Printed circuit board spiral coil inductance sensor for strong vibration environment and method

Abstract

The invention relates to the technical field of solenoid coil type inductance sensors for printed circuit board processing, and provides a printed circuit board spiral coil inductance sensor for a strong vibration environment and a method. An inductance coil is composed of a spiral line fixed on a printed circuit board, and the spiral line is of an annular structure; the number of layers of the printed circuit board is an even number greater than or equal to 2; the spiral directions of the spiral lines comprise the clockwise direction and the anticlockwise direction, and the spiral lines of every two adjacent layers of printed circuit boards are opposite in direction and are connected end to end through through holes formed in the printed circuit boards. Different inductance coils are formed through connection of different printed circuit boards, and the inductance sensor is manufactured; the width and the interval of the spiral lines are both larger than 0.08 mm, and the number of layers of the spiral lines can be 64 at most. The spiral line is etched on the printed circuit board by adopting a printed circuit board process, and the spiral line inductor can be ensured to be fixed and reliable under the conditions of vibration and temperature change, so that the spiral line inductor is suitable for an inductance sensor in a vibration environment.

Description

Technical Field

[0001] The invention belongs to the field of sensors, and in particular relates to a printed circuit board spiral coil inductance sensor and method used in a strong vibration environment. Background Art

[0002] In the traditional process, the enameled wire inductive sensors generally need to be fixed with epoxy resin glue or vacuum dipping. In the special case of processing inductive sensors with many turns of coils, thin enameled wires and precision requirements, the quality of the inductive sensors is low and the consistency is poor. If the sensor works under conditions of strong vibration and large temperature changes, there is often relative movement between the enameled wires, generating large magnetic field interference noise, affecting the test. Although the enameled wire process can be further strengthened to solve the problem of fixing the enameled wire, the yield rate is still low, the consistency is poor, and the cost will be high.

[0003] Patent 202223343308.5 - A 10-layer coil printed circuit board, which essentially fixes the enameled wire inductor coil on the printed circuit board. Patent 201922009699.9 - A printed circuit board circuit coil manufacturing tooling, which is essentially a set of tooling structures. Patent 201420108698.4 - A high voltage resistant structure of a mutual inductance coil printed circuit board, which essentially provides a high voltage resistant printed circuit board structure for the mutual inductance coil.

[0004] At present, the existing inductive sensors cannot be well applied to strong vibration environments, and the target sensor cannot be quickly prepared based on the target inductance value. Therefore, there is an urgent need to study an inductive sensor that is easy to manufacture, low in cost, stable in use and can be used in strong vibration environments. Summary of the invention

[0005] In view of the shortcomings of the prior art, in order to solve the practical problem that the traditional process is unstable in coil fixation and prone to magnetic field interference under vibration conditions when winding multi-turn, thin enameled wire coil inductors, the present invention provides a printed circuit board spiral coil inductor sensor and method for strong vibration environments, which has the advantages of low cost, high consistency, and stable reliability.

[0006] To achieve the above object, the present invention discloses the following technical solution:

[0007] On the one hand, the present invention provides a printed circuit board spiral coil inductance sensor for use in a strong vibration environment, wherein the inductance coil is composed of a spiral wire fixed on a printed circuit board, the spiral wire is a circular ring structure, and the number of layers of the printed circuit board is an even number greater than or equal to 2;

[0008] The spiral direction of the spiral line includes a clockwise direction and a counterclockwise direction. The spiral lines of two adjacent layers of printed circuit boards are in opposite directions and are connected end to end through through holes opened on the printed circuit boards. The printed circuit boards are cut or silk-screened according to the direction of the spiral lines. Multiple inductance coils are formed by connecting multiple layers of printed circuit boards to obtain a target inductance sensor.

