acoustic matching member 13 and transmitted from the transmission surface 13s to the outside of the vehicle. The ultrasonic wave transmitted from the transmission surface 13s is reflected by the obstacle, and the reflected ultrasonic wave is received by the reception surface 13j of the acoustic matching member of the reception elements 12p to 12r. For example, the ultrasonic wave received by the receiving surface 13j of the acoustic matching member 13p of the receiving element 12p is transmitted to the piezoelectric element 14p via the acoustic matching member 13p. The ultrasonic wave transmitted to the piezoelectric element 14p is detected by the piezoelectric element 14p and converted into a voltage signal. The voltage signal output from the piezoelectric element 14p is transmitted to the ECU through the circuit element. The circuit element performs arithmetic processing based on the voltage signal output from the piezoelectric element 14p.

Since the receiving elements 12p to 12r are arranged in an array, the time difference between transmission and reception and the time difference or phase difference between the receiving elements 12p to 12r of the received ultrasonic waves are obtained, based on each difference. Thus, the position of the obstacle can be measured.
Here, since the vibration damping member 18 is interposed between the receiving elements 12p to 12r, the ultrasonic waves can be separated and transmitted and detected for each of the receiving elements 13p to 13s. Talk characteristics can be obtained, and ultrasonic detection accuracy can be improved.

(Example of change)
In the present embodiment, the reception surface 13j and the transmission surface 13s are covered by the vibration damping member 18, but the present invention is not limited to this.
For example, the vibration damping member 18 employs a configuration in which the acoustic matching members 13 and 13p to 13r are fixed on the side surfaces near the reception surface 13j and the transmission surface 13s, and the reception surface 13j and the transmission surface 13s are exposed to the outside. You can also. In addition, the exposed receiving surface 13j and transmitting surface 13s in this configuration may be covered with another member such as paint.

The vibration separating member 90 can also be formed integrally with the housing 31. According to this, the number of parts can be reduced, and the positional accuracy of the vibration separating member 90 can be improved.
Further, as shown in FIG. 2, the vibration damping member 18, the casing 31, and the vibration separating member 90 can be bonded via the bonding layer 18 a. Thereby, the positioning accuracy with respect to the transmission element 11 and each receiving element 12p-12r, the housing | casing 31, and the vibration isolation member 90 is securable. The bonding layer 18a can be formed by two-color molding, thermocompression bonding, laser welding, vulcanization adhesion, adhesive, or the like.

  The vibration separating member 90 can be formed so that the acoustic matching member side is thinner than the piezoelectric element side. For example, as shown in FIG. 3, it can be formed so that the longitudinal section has a trapezoidal shape. As a result, the vibration of the acoustic matching member can be prevented from being disturbed, and the strength of the vibration separating member 90 can be increased. In this configuration, if the acoustic matching member side can be formed to be thinner than the piezoelectric element side, the longitudinal section is not limited to a trapezoidal shape, for example, a step shape combining plates having different thicknesses. You can also.

  The vibration separating member 90 can also have a laminated structure in which a soft material is sandwiched between hard materials. For example, as shown in FIG. 4, a configuration in which a core material 90a formed of a resin material is sandwiched between plate materials 90b formed of a metal material can be used. Thereby, since the ultrasonic vibration transmitted without being reflected by the plate member 90b can be attenuated by the core member 90a, vibration noise can be reduced.

  The shape of the first cushioning material 19 is arbitrary as long as it retains the shock-absorbing effect. For example, it can be formed only between the piezoelectric element 14p and the laminated piezoelectric element 16 and the bottom surface 31a of the casing 31, or the entire space inside the casing 31 can be filled.

  The shape of each acoustic matching member 13, 13p to 13r is not limited to a quadrangular prism having a substantially square cross section, and may be a cylinder, for example. According to this, the unnecessary vibration of each acoustic matching member 13, 13p-13r can be suppressed.

  The number and arrangement of transmitting elements and receiving elements are arbitrary depending on the application. For example, if distance detection is performed, one transmitting element and one receiving element may be arranged. For angle detection, one transmitting element and two receiving elements may be arranged. Thereby, the angle detection of the direction which has arrange | positioned the receiving element can be performed.

[Effect of the first embodiment]
(1) Since the ultrasonic sensor 10 of the first embodiment uses a laminated piezoelectric element 16 in which piezoelectric elements are laminated in a plurality of layers and oscillates ultrasonic waves, the transmitting element 11 is used, so that ultrasonic waves with high sound pressure are used. Can oscillate. Further, since the vibration separating member 90 is provided, vibration noise generated by transmitting ultrasonic waves from the transmitting element 11 to the receiving elements 12p to 12r can be reduced. That is, the ultrasonic sensor 10 that can achieve both high sound pressure and low vibration noise can be realized.

(2) The transmission element 11 and the reception elements 12p to 12r can be protected from the load of external force by the first buffer material 19. In addition, since the vibration separating member 90 is formed of a material having an acoustic impedance higher than that of the first buffer material 19, ultrasonic waves transmitted from the laminated piezoelectric element 16 through the first buffer material 19 are transmitted to the vibration separating member. The light can be reflected at the interface between 90 and the first buffer material 19. Thereby, even if an ultrasonic wave with a high sound pressure is oscillated from the transmitting element 11, vibration noise generated by transmitting the ultrasonic wave from the transmitting element 11 to the receiving elements 12p to 12r can be reduced.

