Metal detection assembly and apparatus therefor

Abstract

The application relates to a metal detection assembly and a device thereof, the metal detection assembly comprising a receiving coil, a transmitting coil and a control circuit, wherein the receiving coil comprises a main coil with a first area and a first sub-coil and a second sub-coil located in the first area respectively, the first sub-coil is connected with the main coil and the second sub-coil respectively; the transmitting coil is located in the first area and has a second area, an area surrounded by the first sub-coil is at least partially located in the second area; the control circuit is connected with 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 the control circuit to excite a target metal object to generate a second magnetic field; the receiving coil is used for generating an induced electromotive force under the action of the second magnetic field; and the control circuit is used for generating a detection signal associated with the detection condition of the target metal object under the driving of the induced electromotive force. The metal detection assembly and the device thereof have high detection precision for metal.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of metal detection, in particular to a metal detection assembly and device thereof. BACKGROUND

[0002] Currently, cutting or drilling operations are often required in wall floor and other positions during building upgrading and maintenance construction. In the current house structure, the load-bearing mechanism of the wall, floor and other structures usually has a built-in steel reinforcement to strengthen the structure strength. When facing maintenance and reconstruction operations, the exact position of the steel and other objects hidden in the building body cannot be known. Therefore, how to avoid the steel and other metal objects hidden in the building body has become a big pain for the current building upgrading and reconstruction maintenance construction personnel.

[0003] In the prior art, a metal detection device is used to detect whether there is a metal object in the building body. However, the existing metal detection device is provided with a magnetic bar inside, which is easy to have an adverse effect on the detection of the measured metal, thereby reducing the detection accuracy. SUMMARY

[0004] Therefore, it is necessary to provide a metal detection assembly and device thereof aiming at the problem of low metal detection accuracy.

[0005] The present application provides a metal detection assembly, comprising:

[0006] a receiving coil comprising a main coil having a first area and a first sub-coil and a second sub-coil located in the first area respectively, the first sub-coil being connected with the main coil and the second sub-coil respectively;

[0007] a transmitting coil located in the first area and having a second area, the area surrounded by the first sub-coil being at least partially located in the second area; and

[0008] a control circuit connected with the transmitting coil, the main coil, the first sub-coil and the second sub-coil respectively;

[0009] wherein the transmitting coil is used to generate a first magnetic field to excite a target metal object to generate a second magnetic field under the driving of a transmitting electrical signal of the control circuit; the receiving coil is used to generate an induced electromotive force under the action of the second magnetic field of the target metal object; and the control circuit is used to generate a detection signal associated with the detection condition of the target metal object under the driving of the induced electromotive force.

[0010] In one of the embodiments, according to the metal detecting assembly as described above, the second sub-coil comprises p sub-coils connected in sequence, each of the sub-coils comprises 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, 1

[0011] In one of the embodiments, according to the metal detecting assembly as described above, the main coil comprises a first coil body and a plurality of first leads, the first coil body is connected with the first sub-coil, and the plurality of first leads are respectively led out from the first coil body and connected to the control circuit.

[0012] The pth sub-coil comprises a second coil body and a plurality of second leads, the first connection point on the second coil body is connected with the second connection point of the (p-1)th sub-coil, and the plurality of second leads are respectively led out from the second coil body and connected to the control circuit.

[0013] In one of the embodiments, according to the metal detecting assembly as described above, the first sub-coil comprises a third coil body and a plurality of third leads, the third coil body is connected with the main coil, and the plurality of third leads are respectively led out from the third coil body.

[0014] The control circuit is configured to connect the third coil body with the first connection point of the first sub-coil through any one of the third leads.

[0015] In one of the embodiments, the sub-coil comprises two, and the two sub-coils are arranged symmetrically around the central axis of the transmitting coil.

[0016] In one of the embodiments, the sub-coil comprises at least three, and the plurality of sub-coils are arranged around the central position of the transmitting coil.

[0017] In one of the embodiments, the area surrounded by the second sub-coil is located outside the second area.

[0018] In one of the embodiments, the area surrounded by the second sub-coil is partially located within the second area.

[0019] In one of the embodiments, the metal detecting assembly further comprises a coil skeleton, and the transmitting coil and / or the first sub-coil is wound on the coil skeleton.

