Hall carbon film linear displacement sensor and processing method

Abstract

The invention relates to a Hall carbon film linear displacement sensor and a processing method, and relates to the technical field of detection, and the Hall carbon film linear displacement sensor comprises a carbon film, a Hall element, a magnetic ring and a divider resistor. The plurality of Hall elements are electrically connected with the carbon film, and are uniformly distributed along the length direction of the carbon film; the magnetic ring is connected to a to-be-measured medium, the magnetic ring and the carbon film are arranged at an interval, and the magnetic ring has a stroke sliding along the length direction of the carbon film; the divider resistor is electrically connected to the starting point of the carbon film; when the magnetic ring is overlapped with any one Hall element, the corresponding Hall element outputs voltage, and the starting point of the carbon film outputs a corresponding voltage value according to the output voltage and is used for metering the moving distance of the magnetic ring. The method has the effect of improving the detection precision of the sensor.

Description

Technical Field

[0001] The present application relates to the field of detection technology, and in particular to a Hall carbon film linear displacement sensor and a processing method thereof. Background Art

[0002] A linear displacement sensor is a sensor used to measure the displacement of an object in a straight line. It is mainly divided into two types: contact and non-contact. Among them, the non-contact linear displacement sensor has a high sealing performance and can be measured in a liquid environment (for example: measuring the displacement of the output shaft of a hydraulic cylinder).

[0003] The non-contact displacement sensor mainly includes a shell, a circuit structure placed inside the shell, and a magnetic ring placed outside the shell. Among them, the circuit structure mainly includes a number of resistors connected in series, a voltage divider resistor, and a number of reed switches. The resistance values ​​of the resistors connected in series need to be consistent. A number of reed switches are used as induction switches and are connected to a plurality of resistors one by one. The plurality of reed switches are evenly distributed along the length direction of the shell. When the magnetic ring overlaps with the Nth reed switch, the reed switch is activated, and the voltage divider voltage is converted to obtain the displacement value, thereby achieving the purpose of measurement.

[0004] The reed switch mainly consists of two internal contact pieces, which are in contact under the action of a magnetic field. However, in some harsh working environments (such as mining operations), there is high vibration, which causes the reed switch to be activated without being affected by a magnetic ring, resulting in poor stability of the displacement sensor. At the same time, there will be deviations in the resistance values ​​between resistors, and temperature drift will occur, and the measurement accuracy of the sensor needs to be improved. Summary of the invention

[0005] The purpose of this application is to provide a Hall carbon film linear displacement sensor with higher detection accuracy.

[0006] In the first aspect, the present application provides a Hall carbon film linear displacement sensor adopting the following technical solution:

[0007] A Hall carbon film linear displacement sensor, comprising:

[0008] A carbon film having a starting point and an end point;

[0009] A plurality of Hall elements are provided, and the plurality of Hall elements are electrically connected to the carbon film and are evenly distributed along the length direction of the carbon film;

[0010] A magnetic ring connected to the medium to be tested, the magnetic ring is spaced apart from the carbon film and has a sliding stroke along the length direction of the carbon film;

[0011] A voltage dividing resistor electrically connected to a starting point of the carbon film;

[0012] When the magnetic ring overlaps with any one of the Hall elements, the Hall element outputs a voltage corresponding to the voltage output, and the starting point of the carbon film outputs a corresponding voltage value according to the output voltage, which is used to measure the moving distance of the magnetic ring.

[0013] Furthermore, the carbon film is laser etched to form a plurality of carbon film resistors evenly distributed along the length direction of the carbon film, the resistance values ​​of the plurality of carbon film resistors are consistent, and the plurality of Hall elements are connected one-to-one.

[0014] Furthermore, the carbon film resistor is connected to the corresponding carbon film resistor through a circuit board, and a plurality of limit grooves are formed on the carbon film after laser etching. A plurality of limit rings are arranged on a side of the circuit board away from the carbon film resistor, and the plurality of limit rings are arranged in one-to-one correspondence with the plurality of limit grooves, and the limit rings are at least partially placed in the corresponding limit grooves.

[0015] Furthermore, an elastic sheet is arranged in the limiting groove.

[0016] Furthermore, the carbon film resistor comprises:

[0017] Main body;

[0018] The trimming part is integrally formed with the main body, and the trimming part extends out of the circuit board.

[0019] Furthermore, it also includes a plurality of serial drivers, and the plurality of Hall elements are divided into a plurality of groups, and the plurality of groups of Hall elements are connected to the plurality of serial drivers in a one-to-one correspondence.

