Production and assembly method of high-precision pull rope sensor

Abstract

The invention relates to a production and assembly method of a high-precision pull rope sensor, which comprises the following steps of: 1) improving the structure of the pull rope sensor so as to meet the requirements of low cost and high precision; 2) external calibration of the whole detection assembly; 3) assembling the structure of the pull rope sensor; and 4) calibrating the length. Compared with the prior art, the invention has the advantages of low cost, high precision, stable structure, reliable installation, strong manufacturability and the like.

Description

Technical Field

[0001] This invention relates to the field of pull-wire sensors, and in particular to a method for manufacturing and assembling a high-precision pull-wire sensor. Background Technology

[0002] A pull-rope displacement sensor (pull-rope sensor) is a sensor used to detect the length of a pulled-out wire rope and convert it into an electrical signal, thereby achieving accurate measurement of linear displacement. Its mechanical parts include a housing, a coil spring, a winding reel, a rotating shaft, and a PCB board with a processor and sampling circuitry inside the housing. When the wire rope of the pull-rope sensor is pulled outward, it drives the internal winding reel to rotate. The Hall effect chip on the PCB board collects the number of rotations and the angle of the winding reel, and then converts it into a length output.

[0003] Currently, the main technical solution for achieving high-precision measurement in draw-wire displacement sensors is the use of high-precision Hall effect chips. High-precision Hall effect chips, due to their high accuracy and stability, do not require calibration before assembly. However, as the core component of high-precision draw-wire sensors, the cost of high-precision Hall effect chips is several times that of ordinary Hall effect chips. Furthermore, most high-precision Hall effect chips are supplied by foreign companies, resulting in insufficient production capacity and low domestic substitution potential. Therefore, to reduce costs, it is necessary to make reasonable improvements to the product structure and production assembly methods based on the use of low-cost, low-precision Hall effect chips, in order to improve the measurement accuracy of draw-wire sensor products and meet customer requirements. Summary of the Invention

[0004] To address the technical problems in the background art, the present invention provides a method for manufacturing and assembling a high-precision draw rope sensor, comprising the following steps:

[0005] 1) The structure of the pull-rope sensor has been improved to meet the requirements of low cost and high precision;

[0006] 2) External calibration of the entire testing component;

[0007] 3) Structural assembly of the pull-rope sensor;

[0008] 4) Length calibration.

[0009] Furthermore, in step 1), the structural improvement of the rope sensor specifically includes the overall structural design of the measurement component, the improvement of the shaft system structure, and the adjustment of other structures.

[0010] Furthermore, the overall structural design of the measurement component specifically involves constructing a PCB board with a Hall chip, a mounting bracket, a drive gear with a first magnet installed, and a driven gear with a second magnet installed as a whole detection component.

[0011] Furthermore, in the overall measuring component, a circular mounting hole is provided in the middle of the fixed frame to avoid the installation of the transmission gear. On the left and right sides of the circular mounting hole, a driving gear and a driven gear are rotatably mounted via a rotating shaft. A first magnet and a magnetic shielding ring are fixedly mounted on the driving gear, and a second magnet and a magnetic shielding ring are fixedly mounted on the driven gear. The driving gear and the driven gear mesh with the transmission gear on the left and right sides respectively, and all three have the same module. The number of teeth and radius of the driving gear are smaller than those of the driven gear. The PCB board is fixed on the fixed frame. On the lower surface of the PCB board, one first Hall chip and one second Hall chip are respectively provided at the positions directly opposite the first magnet and the second magnet. In addition, a mounting hole is provided on the PCB board at the position corresponding to the installation of the transmission gear to avoid the drive gear.

[0012] Furthermore, to achieve redundant measurement, two first Hall chips and two second Hall chips are respectively installed on the upper and lower surfaces of the PCB board at positions directly opposite the first and second magnets.

[0013] Furthermore, the improvement to the shaft system structure specifically includes:

[0014] An annular groove for mounting and fixing retaining rings is provided in the transmission part of the transmission shaft near the lower shoulder.

[0015] A circular pin hole is opened radially in the transmission part of the transmission shaft. After the transmission pin passes through the pin hole on the transmission shaft, it is installed from top to bottom in the U-shaped transmission pin mounting groove with the opening facing upward. The transmission pin mounting groove and the transmission pin are interference fit.

