JP4860797B2 - Ultrasonic sensor and obstacle detection device - Google Patents

Description

  The present invention relates to an ultrasonic sensor including a plurality of receiving piezoelectric vibrators and an obstacle detection device that detects an obstacle using the ultrasonic sensor.

  Conventionally, as disclosed in, for example, Patent Document 1, an ultrasonic sensor including a plurality of receiving piezoelectric vibrators is known.

The ultrasonic sensor disclosed in Patent Document 1 includes a plurality of piezoelectric elements including at least one transmitting piezoelectric element and at least two receiving piezoelectric elements, and one vibration case that houses the piezoelectric element. ing. The vibration case is provided with a plurality of storage recesses having a bottom surface along the incident / exit surface, and the piezoelectric elements are arranged in contact with the bottom surfaces of the corresponding storage recesses. In addition, a partition recess is provided in a portion of the vibration case between the storage recess in which the transmitting piezoelectric element is stored and the storage recess in which the receiving piezoelectric element is stored.
JP 2004-253911 A

  By the way, as a method of detecting the direction of the obstacle, a method of detecting based on the phase difference of the reception signal of each receiving piezoelectric element is detected based on the time difference of the reception signal of each receiving piezoelectric element. It is known that detection can be performed with higher accuracy than the method. For example, when the frequency of the ultrasonic wave is 40 kHz (wavelength λ 8.5 mm), the vibration surface necessary for the ultrasonic sensor (the surface that vibrates due to the vibration of the piezoelectric element and / or the reflected wave, and is almost equal to the back surface of the bottom surface of the housing recess. ) Is generally about 10 mm considering the rigidity (impact resistance against stepping stones) of the vibration plate (vibration case portion where the piezoelectric element is in contact). Moreover, it is preferable that the adjacent vibration surfaces are separated acoustically. Therefore, in the case of the ultrasonic sensor disclosed in Patent Document 1, in the direction along the incident / exit surface, the distance between the vibration surfaces corresponding to the adjacent receiving piezoelectric elements (distance between the centers) exceeds 10 mm. The wavelength λ of the ultrasonic wave is exceeded. That is, even if the orientation of the obstacle is detected based on the phase difference of the plurality of receiving piezoelectric elements, a range (for example, ± 90 degrees in the direction horizontal to the road surface (180 degrees centered on the vibration surface)) ( (Wide range) cannot be detected, and only a narrow range can be detected, whereas it is conceivable to reduce the vibration surface so that a wide range can be detected. Since the thickness of the plate must be reduced and the rigidity of the diaphragm is lowered, it is difficult to ensure impact resistance.

  Further, when the ultrasonic sensor disclosed in Patent Document 1 is attached to, for example, a bumper of a vehicle, an incident / exit surface including at least a rear surface of a bottom surface of a storage recess and a portion between the storage recesses is provided on the bumper. It will be exposed outside the vehicle through the formed through hole. That is, the part exposed to the outside is large, which is not preferable in appearance.

  The present invention has been made in view of the above problems, and an object thereof is to provide an ultrasonic sensor and an obstacle detection device that can improve the appearance and can detect the azimuth based on the phase difference over a wide range without reducing the impact resistance. .

In order to achieve the above object, an ultrasonic sensor according to claim 1 is characterized in that at least one transmission piezoelectric vibrator for transmitting ultrasonic waves as a transmission wave and reflection of the transmission wave by an obstacle outside the moving body. A plurality of receiving piezoelectric vibrators that receive a wave and output a reception signal corresponding to the intensity of the reflected wave, and a piezoelectric vibrator, respectively, where the piezoelectric vibrator contacts the inner surface of the bottom surface The housing is fixed and the outer surface of the bottom surface portion is a vibration surface, and one open end is exposed to the outside through a through-hole formed in the mounted portion of the moving body. A waveguide for guiding ultrasonic waves to and from the vibration surface arranged inside, and a plurality of waveguides are provided corresponding to at least the receiving piezoelectric vibrator, and the opening area of the opening end is A vibrating surface that is smaller than the area of the vibrating surface and that has an adjacent opening interval between adjacent openings Narrower than the interval, the reflected wave are respectively set to a length which is transmitted to the vibration surface while maintaining a phase difference of each other in the mounting portion, in a plurality of waveguides, each open end, the opening shape Are different in length in the x direction and the y direction, which are two axial directions perpendicular to the opening surface, and the opening shape of the opening end is set to a plurality, and the opening end is more in the y direction than the x direction. The opening end has a narrow opening width and the opening end has an opening width narrower in the x direction than in the y direction .

As described above, according to the present invention, at least a waveguide that induces ultrasonic waves between the attached portion and the housing is received instead of using the vibration surface of the housing as a transmission / reception surface in the attached portion of the moving body. By providing a plurality of piezoelectric vibrators corresponding to the piezoelectric vibrators for use, the opening surface of one opening end of the waveguide is used as a transmission / reception surface. Further, the opening area of the opening end of the waveguide is made smaller than the area of the vibration surface, and the opening interval of the adjacent opening ends of the waveguide is made smaller than the interval of the adjacent vibration surfaces. By adopting such a waveguide, the exposed portion of the ultrasonic sensor exposed to the outside from the attached portion of the moving body can be made smaller than before, and the appearance (designability) can be improved. In addition, each length of the waveguide is set to a length in which the reflected waves are transmitted to the vibration surface while maintaining the mutual phase difference at the attached portion (for the length of one waveguide, Since the lengths of the other waveguides are the same or set to a length shifted by nλ (n: positive integer, λ: wavelength of ultrasonic wave), it is possible to detect the azimuth by the phase difference. In addition, since the opening interval between the adjacent opening ends of the waveguide is made narrower than the interval between the adjacent vibration surfaces, it is possible to perform azimuth detection based on the phase difference in a wider range than in the past. Furthermore, since the opening surface of one opening end of the waveguide is used as a transmission / reception surface, it is possible to detect the azimuth based on the phase difference in a wide range without reducing the impact resistance by using the sensor. Moreover, since the opening shape is set to a plurality (at least one is different from the others), the directivity can be switched according to the opening shape. In particular, in the present invention, the opening shape of each opening end has a different length in the biaxial direction perpendicular to the opening surface, and the opening end has an opening end whose opening width in the y direction is narrower than the x direction. , And an opening end whose opening width in the x direction is narrower than that in the y direction. Therefore, it is possible to detect an obstacle and its direction in a wide range in each of the two axial directions by combining opening ends having different directivities in the two axial directions. Even if the obstacle is relatively displaced, the obstacle and its direction can be detected.