[0009] The width and spacing of the spiral line are both greater than 0.08 mm;

[0010] Build a total inductance calculation model and select the number of printed circuit board layers based on the target inductance value;

[0011] The total inductance calculation model is:

[0012] L 总 =nL+2L×(K 12 +K 13 +K 14 …+K 1n +K 23 +K 24 +…+K n(n-1) )

[0013] Where L is the single-layer inductance value, K is the inductive coupling coefficient between different layers, and n is the number of printed circuit board layers;

[0014] The single-layer inductance value calculation formula is as follows:

[0015]

[0016] Where, μ0=4π10 -7 is the coefficient, N is the number of turns of a single-layer helix, d max is the maximum helix diameter, d min is the minimum helix diameter;

[0017] The calculation formula of the inductive coupling coefficient between different layers is as follows:

[0018]

[0019] Where N is the number of turns of the spiral wire, X is the distance between the layers of the printed circuit board, and A, B, C, and D are all fitting coefficients.

[0020] Preferably, A=0.184, B=-0.525, C=1.038, and D=1.001.

[0021] Preferably, the number of layers of the printed circuit board is 2-64.

[0022] Preferably, the printed circuit board has a thickness of 2 mm, 2.5 mm or 3 mm.

[0023] Preferably, the helical pitch is 0.1±0.05 mm.

[0024] Preferably, the width of the spiral line is between 0.25 mm and 2.5 mm.

[0025] Preferably, the inductance and the DC impedance of the inductor are adjusted by adjusting the line width, spacing and number of layers of the spiral line.

[0026] Preferably, the spiral line is etched on the printed circuit board.

[0027] Preferably, the inductive sensor can be used alone for inductive distance measurement or a plurality of inductive sensors can be connected in cooperation for use in a magnetic field modulation environment.

[0028] Another aspect of the present invention provides a method for preparing the above-mentioned printed circuit board spiral coil inductance sensor for strong vibration environment, which comprises the following steps:

[0029] S1, etching a spiral line on a printed circuit board, and marking the printed circuit board according to the direction of the spiral line;

[0030] S2. Determine the number of layers of the printed circuit board according to the target inductance value, specifically:

[0031] Build a total inductance calculation model and select the number of printed circuit board layers based on the target inductance value;

[0032] The total inductance calculation model is:

[0033] L 总 =nL+2L×(K 12 +K 13 +K 14 …+K 1n +K 23 +K 24 +…+K n(n-1) )

[0034] Where L is the single-layer inductance value, K is the inductive coupling coefficient between different layers, and n is the number of printed circuit board layers;

[0035] The single-layer inductance value calculation formula is as follows:

[0036]

[0037] Where, μ0=4π10 -7 is the coefficient, N is the number of turns of a single-layer helix, d max is the maximum helix diameter, d min is the minimum helix diameter;

[0038] The calculation formula of the inductive coupling coefficient between different layers is as follows:

[0039]

[0040] Where N is the number of turns of the spiral wire, X is the distance between the layers of the printed circuit board, and A, B, C, and D are all fitting coefficients;

[0041] S3, selecting two printed circuit boards with spiral lines in opposite directions for connection, and connecting the spiral lines of two adjacent printed circuit boards end to end through through holes opened on the printed circuit boards;

[0042] S4. Based on the number of printed circuit board layers determined in step S2, the multi-layer printed circuit boards are sequentially connected according to the method of step S3 to obtain multi-layer inductor coils, thereby obtaining a target inductor sensor.

[0043] Compared with the prior art, the present invention has the following beneficial effects:

[0044] (1) The present invention provides a printed circuit board spiral coil inductance sensor for use in a strong vibration environment. The printed circuit board process is used to etch a spiral wire on a printed circuit board to obtain a printed circuit board spiral coil inductance sensor. Under vibration and temperature changes, the spiral wire inductance can be reliably fixed, and the accuracy of the inductance sensor will not be affected by vibration and temperature changes. Therefore, the printed circuit board spiral coil inductance sensor is suitable for various vibration environments.

[0045] (2) The method for preparing an inductive sensor using a printed circuit board adopted in the present invention has low mass production cost, high consistency, and high yield rate. Compared with traditional solutions, it has very high engineering application value.

[0046] (3) The present invention provides a printed circuit board spiral coil inductance sensor for use in a strong vibration environment. When in use, the inductance and the DC impedance of the inductance can be adjusted by adjusting the line width, spacing and number of layers of the spiral line. Compared with the traditional process that requires mold opening and processing of the enameled wire skeleton, the method of the present invention is more flexible to use.

