CN217007707U

CN217007707U - Metal detection assembly and device thereof

Info

Publication number: CN217007707U
Application number: CN202220438438.8U
Authority: CN
Inventors: 李孝云; 黄杰峰; 侴智
Original assignee: Shenzhen Mileseey Technology Co ltd
Current assignee: Shenzhen Mileseey Technology Co ltd
Priority date: 2022-03-01
Filing date: 2022-03-01
Publication date: 2022-07-19
Anticipated expiration: 2032-03-01

Abstract

The utility model relates to a metal detection assembly and a device thereof, wherein the metal detection assembly comprises: the receiving coil comprises a main coil with a first area and a first auxiliary coil and a second auxiliary coil which are respectively positioned in the first area, and the first auxiliary coil is respectively connected with the main coil and the second auxiliary coil; the transmitting coil is positioned in the first area and provided with a second area, and the area surrounded by the first secondary coil is at least partially positioned in the second area; the control circuit is respectively connected with the transmitting coil, the main coil, the first auxiliary coil and the second auxiliary coil; the transmitting coil is used for generating a first magnetic field under the driving of the control circuit so as to excite the target metal object to generate a second magnetic field; the receiving coil is used for generating induced electromotive force under the action of a second magnetic field; the control circuit is used for generating a detection signal related to the detection condition of the target metal object under the drive of the induced electromotive force. The metal detection assembly and the device thereof have high detection precision on metal.

Description

Metal detection assembly and device thereof

Technical Field

The utility model relates to the technical field of metal detection, in particular to a metal detection assembly and a device thereof.

Background

At present, in the process of upgrading, reforming or maintaining and building a building, cutting or drilling operation is often required at positions such as a wall and a floor, the building of a bearing mechanism such as the wall and the floor in the existing house structure is usually provided with reinforcing structure strength such as reinforcing steel bars, and the accurate positions of objects such as the reinforcing steel bars hidden in the building cannot be known usually when the building faces maintenance and reforming operation, so that how to avoid metal objects such as the reinforcing steel bars hidden in the building becomes a big pain point for the constructor of upgrading, reforming and maintaining the existing building.

In the prior art, the presence of metal objects in a building is detected by using a metal detection device. However, the existing metal detection device is provided with a magnetic rod inside, and the arrangement of the magnetic rod easily causes adverse effects on the detection of the detected metal, thereby reducing the detection accuracy.

SUMMERY OF THE UTILITY MODEL

In view of the above, it is desirable to provide a metal detection assembly and a device thereof, which can solve the problem of low accuracy of metal detection.

The utility model provides a metal detection assembly, comprising:

a receiving coil including a main coil having a first region and first and second sub-coils respectively located within the first region, the first sub-coil being connected with the main coil and the second sub-coil respectively;

the transmitting coil is positioned in the first area and provided with a second area, and the area surrounded by the first secondary coil is at least partially positioned in the second area; and the number of the first and second groups,

a control circuit connected to the transmitting coil, the main coil, the first sub-coil, and the second sub-coil, respectively;

the transmitting coil is used for generating a first magnetic field under the driving of a transmitting electric signal of the control circuit so as to excite a target metal object to generate a second magnetic field; the receiving coil is used for generating induced electromotive force under the action of a second magnetic field of the target metal object; the control circuit is used for generating a detection signal related to the detection condition of the target metal object under the drive of the induced electromotive force.

In one embodiment, according to the metal detection assembly, the second sub-coil comprises p sequentially connected sub-coils, each of the sub-coils comprising a first connection point and a second connection point; the first connection point of the first sub-coil is connected with the first sub-coil, the first connection point of the kth sub-coil is connected with the second connection point of the (k-1) th sub-coil, and the second connection point of the pth sub-coil is connected with the control circuit; wherein k is a natural number, and k is more than 1 and less than or equal to p.

In one embodiment, according to the above metal detection assembly, the main coil includes a first coil main body and a plurality of first leads, the first coil main body is connected with the first sub-coil, and the plurality of first leads are respectively led out from the first coil main body and connected to the control circuit;

the p-th sub-coil comprises a second coil main body and a plurality of second leads, a first connecting point on the second coil main body is connected with a second connecting point of the p-1-th sub-coil, and the plurality of second leads are respectively led out from the second coil main body and connected to the control circuit.

