Ultrasonic Sensor

Abstract

To provide a configuration having an improved design in an ultrasonic sensor retrofittable to a vehicle.SOLUTION: An ultrasonic sensor (1) includes a magnetic body (21), a diaphragm (22), and an electro-magnetic converter (32). The electric-magnetic converter is arranged so as to face the magnetic body with an outer panel (V3) of a vehicle interposed therebetween. The diaphragm is formed in a thin film shape having a film thickness direction along an axial direction parallel to a directivity axis (DA). The diaphragm is provided to be joined to an outer surface (V4) of the outer panel at an outer edge portion (23) in a radial direction intersecting the directivity axis, whereby it is capable of performing ultrasonic vibration. An inner space (27) which expands and contracts along an axial direction upon ultrasonic vibration of the diaphragm is formed between the diaphragm and the outer surface of the outer panel in a state where the outer edge portion of the diaphragm is joined to the outer surface of the outer panel.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to an ultrasonic sensor configured to be mounted on a vehicle by being attached to an outer panel of the vehicle. [Background technology]

[0002] Various ultrasonic sensors that can be retrofitted to a vehicle have been proposed in the past. For example, the ultrasonic sensor for a vehicle described in Patent Document 1 has a sensor body provided inside a cylindrical cover with a bottom, and can be attached to any position on the vehicle by attaching the adhesive part on the back side of the cover to any position on the vehicle. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 7-35846 Summary of the Invention [Problem to be solved by the invention]

[0004] In the vehicle ultrasonic sensor described in Patent Document 1, when mounted on the vehicle, the cover and the sensor main body protrude significantly from the vehicle body part (such as the bumper) to which they are attached, which is undesirable from the design standpoint.

[0005] The present invention has been made in consideration of the above-mentioned circumstances, etc. That is, the present invention provides, for example, an ultrasonic sensor that can be retrofitted to a vehicle, with an improved design. [Means for solving the problem]

[0006] The ultrasonic sensor (1) according to claim 1 is configured to be mounted on a vehicle (V) by being attached to an outer panel (V3) of the vehicle, A magnetic material (21); an electric-magnetic converter (32) having a function of converting an oscillating magnetic field between the magnetic body and an electric signal and disposed so as to face the magnetic body across the outer plate; a diaphragm (22) formed in a thin film shape having a thickness direction along an axial direction parallel to a directional axis (DA), and joined to an outer surface (V4) of the outer plate at an outer edge portion (23) in a radial direction intersecting the directional axis, so as to be capable of ultrasonic vibration; Equipped with One of the magnetic body and the electric-magnetic converter is fixed to the diaphragm so as to be ultrasonically vibrated in a manner of reciprocating along the axial direction, and the other is disposed to face an inner surface (V5) which is the back surface of the outer surface of the outer plate, so that ultrasonic vibration corresponding to the oscillating magnetic field is generated in the diaphragm, With the outer edge of the diaphragm joined to the outer surface of the outer plate, an internal space (27) is formed between the diaphragm and the outer surface of the outer plate, which expands and contracts along the axial direction in response to ultrasonic vibration of the diaphragm.

[0007] In addition, in each section of the application documents, each element may be given a reference symbol in parentheses. In this case, the reference symbol merely indicates an example of the correspondence between the element and the specific configuration described in the embodiment described later. Therefore, the present invention is not limited in any way by the description of the reference symbol. [Brief description of the drawings]

[0008] [Figure 1] 1 is a perspective view showing the appearance of a vehicle equipped with an ultrasonic sensor according to an embodiment; [Diagram 2] 2 is an enlarged cross-sectional view showing the configuration of the ultrasonic sensor shown in FIG. 1 according to one embodiment. [Diagram 3] FIG. 3 is a front view of the outer unit shown in FIG. 2. [Figure 4] 3 is a time chart showing an overview of application control of vibration damping power by the drive control unit shown in FIG. 2. [Diagram 5]3 is a flowchart showing an outline of a diagnostic operation performed by the circuit unit shown in FIG. 2. [Figure 6] 4 is a front view showing a schematic configuration of a modified example of the outer unit shown in FIG. 3. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] (Embodiment) Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Note that, if various modified examples applicable to one embodiment are inserted in the middle of a series of explanations related to the embodiment, it may hinder understanding of the embodiment. For this reason, the modified examples are not inserted in the middle of a series of explanations related to the embodiment, but are explained together after the series of explanations.

[0010] (In-vehicle configuration) 1, in this embodiment, the ultrasonic sensor 1 has a configuration as an on-board clearance sonar. That is, the ultrasonic sensor 1 is configured to be mounted on the vehicle V so as to be capable of detecting an object present around the vehicle V in a space outside the vehicle body SG. The space outside the vehicle body SG is an external space of the vehicle V. Hereinafter, the vehicle V on which the ultrasonic sensor 1 according to this embodiment is mounted may be referred to as the "own vehicle."

