Detection positioning mechanism applied to welding of internal nut plate

Abstract

The utility model relates to the technical field of body-in-white welding, and discloses a detecting and positioning mechanism applied to internal nut plate welding, which comprises a positioning component, a detecting component and a control unit, the positioning component and the detecting component are both electrically connected with the control unit, and the positioning component comprises a positioning pin, a locking mechanism and a positioning guide sleeve. The detection assembly comprises a displacement double-nut locking structure, a proximity switch and a proximity switch protection sleeve. The control unit comprises a sensor signal lamp and an upper signal and PLC signal detection control module. According to the detecting and positioning mechanism applied to welding of the internal nut plate, the positioning assembly and the detecting assembly are integrated into the same mechanism, the problems of over-positioning and missing welding of a traditional positioning mode are solved, the defect that the position of a nut cannot be guaranteed is overcome, one-time positioning and double detection are achieved, the tool structure is simplified, and the occupied area of equipment is reduced.

Description

Technical Field

[0001] This utility model belongs to the field of body-in-white welding technology, specifically, it relates to a detection and positioning mechanism applied to the welding of internal nut plates. Background Technology

[0002] In the passenger vehicle manufacturing industry, passenger vehicle seat mounting brackets are typically formed by welding an outer contour component (self-welded) to an internally projected nut plate. During the welding process, it is crucial to strictly ensure not only the overall dimensions of the product and the flatness of the upper mounting surface, but also the position of the nut within the nut hole to meet subsequent assembly requirements. However, the positioning methods used in existing technologies have significant drawbacks, making it difficult to simultaneously achieve positioning accuracy, ease of component handling, and prevention of incomplete welds. Specific problems are as follows:

[0003] The traditional positioning method has several drawbacks: it uses the product's main and auxiliary positioning holes and adds an additional fixing and positioning structure to ensure the accuracy of the nut holes. However, this method, which uses three positioning pins to fix the welded parts, suffers from over-positioning. Over-positioning makes it difficult to remove the parts from the tooling fixture after welding, greatly affecting the convenience of picking up and placing parts and reducing production efficiency. At the same time, this positioning method does not have a detection switch to check the presence of the internal nut, posing a significant risk of missing nuts. If parts with missing nuts flow into subsequent processes, it will cause assembly failures, increase production costs, and create potential quality problems.

[0004] Given the aforementioned limitations of existing positioning technologies, there is an urgent need for an integrated mechanism that can simultaneously achieve precise positioning, convenient component handling, anti-missed weld detection, and nut position accuracy assurance, in order to solve the accuracy and efficiency problems in the welding process of the nut plate inside the body-in-white. Utility Model Content

[0005] The purpose of this utility model is to provide a detection and positioning mechanism for welding internal nut plates, so as to solve the problems of over-positioning, inconvenience in picking and placing parts, risk of missing welding and inability to guarantee the position accuracy of the nut in the existing positioning method in the background art, and realize the integration of positioning and detection functions to improve welding quality and production efficiency.

[0006] A detection and positioning mechanism for internal nut plate welding includes a positioning component, a detection component, and a control unit, wherein the positioning component and the detection component are electrically connected to the control unit;

[0007] The positioning assembly includes a positioning pin, a locking mechanism, and a positioning guide sleeve; the theoretical diameter accuracy of the positioning pin is greater than or equal to -0.02mm and simultaneously less than or equal to 0mm; the locking mechanism is made of 45# steel with a hardness greater than or equal to 40HRC and simultaneously less than or equal to 45HRC; the positioning guide sleeve is made of mold guide sleeve material, with a built-in graphite lubrication structure, and the clearance between it and the positioning pin is greater than or equal to 0mm and less than or equal to 0.1mm;

[0008] The detection component includes a displacement double-nut locking structure, a proximity switch, and a proximity switch protective sleeve. The mechanical grade of the displacement double-nut locking structure is not lower than 8.8. The diameter of the proximity switch is greater than or equal to 6 mm and less than or equal to 18 mm. The proximity switch protective sleeve is made of copper, and its inner diameter is 0.1 mm larger than the outer diameter of the proximity switch.