According to a second aspect of the present invention, an opening end whose opening width in the y direction is narrower than the x direction and an opening end whose opening width in the x direction is narrower than the y direction are arranged in the x direction and the y direction, respectively. It is better to have a configuration According to this, an obstacle and its direction can be detected in a wider range in the biaxial direction. Further, as described in claim 3, a plurality of tube portions may be formed on the same base material made of a resin material, and all the waveguides may be integrated. According to this, while simplifying a structure, the positional accuracy of each waveguide can be improved. On the other hand, as described in claim 4, the waveguide may be divided into a plurality of parts corresponding to the receiving piezoelectric vibrator. According to this, the unnecessary vibration transmitted between the waveguides can be reduced. As described in claim 5, when the unnecessary vibration reducing member having an acoustic impedance different from that of the material constituting the waveguide is disposed between the plurality of separated waveguides, the unnecessary vibration is generated. Can be effectively reduced.

According to a sixth aspect of the present invention, in at least one waveguide, the opening area of the opening end on the attached portion side may be smaller than the opening area of the opening end on the vibration surface side. According to this, especially a reflected wave (received wave) can be efficiently transmitted from the opening end on the attached portion side to the vibration surface. Further, the appearance (designability) can be further improved.

Further, as described in claim 7 , in at least one waveguide, the opening area of the opening end on the attached portion side may be larger than the opening area of the opening end on the vibration surface side. According to this, especially a transmission wave can be efficiently transmitted from the vibration surface to the opening end on the attached portion side.

Furthermore, as described in claim 8 , in at least one waveguide, the cross-sectional shape and the cross-sectional area between the opening end on the attachment portion side and the opening end on the vibration surface side are constant. It is also good. According to this, a transmission wave or a reflected wave can be efficiently transmitted between the vibration surface and the opening end on the attached portion side.

According to a ninth aspect of the present invention, at least one of the plurality of piezoelectric vibrators may serve as both transmitting and receiving. According to this, the number of piezoelectric vibrators can be reduced and the cost can be reduced. In addition, the size of the sensor can be reduced.

As described in claim 10 , the lengths of the plurality of waveguides may all be set equal. According to this, the physique of a sensor can be reduced in size.

According to the eleventh aspect of the present invention , the open end of the waveguide may be flush with the outside of the attached portion. According to this, appearance (designability) can be further improved.

According to a twelfth aspect of the present invention, it is preferable that an opening interval between adjacent opening ends is a half wavelength or less with respect to the wavelength of the ultrasonic wave. According to this, it becomes possible to detect a wide range of ± 90 degrees or more with respect to the central axis of the vibration surface. For example, if the mounted portion of the moving body is a plane, almost the entire area in the arrangement direction of the receiving piezoelectric elements can be set as the direction detection area. Further, the side lobes (sub-poles) can be canceled out to reduce or prevent the erroneous detection of obstacles.

According to a thirteenth aspect of the present invention, two or more transmissions may be used as piezoelectric vibrators, and ultrasonic waves may be transmitted simultaneously from a plurality of transmission piezoelectric vibrators. According to this, since the sound pressure can be increased as compared with the configuration having one transmission piezoelectric vibrator, the directivity can be narrowed and the detection distance can be increased. A waveguide is also provided for a plurality of transmission piezoelectric vibrators. With the structure according to claim 12 , the side lobes (sub-poles) cancel each other and the directivity can be further narrowed. .

According to a fourteenth aspect of the present invention, it is preferable that the lower opening position of the opening end on the attached portion side is lower in the gravity direction than the lower opening position of the opening end on the vibration surface side. According to this, it is possible to reduce entry of foreign matter into the waveguide and adhesion to the waveguide.

According to a fifteenth aspect of the present invention , the tubular interior of the waveguide may be filled with an acoustic matching member having an acoustic impedance between the external atmosphere of the moving body and the bottom surface of the housing. According to this, the reflection loss of the ultrasonic wave based on the acoustic impedance difference can be reduced, and the detection sensitivity can be improved. In addition, since foreign matter can be prevented from entering or adhering to the waveguide, false detection due to foreign matter can be reduced, and impact resistance can be improved.

The invention according to claim 15 any one, as claimed in claim 16, the moving body is a vehicle, suitable for the configuration of the ultrasonic sensor is attached to the bumper or body of the vehicle is there.

In addition, the ultrasonic sensor according to any one of claims 1 to 16 is characterized in that, as described in claim 17 , the direction of the obstacle is based on the phase difference of the reception signals of the plurality of reception piezoelectric vibrators. It is suitable as a component of an obstacle detection device characterized by detecting In other words, the obstacle detection device including the ultrasonic sensor having the above-described configuration can perform azimuth detection based on the phase difference over a wide range based on the above-described effects.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(First embodiment)
1A and 1B are diagrams illustrating a schematic configuration of an ultrasonic sensor according to a first embodiment of the present invention, in which FIG. 1A is a plan view and FIG. 1B is a cross-sectional view taken along line AA in FIG. . FIG. 2 is an enlarged cross-sectional view around the housing in FIG. 1A and 1B show a state in which the ultrasonic sensor is attached to the attachment portion of the moving body, and FIG. 1A is a plan view viewed from the outside of the moving body. It is.

  In this embodiment, an example in which an ultrasonic sensor and an obstacle detection device including the sensor are used in a vehicle as a moving body will be described. Specifically, as shown in FIGS. 1A and 1B, the ultrasonic sensor 100 can detect, for example, the front, rear, or four corner sides of the vehicle so as to detect obstacles around the vehicle. It is attached to a bumper or body (bumper 10 in FIGS. 1A and 1B).

  As shown in FIGS. 1A and 1B, the ultrasonic sensor 100 mainly includes a plurality of piezoelectric vibrators 110, a housing 120 that accommodates the piezoelectric vibrators 110, the outside of the vehicle, the piezoelectric vibrators 110, and the like. The waveguide 130 etc. which guide | induce an ultrasonic wave between are comprised.

  The piezoelectric vibrator 110 uses piezoelectric ceramics such as barium titanate or PZT as a sintered body, and generates a vibration by applying a voltage. The piezoelectric vibrator 110 is formed in a disk shape, for example. In the present embodiment, a total of four piezoelectric vibrations, two in the horizontal direction (x direction shown in FIG. 1A) and two in the vertical direction (y direction shown in FIG. 1A) with respect to the road surface. A child 110 is included as one ultrasonic sensor 100. Each of the four piezoelectric vibrators 110 receives a transmission vibrator that transmits ultrasonic waves as a transmission wave to the outside of the vehicle, and a reflected wave of an obstacle existing outside the vehicle, thereby increasing the intensity of the reflected wave. It is configured to also serve as a receiving vibrator that outputs a corresponding received signal. Thus, when at least one of the plurality of piezoelectric vibrators 110 is configured to serve both for transmission and reception, the number of piezoelectric vibrators 110 can be reduced and the cost can be reduced. Moreover, the physique of the ultrasonic sensor 100 can be reduced in size.