[0020] A metal detecting device, comprising a housing and a metal detecting assembly as described above, wherein the metal detecting assembly is installed in the housing.

[0021] The metal detection assembly and the device thereof have the following advantages. The transmitting coil and the receiving coil are cooperatively arranged, so that the transmitting coil can generate a first magnetic field (i.e., an alternating magnetic field) under the driving of the transmitted electric signal. When the first magnetic field acts on a target metal object of a building during the metal detection of the building, the first magnetic field can excite the target metal object to generate a second magnetic field (i.e., a vortex magnetic field). At this time, the second magnetic field acts on the receiving coil to generate an induced electromotive force in the receiving coil. The control circuit generates a detection signal associated with the detection condition of the target metal object under the driving of the induced electromotive force, thereby providing a basis for determining the detection result of the target metal object according to the detection signal, and thus realizing the metal detection function. In the structure, the magnetic bar is not required to be arranged, so that the metal detection is not disturbed by the target metal object to affect the metal detection effect, and the accuracy of the metal detection is effectively ensured. BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative effort on the basis of these drawings.

[0023] Figure 1 Structure diagram of a metal detection assembly of an embodiment;

[0024] Figure 2 Structure diagram of a transmitting coil and a receiving coil of an embodiment;

[0025] Figure 3 Structure diagram of a transmitting coil and a receiving coil of another embodiment;

[0026] Figure 4 Principle diagram of detection of a metal detection assembly of an embodiment in the case of no metal;

[0027] Figure 5 Principle diagram of detection of a metal detection assembly of an embodiment in the case of metal;

[0028] Figure 6 Principle diagram of detection of a metal detection assembly of another embodiment in the case of no metal;

[0029] Figure 7 Principle diagram of detection of a metal detection assembly of another embodiment in the case of metal;

[0030] Figure 8 Signal strength and metal position distribution curve diagram of a metal detection assembly of an embodiment. Detailed Implementation

[0031] To facilitate understanding of this application, a more complete description will be provided below with reference to the accompanying drawings, which illustrate embodiments of the present application. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that the disclosure of this application will be thorough and complete.

[0032] Unless otherwise defined, 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 is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0033] It is understood that the terms “first,” “second,” etc., used in this application 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.

[0034] It is understood that the term "connection" in the following embodiments should be understood as "electrical connection," "communication connection," etc., if the connected circuits, modules, units, etc., have electrical signal or data transmission with each other.

[0035] When used herein, the singular forms of “a,” “an,” and “the” may also include the plural forms unless the context clearly indicates otherwise. It should also be understood that terms such as “comprising / including” or “having” specify the presence of the stated features, integrals, steps, operations, components, parts, or combinations thereof, but do not preclude the possibility of the presence or addition of one or more other features, integrals, steps, operations, components, parts, or combinations thereof. Meanwhile, the term “and / or” as used in this specification includes any and all combinations of the associated listed items.

[0036] It is understood that in the following embodiments, "region" refers to the spatial range formed by the coil.

[0037] like Figures 1-2 As shown, a metal detection device 100 according to one embodiment includes a transmitting coil 10, a receiving coil 20, and a control circuit 30. Wherein:

[0038] The receiving coil 20 includes a main coil 21, a first auxiliary coil 22, and a second auxiliary coil 23; wherein the area enclosed by the main coil 21 is a first region 210, and the first auxiliary coil 22, the second auxiliary coil 23, and the transmitting coil 10 are located within the first region 210.

[0039] It should be noted that the main coil 21, the first secondary coil 22, the second secondary coil 23 and the transmitting coil 10 can be all located on the same plane, can be partially located on the same plane, or can be located on different planes respectively; when the first secondary coil 22 and the main coil 21 are located on different planes, the projection of the first secondary coil 22 towards the main coil 21 completely falls within the first area 210; in addition, when the second secondary coil 23 or the transmitting coil 10 and the main coil 21 are located on different planes, the relative projection relationship between the second secondary coil 23 or the transmitting coil 10 and the main coil 21 is the same as the principle of the relative projection relationship between the first secondary coil 22 and the main coil 21, and will not be described here.

[0040] The area surrounded by the transmitting coil 10 is the second area 101; and the area surrounded by the first secondary coil 22 is at least partially located within the second area 101; here, it should be noted that the transmitting coil 10 and the first secondary coil 22 can be located on the same plane, or can be located on different planes respectively; and when the first secondary coil 22 and the transmitting coil 10 are located on different planes, the projection of the area surrounded by the first secondary coil 22 towards the transmitting coil 10 is at least partially located within the second area 101.

