JP2016070750A - Ultrasonic transmitter receiver - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ultrasonic transmitter receiver capable of preventing an elastic member from being exposed to the outside and suppressing the variation in radiation characteristic of an ultrasonic sensor.SOLUTION: The ultrasonic transmitter receiver includes: an ultrasonic sensor 1 having a transmission/reception surface 1a for transmitting/receiving an ultrasonic wave; a case 2 for storing the ultrasonic sensor 1 while the transmission/reception surface 1a is exposed from an opening 2a; an elastic member 4 disposed between the inner surface of the case 2 and the ultrasonic sensor 1; and a flange unit 3 that is formed so as to project from the edge of the opening 2a to the inside, and abuts on and cover the elastic member 4 facing the opening 2a.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an ultrasonic transmission / reception apparatus that is attached to, for example, a vehicle bumper, and that is used as an obstacle detection apparatus that detects an obstacle around the vehicle by transmitting ultrasonic waves and receiving reflected waves thereof.

  Conventionally, an ultrasonic device has been provided with a vibration element that generates a voltage by the inverse piezoelectric effect when it receives ultrasonic waves reflected by an object that blocks the propagation of the transmitted ultrasonic waves by oscillating and transmitting ultrasonic waves by the piezoelectric effect. Acoustic wave sensors are known. An ultrasonic sensor is attached to a bumper of a vehicle, for example, and is used for an obstacle detection device that detects an obstacle around the vehicle.

  For example, Patent Document 1 discloses an ultrasonic transmission / reception apparatus including an ultrasonic sensor provided with a vibration element, a case that houses the ultrasonic sensor, and an elastic member that is disposed between the case and the ultrasonic sensor. Is described. This ultrasonic transmission / reception apparatus is attached to the bumper via the case so that a transmission / reception surface for transmitting / receiving ultrasonic waves by an ultrasonic sensor is exposed to the outside from a through hole formed in the bumper of the vehicle.

JP 2001-289939 A

In the ultrasonic transmission / reception apparatus disclosed in Patent Document 1, the elastic member is exposed to the outside together with the transmission / reception surface of the ultrasonic sensor when attached to a vehicle bumper or the like. The elastic member limits the vibration of the ultrasonic sensor, and is formed of a rubber material such as silicon rubber, for example.
However, rubber materials such as silicone rubber generally have poor paint adhesion, and it is difficult to paint with the same color as the transmission / reception surface of the ultrasonic sensor and the bumper. For this reason, if an elastic member remains exposed, an elastic member will be conspicuous from the outside and design property will fall.

  Further, when the relative position between the ultrasonic sensor and the elastic member, that is, the range covered by the elastic member with the ultrasonic sensor is shifted, the range in which the vibration of the side surface of the ultrasonic sensor is limited by the elastic member also changes. Since the vibration state of the side surface close to the transmitting / receiving surface of the ultrasonic sensor also affects the flexural vibration of the transmitting / receiving surface, the radiation characteristics of the ultrasonic sensor change if the range of vibrations restricted by the elastic member on the side surface of the ultrasonic sensor changes. Also changes.

When the ultrasonic sensor has a bottomed cylindrical shape with the bottom surface as a transmission / reception surface, and the elastic member has a cylindrical shape covering the outer periphery of the cylindrical portion of the ultrasonic sensor, the transmission / reception surface of the ultrasonic sensor and the elasticity as in Patent Document 1 are used. When the ultrasonic transmission / reception device is attached to the bumper of the vehicle with the member exposed to the outside, the elastic member moves easily in a direction along the ultrasonic sensor due to vibration during traveling of the vehicle, and thus the position is easily displaced.
That is, since the relative position between the ultrasonic sensor and the elastic member is likely to change, the radiation characteristics of the ultrasonic sensor vary.

  The present invention has been made to solve the above-described problems, and an object thereof is to provide an ultrasonic transmission / reception apparatus that prevents the elastic member from being exposed to the outside and stabilizes the relative position of the ultrasonic sensor and the elastic member. And

  An ultrasonic transmission / reception apparatus according to the present invention includes an ultrasonic sensor having a transmission / reception surface for transmitting / receiving ultrasonic waves, a case for accommodating the ultrasonic sensor by exposing the transmission / reception surface from the opening, an inner surface of the case, and the ultrasonic sensor And an eaves part formed so as to project inward from the edge part of the opening part and abut against the elastic member facing the opening part.