[0016] A first bearing and a sealing ring are provided at the contact position between the lower section of the transmission part and the transverse partition of the coil spring fixing seat in the transmission shaft;

[0017] A third bearing and shaft seal are provided at the contact position between the upper section of the transmission part and the center opening of the PCB board mounting base in the transmission shaft.

[0018] An annular protrusion is integrally formed on the lower surface of the drive section of the winding reel. The contact position between the transverse partition of the coil spring fixing seat and the drive section in the drive shaft is set in a Z-shaped structure. A second bearing is provided in the space formed by the annular protrusion and the Z-shaped structure.

[0019] Furthermore, the adjustments to the other structures are as follows:

[0020] A first threaded hole is uniformly provided circumferentially on the outer edge of the bottom plate of the housing of the pull rope sensor. A second threaded hole is uniformly provided circumferentially on the outer side of the outer edge plate of the coil spring fixing seat. Both the upper and lower ends of the second threaded hole are provided with internal threads. The first threaded hole of the housing bottom plate is fixedly connected to the coil spring fixing seat 16 by screws cooperating with the lower end of the second threaded hole.

[0021] The outer side of the outer edge of the PCB board mounting base is uniformly provided with a third threaded hole for fixed connection with the upper port of the second threaded hole of the coil spring mounting base 16. The outer edge of the bottom of the housing cover is uniformly provided with a fourth threaded hole for fixed connection with the upper port of the second threaded hole of the coil spring mounting base. The third threaded hole and the fourth threaded hole are staggered and correspond to the upper port of the second threaded hole respectively.

[0022] Multiple vent holes are opened circumferentially on the outer side of the casing.

[0023] Furthermore, step 2) specifically includes the following steps:

[0024] 21) Fix the entire detection component to be calibrated on the base of the calibration fixture and adjust its horizontal position;

[0025] 22) Adjust the height of the motor, thereby driving the rotating gear to move from top to bottom so that the rotating gear meshes with both the driving gear and the driven gear at the same time;

[0026] 23) The motor drives the rotating gear component to rotate at a set speed by controlling the calibration PC. During the rotation process within a set time, the average value of multiple preset angle calibration points is taken sequentially, and the angle between two adjacent length calibration points is calibrated by using linear interpolation.

[0027] Furthermore, step 3) specifically includes the following steps:

[0028] 31) Assemble the winding reel: Assemble the drive pin and sealing ring onto the drive shaft, pass them from top to bottom through the center hole of the winding reel, and then use an interference fit to install the drive pin in the drive pin mounting groove to form the winding reel accessory;

[0029] 32) Installing the coil spring: First, install the second bearing on the coil spring mounting base; then, install the winding reel accessory from top to bottom on the coil spring mounting base, so that the second bearing is installed in the space formed by the annular protrusion and the Z-shaped structure; next, flip the coil spring mounting base with the winding reel accessory, and after installing the first bearing and the retaining ring on the drive shaft, install the rotating sleeve, install the coil spring and fill it with lubricating oil; finally, fix the housing base plate to the coil spring mounting base with screws;

[0030] 33) Winding the wire rope: First, pre-tighten the spring in the forward direction to the first set number of turns N, then tie one end of the wire rope to the winding wheel, and loosen the spring in the reverse direction to the second set number of turns M (N>M). During this process, the wire rope is wound on the winding wheel, and a pull ring is set at the other end of the wire rope.

[0031] 34) Install PCB board mounting bracket: After installing the shaft seal on the bottom surface of the PCB board mounting bracket, put it on the drive shaft, and then install the third bearing. After ensuring that the drive shaft is vertically installed in the center position inside the housing, fix the PCB board mounting bracket to the coil spring mounting bracket with screws.

[0032] 35) Install the calibrated detection assembly: Fix the mounting bracket in the detection assembly to the PCB board mounting base, then install the transmission gear on the top of the transmission shaft and make the transmission gear fully mesh with the driving gear and the driven gear respectively. Install the connector on the housing cover and connect it to the PCB board through the cable. Finally, fix the housing cover to the coil spring mounting base to complete the structural assembly process of the current pull rope sensor product.