[0011] The vehicle V is a so-called four-wheeled automobile, and has a box-shaped body V1. A body panel V2 and a bumper V3, which are body parts constituting the outer panel, are attached to the body V1. The bumper V3 is provided at each of the front and rear ends of the body V1. The bumper V3 is made of synthetic resin, which is a material that is permeable to magnetic flux.

[0012] The ultrasonic sensor 1 is configured to be mounted on the vehicle V by being attached to the bumper V3. The state in which the ultrasonic sensor 1 is attached to the vehicle V, i.e., the bumper V3, is hereinafter referred to as the "vehicle-mounted state." Note that the ultrasonic sensor 1 is usually attached to and detached from the bumper V3 with the bumper V3 removed from the vehicle body V1. For this reason, the state in which the ultrasonic sensor 1 is attached to the bumper V3 is referred to as the "mounted state." The "vehicle-mounted state" also corresponds to the "mounted state."

[0013] Specifically, when mounted on the vehicle, a plurality of (e.g., four) ultrasonic sensors 1 are attached to the front bumper, i.e., the bumper V3 on the front side of the vehicle body V1. The plurality of ultrasonic sensors 1 attached to the front bumper are each arranged at different positions in the vehicle width direction. The "vehicle width direction" is a direction perpendicular to the vehicle overall length direction and the vehicle height direction. The "vehicle height direction" is a direction parallel to the direction of gravity when the vehicle V is stably placed on a horizontal plane in a drivable state. The "vehicle overall length direction" is a direction that defines the overall length of the vehicle V. Similarly, when mounted on the vehicle, a plurality of (e.g., four) ultrasonic sensors 1 are also attached to the rear bumper, i.e., the bumper V3 on the rear side of the vehicle body V1.

[0014] In the present disclosure, the bumper V3 is not provided with a mounting hole. The "mounting hole" is a through hole having an inner diameter corresponding to the outer shape of the ultrasonic sensor 1 for mounting the ultrasonic sensor 1. In other words, the ultrasonic sensor 1 has a configuration that allows it to be "post-installed" without forming a mounting hole later on in the bumper V3 for a non-mounted vehicle (i.e., the bumper V3 without a mounting hole), which is a vehicle V that has been shipped from the factory without the ultrasonic sensor 1 mounted thereon. The ultrasonic sensor 1 having such a configuration will be described in detail below.

[0015] (Ultrasonic Sensor) Fig. 2 shows one of a plurality of ultrasonic sensors 1 mounted on a bumper V3 in a vehicle-mounted state. Fig. 3 shows the appearance of an outer unit 2 constituting the ultrasonic sensor 1. Hereinafter, the configuration of the ultrasonic sensor 1 according to this embodiment will be described with reference to Figs. 1 to 3.

[0016] In this embodiment, the ultrasonic sensor 1 is configured to be able to transmit and receive ultrasonic waves. That is, the ultrasonic sensor 1 has an integrated transmission and reception configuration. Specifically, referring to FIG. 2, the ultrasonic sensor 1 is configured to transmit an ultrasonic exploration wave along a directional axis DA toward the vehicle exterior space SG. The "directional axis" is a virtual straight line extending from the ultrasonic sensor 1 along the transmission and reception direction of the ultrasonic waves, and serves as a reference for the directional angle. The "directional axis" may also be referred to as a "directional central axis" or a "detection axis." In addition, the ultrasonic sensor 1 is configured to receive a received wave including a reflected wave of the exploration wave by an object present around the vehicle from the vehicle exterior space SG, and to generate and output an object detection signal according to the reception result of the received wave.

[0017] For convenience of explanation, as shown in FIG. 2, a right-handed XYZ Cartesian coordinate system is set so that the X axis is parallel to the horizontal direction, the Y axis is parallel to the directional axis DA, and the Z axis is in the direction along the vehicle height direction. In this case, the direction parallel to the directional axis DA is called the "axial direction". The "tip side in the axial direction" is the transmission direction side of the search wave, and corresponds to the positive Y axis side in FIG. 2. In contrast, the "base end side in the axial direction" corresponds to the negative Y axis side in FIG. 2. Note that the Z axis is not necessarily parallel to the vehicle height direction. Therefore, depending on the shape of the bumper V3, the mounting position and mounting posture of the ultrasonic sensor 1, etc., the positive Z axis direction may be the same as the vertical upward direction or may be a direction intersecting the vertical upward direction.

