A screw tightening device and a screw point position automatic recognition positioning device and method thereof

Abstract

The application discloses a screw tightening device and a screw point position automatic identification positioning device and method thereof, and belongs to the technical field of screw tightening. The device comprises an auxiliary moving mechanism connected with a tightening gun assembly, a linear displacement sensor and an angle displacement sensor arranged on the auxiliary moving mechanism, and a control mechanism; the linear displacement sensor is used for detecting the extension displacement of the tightening gun assembly in real time; the angle displacement sensor is used for detecting the rotation angle of the tightening gun assembly in real time; and the control mechanism is used for collecting detection data to obtain the actual space coordinates of the tightening gun assembly, so that automatic positioning identification of the screw corresponding to the tightening gun assembly is realized. The actual space coordinates of the tightening gun assembly can be obtained in real time through the double-displacement sensor setting, automatic identification positioning of the screw point position is completed, reliable support is provided for automatic tightening operation of the tightening gun, the structure is simple, the result is accurate and reliable, the mistake-proofing capability and production efficiency of screw tightening are improved, and the labor intensity of post personnel is reduced.

Description

Technical Field

[0001] This invention relates to the field of automatic screw tightening technology, and in particular to a screw tightening device and its automatic screw position identification and positioning device and method. Background Technology

[0002] At the transfer case housing screw tightening station, the original operation involved manually moving the tightening gun assembly above the screws on the workpiece. The operator then manually selected the screw location on the touch control screen, and the tightening gun assembly tightened the corresponding screw and uploaded the tightening data. This method was cumbersome and physically demanding, as each workpiece typically contained multiple screws, requiring multiple manual clicks for each product. More importantly, it was prone to human error and omissions, resulting in the inability to upload tightening data, triggering equipment alarms and shutdowns, and impacting production cycle time.

[0003] Furthermore, the traditional operating method relies solely on pre-set program points, without any actual physical position verification during the process. When the tightening gun deviates or the tooling rotates slightly, the system cannot identify the actual screw position, easily leading to quality risks such as misaligned or incorrect screw installation. To address these existing problems, a visual positioning solution is currently used for actual physical position verification, but visual positioning equipment is expensive. Moreover, the tightening workspace is confined, and oil stains easily contaminate the lens, resulting in a large workload for daily maintenance and making it difficult to adapt to long-term mass production conditions in the workshop. If mechanical structure optimization positioning is adopted, it requires significant disassembly and modification of the tooling, resulting in high modification costs and long downtime for debugging.

[0004] In view of this, this application creates a brand-new screw tightening device and its automatic screw position identification and positioning device and method, which can easily overcome the shortcomings of existing tightening stations that rely on manual selection of screw positions, cannot compensate for tooling rotation deviation due to purely program-preset positions, and have high costs for mechanical tooling modification. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide an automatic screw position identification and positioning device, which can automatically identify the current screw position through the composite detection of linear displacement and angular displacement by dual sensors, providing reliable support for the automatic tightening operation of the tightening gun, improving the error prevention capability and production efficiency of screw tightening, reducing the labor intensity of the operator, and thus overcoming the shortcomings of the existing screw tightening devices.

[0006] To address the aforementioned technical problems, this invention provides an automatic screw position identification and positioning device for use in conjunction with a tightening gun assembly to achieve screw positioning. The device includes an auxiliary moving mechanism connected to the tightening gun assembly, a linear displacement sensor and an angular displacement sensor mounted on the auxiliary moving mechanism, and a control mechanism connected to the tightening gun assembly, the linear displacement sensor, and the angular displacement sensor.

[0007] The auxiliary moving mechanism includes a fixed shaft, a rotary table, and a telescopic optical shaft. The telescopic optical shaft is slidably mounted on the rotary table, and the rotary table is rotatably mounted on the fixed shaft. The telescopic direction of the telescopic optical shaft is perpendicular to the fixed shaft. One end of the telescopic optical shaft is fixedly connected to the tightening gun assembly. Under the action of the rotary table and the telescopic optical shaft, the tightening gun assembly can achieve the correspondence of several screw points on its corresponding workpiece.