[0033] Furthermore, step 4) specifically includes the following steps:

[0034] The pull rope sensor product to be calibrated and the motor are fixed on the calibration fixture. The pull ring is sleeved on the output shaft of the motor. The rotation of the motor drives the pull ring of the pull rope sensor to pull out the wire rope. A calibration magnetic encoder is set between the motor and the pull rope sensor product to be calibrated to detect the length of the wire rope being pulled out. When the motor rotates and the wire rope is pulled out, if the magnetic encoder detects that the length of the wire rope pulled out is the set length calibration point ln, the angles of the driving gear and driven gear corresponding to the length calibration point ln are recorded as the calibrated angles. Finally, the calibration data between two adjacent length calibration points is determined by multi-segment linear interpolation, and the calibration is completed.

[0035] Compared with the prior art, the present invention has the following advantages:

[0036] I. Low cost and high precision: Taking into account the low precision characteristics of low-cost Hall chips, this invention designs the PCB board with low precision Hall chip, driving gear, driven gear and fixing frame as a calibrated high precision whole prefabricated component. While reducing costs, it greatly improves detection accuracy. Repeatability and zero point deviation are both within 0.2%, and nonlinearity is within 0.4%, reaching the international advanced level.

[0037] II. Stable structure and reliable installation: This invention takes into account the overall accuracy and installation requirements of the detection components, and makes structural improvements to the shaft system and housing, which not only further enhances stability but also takes into account the subsequent installation process, thereby improving the ease of installation and manufacturing consistency.

[0038] Third, strong manufacturability: The present invention uses a measurement component based on the multi-turn measurement principle to replace the worm gear structure, which avoids the impact of the assembly clearance of the worm gear and worm on the measurement accuracy and consistency during assembly, greatly improving manufacturability and production efficiency. Attached Figure Description

[0039] Figure 1 This is a flowchart of the method of the present invention;

[0040] Figure 2 This is a cross-sectional view of the pull-wire sensor structure;

[0041] Figure 3 This is a schematic diagram of the overall structure of the detection component;

[0042] Figure 4 A cross-sectional view of the overall structure of the inspection component;

[0043] Figure 5 This is a schematic diagram of the fixed frame structure;

[0044] Figure 6 This is a schematic diagram of the drive shaft structure;

[0045] Figure 7 This is a schematic diagram of the entire testing component during calibration.

[0046] Explanation of reference numerals in the attached figures:

[0047] 1. Winding reel, 2. Drive gear, 3. First magnet, 4. First Hall chip, 5. Drive shaft, 6. Drive gear, 7. Driven gear, 8. Magnetic ring, 9. Second magnet, 10. Second Hall chip, 11. PCB board, 12. Fixing bracket, 13. Coil spring, 14. Drive pin, 15. Fixing screw, 16. Coil spring fixing seat, 17. PCB board fixing seat, 18. Housing bottom plate, 19. Connector, 20. Housing top cover, 21. Rotating sleeve, 22. Outlet end, 23. First bearing, 24. Second bearing, 25. Third bearing, 26. Shaft seal. Detailed Implementation

[0048] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0049] It should be noted that in this specification, similar reference numerals and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0050] In the description of this embodiment, it should be noted that the terms "upper", "lower", "inner", "bottom", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship that the product of the invention is usually placed in during use. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the present invention.

[0051] The terms “first”, “second”, etc., are used only to distinguish descriptions and should not be interpreted as indicating or implying relative importance.

[0052] In the description of this embodiment, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set up," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this embodiment based on the specific circumstances.

[0053] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0054] Example

[0055] like Figure 1 As shown, the product structure of a high-precision pull-cord sensor based on a low-cost Hall chip is presented. Taking into full account the low-precision characteristics of the low-cost Hall chip and the high-precision requirements of the product, this invention designs a calibration and installation method for the high-precision pull-cord sensor. The specific steps are as follows:

[0056] 1) Structural improvement design: The structure of the pull rope sensor is improved to meet the requirements of low cost, high precision and easy installation, and spare parts are made for each component of the improved pull rope sensor;

[0057] like Figure 2 As shown, the improved design of the drawstring sensor in this invention mainly includes the overall structural design of the measuring component, the improvement of the shaft system, and adjustments to other structures. The improvements to each structure are described below:

