Detection device for automatically identifying differential pressure deformation of a lamp shell and method for detecting air tightness thereof

Abstract

The application discloses a detection device for automatically identifying pressure difference deformation of a lamp shell and a gas tightness detection method thereof, and belongs to the technical field of gas tightness detection. The detection device aims at the technical defects that the existing lamp shell gas tightness test only relies on leakage amount determination, and cannot identify the detection unqualification caused by improper detection methods in the detection process, and cannot verify whether the gas tightness performance detection is effective. The application adopts a plane and inclined plane composite support positioning seat, and respectively arranges a micro sensing deformation mechanism. In a mechanical compression reference state, plane and inclined plane strain are collected, and a reference ratio is constructed by combining inclined plane inclination cosine compensation. Then, working ratio is collected under the condition of lamp shell internal and external pressure difference gas tightness test, and the relative change coefficient K of the front and rear ratios is used to identify the deformation caused by the pressure difference expansion of the lamp shell. The application solves the problems of misjudgment of the gas tightness test result caused by unnecessary deformation of the lamp shell due to the detection method and the problem that the gas tightness performance detection cannot be verified whether it is effective.

Description

Technical Field

[0001] This invention relates to the field of airtightness testing technology, and in particular to a detection device and method for automatically identifying differential pressure deformation of lamp housings. Background Technology

[0002] Automotive lighting products generally meet waterproof and dustproof sealing requirements. The lamp housing houses core electrical components such as the light source and circuit board, requiring a sealed structure for overall protection to prevent moisture and dust intrusion that could lead to short circuits, light decay, and component failure. In existing lighting structures, to achieve light guiding, uniform light distribution, and light transmission, a common assembly structure is a lamp housing combined with an independent light guide column. The lamp housing is mostly made of general-purpose injection-molded plastic, while the light guide column is made of polycarbonate (PC), which offers better light transmission and weather resistance. The lamp housing and light guide column are then sealed together.

[0003] After the lamp housing is assembled, a closed gas cavity is formed inside the lamp fixture, with the pressure inside the cavity matching the ambient atmospheric pressure. When the lamp is powered on and lit, the internal light source and circuit board heat up, causing the gas inside the cavity to expand and create a positive pressure relative to the outside atmosphere. After the lamp is powered off and cooled down, the gas inside the cavity contracts, creating a relative negative pressure. Due to the day-night cycle and the temperature fluctuations during start-up and shutdown, a periodic alternating pressure difference is generated inside the lamp fixture cavity, with a maximum amplitude of up to 10 kPa. This causes the assembly surface between the lamp housing and the light guide post to repeatedly open and close. Because there are significant differences in the material properties, shrinkage rate, hardness, and elastic modulus between the lamp housing and the light guide post, problems such as microscopic assembly gaps, uneven fit, and uneven distribution of preload are easily generated at the assembly surface, which can easily lead to sealing failure. Therefore, after the lamp housing is injection molded and the light guide is installed, an airtightness test needs to be performed before leaving the factory. A micro-pressure difference airtightness test is used to determine whether the sealing performance of the lamp housing after the light guide is assembled is up to standard by measuring the amount of air leakage under internal and external pressure difference conditions, and defective products are rejected to ensure that the sealed assembly between the lamp housing and the light guide can meet the waterproof and dustproof requirements of automotive lighting products.

[0004] Current airtightness testing methods mostly employ static differential pressure leak detection. During testing, the lowering sealing plate of the pressing mechanism presses and seals the assembly surface of the lamp housing before testing. However, there is a difference between the pressing of the sealing plate onto the assembly surface of the lamp housing and the sealing method when the lamp housing is actually installed on the lamp fixture using screws. With threaded assembly, the lamp housing only experiences minor deformation on the assembly surface, and the lamp housing itself remains unaffected. However, in airtightness testing, the pressing sealing plate presses and seals the assembly surface of the lamp housing, and the entire lamp housing must bear the pressure. Under the downward pressure, the lamp housing undergoes partial deformation, and the lamp housing shell... Since the body varies in thickness, for the lamp housing, after being pressed and sealed, the thinnest part of the lamp housing deforms first. When measured under conditions of inflation and pressurization or depressurization, the slight deformation of the thinnest part of the lamp housing will further expand, causing the airtightness test to fail. At this time, it will cause a misjudgment of the airtightness performance test of the lamp housing. The failure of the airtightness performance test result is due to the leakage caused by the deformation caused by the pressure of the sealing plate on the lamp housing and the pressure difference deformation. That is to say, the failure of the airtightness performance test result is caused by the improper airtightness performance test method. Therefore, the result of the airtightness performance test at this time cannot represent the sealing performance of the light guide column after the lamp housing is assembled.

[0005] In summary, existing lamp housing airtightness testing technologies and methods are prone to causing unnecessary deformation of the lamp housing, which is a major cause of airtightness performance failure. Existing testing equipment cannot identify failures caused by improper testing methods or verify the effectiveness of airtightness testing. Therefore, there is an urgent need to develop an airtightness testing device and method that can automatically identify differential pressure deformation of the lamp housing. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the prior art and provide an automatic detection device for identifying differential pressure deformation of lamp housings and its airtightness detection method. This solves the problem that the airtightness test results are misjudged due to unnecessary deformation of the lamp housing caused by the detection method after installing light guide columns in existing lamp housing products, and the problem that it is impossible to verify whether the airtightness performance test is effective.