[0008] The linear displacement sensor is located on the side of the rotary table and is used to detect the extension displacement of the telescopic optical shaft in real time, thereby obtaining the extension displacement of the tightening gun assembly.

[0009] The angle displacement sensor is located on the upper part of the rotary table and is used to detect the rotation angle of the rotary table in real time, thereby obtaining the rotation angle of the tightening gun assembly.

[0010] The control mechanism is used to collect the detection data of the linear displacement sensor and the angular displacement sensor in real time, obtain the actual spatial coordinates of the tightening gun assembly, and realize the automatic positioning and identification of the screw corresponding to the tightening gun assembly based on the actual spatial coordinates of the tightening gun assembly.

[0011] In a further improvement, the linear displacement sensor is a wire-type displacement sensor, the main body of which is fixed on the rotating platform, and the wire end of which is connected to the tightening gun assembly.

[0012] As a further improvement, the angular displacement sensor adopts an electronic compass.

[0013] As a further improvement, the control mechanism adopts a PLC controller.

[0014] In a further improvement, the telescopic optical axis comprises two axes, which are symmetrically arranged on both sides of the fixed axis.

[0015] As a further improvement of the present invention, the present invention also provides a screw tightening device. This screw tightening device includes a tightening gun assembly and the aforementioned automatic screw position identification and positioning device, wherein the tightening gun assembly is connected to the control mechanism.

[0016] As another improvement of the present invention, the present invention also provides an automatic screw positioning and tightening method. The method employs the aforementioned screw tightening device and specifically includes the following steps:

[0017] S1. Pre-enter the standard theoretical spatial coordinates of all screws on the workpiece, as well as the tightening process parameters corresponding to all screws, and establish a screw coordinate database;

[0018] S2. The equipment is started. The tightening gun assembly moves to the position corresponding to the first screw under manual operation. The linear displacement sensor transmits the extension distance signal of the tightening gun assembly and the angular displacement sensor transmits the rotation angle signal of the tightening gun assembly to the control mechanism simultaneously.

[0019] S3. After the control mechanism collects the extension distance signal and rotation angle signal of the tightening gun assembly, it obtains the real-time spatial coordinates of the tightening gun assembly;

[0020] S4. Compare the real-time spatial coordinates of the tightening gun assembly with the screw coordinates in the screw coordinate database. If the difference is within the preset error threshold range, automatically match the corresponding screw position and proceed to step S5; if it is not within the preset error threshold range, determine that the position is abnormal and issue an alarm signal.

[0021] S5. The control mechanism retrieves the automatically matched tightening process parameters of the corresponding screw position from the screw coordinate database and transmits them to the tightening gun assembly, which then completes the tightening operation of the screw.

[0022] S6. After tightening, upload the screw tightening data;

[0023] S7. Repeat steps S2-S6 until all screws on the workpiece are tightened.

[0024] Further improvements include tightening torque and tightening angle parameters.

[0025] Further improvements include tightening torque and tightening angle parameters.

[0026] In a further improvement, the preset error thresholds in step S4 include a preset error threshold for linear displacement and a preset error threshold for angular displacement.

[0027] Further improvements include setting the preset error threshold for linear displacement to ±20mm and the preset error threshold for angular displacement to ±5°.

[0028] With this design, the present invention has at least the following advantages:

[0029] The automatic screw position identification and positioning device of this invention, by setting up dual displacement sensors for real-time detection of the linear and angular displacement of the tightening gun assembly, can obtain the actual spatial coordinates of the tightening gun assembly in real time, and complete the automatic identification and positioning of the screw position. This provides reliable support for the automatic tightening operation of the tightening gun, eliminating the need for manual operation to select the position in traditional methods and eliminating the need for major modifications to the original tooling. It greatly improves the error prevention capability and production efficiency of screw tightening, and reduces the labor intensity of the personnel on duty.