[0020] Furthermore, the resistance of the voltage-dividing resistor is at least an integer multiple of the total resistance of the plurality of carbon film resistors.

[0021] Furthermore, it also includes a signal processing structure arranged at the starting point, the signal processing structure including:

[0022] MCU, an input terminal of the MCU is electrically connected to a starting point of the carbon film;

[0023] The analysis unit is electrically connected to the output terminal of the MCU.

[0024] In a second aspect, the present application provides a method for processing a Hall carbon film linear displacement sensor, comprising the following steps:

[0025] S1. Setting a program on the laser resistor trimmer so that the laser resistor trimmer performs preliminary processing on the carbon film to form a plurality of carbon film resistors;

[0026] S2, detecting the actual resistance value of the carbon film resistor, and presetting a calibrated resistance value, and based on the deviation value between the actual resistance value and the calibrated resistance value, performing fine processing on the carbon film resistor on the trimming part;

[0027] S3, positioning and installing the Hall element on the circuit board, inserting the limit ring on the circuit board into the corresponding limit groove, and then fastening the circuit board to the carbon film;

[0028] S4, detecting whether the spacing between adjacent Hall elements is consistent;

[0029] S5. Connect the voltage divider resistor to complete the final installation.

[0030] In summary, the present application includes at least one of the following beneficial technical effects:

[0031] 1. In the present application, a Hall element is provided as a trigger switch. Compared with the method of using a reed switch as a trigger switch, the combination of the Hall element and the magnetic ring not only retains the non-contact working form between the magnetic ring and the circuit, but also the Hall element has high shock resistance, which ensures the stability of the sensor, reduces the possibility of incorrect displacement information output by the sensor due to vibration, and improves the accuracy of the sensor.

[0032] 2. A carbon film is provided in the present application, and a plurality of carbon film resistors are formed after etching. Compared with the method of operating multiple resistors in series, the carbon film is formed by high-temperature hot pressing and has higher heat resistance. This reduces the possibility of temperature drift when the sensor is working, and also reduces the resistance deviation between adjacent resistors, and the accuracy of the sensor is further improved.

[0033] 3. The carbon film resistor in the present application includes a main body and a trimming part, and the trimming part is arranged to extend out of the circuit board. In this way, when trimming the carbon film resistor, there is no need to remove the circuit board from the carbon film, thereby reducing the deviation caused by disassembly when the sensor is used again, and optimizing the steps for repairing the carbon film resistor.

[0034] 4. In the present application, a circuit board is provided, and a limit ring is installed on one side of the circuit board. With the help of a limit groove formed on the carbon film when processing the carbon film resistor by a laser adjuster, the circuit board can be better fixed to the carbon film by the limit ring, thereby improving the assembly accuracy between the circuit board and the carbon film. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 is a circuit diagram of the Hall carbon film linear displacement sensor in this application;

[0036] Figure 2 It is a working schematic diagram of the Hall carbon film linear displacement sensor in this application;

[0037] Figure 3 is a top view of the Hall carbon film linear displacement sensor in the present application;

[0038] Figure 4 It is a cross-sectional view of the Hall carbon film linear displacement sensor in this application.

[0039] In the figure, 1. carbon film; 11. carbon film resistor; 111. main body; 112. trimming part; 12. limit groove; 13. connection point; 2. Hall element; 3. magnetic ring; 4. voltage divider resistor; 5. circuit board; 6. limit ring; 7. elastic sheet; 8. serial driver; 9. signal processing structure; 91. MCU; 92. analysis unit; 10. signal regulator. DETAILED DESCRIPTION

[0040] The following will be combined with the attached Figure 1-4 The technical solution of the present application is described clearly and completely. The following embodiments are exemplary and are only used to explain the present application, and cannot be interpreted as limiting the present application. In the following description, the same symbols are used to represent the same or equivalent elements, and repeated descriptions are omitted.

[0041] In the description of the present application, it should be understood that the terms "upper", "lower", "inside", "outside", "left", "right", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, or are the orientations or positional relationships in which the products of the present application are conventionally placed when in use, or are the orientations or positional relationships conventionally understood by those skilled in the art. They are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0042] In addition, the terms "installed", "connected" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0043] It should be further understood that the term “and / or” used in the specification and corresponding claims of this application refers to any and all possible combinations of one or more of the listed items.