[0041] It is worth mentioning that the relative projection relationship between the area surrounded 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 placed outside the transmitting coil 10; since the area surrounded by the first secondary coil 22 is larger than the area surrounded by the transmitting coil 10, at this time, the projection of the area surrounded by the first secondary coil 22 towards the transmitting coil 10 completely covers the second area 101, so that the first secondary coil 22 completely surrounds the transmitting coil 10.

[0042] Of course, in other embodiments (not shown), the first secondary coil is placed inside the transmitting coil; since the area surrounded by the first secondary coil is smaller than the area surrounded by the transmitting coil, at this time, the projection of the area surrounded by the first secondary coil towards the transmitting coil is completely located within the second area, so that the transmitting coil completely surrounds the first secondary coil.

[0043] The control circuit 30 is connected with the transmitting coil 10, the main coil 21, the first secondary coil 22 and the second secondary coil 23 respectively.

[0044] Specifically, the transmitting coil 10, the main coil 21, the first auxiliary coil 22 and the second auxiliary coil 23 each have a start end and an end end; the start end and the end end of the transmitting coil 10 are connected with the control circuit 30, thereby forming an electric signal transmitting loop structure; in actual 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 start end of the second auxiliary coil 23 is connected with the control circuit 30, the end end of the second auxiliary coil 23 is connected with the start end of the first auxiliary coil 22, the end end of the first auxiliary coil 22 is connected with the start end of the main coil 21, and the end end of the main coil 21 is connected with the control circuit 30, thereby forming an electric signal receiving loop structure, and the receiving coil 20 can generate electromagnetic induction phenomenon under the action of the vortex magnetic field, thereby generating an induced electromotive force.

[0045] In the metal detection using the metal detection assembly 100, the transmitting coil 10 can form a first magnetic field (i.e. an alternating magnetic field) covering the receiving coil 20 under the driving of the transmitting electric signal of the control circuit 30; when the first magnetic field acts on the target metal object of the building, the first magnetic field can excite the induced vortex current in the target metal object, and the target metal object can generate a second magnetic field (i.e. a vortex magnetic field) under the driving of the induced vortex current; at this time, the second magnetic field acts on the receiving coil 20, the receiving coil 20 generates electromagnetic induction phenomenon under the action of the second magnetic field, thereby generating an induced electromotive force; the control circuit 30 generates a detection signal associated with the detection of the target metal object under the driving of the induced electromotive force, thereby providing a basis for determining the detection result of the target metal object according to the detection signal; since the frequency of the detection signal is the same as that of the transmitting signal, and the phase of the detection signal is determined by the magnetic permeability of the target metal object, the phase of the detection signal generated under the action of the second magnetic field of the metal with different magnetic permeabilities is also different, so that the existence, position information and magnetic property of the target metal object can be determined according to the amplitude and phase of the detection signal, thereby realizing the metal detection function.

[0046] In the metal detection assembly 100, the metal detection function is realized by the cooperation of the transmitting coil 10 and the receiving coil 20, without the need to set a magnetic rod, thereby avoiding the interference in the detection of the target metal object to affect the metal detection effect, and effectively ensuring the accuracy of the metal detection.

[0047] In addition, the receiving coil 20 needs to be adjusted in the number of turns of the main coil 21, the first secondary coil 22 and the second secondary coil 23 to achieve the zero adjustment of the receiving coil 20 in use. Among them, since the distance between the first secondary coil 22 and the transmitting coil 10 is the closest, the number of turns of the first secondary coil 22 has a greater impact on the signal amplitude in the receiving coil 20 loop, so the zero adjustment of the receiving coil 20 can be coarsely adjusted by adjusting the number of turns of the first secondary coil 22; and since the distance between the main coil 21 and the transmitting coil 10 is relatively the farthest, the number of turns of the main coil 21 has a smaller impact on the signal amplitude, so the zero adjustment of the receiving coil 20 can be finely adjusted by adjusting the number of turns of the main coil 21 (the zero adjustment accuracy of the fine adjustment is higher than that of the coarse adjustment); since the second secondary coil 23 is located between the main coil 21 and the first secondary coil 22, the number of turns of the second secondary coil 23 away from the center position of the transmitting coil 10 has the smallest impact on the signal amplitude, so the zero adjustment of the receiving coil 20 can be finely adjusted by adjusting the number of turns of the second secondary coil 23 away from the center position of the transmitting coil 10 (the zero adjustment accuracy of the fine adjustment is higher than that of the fine adjustment); in actual application, the number of turns of the main coil 21, the first secondary coil 22 and the second secondary coil 23 can be adjusted to make the receiving coil 20 quickly get a better zero adjustment effect.