In one embodiment, according to the metal detection assembly described above, the first sub-coil includes a third coil body connected to the main coil and a plurality of third lead wires respectively led out from the third coil body;

and the control circuit is used for connecting the third coil main body with the first connecting point of the first sub-coil through any one third lead wire.

In one embodiment, the number of the sub-coils is two, and the two sub-coils are axially symmetrically arranged around the center of the transmitting coil.

In one embodiment, the number of the sub-coils is at least three, and a plurality of the sub-coils are arranged around the central position of the transmitting coil.

In one embodiment, the area enclosed by the second sub-winding is located outside the second area.

In one embodiment, the area surrounded by the second sub-winding is partially located in the second area.

In one embodiment, the metal detection assembly further comprises a coil former; the transmitting coil and/or the first secondary coil are/is wound on the coil framework.

A metal detection device comprises a shell and the metal detection assembly, wherein the metal detection assembly is arranged on the shell.

In the metal detection assembly and the device thereof, the transmitting coil and the receiving coil are arranged in a matching way, so that a first magnetic field (namely an alternating magnetic field) can be generated by the transmitting coil under the driving of a transmitting electric signal, when metal detection is carried out on a building, when the first magnetic field acts on a target metal object of the building, the first magnetic field can excite the target metal object to generate a second magnetic field (namely a vortex magnetic field), at the moment, the second magnetic field acts on the receiving coil again to enable the receiving coil to generate induced electromotive force, the control circuit generates a detection signal related to the detection condition of the target metal object under the driving of the induced electromotive force, and a basis is provided for determining the detection result of the target metal object according to the detection signal, so that the metal detection function is realized; in the structure, the magnetic bar is not required to be arranged, the interference caused by the detection of the target metal object to influence the metal detection effect is avoided, and the accuracy of the metal detection is effectively ensured.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments or the conventional technologies of the present application, the drawings used in the descriptions of the embodiments or the conventional technologies will be briefly introduced below, it is obvious that the drawings in the following descriptions are only some embodiments of the present application, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

FIG. 1 is a schematic diagram of a metal detection assembly according to one embodiment;

FIG. 2 is a schematic diagram of the structure of a transmit coil and a receive coil of one embodiment;

FIG. 3 is a schematic diagram of the structure of a transmitting coil and a receiving coil of another embodiment;

FIG. 4 is a schematic diagram of the detection principle of the metal detection assembly in the case of no metal according to one embodiment;

FIG. 5 is a schematic diagram of the detection principle of the metal detection assembly in the presence of metal according to one embodiment;

FIG. 6 is a schematic diagram of the detection principle of a metal detection assembly in the absence of metal according to another embodiment;

FIG. 7 is a schematic view of the detection principle of another embodiment of the metal detection assembly in the presence of metal;

FIG. 8 is a graph illustrating a signal strength versus metal position distribution of a metal detection assembly according to an embodiment.

Detailed Description

To facilitate an understanding of the present application, the present application will now be described more fully with reference to the accompanying drawings. Embodiments of the present application are given in the accompanying drawings. This application may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the description of the present application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

It will be understood that, as used herein, the terms "first," "second," and the like may be used herein to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish one element from another.

It is to be understood that "connection" in the following embodiments is to be understood as "electrical connection", "communication connection", and the like if the connected circuits, modules, units, and the like have communication of electrical signals or data with each other.

As used herein, the singular forms "a", "an" and "the" may include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises/comprising," "includes" or "including," etc., specify the presence of stated features, integers, steps, operations, components, parts, or combinations thereof, but do not preclude the presence or addition of one or more other features, integers, steps, operations, components, parts, or combinations thereof. Also, as used in this specification, the term "and/or" includes any and all combinations of the associated listed items.

It is to be understood that the "region" in the following embodiments refers to a spatial range formed by the surrounding of the coil.

As shown in fig. 1-2, a metal detecting device 100 of an embodiment includes a transmitting coil 10, a receiving coil 20, and a control circuit 30. Wherein:

a receiving coil 20 including a main coil 21, a first sub-coil 22, and a second sub-coil 23; the region surrounded by the main coil 21 is a first region 210, and the first sub-coil 22, the second sub-coil 23, and the transmitting coil 10 are respectively located in the first region 210.