(3) In the configuration in which the vibration separating member 90 is formed integrally with the housing 31, the number of parts can be reduced and the positional accuracy of the vibration separating member 90 can be improved. Further, in a configuration in which at least a part is integrally formed, the position accuracy can be improved.

(4) In the configuration in which the vibration separating member 90 is formed so that the acoustic matching member side is thinner than the piezoelectric element side, vibration of the acoustic matching member can be prevented from being inhibited, and the strength of the vibration separating member 90 can be increased. Can be increased.

(5) In the configuration in which the vibration separating member 90 has a laminated structure in which a soft material is sandwiched between hard materials, the transmitted ultrasonic vibration can be attenuated by the core material 90a, so that vibration noise can be reduced.

(6) Since the vibration damping member 18 is formed so as to cover the transmission surface 13s and the reception surface 13j, environmental factors such as moisture that degrade the transmission element 11 and the reception elements 12p to 12r can be blocked. The reliability of the ultrasonic sensor 10 can be improved.

[Second Embodiment]
The ultrasonic sensor of 2nd Embodiment is demonstrated with reference to figures. FIG. 5 is a longitudinal sectional view of the ultrasonic sensor according to the second embodiment. 6 and 7 are longitudinal cross-sectional explanatory views of a modification example of the ultrasonic sensor according to the second embodiment. In addition, about the structure similar to 1st Embodiment, while using the same code | symbol, description is abbreviate | omitted.

  As shown in FIG. 5, the ultrasonic sensor 20 according to the second embodiment is formed of a material having a lower elastic modulus and lower acoustic impedance than the first buffer material 19, for example, a gel, overlapping the first buffer material 19. A second cushioning material 21 is provided. The first buffer material 19 is provided by filling the space between the piezoelectric element 14p and the laminated piezoelectric element 16 and the bottom surface 31a of the housing 31, and the second buffer material 21 is superimposed on the first buffer material 19 and is piezoelectric. It is provided so as to cover the element 14 p and the laminated piezoelectric element 16.

  According to this structure, the impact applied to each acoustic matching member 13 and 13p-13r can be absorbed by the 1st shock absorbing material 19 with a high elastic modulus. Further, the second damping material 21 having a low elastic modulus is arranged on each acoustic matching member 13, 13 p to 13 r side where the vibration of the ultrasonic wave is large, thereby reducing vibration attenuation, and the piezoelectric element 14 p and the laminated piezoelectric element 16. Can be protected from environmental factors such as moisture.

  In addition, a buffer material made of a different material on the piezoelectric element side can be used for the transmitting element 11 and the receiving elements 12p to 12r. As shown in FIG. 6, as a buffer material disposed on the laminated piezoelectric element 16 side, a third buffer material 22 formed of a material having a higher elastic modulus than the first buffer material 19 is used instead of the first buffer material 19. Can be used. Since the laminated piezoelectric element 16 having a laminated structure has a large driving force, the laminated piezoelectric element 16 is not easily affected by vibration attenuation by the buffer material. For this reason, the ultrasonic wave oscillated from the laminated piezoelectric element 16 can be effectively transmitted to the outside by using the third buffer material 22 having a higher elastic modulus than the first buffer material 19 used for the receiving elements 12p to 12r. it can.

  Further, as shown in FIG. 7, the height of the third cushioning material 22 can be formed higher than that of the first cushioning material 19. Thereby, it is possible to restrain and prevent the lateral vibration of the laminated piezoelectric element 16.

[Effects of Second Embodiment]
(1) In the ultrasonic sensor 20 according to the second embodiment, the second buffer material 21 formed of a material having a lower elastic modulus and lower acoustic impedance than the first buffer material 19 is provided so as to overlap the first buffer material 19. Therefore, the impact applied to each of the acoustic matching members 13 and 13p to 13r can be absorbed by the first buffer material 19 having a high elastic modulus. Further, the second damping material 21 having a low elastic modulus is arranged on each acoustic matching member 13, 13 p to 13 r side where the vibration of the ultrasonic wave is large, thereby reducing vibration attenuation, and the piezoelectric element 14 p and the laminated piezoelectric element 16. Can be protected from environmental factors such as moisture.

(2) In the configuration using the third buffer material 22 formed of a material having a higher elastic modulus than that of the first buffer material 19 instead of the first buffer material 19, ultrasonic waves oscillated from the laminated piezoelectric element 16 are externally transmitted. Can communicate effectively.

(3) In the configuration in which the height of the third cushioning material 22 is formed higher than that of the first cushioning material 19, the laminated piezoelectric element 16 can be restrained and prevented from shaking in the lateral direction.

[Third Embodiment]
The ultrasonic sensor of 3rd Embodiment is demonstrated with reference to figures. FIG. 8 is an explanatory plan view of the ultrasonic sensor according to the third embodiment. In FIG. 8, the ground exists in the downward direction in the figure. In addition, about the structure similar to 1st Embodiment, while using the same code | symbol, description is abbreviate | omitted.

