JP2010147668A - Ultrasonic transducer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a distance measurement propagation ultrasonic transducer which, especially, detects the existence of an object, or surveys the distance to the object, and has a wide structure which is optimal for ultrasonic propagation. <P>SOLUTION: The ultrasonic transducer has a cup-shaped casing, equipped with a side wall and of which the internal cross-section which is perpendicular to the center axis presents substantially a dumbbell shape. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an ultrasonic transducer, and more particularly to an ultrasonic transducer with an optimized ultrasonic propagation range that detects the presence of an object or measures a distance from the object.

  Ultrasonic transducers are used in various application fields that need to detect an object, and typical applications include detection and measurement of a target object. Detection. In these applications, ultrasonic transducers use piezoelectric elements to generate ultrasonic waves for detection, most of which are usually used as ultrasonic transceivers. That is, the ultrasonic transducer has two functions, that is, ultrasonic radiation for scanning and / or length measurement and reception of reflected ultrasonic waves.

  In either radiation or reception mode, the transmission and reception shape of the ultrasonic transducer greatly affects its function, for example, when used for obstacle detection behind a car, Both cover areas must be formed into suitable shapes. In general, both the transmission and reception coverage areas need to be wide in the horizontal direction and narrow in the vertical direction. By widening the transmission coverage area in the horizontal direction, obstacle detection is possible. The range of possible angles can be effectively expanded, and interference by reflected waves can be effectively reduced by narrowing the coverage range of received waves in the vertical direction.

  The shape of the cover area in the reception mode of the ultrasonic transducer used in the obstacle detection system behind the automobile should be the same or almost the same as the shape of the cover area in the radiation mode. Even in applications such as length, the above conditions are required.

  In order to satisfy the above condition, conventionally, the operating range of the ultrasonic transducer is increased to narrow the cover range in the vertical direction. However, in this method, the cover range in the horizontal direction is also narrowed at the same time. Since the undetectable area in the direction may expand, it was not possible to meet the needs sufficiently.

  As other means for satisfying the condition, the design of the cup-shaped casing in the ultrasonic transducer is changed or adjusted so as to obtain a desired coverage, for example, the cross section is rectangular, elliptical, trapezoidal, teardrop shape There is also a method of forming an internal opening that exhibits the like.

JP-A-9-284896

  However, the conventional ultrasonic transducer cannot maintain the required coverage in the horizontal direction and at the same time narrow the coverage in the vertical direction.

  For example, as shown in FIG. 1A, an ultrasonic transducer (1) disclosed in Japanese Patent Laid-Open No. 9-284896 includes a cup-shaped casing (12) and an internal opening (10) formed in the cup-shaped casing (12). The internal opening (10) has two elliptical shapes intersecting each other, and a piezoelectric element (14) is provided at the bottom of the cup-shaped casing (12). Further, as shown in FIG. 1B, when the ultrasonic cover range is −3 dB, it occupies a range of 54 degrees in the horizontal direction and 50 degrees in the vertical direction. By using such an ultrasonic transducer, it is possible to widen the ultrasonic coverage in the horizontal direction and narrow the ultrasonic coverage in the vertical direction to a certain extent. The shape is not as desired.

  Therefore, the present invention has been filed for the purpose of providing a dumbbell-shaped ultrasonic transducer for improving the above-mentioned drawbacks and solving the above-mentioned problems.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an ultrasonic transducer that can detect an obstacle or measure a distance from an object, and has a wide and optimal structure for propagation of ultrasonic waves.

The invention of claim 1 of the present application is an ultrasonic transducer,
There is provided an ultrasonic transducer having a cup-shaped casing having a side wall, wherein an inner cross section of the side wall perpendicular to a central axis has a substantially dumbbell shape.

The invention of claim 2 of the present application is characterized in that the dumbbell-shaped contour is a pair of straight portions formed to face the longitudinal axis of the dumbbell-shaped contour in parallel.
A pair of arc line portions positioned so as to face both ends of the longitudinal axis of the dumbbell-shaped contour,
Both ends of each arc line portion of the dumbbell-shaped contour are connected to the two straight portions via two curved portions, respectively, and each curved portion has one end of one arc line portion and one straight line, respectively. The ultrasonic transducer according to claim 1, wherein the ultrasonic transducer is connected to a portion.