  According to the present invention, it is possible to prevent the elastic member from being exposed to the outside and to stabilize the relative positions of the ultrasonic sensor and the elastic member.

It is a front view which shows the ultrasonic transmitter / receiver which concerns on Embodiment 1 of this invention. FIG. 2 is a cross-sectional arrow view of the ultrasonic transmission / reception apparatus of FIG. 1 taken along line AA. It is a graph which shows the relationship between the sensor protrusion length of an ultrasonic sensor, and a radiation sound pressure. It is the cross-sectional arrow figure which cut the modification 1 of the ultrasonic transmitter-receiver which concerns on Embodiment 1 with the AA line. It is the cross-sectional arrow figure which cut the modification 2 of the ultrasonic transmitter-receiver which concerns on Embodiment 1 by the AA line. It is the cross-sectional arrow figure which cut the modification 3 of the ultrasonic transmitter-receiver which concerns on Embodiment 1 with the AA line.

Embodiment 1 FIG.
FIG. 1 is a front view showing an ultrasonic transmission / reception apparatus according to Embodiment 1 of the present invention, and shows a state in which the ultrasonic transmission / reception apparatus is viewed from the transmission / reception surface 1 a side of the ultrasonic sensor 1. The ultrasonic transmission / reception apparatus according to Embodiment 1 is attached to, for example, a bumper in front of or behind a vehicle, transmits an ultrasonic wave to the front or rear of the vehicle, and receives an ultrasonic wave reflected by an obstacle to cause an obstacle. Used to detect the presence or absence of an object.

  In FIG. 1, a transmission / reception surface 1 a is an end surface that transmits and receives ultrasonic waves with the ultrasonic sensor 1. Further, the case 2 has an opening 2a formed on the end surface 2b, and the ultrasonic sensor 1 is accommodated by exposing the transmission / reception surface 1a from the opening 2a. The opening 2a is formed with a flange 3 projecting inward from the edge thereof. The ultrasonic transmission / reception apparatus is attached to a bumper or the like via the case 2.

  As shown in FIG. 1, the elastic member described later with reference to FIG. 2 is covered with the flange 3 and is not exposed to the outside. Therefore, when the ultrasonic transmission / reception apparatus according to Embodiment 1 is attached to a vehicle bumper or the like, it is not necessary to paint the elastic member, and the transmission / reception surface 1a and the collar 3 can be painted in the same color as the bumper. . Accordingly, the bumper, the transmission / reception surface 1a, and the flange 3 are all the same color, and the design is improved.

  FIG. 2 is a cross-sectional arrow view of the ultrasonic transmission / reception apparatus of FIG. 1 taken along line AA. As shown in FIG. 2, the ultrasonic transmission / reception device according to the first embodiment includes an ultrasonic sensor 1, a case 2, a flange portion 3, and an elastic member 4. The ultrasonic sensor 1 includes a metal case 1b, a vibration element 1c, and an input / output terminal 1d.

The metal case 1b is a bottomed cylindrical case, and the vibration element 1c is bonded to the inner surface of the bottom. The vibration element 1c is formed using a disk-shaped piezoelectric element. When a voltage is applied, the vibration element 1c expands and contracts in the surface direction (diameter direction) due to the piezoelectric effect, and oscillates an ultrasonic wave. To output an electrical signal. Thereby, the bottom surface of the metal case 1b functions as a transmission / reception surface 1a for transmitting and receiving ultrasonic waves.
Note that the metal case 1b may be filled with a filler to seal the opening side of the metal case 1b.

  The input / output terminal 1d is a plus-side and minus-side lead wire that supplies a drive voltage to the vibration element 1c and sends a signal from the vibration element 1c. Although not shown, the input / output terminal 1d is electrically connected to a drive circuit for driving the ultrasonic sensor 1 and a signal processing circuit for amplifying a signal from the vibration element 1c and performing signal processing such as noise removal. Connected.