  The ultrasonic sensor 30 according to the third embodiment includes two transmitting elements and two receiving elements arranged in the horizontal direction, and either the transmitting element or the receiving element has a different directivity. As shown in FIG. 8A, the receiving elements 12q and 12r are arranged side by side in the horizontal direction with respect to the ground, and the transmitting elements 11a and 11b are arranged in the horizontal direction by being partitioned by the vibration separating member 90 below. Has been placed. Thereby, the vibration noise by transmission element 11a, 11b can be reduced.

  The acoustic matching member 13a of the transmission element 11a is formed so that the cross section is a rectangle that is long in the horizontal direction. Since the directivity of the transmission element becomes wider as the length of the side of the transmission surface becomes shorter, the transmission element 11a has a wide directivity in the vertical direction.

  The acoustic matching member 13a of the transmission element 11a is formed so that the cross section is a rectangle that is long in the horizontal direction. Since the directivity of the transmission element becomes wider as the length of the side of the transmission surface becomes shorter, the transmission element 11a has a wide directivity in the vertical direction.

  The acoustic matching member 13b of the transmission element 11b is formed so that the cross section is a rectangle that is long in the vertical direction. For this reason, the transmitting element 11b has a wide directivity in the horizontal direction.

  Thus, since the transmitting element 11a and the transmitting element 11b have different directivities, they can be used properly according to road conditions. Normally, ultrasonic waves are alternately transmitted by the transmission element 11a and the transmission element 11b. When an ultrasonic wave is transmitted by the transmission element 11a, it is possible to detect an obstacle near the ground surface. When ultrasonic waves are transmitted by the transmission element 11b, obstacles can be detected in a wide range in the horizontal direction.

  Even when there is a large reflected wave from the ground on a rough road or the like and an obstacle cannot be detected when an ultrasonic wave is transmitted by the transmitting element 11a, the obstacle is detected by transmitting the ultrasonic wave by the transmitting element 11b. be able to. Similarly, even in the horizontal direction, there is a large reflected wave from the horizontal direction, and even when it is impossible to detect an obstacle when transmitting the ultrasonic wave by the transmitting element 11b, the ultrasonic wave is transmitted by the transmitting element 11a. Obstacles can be detected. Thus, the transmission element 11a and the transmission element 11b complement each other, and an obstacle can be detected with high sensitivity in a wide detection area.

  In addition, the directivity of the receiving element can be changed as shown in FIG. Since the acoustic matching member 13q of the receiving element 12q is formed so that the cross section is a rectangle that is long in the horizontal direction, the receiving element 12q has a wide directivity in the vertical direction. Since the acoustic matching member 13r of the receiving element 12r is formed to have a rectangular shape with a long cross section in the vertical direction, the receiving element 12q has a wide directivity in the horizontal direction. As described above, since the receiving element 11a and the transmitting element 11b have different directivities, they can be selectively used according to the road conditions and the like as in the configuration shown in FIG.

  In this embodiment, the case where two transmitting elements and two receiving elements are provided in the horizontal direction is illustrated. However, if a plurality of transmitting elements or receiving elements are provided, they have different directivities. Can be configured.

[Effect of the third embodiment]
Since the ultrasonic sensor 30 of the third embodiment includes a set of transmitting elements or a set of receiving elements having different directivities, a wide detection area can be obtained by properly using directivities according to road conditions. The obstacle can be detected with high sensitivity.

[Fourth Embodiment]
An ultrasonic sensor according to a fourth embodiment will be described with reference to the drawings. FIG. 9 is a longitudinal sectional view of the ultrasonic sensor according to the fourth embodiment. 10 and 11 are vertical cross-sectional explanatory views of a modification example of the ultrasonic sensor according to the fourth embodiment. In addition, about the structure similar to 1st Embodiment, while using the same code | symbol, description is abbreviate | omitted.

  As shown in FIG. 9, in the ultrasonic sensor 40 of the fourth embodiment, a vibration separating member 91 is provided instead of the vibration separating member 90. The vibration separating member 91 is formed by laminating the core member 91c so as to be sandwiched between the one-side member 91a and the other-side member 91b having higher acoustic impedance than the core member 91c.

  According to this configuration, since the difference in acoustic impedance between the one-side member 91a and the core member 91c and between the core member 91c and the other-side member 91b is increased, the ultrasonic waves from the transmitting element 11 are reflected at each interface. It becomes easy and vibration noise can be reduced.

  Further, instead of the vibration separating member 91, a vibration separating member 92 shown in FIG. The vibration separating member 92 is a sealed member 92d whose acoustic impedance is lower than that of the one side member 92a and the other side member 92b in a sealed space 92c formed by bonding the one side member 92a and the other side member 92b. Is formed by sealing. Note that the sealing space 92c is formed, for example, by combining lattice-shaped ribs formed on the side surface of the one-side member 92a with the side surface of the flat plate-like other side member 92b.

  Even in this case, the difference in acoustic impedance between the one-side member 92a and the sealed member 92d and between the sealed member 92d and the other-side member 92b becomes large. It becomes easy to reflect sound waves, and vibration noise can be reduced. In particular, since it has a sealing structure, a gas such as air or a gel-like substance having a low acoustic impedance can be used as the sealed member 92d. The gas has a high compressibility and the gel-like substance has a large damping constant. Therefore, the transmitted vibration can be absorbed.

