Sensor mounting structure

Abstract

The invention provides a sensor mounting structure. It is possible to suppress deterioration in appearance of an outer plate member provided with an ultrasonic sensor. A sensor mounting structure is provided with: an outer plate member provided with a through-hole 7; an ultrasonic sensor (10) disposed on the inside of the through-hole; and a sealing member 30 that covers the through-hole and is disposed so as to be spaced apart from the ultrasonic sensor. The sensor mounting structure is configured such that ultrasonic waves transmitted from the ultrasonic sensor pass through the through-hole and propagate to the outside via the sealing member, and reflected waves reflected from the outside pass through the sealing member and are received by the ultrasonic sensor through the through-hole.

Description

Technical Field

[0001] The present disclosure relates to a sensor mounting structure. Background Art

[0002] Conventionally, it has been known to provide an ultrasonic sensor as a gap sonar in an outer panel member such as a bumper of a vehicle (for example, Patent Document 1). In particular, the ultrasonic sensor described in Patent Document 1 is disposed in an assembly hole formed in a bumper such that its top surface protrudes outward from the assembly hole formed in the bumper.

[0003] Prior Art Documents

[0004] Patent Documents

[0005] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2020-161888 Summary of the Invention

[0006] Problems to be Solved by the Invention

[0007] When an ultrasonic sensor is disposed in a through hole formed in an outer panel member such as a bumper, a height difference or a slanted gap may be generated between the surface of the outer panel member around the ultrasonic sensor and the outer surface of the ultrasonic sensor, or the surface of the outer panel member and the outer surface of the ultrasonic sensor may be inclined relative to each other. When such a height difference, a slanted gap, or an inclination is formed, the appearance of the outer panel member deteriorates.

[0008] In view of the above problems, an object of the present disclosure is to provide a sensor mounting structure capable of suppressing deterioration of the appearance of an outer panel member provided with an ultrasonic sensor.

[0009] Means for Solving the Problems

[0010] The gist of the present disclosure is as follows.

[0011] (1) A sensor mounting structure includes:

[0012] an outer panel member provided with a through hole;

[0013] an ultrasonic sensor disposed inside the through hole; and

[0014] a sealing member covering the through hole and disposed so as to be separated from the ultrasonic sensor,

[0015] The sensor mounting structure is configured such that ultrasonic waves transmitted from the ultrasonic sensor pass through the through hole and propagate to the outside via the sealing member, and a reflected wave reflected outside (reflected outside) is received by the ultrasonic sensor via the sealing member and through the through hole.

[0016] (2) The sensor mounting structure according to (1) above, wherein the sealing member is configured such that the amplitude of the ultrasonic wave transmitted from the ultrasonic sensor and transmitted to the outside through the sealing member is greater than the amplitude of the ultrasonic wave transmitted from the ultrasonic sensor and transmitted to the outside through the outer plate member in the case where the outer plate member is assumed to be provided in place of the sealing member (the outer plate member is provided in a manner to replace the sealing member).

[0017] (3) The sensor mounting structure according to (1) or (2) above, wherein the sealing member is configured to resonate due to the ultrasonic wave transmitted by the ultrasonic sensor.

[0018] (4) The sensor mounting structure according to any one of (1) to (3) above, wherein the sealing member is configured to have a natural frequency with a deviation of within 5% from the natural frequency (natural vibration frequency) of the member that transmits ultrasonic waves in the ultrasonic sensor.

[0019] (5) The sensor mounting structure according to any one of (1) to (4) above, wherein the thickness of the sealing member is thinner than the thickness of the outer plate member.

[0020] (6) The sensor mounting structure according to any one of (1) to (5) above,

[0021] The outer plate member has a plurality of through holes,

[0022] One ultrasonic sensor and one sealing member are arranged for each through hole,

[0023] The sealing member is configured to have at least partially different thicknesses.

[0024] (7) The sensor mounting structure according to any one of (1) to (6) above, wherein the sealing member is formed of the same material as the member that transmits ultrasonic waves in the ultrasonic sensor.

[0025] (8) The sensor mounting structure according to any one of (1) to (7) above,

[0026] The outer plate member has a coating film on its outer surface side,

[0027] The sealing member has a coating film formed of the same material as the coating film of the outer plate member on its outer surface side.

[0028] (9) The sensor mounting structure according to any one of (1) to (8) above,

[0029] The sealing member and the ultrasonic sensor are separated by a non-conductive separator disposed between the sealing member and the ultrasonic sensor.

[0030] (10) The sensor mounting structure according to any one of the above (1) to (9),

[0031] The sensor mounting structure further includes a processing unit electrically connected to the ultrasonic sensor.

[0032] The processing unit calculates the speed of an object in the surroundings based on a value obtained by multiplying the frequency of the reflected wave detected by the ultrasonic sensor by a predetermined coefficient.

[0033] The coefficient varies based on at least one of the distance and the angle between the ultrasonic sensor and the sealing member.