[0048] In order to facilitate the understanding of the specific structure of the metal detection assembly 100 and its working principle, the following will be explained in detail in combination with the drawings. Figures 1-7 The connection relationship, relative position relationship, shape, number of turns and winding direction of the coils, and current direction in the following content are not limited to the drawings, and the specific:

[0049] It is worth mentioning that the structure of the second secondary coil is not limited, which can be a single coil structure or a multi-coil structure composed of multiple sub-coils.

[0050] As Figures 1-2 shown, for example, in some embodiments, the second secondary coil 23 includes p sub-coils connected in sequence, each sub-coil includes a first connection point at the starting end and a second connection point at the ending end; the first connection point of the first sub-coil is connected with the first secondary 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, 1 < k ≤ p.

[0051] For example, in some embodiments, the second sub-coil 23 includes two sub-coils, i.e. p = 2, and the two sub-coils are a first sub-coil 2311 and a second sub-coil 2312, wherein 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 includes a connection point A at the starting end and a connection point B at the ending end, and the first sub-coil 22 includes a connection point C at the starting end and a connection point D at the ending end; wherein the connection point A is connected to the control circuit 30, and the connection relationship of the connection points after the connection point C is: B and C are connected, D and E are connected, F and G are connected, and finally, the second sub-coil 2312 is connected to the control circuit 30 through the 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 electrical signal receiving loop structure.

[0052] In some embodiments, the main coil 21 includes a first coil body 211 and a plurality of first leads, the first coil body 211 is connected to the first sub-coil 22 through the connection point B, and the plurality of first leads are respectively led out from the first coil body 211; the pthsub-coil includes a second coil body 2313 and a plurality of second leads, the first connection point of the plurality of second leads is connected to the second connection point of the (p-1)thsub-coil, and the plurality of second leads are respectively led out from the second coil body 2313.

[0053] It is worth mentioning that the number of first leads and second leads is not limited, for example, in an embodiment, the main coil 21 includes a first coil body 211 formed by a plurality of turns of wire, and m first leads (respectively, leads A1, A2, A3, …, Am) are respectively led out from the connection point A of the first coil body 211 by different turns of wire, and the m first leads are respectively connected to the control circuit 30; the second sub-coil 2312 includes a second coil body 2313 and n second leads (respectively, leads H1, H2, H3, …, Hn) are respectively led out from the connection point H of the second coil body 2313 by different turns of wire, and the n second leads are respectively connected to the control circuit 30.

[0054] In some embodiments, the first sub-coil 22 includes a third coil body 221 and a plurality of third leads, the third coil body 221 is connected to the main coil 21 through the connection point C, and the plurality of third leads are respectively led out from the third coil body 221, and the control circuit is used to connect the third coil body 221 and the first connection point E of the first sub-coil 2311 through any one of the third leads.

[0055] It is worth mentioning that the number of third leads is not limited, for example, in an embodiment, the first sub-coil 22 includes a third coil body 221 formed by a plurality of turns of wire and x third leads (D1, D2, D3, …, Dx respectively) respectively led out by different turns of wire, the x third leads are respectively connected to the connection point E of the first sub-coil 2311 through a switch device or a jumper, and are respectively connected with the control circuit 30, and the control circuit 30 controls the on-off of the switch device or the jumper on any third lead to realize the on-off between different turns of wire on the third coil body 221 and the first connection point E of the first sub-coil 2311.

[0056] It should be noted that the control circuit 30 can select any lead of the receiving coil 20 to be connected to the internal circuit through a switch 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.