[0009] The control unit includes a sensor indicator light and a host signal and PLC signal detection and control module. The sensor indicator light is integrated into the proximity switch. The host signal and PLC signal detection and control module are respectively connected to the proximity switch and the locking mechanism.

[0010] In a preferred embodiment of this utility model, the positioning guide sleeve is fixed in the preset mounting hole of the tooling fixture, and the coaxiality deviation between the axis of the positioning guide sleeve and the axis of the positioning hole of the part does not exceed 0.05mm.

[0011] In a preferred embodiment of this utility model, the displacement double nut locking structure is used to fix the installation position of the proximity switch, and the detection reference of the proximity switch can be calibrated by finely adjusting the relative position of the double nuts.

[0012] In a preferred embodiment of this utility model, the preset logic of the control unit is as follows: after the part is clamped, the proximity switch starts detection; when the detection is qualified, a welding permission signal is sent; when the detection is abnormal, an alarm is triggered and welding is prohibited.

[0013] In a preferred embodiment of this utility model, the clamping force of the locking mechanism is adjustable, with an adjustment range of greater than or equal to 80N and simultaneously less than or equal to 120N, and the deviation of the fit with the surface of the part during clamping does not exceed 0.03mm.

[0014] In a preferred embodiment of this utility model, the proximity switch is a non-contact sensor that can simultaneously identify the presence or absence of a nut and its positional deviation by detecting changes in distance, with a detection accuracy of ±0.02mm.

[0015] In a preferred embodiment of this utility model, the sensor indicator light uses different colors to reflect the detection status: green indicates normal detection (nut is present and the position is correct), and red indicates abnormal detection (no nut or position deviation).

[0016] Compared with the prior art, the present invention has the following advantages:

[0017] 1. This detection and positioning mechanism applied to the welding of internal nut plates solves the problems of over-positioning and missed welding in traditional positioning methods by integrating the positioning component and the detection component into the same mechanism. It also makes up for the defect that the nut position accuracy cannot be guaranteed, achieving single positioning and dual detection, simplifying the tooling structure and reducing the equipment footprint.

[0018] 2. This detection and positioning mechanism, applied to the welding of internal nut plates, allows the diameter of the proximity switch to be selected according to the nut hole size of different parts. The specifications of the positioning pin and positioning guide sleeve can also be changed by replacing parts that are adapted to different main and auxiliary positioning hole sizes. This eliminates the need to redesign the entire tooling and reduces the equipment investment cost for the production of multiple types of parts.

[0019] The specific embodiments of this utility model will be described in further detail below with reference to the accompanying drawings. Attached Figure Description

[0020] In the attached diagram:

[0021] Figure 1 This is a schematic diagram of the overall structure of this utility model;

[0022] Figure 2 This is a schematic diagram of the disassembled structure of this utility model.

[0023] In the diagram: 1. Positioning pin; 2. Locking mechanism; 3. Positioning guide sleeve; 4. Displacement double nut locking structure; 5. Proximity switch; 6. Proximity switch protective sleeve; 7. Sensor indicator light; 8. Upper-level signal and PLC signal detection and control module. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions in the embodiments will be clearly and completely described below with reference to the accompanying drawings. The following embodiments are used to illustrate this utility model.

[0025] like Figures 1 to 2 As shown, a detection and positioning mechanism for welding internal nut plates includes a positioning component, a detection component, and a control unit. The positioning component and the detection component are both electrically connected to the control unit, which is used to coordinate the positioning action of the positioning component and the detection feedback of the detection component.

[0026] Positioning components: used to achieve precise positioning of parts, including positioning pin 1, locking mechanism 2, and positioning guide sleeve 3; the theoretical diameter accuracy requirement of positioning pin 1 is greater than or equal to -0.02mm and less than or equal to 0mm, used to insert into the main and auxiliary positioning holes of the part to provide a basic positioning reference; locking mechanism 2 is made of 45# steel after quenching treatment, with a hardness of greater than or equal to 40HRC and less than or equal to 45HRC, used to stably clamp the part after positioning to avoid part displacement during welding; positioning guide sleeve 3 is made of mold guide sleeve material, with a built-in graphite lubrication structure, and the fit clearance with positioning pin is greater than or equal to 0mm and less than or equal to 0.1mm, which not only ensures positioning accuracy, but also reduces wear between positioning pin 1 and positioning guide sleeve 3, and improves the smoothness of positioning action, solving the problem of inconvenience in picking up and placing parts caused by traditional over-positioning.