[0034] Effects of the Invention

[0035] According to the present disclosure, it is possible to suppress deterioration of the appearance of the outer panel member provided with the ultrasonic sensor. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 are a front view and a rear view of a vehicle including a sensor mounting structure according to one embodiment.

[0037] Figure 2 is a sectional view showing the configuration around the rear bumper as viewed along line A-A Figure 1 of.

[0038] Figure 3 is a schematic sectional view of an ultrasonic microphone.

[0039] Figure 4 is a sectional view showing the configuration around the rear bumper as viewed along line A-A and line B-B Figure 1 of.

[0040] Figure 5 is a block diagram schematically showing the configuration of electronic components of a vehicle.

[0041] Figure 6 is a sectional view similar to that showing the configuration around the rear bumper according to one modification example, Figure 2 of.

[0042] Figure 7 is a schematic sectional view of an ultrasonic microphone according to one modification example.

[0043] REFERENCE SIGNS LIST

[0044] 1: Vehicle;

[0045] 4: Rear bumper;

[0046] 10: Ultrasonic sensor;

[0047] 20: Mounting member;

[0048] 30: Sealing member;

[0049] 31: Partition member;

[0050] 54: ECU. Detailed implementation mode

[0051] Hereinafter, the implementation mode will be described in detail with reference to the drawings. In addition, in the following description, the same reference numerals are assigned to the same components.

[0052] <Configuration of vehicle>

[0053] First, with reference to Figure 1 , the vehicle 1 having the sensor mounting structure according to one embodiment will be briefly described. Figure 1 are the front view and the rear view of the vehicle 1 having the sensor mounting structure according to one embodiment. In particular, the front view of the vehicle 1 is shown by Figure 1 (A), and the rear view of the vehicle 1 is shown by Figure 1 (B).

[0054] In the present embodiment, the vehicle 1 is a four-wheel vehicle and has a box-shaped outer shape. As Figure 1 shown, the vehicle 1 includes a body panel 2, a front bumper 3, and a rear bumper 4 as components constituting its outer panel. Therefore, the body panel 2, the front bumper 3, and the rear bumper 4 are an example of the outer panel members constituting the outer panel of the vehicle 1. As Figure 1 (A) shows, the front bumper 3 is provided at the front end of the vehicle 1, and as Figure 1 (B) shows, the rear bumper 4 is provided at the rear end of the vehicle 1. In addition, the vehicle 1 may be a vehicle other than a four-wheel vehicle such as a three-wheel vehicle.

[0055] In addition, in the present embodiment, in the front bumper 3 and the rear bumper 4, an ultrasonic sensor 10 (refer to Figure 2 ) is installed inside. The ultrasonic sensors 10 installed in the front bumper 3 and the rear bumper 4 detect objects existing in front of and behind the vehicle 1. In addition, the ultrasonic sensor 10 may be installed in an outer panel member other than the bumpers 3 and 4.

[0056] The ultrasonic sensor 10 is provided inside the bumpers 3 and 4 at the position indicated by the dashed line M in Figure 1 . In the present embodiment, a plurality of (in Figure 1In the example of (A), there are four ultrasonic sensors 10, and these ultrasonic sensors 10 are arranged separately from each other in the vehicle width direction. Similarly, in the present embodiment, a plurality of (in the example of Figure 1 (B), there are four) ultrasonic sensors 10 are provided on the rear bumper 4, and these ultrasonic sensors 10 are arranged separately from each other in the vehicle width direction.

[0057] <Configuration of sensor mounting structure>

[0058] Next, with reference to Figure 2 , the configuration of the sensor mounting structure around one ultrasonic sensor 10 will be described. Hereinafter, although the configuration of the sensor mounting structure around the ultrasonic sensor 10 in the rear bumper 4 will be described as an example, the front bumper 3 has the same configuration. Figure 2 is a cross-sectional view showing the configuration around the rear bumper 4 observed along the line A - A of Figure 1 .

[0059] As Figure 2 shown, the sensor mounting structure includes an ultrasonic sensor 10, a rear bumper 4 for arranging the ultrasonic sensor 10, a mounting member 20 for mounting the ultrasonic sensor 10 on the rear bumper 4, a sealing member 30 for sealing the through hole 7 of the rear bumper 4, and a separating member 31 for separating the ultrasonic sensor 10 from the sealing member 30.

[0060] <Configuration of bumper>

[0061] With reference to Figure 2 , the configuration of the rear bumper 4 around the ultrasonic sensor 10 will be described. In the present embodiment, the rear bumper 4 is formed of resin. However, the rear bumper 4 may also be formed of a material other than resin such as metal. As Figure 2 shown, the rear bumper 4 has an outer surface 5 facing the outside of the vehicle 1 and an inner surface 6 on the opposite side of the outer surface 5 (the surface facing the inside of the vehicle 1). In addition, the rear bumper 4 has a coating film of an arbitrary paint on the outer surface 5 side.