[0058] 1.1 Overall Structural Design of the Measurement Component

[0059] like Figure 3As shown, considering the low precision of low-cost Hall chips, in order to improve the measurement accuracy of the rope-pulling sensor product, this invention creatively constructs a detection assembly consisting of a PCB board 11 with a low-cost Hall chip, a fixing frame 12, a driving gear 2 with a first magnet 3 installed, and a driven gear 7 with a second magnet 9 installed. Figure 3 In the middle, the gear is the transmission gear 6). Compared with the high-precision Hall chip which does not require external calibration, this detection component requires an external calibration process before installation. After the external calibration is completed, it is necessary to ensure that the relative positions of each component (especially the relative positions between the Hall chip and the corresponding magnet) do not change. The entire component needs to be installed in the subsequent installation process to ensure high calibration accuracy. At the same time, the specific structure also needs to be adjusted when considering the convenience and reliability of the overall installation.

[0060] like Figure 4 As shown, in the overall detection assembly, a circular mounting hole is opened in the middle of the fixing frame 12 to avoid mounting the transmission gear 6. A driving gear 2 and a driven gear 7 are rotatably mounted on corresponding positions on the left and right sides of the circular mounting hole via rotating shafts. A first magnet 3 and a magnetic shielding ring 8 to prevent magnetic interference are fixedly mounted on the upper surface of the driving gear 2. A second magnet 9 and a magnetic shielding ring 8 to prevent magnetic interference are fixedly mounted on the upper surface of the driven gear 7. The driving gear 2 and the driven gear 7 mesh with the transmission gear 6 on the left and right sides respectively, and all three have the same module. The number of teeth and radius of the driving gear 2 are smaller than those of the driven gear 7. Furthermore, the PCB board 11 is secured by screws. The mounting holes of the fixed bracket 12 are fixed on the PCB board 11. One first Hall chip 4 and one second Hall chip 10 are respectively provided on the lower surface of the PCB board 11 at the position directly opposite the first magnet 3 and the second magnet 9. In addition, in order to achieve redundant measurement, two first Hall chips 4 and two second Hall chips 10 can be respectively provided on the upper and lower surfaces of the PCB board 11 at the position directly opposite the first magnet 3 and the second magnet 9. At the same time, the corresponding filtering acquisition circuit and processor chip can be set on the PCB board 11. In addition, in order to facilitate the overall installation, mounting holes are also opened on the PCB board 11 at the position corresponding to the installation of the transmission gear 6 to avoid interference.

[0061] like Figure 5 As shown, the mounting bracket 12 is U-shaped and includes a base plate and side plates on both sides. A circular mounting hole is opened in the center of the base plate, and the mounting holes for the drive gear 2 and the driven gear 7 are located on the left and right sides of the circular mounting hole. A rotating shaft and a bearing are provided in the mounting hole. Screw holes for fixing to the PCB board mounting base 17 with screws, screw holes for fixing to the PCB board 11, and positioning protrusions for positioning the PCB board 11 are respectively opened on the side plates. In this way, during production assembly, the mounting bracket 12 can securely install the PCB board 11 with screws and positioning protrusions.

[0062] In addition, to ensure that the transmission gear 6 can be smoothly installed in place and fully mesh with the driving gear 2 and driven gear 7 without squeezing or bumping during product assembly, guide angles are provided on the upper surfaces of the driving gear 2 and driven gear 7, and a guide angle is provided on the lower surface of the transmission gear 6. The guide angles on the driving gear 2, driven gear 7, and transmission gear 6 are consistent in both angle and lead. This ensures that after the entire detection assembly is installed, the transmission gear 6 can be smoothly guided to mesh during the installation process from top to bottom, avoiding hard contact that could cause squeezing or bumping, damaging the gears and affecting detection accuracy and reliability.

[0063] 1.2 Improvement of Shaft System Structure

[0064] Because the cable reel 1 rotates the drive shaft 5 during use, and the drive shaft 5 can become unstable and wobble during rotation, this invention improves the shaft system structure of the cable sensor to further enhance measurement accuracy. Specifically, the improvements include:

[0065] I. Such as Figure 6 As shown, the drive shaft 5 consists of a lower insertion part, a middle drive part and an upper insertion part from bottom to top. The lower insertion part and the middle drive part are provided with a lower shaft shoulder at the connection point. The middle drive part is provided with an annular groove for installing a retaining ring near the lower shaft shoulder. The middle drive part and the upper insertion part are provided with an upper shaft shoulder at the connection point.