[0018] Furthermore, any direction perpendicular to the axial direction is referred to as an "in-plane direction". The "in-plane direction" is a direction parallel to the XZ plane in FIG. 2. A shape in the in-plane direction, that is, a shape in a plane parallel to the XZ plane, or a shape projected onto the XZ plane, may be referred to as an "in-plane shape". The "in-plane direction" may also be referred to as a "radial direction" in some cases. The "radial direction" is a direction perpendicular to the directional axis DA and moving away from the directional axis DA. In other words, the "radial direction" is a direction in which a half-line extends when a virtual plane perpendicular to the directional axis DA is drawn with the intersection of the directional axis DA and the virtual plane as the starting point. In other words, the "radial direction" is a radial direction of a circle drawn in the virtual plane with the intersection of the virtual plane and the directional axis DA as the center.

[0019] The bumper V3 has a bumper outer surface V4 and a bumper inner surface V5. The bumper outer surface V4 is provided so as to face the space outside the vehicle body SG when attached to the vehicle body V1. The bumper inner surface V5 is the back side of the bumper outer surface V4, and is provided so as to face the space inside the vehicle body SN, which is the space inside the bumper V3, when attached to the vehicle body V1.

[0020] The ultrasonic sensor 1 includes an outer unit 2 and an inner unit 3. When mounted on the vehicle, the outer unit 2 is disposed so as to face the space outside the vehicle body SG. Specifically, the outer unit 2 is fixed onto the bumper outer surface V4. A fixing means for fixing the outer unit 2 to the bumper V3 will be described later. When mounted on the vehicle, the inner unit 3 is accommodated within the space inside the vehicle body SN. The inner unit 3 is fixed onto the bumper inner surface V5 by any fixing means.

[0021] In this embodiment, the outer unit 2 includes a magnetic body 21 and a diaphragm 22. The magnetic body 21 is fixed to the diaphragm 22 so as to be capable of ultrasonic vibration in a manner that moves back and forth along the axial direction. That is, the diaphragm 22 is configured to ultrasonically vibrate while undergoing bending deformation by fixedly supporting the magnetic body 21 that ultrasonically vibrates along the axial direction.

[0022] The magnetic body 21 is formed in a thin film having a thickness in the axial direction. The diaphragm 22 is formed in a thin film having a thickness along the axial direction. Specifically, the diaphragm 22 is formed in a predetermined shape by molding and cutting a non-magnetic synthetic resin film. The outer unit 2 is formed by forming a thin layer of the magnetic body 21 on the diaphragm 22 made of a synthetic resin film by vapor deposition or coating a magnetic material.

[0023] The diaphragm 22 has an outer surface 22a which faces the space outside the vehicle body SG when the diaphragm 22 is mounted on the vehicle, and an inner surface 22b which faces the bumper outer surface V4 when the diaphragm 22 is mounted on the vehicle. In this embodiment, the inner surface 22b of the diaphragm 22 is joined to the magnetic body 21.

[0024] The diaphragm 22 has an outer edge portion 23, which is the outer portion in the radial direction, and a vibrating portion 24 inside the outer edge portion 23. The outer edge portion 23 is formed in a flat plate shape having a thickness direction parallel to the axial direction and in a flange shape extending in the radial direction. The outer edge portion 23 is fixedly joined to the bumper outer surface V4 over almost the entirety. In other words, the diaphragm 22 has the outer edge portion 23 joined to the bumper outer surface V4 over almost the entirety, so that the vibrating portion 24, which is not joined to the bumper outer surface V4, is provided so as to be ultrasonically vibrated along the axial direction.

[0025] The diaphragm 22 is formed so that a step is provided along the axial direction between the outer edge portion 23 and the central portion 25 to which the magnetic body 21 is joined. Specifically, the central portion 25 is formed in a flat plate shape having a thickness direction parallel to the axial direction, and is disposed on the tip side in the axial direction from the outer edge portion 23. In addition, the intermediate portion 26 between the outer edge portion 23 and the central portion 25 has an outer shape that is approximately a truncated cone. That is, the diaphragm 22 is formed in a convex shape or a dome shape in which the central portion 25 protrudes from the outer edge portion 23 toward the tip side in the axial direction. Then, with the outer edge portion 23 of the diaphragm 22 joined to the bumper outer surface V4, an internal space 27 that expands and contracts along the axial direction in response to ultrasonic vibration of the diaphragm 22 is formed between the vibrating portion 24 of the diaphragm 22 and the bumper outer surface V4.

[0026] The outer edge 23 of the diaphragm 22 is bonded to the bumper outer surface V4 via an adhesive layer 28. Specifically, the adhesive layer 28 is fixedly bonded to the outer edge 23 of the diaphragm 22 in advance in a pre-attachment state before the ultrasonic sensor 1 is attached to the bumper V3. In this pre-attachment state, a release sheet (not shown) is attached to the surface of the adhesive layer 28 opposite to the side bonded to the inner surface 22b. The adhesive layer 28 is provided over almost the entire surface of the inner surface 22b corresponding to the outer edge 23.