[0062] In addition, the rear bumper 4 has a through hole 7 provided so as to penetrate the rear bumper 4 and a recess 8 formed around the through hole 7 between the outer surface 5 and the inner surface 6. Since one ultrasonic sensor 10 is provided in each through hole 7, a plurality of (in the example of Figure 1 (B), there are four) through holes 7 are provided in the rear bumper 4. In addition, since the recess 8 is formed around each through hole 7, a plurality of (in the example of Figure 1 (B), there are four) recesses 8 are provided in the rear bumper 4.

[0063] In the present embodiment, the through hole 7 is formed in a circular shape. However, the through hole 7 may have any shape other than a circular shape such as a polygonal shape. Further, the recess 8 is a portion that is recessed from the outer surface 5 of the rear bumper 4 toward the inner surface 6 side. The recess 8 is formed in an annular shape larger than the through hole 7 and communicates with the through hole 7. Therefore, as Figure 2 shown, the rear bumper 4 is formed in a two-step shape around the through hole 7.

[0064] <Configuration of Ultrasonic Sensor>

[0065] The ultrasonic sensor 10 is configured to be able to transmit and receive ultrasonic waves. Specifically, in the present embodiment, the ultrasonic sensor 10 transmits ultrasonic waves to the outside along the pointing axis X. Further, in the present embodiment, the ultrasonic sensor 10 receives a reflected wave of the ultrasonic wave transmitted from the ultrasonic sensor 10 that is reflected by an object existing in the vicinity, and generates and outputs a detection signal corresponding to the reception result.

[0066] As Figure 2 shown, the ultrasonic sensor 10 includes a sensor housing 11 and an ultrasonic microphone 12.

[0067] The sensor housing 11 is a component that holds a substrate, electronic components, etc. in addition to the ultrasonic microphone 12. The sensor housing 11 has a main body portion 11a and a connector 11b. The main body portion 11a holds the ultrasonic microphone 12 and houses a substrate therein, and the substrate has circuits for performing amplification, reverberation adjustment, sensitivity adjustment, etc. The connector 11b is provided on the side portion of the main body portion 11a and is configured to be able to attach and detach a wire-side connector for connecting to an ECU 54 or the like described later.

[0068] The ultrasonic microphone 12 transmits ultrasonic waves and receives reflected waves of the ultrasonic waves. Figure 3 is a schematic cross-sectional view of the ultrasonic microphone 12. As Figure 3 shown, the ultrasonic microphone 12 has a housing 13, a piezoelectric element 14, a sound absorbing member 15, and terminals 16.

[0069] The housing 13 is a cylindrical member, for example, formed of a conductive material such as metal. The housing 13 is fixed to the sensor housing 11 so as to protrude from the sensor housing 11. Further, the axis of the housing 13 is located on the pointing axis X.

[0070] The piezoelectric element 14 is an element that deforms in shape when a voltage is applied (reverse piezoelectric effect) and generates a voltage when an external force is applied (piezoelectric effect). When a high-frequency alternating voltage is applied to the piezoelectric element 14, ultrasonic waves are generated. Additionally, when the piezoelectric element 14 is struck by ultrasonic waves, a high-frequency voltage corresponding to the ultrasonic waves is output. In particular, in the present embodiment, an alternating voltage such as "transmitting ultrasonic waves having the same frequency as the natural frequency of the piezoelectric element 14" is applied to the piezoelectric element 14. The piezoelectric element 14 is formed of a piezoelectric ceramic having this property.

[0071] In the present embodiment, the piezoelectric element 14 is fixed to the housing 13 on the front end side of the housing 13. In particular, the piezoelectric element 14 is arranged to be exposed to the outside of the housing 13 and thus to the outside of the ultrasonic sensor 10.

[0072] The sound-absorbing member 15 is arranged inside the housing 13 inside the piezoelectric element 14. The sound-absorbing member 15 is formed of a material capable of absorbing ultrasonic waves. The ultrasonic waves transmitted from the piezoelectric element 14 toward the inside of the housing 13 are absorbed by the sound-absorbing member 15. As a result, in the ultrasonic microphone 12, the ultrasonic waves transmitted from the piezoelectric element 14 are radiated unidirectionally along the pointing axis X.

[0073] The terminals 16 are formed of a conductive material such as metal and extend from inside the housing 13 to the outside of the housing 13. Two terminals 16 are provided in the ultrasonic microphone 12. One of the two terminals is electrically connected to the housing 13 through a lead wire, and the other is electrically connected to the piezoelectric element 14 through a lead wire.

[0074] In the ultrasonic microphone 12 configured as described above, when a high-frequency alternating voltage is applied between the terminals 16, the piezoelectric element 14 vibrates and ultrasonic waves are generated in the direction along the pointing axis X. Additionally, when ultrasonic waves strike the piezoelectric element 14 from the outside, a high-frequency voltage corresponding to the ultrasonic waves is output between the terminals 16.