  The invention of claim 3 of the present application is characterized in that the cup-shaped casing further has a bottom portion, and an inner surface of the bottom portion facing the opening of the cup-shaped casing in the bottom portion has a dumbbell shape. An ultrasonic transducer as described.

  According to the invention of claim 4 of the present application, the dumbbell-shaped plane on the inner surface of the bottom portion has two enlarged areas, and at least one enlarged area has one recessed portion defined in the enlarged area. The ultrasonic transducer according to claim 3, wherein the ultrasonic transducer is provided.

  The present invention solves the above-described problems, and can detect the presence of an object or measure the distance to the object, and can suitably perform wide propagation of ultrasonic waves.

It is a plane sectional view of the conventional ultrasonic transducer. FIG. 1B is an ultrasonic cover range diagram in the horizontal direction and the vertical direction of the ultrasonic transducer shown in FIG. 1A. 1 is a perspective view showing a first embodiment of an ultrasonic transducer according to the present invention. FIG. It is a plane sectional view of the ultrasonic transducer shown in FIG. 2A. It is the 2C-2C sectional view taken on the line of the ultrasonic transducer shown to FIG. 2B. It is a figure which shows the cover range of the ultrasonic wave in the horizontal direction and the vertical direction of the ultrasonic transducer shown to FIG. 2A thru | or FIG. It is a perspective view of an ultrasonic transducer concerning the 2nd example of the present invention. It is a plane sectional view of the ultrasonic transducer shown in FIG. 3A. FIG. 3C is a side sectional view of the ultrasonic transducer shown in FIG. 3B taken along line 3C-3C. FIG. 3B is an ultrasonic cover range diagram in the horizontal direction and the vertical direction of the ultrasonic transducer shown in FIGS. 3A to 3C. It is a perspective view of an ultrasonic transducer concerning the 3rd example of the present invention. It is a plane sectional view of the ultrasonic transducer shown in FIG. 4A. It is the 4C-4C line side surface sectional view of the ultrasonic transducer shown in Drawing 4B.

  Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

  2A is a perspective view showing a first embodiment of the ultrasonic transducer according to the present invention, FIG. 2B is a plan sectional view of the ultrasonic transducer shown in FIG. 2A, and FIG. 2C is an ultrasonic wave shown in FIG. 2B. It is the 2C-2C sectional view taken on the line of a transducer.

  As shown in FIGS. 2A to 2C, the ultrasonic transducer (2) of the present invention has a cup-shaped casing (20) and a piezoelectric element (22), and the main components of the ultrasonic transducer (2). The cup-shaped casing (20), which is a structure, has a cup-shaped configuration that has a substantially cylindrical shape.

  The cup-shaped casing (20) is a cup-shaped body having an opening and a bottom (202), and the side wall (200) is a cylindrical body having a constant diameter. For example, the side wall (200) of the cup-shaped casing (20) is not necessarily cylindrical, for example, from the bottom (202) to the opening or from the opening to the bottom. It can be conceived that it may be formed in a tapered shape that gradually becomes thinner as it goes to (202).

  The central axis of the cylindrical configuration in the cup-shaped casing (20) is substantially coincident with the axis of ultrasonic waves to be transmitted and / or received, and the opening is an ultrasonic transducer. The direction is opposite to the transmission direction of (2). The bottom (202) of the cup-shaped casing (20) is a plane substantially perpendicular to the central axis of the cup-shaped casing (20), and the side wall (200) of the cup-shaped casing (20) is the center. Surrounding the shaft, the bottom (202) and the side wall (200) are joined together to form the cup-shaped structure of the cup-shaped casing (20).

  As shown in FIGS. 2A and 2B, the side wall (200) surrounding the space in the cup-shaped casing (20) has a substantially cylindrical outer surface except for the vicinity of the opening, and the interior surrounding the space. When viewed along the central axis, the interior has a dumbbell-shaped contour, and the space communicates with the opening.

  That is, according to the cross section of the side wall (200) in the direction perpendicular to the central axis, the inside thereof has a sealed dumbbell shape.