It should be noted that the main coil 21, the first sub-coil 22, the second sub-coil 23, and the transmitting coil 10 may all be located on the same plane, or may be partially located on the same plane, or may be located on different planes respectively; when the first sub-coil 22 and the main coil 21 are located on different planes, the projection of the first sub-coil 22 toward the main coil 21 falls completely within the first region 210; in addition, when the second sub-coil 23 or the transmitting coil 10 and the main coil 21 are located on different planes, the principle of the relative projection relationship between the second sub-coil 23 or the transmitting coil 10 and the main coil 21 is the same as that between the first sub-coil 22 and the main coil 21, and the description thereof is omitted.

A transmitting coil 10, wherein the area enclosed by the transmitting coil is a second area 101; here, it should be noted that the transmitting coil 10 and the first sub-coil 22 may be located on the same plane or on different planes, and when the first sub-coil 22 and the transmitting coil 10 are located on different planes, a projection of the area surrounded by the first sub-coil 22 toward the transmitting coil 10 at least partially falls within the second area 101.

It is worth mentioning that the relative projection relationship between the region enclosed by the first secondary coil 22 and the transmitting coil 10 is not limited, for example, in some embodiments, the first secondary coil 22 is disposed outside the transmitting coil 10, and since the area of the region enclosed by the first secondary coil 22 is larger than the area of the region enclosed by the transmitting coil 10, at this time, the projection of the region enclosed by the first secondary coil 22 toward the transmitting coil 10 completely covers the second region 101, so that the first secondary coil 22 is disposed to completely surround the transmitting coil 10.

Of course, in other embodiments (not shown), the first secondary coil is disposed inside the transmitting coil, and since the area of the region surrounded by the first secondary coil is smaller than the area of the region surrounded by the transmitting coil, at this time, the projection of the region surrounded by the first secondary coil toward the transmitting coil is completely located in the second region, so that the transmitting coil is disposed to completely surround the first secondary coil.

And a control circuit 30 connected to the transmitter coil 10, the main coil 21, the first sub-coil 22, and the second sub-coil 23.

Specifically, the transmitting coil 10, the main coil 21, the first sub-coil 22 and the second sub-coil 23 each have a starting end and an ending end; the starting end and the ending end of the transmitting coil 10 are both connected with the control circuit 30, so as to form an electric signal transmitting loop structure, in practical application, the control circuit 30 can input a transmitting electric signal to the coil, and the transmitting electric signal is an alternating current signal; the starting end of the second sub-coil 23 is connected with the control circuit 30, the ending end of the second sub-coil 23 is connected with the starting end of the first sub-coil 22, the ending end of the first sub-coil 22 is connected with the starting end of the main coil 21, and the ending end of the main coil 21 is connected with the control circuit 30, so that an electric signal receiving loop structure is formed, and the receiving coil 20 can generate an electromagnetic induction phenomenon under the action of a vortex magnetic field, so that induced electromotive force is generated.

When the metal detection assembly 100 is used for metal detection, a first magnetic field (i.e. an alternating magnetic field) covering the receiving coil 20 can be formed by the transmitting coil 10 under the driving of the transmitting electric signal of the control circuit 30, when the first magnetic field acts on a target metal object of a building during metal detection of the building, the first magnetic field can excite the interior of the target metal object to generate an induced eddy current, under the drive of the induced eddy current, the target metal object generates a second magnetic field (namely, an eddy magnetic field), and at the moment, the second magnetic field acts on the receiving coil 20, the receiving coil 20 generates an electromagnetic induction phenomenon under the action of the second magnetic field, thereby generating induced electromotive force, the control circuit 30 generates a detection signal associated with the detection condition of the target metal object under the driving of the induced electromotive force, and provides a basis for determining the detection result of the target metal object according to the detection signal; the frequency of the detection signal is the same as that of the emission signal, the phase of the detection signal is determined by the magnetic permeability of the target metal object, and the phases of the detection signals generated under the action of the second magnetic field of the metal with different magnetic permeability are different, so that judgment can be performed according to the amplitude and the phase of the detection signal to determine the existence condition, the position information and the magnetic property of the target metal object, and the metal detection function is realized.