[0047] (4) The present invention provides a calculation model for total inductance, through which the total inductance value under different spiral line widths, spacings and number of layers can be quickly calculated, thereby quickly obtaining the total inductance value. At the same time, the total inductance value can be basically required, and the line width, spacing and number of layers of the spiral line can be adjusted to quickly obtain the target inductance sensor. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 It is a schematic diagram of a first-layer printed circuit board in a multi-layer printed circuit board of the present invention;

[0049] Figure 2 A schematic diagram of adjacent layers of printed circuit boards in a multi-layer printed circuit board of the present invention;

[0050] Figure 3A schematic diagram of the structure size of the printed circuit board inductor of the present invention;

[0051] Figure 4 It is a schematic diagram of the method flow of the present invention. DETAILED DESCRIPTION

[0052] The exemplary embodiments, features and aspects of the present invention will be described in detail below with reference to the accompanying drawings. The same reference numerals in the accompanying drawings represent elements with the same or similar functions. Although various aspects of the embodiments are shown in the accompanying drawings, the drawings are not necessarily drawn to scale unless otherwise specified.

[0053] In one aspect, the present invention provides a printed circuit board spiral coil inductive sensor for use in a strong vibration environment, comprising an inductive coil, such as Figure 1 and Figure 2 As shown, the inductor coil is composed of a spiral line 1 fixed on a printed circuit board, the spiral line 1 is a circular ring structure, and the number of layers of the printed circuit board is an even number greater than or equal to 2; the spiral direction of the spiral line 1 includes a clockwise direction and a counterclockwise direction, and the spiral lines of two adjacent layers of the printed circuit board are in opposite directions and are connected end to end through a through hole 4 opened on the printed circuit board; the number of layers of the printed circuit board 2 is greater than the number of spiral coils. The thickness of the printed circuit board is 2 mm, 2.5 mm or 3 mm. The number of layers of the printed circuit board is 2-60 layers. Figure 1 shows a schematic diagram of the first layer printed circuit board 2, Figure 2 The schematic diagram of adjacent layers of printed circuit boards 3 is shown. A plurality of through holes 4 are provided on the printed circuit boards.

[0054] In practical applications, the spiral direction of the spiral line 1 includes a clockwise direction and a counterclockwise direction. The printed circuit board is cut or marked by silk screen printing according to the direction of the spiral line. Figure 1 and Figure 2 The cutting chamfer 5 is shown in the figure, and a plurality of printed circuit boards are connected to form a plurality of inductance coils to obtain a target inductance sensor. That is, different inductance coils can be obtained by connecting printed circuit boards with different numbers of layers to obtain the required target inductance sensor.

[0055] In a specific embodiment, Figure 3 As shown, the width and pitch of the spiral 1 are both greater than 0.08 mm, and the number of layers of the printed circuit board is an even number greater than or equal to 2, generally 2-64 layers, for example, 10 layers, 12 layers, 24 layers, 48 ​​layers or 64 layers. The optimal choice of the spiral pitch is 0.1±0.05 mm. The optimal choice of the spiral width is between 0.25 mm and 2.5 mm. In a specific embodiment, the spiral pitch is 0.1 mm, the spiral width is 1 mm, and the spiral thickness is 100 mm.

[0056] In a specific application, since the spiral wire is fixed on a printed circuit board, the prepared inductive sensor can be used alone for inductive distance measurement or multiple sensors can be connected together for use in a magnetic field modulation environment.

[0057] In specific use, by adjusting the line width, spacing and number of layers of the spiral line, the inductance and the DC impedance of the inductor can be adjusted. In this embodiment, by constructing a total inductance calculation model, the number of spiral lines is selected based on the target inductance value.

[0058] The total inductance calculation model is:

[0059] L 总 =nL+2L×(K 12 +K 13 +K 14 …+K 1n +K 23 +K 24 +…+K n(n-1) )

[0060] Wherein, L is the single-layer inductance value, K is the inductive coupling coefficient between different layers, and n is the number of printed circuit board layers.