[0027] A space maintaining material 29 is housed in the internal space 27. The space maintaining material 29 is disposed in the internal space 27 so as to be elastically deformable along the axial direction in response to ultrasonic vibration of the diaphragm 22. In this embodiment, the space maintaining material 29 is formed from an elastic non-magnetic synthetic resin such as foamed sponge.

[0028] The magnetic body 21 is formed in a substantially circular in-plane shape centered on the pointing axis DA. On the other hand, as shown in Fig. 3, in this embodiment, the diaphragm 22 is formed in an elliptical in-plane shape having a longitudinal direction in the Z-axis direction so that the first diaphragm dimension LD1 is longer than the second diaphragm dimension LD2. The first diaphragm dimension LD1 is the dimension of the diaphragm 22 in the Z-axis direction (i.e., the first in-plane direction) perpendicular to the film thickness direction of the diaphragm 22. The second diaphragm dimension LD2 is the dimension of the diaphragm 22 in the X-axis direction (i.e., the second in-plane direction) perpendicular to the film thickness direction of the diaphragm 22 and the Z-axis direction.

[0029] Further, the diaphragm 22 is formed so that the first vibratory portion dimension LM1 is longer than the second vibratory portion dimension LM2. The first vibratory portion dimension LM1 is the dimension of the vibratory portion 24 in the Z-axis direction (i.e., the first in-plane direction) perpendicular to the film thickness direction of the diaphragm 22. The second vibratory portion dimension LM2 is the dimension of the vibratory portion 24 in the X-axis direction (i.e., the second in-plane direction) perpendicular to the film thickness direction and the Z-axis direction of the diaphragm 22. That is, the in-plane shape of the vibratory portion 24 is formed in an elliptical shape that is approximately similar to the in-plane shape of the diaphragm 22. Therefore, the outer edge portion 23 is formed in an elliptical ring-shaped in-plane shape having a longitudinal direction in the Z-axis direction and a lateral direction in the X-axis direction.

[0030] 2 again, the inner unit 3 includes an inner case 31, an electric-magnetic converter 32, and a circuit section 33. The inner case 31 constituting the housing of the ultrasonic sensor 1 is formed in a box shape from insulating synthetic resin. The inner case 31 is configured to cover the electric-magnetic converter 32 and the circuit section 33 by being fixed to the bumper inner surface V5 by any fixing means such as double-sided tape.

[0031] The electric-magnetic converter 32 is disposed so as to face the bumper inner surface V5. That is, the ultrasonic sensor 1 is configured such that the magnetic body 21 and the electric-magnetic converter 32 are disposed so as to face each other across the bumper V3, so that ultrasonic vibrations corresponding to the oscillating magnetic field between the magnetic body 21 and the electric-magnetic converter 32 are generated in the diaphragm 22. Specifically, the electric-magnetic converter 32 is disposed in proximity to, in contact with, or bonded to the bumper inner surface V5 when mounted on the vehicle.

[0032] The electric-magnetic converter 32 has a function of converting between an oscillating magnetic field corresponding to the ultrasonic vibration of the magnetic body 21 and an electric signal. That is, when the electric-magnetic converter 32 is energized during transmission of the exploration wave, it generates an oscillating magnetic field to ultrasonically vibrate the magnetic body 21 and the diaphragm 22. Also, during reception, the electric-magnetic converter 32 generates a reception signal, which is an electric signal corresponding to the oscillating magnetic field generated by the ultrasonic vibration of the magnetic body 21 and the diaphragm 22. In this embodiment, the electric-magnetic converter 32 is configured by an inductor such as a coil.

[0033] The circuit unit 33 is electrically connected to the electric-magnetic converter 32. The circuit unit 33 is configured to output driving power to the electric-magnetic converter 32 during transmission, and to detect an object by receiving a reception signal from the electric-magnetic converter 32 during reception. Specifically, the circuit unit 33 includes a drive control unit 34, an object detection unit 35, and an abnormality detection unit 36.

[0034] The drive control unit 34 is provided to control the power application state to the electric-magnetic converter 32. Specifically, the drive control unit 34 is configured to apply a driving power for transmission to the electric-magnetic converter 32 during transmission. The drive control unit 34 is also configured to apply a vibration-damping power to the electric-magnetic converter 32 such that the magnetic body 21 and the electric-magnetic converter 32 attract each other for a predetermined time (i.e., a vibration-damping time T described later) from the stop of application of the driving power to the electric-magnetic converter 32. The drive control unit 34 is also configured to reduce the vibration-damping power as time passes when the application of the vibration-damping power is stopped. Furthermore, the drive control unit 34 is configured to apply a diagnostic power to the electric-magnetic converter 32 in a diagnostic mode to detect an abnormality in the outer unit 2, i.e., the diaphragm 22.