The case 2 is a case having an opening 2a on the end surface 2b and having a flange 3 that protrudes inward from the edge of the opening 2a, with the transmission / reception surface 1a exposed from the opening 2a. The ultrasonic sensor 1 is accommodated. The case 2 is preferably formed of the same material as the attachment portion to which the ultrasonic transmission / reception device is attached. For example, the case 2 is formed of the same resin material as a vehicle bumper material such as polypropylene.
In terms of manufacturability, it is desirable to provide a through portion in at least a part of the case 2 opposite to the opening 2a.

The elastic member 4 is a cylindrical elastic member that covers the side surface of the metal case 1b of the ultrasonic sensor 1, and is formed of a rubber material such as silicon rubber. By accommodating the ultrasonic sensor 1 in the case 2, the elastic member 4 is disposed between the inner surface of the case 2 and the ultrasonic sensor 1.
When flexural vibration is generated on the transmission / reception surface 1a (bottom surface) of the metal case 1b due to the vibration of the vibration element 1c, the side surface of the metal case 1b is also vibrated in conjunction with this. The vibration state of the side surface of the metal case 1b also affects the flexural vibration of the transmission / reception surface 1a.
The elastic member 4 limits the vibration of the side surface of the metal case 1b so that the ultrasonic sensor 1 can perform appropriate vibration on the transmission / reception surface 1a. Further, the elastic member 4 is disposed between the inner surface of the case 2 and the ultrasonic sensor 1, thereby preventing vibration from being transmitted to the case 2.

Further, the flange 3 is formed so as to protrude inward from the edge of the opening 2a, and as shown in FIG. 2, covers the elastic member 4 facing the opening 2a. Therefore, as shown in FIG. 1, the elastic member 4 is shielded by the flange 3 and is not exposed to the outside from the opening 2a.
Furthermore, the movement of the elastic member 4 in the direction along the ultrasonic sensor 1 is restricted by the flange 3, and the elastic member 4 is fixed at the initial position. Thereby, the relative position of the ultrasonic sensor 1 and the elastic member 4 is stabilized, and variation in radiation characteristics of the ultrasonic sensor 1 can be reduced.
As shown in FIG. 2, the ultrasonic sensor 1 is disposed so as to protrude from the elastic member 4 by a predetermined length L on the opening 2a side.

Next, the operation will be described.
In the ultrasonic sensor 1, when a voltage is applied to the vibration element 1c via the input / output terminal 1d, the vibration element 1c expands and contracts in the diameter direction. At this time, since the bottom surface (transmission / reception surface 1a) of the metal case 1b does not expand and contract in the diameter direction and does not change, flexural vibration is generated on the transmission / reception surface 1a of the metal case 1b due to expansion and contraction of the vibration element 1c. Due to this flexural vibration, ultrasonic waves are radiated from the transmitting and receiving surface 1a into the air.

  On the other hand, in conjunction with the occurrence of flexural vibration on the transmission / reception surface 1a of the metal case 1b, vibration is also generated on the side surface of the metal case 1b. The vibration state of the side surface of the metal case 1b also affects the flexural vibration of the bottom surface (transmission / reception surface 1a). The vibration of the side surface of the metal case 1b can be limited by covering the side surface of the metal case 1b with the elastic member 4.

In order to appropriately vibrate the side surface of the metal case 1b and radiate ultrasonic waves from the transmission / reception surface 1a with an appropriate radiation sound pressure, the ultrasonic sensor 1 has a predetermined length L (hereinafter referred to as sensor protrusion length). It is necessary to protrude from the elastic member 4 to the opening 2a side.
Note that the sensor protruding length L is not less than the thickness D of the metal case 1 b and does not protrude from the case 2.