In the metal detection assembly 100, the metal detection function is realized through the matching of the transmitting coil 10 and the receiving coil 20, a magnetic rod is not required to be arranged, the interference caused by the detection of a target metal object is avoided so as to influence the metal detection effect, and the accuracy of metal detection is effectively ensured.

In addition, when the receiving coil 20 is used, the number of turns of the main coil 21, the first sub-coil 22, and the second sub-coil 23 needs to be adjusted to zero the receiving coil 20. Because the distance between the first secondary coil 22 and the transmitting coil 10 is the closest, the adjustment of the number of turns of the first secondary coil 22 has a large influence on the signal amplitude in the loop of the receiving coil 20, and therefore, the coarse adjustment processing can be performed on the zero adjustment of the receiving coil 20 by adjusting the number of turns of the first secondary coil 22; because the distance between the main coil 21 and the transmitting coil 10 is relatively farthest, the number of turns adjustment of the main coil 21 has little influence on the signal amplitude, so that the number of turns of the main coil 21 can be adjusted to perform fine adjustment processing on the zero adjustment of the receiving coil 20 (the zero adjustment precision of the fine adjustment processing is higher than that of the coarse adjustment processing); because the second sub-coil 23 is located between the main coil 21 and the first sub-coil 22, the number of turns adjustment of the second sub-coil 23 on the side away from the center of the transmitting coil 10 has the smallest influence on the signal amplitude, so that the zeroing of the receiving coil 20 can be finely adjusted by adjusting the number of turns of the second sub-coil 23 on the side away from the center of the transmitting coil 10 (the zeroing precision of the fine adjustment is higher than that of the fine adjustment); in practical applications, the number of turns of the main coil 21, the first sub-coil 22, and the second sub-coil 23 is adjusted in a matching manner, so that the receiving coil 20 can obtain a good zero-setting effect quickly.

For the convenience of understanding the specific structure and the operation principle of the metal detecting assembly 100, the following description will be made with reference to fig. 1 to 7, and the connection relationship, the relative position relationship, the shape, the number of turns and the winding direction of the coil, and the current direction of the following structures are not limited to those shown in the drawings, specifically:

it should be noted that the structural form of the second sub-coil is not limited, and the second sub-coil may be a single coil structure or a multi-coil structure formed by a plurality of sub-coils.

As shown in fig. 1-2, for example, in some embodiments, the second sub-coil 23 comprises p sequentially connected sub-coils, each sub-coil comprising a first connection point at its starting end and a second connection point at its ending end; the first connection point of the first sub-coil is connected with the first sub-coil 22, the first connection point of the kth sub-coil is connected with the second connection point of the (k-1) th sub-coil, and the second connection point of the pth sub-coil is connected with the control circuit 30; wherein k is a natural number, and k is more than 1 and less than or equal to p.

For example, in some embodiments, the second sub-coil 23 includes two sub-coils, where p is 2, the two sub-coils are a first sub-coil 2311 and a second sub-coil 2312, where the first and second connection points of the first sub-coil 2311 are E and F, respectively, and the first and second connection points of the second sub-coil 2312 are G and H, respectively; the main coil 21 comprises a connection point A at the starting end and a connection point B at the ending end, and the first sub-coil 22 comprises a connection point C at the starting end and a connection point D at the ending end; the connection point a is connected to the control circuit 30, and the connection relationship of the connection point after the connection point C is: b and C, D and E, F and G, and finally, the second sub-coil 2312 is connected with the control circuit 30 through a connection point H, so that the main coil 21, the first sub-coil 22, the second sub-coil 23 and the control circuit 30 together form an electric signal receiving loop structure.

In some embodiments, the main coil 21 includes a first coil body 211 and a plurality of first lead wires, the first coil body 211 is connected to the first sub-coil 22 through a connection point B, and the plurality of first lead wires are respectively led out from the first coil body 211; the p-th sub-coil includes a second coil body 2313 and a plurality of second leads, a first connection point of which is connected to a second connection point of the p-1-th sub-coil, the plurality of second leads being respectively led out from the second coil body 2313.