[0027] Detection components: Used for real-time monitoring of the presence and position of nuts, including a displacement double-nut locking structure 4, a proximity switch 5, and a proximity switch protective sleeve 6; the displacement double-nut locking structure 4 has a mechanical grade of not less than 8.8, used to fix the installation position of the proximity switch 5, and can calibrate the detection reference of the proximity switch 5 by finely adjusting the relative position of the two nuts to ensure detection accuracy; the diameter of the proximity switch 5 is selected according to the size of the nut hole of the part, ranging from greater than or equal to 6mm and less than or equal to 18mm, used for non-contact detection of the presence or absence of nuts, and can provide real-time feedback to the control unit if no nut is detected; at the same time, the detection signal of the proximity switch 5 can indirectly reflect the position of the nut, if the nut position deviates beyond the allowable range, the change in the detection distance of the proximity switch 5 will trigger a signal abnormality, realizing auxiliary monitoring of position; the proximity switch protective sleeve 6 is made of copper, and its inner diameter is 0.1mm larger than the outer diameter of the proximity switch 5, used to protect the proximity switch 5 from damage by welding spatter and high temperature, and extend its service life.

[0028] Control unit: Includes sensor indicator light 7 and host signal and PLC signal detection and control module 8; Sensor indicator light 7 is integrated into proximity switch 5 itself, and uses different colored lights to reflect the detection status, such as green indicating normal detection and red indicating no nut or abnormal position, which is convenient for operators to judge intuitively; Host signal and PLC signal detection and control module 8 establishes a communication connection with proximity switch 5 and locking mechanism 2, can receive detection signals from proximity switch 5, and control the clamping / releasing action of locking mechanism 2 according to preset logic; If an abnormality is detected, such as no nut or position deviation, the module can immediately trigger an alarm signal and suspend the welding process to prevent unqualified parts from flowing into subsequent stages.

[0029] Component assembly process:

[0030] Fix the positioning guide sleeve 3 into the preset mounting hole of the tooling fixture, ensuring that the axis of the positioning guide sleeve 3 is coaxial with the axis of the positioning hole of the part; insert the positioning pin 1 into the positioning guide sleeve 3 and test the smoothness of insertion and removal of the positioning pin 1. Since the positioning guide sleeve 3 has built-in graphite lubrication, the insertion and removal resistance should be less than 5N; finally, install the locking mechanism 2 on the side of the positioning pin 1, adjust the clamping stroke to ensure that it can fit against the outer surface of the part when clamping, and control the clamping force to be greater than or equal to 80N and less than or equal to 120N at the same time to avoid damaging the surface of the part.

[0031] Weld the proximity switch protective sleeve 6 directly below the corresponding nut hole of the tooling fixture, ensuring that the deviation between the axis of the proximity switch protective sleeve 6 and the axis of the nut hole does not exceed 0.05mm; insert the proximity switch 5 into the proximity switch protective sleeve 6, and fix the position of the proximity switch 5 by the displacement double nut locking structure 4. At this time, the detection distance of the proximity switch 5 needs to be calibrated—install the standard nut (position accuracy qualified) on the simulation part, adjust the height of the proximity switch 5 so that the sensor indicator light 7 shows green (normal detection state), and record the position of the double nut as the benchmark for subsequent mass production.

[0032] Connect the host signal and PLC signal detection and control module 8 to the drive motors of the proximity switch 5 and the locking mechanism 2 respectively, and write the control logic: When the part is placed on the fixture, the positioning pin 1 is inserted into the main and auxiliary positioning holes, and the locking mechanism 2 clamps the part; after clamping, the proximity switch 5 starts detection. If the nut is detected and the position is qualified (green light is on), the module sends a "welding allowed" signal to the welding equipment; if the nut is not detected or the position is abnormal (red light is on), the module triggers an audible and visual alarm and prohibits welding. At the same time, it controls the locking mechanism 2 to loosen, so that the operator can take out the unqualified part.