  In the present embodiment, ultrasonic waves are transmitted from the plurality of piezoelectric vibrators 110 at the same time. As described above, when two or more transmission piezoelectric vibrators 110 are provided and ultrasonic waves are simultaneously transmitted from the plurality of piezoelectric vibrators 110, the transmission piezoelectric vibrator 110 is provided with one transmission vibrator 110. Sound pressure can be earned in comparison. That is, the directivity can be narrowed and the detection distance can be increased.

  An electrode (not shown) is formed on the surface of the piezoelectric vibrator 110, and a lead 111 is electrically connected to the electrode. In the present embodiment, as shown in FIG. 2, one lead 111 is connected to the inner surface of the casing 120 that is electrically connected to the electrode. The lead 111 outputs a drive signal for generating an ultrasonic wave by vibrating the piezoelectric vibrator 110, or when the ultrasonic wave is transmitted to the piezoelectric vibrator 110 and the piezoelectric vibrator 110 is distorted. In addition, it is electrically connected to a circuit board (not shown) on which a processing circuit for inputting a voltage signal generated by the piezoelectric effect is formed. That is, the ultrasonic sensor 100 is configured as a part of an obstacle detection device including the ultrasonic sensor 100, and the obstacle detection device is arranged around the vehicle based on the time from transmission to reception of the ultrasonic wave. In addition, the distance to the obstacle existing in the head can be calculated, and the direction of the obstacle can be calculated based on the phase difference of the received signals from the plurality of piezoelectric vibrators 110.

  The housing 120 is provided in a bottomed cylindrical shape using, for example, aluminum or synthetic resin (aluminum in the present embodiment) as a constituent material in order to accommodate one piezoelectric vibrator 110. As shown in FIG. 2, the piezoelectric vibrator 110 is installed (for example, fixed) on the inner surface 122 of the bottom surface portion 121. That is, the bottom surface portion 121 on which the piezoelectric vibrator 110 is disposed serves as a diaphragm, and the outer surface 123 (the back surface of the inner surface 122) of the bottom surface portion 121 is a vibration surface. In the present embodiment, the outer surface 123 as the vibration surface is circular in the plane direction of the bumper 10 (direction along the road surface) as shown by a broken line in FIG.

  Further, as shown in FIG. 2, a sound absorbing material 112 is arranged around the piezoelectric vibrator 110 except for a surface facing the inner surface 122. The sound absorbing material 112 is for absorbing ultrasonic waves radiated into the housing 120 when the piezoelectric vibrator 110 expands and contracts and the bottom surface portion 121 of the housing 120 vibrates. It is made of a material with excellent sound absorption performance. And the sealing material 113 is arrange | positioned on the sound absorption material 112, and the inside of the housing | casing 120 is airtightly sealed by this sealing material 113.

  The waveguide 130 guides ultrasonic waves between the outside of the vehicle and the piezoelectric vibrator 110 (the outer surface 123 as the vibration surface) disposed inside the vehicle (the inner surface 11 side of the bumper 10) (in this embodiment). The transmission wave is guided from the outer surface 123 to the outside of the vehicle, and the reflected wave is guided to the outer surface 123). In the waveguide 130 according to the present embodiment, a plurality of tube portions 132 are formed on the same base material 131. The tube portion 132 corresponds to the waveguide described in the claims. As shown in FIG. 1B, one open end 133 of the pipe portion 132 is open on one surface of the base material 131 and is attached to the bumper 10 through the through hole 13 of the bumper 10. It is exposed outside the vehicle. The other opening end 136 is connected to a fixing groove 134 formed on the opposite surface side of the opening end 133 forming surface of the base material 131. The fixing groove 134 is a groove to which the housing 120 including the piezoelectric vibrator 110 is fixed. In the state where the housing 120 is fixed to the fixing groove 134, the open end 136 of the tube portion 132 is formed on the outer surface 123. It is in the state arrange | positioned at the opening end 133 side with some clearance gap between. Thus, in the pipe part 132, the opening end 133 is an opening end on the attached part side described in the claims, and the opening end 136 is an opening end on the vibration surface side.

As a constituent material of the waveguide 130 (base material 131), the difference in acoustic impedance between the outside of the vehicle and the medium (air) in the tube portion 132 is large (for example, 1 × 10 ² or more), and the tube portion 132 is configured. Any material that can efficiently reflect ultrasonic waves on the wall surface of the substrate 131 can be used. Acoustically preferably, the material is different from that of the housing 120. Specifically, a metal material, a resin material, rubber or the like can be employed. As shown in the present embodiment, in a configuration in which a plurality of waveguides (tube portions 132) are integrated, formation is easy when a resin material is selected.

  As shown in FIG. 1A, the plurality of tube portions 132 (in other words, waveguides) have an opening area of each opening end 133 smaller than an area of the outer surface 123 as a corresponding vibration surface. Is set to In the present embodiment, while satisfying the above-described conditions, all of the open ends 133 are circular with the same shape and size, and the corresponding outer surfaces 123 are also set to have the same shape and size. . Further, in all the pipe sections 132, the opening area of the opening end 136 on the vibration surface side is substantially the same as that of the vibration surface (outer surface 123), and the opening area of the opening end 133 on the bumper 10 side is the opening area of the opening end 136. Has been smaller than. And in all the pipe parts 132, the cross-sectional shape between the opening end 133 on the bumper 10 side and the opening end 136 on the vibration surface (outer surface 123) side is a circular shape, and the area (tube diameter) of the circular cross section is the same. It increases from the opening end 133 toward the opening end 136 (vibration surface).

  Further, as shown in FIG. 1A, the opening interval d (dx, dy) between the adjacent opening ends 133 is set to be smaller than the corresponding interval D (Dx, Dy) between the adjacent outer surfaces 123. Yes. In the present embodiment, the opening interval d (dx) in the horizontal direction (x direction shown in FIG. 1A) and the vertical direction (y direction shown in FIG. 1A) is satisfied with respect to the road surface while satisfying the above-described conditions. , Dy) are set equal. Further, the aperture interval d is set to a half wavelength or less (in this embodiment, a half wavelength) with respect to the wavelength of the ultrasonic wave.

  Further, the lengths of the respective tube portions 132 (so that the reflected waves by the obstacles are transmitted to the outer surface 123 as the vibration surface while maintaining the mutual phase difference at the bumper 10 (ultrasonic wave transmission / reception surface). The distance from the open end 133 to the outer surface 123 is set. In order to transmit the signals while maintaining the mutual phase difference, when the length of one tube portion 132 is L, the length of the other tube portion 132 is the same as L or L + nλ (n: a positive integer, (λ: wavelength of the ultrasonic wave) may be set to a shifted length. In the present embodiment, the lengths of the plurality of pipe portions 132 are all set equal.