  As shown in FIG. 2B, when the central axis of the ultrasonic transducer (2) is a symmetric axis, the dumbbell shape inside the side wall (200) is arranged so as to face the longitudinal direction in parallel. There are a pair of straight portions, and two planes (2000) are formed from the pair of straight portions along the central axis.

  In addition, the dumbbell shape inside the side wall (200) has a pair of arc line portions arranged on opposite sides, and the pair of arc line portions respectively have both ends in the longitudinal direction of the dumbbell shape. And each of the dumbbell-shaped contours forms two enlarged portions, and the pair of arcuate line portions extend along the central axis so as to face each other in the side wall (200). Two recessed surfaces (2002) are formed.

  Furthermore, both ends of each arc line portion in the dumbbell shape are connected to straight portions through two curved portions, respectively, and each curved portion has one end of the arc line portion and one straight portion, respectively. And extending along the central axis so as to form two grooves (2002a), and as a whole, four grooves (2002a) are formed by four curved portions.

  The outer bottom surface of the bottom portion (202) of the cup-shaped casing (20) has a substantially disk shape, and as shown in FIG. 2B, the inner bottom surface corresponding to the opening of the cup-shaped casing (20) in the bottom portion (202) is It exhibits a substantially dumbbell-shaped plane, and the piezoelectric element (22) is usually attached to the center of the inner bottom surface.

  FIG. 2D is a diagram showing the ultrasonic coverage in the horizontal and vertical directions of the ultrasonic transducer shown in FIGS. 2A to 2C, and according to the ultrasonic coverage, in the case of −3 dB in the horizontal direction. Occupying a range of 88 degrees (from +44 degrees to -44 degrees) and 40 degrees in the vertical direction, for example, compared with a conventional ultrasonic transducer disclosed by JP-A-9-284896, Since the ultrasonic transducer according to the present invention has a wider horizontal range and a narrower vertical range, the present invention is an improvement over the conventional one. I understand.

  3A is a perspective view of an ultrasonic transducer (3) according to a second embodiment of the present invention, and FIG. 3B is a cross-sectional plan view of the ultrasonic transducer (3) shown in FIG. 3A. These are 3C-3C line side surface sectional drawing of the ultrasonic transducer (3) shown to FIG. 3B.

  As shown in FIGS. 3A to 3C, the ultrasonic transducer (3) has a cup-shaped casing (30) and a piezoelectric element (32), and the cup-shaped casing (30) is substantially cylindrical. It exhibits a cup shape having

  The bottom (302) of the cup-shaped casing (30) is a plane substantially perpendicular to the central axis of the cup-shaped casing (30), and the side wall (300) of the cup-shaped casing (30) is It surrounds the axis.

  The side wall (300) surrounding the space in the cup-shaped casing (30) has a substantially cylindrical outer surface except for the vicinity of the opening, and the inner surface of the side wall (300) is the center. It has a dumbbell-shaped profile along the axis.

  The inside of the side wall (300) has a sealed dumbbell-shaped contour, and the dumbbell-shaped contour is a pair of straight lines formed so as to face the longitudinal axis of the dumbbell-shaped contour. The pair of straight portions extend along the central axis so as to form two planes (3000) facing each other inside the side wall (300).

  The dumbbell-shaped contour of the inner surface of the side wall (300) has a pair of arcuate line portions provided so as to face each other, and each of the pair of arc-lined portions is a longitudinal axis of the dumbbell-shaped contour. The two arcuate line portions are located on opposite sides of the inside of the side wall (300), respectively, and form two enlarged portions in the dumbbell-shaped contour. It extends along the central axis so as to form two recessed surfaces (3002).

  Furthermore, both ends of each arc line part of the dumbbell-shaped contour are connected to a straight line part via a curved part, and each curved line part is connected to one end of the arc line part and one straight line part, respectively. It is connected and extends along the central axis so as to form two grooves (3002a), and as a whole, four grooves (3002a) are formed by four curved portions.

  The outer bottom surface of the bottom portion (302) of the cup-shaped casing (30) has a substantially disk shape, and corresponds to the opening corresponding to the opening of the cup-shaped casing (30) in the bottom portion (302) as shown in FIG. 3B. The bottom surface has a substantially dumbbell-shaped plane, and the piezoelectric element (32) is usually attached to the center of the inner bottom surface.