[0007] To address this, the present invention provides the following technical solution: an automatic detection device for identifying differential pressure deformation of lamp housings, comprising a frame, a detection platform, a control platform, and a pressing mechanism on the frame's table surface. The detection platform includes a rotary cylinder mounted on the table surface and a rotatable turntable. The turntable has two positioning seats symmetrically arranged around its center. The rotation of the turntable causes the two positioning seats to rotate alternately below the pressing mechanism. Each positioning seat includes a base body, and the surface of the base body has a positioning groove. The positioning groove has a first support surface parallel to the surface of the base body and a second support surface at an angle θ to the surface of the base body. The lamp housing is positioned by double support using the first support surface as a plane and the second support surface as an inclined plane. A micro-deformation sensing mechanism is installed on the first and second support surfaces. An inner groove is provided on the edge side of the positioning groove. The base body... The upper surface edge is provided with a connecting hole, and the side wall surface of the seat is provided with an air extraction hole connected to the control console. The inner groove, connecting hole, and air extraction hole are interconnected. The pressing mechanism includes an inflation head and a pressing sealing plate, both of which can slide up and down. The inflation head is provided with an inflation hole. During the pressing process, the inflation head first presses the connecting hole to connect, and then the pressing sealing plate presses the surface of the lamp housing. After pressing, the internal structure of the lamp housing forms a sealed cavity. The positive pressure airtightness of the lamp housing is achieved by inflating the sealed cavity through the inflation hole, and the negative pressure airtightness of the lamp housing is achieved by evacuating the sealed cavity through the air extraction hole. The micro-deformation sensing mechanism includes a strain gauge. The strain gauge outputs a strain value by sensing the deformation of the mating surface. In the absence of internal and external pressure difference, the strain value P of the micro-deformation sensing mechanism on the first support surface is... 01 The strain value P of the micro-deformation sensing mechanism on the second support surface 02 The cosine coefficient of the tilt angle θ, the reference ratio R0=P 01 / (P 02 ÷COSθ), under a test pressure difference between the inside and outside of the inflation or deflation, the strain value P of the micro-deformation sensing mechanism on the first support surface. 11 The strain value P of the micro-deformation sensing mechanism on the second support surface 12 The cosine coefficient of the tilt angle θ, and the test ratio R1=P 11 / (P 12 ÷COSθ), the deformation characteristic coefficient K=R1 / R0, the control console uses the threshold range of K to determine whether the differential pressure deformation of the lamp housing is normal, and the threshold is adaptively calibrated according to the material and wall thickness of the lamp housing.

[0008] Furthermore, the pressing mechanism includes a support plate mounted on the platform, a servo electric cylinder on the support plate, a sliding plate that slides up and down on the support plate connected to the telescopic rod end of the servo electric cylinder, a first cylinder and a second cylinder mounted on the sliding plate, an inflation head located at the sliding end of the first cylinder, and a pressing sealing plate located at the telescopic rod end of the second cylinder. By means of the servo electric cylinder, the sliding plate drives the first cylinder and the second cylinder to move downward toward the positioning seat.

[0009] Furthermore, the support plate is provided with a slide rail for the slide plate to slide on, and the bottom of the slide plate is provided with a sliding block corresponding to the slide rail, the sliding block slidingly engaging with the slide rail.

[0010] Furthermore, the support plate is provided with a first limiting block located below the slide rail, and the first limiting block is provided with an adjusting rod. The adjusting rod adjusts the distance of the slide plate sliding on the slide rail and limits the slide plate to adjust the downward stroke of the first cylinder and the second cylinder.

[0011] Furthermore, the first cylinder has a second limiting block at its fixed end and a locking block corresponding to the second limiting block at its sliding end. The second limiting block limits the sliding end of the first cylinder to adjust the downward stroke of the inflation head.

[0012] Furthermore, the lower sealing plate is provided with a sealing strip. After the lower sealing plate is pressed, the sealing strip and the sealing groove of the lamp housing form a sealed connection. The lower sealing plate is provided with a pressure rod protruding from its bottom surface. The pressure rod is directly opposite the light guide column of the lamp housing. The pressure rod abuts against the surface of the light guide column of the lamp housing and is locked and positioned, thereby ensuring that the light guide column deviates and leaks during the positive pressure air tightness test or the negative pressure air tightness test.

[0013] Furthermore, the base body is provided with a sensing clearance hole, which passes through the positioning groove and extends through the side wall of the base body. Laser beam sensors are installed at both ends of the sensing clearance hole. When the positioning groove positions and places the lamp housing, the protrusion of the lamp housing extends between the two sensing clearance holes, and the laser beam sensors are used to detect whether the lamp housing is positioned on the positioning base.

[0014] Furthermore, a conductive sheet is attached to the surface of the strain gauge, and a silicone pad is attached to the surface of the conductive sheet. The lamp housing undergoes micro-deformation under downward pressure or under the action of internal and external pressure difference. This micro-deformation compresses or loosens the silicone pad, allowing it to receive the micro-deformation of the lamp housing. The deformation is then conducted to the strain gauge through the conductive sheet. The strain gauge collects the minute resistance change, converts it into a voltage signal, and then calculates and outputs the strain value using a formula. The silicone pad is made of methyl vinyl silicone with a Shore hardness of 45-50A and a thickness of 1.0-1.2mm.

[0015] Furthermore, the second support surface has an angle θ between its surface and the surface of the seat body of 15~30°.

[0016] Furthermore, a support cylinder is also provided on the platform below the turntable. The telescopic rod end of the support cylinder is connected to a support pad. During testing, the support cylinder extends out of the support pad and supports the turntable, ensuring that the turntable can remain more stable when the pressing mechanism presses down on the positioning seat.