When the elastic member 4 covers almost the entire side surface of the metal case 1b (L≈0), the outer peripheral portion of the transmission / reception surface 1a is rigid and the flexural vibration is suppressed. On the other hand, when the sensor protruding length L is in the above range, the vibration of the side surface portion near the transmission / reception surface 1a of the metal case 1b is not limited, and the outer peripheral portion of the transmission / reception surface 1a is not rigid. Thereby, the influence on the flexural vibration of the transmission / reception surface 1a is reduced, and the radiation sound pressure is improved.
Note that the relative positions of the ultrasonic sensor 1 and the elastic member 4 at this time are fixed by restricting the movement of the elastic member 4 by the flange 3.

FIG. 3 is a graph showing the relationship between the sensor protrusion length of the ultrasonic sensor 1 and the radiation sound pressure obtained by simulation. In FIG. 3, the horizontal axis represents the sensor protrusion length L indicating the relative positional relationship between the ultrasonic sensor 1 and the elastic member 4, and the vertical axis represents the radiation sound pressure of the ultrasonic wave.
As can be seen from FIG. 3, when the sensor protrusion length L is changed, the radiation sound pressure is also changed accordingly. That is, when the sensor protrusion length L changes, the radiation characteristic of the ultrasonic sensor 1 varies.

  On the other hand, in the ultrasonic transmission / reception apparatus according to the present invention, the movement of the elastic member 4 is restricted by the collar portion 3, and the relative positions of the ultrasonic sensor 1 and the elastic member 4 are fixed. That is, since the sensor protrusion length L of the ultrasonic sensor 1 does not change and a predetermined length is maintained, the radiation sound pressure can be stabilized and variations in radiation characteristics of the ultrasonic sensor 1 can be reduced. it can.

  Furthermore, since the ultrasonic sensor 1 protrudes from the elastic member 4 to the opening 2a side by the sensor protruding length L, the vibration of the side surface of the bottom surface portion (transmission / reception surface 1a) of the metal case 1b is not limited. For this reason, the outer peripheral portion of the transmission / reception surface 1a is not rigid, and the influence on the flexural vibration of the transmission / reception surface 1a is reduced. As a result, a good radiation sound pressure is exhibited.

  As shown in FIG. 2, an inclined surface that goes down toward the transmitting / receiving surface 1 a is formed on the entire circumference or a part of the collar portion 3. By doing in this way, since the opening surface of case 2 which the transmission / reception surface 1a exposes spreads substantially, the collar part 3 can function as a horn. Thereby, the directivity characteristic of the ultrasonic sensor 1 is sharpened, and the effect of increasing the radiation sound pressure is obtained.

The inclination of the inclined surface corresponds to the horn shape.
Therefore, as shown in FIG. 2, the horn shape can be a conical horn by giving the inclined surface a linear inclination represented by a linear function.

Moreover, although the case where the inclined surface was provided only in the collar part 3 was shown in FIG. 2, you may provide an inclined surface to the part including the end surface 2b of the case 2. FIG.
That is, an inclined surface that continuously extends from the end surface 2b of the case 2 to the flange portion 3 toward the transmission / reception surface 1a is formed on the entire circumference or a part of the flange portion 3 and the end surface 2b of the case 2.
By comprising in this way, the opening surface of case 2 which the transmission / reception surface 1a exposes can be expanded further substantially. Thereby, it is possible to further sharpen the directivity and increase the radiation sound pressure.

FIG. 4 is a cross-sectional arrow view of modification 1 of the ultrasonic transmission / reception apparatus according to Embodiment 1 cut along line AA. The ultrasonic transmission / reception apparatus shown in FIG. 4 has basically the same configuration as that shown in FIG. 2, but is different in that it includes a flange 3a. The eaves part 3a has an inclined surface inclined in a curved shape represented by a quadratic function.
By comprising in this way, the opening part of case 2 which the transmission / reception surface 1a exposes can be functioned as a parabolic horn. This also substantially widens the opening surface, sharpens the directivity of the ultrasonic sensor 1 and increases the radiation sound pressure.

In FIG. 4, the case where the inclined surface is provided only on the flange portion 3 a is shown, but the inclined surface may be provided up to a portion including the end surface 2 b of the case 2.
That is, an inclined surface that continuously extends from the end surface 2b of the case 2 to the flange portion 3a toward the transmission / reception surface 1a is formed on the entire circumference or a part of the end surface 2b of the flange portion 3a and the case 2.
By comprising in this way, the opening surface of case 2 which the transmission / reception surface 1a exposes can be expanded further substantially. Thereby, it is possible to further sharpen the directivity and increase the radiation sound pressure.