[0061] The single-layer inductance calculation formula is as follows:

[0062]

[0063] Where, μ0=4π10 -7 is the coefficient, N is the number of turns per layer, d max is the maximum diameter of the helix, d min is the minimum diameter of the helix.

[0064] The calculation formula of the inductive coupling coefficient between different layers is as follows:

[0065]

[0066] Where N is the number of turns of the spiral, X is the distance between the layers of the printed circuit board, and A, B, C, and D are all fitting coefficients.

[0067] In a specific embodiment, A=0.184, B=-0.525, C=1.038, and D=1.001.

[0068] Another aspect of the present invention provides a method for preparing the above-mentioned printed circuit board spiral coil inductance sensor for strong vibration environment, such as Figure 4 As shown, it includes the following steps:

[0069] S1. Etching a spiral line on a printed circuit board and marking the printed circuit board according to the direction of the spiral line.

[0070] S2. Determine the number of layers of the printed circuit board according to the target inductance value. This step is specifically as follows:

[0071] Build a total inductance calculation model and select the number of printed circuit board layers based on the target inductance value.

[0072] The total inductance calculation model is:

[0073] L 总 =nL+2L×(K 12 +K 13 +K 14 …+K 1n +K 23 +K 24 +…+K n(n-1) )

[0074] Wherein, L is the single-layer inductance value, K is the inductive coupling coefficient between different layers, and n is the number of printed circuit board layers.

[0075] The single-layer inductance calculation formula is as follows:

[0076]

[0077] Where, μ0=4π10 -7 is the coefficient, N is the number of turns of a single-layer helix, d max is the maximum helix diameter, d min is the minimum helix diameter.

[0078] The calculation formula of the inductive coupling coefficient between different layers is as follows:

[0079]

[0080] Where N is the number of turns of the spiral wire, X is the distance between the layers of the printed circuit board, and A, B, C, and D are all fitting coefficients.

[0081] S3, selecting two printed circuit boards with spiral lines in opposite directions for connection, and connecting the spiral lines of two adjacent printed circuit boards end to end through through holes opened on the printed circuit boards.

[0082] S4. Based on the number of printed circuit board layers determined in step S2, the multi-layer printed circuit boards are sequentially connected according to the method of step S3 to obtain multi-layer inductor coils, thereby obtaining a target inductor sensor. Specific embodiments

[0084] This embodiment provides a printed circuit board spiral coil inductance sensor for use in a strong vibration environment, specifically an inductance sensor prepared by a multi-layer spiral coil printed circuit board, the spiral wire is a circular ring structure, and the multi-layer spiral wire ring is connected end to end, which can be used to produce a spiral tube coil. The spiral wire used to form the inductance coil is processed on the printed circuit board through the etching process of the printed circuit board.

[0085] In this embodiment, the printed circuit board can be made of ordinary printed circuit boards, high-frequency boards or high-temperature resistant boards, etc. In a specific embodiment, Rogers high-frequency boards can be selected, the spiral wire is generally copper wire, and the thickness of the printed circuit board can be set to 2mm, 2.5mm or 3mm, etc. according to production needs.

[0086] The spiral wire has directionality, including clockwise and counterclockwise directions. When routing between multi-layer printed circuit boards, the spiral wires of adjacent layers should be in opposite directions to ensure that the current directions of the spiral wires in each layer of printed circuit boards are consistent. When connected, the spiral wires of each layer are connected end to end through the through hole 4 in the printed circuit board. In specific applications, the spacing of the spiral wires can be adjusted as needed, generally around 0.1mm. The width of the spiral wire can be adjusted as needed, generally between 0.25mm-2.5mm. At the same time, the shape of the printed circuit board can be cut and marked according to the direction of the spiral wire for differentiation. The printed circuit board with spiral wires can be connected to multiple different printed circuit boards to form inductor coils for different purposes.

[0087] like Figure 1 and Figure 2 As shown, the inductor coil is composed of spiral lines processed by printed circuit board technology. The spiral lines on each layer of printed circuit board are consistent in direction relative to the central coordinate system, and the spiral lines of two adjacent layers of printed circuit boards are in opposite directions and are connected end to end through the vias of the printed circuit board. The spiral direction of the spiral line includes clockwise and counterclockwise directions. The printed circuit board is cut and marked or silk-screened according to the direction of the spiral line. Different inductor coils are formed by connecting different printed circuit boards to obtain an inductor sensor.