It should be noted that the number of the first lead and the second lead is not limited, for example, in an embodiment, the main coil 21 includes a first coil main body 211 formed by winding a plurality of turns of wires, and m first leads (leads a1, a2, A3, … …, Am respectively) led out from different turns of wires at one end of a connection point a of the first coil main body 211, and the m first leads are connected to the control circuit 30 respectively; the second sub-coil 2312 includes a second coil body 2313, and n second lead wires (lead wires H1, H2, H3, … …, Hn) respectively led out from different turns of conductive wires at one end of a connection point H of the second coil body 2313, and the n second lead wires are respectively connected to the control circuit 30.

In some embodiments, the first sub-coil 22 includes a third coil body 221 and a plurality of third lead wires, the third coil body 221 is connected with the main coil 21 through a connection point C, the plurality of third lead wires are respectively led out from the third coil body 221, and the control circuit is configured to connect the third coil body 221 with the first connection point E of the first sub-coil 2311 through any one of the third lead wires.

It should be noted that the number of the third leads is not limited, for example, in an embodiment, the first sub-coil 22 includes a third coil body 221 formed by winding a plurality of turns of a lead wire, and x third leads (leads D1, D2, D3, … …, Dx) led out by different turns of the lead wire respectively, the x third leads are connected to the connection point E of the first sub-coil 2311 through a switch device or a jumper wire respectively, and are connected to the control circuit 30 respectively, and the control circuit 30 controls on/off of the switch device or the jumper wire on any one of the third leads to realize on/off between the different turns of the lead wire on the third coil body 221 and the first connection point E of the first sub-coil 2311.

It should be noted that the control circuit 30 may select any lead of the receiving coil 20 to connect to the internal circuit through a switching device, which includes, but is not limited to, at least one of a mechanical switch, a jumper switch, an analog switch, a multiplexer, and an electronic switch such as a field effect transistor.

It is worth mentioning that the relative position relationship between the second sub-coil 23 and the transmitting coil 10 is not limited, for example, as shown in fig. 1-2, in some embodiments, the area enclosed by the second sub-coil 23 is located in the second area 101, and when the second sub-coil 23 and the transmitting coil 10 are located on different planes, the projection of the area enclosed by the second sub-coil 23 towards the transmitting coil 10 is located in the second area 101; further, at least a part of the projection of the area surrounded by the sub-coils towards the transmitting coil 10 is positioned in the second area 101; specifically, in the present embodiment, both the first sub-coil 2311 and the second sub-coil 2312 are partially located in the second region 101.

Through the arrangement, the second sub-coil 23 and the transmitting coil 10 can be arranged in an overlapping manner, the winding range of the main coil 21 and the second sub-coil 23 is expanded, more turns can be arranged on the main coil 21 and the second sub-coil 23, the signal intensity received by the receiving coil 20 is improved, and the detection distance is increased.

For another example, as shown in fig. 3, in some other embodiments, the area enclosed by the second sub-coil 23a is located outside the second area 101, and when the second sub-coil 23a is located on a different plane from the transmitting coil 10, the projection of the area enclosed by the second sub-coil 23a toward the transmitting coil 10 is located outside the second area 101; furthermore, the projection of the area surrounded by the sub-coils towards the transmitting coil 10 is entirely outside the second area 101; specifically, in the present embodiment, the first sub-coil 2311a and the second coil 2312a are located entirely outside the second region 101.

Through the arrangement, the second sub-coil 23a is not overlapped with the transmitting coil 10, so that a condition is provided for the second sub-coil 23a and the transmitting coil 10 to be integrated on the same plane, the integration degree of the coils is favorably improved, and the miniaturization design of the metal detection device is realized.

The working principle of the structure is as follows:

as shown in fig. 4, when there is no metal in the external environment (e.g., a building), a line calibration process of the coil needs to be performed in advance, and at this time, the polarity of the induced electromotive force induced on the main coil 21 by the transmitting coil 10 is opposite to the polarity of the induced electromotive force induced on the first sub-coil 22 (the "+/-" symbol on the left of the connection point identification character indicates the polarity of the induced electromotive force), so that the induced electromotive forces induced on the main coil 21 and the first sub-coil 22 are cancelled out.

Note that the polarity of the electromotive force induced in the second sub-coil 23 by the transmission coil 10 is related to the size of the area surrounded by the second sub-coil 23 and located in the second region 101.