FIG. 5 is a cross-sectional arrow view of modification 2 of the ultrasonic transmission / reception apparatus according to Embodiment 1 taken along line AA. The ultrasonic transmission / reception apparatus shown in FIG. 5 has basically the same configuration as that shown in FIG. 2 except that it includes a flange 3b. The flange 3b has an inclined surface that is inclined in a curved line represented by an exponential function.
By comprising in this way, the opening part of case 2 which the transmission / reception surface 1a exposes can be functioned as an exponential horn. This also substantially widens the opening surface, sharpening the directivity of the ultrasonic sensor 1 and increasing the radiation sound pressure.

In addition, although the case where the inclined surface was provided only in the collar part 3b was shown in FIG. 5, you may provide an inclined surface to the part including the end surface 2b of the case 2. FIG.
That is, an inclined surface that continuously extends from the end surface 2b of the case 2 to the flange portion 3b toward the transmission / reception surface 1a is formed on the entire circumference or a part of the flange portion 3b and the end surface 2b of the case 2.
By comprising in this way, the opening surface of case 2 which the transmission / reception surface 1a exposes can be expanded further substantially. Thereby, it is possible to further sharpen the directivity and increase the radiation sound pressure.

FIG. 6 is a cross-sectional arrow view of modification 3 of the ultrasonic transmission / reception apparatus according to Embodiment 1 cut along line AA. The ultrasonic transmission / reception apparatus shown in FIG. 6 has basically the same configuration as that shown in FIG. 2 except that it includes a flange 3c. The eaves part 3c has an inclined surface inclined in a curved shape represented by a hyperbolic function.
By comprising in this way, the opening part of case 2 which the transmission / reception surface 1a exposes can be functioned as a hyperbolic horn.
This also substantially widens the opening surface, so that the directivity characteristics of the ultrasonic sensor 1 are sharpened and the radiation sound pressure is increased.

6 shows the case where the inclined surface is provided only on the flange 3c, the inclined surface may be provided up to a portion including the end surface 2b of the case 2.
That is, an inclined surface that continuously extends from the end surface 2b of the case 2 to the flange portion 3c toward the transmission / reception surface 1a is formed on the entire circumference or a part of the flange portion 3c and the end surface 2b of the case 2.
By comprising in this way, the opening surface of case 2 which the transmission / reception surface 1a exposes can be expanded further substantially. Thereby, it is possible to further sharpen the directivity and increase the radiation sound pressure.

As described above, according to the first embodiment, the ultrasonic transmission / reception apparatus exposes the transmission / reception surface 1a from the ultrasonic sensor 1 having the transmission / reception surface 1a for transmitting and receiving ultrasonic waves and the ultrasonic wave by opening the transmission / reception surface 1a. A case 2 that accommodates the sensor 1, an elastic member 4 that is disposed between the inner surface of the case 2 and the ultrasonic sensor 1, and is formed to project inward from the edge of the opening 2a, and faces the opening 2a. And a collar portion 3, 3 a to 3 c that contacts and covers the elastic member 4.
By comprising in this way, the elastic member 4 which faced the opening part 2a is coat | covered with the collar parts 3 and 3a-3c, and the elastic member 4 is not exposed outside.
The case 2 can be made of the same material (for example, resin material) as the mounting part such as a bumper, and the flange parts 3, 3 a to 3 c are integrally formed of the same material as the case 2.
Therefore, the collar parts 3 and 3a-3c can be painted with the same color as the transmission / reception surface 1a and the bumper of the ultrasonic sensor 1, and the design can be improved.
Further, the elastic member 4 is restricted from moving toward the opening 2a by abutting against the flanges 3, 3a to 3c, so that the relative positions of the ultrasonic sensor 1 and the elastic member 4 can be stabilized. it can.
Therefore, variation in radiation characteristics of the ultrasonic sensor 1 can be reduced.