[0033] In the mass welding production of passenger car seat mounting brackets, the adoption of this mechanism results in:

[0034] Improved positioning accuracy: The clearance between the positioning pin 1 and the positioning guide sleeve 3 is controlled to be greater than or equal to 0 mm and less than or equal to 0.1 mm. The overall dimensional tolerance of the parts can be stably controlled within ±0.05 mm. The nut position accuracy pass rate has increased from 85% in the traditional method to 99.5%.

[0035] Improved part retrieval and placement efficiency: The traditional third fixed positioning pin 1 is eliminated, and positioning is achieved only through the main and auxiliary positioning holes and the locking mechanism 2. After the part is welded, the locking mechanism 2 can be released to quickly remove it, reducing the part retrieval and placement time from the traditional 15s / piece to 8s / piece.

[0036] Elimination of missing weld risk: The real-time detection of proximity switch 5 can identify 100% of parts with missing weld nuts, preventing unqualified parts from flowing into subsequent assembly processes;

[0037] Reduced maintenance costs: The copper proximity switch protective sleeve 6 effectively isolates welding spatter, extending the service life of the proximity switch 5 from the traditional 1 month to 6 months; the graphite lubrication structure of the positioning guide sleeve 3 reduces the wear of the positioning pin 1, extending the maintenance cycle of the positioning assembly from 2 weeks to 3 months.

Claims

1. A detection positioning mechanism applied to internal nut plate welding, characterized in that: Including positioning assembly, detection assembly and control unit, the positioning assembly, detection assembly are electrically connected with control unit; The positioning assembly includes positioning pin (1), locking mechanism (2) and positioning guide sleeve (3); The theoretical diameter accuracy of the positioning pin (1) is greater than or equal to-0.02mm and less than or equal to 0mm; The locking mechanism (2) is made of 45# steel quenching, and the hardness is greater than or equal to 40HRC and less than or equal to 45HRC; The positioning guide sleeve (3) is a die guide sleeve material, with built-in graphite lubrication structure, and the cooperation gap with the positioning pin (1) is greater than or equal to 0mm and less than or equal to 0.1mm; The detection assembly includes displacement double nut locking structure (4), proximity switch (5) and proximity switch protective sleeve (6), the mechanical grade of the displacement double nut locking structure (4) is not less than 8.8 level, the proximity switch protective sleeve (6) is made of copper, and the inner diameter is 0.1mm larger than the outer diameter of the proximity switch (5); The control unit includes sensor signal lamp (7) and upper signal and PLC signal detection control module (8), the sensor signal lamp (7) is integrated in the proximity switch (5), and the upper signal and PLC signal detection control module (8) is respectively communicated with the proximity switch (5) and the locking mechanism (2).

2. The detection and positioning mechanism for internal nut plate welding according to claim 1, characterized in that: The positioning guide sleeve (3) is fixed in the preset mounting hole of the tool clamp, and the coaxiality deviation of the axis of the positioning guide sleeve (3) and the axis of the part positioning hole is not more than 0.05mm.

3. The detection and positioning mechanism for internal nut plate welding according to claim 1, characterized in that: The displacement double nut locking structure (4) is used for fixing the installation position of the proximity switch (5), and the detection reference of the proximity switch (5) can be calibrated by adjusting the relative position of the double nuts.

4. The detection and positioning mechanism for internal nut plate welding according to claim 1, characterized in that: The preset logic of the control unit is that after the part is clamped, the proximity switch (5) starts detection, sends the welding permission signal when the detection is qualified, triggers the alarm and prohibits welding when the detection is abnormal.

5. The detection and positioning mechanism for internal nut plate welding according to claim 1, characterized in that: The clamping force of the locking mechanism (2) can be adjusted, and the deviation of the fit degree of the part surface when clamping is not more than 0.03mm.

6. The detection and positioning mechanism for internal nut plate welding according to claim 1, characterized in that: The proximity switch (5) is a non-contact sensor, which can detect the distance change and identify the presence or absence of the nut and the position deviation.

7. The detection and positioning mechanism for internal nut plate welding according to claim 1, characterized in that: The sensor signal lamp (7) feeds back the detection state by different colors, green indicates normal detection, and red indicates abnormal detection.

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