[0017] This invention provides a detection device for automatically identifying differential pressure deformation of lamp housings, and also a method for automatically identifying differential pressure deformation of lamp housings for airtightness detection, comprising the following steps: S1: Position the lamp housing on the positioning seat, so that the first support part of the lamp housing is attached to the first support surface, the second support part of the lamp housing is attached to the second support surface, and the connecting hole of the lamp housing is sealed and clamped on the inner groove, so as to obtain a sealed cavity that connects the internal structural space of the lamp housing and the air extraction and inflation of the positioning seat. Start the rotary cylinder to rotate the turntable 180°, so that the positioning seat with the lamp housing is rotated to the bottom of the pressing mechanism. S2: The pressing mechanism uses a servo electric cylinder to quickly bring the inflation head and the pressing sealing plate close to the positioning seat. First, the first cylinder presses the inflation head further down so that the inflation hole of the inflation head is sealed and abutted with the connection hole of the seat. Then, the second cylinder presses the pressing sealing plate further down so that the sealing strip of the pressing sealing plate is sealed and abutted with the sealing groove of the lamp housing. At the same time as the pressing sealing plate presses down on the lamp housing, the support cylinder is activated, and the support pad supports the turntable synchronously from below. S3: Under the reference steady-state condition with no internal or external pressure difference, collect the strain value P of the micro-deformation sensing mechanism on the first support surface. 01 and the strain value P of the micro-deformation sensing mechanism on the second support surface 02 The strain value of the second support surface is vertically equivalently compensated by the cosine coefficient of the inclination angle θ of the second support surface, and the reference ratio R0=P is calculated. 01 / (P 02 ÷COSθ); S4: Inflate the lamp housing with air through the inflation head or evacuate the lamp housing through the evacuation port to create a test pressure difference of 10-11 kPa between the inside and outside of the lamp housing. Collect the leakage amount and the strain value P of the micro-deformation sensing mechanism on the first support surface. 11 and the strain value P of the micro-deformation sensing mechanism on the second support surface 12 Based on a leakage rate of less than 100 Pa, the sealing performance of the lamp housing is judged to be qualified. For lamp housings that pass the test, the airtightness test process ends directly. For lamp housings that fail the test, the test ratio R1=P is further calculated. 11 / (P 12÷COSθ), calculate the deformation characteristic coefficient K=R1 / R0. Use the threshold range of K to judge whether the pressure difference deformation of the lamp housing is normal. When K falls within the threshold range, the lamp housing has not undergone obvious deformation, and the result of the air tightness test is valid. Otherwise, when K falls outside the threshold range, adjust the adjustment rod to make the first cylinder and the second cylinder press down, and then adjust the press down stroke of the air filling head and the pressing sealing plate to adjust the clamping load, eliminate the pre-deformation of the lamp housing caused by the clamping force, and re-execute the air tightness test process.

[0018] During the positive pressure inflation test, the inflation time is 5-10 seconds and the pressure stabilization time is 5-10 seconds. During the negative pressure vacuum test, the air is first released through the vacuum hole for 2-3 seconds, and then the external vacuum device is activated to vacuum.

[0019] Compared with the prior art, the present invention has the following inventive advantages: 1. This invention indirectly quantifies the differential pressure micro-expansion deformation of the lamp housing by using strain gauges on the first support surface of the plane and the second support surface of the inclined plane to measure the load distribution characteristics of the lamp housing. By using the deformation characteristic coefficient to self-verify the airtightness, this invention solves the problem of misjudgment of airtightness test results caused by leakage due to the pressure of the lower sealing plate on the lamp housing and the deformation caused by differential pressure during the airtightness test.

[0020] 2. This invention uses the deformation characteristic coefficients of the pressure difference before and after to determine the pressure difference, without the need for additional optical detection equipment. It has high integration and low cost. It uses tooling compression strain detection hardware, without the need for external detection modules such as lasers and vision. It has a simple structure and strong anti-interference. Attached Figure Description

[0021] Figure 1 This is one of the schematic diagrams of the three-dimensional structure of an airtightness testing device.

[0022] Figure 2 This is the second schematic diagram of the three-dimensional structure of the airtightness testing device.

[0023] Figure 3 for Figure 1 Main view.

[0024] Figure 4 for Figure 3 Schematic diagram of cross section in the AA direction.

[0025] Figure 5 This is one of the schematic diagrams of the three-dimensional structure of the testing station.

[0026] Figure 6 This is the second schematic diagram of the three-dimensional structure of the testing platform.

[0027] Figure 7 This is a schematic diagram of the three-dimensional structure of the positioning seat.

[0028] Figure 8 A schematic diagram of the exploded three-dimensional structure of the positioning seat.

[0029] Figure 9 This is one of the schematic diagrams of the internal cross-section of the positioning seat after it has been cut open.

[0030] Figure 10 This is the second schematic diagram of the internal cross-section of the positioning seat after it has been cut open.

[0031] Figure 11 This is a schematic diagram of the exploded three-dimensional structure of the micro-deformation sensing mechanism.

[0032] Figure 12 This is one of the schematic diagrams of the three-dimensional structure of the pressing mechanism.

[0033] Figure 13 This is the second schematic diagram of the three-dimensional structure of the pressing mechanism.

[0034] Figure 14 This is a schematic diagram of the three-dimensional structure of the inflation head.

[0035] Figure 15 for Figure 14 Left view.

[0036] Figure 16 for Figure 15 Schematic diagram of cross section in the middle BB direction.

[0037] Figure 17 This is a schematic diagram of the three-dimensional structure of the pressure sealing plate.

[0038] Figure 18 This is a three-dimensional structural diagram of the lamp housing viewed from above.

[0039] Figure 19 This is a three-dimensional structural diagram of the lamp housing viewed from below.