[0044] A Hall carbon film linear displacement sensor, referring to Figure 1 and Figure 2, including a carbon film 1, a Hall element 2, a magnetic ring 3 and a voltage-dividing resistor 4; a plurality of Hall elements 2 are provided, and the plurality of Hall elements 2 are electrically connected to the carbon film 1 and are evenly distributed along the length direction of the carbon film 1; the magnetic ring 3 is connected to the medium to be measured, the magnetic ring 3 is spaced apart from the carbon film 1, and has a sliding stroke along the length direction of the carbon film 1; the carbon film 1 has a starting point and an end point, and the voltage-dividing resistor 4 is electrically connected to the starting point of the carbon film 1.

[0045] Specifically, a plurality of connection points 13A1 (i.e., the starting point), A2, A3, ..., An, An+1 (i.e., the end point) are uniformly distributed on the carbon film 1. The plurality of connection points 13 correspond to the plurality of Hall elements 2 one by one. When the connection points 13 located at different positions of the magnetic ring 3 overlap with the corresponding Hall element 2, a magnetic field is applied to the corresponding Hall element 2. Under the action of the magnetic field, the corresponding Hall element 2 is activated, and the corresponding Hall element 2 outputs a voltage (fixed VDD voltage). The connection points 13 on the carbon film 1 and the voltage divider resistor 4 form an effective loop.

[0046] A portion of the carbon film 1 is connected to the power circuit. As the distance the magnetic ring 3 moves becomes longer, more portions of the carbon film 1 are connected to the power circuit, and the partial pressure of the carbon film 1 becomes higher. The starting point of the carbon film 1 outputs a corresponding voltage value based on the output voltage. By detecting the voltage outputted at the starting point of the carbon film 1, the moving distance of the magnetic ring 3 is calculated.

[0047] In a specific embodiment, the resistance value of the voltage-dividing resistor 4 is set to 10kΩ, the portion of the carbon film 1 corresponding to the adjacent connection points 13 is set to 1kΩ, and the output voltage is set to 5V. Taking the movement of the magnetic ring 3 to the connection point 13A5 as an example, the output voltage of the starting point of the resistor plate is calculated to be 5 / (5+10)*5≈3.3334V.

[0048] Further, refer to Figure 1 , and also includes a signal processing structure 9 set at the starting point, the signal processing structure 9 includes an MCU91 and an analysis unit 92, the input end of the MCU91 is electrically connected to the starting point of the carbon film 1; the analysis unit 92 is electrically connected to the output end of the MCU91.

[0049] Among them, MCU91 collects the output voltage of the starting point and then sends it to the analysis unit 92. The analysis unit 92 analyzes the voltage signal, obtains the position of the magnetic ring 3 (ie, the corresponding connection point 13) according to the output voltage, and outputs the position information to the next unit.

[0050] Compared with the method of using a reed switch as a trigger switch, the combination of the Hall element 2 and the magnetic ring 3 not only retains the non-contact working form between the magnetic ring 3 and the circuit, but also the Hall element 2 has a high shock resistance, which ensures the stability of the sensor, reduces the possibility of incorrect displacement information output by the sensor due to vibration, and improves the accuracy of the sensor.

[0051] At the same time, compared with the method of operating multiple resistors in series, the carbon film 1 is formed by high-temperature hot pressing and has higher heat resistance, which reduces the possibility of temperature drift when the sensor is working, and the accuracy of the sensor is further improved.

[0052] It should be noted that a signal conditioner 10 is further provided between the carbon film resistor 11 and the MCU 91 . The signal conditioner 10 changes the impedance characteristic of the voltage signal and then outputs it to the MCU 91 , so as to protect the analysis unit 92 .

[0053] Furthermore, the resistance of the voltage-dividing resistor 4 is at least an integer multiple of the total resistance of the plurality of carbon film resistors 11. In a specific embodiment, the resistance of the voltage-dividing resistor 4 may be 10 times the total resistance of the plurality of carbon film resistors 11, so that when the magnetic ring 3 slides, the curve formed by the voltage division of the carbon film resistors 11 is more linear, further improving the measurement accuracy of the sensor.

[0054] Further, refer to Figure 1 The sensor further includes a plurality of serial drivers 8 , wherein the plurality of Hall elements 2 are divided into a plurality of groups, and the plurality of groups of Hall elements 2 are connected to the plurality of serial drivers 8 in a one-to-one correspondence.

[0055] In a specific embodiment, ten Hall elements 2 are provided, and the ten Hall elements 2 are equally divided into two groups. Correspondingly, two serial drivers 8 are provided, and the input ends of the two serial drivers 8 are both connected to the MCU 91 , and the output ends of the two serial drivers 8 are both connected to the corresponding Hall elements 2 .