[0035] The object detection unit 35 is provided to detect objects around the vehicle by performing various signal processing such as filtering on the signal received from the electric-magnetic converter 32. The abnormality detection unit 36 ​​is provided to detect an abnormality in the diaphragm 22 based on the current flowing through the electric-magnetic converter 32 when diagnostic power is applied to the electric-magnetic converter 32 in the diagnosis mode.

[0036] (effect) Hereinafter, a process of attaching the ultrasonic sensor 1 according to this embodiment to the bumper V3 and an overview of the operation of the ultrasonic sensor 1 will be described with reference to the drawings, together with the effects achieved by the configuration.

[0037] In this embodiment, the outer unit 2, which is a component of the ultrasonic sensor 1 arranged on the vehicle exterior space SG side, is composed of a joint body of a magnetic body 21 and a diaphragm 22, and a space retaining material 29. The joint body is joined to the bumper exterior surface V4 by an adhesive layer 28, whereby the outer unit 2 is attached to the bumper V3.

[0038] Specifically, for example, when the adhesive layer 28 is an adhesive layer used in double-sided tape or the like, the outer unit 2 can be easily attached to the bumper V3 by abutting the outer unit 2 from which a release sheet (not shown) has been peeled off against the bumper outer surface V4. Also, the outer unit 2 can be easily removed from the bumper V3.

[0039] On the other hand, the inner unit 3 is fixed onto the bumper inner surface V5 by any fixing means. In this way, the ultrasonic sensor 1, in which the outer unit 2 and the inner unit 3 face each other across the bumper V3, is attached to the bumper V3.

[0040] When mounting the outer unit 2 and the inner unit 3 in this manner, there is no need to provide mounting holes in the bumper V3. Therefore, the ultrasonic sensor 1 according to this embodiment can be easily retrofitted to the vehicle V. Also, the process of mounting the ultrasonic sensor 1 to the bumper V3 can be simplified as much as possible.

[0041] When transmitting the exploration wave, the drive control unit 34 applies the driving power for transmission to the electric-magnetic converter 32. This causes an AC current of a predetermined frequency to flow through the electric-magnetic converter 32. Then, the electric-magnetic converter 32 generates an oscillating magnetic field of a predetermined frequency.

[0042] Here, a bumper V3 is interposed between the magnetic body 21 and the electric-magnetic converter 32. However, the bumper V3 is formed of a synthetic resin material that does not inhibit the electromagnetic interaction between the magnetic body 21 and the electric-magnetic converter 32. Therefore, the electromagnetic interaction between the magnetic body 21 and the electric-magnetic converter 32 is possible even if the bumper V3 is interposed between the magnetic body 21 and the electric-magnetic converter 32. Therefore, the oscillating magnetic field generated by the electric-magnetic converter 32 acts on the magnetic body 21 arranged to face the electric-magnetic converter 32 across the bumper V3. Then, the magnetic body 21 is ultrasonically vibrated along the axial direction by the action of the oscillating magnetic field. As a result, the diaphragm 22 is deflected and deformed while vibrating in the ultrasonic band, and the search wave is transmitted from the diaphragm 22 along the directional axis DA toward the space outside the vehicle body SG.

[0043] When receiving a received wave, the diaphragm 22 is excited by the received wave propagated from the space outside the vehicle body SG to the diaphragm 22, so that the diaphragm 22 vibrates at a frequency in the ultrasonic band while being deflected and deformed. Then, the magnetic body 21 is ultrasonically vibrated along the axial direction. This generates an oscillating magnetic field along the directional axis DA.

[0044] Here, as described above, the electromagnetic interaction between the magnetic body 21 and the electric-magnetic converter 32 is possible even if the bumper V3 is interposed between the magnetic body 21 and the electric-magnetic converter 32. Therefore, the oscillating magnetic field caused by the ultrasonic vibration along the axial direction of the magnetic body 21 acts on the electric-magnetic converter 32 arranged to face the magnetic body 21 across the bumper V3. Then, due to the action of this oscillating magnetic field, an induced current flows in the electric-magnetic converter 32. That is, the electric-magnetic converter 32 generates a received signal, which is an electric signal. By processing this received signal, the object detector 35 becomes able to detect an object corresponding to the reflected wave included in the received wave.

[0045] In this way, according to the above configuration, it is possible to realize good transmission and reception operations even if the bumper V3 is interposed between the magnetic body 21 and the electric-magnetic converter 32. Therefore, according to this embodiment, it is possible to achieve good transmission and reception performance in the ultrasonic sensor 1 having a configuration that allows it to be attached to the bumper V3 even if a mounting hole is not provided in the bumper V3.