[0075] Furthermore, in the ultrasonic sensor 10 according to the present embodiment, one piezoelectric element 14 is responsible for both the transmission and reception of ultrasonic waves. However, the ultrasonic sensor 10 may also be configured to have two piezoelectric elements, one for transmitting ultrasonic waves and the other for receiving ultrasonic waves and outputting a detection signal.

[0076] <Configuration of the mounting member>

[0077] The mounting member 20 is a member for mounting the ultrasonic sensor 10 to the rear bumper 4. In the present embodiment, as Figure 2 shown, one ultrasonic sensor 10 is arranged for each through-hole 7 for each mounting member 20. The mounting member 20 is formed of an arbitrary material such as resin and metal. As Figure 2As shown, the mounting member 20 is fixed to the inner surface 6 of the rear bumper 4 near the through-hole 7. The mounting member 20 is fixed to the rear bumper 4 by fastening connectors such as threaded members, adhesives, etc.

[0078] As Figure 2 shown, the mounting member 20 has a main body portion 21, an opening portion 22, and claws 23. The main body portion 21 is fixed to the inner surface 6 of the rear bumper 4 and holds the ultrasonic sensor 10. The opening portion 22 is formed at the center of the main body portion 21 facing the rear bumper 4. The opening portion 22 is formed such that when the ultrasonic sensor 10 is held by the main body portion 21, the front end of the ultrasonic microphone 12 of the ultrasonic sensor 10 is located within the opening portion 22. In addition, the mounting member 20 is mounted on the rear bumper 4 such that the opening portion 22 faces the through-hole 7 of the rear bumper 4. Further, a plurality of claws 23 are provided on the mounting member 20 for holding the ultrasonic sensor 10 to the main body portion 21.

[0079] In the present embodiment, the main body portion 21 holds the ultrasonic sensor 10 to the rear bumper 4 such that the pointing axis X of the ultrasonic sensor 10 passes through the center of the through-hole 7 of the rear bumper 4. In addition, the main body portion 21 holds the ultrasonic sensor 10 such that the front end (the portion where the piezoelectric element 14 is provided) of the ultrasonic microphone 12 of the ultrasonic sensor 10 faces the vicinity (the immediately adjacent inner side) of the through-hole 7. Therefore, the ultrasonic sensor 10 is disposed on the inner side of the through-hole 7 such that ultrasonic waves can be transmitted through the through-hole 7.

[0080] <Configuration of the sealing member and the partition member>

[0081] As Figure 2 shown, the sealing member 30 is configured to cover the through-hole 7 of the rear bumper 4, that is, to close the through-hole 7. Therefore, the sealing member 30 is disposed outside the front end of the ultrasonic microphone 12 of the ultrasonic sensor 10 facing each other near the through-hole 7. Thus, ultrasonic waves transmitted from the ultrasonic sensor 10 are propagated to the outside through the through-hole 7 via the sealing member 30. In addition, the reflected wave reflected outside is received by the ultrasonic sensor 10 via the sealing member 30 and through the through-hole 7.

[0082] One sealing member 30 is provided for each through-hole 7 of the rear bumper 4. The sealing member 30 is formed larger than the through-hole 7, thereby covering the entire through-hole 7. In particular, in the present embodiment, the sealing member 30 has the same outer shape as the recess 8, and thus is formed to be embedded in the recess 8 without a gap.

[0083] And, the sealing member 30 is fixed to the recess 8. In particular, in the present embodiment, the sealing member 30 is bonded to the bottom surface of the recess 8. In particular, in Figure 2In the example shown, the sealing member 30 is formed to have a thickness approximately the same as the depth of the recess 8. Therefore, the outer surface of the sealing member 30 is coplanar or substantially coplanar with the outer surface 5 of the rear bumper 4. Further, the sealing member 30 does not contact the ultrasonic sensor 10 and is configured to be separated from the ultrasonic sensor 10.

[0084] In addition, in the present embodiment, the sealing member 30 is formed of the same material as the material that transmits ultrasonic waves in the ultrasonic sensor 10, that is, the same material as the piezoelectric element 14. Further, the sealing member 30 is configured to have a natural frequency (natural vibration frequency) substantially the same as the natural frequency of the piezoelectric element 14 (i.e., the member that transmits ultrasonic waves) of the ultrasonic sensor 10 when mounted on the rear bumper 4. More specifically, the sealing member 30 is configured to have a natural frequency with a deviation of 5% or less from the natural frequency of the piezoelectric element 14 of the ultrasonic sensor 10 when mounted on the rear bumper 4.