[0030] The automatic screw position identification and positioning device of the present invention has a simple structure and accurate and reliable results, providing a reliable guarantee for the accurate operation of screw tightening devices.

[0031] The automatic screw positioning and tightening method of this invention is based on dual displacement sensors in the automatic screw position identification and positioning device. It simply and conveniently solves the problem of displacement space positioning of the tightening gun assembly in actual work. Combined with the screw theoretical coordinate database, the corresponding screw position can be quickly matched by comparing the two, or the position abnormality can be detected in time and an alarm signal can be issued to avoid accidents, improve safety, and improve the error prevention capability and production efficiency of screw tightening. Attached Figure Description

[0032] The above is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0033] Figure 1 This is a schematic diagram of the screw tightening device of the present invention.

[0034] Figure 2 This is a flowchart of the automatic screw positioning and tightening method of the screw tightening device of the present invention. Detailed Implementation

[0035] Exemplary embodiments of the invention will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the invention are shown in the drawings, it should be understood that the invention may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of the invention and to fully convey the scope of the invention to those skilled in the art.

[0036] See attached document Figure 1 As shown, the screw tightening device in this embodiment includes a tightening gun assembly 1 and an automatic screw position identification and positioning device 2 connected thereto.

[0037] In this embodiment, the tightening gun assembly 1 adopts the existing tightening gun assembly structure, which can realize the automatic tightening of screws.

[0038] The automatic screw position identification and positioning device 2 described in this embodiment includes an auxiliary moving mechanism 21 connected to the tightening gun assembly 1, a linear displacement sensor 22 and an angular displacement sensor 23 disposed on the auxiliary moving mechanism 21, and a control mechanism 24 connected to the tightening gun assembly 1, the linear displacement sensor 22, and the angular displacement sensor 23.

[0039] Specifically, the auxiliary moving mechanism 21 includes a fixed shaft 211, a rotating platform 212, and a telescopic optical shaft 213. The telescopic optical shaft 213 is slidably mounted on the rotating platform 212, and the rotating platform 212 is rotatably mounted on the fixed shaft 211. The telescopic direction of the telescopic optical shaft 213 is perpendicular to the fixed shaft 211. In this embodiment, the fixed shaft 211 is vertically mounted, and the telescopic optical shaft 213 extends and retracts horizontally. One end of the telescopic optical shaft 213 is fixedly connected to the tightening gun assembly 1, and the other end slides horizontally in the rotating platform 212. Thus, under the action of the rotating platform 212 and the telescopic optical shaft 213, the tightening gun assembly 1 can achieve positional positioning within a circumferential area around the fixed shaft 211, corresponding to several screw points on its workpiece.

[0040] In this embodiment, the linear displacement sensor 22 is disposed on the side of the rotary table 212 to detect the extension displacement of the telescopic optical shaft 213 in real time, thereby determining the horizontal extension displacement of the tightening gun assembly 1. Specifically, the linear displacement sensor 22 is a wire-type displacement sensor, the main body of which is fixed on the rotary table 212, and its wire end is connected to the tightening gun assembly 1. When the tightening gun assembly 1 extends horizontally, the wire end is pulled out, thereby detecting the extension displacement.

[0041] In this embodiment, the angle displacement sensor 23 is disposed on the upper part of the rotary table 212 to detect the rotation angle of the rotary table 212 in real time, thereby determining the rotation angle of the tightening gun assembly 1. Specifically, the angle displacement sensor 23 uses an electronic compass to detect the angle displacement signal.