[0046] In this embodiment, the outer unit 2 is configured such that the space retaining material 29 is covered with a joint of the thin-film magnetic material 21 and the film-like diaphragm 22 that holds the magnetic material 21. The space retaining material 29 can be formed as thin as possible within a range in which the internal space 27 is formed to an extent that the transmission sound pressure and reception sensitivity are sufficiently ensured. Therefore, in this configuration, the amount of protrusion of the outer unit 2 from the bumper outer surface V4 can be kept as small as possible. Therefore, with this configuration, it is possible to improve the design of the ultrasonic sensor 1 that can be retrofitted to the vehicle V more than ever before.

[0047] According to this embodiment, as shown in FIG. 3, in the vibrating portion 24, which is a portion of the diaphragm 22 capable of ultrasonic vibration, the first vibrating portion dimension LM1 along the vertical direction is longer than the second vibrating portion dimension LM2 along the horizontal direction. This allows the directivity angle in the YZ plane in the figure to be narrower than the directivity angle in the XY plane in the figure. Therefore, it is possible to effectively suppress erroneous detection caused by road surface reflection. In addition, it is possible to achieve a wide directivity angle in the horizontal direction with a simple device configuration. Furthermore, by forming the diaphragm 22 so that the first diaphragm dimension LD1 along the vertical direction is longer than the second diaphragm dimension LD2 along the horizontal direction, it is possible to realize such directivity with simple manufacturing and installation man-hours.

[0048] When transmission is stopped, i.e., when application of the driving power is stopped, the driving control unit 34 applies a vibration-damping power to the electric-magnetic converter 32 for a predetermined time such that the magnetic body 21 and the electric-magnetic converter 32 attract each other. FIG. 4 shows how such a vibration-damping power is applied. In the figure, the horizontal axis t indicates time, and the vertical axis indicates the current or voltage applied to the electric-magnetic converter 32. At time t1, application of the driving power ends. Then, during a vibration-damping time T between times t1 and t4, the vibration-damping power is applied to the electric-magnetic converter 32.

[0049] Specifically, first, the vibration damping power is increased in a first damping time T1 between times t1 and t2. After that, the vibration damping power is kept constant in a second damping time T2 between times t2 and t3. This allows the vibration of the diaphragm 22 to be damped quickly. Then, in a third damping time T3 between times t3 and t4, the vibration damping power is reduced over time. This allows unnecessary vibration to be suppressed as much as possible. Therefore, reverberation when transmission is stopped is effectively suppressed, thereby achieving good short-distance detection performance.

[0050] In the diagnostic mode, the drive control unit 34 applies diagnostic power to the electric-magnetic converter 32. The abnormality detection unit 36 ​​detects an abnormality in the diaphragm 22 based on the current flowing through the electric-magnetic converter 32 in the diagnostic mode.

[0051] Fig. 5 is a flowchart showing an outline of the operation of the circuit unit 33 in the diagnostic mode. In Fig. 5, "S" is an abbreviation of "step." A processor (not shown) provided in the circuit unit 33 starts executing the diagnostic mode at a predetermined timing.

[0052] When the diagnostic mode is started, first, in step 501, the drive control unit 34 applies diagnostic power to the electric-magnetic converter 32. Next, in step 502, the abnormality detection unit 36 ​​detects a diagnostic current, which is a current flowing through the electric-magnetic converter 32 due to the application of the diagnostic power.

[0053] If a crack occurs in the diaphragm 22 or if foreign matter adheres to the diaphragm 22, a stress change occurs, which causes the magnetic resistance to increase or decrease. Specifically, for example, the occurrence of a crack reduces the magnetic resistance, which increases the current flowing through the electric-magnetic converter 32. In contrast, the adhesion of foreign matter increases the magnetic resistance, which decreases the current flowing through the electric-magnetic converter 32.

[0054] Therefore, in step 503, the abnormality detection unit 36 ​​judges whether or not the detected diagnostic current is within the normal range. If the diagnostic current is within the normal range (i.e., step 503=YES), the abnormality detection unit 36 ​​judges that the diaphragm 22 is in a normal state in which no cracks or foreign matter are attached, and skips all the processes from step 504 onwards. This temporarily ends the diagnostic mode.

[0055] On the other hand, if the diagnostic current is outside the normal range (i.e., step 503=NO), the abnormality detection unit 36 ​​judges whether the detected diagnostic current is an abnormal value on the increasing side of the normal range. If the detected diagnostic current is an abnormal value on the increasing side of the normal range (i.e., step 504=YES), the abnormality detection unit 36 ​​judges the occurrence of a crack in the diaphragm 22 in step 505. Thereafter, the diagnostic mode is temporarily terminated. On the other hand, if the detected diagnostic current is an abnormal value on the decreasing side of the normal range (i.e., step 504=NO), the abnormality detection unit 36 ​​judges the adhesion of a foreign matter to the diaphragm 22 in step 506. Thereafter, the diagnostic mode is temporarily terminated. As described above, in this embodiment, it is possible to easily detect an abnormality in the diaphragm 22 based on the current flowing through the electric-magnetic converter 32.