[0066] II. A circular pin hole is radially opened on the central transmission part of the transmission shaft 5. The transmission pin 14 passes through the pin hole on the transmission shaft 5 and is installed from top to bottom in the U-shaped transmission pin mounting groove with the opening facing upward. The transmission pin mounting groove and the transmission pin 14 are interference fit.

[0067] III. A first bearing 23 and a sealing ring are provided at the contact position between the lower section of the transmission part of the transmission shaft 5 and the transverse partition of the coil spring fixing seat 16.

[0068] IV. A third bearing 25 and a shaft seal 26 are provided at the contact position between the upper section of the transmission part of the transmission shaft 5 and the center opening of the PCB board fixing seat 17.

[0069] V. An annular protrusion is integrally formed on the lower surface of the transmission part of the winding reel 1. The contact position between the transverse partition of the coil spring fixing seat 16 and the transmission part in the transmission shaft 5 is improved into a Z-shaped structure. A second bearing 24 is provided in the space formed by the annular protrusion and the Z-shaped structure.

[0070] Based on the above improvements, the stability of the drive shaft 5 during rotation can be greatly improved by using three bearings, a Z-shaped structure, and annular protrusions, thus preventing it from shaking and affecting measurement accuracy and consistency.

[0071] 1.3 Adjustments to other structures

[0072] In addition to improvements to the overall structural design of the measuring component and the shaft system, this invention also includes adjustments to other structures, resulting in a more accurate and easier-to-install cable-stayed sensor product. Figure 2 As shown, it specifically includes:

[0073] Considering the installation process, eight first threaded holes are evenly distributed circumferentially along the outer edge of the base plate 18 of the pull rope sensor housing. Eight second threaded holes are evenly distributed circumferentially along the outer side of the outer edge plate of the coil spring fixing seat 16. The positions of the second threaded holes correspond to the first threaded holes, and both the upper and lower ends of the second threaded holes are provided with internal threads. The eight first threaded holes of the base plate 18 are fixedly connected to the coil spring fixing seat 16 by screws engaging with the lower ends of the second threaded holes. Four third threaded holes are evenly distributed circumferentially along the outer side of the outer edge of the PCB board fixing seat 17 for fixed connection with the upper ends of the second threaded holes of the coil spring fixing seat 16. The bottom outer edge of the housing cover 20 is uniformly provided with four fourth threaded holes along the circumference for fixing to the upper port of the second threaded hole of the coil spring fixing seat 16. The four third threaded holes and the four fourth threaded holes are staggered, corresponding to the upper ports of a total of eight second threaded holes. This allows the housing base plate 18 to be fixed to the bottom of the outer edge plate of the coil spring fixing seat 16 after the coil spring 13 is assembled. Then, after the winding wheel 1 is assembled, the PCB board fixing seat 17 is fixed to the top of the outer edge plate of the coil spring fixing seat 16. Finally, after the detection component and the transmission gear 6 are assembled, the housing cover 20 is fixed to the top of the outer edge plate of the coil spring fixing seat 16.

[0074] It should be noted that, in order to ensure that the transmission shaft 5 is vertically installed at the center of the housing and does not cause eccentricity, the diameter of the second threaded hole is smaller than that of the first, third and fourth threaded holes. After the transmission shaft 5 is positioned by bearings, the position of the threaded hole is left with a margin for adjustment during housing assembly.

[0075] In addition, to ensure that moisture in the winding reel compartment can be discharged smoothly, multiple vent holes are opened circumferentially on the outer side of the housing. This ensures that moisture can be discharged smoothly from the winding reel compartment, reducing the humidity inside the winding reel compartment and preventing moisture from corroding the wire rope, which would lead to poor consistency and thus affect the service life and testing accuracy.