  Furthermore, a honeycomb-shaped partition member that partitions the sealed space 92c into a plurality of partitions may be provided in the sealed space 92c. According to this, vibration noise can be reduced and the strength of the vibration separating member 92 can be increased.

  Further, instead of the vibration separating member 91, a vibration separating member 93 shown in FIG. The vibration separating member 93 is formed by sealing bubbles 93a therein. According to this, since the difference in acoustic impedance between the bubble 93a and the other part can be increased, it becomes easy to reflect the ultrasonic wave from the transmission element 11, and vibration noise can be reduced. In particular, the manufacturing cost of the vibration separating member 93 having a large difference in acoustic impedance can be reduced by forming the vibration separating member 93 so as to include the bubbles 93a therein.

[Effect of Fourth Embodiment]
(1) In the ultrasonic sensor 40 of the fourth embodiment, a vibration separating member 91 is provided in place of the vibration separating member 90, and the core member 91c is more acoustically impedance than the core member 91c. Are stacked so as to be sandwiched between the one side member 91a and the other side member 91b having a high height, the difference in acoustic impedance between the one side member 91a and the core material 91c and between the core material 91c and the other side member 91b is Since each becomes large, it becomes easy to reflect the ultrasonic wave from the transmission element 11 in each interface, and vibration noise can be reduced.

(2) In place of the vibration separating member 91, the sealed space 92c formed by bonding the one side member 92a and the other side member 92b has a lower acoustic impedance than the one side member 92a and the other side member 92b. In the configuration using the vibration separating member 92 formed by sealing the sealing member 92d, the difference in acoustic impedance between the one side member 92a and the sealed member 92d and between the sealed member 92d and the other side member 92b. Therefore, the ultrasonic wave from the transmitting element 11 is easily reflected at each interface, and vibration noise can be reduced. In particular, since it has a sealing structure, a gas such as air or a gel-like substance having a low acoustic impedance can be used as the sealed member 92d. The gas has a high compressibility and the gel-like substance has a large damping constant. Therefore, the transmitted vibration can be absorbed.

(3) Furthermore, by providing a honeycomb-shaped partition member that divides the sealed space 92c into a plurality of partitions in the sealed space 92c, vibration noise is reduced and the strength of the vibration separating member 92 is increased. Can be increased.

(4) In the configuration using the vibration separating member 93 formed by sealing the bubble 93a inside instead of the vibration separating member 91, the difference in acoustic impedance between the bubble 93a and other portions is increased. Therefore, it becomes easy to reflect the ultrasonic wave from the transmission element 11, and vibration noise can be reduced. In particular, the manufacturing cost of the vibration separating member 93 having a large difference in acoustic impedance can be reduced by forming the vibration separating member 93 so as to include the bubbles 93a therein.

[Fifth Embodiment]
An ultrasonic sensor according to a fifth embodiment will be described with reference to the drawings. FIG. 12 is an explanatory view of a longitudinal section of the ultrasonic sensor according to the fifth embodiment. In addition, about the structure similar to 1st Embodiment, while using the same code | symbol, description is abbreviate | omitted.

  As shown in FIG. 12, in the ultrasonic sensor 50 of the fifth embodiment, a housing 31 b and a vibration separating member 94 are provided instead of the housing 31 and the vibration separating member 90. A slit 31c into which a part of the vibration separating member 94 can be inserted is formed on the bottom surface of the housing 31b, and a part of the vibration separating member 94 (hereinafter also referred to as a protruding portion 94a) is a slit of the housing 31b. It is formed so as to pass through 31c and protrude outward. A rubber-like elastic member 51 that functions as a vibration suppressing member for attenuating and suppressing the vibration of the protruding portion 94a is attached to the protruding portion 94a. Instead of the rubber-like elastic member 51, for example, a gel-like member may be attached to the protruding portion 94a.

  According to this configuration, the resonance frequency of the vibration separating member 94 can be lowered, and the vibration can be drawn out and attenuated by the protruding portion 94a protruding in this manner, so that vibration noise can be reduced. Moreover, since the vibration transmitted to the protrusion part 94a can be effectively attenuated by the elastic member 51, vibration noise can be further reduced.

[Effect of Fifth Embodiment]
(1) In the ultrasonic sensor 50 of the fifth embodiment, a housing 31b and a vibration separating member 94 are provided instead of the housing 31 and the vibration separating member 90, and the vibration separating member 94 has a protruding portion 94a. Since it is formed so as to protrude through the slit 31c of the housing 31b, the resonance frequency of the vibration separating member 94 is reduced and vibration is drawn out by the protruding portion 94a thus protruding. Since it can be attenuated, vibration noise can be reduced.

(2) Furthermore, since the elastic member 51 for attenuating and suppressing the vibration of the protrusion 94a is attached to the protrusion 94a, the vibration transmitted to the protrusion 94a by the elastic member 51 is effective. Therefore, vibration noise can be further reduced.

[Sixth Embodiment]
The ultrasonic sensor of 6th Embodiment is demonstrated with reference to figures. FIG. 13 is an explanatory view of a longitudinal section of the ultrasonic sensor according to the sixth embodiment. In addition, about the structure similar to 1st Embodiment, while using the same code | symbol, description is abbreviate | omitted.