[0056] (Modification) The present invention is not limited to the above embodiment. Therefore, the above embodiment can be modified as appropriate. Representative modified examples will be described below. In the following description of the modified examples, differences from the above embodiment will be mainly described. In addition, the same reference numerals are used for parts that are the same or equivalent to each other in the above embodiment and the modified examples. Therefore, in the following description of the modified examples, the description of the above embodiment can be appropriately used for components having the same reference numerals as the above embodiment, unless there is a technical contradiction or special additional explanation.

[0057] The object to which the ultrasonic sensor 1 is attached is not limited to the bumper V3. Specifically, for example, the ultrasonic sensor 1 can be attached to the vehicle body panel V2 as long as the vehicle body panel V2 is made of a material (e.g., synthetic resin) that does not inhibit the electromagnetic interaction between the magnetic body 21 and the electric-magnetic converter 32. That is, the material constituting the vehicle body part to which the ultrasonic sensor 1 is attached, for example, the vehicle body panel V2 and / or the bumper V3, is not particularly limited as long as it is a material that does not inhibit the electromagnetic interaction between the magnetic body 21 and the electric-magnetic converter 32. Such a "material that can transmit magnetic flux" may also be called a "material that transmits magnetic flux" or a "material that does not shield magnetic flux". As such a material, a non-magnetic material (e.g., a non-metallic material such as synthetic resin) that does not contain an additive component (e.g., a filler, etc.) made of a magnetic material such as iron may typically be used.

[0058] The ultrasonic sensor 1 is not limited to a configuration of an integrated transmitter and receiver. That is, for example, the ultrasonic sensor 1 may have a configuration capable of only transmitting a search wave. Alternatively, the ultrasonic sensor 1 may have only a function of receiving a search wave transmitted from another ultrasonic transmitter and reflected by an object present in the vicinity.

[0059] The configuration of each part of the ultrasonic sensor 1 is not limited to the above specific example. Specifically, for example, the in-plane shape of the magnetic body 21 is not limited to a circle, and may be a polygon such as a rectangle, a hexagon, or an octagon, an ellipse, or an oval.

[0060] The magnetic body 21 may be a magnet formed into a thin plate shape. In this case, the magnetic body 21 and the diaphragm 22 may be joined by any joining means such as an adhesive.

[0061] The in-plane shape of the diaphragm 22 is not limited to an ellipse, but may be a polygon, such as a rectangle, having a long side and a short side perpendicular to each other.

[0062] The in-plane shape of the diaphragm 22 may not be an ellipse having a longitudinal direction and a transverse direction perpendicular to each other, but may be a circle having no such longitudinal direction and transverse direction. For example, as shown in FIG. 6, the in-plane shape of the diaphragm 22 is a circle having a constant diaphragm diameter LD. Even in this case, the vibrating part 24 can be formed in a shape in which the first vibrating part dimension LM1 is longer than the second vibrating part dimension LM2 by adjusting the shape of the outer edge part 23, that is, the dimensional ratio or area ratio in the in-plane direction between the outer edge part 23 and the vibrating part 24. Specifically, the ratio of the outer edge part 23 in the Z-axis direction (i.e., the first in-plane direction) is made smaller than the ratio of the outer edge part 23 in the X-axis direction (i.e., the second in-plane direction).

[0063] The adhesive layer 28 may be omitted. That is, for example, the outer edge portion 23 of the diaphragm 22 may be directly bonded to the bumper V3 by heat welding or the like.

[0064] The space maintaining material 29 may be a fluid such as a gel-like substance that fills almost the entire interior space 27 .

[0065] The space retaining material 29 may be omitted. That is, the internal space 27 may be retained by the rigidity of the diaphragm 22.

[0066] The above embodiment has a configuration in which the magnetic body 21 is joined to the diaphragm 22, while the electric-magnetic converter 32 is provided in the inner unit 3. However, the present invention is not limited to such a configuration.

[0067] That is, it is possible to adopt a configuration in which the electric-magnetic converter 32 is joined to the diaphragm 22, while the magnetic body 21 is provided in the inner unit 3. In this case, a sheet-like or film-like inductor is used as the electric-magnetic converter 32.

[0068] In such a configuration, it is necessary to provide a wiring through hole in the bumper V3 for passing a connection wire for electrically connecting the electric-magnetic converter 32 arranged on the bumper outer surface V4 side and the circuit unit 33 arranged on the bumper inner surface V5 side. However, such a wiring through hole is sufficient as long as it can pass the connection wire. For this reason, such a wiring through hole is extremely small in diameter and extremely easily formed compared to a conventional mounting hole, and does not require the same positional accuracy and shape accuracy as a mounting hole. In addition, such a wiring through hole is externally hidden by the outer unit 2 by attaching the outer unit 2 to the bumper V3. Therefore, even with such a configuration, the possibility of retrofitting is not significantly hindered. Also, there is no particular inconvenience in terms of design.