[0056] MCU91 will send a pulse signal to the Hall element 2, and the pulse signal will further drive the Hall unit through the serial driver 8, that is, the two actions of MCU91 acquiring and sending signals are synchronous. During operation, the serial driver 8 can filter, amplify and process the signal to improve the quality and accuracy of the signal and ensure the accuracy and reliability of the displacement measurement results.

[0057] Furthermore, the carbon film 1 is laser etched to form a plurality of carbon film resistors 11 evenly distributed along the length direction of the carbon film 1 . The resistance values ​​of the plurality of carbon film resistors 11 are consistent and they are connected to the plurality of Hall elements 2 in a one-to-one correspondence.

[0058] Compared with the method of connecting multiple resistors in series, the carbon film resistor 11 is processed on the carbon film 1, so that the carbon film resistors 11 have higher integrity. After being trimmed by the laser trimmer, the resistance of the carbon film resistor 11 is highly consistent compared with the method of connecting multiple resistors in series (the resistance value of conventional resistors has a certain deviation), which further improves the accuracy of the sensor.

[0059] Furthermore, the carbon film resistor 11 is connected to the corresponding carbon film resistor 11 through the circuit board 5. A plurality of limit grooves 12 are formed on the carbon film 1 after laser etching. A plurality of limit rings 6 are arranged on the side of the circuit board 5 facing away from the carbon film resistor 11. The plurality of limit rings 6 are arranged one by one corresponding to the plurality of limit grooves 12, and the limit rings 6 are at least partially placed in the corresponding limit grooves 12.

[0060] The circuit board 5 has connection points (pads). When assembling the sensor, the Hall element 2 is first connected to the circuit board 5, and then the circuit board 5 is further installed on the carbon film 1. With the help of the limit groove 12 formed on the carbon film 1 by the laser adjuster when processing the carbon film resistor 11, the circuit board 5 can be better fixed to the carbon film 1 by the limit ring 6, thereby improving the assembly accuracy between the circuit board 5 and the carbon film 1.

[0061] Furthermore, an elastic piece 7 is arranged in the limiting groove 12. The material of the elastic piece 7 can be specifically set according to actual conditions. In a specific embodiment, the elastic piece is made of silicone material.

[0062] When the sensor is in a vibrating environment, the elastic sheet 7 can serve as a buffer between the circuit board 5 and the carbon film 1 to reduce friction and collision between the circuit board 5 and the carbon film 1, thereby ensuring stable operation and accuracy of the sensor.

[0063] Further, refer to Figure 3 and Figure 4 The carbon film resistor 11 includes a main body 111 and a trimming part 112. The trimming part 112 is integrally formed with the main body 111. When the laser resistor trimmer processes the carbon film resistor 11 on the carbon film 1, the limiting groove 12 will be etched first. At this time, the carbon film resistor 11 is initially formed, wherein the volume of the main body 111 is larger than that of the trimming part 112. When further finishing is performed, in order to ensure that the sizes of the limiting grooves 12 are consistent, only the trimming part 112 is further etched. This ensures the assembly accuracy between the circuit board 5 and the carbon film 1.

[0064] Correspondingly, refer to Figure 4 The trimming portion 112 extends out of the circuit board 5 .

[0065] The laser resistor trimmer mainly achieves the purpose of resistance adjustment by further engraving on the trimming portion 112. The carbon film resistor 11 will age with the increase of service life, which will cause the resistance value of the carbon film resistor 11 to increase. In order to ensure the measurement accuracy, the carbon film resistor 11 needs to be refined again.

[0066] The trimming portion 112 is arranged to extend out of the circuit board 5, so that when trimming the carbon film resistor 11, there is no need to remove the circuit board 5 from the carbon film 1, thereby reducing the deviation caused by disassembly when the sensor is used again and optimizing the steps of reworking the carbon film resistor 11.

[0067] In addition, the present application also provides a method for processing a Hall carbon film linear displacement sensor, comprising the following steps:

[0068] S1, setting a program on the laser resistor trimmer so that the laser resistor trimmer performs preliminary processing on the carbon film 1 to form a plurality of carbon film resistors 11;

[0069] S2, detecting the actual resistance value of the carbon film resistor 11, and presetting a calibrated resistance value, and based on the deviation value between the actual resistance value and the calibrated resistance value, performing fine processing on the carbon film resistor 11 on the trimming portion 112;

[0070] S3, positioning and installing the Hall element 2 on the circuit board 5, inserting the limiting ring 6 on the circuit board 5 into the corresponding limiting groove 12, and then fastening the circuit board 5 to the carbon film 1;

[0071] S4, detecting whether the spacing between adjacent Hall elements 2 is consistent;

[0072] S5. Connect the voltage divider resistor 4 to complete the final installation.