  As shown in FIG. 13, in the ultrasonic sensor 60 of the sixth embodiment, the noise canceling actuator 61 that functions as a vibration attenuating means for attenuating the vibration of the vibration separating member 90 includes the vibration separating member 90 and the bottom surface 31 a of the housing 31. It is arranged between. The actuator 61 is electrically connected to a corresponding circuit element (not shown) through a wire 61a, and applies vibrations in the opposite phase to the vibration of the vibration separating member 90 to be detected to the vibration separating member 90. Thus, the vibration of the vibration separating member 90 is attenuated.

  According to this configuration, the vibration of the vibration separating member 90 can be attenuated by applying the vibration in the opposite phase by the actuator 61, so that the vibration noise can be reduced. Further, such a vibration attenuating means is disposed on the back surface of each receiving element 12p, 12q, 12r, and the receiving element 12p, 12q, 12r is given a vibration in an opposite phase to the receiving element 12p, 12q, 12r. , 12q, and 12r can be attenuated. Further, the actuator 61 may adjust the vibration applied to the vibration separating member 90 according to the ultrasonic wave transmitted by the transmitting element 11.

[Effects of Sixth Embodiment]
In the ultrasonic sensor 60 of the sixth embodiment, the actuator 61 that attenuates the vibration of the vibration separating member 90 by providing the vibration separating member 90 with vibration having an opposite phase to the vibration of the vibration separating member 90 is provided. Since the vibration of the vibration separating member 90 can be attenuated by applying the vibration of the opposite phase by the actuator 61, the vibration noise can be reduced.

[Seventh Embodiment]
The ultrasonic sensor of 7th Embodiment is demonstrated with reference to figures. FIG. 14 is an explanatory diagram of the ultrasonic sensor according to the seventh embodiment. FIG. 14A is an explanatory plan view of the ultrasonic sensor as viewed from the acoustic matching member side, and FIG. 14B is a cross-sectional view taken along line AA in FIG. In addition, although the structure which employ | adopts one receiving element 12p is shown with respect to 1st Embodiment, it may apply to the structure which employ | adopts 3 receiving elements 12p, 12q, and 12r similarly to 1st Embodiment. it can. Moreover, about the structure similar to 1st Embodiment, while using the same code | symbol, description is abbreviate | omitted.

  As shown in FIGS. 14A and 14B, in the ultrasonic sensor 70 of the seventh embodiment, a vibration separating member 95 is provided instead of the vibration separating member 90. The vibration separating member 95 has an uneven side surface.

  According to this configuration, since the resonance frequency of the vibration separating member 95 can be changed according to the uneven shape, the resonance of the vibration separating member 95 can be suppressed.

[Effect of the seventh embodiment]
In the ultrasonic sensor 70 of the seventh embodiment, since the side surface of the vibration separating member 95 is formed in an uneven shape, the resonance frequency of the vibration separating member 95 can be changed according to the uneven shape, so that the vibration separating member The resonance of the member 95 can be suppressed.

[Eighth Embodiment]
An ultrasonic sensor according to an eighth embodiment will be described with reference to the drawings. FIG. 15 is an explanatory diagram of the ultrasonic sensor according to the eighth embodiment. FIG. 15A is an explanatory plan view of the ultrasonic sensor as viewed from the acoustic matching member side, and FIG. 15B is a cross-sectional view taken along the line AA in FIG. In addition, although the structure which employ | adopts one receiving element 12p is shown with respect to 1st Embodiment, it may apply to the structure which employ | adopts 3 receiving elements 12p, 12q, and 12r similarly to 1st Embodiment. it can. Moreover, about the structure similar to 1st Embodiment, while using the same code | symbol, description is abbreviate | omitted.

  As shown in FIGS. 15A and 15B, in the ultrasonic sensor 80 of the eighth embodiment, a vibration separating member 96 is provided instead of the vibration separating member 90. The vibration separating member 96 is supported by the casing 31 at the peripheral edge portion 96a, and is formed such that the thickness of the peripheral edge portion 96a is thinner than the thickness of the central portion 96b.

  According to this configuration, when the vibration from the transmission element 11 is transmitted to the vibration separating member 96, only the peripheral portion 96a having a relatively thin thickness vibrates, and the central portion 96b excluding the peripheral portion 96a In addition, since it only reciprocates in parallel as a plane with respect to the side surfaces of the receiving elements 12p, 12q, and 12r, the influence of vibration on the receiving elements 12p, 12q, and 12r can be suppressed.

[Effect of Eighth Embodiment]
In the ultrasonic sensor 80 of the eighth embodiment, the vibration separating member 96 is formed so that the thickness of the peripheral edge portion 96a supported by the housing 31 is thinner than the thickness of the central portion 96b. When the vibration from the transmitting element 11 is transmitted to the vibration separating member 96, only the peripheral portion 96a having a relatively thin thickness vibrates, and the central portion 96b excluding the peripheral portion 96a has the transmitting element 11 and each receiving element 12p, Since it only reciprocates in parallel as a plane with respect to the side surfaces of 12q and 12r, it is possible to suppress the influence of vibration on the receiving elements 12p, 12q and 12r.