[0076] 2) Overall external calibration of the detection components:

[0077] In this invention, the accuracy (precision) of the low-cost, low-precision Hall chip, which is the core component for angle measurement, is generally [insert value here]. This differs significantly from the requirements of high-precision products. Therefore, it is necessary to calibrate the low-precision chip externally before installing it into the electronic compartment. However, the Hall chip calibrated on the fixture will inevitably become misaligned during the reinstallation process in the electronic compartment, leading to a decrease in calibration effectiveness and potentially causing the calibration process to fail. Therefore, the relative positions of the Hall chip and the corresponding magnet must be fixed in advance during calibration on the fixture. Based on this, the present invention creatively constructs a detection component consisting of a PCB board 11 with a low-cost Hall chip, a mounting bracket 12, a drive gear 2 with a first magnet 3, and a driven gear 7 with a second magnet 9. It is used as a whole component during external detection and installation and can be regarded as a prefabricated assembly during assembly. In this way, during mass production, while waiting for other components, the calibrated detection component can be prepared in advance as a prefabricated assembly, which can also effectively improve production efficiency.

[0078] like Figure 7 As shown, the entire detection component is externally calibrated using a corresponding calibration fixture. This calibration fixture mainly includes a base, a motor, a rotating gear mounted on the motor output end (the number of teeth and radius are the same as the transmission gear 6, and its lower surface also has a guide angle), and a calibration PC. The specific calibration steps are as follows:

[0079] 21) Fix the entire testing component to be calibrated on the base of the calibration fixture and adjust its horizontal position;

[0080] 22) Rotate the handwheel to adjust the height of the motor, which in turn drives the rotating gear to move from top to bottom, so that the rotating gear meshes with the driving gear 2 and the driven gear 7 at the same time;

[0081] 23) The motor drives the rotating gear component to rotate at a set speed (300 rpm in this example) by controlling the calibration PC. During the rotation within a set time (e.g., 1 minute), the average value of multiple preset angle calibration points is taken sequentially for calibration. The linear interpolation method is used to complete the calibration of the angle between two adjacent length calibration points, thereby improving the accuracy of the chip and reducing measurement error.

[0082] 3) Structural assembly of the pull-rope sensor;

[0083] After externally calibrating the entire detection component, the entire detection component is used as an assembly part to complete the assembly process of the drawstring sensor product, which specifically includes the following steps:

[0084] 31) Assemble the winding reel: Assemble the drive pin 14 and the sealing ring onto the drive shaft 5, and then pass the drive pin 14 through the center hole of the winding reel 1 from top to bottom and install it in the drive pin mounting groove by interference fit to form the winding reel accessory.

[0085] 32) Installing the coil spring: First, install the second bearing 24 on the coil spring fixing seat 16; then, install the winding reel accessory from top to bottom on the coil spring fixing seat 16, so that the second bearing 24 is stably installed in the space formed by the annular protrusion and the Z-shaped structure; next, flip the coil spring fixing seat 16 with the winding reel accessory, and after installing the first bearing 23 and the fixing retaining ring on the drive shaft 5, install the rotating sleeve 21, hook the inner hook of the coil spring 13 onto the rotating sleeve 21, and hook the outer hook into the groove of the lower outer edge plate of the coil spring fixing seat 16, and pour in lubricating oil; finally, fix the housing bottom plate to the coil spring fixing seat 16 with screws;

[0086] 33) Winding the wire rope: First, pre-tighten the coil spring 13 to the first set number of turns N in the forward direction. Then, tie one end of the wire rope to the winding wheel 1 and loosen the coil spring 13 in the reverse direction to the second set number of turns M (N>M). During this process, wind the wire rope onto the winding wheel 1 and set a pull ring at the other end of the wire rope.

[0087] 34) Install PCB board mounting bracket 17: After installing shaft seal 26 on the bottom surface of PCB board mounting bracket 17, it is sleeved on drive shaft 5, and then the third bearing 25 is installed. After ensuring that drive shaft 5 is vertically installed in the center position inside the housing, PCB board mounting bracket 17 is fixed on coil spring mounting bracket 16 with screws.

[0088] 35) Install the calibrated detection assembly: Fix the mounting bracket 12 of the detection assembly to the PCB board mounting base 17 with screws, then install the transmission gear 6 on the top of the transmission shaft 5 with fixing screws 15 so that the transmission gear 6 is fully engaged with the driving gear 2 and the driven gear 7 respectively. Install the connector 19 on the housing cover 20 and connect it to the PCB board 11 with a cable. Finally, fix the housing cover 20 to the coil spring mounting base 16 with screws to complete the structural assembly process of the current pull rope sensor product.