[0085] Alternatively, the sealing member 30 is configured to resonate due to the ultrasonic waves transmitted from the ultrasonic sensor 10. Here, "the sealing member 30 resonates due to the ultrasonic waves transmitted from the ultrasonic sensor 10" means, for example, "the frequency of the ultrasonic waves transmitted from the ultrasonic sensor 10 (i.e., the natural frequency of the piezoelectric element 14) is within a range of frequencies that become 1 / √2 times the peak output in the frequency characteristic curve having the natural frequency of the sealing member 30 as the peak (hereinafter, referred to as 'a predetermined frequency band around the natural frequency of the sealing member 30')". That is, the sealing member 30 is configured such that, for example, the frequency of the ultrasonic waves transmitted from the ultrasonic sensor 10 is within the predetermined frequency band around the natural frequency of the sealing member 30.

[0086] The natural frequency of the sealing member 30 varies not only according to the material and thickness of the sealing member 30 but also according to the mounting method of the sealing member 30 to the rear bumper 4 and the shape of the rear bumper 4 around the sealing member 30. Therefore, sometimes even if the sealing members 30 of the same size and thickness are mounted on the rear bumper 4 so as to cover the through holes 7 of the same size, the natural frequencies of the sealing members 30 of the rear bumper 4 are different from each other. Therefore, when the sizes and thicknesses of all the sealing members 30 mounted on the rear bumper 4 are the same, for some of the sealing members 30, their natural frequencies will be different from the natural frequency of the piezoelectric element 14 of the ultrasonic sensor 10.

[0087] Therefore, in the present embodiment, the sealing member 30 is formed such that its thickness is different for each sealing member 30 or for every "several sealing members 30". Figure 4 is a cross-sectional view showing the configuration around the rear bumper 4 observed along Figure 1 lines A - A and B - B. In particular, respectively by Figure 4(A) shows a cross-sectional view observed along line A - A of Figure 1 and (B) shows a cross-sectional view observed along line B - B of Figure 4 (B) shows a cross-sectional view observed along line B - B of Figure 1 .

[0088] From Figure 4 (A) and Figure 4 (B), it can be seen that Figure 4 the thickness t of the sealing member 30 shown in (B) 2 is smaller than Figure 4 the thickness t of the sealing member 30 shown in (A). 1 Therefore, in the present embodiment, the sealing member 30 is configured to have at least partially different thicknesses. However, Figure 4 the sealing member 30 shown in (A) and Figure 4 the sealing member 30 shown in (B) are both configured to have a natural frequency substantially the same as that of the piezoelectric element 14 of the ultrasonic sensor 10, or to resonate due to the ultrasonic waves transmitted by the ultrasonic sensor 10. That is, in the present embodiment, even though the mounting method of the sealing member 30 to the rear bumper 4 and the shape of the rear bumper 4 around the sealing member 30 are different from each other, each sealing member 30 is configured to have a natural frequency substantially the same as that of the piezoelectric element 14 of the ultrasonic sensor 10, or to resonate due to the ultrasonic waves transmitted by the ultrasonic sensor 10.

[0089] In addition, in the present embodiment, the sealing member 30 has a coating film formed of the same material as the coating film of the rear bumper 4 on its outer surface side. In particular, in the present embodiment, after the sealing member 30 is installed in the recess 8 of the rear bumper 4 before painting, the rear bumper 4 and the sealing member 30 are painted together. As described above, in the present embodiment, the outer surface of the sealing member 30 is coplanar or substantially coplanar with the outer surface 5 of the rear bumper 4, so it is difficult to know that the sealing member 30 is provided in terms of appearance. By having the sealing member 30 have a coating film formed of the same material as the coating film of the rear bumper 4 and the outer surface of the sealing member 30 be coplanar or substantially coplanar with the outer surface 5 of the rear bumper 4 in this way, the deterioration of the aesthetics of the rear bumper 4 caused by the installation of the ultrasonic sensor 10 can be suppressed.

[0090] The separator 31 is disposed between the sealing member 30 and the ultrasonic sensor 10, particularly between the inner surface of the sealing member 30 and the outer surface of the ultrasonic microphone 12. As a result, the sealing member 30 and the ultrasonic sensor 10 are separated by the separator 31. The separator 31 is formed in an annular shape and faces the outer surface of the housing 13 of the ultrasonic microphone 12. The separator 31 is in contact with at least one of the inner surface of the sealing member 30 and the outer surface of the ultrasonic microphone 12. As a result, the situation where the piezoelectric element 14 of the ultrasonic microphone 12 comes into contact with the sealing member 30 formed of the same material as the piezoelectric element 14 can be suppressed.

[0091] In addition, the separator 31 is formed of a non-conductive material, such as resin. Therefore, even if the separator 31 comes into contact with both the sealing member 30 and the ultrasonic sensor 10, the situation where current flows between the sealing member 30 and the piezoelectric element 14 of the ultrasonic sensor 10 can be suppressed. Therefore, the situation where the piezoelectric element 14 is short-circuited or a part of the current that should flow through the piezoelectric element 14 flows to the sealing member 30 can be suppressed.