[0069] Needless to say, the elements constituting the above-mentioned embodiment are not necessarily essential, except when expressly stated as essential or when considered to be obviously essential in principle. Furthermore, when the numbers, amounts, ranges, etc. of the components are mentioned, the present invention is not limited to the specific values, except when expressly stated as essential or when clearly limited to a specific value in principle. Similarly, when the shapes, directions, positional relationships, etc. of the components are mentioned, the present invention is not limited to the shapes, directions, positional relationships, etc., except when expressly stated as essential or when clearly limited to a specific shape, direction, positional relationship, etc. in principle.

[0070] The modified examples are not limited to the above examples. That is, for example, a plurality of modified examples other than those exemplified above may be combined with each other as long as there is no technical contradiction. [Explanation of symbols]

[0071] 1 Ultrasonic sensor 21 Magnetic material 22 Diaphragm 23 Outer edge 27 Interior Space 32 Electric-magnetic converter DA directional axis V3 Bumper V4 Bumper outer surface V5 Bumper inner surface

Claims

1. An ultrasonic sensor (1) configured to be mounted on a vehicle (V) by being attached to an outer panel (V3) of the vehicle, A magnetic material (21); an electric-magnetic converter (32) having a function of converting an oscillating magnetic field between the magnetic body and an electric signal and disposed so as to face the magnetic body across the outer plate; a diaphragm (22) formed in a thin film shape having a thickness direction along an axial direction parallel to a directional axis (DA), and joined to an outer surface (V4) of the outer plate at an outer edge portion (23) in a radial direction intersecting the directional axis, so as to be capable of ultrasonic vibration; Equipped with One of the magnetic body and the electric-magnetic converter is fixed to the diaphragm so as to be ultrasonically vibrated in a manner of reciprocating along the axial direction, and the other is disposed to face an inner surface (V5) which is the back surface of the outer surface of the outer plate, so that ultrasonic vibration corresponding to the oscillating magnetic field is generated in the diaphragm, With the outer edge of the diaphragm bonded to the outer surface of the outer plate, an internal space (27) is formed between the diaphragm and the outer surface of the outer plate, the internal space expanding and contracting along the axial direction in response to ultrasonic vibration of the diaphragm. Ultrasonic sensor.

2. The outer edge of the diaphragm is bonded to the outer surface of the outer plate via an adhesive layer (28).

2. The ultrasonic sensor of claim 1.

3. The ultrasonic vibration device further includes a space retainer (29) disposed in the internal space so as to be elastically deformable along the axial direction in response to ultrasonic vibration of the diaphragm.

3. The ultrasonic sensor according to claim 1 or 2.

4. The magnetic body is bonded to the diaphragm, the electric-magnetic transducer is disposed opposite the inner surface of the outer panel; The ultrasonic sensor according to any one of claims 1 to 3.

5. The magnetic material is formed into a thin film.

5. The ultrasonic sensor according to claim 4.

6. The diaphragm includes a vibrating portion (24) that is arranged to be ultrasonically vibrated on the inner side in the radial direction from the outer edge portion, When a direction perpendicular to the film thickness direction is defined as a first in-plane direction, a direction perpendicular to the film thickness direction and the first in-plane direction is defined as a second in-plane direction, a dimension of the vibratory part in the first in-plane direction is defined as a first vibratory part dimension, and a dimension of the vibratory part in the second in-plane direction is defined as a second vibratory part dimension, the diaphragm is formed such that the first vibratory part dimension is longer than the second vibratory part dimension. The ultrasonic sensor according to any one of claims 1 to 5.

7. When a dimension of the diaphragm in the first in-plane direction is defined as a first diaphragm dimension and a dimension of the diaphragm in the second in-plane direction is defined as a second diaphragm dimension, the diaphragm is formed such that the first diaphragm dimension is longer than the second diaphragm dimension.

7. The ultrasonic sensor according to claim 6.

8. A drive control unit (34) for controlling a state of power application to the electric-magnetic converter is further provided. the drive control unit applies, to the electric-magnetic converter, a vibration suppression power such that the magnetic body and the electric-magnetic converter are attracted to each other for a predetermined time from the stop of application of the drive power for transmission; The ultrasonic sensor according to any one of claims 1 to 7.

9. The drive control unit reduces the vibration damping power over time.

9. The ultrasonic sensor of claim 8.

10. The drive control unit further includes an abnormality detection unit (36) that detects an abnormality in the diaphragm based on a current flowing through the electric-magnetic converter when a diagnostic power is applied to the electric-magnetic converter by the drive control unit.

10. The ultrasonic sensor according to claim 8 or 9.

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