[0057] 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 Figures 1-2 some embodiments, the area surrounded 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 in different planes, the projection of the area surrounded by the second sub-coil 23 towards the transmitting coil 10 is located in the second area 101; further, the projection of the area surrounded by each sub-coil towards the transmitting coil 10 is at least partially located in the second area 101; specifically, in this embodiment, the first sub-coil 2311 and the second sub-coil 2312 are both partially located in the second area 101.

[0058] Through the above arrangement, the second sub-coil 23 and the transmitting coil 10 can be overlapped, which expands the winding range of the main coil 21 and the receiving second sub-coil 23, so that the main coil 21 and the receiving second sub-coil 23 can be provided with more turns, which is beneficial to improve the signal strength of the receiving coil 20, thereby increasing the detection distance.

[0059] For example, as shown in Figure 3 some other embodiments, the area surrounded by the second sub-coil 23a is located outside the second area 101, and when the second sub-coil 23a and the transmitting coil 10 are located in different planes, the projection of the area surrounded by the second sub-coil 23a towards the transmitting coil 10 is located outside the second area 101; further, the projection of the area surrounded by each sub-coil towards the transmitting coil 10 is all located outside the second area 101; specifically, in this embodiment, the first sub-coil 2311a and the second sub-coil 2312a are completely located outside the second area 101.

[0060] Through the above setting, the second sub-coil 23a and the transmitting coil 10 do not overlap, which provides conditions for the integration of the second sub-coil 23a and the transmitting coil 10 in the same plane, and is conducive to improving the integration degree of the coil, thereby realizing the miniaturization design of the metal detection device.

[0061] The working principle of the above structure is as follows:

[0062] As shown in Figure 4 , when there is no metal in the external environment (such as a building), a coil line calibration process needs to be performed in advance. At this time, the induced electromotive force polarity of the transmitting coil 10 on the main coil 21 is opposite to the induced electromotive force polarity on the first sub-coil 22 (the “+ / -” symbol on the left of the connection point mark indicates the polarity of the induced electromotive force), so that the induced electromotive forces on the main coil 21 and the first sub-coil 22 cancel each other out.

[0063] It should be noted that the polarity of the electromotive force induced by the transmitting coil 10 on the second sub-coil 23 is related to the size of the area of the region surrounded by the second sub-coil 23 located in the second region 101.

[0064] In some embodiments, as shown in Figure 4 , when the region surrounded by the second sub-coil 23 is located in the second region 101, and the winding of the second sub-coil 23 is relatively close to the projection center of the transmitting coil 10, the area of the region surrounded by the second sub-coil 23 located in the second region 101 is relatively large, so that the polarity of the electromotive force induced by the transmitting coil 10 on the second sub-coil 23 is the same as the polarity of the electromotive force induced by the transmitting coil 10 on the main coil 21. In other embodiments, as the winding of the second sub-coil 23 gradually moves away from the projection center of the transmitting coil 10, the area of the region surrounded by the second sub-coil 23 located in the second region 101 gradually decreases, at this time, the amplitude of the electromotive force induced by the second sub-coil 23 gradually decreases (because the area enclosed by the second sub-coil 23 in the transmitting coil 10 gradually decreases, so that the average magnetic field strength gradually decreases) until it is zero, and if the winding of the second sub-coil 23 continues to move away from the projection center of the transmitting coil 10, the amplitude of the electromotive force induced by the second sub-coil 23 gradually reverses and increases (at this time, the electromotive force induced by the second sub-coil 23 is mainly the electromotive force induced by the magnetic field outside the transmitting coil 10).

[0065] The control circuit 30 first selects one of the D1, D2, D3, …, Dx lead-out lines of the first sub-coil 22 connected to the second sub-coil 23, and then selects one of the H1, H2, H3, …, Hn lead-out lines and one of the A1, A2, A3, …, Am lead-out lines, respectively, and detects the amplitude of the detection signal after amplifying the differential signal, which is sequentially marked as V H1A1 , V H2A1 , V H3A1 , VHnA1 , V H1A2 , V H2A2 , V H3A2 , V HnA2 , …, V HnAm From the marked detection signal amplitude information, the minimum amplitude (which is close to zero) is found, the corresponding control selection state (commonly known as zero setting) is obtained, and this control selection state is saved in the non-volatile memory. When the line calibration process is exited and the metal detection working mode is entered, the control circuit 30 directly reads the control selection state information from the non-volatile memory and sets the corresponding control selection.