[0092] <Electronic components>

[0093] Next, with reference to Figure 5 , the electronic components of the vehicle 1 will be described. Figure 5 is a block diagram schematically showing the configuration of the electronic components of the vehicle 1. As Figure 5 shown, in the present embodiment, in addition to the ultrasonic sensor 10, the vehicle 1 further includes an outside camera 51, a speaker 52, a display 53, and an electronic control unit (hereinafter referred to as "ECU") 54. However, the vehicle 1 does not necessarily have all of the above devices. For example, the vehicle 1 may not have the speaker 52.

[0094] The ultrasonic sensor 10, the outside camera 51, the speaker 52, the display 53, and the ECU 54 are electrically connected via an in-vehicle network 55 in a communicable manner. The in-vehicle network 55 is a network that complies with standards such as CAN (Controller Area Network).

[0095] The outside camera 51 is a device that captures the surroundings of the vehicle 1. The outside camera 51 outputs the captured image to the ECU 54 via the in-vehicle network 55 at a predetermined cycle. The speaker 52 is a device that outputs sound, and the display 53 is a device that displays images. The speaker 52 and the display 53 output sound and display images based on signals received from the ECU 54 via the in-vehicle network 55.

[0096] The ECU 54 functions as a processing unit that processes the received signals. In the present embodiment, the ECU 54 calculates the distance to an object around the vehicle 1 and the relative speed of the object based on the output of the ultrasonic sensor 10. In addition, when it is determined based on the output of the ultrasonic sensor 10 that the distance to an object around the vehicle 1 is close or becoming close, the ECU 54 outputs a sound signal to the speaker 52 to emit a warning sound, and outputs an image signal to the display 53 to display an image indicating the warning. At this time, the ECU 54 may also output an image signal to the display 53 to superimpose and display a warning on the image captured by the outside vehicle camera 51.

[0097] As Figure 5 shown, the ECU 54 includes a communication interface 541, a memory 542, and a processor 543. The communication interface 541 is a circuit for connecting the ECU 54 to other electronic components of the vehicle 1. The memory 542 is a storage medium for storing data, such as a computer program executed by the processor 543 and various data used by the executing computer program. The processor 543 performs various processes according to the computer program stored in the memory 542 based on the signals received from the ultrasonic sensor 10 and the outside vehicle camera 51.

[0098] In the present embodiment, the processor 543 calculates the distance to an object around the vehicle 1, particularly to an object located in the X direction of the pointing axis of each ultrasonic sensor 10, and the speed of the object based on the output of the ultrasonic sensor 10. In particular, the processor 543 calculates the distance to the object based on the delay of the ultrasonic wave (reflected wave reflected by the surrounding object) received by the ultrasonic sensor 10 relative to the ultrasonic wave transmitted by the ultrasonic sensor 10. Specifically, the greater the delay of the reflected wave received by the ultrasonic sensor 10 relative to the ultrasonic wave transmitted by the ultrasonic sensor 10, the farther the processor 543 calculates the distance to the object.

[0099] In addition, the processor 543 calculates the speed of surrounding objects based on the frequency of the ultrasonic waves (reflected waves) received by the ultrasonic sensor 10. Specifically, when the frequency of the reflected wave received by the ultrasonic sensor 10 is the same as the frequency of the ultrasonic wave transmitted by the ultrasonic sensor 10, the processor 543 calculates the relative speed of the object with respect to the vehicle 1 (i.e., with respect to the ultrasonic sensor 10) to be approximately 0. In addition, when the frequency of the reflected wave received by the ultrasonic sensor 10 is higher than the frequency of the ultrasonic wave transmitted by the ultrasonic sensor 10, the processor 543 calculates the relative speed of the object regarding the object approaching the vehicle 1. In particular, the processor 543 calculates the relative speed of the object assuming that "the higher the frequency of the reflected wave received by the ultrasonic sensor 10, the faster the relative speed of the object approaching the vehicle 1". On the other hand, when the frequency of the reflected wave received by the ultrasonic sensor 10 is lower than the frequency of the ultrasonic wave transmitted by the ultrasonic sensor 10, the processor 543 calculates the relative speed of the object regarding the object moving away from the vehicle 1. In particular, the processor 543 calculates the relative speed of the object assuming that "the lower the frequency of the reflected wave received by the ultrasonic sensor 10, the faster the relative speed of the object moving away from the vehicle 1".