[0040] The components are: 1-frame, 11-tabletop, 12-sensor grating, 13-test button, 2-pressing mechanism, 21-support plate, 211-slide rail, 212-first limit block, 213-adjusting rod, 22-servo cylinder, 23-slide plate, 231-sliding block, 24-first cylinder, 241-second limit block, 242-locking block, 25-second cylinder, 26-inflation head, 261-inflation hole, 27-pressing sealing plate, 271-sealing strip, 272-pressure rod, 3-control console, 4-testing table, 41-turntable, 42-rotary cylinder, 5 - Positioning seat, 51- Seat body, 511- Positioning groove, 512- First support surface, 513- Second support surface, 514- Sensing clearance hole, 515- Hand groove, 516- Inner groove, 517- Air extraction hole, 518- Connecting hole, 52- Laser beam sensor, 53- Micro-deformation sensing mechanism, 531- Strain gauge, 532- Conducting plate, 533- Silicone pad, 6- Lamp housing, 61- Light guide column, 62- Connecting hole, 63- First support part, 64- Second support part, 65- Protrusion, 66- Sealing groove, 7- Support cylinder, 71- Support pad. Detailed Implementation

[0041] The embodiments of the present invention will now be briefly described with reference to the accompanying drawings.

[0042] In an embodiment of the present invention, the structural diagram of the product lamp housing 6 is shown in the figure below. Figure 18 , Figure 19 The lamp housing 6 has a light guide post 61 assembled inside. The lamp housing 6 has an irregular shape. One end of the light guide post 61 has a through hole 62. The other side of the light guide post 61 and the through hole 62 has a first support part 63 and a second support part 64. The first support part 63 is a planar and solid structure with no internal cavity. When the surface of the lamp housing 6 is pressed, the deformation of the first support part 63 is negligible. The second support part 64 is a sloping structure. Its inner side is the internal cavity wall of the lamp housing 6. The angle between the sloping surface of the second support part 64 and the surface of the lamp housing 6 is 16°. There is also a protrusion 65 between the first support part 63 and the second support part 64. The bottom surface of the lamp housing 6 is also provided with a sealing groove 66 so that when it is installed on a lighting product, the sealing ring can seal well. Example 1

[0043] An automatic detection device for identifying differential pressure deformation in lamp housings, referring to... Figures 1-4The device includes a frame 1. The frame 1 has a table 11 with a testing table 4, a control console 3, and a pressing mechanism 2. The upper part of the table 11 has a baffle with three sides surrounding one side of the opening. The edge of the baffle has a sensor grating 12. The sensor grating 12 is used to sense whether there are foreign objects at the opening of the baffle. For example, when manually loading and placing the lamp housing 6, the sensor grating 12 can sense the presence of foreign objects. The sensor grating 12 sends a sensing signal to the control console 3 to cut off the test power supply, so as to prevent the pressing mechanism 2 from injuring the operator. At the same time, there are two test buttons 13 on the table 11 below the baffle. The test buttons 13 need to be pressed with both hands at the same time before the testing device can start the power test.

[0044] Reference Figure 5 , Figure 6 The testing platform 4 includes a rotary cylinder 42 mounted on the platform 11 and a rotatable turntable 41. The turntable 41 has two positioning seats 5 symmetrically arranged around its center. One positioning seat 5 is located on the side of the opening of the baffle on the platform 11, which facilitates the placement of the lamp housing 6 or the removal of the lamp housing 6 after sealing and testing. The other positioning seat 5 is located below the pressing mechanism 2, which facilitates the pressing mechanism 2 pressing down on the lamp housing 6 in the positioning seat 5 for testing. The rotation of the turntable 41 drives the two positioning seats 5 to rotate alternately during the pressing process. Below mechanism 2, the two positioning seats 5 can cycle through the test operation of placing lamp housing 6, testing lamp housing 6, and removing lamp housing 6. A support cylinder 7 is also provided on the table 11 below the turntable 41. The telescopic rod end of the support cylinder 7 is connected to a support pad 71. During the test, the support cylinder 7 extends out of the support pad 71 and supports the turntable 41, ensuring that when the pressing mechanism 2 presses down on the positioning seat 5, the support pad 71 supports the turntable 41 from the bottom, so that the turntable 41 can remain stable after being pressed down.

[0045] Reference Figures 7-10 The positioning base 5 includes a base body 51. The surface of the base body 51 has a positioning groove 511 for positioning the lamp housing 6. A pair of slots 515 are provided on both sides of the positioning groove 511 to facilitate the placement and removal of the lamp housing 6 within the positioning groove 511. The positioning groove 511 has a first support surface 512 parallel to the surface of the base body 51 and a second support surface 513 at an angle θ with the surface of the base body 51. The angle θ between the second support surface 513 and the surface of the base body 51 is 15~30°. Specifically, the second support surface 513 and the base body 51... The included angle θ of the surface is 16°. After the lamp housing 6 is positioned in the positioning groove 511, the lamp housing 6 is positioned by the first support part 63 with the first support surface 512 as the plane support and the second support part 64 with the second support surface 513 as the inclined plane support. The edge side of the positioning groove 511 is provided with an inner groove 516. The upper surface edge of the seat body 51 is provided with a connecting hole 518. The side wall surface of the seat body 51 is provided with a suction hole 517 connected to the control console 3. The inner groove 516, the connecting hole 518 and the suction hole 517 are interconnected.

[0046] The base 51 has a sensing clearance hole 514, which passes through the positioning groove 511 and extends through the side wall of the base 51. Laser beam sensors 52 are installed at both ends of the sensing clearance hole 514. When the lamp housing 6 is positioned in the positioning groove 511, the protrusion 65 of the lamp housing 6 extends between the two sensing clearance holes 514. The laser beam sensors 52 are used to detect whether the lamp housing 6 is positioned in the positioning base 5. When the lamp housing 6 is positioned, the protrusion 65 of the lamp housing 6 blocks the fiber optic signal generated by the laser beam sensors 52. The laser beam sensors 52 can realize the rotation of the turntable 41 through the control console 3, realizing the rotation of the positioning base 5 to switch to the lower pressing mechanism 2.