[0066] In comparison, since the first secondary coil 22 is close to the transmitting coil 10, the magnetic induction intensity at the position of the first secondary coil 22 is relatively large, and since the main coil 21 is far away from the transmitting coil 10, the magnetic induction intensity at the position of the main coil 21 is relatively small. Therefore, when the line calibration of the coils is completed, the area of the region surrounded by the selected first secondary coil 22 is smaller than the area of the region surrounded by the selected main coil 21.

[0067] In addition, since the first secondary coil 22 is close to the transmitting coil 10, the magnetic induction intensity at the position of the first secondary coil 22 is relatively large, and increasing or decreasing the number of turns of the coil has a relatively large impact on the signal amplitude during the aforementioned zero setting. Since the main coil 21 is far away from the transmitting coil 10, increasing or decreasing the number of turns of the coil has a relatively small impact on the signal amplitude during the aforementioned zero setting. Since the side of the second secondary coil 23 that is 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 each sub-coil of the second secondary coil 23 is small, increasing or decreasing the number of turns of the coil has the smallest impact on the signal amplitude during the aforementioned zero setting. By adjusting the number of turns of the main coil 21, the first secondary coil 22, and the second secondary coil 23, a good zero setting effect can be quickly obtained.

[0068] As Figure 5As shown, in the metal detection mode, the first magnetic field is generated under the driving of the transmitting signal of the transmitting coil 10, and the measured metal (i.e. the target metal object) generates the vortex magnetic field under the action of the first magnetic field. The receiving coil 20 induces the induced electromotive force of the vortex magnetic field. At this time, the induced electromotive force of the first secondary coil 22 is opposite to the induced electromotive force of the main coil 21, while the induced electromotive force of the second secondary coil 23 is the same as the induced electromotive force 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 secondary coil 22, the induced electromotive force of the main coil 21 is larger than the induced electromotive force of the first secondary coil 22. In addition, at this time, the polarity of the induced electromotive force of the second secondary coil 23 is the same as the polarity of the induced electromotive force of the main coil 21. Therefore, the induced electromotive force of the receiving coil 20 as a whole is not zero, and the frequency of the echo signal (i.e. the detection signal) is the same as the frequency of the transmitting signal, and the phase changes with different magnetic permeability metal materials.

[0069] The vortex magnetic field differential amplification signal is collected by the ADC (i.e. analog-to-digital converter, used for converting analog signals into digital signals) on the circuit board 40, and then DFT (Discrete Fourier Transform) is performed to extract the amplitude information and phase information of the echo signal. When the amplitude signal of the echo signal meets the preset threshold value, it can be judged whether there is a metal object entering the detection range. If a metal object is detected to enter the detection range, the phase of the detection signal is detected to determine whether the phase meets the magnetic permeability range of the metal object. If the condition is met, the magnetic property of the metal object is determined according to the phase value.

[0070] Since the size of the echo signal changes with the relative position of the metal object and the receiving antenna, when the metal object is close to the receiving coil 20, the echo signal becomes stronger; when the metal object is far away from the receiving coil 20, the echo signal becomes weaker. Since the echo signal amplitude and the distance have a power function relationship, the proportion coefficient and the power are determined by the least square fitting, and thus the relative position of the measured target detection object is determined by identifying the change trend of the echo signal.

[0071] In other embodiments, as shown in Figure 6 When there is no metal in the external environment (such as a building), the working principle of the structure is basically the same as that of the structure shown in the above Figure 4 The difference between the two is that when the area surrounded by the second secondary coil 23a is completely located outside the second area 101, the area surrounded by the second secondary coil 23a in the second area 101 is 0, which makes the polarity of the electromotive force induced by the transmitting coil 10 on the second secondary coil 23a opposite to the polarity of the electromotive force induced by the transmitting coil 10 on the main coil 21. In this embodiment, the principle of zero adjustment is similar to that of the above-mentioned embodiment shown in Figure 4 , and will not be described here.Figure 7 As shown, in the metal detection mode, the induced electromotive force of the first sub-coil 22 is opposite to that of the main coil 21, while the induced electromotive force of the second sub-coil 23a is the same as that of the main coil 21. The working principle of the structure is basically the same as that of the above-mentioned Figure 5 The working principle of the structure shown is basically the same, and therefore will not be expanded here.

