Sonar with damping structure

Abstract

The present disclosure relates to a sonar device (1) for detection of underwater objects. The sonar device comprises a body element (2) having a cavity. A piezo electric element (3) is comprised within the cavity. A resin filling (6) of the cavity protects the piezo electric element (3) from water at underwater operation. The sonar device further comprises a holder (4) adapted to hold the piezo electric element (3). The holder (4) is arranged to centre and hold the piezo electric element (3) within said body element (2). The holder (4) comprises in its structure a plurality of damping structures (5). A method of manufacturing holder and a sonar device is also disclosed.

Claims

1. Sonar device (1) for detection of underwater objects, said sonar device comprising: a body element (2) having a cavity, a piezo electric element (3) positioned within the cavity and having: (i) a half-spherical shape defining a curved surface of the piezo electric element (3), and (ii) a planar surface defined by a diameter of the piezo electric element (3), a holder (4) having a plurality of damping structures (5) and supporting and centering the piezo electric element (3) within the body element (2), the piezo electric element (3) being positioned in the holder (4) such that the piezo electric element (3) is positioned and spaced apart a distance above a base surface of the body element (2), such that a portion of the holder (4) is positioned below the piezo electric element (3) and intermediate the piezo electric element (3) and the base surface, and such that the curved surface of the piezo electric element (3) is encapsulated by the holder (4), and a resin filling (6) within the cavity in order to protect the piezo electric element (3) from water at underwater operation.

2. Sonar device (1) according to claim 1, wherein the planar surface is exposed relative to the holder (4) and the plurality of damping structures (5) thereof.

3. Sonar device (1) according to claim 1, wherein the damping structures (5) are cavities (5) within the material of the holder (4).

4. Sonar device (1) according to claim 3, wherein the cavities comprise spherical cavities (5).

5. Sonar device (1) according to claim 4, wherein spherical radius (10) of the cavities is comprised in a range of 1/10 - 1/100 of the spherical radius (9) of the piezo electric element (3).

6. Sonar device (1) according to claim 3, wherein each cavity (5) has a volume that is comprised in the range of 1/1000 - 1/1,000,000 of the volume of the piezo electric element (3).

7. Sonar device (1) according to claim 3, wherein the cavities are positioned in a regular pattern in the structure of the holder (4) such that the cavities (5) can provide equal damping from all relevant damping directions.

8. Sonar device (1) according to claim 1, wherein further the holder (4) comprises a further cavity suitable to accommodate electronics (7) for the sonar device (1′) directly within the structure of the holder (4).

9. Sonar device (1) according to claim 1, wherein the holder (4) for the piezoelectric element is made by a reciprocating three-dimensional printing device (8).

10. Sonar device (1) according to claim 1, wherein the holder (4) for the piezoelectric element is made of a resin material, for example urethane, nylon or other resin.

11. Method for manufacturing a holder (4) for a sonar device (1) according to claim 1, said method comprising the steps of: providing a reciprocating three-dimensional printing device; and providing an input to said reciprocating three-dimensional printing device that gives instruction to print a holder for a piezo electric element, wherein the input to the printer comprises an instruction to print at least one cavity in the holder for damping purposes.

12. Method according to claim 11, further comprising the steps of: obtaining the holder, positioning a piezo electric element in said holder, providing a body element into which said holder comprising the piezo electric element is inserted, and providing a resin and filling the body element with said resin and covering at the same time said holder and piezo electric element at the same time.

13. Sonar device (1) according to claim 1, wherein the distance is such that the piezo electric element (3) does not directly contact the base surface of the body element (2).

14. Sonar device (1) according to claim 13, wherein the distance is such that the piezo electric element (3) does not directly contact any surfaces of the body element (2).

Description

BRIEF DESCRIPTION OF THE FIGURES

(1) FIG. 1 discloses a sonar device according to the invention from the side, with a transparent body for better view.

(2) FIG. 2 discloses the sonar device of FIG. 1 from above.

(3) FIG. 3 discloses a sonar device with a half spherical piezo electric element.

(4) FIG. 4 discloses a sonar device with a cavity for electronics within the holder for the piezo electric element.

(5) FIG. 5 discloses a reciprocating three dimensional printing device.

(6) FIG. 6 discloses a method for manufacturing a holder for a sonar device.

(7) FIG. 7 discloses a method for manufacturing a sonar device.

DETAILED DESCRIPTION OF VARIOUS EMBODIMENTS

(8) The present disclosure relates to sonar devices 1 for detection of underwater objects according to FIGS. 1-4.

(9) The sonar device 1 for detection of underwater objects, comprises a body element 2. The body element 2 is the element that forms the outer perimeter of the sonar device 1

(10) The body element may have any shape.

(11) As exemplified by FIG. 2 the body element is disclosed as having a circular cylinder shape. The cylinder shape is suitable for a sonar device as it is essentially uniform in a transversal plane as shown in FIG. 2. Even though the cylindrical shape is preferred, the shape of the sonar device can be spherical, or in other ways regular.

(12) The sonar device 1 comprises a piezo electric element 3. The shape of the piezo electric element 3 is preferably half spherical, as shown in FIGS. 1-4. In FIGS. 1 and 4, the piezo electric element 3 is disclosed with a dashed line, as it is positioned inside the body element 2, and not visible in when the sonar device 1 is in operation. The piezo electric element 3 is preferably made of a ferroelectrics material for example barium titanate or lead zirconate titanate or a piezo ceramic material.