[0089] 4) Length calibration;

[0090] To ensure that the measured output length of the draw rope sensor corresponds to the angles of the driving and driven gears and maintains good linearity, length calibration is required after structural assembly. Specifically:

[0091] The drawstring sensor product to be calibrated and the motor are fixed on the calibration fixture. The pull ring is fitted onto the motor output shaft. The motor rotation drives the pull ring of the drawstring sensor to pull out the steel wire rope. A high-precision magnetic encoder for calibration is placed between the motor and the drawstring sensor product to be calibrated (in this example, the accuracy of the high-precision magnetic encoder is...). (Even higher) is used to determine the specific length of the wire rope being pulled out. When the motor rotates and drives the wire rope to be pulled out, the magnetic encoder detects that the length of the wire rope pulled out is the set length calibration point ln (generally, multiple points are set within the range, and the higher the accuracy requirement, the more points are set). The angles of the driving gear and driven gear corresponding to the length calibration point ln are recorded as the calibrated angles. Finally, the multi-segment linear interpolation method is used to determine the calibration data between two adjacent length calibration points to complete the calibration.

[0092] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. A method for manufacturing and assembling a high-precision draw rope sensor, characterized in that, Includes the following steps: 1) The structure of the pull-rope sensor has been improved to meet the requirements of low cost and high precision; 2) External calibration of the entire testing component; 3) Structural assembly of the pull-rope sensor; 4) Length calibration.

2. The production and assembly method of a high-precision draw rope sensor according to claim 1, characterized in that, In step 1), the structural improvement of the rope sensor specifically includes the overall structural design of the measurement component, the improvement of the shaft system structure, and the adjustment of other structures.

3. The production and assembly method of a high-precision draw rope sensor according to claim 2, characterized in that, The overall structural design of the measurement component is specifically to construct a detection component consisting of a PCB board with a Hall chip, a mounting bracket, a drive gear with a first magnet, and a driven gear with a second magnet.

4. The production and assembly method of a high-precision draw rope sensor according to claim 3, characterized in that, In the overall measuring component, a circular mounting hole is provided in the middle of the fixed frame to avoid the installation of the transmission gear. On the left and right sides of the circular mounting hole, a driving gear and a driven gear are rotatably mounted via a rotating shaft. A first magnet and a magnetic shielding ring are fixedly mounted on the driving gear, and a second magnet and a magnetic shielding ring are fixedly mounted on the driven gear. The driving gear and the driven gear mesh with the transmission gear on the left and right sides respectively, and all three have the same module. The number of teeth and radius of the driving gear are smaller than those of the driven gear. The PCB board is fixed on the fixed frame. On the lower surface of the PCB board, one first Hall chip and one second Hall chip are respectively provided at the positions directly opposite the first magnet and the second magnet. In addition, a mounting hole is provided on the PCB board at the position corresponding to the installation of the transmission gear to avoid the transmission gear.

5. The production and assembly method of a high-precision draw rope sensor according to claim 4, characterized in that, To achieve redundant measurement, two first Hall chips and two second Hall chips are respectively installed on the upper and lower surfaces of the PCB board at positions directly opposite the first and second magnets.

6. The production and assembly method of a high-precision draw rope sensor according to claim 2, characterized in that, The improvements to the shaft system structure are as follows: An annular groove for mounting and fixing retaining rings is provided in the transmission part of the transmission shaft near the lower shoulder. A circular pin hole is opened radially in the transmission part of the transmission shaft. After the transmission pin passes through the pin hole on the transmission shaft, it is installed from top to bottom in the U-shaped transmission pin mounting groove with the opening facing upward. The transmission pin mounting groove and the transmission pin are interference fit. A first bearing and a sealing ring are provided at the contact position between the lower section of the transmission part and the transverse partition of the coil spring fixing seat in the transmission shaft; A third bearing and shaft seal are provided at the contact position between the upper section of the transmission part and the center opening of the PCB board mounting base in the transmission shaft. An annular protrusion is integrally formed on the lower surface of the drive section of the winding reel. The contact position between the transverse partition of the coil spring fixing seat and the drive section in the drive shaft is set in a Z-shaped structure. A second bearing is provided in the space formed by the annular protrusion and the Z-shaped structure.