[0072] As shown in the figure, the relationship curve of the echo signal size changing 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, and according to the position where the amplitude of the echo signal reaches the maximum point, the accurate position of the measured metal object in the building can be determined. Figure 8 As shown, the relationship curve of the echo signal size changing 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, and according to the position where the amplitude of the echo signal reaches the maximum point, the accurate position of the measured metal object in the building can be determined.

[0073] It is worth mentioning 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 Figure 2 or 3, the second sub-coil 23 includes two sub-coils, which are arranged symmetrically around the center axis of the transmitting coil 10, which can effectively ensure that the electromagnetic field emitted by the transmitting coil 10 uniformly covers the two symmetrically distributed sub-coils.

[0074] For another example, in some other embodiments (not shown), the second sub-coil includes at least three sub-coils, which are arranged around the center position of the transmitting coil; this setting is equivalent to placing the transmitting coil 10 at the center position of the first area surrounded by the plurality of sub-coils, which can effectively ensure that the electromagnetic field emitted by the transmitting coil uniformly covers the plurality of sub-coils, which is conducive to ensuring that the plurality of sub-coils can all generate induced electromotive force under the action of the vortex magnetic field, and better improving the reliability of detection and improving the accuracy of detection.

[0075] More preferably, in some embodiments, the plurality of sub-coils are arranged symmetrically in pairs. For example, in one embodiment, the four sub-coils of the second sub-coil, two of which are symmetrically distributed on the left and right sides of the transmitting coil with the center position of the transmitting coil as the origin, and the other two are symmetrically distributed on the upper and lower sides of the transmitting coil with the center position of the transmitting coil as the origin. Through the above-mentioned setting, the symmetry of the plurality of sub-coils is higher, which is conducive to improving the reliability and accuracy of metal detection.

[0076] In some embodiments, as shown in Figures 1-2 the center position of the first sub-coil 22 coincides with the center position of the transmitting coil 10, so that the first sub-coil 22 and the transmitting coil 10 are concentrically arranged, which can better ensure that the electromagnetic field generated by the transmitting coil uniformly covers the first sub-coil 22.

[0077] In some embodiments, as shown in Figures 1-2As shown, the metal detecting assembly 100 further comprises a coil former 50 and a circuit board 40, the transmitting coil 10 and / or the first auxiliary coil 22 are wound around the coil former 50, and at least one of the transmitting coil 10, the main coil 21 and the first auxiliary coil 22 and the second auxiliary coil 23 are printed on the circuit board 40.

[0078] For example, in the present embodiment, since the main coil 21 has a large coverage area, and the transmitting coil 10 and the auxiliary coil 22 have relatively small coverage areas, the main coil 21 is printed on the circuit board 40, which avoids using a large-size coil former to support the main coil 21, thereby facilitating the miniaturization design of the metal detecting assembly 100; in addition, the transmitting coil 10 and the first auxiliary coil 22 can be wound on the coil former 50 to form a two-in-one coil former 50 structure, which facilitates the assembly of the transmitting coil 10 and the first auxiliary coil 22; meanwhile, the second auxiliary coil 23 is also printed on the circuit board 40, so that the second auxiliary coil 23 and the first auxiliary coil 22 are arranged on different planes, and the problem of wiring difficulty caused by the interference between the winding of the second auxiliary coil 23 and the first auxiliary coil 22 is avoided, thereby providing more wiring space for the second auxiliary coil 23, facilitating the simplification of the winding structure of the second auxiliary coil 23, and improving the adjustability of the number of turns of the second auxiliary coil 23.

[0079] Of course, in other embodiments, in order to further improve the molding efficiency and facilitate the lightweight design of the metal detecting assembly 100, the transmitting coil 10 and the first auxiliary coil 22 can also be printed on the circuit board 40.

[0080] It should be noted that the coil shape of the sub-coils of the transmitting coil 10, the main coil 21, the first auxiliary coil 22 and the second auxiliary coil 23 is not limited, and the coil shape is usually circular or rectangular, but is not limited to circular and rectangular, and can be adaptively adjusted to be elliptical, trapezoidal or other shapes according to the wiring of the circuit board 40 or the structural shape of the coil former 50, which will not be described one by one here.

[0081] In the present application, a metal detecting device (not shown) is also provided, which comprises a housing and the metal detecting assembly described above, and the metal detecting assembly is arranged in the housing.