[0100] In the present embodiment, a plurality of ultrasonic sensors 10 are arranged on the rear bumper 4. And for each arrangement position among the respective arrangement positions, or for each "plurality of arrangement positions", the shape of the rear bumper 4 around the installation position is different, and furthermore, the angle of the optimal pointing axis X with respect to the surface of the rear bumper 4 around the installation position is also different. As a result, for each sealing member 30 among the respective sealing members 30, or for each "several sealing members 30", the distance ΔL between the inner surface of the sealing member 30 and the front end of the ultrasonic microphone 12 of the corresponding ultrasonic sensor 10 is different (for example, in Figure 4 (A) and Figure 4 (B), the distances ΔL are different from each other). In addition, for each sealing member 30 among the respective sealing members 30, or for each "several sealing members 30", the angle Δα between the inner surface of the sealing member 30 and the front end face of the ultrasonic microphone 12 of the corresponding ultrasonic sensor 10 is different (for example, in Figure 4 (A) and Figure 4 (B), the angles Δα are different from each other).

[0101] Moreover, the frequency of the ultrasonic wave transmitted from the ultrasonic sensor 10 changes when passing through the sealing member 30. At this time, the degree of frequency change varies according to the distance ΔL between the inner surface of the sealing member 30 and the front end of the ultrasonic microphone 12, and the angle Δα between the inner surface of the sealing member 30 and the front end face of the ultrasonic microphone 12.

[0102] Therefore, in the present embodiment, the processor 543 calculates the relative speed of an object around the vehicle based on a corrected frequency obtained by multiplying the frequency of the reflected wave detected by the ultrasonic sensor 10 by a predetermined coefficient. Further, the coefficient is set to a value that changes according to the distance between the sealing member 30 and the ultrasonic sensor 10, specifically, the distance ΔL between the inner surface of the sealing member 30 and the front end of the ultrasonic microphone 12 of the corresponding ultrasonic sensor 10. In addition, the coefficient is set to a value that changes according to the angle between the sealing member 30 and the ultrasonic sensor 10, specifically, the angle Δα between the inner surface of the sealing member 30 and the front end surface of the ultrasonic microphone 12 of the corresponding ultrasonic sensor 10.

[0103] As a result, according to the present embodiment, even if the distance or angle between the sealing member 30 and the ultrasonic sensor 10 is different for each ultrasonic sensor 10, the relative speed of an object around the vehicle 1 can be calculated relatively accurately. Further, in the present embodiment, the coefficient used when calculating the corrected frequency is set to a value that changes based on both the distance ΔL and the angle Δα, but it may also be a value that changes based on only either one of the above.

[0104] <Effects and Modification Examples>

[0105] In the above-described embodiment, in the rear bumper 4, the sealing member 30 is disposed outside the ultrasonic sensor 10. As a result, the ultrasonic sensor 10 is not exposed to the outside, and a situation in which the aesthetic appearance of the rear bumper 4 provided with the ultrasonic sensor 10 deteriorates can be suppressed.

[0106] Further, in the present embodiment, the sealing member 30 is configured to have a natural frequency substantially the same as the natural frequency of the piezoelectric element 14 of the ultrasonic sensor 10 or to resonate due to the ultrasonic wave transmitted by the ultrasonic sensor 10. In particular, the sealing member 30 is formed of the same material as the piezoelectric element 14. As a result, a situation in which the ultrasonic wave transmitted from the ultrasonic sensor 10 is attenuated by the sealing member 30 can be suppressed, and in some cases, the ultrasonic wave transmitted from the ultrasonic sensor 10 is amplified in the sealing member 30.

[0107] In addition, in the above-described embodiment, the sealing member 30 is configured to have a natural frequency substantially the same as the natural frequency of the piezoelectric element 14 of the ultrasonic sensor 10. Alternatively, the sealing member 30 is configured to resonate due to the ultrasonic waves transmitted from the ultrasonic sensor 10. However, as long as the sealing member 30 is configured such that the amplitude of the ultrasonic waves transmitted from the ultrasonic sensor 10 and transmitted to the outside via the sealing member 30 is greater than the amplitude of the ultrasonic waves transmitted from the ultrasonic sensor 10 and transmitted to the outside via the rear bumper 4 when the rear bumper 4 is assumed to be provided instead of the sealing member 30, it may have a configuration different from the above-described configuration. Therefore, the sealing member 30 may also be formed of a material different from that of the piezoelectric element 14 of the ultrasonic sensor 10, such as metal. At this time, the sealing member 30 may also be formed to have a thickness thinner than that of the rear bumper 4, thereby suppressing attenuation more than the rear bumper 4. In addition, the sealing member 30 may be formed of the same material as the rear bumper 4 and have a thickness thinner than that of the rear bumper 4. In this case, it is also possible to suppress the attenuation of the ultrasonic waves transmitted from the ultrasonic sensor 10 due to the sealing member 30.

[0108] Alternatively, the sealing member 30 may not be configured such that the amplitude of the ultrasonic waves transmitted from the ultrasonic sensor 10 and transmitted to the outside via the sealing member 30 is greater than the amplitude of the ultrasonic waves transmitted from the ultrasonic sensor 10 and transmitted to the outside via the rear bumper 4 when the rear bumper 4 is assumed to be provided instead of the sealing member 30. Also in this case, as described above, by disposing the sealing member 30 outside the ultrasonic sensor 10 in the rear bumper 4, it is possible to suppress the deterioration of the appearance of the rear bumper 4.