[0047] A micro-deformation sensing mechanism 53 is installed on the first support surface 512 and the second support surface 513, as shown in the reference. Figure 11 The micro-deformation sensing mechanism 53 includes a strain gauge 531. The strain gauge 531 outputs strain values ​​by sensing the deformation of the contact surface. A conductive sheet 532 is attached to the surface of the strain gauge 531, and a silicone pad 533 is attached to the surface of the conductive sheet 532. The conductive sheet 532 is made of a high-rigidity thin metal sheet, and its compression deformation is much smaller than that of the silicone pad 533. The silicone pad 533 is made of methyl vinyl silicone with a Shore hardness of 45-50A and a thickness of 1.0-1.2mm. The lamp housing 6 undergoes micro-deformation under downward pressure or under the action of internal and external pressure difference. This micro-deformation is transmitted to the strain gauge 531 through the conductive sheet 532 after the silicone pad 533 receives the micro-deformation of the lamp housing 6 and is then converted into a voltage signal by the strain gauge 531. The strain gauge 531 converts the collected minute resistance change into a voltage signal, and then outputs the strain value through a formula. The strain value is expressed as micro-strain, where 1 micro-strain is an elongation of 0.001mm per 1m length, and the unit is 10. -6 m / m.

[0048] Under no internal or external pressure difference, the strain value P of the micro-deformation sensing mechanism 53 on the first support surface 512 01 The strain value P of the micro-deformation sensing mechanism 53 of the second support surface 513 02 The cosine coefficient of the tilt angle θ, the reference ratio R0=P 01 / (P 02 ÷COSθ), the strain value P of the micro-deformation sensing mechanism 53 of the first support surface 512 under a test pressure difference between the inside and outside of the inflation or deflation. 11 The strain value P of the micro-deformation sensing mechanism 53 of the second support surface 513 12 The cosine coefficient of the tilt angle θ, and the test ratio R1=P 11 / (P 12÷COSθ), deformation characteristic coefficient K=R1 / R0, the control console 3 uses the threshold range of K to judge whether the pressure difference deformation of the lamp housing 6 is normal, and the threshold is adaptively calibrated according to the material and wall thickness of the lamp housing 6.

[0049] Reference Figure 12 , Figure 13 The pressing mechanism 2 includes a support plate 21 mounted on the table 11. A servo cylinder 22 is mounted on the support plate 21. The telescopic rod end of the servo cylinder 22 is connected to a slide plate 23 that slides vertically on the support plate 21. A slide rail 211 is provided on the support plate 21 for the slide plate 23 to slide. A sliding block 231 corresponding to the slide rail 211 is provided at the bottom of the slide plate 23. The sliding block 231 slides in cooperation with the slide rail 211, making the servo cylinder 22 slide the slide plate 23 more smoothly and precisely. A first limiting block 212 is provided below the slide rail 211 on the support plate 21. The positioning block 212 is provided with an adjusting rod 213, which is threaded. The adjusting rod 213 is connected to the first limiting block 212 by the thread to adjust the height of the adjustment rod 213. Thus, the adjusting rod 213 adjusts the distance of the sliding plate 23 on the slide rail 211 and limits the sliding plate 23. Finally, it adjusts the downward stroke of the first cylinder 24 and the second cylinder 25, thereby adjusting the degree of pressure of the inflation head 26 at the telescopic rod end of the first cylinder 24 on the positioning seat 5 and the degree of pressure of the downward sealing plate 27 of the telescopic rod of the second cylinder 25 on the lamp housing 6.

[0050] The slide plate 23 is equipped with a first cylinder 24 and a second cylinder 25. The sliding end of the first cylinder 24 is provided with an inflation head 26. The fixed end of the first cylinder 24 is provided with a second limiting block 241, and the sliding end is provided with a locking block 242 corresponding to the second limiting block 241. The second limiting block 241 limits the sliding end of the first cylinder 24 to adjust the downward stroke of the inflation head 26, ensuring that the pressure of the sealing connection between the inflation head 26 and the connecting hole 518 can be adjusted according to the test conditions, thereby realizing the balance between the pressure of the inflation head 26 on the seat 51 and the downward pressure of the sealing plate 27 on the lamp housing 6.

[0051] Reference Figures 14-16 The inflation head 26 has an inflation hole 261 directly above the connection hole 518. The telescopic rod end of the second cylinder 25 has a downward sealing plate 27. (Refer to...) Figure 17The lower sealing plate 27 is provided with a sealing strip 271, which is formed by dispensing and curing adhesive using a dispensing machine. The shape of the sealing strip 271 matches the shape of the sealing groove 66 of the lamp housing 6. The lower sealing plate 27 is provided with a pressure rod 272 protruding from its bottom surface. The pressure rod 272 is directly opposite the light guide column 61 of the lamp housing 6. The pressure rod 272 is used to press and position the light guide column 61. When the lowering mechanism 2 presses down, the servo electric cylinder 22 and the slide plate 23 quickly drive the first cylinder 24 and the second cylinder 25 to move downward toward the positioning seat 5, so that the first cylinder 24 and the second cylinder 25 can quickly approach the lamp housing 6 to be tested. The first cylinder 24 and the second cylinder 25 press in sequence. First, the first cylinder 24 presses down the air head 26 into the connection hole 518 of the seat body 51. The system connects the inflation port 261 to the connection port 518. Then, the second cylinder 25 presses down the sealing plate 27 onto the surface of the lamp housing 6. After the sealing plate 27 is pressed down, the sealing strip 271 and the sealing groove 66 of the lamp housing 6 form a sealed connection. The pressure rod 272 abuts against the surface of the light guide column 61 of the lamp housing 6 and is clamped and positioned. This ensures that the light guide column 61 deviates and leaks during the positive pressure air tightness test or the negative pressure air tightness test. This forms a sealed cavity with the internal structure of the lamp housing 6 as the sealed cavity. The positive pressure air tightness test of the lamp housing 6 is achieved by inflating the sealed cavity with compressed air connected from the outside through the inflation port 261. Alternatively, the negative pressure air tightness test of the lamp housing 6 can be achieved by evacuating the sealed cavity with an externally connected air extraction device through the extraction port 517. Example 2