[Ninth Embodiment]
The ultrasonic sensor of 9th Embodiment is demonstrated with reference to figures. FIG. 16 is an explanatory diagram of the ultrasonic sensor according to the ninth embodiment. FIG. 16A is an explanatory plan view of the ultrasonic sensor as viewed from the acoustic matching member side, and FIG. 16B is a cross-sectional view taken along the line AA in FIG. In addition, although the structure which employ | adopts one receiving element 12p is shown with respect to 1st Embodiment, it may apply to the structure which employ | adopts 3 receiving elements 12p, 12q, and 12r similarly to 1st Embodiment. it can. Moreover, about the structure similar to 1st Embodiment, while using the same code | symbol, description is abbreviate | omitted.

  As shown in FIGS. 16A and 16B, in the ultrasonic sensor 80a of the ninth embodiment, a plurality of reinforcing members 97 are provided at equal intervals on the side surface of the vibration separating member 90 on the receiving element side. According to this configuration, the vibration separating member 90 is reinforced by the reinforcing members 97, and the strength of the vibration separating member 90 can be increased. The reinforcing member 97 may be provided, for example, on the side surface of the vibration separating member 90 on the transmitting element side, or may be provided in another part.

  Further, the reinforcing member 97 may be formed in a honeycomb shape with respect to the side surface of the vibration separating member 90. According to this, the strength of the vibration separating member 90 by the reinforcing member 97 can be further increased.

[Effects of Ninth Embodiment]
(1) In the ultrasonic sensor 80a of the ninth embodiment, since the plurality of reinforcing members 97 are provided on the side surface on the receiving element side of the vibration separating member 90, the vibration separating member 90 reduces vibration noise and the vibration. The strength of the separating member 90 can also be increased.

(2) Furthermore, by forming the reinforcing member 97 in a honeycomb shape with respect to the side surface of the vibration separating member 90, the strength of the vibration separating member 90 by the reinforcing member 97 can be further increased.

[Tenth embodiment]
The ultrasonic sensor according to the tenth embodiment will be described with reference to the drawings. FIG. 17 is an explanatory diagram of the ultrasonic sensor according to the tenth embodiment. FIG. 17A is an explanatory plan view of the ultrasonic sensor as viewed from the acoustic matching member side, and FIG. 17B is a cross-sectional view taken along the line AA in FIG. In addition, about the structure similar to 1st Embodiment, while using the same code | symbol, description is abbreviate | omitted.

  As shown in FIGS. 17A and 17B, in the ultrasonic sensor 80b of the tenth embodiment, the vibration attenuating member 18 includes the acoustic matching member 13 of the transmitting element 11 and the receiving elements 12p, 12q, and 12r. Notches 18b are formed along the vibration separating member 90 on both sides of the vibration separating member 90 between the acoustic matching members 13p, 13q, and 13r.

  According to this configuration, the vibration from the acoustic matching member 13 is dispersed at the notch 18b until it is transmitted to the acoustic matching members 13p, 13q, and 13r via the vibration damping member 18, thereby reducing vibration noise. be able to. The notch 18b may be formed only on one side of the vibration separating member 90, or a plurality of notches 18b may be formed. Moreover, the notch 18b is not limited to being formed along the vibration separating member 90, and may be formed intermittently at a plurality of locations.

[Effect of the tenth embodiment]
In the ultrasonic sensor 80b according to the tenth embodiment, the vibration damping member 18 has a notch 18b between the acoustic matching member 13 and the acoustic matching members 13p, 13q, and 13r. Is distributed in the notch 18b until it is transmitted to the acoustic matching members 13p, 13q, and 13r via the vibration damping member 18, vibration noise can be reduced.

[Eleventh embodiment]
An ultrasonic sensor according to an eleventh embodiment will be described with reference to the drawings. FIG. 18 is an explanatory plan view of the ultrasonic sensor according to the eleventh embodiment. 19 and 20 are explanatory plan views of modified examples of the ultrasonic sensor according to the eleventh embodiment. 18-20, the ground exists in the downward direction in the figure. In addition, about the structure similar to 1st Embodiment, while using the same code | symbol, description is abbreviate | omitted.

  As shown in FIG. 18, the ultrasonic sensor 80 c according to the eleventh embodiment includes one transmitting element 11 and two receiving elements 12 p and 12 q, and each receiving element 12 p and 12 q includes the transmitting element 11 and the vibration separating member 90. Are arranged such that the distances to each other are equal.

  According to this configuration, the receiving elements 12p and 12q are affected by vibrations from the transmitting element 11 at the same timing, so that vibration noise can be easily reduced by performing signal processing. In addition, as shown in FIG. 19, a plurality of receiving elements (12p, 12q, 12r, 12s) are provided, and each receiving element may be arranged so that the distance from the transmitting element 11 and the vibration separating member 90 is equal to each other. Good.

  In addition, as shown in FIG. 20, a single transmission element 11 and a plurality of reception elements 12 are provided, and a vibration separation member 98 formed in a honeycomb shape instead of the vibration separation member 90 is adopted. The body 31 is divided into a plurality of sections, and the transmitting element 11 is arranged in the central section 98a, and each receiving element 12 is transmitted in the other sections 98b to 98g adjacent to the central section 98a. 11 may be arranged individually such that the distances to 11 are equal to each other. According to this, in addition to reducing vibration noise, since the vibration separating member 98 is formed in a honeycomb shape, the strength of the vibration separating member 98 can be increased.