[0109] In addition, in the above-described embodiment, the recess 8 is provided around the through-hole 7 of the rear bumper 4, and the sealing member 30 is disposed in the recess 8. However, the recess 8 may not be provided in the rear bumper 4. Figure 6 is a cross-sectional view similar to that showing the configuration around the rear bumper 4 according to one modification example and Figure 2 the same. In Figure 6 the modification example shown, the recess 8 is not provided in the rear bumper 4. Therefore, the sealing member 30' is disposed so as to cover the through-hole 7 on the outer surface 5 of the rear bumper 4. In particular, in Figure 6 the modification example shown, the edge portion of the sealing member 30' is formed such that the thickness gradually decreases toward the edge. Therefore, the joint between the sealing member 30' and the rear bumper 4 is formed relatively smoothly, thereby suppressing the deterioration of the appearance of the rear bumper 4.

[0110] In addition, the ultrasonic sensor 10 may have a configuration different from the above-described configuration. Figure 7 is a schematic cross-sectional view of the ultrasonic microphone 12' according to one modification example. In Figure 7In the illustrated modification, the ultrasonic microphone 12' has a housing 13' with a closed front end. In addition, in Figure 7 the illustrated modification, the ultrasonic microphone 12' is fixed inside the housing 13' on the front end side. In this case, ultrasonic waves having the same frequency as the natural frequency of the piezoelectric element 14 are also transmitted from the ultrasonic sensor 10. Therefore, in this case, the sealing member 30 is also configured to have a natural frequency substantially the same as the natural frequency of the piezoelectric element 14 of the ultrasonic microphone 12'.

[0111] In addition, in the above-described embodiment, in the ECU 54, the distance to an object around the vehicle 1 and the relative speed of the object are calculated based on the output of the ultrasonic sensor 10. However, a processing unit such as a processor or an arithmetic circuit may be provided in the ultrasonic sensor 10, and the distance to an object around the vehicle 1 and the relative speed of the object may be calculated based on the output of the ultrasonic sensor 10 in the processing unit of the ultrasonic sensor 10.

[0112] As described above, the preferred embodiments of the present disclosure have been described, but the present disclosure is not limited to the above-described embodiments, and various modifications and changes can be made within the scope described in the claims.

Claims

1. A sensor mounting structure, comprising: The outer plate member is provided with a through hole; an ultrasonic sensor disposed inside the through hole; and a sealing member covering the through hole and arranged to be separated from the ultrasonic sensor, The sensor mounting structure is configured such that ultrasonic waves transmitted from the ultrasonic sensor pass through the through hole and propagate to the outside via the sealing member, and reflected waves reflected by the outside pass through the through hole via the sealing member and are received by the ultrasonic sensor.

2. The sensor mounting structure according to claim 1, The sealing member is configured so that the amplitude of the ultrasonic wave transmitted from the ultrasonic sensor and transmitted to the outside through the sealing member is larger than the amplitude of the ultrasonic wave transmitted from the ultrasonic sensor and transmitted to the outside through the outer plate member when the outer plate member is provided instead of the sealing member.

3. The sensor mounting structure according to claim 1 or 2, The sealing member is configured to resonate due to the ultrasonic wave transmitted from the ultrasonic sensor.

4. The sensor mounting structure according to any one of claims 1 to 3, The sealing member is configured to have a natural frequency whose deviation from the natural frequency of a member that transmits ultrasonic waves in the ultrasonic sensor is within 5%.

5. The sensor mounting structure according to any one of claims 1 to 4, The thickness of the sealing member is thinner than the thickness of the outer plate member.

6. The sensor mounting structure according to any one of claims 1 to 5, The outer plate member has a plurality of through holes. One of the ultrasonic sensors and one of the sealing members are arranged for each through hole. The sealing member is configured to have thicknesses that are different from each other at least partially.

7. The sensor mounting structure according to any one of claims 1 to 6, The sealing member is formed of the same material as a member that transmits ultrasonic waves in the ultrasonic sensor.

8. The sensor mounting structure according to any one of claims 1 to 7, The outer plate member has a coating film on its outer surface side, The sealing member has a coating film formed of the same material as the coating film of the outer plate member on its outer surface side.

9. The sensor mounting structure according to any one of claims 1 to 8, The sealing member and the ultrasonic sensor are separated from each other by a non-conductive separator disposed between the sealing member and the ultrasonic sensor.

10. The sensor mounting structure according to any one of claims 1 to 9, The sensor mounting structure further includes a processing unit electrically connected to the ultrasonic sensor. The processing unit calculates the speed of the surrounding object based on a value obtained by multiplying the frequency of the reflected wave detected by the ultrasonic sensor by a predetermined coefficient, The coefficient changes based on at least one of a distance and an angle between the ultrasonic sensor and the sealing member.

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