(13) The piezo electric element 3 is held by a holder 4. The holder 4 is positioned concentric with the body element 2 in the lower part of the body element 2. The piezo electric element 3 is positioned in the holder 4. The body element 2 is provided with a resin fill.

(14) The holder 4 is provided with a damping structure 5. This damping structure 5 is disclosed in FIG. 1 as round spherical cavities. The shape of the individual damping structure 5, need not be round or spherical, any suitable shape is thinkable.

(15) The damping structure 5 is provided as a unity with the holder 4. Thus cavities are formed within the material of the holder 4. The holder 4 is preferably manufactured in one piece. The damping structure 5 is preferably provided by manufacturing the holder by means of a reciprocating three dimensional printing device 8, see FIG. 5.

(16) The individual damping structure 5 as made up from the cavities 5 has a volume that is comprised in the range of 1/1000-1/1000 000 of the volume of the piezo electric element 3.

(17) The individual damping structure 5 can further be made up from spherical cavities preferably having a spherical radius 10 that is 1/10-1/100 of the spherical radius 9 of the piezo electric element 3.

(18) The damping structure 5 is preferably made as a regularly distributed three dimensional pattern. As propagating sound waves under water comes with a much higher velocity than in air, a regular pattern will interfere much less, and in a predictable way to the propagating sounds waves which are to be detected. If a half sphere is used for the piezo electronic equipment damping is regularly distributed on the bowl shape of the half sphere. Listening is preferred to be done from the flat side 11 of the half sphere.

(19) Preferably the sonar device as disclosed in FIGS. 1-4 has a filling of a resin 6.

(20) The resin is preferably a temperature resistant and has the ability prevent water from entering the sonar device 1 and thereby prevent the piezo electric element 3 from being damaged.

(21) The filling of the resin is provided after installation of the piezo electric element 3 and the holder 4. Thereby the piezo electric element 3 is kept in position during the filling, and after filling both the holder 4 and the resin fill can cooperate in order to hold the piezo electric element 3.

(22) As disclosed in FIG. 4, by using a three dimensional printing device 8 for manufacture of the holder 4 it is possible to design the holder so as to incorporate within the holder the electronic equipment 7 that is needed for the operation of the sonar device 1′. Also the wiring of the electronic equipment can be incorporated directly into the structure of the holder 4. It is possible to completely contain the electronic equipment within the structure but also to leave an opening for easy access from outside if needed.

(23) The electronics is arranged to receive signals from the piezoelectric element. The electronics is arranged to obtain a signal indicative of a detected object under water. Further the electronics may be arranged to obtain the sonar signal based on the received piezo electric signals and based on information related to the influence from the holder 4 on the provided piezo electric signal. In short the holder dampens the signal coming from the bottom or sides of FIGS. 1-4, and as no damping structure is provided from the above listening is mainly done in this direction.

(24) The disclosure also relates to a manufacturing method of the holder 4 for the sonar device 1, 1′ of FIGS. 1-4. The method used as for some steps of the manufacturing a three dimensional printing device 8. The manufacturing method as seen in FIG. 6, comprises the steps of: s1. providing a reciprocating three dimensional printing device

(25) In this step s1 a suitable reciprocating three dimensional printing device 8 is provided. The device can be any device however it must be suitable for providing a layer of for example resin that does not interfere with the piezo electric device 3. s2. providing an input to said reciprocating three dimensional printing device that gives instruction to print a holder for a piezo electric element,

(26) wherein the input to the printer comprises instruction to print at least one cavity in the holder for damping purposes.

(27) In this step s2 the design of the damping structure and the outer dimensions of the holder 4 are set. This must of course be adapted to the chosen piezo electric element, its dimensions and the material of it. The damping structure can be freely designed and it is convenient to design complex damping structures which are contained within the structure of the holder 4. The formed cavities 5 provide the important feature for achieving the damping effect needed for the sonar device. By the manufacturing method it is very convenient as discussed above to provide a damping structure in the form of cavities.

(28) Further there is disclosed a method as seen in FIG. 7, of manufacturing a sonar device according to the above, comprising the steps of: s3. obtaining a holder according to the method above and s4 positioning a piezo electric element in said holder.

(29) Step s3 of obtaining a holder provides for having a holder before steps s5 and s6.The piezo electric element needs to be positioned at a certain position and not move around as the sonar device is finished, thus it is an advantage to have the holder to hold the piezo electric element before going to step s5 and s6.

(30) The method of manufacturing a sonar device further comprises a step of s5. providing a body element into which said holder comprising the piezo electric element is inserted,

(31) By inserting the piezo electric element before introducing the package of piezo electric element and the holder to the body element, the holder can also guide the insertion to the body element, and also protect the piezo electric element during the insertion.

(32) The method of manufacturing a sonar device further comprises a step of s6. providing a resin and filling the body element with said resin and covering at the same time said holder and piezo electric element at the same time.

(33) The resin filling 6 is important for preventing water to enter into contact with the piezo electric element. The resin filling 6 also additionally gives a stabilizing effect on the piezo electric element in cooperation with the holder 4, thus improving the stability of the complete sonar device 1.

(34) Even if only listening is discussed above it should be understood that the sonar can also be active and send out sound waves that are then detected as an echo after, bouncing on objects.