  The waveguide 130 configured as described above is fixed to the bumper 10 in a state where the casing 120 including the piezoelectric vibrator 110 is fixed to the fixing groove 134. In the present embodiment, a part of the base material 131 including the opening 133 is inserted into the through hole 13 of the bumper 10, and the portion of the base material 131 that faces the inner surface 11 of the bumper 10 is bonded and fixed to the inner surface 11. ing. In this fixed state, the opening end 133 (one surface of the base material 131) is flush with the outer surface 12 of the bumper 10. The housing 120 including the piezoelectric vibrator 110 is fixed to the corresponding fixing groove 134 via the vibration absorbing member 124 so that the outer surface 123 as a vibration surface is on the opening end 133 side. That is, the bottom surface portion 121 as a diaphragm is not in direct contact with the base material 131 (opening end 136 of the tube portion 132) constituting the waveguide 130, and the base material 131 suppresses vibration of the bottom surface portion 121. It is supposed not to. The vibration absorbing member 124 is for reducing unnecessary vibration transmitted between the housing 120 (bottom surface portion 121) and the waveguide 130 (base material 131). For example, the vibration absorbing member 124 is made of silicon rubber or polyurethane. It is configured. In addition, the code | symbol 135 shown to FIG.

  As described above, according to the ultrasonic sensor 100 and the obstacle detection device including the ultrasonic sensor 100 according to the present embodiment, the vibration surface (outer surface 123) of the housing 120 is not the transmission / reception surface of the bumper 10 of the vehicle. In addition, by providing a plurality of pipe portions 132 (waveguides) for guiding ultrasonic waves between the bumper 10 and the outer surface 123 (piezoelectric vibrator 110) corresponding to the piezoelectric vibrator 110, the open end of the pipe portion 132 is provided. The opening surface of 133 is a transmission / reception surface. In addition, the opening area of the opening end 133 of the pipe portion 132 is made smaller than the area of the vibration surface (outer surface 123), and the opening interval d (dx, dy) between the adjacent opening ends 133 is set between the adjacent vibration surfaces (outer surface 123). It is narrower than the interval D (Dx, Dy). Therefore, the exposed part of the ultrasonic sensor 100 exposed to the outside from the bumper 10 of the vehicle can be made smaller than before, and the appearance (designability) can be improved. In particular, in the present embodiment, the opening area of the opening end 133 on the bumper 10 side is made smaller than the opening area of the opening end 136, so that the appearance can be further improved.

  In addition, each length of the tube part 132 is set to a length in which the reflected waves are transmitted to the vibration surface (outer surface 123) while maintaining the mutual phase difference in the bumper 10, so that the direction due to the phase difference is set. Detection is possible. In particular, in the present embodiment, since the lengths of the plurality of pipe portions 132 are all equal, the physique of the sensor can be reduced in size. Furthermore, since the opening interval d of the adjacent opening ends 133 is made narrower than the interval D of the adjacent vibration surfaces (outer surface 123), it is possible to detect the azimuth by the phase difference in a wider range than before. In particular, since the opening interval d of the opening end 133 is set to a half wavelength or less with respect to the wavelength of the ultrasonic wave, the direction of the obstacle is detected in a wide range of ± 90 degrees or more with respect to the central axis of the vibration surface (outer surface 123). It is possible. With such a configuration, as in the bumper 10, when the attachment portion to which the ultrasonic sensor 100 is fixed is a plane, the entire area of the arrangement direction of the plurality of piezoelectric vibrators 110 (for reception) is in the direction detection area. It can be. Further, the side lobes (sub-poles) cancel each other, and the misdirection detection of the obstacle can be reduced or prevented. Thus, by using the waveguide 130, the opening surface of the opening end 133 is used as a transmission / reception surface, so that the rigidity of the housing 120 is not reduced (that is, the impact resistance against a stepping stone or the like is not reduced). It is possible to detect azimuth by phase difference in a wide range.

  Moreover, since the opening surface of the opening end 133 of the pipe part 132 is used as the transmission / reception surface, the collision of the foreign matter with the vibration surface (outer surface 123) of the housing 120 can be reduced. That is, it is possible to reduce the risk of damage to the bottom surface portion 121 of the housing 120 and the piezoelectric vibrator 110 due to the collision of foreign matter (particularly stepping stones) (impact resistance can be improved as the ultrasonic sensor 100).

  In the present embodiment, an example in which a plurality of piezoelectric vibrators 110 having a transmission function are provided and ultrasonic waves are simultaneously transmitted from the plurality of piezoelectric vibrators 110 for transmission has been described. According to this, since the sound pressure can be increased as compared with the configuration having one transmission piezoelectric vibrator 110, the directivity can be narrowed and the detection distance can be lengthened.

  In addition, an example is shown in which each piezoelectric vibrator 110 has both a transmission function and a reception function. However, a configuration including the piezoelectric vibrator 110 having only a transmission function or a reception function may be employed. The waveguide 130 may be disposed corresponding to at least the receiving piezoelectric vibrator 110. As shown in the present embodiment, when the waveguide 130 is disposed also for the transmission piezoelectric vibrator 110 (also used for transmission / reception in the present embodiment), transmission is performed depending on the shape and size of the open end 133. Wave directivity can also be controlled. Furthermore, when the transmission interval of the opening end 133 is set to a half wavelength or less with respect to the wavelength of the ultrasonic wave while having a plurality of transmission piezoelectric vibrators 110, the side lobes (sub-poles) cancel each other and directivity is improved. It can be narrower.

  In the present embodiment, the opening shape and the size of the opening 133 are made equal in each tube portion 132. Therefore, the side lobe (sub-pole) can be canceled out neatly, so that the composite directivity can be easily controlled.

  In the present embodiment, the case 120 including the piezoelectric vibrator 110 is fixed to the base 131 of the waveguide 130 via the vibration absorbing member 124. However, when the base material 131 is made of a material that hardly transmits unnecessary vibration (for example, rubber), the vibration absorbing member 124 can be omitted.

  Further, in the present embodiment, an example in which the opening area of the opening end 136 on the vibration surface side is substantially the same as that of the vibration surface (outer surface 123) is shown. However, the opening area of the opening end 136 on the vibration surface side may be smaller than the vibration surface (outer surface 123). Also in this case, a configuration may be adopted in which a slight gap is provided between the outer surface 123 and the opening end 136 so as not to suppress the vibration of the bottom surface portion 121 as a diaphragm and to prevent leakage of ultrasonic waves. .