[0073] The embodiments of this specific implementation are all preferred embodiments of the present application, and are not intended to limit the protection scope of the present application. The same components are represented by the same figure marks. Therefore, any equivalent changes made based on the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. A Hall carbon film linear displacement sensor, characterized in that: include: A carbon film (1) having a starting point and an end point; A plurality of Hall elements (2) are provided, and the plurality of Hall elements (2) are all electrically connected to the carbon film (1) and are evenly distributed along the length direction of the carbon film (1); A magnetic ring (3) connected to the medium to be measured, the magnetic ring (3) being spaced apart from the carbon film (1) and having a sliding stroke along the length direction of the carbon film (1); A voltage dividing resistor (4) electrically connected to a starting point of the carbon film (1); When the magnetic ring (3) overlaps with any one of the Hall elements (2), the corresponding Hall element (2) outputs a voltage, and the starting point of the carbon film (1) outputs a corresponding voltage value based on the output voltage, which is used to measure the moving distance of the magnetic ring (3).

2. A Hall carbon film linear displacement sensor according to claim 1, characterized in that: The carbon film (1) is laser etched to form a plurality of carbon film resistors (11) evenly distributed along the length direction of the carbon film (1); the resistance values ​​of the plurality of carbon film resistors (11) are consistent and they are connected to the plurality of Hall elements (2) in a one-to-one correspondence.

3. A Hall carbon film linear displacement sensor according to claim 2, characterized in that: The carbon film resistor (11) is connected to the corresponding carbon film resistor (11) via a circuit board (5), and the carbon film (1) is formed with a plurality of limiting grooves (12) after laser etching; A plurality of limiting rings (6) are arranged on a side of the circuit board (5) facing away from the carbon film resistor (11); the plurality of limiting rings (6) are arranged in one-to-one correspondence with the plurality of limiting grooves (12); and the limiting rings (6) are at least partially disposed in the corresponding limiting grooves (12).

4. A Hall carbon film linear displacement sensor according to claim 3, characterized in that: An elastic sheet (7) is arranged in the limiting groove (12).

5. The Hall carbon film linear displacement sensor according to claim 3, characterized in that: The carbon film resistor (11) comprises: A main body (111); The trimming portion (112) is integrally formed with the main body portion (111), and the trimming portion (112) extends out of the circuit board (5).

6. The Hall carbon film linear displacement sensor according to claim 1, characterized in that: It also includes a plurality of serial drivers (8), and the plurality of Hall elements (2) are divided into a plurality of groups, and the plurality of groups of Hall elements (2) are connected to the plurality of serial drivers (8) in a one-to-one correspondence.

7. The Hall carbon film linear displacement sensor according to claim 1, characterized in that: The resistance value of the voltage-dividing resistor (4) is at least an integer multiple of the total resistance value of the plurality of carbon film resistors (11).

8. The Hall carbon film linear displacement sensor according to claim 1, characterized in that: The device also includes a signal processing structure (9) arranged at the starting point, wherein the signal processing structure (9) includes: An MCU (91), wherein an input terminal of the MCU (91) is electrically connected to a starting point of the carbon film (1); The analysis unit (92) is electrically connected to the output end of the MCU (91).

9. A method for processing a Hall carbon film linear displacement sensor, used for processing the Hall carbon film (1) linear displacement sensor according to claim 5, characterized in that: The following steps are involved: S1, setting a program on a laser resistor trimmer so that the laser resistor trimmer performs preliminary processing on the carbon film (1) to form a plurality of carbon film resistors (11); S2, detecting the actual resistance value of the carbon film resistor (11), presetting a calibrated resistance value, and performing fine processing on the carbon film resistor (11) on the trimming portion (112) based on the deviation value between the actual resistance value and the calibrated resistance value; S3, positioning and installing the Hall element (2) on the circuit board (5), inserting the limiting ring (6) on the circuit board (5) into the corresponding limiting groove (12), and then fastening the circuit board (5) to the carbon film (1); S4, detecting whether the spacing between adjacent Hall elements (2) is consistent; S5. Connect the voltage divider resistor (4) to complete the final installation.

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