[0082] In the above structure, the metal detecting assembly is arranged, which effectively ensures the accuracy of metal detection.

[0083] In the description of the present specification, the description of the terms "some embodiments", "other embodiments", "ideal embodiments" and the like means that the specific features, structures, materials or characteristics described in conjunction with the embodiments or examples are contained in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example.

[0084] Any combination of the technical features in the above-described embodiments can be made, and for the sake of brevity, not all possible combinations are described, however, as long as there is no conflict, any combination of the technical features should be considered within the scope of the present disclosure.

[0085] The above-described embodiments only express several implementation manners of the present application, and the description is relatively specific and detailed, but it should not be understood as a limitation on the scope of the patent. It should be pointed out that for ordinary skilled persons in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are within the scope of protection of the present application. Therefore, the scope of protection of the patent of the present application should be subject to the appended claims.

Claims

1. A metal detection component, characterized in that, include: The receiving coil includes a main coil having a first region and a first sub-coil and a second sub-coil located respectively within the first region, wherein the first sub-coil is connected to the main coil and the second sub-coil respectively. A transmitting coil is located within the first region and has a second region, wherein the region enclosed by the first sub-coil is at least partially located within the second region; as well as, The control circuit is connected to the transmitting coil, the main coil, the first auxiliary coil, and the second auxiliary coil, respectively. The transmitting coil is used to generate a first magnetic field under the drive of the transmitting electrical signal of the control circuit to excite the target metal object to generate a second magnetic field; the receiving coil is used to generate an induced electromotive force under the action of the second magnetic field of the target metal object; and the control circuit is used to generate a detection signal associated with the detection status of the target metal object under the drive of the induced electromotive force. When the receiving coil is in use, the number of turns of the first auxiliary coil needs to be adjusted for coarse zeroing, the number of turns of the main coil needs to be adjusted for fine zeroing, and the number of turns of the second auxiliary coil on the side furthest from the center of the transmitting coil needs to be adjusted for micro-zeroing, so as to achieve zeroing of the receiving coil. The zeroing accuracy of the fine adjustment is higher than that of the coarse adjustment, and the zeroing accuracy of the micro-adjustment is higher than that of the fine adjustment.

2. The metal detection component according to claim 1, characterized in that, The second sub-coil includes p sequentially connected sub-coils, each sub-coil including a first connection point and a second connection point; the first connection point of the first sub-coil is connected to the first sub-coil, the first connection point of the k-th sub-coil is connected to the second connection point of the (k-1)-th sub-coil, and the second connection point of the p-th sub-coil is connected to the control circuit; where k is a natural number, 1 < k ≤ p.

3. The metal detection component according to claim 2, characterized in that, The main coil includes a first coil body and a plurality of first leads. The first coil body is connected to the first auxiliary coil, and the plurality of first leads are respectively led out from the first coil body and connected to the control circuit. The p-th sub-coil includes a second coil body and a plurality of second leads. The first connection point on the second coil body is connected to the second connection point of the (p-1)-th sub-coil. The plurality of second leads are respectively led out from the second coil body and connected to the control circuit.

4. The metal detection component according to claim 2, characterized in that, The first secondary coil includes a third coil body and a plurality of third leads. The third coil body is connected to the main coil, and the plurality of third leads are respectively led out from the third coil body. The control circuit is used to connect the third coil body to the first connection point of the first sub-coil via any one of the third leads.

5. The metal detection component according to claim 2, characterized in that, The sub-coil comprises two sub-coils, which are symmetrically arranged about the central axis of the transmitting coil.

6. The metal detection component according to claim 2, characterized in that, The sub-coil includes at least three, and the plurality of the sub-coils are arranged around the center position of the transmitting coil.

7. The metal detection assembly according to any one of claims 1-6, characterized in that, The area enclosed by the second secondary coil is located outside the second region.

8. The metal detection assembly according to any one of claims 1-6, characterized in that, The area enclosed by the second secondary coil is partially located within the second area.

9. The metal detection assembly according to any one of claims 1-6, characterized in that, The metal detection assembly further includes a coil frame; the transmitting coil and / or the first auxiliary coil are wound around the coil frame.

10. A metal detection device, characterized in that, It includes a housing and a metal detection component as described in any one of claims 1-9, wherein the metal detection component is mounted on the housing.

Images