  Moreover, in this embodiment, the example which the base material 131 (opening end 136 of the pipe part 132) is not contacted with the outer surface 123 which is a vibration surface was shown. However, the base material 131 (the open end 136 of the pipe portion 132) is in contact with a part of the outer surface 123, and a part other than the part of the outer surface 123 where the vibration is restrained by the base material 131 is used as the vibration surface. Also good.

  Moreover, in this embodiment, although the cross-sectional shape of the pipe part 132 was shown circular, the cross-sectional shape of the pipe part 132 is not limited to the said example. For example, a rectangular shape or a polygonal shape other than a rectangle may be used. However, since the interference of ultrasonic waves can be reduced as it approaches the circle, it is preferable to use a circular cross section as shown in this embodiment.

(Second Embodiment)
Next, a second embodiment of the present invention will be described based on FIG. 3A and 3B are diagrams illustrating a schematic configuration of the ultrasonic sensor 100 according to the second embodiment, in which FIG. 3A is a plan view and FIG. 3B is a cross-sectional view taken along line BB in FIG. 3 (a) and 3 (b) correspond to FIGS. 1 (a) and 1 (b), respectively.

  The ultrasonic sensor 100 according to the second embodiment and the obstacle detection device including the ultrasonic sensor 100 are common to the ultrasonic sensor 100 and the obstacle detection device including the ultrasonic sensor 100 illustrated in the first embodiment. However, since there are many cases, detailed descriptions of common parts will be omitted, and different parts will be described mainly. In addition, the same code | symbol shall be provided to the element same as the element shown in 1st Embodiment.

In the first embodiment, an example in which the same medium (air) as that outside the vehicle is arranged in each tube portion 132 of the waveguide 130 has been described. On the other hand, in the present embodiment, as shown in FIGS. 3A and 3B, the inside of the pipe portion 132 is a medium (air) outside the vehicle and the bottom surface portion 121 of the casing 120 (aluminum as an example). It is characterized by being filled with an acoustic matching member 140 having an acoustic impedance between and. The acoustic impedance (kg / m ² s) is a value specific to the medium and is determined by ρc (ρ: density, c: sound velocity). The acoustic impedance of air is 4.1 × 10 ² (15 ° C.), and the acoustic impedance of aluminum is 1.4 × 10 ⁷ .

  Ultrasonic waves have a characteristic that the amount of reflection increases as the difference in acoustic impedance increases between members having different acoustic impedances. As described above, the acoustic impedance of the acoustic matching member 140 is a value between the atmosphere outside the vehicle and the acoustic impedance of the bottom surface portion 121 of the housing 120. Therefore, according to the ultrasonic sensor 100 and the obstacle detection device including the ultrasonic sensor 100 according to the present embodiment, between the outside of the vehicle and the acoustic matching member 140, and further, the bottom surface portion of the acoustic matching member 140 and the casing 120 The acoustic reflection member 140 can reduce the amount of ultrasonic reflection between the acoustic vehicle 121 and the ultrasonic transmission amount between the outside of the vehicle and the bottom surface part 121 (piezoelectric vibrator 110) of the housing 120. It can be increased over a configuration that is not.

  Further, as shown in FIGS. 1A and 1B, the acoustic matching member 140 is disposed in the respective tube portions 132 without a gap so as to close the opening 133. Accordingly, it is possible to prevent foreign matters such as stepping stones, water, and wax during car washing from entering the pipe portion 132. That is, it is possible to prevent the detection accuracy from being lowered due to the foreign matter. In addition, it is possible to reliably prevent the collision of foreign matter (particularly stepping stone) with the vibration surface (outer surface 123) of the housing 120, so that the bottom surface 121 of the housing 120 and the piezoelectric vibrator 110 are prevented from being damaged (ultrasonic waves). The impact resistance of the sensor 100 can be improved. In the present embodiment, a portion of the acoustic matching member 140 that is exposed to the outside through the through hole 13 of the bumper 10 is flush with the opening surface of the opening end 133. Therefore, it has a preferable configuration from the viewpoint of appearance.

  The acoustic matching member 140 can be used as long as it satisfies the above-mentioned conditions. Preferably, the material (aluminum) that constitutes the medium (air) outside the vehicle and the bottom surface portion 121 of the housing 120 is used. Of these, the one having a value close to the medium outside the vehicle may be adopted. As such an acoustic matching member 140, for example, a member having a reduced density, such as a member configured in a porous shape (porous shape) or a member including a large number of beads (including air) can be used. . When such an acoustic matching member 140 is employed, the space between the medium (air) outside the vehicle and the acoustic matching member 140 is larger than when a material close to the material constituting the bottom surface portion 121 of the housing 120 is employed. The amount of ultrasonic reflection at can be reduced. Further, the outer surface 123 as the vibration surface can be vibrated by receiving the vibration and / or the reflected wave of the piezoelectric vibrator 110.

(Third embodiment)
Next, a third embodiment of the present invention will be described with reference to FIG. 4A and 4B are diagrams illustrating a schematic configuration of an ultrasonic sensor 100 according to the third embodiment, in which FIG. 4A is a plan view and FIG. 4B is a cross-sectional view taken along line CC in FIG. 4 (a) and 4 (b) correspond to FIGS. 1 (a) and 1 (b), respectively.

  Since the ultrasonic sensor 100 according to the third embodiment is common in common with the ultrasonic sensor 100 shown in the first embodiment, the detailed description of the common parts will be omitted below, and different parts will be described mainly. . In addition, the same code | symbol shall be provided to the element same as the element shown in 1st Embodiment.

  In the first embodiment, an example in which a plurality of tube portions 132 are provided for one base member 131 and integrated as one waveguide 130 has been described. In contrast, in the present embodiment, as shown in FIGS. 4A and 4B, the tube portion 132 is separated into a plurality of parts corresponding to the piezoelectric vibrator 110, and one waveguide 130 (base material) is formed. 131) is characterized in that it includes a single pipe portion 132. More specifically, the base material 131 shown in the first embodiment is configured to be divided in the direction along the horizontal direction and the direction along the vertical direction with respect to the road surface, and includes one pipe portion 132. It has four waveguides 130 (base material 131). And the unnecessary vibration reduction member 150 in which acoustic impedance differs from the base material 131 is arrange | positioned between each division surface, and it accommodates and hold | maintains in the same case 151. FIG. The unnecessary vibration reducing member 150 is for reducing unnecessary vibration transmitted between the waveguides 130 (base material 131), and is made of, for example, silicon rubber, polyurethane, or the like, similar to the vibration absorbing member 124 described above. ing. In addition, in the state where each waveguide 130 is held in the case 151, the configuration other than the above is the same as that of the ultrasonic sensor 100 shown in the first embodiment.