[0088] Specifically, Figure 1 and Figure 2As shown, the specific implementation method of this aspect adopts the following technical scheme: it includes a circular spiral wire 1, a first-layer printed circuit board 2 and an adjacent layer of printed circuit board 3, and the spiral wires of the adjacent layers of printed circuit boards are routed through the printed circuit board connecting through holes 4. The circular spiral wire 1 is printed on different printed circuit board layers such as a single-layer printed circuit board 2 and other layers of printed circuit boards through the printed circuit board etching process. The spiral directions of the circular spiral wires 1 on different printed circuit board layers on the first-layer printed circuit board 2 and the adjacent printed circuit board 3 should be opposite to ensure that the current directions in the spiral wires of each layer are consistent. The circular spiral wire 1 is connected between the single-layer printed circuit board 2 and the adjacent printed circuit board 3 through the printed circuit board connecting through hole 4. The printed circuit board shape with chamfer 5 is used to mark the direction of the spiral wire, which is convenient for the installation and deployment of multi-printed circuit board coil sensors.

[0089] The single-layer printed circuit board 2 and the adjacent-layer printed circuit board 3 are both part of a multi-layer printed circuit board. More layers can be stacked behind the adjacent-layer printed circuit board 3 as needed, and generally 10 layers, 12 layers, 14 layers, 16 layers or 18 layers can be selected, and generally no more than 64 layers.

[0090] When in use, a total inductance calculation model is constructed and the number of spiral layers is selected based on the target inductance value.

[0091] The total inductance calculation model is:

[0092] L 总 =nL+2L×(K 12 +K 13 +K 14 …+K 1n +K 23 +K 24 +…+K n(n-1) )

[0093] Wherein, L is the single-layer inductance value, K is the inductive coupling coefficient between different layers, and n is the number of printed circuit board layers.

[0094] The single-layer inductance value calculation formula is as follows:

[0095]

[0096] Where, μ0=4π10 -7 is the coefficient, N is the number of turns per layer.

[0097] The calculation formula of the inductive coupling coefficient between different layers is as follows:

[0098]

[0099] Wherein, N is the number of turns of the spiral wire, X is the distance between layers of the printed circuit board, and A, B, C, and D are all fitting coefficients. In one embodiment of the present invention, A=0.184, B=-0.525, C=1.038, and D=1.001.

[0100] In a specific embodiment, the thickness of the printed circuit board is between 2 mm, 2.5 mm or 3 mm. The line width of the circular spiral line 1 is between 0.25 mm and 2.5 mm. The line spacing of the circular spiral line 1 is generally about 0.1 mm.

[0101] In a specific embodiment, the direction of the circular spiral line 1 includes clockwise and counterclockwise directions, and in practical applications it can be clockwise or counterclockwise. The printed circuit board shape 5 with notched corners adopts a circular ring structure design, and the notched corners are marked around it, which can be used to mark the current direction of the circular spiral line 1.

[0102] The sensor provided by the present invention is suitable for use in the field of inductive sensors working in a strong vibration environment, such as pipelines for engines and machinery equipment, high-speed rotating probes, etc. When in use, the inductance and the DC impedance of the inductance can be adjusted by adjusting the line width, spacing and number of layers of the spiral wire. Compared with the traditional process, which requires mold opening and processing of the enameled wire skeleton, the method of the present invention is more flexible to use. At the same time, in specific application scenarios, the inductive sensor can be used alone for inductive ranging or multiple sensors can be connected for use in a magnetic field modulation environment.