[Effect of the eleventh embodiment]
(1) The ultrasonic sensor 80c according to the eleventh embodiment includes one transmission element 11 and a plurality of reception elements, and each reception element is disposed so that the distances from the transmission element 11 and the vibration separating member 90 are equal to each other. For this reason, each receiving element is affected by vibration caused by the transmitting element 11 at the same timing, so that vibration noise can be easily reduced by performing signal processing.

(2) Further, the inside of the casing 31 is divided into a plurality of sections by the vibration separating member 98 formed in a honeycomb shape, and the transmitting element 11 is disposed in the central section 98a, and each receiving element is In the other sections 98b to 98g adjacent to the section 98a, they are individually arranged so that the distance from the transmitting element 11 is equal to each other. Therefore, in addition to reducing vibration noise, the vibration separating member 98 is provided with a honeycomb. Therefore, the strength of the vibration separating member 98 can be increased.

[Other Embodiments]
The ultrasonic sensor of the present invention can be used as an ultrasonic sensor for detecting surrounding obstacles by being mounted on a part where there is a high possibility that an impact is applied, such as a robot, in addition to an obstacle sensor of an automobile.

It is explanatory drawing of the ultrasonic sensor of 1st Embodiment. FIG. 1A is an explanatory plan view of the ultrasonic sensor as viewed from the acoustic matching member side, and FIG. 1B is a cross-sectional view taken along the line AA in FIG. It is a longitudinal cross-sectional explanatory drawing which shows the structure by which the vibration isolation | separation member was integrally formed with the housing | casing. It is longitudinal cross-sectional explanatory drawing which shows the example of a change of a vibration isolation | separation member. It is longitudinal cross-sectional explanatory drawing which shows the example of a change of a vibration isolation | separation member. It is a longitudinal cross-sectional explanatory drawing of the ultrasonic sensor of 2nd Embodiment. It is a longitudinal cross-sectional explanatory drawing of the example of a change of the ultrasonic sensor of 2nd Embodiment. It is a longitudinal cross-sectional explanatory drawing of the example of a change of the ultrasonic sensor of 2nd Embodiment. It is a plane explanatory view of the ultrasonic sensor of a 3rd embodiment. It is a longitudinal cross-sectional explanatory drawing of the ultrasonic sensor of 4th Embodiment. It is a longitudinal cross-sectional explanatory drawing of the example of a change of the ultrasonic sensor of 4th Embodiment. It is a longitudinal cross-sectional explanatory drawing of the example of a change of the ultrasonic sensor of 4th Embodiment. It is a longitudinal cross-sectional explanatory drawing of the ultrasonic sensor of 5th Embodiment. It is a longitudinal cross-sectional explanatory drawing of the ultrasonic sensor of 6th Embodiment. It is explanatory drawing of the ultrasonic sensor of 7th Embodiment. FIG. 14A is an explanatory plan view of the ultrasonic sensor as viewed from the acoustic matching member side, and FIG. 14B is a cross-sectional view taken along line AA in FIG. It is explanatory drawing of the ultrasonic sensor of 8th Embodiment. FIG. 15A is an explanatory plan view of the ultrasonic sensor as viewed from the acoustic matching member side, and FIG. 15B is a cross-sectional view taken along the line AA in FIG. It is explanatory drawing of the ultrasonic sensor of 9th Embodiment. FIG. 16A is an explanatory plan view of the ultrasonic sensor as viewed from the acoustic matching member side, and FIG. 16B is a cross-sectional view taken along the line AA in FIG. It is explanatory drawing of the ultrasonic sensor of 10th Embodiment. FIG. 17A is an explanatory plan view of the ultrasonic sensor as viewed from the acoustic matching member side, and FIG. 17B is a cross-sectional view taken along the line AA in FIG. It is a plane explanatory view of an ultrasonic sensor of an 11th embodiment. It is plane explanatory drawing of the example of a change of the ultrasonic sensor of 11th Embodiment. It is plane explanatory drawing of the example of a change of the ultrasonic sensor of 11th Embodiment.

Explanation of symbols

10, 20, 30, 40, 50, 60, 70, 80, 80a to 80c Ultrasonic sensor 11, 11a, 11b Multilayer piezoelectric element 12p, 12q, 12r Acoustic matching member 13 Acoustic matching member (first acoustic matching member)
13p acoustic matching member (second acoustic matching member)
13j Reception surface 13s Transmission surface 14p Piezoelectric element 16 Multilayer piezoelectric element 18 Vibration damping member 18b Notch portion 19 First shock absorbing material 21 Second shock absorbing material 22 Third shock absorbing material 31 Housing 31a Bottom surface 90 to 98 Vibration separating member 90a Core material 90b Board

Claims (24)