In some embodiments, as shown in fig. 4, when the area surrounded by the second sub-coil 23 is located in the second area 101, and the winding of the second sub-coil 23 is closer to the projection center of the transmitting coil 10, the area surrounded by the second sub-coil 23 is located in the second area 101, so that the polarity of the electromotive force induced on the second sub-coil 23 by the transmitting coil 10 is the same as the polarity of the electromotive force induced on the main coil 21 by the transmitting coil 23; in other embodiments, as the winding of the second sub-coil 23 is gradually far from the projection center of the transmitting coil 10, the area of the region surrounded by the second sub-coil 23 in the second region 101 is gradually decreased, at this time, the amplitude of the electromotive force induced by the second sub-coil 23 is gradually decreased (because the area in the transmitting coil 10 surrounded by the second sub-coil 23 is gradually decreased, so that the average magnetic field strength is gradually decreased) until it reaches zero, and if the winding of the second sub-coil 23 continues to be far from the projection center of the transmitting coil 10, the amplitude of the electromotive force induced by the second sub-coil 23 is gradually increased in a reverse direction (at this time, the electromotive force induced by the external magnetic field of the surrounding transmitting coil 10 by the second sub-coil 23 is mainly used).

The control circuit 30 selects one of the lead lines D1, D2, D3, … …, Dx and the like of the first sub-coil 22 to be connected with the second sub-coil 23, then selects one of the lead lines H1, H2, H3, … …, Hn and the like and one of the lead lines a1, a2, A3, … …, Am and the like, amplifies the differential signal thereof, and detects the amplitude of the detection signal, which is sequentially marked as V_H1A1、V_H2A1、V_H3A1、V_HnA1、V_H1A2、V_H2A2、V_H3A2、V_HnA2、……、V_HnAmThe minimum amplitude is found from the amplitude information of the detection signal of the mark (the minimum amplitude is close to zero), the corresponding control selection state (commonly called zero adjustment) is obtained, the control selection state is stored in the nonvolatile memory, and when the circuit calibration processing is exited and the metal detection working mode is entered, the control circuit 30 directly reads out the control selection state information from the nonvolatile memory and sets and executes the corresponding control selection.

In contrast, since the first sub-coil 22 is located close to the transmitting coil 10, the magnetic induction intensity of the position where the first sub-coil 22 is located is larger, and since the main coil 21 is located far from the transmitting coil 10, the magnetic induction intensity of the position where the main coil 21 is located is smaller, so that when the line calibration of the coils is completed, the area of the region surrounded by the selected first sub-coil 22 is smaller than the area of the region surrounded by the selected main coil 21.

In addition, because the first secondary coil 22 is close to the transmitting coil 10, the magnetic induction intensity of the position where the first secondary coil 22 is located is high, and the influence of increasing or decreasing the number of turns of the coil on the signal amplitude during the zero adjustment is large; since the main coil 21 is far away from the transmitting coil 10, the influence of increasing or decreasing the number of turns of the coil on the signal amplitude during the time-adjusting is small; because the winding of the second sub-coil 23 far away from the projection center of the transmitting coil 10 is far away from the center of the transmitting coil 10, and the area of the region surrounded by the sub-coils of the second sub-coil 23 is small, the influence of increasing or decreasing the number of turns of the coil on the signal amplitude during the zero adjustment is minimal; and a good zero setting effect can be quickly obtained by adjusting the turns of the main coil 21, the first auxiliary coil 22 and the second auxiliary coil 23 in a matching manner.

As shown in fig. 5, in the metal detection operation mode, a first magnetic field is generated under the driving of the transmission signal of the transmission coil 10, the metal to be detected (i.e., the target metal object) generates a vortex magnetic field under the action of the first magnetic field, and the receiving coil 20 induces the vortex magnetic field to generate an induced electromotive force, at this time, the induced electromotive force of the first sub-coil 22 has a polarity opposite to that of the main coil 21, and the induced electromotive force of the second sub-coil 23 has a polarity identical to that of the main coil 21. Since the area of the region surrounded by the main coil 21 is larger than the area of the region surrounded by the first sub-coil 22, the induced electromotive force of the main coil 21 is larger than the induced electromotive force of the first sub-coil 22, and at this time, the induced electromotive force polarity of the second sub-coil 23 is the same as the induced electromotive force polarity of the main coil 21, so that the induced electromotive force synthesized by the whole receiving coil 20 is not zero as an echo signal (i.e., a detection signal), the frequency of the induced electromotive force is the same as the frequency of a transmission signal, and the phase of the induced electromotive force changes with metal materials with different magnetic conductivities.