[0052] An automatic method for detecting the airtightness of lamp housings by identifying differential pressure deformation includes the following steps: S1: Position the lamp housing 6 on the positioning seat 5, so that the first support part 63 of the lamp housing 6 is attached to the first support surface 512, the second support part 64 of the lamp housing 6 is attached to the second support surface 513, and the connecting hole 62 of the lamp housing 6 is sealed and locked on the inner groove 516, so that the internal structural space of the lamp housing 6 and the positioning seat 5 are connected to the air extraction and air inflation of the sealing cavity. Start the rotating cylinder 42 to make the turntable 41 rotate 180°, so that the positioning seat 5 with the lamp housing 6 is rotated to the bottom of the pressing mechanism 2. S2: The pressing mechanism 2 uses the servo electric cylinder 22 to quickly bring the inflation head 26 and the pressing sealing plate 27 close to the positioning seat 5. First, the first cylinder 24 presses the inflation head 26 further down, so that the inflation hole 261 of the inflation head 26 seals and abuts with the connection hole 518 of the seat 51. Then, the second cylinder 25 presses the pressing sealing plate 27 further down, so that the sealing strip 271 of the pressing sealing plate 27 seals and abuts with the sealing groove 66 of the lamp housing 6. At the same time as the pressing sealing plate 27 presses down on the lamp housing 6, the support cylinder 7 is activated, and the support pad 71 synchronously supports the turntable 41 from below. S3: Under the reference steady-state condition with no internal or external pressure difference, collect the strain value P of the micro-deformation sensing mechanism 53 on the first support surface 512. 01 and the strain value P of the micro-deformation sensing mechanism 53 on the second support surface 513 02 The strain value of the second support surface 513 is vertically equivalently compensated by the cosine coefficient of the inclination angle θ of the second support surface 513, and the reference ratio R0=P is calculated. 01 / (P 02 ÷COSθ); S4: Inflate the inside of the lamp housing 6 with air through the inflation head 26 or evacuate the inside of the lamp housing 6 through the evacuation port 517 to create a test pressure difference of 10-11 kPa between the inside and outside of the lamp housing 6, and collect the leakage amount and the strain value P of the micro-deformation sensing mechanism 53 on the first support surface 512. 11 and the strain value P of the micro-deformation sensing mechanism 53 on the second support surface 513 12 Based on a leakage rate of less than 100 Pa, the sealing performance of lamp housing 6 is judged to be qualified. For lamp housing 6 that passes the test, the airtightness test process ends directly. For lamp housing 6 that fails the test, the test ratio R1=P is further calculated. 11 / (P 12 ÷COSθ), calculate the deformation characteristic coefficient K=R1 / R0. Use the threshold range of K to judge whether the differential pressure deformation of the lamp housing 6 is normal. When K falls within the threshold range, the lamp housing 6 does not have obvious deformation, and the result of the air tightness test is valid. Otherwise, when K falls outside the threshold range, adjust the adjustment rod 213 to make the first cylinder 24 and the second cylinder 25 press down, and then adjust the pressing stroke of the air filling head 26 and the pressing sealing plate 27 to adjust the clamping load, eliminate the pre-deformation of the lamp housing 6 caused by the clamping force, and re-execute the air tightness test process.

[0053] During the positive pressure inflation test, the inflation time is 5-10 seconds and the pressure stabilization time is 5-10 seconds. During the negative pressure vacuum test, the air is first released through the vacuum hole 517 for 2-3 seconds, and then the external vacuum device is activated to vacuum.

[0054] The threshold range of K was determined by the following method: The injection-molded lamp housing 6 was taken. The material used for the lamp housing 6 was ABS material, and the wall thickness of the lamp housing 6 was 1.2~1.4mm. The lamp housing 6 did not have the light guide post 61 installed. The lamp housing 6 was filled and cured with sealant at the installation location of the light guide post 61, so that the lamp housing 6 at the installation location of the light guide post 61 and the internal structure of the lamp housing 6 were completely sealed. After the sealant was completely cured, the lamp housing 6 was placed in the positioning groove 511 for positioning. The lamp housing 6 was pressed tightly by the pressing sealing plate 27 of the pressing mechanism 2. The pressing sealing plate 27 applied different pressures of 15N, 20N, 25N, 30N, and 35N to the surface of the lamp housing 6. The pressure difference between the positive pressure of inflation and the negative pressure of vacuum was 10kPa. The angle θ between the second support surface 513 of the lamp housing 6 and the surface of the base 51 was 16°, i.e., COSθ was 0.9613. The measurement results are as follows:

[0055] The test results show that when the clamping load is 15~30N, the positive inflation pressure K=0.952~0.992 and the negative suction pressure K=1.016~1.043, the leakage is less than 100Pa, and the pressure difference deformation of the lamp housing 6 is normal deformation, so the test results are valid. When the clamping load is >30N, the positive inflation pressure K=0.944 and the negative suction pressure K=1.065, the pressure difference deformation of the lamp housing 6 is excessive deformation and will cause sealing leakage, with the leakage exceeding 100Pa. Under this condition, the test results of the lamp housing 6 are not due to poor sealing performance of the light guide column 61 of the lamp housing 6. Therefore, the test results are invalid, and the pressure needs to be adjusted and retested for judgment.

[0056] The test results show that the material used for lamp housing 6 is ABS material, the wall thickness of lamp housing 6 is 1.2~1.4mm, the threshold range of K value is 0.95~1.0 under positive pressure airtight condition; and the threshold range of K value is 1.0~1.05 under negative pressure airtight condition.