A piezoelectric element is formed by laminating a plurality of layers, and includes a laminated piezoelectric element that oscillates an ultrasonic wave, and a first acoustic matching member that transmits an ultrasonic wave oscillated by the laminated piezoelectric element. A transmitting element for transmitting sound waves;
A piezoelectric element that detects an ultrasonic wave reflected by the detected object; and a second acoustic matching member that transmits the ultrasonic wave reflected by the detected object to the piezoelectric element; Each receiving at least one receiving element that receives the ultrasonic waves reflected by the transmitter, and the transmitting element and the receiving element are arranged in an array,
A housing formed in a box shape containing one end for accommodating the transmitting element and the receiving element and opening at least a predetermined object;
Vibration that is provided between each acoustic matching member and the opening of the housing, and that fixes the acoustic matching member to the housing and attenuates vibration transmitted between the acoustic matching members. A damping member;
A vibration separating member that is provided between the transmitting element and an adjacent receiving element, divides the interior of the casing so as to surround the transmitting element, and reduces transmission of ultrasonic vibration from the transmitting element to the receiving element When,
An ultrasonic sensor comprising: A first buffer material provided between the piezoelectric element and the laminated piezoelectric element and a bottom surface and an inner side surface of the housing; and protecting the transmitting element and the receiving element from a load of an external force;
The ultrasonic sensor according to claim 1, wherein the vibration separating member is made of a material having an acoustic impedance higher than that of the first buffer material.   The ultrasonic sensor according to claim 1, wherein at least a part of the vibration separating member is integrally formed with the housing.   4. The ultrasonic sensor according to claim 1, wherein the vibration separating member is formed such that the acoustic matching member side is thinner than the piezoelectric element side. 5.   5. The super vibration isolation member according to claim 1, wherein the vibration isolation member has a laminated structure formed by sandwiching a core material with a material having a higher elastic modulus than the core material. 6. Sonic sensor.   5. The vibration isolation member according to claim 1, wherein the vibration isolation member has a laminated structure formed by sandwiching a core member between one side member and another side member whose acoustic impedance is higher than that of the core member. The ultrasonic sensor according to one.   The vibration separating member is formed by sealing a member to be sealed whose acoustic impedance is lower than that of the one side member and the other side member in a sealing space formed by bonding the one side member and the other side member. The ultrasonic sensor according to any one of claims 1 to 4, wherein:   The ultrasonic sensor according to claim 7, wherein a honeycomb-shaped partition member that divides the sealed space into a plurality of partitions is provided in the sealing space.   The ultrasonic sensor according to any one of claims 1 to 4, wherein the vibration separating member is formed by sealing bubbles therein.   A second shock-absorbing material that is provided so as to overlap the first shock-absorbing material and covers the piezoelectric element and the laminated piezoelectric element by a material having a lower elastic modulus than the first shock-absorbing material; The ultrasonic sensor according to any one of claims 1 to 9, wherein the ultrasonic sensor is provided.   The third buffer material formed of a material having a higher elastic modulus than the first buffer material is used instead of the first buffer material provided on the laminated piezoelectric element side. The ultrasonic sensor as described in.   The third cushioning material is formed higher than the first cushioning material, and the third cushioning material covers the laminated piezoelectric element from a height at which the first cushioning material covers the piezoelectric element. The ultrasonic sensor according to claim 11, wherein the ultrasonic sensor is formed to have a larger height.   The vibration damping member is formed so as to cover a transmission surface that transmits ultrasonic waves of the first acoustic matching member and a reception surface that receives ultrasonic waves of the second acoustic matching member. The ultrasonic sensor according to any one of claims 1 to 12.   The ultrasonic sensor according to any one of claims 1 to 13, further comprising a set of transmitting elements or a set of receiving elements having different directivities.   The ultrasonic sensor according to any one of claims 1 to 14, wherein a part of the vibration separating member projects outward from the other end of the casing. .   The vibration suppressing member for attenuating and suppressing the vibration of this part is provided in a part of the vibration separating member protruding outward from the other end of the casing. Ultrasonic sensor.   17. The apparatus according to claim 1, further comprising a vibration attenuating unit that attenuates the vibration of the vibration separating member by applying a vibration having an opposite phase to the vibration of the vibration separating member to the vibration separating member. Ultrasonic sensor described in 1.   The ultrasonic sensor according to claim 1, wherein a side surface of the vibration separating member is formed in an uneven shape.   2. The vibration separating member is supported by the casing at a peripheral edge portion thereof, and is formed so that a thickness of the peripheral edge portion is thinner than a thickness of a central portion. The ultrasonic sensor according to claim 17.   The ultrasonic sensor according to claim 1, wherein a reinforcing member is provided on a side surface of the vibration separating member.   The ultrasonic sensor according to claim 20, wherein the reinforcing member is formed in a honeycomb shape with respect to a side surface of the vibration separating member.   The vibration damping member has one or more notches formed between the first acoustic matching member and the second acoustic matching member. The ultrasonic sensor as described in any one. One transmission element and a plurality of the reception elements,
The ultrasonic sensor according to any one of claims 1 to 22, wherein each of the receiving elements is disposed so that a distance from the transmitting element and the vibration separating member is equal to each other. One transmission element and a plurality of the reception elements,
The vibration separating member is formed in a honeycomb shape and divides the housing into a plurality of sections,
The transmitting elements are arranged in a central section, and the receiving elements are individually arranged in the other sections adjacent to the central section so that the distances to the transmitting elements are equal to each other. The ultrasonic sensor according to any one of claims 1 to 22, wherein the ultrasonic sensor is characterized in that:

Images