After acquiring a vortex magnetic field differential amplification signal through an ADC (analog-to-digital converter) on the circuit board 40 (i.e., an analog-to-digital converter for converting an analog signal into a digital signal), performing DFT (Discrete Fourier Transform) to extract amplitude information and phase information of an echo signal, and when the amplitude signal of the echo signal satisfies a preset threshold value, determining whether a metal object enters a detection range; if the metal object is detected to enter the detection range, detecting the phase of the signal again to judge whether the phase meets the magnetic conductivity range of the metal object; if the condition is met, the magnetic property of the metal object is judged according to the phase value.

Since the size of the echo signal varies with the relative position of the metal object and the receiving antenna, the echo signal becomes stronger when the metal object approaches the receiving coil 20; the echo signal weakens when the metal object is far away from the receiving coil 20; considering that the amplitude and the distance of the echo signal are in a power function relationship, and determining a proportionality coefficient and a power by least square fitting, thereby judging the relative position of the detected object of the detected target by identifying the variation trend of the echo signal.

In other embodiments, as shown in fig. 6, when there is no metal in the external environment (e.g., a building), the operation principle of the structure is substantially the same as that of the structure shown in fig. 4, and the difference between the two is that: when the area enclosed by the second sub-coil 23a is completely outside the second area 101 and the area enclosed by the second sub-coil 23a inside the second area 101 is 0, the polarity of the electromotive force induced on the second sub-coil 23a by the transmitting coil 10 is opposite to the polarity of the electromotive force induced on the main coil 21. In this embodiment, the principle of zeroing is similar to that of the embodiment shown in fig. 4, and will not be described herein again. As shown in fig. 7, in the metal detection operation mode, the polarity of the induced electromotive force of the first sub-coil 22 is opposite to that of the main coil 21, and the polarity of the induced electromotive force of the second sub-coil 23a is the same as that of the main coil 21.

As shown in fig. 8, the relationship curve of the echo signal size varying with the relative position of the measured metal object and the receiving antenna; the user moves the detection device on the surface of the building body, and the accurate position of the metal body to be detected in the building body can be determined according to the position of the maximum point of the amplitude of the echo signal.

It should be noted that the arrangement of the plurality of sub-coils in the second sub-coil 23 is not limited, for example, in some embodiments, as shown in fig. 2 or 3, the second sub-coil 23 includes two sub-coils, and the two sub-coils are axially and symmetrically arranged around the center of the transmitting coil 10, so that it can be effectively ensured that the electromagnetic field emitted by the transmitting coil 10 uniformly covers the two symmetrically distributed sub-coils.

For another example, in some other embodiments (not shown), the second sub-coil includes at least three sub-coils, and the plurality of sub-coils are arranged around the central position of the transmitting coil; this setting is equivalent to placing transmitting coil 10 in the central point of the first region that a plurality of sub-coils enclose, can guarantee effectively that the electromagnetic field that transmitting coil sent covers a plurality of sub-coils uniformly, is favorable to guaranteeing that a plurality of sub-coils homoenergetic produce induced electromotive force under the effect of vortex magnetic field, improves the reliability of detection better, improves the degree of accuracy that detects.

Preferably, in some embodiments, the plurality of sub-coils are arranged symmetrically two by two. For example, in one embodiment, two of the four sub-coils of the second sub-coil are symmetrically distributed on the left and right sides of the transmitting coil with the central position of the transmitting coil as the origin, and the other two sub-coils are symmetrically distributed on the upper and lower sides of the transmitting coil with the central position of the transmitting coil as the origin. Through the arrangement, the symmetry of the plurality of sub-coils is higher, and the reliability and the accuracy of metal detection are improved.

In some embodiments, as shown in fig. 1-2, the center position of the first secondary coil 22 coincides with the center position of the transmitting coil 10, so that the first secondary coil 22 and the transmitting coil 10 are concentrically arranged, and the electromagnetic field generated by the transmitting coil can be better ensured to uniformly cover the first secondary coil 22.