  The ultrasonic transducer according to the second embodiment shown in FIGS. 3A to 3C and the first embodiment shown in FIGS. 2A to 2C are different in the inner bottom surface of the bottom portion (302).

  As shown in FIG. 3C, which is a cross-sectional side view, the dumbbell-shaped plane of the bottom (302) further has two recesses (3020) defined in two enlarged areas of the dumbbell-shaped plane, The recessed portion (3020) is recessed so as to sandwich the center of the inner bottom surface of the bottom portion (302) and substantially deepens the space of the cup-shaped casing (30) locally.

  FIG. 3D is an ultrasonic cover range diagram in the horizontal direction and the vertical direction of the ultrasonic transducer shown in FIGS. 3A to 3C, and according to the ultrasonic cover range diagram, in the case of −3 dB, it is 90 Occupying a range of degrees and occupying a range of 32 degrees in the vertical direction, when compared with the ultrasonic transducer according to the first embodiment or the conventional ultrasonic transducer, the ultrasonic transducer according to the present invention is Since it has a wider horizontal ultrasonic cover range and a narrower vertical ultrasonic cover range, the ultrasonic transducer (3) according to the present invention can improve the conventional one.

4A to 4C show an ultrasonic transducer (4) according to a third embodiment obtained by modifying the second embodiment shown in FIGS. 3A to 3C.
4A is a perspective view of an ultrasonic transducer according to a third embodiment of the present invention, FIG. 4B is a plan sectional view of the ultrasonic transducer shown in FIG. 4A, and FIG. 4C is shown in FIG. 4B. It is a 4C-4C line side surface sectional view of an ultrasonic transducer.

  The ultrasonic transducer (4) according to the third embodiment shown in FIGS. 4A to 4C is substantially similar to the first and second embodiments, and includes a side wall (400) and a piezoelectric element ( 42) having a similar cup-shaped casing (40), the cup-shaped casing (40) having a flat surface (4000), a recessed surface (4002), and a groove (4002a). The third embodiment differs from the other embodiments at the bottom (402). The bottom (402) has one recess (4020) defined in one enlarged area of a dumbbell-shaped plane, and the recess (4020) is locally connected to the cup-shaped casing (40). ) To deepen the space.

  The present invention can detect the presence of an object or measure the distance to the object, and can suitably perform wide ultrasonic propagation, and thus has industrial applicability.

DESCRIPTION OF SYMBOLS 1 Ultrasonic transducer 10 Internal opening 12 Cup-shaped casing 14 Piezoelectric element 2 Ultrasonic transducer 20 Cup-shaped casing 200 Side wall 2000 Plane 2002 Recessed surface 2002a Groove 202 Bottom part 22 Piezoelectric element 3 Ultrasonic transducer 30 Cup-shaped casing 300 Side wall 3000 Plane 3002 Depressed surface 3002a Groove 302 Bottom 3020 Depressed recess 32 Piezoelectric element 4 Ultrasonic transducer 40 Cup-shaped casing 400 Side wall 4000 Plane 4002 Depressed surface 4002a Groove 402 Bottom 4020 Depressed recess 42 Piezoelectric element

Claims (4)

An ultrasonic transducer,
An ultrasonic transducer having a cup-shaped casing having a side wall, wherein an inner section of the side wall perpendicular to the central axis has a substantially dumbbell shape. The dumbbell-shaped contour includes a pair of straight portions formed to face in parallel with the longitudinal axis of the dumbbell-shaped contour;
A pair of arc line portions positioned so as to face both ends of the longitudinal axis of the dumbbell-shaped contour,
Both ends of each arc line portion of the dumbbell-shaped contour are connected to the two straight portions via two curved portions, respectively, and each curved portion has one end of one arc line portion and one straight line, respectively. The ultrasonic transducer according to claim 1, wherein the ultrasonic transducer is connected to a portion.   The ultrasonic transducer according to claim 1, wherein the cup-shaped casing further has a bottom portion, and an inner surface of the bottom portion facing the opening of the cup-shaped casing has a dumbbell shape.   The dumbbell-shaped plane on the inner surface of the bottom has two enlarged areas, of which at least one enlarged area has one recess defined in the enlarged area. The ultrasonic transducer according to claim 3.

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