[0057] During the test, the lamp housing 6 was filled and cured with sealant at the mounting position of the light guide post 61. Therefore, the sealing performance of the lamp housing 6 itself was qualified. However, the sealing leakage test result in the above-mentioned measurement process was caused by the deformation of the lamp housing 6 under pressure difference. Therefore, the threshold range of the K value measured above can effectively evaluate the influence of the lamp housing 6 under pressure difference deformation during the test. Furthermore, whether the K value falls within the threshold range can be used to determine whether the failure of this sealing performance test is reliable.

[0058] The above embodiments merely illustrate implementation methods of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention.

Claims

1. A detection device for automatically identifying differential pressure deformation of lamp housings, characterized in that: The machine includes a frame (1), and the table (11) of the frame (1) is provided with a testing table (4), a control console (3) and a pressing mechanism (2). The testing table (4) includes a rotary cylinder (42) and a rotatable turntable (41) mounted on the table (11). The turntable (41) has two positioning seats (5) symmetrically arranged around the center. The rotation of the turntable (41) drives the two positioning seats (5) to rotate alternately below the pressing mechanism (2). The positioning seat (5) includes a seat body (51), and the surface of the seat body (51) is provided with a positioning groove (511). The positioning groove (511) has a first support surface (512) parallel to the surface of the base (51) and a second support surface (513) at an angle θ to the surface of the base (51). The lamp housing (6) is positioned by double support with the first support surface (512) as a plane support and the second support surface (513) as an inclined support. A micro-deformation sensing mechanism (53) is installed on the first support surface (512) and the second support surface (513). The edge side of the positioning groove (511) is provided with an inner groove (516). The base (51) The upper surface edge is provided with a connecting hole (518), and the side wall surface of the seat (51) is provided with an air extraction hole (517) connected to the control console (3). The inner groove (516), the connecting hole (518) and the air extraction hole (517) are interconnected. The pressing mechanism (2) includes an inflation head (26) that can slide up and down and a pressing sealing plate (27). The inflation head (26) is provided with an inflation hole (261). During the pressing process of the pressing mechanism (2), the inflation head (26) first presses and connects with the connecting hole (518), and the pressing sealing plate (261) first presses and connects with the connecting hole (518). 7) Press the surface of the lamp housing (6) again. After pressing, the internal structure of the lamp housing (6) forms a sealed cavity. The positive pressure airtightness of the lamp housing (6) is achieved by inflating the sealed cavity through the air inlet (261), and the negative pressure airtightness of the lamp housing (6) is achieved by evacuating the sealed cavity through the air extraction hole (517). The micro-deformation sensing mechanism (53) includes a strain gauge (531). The strain gauge (531) outputs the strain value by sensing the deformation of the bonding surface. Under no internal or external pressure difference, the strain value P of the micro-deformation sensing mechanism (53) on the first support surface (512) is... 01 The strain value P of the micro-deformation sensing mechanism (53) of the second support surface (513) 02 The cosine coefficient of the tilt angle θ, the reference ratio R0=P 01 / (P 02 ÷COSθ), under a test pressure difference between the inside and outside of the inflation or deflation, the strain value P of the micro-deformation sensing mechanism (53) of the first support surface (512) is... 11 The strain value P of the micro-deformation sensing mechanism (53) of the second support surface (513) 12 The cosine coefficient of the tilt angle θ, and the test ratio R1=P 11 / (P 12 ÷COSθ), deformation characteristic coefficient K=R1 / R0, the control console (3) uses the threshold range of K to judge whether the pressure difference deformation of the lamp housing (6) is normal, and the threshold is adaptively calibrated according to the material and wall thickness of the lamp housing (6).

2. The detection device for automatically identifying differential pressure deformation of lamp housings according to claim 1, characterized in that: The pressing mechanism (2) includes a support plate (21) installed on the table (11). A servo electric cylinder (22) is provided on the support plate (21). The telescopic rod end of the servo electric cylinder (22) is connected to a sliding plate (23) that slides up and down on the support plate (21). The sliding plate (23) is equipped with a first cylinder (24) and a second cylinder (25). The inflation head (26) is located at the sliding end of the first cylinder (24). The pressing sealing plate (27) is located at the telescopic rod end of the second cylinder (25). By means of the servo electric cylinder (22), the sliding plate (23) drives the first cylinder (24) and the second cylinder (25) to move downward toward the positioning seat (5).

3. The detection device for automatically identifying differential pressure deformation of lamp housings according to claim 2, characterized in that: The support plate (21) is provided with a slide rail (211) for the slide plate (23) to slide. The bottom of the slide plate (23) is provided with a sliding block (231) corresponding to the slide rail (211). The sliding block (231) slides in cooperation with the slide rail (211). The support plate (21) is provided with a first limiting block (212) located below the slide rail (211). The first limiting block (212) is provided with an adjusting rod (213). The adjusting rod (213) adjusts the distance of the slide plate (23) sliding on the slide rail (211) and limits the slide plate (23) to adjust the downward stroke of the first cylinder (24) and the second cylinder (25).

4. The detection device for automatically identifying differential pressure deformation of lamp housings according to claim 2, characterized in that: The first cylinder (24) has a second limiting block (241) at its fixed end and a locking block (242) corresponding to the second limiting block (241) at its sliding end. The second limiting block (241) limits the sliding end of the first cylinder (24) to adjust the downward stroke of the inflation head (26).