[0042] In this embodiment, the control mechanism 24 is used to collect the detection data of the linear displacement sensor 22 and the angular displacement sensor 23 in real time, obtain the actual spatial coordinates of the tightening gun assembly 1, and then realize the automatic positioning and identification of the screw corresponding to the tightening gun assembly 1 based on the actual spatial coordinates of the tightening gun assembly 1, that is, automatically match the corresponding screw position based on the actual spatial coordinates of the tightening gun assembly 1. Specifically, the control mechanism adopts a PLC controller. The angular displacement signal of the electronic compass is connected to the Ethernet port of the PLC controller through a Modbus gateway, and the extension displacement signal of the displacement sensor is connected to the analog signal acquisition module of the PLC controller. The PLC controller also has a pre-stored screw theoretical coordinate database module, which is used to store the standard theoretical spatial coordinates of all screws on the workpiece, as well as the tightening process parameters corresponding to all screws.

[0043] In this embodiment, the telescopic optical shaft 213 includes two shafts, which are symmetrically arranged on both sides of the fixed shaft 211, so as to better and more stably connect the tightening gun assembly 1.

[0044] See attached document Figure 2 As shown, the aforementioned screw tightening device, based on its automatic screw position identification and positioning device, can complete the automatic positioning and tightening operation of screws. The specific method includes the following steps:

[0045] S1. Preliminary calibration: Pre-enter the standard theoretical spatial coordinates of all screws on the workpiece, as well as the tightening process parameters corresponding to all screws, and establish a screw coordinate database.

[0046] S2. The device is started. The tightening gun assembly 1 is moved to the position corresponding to the first screw under human action. The linear displacement sensor 22 transmits the extension distance signal of the tightening gun assembly 1 and the angular displacement sensor 23 transmits the rotation angle signal of the tightening gun assembly 1 to the control mechanism 24 simultaneously.

[0047] S3. After the control mechanism 24 collects the extension distance signal and rotation angle signal of the tightening gun assembly 1, it obtains the real-time spatial coordinates of the tightening gun assembly 1.

[0048] S4. Compare the real-time spatial coordinates of the tightening gun assembly 1 with the screw coordinates in the screw coordinate database. If the difference is within the preset error threshold range, automatically match the corresponding screw position and proceed to step S5; if it is not within the preset error threshold range, determine that the position is abnormal and issue an alarm signal.

[0049] The preset error thresholds include a linear displacement preset error threshold and an angular displacement preset error threshold. The linear displacement preset error threshold is ±20mm, and the angular displacement preset error threshold is ±5°.

[0050] S5. The control mechanism 24 retrieves the automatically matched tightening process parameters of the corresponding screw position from the screw coordinate database, such as tightening torque and tightening angle, and transmits them to the tightening gun assembly 1, which then completes the tightening operation of the screw.

[0051] S6. After tightening, upload the screw tightening data.

[0052] S7. Repeat steps S2-S6 until all screws on the workpiece are tightened.

[0053] The automatic screw position identification and positioning method of this invention's screw tightening device obtains the true spatial coordinates of the screw through real-time detection of dual sensor signals, unaffected by slight tooling offsets, resulting in higher positioning reliability. It is also highly adaptable; when switching between different types of housing screws at the same workstation, only the coordinate calculation parameters need to be modified, eliminating the need to rearrange a large number of sensors. Furthermore, it promptly issues an alarm signal when an abnormal position is detected, preventing incorrect or missed screw tightening, thus providing strong quality error prevention capabilities. This method eliminates the need for manual position selection, saving multiple touchscreen clicks, simplifying employee workflows, improving production efficiency, and reducing the probability of human error.

[0054] The automatic screw position identification and positioning device of this invention has low modification cost. It does not require extensive disassembly and structural modification of the original tooling. It can be implemented simply by adding sensors and supporting circuits, thus avoiding the material costs and production line downtime modification costs caused by major tooling overhauls.

[0055] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications, equivalent changes, or alterations made by those skilled in the art using the disclosed technical content shall fall within the protection scope of the present invention.