[0103] The embodiments described above are only descriptions of the preferred implementation modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A printed circuit board spiral coil inductive sensor for use in a strong vibration environment, characterized in that: The inductor coil is composed of a spiral wire fixed on a printed circuit board, the spiral wire is a circular ring structure, and the number of layers of the printed circuit board is an even number greater than or equal to 2; The spiral direction of the spiral line includes a clockwise direction and a counterclockwise direction. The spiral lines of two adjacent layers of printed circuit boards are in opposite directions and are connected end to end through through holes opened on the printed circuit boards. The printed circuit boards are cut or silk-screened according to the direction of the spiral lines. Multiple inductance coils are formed by connecting multiple layers of printed circuit boards to obtain a target inductance sensor. The width and spacing of the spiral line are both greater than 0.08 mm; Build a total inductance calculation model and select the number of printed circuit board layers based on the target inductance value; The total inductance calculation model is: L 总 =nL+2L×(K 12 +K 13 +K 14 …+K 1n +K 23 +K 24 +…+K n(n-1) ) Where L is the single-layer inductance value, K is the inductive coupling coefficient between different layers, and n is the number of printed circuit board layers; The single-layer inductance value calculation formula is as follows: Where, μ0=4π10 -7 is the coefficient, N is the number of turns of a single-layer helix, d max is the maximum helix diameter, d min is the minimum helix diameter; The calculation formula of the inductive coupling coefficient between different layers is as follows: Where N is the number of turns of the spiral wire, X is the distance between the layers of the printed circuit board, and A, B, C, and D are all fitting coefficients.

2. The printed circuit board spiral coil inductance sensor for strong vibration environment according to claim 1, characterized in that: A=0.184, B=-0.525, C=1.038, D=1.

001.

3. The printed circuit board spiral coil inductance sensor for strong vibration environment according to claim 1, characterized in that: The number of layers of a printed circuit board ranges from 2 to 64.

4. The printed circuit board spiral coil inductance sensor for strong vibration environment according to claim 1, characterized in that: The printed circuit board thickness is 2mm, 2.5mm or 3mm.

5. The printed circuit board spiral coil inductance sensor for strong vibration environment according to claim 1, characterized in that: The helix pitch is 0.1±0.05mm.

6. The printed circuit board spiral coil inductance sensor for strong vibration environment according to claim 1, characterized in that: The width of the spiral line is between 0.25mm and 2.5mm.

7. The printed circuit board spiral coil inductance sensor for strong vibration environment according to claim 1, characterized in that: By adjusting the line width, spacing and number of layers of the spiral line, the inductance and the DC impedance of the inductor can be adjusted.

8. The printed circuit board spiral coil inductance sensor for use in a strong vibration environment according to claim 1, characterized in that: The spiral line is etched on the printed circuit board.

9. The printed circuit board spiral coil inductive sensor for use in a strong vibration environment according to claim 8, characterized in that: The inductive sensor can be used alone for inductive distance measurement or multiple sensors can be connected together for use in a magnetic field modulation environment.

10. A method for preparing the printed circuit board spiral coil inductance sensor for use in a strong vibration environment as claimed in claim 1, characterized in that: It includes the following steps: S1, etching a spiral line on a printed circuit board, and marking the printed circuit board according to the direction of the spiral line; S2. Determine the number of layers of the printed circuit board according to the target inductance value, specifically: Build a total inductance calculation model and select the number of printed circuit board layers based on the target inductance value; The total inductance calculation model is: L 总 =nL+2L×(K 12 +K 13 +K 14 …+K 1n +K 23 +K 24 +…+K n(n-1) ) Where L is the single-layer inductance value, K is the inductive coupling coefficient between different layers, and n is the number of printed circuit board layers; The single-layer inductance value calculation formula is as follows: Where, μ0=4π10 -7 is the coefficient, N is the number of turns of a single-layer helix, d max is the maximum helix diameter, d min is the minimum helix diameter; The calculation formula of the inductive coupling coefficient between different layers is as follows: Where N is the number of turns of the spiral wire, X is the distance between the layers of the printed circuit board, and A, B, C, and D are all fitting coefficients; S3, selecting two printed circuit boards with spiral lines in opposite directions for connection, and connecting the spiral lines of two adjacent printed circuit boards end to end through through holes opened on the printed circuit boards; S4. Based on the number of printed circuit board layers determined in step S2, the multi-layer printed circuit boards are sequentially connected according to the method of step S3 to obtain multi-layer inductor coils, thereby obtaining a target inductor sensor.

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