In some embodiments, as shown in fig. 1-2, the metal detection assembly 100 further includes a bobbin 50 and a circuit board 40, the transmission coil 10 and/or the first sub-coil 22 is wound around the bobbin 50, and at least one of the transmission coil 10, the main coil 21 and the first sub-coil 22, and the second sub-coil 23 is printed on the circuit board 40.

For example, in the present embodiment, since the coverage area of the main coil 21 is large, and the coverage areas of the transmitting coil 10 and the sub-coil 22 are relatively small, the main coil 21 is printed and formed on the circuit board 40, thereby avoiding using an oversized skeleton to provide support for the main coil 21, which is not favorable for the miniaturization design of the metal detection assembly 100; in addition, the transmitting coil 10 and the first sub-coil 22 can be wound on the coil skeleton 50 to form a two-in-one coil skeleton 50 structure, so that the assembly of the transmitting coil 10 and the first sub-coil 22 is more convenient; meanwhile, the second sub-coil 23 is printed and molded on the circuit board 40, so that the second sub-coil 23 and the first sub-coil 22 are respectively arranged on different planes, the problem that wiring is difficult due to interference of the windings of the second sub-coil 23 and the first sub-coil 22 is not needed to be considered, more wiring space is provided for the second sub-coil 23, the winding structure of the second sub-coil 23 is facilitated to be simplified, and the adjustability of the number of winding turns of the second sub-coil 23 is improved.

Of course, in other embodiments, the transmitting coil 10 and the first sub-coil 22 may be printed on the circuit board 40 to further improve the molding efficiency and facilitate the light and thin design of the metal detection assembly 100.

It should be noted that the coil shapes of the sub-coils of the transmitting coil 10, the main coil 21, the first sub-coil 22 and the second sub-coil 23 are not limited, and the coil shapes are usually circular or rectangular, but are not limited to circular and rectangular, and may also be adjusted to be elliptical, trapezoidal or other shapes according to the wiring of the circuit board 40 or the structural shape of the bobbin 50, and the details thereof are not repeated herein.

In the present invention, a metal detecting device (not shown) is further provided, which includes a housing and the metal detecting component, wherein the metal detecting component is installed on the housing.

In the structure, the metal detection assembly is arranged, so that the accuracy of metal detection is effectively ensured.

In the description herein, references to "some embodiments," "other embodiments," "desired embodiments," or the like, mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the utility model. In this specification, a schematic description of the above terminology may not necessarily refer to the same embodiment or example.

All possible combinations of the technical features of the above embodiments may not be described for the sake of brevity, but should be considered as within the scope of the present disclosure as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the utility model. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.

Claims

1. A metal detection assembly, comprising:

a control circuit connected to the transmitter coil, the primary coil, the first secondary coil, and the second secondary coil, respectively;

2. A metal detection assembly according to claim 1, wherein the second sub-coil comprises p sequentially connected sub-coils, each sub-coil comprising a first connection point and a second connection point; the first connecting point of the first sub-coil is connected with the first sub-coil, the first connecting point of the kth sub-coil is connected with the second connecting point of the (k-1) th sub-coil, and the second connecting point of the pth sub-coil is connected with the control circuit; wherein k is a natural number, and k is more than 1 and less than or equal to p.

3. The metal detection assembly of claim 2, wherein the primary coil includes a first coil body connected with the first secondary coil, and a plurality of first lead wires respectively led out of the first coil body and connected to the control circuit;

4. A metal detection assembly according to claim 2, wherein the first sub-coil comprises a third coil body connected with the main coil and a plurality of third lead wires respectively led out from the third coil body;

5. A metal detection assembly according to claim 2, wherein the sub-coils comprise two, the two sub-coils being arranged axially symmetrically about the centre of the transmitter coil.

6. A metal detection assembly according to claim 2, wherein the sub-coils comprise at least three, a plurality of which are arranged circumferentially around a central position of the transmitter coil.

7. A metal detection assembly according to any of claims 1 to 6, wherein the area enclosed by the second sub-winding is outside the second area.

8. A metal detection assembly according to any of claims 1 to 6, wherein the part of the area enclosed by the second sub-winding is located within the second area.

9. The metal detection assembly of any one of claims 1-6, further comprising a bobbin; the transmitting coil and/or the first auxiliary coil are wound on the coil framework.

10. A metal detection device comprising a housing and a metal detection assembly as claimed in any one of claims 1 to 9 mounted to the housing.