  Moreover, according to this Embodiment 1, the ultrasonic sensor 1 protrudes rather than the elastic member 4 to the opening part 2a side. With this configuration, the outer peripheral portion of the transmission / reception surface 1a of the ultrasonic sensor 1 is not rigid by the elastic member 4, and the influence on the flexural vibration of the transmission / reception surface 1a is reduced. Thereby, a favorable radiation sound pressure can be obtained.

  Furthermore, according to the first embodiment, the flanges 3, 3 a to 3 c have the inclined surfaces that descend to the transmission / reception surface 1 a side. As a result, the opening surface of the case 2 where the transmission / reception surface 1a is exposed substantially expands, so that the flange portion 3 functions as a horn. Therefore, the directivity characteristics of the ultrasonic sensor 1 can be sharpened, and the effect of increasing the radiation sound pressure can be obtained.

  Furthermore, according to the first embodiment, the end surface 2b of the case 2 having the flange portions 3, 3a to 3c and the opening 2a is continuously transmitted and received from the end surface 2b of the case 2 to the flange portions 3, 3a to 3c. It has an inclined surface that goes down to the side of 1a. As a result, the opening surface of the case 2 from which the transmission / reception surface 1a is exposed can be substantially further widened, so that it is possible to further sharpen the directivity and increase the radiation sound pressure.

  Furthermore, according to the first embodiment, the above-described inclined surface is inclined linearly represented by a linear function. By comprising in this way, the collar part 3 or the end surface 2b of the case 2, and the collar part 3 can be functioned as a conical horn.

  Furthermore, according to the first embodiment, the above-described inclined surface is inclined in a curved shape represented by a quadratic function. By comprising in this way, the collar part 3a or the end surface 2b of the case 2, and the collar part 3a can be functioned as a parabolic horn.

  Furthermore, according to the first embodiment, the above-described inclined surface is inclined in a curved shape represented by an exponential function. By comprising in this way, the collar part 3b or the end surface 2b of the case 2, and the collar part 3b can be functioned as an exponential horn.

  Further, according to the first embodiment, the above-described inclined surface is inclined in a curved shape represented by a hyperbolic function. By comprising in this way, the collar part 3c or the end surface 2b of the case 2, and the collar part 3c can be functioned as a hyperbolic horn.

  In the present invention, any component of the embodiment can be modified or any component of the embodiment can be omitted within the scope of the invention.

  DESCRIPTION OF SYMBOLS 1 Ultrasonic sensor, 1a Transmission / reception surface, 1b Metal case, 1c Vibration element, 1d Input / output terminal, 2 Case, 2a Opening part, 2b End surface, 3,3a-3c collar part, 4 Elastic member.

Claims (8)

An ultrasonic sensor having a transmitting and receiving surface for transmitting and receiving ultrasonic waves;
A case for accommodating the ultrasonic sensor by exposing the transmission / reception surface from an opening;
An elastic member disposed between the inner surface of the case and the ultrasonic sensor;
An ultrasonic transmission / reception apparatus comprising: a collar portion that is formed to project inward from an edge portion of the opening portion and that contacts and covers the elastic member facing the opening portion.   The ultrasonic transmission / reception apparatus according to claim 1, wherein the ultrasonic sensor protrudes more toward the opening than the elastic member.   The ultrasonic transmission / reception apparatus according to claim 1, wherein the flange has an inclined surface that descends toward the transmission / reception surface.   The end surface of the case having the flange and the opening has an inclined surface that continuously extends from the end surface of the case to the flange to the side of the transmission / reception surface. The ultrasonic transmission / reception apparatus described.   The ultrasonic transmission / reception apparatus according to claim 3, wherein the inclined surface is inclined linearly represented by a linear function.   The ultrasonic transmission / reception apparatus according to claim 3, wherein the inclined surface is inclined in a curved shape represented by a quadratic function.   The ultrasonic transmission / reception apparatus according to claim 3 or 4, wherein the inclined surface is inclined in a curved shape represented by an exponential function.   The ultrasonic transmission / reception apparatus according to claim 3 or 4, wherein the inclined surface is inclined in a curved shape represented by a hyperbolic function.

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