5. The detection device for automatically identifying differential pressure deformation of lamp housings according to claim 1, characterized in that: The lower sealing plate (27) is provided with a sealing strip (271). After the lower sealing plate (27) is pressed, the sealing strip (271) and the sealing groove (66) of the lamp housing (6) form a sealed connection. The lower sealing plate (27) is provided with a pressure rod (272) protruding from its bottom surface. The pressure rod (272) is directly opposite the light guide column (61) of the lamp housing (6). The pressure rod (272) abuts against the surface of the light guide column (61) of the lamp housing (6) and is clamped and positioned.

6. The detection device for automatically identifying differential pressure deformation of lamp housings according to claim 1, characterized in that: The base (51) has a sensing clearance hole (514). The sensing clearance hole (514) passes through the positioning groove (511) and extends through the side wall of the base (51). Laser beam sensors (52) are installed at both ends of the sensing clearance hole (514). When the positioning groove (511) positions and places the lamp housing (6), the protrusion (65) of the lamp housing (6) extends between the two sensing clearance holes (514) and the laser beam sensors (52) are used to sense whether the lamp housing (6) is positioned on the positioning base (5).

7. The detection device for automatically identifying differential pressure deformation of lamp housings according to claim 1, characterized in that: The strain gauge (531) has a conductive sheet (532) attached to its surface, and the conductive sheet (532) has a silicone pad (533) attached to its surface. The lamp housing (6) undergoes micro-deformation under downward pressure or under the action of internal and external pressure difference. The micro-deformation compresses or loosens the silicone pad (533), so that the silicone pad (533) receives the micro-deformation of the lamp housing (6) and transmits it to the strain gauge (531) through the conductive sheet (532). The strain gauge (531) converts the collected minute resistance change into a voltage signal, and then outputs the strain value through the formula. The silicone pad (533) is made of methyl vinyl silicone, with a Shore hardness of 45-50A and a thickness of 1.0-1.2mm.

8. The detection device for automatically identifying differential pressure deformation of lamp housings according to claim 1, characterized in that: The second support surface (513) has an angle θ between its surface and the surface of the seat (51) of 15~30°.

9. The detection device for automatically identifying differential pressure deformation of lamp housings according to claim 1, characterized in that: The platform (11) is also provided with a support cylinder (7) located below the turntable (41). The telescopic rod end of the support cylinder (7) is connected to a support pad (71). During the test, the support cylinder (7) extends out of the support pad (71) and supports the turntable (41).

10. An automatic method for detecting the airtightness of a lamp housing under differential pressure deformation, characterized in that, The detection device for automatically identifying differential pressure deformation of lamp housings as described in any one of claims 1 to 9 includes the following steps: S1: Position the lamp housing (6) on the positioning seat (5), so that the first support part (63) of the lamp housing (6) is attached to the first support surface (512), the second support part (64) of the lamp housing (6) is attached to the second support surface (513), and the connecting hole (62) of the lamp housing (6) is sealed and clamped on the inner groove (516), so that the internal structural space of the lamp housing (6) and the positioning seat (5) are connected to the air extraction and air filling of the sealed cavity. Start the rotary cylinder (42) to make the turntable (41) rotate 180°, so that the positioning seat (5) with the lamp housing (6) is rotated below the pressing mechanism (2); S2: The pressing mechanism (2) uses a servo cylinder (22) to quickly bring the inflation head (26) and the pressing sealing plate (27) close to the positioning seat (5). First, the first cylinder (24) presses the inflation head (26) further down so that the inflation hole (261) of the inflation head (26) is sealed and abutted with the connection hole (518) of the seat (51). Then, the second cylinder (25) presses the pressing sealing plate (27) further down so that the sealing strip (271) of the pressing sealing plate (27) is sealed and abutted with the sealing groove (66) of the lamp housing (6). At the same time as the pressing sealing plate (27) presses down on the lamp housing (6), the support cylinder (7) is activated and the support pad (71) supports the turntable (41) from below. S3: Under the reference steady-state condition with no internal or external pressure difference, the strain value P of the micro-deformation sensing mechanism (53) on the first support surface (512) is collected. 01 and the strain value P of the micro-deformation sensing mechanism (53) on the second support surface (513). 02 The strain value of the second support surface (513) is vertically equivalently compensated by the cosine coefficient of the inclination angle θ of the second support surface (513), and the reference ratio R0=P is calculated. 01 / (P 02 ÷COSθ); S4: Inflate the inside of the lamp housing (6) with air through the inflation head (26) or evacuate the inside of the lamp housing (6) through the evacuation hole (517) to create a test pressure difference of 10-11 kPa between the inside and outside of the lamp housing (6), and collect the leakage amount and the strain value P of the micro-deformation sensing mechanism (53) on the first support surface (512). 11 and the strain value P of the micro-deformation sensing mechanism (53) on the second support surface (513). 12 Based on a leakage rate of less than 100 Pa, the sealing performance of the lamp housing (6) is judged to be qualified. For lamp housings (6) that pass the test, the airtightness test process is directly terminated. For lamp housings (6) that fail the test, the test ratio R1=P is further calculated. 11 / (P 12 ÷COSθ), calculate the deformation characteristic coefficient K=R1 / R0, and use the threshold range of K to judge whether the pressure difference deformation of the lamp housing (6) is normal. When K falls within the threshold range, the lamp housing (6) has not undergone obvious deformation, and the result of the air tightness test is valid. Otherwise, when K falls outside the threshold range, adjust the adjustment rod (213) to make the first cylinder (24) and the second cylinder (25) press down, and then adjust the press down stroke of the air filling head (26) and the pressing sealing plate (27) to adjust the clamping load, eliminate the pre-deformation of the lamp housing (6) caused by the clamping force, and re-execute the air tightness test process; During the positive pressure inflation test, the inflation time is 5~10s and the pressure stabilization time is 5~10s. During the negative pressure vacuum test, the air is first released through the vacuum hole (517) for 2~3s, and then the external vacuum device is activated to vacuum.

Images