  As described above, according to the ultrasonic sensor 100 and the obstacle detection apparatus including the ultrasonic sensor 100 according to the present embodiment, since the base material 131 is divided for each one pipe portion 132, the first embodiment is used. Compared to the illustrated configuration, unnecessary vibration transmitted between the waveguides 130 (tube portions 132) can be reduced. Furthermore, in this embodiment, the unnecessary vibration reducing member 150 is disposed between the divided surfaces of the base material 131, so that unnecessary vibration can be more effectively reduced.

  The configuration shown in the present embodiment can be combined not only with the configuration shown in the first embodiment but also with the configuration shown in the second embodiment.

(Fourth embodiment)
Next, a fourth embodiment of the present invention will be described with reference to FIG. 5A and 5B are diagrams illustrating a schematic configuration of an ultrasonic sensor 100 according to the fourth embodiment. FIG. 5A is a plan view, and FIG. 5B is a cross-sectional view taken along the line DD in FIG. 5A and 5B correspond to FIGS. 1A and 1B, respectively.

  The ultrasonic sensor 100 according to the fourth embodiment and the obstacle detection device including the ultrasonic sensor 100 are common to the ultrasonic sensor 100 and the obstacle detection device including the ultrasonic sensor 100 illustrated in the first embodiment. However, since there are many cases, detailed descriptions of common parts will be omitted, and different parts will be described mainly. In addition, the same code | symbol shall be provided to the element same as the element shown in 1st Embodiment.

  In the first embodiment, an example in which the opening area of the opening end 133 on the bumper 10 side is smaller than the area of the outer surface 123 that is the vibration surface and smaller than the opening area of the opening end 136 on the vibration surface side is shown. . That is, in the pipe portion 132, an example in which the pipe diameter (cross-sectional area) increases from the opening end 133 toward the opening end 136 (vibration surface) is shown. In such a configuration, since the tube diameter (cross-sectional area) of the tube portion 132 is larger with respect to the traveling direction of the reflected wave (received wave), interference in the tube portion 132 is caused with respect to the reflected wave. Can be reduced. However, since the tube diameter (cross-sectional area) of the tube portion 132 is small with respect to the traveling direction of the transmission wave, there is a concern about interference in the tube portion 132 for transmission.

  On the other hand, in this embodiment, as shown in FIGS. 5A and 5B, for example, a pipe section 132 having a circular cross section is used, and the opening area of the opening end 133 on the bumper 10 side is set as follows. It is smaller than the area of the outer surface 123 that is the vibration surface and larger than the opening area of the opening end 136 on the vibration surface side. In other words, the tube diameter (cross-sectional area) is reduced from the opening end 133 toward the opening end 136 (vibration surface). The opening end 136 is arranged so as to overlap the outer surface 123 when viewed from the outside of the vehicle, and the vibration of the bottom surface portion 121 as a diaphragm is not suppressed between the outer surface 123 and the opening end 136. In addition, a slight gap is provided so that ultrasonic waves do not leak. In FIG. 5A, the outer surface 123 shown in the first embodiment is not shown, and the open end 136 is shown.

  As described above, according to the ultrasonic sensor 100 and the obstacle detection device including the ultrasonic sensor 100 according to the present embodiment, it is possible to efficiently transmit the transmission wave from the outer surface 123 to the opening end 133 in particular.

  In the present embodiment, as in the first embodiment, all the piezoelectric vibrators 110 are used for both transmission and reception. Therefore, since the tube diameter (cross-sectional area) of the tube portion 132 is small with respect to the traveling direction of the reflected wave, there is a concern about interference in the tube portion 132 for reception. Therefore, for example, as shown in FIG. 6, the piezoelectric vibrator 110 is divided into a piezoelectric vibrator 110a dedicated to transmission and a piezoelectric vibrator 110b dedicated to reception, and the tube portion 132 is also suitable for transmission as shown in this embodiment. The pipe part 132a (opening ends 133a and 136a) and the pipe part 132b (opening parts 133b and 136b) suitable for reception as shown in the first embodiment may be used. With such a configuration, transmission efficiency of ultrasonic waves can be improved for both transmission and reception. FIG. 6 is a cross-sectional view showing a modification.

  Moreover, in this embodiment, although the cross-sectional shape of the pipe part 132 was shown circular, the cross-sectional shape of the pipe part 132 is not limited to the said example. For example, a rectangular shape or a polygonal shape other than a rectangle may be used. However, since the interference of ultrasonic waves can be reduced as it approaches the circle, it is preferable to use a circular cross section as shown in this embodiment.

  Note that the configuration (including modifications) shown in the present embodiment can be combined not only with the configuration shown in the first embodiment, but also with the configuration shown in the second embodiment or the third embodiment.

(Fifth embodiment)
Next, a fifth embodiment of the present invention will be described with reference to FIG. 7A and 7B are diagrams showing a schematic configuration of an ultrasonic sensor 100 according to the fifth embodiment. FIG. 7A is a plan view, and FIG. 7B is a cross-sectional view taken along line EE in FIG. 7A and 7B correspond to FIGS. 1A and 1B, respectively.

  The ultrasonic sensor 100 according to the fifth embodiment and the obstacle detection device including the ultrasonic sensor 100 include the ultrasonic sensor 100 and the obstacle including the ultrasonic sensor 100 illustrated in the first embodiment and the fourth embodiment. Since there are many places in common with the detection apparatus, detailed description of the common parts will be omitted below, and different parts will be described mainly. In addition, the same code | symbol shall be provided to the element same as the element shown in 1st Embodiment.

  In the first embodiment, an example in which the tube diameter (cross-sectional area) of the tube portion 132 is increased from the opening end 133 toward the opening end 136 (vibration surface) is shown. Moreover, in 4th Embodiment, the example which makes the pipe diameter (cross-sectional area) of the pipe part 132 small toward the opening end 136 (vibration surface) from the opening end 133 was shown. On the other hand, in this embodiment, as shown in FIGS. 7A and 7B, for example, the tube diameter is constant in the tube section 132 having a circular cross section. In other words, in the same pipe portion 132, the cross-sectional shape and the cross-sectional area are made constant between the opening end 133 on the bumper 10 side and the opening end 136 on the vibration surface side. Also in this embodiment, the opening end 136 is disposed so as to overlap the outer surface 123 when viewed from the outside of the vehicle, and the bottom surface portion 121 as a diaphragm is interposed between the outer surface 123 and the opening end 136. A slight gap is provided such that vibration is not suppressed and ultrasonic waves do not leak. In FIG. 7A, the outer surface 123 shown in the first embodiment is not shown, and the open end 136 is shown.

  As described above, according to the ultrasonic sensor 100 and the obstacle detection apparatus including the ultrasonic sensor 100 according to the present embodiment, the cross-sectional shape and the pipe diameter (cross-sectional area) are constant. The interference of waves or reflected waves can be reduced. That is, the transmitted wave or the reflected wave can be efficiently transmitted between the outer surface 123 and the open end 133.