Claims

1. An automatic screw position identification and positioning device, used in conjunction with a tightening gun assembly to achieve screw positioning, characterized in that, It includes an auxiliary moving mechanism connected to the tightening gun assembly, a linear displacement sensor and an angular displacement sensor disposed on the auxiliary moving mechanism, and a control mechanism connected to the tightening gun assembly, the linear displacement sensor and the angular displacement sensor; The auxiliary moving mechanism includes a fixed shaft, a rotary table, and a telescopic optical shaft. The telescopic optical shaft is slidably mounted on the rotary table, and the rotary table is rotatably mounted on the fixed shaft. The telescopic direction of the telescopic optical shaft is perpendicular to the fixed shaft. One end of the telescopic optical shaft is fixedly connected to the tightening gun assembly. Under the action of the rotary table and the telescopic optical shaft, the tightening gun assembly can achieve the correspondence of several screw points on its corresponding workpiece. The linear displacement sensor is located on the side of the rotary table and is used to detect the extension displacement of the telescopic optical shaft in real time, thereby obtaining the extension displacement of the tightening gun assembly. The angle displacement sensor is located on the upper part of the rotary table and is used to detect the rotation angle of the rotary table in real time, thereby obtaining the rotation angle of the tightening gun assembly. The control mechanism is used to collect the detection data of the linear displacement sensor and the angular displacement sensor in real time, obtain the actual spatial coordinates of the tightening gun assembly, and realize the automatic positioning and identification of the screw corresponding to the tightening gun assembly based on the actual spatial coordinates of the tightening gun assembly.

2. The automatic screw position identification and positioning device according to claim 1, characterized in that, The linear displacement sensor is a wire-type displacement sensor, the main body of which is fixed on the rotating table, and the wire end is connected to the tightening gun assembly.

3. The automatic screw position identification and positioning device according to claim 2, characterized in that, The angular displacement sensor uses an electronic compass.

4. The automatic screw position identification and positioning device according to claim 3, characterized in that, The control mechanism uses a PLC controller.

5. The automatic screw position identification and positioning device according to any one of claims 1 to 4, characterized in that, The telescopic optical axis comprises two axes, which are symmetrically arranged on both sides of the fixed axis.

6. A screw tightening device, characterized in that, It includes a tightening gun assembly and an automatic screw position identification and positioning device as described in any one of claims 1 to 5, wherein the tightening gun assembly is connected to the control mechanism.

7. A method for automatically positioning and tightening screws, characterized in that, The method using the screw tightening device of claim 6 includes the following steps: S1. Pre-enter the standard theoretical spatial coordinates of all screws on the workpiece, as well as the tightening process parameters corresponding to all screws, and establish a screw coordinate database; S2. The equipment is started. The tightening gun assembly moves to the position corresponding to the first screw under manual operation. The linear displacement sensor transmits the extension distance signal of the tightening gun assembly and the angular displacement sensor transmits the rotation angle signal of the tightening gun assembly to the control mechanism simultaneously. S3. After the control mechanism collects the extension distance signal and rotation angle signal of the tightening gun assembly, it obtains the real-time spatial coordinates of the tightening gun assembly; S4. Compare the real-time spatial coordinates of the tightening gun assembly with the screw coordinates in the screw coordinate database. If the difference is within the preset error threshold range, automatically match the corresponding screw position and proceed to step S5; if it is not within the preset error threshold range, determine that the position is abnormal and issue an alarm signal. S5. The control mechanism retrieves the automatically matched tightening process parameters of the corresponding screw position from the screw coordinate database and transmits them to the tightening gun assembly, which then completes the tightening operation of the screw. S6. After tightening, upload the screw tightening data; S7. Repeat steps S2-S6 until all screws on the workpiece are tightened.

8. The automatic screw positioning and tightening method according to claim 7, characterized in that, The tightening process parameters include tightening torque and tightening angle parameters.

9. The automatic screw positioning and tightening method according to claim 7, characterized in that, The preset error thresholds in step S4 include the preset error threshold for linear displacement and the preset error threshold for angular displacement.

10. The automatic screw positioning and tightening method according to claim 9, characterized in that, The preset error threshold for linear displacement is ±20mm, and the preset error threshold for angular displacement is ±5°.

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