7. The production and assembly method of a high-precision draw rope sensor according to claim 2, characterized in that, The adjustments to the other structures are as follows: A first threaded hole is uniformly provided circumferentially on the outer edge of the bottom plate of the housing of the pull rope sensor. A second threaded hole is uniformly provided circumferentially on the outer side of the outer edge plate of the coil spring fixing seat. Both the upper and lower ends of the second threaded hole are provided with internal threads. The first threaded hole of the housing bottom plate is fixedly connected to the coil spring fixing seat 16 by screws cooperating with the lower end of the second threaded hole. The outer side of the outer edge of the PCB board mounting base is uniformly provided with a third threaded hole for fixed connection with the upper port of the second threaded hole of the coil spring mounting base 16. The outer edge of the bottom of the housing cover is uniformly provided with a fourth threaded hole for fixed connection with the upper port of the second threaded hole of the coil spring mounting base. The third threaded hole and the fourth threaded hole are staggered and correspond to the upper port of the second threaded hole respectively. Multiple vent holes are opened circumferentially on the outer side of the casing.

8. The production and assembly method of a high-precision draw rope sensor according to claim 1, characterized in that, Step 2) specifically includes the following steps: 21) Fix the entire detection component to be calibrated on the base of the calibration fixture and adjust its horizontal position; 22) Adjust the height of the motor, thereby driving the rotating gear to move from top to bottom so that the rotating gear meshes with both the driving gear and the driven gear at the same time; 23) The motor drives the rotating gear component to rotate at a set speed by controlling the calibration PC. During the rotation process within a set time, the average value of multiple preset angle calibration points is taken sequentially, and the angle between two adjacent length calibration points is calibrated by using linear interpolation.

9. The production and assembly method of a high-precision draw rope sensor according to claim 1, characterized in that, Step 3) specifically includes the following steps: 31) Assemble the winding reel: Assemble the drive pin and sealing ring onto the drive shaft, pass them from top to bottom through the center hole of the winding reel, and then use an interference fit to install the drive pin in the drive pin mounting groove to form the winding reel accessory; 32) Installing the coil spring: First, install the second bearing on the coil spring mounting base; then, install the winding reel accessory from top to bottom on the coil spring mounting base, so that the second bearing is installed in the space formed by the annular protrusion and the Z-shaped structure; next, flip the coil spring mounting base with the winding reel accessory, and after installing the first bearing and the retaining ring on the drive shaft, install the rotating sleeve, install the coil spring and fill it with lubricating oil; finally, fix the housing base plate to the coil spring mounting base with screws; 33) Winding the wire rope: First, pre-tighten the spring in the forward direction to the first set number of turns N, then tie one end of the wire rope to the winding wheel, and loosen the spring in the reverse direction to the second set number of turns M (N>M). During this process, the wire rope is wound on the winding wheel, and a pull ring is set at the other end of the wire rope. 34) Install PCB board mounting bracket: After installing the shaft seal on the bottom surface of the PCB board mounting bracket, put it on the drive shaft, and then install the third bearing. After ensuring that the drive shaft is vertically installed in the center position inside the housing, fix the PCB board mounting bracket to the coil spring mounting bracket with screws. 35) Install the calibrated detection assembly: Fix the mounting bracket in the detection assembly to the PCB board mounting base, then install the transmission gear on the top of the transmission shaft and make the transmission gear fully mesh with the driving gear and the driven gear respectively. Install the connector on the housing cover and connect it to the PCB board through the cable. Finally, fix the housing cover to the coil spring mounting base to complete the structural assembly process of the current pull rope sensor product.

10. The production and assembly method of a high-precision draw rope sensor according to claim 1, characterized in that, Step 4) specifically includes the following steps: The pull rope sensor product to be calibrated and the motor are fixed on the calibration fixture. The pull ring is sleeved on the output shaft of the motor. The rotation of the motor drives the pull ring of the pull rope sensor to pull out the wire rope. A calibration magnetic encoder is set between the motor and the pull rope sensor product to be calibrated to detect the length of the wire rope being pulled out. When the motor rotates and the wire rope is pulled out, if the magnetic encoder detects that the length of the wire rope pulled out is the set length calibration point ln, the angles of the driving gear and driven gear corresponding to the length calibration point ln are recorded as the calibrated angles. Finally, the calibration data between two adjacent length calibration points is determined by multi-segment linear interpolation, and the calibration is completed.

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