  In the present embodiment, as in the first embodiment, all the piezoelectric vibrators 110 are used for transmission and reception, and the cross-sectional shape and the pipe diameter (cross-sectional area) are constant in all the pipe portions 132. However, the plurality of tube portions 132 may include at least one of the tube portion 132 shown in the first embodiment and the tube portion 132 shown in the fourth embodiment together with the tube portion 132 shown in the present embodiment. .

  Moreover, in this embodiment, although the cross-sectional shape of the pipe part 132 was shown circular, the cross-sectional shape of the pipe part 132 is not limited to the said example. For example, a rectangular shape or a polygonal shape other than a rectangle may be used. In any cross-sectional shape, the cross-sectional area may be constant between the opening end 133 on the bumper 10 side and the opening end 136 on the vibration surface side. However, the closer to the circle, the more the interference of the transmitted wave or reflected wave can be reduced. Therefore, a circular cross section is preferable as shown in the present embodiment.

  Further, the configuration shown in the present embodiment can be combined with the configuration shown in the second embodiment or the configuration shown in the third embodiment.

  The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention.

  In this embodiment, the example in which the ultrasonic sensor 100 is attached to the bumper 10 of the vehicle as a moving body is shown. However, the moving body is not limited to the vehicle, and the attached portion is not limited to the bumper 10. Even a vehicle can be attached to a body, for example.

  In the present embodiment, an example in which the opening shape of the opening end 133 exposed to the outer surface 12 side of the bumper 10 is circular in the plurality of pipe portions 132 is shown. However, the opening shape of each opening end 133 is, for example, as shown in FIG. 8, in the biaxial direction perpendicular to the opening surface (in FIG. 8, as in FIG. 1, the horizontal direction and the vertical direction with respect to the road surface) It is good also as a shape from which length differs. According to this, it is possible to make the directivities different (provide partial directivity) in the biaxial directions. According to the configuration shown in FIG. 8, since the opening width is narrow in the horizontal direction and wide in the vertical direction, the directivity can be wide in the horizontal direction and narrow in the vertical direction. FIG. 8 is a plan view showing a modified example, and corresponds to FIG.

  In the present embodiment, an example in which the opening shapes and sizes of the opening ends 133 exposed on the outer surface 12 side of the bumper 10 are all set equal in the plurality of pipe portions 132 has been described. However, for example, as shown in FIG. 9, a plurality of opening shapes (at least one opening end 133 is different from other opening ends 133) may be set. Since the directivity of the ultrasonic sensor 100 is determined by the shape and size of the opening end 133, the directivity can be switched according to the opening shape. In the configuration shown in FIG. 9, two of the four opening ends 133 are narrow in the horizontal direction and wide in the vertical direction, and the other two are wide in the horizontal direction and vertically. It is narrow. FIG. 9 is a plan view showing a modification, and corresponds to FIG.

  In this embodiment, in order to detect the direction of the obstacle in a wide range in each of the vertical direction and the horizontal direction with respect to the road surface, the piezoelectric vibrator 110 having four reception functions is provided, and the corresponding opening end 133 is An example in which two substrates 131 are arranged in parallel in each direction with respect to the base material 131 exposed on the outer surface 12 side of the bumper 10 is shown. However, the number of piezoelectric vibrators 110 and the arrangement of the open ends 133 are not limited to the above example. It is sufficient that the piezoelectric vibrator 110 having at least two reception functions is included, and the obstacle detection device is provided with the opening end 133 in parallel so that the obstacle detection device calculates the direction of the obstacle based on the phase difference between these reception signals. For example, as shown in FIG. 10A, a configuration may be adopted in which two open ends 133 are juxtaposed in the horizontal direction with respect to the road surface, corresponding to the two piezoelectric vibrators 110 having a receiving function. Further, as shown in FIG. 10B, a configuration may be adopted in which triangular arrangement is provided corresponding to the three piezoelectric vibrators 110 having a receiving function with respect to FIG. In the case of the configuration shown in FIG. 10A, the direction of the obstacle can be detected in a wide range in the horizontal direction with respect to the road surface. In the case of the configuration shown in FIG. 10B, the direction of the obstacle can be detected in a wide range in the horizontal direction and the vertical direction with respect to the road surface, similarly to the configuration shown in the first embodiment. In addition, since the number of tube portions 132 corresponding to the piezoelectric vibrator 110 is smaller than the configuration shown in the first embodiment, the configuration can be simplified and the cost can be reduced. FIG. 10 is a plan view showing a modification of both (a) and (b), and corresponds to FIG. 1 (a).

  In the present embodiment, of the four pipe portions 132, two pipes in which the opening lower position of the opening end 133 on the bumper 10 side is located higher in the direction of gravity than the lower position of the opening end 136 on the vibration surface side. The example including the part 132 was shown. That is, an example in which the pipe portion 132 is inclined downward from the opening end 133 toward the opening end 136 (outer surface 123) is shown. In the pipe part 132 having such a configuration, if the acoustic matching member 140 shown in the second embodiment is not filled in the pipe part 132, there is a possibility that foreign matters such as stones, water, and mud may enter. That is, there is a possibility that the detection accuracy may be reduced due to the foreign matter. Accordingly, as shown in FIG. 11, for example, as shown in FIG. 11, the lower opening position of the opening end 133 on the bumper 10 side is positioned lower in the gravity direction than the lower position of the opening end 136 on the vibration surface side. It is preferable to include only the tube portion 132. That is, it is preferable to configure the tube portion 132 so as to incline upward from the opening end 133 toward the opening end 136 (the outer surface 123). With such a configuration, intrusion of foreign matter into the tube portion 132 can be suppressed as compared with a configuration inclined downward. In addition, the structure shown in FIG. 11 is applied to each pipe part 132 in the structure by which the two opening ends 133 were arranged in parallel with the road surface, as shown to Fig.10 (a). FIG. 11 is a cross-sectional view showing a modification.

  In the present embodiment, the base 131 is provided with a fixing groove 134 communicating with the tube portion 132, and the outer surface which is a vibration surface in a state where the casing 120 including the piezoelectric vibrator 110 is fixed to the fixing groove 134. An example is shown in which at least a part of 123 is exposed from the open end 136 of the tube portion 132 and is configured to be able to transmit or receive ultrasonic waves via the tube portion 132. However, for example, as shown in FIG. 12, a holding member 160 to which the casing 120 including the piezoelectric vibrator 110 is fixed is provided separately from the base material 131, and the holding member 160 is fixed to the base material 131 through an adhesive tape 170. In this state, at least a part of the outer surface 123 exposed from the holding member 160 may be exposed from the open end 136 of the tube portion 132. In the configuration shown in FIG. 12, by giving the adhesive tape 170 a function as a spacer, the vibration of the bottom surface portion 121 as a diaphragm is not suppressed between the outer surface 123 and the open end 136, and A slight gap is secured so that sound waves do not leak. FIG. 12 is a cross-sectional view showing a modification. Although FIG. 12 shows an example in which the holding member 160 is fixed to the base material 131 with the adhesive tape 170, the fixing method is not limited to the above example.

  In the present embodiment, an example is shown in which the distance d between the adjacent open ends 133 is equal in the horizontal direction dx with respect to the road surface and in the vertical direction dy with respect to the road surface. However, the distance d between the open ends 133 only needs to be narrower than the distance D (Dx, Dy) between the corresponding vibration surfaces (outer surfaces 123). Therefore, different intervals may be set in the horizontal direction dx and the vertical direction dy. In FIG. 1A, a distance between two opening ends 133 that are adjacent in the diagonal direction (in a diagonal position) may be set as a distance d.

It is a figure which shows schematic structure of the ultrasonic sensor which concerns on 1st Embodiment, (a) is a top view, (b) is sectional drawing which follows the AA line of (a). FIG. 2 is an enlarged cross-sectional view around a housing in FIG. It is a figure which shows schematic structure of the ultrasonic sensor which concerns on 2nd Embodiment, (a) is a top view, (b) is sectional drawing which follows the BB line of (a). It is a figure which shows schematic structure of the ultrasonic sensor which concerns on 3rd Embodiment, (a) is a top view, (b) is sectional drawing which follows the CC line of (a). It is a figure which shows schematic structure of the ultrasonic sensor which concerns on 4th Embodiment, (a) is a top view, (b) is sectional drawing which follows the DD line | wire of (a). It is sectional drawing which shows a modification. It is a figure which shows schematic structure of the ultrasonic sensor which concerns on 5th Embodiment, (a) is a top view, (b) is sectional drawing which follows the EE line of (a). It is a top view which shows a modification. It is a top view which shows a modification. (A), (b) is a top view which shows a modification. It is sectional drawing which shows a modification. It is sectional drawing which shows a modification.

Explanation of symbols

10 ... Bumper (attached part)
DESCRIPTION OF SYMBOLS 100 ... Ultrasonic sensor 110 ... Piezoelectric vibrator 120 ... Housing 121 ... Bottom part 123 ... Outer surface (vibration surface)
131 ... Base material 132 ... Tube part (waveguide)
133, 136 ... Open end

Claims (17)

At least one transmission piezoelectric vibrator that transmits ultrasonic waves as a transmission wave to the outside of the moving body;
A plurality of receiving piezoelectric vibrators for receiving a reflected wave from the obstacle of the transmitted wave and outputting a received signal corresponding to the intensity of the reflected wave;
Housings each of the piezoelectric vibrators, wherein the piezoelectric vibrator is contacted and fixed to the inner surface of the bottom surface portion, and the outer surface of the bottom surface portion is a vibration surface;
One open end is exposed to the outside through a through-hole formed in the attached portion of the moving body, and an ultrasonic wave is generated between the outside of the moving body and the vibration surface disposed inside the moving body. And a waveguide for guiding
The waveguide is provided in a plurality corresponding to at least the receiving piezoelectric vibrator, the opening area of the opening end is smaller than the area of the vibration surface, and the opening interval of the adjacent opening ends is adjacent. The distance between the vibration surfaces is narrower, and the reflected waves are set to lengths that are transmitted to the vibration surface while maintaining the mutual phase difference in the attached portion ,
In each of the plurality of waveguides, each opening end has a shape in which the opening shape has different lengths in the x direction and the y direction, which are biaxial directions perpendicular to the opening surface, and the opening shape of the opening end is The opening end has an opening end whose opening width in the y direction is narrower than the x direction and an opening end whose opening width in the x direction is narrower than the y direction. Ultrasonic sensor to do. An opening end whose opening width in the y direction is narrower than the x direction and an opening end whose opening width in the x direction is narrower than the y direction are arranged in the x direction and the y direction, respectively. The ultrasonic sensor according to claim 1. The ultrasonic sensor according to claim 1, wherein a plurality of tube portions are formed on the same base material made of a resin material, and all the waveguides are integrated. The ultrasonic sensor according to claim 1 , wherein the waveguide is separated into a plurality corresponding to the receiving piezoelectric vibrator. 5. The ultrasonic sensor according to claim 4 , wherein an unnecessary vibration reducing member having an acoustic impedance different from that of a material constituting the waveguide is disposed between the plurality of separated waveguides. In at least one of the waveguide, the opening area of the opening end of the attachment portion side, to claims 1-5 any one, characterized in that less than the opening area of the open end of the vibrating surface The described ultrasonic sensor. In at least one of the waveguide, the opening area of the opening end of the attachment portion side, to claims 1-6 any one of being greater than the opening area of the open end of the vibrating surface The described ultrasonic sensor. The cross-sectional shape and the cross-sectional area between the opening end on the attached portion side and the opening end on the vibration surface side are fixed in at least one of the waveguides, respectively . 7 ultrasonic sensor according to any one. The ultrasonic sensor according to claim 1 , wherein at least one of the plurality of piezoelectric vibrators serves both for transmission and reception. The ultrasonic sensor according to claim 1 , wherein the plurality of waveguides are all equal in length. The ultrasonic sensor according to claim 1 , wherein the opening end is flush with an external side of the attached portion. The ultrasonic sensor according to any one of claims 1 to 11 , wherein an opening interval between adjacent opening ends is set to a half wavelength or less with respect to a wavelength of the ultrasonic wave. The piezoelectric vibrator has two or more for transmission,
The ultrasonic sensor according to claim 1 , wherein the ultrasonic waves are transmitted simultaneously from a plurality of the transmitting piezoelectric vibrators. The opening lower position of the open end of the attachment portion side, than the lower position of the opening end of the vibrating surface, according to claim 1 to 13 any one, characterized in that there is a downward in the gravitational direction The ultrasonic sensor as described in. The waveguide according to claim 1 to 13 in which the tubular interior, characterized in that it is filled with the acoustic matching member having an acoustic impedance between the bottom portion of the outside atmosphere of the moving body and said casing The ultrasonic sensor according to any one of claims. The ultrasonic sensor according to claim 1, wherein the moving body is a vehicle, and the attached portion is a bumper or a body. The ultrasonic sensor according to any one of claims 1 to 16 , comprising:
An obstacle detection apparatus that detects an orientation of the obstacle based on a phase difference between reception signals of the plurality of reception piezoelectric vibrators.

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